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Sepsis is a major cause of mortality in intensive care units, which results from a severely dysregulated inflammatory response that ultimately leads to organ failure. While antibiotics can help in the early stages, effective strategies to curtail inflammation remain limited. The high mobility group (HMG) proteins are chromosomal proteins with important roles in regulating gene transcription. While HMGB1 has been shown to play a role in sepsis, the role of other family members including HMGXB4 remains unknown. We found that expression of HMGXB4 is strongly induced in response to lipopolysaccharide (LPS)-elicited inflammation in murine peritoneal macrophages. Genetic deletion of Hmgxb4 protected against LPS-induced lung injury and lethality and cecal ligation and puncture (CLP)-induced lethality in mice, and attenuated LPSinduced proinflammatory gene expression in culturedmacrophages. By integrating genome-wide transcriptome profiling and a publicly available ChIP-seq dataset, we identified HMGXB4 as a transcriptional activator that regulates the expression of the proinflammatory gene, Nos2 (inducible nitric oxide synthase 2) by binding to its promoter region, leading to NOS2 induction and excessive NO production and tissue damage. Similar to Hmgxb4 ablation in mice, administration of a pharmacological inhibitor of NOS2 robustly decreased LPS-induced pulmonary vascular permeability and lethality in mice. Additionally, we identified the cell adhesion molecule, ICAM1, as a target of HMGXB4 in endothelial cells that facilitates inflammation by promoting monocyte attachment. In summary, our study reveals a critical role of HMGXB4 in exacerbating endotoxemia via transcriptional induction of Nos2 and Icam1 gene expression and thus targeting HMGXB4 may be an effective therapeutic strategy for the treatment of sepsis. [ABSTRACT FROM AUTHOR]

ABSTRACT This study assessed the potential hepatoprotective effect of telmisartan (TLM), a selective angiotensin II type 1 (AT1) receptor blocker, on carbon tetrachloride (CCl4)-induced acute hepatotoxity in rats. Intraperitoneal injection of male Wistar rats with CCl4 1 mL kg−1, 1:1 mixture with corn oil for 3 days increased serum alanine transaminase, aspartate transaminase, and alkaline phosphatase activities as well as total bilirubin, triglycerides and total cholesterol levels. This is in addition to the disrupted histological architecture in the CCl4 group. Rats receiving CCl4 and co-treated with TLM (3 and 10 mg kg−1, orally) showed ameliorated serum biochemical and histological changes almost to the control level. Nevertheless, rats treated with TLM (1 mg kg−1) didn't show any significant changes compared to CCl4 intoxicated group. In addition, TLM rectified oxidative status disrupted by CCl4 intoxication. Interestingly, TLM protected against CCl4-induced expressions of nuclear factor-κB, inducible nitric oxide synthase and cyclooxygenase-II, in a dose related manner. Moreover, TLM (3 and 10 mg kg−1) significantly modified CCl4-induced elevation in tumor necrosis factor-α and nitric oxide levels. Furthermore, TLM showed a marked decline in CD68+ cells stained areas and reduced activity of myeloperoxidase enzyme compared to CCl4-intoxicated group. In conclusion, both doses of TLM (3 and 10 mg kg−1) showed significant hepato-protective effects. However, TLM at a dose of 10 mg kg−1 didn't show significant efficacy above 3 mg kg−1 which is nearly equivalent to the human anti-hypertensive dose of 40 mg. Thus, may be effective in guarding against several hepatic complications due to its antioxidant and anti-inflammatory activities. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 359-370, 2017. [ABSTRACT FROM AUTHOR]

Visceral adipose tissue (VAT) inflammation and metabolic dysregulation are key components of obesity-induced metabolic disease. Upregulated arginase, a ureahydrolase enzyme with two isoforms (A1-cytosolic and A2-mitochondrial), is implicated in pathologies associated with obesity and diabetes. This study examined A2 involvement in obesity-associated metabolic and vascular disorders. WT and globally deleted A2(−/−) or A1(+/−) mice were fed either a high fat/high sucrose (HFHS) diet or normal diet (ND) for 16 weeks. Increases in body and VAT weight of HFHS-fed WT mice were abrogated in A2−/−, but not A1+/−, mice. Additionally, A2−/− HFHS-fed mice exhibited higher energy expenditure, lower blood glucose, and insulin levels compared to WT HFHS mice. VAT and adipocytes from WT HFHS fed mice showed greater A2 expression and adipocyte size and reduced expression of PGC-1α, PPAR-γ, and adiponectin. A2 deletion blunted these effects, increased levels of active AMPK-α, and upregulated genes involved in fatty acid metabolism. A2 deletion prevented HFHS-induced VAT collagen deposition and inflammation, which are involved in adipocyte metabolic dysfunction. Endothelium-dependent vasorelaxation, impaired by HFHS diet, was significantly preserved in A2−/− mice, but more prominently maintained in A1+/− mice. In summary, A2 is critically involved in HFHS-induced VAT inflammation and metabolic dysfunction. [ABSTRACT FROM AUTHOR]

Obesity has reached epidemic proportions and its prevalence is climbing. Obesity is characterized by hypertrophied adipocytes with a dysregulated adipokine secretion profile, increased recruitment of inflammatory cells, and impaired metabolic homeostasis that eventually results in the development of systemic insulin resistance, a phenotype of type 2 diabetes. Nitric oxide synthase (NOS) is an enzyme that converts L-arginine to nitric oxide (NO), which functions to maintain vascular and adipocyte homeostasis. Arginase is a ureohydrolase enzyme that competes with NOS for L-arginine. Arginase activity/expression is upregulated in obesity, which results in diminished bioavailability of NO, impairing both adipocyte and vascular endothelial cell function. Given the emerging role of NO in the regulation of adipocyte physiology and metabolic capacity, this review explores the interplay between arginase and NO, and their effect on the development of metabolic disorders, cardiovascular diseases, and mitochondrial dysfunction in obesity. A comprehensive understanding of the mechanisms involved in the development of obesity-induced metabolic and vascular dysfunction is necessary for the identification of more effective and tailored therapeutic avenues for their prevention and treatment.