Mature Human White Adipocytes Cultured under Membranes Maintain Identity, Function, and Can Transdifferentiate into Brown-like Adipocytes

Matthew J Harms,Qian Li,Sunjae Lee,Cheng Zhang,Bengt Kull,Stefan Hallen,Anders Thorell,Ida Alexandersson,Carolina E Hagberg,Xiao-Rong Peng,Adil Mardinoglu,Kirsty L Spalding,Jeremie Boucher

doi:10.1016/j.celrep.2019.03.026

Abstract

White adipose tissue (WAT) is a central factor in the development of type 2 diabetes, but there is a paucity of translational models to study mature adipocytes. We describe a method for the culture of mature white adipocytes under a permeable membrane. Compared to existing culture methods, MAAC (membrane mature adipocyte aggregate cultures) better maintain adipogenic gene expression, do not dedifferentiate, display reduced hypoxia, and remain functional after long-term culture. Subcutaneous and visceral adipocytes cultured as MAAC retain depot-specific gene expression, and adipocytes from both lean and obese patients can be cultured. Importantly, we show that rosiglitazone treatment or PGC1α overexpression in mature white adipocytes induces a brown fat transcriptional program, providing direct evidence that human adipocytes can transdifferentiate into brown-like adipocytes. Together, these data show that MAAC are a versatile tool for studying phenotypic changes of mature adipocytes and provide an improved translational model for drug development.

Highlights

Adipose tissue plays a central role in the development of insulin resistance and type 2 diabetes (T2D)
We found that membrane mature adipocyte aggregate cultures (MAAC) are superior to other culture methods at preserving mature adipocyte identity and function
MAAC Preserve an Adipocyte Gene Signature Mature adipocytes isolated from the subcutaneous adipose tissue of 6-week-old CD1 mice were directly pipetted onto the underside of a membrane and lowered into a well containing medium (Figure 1A; Figure S6)

Summary

Introduction

Adipose tissue plays a central role in the development of insulin resistance and type 2 diabetes (T2D). Adipocytes undergo hypertrophy to clear lipids from circulation; this finite lipid-buffering capacity can become exhausted, leading to lipid accumulation in non-adipose tissues (Guilherme et al, 2008; Lotta et al, 2017; Rosen and Spiegelman, 2014; Samuel and Shulman, 2012) This limited storage capacity of adipocytes and subsequent overflow of lipids into other tissues has been identified as a key etiological and genetic component in the development of diabetes and insulin-resistant cardiometabolic disease (Lotta et al, 2017). Another attractive therapeutic avenue for treating T2D is transforming energy-storing white adipocytes into thermogenic brown-like adipocytes or activating uncoupling protein 1 (UCP1) in existing brown adipose tissue (BAT) (Harms and Seale, 2013)

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Discussion

Conclusion