Calcium‐sensing receptor activates the NLRP3 inflammasome in LS14 preadipocytes mediated by ERK1/2 signaling

Abstract

The study of the mechanisms that trigger inflammation in adipose tissue is key to understanding and preventing the cardiometabolic consequences of obesity. We have proposed a model where activation of the G protein-coupled calcium sensing receptor (CaSR) leads to inflammation and dysfunction in adipose cells. Upon activation, CaSR can mediate the expression and secretion of proinflammatory factors in human preadipocytes, adipocytes, and adipose tissue explants. One possible pathway involved in CaSR-induced inflammation is the activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome, that promotes maturation and secretion of interleukin (IL)-1β. The present work aimed to study whether CaSR mediates the activation of NLRP3 inflammasome in the human adipose cell model LS14. We assessed NLRP3 inflammasome priming and assembly after cinacalcet-induced CaSR activation and evaluated if this activation is mediated by downstream ERK1/2 signaling in LS14 preadipocytes. Exposure to 2 μM cinacalcet elevated mRNA expression of NLRP3, CASP-1, and IL-1β, as well as an increase in pro-IL-1β protein. In addition, CaSR activation triggered NLRP3 inflammasome assembly, as evidenced by a 25% increase in caspase-1 activity and 63% IL-1β secretion. CaSR silencing (siRNA) abolished the effect. Upstream ERK pathway inhibition decreased cinacalcet-dependent activation of NLRP3 inflammasome. We propose CaSR-dependent NLRP3 inflammasome activation in preadipocytes through ERK signaling as a novel mechanism for the development of adipose dysfunction, that may favor the cardiovascular and metabolic consequences of obesity. To the best of our knowledge, this is the first report linking the inflammatory effect of CaSR to NLRP3 inflammasome induction in adipose cells.

Prokineticin 2 via Calcium-Sensing Receptor Activated NLRP3 Inflammasome Pathway in the Testicular Macrophages of Uropathogenic Escherichia coli-Induced Orchitis

“…CaSR is expressed in BMDNs, promotes the assembly of NLRP3 inflammasomes by regulating Ca 2+ concentration, and modulates the secretion and maturation of IL-1b (15). CaSR activates NLRP3 inflammasomes through the ERK1/2 signaling pathway in the preadipocyte line LS14 (16). However, the role of CaSR in UPEC-induced orchitis macrophages remains unclear.…”

Calcium-Sensing Receptor in Adipose Tissue: Possible Association with Obesity-Related Elevated Autophagy

“…To explore the mechanism through which CaSR modulates autophagy, we evaluated the ERK 1/2 pathway, given our previous reports of the relevance of this pathway in CaSR signaling in the human LS14 preadipocyte cell line [ 13 , 14 ]. We performed control experiments to assess ERK1/2 inhibition with the upstream (MEK1) ERK inhibitor U0126 in whole AT, primary in vitro differentiated adipocytes (not shown) and primary preadipocytes, observing ample variability and difficulty in obtaining good data in the first two and the best results in the latter.…”

“…This may reflect the well-described biased agonism of CaSR activation [ 11 , 12 , 46 ], which has been documented for polyamines toward ERK1/2 signaling in HEK293-CaSR cells [ 46 ]. Our previous reports showed that CaSR activation by cinacalcet triggers ERK1/2 pathway to regulate preadipocyte proliferation [ 13 ] and inflammasome activation [ 14 ]; however, this pathway probably does not mediate the effect on autophagy. The specific pathway involved in cinacalcet autophagy modulation remains to be elucidated.…”

“…Multiple intracellular pathways can be triggered depending on the receptor’s conformational state induced by a given CaSR ligand, a phenomenon called biased agonism [ 11 , 12 ]. In preadipocytes, the allosteric CaSR activator cinacalcet induces ERK1/2 activation, resulting in cell proliferation and NLRP3 induction [ 13 , 14 ]. CaSR activation by the polyamine spermine and/or the calcimimetic cinacalcet in preadipocytes, adipocytes and whole adipose tissue is associated with inflammation, adipogenesis, proliferation, as well as impaired lipid handling [ 3 , 13 , 14 , 15 , 16 , 17 ].…”

Calcium‐sensing receptor mediates interleukin‐1β‐induced collagen expression in mouse collecting duct cells

“…Moreover, in vitro experiments performed in LS14 preadipocytes proved that ERK1/2 signaling is involved in the cellular proliferation and NLRP3 activation induced by CaSR stimulation. 19 In the current study, we further evaluated whether the nuclear translocation of β-catenin is implicated in CaSRmediated collagen expression in CD cells treated with IL-1β. As the data show, we observed that the specific CaSR inhibitors (Calhex231, NPS2143, or CaSR siRNA) could partially attenuate the IL-1β-induced nuclear translocation of β-catenin in CD cells.…”