Germline FOXJ2 overexpression causes male infertility via aberrant autophagy activation by LAMP2A upregulation.

Spermatogenesis is a complex biological process that produces haploid spermatozoa and requires precise regulation by many tissue-specific factors. In this study, we explored the role and mechanism of Fork head box J2 (FOXJ2, which is highly expressed in spermatocytes) in the regulation of spermatogenesis using a germline-specific conditional Foxj2 knock-in mouse model (Stra8-Cre; Foxj2 tg/tg mouse). Foxj2 overexpression in mouse testes led to spermatogenesis failure, which started at the initiation of meiosis, and resulted in male infertility. Lysosomes and autophagy-related genes were upregulated in Stra8-cre; Foxj2 tg/tg mouse testes and the number of autolysosomes in the spermatocytes in Stra8-cre; Foxj2 tg/tg mice was increased. Chromatin immunoprecipitation-PCR and Dual-luciferase reporter assays showed that Lamp2 (encoding lysosome-associated membrane protein-2) was a target of FOXJ2. Foxj2 overexpression increased the expression levels of Lamp2a and Hsc70 (70-kDa cytoplasmic heat shock protein) in the Stra8-cre; Foxj2 tg/tg mouse testes. Our results suggested that Foxj2 overexpression in the germ cells of mouse testes affects chaperone-mediated autophagy by upregulating LAMP2A, leading to spermatogenesis failure at the initiation of meiosis, thus resulting in male infertility. Our findings provide a new insight into the function of FOXJ2 in spermatogenesis and the significance of autophagy regulation in spermatogenesis.

[Impact of overexpressed FOXJ2 on mouse spermatogenesis and its action mechanism].

OBJECTIVE: To analyze the phenotype of the male reproductive system in the germline-specific conditional Foxj2 knock-in mouse model (Stra8-cre; Foxj2tg/+), identify a target gene of the transcription factor FOXJ2, and investigate the effect of the overexpression of Foxj2 on mouse spermatogenesis and its action mechanism. METHODS: Based on the Cre-loxP recombination system, we generated a germline-specific conditional Foxj2 knock-in mouse model (Stra8-cre; Foxj2tg/+). We determined male fertility by counting the number of pups per litter and the fertilization rate after intracytoplasmic sperm injection (ICSI), observed the morphology of the testes and epididymides by HE staining, examined the sperm quality by computer assisted sperm analysis (CASA), detected the expression and localization of Cx43 in the testis by RT-qPCR, Western blot and immunohistochemistry, and verified the binding site of FOXJ2 to the Cx43 promoter using ChIP-PCR and dual luciferase reporter assay. RESULTS: The number of pups per litter and fertilization rate after ICSI were lower in the Stra8-cre; Foxj2tg/+ male mice than in the controls, and so were the size and weight of the testis. HE staining exhibited obvious exfoliation of germ cells and dramatically decreased spermatocytes and spermatids in the seminiferous tubules of the Stra8-cre; Foxj2tg/+ mice. Moreover, sperm concentration in the cauda epididymides was reduced, and the transcription and expression levels of Cx43 in the testis were increased. ChIP-PCR and dual luciferase reporter assay showed direct binding of FOXJ2 to the Cx43 promoter in the testis. CONCLUSIONS: Overexpressed FOXJ2 may lead to spermatogenic failure and subfertility in Stra8-cre; Foxj2tg/+ male mice by upregulating the expression of Cx43.

Control of multiciliogenesis by miR-34/449 in the male reproductive tract through enforcing cell cycle exit.

Multiciliated cells (MCCs) are terminally differentiated postmitotic cells that possess hundreds of motile cilia on their apical surface. Defects in cilia formation are associated with ciliopathies that affect many organs. In this study, we tested the role and mechanism of the miR-34/449 family in the regulation of multiciliogenesis in EDs using an miR-34b/c-/-; miR-449-/- double knockout (dKO) mouse model. MiR-34b/c and miR-449 depletion led to a reduced number of MCCs and abnormal cilia structure in the EDs starting from postnatal day (P)14. However, abnormal MCC differentiation in the dKO EDs could be observed as early as P7. RNA-seq analyses revealed that the aberrant development of MCCs in the EDs of dKO mice was associated with the upregulation of genes involved in cell cycle control. Using a cyclin-dependent kinase inhibitor to force cell cycle exit promoted MCC differentiation, and partially rescued the defective multiciliogenesis in the EDs of dKO mice. Taken together, our results suggest that miR-34b/c and miR-449 play an essential role in multiciliogenesis in EDs by regulating cell cycle exit.

[Effects of miR-34b/c and miR-449 on the morphology and function of efferent ductules in mice: A transcriptomics-based analysis].

OBJECTIVE: To investigate the role of miR-34b/c and miR-449 in maintaining the normal structure and function of efferent ductules and explore the molecular mechanism of infertility in miR-34b/c－/－ and miR-449－/－ dKO mice. METHODS: We observed the morphology of mouse efferent ductules by HE staining and analyzed the gene expressions in the efferent ductules of the wild-type and miR-34b/c－/－ and miR-449－/－ dKO mice by RNA sequencing. Then we screened the possible target genes of these two miRNA clusters and analyzed them along with the differentially expressed genes, followed by verification of the sequencing results by qRT-PCR. RESULTS: Compared with the wild-type, the dKO mice showed morphologically abnormal efferent ductules and significantly decreased expressions of the genes involved in the formation of cilia and related to the transportation of water, ion and protein in the efferent ductules. CONCLUSIONS: The deletion of miR-34b/c and miR-449 led to morphological abnormality of efferent ductules and dysfunction of aberrant cilia motility and reabsorption in the efferent ductules of dKO mice, resulting in infertility.

[Anomalous absorption and a qualified far infrared spectrum].

The ideal 100% line could not be obtained when the content of water vapor in the spectrometer is constant but high during the whole procedure of a far-infrared spectrum collection. This result indicates that anomalous absorption phenomenon takes place in high relative humidity atmosphere. In the present paper, the influences of the relative humidity of ambient air and spectral resolution on anomalous absorption were studied. It was found that both decreasing the water vapor content in the spectrometer and adopting low spectral resolution are effective methods to avoid anomalous absorption. Furthermore, the water vapor bands can be eliminated by "dry air and wet air titration" in the fluctuant humidity. This provides us a quick and economic method to obtain a qualified far infrared spectrum conveniently. It should be noticed that the working condition for "dry air and wet air titration" is low relative humidity to prevent water vapor abnormal absorption.

Inhibition of mouse acrosome reaction and sperm-zona pellucida binding by anti-human sperm membrane protein 1 antibody.

AIM: To investigate the possible functions of human sperm membrane protein (hSMP-1) in the process of fertilization. METHODS: A 576-bp cDNA fragment of HSD-1 gene coding for the extracellular domain of hSMP-1 was cloned and expressed. The localization of this protein on human and mouse sperm was determined by indirect immunofluorescent staining by using anti-recombinant hSMP-1 (anti-rhSMP-1) antibodies. Sperm acrosome reaction and sperm-zona pellucida (ZP) binding assay were carried out in 10-week-old BALB/c mice. RESULTS: Recombinant hSMP-1 was successfully cloned and expressed. The expression of the native protein was limited on the acrosome of human and mouse sperm. Treatment of anti-rhSMP-1 antibodies significantly decreased the average number of sperms bound to each egg. Meanwhile, the percentage of acrosome reaction was decreased in comparison to pre-immune control after treatment with anti-rhSMP-1 (P < 0.05). CONCLUSION: The results suggest that anti-rhSMP-1 antibody inhibited mouse acrosome reaction and sperm-ZP binding.

[Cloning, expression and purification of human nuclear autoantigenic sperm protein (hNASP) and preparation of its polyclonal antibody].

OBJECTIVE: To acquire the purified human nuclear autoantigenic sperm protein (hNASP) and its polyclonal antibody for investigating the possible functions of hNASP involved in fertilization. METHODS: The coding sequence of hNASP gene was amplified from human testis RNA with specific primers, and the PCR product was cloned first into pMD-18T and then into pET-28a ( + ) after restriction digestion with BamH I and Hind III. The fusion protein was expressed in E. coli BL21 (DE3) after induction with IPTG. The recombinant protein NASP was purified from the supernatant with Ni2 -NTA His-bind resin under native conditions. RESULTS: The results of DNA sequencing and SDS-PAGE analysis showed the protein to be what we had hoped to acquire. ELISA showed that we had acquired rabbit anti-hNASP serum with high titer. CONCLUSION: High purity recombinant hNASP protein could be obtained with the above-mentioned prokaryotic expression method, and so could the rabbit anti-hNASP serum with high titer and high specificity.

Mechanisms of glucocorticoid-induced Leydig cell apoptosis.

The high levels of corticosterone (CORT) that are typically achieved during stress induce apoptotic death of Leydig cells. The intracellular mechanisms by which CORT acts on Leydig cells to induce apoptosis are unknown, and the present study tested for mediation by Fas ligand (FasL), a member of the tumor necrosis factor ligand family, in association with caspase activation. In addition, another apoptotic pathway involving in the participation of mitochondria was studied by evaluation of mitochondrial membrane potential (DeltaPsi) loss and generation of reactive oxygen species (ROS), which are early apoptotic events in many cell types. Rat Leydig cells were isolated from adrenalectomized rats on day 90 postpartum at 3, 6, 12, 24 and 48 h after the start of CORT administration (at a dose of 5 mg total/100 g body weight per day intraperitoneally in two daily injections starting 3 days after surgery). Both FasL and Fas receptor protein levels, analyzed by Western blot and fluorescent immunohistochemistry, increased at 6 h after the start of CORT administration, peaking at 24 h and declining thereafter. Leydig cell caspase-3 activity was analyzed in vitro. Low molecular weight DNA fragments that are characteristic of apoptosis were evident in Leydig cells by 12 h of exposure to 100 nM CORT in vitro, and the abundance of the fragments was more pronounced at 24 h. In the presence of a specific caspase inhibitor, Ac-DEVD-CHO, Leydig cell apoptosis was suppressed, corroborating the hypothesis that caspase-3 is involved in CORT-mediated cell death. Western blotting analysis revealed that procaspase-3 was present only at low levels in untreated control Leydig cells, and increased by 6 h of CORT administration. By 12 h, however, procaspase-3 was significantly reduced, and the cleaved, active caspase-3 forms appeared and increased through 24 h. These results indicated that FasL/Fas and caspase were implicated in CORT-mediated Leydig cell apoptosis. Decreased DeltaPsi and increased ROS generation were also measurable in Leydig cells for up to 2 days following CORT administration in vitro. These data indicate that activation of the Fas system, cleavage of procaspase-3, loss of DeltaPsi and increased ROS generation are all implicated in the process of CORT-induced Leydig cell death.