The α2A-adrenergic receptor (ADRA2A) modulates susceptibility to Raynaud’s syndrome

Raynaud’s syndrome is a common dysautonomia where exposure to cold increases the vascular tone of distal arteries causing vasoconstriction and hypoxia, particularly in the extremities. Current treatment options are limited and unspecific. Biological mechanisms leading to the phenotype remain uncharacterized. Using genetic and electronic health record data from the UK Biobank, the Mass-General Brigham Biobank, the Estonian Biobank, and the FinnGen study, we identified 11,358 individuals with a diagnosis of Raynaud’s syndrome and 1,106,871 population controls. We found eight loci including endothelial nitric oxide synthase ( NOS3 ), HLA, and a notable association at the α2A-adrenergic receptor ( ADRA2A) locus (rs7090046, P = 3.93×10-47), implicating adrenergic signaling as a major risk factor with Raynaud’s syndrome. We further investigate the role of the variants and ADRA2A expression in functional and physiological models. In silico follow-up analysis revealed an expression quantitative trait locus (eQTL) that co-localized and increased ADRA2A gene expression in a tissue-specific manner in the distal arteries. Staining with RNA scope further clarified the specificity of ADRA2A expression in small vessels. We show by CRISPR gene editing that the SNP region modifies ADRA2A gene expression in pulmonary artery smooth muscle cells. Finally, we performed a functional contraction assay on smooth muscle cells in cold conditions and showed lower contraction in ADRA2A -deficient and higher contraction in ADRA2A -overexpressing smooth muscle cells. Our results indicate that Raynaud’s syndrome is related to vascular function mediated by adrenergic signaling through ADRA2A . Our study highlights the power of genome-wide association testing as a discovery tool for poorly understood clinical endpoints and further clarifies the role of adrenergic signaling in Raynaud’s syndrome by fine-mapping, using in vitro genomic manipulations and functional validation in distal smooth muscle cell populations located in arterioles ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was funded by the Instrumentarium Science Foundation (230041), the Academy of Finland (340539), Doctoral Programme Brain and Mind (University of Helsinki). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of the Institute for Molecular Medicine Finland gave ethical approval for this work. Ethics committee/IRB of the FinnGen study gave ethical approval for this work. Ethics committee/IRB of Stanford University gave ethical approval for this work. Ethics committee/IRB of the Estonian Biobank gave ethical approval for this work. Ethics committee/IRB of the Mass-General Brigham Biobank gave ethical approval for this work. Ethics committee/IRB of the UK Biobank gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Individual-level data for can be accessed on successful application for cohorts used in this study. The FinnGen individual-level data may be accessed through applications to the Finnish Biobanks' FinnBB portal, Fingenious ([www.finbb.fi][1]). For the individual-level data of the UKB, applications can be made through the UKB portal at . For MGB, individual-level data are available from the Mass General Brigham Human Research Office/Institutional Review Board at Mass General Brigham (contact located at ) for researchers who meet the criteria for access to confidential data. Lastly, for the EstBB, preliminary inquiries to access individual-level data for scientific research can be sent to releases{at}ut.ee. Summary-level data is available upon reasonable request. [1]: http://www.finbb.fi