Decreased, Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII)

PR:000011405

PR COUP transcription factor 2

CHEBI:79436

CHEBI 17beta-Hydroxy-2-oxa-5alpha-androstan-3-one

UBERON:0000057

UBERON urethra

UBERON:0010418

UBERON urethral opening

GO:0035624

GO receptor transactivation

GO:0050810

GO regulation of steroid biosynthetic process

GO:0042446

GO hormone biosynthetic process

GO:0048645

GO animal organ formation

GO:0010159

GO specification of animal organ position

WIKI decreased

WIKI abnormal

WikiUser_17

mammals

WikiUser_28

Vertebrates

WCS_9606

common toxicological species human

10090

NCBI mouse

10116

NCBI rat

Decreased, Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII)

Decreased COUP-TFII in Leydig cells

Cellular

Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII), also known as Nuclear Receptor Subfamily 2 Group F Member 2 (NR2F2) (Mendoza-Villarroel et al. 2014), is a nuclear receptor involved in various metabolic systems including lipid regulation and steroid synthesis (Qin et al. 2008; van den Driesche et al. 2012; Ashraf et al. 2018).   COUP-TFII has been shown to interact with Retinoid X Receptor (RXR) and Glucocorticoid Receptor (GR) (Ashraf et al. 2018).  Decrease in COUP-TFII expression has been linked to metabolic and developmental disorders.

COUP-TFII is measured by changes in gene expression and protein levels.  Effects of COUP-TFII on expression of downstream genes can be investigating using metabolomics and RT-qPCR approaches.  In addition, targeted ToxCast assays using SeqAPASS evaluations can evaluate gene expression changes from chemical exposure for model species (NCBI Accession Number NP_066285.1 for NR2F2 in Lalone et al. 2018).

Life Stage: Applies to all life stages. Sex: Applies to both males and females. Taxonomic: Most representative studies have been done in mammals (humans, lab mice, lab rats); plausible for all vertebrates.

CL:0000255

CL eukaryotic cell

Moderate Unspecific

High

Development

Moderate

Ashraf, U.M., Sanchez, E.R., and Kumarasamy, S.  2019.  COUP-TFII Revisited: Its Role in Metabolic Gene Regulation.  Steroids 141: 63–69. LaLone, C.A., Villeneuve, D.L., Doering, J.A., Blackwell, B.R., Transue, T.R., Simmons, C.W., Swintek, J., Degitz, S.J., Williams, A.J., and Ankley, G.T.  2018.  Evidence for Cross Species Extrapolation of Mammalian-Based High-Throughput Screening Assay Results.  Environmental Science and Technology 52: 13960−13971. Mendoza-Villarroel, R.E., Robert, N.M., Martin, L.J., Brousseau, C., and Tremblay, J.J.  2014.  The Nuclear Receptor NR2F2 Activates Star Expression and Steroidogenesis in Mouse MA-10 and MLTC-1 Leydig Cells.  Biology of Reproduction 91(1) Article 26: 1-12. Qin, J., Tsai, M.-J., and Tsai S.Y.  2008.  Essential Roles of COUP-TFII in Leydig Cell Differentiation and Male Fertility.  Public Library of Science One 3(9): e3285. van den Driesche, S., Walker, M., McKinnel, C., Scott, HM., Eddie, S.L., Mitchell, R.T., Seckl, J.R., Drake, A.J., Smith, L.B., Anderson, R.A., and Sharpe, R.M.  2012.  Proposed Role for COUP-TFII in Regulating Fetal Leydig Cell Steroidogenesis, Perturbation of Which Leads to Masculinization Disorders in Rodents. Public Library of Science One 7(5): e37064.   NOTE: Italics symbolize edits from John Frisch     AOPWiki 2016-11-29T18:41:26

2024-04-16T09:08:50

Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells

Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes

Cellular

Steroids are hormones that play important roles in reproductive development and function.  Multiple pathways control the rate of steroidogenesis ensuring that proper steroid levels are present during development.  Decreased steroidogenesis rates of androgens has been linked to malformation of reproductive organs and decreased reproduction function (see Palermo et al. 2021 for review with focus on exposure to phthalates).  Efforts have been made to isolate when steroidogenesis rates and resulting steroid levels are most critical for proper reproductive development in lab mammals by targeted disruption by toxicants during different periods of development (Foster and Harris 2005; Welsh 2008).

Rates of steroidogenesis are measured by changes in gene expression and protein levels.  Gene/protein families with known effects on regulation (ex. STAR steroidogenic acute regulatory protein (STaR)) or production of androgens (ex. Cytochrome P450 11 (CYP11); Cytochrome P450 17 (CYP17); 3β-Hydroxysteroid dehydrogenase (3 β-HSD)) are typically studied (Qin et al. 2008; van den Driesche et al. 2012; Mendoza-Villarroel et al. 2014).  Effects on expression of downstream genes can be investigating using metabolomics and RT-qPCR approaches, as well as measuring steroid levels (often testosterone).  In addition, targeted ToxCast assays using SeqAPASS evaluations can evaluate gene expression changes from chemical exposure for model species (HT-H295R assay in Lalone et al. 2018).

CL:0000255

CL eukaryotic cell

Moderate Unspecific

High

Development

Moderate

Foster, P.M.D. and Harris, M.W.  2005.  Changes in Androgen-Mediated Reproductive Development in Male Rat Offspring Following Exposure to a Single Oral Dose of Flutamide at Different Gestational Ages.  Toxicological Sciences 85: 1024–1032. LaLone, C.A., Villeneuve, D.L., Doering, J.A., Blackwell, B.R., Transue, T.R., Simmons, C.W., Swintek, J., Degitz, S.J., Williams, A.J., and Ankley, G.T.  2018.  Evidence for Cross Species Extrapolation of Mammalian-Based High-Throughput Screening Assay Results.  Environmental Science and Technology 52: 13960−13971. Mendoza-Villarroel, R.E., Robert, N.M., Martin, L.J., Brousseau, C., and Tremblay, J.J.  2014.  The Nuclear Receptor NR2F2 Activates Star Expression and Steroidogenesis in Mouse MA-10 and MLTC-1 Leydig Cells.  Biology of Reproduction 91(1) Article 26: 1-12. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Qin, J., Tsai, M.-J., and Tsai S.Y.  2008.  Essential Roles of COUP-TFII in Leydig Cell Differentiation and Male Fertility.  Public Library of Science One 3(9): e3285. van den Driesche, S., Walker, M., McKinnel, C., Scott, HM., Eddie, S.L., Mitchell, R.T., Seckl, J.R., Drake, A.J., Smith, L.B., Anderson, R.A., and Sharpe, R.M.  2012.  Proposed Role for COUP-TFII in Regulating Fetal Leydig Cell Steroidogenesis, Perturbation of Which Leads to Masculinization Disorders in Rodents. Public Library of Science One 7(5): e37064. Welsh, M., Saunders, P.T.K., Fisken, M., Scott, H.M., Hutchison, G.R., Smith, L.R. and Sharpe, R.M.  2008.  Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism.  Journal of Clinical Investigation 118(4): 1479-1490. NOTE: Italics symbolize edits from John Frisch     AOPWiki 2016-11-29T18:41:26

2024-04-16T10:07:31

Decrease, dihydrotestosterone (DHT) level

Decrease, DHT level

Tissue

Dihydrotestosterone (DHT) is an endogenous steroid hormone and a potent androgen. The level of DHT in tissue or blood is dependent on several factors, such as the synthesis, uptake/release, metabolism, and elimination from the system, which again can be dependent on biological compartment and developmental stage. DHT is primarily synthesized from testosterone (T) via the irreversible enzymatic reaction facilitated by 5α-Reductases (5α-REDs) (Swerdloff et al., 2017). Different isoforms of this enzyme are differentially expressed in specific tissues (e.g. prostate, skin, liver, and hair follicles) at different developmental stages, and depending on disease status (Azzouni et al., 2012; Uhlén et al., 2015), which ultimately affects the local production of DHT. An alternative (“backdoor”) pathway , exists for DHT formation that is independent of T and androstenedione as precursors. While first discovered in marsupials, the physiological importance of this pathway has now also been established in other mammals including humans (Renfree and Shaw, 2023). This pathway relies on the conversion of progesterone (P) or 17-OH-P to androsterone and then androstanediol through several enzymatic reactions and finally, the conversion of androstanediol into DHT probably by HSD17B6 (Miller & Auchus, 2019; Naamneh Elzenaty et al., 2022). The “backdoor” synthesis pathway is a result of an interplay between placenta, adrenal gland, and liver during fetal life (Miller & Auchus, 2019). The conversion of T to DHT by 5α-RED in peripheral tissue is mainly responsible for the circulating levels of DHT, though some tissues express enzymes needed for further metabolism of DHT consequently leading to little release and contribution to circulating levels (Swerdloff et al.). The initial conversion of DHT into inactive steroids is primarily through 3α-hydroxysteroid dehydrogenase (3α-HSD) and 3β-HSD in liver, intestine, skin, and androgen-sensitive tissues. The subsequent conjugation is mainly mediated by uridine 5´-diphospho (UDP)-glucuronyltransferase 2 (UGT2) leading to biliary and urinary elimination from the system. Conjugation also occurs locally to control levels of highly potent androgens (Swerdloff et al., 2017). Disruption of any of the aforementioned processes may lead to decreased DHT levels, either systemically or at tissue level.

Several methods exist for DHT identification and quantification, such as conventional immunoassay methods (ELISA or RIA) and advanced analytical methods as liquid chromatography tandem mass spectrometry (LC-MS/MS). The methods can have differences in detection and quantification limits, which should be considered depending on the DHT levels in the sample of interest. Further, the origin of the sample (e.g. cell culture, tissue, or blood) will have implications for the sample preparation. Conventional immunoassays have limitations in that they can overestimate the levels of DHT compared to levels determined by gas chromatography mass spectrometry and liquid chromatography tandem mass spectrometry (Hsing et al., 2007; Shiraishi et al., 2008). This overestimation may be explained by lack of specificity of the DHT antibody used in the RIA and cross-reactivity with T in samples (Swerdloff et al., 2017). Test guideline no. 456 (OECD 2023) uses a cell line, NCI-H295, capable of producing DHT at low levels. The test guideline is not validated for this hormone. Measurement of DHT levels in these cells require low detection and quantification limits. Any effect on DHT can be a result of many upstream molecular events that are specific for the NCI-H295 cells, and which may differ in other models for steroidogenesis.

This KE is applicable to both sexes, across developmental stages and adulthood, in many different tissues and across mammals. In both humans and rodents, DHT is important for the in utero differentiation and growth of the prostate and male external genitalia (Azzouni et al., 2012; Gerald & Raj, 2022). Besides its critical role in development, DHT also induces growth of facial and body hair during puberty in humans (Azzouni et al., 2012). In mammals, the role of DHT in females is less established (Swerdloff et al., 2017), however studies suggest that androgens are important in e.g. bone metabolism and growth, as well as female reproduction from follicle development to parturition (Hammes & Levin, 2019). It is, however, acknowledged that this KE most likely has a much broader domain of applicability extending to non-mammalian vertebrates. AOP developers are encouraged to add additional relevant knowledge to expand on the applicability to also include other vertebrates.

High Mixed

Moderate

All life stages

High

Azzouni, F., Godoy, A., Li, Y., & Mohler, J. (2012). The 5 alpha-reductase isozyme family: A review of basic biology and their role in human diseases. In Advances in Urology. https://doi.org/10.1155/2012/530121 Gerald, T., & Raj, G. (2022). Testosterone and the Androgen Receptor. In Urologic Clinics of North America (Vol. 49, Issue 4, pp. 603–614). W.B. Saunders. https://doi.org/10.1016/j.ucl.2022.07.004 Hammes, S. R., & Levin, E. R. (2019). Impact of estrogens in males and androgens in females. In Journal of Clinical Investigation (Vol. 129, Issue 5, pp. 1818–1826). American Society for Clinical Investigation. https://doi.org/10.1172/JCI125755 Hsing, A. W., Stanczyk, F. Z., Bélanger, A., Schroeder, P., Chang, L., Falk, R. T., & Fears, T. R. (2007). Reproducibility of serum sex steroid assays in men by RIA and mass spectrometry. Cancer Epidemiology Biomarkers and Prevention, 16(5), 1004–1008. https://doi.org/10.1158/1055-9965.EPI-06-0792 Miller, W. L., & Auchus, R. J. (2019). The “backdoor pathway” of androgen synthesis in human male sexual development. PLoS Biology, 17(4). https://doi.org/10.1371/journal.pbio.3000198 Naamneh Elzenaty, R., du Toit, T., & Flück, C. E. (2022). Basics of androgen synthesis and action. In Best Practice and Research: Clinical Endocrinology and Metabolism (Vol. 36, Issue 4). Bailliere Tindall Ltd. https://doi.org/10.1016/j.beem.2022.101665 OECD (2023), Test No. 456: H295R Steroidogenesis Assay, OECD Guidelines for the Testing of Chemicals, Section 4, OECD Publishing, Paris, https://doi.org/10.1787/9789264122642-en. Renfree, M. B., and Shaw, G. (2023). The alternate pathway of androgen metabolism and window of sensitivity. J. Endocrinol., JOE-22-0296. doi:10.1530/JOE-22-0296. Shiraishi, S., Lee, P. W. N., Leung, A., Goh, V. H. H., Swerdloff, R. S., & Wang, C. (2008). Simultaneous measurement of serum testosterone and dihydrotestosterone by liquid chromatography-tandem mass spectrometry. Clinical Chemistry, 54(11), 1855–1863. https://doi.org/10.1373/clinchem.2008.103846 Swerdloff, R. S., Dudley, R. E., Page, S. T., Wang, C., & Salameh, W. A. (2017). Dihydrotestosterone: Biochemistry, physiology, and clinical implications of elevated blood levels. In Endocrine Reviews (Vol. 38, Issue 3, pp. 220–254). Endocrine Society. https://doi.org/10.1210/er.2016-1067 Uhlén, M., Fagerberg, L., Hallström, B. M., Lindskog, C., Oksvold, P., Mardinoglu, A., Sivertsson, Å., Kampf, C., Sjöstedt, E., Asplund, A., Olsson, I. M., Edlund, K., Lundberg, E., Navani, S., Szigyarto, C. A. K., Odeberg, J., Djureinovic, D., Takanen, J. O., Hober, S., … Pontén, F. (2015). Tissue-based map of the human proteome. Science, 347(6220). https://doi.org/10.1126/science.1260419 AOPWiki 2019-04-10T05:02:29

2024-04-05T08:10:32

Impaired, urethral tube closure

Organ

Failure of the urethral tube to properly close and abnormal urethra formation are indicative of improper reproductive organ formation during development, which can impact proper reproductive function (see Palermo et al. 2021 for review with focus on exposure to phthalates).  Research in laboratory mammals has focused on the levels of steroid compounds necessary for proper reproductive development (Kim et al. 2010; Suzuki et al. 2015; Shi et al. 2024), and the targeted disruption by toxicants during different periods of development (Foster and Harris 2005; Welsh et al. 2008).

Histological observations are required to detect failure for the urethra to develop, as well as other abnormalities with the urethra and surrounding reproductive tissue.

Life Stage: Problems first can be observed during development, with adverse outcome manifesting in mature individuals. Sex: Applies to both males and females. Taxonomic: Most representative studies have been done in mammals (humans, lab mice, lab rats); plausible for all vertebrates.

Moderate Unspecific

Moderate

During development and at adulthood

Moderate

2024-04-16T14:17:12

Hypospadias, increased

Hypospadias

Organ

Hypospadias is a congenital condition in which the urethral opening is not at the tip of the penis, usually occurring on the underside of the penis.  Improper reproductive organ formation occurring during development can impact proper reproductive function (see Palermo et al. 2021 for review with focus on exposure to phthalates).  Research in laboratory mammals has focused on signaling and gene expression (van den Driesche et al. 2012; Mendoza-Villarroel et al. 2014)), the levels of steroid compounds necessary for proper reproductive development (Kim et al. 2010; Suzuki et al. 2015; Shi et al. 2024), and the targeted disruption by toxicants during different periods of development (Foster and Harris 2005; Welsh et al. 2008).  In addition, clinical studies in humans affected by hypospadias have attempted to find causative factors (see overview in Foster 2006).

Direct observation of hypospadias is possible when individuals don’t have an urethral opening at the tip of the penis.

Life Stage: Problems first can be observed during development, with adverse outcome manifesting in mature individuals. Sex: Applies to males. Taxonomic: Most representative studies have been done in mammals (humans, lab mice, lab rats) with clinical observations in humans; plausible for all vertebrates.

High Male

High

During development and at adulthood

High High High

Foster, P.M.D. and Harris, M.W.  2005.  Changes in Androgen-Mediated Reproductive Development in Male Rat Offspring Following Exposure to a Single Oral Dose of Flutamide at Different Gestational Ages.  Toxicological Sciences 85: 1024–1032. Foster, P.M.D.  2006.  Disruption of reproductive development in male rat offspring following in utero exposure to phthalate esters.  International Journal of Andrology 29: 140–147. Kim, T.S., Jung, K.K., Kim, S.S., Kang, I.H., Baek, J.H., Nam, H.-S., Hong, S.-K., Lee, B.M., Hong, J.T., Oh, K.W., Kim, H.S., Han, S.Y., and Kang, T.S.  2010.  Effects of in Utero Exposure to DI(n-Butyl) Phthalate on Development of Male Reproductive Tracts in Sprague-Dawley Rats.  Journal of Toxicology and Environmental Health, Part A 73(21-22): 1544-1559. Mendoza-Villarroel, R.E., Robert, N.M., Martin, L.J., Brousseau, C., and Tremblay, J.J.  2014.  The Nuclear Receptor NR2F2 Activates Star Expression and Steroidogenesis in Mouse MA-10 and MLTC-1 Leydig Cells.  Biology of Reproduction 91(1) Article 26: 1-12. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Shi, B. He, E., Chang, K., Xu, G., Meng, Q., Xu, H., Chen, Z., Wang, X., Jia, M., Sun, W., Zhao, W., Zhao, H., Dong, L., and Cui, H.  2024.  Genistein prevents the production of hypospadias induced by Di-(2-ethylhexyl) phthalate through androgen signaling and antioxidant response in rats.  Journal of Hazardous Materials 466: 133537. Suzuki, H., Suzuki, K., and Yamada, G.  2015.  Systematic analyses of murine masculinization processes based on genital sex differentiation parameters.  Development, Growth, and Differentiation 57: 639–647. van den Driesche, S., Walker, M., McKinnel, C., Scott, HM., Eddie, S.L., Mitchell, R.T., Seckl, J.R., Drake, A.J., Smith, L.B., Anderson, R.A., and Sharpe, R.M.  2012.  Proposed Role for COUP-TFII in Regulating Fetal Leydig Cell Steroidogenesis, Perturbation of Which Leads to Masculinization Disorders in Rodents. Public Library of Science One 7(5): e37064. Welsh, M., Saunders, P.T.K., Fisken, M., Scott, H.M., Hutchison, G.R., Smith, L.B., and Sharpe, R.M.  2008.  Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism.  The Journal of Clinical Investigation 118(4): 1479–1490. NOTE: Italics symbolize edits from John Frisch     AOPWiki 2022-12-18T10:39:05

2024-04-16T16:12:40

<upstream-id>8b52017c-c3fc-4ae0-827b-20ab1d07720d</upstream-id> <downstream-id>4db4c44f-5c70-4208-8372-5a76fc455633</downstream-id> In this key event relationship we are focused on the decrease in Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII) gene expression, and corresponding decreased activity of steroidogenesis genes involved in the synthesis of steroid compounds.  COUP-TFII is also known as also known as Nuclear Receptor Subfamily 2 Group F Member 2 (NR2F2) (Mendoza-Villarroel et al. 2014).

This Key Event Relationship was developed as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki.  Palermo et al. (2021) focused on identifying Adverse Outcome Pathways associated with adverse male reproductive outcomes from phthalate exposure through review of existing literature, and provided initial network analysis.  Authors of KER 3167 did a further evaluation of published peer-reviewed literature to provide additional evidence in support of the key event relationship.

The biological plausibility linking decrease of COUP-TFII gene expression to decreased steroidogenesis is strong.   Predominately in laboratory mammal studies, COUP-TFII gene expression has been studied via toxicant exposure as well as contrasting wild-type strains to strains with decreased COUP-TFII function, and consistently shown decreased steroidogenic activity.

<table cellspacing="0" class="Table" style="border-collapse:collapse"> <tbody> <tr> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:97px"> Species </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:69px"> Duration </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:110px"> Dose </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:89px"> Decreased COUP-TFII? </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:71px"> Decreased Steroidogenic Enzymes? </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:109px"> Summary </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:77px"> Citation </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:97px"> Mouse (Mus musculus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:69px"> 40 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:110px"> Knock-out gene study. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:89px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:71px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:109px"> CD1-mice, various cell lines with wild-type and knock-out gene expression, decreased COUP-IIF (NR2F2) expression decreased the steroidogenic acute regulatory (STAR) gene expression. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:77px"> Mendoza-Villarroel et al. (2014) </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:97px"> Mouse (Mus musculus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:69px"> 3 months </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:110px"> 1 mg/50 g bw tamoxifen for 5 consecutive days in utero, knock-out gene study, juvenile exposure. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:89px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:71px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:109px"> COUP-TFII flox/flox mice and CAGG-Cre-ERTM mice, tamoxifen exposure to inhibit COUP-TFII function, decreased COUP-IIF expression decreased 3β-HSD, 450Scc, and CYP17 gene expression, genes related to steroid biosynthesis. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:77px"> Qin et al. (2008) </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:97px"> Rat (Rattus norvegicus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:69px"> 8 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:110px"> 20, 100, 500 mg/kg/day DBP, 100 ug/kg/day dexamethasone, 100 ug/kg diethylstilbestrol every other day, mixture 500 mg/kg/day DBP plus 100 ug/kg day dexamethasone in utero </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:89px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:71px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:109px"> Wistar rats, dose-dependent response decreased COUP-IIF and decreased STAR, CYP17, CYP11 gene expression, genes related to steroid biosynthesis. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:77px"> van den Driesche et al. (2012) </td> </tr> </tbody> </table>

Moderate Unspecific

Moderate

All life stages

Moderate

Mendoza-Villarroel, R.E., Robert, N.M., Martin, L.J., Brousseau, C., and Tremblay, J.J.  2014.  The Nuclear Receptor NR2F2 Activates Star Expression and Steroidogenesis in Mouse MA-10 and MLTC-1 Leydig Cells.  Biology of Reproduction 91(1) Article 26: 1-12. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Qin, J., Tsai, M.-J., and Tsai S.Y.  2008.  Essential Roles of COUP-TFII in Leydig Cell Differentiation and Male Fertility.  Public Library of Science One 3(9): e3285. van den Driesche, S., Walker, M., McKinnel, C., Scott, HM., Eddie, S.L., Mitchell, R.T., Seckl, J.R., Drake, A.J., Smith, L.B., Anderson, R.A., and Sharpe, R.M.  2012.  Proposed Role for COUP-TFII in Regulating Fetal Leydig Cell Steroidogenesis, Perturbation of Which Leads to Masculinization Disorders in Rodents. Public Library of Science One 7(5): e37064.   NOTE: Italics symbolize edits from John Frisch AOPWiki 2024-03-20T08:44:39

2024-04-16T09:39:41

<upstream-id>4db4c44f-5c70-4208-8372-5a76fc455633</upstream-id> <downstream-id>8bce2a4b-885a-4ecc-b4af-cb00e1754f5e</downstream-id> In this key event relationship we are focused on the decrease in activity of steroidogenesis genes involved in the synthesis of steroid compounds and corresponding decrease in dihydrotestosterone levels.  A large number of genes are involved in regulating steroidogenesis, so here we present evidence from available empirical studies.  Decreased dihydrotestosterone levels are most often noted as resulting from decreases in expression of genes in the StAR, Cyp11, Cyp17, p450, HSD3β, and SR-B1 gene families.

This Key Event Relationship was developed as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki.  Palermo et al. (2021) focused on identifying Adverse Outcome Pathways associated with adverse male reproductive outcomes from phthalate exposure through review of existing literature, and provided initial network analysis.  Authors of KER 3171 did a further evaluation of published peer-reviewed literature to provide additional evidence in support of the key event relationship.

The biological plausibility linking decrease of gene expression associated with steroidogenesis to decreased dihydrotestosterone levels is strong.   Predominately in laboratory mammal studies, gene expression has been studied via toxicant exposure as well as contrasting wild-type strains to strains with knockout gene function, and consistently shown decreased dihydrotestosterone levels.

Moderate Unspecific

Moderate

All life stages

Moderate

Chauvigné, F., Plummer, S., Lesné, L., Cravedi, J.-P., Dejucq-Rainsford, N., Fostier, A., and Jégou, B.  2011.   Mono-(2-ethylhexyl) Phthalate Directly Alters the Expression of Leydig Cell Genes and CYP17 Lyase Activity in Cultured Rat Fetal Testis.  Public Library of Science One 6(11): e27172. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Shi, B. He, E., Chang, K., Xu, G., Meng, Q., Xu, H., Chen, Z., Wang, X., Jia, M., Sun, W., Zhao, W., Zhao, H., Dong, L., and Cui, H.  2024.  Genistein prevents the production of hypospadias induced by Di-(2-ethylhexyl) phthalate through androgen signaling and antioxidant response in rats.  Journal of Hazardous Materials 466: 133537. NOTE: Italics symbolize edits from John Frisch   AOPWiki 2024-03-20T08:49:44

2024-04-11T14:22:53

<upstream-id>8bce2a4b-885a-4ecc-b4af-cb00e1754f5e</upstream-id> <downstream-id>27303c33-8af3-4d59-8e78-65d12da220d3</downstream-id> In this key event relationship we are focused on the decrease in dihydrotestosterone levels and resulting impairment of urethral tube closure.  Decreases in dihydrotestosterone levels can cause a host of developmental issues, but here we present evidence from empirical studies in which induced decreases in dihydrotestosterone result in abnormal urethral tube development.

This Key Event Relationship was developed as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki.  Palermo et al. (2021) focused on identifying Adverse Outcome Pathways associated with adverse male reproductive outcomes from phthalate exposure through review of existing literature, and provided initial network analysis.  Authors of KER 3172 did a further evaluation of published peer-reviewed literature to provide additional evidence in support of the key event relationship.

The biological plausibility linking decreased dihydrotestosterone levels to impairment of urethral tube closure is strong.  Predominately in laboratory mammal studies, dihydrotestosterone levels and resulting histological malformations have been studied via toxicant exposure (especially from phthalates), and shown a consistent response with increased problems with urethral tube malformation.

Moderate Unspecific

High

Development

Moderate

Life Stage: Occurs during development. Sex: Applies to both males and females. Taxonomic: Most representative studies have been done in mammals (humans, lab mice, lab rats); plausible for all vertebrates.

Kim, T.S., Jung, K.K., Kim, S.S., Kang, I.H., Baek, J.H., Nam, H.-S., Hong, S.-K., Lee, B.M., Hong, J.T., Oh, K.W., Kim, H.S., Han, S.Y., and Kang, T.S.  2010.  Effects of in Utero Exposure to DI(n-Butyl) Phthalate on Development of Male Reproductive Tracts in Sprague-Dawley Rats.  Journal of Toxicology and Environmental Health, Part A 73(21-22): 1544-1559. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Shi, B. He, E., Chang, K., Xu, G., Meng, Q., Xu, H., Chen, Z., Wang, X., Jia, M., Sun, W., Zhao, W., Zhao, H., Dong, L., and Cui, H.  2024.  Genistein prevents the production of hypospadias induced by Di-(2-ethylhexyl) phthalate through androgen signaling and antioxidant response in rats.  Journal of Hazardous Materials 466: 133537. Suzuki, H., Suzuki, K., and Yamada, G.  2015.  Systematic analyses of murine masculinization processes based on genital sex differentiation parameters.  Development, Growth, and Differentiation 57: 639–647. NOTE: Italics symbolize edits from John Frisch   AOPWiki 2024-03-20T08:50:02

2024-04-11T16:48:55

<upstream-id>27303c33-8af3-4d59-8e78-65d12da220d3</upstream-id> <downstream-id>f64019d9-dce8-4879-92ff-bfc5fd097a09</downstream-id> In this key event relationship we are focused on the impairment of urethral tube closure and resulting increase in hypospadias.  During development issues arise in organ formation, with resulting impairment observed in mature individuals.

This Key Event Relationship was developed as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki.  Palermo et al. (2021) focused on identifying Adverse Outcome Pathways associated with adverse male reproductive outcomes from phthalate exposure through review of existing literature, and provided initial network analysis.  Authors of KER 3173 did a further evaluation of published peer-reviewed literature to provide additional evidence in support of the key event relationship.

The biological plausibility linking issues with urethral tube formation to increased hypospadias is strong.  Predominately in laboratory mammal studies, malformations from toxicant exposure or genetic damage have resulted in the observed impairment.

<table cellspacing="0" class="Table" style="border-collapse:collapse"> <tbody> <tr> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:78px"> Species </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:63px"> Duration </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:126px"> Dose </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:86px"> Impaired, urethral tube closure? </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px"> Hypospadias? </td> <td style="background-color:#d9d9d9; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px"> Summary </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Rat (Rattus norvegicus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 5 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 75 mg/kg/d linuron, 500 mg/kg/d BBP, or mixture of 75 mg/kg/d linuron and 500 mg/kg/d BBP in utero </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> Sprague-Dawley rats, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Rat (Rattus norvegicus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 40 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 250, 500, 700 mg/kg/d DBP, 1, 12.5, 25 mg/kg/d flutamide in utero, followed through development. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> Sprague-Dawley rats, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Rat (Rattus norvegicus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 8 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 750 mg/kg/d DEHP, mixture treatment with genstein to study moderation of DEHP response in utero </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> Sprague-Dawley rats, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Mouse (Mus musculus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 7 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 100 mg/kg/bw/day tamoxifen in utero, gene knockout study. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> C57BL/6 mice, Mafb mutant mice, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Mouse (Mus musculus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 4 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 100, 200, 300 mg/kg/day finasteride in utero, gene knockout study. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> C57BL/6 mice, Mafb mutant mice, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:78px"> Rat (Rattus norvegicus) </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:63px"> 6 days </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:126px"> 100 mg/kg/day flutamide in utero. </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:86px"> yes   </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px"> yes </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px"> Sprague-Dawley and Wistar rats, increased impairment of urethral tube closure and resulting hypospadias. </td> </tr> </tbody> </table>

High Male

High

During development and at adulthood

Moderate

Hotchkiss, A.K., Parks-Saldutti, L.G., Ostby, J.S., Lambright, C., Furr, J., Vandenbergh, J.G., and Gray, Jr., L.E.  2004.  A Mixture of the ‘‘Antiandrogens’’ Linuron and Butyl Benzyl Phthalate Alters Sexual Differentiation of the Male Rat in a Cumulative Fashion.  Biology of Reproduction 71: 1852–1861. Kim, T.S., Jung, K.K., Kim, S.S., Kang, I.H., Baek, J.H., Nam, H.-S., Hong, S.-K., Lee, B.M., Hong, J.T., Oh, K.W., Kim, H.S., Han, S.Y., and Kang, T.S.  2010.  Effects of in Utero Exposure to DI(n-Butyl) Phthalate on Development of Male Reproductive Tracts in Sprague-Dawley Rats.  Journal of Toxicology and Environmental Health, Part A 73(21-22): 1544-1559. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Shi, B. He, E., Chang, K., Xu, G., Meng, Q., Xu, H., Chen, Z., Wang, X., Jia, M., Sun, W., Zhao, W., Zhao, H., Dong, L., and Cui, H.  2024.  Genistein prevents the production of hypospadias induced by Di-(2-ethylhexyl) phthalate through androgen signaling and antioxidant response in rats.  Journal of Hazardous Materials 466: 133537. Suzuki, K., Numata, T., Suzuki, H., Raga, D.D., Ipulan, L.A., Yokoyama, C., Matsushita, S., Hamada, M., Nakagata, N., Nishinakamura, R., Kume, S., Takahashi, S., and Yamada, G. 2014.  Sexually dimorphic expression of Mafb regulates masculinization of the embryonic urethral formation.  The Proceedings of the National Academy of Sciences  111(46): 16407–16412. Suzuki, H., Suzuki, K., and Yamada, G.  2015.  Systematic analyses of murine masculinization processes based on genital sex differentiation parameters.  Development, Growth, and Differentiation 57: 639–647. Welsh, M., Saunders, P.T.K., Fisken, M., Scott, H.M., Hutchison, G.R., Smith, L.B., and Sharpe, R.M.  2008.  Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism.  The Journal of Clinical Investigation 118(4): 1479–1490. NOTE: Italics symbolize edits from John Frisch   AOPWiki 2024-03-20T08:50:30

2024-04-11T16:44:16

Decreased, Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII) leads to Hypospadias, increased

Decreased COUP-TFII in Leydig cells leads to Hypospadias, increased

Agnes Aggy

Of the originating work: Christine M. Palermo and Jennifer E. Foreman, ExxonMobile; Daniele S. Wikoff, Isabel Lea, ToxStrategies. Of the content populated in the AOP-Wiki:  John R. Frisch and Travis Karschnik, General Dynamics Information Technology; Daniel L. Villeneuve, US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division.

BY-SA

2.6

Hypospadias is an adverse outcome often observed among a group of male reproductive abnormalities caused by organ malformation (epididymis, vas deferens, seminal vesicles, prostate, external genitalia) during development (Drake et al. 2009; Palermo et al. 2021).  These reproductive abnormalities have been observed in studies of laboratory mice and rats exposed to phthalates during in utero development, and clinical studies of humans, in attempts to understand the gene expression/inhibition, hormone levels, and other factors leading to the observed adverse outcomes.  Although a molecular initiating event isn’t well established, decreased Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII)) gene expression has been linked to decreased expression of steroidogenesis hormones and decreased dihydrotestosterone levels in mammals (Chauvigne et al. 2011; Shi et al. 2024).  One adverse outcome of decreased dihydrotestosterone, and the focus of this adverse outcome pathway, is increased hypospadias (Kim et al. 2010; Suzuki et al. 2014; Suzuki et al. 2015).   This Adverse Outcome Pathway (AOP) was developed as part of an Environmental Protection Agency effort to represent putative AOPs from peer-reviewed literature which were heretofore unrepresented in the AOP-Wiki.  The originating work for this AOP was: Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271.  This publication, and the work cited within, were used create and support this AOP and its respective KE and KER pages.  Phthalates are of increasing human health concern because of increased use and accumulating evidence of disruption of reproductive development in vertebrates.  First detected in laboratory mammals, exposure to phthalates and other toxicants in utero when male sexual differentiation is occurring have resulted in increased malformation of reproductive organs, failure of male characteristics to develop, and failure of proper positioning of organs (ex. hypospadias and cryptorchidism).  Clinical studies in humans have used laboratory mammal data to help understand and treat conditions exhibited by individual people.   This AOP focuses on the pathway leading to increased hypospadias, via impaired urethral tube closure, decreased hydrotestosterone levels, and initiated by decreased Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII) gene expression and subsequent disrupted signaling for steroidogenesis. The focus of the originating work was to use an AOP framework to integrate lines of evidence from multiple disciplines based on evolving guidance developed by the Organization for Economic Cooperation and Development (OECD).  Palermo et al. (2021) provided network analysis based on two literature searches: 1. rodent male reproductive development abnormalities using key terms; 2. effects of low molecular weight phthalates (LMWPs) during the rodent male programming window (MPW) of development.  Relevant key events and key event relationships were narrowed by focusing on empirical studies related to ‘rat phthalate syndrome’ which resulted in 3 recommended Adverse Outcome Pathways: 1. INSL expression to cryptorchidism (see AOP 528 for related content); 2. COUP-TFII expression to hypospadias (see this AOP 527 for related content); 3. COUP-TFII expression to altered sperm maturation (see AOP 526 for related content).

The originating authors conducted a literature search to develop a database of publications categorized by discipline or field of study: toxicology, epidemiology, exposure, and gene-environment interaction. The literature search relied on standard search engines such as Web of Science and Google Scholar, and the search strategy focused on toxicants known to disrupt lipid pathways in organisms, and diet studies with elevated levels of lipids. The originating authors reviewed references from individual citations to identify additional studies not captured through the literature search itself. They then included all relevant publications through 2023. Only studies focused primarily on developmental or neurotoxic endpoints were included; those focused on carcinogenesis or other systemic effects were not included unless there was a particular relevance to a neurotoxic or developmental outcome. The scope of the aforementioned EPA project was limited to re-representing the AOP(s) as presented in the originating publication. The literature used to support this AOP and its constituent pages began with the originating publication and followed to the primary, secondary, and tertiary works cited therein. KE and KER page creation and re-use was determined using Handbook principles where page re-use was preferred.   <img alt="" src="https://aopwiki.org/system/dragonfly/production/2024/04/23/7d3mwuiavf_Citation_workflow_graphic.png" />   The authors of AOP 527 also referred to existing AOP-wiki content on disruption of steroidogenesis pathways, especially work by Gary Klinefelter (ex. AOP 70, 71).  We found existing Adverse Outcome Pathway content documented different series of key events then the pathways provided by Palermo et al. (2021), and therefore initiated AOP 527 and updated existing AOP-wiki key events when available.

adjacent

Not Specified

High adjacent

Not Specified

High adjacent

Not Specified

High adjacent

Not Specified

High

High Male

High

During development and at adulthood

Moderate

<table cellspacing="0" class="Table" style="border-collapse:collapse"> <tbody> <tr> <td colspan="2" style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top"> 1. Support for Biological Plausibility of Key Event Relationships: Is there a mechanistic relationship  between KEup and KEdown consistent with established biological knowledge? </td> </tr> <tr> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Key Event Relationship (KER) </td> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Level of Support   Strong = Extensive understanding of the KER based on extensive previous documentation and broad acceptance. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3167: Decreased COUP-TFII in Leydig cells leads to Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  The relationship between decrease in COUP-TFII expression and decreased steroidogenic enzymes (ex. CYP11, CYP17, P450scc, SR-B1, StAR) is broadly accepted and consistently supported across lab mice, lab rats, and clinical human studies. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3168: Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells leads to Decrease, dihydrotestosterone (DHT) level </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  The relationship between decreased steroidogenic enzymes and decreased dihydrotestosterone is broadly accepted and consistently supported across lab mice, lab rats, and clinical human studies. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3172: Decrease, dihydrotestosterone (DHT) level leads to Impaired, urethral tube closure </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Decreased dihydrotestosterone levels have consistently been linked to impaired urethral tube closure and consistently supported across lab mice, lab rats, and clinical human studies. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3173: Impaired, urethral tube closure leads to Hypospadias, increased </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  Impaired urethral tube closure directly leads to hypospadias across lab mice, lab rats, and clinical human studies. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Overall </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  Extensive understanding of the relationships between events from empirical studies from a variety of taxa, including frequent testing in lab mammals. </td> </tr> </tbody> </table> Life Stage: Problems first can be observed during development, with adverse outcome manifesting in mature individuals. Sex: Applies to males. Taxonomic: Appears to be present broadly in mammals, with most representative studies in mammals (humans, lab mice, lab rats).

<table cellspacing="0" class="Table" style="background:white; border-collapse:collapse; width:775px"> <tbody> <tr> <td colspan="2" style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> 2. Essentiality of Key Events: Are downstream KEs and/or the AO prevented if an upstream KE is blocked? </td> </tr> <tr> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Key Event (KE) </td> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Level of Support Strong = Direct evidence from specifically designed experimental studies illustrating essentiality and direct relationship between key events. Moderate = Indirect evidence from experimental studies inferring essentiality of relationship between key events due to difficulty in directly measuring at least one of key events. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> KE 656: Decreased COUP-TFII in Leydig cells </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Moderate support.  Decrease in COUP-TFII expression has been linked to decreased steroidogenic enzymes (ex. CYP11, CYP17, P450scc, SR-B1, StAR).  Evidence is available from toxicant, gene-knockout, and protein studies. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> KE 647 Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  Decreased expression of steroidogenic enzymes (ex. CYP11, CYP17, P450scc, SR-B1, StAR is linked to decreased dihydrotestosterone levels.   Evidence is available from toxicant, gene-knockout, and protein studies. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> KE 1613 Decrease, dihydrotestosterone (DHT) level </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Moderate support.  Decreases in dihydrotestosterone have been correlated with impairment of urethral tube closure.  Evidence is available from toxicant and histology studies. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> KE 2213 Impaired, urethral tube closure </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Improper development and problems with urethral tube closure are linked to hypospadias.  Evidence is available from toxicant and histology studies. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> AO 2082 Hypospadias, increased </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Hypospadias is caused by development issues in formation of reproductive tissues.  Evidence is available from toxicant and histology studies. </td> </tr> <tr> <td style="background-color:white; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Overall </td> <td style="background-color:white; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Moderate to strong support.  Direct evidence from empirical studies from laboratory mammals for most key events, with more inferential evidence for gene expression and protein studies. </td> </tr> </tbody> </table>

<table cellspacing="0" class="Table" style="border-collapse:collapse"> <tbody> <tr> <td colspan="2" style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> 3. Empirical Support for Key Event Relationship: Does empirical evidence support that a  change in KEup leads to an appropriate change in KEdown? </td> </tr> <tr> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Key Event Relationship (KER) </td> <td style="background-color:#d0cece; border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Level of Support  Strong =  Experimental evidence from exposure to toxicant shows consistent change in both events across taxa and study conditions.  </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3167: Decreased COUP-TFII in Leydig cells leads to Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support.  Decreases in COUP-TFII expression lead to decreased steroidogenic enzymes (ex. CYP11, CYP17, P450scc, SR-B1, StAR, primarily from studies examining COUP-TFII knock-out genes, as well as changes in gene expression/protein levels after exposure to chemical stressors. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3168: Decreased steroidogenesis, Decreased Activity of Steroidogenic Enzymes in Adult Leydig cells leads to Decrease, dihydrotestosterone (DHT) level </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Decreases in steroidogenesis enzymes lead to decreases in dihydrotestosterone levels, primarily from studies measuring gene expression and correlation to protein and hormone levels. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3172: Decrease, dihydrotestosterone (DHT) level leads to Impaired, urethral tube closure </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Decreases in dihydrotestosterone have been correlated with impairment of urethral tube closure through measurement of hormone levels, and resulting issues in reproductive tissue formation. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Relationship 3173: Impaired, urethral tube closure leads to Hypospadias, increased </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Malformation of urethral tubes directly results in hypospadias. </td> </tr> <tr> <td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top"> Overall </td> <td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top"> Strong support. Exposure from empirical studies shows consistent change in both events from a variety of taxa, including frequent testing in lab mammals. </td> </tr> </tbody> </table>

<div> <table class="table table-bordered table-fullwidth"> <thead> <tr> <th>Modulating Factor (MF)</th> <th>Influence or Outcome</th> <th>KER(s) involved</th> </tr> </thead> <tbody> <tr> <td> </td> <td> </td> <td> </td> </tr> </tbody> </table> </div>

Chauvigné, F., Plummer, S., Lesné, L., Cravedi, J.-P., Dejucq-Rainsford, N., Fostier, A., and Jégou, B.  2011.   Mono-(2-ethylhexyl) Phthalate Directly Alters the Expression of Leydig Cell Genes and CYP17 Lyase Activity in Cultured Rat Fetal Testis.  Public Library of Science One 6(11): e27172. Drake, A.J., van den Driesche, S., Scott, H.M., Hutchinson, G.R., Seckl, J.R. and Sharpe, R.M.  2009.  Glucocorticoids Amplify Dibutyl Phthalate-Induced Disruption of Testosterone Production and Male Reproductive Development.  Endocrinology 150(11): 5055–5064. Kim, T.S., Jung, K.K., Kim, S.S., Kang, I.H., Baek, J.H., Nam, H.-S., Hong, S.-K., Lee, B.M., Hong, J.T., Oh, K.W., Kim, H.S., Han, S.Y., and Kang, T.S.  2010.  Effects of in Utero Exposure to DI(n-Butyl) Phthalate on Development of Male Reproductive Tracts in Sprague-Dawley Rats.  Journal of Toxicology and Environmental Health, Part A 73(21-22): 1544-1559. Mendoza-Villarroel, R.E., Robert, N.M., Martin, L.J., Brousseau, C., and Tremblay, J.J.  2014.  The Nuclear Receptor NR2F2 Activates Star Expression and Steroidogenesis in Mouse MA-10 and MLTC-1 Leydig Cells.  Biology of Reproduction 91(1) Article 26: 1-12. Palermo, C.M., Foreman, J.E., Wikoff, D.S., and Lea, I.  2021.  Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development.  Current Research in Toxicology 2: 254–271. Shi, B. He, E., Chang, K., Xu, G., Meng, Q., Xu, H., Chen, Z., Wang, X., Jia, M., Sun, W., Zhao, W., Zhao, H., Dong, L., and Cui, H.  2024.  Genistein prevents the production of hypospadias induced by Di-(2-ethylhexyl) phthalate through androgen signaling and antioxidant response in rats.  Journal of Hazardous Materials 466: 133537. Suzuki, K., Numata, T., Suzuki, H., Raga, D.D., Ipulan, L.A., Yokoyama, C., Matsushita, S., Hamada, M., Nakagata, N., Nishinakamura, R., Kume, S., Takahashi, S., and Yamada, G. 2014.  Sexually dimorphic expression of Mafb regulates masculinization of the embryonic urethral formation.  The Proceedings of the National Academy of Sciences  111(46): 16407–16412. Suzuki, H., Suzuki, K., and Yamada, G.  2015.  Systematic analyses of murine masculinization processes based on genital sex differentiation parameters.  Development, Growth, and Differentiation 57: 639–647. AOPWiki 2024-03-19T11:10:58

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