Intramuscular transfer of naked calcitonin gene‐related peptide gene prevents autoimmune diabetes induced by multiple low‐dose streptozotocin in C57BL mice

Abstract

The imbalance of Th1/Th2 subsets is an important pathogenic mechanism for insulindependent diabetes mellitus (IDDM). Calcitonin gene-related peptide (CGRP) has been found to play important roles in the regulation of T lymphocytes. We hypothesize that exogenous CGRP administration during insulitis may modulate the balance of Th lymphocytes, thereby providing a therapeutic intervention for IDDM. We established CGRP gene transfer by naked plasmid injection into the skeletal muscles with electroporation enhancement. The effect of CGRP gene transfer on pathogenesis of IDDM was observed in autoimmune diabetic C57BL mice induced by multiple low-dose streptozotocin (MLDS) administration. The treatment significantly decreased morbidity of diabetes, ameliorated hyperglycemia and insulin deficiency, and inhibited lymphocyte infiltration into the islets, indicating the protection of g cells against autoimmune destruction. CGRP gene transfer significantly inhibited T cell proliferation and secretion of the Th1 cytokine IFN-+ , increased the level of the Th2 cytokine IL-10, but had no effect on IL-4 and TGF-g 1 secretion. CGRP gene transfer also decreased IL-12 and IFN-+ levels in peritoneal effusion. Our results demonstrate that CGRP gene transfer selectively suppresses the pro-inflammatory Th1 subsets and promote antiinflammatory Th2 subsets, resulting in amelioration of g cell destruction and reduction of IDDM occurrence in mice with MLDS-induced diabetes.

Endogenous Calcitonin Gene-related Peptide Protects Human Alveolar Epithelial Cells through Protein Kinase Cϵ and Heat Shock Protein

“…As a widely existing neuropeptide, calcitonin gene-related peptide (CGRP) has broad regulatory effects throughout the body, especially in the cardiovascular and respiratory system (6,7). In addition to its well known effects on vasodilation (8), immunomodulation (9), and repression of vascular smooth muscle cell proliferation (10,11), CGRP has also been implicated to have a protective role in preconditioning of isolated rat hearts and intestines (12,13). Regarding the lung, both CGRP and its receptor are expressed in type II alveolar epithelial cells.…”

Calcitonin gene-related peptide inhibits interleukin-1 ?-induced interleukin-8 secretion in human type II alveolar epithelial cells

“…We have demonstrated that CGRP can attenuate multiple low-dose streptozotocin-induced insulitis and reduce the occurrence of diabetes in mice [12] . As well as this, in vitro experiments have found that lymphocyte-derived CGRP can inhibit Con A-induced proliferation and IL-2 production in rat thymocytes in an autocrine/paracrine mode [22] .…”

“…Stable transfection of CGRP gene into A549 cells A pcDNA3.1 plasmid containing human CGRP cDNA was constructed as previously described [12] and transferred to the A549 cells with the use of Lipofectin (Invitrogen, Carlsbad, CA, USA). After transfection, the cells were cultured with G418 (800 mg·L -1 ) for 4 d, and a stably transfected cell line was selected by subculturing the cells from a monoclone.…”

Intramuscular gene transfer of CGRP inhibits neointimal hyperplasia after balloon injury in the rat abdominal aorta

“…The plasmid pcDNA3.1 containing the hCGRP gene was constructed in our laboratory as previously described (27). Plasmids were transferred into primary cultured VSMCs with the use of the calcium phosphate method to evaluate hCGRP expression in eukaryotic cells.…”

“…It is considered the most potent intrinsic vasodilator in humans (3). Our recent studies (18,27) and that of others (19) have revealed several new cell-protective roles of CGRP, including modulating immunoresponses, mediating ischemic preconditioning, and inhibiting VSMC proliferation. In particular, we have shown that CGRP and nitric oxide (NO) exhibit synergistic effects in inhibiting VSMC proliferation (32) and that NO also mediates a CGRP-induced vasorelaxant effect (33).…”