HAND2 is a novel obesity-linked adipogenic transcription factor regulated by glucocorticoid signalling

Abstract

Aims/hypothesis Adipocytes are critical cornerstones of energy metabolism. While obesity-induced adipocyte dysfunction is associated with insulin resistance and systemic metabolic disturbances, adipogenesis, the formation of new adipocytes and healthy adipose tissue expansion are associated with metabolic benefits. Understanding the molecular mechanisms governing adipogenesis is of great clinical potential to efficiently restore metabolic health in obesity. Here we investigate the role of heart and neural crest derivatives-expressed 2 (HAND2) in adipogenesis. Methods Human white adipose tissue (WAT) was collected from two cross-sectional studies of 318 and 96 individuals. In vitro, for mechanistic experiments we used primary adipocytes from humans and mice as well as human multipotent adipose-derived stem (hMADS) cells. Gene silencing was performed using siRNA or genetic inactivation in primary adipocytes from loxP and or tamoxifen-inducible Cre-ERT2 mouse models with Cre-encoding mRNA or tamoxifen, respectively. Adipogenesis and adipocyte metabolism were measured by Oil Red O staining, quantitative PCR (qPCR), microarray, glucose uptake assay, western blot and lipolysis assay. A combinatorial RNA sequencing (RNAseq) and ChIP qPCR approach was used to identify target genes regulated by HAND2. In vivo, we created a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter (Hand2AdipoqCre) and performed a large panel of metabolic tests. Results We found that HAND2 is an obesity-linked white adipocyte transcription factor regulated by glucocorticoids that was necessary but insufficient for adipocyte differentiation in vitro. In a large cohort of humans, WAT HAND2 expression was correlated to BMI. The HAND2 gene was enriched in white adipocytes compared with brown, induced early in differentiation and responded to dexamethasone (DEX), a typical glucocorticoid receptor (GR, encoded by NR3C1) agonist. Silencing of NR3C1 in hMADS cells or deletion of GR in a transgenic conditional mouse model results in diminished HAND2 expression, establishing that adipocyte HAND2 is regulated by glucocorticoids via GR in vitro and in vivo. Furthermore, we identified gene clusters indirectly regulated by the GR–HAND2 pathway. Interestingly, silencing of HAND2 impaired adipocyte differentiation in hMADS and primary mouse adipocytes. However, a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter did not mirror these effects on adipose tissue differentiation, indicating that HAND2 was required at stages prior to Adipoq expression. Conclusions/interpretation In summary, our study identifies HAND2 as a novel obesity-linked adipocyte transcription factor, highlighting new mechanisms of GR-dependent adipogenesis in humans and mice. Data availability Array data have been submitted to the GEO database at NCBI (GSE148699). Graphical abstract

Adipocyte function and the development of cardiometabolic disease

“…Over the years, many more transcriptional regulators of adipocyte differentiation have been discovered, including some that are expressed by both adipocytes and cells of the cardiovascular system, such as heart‐ and neural crest derivatives‐expressed protein 2 (HAND2) (Giroud et al . Diabetologia 2021). Overall, the ability of adipocytes to properly differentiate and function is critical to prevent dyslipidaemia and CVD.…”

Genomic and Non-Genomic Actions of Glucocorticoids on Adipose Tissue Lipid Metabolism

“…GCs can affect adipocytes differently based on the differentiation status of cells. For example, in preadipocytes, GC-GR binding can lead to the activation of heart and neural crest derivatives expressed 2 (HAND2), a transcription factor necessary for early adipocyte differentiation [118]. Silencing HAND2 prevents commitment to the adipose lineage in human stem cells and downregulates lipid metabolism genes, such as HSL.…”

The obesity-linked human lncRNA AATBC regulates adipocyte plasticity by stimulating mitochondrial dynamics and respiration

“…Protein expression was investigated using western blot as described previously [53]. Cells were lysed in RIPA buffer (150 mM NaCl, 5 mM EDTA, 50 mM Tris pH 8, 0.1 % w/v SDS, 1 % w/v IGEPAL® CA-630, 0.5 % w/v sodium deoxycholate) containing protease inhibitors (Sigma) in a 1:100 v/v ratio.…”

“…Human multipotent adipose derived stem (hMADS) cells were cultured as previously described [53]. Briefly, cells were kept until confluency in proliferation medium (Dulbecco's Modified Eagle's Medium (DMEM), (Lonza, Switzerland # BE12-707F) supplemented with 10 % FBS (Sigma, Germany), 10 mmol/l 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) (Gibco, Germany #15630056), 2.5 ng/ml human fibroblast growth factor-basic (hFGF2) (PeproTech, Germany #100-18B), 50 mg/ml penicillin, and 50 mg/ml streptomycin (Gibco, Germany #15140122), followed by 48 h of incubation without hFGF2.…”

“…The acquisition of human data from cohorts 1 and 2 has been previously described [53]. Briefly, cohort 1 includes 318 individuals (249 female individuals, 69 male individuals; BMI range: 21.9 -97.3 kg/m 2 , age range: 19-75 years) undergoing elective laparoscopic surgery during which subcutaneous (scWAT) and visceral, omental (visWAT) adipose depots were obtained.…”