Genetic Variation in MAP3K1 Associates with Ventilator-Free Days in Acute Respiratory Distress Syndrome.

Mitogen-activated protein kinase kinase kinase 1 (MAP3K1) regulates numerous intracellular signaling pathways involved in inflammation and apoptosis. We hypothesized that genetic variation in MAP3K1 might be associated with outcomes in patients with acute respiratory distress syndrome (ARDS), and that these variants would alter MAP3K1-mediated changes in inflammation and transcriptional regulation. To test this hypothesis, we genotyped single-nucleotide polymorphisms covering linkage disequilibrium bins in MAP3K1 in 306 subjects with ARDS from the ARDSNet FACTT (Fluid and Catheter Treatment Trial) study, and tested for associations between MAP3K1 single-nucleotide polymorphisms and ventilator-free days (VFDs) and mortality. We then validated these associations in a separate cohort of 241 patients with ARDS from Harborview Medical Center (Seattle, WA). We found the variant allele of rs832582 (MAP3K1906Val) was significantly associated with decreased VFDs using multivariate linear regression (-6.1 d, false discovery rate = 0.06) in the FACTT cohort. In the Harborview Medical Center cohort, subjects homozygous for MAP3K1906Val also had decreased VFDs (-15.1 d, false discovery rate < 0.01), and increased 28-day mortality (all subjects homozygous for the rare allele died). In whole blood stimulated with various innate immune agonists ex vivo, MAP3K1906Val was associated with increased IL-1ß, IL-6, IL-8, monocyte chemoattractant protein 1, and TNF-α production. Transcriptome analysis of whole blood stimulated with Toll-like receptor 4 agonist ex vivo demonstrated enrichment of inflammatory gene sets in subjects homozygous for MAP3K1906Val. Our findings show a robust association between the variant allele of rs832582 (MAP3K1906Val) and decreased VFDs in patients with ARDS and suggest that this variant may predispose individuals to a greater inflammatory response.

Toll-like receptor 1 polymorphisms and associated outcomes in sepsis after traumatic injury: a candidate gene association study.

OBJECTIVE: To determine whether single nucleotide polymorphisms (SNPs) in TLR1 are associated with mortality, specifically sepsis-associated mortality, in a traumatically injured population. BACKGROUND: Innate immune responses mediated by toll-like receptors (TLRs) induce early inflammatory responses to pathogen and damage-associated molecular patterns. Genetic variation in TLRs has been associated with susceptibility and outcomes in a number of infectious and noninfectious disease states. METHODS: Patients admitted to the trauma intensive care unit at a level 1 trauma center serving 4 states were enrolled and followed for development of infection, sepsis, and death. Genomic DNA was genotyped and logistic regression analysis was performed to determine associations between TLR1 SNPs and mortality. We further examined for associations between TLR1 SNPs and mortality in subgroups on the basis of the presence of sepsis and the type of sepsis-associated organism. RESULTS: We enrolled 1961 patients. TLR1-7202G (rs5743551) was associated with increased mortality after traumatic injury and this association was primarily observed in the subset of patients who developed sepsis [adjusted odds ratio (OR): 3.16; 95% confidence interval (CI): 1.43-6.97, P=0.004]. This association persisted after further restriction to gram-positive sepsis. TLR1(742A/G(Asn248Ser)) (rs4833095), a coding SNP in LD with TLR1-7202G, was also associated with mortality in gram-positive sepsis (adjusted OR: 4.16; 95% CI: 1.22-14.19, P=0.023). CONCLUSIONS: Genetic variation in TLR1 is associated with increased mortality in patients with sepsis after traumatic injury and may represent a novel marker of risk for death in critically injured patients.

Toll-like receptor 1 polymorphisms affect innate immune responses and outcomes in sepsis.

RATIONALE: Polymorphisms affecting Toll-like receptor (TLR)-mediated responses could predispose to excessive inflammation during an infection and contribute to an increased risk for poor outcomes in patients with sepsis. OBJECTIVES: To identify hypermorphic polymorphisms causing elevated TLR-mediated innate immune cytokine and chemokine responses and to test whether these polymorphisms are associated with increased susceptibility to death, organ dysfunction, and infections in patients with sepsis. METHODS: We screened single-nucleotide polymorphisms (SNPs) in 43 TLR-related genes to identify variants affecting TLR-mediated inflammatory responses in blood from healthy volunteers ex vivo. The SNP associated most strongly with hypermorphic responses was tested for associations with death, organ dysfunction, and type of infection in two studies: a nested case-control study in a cohort of intensive care unit patients with sepsis, and a case-control study using patients with sepsis, patients with sepsis-related acute lung injury, and healthy control subjects. MEASUREMENTS AND MAIN RESULTS: The SNP demonstrating the most hypermorphic effect was the G allele of TLR1(-7202A/G) (rs5743551), which associated with elevated TLR1-mediated cytokine production (P < 2 x 10(-20)). TLR1(-7202G) marked a coding SNP that causes higher TLR1-induced NF-kappaB activation and higher cell surface TLR1 expression. In the cohort of patients with sepsis TLR1(-7202G) predicted worse organ dysfunction and death (odds ratio, 1.82; 95% confidence interval, 1.07-3.09). In the case-control study TLR1(-7202G) was associated with sepsis-related acute lung injury (odds ratio, 3.40; 95% confidence interval, 1.59-7.27). TLR1(-7202G) also associated with a higher prevalence of gram-positive cultures in both clinical studies. CONCLUSIONS: Hypermorphic genetic variation in TLR1 is associated with increased susceptibility to organ dysfunction, death, and gram-positive infection in sepsis.

Inflammation and immune-related candidate gene associations with acute lung injury susceptibility and severity: a validation study.

INTRODUCTION: Common variants in genes related to inflammation, innate immunity, epithelial cell function, and angiogenesis have been reported to be associated with risks for Acute Lung Injury (ALI) and related outcomes. We tested whether previously-reported associations can be validated in an independent cohort at risk for ALI. METHODS: We identified 37 genetic variants in 27 genes previously associated with ALI and related outcomes. We prepared allelic discrimination assays for 12 SNPs from 11 genes with MAF>0.05 and genotyped these SNPs in Caucasian subjects from a cohort of critically ill patients meeting criteria for the systemic inflammatory response syndrome (SIRS) followed for development of ALI, duration of mechanical ventilation, and in-hospital death. We tested for associations using additive and recessive genetic models. RESULTS: Among Caucasian subjects with SIRS (n = 750), we identified a nominal association between rs2069832 in IL6 and ALI susceptibility (OR(adj) 1.61; 95% confidence interval [CI], 1.04-2.48, P = 0.03). In a sensitivity analysis limiting ALI cases to those who qualified for the Acute Respiratory Distress Syndrome (ARDS), rs61330082 in NAMPT was nominally associated with risk for ARDS. In terms of ALI outcomes, SNPs in MBL2 (rs1800450) and IL8 (rs4073) were nominally associated with fewer ventilator-free days (VFDs), and SNPs in NFE2L2 (rs6721961) and NAMPT (rs61330082) were nominally associated with 28-day mortality. The directions of effect for these nominal associations were in the same direction as previously reported but none of the associations survived correction for multiple hypothesis testing. CONCLUSION: Although our primary analyses failed to statistically validate prior associations, our results provide some support for associations between SNPs in IL6 and NAMPT and risk for development of lung injury and for SNPs in IL8, MBL2, NFE2L2 and NAMPT with severity in ALI outcomes. These associations provide further evidence that genetic factors in genes related to immunity and inflammation contribute to ALI pathogenesis.