The transcription factor octamer-binding transforming factor 4 (Oct-4) is central to the gene regulatory network responsible for self-renewal, pluripotency, and lineage commitment in embryonic stem (ES) cells and induced pluripotent stem cells (PSCs). This study was undertaken to evaluate differential localization and expression of two major transcripts of Oct-4, viz. Oct-4A and Oct-4B, in adult human testis. A novel population of 5- to 10-μm PSCs with nuclear Oct-4A was identified by ISH and immunolocalization studies. Besides Oct-4, other pluripotent markers like Nanog and TERT were also detected by RT-PCR. A(dark) spermatogonial stem cells (SSCs) were visualized in pairs and chains undergoing clonal expansion and stained positive for cytoplasmic Oct-4B. Quantitative PCR and Western blotting revealed both the transcripts, with higher expression of Oct-4B. It is proposed that PSCs undergo asymmetric cell division and give rise to A(dark) SSCs, which proliferate and initiate lineage-specific differentiation. The darkly stained nuclei in A(dark) SSCs may represent extensive nuclear reprogramming by epigenetic changes when a PSC becomes committed. Oct-4B eventually disappeared in mature germ cells, viz. spermatocytes, spermatids, and sperm. Besides maintaining normal testicular homeostasis, PSCs may also be implicated in germ cell tumors and ES-like colonies that have recently been derived from adult human testicular tissue.

Being quiescent, VSELs possibly do not accumulate genomic (nuclear or mitochondrial) mutations and thus may be ideal endogenous, pluripotent stem cell candidates for regenerative and reproductive medicine. The presence of VSELs in adult gonads and the fact that they survive oncotherapy may obviate the need to bank gonadal tissue for fertility preservation prior to oncotherapy. VSELs and their ability to undergo spermatogenesis/neo-oogenesis in the presence of a healthy niche will help identify newer strategies toward fertility restoration in cancer survivors, delaying menopause and also enabling aged mothers to have better quality eggs.

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The most primitive germ cells in adult mammalian testis are the spermatogonial stem cells (SSCs) whereas primordial follicles (PFs) are considered the fundamental functional unit in ovary. However, this central dogma has recently been modified with the identification of a novel population of very small embryonic-like stem cells (VSELs) in the adult mammalian gonads. These stem cells are more primitive to SSCs and are also implicated during postnatal ovarian neo-oogenesis and primordial follicle assembly. VSELs are pluripotent in nature and characterized by nuclear Oct-4A, cell surface SSEA-4, and other pluripotent markers like Nanog, Sox2, and TERT. VSELs are considered to be the descendants of epiblast stem cells and possibly the primordial germ cells that persist into adulthood and undergo asymmetric cell division to replenish the gonadal germ cells throughout life. Elucidation of their role during infertility, endometrial repair, superovulation, and pathogenesis of various reproductive diseases like PCOS, endometriosis, cancer, and so on needs to be addressed. Hence, a detailed review of current understanding of VSEL biology is pertinent, which will hopefully open up new avenues for research to better understand various reproductive processes and cancers. It will also be relevant for future regenerative medicine, translational research, and clinical applications in human reproduction.

The c-kit receptor (KIT) and its ligand, stem cell factor (SCF), represent one of the key regulators of testicular formation, development, and function and have been extensively studied in various animal models. The present study was undertaken to characterize the pattern of localization and expression of c-kit in normal adult human testis. Immunohistochemical analysis showed that KIT is expressed in the cytoplasm of spermatogonia, acrosomal granules of spermatids, and Leydig cells. Interestingly, a rather heterogenous pattern of expression of the protein along the basement membrane was observed. Intense protein localization in spermatogonia was detected in stages I-III, whereas low expression was observed in stages IV-VI of the seminiferous epithelium, indicating that the expression of the molecule was stage specific. In situ hybridization studies revealed that the transcripts of the gene were also localized in a similar non-uniform pattern. To the best of our knowledge, such a stage-specific expression of KIT has not been reported previously in the human testis. The results of the present study may expand current knowledge about the c-kit/SCF system in human spermatogenesis.

Background: Several epigenetic changes are responsible for transcriptional alterations of signaling pathways and tumour suppressor genes (TSGs) contributing to carcinogenesis. This study was aimed to examine the effect of the phytochemical, genistein on various molecular targets in HeLa cells. Methods: Quantitative PCR was used to analyze the expression of various molecular targets. Biochemical assays were employed to study the epigenetic enzymes. To correlate the transcriptional status of the selected TSGs and epigenetic modulation, their promoter 5'CpG methylation levels were evaluated by quantitative methylation array followed by methylation specific restriction digestion. Results: The expression of several genes involved in the cell cycle regulation, migration, inflammation, phosphatidylinositol 3-kinase (PI3K) and mitogen activated kinase-like protein (MAPK) pathway were found to be modulated including CCNB1, TWIST1, MMP14, TERT, AKT1, PTPRR, FOS and IL1A. Genistein modulated the expression of DNA methyltransferases (DNMTs), histone deacetylases (HDACs), histone methyltransferases (HMTs), demethylases, and histone phosphorylases. Furthermore, genistein decreased the activity of DNMTs, HDACs, and HMTs and reduced global DNA methylation levels. Promoter methylation of several TSGs, including FHIT, RUNX3, CDH1, PTEN, and SOC51, was lowered with corresponding transcriptional increase. Network analysis indicated similar effect of genistein. Conclusion: This study presents a comprehensive mechanism of action of genistein showcasing effective epigenetic modulation and widespread transcriptional changes resulting in restoration of tumour suppressor gene expression. This study corroborates the development of genistein as a candidate for anti-cancer therapy.

Background: The main proteases (Mpro) and Spike Proteins (SP) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARSCoV-2) play a major role in viral infection development by producing several non-structural proteins (nsPs) and penetrating the host cells respectively. In this study, the potential of in silico molecular docking-based drug repositioning approach was exploited for identifying the inhibitors of Mpro and SP of SARS-CoV-2. Methods: A total of 196 compounds including various US-FDA-approved drugs, vitamins and their analogs were docked with Mpro (PDB IDs: 6YB7 and 6Y84), and the top six ligands were further tested for ADME properties followed by docking with SP (PDB IDs: 6LXT and 6W41). Results: Out of 196 compounds, binding energy (DE) of Silybin B (6YB7: DE: -11.20 kcal/mol; 6Y84: DE: -10.18 kcal/mol; 6LXT:DE: -10.47 kcal/mol; 6W41:DE: -10.96 kcal/mol) and Cianidanol (6YB7:DE: -8.85 kcal/mol; 6Y84:DE:-10.02 kcal/mol; 6LXT:DE:-9.36 kcal/mol; 6W41:DE: -9.52 kcal/mol) demonstrated better binding and ADME properties compared with the currently endeavored drugs like Hydroxychloroquine and Lopinavir. Additionally, Elliptinone, Diospyirin, SCHEMBL94263 and Fiboflavin have shown encouraging results. Fiboflavin, an immunity booster, was found to inhibit both the Mpro and spike protein of SARS-CoV-2. It was observed that amino acid residues MET6, ALA7, PHE8, PRO9, ASP295, GLY302, VAL303 and THR304 play significant roles in protein-ligand interactions through hydrogen bonds and Vander Waals forces. Conclusion: Silybin B and Cianidanol showed excellent binding and ADME properties compared with the currently endeavored drugs and can be exploited as therapeutic options against SARS-CoV-2 infection after experimental validation and clinical trials.

Background: The global health emergency due to SARS-CoV-2 causing the COVID-19 pandemic emphasized the scientific community to intensify their research work for its therapeutic solution. In this study, Indian traditional spices owing to various medicinal properties were tested in silico for their inhibitory activity against SARS-CoV-2 proteins. SARS-CoV-2 spike proteins (SP) and main proteases (Mpro) play a significant role in infection development were considered as potential drug targets. Methods: A total of 75 phytochemicals present in traditional Indian spices retrieved from the published literature and Dr. Duke’s Phytochemical and Ethnobotanical Database, were docked with Mpro (PDB IDs: 6YNQ), and the SP (PDB IDs: 6LXT and 6YOR). Results: Through the screening process, 75 retrieved phytochemicals were docked with spike protein (PDB IDs: 6LXT and 6YOR) and main protease (PDB ID: 6YNQ) of SARS-CoV-2. Among them, myricetin, a flavonoid (rank score: 6LXT: -11.72383; 6YOR: -9.87943; 6YNQ: -11.68164) from Allium sativumL and Isovitexin, an example of flavone (rank score:6LXT: -12.14922; 6YOR: -10.19443; 6YNQ: - 12.60603) from Pimpinella anisumL were the most potent ligands against SP and Mproof SARS-CoV-2. Whereas, Astragalin from Crocus sativusL.; Rutin from Illicium verum, Oxyguttiferone from Garcinia cambogia; Scopolin from Apium graveolens L, Luteolin from Salvia officinalis, Emodin, Aloe-emodin from Cinnamomum zeylanicium and Apigenin from Allium sativumL showed better inhibition against Mpro than SP of SARS-CoV-2. The amino acid residues like SER, LYS, ASP and TYR were found playing important role in protein-ligand interactions via hydrogen bonding and Vander Waals forces. Conclusion: Optimal use of traditional spices in our daily meals may help fight against COVID-19. This study also paves the path for herbal drug formulation against SARS-CoV-2 after wet lab validation.