Use this URL to cite or link to this record in EThOS:
Title: The anti-inflammatory effects of vitamin D receptor agonists on human white preadipocytes
Author: Zhu, JingJing
ISNI:       0000 0004 6496 5178
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2017
Availability of Full Text:
Access from EThOS:
Access from Institution:
Adipose tissue metaflammation in obesity is characterized by increased infiltration of immune cells and chronically increased gene expression and secretion of pro-inflammatory factors. It is proposed that VDR (vitamin D receptor) agonists could antagonize inflammatory response in adipose tissue. Hence, our study aimed to investigate whether VDR agonists [1α,25(OH)2D3 and its synthesized analogues ZK15922 and ZK191784] could inhibit inflammatory responses stimulated by THP-1-MacCM (macrophage conditioned medium)/IL-1β in human white preadipocytes. Preadipocytes were either cultured alone (control), or with (25%) THP-1-MacCM alone, or with IL-1β (0.5 and 2 ng/ml) alone for 24 h. Further groups of cells were pretreated with VDR agonists [1α,25(OH)2D3 (0.01-10 nM), ZK15922 (10 nM and 1 μM) and ZK191784 (10 nM and 1 μM)] for 24 or 48 h, followed by treatment with (25%) THP-1-MacCM/IL-1β (0.5 and 2 ng/ml) and VDR agonists for a further 24 h before medium and lysate collection. The cell media were collected for measurement of cytokines using arrays and ELISA; the Trizol lysate for qPCR; buffer lysate for western blotting. The results show that THP-1-MacCM/IL-1β enhanced the gene expression and secretion levels of IL-1β, IL-6, IL-8, MCP-1 and RANTES, whilst the pre- and treatment with VDR agonists significantly inhibited the gene expression and secretion of the major inflammatory factors in THP-1-MacCM/IL-1β-stimulated preadipocytes. Moreover, the combination of pretreatment with VDR agonists [1α,25(OH)2D3 (0.01-10 nM), ZK159222 (10 nM and 1μM) and ZK191784 (10 nM and 1μM)] and treatment with VDR agonist-MacCM significantly reduced the inflammatory gene expression and secretion from human preadipocytes, compared with THP-1-MacCM-stimulated preadipocytes. Taken together, VDR agonists could exert anti-inflammatory effects on the pro-inflammatory gene expression and secretion in THP-1-MacCM/IL-1β-stimulated preadipocytes. In addition, VDR agonists significantly reduced the levels of phosphorylated relA of the NF-κB pathway, phosphorylated ERK of the MAPK pathways and phosphorylated eIF-2α of the UPR pathway, whilst increasing methylated relA of the NF-κB pathway and phosphorylated eIF-2α of the UPR pathway in THP-1-MacCM/IL-1β-stimulated preadipocytes. Therefore, it can be speculated that VDR agonists might inhibit metaflammation in adipose tissue by: 1, directly reducing pro-inflammatory gene expression; 2, modulating post-translational relAs and blocking phosphorylated ERK to attenuate pro-inflammatory gene expression; 3, reducing phosphorylated eIF-2α to inhibit the NF-κB pathway; 4, increasing phosphorylated eIF-2α to reduce pro-inflammatory translation.
Supervisor: Wilding, J. P. H. ; Bing, C. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral