Background: Exposure to arsenic (As) is associated with an increased risk of several cancers as well as cardiovascular disease, and childhood neuro-developmental deficits. Arsenic compounds are weakly mutagenic, alter gene expression and posttranslational histone modifications (PTHMs) in vitro. Methods: Water and urinary As concentrations as well as global levels of histone 3 lysine 9 di-methylation and acetylation (H3K9me2 and H3K9ac), histone 3 lysine 27 tri-methylation and acetylation (H3K27me3 and H3K27ac), histone 3 lysine 18 acetylation (H3K18ac), and histone 3 lysine 4 trimethylation (H3K4me3) were measured in peripheral blood mononuclear cells (PBMC) from a subset of participants (N = 40) of a folate clinical trial in Bangladesh (FACT study). Results: Total urinary As (uAs) was positively correlated with H3K9me2 (r = 0.36, P = 0.02) and inversely with H3K9ac (r = −0.47, P = 0.002). The associations between As and other PTHMs differed in a gender-dependent manner. Water As (wAs) was positively correlated with H3K4me3 (r = 0.45, P = 0.05) and H3K27me3 (r = 0.50, P = 0.03) among females and negatively correlated among males (H3K4me3: r = −0.44, P = 0.05; H3K27me3: r = −0.34, P = 0.14). Conversely, wAs was inversely associated with H3K27ac among females (r = −0.44, P = 0.05) and positively associated among males (r = 0.29, P = 0.21). A similar pattern was observed for H3K18ac (females: r = −0.22, P = 0.36; males: r = 0.27, P = 0.24). Conclusion: Exposure to As is associated with alterations of global PTHMs; gender-specific patterns of association were observed between As exposure and several histone marks. Impact: These findings contribute to the growing body of evidence linking As exposure to epigenetic dysregulation, which may play a role in the pathogenesis of As toxicity. Cancer Epidemiol Biomarkers Prev; 21(12); 2252–60. ©2012 AACR.

Hydrogen sulfide (H2S), the endogenous gaseous signaling molecule alongside nitric oxide and carbon monoxide, is synthesized by multiple enzymes in cardiovascular system. Similar to other gaseous signaling molecules, H2S has demonstrated a variety of biological activities, including anti-oxidative, anti-apoptotic, pro-angiogenic, vasodilating capacities and endothelial nitric oxide synthase modulating activity, and regulates a wide range of pathophysiological processes in cardiovascular disorders. However, the underlying mechanisms by which H2S mediates cardiovascular homeostasis are not fully understood. This review focuses on the recent progress on functional and mechanistic aspects of H2S in the inflammatory and immunoregulatory processes of cardiovascular disorders, importantly myocardial ischemia, heart failure, and atherosclerosis. Moreover, we highlight the challenges for developing H2S-based therapy to modulate the pathological processes in cardiovascular diseases. A better understanding of the biochemical functions of H2S might provide new therapeutic strategies for these cardiovascular diseases.

Angiotensin II (Ang II) causes vascular inflammation, leading to vascular endothelial cell dysfunction, and is associated with the development of cardiovascular diseases. Therefore, interventions in inflammation may contribute to the reduction of cardiovascular diseases. Here, we aim to demonstrate that HDAC4, one of class IIa family histone de-acetylases (HDACs) members, promotes autophagy-dependent vascular inflammation. By loss-of-function approaches, our study provides the first evidence that HDAC4 mediates Ang II-induced vascular inflammation in vitro and in vivo. In response to the Ang II, HDAC4 expression is up-regulated rapidly, with increased autophagic flux and inflammatory mediators in vascular endothelial cells (VECs). In turn, HDAC4 deficiency suppresses activation of autophagy, leading to reduced inflammation in Ang II-induced VECs. Consistently, using autophagy inhibitor or silencing LC3-II also alleviates vascular inflammation. Furthermore, HDAC4 regulates autophagy via facilitating transcription factor forkhead box O3a (FoxO3a) de-acetylation, thereby to increase its transcriptional activity. Loss of HDAC4 in VECs results in inhibition of FoxO3a de-acetylation to block its transcriptional activity, leading to downregulation of the downstream FoxO3a target, and hence reduces autophagy and vascular inflammation. FoxO3a silencing using siRNA approach significantly inhibits activation of autophagy. Finally, knockdown of HDAC4 in Ang II-infused mouse models ameliorates vascular inflammation, suggesting that inhibitor of HDAC4 may be potential therapeutics for vascular diseases associated with inflammation. These results suggest that HDAC4-mediated FoxO3a acetylation regulates Ang II-induced autophagy activation, which in turn plays an essential role in causing vascular inflammation.

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder. Hydrogen sulfide (H2S), the third physiological gasotransmitter, is well recognized as an anti-inflammatory mediator in various inflammatory conditions. Herein, we explored the protective effects of S-propargyl-cysteine (SPRC, also known as ZYZ-802), an endogenous H2S modulator, on RA and determined the underlying mechanisms. In the present study, SPRC concentration-dependently attenuated inflammatory mediator expression, reactive oxidase species generation, and the expression and activity of matrix metalloproteinases (MMP)-9 in interleukin (IL)-1β-induced human rheumatoid fibroblast-like synoviocytes MH7A. In addition, SPRC blocked IL-1β-mediated migration and invasion of MH7A cells. As expected, the protective effects of SPRC were partially abrogated by DL-propargylglycine (PAG, a H2S biosynthesis inhibitor). In vivo study also demonstrated that SPRC treatment markedly ameliorated the severity of RA in adjuvant-induced arthritis rats, and this effect was associated with the inhibition of inflammatory response. We further identified that SPRC remarkably induced heme oxygenase-1 expression associated with the degradation of Kelch-like ECH-associated protein 1 (Keap1) and nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2); this effect was attributed to the sulfhydrylation of the cysteine residue of Keap1. Our data demonstrated for the first time that SPRC, an endogenous H2S modulator, exerted anti-inflammatory properties in RA by upregulating the Nrf2-antioxidant response element (ARE) signaling pathway.