Activation of the PDGFRα-Nrf2 pathway mediates impaired adipocyte differentiation in bone marrow mesenchymal stem cells lacking Nck1

Abstract

Background: The limited options to treat obesity and its complications result from an incomplete understanding of the underlying molecular mechanisms regulating white adipose tissue development, including adipocyte hypertrophy (increase in size) and hyperplasia (increase in number through adipogenesis). We recently demonstrated that lack of the adaptor protein Nck1 in mice is associated with reduced adiposity and impaired adipocyte differentiation. In agreement, Nck1 depletion in 3 T3-L1 cells also attenuates adipocyte differentiation by enhancing PDGFRα activation and signaling. This is accompanied by higher expression of PDGF-A, a specific PDGFRα ligand, that may contribute to enhanced activation of PDGFRα signaling in the absence of Nck1 in white adipose tissue. However, whether Nck1 deficiency also impairs adipogenic differentiation in bone marrow still remains to be determined. Methods: To address this point, Nck1-deficient derived bone marrow mesenchymal stem/stromal cells (BM-MSCs) and C3H10T1/2 mesenchymal stem cells were differentiated into adipocytes in vitro. Genes and proteins expression in these cellular models were determined using qPCR and western blotting respectively. Pharmacological approaches were used to assess a role for Nrf2 in mediating Nck1 deficiency effect on mesenchymal stem cells adipocyte differentiation. Results: Nck1 deficiency in both BM-MSCs and C3H10T1/2 results in impaired adipocyte differentiation, accompanied by increased activation of the transcription factor Nrf2, as shown by increased mRNA levels of Nrf2 target genes, including PDGF-A. Using pharmacological activator and inhibitor of Nrf2, we further provide evidence that Nrf2 is an important player in PDGFRα signaling that mediates expression of PDGF-A and impaired adipogenesis in Nck1-deficient BM-MSCs and C3H10T1/2 cells. Conclusion: This study demonstrates that Nck1 deficiency in mesenchymal stem cells impairs adipogenesis through activation of the PDGFRα-Nrf2 anti-adipogenic signaling pathway.

Novel adipokine asprosin modulates browning and adipogenesis in white adipose tissue

“…Nrf2 also plays an important role in adipogenesis ( Haider & Larose 2020 ). In previous studies, we observed that overexpression of asprosin could reduce the expression of Nrf2, inhibit its activity and downregulate its downstream target genes.…”

Multimodal Label-free Monitoring of Adipogenic Stem Cell Differentiation using Endogenous Optical Biomarkers

“…To further confirm the adipogenic lineage, we investigated the gene expression level of adiponectin [53], leptin [54], and PPARg [55], which were found to be associated with the promotion of adipogenic differentiation. The mRNA fold change of these adipogenic genes were calculated and normalized to cyclophilin B gene by 2 -ΔΔCT method [56,57]. All the gene expression levels increased for hASCs cultured for 9 days in adipogenic media compared to 6 days culture.…”

Effect of Platelet-Derived Growth Factor C on Mitochondrial Oxidative Stress Induced by High d-Glucose in Human Aortic Endothelial Cells

“…Antioxidant protein expression is regulated mainly by the Nrf2/Keap1 pathway [ 13 , 14 , 15 ], which could be initiated by the activation of PDGFRα [ 13 ]. In our conditions, HG seemed to induce the expression of the Nrf2 gene ( Figure 5 A), which could have been related to a compensatory mechanism and a cell-specific antioxidant response [ 16 , 51 ]; similarly, HG increased the Keap1 gene expression at 9 h ( Figure 5 B), which is known for retaining Nrf2 in the cytoplasm [ 52 ].…”

“…Activation of the Nrf2/Keap1 pathway is the primary regulator of antioxidant enzyme expression [ 12 ]. The Nrf2/Keap1 pathway is activated by increased ROS production, which leads to Keap1 oxidation and consequently Nrf2 release and translocation from cytoplasm to the nucleus, where it acts as a transcription factor for antioxidant enzymes [ 13 , 14 , 15 ]. However, the response of Nrf2 under conditions of metabolic stress is weak [ 16 ], so molecules that upregulate this pathway may improve endothelial function in diabetes.…”