Differentiation of primary pre‐adipocytes into adipose tissue in a microfluidic chip

The growing problem of obesity has reached epidemic proportion worldwide and with over 1.5 billion adults aged 20 years and older characterized as being overweight [1]. Being overweight or obese remarkably increases the risks of developing other metabolic diseases such as diabetes. Adipose tissue is a key player in metabolic disorders including obesity and diabetes. Recent studies highlight the critical role adipose plays in maintaining metabolic homeostasis [2, 3]. Development of in vitro models of adipose tissue is highly desirable to improve our understanding of disease biology of obesity and metabolic diseases. Microfluidic on‐chip in vitro models offer advantages compared to traditional static culture system in terms of mimicking the complex physiological environment for culturing, differentiating, and stimulating adipocytes in a small‐volume perfused cell culture system [4, 5]. Here, we aim to establish a model for differentiation of pre‐adipocytes into mature adipose depots on a microfluidic chip. Mouse primary pre‐adipocytes isolated from subcutaneous white adipose tissue (WAT) were differentiated into mature white adipocytes in a microfluidic chip under perfused flow of 5 μ L/h. Our unique microfluidic chip enables for long‐term culture of cells and allows stimulation of cells through perfusion – we can culture, differentiate, and maintain the differentiated adipose tissue for over 21 days in the device. Upon differentiation, the cells increasingly accumulated triglycerides, which was quantified using fluorescence microscopy. Further confirmation of the differentiation was assessed by measuring the gene expression of markers including leptin and adiponectin. In addition, we collected and analyzed the perfusate for adipose secretions including adiponectin. Our results indicate an improved understanding of adipose differentiation under dynamic conditions and can serve as disease models for obesity and other metabolic disorders. Support or Funding Information This work was supported by NIH grant DK095984. [1] Ahima RS. Digging deeper into obesity. Journal of Clinical Investigation 2011;121:2076–9.[2] Clark AM, Sousa KM, Chisolm CN, MacDougald OA, Kennedy RT. Reversibly sealed multilayer microfluidic device for integrated cell perfusion and on‐line chemical analysis of cultured adipocyte secretions. Analytical and Bioanalytical Chemistry 2010;397:2939–47.[3] Lee PL, Tang Y, Li H, Guertin DA. Raptor/mTORC1 loss in adipocytes causes progressive lipodystrophy and fatty liver disease. Molecular Metabolism 2016;5:422–32.[4] Engler AJ, Hemmingsen M, Vedel S, Skafte‐Pedersen P, Sabourin D, Collas P, et al. The Role of Paracrine and Autocrine Signaling in the Early Phase of Adipogenic Differentiation of Adipose‐derived Stem Cells. PLoS ONE 2013;8:e63638.[5] Godwin LA, Brooks JC, Hoepfner LD, Wanders D, Judd RL, Easley CJ. A microfluidic interface for the culture and sampling of adiponectin from primary adipocytes. The Analyst 2015;140:1019–25.