Introduction: eGWAS implicates the immune-cell receptor CD44 as the top candidate gene in the molecular pathogenesis of T2D1. We have shown that in human adipose tissue, CD44 expression is associated with inflammatory gene expression, M1 macrophage phenotype, and systemic insulin resistance2. Here we sought to determine whether CD44 directly impairs adipocyte function via siRNA knockdown in human preadipocytes with quantification of proliferation, differentiation, and gene expression.
Methods: Abdominal subcutaneous adipose tissue was harvested from five healthy nondiabetic obese individuals during bariatric surgery. Preadipocytes were isolated via collagenase digestion and seeded at 1×10^4 cells/well and treated with siRNA-CD44 or mock condition (control) using siRNA Maxi Transfection Reagents (Invitrogen). Cell proliferation was assayed by MTS (Promega) on Days 1, 2, 3 post transfection. Differentiation was induced at confluence (as described3), and cells were harvested at days 3, 6, 12 after confluence for gene expression and at day 12 for oil red O staining (total lipid uptake) and immunofluorescence microscopy (% differentiation = bodipy/dapi*100).
Results: CD44 knockdown decreased preadipocyte proliferation and increased adipocyte differentiation and lipid uptake.
Conclusion: CD44 may contribute to human insulin resistance by impairing adipocyte differentiation and fat storage.
H.Chen: None. N.R.Saini: None. E.M.Ayhan: None. T.Mclaughlin: Board Member; January, Inc., Research Support; Merck & Co., Inc., Stock/Shareholder; Eiger Bio.
National Institutes of Health (1R21AI159024-01A1)
