19 results on '"Liu, Yi-xun"'
Search Results
2. Requirement for CCNB1 in mouse spermatogenesis.
- Author
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Tang JX, Li J, Cheng JM, Hu B, Sun TC, Li XY, Batool A, Wang ZP, Wang XX, Deng SL, Zhang Y, Chen SR, Huang X, and Liu YX
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- Animals, Cell Differentiation, Cyclin B1 deficiency, Cyclin B1 genetics, Cyclin B1 metabolism, Male, Mice, Mice, Knockout, Cyclin B1 physiology, Spermatogenesis physiology
- Abstract
Spermatogenesis, which involves mitosis and meiosis of male germ cells, is a highly complicated and coordinately ordered process. Cyclin B1 (CCNB1), an important regulator in cell cycle machinery, is proved essential for mouse embryonic development. However, the role of CCNB1 in mammalian spermatogenesis remains unclear. Here we tested the requirement for CCNB1 using conditional knockout mice lacking CCNB1 in male germ cells. We found that ablation of CCNB1 in gonocytes and spermatogonia led to mouse sterile caused by the male germ cells' depletion. Gonocyte and spermatogonia without CCNB1 is unable to proliferate normally and apoptosis increased. Moreover, CCNB1 ablation in spermatogonia may promote their differentiation by downregulating Lin28a and upregulating let-7 miRNA. However, ablation of CCNB1 in premeiotic male germ cells did not have an effect on meiosis of spermatocytes and male fertility, suggesting that CCNB1 may be dispensable for meiosis of spermatocytes. Collectively, these results indicate that CCNB1 is critically required for the proliferation of gonocytes and spermatogonia but may be redundant in meiosis of spermatocytes in mouse spermatogenesis.
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- 2017
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3. Selective deletion of Smad4 in postnatal germ cells does not affect spermatogenesis or fertility in mice.
- Author
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Hao XX, Chen SR, Tang JX, Li J, Cheng JM, Jin C, Wang XX, and Liu YX
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- Animals, Gene Deletion, Male, Mice, Mice, Transgenic, Smad4 Protein genetics, Fertility physiology, Smad4 Protein metabolism, Spermatogenesis physiology, Testis growth & development
- Abstract
SMAD4 is the central component of canonical signaling in the transforming growth factor beta (TGFβ) superfamily. Loss of Smad4 in Sertoli cells affects the expansion of the fetal testis cords, whereas selective deletion of Smad4 in Leydig cells alone does not appreciably alter fetal or adult testis development. Loss of Smad4 in Sertoli and Leydig cells, on the other hand, leads to testicular dysgenesis, and tumor formation in mice. Within the murine testes, Smad4 is also expressed in germ cells of the seminiferous tubules. We therefore, crossed Ngn3-Cre or Stra8-Cre transgenic mice with Smad4-flox mice to generate conditional knockout animals in which Smad4 was specifically deleted in postnatal germ cells to further uncover cell type-specific requirement of Smad4. Unexpectedly, these germ-cell-knockout mice were fertile and did not exhibit any detectable abnormalities in spermatogenesis, indicating that Smad4 is not required for the production of sperm; instead, these data indicate a cell type-specific requirement of Smad4 primarily during testis development. Mol. Reprod. Dev. 83: 615-623, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
- Published
- 2016
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4. Melatonin promotes development of haploid germ cells from early developing spermatogenic cells of Suffolk sheep under in vitro condition.
- Author
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Deng SL, Chen SR, Wang ZP, Zhang Y, Tang JX, Li J, Wang XX, Cheng JM, Jin C, Li XY, Zhang BL, Yu K, Lian ZX, Liu GS, and Liu YX
- Subjects
- Animals, Blotting, Western, Cells, Cultured, Female, Flow Cytometry, Immunohistochemistry, In Vitro Techniques, Male, Real-Time Polymerase Chain Reaction, Sheep, Sperm Injections, Intracytoplasmic drug effects, Stem Cells cytology, Stem Cells drug effects, Antioxidants pharmacology, Cell Differentiation drug effects, Melatonin pharmacology, Spermatogenesis drug effects, Spermatozoa cytology, Spermatozoa drug effects
- Abstract
Promotion of spermatogonial stem cell (SSC) differentiation into functional sperms under in vitro conditions is a great challenge for reproductive physiologists. In this study, we observed that melatonin (10(-7) M) supplementation significantly enhanced the cultured SSCs differentiation into haploid germ cells. This was confirmed by the expression of sperm special protein, acrosin. The rate of SSCs differentiation into sperm with melatonin supplementation was 11.85 ± 0.93% which was twofold higher than that in the control. The level of testosterone, the transcriptions of luteinizing hormone receptor (LHR), and the steroidogenic acute regulatory protein (StAR) were upregulated with melatonin treatment. At the early stage of SSCs culture, melatonin suppressed the level of cAMP, while at the later stage, it promoted cAMP production. The similar pattern was observed in testosterone content. Expressions for marker genes of meiosis anaphase, Dnmt3a, and Bcl-2 were upregulated by melatonin. In contrast, Bax expression was downregulated. Importantly, the in vitro-generated sperms were functional and they were capable to fertilize oocytes. These fertilized oocytes have successfully developed to the blastula stage., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)
- Published
- 2016
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5. Regulation of spermatogonial stem cell self-renewal and spermatocyte meiosis by Sertoli cell signaling.
- Author
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Chen SR and Liu YX
- Subjects
- Humans, Male, Sertoli Cells cytology, Signal Transduction, Spermatocytes cytology, Spermatogonia metabolism, Stem Cells metabolism, Meiosis physiology, Sertoli Cells physiology, Spermatocytes physiology, Spermatogenesis physiology, Spermatogonia cytology, Stem Cells cytology
- Abstract
Spermatogenesis is a continuous and productive process supported by the self-renewal and differentiation of spermatogonial stem cells (SSCs), which arise from undifferentiated precursors known as gonocytes and are strictly controlled in a special 'niche' microenvironment in the seminiferous tubules. Sertoli cells, the only somatic cell type in the tubules, directly interact with SSCs to control their proliferation and differentiation through the secretion of specific factors. Spermatocyte meiosis is another key step of spermatogenesis, which is regulated by Sertoli cells on the luminal side of the blood-testis barrier through paracrine signaling. In this review, we mainly focus on the role of Sertoli cells in the regulation of SSC self-renewal and spermatocyte meiosis, with particular emphasis on paracrine and endocrine-mediated signaling pathways. Sertoli cell growth factors, such as glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor 2 (FGF2), as well as Sertoli cell transcription factors, such as ETS variant 5 (ERM; also known as ETV5), nociceptin, neuregulin 1 (NRG1), and androgen receptor (AR), have been identified as the most important upstream factors that regulate SSC self-renewal and spermatocyte meiosis. Other transcription factors and signaling pathways (GDNF-RET-GFRA1 signaling, FGF2-MAP2K1 signaling, CXCL12-CXCR4 signaling, CCL9-CCR1 signaling, FSH-nociceptin/OPRL1, retinoic acid/FSH-NRG/ERBB4, and AR/RB-ARID4A/ARID4B) are also addressed., (© 2015 Society for Reproduction and Fertility.)
- Published
- 2015
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6. Wt1 deficiency causes undifferentiated spermatogonia accumulation and meiotic progression disruption in neonatal mice.
- Author
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Zheng QS, Wang XN, Wen Q, Zhang Y, Chen SR, Zhang J, Li XX, Sha RN, Hu ZY, Gao F, and Liu YX
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- Animals, Claudins genetics, Claudins metabolism, Male, Mice, Mice, Knockout, WT1 Proteins genetics, Meiosis physiology, Sertoli Cells metabolism, Spermatogenesis physiology, Spermatogonia metabolism, WT1 Proteins metabolism
- Abstract
Spermatogenesis is a complex process involving the regulation of multiple cell types. As the only somatic cell type in the seminiferous tubules, Sertoli cells are essential for spermatogenesis throughout the spermatogenic cycle. The Wilms tumor gene, Wt1, is specifically expressed in the Sertoli cells of the mouse testes. In this study, we demonstrated that Wt1 is required for germ cell differentiation in the developing mouse testes. At 10 days post partum, Wt1-deficient testes exhibited clear meiotic arrest and undifferentiated spermatogonia accumulation in the seminiferous tubules. In addition, the expression of claudin11, a marker and indispensable component of Sertoli cell integrity, was impaired in Wt1(-/flox); Cre-ER(TM) testes. This observation was confirmed in in vitro testis cultures. However, the basal membrane of the seminiferous tubules in Wt1-deficient testes was not affected. Based on these findings, we propose that Sertoli cells' status is affected in Wt1-deficient mice, resulting in spermatogenesis failure.
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- 2013
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7. Temperature control of spermatogenesis and prospect of male contraception.
- Author
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Liu YX
- Subjects
- Animals, Apoptosis physiology, Germ Cells metabolism, Gossypol pharmacology, Haplorhini, Humans, Male, Rats, Testosterone pharmacology, Contraception methods, Contraceptive Agents, Male pharmacology, Gene Expression Regulation physiology, Germ Cells physiology, Sertoli Cells physiology, Spermatogenesis physiology, Temperature
- Abstract
Artificial cryptorchidism or local testicular heat treatment could induce reversible oligospermia or azoospermia in monkeys via germ cell apoptosis. A single exposure of rat or monkey testes at 43 degrees centigrade resulted in selective and reversible damage to seminiferous epithelium. Local warming monkey testes at 43 degrees centigrade water for consecutive two days (30 minutes per day) showed that the sperm amount in the semen decreased up to 80% at 28 days and is completely reversible. Furthermore, the heat treatment in combination with testosterone, the sperm account reduced to zero in 2 month time. Withdrawing the testosterone implant, the density of semen sperms recovered to the normal levels after 2-3 months. Apoptosis induced by testosterone occurs mainly at stages 7-8, while testicular "heat stress" induces germ cell apoptosis mostly at stages 1- 4 and 10-12, an additive reversible germ cell apoptosis could be achieved. These findings have provided an important theoretical basis for designing combined male contraceptives. This present review summarized progress on the mechanism of heat-induced germ cell apoptosis.
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- 2010
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8. Male germ cell-specific protein Trs4 binds to multiple proteins.
- Author
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Shi YQ, Li YC, Hu XQ, Liu T, Liao SY, Guo J, Huang L, Hu ZY, Tang AY, Lee KF, Yeung WS, Han CS, and Liu YX
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- Amino Acid Sequence, Animals, Carrier Proteins genetics, Cloning, Molecular, Humans, Male, Mice, Molecular Sequence Data, Proteins genetics, Proteins metabolism, RNA, Messenger biosynthesis, Rats, Rats, Sprague-Dawley, Transduction, Genetic, Carrier Proteins metabolism, Spermatogenesis, Spermatozoa metabolism, Testis metabolism
- Abstract
Temperature-related sequence 4 (Trs4) has been identified as a testis-specific gene with expression sensitive to the abdominal temperature changes induced by artificial cryptorchidism. In murine testes, Trs4 mRNA was detected in round spermatids and its protein was localized mainly in the elongating spermatids as well as in the acrosomes and tails of mature spermatozoa. Using a yeast two-hybrid screening system, we identified Rshl-2, Gstmu1, and Ddc8 as putative binding partners of the Trs4 protein in mouse testes. Their interactions were confirmed by in vivo and in vitro binding assays. Further studies demonstrated that Ddc8, a newly identified gene with unknown functions, displayed a similar expression pattern with Trs4 in mouse testes. In particular, Trs4, Ddc8, and Rshl-2 proteins were co-localized to the tails of mature spermatozoa. These results suggested that Trs4 might be involved in diverse processes of spermiogenesis and/or fertilization through interactions with its multiple binding partners.
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- 2009
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9. Involvement of plasminogen activator and plasminogen activator inhibitor type 1 in spermatogenesis, sperm capacitation, and fertilization.
- Author
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Liu YX
- Subjects
- Animals, Female, Humans, Male, Spermatozoa ultrastructure, Acrosome Reaction physiology, Plasminogen Activator Inhibitor 1 metabolism, Plasminogen Activators metabolism, Sperm Capacitation physiology, Spermatogenesis physiology, Spermatozoa metabolism
- Abstract
Increasing evidence suggests that local fibrinolysis generated by plasminogen activator (PA) and modulated by plasminogen activator inhibitor type 1 (PAI-1) is essential for mammalian spermatogenesis, sperm capacitation, and fertilization. Tissue-type PA (t-PA), urokinase-type PA (u-PA), and PAI-1 have been reported in the testes of various animals. Sertoli cells within the seminiferous epithelium are believed to play a central role in the control and maintenance of spermatogenesis by producing regulatory factors, including PA/PAI-1. Fertilization is a unique and exquisitely choreographed cellular interaction between male and female gametes, in which some basic biochemical mechanisms remain unresolved. A key issue is the molecular basis of sperm-egg recognition, binding, and penetration. Sperm capacitation and the acrosomal reaction appear to rely on local fibrinolysis generated by the PA/PAI-1 system. Ejaculated spermatozoa from various species carry u-PA activity. The u-PA receptor (uPAR) and the inhibitor PAI-1 have also been reported to bind on the sperm membrane surface. Thus, it is possible that uPAR and PAI-1 function in a counterbalanced and coordinated way on the surface of spermatozoa to regulate the u-PA binding capacity. This review summarizes evidence for the involvement of PA/PAI-1 system in spermatogenesis, sperm capacitation, and fertilization.
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- 2007
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10. Afaf, a novel vesicle membrane protein, is related to acrosome formation in murine testis.
- Author
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Li YC, Hu XQ, Zhang KY, Guo J, Hu ZY, Tao SX, Xiao LJ, Wang QZ, Han CS, and Liu YX
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- 3T3 Cells, Animals, Autoantigens genetics, Autoantigens metabolism, Cell Membrane genetics, Endosomes genetics, Endosomes metabolism, Gene Expression Regulation physiology, HeLa Cells, Humans, Male, Membrane Proteins genetics, Membrane Proteins metabolism, Mice, Rats, Rats, Sprague-Dawley, Spermatids cytology, Testis cytology, Vesicular Transport Proteins, Acrosome metabolism, Cell Membrane metabolism, Membrane Proteins biosynthesis, Spermatids metabolism, Spermatogenesis physiology, Testis metabolism
- Abstract
As a cell-specific organelle, acrosome (Acr) and its formation are an important event for spermiogenesis. However, the Acr formation is far more complicated than has been proposed. In this study, we have cloned a novel membrane protein Afaf (Acr formation associated factor) that was expressed abundantly in the round spermatids, localized in the inner and outer membrane of forming Acrs, and declined in the maturing Acrs. In the transfected Hela cells, Afaf protein was localized in the plasma membrane, EEA1-positive early endosomes (EEs) and occasionally in the nuclei. Therefore, we propose that EEs and plasma membrane may be also directly involved in the Acr biogenesis.
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- 2006
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11. Transient testicular warming enhances the suppressive effect of testosterone on spermatogenesis in adult cynomolgus monkeys (Macaca fascicularis).
- Author
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Lue Y, Wang C, Liu YX, Hikim AP, Zhang XS, Ng CM, Hu ZY, Li YC, Leung A, and Swerdloff RS
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- Animals, Apoptosis physiology, Biopsy veterinary, Germ Cells physiology, Histocytochemistry veterinary, In Situ Nick-End Labeling, Male, Random Allocation, Sperm Count veterinary, Spermatogenesis physiology, Testosterone blood, Hyperthermia, Induced veterinary, Macaca fascicularis physiology, Spermatogenesis drug effects, Testis drug effects, Testis physiology, Testosterone administration & dosage
- Abstract
Context: The context of the study was to examine whether combined testosterone (T) and heat (H) treatment have additive or synergistic effects on suppression of spermatogenesis., Objective: The objective of the study was to determine whether T+H induces a greater suppression of spermatogenesis than either treatment alone in monkeys., Design: The study was a randomized, placebo-controlled study., Setting: The study was conducted at a primate center in China., Participants: The study population was comprised of 32 adult cynomolgus monkeys., Interventions: Groups of eight adult monkeys were treated for 12 wk with: 1) two empty implants (C); 2) two T implants (T); 3) daily testicular heat exposure (43 C for 30 min) for 2 consecutive days (H); or 4) two T implants plus testicular heat exposure (T+H). Treatment was followed by an 8-wk recovery period., Main Outcome Measures: Measures included sperm counts and germ cell apoptosis., Results: Serum T levels were elevated in both the T and T+H groups during treatment but not in the C or H group. Sperm counts were transiently suppressed after heat to 16.4% of baseline at 4 wk and then returned to pretreatment levels. Sperm counts were suppressed slowly after T treatment to nadir of 6.4% of pretreatment levels at 12 wk. T+H rapidly suppressed sperm output as early as 4 wk to 3.9% of pretreatment levels that was maintained throughout treatment. The decreased sperm counts were due to increased germ cell apoptosis in all treatment groups. Sperm counts recovered to the pretreatment levels in all groups by 8 wk after treatment., Conclusion: This proof-of-concept study demonstrates that transient testicular warming enhances and hastens the effect of T implant on the suppression of spermatogenesis in monkeys.
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- 2006
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12. Cloning and characterization of a novel spermiogenesis-related gene, T6441, in rat testis.
- Author
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Song XX, Li YC, Shi YQ, Hu XQ, Hu ZY, Han CS, and Liu YX
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- Amino Acid Sequence, Animals, Blotting, Northern, Blotting, Western, Cloning, Molecular, Cytoplasm metabolism, DNA, Complementary metabolism, Fluorescent Antibody Technique, Indirect, Gene Expression Regulation, Gene Library, Green Fluorescent Proteins metabolism, HeLa Cells, Humans, Immunohistochemistry, In Situ Hybridization, Male, Molecular Sequence Data, Nucleic Acid Hybridization, RNA, Messenger metabolism, Rats, Receptors, Laminin biosynthesis, Recombinant Proteins chemistry, Reverse Transcriptase Polymerase Chain Reaction, Ribosomal Proteins biosynthesis, Sequence Homology, Amino Acid, Spermatids metabolism, Time Factors, Tissue Distribution, Receptors, Laminin chemistry, Receptors, Laminin genetics, Ribosomal Proteins chemistry, Ribosomal Proteins genetics, Spermatogenesis, Testis metabolism
- Abstract
We report in the present study the cloning and characterization of a novel gene, named T6441, initially derived by the suppressive subtracted hybridization (SSH) cDNA library. The full-length T6441cDNA was 664 bp long, containing a complete open-reading frame for a protein of 149 amino acids (aa). The protein bears no homology to any reported genes. It is predicted that the molecular mass was about 16.7 kDa. Northern blot analysis showed that the T6441 gene had about 4 transcripts in adult rat testis and was temporally regulated in a stage-dependent manner in the testis. In situ hybridization showed that T6441 mRNA was specifically localized in spermatids, and its expression level varied in the cells at different stages of the testicular development, with the highest level at steps 7-14. RT-PCR results showed that the T6441 mRNA was transcribed in most of the tested tissues with its strongest signal in the testis. Recombinant T6441 protein was prepared, purified, and was used to raise rabbit. Western blot analysis using the antiserum revealed four possible testicular specific proteins with their molecular weights being about 22, 25, 50 and 55 kDa respectively. The T6441 protein was expressed mainly in the cytoplasm of spermatids with the maximal levels at steps 12-19. At step 19 spermatid, the T6441 was mainly localized in the residual bodies. The cytoplasm localization of T6441 protein was supported by transient over expression of GFP-fusion protein in Hela cells. Interestingly, the expression of T6441 caused death of transfected cells within 48 h. Our preliminary experimental results suggest that the T6441 gene may play a role in cytoplasm movement and removal during spermiogenesis.
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- 2006
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13. Control of spermatogenesis in primate and prospect of male contraception.
- Author
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Liu YX
- Subjects
- Animals, Follicle Stimulating Hormone genetics, Follicle Stimulating Hormone metabolism, Follicle Stimulating Hormone physiology, Luteinizing Hormone genetics, Luteinizing Hormone metabolism, Luteinizing Hormone physiology, Male, Contraceptive Agents, Male, Gossypol, Primates physiology, Spermatogenesis
- Abstract
The present review is a summary of mechanisms of spermatogenesis in primates with emphasis on anti-spermatogenesis of testosterone (T), gossypol, and "testicular heat stress" for development of male contraception, Both FSH and testosterone stimulate all phases of spermatogenesis. FSH is capable of amplifying the population of the differential spermatogonia (B1, B2, B3 and B4) and controls the spermatogonia production rate, and, in synergy with testosterone, regulating spermatogenesis in adult monkeys. Pituitary FSH beta gene expression is governed by a feedback of Beta inhibin, which is a major component of the testicular negative feedback signals. Beta inhibin secreted by Sertoli cells is in turn inhibited by testosterone from Leydig cells under the control of LH. Disturbance of the normal interaction of pituitary FSH with Sertoli cell Beta inhibin is responsible for azoospermia or oligozoospermia induced by exogenous T. Three possible regimens of T, gossypol and "heat stress" have been suggested for male contraception. They act on different sites and stages of spermatogenesis in testis or sperm activity in epididymis. Apoptosis induced by testosterone occurs mainly at staged VII-VIII of spermatogenesis while that by testicular "heat stress" mostly occurs at stages I-IV and X-XII. Low dose of gossypol mainly influences the sperm activity in the epididymis although it also acts on testicular spermatids.
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- 2005
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14. Testicular germ cell tumor: a comprehensive review
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Batool, Aalia, Karimi, Najmeh, Wu, Xiang-Nan, Chen, Su-Ren, and Liu, Yi-Xun
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- 2019
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15. Melatonin Ameliorates Inflammation and Oxidative Stress by Suppressing the p38MAPK Signaling Pathway in LPS-Induced Sheep Orchitis.
- Author
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Deng, Shou-Long, Zhang, Bao-Lu, Reiter, Russel J., and Liu, Yi-Xun
- Subjects
ORCHITIS ,NF-kappa B ,GRAM-negative bacterial diseases ,OXIDATIVE stress ,MELATONIN ,BACTERIAL cell walls ,SPERMATOGENESIS - Abstract
Gram-negative bacterial infections of the testis can lead to infectious orchitis, which negatively influences steroid hormone synthesis and spermatogenesis. Lipopolysaccharide (LPS), a major component of the Gram-negative bacterial cell wall, acts via toll like receptors 4 (TLR4) to trigger innate immune responses and activate nuclear factor kappa B signaling. The protective mechanisms of melatonin on LPS-induced infectious orchitis have not been reported. Herein, we developed an LPS-induced sheep infectious orchitis model. In this model, the phagocytic activity of testicular macrophages (TM) was enhanced after melatonin treatment. Moreover, we found that melatonin suppressed secretion of TM pro-inflammatory factors by suppressing the p38MAPK pathway and promoting Leydig cell testosterone secretion. Expressions of GTP cyclohydrolase-I and NADPH oxidase-2 were reduced by melatonin while heme oxygenase-1 expression was up-regulated. Thus, melatonin reduced the severity of LPS-induced orchitis by stimulating antioxidant activity. The results of this study provide a reference for the treatment of acute infectious orchitis. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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16. Role of Caspase 2 in Apoptotic Signaling in Primate and Murine Germ Cells1
- Author
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Johnson, Candace, Jia, Yue, Wang, Christina, Lue, Yan-He, Swerdloff, Ronald S., Zhang, Xue-Shen, Hu, Zhao-Yuan, Li, Yin-Chuan, Liu, Yi-Xun, and Hikim, Amiya P. Sinha
- Published
- 2008
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17. Signaling Pathways for Germ Cell Death in Adult Cynomolgus Monkeys (Macaca fascicularis) Induced by Mild Testicular Hyperthermia and Exogenous Testosterone Treatment1
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Jia, Yue, Hikim, Amiya P. Sinha, Lue, Yan-He, Swerdloff, Ronald S., Vera, Yanira, Zhang, Xue-Shen, Hu, Zhao-Yuan, Li, Yin-Chuan, Liu, Yi-Xun, and Wang, Christina
- Published
- 2007
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18. Development, function and fate of fetal Leydig cells.
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Wen, Qing, Cheng, C.Yan, and Liu, Yi-Xun
- Subjects
- *
LEYDIG cells , *FETAL development , *PROGENITOR cells , *TESTIS development , *TIGHT junctions , *BIOMOLECULES - Abstract
During fetal testis development, fetal Leydig cells (FLCs) are found to be originated from multiple progenitor cells. FLC specification and function are under tight regulation of specific genes and signaling proteins. Furthermore, Sertoli cells play a crucial role to regulate FLC differentiation during fetal testis development. FLC progenitor- and FLC-produced biomolecules are also involved in the differentiation and activity of rodent FLCs. The main function of FLCs is to produce androgens to masculinize XY embryos. However, FLCs are capable of producing androstenedione but not testosterone due to the lack of 17β-HSD (17β-hydroxysteroid dehydrogenase), but fetal Sertoli cells express 17β-HSD which thus transforms androstenedione to testosterone in the fetal testis. On the other hand, FLCs produce activin A to regulate Sertoli cell proliferation, and Sertoli cells in turn modulate testis cord expansion. It is now generally accepted that adult Leydig cells (ALCs) gradually replace FLCs during postnatal development to produce testosterone to support spermatogenesis as FLCs undergo degeneration in neonatal and pre-pubertal testes. However, based on studies using genetic tracing mouse models, FLCs are found to persist in adult testes, making up ∼20% of total Leydig cells. In this review, we evaluate the latest findings regarding the development, function and fate of FLCs during fetal and adult testis development. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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19. Signaling pathways regulating blood–tissue barriers — Lesson from the testis.
- Author
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Wen, Qing, Tang, Elizabeth I., Gao, Ying, Jesus, Tito T., Chu, Darren S., Lee, Will M., Wong, Chris K.C., Liu, Yi-Xun, Xiao, Xiang, Silvestrini, Bruno, and Cheng, C. Yan
- Subjects
- *
TISSUES , *ANTIBIOTICS , *GAP junctions (Cell biology) , *MICROTUBULES , *SPERMATOGENESIS , *CYTOSKELETON , *EPITHELIAL cells - Abstract
Signaling pathways that regulate blood–tissue barriers are important for studying the biology of various blood–tissue barriers. This information, if deciphered and better understood, will provide better therapeutic management of diseases particularly in organs that are sealed by the corresponding blood–tissue barriers from systemic circulation, such as the brain and the testis. These barriers block the access of antibiotics and/or chemotherapeutical agents across the corresponding barriers. Studies in the last decade using the blood–testis barrier (BTB) in rats have demonstrated the presence of several signaling pathways that are crucial to modulate BTB function. Herein, we critically evaluate these findings and provide hypothetical models regarding the underlying mechanisms by which these signaling molecules/pathways modulate BTB dynamics. This information should be carefully evaluated to examine their applicability in other tissue barriers which shall benefit future functional studies in the field. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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