Expression of hOvol2 in the XY body of human spermatocytes

OVOL2: an epithelial lineage determiner with emerging roles in energy homeostasis

Ovo like zinc finger 2 (OVOL2) is an evolutionarily conserved regulator of epithelial lineage determination and differentiation during embryogenesis. OVOL2 binds to DNA using zinc-finger domains to suppress epithelial-mesenchymal transition (EMT), which is critical for tumor metastasis. However, recent studies have suggested some noncanonical roles of OVOL2 that do not rely on the DNA binding of zinc-finger domains or regulation of EMT. OVOL2 and EMT regulators have emerging roles in adipogenesis, thermogenesis, and lipid metabolism. Here, we review different roles of OVOL2 from embryo development to adult tissue homeostasis, and discuss how OVOL2 and other EMT regulators orchestrate a regulatory network to control energy homeostasis. Last, we propose potential applications of targeting OVOL2 to reduce human obesity.

Improving effects of telmisartan on spermatogenic disorder induced by fractionated low-dose irradiation in mice

BACKGROUND

Male infertility is a hot problem worldwide, but there are few treatments, especially male infertility caused by irradiation is difficult to treat. The aim of this study was to investigate and evaluate novel drugs for the treatment of male infertility caused by irradiation.

METHODS

we randomly divided 18 male BALB/c mice into 3 groups: control, irradiated, and telmisartan. Both irradiated and telmisartan group completed whole-body 0.5 Gy five times irradiation, and the telmisartan group received intraperitoneal injection of telmisartan (1.2 mg/kg) daily on the next day after irradiation, and all groups were sampled on day 25 after irradiation.

RESULTS

Sperm motility results show that total sperm motility of irradiated group was significantly lower compared with control group, and testicular HE results showed that testis in irradiated group were severely damaged. Compared with irradiated group, the total sperm motility, sperm concentration, testicular index, Johnsen score, and the seminiferous tubule layer numbers were higher in telmisartan group (P < 0.05). The immunohistochemical staining showed γ-H2AX expression is higher in telmisartan group compared with irradiated group. And the relative mRNA expression of PLZF, GFRA1, STRA8, DMRT1, SPO11, SYCP2, OVOL2, CCNA1, TJP3, RUNX2, TXNDC2 TNP1, and PRM3 in telmisartan group was all significantly higher than irradiated group (P < 0.05).

CONCLUSION

In conclusion, in vivo experiments confirmed that telmisartan ameliorated the spermatogenic disorder in mice caused by fractionated low-dose irradiation via promoting spermatogenesis.

Defects of microtubule cytoskeletal organization in NOA human testes

The importance of actin and microtubule (MT) cytoskeletons in testis function in rodents is known to some extent, but its role in the etiology of azoospermia in humans remains unexplored. Here, we examined if MT cytoskeleton was defective in NOA (non-obstructive azoospermia) testes versus normal human testes based on histopathological, immunofluorescence (IF), and scRNA-Seq transcriptome profiling. Testis biopsy samples from n = 6 normal men versus n = 3 Sertoli cell only (SCO) and n = 3 MA (meiotic arrest) of NOA patients were used for histopathological analysis. IF analysis was also used to examine MT organization across the seminiferous epithelium, investigating the likely involvement of microtubule-associated proteins (MAPs). scRNA-Seq transcriptome profiling datasets from testes of 3 SCO patients versus 3 normal men in public domain in Gene Expression Omnibus (GEO) Sample (GSM) with identifiers were analyzed to examine relevant genes that regulate MT dynamics. NOA testes of MA and SCO patients displayed notable defects in MT organization across the epithelium with extensive truncation, mis-alignments and appeared as collapsed structures near the base of the tubules. These changes are in contrast to MTs in testes of normal men. scRNA-Seq analyses revealed considerable loss of spermatogenesis capacity in SCO testes of NOA patients versus normal men. An array of genes that support MT dynamics displayed considerable changes in expression and in spatial distribution. In summary, defects in MT cytoskeleton were noted in testes of NOA (SCO) patients, possibly mediated by defective spatial expression and/or distribution of MAPs. These changes, in turn, may impede spermatogenesis in SCO testes of NOA patients.

The Transcription Factor OVOL2 Represses ID2 and Drives Differentiation of Trophoblast Stem Cells and Placental Development in Mice

Trophoblasts are the first cell type to be specified during embryogenesis, and they are essential for placental morphogenesis and function. Trophoblast stem (TS) cells are the progenitor cells for all trophoblast lineages; control of TS cell differentiation into distinct trophoblast subtypes is not well understood. Mice lacking the transcription factor OVO-like 2 (OVOL2) fail to produce a functioning placenta, and die around embryonic day 10.5, suggesting that OVOL2 may be critical for trophoblast development. Therefore, our objective was to determine the role of OVOL2 in mouse TS cell fate. We found that OVOL2 was highly expressed in mouse placenta and differentiating TS cells. Placentas and TS cells lacking OVOL2 showed poor trophoblast differentiation potential, including increased expression of stem-state associated genes (Eomes, Esrrb, Id2) and decreased levels of differentiation-associated transcripts (Gcm1, Tpbpa, Prl3b1, Syna). Ectopic OVOL2 expression in TS cells elicited precocious differentiation. OVOL2 bound proximate to the gene encoding inhibitor of differentiation 2 (ID2), a dominant negative helix-loop-helix protein, and directly repressed its activity. Overexpression of ID2 was sufficient to reinforce the TS cell stem state. Our findings reveal a critical role of OVOL2 as a regulator of TS cell differentiation and placental development, in-part by coordinating repression of ID2.

Single-Cell RNA Sequencing Analysis Reveals Sequential Cell Fate Transition during Human Spermatogenesis

Spermatogenesis generates mature male gametes and is critical for the proper transmission of genetic information between generations. However, the developmental landscapes of human spermatogenesis remain unknown. Here, we performed single-cell RNA sequencing (scRNA-seq) analysis for 2,854 testicular cells from donors with normal spermatogenesis and 174 testicular cells from one nonobstructive azoospermia (NOA) donor. A hierarchical model was established, which was characterized by the sequential and stepwise development of three spermatogonia subtypes, seven spermatocyte subtypes, and four spermatid subtypes. Further analysis identified several stage-specific marker genes of human germ cells, such as HMGA1, PIWIL4, TEX29, SCML1, and CCDC112. Moreover, we identified altered gene expression patterns in the testicular somatic cells of one NOA patient via scRNA-seq analysis, paving the way for further diagnosis of male infertility. Our work allows for the reconstruction of transcriptional programs inherent to sequential cell fate transition during human spermatogenesis and has implications for deciphering male-related reproductive disorders.