POINTIS , Georges

The gap junction proteins, connexins (Cx), are present in the testis and among them Cx43 play an essential role in spermatogenesis. By using an in vitro proliferation model of germ cells and Sertoli cells, we tempted here to clarify the role of Cx43 in the control of Sertoli and germ cell proliferation and apoptosis. Cx43 was detected in...

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Follicle-stimulating hormone (FSH) is required for initiation and maintenance of spermatogenesis, a dynamic process of cell proliferation and maturation. By using FSH-gold particles and pulse-chase experiments, we analyzed the kinetics of FSH endocytosis in Sertoli and germ cells during development. Ultrastructural time-dependent analysis...

Atrazine (ATZ), a widely used agricultural pesticide and benzo[a]pyrene (BaP), a ubiquitous environmental human carcinogen can induce alterations of spermatogenesis. In the present study, we showed first that our seminiferous tubule culture model, in bicameral chambers, allowed the settlement of the blood-testis barrier (BTB) in 8-day-old male...

Connexins (Cx), the constitutive proteins of gap junctions, are key actors of many physiological processes. Therefore alterations of Cx expression and degradation lead to the development of physiopathological disorders. Due to the formation of a double membrane vesicle termed annular gap junction (AGJ), gap junction degradation is a unique...

Gap junctional intercellular communication (GJIC) permits coordinated cellular activities during developmental and differentiation processes. In bone, the involvement of the gap junctional protein, connexin-43 (Cx43), and of GJIC in osteoblastic differentiation and mineralization of the extracellular matrix has been previously demonstrated....

Exposure to toxic metals, specifically those belonging to the nonessential group leads to human health defects and among them reprotoxic effects. The mechanisms by which these metals produce their negative effects on spermatogenesis have not been fully elucidated. By using the Durand's validated seminiferous tubule culture model, which mimics...

Connexins (Cx) are key regulators of cell proliferation, differentiation and apoptosis. Cx trafficking and endocytosis need interactions with a large number of signaling and scaffolding proteins. We demonstrate herein that Cx43-GFP gap junction plaque endocytosis was blocked in cells transfected by the dominant-negative form of dynamin2...

Several studies suggest that exposure to environmental pollutants is partly responsible for testicular pathologies that have considerably increased over the last decades (cryptorchidism, hypospadias, cancer, decrease in the number of ejaculated spermatozoa). However, the cellular and molecular mechanisms involved in this reprotoxicity remain...

It has been shown that non-cytotoxic doses of Carbendazim (CBZ), a broad-spectrum benzimidazole fungicide, possess endocrine-disrupting (androgen-like) actions, ex vivo, on the pubertal rat seminiferous epithelium. Iprodione (IPR), a dicarboximide fungicide, is also known to be an endocrine-disrupter (anti-androgen). The effect of a mixture of...

In different epithelia, cell membranes contacting one another form intercellular junctional complexes including tight, adherens and gap junctions, which could mutually influence the expression of each other. We have here investigated the role of Cx43 in the control of adherens and tight junction proteins (N-cadherin, beta-catenin, occludin and...