Endothelin-2/Vasoactive Intestinal Contractor: Regulation of Expression via Reactive Oxygen Species Induced by CoCl 2

This paper reviews the local hormone endothelin-2 (ET-2), or vasoactive intestinal contractor (VIC), a member of the vasoconstrictor ET peptide family, where ET-2 is the human orthologous peptide of the murine VIC. While ET-2/VIC gene expression has been observed in some normal tissues, ET-2 recently has been reported to act as a tumor marker and as a hypoxia-induced autocrine survival factor in tumor cells. A recently published study reported that the hypoxic mimetic agent CoCl2 at 200 µM increased expression of the ET-2/VIC gene, decreased expression of the ET-1 gene, and induced intracellular reactive oxygen species (ROS) increase and neurite outgrowth in neuronal model PC12 cells. The ROS was generated by addition of CoCl2 to the culture medium, and the CoCl2-induced effects were completely inhibited by the antioxidant N-acetyl cysteine. Furthermore, interleukin-6 (IL-6) gene expression was up-regulated upon the differentiation induced by CoCl2. These results suggest that expression of ET-2/VIC and ET-1 mediated by CoCl2-induced ROS may be associated with neuronal differentiation through the regulation of IL-6 expression. CoCl2 acts as a pro-oxidant, as do Fe(II, III) and Cu(II). However, some biological activities have been reported for CoCl2 that have not been observed for other metal salts such as FeCl3, CuSO4, and NiCl2. The characteristic actions of CoCl2 may be associated with the differentiation of PC12 cells. Further elucidation of the mechanism of neurite outgrowth and regulation of ET-2/VIC expression by CoCl2 may lead to the development of treatments for neuronal disorders

Endothelin system in intestinal villi: A possible role of endothelin-2/vasoactive intestinal contractor in the maintenance of intestinal architecture

The endothelin system consists of three ligands (ET-1, ET-2 and ET-3) and at least two receptors (ETA and ETB). In mice ET-2 counterpart is a peptide originally called " vasoactive intestinal contractor" (VIC) for this reason, this peptide is frequently named ET-2/VIC. In intestinal villi, fibroblasts-like cells express endothelin's receptors and response to ET-1 and ET-3 peptides, changing their cellular shape. Several functions have been attributed to these peptides in the " architecture" maintenance of intestinal villi acting over sub-epithelial fibroblasts. Despite this, ET-2/VIC has not been analyzed in depth. In this work we show the intestine gene expression and immunolocalization of ET-1, ET-2 and the ETA and ETB receptors from duodenum to rectus and in the villus-crypt axis in mice, allowing a complete analysis of their functions. While ET-1 is expressed uniformly, ET-2 had a particular distribution, being higher at the bottom of the villi of duodenum, ileum and jejunum and reverting this pattern in the crypts of colon and rectus, where the higher expression was at the top. We postulated that ET-2 would act in a cooperative manner with ET-1, giving to the villus the straight enough to withstand mechanical stress.Fil: Bianchi, Mariana. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Adur, Javier Fernando. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Takizawa, Satoshi. Institute for Biological Resources and Functions; JapónFil: Saida, Kaname. Soka University; Japón. Institute for Biological Resources and Functions; JapónFil: Casco, Victor Hugo. Universidad Nacional de Entre Ríos. Facultad de Ingeniería. Departamento de Biología. Laboratorio de Microscopía; Argentin

Effects of vasoactive intestinal contractor (VIC) and endothelin on intracellular calcium level in neuroblastoma NG108-15 cells

AbstractEffects on [Ca2+]i levels of endothelin-1 (ET) and vasoactive intestinal contractor peptide (VIC), which is a novel member of the endothelin family, were examined in fura 2-loaded neuroblastoma NG108-15 cells. VIC was found to be a very effective stimulus for intracellular Ca2+ mobilization and to be more potent than ET. Intracellular calcium response to sequential addition of two stimulants exhibited the homologous desensitization of either ET or VIC, but no heterologous desensitization between ET and VIC. This indicates evidence suggesting that these two peptides act through distinct receptors

Endothelin-2/vasoactive intestinal contractor: regulation of expression via reactive oxygen species induced by CoCl2, and biological activities including neurite outgrowth in PC12 cells. Sci World J

This paper reviews the local hormone endothelin-2 (ET-2), or vasoactive intestinal contractor (VIC), a member of the vasoconstrictor ET peptide family, where ET-2 is the human orthologous peptide of the murine VIC. While ET-2/VIC gene expression has been observed in some normal tissues, ET-2 recently has been reported to act as a tumor marker and as a hypoxia-induced autocrine survival factor in tumor cells. A recently published study reported that the hypoxic mimetic agent CoCl 2 at 200 μM increased expression of the ET-2/VIC gene, decreased expression of the ET-1 gene, and induced intracellular reactive oxygen species (ROS) increase and neurite outgrowth in neuronal model PC12 cells. The ROS was generated by addition of CoCl 2 to the culture medium, and the CoCl 2 -induced effects were completely inhibited by the antioxidant N-acetyl cysteine. Furthermore, interleukin-6 (IL-6) gene expression was up-regulated on the differentiation induced by CoCl 2 . These results suggest that expression of ET-2/VIC and ET-1 mediated by CoCl 2 -induced ROS may be associated with neuronal differentiation through the regulation of IL-6 expression. CoCl 2 acts as a pro-oxidant, as do Fe(II, III) and Cu(II). However, some biological activities have been reported for CoCl 2 that have not been observed for other metal salts such as FeCl 3 , CuSO 4 , and NiCl 2 . The characteristic actions of CoCl 2 may be associated with the differentiation of PC12 cells. Further elucidation of the mechanism of neurite outgrowth and regulation of ET-2/VIC expression by CoCl 2 may lead to the development of treatments for neuronal disorders. KEYWORDS: cobalt chloride (CoCl 2 ), endothelin-1 (ET-1), endothelin-2 (ET-2), hypoxia, neurite outgrowth, PC12, reactive oxygen species (ROS), vasoactive intestinal contractor (VIC) 176 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 INTRODUCTION Endothelin-1 (ET-1), a vasoconstrictor peptide produced by vascular endothelial cells 177 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 DISCOVERY, DISTRIBUTION, AND EXPRESSION OF ET-2 AND VIC ET-2 and VIC were discovered independently in the late 1980s through analysis of human In addition to PCR gene expression analysis, peptide levels of ET family ligands by antibody or reverse-phase HPLC BIOLOGICAL ACTIONS OF ET-2/VIC The biosynthetic pathway for VIC was proposed based on DNA cloning analysis Mice with ET system deficiencies have been developed and reported. ET-1 homozygous knockout mice die at birth and possess craniofacial abnormalities such as deformed thyroid cartilage, missing hyoid and a large part of the tongue, and cleft palate [28], as well as malformations of the aortic arch and septal ventricular defect [29]. Elevated blood pressure was observed in ET-1 heterozygous mice [28]. Mice deficient in ET-A also showed craniofacial deformities and defects in the cardiovascular outflow tract caused, respectively, by disruption of cephalic and cardiac neural crest development [30]. Mice deficient in or showed a distension of the intestine (megacolon) and coat color spotting related to deficient development of enteric ganglion neurons and epidermal and choroidal melanocytes, respectively. These results indicate that ET peptides and receptors are essential components in the development of normal tissue and ontogeny. The generation of an ET-2/VIC knockout mouse has not yet been reported. Thus, the essential physiological functions of ET-2/VIC remain unknown, although a number of biological actions of ET-2/VIC have been reported. The relative vasoconstrictor activities for ETs (in anesthetized rats in vivo) were reported to be ET-2 > ET-1 > ET-3[2]. ET-2/VIC also exhibits other biological activities such as the induction of contraction in mouse ileum [33] and acetylcholine release in guinea-pig ileum [34,35], the stimulation of an increase in intracellular Ca 2+ in Swiss 3T3 cells [27,34] and in mouse NG108-15 neuroblastoma cells [36,37], the 178 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 accumulation of diacylglycerol in NG108-15 cells and vascular smooth-muscle cells [37], and the production of both vasodilation and vasoconstriction in the systemic vascular bed and biphasic changes in pulmonary vascular resistance in the cat [38]. ET-2/VIC gene expression also increases significantly during embryonic development Hypoxia is generally thought to diminish the effects of treatments against tumors such as irradiation and chemical therapy. Moreover, hypoxia is reported to stimulate the invasiveness of MDA-MB-231 breast carcinoma cells NEURITE OUTGROWTH AND REGULATION OF ET-2/VIC INDUCED BY COCL 2 IN PC12 CELLS[21] Neurite outgrowth in rat cerebellar macroneurons is enhanced by ethanol [39], which acts as a hypoxia-inducible factor-1α (HIF-1α) activator [40]. Thus, hypoxia or hypoxia-inducible agents may induce neurite outgrowth in neuronal cells. Moreover, it has been suggested that neuronal differentiation of P19 mouse embryonal carcinoma cells is associated with the ET system [41]. However, it is unknown 179 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 whether ET-2/VIC, one of the hypoxia-related genes Up-regulation of ET-1 gene expression has been demonstrated in primary rat cardiomyocytes treated with CoCl 2 at 100 μM [43] and in lung tissue of mice exposed to hypoxia [44], whereas up-regulation of the ET-1 gene in PC12 cells treated with CoCl 2 was not observed Not only nerve growth factor (NGF), but also IL-6, have been known to induce neuronal differentiation in PC12 [46]. Irradiation was reported to induce neuronal differentiation in PC12 cells through the regulation of . Moreover, IL-6 also was reported to protect PC12 against cell death [48]. CoCl 2 at 200 μM up-regulates IL-6 gene expression in the differentiation of PC12 cells. Furthermore, although acetylcholinesterase activity was reported to increase in the differentiation of PC12 cells induced by NGF ET-2/VIC was suggested to be an important factor in the regulation of both neuronal differentiation and neuronal cell death in the nervous system. ET-A and ET-B genes were expressed in PC12 cells. Which of these receptors mediates the induction of neuronal differentiation or neuronal cell death through the 180 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 regulation of ET-2/VIC and ET-1 in PC12 cells is not yet known. The detailed mechanisms of mediation through ET receptors deserve further study. Further elucidation of the mechanisms of neurite outgrowth and regulation of ET-2/VIC expression induced by CoCl 2 may lead to the development of treatments against neuronal disorders such as Alzheimer's and Parkinson's diseases. REACTIVE OXYGEN SPECIES (ROS) GENERATION BY COCL 2 IN THE DIFFERENTIATION OF PC12 CELLS[21] It has been reported that intracellular ROS are responsible for the neuronal differentiation of PC12 cells induced by NGF ROS derived from NADPH oxidase have been reported to be involved in NGF-induced differentiation in PC12 cells The relationship between ET-1 regulation and ROS generation in cultured cells has been reported in several studies. Expression of ET-1 gene or peptide decreases with the addition of H 2 O 2 to the medium or 181 Kotake-Nara and Saida: Biological activities of ET-2/VIC TheScientificWorldJOURNAL (2006) 6, 176-186 with the enhancement of intracellular ROS levels in bovine carotid artery endothelial cells Although NiCl 2 is known as a hypoxia mimetic agent, this divalent cation salt failed to induce neurite outgrowth in PC12 cells Co(II) acts as a pro-oxidant, as does Fe(II, III) and Cu(II), and promotes lipid peroxidation. In general, these metals have been thought to produce cytotoxic activity through the stimulation of ROS generation and to induce cell death at high concentrations. In fact, CoCl 2 at 500 μM previously has been reported to induce apoptosis in PC12 cells through RO