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Adiponectin is an adipokine playing important roles in metabolic, inflammatory and proliferative processes. At the time of surgery for rhegmatogenous retinal detachment, an altered expression of adipokines has been associated with the development of future proliferative vitreoretinopathy (PVR); this evidence as well as the presence of adiponectin receptors in ocular tissues and cell lines suggests a role of adiponectin in the physio-pathology of ocular conditions. Here, we investigated the effects of AdipoRon, an adiponectin agonist, on ARPE-19, a human retinal pigment epithelial cell line after confirming the expression of AdipoR1, AdipoR2, T-cadherin receptors. We evaluated the effects of AdipoRon in terms of vitality, survival, and migration; furthermore, we investigated the potential effects of AdipoRon on the inflammatory state of ARPE-19 cells analysing the levels of IL-10, VEGF, MCP-1 and IL-6 cytokines. Our findings indicated that AdipoRon, in a time and dose-dependent manner, reduces cell proliferation, migration, and colony formation of ARPE-19 cells. On the contrary, AdipoRon administration does not affect the expression of the tested cytokines. In conclusion, our results indicated that AdipoRon, may constitute an endogenous inhibitor of retinal pigment epithelial cell proliferation and migration, both processes deeply involved in development of PVR. Since PVR are characterized by an aberrant growth, migration and dedifferentiation of retinal pigment epithelial cells, our data contribute to open new fields of research to develop innovative therapeutic targets. Further studies are needed to clarify the effects of AdipoRon and of other small-molecule adiponectin analogs on retinal epithelium to clarify the functional role of adiponectin.

Metabolic Syndrome prevalence has reaching epidemic proportions worldwide. Adiponectin (Acrp30), and in particular its High Molecular Weight (HMW) oligomers, contributes to enhance insulin sensitivity and to reduce inflammation levels. Physical exercise improves body's biochemical balance and metabolism resulting effective in prevention of metabolic diseases. Whether improvement of metabolic features mediated by physical exercise is associated with changes in Acrp30 serum composition is not yet clarified. In the present study, we investigated total Acrp30 expression, its oligomeric status and genetic variants in adiponectin gene (ACDC) in twenty-two professional Water Polo (WP) Players and 40 age- and sex-matched controls. Anthropometric, metabolic parameters and total Acrp30 were assessed; Acrp30 oligomeric profile was characterized by Western blot as well as by FPLC analysis. ACDC gene was analyzed by direct-sequencing analysis. Significant elevated body mass index, aspartate aminotransferase and lactate dehydrogenase levels and, conversely, significantly lower concentrations of total and cholesterol low density lipoprotein were present in WP players. No significant difference was found in total Acrp30 and/or HMW oligomers. Interestingly, in WP players, a direct relationship between total Acrp30 and monocytes as well as an inverse relationship between total Acrp30 and AST levels were found. ACDC screening revealed previously described SNPs. In conclusion, our study confirms the long-term beneficial effects of high physical training on metabolism and suggests that they are not associated with Acrp30 and/or HMW oligomers changes. Moreover, the correlation of Acrp30 with monocytes in WP athletes could represent a mechanism by which Acrp30 participates in exercise-induced anti-inflammatory functions and/or cardiovascular health. Metabolic Syndrome prevalence has reaching epidemic proportions worldwide. Adiponectin (Acrp30), and in particular its High Molecular Weight (HMW) oligomers, contributes to enhance insulin sensitivity and to reduce inflammation levels. Physical exercise improves body's biochemical balance and metabolism resulting effective in prevention of metabolic diseases. Whether improvement of metabolic features mediated by physical exercise is associated with changes in Acrp30 serum composition is not yet clarified. In the present study, we investigated total Acrp30 expression, its oligomeric status and genetic variants in adiponectin gene (ACDC) in twenty-two professional Water Polo (WP) Players and 40 age- and sex-matched controls. Anthropometric, metabolic parameters and total Acrp30 were assessed; Acrp30 oligomeric profile was characterized by Western blot as well as by FPLC analysis. ACDC gene was analyzed by direct-sequencing analysis. Significant elevated body mass index, aspartate aminotransferase and lactate dehydrogenase levels and, conversely, significantly lower concentrations of total and cholesterol low density lipoprotein were present in WP players. No significant difference was found in total Acrp30 and/or HMW oligomers. Interestingly, in WP players, a direct relationship between total Acrp30 and monocytes as well as an inverse relationship between total Acrp30 and AST levels were found. ACDC screening revealed previously described SNPs. In conclusion, our study confirms the longterm beneficial effects of high physical training on metabolism and suggests that they are not associated with Acrp30 and/or HMW oligomers changes. Moreover, the correlation of Acrp30 with monocytes in WP athletes could represent a mechanism by which Acrp30 participates in exercise-induced anti-inflammatory functions and/or cardiovascular health. (C) 2016 Elsevier Ltd. All rights reserved.

Human β-defensins play a pivotal role in the innate immune response. Although expressed by and acting at epithelial surfaces, little is known about their specific interaction with epithelial structures. Here, we identify the transmembrane protein CD98 as a cell surface receptor involved in the internalization of human β-defensin 3 (hBD3) in human epithelial A549 cells. CD98 and hBD3 extensively colocalize on the basolateral domain of A549. While verifying their direct binding by fluorescence resonance energy transfer and surface plasmon resonance, we mapped the interaction to CD98 residues 304-414, i.e. to the region known to interact with the proteins of intestinal bacteria during colonic invasion. Treatment of A549 cells with hBD3 dramatically reduces CD98 expression and conversely, knockdown of CD98 expression impairs hBD3 cell surface binding and internalization. Competition for bacterial binding to CD98 and downregulation of CD98 expression may represent novel mechanisms for the antibacterial activity of hBD3 Human β-defensins play a pivotal role in the innate immune response. Although expressed by and acting at epithelial surfaces, little is known about their specific interaction with epithelial structures. Here, we identify the transmembrane protein CD98 as a cell surface receptor involved in the internalization of human β-defensin 3 (hBD3) in human epithelial A549 cells. CD98 and hBD3 extensively colocalize on the basolateral domain of A549. While verifying their direct binding by fluorescence resonance energy transfer and surface plasmon resonance, we mapped the interaction to CD98 residues 304-414, i.e. to the region known to interact with the proteins of intestinal bacteria during colonic invasion. Treatment of A549 cells with hBD3 dramatically reduces CD98 expression and conversely, knockdown of CD98 expression impairs hBD3 cell surface binding and internalization. Competition for bacterial binding to CD98 and downregulation of CD98 expression may represent novel mechanisms for the antibacterial activity of hBD3.