Gene Expression Signature in Patients With Symptomatic Peripheral Artery Disease

Objective: Peripheral artery disease (PAD) is an atherothrombotic disease of the lower limbs with substantial morbidity and mortality. We used next-generation sequencing to identify genome-wide expression signatures associated with prevalent PAD and its outcomes. Approach and Results: We performed whole blood RNA sequencing among patients with severe symptomatic PAD undergoing lower extremity revascularization and controls. Dysregulated pathways and blood transcriptional modules were identified by comparing patients with PAD (n=42) to age- and sex-matched controls (N=29). The identified signature was compared in patients with PAD before LER with or without incident major adverse cardiac or limb events (MACLE). A novel microRNA associated with prevalent PAD and incident MACLE was then evaluated in a mouse hindlimb ischemia model. One hundred twenty-seven transcripts were differentially expressed (77 upregulated and 50 downregulated; adjusted P<0.05, |log2foldchange| >0.5) and analyzed using weighted gene co-expression network analysis. Weighted gene co-expression network analysis revealed blood modules enriched for immune activation, secretory granules, and coagulation in patients with PAD. Of these 127 differentially expressed transcripts, 40 were significantly associated with MACLE (log-rank false discovery rate <0.1). MicroRNA-4477b was significantly increased in patients with PAD with subsequent MACLE and in a mouse hindlimb ischemia model. Conclusions: A whole blood transcript signature identified patients with symptomatic PAD and PAD patients at increased risk of MACLE. A previously uncharacterized transcript microRNA-4477b was overexpressed in prevalent PAD, incident MACLE, and in a mouse hindlimb ischemia model. Our novel transcriptomic signature provides insight into potential mechanisms of patients with severe symptomatic PAD.

Automated summary

A transcriptomic signature identified patients with symptomatic PAD and those at increased risk of major adverse cardiac or limb events (MACLE). A specific microRNA, microRNA-4477b, was found to be overexpressed in prevalent PAD, incident MACLE, and in a mouse hindlimb ischemia model. This novel signature provides insights into potential mechanisms of severe symptomatic PAD.