A three-dimensional human adipocyte model of fatty acid-induced obesity

Abstract

Obesity prevalence has reached pandemic proportions, leaving individuals at high risk for the development of diseases such as cancer and type 2 diabetes. In obesity, to accommodate excess lipid storage, adipocytes become hypertrophic, which is associated with an increased pro-inflammatory cytokine secretion and dysfunction of metabolic processes such as insulin signaling and lipolysis. Targeting adipocyte dysfunction is an important strategy to prevent the development of obesity-associated disease. However, it is unclear how accurately animal models reflect human biology, and the long-term culture of human hypertrophic adipocytes in an in vitro 2D monolayer is challenging due to the buoyant nature of adipocytes. Here we describe the development of a human 3D in vitro disease model that recapitulates hallmarks of obese adipocyte dysfunction. First, primary human adipose-derived mesenchymal stromal cells are embedded in hydrogel, and infiltrated into a thin cellulose scaffold. The thin microtissue profile allows for efficient assembly and image-based analysis. After adipocyte differentiation, the scaffold is stimulated with oleic or palmitic acid to mimic caloric overload. Using functional assays, we demonstrated that this treatment induced important obese adipocyte characteristics such as a larger lipid droplet size, increased basal lipolysis, insulin resistance and a change in macrophage gene expression through adipocyte-conditioned media. This 3D disease model mimics physiologically relevant hallmarks of obese adipocytes, to enable investigations into the mechanisms by which dysfunctional adipocytes contribute to disease.

Alternative Methods as Tools for Obesity Research: In Vitro and In Silico Approaches

“…It was demonstrated that the adipocytes presented with larger lipid droplets and metabolic profiles compatible with hypertrophy, such as increased basal lipolysis and insulin resistance. Thus it proves to be a valuable tool in the studies of adipocyte dysfunctions because of obesity [ 116 ].…”

Unraveling White Adipose Tissue Heterogeneity and Obesity by Adipose Stem/Stromal Cell Biology and 3D Culture Models

“…Recently, Pieters and collaborators (2022) treated human ASC embedded into hydrogel with fatty acids after adipogenic differentiation. The resulting adipocytes showed obese characteristics such as hypertrophy, increased lipolysis, and insulin resistance [ 103 ]. The phenomenon of lipolysis is commonly described in fat depots with more inflammatory properties, such as VAT [ 104 ].…”

Development and analysis of scaffold-free adipose spheroids

“…In the past 10 years, several new models of adipose tissue have been developed with varying degrees of complexity [ 11 ]. Many of these models support the 3D environment through the use of scaffolds, such as silk [ 12 , 13 ], Matrigel [ 14 ] or Geltrex [ 15 ], collagen [ 16 ], and fibrinogen [ 17 ]. More recently, efforts have been made to increase the complexity of adipose models by including other cell lineages that are found in native adipose tissue.…”