A Missense Variant in the IL-6 Receptor and Protection From Peripheral Artery Disease

HomeCirculation ResearchVol. 129, No. 10A Missense Variant in the IL-6 Receptor and Protection From Peripheral Artery Disease Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessLetterPDF/EPUBA Missense Variant in the IL-6 Receptor and Protection From Peripheral Artery Disease Michael G. Levin, Derek Klarin, Marios K. Georgakis, Julie Lynch, Katherine P. Liao, Benjamin F. Voight, Christopher J. O'Donnell, Kyong-Mi Chang, Themistocles L. Assimes, Philip S. Tsao, Scott M. Damrauer and on behalf of the VA Million Veteran Program Michael G. LevinMichael G. Levin https://orcid.org/0000-0002-9937-9932 Cardiovascular Medicine (M.G.L.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Department of Medicine (M.G.L., K.-M.C.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA (M.G.L., K.-M.C., S.M.D.). , Derek KlarinDerek Klarin https://orcid.org/0000-0002-4636-5780 Malcolm Randall VA Medical Center, Gainesville, FL (D.K.). Department of Surgery, University of Florida, Gainesville (D.K.). , Marios K. GeorgakisMarios K. Georgakis https://orcid.org/0000-0003-3507-3659 Institute for Stroke and Dementia Research, University Hospital, Ludwig-Maximilians-University LMU, Munich, Germany (M.K.G.). Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA (M.K.G.). Program in Medical and Population Genetics, Broad Institute of Harvard and the Massachusetts Institute of Technology, Cambridge, MA (M.K.G.). , Julie LynchJulie Lynch Edith Nourse VA Medical Center, Bedford, MA (J.L.). VA Informatics and Computing Infrastructure, Salt Lake City, UT (J.L.). , Katherine P. LiaoKatherine P. Liao https://orcid.org/0000-0002-4797-3200 VA Boston Healthcare System, Boston, MA (K.P.L., C.J.O.). Harvard Medical School, Boston, MA (K.P.L., C.J.O.). Brigham and Women's Hospital, Boston, MA (K.P.L., C.J.O.). , Benjamin F. VoightBenjamin F. Voight Genetics (B.F.V.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Institute for Translational Medicine and Therapeutics (B.F.V.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA (B.F.V.). , Christopher J. O'DonnellChristopher J. O'Donnell https://orcid.org/0000-0002-2667-8624 VA Boston Healthcare System, Boston, MA (K.P.L., C.J.O.). Harvard Medical School, Boston, MA (K.P.L., C.J.O.). Brigham and Women's Hospital, Boston, MA (K.P.L., C.J.O.). , Kyong-Mi ChangKyong-Mi Chang Department of Medicine (M.G.L., K.-M.C.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA (M.G.L., K.-M.C., S.M.D.). , Themistocles L. AssimesThemistocles L. Assimes https://orcid.org/0000-0003-2349-0009 Palo Alto VA Healthcare System, CA (T.L.A., P.S.T.). Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA; (T.L.A., P.S.T.). Stanford Cardiovascular Institute, Stanford University, Stanford, CA (T.L.A., P.S.T.). , Philip S. TsaoPhilip S. Tsao https://orcid.org/0000-0001-7274-9318 Palo Alto VA Healthcare System, CA (T.L.A., P.S.T.). Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA; (T.L.A., P.S.T.). Stanford Cardiovascular Institute, Stanford University, Stanford, CA (T.L.A., P.S.T.). , Scott M. DamrauerScott M. Damrauer Correspondence to: Scott M. Damrauer, MD, University of Pennsylvania Perelman School of Medicine, 3900 Woodland Ave, Philadelphia, PA 19104. Email E-mail Address: [email protected] https://orcid.org/0000-0001-8009-1632 Surgery (S.M.D.), University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA (M.G.L., K.-M.C., S.M.D.). and on behalf of the VA Million Veteran Program Originally published22 Sep 2021https://doi.org/10.1161/CIRCRESAHA.121.319589Circulation Research. 2021;129:968–970is related toMeet the First AuthorsMeet the First Author, see p 894IL (interleukin)-6 represents a key effector of immune activation and systemic inflammation, which have been linked to adverse cardiovascular outcomes. Observational genetic studies have linked a common (minor allele frequency, 0.33) missense variant (rs2228145; p.Asp358Ala) in IL6R (IL-6 receptor) with reduced risk of coronary artery disease (CAD), abdominal aortic aneurysm, ischemic stroke, and peripheral artery disease (PAD).1,2 This common variant impairs classical IL-6 signaling by reducing membrane-bound IL6R, increasing circulating levels of IL6R (+34.3% per minor allele), and dampening the inflammatory response.1,3 The effects of this variant on trans-signaling are less certain.3 Mendelian randomization (MR) analyses have similarly highlighted IL6 as a potential therapeutic target, providing a causal link between genetic downregulation of IL-6 and decreased risk of CAD, stroke, and abdominal aortic aneurysm.4 Although PAD represents a common form of atherosclerotic cardiovascular disease associated with substantial morbidity and mortality, whether systemic downregulation of IL-6–mediated inflammation represents a causal therapeutic target for PAD remains unknown. To investigate, we performed 3 complementary analyses utilizing data from the VA Million Veteran Program (MVP).First, we studied 35 042 PAD cases and 247 115 controls with available rs2228145 (IL6R Asp358Ala) genotype and electronic health record data, with phenotyping, genotyping, and quality control performed as described previously, using diagnosis codes extracted from the VA electronic health record.5 Logistic regression (unless otherwise specified) was performed within each genetically determined ancestral population, adjusted for age, sex, 5 genetic principal components, and genotyping batch, and combined using fixed-effects meta-analysis to test the association between rs2228145 genotype and each PAD-related outcome. For comparison, we studied 77 241 CAD cases and 139 284 controls.Among the overall cohort, IL6R Asp358Ala was associated with decreased risk of PAD, without evidence of significant heterogeneity across ancestries (I2, 0.21; Cochran Q P=0.28; Figure [A]). Results were similar when meta-analyzed with PAD GWAS from BioBank Japan and FinnGen and in models adjusted for each traditional risk factor (hypertension, diabetes, smoking, and LDL [low-density lipoprotein] cholesterol) among MVP participants. No interactions between IL6R Asp358Ala and each risk factor or statin use were detected. Results were also similar for CAD (Figure [A]) and in multinomial logistic regression examining increasingly severe manifestations of PAD in MVP (Figure [B]).Download figureDownload PowerPointFigure. Results of genetic analyses investigating the relationship between IL6R and PAD. Associations between IL6R (IL-6 receptor) Asp358Ala and (A) peripheral artery disease (PAD; Million Veteran Program [MVP]: 35 042 cases [27 013 European, 5939 African, and 2090 Hispanic] and 247 115 controls [176 750 European, 49 403 African, and 20 962 Hispanic]; and fixed-effects meta-analysis of MVP, BioBank Japan [BBJ], and FinnGen release 5 [FNG]) and coronary artery disease (CAD; MVP: 77 241 CAD cases [62 060 European, 10 775 African, and 4406 Hispanic] and 139 284 controls [97 640 European, 28 265 African, and 13 379 Hispanic]), and (B) increasingly severe manifestations of PAD (claudication; chronic limb threatening ischemia [CLTI]: rest pain, gangrene, ulcer; and amputation) among MVP participants. C, Plot comparing the P for genetic variants associated with soluble IL6R (sIL6R; IMPROVE) and PAD (MVP) at the ±1-Mb region surrounding the lead sIL6R protein quantitative trait locus (pQTL; rs4129267; located on chromosome 1, identifying rs7521458 as the variant with the lowest combined P as determined by LocusCompare (https://github.com/boxiangliu/locuscompare) and (D) regional association plots for IL6R (IMPROVE) and PAD (MVP) at this locus, with colocalization identifying a high probability of a single shared causal genetic association. E, MR results for effect of sIL6R (IMPROVE) on PAD (MVP). As genetic instruments, we utilized 15 independent (r2<0.1) SNPs associated with log-transformed sIL6R at genome-wide significance (P<5×10−8) in the IMPROVE study. Mean F statistic was 174.5 (range, 31.6–1456.9). Unadjusted P values are presented for all analyses. OR indicates odds ratio.Next, we tested for the presence of a shared genetic signal influencing circulating soluble IL-6R (sIL6R) and PAD using colocalization (https://chr1swallace.github.io/coloc/). A protein quantitative trait locus associated with sIL6R was previously identified among up to 3394 participants of the IMPROVE study (https://doi.org/10.5281/zenodo.264128). We identified strong evidence for a single shared causal genetic signal for sIL6R and PAD (posterior probability, 0.93) for the region ±1 Mb surrounding the lead sIL6R protein quantitative trait locus variant (rs4129267; Figure [C and D]).Finally, we performed 2-sample MR to further assess the causal role between IL-6 signaling and PAD. The hypothesized mechanism for CAD risk reduction is shedding of the IL6R from the cell surface into circulation, leading to decreased classical IL6 signaling.1,3 Higher circulating levels of sIL6R would, therefore, be expected to decrease classical IL6 signaling, leading to reduced risk of PAD.Indeed, in inverse-variance weighted MR, increased levels of sIL6R were associated with significantly decreased risk of PAD (Figure [E]). We did not detect evidence of directional pleiotropy (Egger intercept, P>0.05) or significant heterogeneity (Cochran Q, P>0.05). Results were consistent across MR methods that make different assumptions about the presence of pleiotropy (weighted median and MR-PRESSO [Mendelian Randomization Pleiotropy RESidual Sum and Outlier]).Overall, these results implicate IL-6 signaling in the pathogenesis of PAD, across a combination of observational and causal genetic analyses. These results are consistent with a prior phenome-wide association study of rs2228145 in MVP.2 We extend these findings to (1) link IL-6 signaling to PAD, PAD subtypes, and risk of amputation and (2) prioritize IL6R as a causal therapeutic target to reduce risk of PAD. Consistent findings across both PAD and CAD represent evidence for a role of inflammation in systemic atherosclerosis. Future study is necessary to determine whether rs2228145 may be associated with decreased CAD burden/severity (considering our finding of reduced risk of severe PAD/amputation). This large, multiancestry study in the MVP population had a high prevalence of PAD (12.5%), in contrast to a prior study of European UK Biobank participants, which failed to detect an association between IL-6 signaling and PAD.4 Limitations include the high proportion of men among MVP participants (>90%). Recent randomized trials focused on CAD outcomes have demonstrated beneficial effects of targeting systemic inflammation with canakinumab and colchicine, and monoclonal antibodies targeting IL-6 signaling (tocilizumab, sarilumab, and siltuximab) are clinically approved for other indications. Phenome-wide association and MR studies demonstrate a similar safety profile for genetically proxied decreases in classical IL6 signaling and therapeutic modulation of IL6/IL6R.2,4 Trials targeting systemic inflammation may be warranted to characterize the net benefits in the prevention of PAD specifically.Data AvailabilityThe data that support the findings of this study are available from the corresponding author upon reasonable request.Article InformationSources of FundingThis study is funded by the National Institutes of Health and the US Department of Veterans Affairs.DisclosuresDr. Damrauer receives research support to his institution from RenalytixAI and reports consulting fees from Calico Labs, all outside the current work.FootnotesFor Sources of Funding and Disclosures, see page 970.Correspondence to: Scott M. Damrauer, MD, University of Pennsylvania Perelman School of Medicine, 3900 Woodland Ave, Philadelphia, PA 19104. Email [email protected]eduReferences1. Libby P. Targeting inflammatory pathways in cardiovascular disease: the inflammasome, interleukin-1, interleukin-6 and beyond.Cells. 2021; 10:951. doi: 10.3390/cells10040951CrossrefMedlineGoogle Scholar2. Cai T, Zhang Y, Ho YL, Link N, Sun J, Huang J, Cai TA, Damrauer S, Ahuja Y, Honerlaw J, et al.; VA Million Veteran Program. Association of interleukin 6 receptor variant with cardiovascular disease effects of interleukin 6 receptor blocking therapy: a phenome-wide association study.JAMA Cardiol. 2018; 3:849–857. doi: 10.1001/jamacardio.2018.2287CrossrefMedlineGoogle Scholar3. Ferreira RC, Freitag DF, Cutler AJ, Howson JM, Rainbow DB, Smyth DJ, Kaptoge S, Clarke P, Boreham C, Coulson RM, et al.. Functional IL6R 358Ala allele impairs classical IL-6 receptor signaling and influences risk of diverse inflammatory diseases.PLoS Genet. 2013; 9:e1003444. doi: 10.1371/journal.pgen.1003444CrossrefMedlineGoogle Scholar4. Georgakis MK, Malik R, Li X, Gill D, Levin MG, Vy HMT, Judy R, Ritchie M, Verma SS, Nadkarni GN, et al.; Regeneron Genetics Center. Genetically downregulated Interleukin-6 Signaling is associated with a favorable cardiometabolic profile: a phenome-wide association study.Circulation. 2021; 143:1177–1180. doi: 10.1161/CIRCULATIONAHA.120.052604LinkGoogle Scholar5. Klarin D, Lynch J, Aragam K, Chaffin M, Assimes TL, Huang J, Lee KM, Shao Q, Huffman JE, Natarajan P, et al.; VA Million Veteran Program. Genome-wide association study of peripheral artery disease in the Million Veteran Program.Nat Med. 2019; 25:1274–1279. doi: 10.1038/s41591-019-0492-5CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsRelated articlesMeet the First AuthorsCirculation Research. 2021;129:892-894 October 29, 2021Vol 129, Issue 10Article InformationMetrics Download: 297 © 2021 American Heart Association, Inc.https://doi.org/10.1161/CIRCRESAHA.121.319589PMID: 34547901 Originally publishedSeptember 22, 2021 Keywordsmutationperipheral artery diseasecoronary Artery diseasegeneticsinflammationinterleukin-6cardiovascular diseasesPDF download SubjectsAtherosclerosisCoronary Artery DiseaseGeneticsPeripheral Vascular Disease