Markus Ramste

Raynaud's syndrome is a dysautonomia where exposure to cold causes vasoconstriction and hypoxia, particularly in the extremities. We performed meta-analysis in four cohorts and discovered eight loci (ADRA2A, IRX1, NOS3, ACVR2A, TMEM51, PCDH10-DT, HLA, and RAB6C) where ADRA2A, ACVR2A, NOS3, TMEM51, and IRX1 co-localized with expression quantitative trait loci (eQTLs), particularly in distal arteries. CRISPR gene editing further showed that ADRA2A and NOS3 loci modified gene expression and in situ RNAscope clarified the specificity of ADRA2A in small vessels and IRX1 around small capillaries in the skin. A functional contraction assay in the cold showed lower contraction in ADRA2A-deficient and higher contraction in ADRA2A-overexpressing smooth muscle cells. Overall, our study highlights the power of genome-wide association testing with functional follow-up as a method to understand complex diseases. The results indicate temperature-dependent adrenergic signaling through ADRA2A, effects at the microvasculature by IRX1, endothelial signaling by NOS3, and immune mechanisms by the HLA locus in Raynaud's syndrome.

Abstract Objective Acute coronary syndrome (ACS) incidence and case fatality (CF) have declined in the past decades, but some studies have suggested a potential stagnation in this decline. We examined how the ACS burden has evolved among persons aged 35-74 in Finland from 1996 to 2021. Methods We used Finnish country-wide Hospital Discharge- and Causes of Death-Registers covering first non-fatal and fatal ACS events, totaling 69 906 442 person-years at risk. We analyzed incidence, mortality, and 28-day CF, and their trends using negative binomial, Poisson, segmented, and logistic regression adjusting for age and sex. Results Altogether, the analysis consisted of 186 489 non-fatal and 72 907 fatal ACS events. ACS incidence declined in men (annual percentage change (APC) −2.0% [95% CI −2.2 to −1.8]) and in older women (APC of 55-64 year old −1.5% [−1.7 to −1.2] and 65-74 year old −3.3% [−3.4 to −3.2]), but the incidence decline slowed down over the last decade. In younger women aged 35-54, incidence was unchanged during the study period. ACS mortality and CF declined (APC of the mortality in men - 4.4% [−4.6 to −4.2] and in women −5.0% [−5.2 to −4.7]. APC of CF in men −2.7% [−2.8 to −2.6] and in women −3.3% [−3.6 to −3.1]). Conclusions ACS mortality declined in all groups, but the decline in ACS incidence slowed down and even halted in women. In women aged 35-54, the incidence was unchanged during the study period. These results emphasize the need of intensified cardiovascular prevention, particularly in women. Key messages What is already known on this topic During the last decades coronary artery disease treatment and prevention have improved worldwide which has led to a decline in ACS mortality and case fatality. However, recent studies from several countries suggest, that incidence decline has stagnated or even turned to increase, especially in younger age cohorts. What this study adds This study showed that incidence has ceased its decline in women aged 35-54 and has slowed down in older age groups. Together with declining mortality this results in a growing number of patients living with cardiovascular disease leading to increased healthcare costs . How this study might affect research, practice, or policy The alarming results of this study underline the importance of intensifying prevention, focusing especially on young and middle-aged women .

Thank you to Dr. Flavahan and Dr. Eid for their thoughtful responses to our recent paper, “Genetic and functional analysis of Raynaud’s syndrome implicates loci in vasculature and immunity,” published in Cell Genomics. We appreciate the opportunity to engage in scientific discourse and discuss the methodology and conclusions presented in our study.

The majority of variants identified by genome-wide association studies (GWAS) that influence coronary artery disease (CAD) risk reside in noncoding regions of the genome, making it challenging to link them with the genes they regulate. The 9p21.3 locus is the most impactful genetic risk locus for CAD. Due to the complexity of this locus, the causal genes and molecular mechanisms are poorly understood. Enhancers are cell type specific, and vascular smooth muscle cells (SMC) are known to have the highest heritable risk for CAD and play a major role in the atherosclerotic plaque formation. Here, we report efforts to systematically map SMC specific enhancers to neighboring genes within the 9p21.3 locus by implementing single cell CRISPRi enhancer screens and validating single causal variants in these enhancers. First, we intersected CAD GWAS loci with human coronary artery SMC (HCASMC) ATAC-seq and H3K27ac ChIP-seq datasets to focus on the disease relevant SNPs. This analysis identified 27 SNPs in 11 enhancers, that we targeted with CRISPRi machinery and analyzed at 5- and 10-days post transduction. As target genes in the locus are lowly expressed, we employed the targeted Perturb-seq (TAP-seq) approach for library generation and sequencing. We identified several enhancer-gene -pairs, including a strong enhancer-gene connection to both CDKN2A and CDKN2B . Additionally, we identified multiple enhancer regions that control MTAP expression, with smaller but significant effects. We followed up with individual validation of enhancer-gene pairs through qPCR. Furthermore, these results are consistent with chromosomal interaction data obtained from our previous HiChIP. Notably, enhancers 5 and 6 were strong regulators of CDNK2B and CDKN2A expression, so we investigated how variants in these enhancers might directly disrupt transcription factor (TF) binding. By using luciferase enhancer assays, CHIPseq and phenotypic in vitro assays we linked this variation with TFs that drive vascular calcification in SMCs. Our results identify new variant to gene links and suggest how the genetic risk in 9p21 is mediated in the vascular wall, providing mechanistic understanding of vascular calcification and genetic risk of CAD and suggesting a novel mechanism of how 9p21.3 mediates disease risk.

Abstract Background Narcolepsy is a debilitating sleep disorder caused by hypocretin deficiency. Aside from its role to induce wakefulness, hypocretin is linked to modulated appetite and metabolism, often resulting in weight gain. Study objectives We aimed to unravel the comprehensive epidemiological connection between narcolepsy and major cardiometabolic outcomes. Methods We analyzed cardiovascular and metabolic disease distribution in the FinnGen study. Using longitudinal electronic health records, we assessed associations between narcolepsy, cardiac/metabolic markers, and prescriptions for relevant drugs. Results Our findings demonstrate significant associations between narcolepsy and metabolic traits (OR [95% CI] = 2.65 [1.81, 3.89]) as well as stroke (OR = 2.36 [1.38, 4.04]). Narcolepsy patients exhibit a less favourable metabolic profile, including higher glucose levels (OR = 1.1143 [1.0599, 1.1715]) and dyslipidaemia. This is supported by increased prescriptions of insulin (OR = 2.269 [1.46, 3.53]), simvastatin (OR = 2.292 [1.59, 3.31]), and metformin (OR = 2.327 [1.66, 3.25]), reflecting high metabolic disturbances. Furthermore, positive associations with antihypertensive and antiplatelet medications were observed, consistent with elevated cardiovascular risk. Conclusion Taken together, our findings highlight the cardiometabolic burden in narcolepsy. This study enhances understanding of the metabolic and cardiovascular consequences of narcolepsy and offers timely guidance for effective disease control. Abstract Figure