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Nonsteroidal anti-inflammatory drugs alter the spatiotemporal organization of Ras proteins on the plasma membrane.

ABSTRACT: Ras proteins on the inner leaflet of the plasma membrane signal from transient nanoscale proteolipid assemblies called nanoclusters. Interactions between the Ras lipid anchors and plasma membrane phospholipids, cholesterol, and actin cytoskeleton contribute to the formation, stability, and dynamics of Ras nanoclusters. Many small biological molecules are amphiphilic and capable of intercalating into membranes and altering lipid immiscibility. In this study we systematically examined whether amphiphiles such as indomethacin influence Ras protein nanoclustering in intact plasma membrane. We found that indomethacin, a nonsteroidal anti-inflammatory drug, induced profound and complex effects on Ras spatial organization, all likely related to liquid-ordered domain stabilization. Indomethacin enhanced the clustering of H-Ras.GDP and N-Ras.GTP in cholesterol-dependent nanoclusters. Indomethacin also abrogated efficient GTP-dependent lateral segregation of H- and N-Ras between cholesterol-dependent and cholesterol-independent clusters, resulting in mixed heterotypic clusters of Ras proteins that normally are separated spatially. These heterotypic Ras nanoclusters showed impaired Raf recruitment and kinase activation resulting in significantly compromised MAPK signaling. All of the amphiphilic anti-inflammatory agents we tested had similar effects on Ras nanoclustering and signaling. The potency of these effects correlated with the membrane partition coefficients of the individual agents and was independent of COX inhibition. This study shows that biological amphiphiles have wide-ranging effects on plasma membrane heterogeneity and protein nanoclustering, revealing a novel mechanism of drug action that has important consequences for cell signaling.

SUBMITTER: Zhou Y

PROVIDER: S-EPMC3351306 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature

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Nonsteroidal anti-inflammatory drugs alter the spatiotemporal organization of Ras proteins on the plasma membrane.

Zhou Yong Y Cho Kwang-Jin KJ Plowman Sarah J SJ Hancock John F JF

The Journal of biological chemistry 20120319 20

Ras proteins on the inner leaflet of the plasma membrane signal from transient nanoscale proteolipid assemblies called nanoclusters. Interactions between the Ras lipid anchors and plasma membrane phospholipids, cholesterol, and actin cytoskeleton contribute to the formation, stability, and dynamics of Ras nanoclusters. Many small biological molecules are amphiphilic and capable of intercalating into membranes and altering lipid immiscibility. In this study we systematically examined whether amph ...[more]

PMID: 22433858

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Project description:Clostridium difficile infection (CDI) is a major public health threat worldwide. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with enhanced susceptibility to and severity of CDI; however, the mechanisms driving this phenomenon have not been elucidated. NSAIDs alter prostaglandin (PG) metabolism by inhibiting cyclooxygenase (COX) enzymes. Here, we found that treatment with the NSAID indomethacin prior to infection altered the microbiota and dramatically increased mortality and the intestinal pathology associated with CDI in mice. We demonstrated that in C. difficile-infected animals, indomethacin treatment led to PG deregulation, an altered proinflammatory transcriptional and protein profile, and perturbed epithelial cell junctions. These effects were paralleled by increased recruitment of intestinal neutrophils and CD4+ cells and also by a perturbation of the gut microbiota. Together, these data implicate NSAIDs in the disruption of protective COX-mediated PG production during CDI, resulting in altered epithelial integrity and associated immune responses.IMPORTANCE Clostridium difficile infection (CDI) is a spore-forming anaerobic bacterium and leading cause of antibiotic-associated colitis. Epidemiological data suggest that use of nonsteroidal anti-inflammatory drugs (NSAIDs) increases the risk for CDI in humans, a potentially important observation given the widespread use of NSAIDs. Prior studies in rodent models of CDI found that NSAID exposure following infection increases the severity of CDI, but mechanisms to explain this are lacking. Here we present new data from a mouse model of antibiotic-associated CDI suggesting that brief NSAID exposure prior to CDI increases the severity of the infectious colitis. These data shed new light on potential mechanisms linking NSAID use to worsened CDI, including drug-induced disturbances to the gut microbiome and colonic epithelial integrity. Studies were limited to a single NSAID (indomethacin), so future studies are needed to assess the generalizability of our findings and to establish a direct link to the human condition.

Project description:Background & aimsNonsteroidal anti-inflammatory drugs (NSAIDs) have been suggested to protect against esophageal adenocarcinoma (EAC). This study examined the effect of NSAIDs on the risk of developing Barrett's esophagus (BE), the precursor lesion to EAC.MethodsWe conducted a case-control study among eligible patients scheduled for either elective esophagogastroduodenoscopy (EGD) or recruited from primary care clinics to undergo a study EGD. We compared 323 patients with BE (296 nondysplastic and 27 dysplastic) with 2 separate control groups: 1347 patients from the elective EGD group (endoscopy controls) and 502 patients from the primary care group (primary care controls) with no endoscopic or histopathologic BE. Use of aspirin products and 23 nonaspirin NSAIDs was ascertained from detailed, self-reported questionnaires. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariable logistic regression models.ResultsThere were no significant differences in self-reported NSAID use between all BE cases and all controls (58.2% vs 54.6%; P = .33); this was seen for aspirin products (43.0% vs 37.4%; P = .08) and nonaspirin NSAIDs (7.7% vs 8.9%; P = .46). These findings persisted in the multivariable model for any NSAIDs (adjusted OR, 0.89; 95% CI, 0.75-1.28), aspirin (adjusted OR, 1.16; 95% CI, 0.90-1.51), and nonaspirin NSAIDs (adjusted OR, 0.88; 95% CI, 0.55-1.39). Use of a combination of aspirin and nonaspirin NSAIDs was reported in 7.4% of cases and 8.3% of controls, and a nonsignificant inverse association with BE was seen (adjusted OR, 0.70; 95% CI, 0.44-1.11). There was no significant association between BE and daily NSAID use (adjusted OR, 1.03; 95% CI, 0.78-1.37). Similar findings were observed for comparisons involving nondysplastic or dysplastic BE cases, and endoscopy or primary care control groups separately or combined.ConclusionsThe use of NSAIDs was not associated with a reduced risk of BE. It is likely that the protective mechanism of NSAIDs on EAC occurs subsequent to the development of BE.

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Nonsteroidal anti-inflammatory drugs alter the spatiotemporal organization of Ras proteins on the plasma membrane.

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Nonsteroidal anti-inflammatory drugs alter the spatiotemporal organization of Ras proteins on the plasma membrane.

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