Prenatal inflammation exposure-programmed hypertension exhibits multi-generational inheritance via disrupting DNA methylome.

The multi-generation heredity trait of hypertension in human has been reported, but the molecular mechanisms underlying multi-generational inheritance of hypertension remain obscure. Recent evidence shows that prenatal inflammatory exposure (PIE) results in increased incidence of cardiovascular diseases, including hypertension. In this study we investigated whether and how PIE contributed to multi-generational inheritance of hypertension in rats. PIE was induced in pregnant rats by intraperitoneal injection of LPS or Poly (I:C) either once on gestational day 10.5 (transient stimulation, T) or three times on gestational day 8.5, 10.5, and 12.5 (persistent stimulation, P). Male offspring was chosen to study the paternal inheritance. We showed that PIE, irrespectively induced by LPS or Poly (I:C) stimulation during pregnancy, resulted in multi-generational inheritance of significantly increased blood pressure in rat descendants, and that prenatal LPS exposure led to vascular remodeling and vasoconstrictor dysfunction in both thoracic aorta and superior mesenteric artery of adult F2 offspring. Furthermore, we revealed that PIE resulted in global alteration of DNA methylome in thoracic aorta of F2 offspring. Specifically, PIE led to the DNA hypomethylation of G beta gamma (Gßγ) signaling genes in both the F1 sperm and the F2 thoracic aorta, and activation of PI3K/Akt signaling was implicated in the pathologic changes and dysregulated vascular tone of aortic tissue in F2 LPS-P offspring. Our data demonstrate that PIE reprogrammed DNA methylome of cells from the germline/mature gametes contributes to the development of hypertension in F2 PIE offspring. This study broadens the current knowledge regarding the multi-generation effect of the cumulative early life environmental factors on the development of hypertension.

α-Galactosylceramide and its analog OCH differentially affect the pathogenesis of ISO-induced cardiac injury in mice.

Immunotherapies for cancers may cause severe and life-threatening cardiotoxicities. The underlying mechanisms are complex and largely elusive. Currently, there are several ongoing clinical trials based on the use of activated invariant natural killer T (iNKT) cells. The potential cardiotoxicity commonly associated with this particular immunotherapy has yet been carefully evaluated. The present study aims to determine the effect of activated iNKT cells on normal and ß-adrenergic agonist (isoproterenol, ISO)-stimulated hearts. Mice were treated with iNKT stimulants, α-galactosylceramide (αGC) or its analog OCH, respectively, to determine their effect on ISO-induced cardiac injury. We showed that administration of αGC (activating both T helper type 1 (Th1)- and T helper type 2 (Th2)-liked iNKT cells) significantly accelerated the progressive cardiac injury, leading to enhanced cardiac hypertrophy and cardiac fibrosis with prominent increases in collagen deposition and TGF-ß1, IL-6, and alpha smooth muscle actin expression. In contrast to αGC, OCH (mainly activating Th2-liked iNKT cells) significantly attenuated the progression of cardiac injury and cardiac inflammation induced by repeated infusion of ISO. Flow cytometry analysis revealed that αGC promoted inflammatory macrophage infiltration in the heart, while OCH was able to restrain the infiltration. In vitro coculture of αGC- or OCH-pretreated primary peritoneal macrophages with primary cardiac fibroblasts confirmed the profibrotic effect of αGC and the antifibrotic effect of OCH. Our results demonstrate that activating both Th1- and Th2-liked iNKT cells is cardiotoxic, while activating Th2-liked iNKT cells is likely cardiac protective, which has implied key differences among subpopulations of iNKT cells in their response to cardiac pathological stimulation.

Bmp2 regulates the interaction between EPDCs and myocytes in cardiac OFT.

Epicardium-derived cells (EPDCs) can migrate into the myocardium, giving rise to several types of cell which are indispensable to compact myocardium and inducing normal myocardial development. Subepicardium accumulates bone morphogenetic proteins (Bmps), which can release into myocardium further. It has been shown that reduced Bmp-mediated signaling in a novel neural crest derivative in the epicardium reduced the cardiomyocyte proliferative activity in the developing myocardium. Furthermore, studies have demonstrated that cardiomyocytes can develop in proepicardial organ (PEO) explant cultures after stimulation with bone morphogenetic protein (Bmp2). We present a hypothesis that Bmp2 regulates the interaction between EPDCs and cardiomyocyte in the developing outflow tract (OFT). Our previous empirical data also shows that Bmp2 is expressed in the myocardial cell in the OFT at embryonic day (E) 14.5 in wild-type mice, and expression of Bmp2 in Cx43α1 knockout (KO) OFT was delayed for 1day. Further validation of this hypothesis will provide additional insight of the molecular mechanism of myocardium maturation.