This commentary is to critique the revised World Health Organization （WHO） semen analysis manual as it pertains to characteristics of a spermatozoon at spermiation. The aims of the revised WHO manual include improvi...This commentary is to critique the revised World Health Organization （WHO） semen analysis manual as it pertains to characteristics of a spermatozoon at spermiation. The aims of the revised WHO manual include improving the ＇quality of semen analysis＇ without any restriction to clinical use. Furthermore, the manual states that semen analysis may be useful for （a） ＇investigating male fertility status＇ and （b） ＇monitoring spermatogenesis during and following male fertility regula- tion.＇ However, if the analysis of ejaculated spermatozoa is intended for the purposes described in （b）, then cells that are abnormal at spermiation must be identified. This paper takes the position that the manual does not identify methods to estimate the quality of spermatozoa at spermiation. Instead, it uses a ＇gold standard＇ of sperm passing through the cervical mucus or arriving near the site of fertilization. Although this standard is appropriate for drawing conclusions regarding the probability that an individual could impregnate his partner, it is not appropriate for studying illness of the testes per se. Herein, the measures of sperm quality presented in the WHO manual are critiqued with respect to the detection of spermatozoa that were abnormal at spermiation vs. those that became abnormal subsequently. Quality assessments based on the percentage of motile or ＇viable＇ spermatozoa are meaningless. Alternative quality attributes defining spermatozoa at spermiation are presented in this paper. In conclusion, assessment of spermatozoal quality at spermiation, on the basis of quality attributes of individual ejaculated spermatozoa, is best achieved through application of （a） a new paradigm for the morphological evaluation of sperm quality and （b） modern analytical techniques to evaluate, in an adequate sample, several appropriate independent attributes in each spermatozoon in order to more accurately identify the proportion of abnormal spermatozoa.展开更多
Spermiation is the process that releases mature spermatids from Sertoli cells into the lumen of the seminiferous tubule.Tubulobulbar complexes(TBCs)are elaborate cytoskeleton-related structures that are indispensable ...Spermiation is the process that releases mature spermatids from Sertoli cells into the lumen of the seminiferous tubule.Tubulobulbar complexes(TBCs)are elaborate cytoskeleton-related structures that are indispensable for spermiation.Despite well-defined ultrastructural events,the molecular regulation of TBCs during spermiation re-mains largely unknown.Here,we show that autophagy is active in TBC regions,and impaired autophagy in Sertoli cells affects spermiation.Further studies demonstrated that many TBC components bound to LC3 and could be selectively degraded through the autophagy-lysosome pathway.Perturbed autophagy impaired the degradation of some TBC components in Sertoli cells,such as VCL and CTTN,and led to the accumulation of TBC compo-nents surrounding the spermatid head,which may be associated with the sperm-releasing defect.Together,our results reveal that autophagy is essential for the TBC components degradation in mouse Sertoli cells and define a functional role of autophagy during spermiation.展开更多
Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal c...Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal contents, internalize and recycle junctional complexes by endocytosis prior to spermiation. However, in addition to recycling some of the molecules undergo lysosomal degradation. The molecular machinery involved in endocytosis at the TBCs is not well understood. To bridge this gap localization of various proteins, involved at various steps of endocytosis studied in other systems, was demonstrated in TBCs using testicular fragmented material or sections by immunoblotting and immunofluroscence. The presence of key molecules like Vamp-2, syntaxin and Lamp-2 indicates occurrence of lysosomal degradation in addition to junctional recycling at the TBCs present at the time of sperm release. TBCs are endocytic devices functioning to recycle junctional molecules or remove spermatid cytoplasm that were present between spermatids and Sertoli-cells all through the process of spermatid maturation and in turn regulate male fertility.展开更多
We have demonstrated for the first time that (ⅰ) mouse Sertoli cells predominantly secrete tPA under the action of FSH and cAMP-generating agents, whereas Leydig cells mainly produce uPA; (ⅱ) Sertoli cells are also ...We have demonstrated for the first time that (ⅰ) mouse Sertoli cells predominantly secrete tPA under the action of FSH and cAMP-generating agents, whereas Leydig cells mainly produce uPA; (ⅱ) Sertoli cells are also capable of secreting PAI-1, as well as FSH, growth factors and GnRH increase PAI-1 gene expression; (ⅲ) the increases in tPA and PAI-1 activities by different hormones in the conditioned media of Sertoli cells correspond to the increases in the levels of tPA and PAI-1 mRNA in the cultured cells, suggesting that the synthesis of the activator-inhibitor in mouse Sertoli cells is regulated at a transcriptional level and the tPA secreted by Sertoli cells may be involved in the spermatogenesis.展开更多
文摘This commentary is to critique the revised World Health Organization （WHO） semen analysis manual as it pertains to characteristics of a spermatozoon at spermiation. The aims of the revised WHO manual include improving the ＇quality of semen analysis＇ without any restriction to clinical use. Furthermore, the manual states that semen analysis may be useful for （a） ＇investigating male fertility status＇ and （b） ＇monitoring spermatogenesis during and following male fertility regula- tion.＇ However, if the analysis of ejaculated spermatozoa is intended for the purposes described in （b）, then cells that are abnormal at spermiation must be identified. This paper takes the position that the manual does not identify methods to estimate the quality of spermatozoa at spermiation. Instead, it uses a ＇gold standard＇ of sperm passing through the cervical mucus or arriving near the site of fertilization. Although this standard is appropriate for drawing conclusions regarding the probability that an individual could impregnate his partner, it is not appropriate for studying illness of the testes per se. Herein, the measures of sperm quality presented in the WHO manual are critiqued with respect to the detection of spermatozoa that were abnormal at spermiation vs. those that became abnormal subsequently. Quality assessments based on the percentage of motile or ＇viable＇ spermatozoa are meaningless. Alternative quality attributes defining spermatozoa at spermiation are presented in this paper. In conclusion, assessment of spermatozoal quality at spermiation, on the basis of quality attributes of individual ejaculated spermatozoa, is best achieved through application of （a） a new paradigm for the morphological evaluation of sperm quality and （b） modern analytical techniques to evaluate, in an adequate sample, several appropriate independent attributes in each spermatozoon in order to more accurately identify the proportion of abnormal spermatozoa.
基金supported by the National Science Fund for Distinguished Young Scholars(81925015)the Youth Innovation Promotion Association of CAS(2018109).
文摘Spermiation is the process that releases mature spermatids from Sertoli cells into the lumen of the seminiferous tubule.Tubulobulbar complexes(TBCs)are elaborate cytoskeleton-related structures that are indispensable for spermiation.Despite well-defined ultrastructural events,the molecular regulation of TBCs during spermiation re-mains largely unknown.Here,we show that autophagy is active in TBC regions,and impaired autophagy in Sertoli cells affects spermiation.Further studies demonstrated that many TBC components bound to LC3 and could be selectively degraded through the autophagy-lysosome pathway.Perturbed autophagy impaired the degradation of some TBC components in Sertoli cells,such as VCL and CTTN,and led to the accumulation of TBC compo-nents surrounding the spermatid head,which may be associated with the sperm-releasing defect.Together,our results reveal that autophagy is essential for the TBC components degradation in mouse Sertoli cells and define a functional role of autophagy during spermiation.
文摘Tubulobulbar Complexes (TBCs) are actin-rich structures formed between Sertoli-cells and spermatids at the time of sperm release. The main functions of the TBCs are to remove excess spermatid cytoplasm and acrosomal contents, internalize and recycle junctional complexes by endocytosis prior to spermiation. However, in addition to recycling some of the molecules undergo lysosomal degradation. The molecular machinery involved in endocytosis at the TBCs is not well understood. To bridge this gap localization of various proteins, involved at various steps of endocytosis studied in other systems, was demonstrated in TBCs using testicular fragmented material or sections by immunoblotting and immunofluroscence. The presence of key molecules like Vamp-2, syntaxin and Lamp-2 indicates occurrence of lysosomal degradation in addition to junctional recycling at the TBCs present at the time of sperm release. TBCs are endocytic devices functioning to recycle junctional molecules or remove spermatid cytoplasm that were present between spermatids and Sertoli-cells all through the process of spermatid maturation and in turn regulate male fertility.
基金Project supported by the National Natural Science Foundation of China and Swedish Medical Research Council.
文摘We have demonstrated for the first time that (ⅰ) mouse Sertoli cells predominantly secrete tPA under the action of FSH and cAMP-generating agents, whereas Leydig cells mainly produce uPA; (ⅱ) Sertoli cells are also capable of secreting PAI-1, as well as FSH, growth factors and GnRH increase PAI-1 gene expression; (ⅲ) the increases in tPA and PAI-1 activities by different hormones in the conditioned media of Sertoli cells correspond to the increases in the levels of tPA and PAI-1 mRNA in the cultured cells, suggesting that the synthesis of the activator-inhibitor in mouse Sertoli cells is regulated at a transcriptional level and the tPA secreted by Sertoli cells may be involved in the spermatogenesis.
