Polygenic Overlap Between C-Reactive Protein, Plasma Lipids, and Alzheimer Disease
CIRCULATION
Authors: Desikan, Rahul S.; Schork, Andrew J.; Wang, Yunpeng; Thompson, Wesley K.; Dehghan, Abbas; Ridker, Paul M.; Chasman, Daniel I.; McEvoy, Linda K.; Holland, Dominic; Chen, Chi-Hua; Karow, David S.; Brewer, James B.; Hess, Christopher P.; Williams, Julie; Sims, Rebecca; O'Donovan, Michael C.; Choi, Seung Hoan; Bis, Joshua C.; Ikram, M. Arfan; Gudnason, Vilmundur; DeStefano, Anita L.; van der Lee, Sven J.; Psaty, Bruce M.; van Duijn, Cornelia M.; Launer, Lenore; Seshadri, Sudha; Pericak-Vance, Margaret A.; Mayeux, Richard; Haines, Jonathan L.; Farrer, Lindsay A.; Hardy, John; Ulstein, Ingun Dina; Aarsland, Dag; Fladby, Tormod; White, Linda R.; Sando, Sigrid B.; Rongve, Arvid; Witoelar, Aree; Djurovic, Srdjan; Hyman, Bradley T.; Snaedal, Jon; Steinberg, Stacy; Stefansson, Hreinn; Stefansson, Kari; Schellenberg, Gerard D.; Andreassen, Ole A.; Dale, Anders M.
Abstract
Background-Epidemiological findings suggest a relationship between Alzheimer disease (AD), inflammation, and dyslipidemia, although the nature of this relationship is not well understood. We investigated whether this phenotypic association arises from a shared genetic basis. Methods and Results-Using summary statistics (P values and odds ratios) from genome-wide association studies of >200 000 individuals, we investigated overlap in single-nucleotide polymorphisms associated with clinically diagnosed AD and C-reactive protein (CRP), triglycerides, and high-and low-density lipoprotein levels. We found up to 50-fold enrichment of AD single-nucleotide polymorphisms for different levels of association with C-reactive protein, low-density lipoprotein, high-density lipoprotein, and triglyceride single-nucleotide polymorphisms using a false discovery rate threshold <0.05. By conditioning on polymorphisms associated with the 4 phenotypes, we identified 55 loci associated with increased AD risk. We then conducted a meta-analysis of these 55 variants across 4 independent AD cohorts (total: n=29 054 AD cases and 114 824 healthy controls) and discovered 2 genome-wide significant variants on chromosome 4 (rs13113697; closest gene, HS3ST1; odds ratio=1.07; 95% confidence interval=1.05-1.11; P=2.86x10(-8)) and chromosome 10 (rs7920721; closest gene, ECHDC3; odds ratio=1.07; 95% confidence interval=1.04-1.11; P=3.38x10(-8)). We also found that gene expression of HS3ST1 and ECHDC3 was altered in AD brains compared with control brains. Conclusions-We demonstrate genetic overlap between AD, C-reactive protein, and plasma lipids. By conditioning on the genetic association with the cardiovascular phenotypes, we identify novel AD susceptibility loci, including 2 genome-wide significant variants conferring increased risk for AD.
Autoinflammation in addition to combined immunodeficiency: SLC29A3 gene defect
MOLECULAR IMMUNOLOGY
Authors: Cagdas, Deniz; Surucu, Naz; Tan, Cagman; Ozgul, Riza Koksal; Akkaya-Ulum, Yeliz Z.; Aydinoglu, Ayse Tulay; Aytac, Selin; Gumruk, Fatma; Balci-Hayta, Burcu; Balci-Peynircioglu, Banu; Ozen, Seza; Gursel, Mayda; Tezcan, Ilhan
Abstract
Introduction: H Syndrome is an autosomal recessive (AR) disease caused by defects in SLCA29A3 gene. This gene encodes the equilibrative nucleoside transporter, the protein which is highly expressed in spleen, lymph node and bone marrow. Autoinflammation and autoimmunity accompanies H Syndrome (HS). Aim: The aim was to further elucidate the mechanisms of disease by molecular studies in a patient with SLC29A3 gene defect. Patient and Methods: Mitochondrial dysfunction, lysosomal integrity, cytokine response in response to stimulation with different pattern recognition receptor ligands, and circulating cell-free mitochondrial-DNA(ccf-mtDNA) level in plasma were analyzed compared to controls to understand the cellular triggers of autoinflammation. RNA sequencing (RS) analyses were also performed in monocytes before/after culture with lipopolysaccharide. Results: Patient had progressive destructive arthropathy in addition to clinical findings due to combined immunodeficiency. Pure red cell aplasia (PRCA), vitiligo, diabetes, multiple autoantibody positivity, lymphopenia, increased acute phase reactants were present. Recent thymic emigrants (RTE), naive T cells were decreased, effector memory CD4 + T cells, nonclassical inflammatory monocytes were increased. Patient's peripheral blood mononuclear cells secreted more IL-1 beta and IL-6, showed lysosomal disruption and significant mitochondrial dysfunction compared to healthy controls. Plasma ccf-mtDNA level was significantly elevated compared to age-matched controls (p < 0.05). RNA sequencing studies revealed decreased expression of NLR Family Caspase Recrument-Domain Containing 4(NLRC4), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4(PFKFB4), serine dehydratase(SDS), heparan sulfate(Glucosamine) 3-O-sulfotransferase 1(HS3ST1), neutral cholesterol ester hydrolase 1 (NCEH1), and interleukin-8 (IL-8) in patient's monocytes compared to controls. Longstanding PRCA, which is possibly autoimmune, resolved after initiating monthly intravenous immunoglobulins (IVIG) and low dose steroids to the patient. Conclusion: Although autoinflammation and autoimmunity are reported in HS, by functional analyses we here show in the present patient that over-active inflammasome pathway in HS might be related with mitochondrial and lysosomal dysfunction. Increased plasma ccf-mtDNA may be used as a biomarker of inflammasomopathy in HS. HS should be included in the classification of primary immunodeficiency diseases.