RESUMEN
Our goal was to investigate the effect of heat shock on human monocyte-derived dendritic cells (DCs) and to dissect the role of thermosensitive transient receptor potential (TRP) channels in the process. We provide evidence that a short heat shock challenge (43 °C) decreased the endocytotic activity of the DCs and that this effect could be alleviated by the RNAi-mediated knockdown of TRPV2 but, importantly, not by the pharmacological (antagonists) or molecular (RNAi) suppression of TRPV1 and TRPV4 activities/levels. Likewise, the heat shock-induced robust membrane currents were selectively and markedly inhibited by TRPV2 "silencing" whereas modulation of TRPV1 and TRPV4 activities, again, had no effect. These intriguing data introduce TRPV2-coupled signaling as a key player in mediating the cellular actions of heat shock on DCs.
Asunto(s)
Células Dendríticas/citología , Células Dendríticas/metabolismo , Endocitosis , Respuesta al Choque Térmico , Monocitos/citología , Canales Catiónicos TRPV/metabolismo , Membrana Celular/metabolismo , Fenómenos Electrofisiológicos , Regulación de la Expresión Génica , Humanos , Canales Catiónicos TRPV/genética , Factores de TiempoRESUMEN
OBJECTIVES: Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa. Its etiology is still unclear. Neurogenic components might contribute to the inflammatory process. The oral mucosa is richly innervated by sensory fibers. Mediators secreted by inflammatory cells activate sensory nerves via transient receptor potential vanilloid receptor 1 (TRPV1) and lead to the release of neuropeptides. So far, TRPV1 receptor expression was detected on neurons. Only recently, TRPV1 receptors were identified in nonneuronal tissues. The aim of the present study was to detect the presence of TRPV1 receptors and peripheral expression of receptor mRNA in normal oral mucosa and mucous membranes from OLP patients. METHODS: Presence of TRPV1 receptor proteins in the mucosal tissue was assessed by immunohistochemistry. Expression of TRPV1 receptor mRNA was determined by quantitative RT-PCR. RESULTS: We provided qualitative and quantitative immunohistochemical evidence that TRPV1 receptors are present in normal human oral mucosa and that their expression is increased in OLP. The number of immunopositive cells was elevated in the epithelium, and vascular endothelial cells, lymphocytes and fibroblasts of the subepithelium were also labeled in samples obtained from OLP patients. The local expression of nonneuronal TRPV1 receptors was proven at mRNA level using quantitative real-time RT-PCR. CONCLUSIONS: Since the number of TRPV1 receptor-positive nonneural cells is increased in inflammatory conditions, we hypothesize that TRPV1-receptor-mediated processes might play role in the pathogenesis of OLP.
Asunto(s)
Inflamación/metabolismo , Liquen Plano Oral/metabolismo , Mucosa Bucal/metabolismo , Canales Catiónicos TRPV/metabolismo , Adulto , Células Endoteliales/metabolismo , Células Epiteliales/metabolismo , Femenino , Fibroblastos/metabolismo , Regulación de la Expresión Génica/fisiología , Humanos , Inmunohistoquímica , Inflamación/genética , Inflamación/fisiopatología , Liquen Plano Oral/genética , Liquen Plano Oral/fisiopatología , Linfocitos/metabolismo , Masculino , Persona de Mediana Edad , Mucosa Bucal/patología , Mucosa Bucal/fisiopatología , Nociceptores/metabolismo , ARN Mensajero/análisis , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Receptoras Sensoriales/metabolismo , Canales Catiónicos TRPV/genética , Regulación hacia Arriba/fisiologíaRESUMEN
In this study, we have investigated the effects of insulin-like growth factor-I (IGF-I) on cellular responses of primary human skeletal muscle cells and mouse C2C12 myoblasts. In human muscle, IGF-I stimulated proliferation and fusion of the cells and the expression of the differentiation marker desmin. These effects were completely inhibited by Rottlerin, the inhibitor of the protein kinase C (PKC)delta, but were not affected by the inhibition of the mitogen-activated protein kinase (MAPK) or the phosphatidylinositide 3-kinase (PI-3K) pathways. Furthermore, IGF-I initiated the selective translocation of PKCdelta to the nucleus. In C2C12 myoblasts, the growth-promoting effects of IGF-I were abrogated by inhibition of PKCdelta, but not by the inhibition of the PI-3K system. However, in contrast to the human data, the MAPK inhibitor PD098059 partially (yet significantly) also inhibited the action of IGF-I and, furthermore, IGF-I induced phosphorylation of the MAPK Erk-1/2. In addition, overexpression of constitutively active form of PKCdelta in C2C12 cells fully mimicked, whereas overexpression of kinase inactive mutant of the isoform prevented the action of IGF-I. Finally, the inhibition of PKCdelta suspended the IGF-I-induced phosphorylation of Erk-1/2 and, moreover, the inhibition of the MAPK pathway partially (yet significantly) inhibited the accelerated growth of C2C12 cells overexpressing PKCdelta. Taken together, these results demonstrate a novel, central and exclusive involvement of PKCdelta in mediating the action of IGF-I on human skeletal muscle cells, with an additional yet PKCdelta-dependent contribution of the MAPK pathway on C2C12 myoblasts.