Irisin Stimulates the Release of CXCL1 From Differentiating Human Subcutaneous and Deep-Neck Derived Adipocytes via Upregulation of NFκB Pathway

Abstract

Thermogenic brown and beige adipocytes might open up new strategies in combating obesity. Recent studies in rodents and humans have indicated that these adipocytes release cytokines, termed “batokines”. Irisin was discovered as a polypeptide regulator of beige adipocytes released by myocytes, primarily during exercise. We performed global RNA sequencing on adipocytes derived from human subcutaneous and deep-neck precursors, which were differentiated in the presence or absence of irisin. Irisin did not exert an effect on the expression of characteristic thermogenic genes, while upregulated genes belonging to various cytokine signaling pathways. Out of the several upregulated cytokines, CXCL1, the highest upregulated, was released throughout the entire differentiation period, and predominantly by differentiated adipocytes. Deep-neck area tissue biopsies also showed a significant release of CXCL1 during 24 h irisin treatment. Gene expression data indicated upregulation of the NFκB pathway upon irisin treatment, which was validated by an increase of p50 and decrease of IκBα protein level, respectively. Continuous blocking of the NFκB pathway, using a cell permeable inhibitor of NFκB nuclear translocation, significantly reduced CXCL1 release. The released CXCL1 exerted a positive effect on the adhesion of endothelial cells. Together, our findings demonstrate that irisin stimulates the release of a novel adipokine, CXCL1, via upregulation of NFκB pathway in neck area derived adipocytes, which might play an important role in improving tissue vascularization.

BMP7 Increases UCP1-Dependent and Independent Thermogenesis with a Unique Gene Expression Program in Human Neck Area Derived Adipocytes

“…Recently, we screened and compared global gene expression patterns by RNA-sequencing of human primary differentiated adipocytes derived from progenitors of DN and subcutaneous neck (SC) origins [27,28]. Consistent with previous studies [26,[29][30][31][32], DN derived adipocytes displayed higher browning features than the SC derived ones.…”

“…Patients with known diabetes, abnormal thyroid hormone levels or malignant tumors were not included in this study. Written informed consent was obtained from all participants prior surgery [27,28,74,75].…”

Mitophagy Mediates the Beige to White Transition of Human Primary Subcutaneous Adipocytes Ex Vivo

“…Cells were collected in Trizol reagent (Thermo Fisher Scientific, Waltham, MA, USA), followed by manual isolation of RNA and DNA by chloroform extraction and isopropanol or ethanol precipitation, respectively. RNA quality was evaluated by Nanodrop (Thermo Fisher Scientific), and cDNA was generated by a TaqMan reverse transcription reagent kit (Thermo Fisher Scientific) followed by qPCR analysis [ 37 , 91 ]. Gene expression was normalized to GAPDH .…”

“…Sample separation was performed by SDS-PAGE, followed by transfer to a PVDF membrane. The membrane was blocked by 5% skimmed milk solution [ 37 , 91 ]. The following primary antibodies were used: anti-UCP1 (1:750, R&D Systems, Minneapolis, MN, USA, MAB6158), anti-p62 (1:5000, Novus Biologicals, Centennial, CO, USA, NBP1-49956), anti-LC3 (1:2000, Novus Biologicals, NB100-2220), anti-Parkin (1:750, Santa Cruz Biotechnology, Dallas, TX, USA, sc-32282), anti-NBR1 (1:1000, Novus Biologicals, NBP1-71703), and anti-β-actin (1:5000, A2066).…”

Mitophagy mediates beige to white transition of human primary subcutaneous adipocytes ex vivo

“…Cells were collected in Trizol reagent (Thermo Fisher Scientific, Waltham, MA, USA) followed by manual isolation of RNA and DNA by chloroform extraction and isopropanol or ethanol precipitation, respectively. RNA quality was evaluated by Nanodrop (Thermo Fisher Scientific), and cDNA was generated by TaqMan reverse transcription reagent kit (Thermo Fisher Scientific) followed by qPCR analysis [39,84]. Gene expression was normalized to GAPDH.…”