MESENCHYMAL STEM CELLS: INNOVATIONS IN INFECTION AND INFLAMMATION THERAPY

Introduction: CF is a genetic disease that impacts sodium and chloride transport across epithelia leading to viscous mucus and pulmonary inflammation and infection; the main cause of morbidity and mortality in this CF. New approaches to reducing inflammation and bacterial burden in CF will minimize the consequences of the disease and improve survival as a cure is pursued. We have published pre-clinical data showing that human bone marrow MSCs may provide a new treatment for CF lung disease by treating pulmonary inflammation and decreasing bacterial burden (S.C. Disc. 3:139). Hypothesis: MSCs secrete products (MSCsup) that impact Pseudomonas aeruginosa (PA) growth and chemokine expression in CF. Methods: Adult bone marrow MSCs (n=4) were obtained with IRB approval. PA growth and kinetics were measured by colony forming units (CFU) and ATP production respectively, with or without geneticin (50µg/ml). MSC pellets were evaluated for MCP-1, IL-6 or IL-8 expression with and without CFTR inhibition (I-172, 10ug/ml), and stimulation with lipopolysaccharide (LPS). Secreted chemokines were evaluated using Luminex Technology. Statistics were done with GraphPad Prism. Results: MSCsup decreased PA growth from 41±3CFU (mean±SEM, n=4) to 21±2 CFU (p=0.0004). Geneticin decreased PA growth to 30±4 CFU, while geneticin with MSCsup decreased PA growth to 15±1 (p<0.009). ATP kinetics of PA versus time had a slope of 36 ±6. Antibiotic treatment decreased PA growth to a slope of 26±6; MSCsups were more potent, decreasing the slope to -51±10 (p<0.001) and when combined with geneticin decreased kinetics to a slope of -68±11. LPS stimulated MSCs expressed MCP-1, IL-8 and IL-6 (1.8±0.4 ddCT, 6.5±0.3ddCT and 4.2±0.9 ddCt compared to control respectively, p≤0.05). Blocking CFTR decreased MCP-1, IL-8 and IL-6 expression compared to baseline, and decreased LPS induced MCP-1 to 0.46±0.2ddCT and 1.72±0.32ddCT respectively compared to unstimulated control(p=0.04). Blocking CFTR did not alter IL-8 expression or LPS response relative to control. MSCsups were evaluated for gene expression showed similar responses in quantified secreted cytokines by Luminex. Conclusions: These studies show: 1) MSCsups decrease PA growth kinetics and enhance antibiotic effectiveness; 2) MSCs produce chemokines that may impact response to infection which are potentially altered in CF MSCs. Summary: MSCsups slow PA growth and enhance antibiotic effectiveness, produce chemokines and impact expression, all important in treating infection and inflammation in CF. These studies suggest MSCs as a therapeutic for CF.