Experimental Autoimmune Myocarditis Hearts Research Articles

Hydrodynamic-Based Delivery of an Interleukin-22-Ig Fusion Gene Ameliorates Experimental Autoimmune Myocarditis in Rats

IL-22 is one of several cytokines with limited homology to IL-10. However, the biological activities of IL-22 are mostly unknown. The purpose of this study was to evaluate the effect of IL-22 on rat experimental autoimmune myocarditis (EAM) and elucidate an aspect of the biological activities of IL-22. Rats were immunized on day 0; IL-22-Ig-treated rats were injected with pCAGGS-IL-22-Ig and control rats with pCAGGS-Ig using hydrodynamics-based gene delivery on day 1 or day 6. IL-22-Ig gene therapy administered on day 1 or day 6 after immunization was effective in controlling EAM as monitored by the heart weight to body weight ratio, and the myocarditis area in rats was sacrificed on day 17. Examination of the expression of IL-22-related genes in purified cells from EAM hearts suggested that IL-22-Ig acting target cells were noncardiomyocytic (NC) noninflammatory cells such as fibroblasts, smooth muscle cells, and endothelial cells. Therefore, we examined the effect of rIL-22 or serum containing IL-22-Ig on the expression of immune-relevant genes in IL-1-stimulated NC cells cultured from EAM hearts. Results showed that the expression of immunologic molecules (PGE synthase, cyclooxygenase-2, MIP-2, MCP-1, IL-6, and cytokine-induced neutrophil chemoattractant-2) in IL-1-stimulated NC cells was significantly decreased by rIL-22 or serum containing IL-22-Ig. EAM was suppressed by hydrodynamics-based delivery of plasmid DNA encoding IL-22-Ig, and the reason for this effectiveness may be that IL-22 suppressed gene expression of PG synthases, IL-6, and chemokines in activated NC noninflammatory cells.

The effect of hydrodynamics-based delivery of an IL-13-Ig fusion gene for experimental autoimmune myocarditis in rats and its possible mechanism

Interleukin (IL)-13 is a pleiotropic cytokine secreted by activated Th2 T lymphocytes. Th1 cytokines are assumed to exacerbate and Th2 cytokines to ameliorate rat experimental autoimmune myocarditis (EAM). Here, we examined the effect of IL-13 on EAM, using a hydrodynamics-based delivery of an IL-13-Ig fusion gene, as well as the possible mechanism of its effect. Rats were immunized on day 0, and IL-13-Ig-treated rats were injected with pCAGGS-IL-13-Ig, and control rats with pCAGGS-Ig, on day 1 or 7. On day 17, the IL-13-Ig gene therapy was effective in controlling EAM as monitored by a decreased heart weight/body weight ratio, by reduced myocarditis and by reduced atrial natriuretic peptide mRNA in the heart, as a heart failure marker. On the basis of IL-13 receptor mRNA expression in separated cells from EAM hearts, we proposed that IL-13-Ig target cells were CD11b(+) cells and non-cardiomyocytic noninflammatory (NCNI) cells, such as fibroblasts, smooth muscle or endothelial cells. IL-13-Ig inhibited expression of the genes for prostaglandin E synthase, cyclooxygenase-2, inducible nitric oxide synthase, IL-1beta and TNF-alpha in cultivated cells from EAM hearts, while it enhanced expression of the IL-1 receptor antagonist gene. We conclude that IL-13-Ig ameliorates EAM and suppose that its effectiveness may be due to the influence on these immunologic molecules in CD11b(+) and NCNI cells.

Effect of Hydrodynamics-Based Gene Delivery of Plasmid DNA Encoding Interleukin-1 Receptor Antagonist-Ig for Treatment of Rat Autoimmune Myocarditis

Interleukin-1 (IL-1) is a powerful and important cytokine in myocarditis. The purpose of this study was to evaluate the effect and possible mechanism of hydrodynamics-based delivery of the IL-1 receptor antagonist (IL-1RA)-immunoglobulin (Ig) gene for treatment of rat experimental autoimmune myocarditis (EAM). On the day after immunization, rats were transfected with either pCAGGS encoding IL-1RA-Ig or pCAGGS encoding Ig alone. On day 17, IL-1RA-Ig gene therapy was effective in controlling EAM, as monitored by a decreased ratio of heart weight to body weight, reduced myocarditis areas, reduced gene expression of atrial natriuretic peptide in hearts, and improved cardiac function in echocardiographic and hemodynamic parameters. Examination of the expression of IL-1-related genes in purified cells from EAM hearts suggested that ectopic IL-1RA-Ig-acting target cells were alphabetaT cells and noncardiomyocytic noninflammatory cells such as fibroblasts, smooth muscle cells, and endothelial cells. Therefore, we examined the effect of serum containing IL-1RA-Ig on the expression of immune-relevant genes within noncardiomyocytic cells cultured from EAM hearts or concanavalin A-stimulated lymphocytes derived from lymph nodes in EAM-affected rats. The expression of immunologic molecules (prostaglandin E synthase, cyclooxygenase-2, and IL-1beta) in cultivated noncardiomyocytic cells and Th1 cytokines (IL-2 and IFN-gamma) in lymphocytes was significantly decreased by the serum containing IL-1RA-Ig. EAM was suppressed by hydrodynamics-based delivery of plasmid DNA encoding IL-1RA-Ig. In addition, IL-1RA-Ig suppressed gene expression of prostaglandin synthases and IL-1 in noncardiomyocytic cells and Th1 cytokines in lymphocytes.