Abstract-Cardiac remodeling is associated with hypertrophy and fibrosis processes, which may depend on the activity of matrix metalloproteinases (MMPs) and "a disintegrin and metalloproteinases" (ADAMs). We investigated whether ADAM-17 (tumor necrosis factor-␣-converting enzyme [TACE]) plays a role in agonist-induced cardiac remodeling and the relationships established among TACE, MMP-2, and ADAM-12. We targeted TACE in rodent models of spontaneous and agonist-induced hypertension using RNA interference combined with quantitative RT-PCR, activity determinations, and functional studies. Treatment of spontaneously hypertensive rats with previously validated TACE small-interfering RNA for 28 days resulted in systemic knockdown of TACE expression. TACE knockdown effectively stopped the development of cardiac hypertrophy. Mice receiving angiotensin II (1.4 mg/kg per day for 12 days) exhibited cardiac hypertrophy, as well as fibrosis, which was associated with elevated myocardial expression of molecular markers of hypertrophy (␣-skeletal actin, ␤-myosin heavy chain, and brain natriuretic peptide) and fibrosis (collagen types I and III and fibronectin), as well as MMP-2 and ADAM-12. Treatment with TACE small-interfering RNA (but not with PBS or luciferase small-interfering RNA) inhibited TACE expression, thus preventing angiotensin II-induced cardiac hypertrophy and fibrosis. Moreover, knockdown of TACE inhibited angiotensin II-induced overexpression of markers of myocardial hypertrophy and fibrosis, as well as ADAM-12 and MMP-2. These findings provide the first in vivo evidence that agonist-induced cardiac hypertrophy and fibrosis processes are signaled through TACE, which acts through novel pathways involving transcriptional regulation of ADAM-12 and MMP-2. Targeting TACE has potential therapeutic importance for modulating agonist-induced cardiac remodeling. Key Words: cardiac hypertrophy Ⅲ hypertension Ⅲ metalloproteinase Ⅲ ADAM-17/TACE Ⅲ Gq protein-coupled receptor agonist Ⅲ RNA interference C ardiac remodeling is a major hallmark of hypertensive disorders and is associated with the development of cardiac hypertrophy (ie, an increase in cell size of individual cardiomyocytes), which causes thickening of the myocardium. Although initially compensatory, sustained hypertrophic growth is pathological, in part, because of its association with the development of fibrosis (ie, increased synthesis and deposition of extracellular matrix proteins), which disrupts the normal structure and contractile properties of the myocardium. 1 Pathological cardiac remodeling is, thus, detrimental for cardiac function and may cause cardiac dysfunction, myocardial stiffness, and increased risk of heart failure, sudden death, and stroke. 2-5 However, it remains unclear how and why such apparently distinct processes as cardiac hypertrophy and fibrosis develop with hypertension and whether pressure overload in hypertension is causal.Our laboratory is investigating the general hypothesis that cardiac remodeling may be associated with hypertens...

Ras association domain family protein 1A (RASSF1A) is a tumor suppressor gene silenced in cancer. Here we report that RASSF1A is a novel regulator of intestinal inflammation as Rassf1a+/−, Rassf1a−/− and an intestinal epithelial cell specific knockout mouse (Rassf1a IEC-KO) rapidly became sick following dextran sulphate sodium (DSS) administration, a chemical inducer of colitis. Rassf1a knockout mice displayed clinical symptoms of inflammatory bowel disease including: increased intestinal permeability, enhanced cytokine/chemokine production, elevated nuclear factor of kappa light polypeptide gene enhancer in B-cells (NFκB) activity, elevated colonic cell death and epithelial cell injury. Furthermore, epithelial restitution/repair was inhibited in DSS-treated Rassf1a−/− mice with reduction of several makers of proliferation including Yes associated protein (YAP)-driven proliferation. Surprisingly, tyrosine phosphorylation of YAP was detected which coincided with increased nuclear p73 association, Bax-driven epithelial cell death and p53 accumulation resulting in enhanced apoptosis and poor survival of DSS-treated Rassf1a knockout mice. We can inhibit these events and promote the survival of DSS-treated Rassf1a knockout mice with intraperitoneal injection of the c-Abl and c-Abl related protein tyrosine kinase inhibitor, imatinib/gleevec. However, p53 accumulation was not inhibited by imatinib/gleevec in the Rassf1a−/− background which revealed the importance of p53-dependent cell death during intestinal inflammation. These observations suggest that tyrosine phosphorylation of YAP (to drive p73 association and up-regulation of pro-apoptotic genes such as Bax) and accumulation of p53 are consequences of inflammation-induced injury in DSS-treated Rassf1a−/− mice. Mechanistically, we can detect robust associations of RASSF1A with membrane proximal Toll-like receptor (TLR) components to suggest that RASSF1A may function to interfere and restrict TLR-driven activation of NFκB. Failure to restrict NFκB resulted in the inflammation-induced DNA damage driven tyrosine phosphorylation of YAP, subsequent p53 accumulation and loss of intestinal epithelial homeostasis.

BackgroundPediatric osteomyelitis is a bacterial infection of bones requiring prolonged antibiotic treatment using parenteral followed by enteral agents. Major complications of pediatric osteomyelitis include transition to chronic osteomyelitis, formation of subperiosteal abscesses, extension of infection into the joint, and permanent bony deformity or limb shortening. Historically, osteomyelitis has been treated with long durations of antibiotics to avoid these complications. However, with improvements in management and antibiotic treatment, standard of care is moving towards short durations of intravenous antibiotics prior to enteral antibiotics.Methods/DesignThe authors will perform a systematic review based on PRISMA guidelines in order to evaluate the literature, looking for evidence to support the optimal duration of parenteral and enteral therapy. The main goals are to see if literature supports shorter durations of either parenteral antibiotics and/or enteral antibiotics.Multiple databases will be investigated using a thorough search strategy. Databases include Medline, Cochrane, EMBASE, SCOPUS, Dissertation Abstracts, CINAHL, Web of Science, African Index Medicus and LILACS. Search stream will include medical subject heading for pediatric patients with osteomyelitis and antibiotic therapy. We will search for published or unpublished randomized and quasi-randomized controlled trials.Two authors will independently select articles, extract data and assess risk of bias by standard Cochrane methodologies. We will analyze comparisons between dichotomous outcomes using risk ratios and continuous outcomes using mean differences. 95% confidence intervals will be computed.DiscussionOne of the major dilemmas of management of this disease is the duration of parenteral therapy. Long parenteral therapy has increased risk of serious complications and the necessity for long therapy has been called into question. Our study aims to review the currently available evidence from randomized trials regarding duration of both parenteral and oral therapy for pediatric acute osteomyelitis.Trial registrationCRD42013002320

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