D, presumably due to a process that is dependent on actin remodeling, as both Lat B and jasplakinolide treatment of L6 cells blocked efficient disassembly of the IRS1/nexilin complex in response to insulin. We show that insulin-elicited release of the 22948146 inhibitory constraint exerted by nexilin enhances the efficiency of IRS1/PI3K interaction and PI-3, 4, 5-P3 production at localized sites which in turn impacts the sensitivity and magnitude of Akt activation. Given the localization of nexilin to the sarcomeric Zdisc, it would be of interest to assess whether it regulates contraction-stimulated glucose uptake in adult skeletal muscle. This study also opens doors to explore what role if any nexilin may play in the development of skeletal muscle insulin resistance. Moreover, it raises the possibility that loss of function mutations in the CC domain of nexilin that have been identified in patients with hypertrophic cardiomyopathy may be coupled to derangements in the IRS1/Akt signaling pathway.Nexilin Binds and Regulates IRSFigure 8. Overexpression of nexilin suppresses IRS1/PI3K signaling in 3T3-L1 adipocytes. A) 3T3-L1 adipocytes transduced with adenoviruses expressing FLAG-nexilin (ad-Nex) or GFP (Ad-GFP) were serum starved 72hrs post-infection and either left untreated or stimulated with increasing concentration of insulin. Cell lysates were subjected to Western blot analysis using the indicated antibodies. B) 3T3-L1 adipocytes transduced as in A) were starved or stimulated with 10 nM insulin and exposed to [3H] 2-deoxyglucose for 5 minutes. The reaction was ceased and the cells were harvested to assess the presence of [3H] within the cell through liquid scintillation 22948146 inhibitory constraint exerted by nexilin enhances the efficiency of IRS1/PI3K interaction and PI-3, 4, 5-P3 production at localized sites which in turn impacts the sensitivity and magnitude of Akt activation. Given the localization of nexilin to the sarcomeric Zdisc, it would be of interest to assess whether it regulates contraction-stimulated glucose uptake in adult skeletal muscle. This study also opens doors to explore what role if any nexilin may play in the development of skeletal muscle insulin resistance. Moreover, it raises the possibility that loss of function mutations in the CC domain of nexilin that have been identified in patients with hypertrophic cardiomyopathy may be coupled to derangements in the IRS1/Akt signaling pathway.Nexilin Binds and Regulates IRSFigure 8. Overexpression of nexilin suppresses IRS1/PI3K signaling in 3T3-L1 adipocytes. A) 3T3-L1 adipocytes transduced with adenoviruses expressing FLAG-nexilin (ad-Nex) or GFP (Ad-GFP) were serum starved 72hrs post-infection and either left untreated or stimulated with increasing concentration of insulin. Cell lysates were subjected to Western blot analysis using the indicated antibodies. B) 3T3-L1 adipocytes transduced as in A) were starved or stimulated with 10 nM insulin and exposed to [3H] 2-deoxyglucose for 5 minutes. The reaction was ceased and the cells were harvested to assess the presence of [3H] within the cell through liquid scintillation 11967625 counting. Data are means 6 SE, n = 3 per group, oneway ANOVA (* P,0.001). doi:10.1371/journal.pone.0055634.gAuthor ContributionsConceived and designed the experiments: JEP MRA. Performed the experiments: AL FH . Analyzed the data: AL FH PN JEP MRA.Contributed reagents/materials/analysis tools: PN. Wrote the paper: AL JEP MRA.
Cardiovascular diseases are the leading cause of death in the developed countries, and one of the main risk factors for cardiovascular mortality is obesity. The incidence of obesity is increasing at a rapid rate, particularly in children and adolescents [1]. Moreover, being overweight at a young age predisposes to adult obesity [2]and induces irreversible changes in the cardiovascular system leading to impairment of cardiac and coronary function in the adult [3] increasing the risk of suffering coronary disease [4,5]later in life. Likewise, in experimental animals perinatal overnutrition induced by either maternal obesity [6] or by postnatal overfeeding [7] has been reported to induce longterm effects in metabolism and cardiovascular function [8] possible due to changes in postnatal leptin levels [9]. Recent studies suggest that angiotensin II may be one of the factors promoting cardiovascular disease in the obese. Angiotensin II is produced by enzymatic cleavage of the precursor angiotensinogen by renin and by angiotensin-converting enzyme (ACE), and exerts its effects in the tissues through angiotensin receptors type1 (AGTRa) and type 2 (AGTR2). These components of the renin-angiotensin system are present in visceral and subcutaneous adipose tissue [10], and are increased in obesity [11]. There is a positive correlation between obesity and angiotensinogen expression in adipose tissue both in humans [12,13] and in rats [14,15]. In addition renin (REN), A.