EX VIVO IKKbeta ABLATION RESCUES THE IMMUNOPOTENCY OF MESENCHYMAL STROMAL CELLS FROM DIABETICS WITH ADVANCED ATHEROSCLEROSIS.

AIM: Diabetes is a conventional risk factor for atherosclerotic cardiovascular disease and myocardial infarction (MI) is the most common cause of death among these patients. Mesenchymal stromal cells (MSCs) in patients with type 2 diabetes (T2DM) and atherosclerosis have impaired ability to suppress activated T-cells (i.e. reduced immunopotency). This is mediated by an inflammatory shift in MSC secreted soluble factors (i.e. pro-inflammatory secretome) and can contribute to the reduced therapeutic effects of autologous T2DM and atherosclerosis-MSC post-myocardial infarction. The signaling pathways driving the altered secretome of atherosclerosis- and T2DM-MSC are unknown. Specifically, the effect of IkappaB kinase beta (IKKbeta) modulation, a key regulator of inflammatory responses, on the immunopotency of MSCs from T2DM patients with advanced atherosclerosis has not been studied. METHODS AND RESULTS: MSCs were isolated from adipose tissue obtained from patients with (i) Atherosclerosis and T2DM (Atherosclerosis+T2DM MSCs, n = 17), (ii) Atherosclerosis without T2DM (Atherosclerosis MSCs, n = 17). MSCs from atherosclerosis+T2DM individuals displayed an inflammatory senescent phenotype and constitutively expressed active forms of effectors of the canonical IKKbeta NF-kappaB inflammatory pathway. Importantly, this constitutive pro-inflammatory IKKbeta signature resulted in an altered secretome and impaired in vitro immunopotency and in vivo healing capacity in an acute MI model. Notably, treatment with a selective IKKbeta inhibitor or IKKbeta knockdown (CRISPR/Cas9-mediated IKKbeta KD) in atherosclerosis+T2DM MSCs reduced the production of pro-inflammatory secretome, increased survival and rescued their immunopotency both in vitro and in vivo. CONCLUSIONS: Constitutively active IKKbeta reduces the immunopotency of atherosclerosis+T2DM MSC by changing their secretome composition. Modulation of IKKbeta in atherosclerosis+T2DM MSCs enhance their myocardial repair ability. CLINICAL PERSPECTIVE: Mesenchymal stromal cells (MSCs) are potent modulators of the immune system and used in clinical trials of inflammatory conditions including atherosclerotic cardiovascular diseases. MSC-secreted bioactive molecules (i.e. secretome) mediate the crosstalk between MSCs and innate/adaptive immune cells. Further, the balance between anti- and pro-inflammatory factors in secretome determines immunopotency. We show that MSCs from diabetic patients with atherosclerosis constitutively express activated forms of the inflammatory effector IKKbeta and NF-kappaB that shifts their secretome towards a pro-inflammatory phenotype and reduces their healing capacity in vivo. Our work emphasizes the importance of proper donor selection and the feasibility of enhancing the immunopotency of atherosclerotic+T2DM-MSC by ex vivo targeting IKKbeta.