Gossypol repressed the gap junctional intercellular communication between Sertoli cells by decreasing the expression of Connexin43

Gossypol ameliorates the IL-1β-induced apoptosis and inflammation in chondrocytes by suppressing the activation of TLR4/MyD88/NF-κB pathway via downregulating CX43

The effects of anti-inflammatory drug gossypol on osteoarthritis (OA) treatment were discussed in this paper. After identified using toluidine blue and immunofluorescence staining of type II collagen, chondrocytes from OA patients were treated with interleukin-1β (IL-1β), gossypol, and overexpressed connexin43 (CX43). In treated chondrocytes, according to MTT assay and flow cytometry, gossypol increased viability and reduced apoptosis of IL-1β induced chondrocytes. Enzyme linked immunosorbent assay (ELISA) suggested that gossypol downregulated inflammatory tumor necrosis factor (TNF)-α level. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot confirmed that gossypol downregulated CX43, nuclear factor-kappa B (NF-κB) p65, TNF-α, toll like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (MyD88) and interleukin-6 (IL-6) expressions. Besides, overexpressed CX43 reversed the effects of gossypol on viability, apoptosis, and expressions of factors related to TLR4/MyD88/NF-κB pathway of IL-1β-induced chondrocytes. In conclusion, gossypol ameliorates IL-1β-induced apoptosis and inflammation in chondrocytes by suppressing TLR4/MyD88/NF-κB pathway via downregulating CX43.

Testis Toxicants: Lesson from Traditional Chinese Medicine (TCM)

The testis is one of the organs in the mammalian body that is sensitive to toxicants. Accumulating evidence has shown that human exposure to toxic ingredients in Traditional Chinese Medicine (TCM), such as triptolide, gossypol, cannabidol, piperine, α-solanine, matrine, aristolochic acid, and emodin, lead to testis injury and reproductive dysfunction. The most obvious phenotype is reduced sperm counts due to defects in spermatogenesis. Studies have also shown that Sertoli cells in the seminiferous tubule, the functional unit of the testis that supports spermatogenesis, are the cell type that is most sensitive to the disruptive effects of toxicants. Since Sertoli cells are the "mother cells" that nurture germ cell development, Sertoli cell injury thus leads to failure in germ cell development in the seminiferous epithelium. Mounting evidence has shown that the Sertoli cell cytoskeletons, mitochondria function, Leydig cells steroidogenesis pathways and sperm ion channels are some of the prime targets of toxicants from TCM. We carefully evaluate recent findings in this area of research herein, and to provide a summary of these findings, including some insightful information regarding the underlying molecular basis of toxicant-induced testis injury that impede spermatogenesis.

Action of db-cAMP on the bystander effect and chemosensitivity through connexin 43 and Bcl-2-mediated pathways in medulloblastoma cells

Medulloblastoma (MB) is one of the most common malignant brain tumors of childhood and is associated with a poor prognosis. Gap-junctional intercellular communication (GJIC) is an important mode for cell-to-cell communication. Dysfunctional GJIC is exhibited in most cancer cells. There is significant evidence that GJIC is important in at least some prodrug/suicide gene systems by augmenting the bystander effect (BE). GJIC is made up of connexins (Cxs), among which Cx43 is present in most tissues. Bcl-2, an important apoptosis blocker, is closely associated with the sensitivity to anticancer drugs. Our study showed that dibutyryl cyclic adenosine monophosphate (db-cAMP) upregulated the Cx43 expression and GJIC function in Daoy medulloblastoma cells. It directly enhanced the BE using a herpes simplex virus thymidine kinase (HSV‑tk)/ganciclovir (GCV) system, which was blocked by a Cx43 inhibitor. In addition, db-cAMP increased the cytotoxicity of temozolomide and teniposide, possibly by downregulating the Bcl-2 expression and inducing apoptosis. Taken together, we demonstrated the beneficial effect of db-cAMP in treating medulloblastoma depending on the upregulation of BE and chemosensitivity through Cx43 and Bcl-2-mediated pathways.

Connexin 43 gene expression in male and female gonads of porcine offspring following in utero exposure to an anti-androgen, flutamide

The aim of this study was to show the effect of maternal exposure to flutamide on connexin 43 (Cx43) gene expression in testes and ovaries of 2-day-old piglets. Additionally, anogenital distance (AGD) was measured both in male and female offspring. Immunohistochemistry, Western blotting, and RT-PCR were performed to assess the immunoreactivity and the presence of Cx43 protein and it's mRNA, respectively. Following flutamide exposure strong immunostaining for Cx43 was observed between testicular Leydig cells, between granulosa cells of primary follicles, and between interstitial cells surrounding clusters of oocyte nests in the ovarian cortex as in the respective controls. Differences between the flutamide-treated groups and the controls obtained by qualitative immunohistochemistry were confirmed by quantitative image analysis (*P<0.05; **P<0.01). In Western blotting, Cx43 appeared as a band of 43kDa, whereas electrophoresis revealed PCR products of the predicted sizes. Screening for Cx43 expression revealed the presence of a transcript, both in control and in flutamide-treated pigs. The AGD values differed significantly from the control (*P<0.05). Overall, since no obvious changes in gonad morphology were observed and the Cx43 signal was present in all the examined tissues, it seems likely that androgens acting through ARs are not involved in the control of Cx43 gene expression in neonatal pig gonads.

Physiological and physiopathological aspects of connexins and communicating gap junctions in spermatogenesis

Spermatogenesis is a highly regulated process of germ cell proliferation and differentiation, starting from spermatogonia to spermatocytes and giving rise to spermatids, the future spermatozoa. In addition to endocrine regulation, testicular cell-cell interactions are essential for spermatogenesis. This precise control is mediated through paracrine/autocrine pathways, direct intercellular contacts and through intercellular communication channels, consisting of gap junctions and their constitutive proteins, the connexins. Gap junctions are localized between adjacent Leydig cells, between Sertoli cells and between Sertoli cells and specific germ cells. This review focuses on the distribution of connexins within the seminiferous epithelium, their participation in gap junction channel formation, the control of their expression and the physiological relevance of these junctions in both the Sertoli-Sertoli cell functional synchronization and the Sertoli-germ cell dialogue. In this review, we also discuss the potential implication of disrupted connexin in testis cancer, since impaired expression of connexin has been described as a typical feature of tumoral proliferation.