Mouse Gonads Research Articles

Embryological developmental changes in the gonads of male mice associated with lead administration

تتأثر أجهزة جسم الأنسان بدرجات متفاوتة بالتأثير السمّي لمادة الرصاص المنتشرة في البيئة, و تتعرض النساء في سن الأنجاب والحوامل الى خطر التلوث بهذه المادة مؤديا الى ظهور الكثير من حالات العقم كما تتأثر أنسجة وأعضاء الجنين في حالة الحمل مما يؤدي الى حدوث اختلال في النموأو الأجهاض. ونظرا للأستعمال المتزايد للمولدات الكهربائية المعتمدة على الكازولين المدعم بالرصاص كوقود في العراق ولغرض تسليط الضوء على التأثيرات السلبية المحتملة على نتائج الحمل وعلى تطور الأجنة الناتجة عن تلوث البيئة بهذه المادة فقد أجريت هذه الدراسة باستعمال اناث الفئران كنموذج. تهدف الدراسة الى تقييم تاثير استهلاك مادة Lead acetate) ) السامّة من قبل الامهات ولفترات مختلفة من الحمل على التغيرات النمائية للمناسل الذكرية في الاجنة. أجريت هذه الدراسة على 180)) انثى فأر بالغة بعمر ثمانية الى عشرة اسابيع واوزان تتراوح بين 25-27 غرام. قسمت الأناث الى ثلاث مجاميع اختبار رئيسية G1)) و(G2) وG3)) اعتمادا على مقدار الجرعة المعطاة ( 30فأرة/ مجموعة) تقابلها ثلاث مجاميع سيطرة C1 و C2 وC3 (30فأرة/مجموعة) ثم قسمت كل مجموعة رئيسية الى ثلاث مجاميع ثانوية ( 10 فأرة/ مجموعة) على أساس الفترات المختلفة من الحمل التي يتم بعدها قتل الحيوان وهي (اليوم الرابع عشر والسابع عشر واليوم العشرين(. أخذت مسحات مهبلّية لكل الحيوانات يوميّا حتى ظهور طور الشبق لكي يحصل الجماع ويسجّل اليوم الأول للحمل حيث تمت مزاوجة هذه الحيوانات مع ذكور بالغة وحدد حدوث الحمل وحساب اليوم الأول منه من خلال فحص السدّادة المهبليّة. حقنت مجاميع الاختبار G1)) و(G2) وG3)) يوميا ب0.1 و 0.2 و0.4 ملغم /كغم من وزن الجسم على التوالي من محلول أسيتات الرصاص مذابة في المحلول الملحي المتعادل (normal saline) في الخلب لمدة ( 20,17,14 ) يوم من الحمل فيما حقنت مجموعة السيطرةC1 وC2 وC3 بنفس الكميّة و لنفس الفترات بالمحلول الملحي المتعادل فقط. أظهرت النتائج وجود انخفاض معنوي (P<0.05) في كل المعايير التي أخذت للدراسة لمجاميع الأختبارو هي: اوزان أجسام الأمهات و أوزان أرحامها و أعداد وأوزان الأجنة الناميّة مقارنة بمجاميع السيطرة المقابلة. أظهرت الدراسة النسيجيّة في مقاطع المناسل الذكرية لأجنة الأمهات المحقونة زيادة معنوية ( (P<0.05 في معدلات اقطارها في مجموعة اختبار يوم (14 ) مقارنة بمجاميع السيطرة عند الحقن بجرعات واطئة ثم انخفضت وبشكل معنوي جدا (P<0.01) في مجموعتي اختبار 17) و (20 يوم من الحمل مع وجود تغيرات نسجيّة مهمة تضمنت تخريب بنية وتركيب المناسل الذكرية, و انتكاس في الخلايا الجرثومية الأولية مع قلة عددها وتهتك الغشاء القاعدي في كل مجاميع الاختبار. كما لوحظ عدم نزول المناسل إلى موقعها الطبيعي بتقدم العمر حيث بقيت في مكان نشؤها الأولي (قريبا من الكلية) في الجزء العلوي من التجويف ألبطني فيما لوحظ نزولها في حيوانات السيطرة بعمر17 يوم الى قاعدة التجويف البطني ووصلت بعمر20 يوما الى موقع قريب من القناة العجانيّة (لتستقر بموقعها النهائي في كيس الصفن بعد الولادة بوقت قصير ). ان نتائج هذه الدراسة تشيرالى وجود علاقة واضحة بين الحقن بمحلول اسيتات الرصاص وتراجع نتاج الحمل خاصة عند الحقن بجرعة 0.2 و0.4 ملغم /كغم من وزن الجسم حيث سجلّت زيادة معنوية لحالات الاجهاض وموت الأجنة في الرحم. ان النتائج المستخلصة من هذه التجربة تشير الى إن حقن جرعات واطئة من محلول أسيتات الرصاص إثناء فترة الحمل تؤدي إلى حدوث تغيرات نسيجيّة في المناسل الذكريّة للأجنة ومن ثم لابد ان تؤثر على التكاثر عند البلوغ وان التأثير يزداد بزيادة الجرعة المتناولة. إن هذه التأثيرات السلبية تدفعنا لتدارك الخطر الناجم عن استخدام هذه المادة الملوثة وإيجاد الطرق الفعّالة والبديلة للاستخدامات المتوسعة لها من خلال وسائل الأعلام وأجهزة المحافظة على البيئة وعقد الندوات للتعريف بخطر هذه المادة.

Differential changes in end organ immune cells and inflammation in salt-sensitive hypertension: effects of lowering blood pressure.

We reported that salt-sensitive hypertension (SSHTN) is associated with increased pro-inflammatory immune cells, inflammation, and inflammation-associated lymphangiogenesis in the kidneys and gonads of male and female mice. However, it is unknown whether these adverse end organ effects result from increased blood pressure (BP), elevated levels of salt, or both. We hypothesized that pharmaceutically lowering BP would not fully alleviate the renal and gonadal immune cell accumulation, inflammation, and lymphangiogenesis associated with SSHTN. SSHTN was induced in male and female C57BL6/J mice by administering nitro-L-arginine methyl ester hydrochloride (L-NAME; 0.5 mg/ml) in their drinking water for 2 weeks, followed by a 2-week washout period. Subsequently, the mice received a 3-week 4% high salt diet (SSHTN). The treatment group underwent the same SSHTN induction protocol but received hydralazine (HYD; 250 mg/L) in their drinking water during the diet phase (SSHTN+HYD). Control mice received tap water and a standard diet for 7 weeks. In addition to decreasing systolic BP, HYD treatment generally decreased pro-inflammatory immune cells and inflammation in the kidneys and gonads of SSHTN mice. Furthermore, the decrease in BP partially alleviated elevated renal and gonadal lymphatics and improved renal and gonadal function in mice with SSHTN. These data demonstrate that high systemic pressure and salt differentially act on end organ immune cells, contributing to the broader understanding of how BP and salt intake collectively shape immune responses and highlight implications for targeted therapeutic interventions.

Inefficient Sox9 upregulation and absence of Rspo1 repression lead to sex reversal in the B6.XYTIR mouse gonad†.

Sry on the Y-chromosome upregulates Sox9, which in turn upregulates a set of genes such as Fgf9 to initiate testicular differentiation in the XY gonad. In the absence of Sry expression, genes such as Rspo1, Foxl2, and Runx1 support ovarian differentiation in the XX gonad. These two pathways antagonize each other to ensure the development of only one gonadal sex in normal development. In the B6.YTIR mouse, carrying the YTIR-chromosome on the B6 genetic background, Sry is expressed in a comparable manner with that in the B6.XY mouse, yet, only ovaries or ovotestes develop. We asked how testicular and ovarian differentiation pathways interact to determine the gonadal sex in the B6.YTIR mouse. Our results showed that (1) transcript levels of Sox9 were much lower than in B6.XY gonads while those of Rspo1 and Runx1 were as high as B6.XX gonads at 11.5 and 12.5days postcoitum. (2) FOXL2-positive cells appeared in mosaic with SOX9-positive cells at 12.5 days postcoitum. (3) SOX9-positive cells formed testis cords in the central area while those disappeared to leave only FOXL2-positive cells in the poles or the entire area at 13.5 days postcoitum. (4) No difference was found at transcript levels of all genes between the left and right gonads up to 12.5 days postcoitum, although ovotestes developed much more frequently on the left than the right at 13.5 days postcoitum. These results suggest that inefficient Sox9 upregulation and the absence of Rspo1 repression prevent testicular differentiation in the B6.YTIR gonad.

A role for TRPC3 in mammalian testis development.

SOX9 is a key transcription factor for testis determination and development. Mutations in and around the SOX9 gene contribute to Differences/Disorders of Sex Development (DSD). However, a substantial proportion of DSD patients lack a definitive genetic diagnosis. SOX9 target genes are potentially DSD-causative genes, yet only a limited subset of these genes has been investigated during testis development. We hypothesize that SOX9 target genes play an integral role in testis development and could potentially be causative genes in DSD. In this study, we describe a novel testicular target gene of SOX9, Trpc3. Trpc3 exhibits high expression levels in the SOX9-expressing male Sertoli cells compared to female granulosa cells in mouse fetal gonads between embryonic day 11.5 (E11.5) and E13.5. In XY Sox9 knockout gonads, Trpc3 expression is markedly downregulated. Moreover, culture of E11.5 XY mouse gonads with TRPC3 inhibitor Pyr3 resulted in decreased germ cell numbers caused by reduced germ cell proliferation. Trpc3 is also expressed in endothelial cells and Pyr3-treated E11.5 XY mouse gonads showed a loss of the coelomic blood vessel due to increased apoptosis of endothelial cells. In the human testicular cell line NT2/D1, TRPC3 promotes cell proliferation and controls cell morphology, as observed by xCELLigence and HoloMonitor real-time analysis. In summary, our study suggests that SOX9 positively regulates Trpc3 in mouse testes and TRPC3 may mediate SOX9 function during Sertoli, germ and endothelial cell development.

Impacts of the DPP-4 Inhibitor Saxagliptin and SGLT-2 Inhibitor Dapagliflozin on the Gonads of Diabetic Mice.

Diabetes mellitus is a metabolic disease that can cause systemic problems, including testicular dysfunction. Several diabetes medications have demonstrated potential adverse effects on the male reproductive system; however, the effects of saxagliptin and dapagliflozin have not been sufficiently examined. This investigation studied the impacts of saxagliptin and dapagliflozin treatments on the gonads in a male mouse model of diabetes. Testicular disturbances were assessed by sperm DNA damage, diakinesis-metaphase I chromosome examination, and spermiogram analysis. Our results showed more sperm DNA damage, more spermatocyte chromosome aberrations, lower sperm motility/count, and more sperm morphological anomalies in diabetic mice than in the control mice. Dapagliflozin significantly restored all examined measures to the control values in diabetic mice, unlike saxagliptin, which exacerbated the reduction in sperm count and motility. Both drugs significantly restored the gonadal redox imbalances in diabetic mice by decreasing reactive oxygen species accumulation and increasing glutathione levels. In conclusion, our study presents preliminary evidence for the safety and efficacy of dapagliflozin in alleviating testicular abnormalities induced by diabetes, making it a promising candidate drug for patients with diabetes in their reproductive age. As saxagliptin may have negative effects on fertility, its prescription should be avoided in young male diabetic patients.

The effects of pre- and postnatal exposure to perfluorooctanoic acid on the expression of major reproduction-related genes in the mouse hypothalamus and gonads

Perfluorooctanoic acid (PFOA), a ubiquitous environmental pollutant reported to be an endocrine disruptor, is used in many industrial and consumer products. Although the adverse effects of PFOA on the reproductive health of animals and humans have been widely reported, most studies have focused on assessing the anatomical features and conventional histology of adult gonads. Therefore, the molecular mechanisms activated in the hypothalamus and gonads following PFOA exposure during the pre- and postnatal periods are not clear. This study used a mouse model to evaluate the effects of PFOA exposure on the alteration of molecular mechanisms in the hypothalamus and gonads during the prenatal and postpartum periods. Changes in gene and protein expression following PFOA exposure were evaluated by quantitative polymerase chain reaction and Western blotting, respectively. Kisspeptin 1 and gonadotropin-releasing hormone expression in the hypothalamus of female and male mouse pups was significantly decreased. Additionally, Cyp17a1 expression was upregulated in male offspring testes, while Cyp17a1 and Cyp19a1 expression was downregulated in female offspring ovaries. Changes at the molecular level due to PFOA exposure in the early stages of development did not show sex-related differences in the hypothalamus; however, such differences were confirmed in the gonads. These results could be used as basic data to study the molecular mechanisms underlying the reproductive dysfunction caused by PFOA exposure in the early stages of embryonic development.

Comparison of Gonadal Toxicity of Single-Fraction Ultra-High Dose Rate and Conventional Radiation in Mice

PurposeIncreasing evidence suggests that ultra-high-dose-rate (UHDR) radiation could result in similar tumor control as conventional (CONV) radiation therapy (RT) while reducing toxicity to surrounding healthy tissues. Considering that radiation toxicity to gonadal tissues can cause hormone disturbances and infertility in young patients with cancer, the purpose of this study was to assess the possible role of UHDR-RT in reducing toxicity to healthy gonads in mice compared with CONV-RT. Methods and MaterialsRadiation was delivered to the abdomen or pelvis of female (8 or 16 Gy) and male (5 Gy) C57BL/6J mice, respectively, at conventional (∼0.4 Gy/s) or ultrahigh (>100 Gy/s) dose rates using an IntraOp Mobetron linear accelerator. Organ weights along with histopathology and immunostaining of irradiated gonads were used to compare toxicity between radiation modalities. ResultsCONV-RT and UHDR-RT induced a similar decrease in uterine weights at both studied doses (∼50% of controls), which indicated similarly reduced ovarian follicular activity. Histologically, ovaries of CONV- and UHDR-irradiated mice exhibited a comparable lack of follicles. Weights of CONV- and UHDR-irradiated testes were reduced to ∼30% of controls, and the percentage of degenerate seminiferous tubules was also similar between radiation modalities (∼80% above controls). Pairwise comparisons of all quantitative data indicated statistical significance between irradiated (CONV or UHDR) and control groups (from P ≤ .01 to P ≤ .0001) but not between radiation modalities. ConclusionsThe data presented here suggest that the short-term effects of UHDR-RT on the mouse gonads are comparable to those of CONV-RT.

Somatic FGFR2 is Required for Germ Cell Maintenance in the Mouse Ovary.

During sex determination in the mouse, fibroblast growth factor 9 signals through the fibroblast growth factor receptor 2c isoform (FGFR2c) to trigger Sertoli cell and testis development from 11.5 days post coitum (dpc). In the XX gonad, the FOXL2 and WNT4/RSPO1 pathways drive granulosa cell and ovarian development. The function of FGFR2 in the developing ovary, and whether FGFR2 is required in the testis after sex determination, is not clear. In fetal mouse gonads from 12.5 dpc, FGFR2 shows sexually dimorphic expression. In XX gonads, FGFR2c is coexpressed with FOXL2 in pregranulosa cells, whereas XY gonads show FGFR2b expression in germ cells. Deletion of Fgfr2c in XX mice led to a marked decrease/absence of germ cells by 13.5 dpc in the ovary. This indicates that FGFR2c in the somatic pregranulosa cells is required for the maintenance of germ cells. Surprisingly, on the Fgfr2c-/- background, the germ cell phenotype could be rescued by ablation of Foxl2, suggesting a novel mechanism whereby FGFR2 and FOXL2 act antagonistically during germ cell development. Consistent with low/absent FGFR2 expression in the Sertoli cells of 12.5 and 13.5 dpc XY gonads, XY AMH:Cre; Fgfr2flox/flox mice showed normal testis morphology and structures during fetal development and in adulthood. Thus, FGFR2 is not essential for maintaining Sertoli cell fate after sex determination. Combined, these data show that FGFR2 is not necessary for Sertoli cell function after sex determination but does play an important role in the ovary.

The role of steroidogenic factor 1 (SF-1) in steroidogenic cell function of the testes and ovaries of mature mice.

The nuclear receptor steroidogenic factor 1 (SF-1) is essential for mature mouse gonad steroidogenic gene expression, for Leydig and Sertoli cell function, and depletion of SF-1 in steroidogenic cells of the testis compromises steroidogenesis, spermatogenesis and male fertility. Steroidogenic factor 1 (SF-1 or NR5A1) plays an essential role in the development of fetal gonads and regulates genes involved in steroid biosynthesis. Since SF-1 is expressed in multiple cell types in mouse gonads, we developed three novel conditional knockout (cKO) mouse models employing Cre-recombinase and floxed alleles of SF-1 (Nr5a1f/f) to identify its role in testes and ovaries of mature mice: Cytochrome P450 17α-hydroxylase (Cyp17Cre/+;Nr5a1f/f, Leydig and theca cell-specific), aromatase (Cyp19Cre/+;Nr5a1f/f, Sertoli and granulosa cell-specific), as well as a combination of both (Cyp17+Cyp19-Cre;Nr5a1f/f). Compared to control animals, Cyp19-Cre;Nr5a1f/f cKO males showed normal fertility and testicular function. The Cyp17Cre/+;Nr5a1f/f cKO males had smaller testis, with drastically reduced Leydig cell volumes and impaired steroidogenesis, though their reproductive performance remained comparable to controls. Some 50% of Cyp17Cre/++Cyp19Cre/+;Nr5a1f/f double-cKO (dKO) males were infertile, while the remaining 50% showed significantly reduced fertility. These dKO males also had smaller testis with degenerative seminiferous tubules, abnormal Leydig cell morphology and lower levels of intra-testicular testosterone. Abnormal Sertoli cell localization was noted in dKO testes, with increased Sox9, p27 and inhibin subunit ßb and decreased androgen receptor expression. Female mice from all genotypes showed normal reproductive capacity, though steroidogenic gene expression levels were significantly decreased in both Cyp17Cre/+;Nr5a1f/f cKO and dKO females. These results show the essential role of SF-1 in mature mouse gonad steroidogenic gene expression, for Leydig and Sertoli cell function, and that depletion SF-1 in all steroidogenic cells of the testis compromises steroidogenesis, spermatogenesis and male fertility.

Substrain differences in Sry expression at the stage of sex determination in C57BL/6 mouse strains.

The expression of sex determining region of the Y chromosome (Sry) in the fetal gonads is important for male development. In a mouse model of disorders of sex development (C57BL/6 (B6)-XYPOS), the gonadal phenotype and the timing of Sry expression differ due to differences among B6 substrains as the genetic background. Since differences in Sry expression among B6 substrains have been speculated, the present study examined Sry expression in B6J, B6JJmsSlc, and B6NCrl mice. These substrains differed in the number of Sry-expressing cells in the gonads of embryonic mice at each developmental stage, with B6NCrl having more than the other strains. The substrains differed also in the number of Sry-expressing cells between the left and right gonads, with B6J and B6NCrl, but not B6JJmsSlc, showing left gonad-dominant Sry expression. Substrain differences existed also in the distribution of Sry-expressing cells in the medial and lateral directions of gonads. In addition, in the left gonad-dominant Sry-expressing substrains B6J and B6NCrl, the medial and central regions of the left gonad had more Sry-expressing cells than those of the right gonad. Substrains of B6 mice have not always been considered in sex differentiation studies. In the present study, however, we observed substrain differences in the number of Sry-expressing cells, left-right distribution, and medial/lateral distribution during the early stages of gonadal development in B6 mice. Therefore, future studies on sex differentiation in B6 mice should consider substrain differences.

Turnover of mammal sex chromosomes in the Sry-deficient Amami spiny rat is due to male-specific upregulation of Sox9

Mammalian sex chromosomes are highly conserved, and sex is determined by SRY on the Y chromosome. Two exceptional rodent groups in which some species lack a Y chromosome and Sry offer insights into how novel sex genes can arise and replace Sry, leading to sex chromosome turnover. However, intensive study over three decades has failed to reveal the identity of novel sex genes in either of these lineages. We here report our discovery of a male-specific duplication of an enhancer of Sox9 in the Amami spiny rat Tokudaia osimensis, in which males and females have only a single X chromosome (XO/XO) and the Y chromosome and Sry are completely lost. We performed a comprehensive survey to detect sex-specific genomic regions in the spiny rat. Sex-related genomic differences were limited to a male-specific duplication of a 17-kb unit located 430 kb upstream of Sox9 on an autosome. Hi-C analysis using male spiny rat cells showed the duplicated region has potential chromatin interaction with Sox9. The duplicated unit harbored a 1,262-bp element homologous to mouse enhancer 14 (Enh14), a candidate Sox9 enhancer that is functionally redundant in mice. Transgenic reporter mice showed that the spiny rat Enh14 can function as an embryonic testis enhancer in mice. Embryonic gonads of XX mice in which Enh14 was replaced by the duplicated spiny rat Enh14 showed increased Sox9 expression and decreased Foxl2 expression. We propose that male-specific duplication of this Sox9 enhancer substituted for Sry function, defining a novel Y chromosome in the spiny rat.

RETRACTED ARTICLE: Extremely Active Nano-formulation of Resveratrol (XAR™) attenuates and reverses chemotherapy-induced damage in mice ovaries and testes

BackgroundFertility preservation and restoration in cancer patients/survivors is the need of present times when increased numbers of patients get cured of cancer but face infertility as a serious side effect. Resveratrol has beneficial effects on chemoablated ovaries and testes in mice but has failed to enter the clinics because of extremely poor bioavailability. The present study was undertaken to evaluate the protective and curative effects of Extremely active Resveratrol (XAR™)- a nano-formulation of resveratrol with significantly improved bioavailability- on mouse ovary and testis after chemotherapy. Effects of XAR™ and FSH were compared on stimulation of follicle growth in adult mice ovaries. XAR™ (25 mg/kg) was administered for two days prior to chemotherapy to study the protective effects on the mouse gonads. XAR™ was also administered for 14 days post chemoablation to study the regenerative effects. Besides effect on numbers of primordial and growing follicles and spermatogenesis, the effect of XAR™ was also evaluated on the transcripts specific for ovarian/testicular stem/progenitor/germ cells, their proliferation, differentiation, meiosis, and the antioxidant indices.ResultsSimilar to FSH, XAR™ increased the numbers of primordial follicles (PF) as well as growing follicles. It protected the gonads from the adverse effects of chemotherapy and showed the ability to regenerate non-functional, chemoablated gonads. Besides stimulating follicle growth in adult ovaries similar to FSH, XAR™ also protected the testes from the adverse effects of chemotherapy and improved spermatogenesis. This was accompanied by improved anti-oxidant indices.ConclusionsThe results of the present study potentiate the use of XAR™ in pilot clinical studies to protect gonadal function during oncotherapy and also regenerate non-functional gonads in cancer survivors by improving antioxidant indices and stem cell-based tissue regeneration.

Genomics of sexual cell fate transdifferentiation in the mouse gonad.

Sex determination in mammals hinges on a cell fate decision in the fetal bipotential gonad between formation of male Sertoli cells or female granulosa cells. While this decision normally is permanent, loss of key cell fate regulators such as the transcription factors Dmrt1 and Foxl2 can cause postnatal transdifferentiation from Sertoli to granulosa-like (Dmrt1) or vice versa (Foxl2). Here, we examine the mechanism of male-to-female transdifferentiation in mice carrying either a null mutation of Dmrt1 or a point mutation, R111G, that alters the DNA-binding motif and causes human XY gonadal dysgenesis and sex reversal. We first define genes misexpressed during transdifferentiation and then show that female transcriptional regulators driving transdifferentiation in the mutant XY gonad (ESR2, LRH1, FOXL2) bind chromatin sites related to those normally bound in the XX ovary. We next define gene expression changes and abnormal chromatin compartments at the onset of transdifferentiation that may help destabilize cell fate and initiate the transdifferentiation process. We model the R111G mutation in mice and show that it causes dominant gonadal dysgenesis, analogous to its human phenotype but less severe. We show that R111G partially feminizes the testicular transcriptome and causes dominant disruption of DMRT1 binding specificity in vivo. These data help illuminate how transdifferentiation occurs when sexual cell fate maintenance is disrupted and identify chromatin sites and transcripts that may play key roles in the transdifferentiation process.

The Central Domain of MCPH1 Controls Development of the Cerebral Cortex and Gonads in Mice.

MCPH1 is the first gene identified to be responsible for the human autosomal recessive disorder primary microcephaly (MCPH). Mutations in the N-terminal and central domains of MCPH1 are strongly associated with microcephaly in human patients. A recent study showed that the central domain of MCPH1, which is mainly encoded by exon 8, interacts with E3 ligase βTrCP2 and regulates the G2/M transition of the cell cycle. In order to investigate the biological functions of MCPH1’s central domain, we constructed a mouse model that lacked the central domain of MCPH1 by deleting its exon 8 (designated as Mcph1-Δe8). Mcph1-Δe8 mice exhibited a reduced brain size and thinner cortex, likely caused by a compromised self-renewal capacity and premature differentiation of Mcph1-Δe8 neuroprogenitors during corticogenesis. Furthermore, Mcph1-Δe8 mice were sterile because of a loss of germ cells in the testis and ovary. The embryonic fibroblasts of Mcph1-Δe8 mice exhibited premature chromosome condensation (PCC). All of these findings indicate that Mcph1-Δe8 mice are reminiscent of MCPH1 complete knockout mice and Mcph1-ΔBR1 mice. Our study demonstrates that the central domain of MCPH1 represses microcephaly, and is essential for gonad development in mammals.

Hypertension induces gonadal macrophage imbalance, inflammation, lymphangiogenesis, and dysfunction.

Hypertension (HTN) is associated with gonadal dysfunction and impaired reproductive health in both men and women. An imbalance in the systemic and renal proinflammatory (M1)/anti-inflammatory (M2) macrophage ratio, increased inflammation, and inflammation-associated lymphangiogenesis have been observed in animals with HTN. However, the impact of HTN on gonadal macrophages, inflammation, and lymphatics remains obscure. We hypothesized that salt-sensitive HTN (SSHTN) and HTN alters gonadal macrophage polarization, which is associated with inflammation, inflammation-associated lymphangiogenesis, and reproductive dysfunction. Flow cytometry analyses revealed a significant increase in M1 macrophages in the testes of SSHTN and nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced HTN (LHTN) mice, with a concurrent decrease in M2 macrophages in SSHTN mice yet an increase in M2 macrophages in LHTN mice. Ovaries from SSHTN mice exhibited an increase in M1 and a decrease in M2 macrophages, while ovaries from LHTN mice had a significant increase in M2 and a decrease in M1 macrophages. Gene expression patterns of proinflammatory cytokines revealed gonadal inflammation in all hypertensive mice. Increased lymphatic vessel density in the gonads of both male and female hypertensive mice was confirmed by immunofluorescence staining for lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). HTN adversely affected the expression pattern of steroidogenic enzymes, hormone receptors, and secretory proteins in both the testes and ovaries. In line with these results, male hypertensive mice also presented with decreased sperm concentration, and increased percentage of sperm with abnormal morphology, damaged acrosome, and nonfunctional mitochondrial activity. These data demonstrate that HTN alters gonadal macrophage polarization, which is associated with gonadal inflammation, inflammation-associated lymphangiogenesis, and dysfunction.

Deciphering Sex-Specific Differentiation of Human Fetal Gonads: Insight From Experimental Models.

Sex-specific gonadal differentiation is initiated by the expression of SRY in male foetuses. This promotes a signalling pathway directing testicular development, while in female foetuses the absence of SRY and expression of pro-ovarian factors promote ovarian development. Importantly, in addition to the initiation of a sex-specific signalling cascade the opposite pathway is simultaneously inhibited. The somatic cell populations within the gonads dictates this differentiation as well as the development of secondary sex characteristics via secretion of endocrine factors and steroid hormones. Opposing pathways SOX9/FGF9 (testis) and WNT4/RSPO1 (ovary) controls the development and differentiation of the bipotential mouse gonad and even though sex-specific gonadal differentiation is largely considered to be conserved between mice and humans, recent studies have identified several differences. Hence, the signalling pathways promoting early mouse gonad differentiation cannot be directly transferred to human development thus highlighting the importance of also examining this signalling in human fetal gonads. This review focus on the current understanding of regulatory mechanisms governing human gonadal sex differentiation by combining knowledge of these processes from studies in mice, information from patients with differences of sex development and insight from manipulation of selected signalling pathways in ex vivo culture models of human fetal gonads.

Origin, specification and differentiation of a rare supporting-like lineage in the developing mouse gonad.

Gonadal sex determination represents a unique model for studying cell fate decisions. However, a complete understanding of the different cell lineages forming the developing testis and ovary remains elusive. Here, we investigated the origin, specification, and subsequent sex-specific differentiation of a previously uncharacterized population of supporting-like cells (SLCs) in the developing mouse gonads. The SLC lineage is closely related to the coelomic epithelium and specified as early as E10.5, making it the first somatic lineage to be specified in the bipotential gonad. SLC progenitors are localized within the genital ridge at the interface with the mesonephros and initially coexpress Wnt4 and Sox9. SLCs become sexually dimorphic around E12.5, progressively acquire a more Sertoli- or pregranulosa-like identity and contribute to the formation of the rete testis and rete ovarii. Last, we found that WNT4 is a crucial regulator of the SLC lineage and is required for normal development of the rete testis.

Desmoplakin (Dsp) conditional knockout in NR5A1+ somatic cells affects germ cell survival in developing mouse gonads.

Cell to cell interactions are crucial for morphogenesis and tissue formation. Desmoplakin (encoded by the Dsp gene) is a component of desmosomes and anchors the transmembrane adhesion proteins to the cytoskeleton. Its role in gonad development remains vague. To study the role of desmoplakin in gonad development, we used a tissue-specific knockout of the Dsp gene in the NR5A1+ somatic cells of the gonads. We show here that desmoplakin is necessary for the survival of germ cells in fetal testes and ovaries. The Dspknockout in NR5A1+ somatic cells in testes decreased the number of germ cells, and thus the size of the testes, but did not affect the Sertoli cells or the structure of testis cords and interstitium. The Dspknockout in NR5A1+ somatic cells in ovaries decreased the number of female germ cells and drastically reduced the formation of ovarian follicles. Dsp knockout in NR5A1+ somatic cells did not affect the sex determination and sexual differentiation of the gonads, as judged from an unchanged expression of genes essential for these processes. We conclude that mediation by desmoplakin cell adhesion between the gonadal cells is necessary for germ cell survival.

Lhx2 in germ cells suppresses endothelial cell migration in the developing ovary

LIM-homeobox genes play multiple roles in developmental processes, but their roles in gonad development are not completely understood. Herein, we report that Lhx2, Ils2, Lmx1a, and Lmx1b are expressed in a sexually dimorphic manner in mouse, rat, and human gonads during sex determination. Amongst these, Lhx2 has female biased expression in the developing gonads of species with environmental and genetic modes of sex determination. Single-cell RNAseq analysis revealed that Lhx2 is exclusively expressed in the germ cells of the developing mouse ovaries. To elucidate the roles of Lhx2 in the germ cells, we analyzed the phenotypes of Lhx2 knockout XX gonads. While the gonads developed appropriately in Lhx2 knockout mice and the somatic cells were correctly specified in the developing ovaries, transcriptome analysis revealed enrichment of genes in the angiogenesis pathway. There was an elevated expression of several pro-angiogenic factors in the Lhx2 knockout ovaries. The elevated expression of pro-angiogenic factors was associated with an increase in numbers of endothelial cells in the Lhx2−/− ovaries at E13.5. Gonad recombination assays revealed that the increased numbers of endothelial cells in the XX gonads in absence of Lhx2 was due to ectopic migration of endothelial cells in a cell non-autonomous manner. We also found that, there was increased expression of several endothelial cell-enriched male-biased genes in Lhx2 knockout ovaries. Also, in absence of Lhx2, the migrated endothelial cells formed an angiogenic network similar to that of the wild type testis, although the coelomic blood vessel did not form. Together, our results suggest that Lhx2 in the germ cells is required to suppress vascularization in the developing ovary. These results suggest a need to explore the roles of germ cells in the control of vascularization in developing gonads. Preprint version of the article is available on BioRxiv at https://doi.org/10.1101/2022.03.07.483280.

The functions of Wt1 in mouse gonad development and somatic cells differentiation†.

Wilms' tumor 1 (Wt1) encodes a zinc finger nuclear transcription factor which is mutated in 15-20% of Wilms' tumor, a pediatric kidney tumor. Wt1 has been found to be involved in the development of many organs. In gonads, Wt1 is expressed in genital ridge somatic cells before sex determination, and its expression is maintained in Sertoli cells and granulosa cells after sex determination. It has been demonstrated that Wt1 is required for the survival of the genital ridge cells. Homozygous mutation of Wt1 causes gonad agenesis. Recent studies find that Wt1 plays important roles in lineage specification and maintenance of gonad somatic cells. In this review, we will summarize the recent research works about Wt1 in gonadal somatic cell differentiation.