Alteration Expression of Bax, Bcl-2 and VDAC1 Genes in Oligozoospermic and Fertile Subjects

Starvation-induced autophagy modulates spermatogenesis and sperm quality in Nile tilapia

Spermatogenesis is a finely regulated process that involves the interaction of several cellular mechanisms to ensure the proper development and maturation of germ cells. This study assessed autophagy contribution and its relation to apoptosis in fish spermatogenesis during starvation. To that end, Nile tilapia males were subjected to 0 (control), 7, 14, 21, and 28 days of starvation to induce autophagy. Testes samples were obtained for analyses of spermatogenesis by histology, electron microscopy, immunohistochemistry, and western blotting. Sperm quality was assessed using a computer-assisted sperm analysis (CASA) system. Data indicated a significant reduction in gonadosomatic index, seminiferous tubule area, and spermatozoa proportion in fish subject to starvation compared to the control group. Immunoblotting revealed a reduction of Bcl2 and Beclin 1 associated with increased Bax and Caspase-3, mainly after 21 and 28 days of starvation. LC3 and P62 indicated reduced autophagic flux in these starvation times. Immunolabeling for autophagic and apoptotic proteins occurred in all development stages of the germ cells, but protein expression varied throughout starvation. Beclin 1 and Cathepsin D decreased while Bax and Caspase-3 increased in spermatocytes, spermatids, and spermatozoa after 21 and 28 days. Autophagic and lysosomal proteins colocalization indicated the fusion of autophagosomes with lysosomes and lysosomal degradation in spermatogenic cells. The CASA system indicated reduced sperm motility and velocity in animals subjected to 21 and 28 days of starvation. Altogether, the data support autophagy acting at different spermatogenesis stages in Nile tilapia, with decreased autophagy and increased apoptosis after 21 and 28 days of starvation, which results in a decrease in the spermatozoa number and sperm quality.

Identification of postnatal development dependent genes and proteins in porcine epididymis

BACKGROUND

The epididymis is a highly regionalized tubular organ possesses vectorial functions of sperm concentration, maturation, transport, and storage. The epididymis-expressed genes and proteins are characterized by regional and developmental dependent pattern. However, a systematic and comprehensive insight into the postnatal development dependent changes in gene and protein expressions of porcine epididymis is still lacking. Here, the RNA and protein of epididymis of Duroc pigs at different postnatal development stages were extracted by using commercial RNeasy Midi kit and extraction buffer (7 M Urea, 2 M thiourea, 3% CHAPS, and 1 mM PMSF) combined with sonication, respectively, which were further subjected to transcriptomic and proteomic profiling.

RESULTS

Transcriptome analysis indicated that 198 and 163 differentially expressed genes (DEGs) were continuously up-regulated and down-regulated along with postnatal development stage changes, respectively. Most of the up-regulated DEGs linked to functions of endoplasmic reticulum and lysosome, while the down-regulated DEGs mainly related to molecular process of extracellular matrix. Moreover, the following key genes INSIG1, PGRMC1, NPC2, GBA, MMP2, MMP14, SFRP1, ELN, WNT-2, COL3A1, and SPARC were highlighted. A total of 49 differentially expressed proteins (DEPs) corresponding to postnatal development stages changes were uncovered by the proteome analysis. Several key proteins ACSL3 and ACADM, VDAC1 and VDAC2, and KNG1, SERPINB1, C3, and TF implicated in fatty acid metabolism, voltage-gated ion channel assembly, and apoptotic and immune processes were emphasized. In the integrative network, the key genes and proteins formed different clusters and showed strong interactions. Additionally, NPC2, COL3A1, C3, and VDAC1 are located at the hub position in each cluster.

CONCLUSIONS

The identified postnatal development dependent genes and proteins in the present study will pave the way for shedding light on the molecular basis of porcine epididymis functions and are useful for further studies on the specific regulation mechanisms responsible for epididymal sperm maturation.

Inhibition of VDAC1 prevents oxidative stress and apoptosis induced by bisphenol A in spermatogonia via AMPK/mTOR signaling pathway

Bisphenol A (BPA), one of the main components of industrial products, is clinically associated with the increased male infertility rate. However, the underlying molecular mechanism of the BPA-resulted reproductive toxicity is not fully elucidated. Voltage-dependent anion channel 1 (VDAC1) is a pore protein and located at the outer mitochondrial membrane. As a mitochondrial gatekeeper, VDAC1 controls the release of reactive oxygen species (ROS) and the metabolic and energetic functions of mitochondria, and serves as a critical player in mitochondrial-mediated apoptosis. Herein, we explored the role of VDAC1 in BPA-induced apoptosis of spermatogonia. The results showed that BPA increased spermatogonia cell line GC-1 spg cell apoptosis and intracellular ROS level, and suppressed AMPK/mTOR signaling pathway at a dose of 80 μM for 48 hr. Lentivirus-mediated short hairpin RNA targeting VDAC1 (Lv-shVDAC1) silenced VDAC1 expression and enhanced BPA-restricted cell viability. Knockdown of VDAC1 inhibited the apoptosis of BPA-treated GC-1 spg cells determined by with changes of the expressions of pro-apoptotic and anti-apoptotic proteins. Knockdown of VDAC1 also alleviated the BPA-triggered intracellular ROS generation and oxidative stress. Moreover, silence of VDAC1 increased AMPKα1/2 phosphorylation and suppressed mTOR phosphorylation under BPA exposure. Dorsomorphin, an AMPK inhibitor, partially abolished the effects of VDAC1 gene silencing on BPA-stimulated GC-1 spg cells. In conclusion, inhibition of VDAC1 attenuated the BPA-induced oxidative stress and apoptosis and promoted the cell viability in spermatogonia through modulating AMPK/mTOR signaling pathway.

Homo Sapiens (Human) microRNA 187 Expression Is Dysregulated in Testis of Non-obstructive Azoospermic Men

Introduction: MiRNA expression alterations are closely related to growth, proliferation, and cell development. In addition, miR-187 has been found to regulate cellular proliferation. Further, spermatogenesis is a highly complicated process which is regulated through several genes targeted by miRNAs. However, no study has completely addressed the etiology of spermatogenic impairments. Accordingly, the present study examined the expression pattern of Homo sapiens (human) microRNA (hsa-mir-187) in the testicular biopsies of infertile men with non-obstructive azoospermia (NOA) and Sertoli cell-only syndrome (SCOS) subtype in comparison with those with obstructive azoospermia (OA). Methods: Quantitative reverse‐transcription polymerase chain reaction analysis was performed to assess the expression level of hsa-mir-187 using the ΔΔCt method. Results: Our data indicated that hsa-mir-187 was significantly up-regulated in the testis of the SCOS group (P˂ 0.05) in comparison with the OA group. Conclusion: In general, the findings suggest that the differential expression of hsa-mir-187 is linked with male infertility and shed more light on molecular defects that underlie spermatogenic impairments.