Svenja Nellinger (Reutlingen, DE), Sophia Nowakowski (Reutlingen, DE), Prof. Dr. Petra J. Kluger (Reutlingen, DE)
Abstract text (incl. figure legends and references)
Obesity is a complex condition associated with an inflammatory state of the adipose tissue, involving immune cell infiltration and the release of pro-inflammatory cytokines. Therefore, reliable in vitro models resembling inflamed adipose tissue are required as a tool to investigate adipose tissue inflammation and associated diseases. In this study, we set up an inflamed co-culture of the human monocytic cell line MM6 and human primary mature adipocytes encapsulated in gellan gum (GG) cultured in a defined medium. As a linear microbial exopolysaccharide, GG possesses many favorable features such as biocompatibility, biodegradability, and a non-toxic nature. Further favorable properties are its high transparency, thermoresponsive features, flexible mechanical properties, ease of manufacturing and crosslinking, stability under physiological conditions, and low price. Gellan gum itself was neither toxic nor monocyte activating. Successful pro-inflammatory activation of the co-culture by stimulation with phorbol 12-myristate 13-acetate (PMA) and lipopolysaccharide (LPS) was proven by clumping assay of the MM6 and quantification of released cytokines IL1b, IL6 and TNFa. Live/dead staining and visualization of intracellular lipids revealed no impact of activation substances on adipocyte viability and integrity. Further, we transferred the co-culture into perfusion culture to simulate more physiological conditions. Viability and intracellular lipid content were high and morphological (actin, perilipin A) analyses showed similar results for both culture methods. Inflammatory stimuli induced morphological changes independently of the culture condition. For PMA and LPS activation, MM6 exhibited membrane protrusions, and ACs showed decreased perilipin A integrity. In summary, we successfully developed an inflamed human adipose tissue model in a completely defined environment, which can be activated in static and perfusion cultures.