scholarly journals Pro-inflammatory signaling by 24,25-dihydroxyvitamin D3 in HepG2 cells

2016 ◽  
Vol 57 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Kent Wehmeier ◽  
Luisa M Onstead-Haas ◽  
Norman C W Wong ◽  
Arshag D Mooradian ◽  
Michael J Haas

The vitamin D metabolite 24,25-dihydroxyvitamin D3(24, 25[OH]2D3) was shown to induce nongenomic signaling pathways in resting zone chondrocytes and other cells involved in bone remodeling. Recently, our laboratory demonstrated that 24,25-[OH]2D3but not 25-hydroxyvitamin D3, suppresses apolipoprotein A-I (apo A-I) gene expression and high-density lipoprotein (HDL) secretion in hepatocytes. Since 24,25-[OH]2D3has low affinity for the vitamin D receptor (VDR) and little is known with regard to how 24,25-[OH]2D3modulates nongenomic signaling in hepatocytes, we investigated the capacity of 24,25-[OH]2D3to activate various signaling pathways relevant to apo A-I synthesis in HepG2 cells. Treatment with 24,25-[OH]2D3resulted in decreased peroxisome proliferator-activated receptor alpha (PPARα) expression and retinoid-X-receptor alpha (RXRα) expression. Similarly, treatment of hepatocytes with 50 nM 24,25-[OH]2D3for 1–3 h induced PKCα activation as well as c-jun-N-terminal kinase 1 (JNK1) activity and extracellular-regulated kinase 1/2 (ERK1/2) activity. These changes in kinase activity correlated with changes in c-junphosphorylation, an increase in AP-1-dependent transcriptional activity, as well as repression of apo A-I promoter activity. Furthermore, treatment with 24,25-[OH]2D3increased IL-1β, IL-6, and IL-8 expression by HepG2 cells. These observations suggest that 24,25-[OH]2D3elicits several novel rapid nongenomic-mediated pro-inflammatory protein kinases targeting AP1 activity, increasing pro-inflammatory cytokine expression, potentially impacting lipid metabolism and hepatic function.

Author(s):  
Vishal Arvind Chakkarwar ◽  
Pravin Kawtikwar

Objective: The present study investigated the possible effect of fenofibrate and gemfibrozil peroxisome proliferator-activated receptor-alpha agonist in diabetes-induced acute kidney injury (AKI) in rats.Methods: Rats were administered streptozotocin (STZ) (50 mg/kg, i.p., single dose) to induce experimental diabetes mellitus. The development of diabetic AKI was assessed biochemically and histologically. In addition, the diabetes-induced lipid profile and renal oxidative stress were assessed. The single dose of STZ produced diabetes, which induced renal oxidative stress, altered the lipid profile and subsequently produced kidney injuryAKI in 7 weeks by increasing serum creatinine, blood urea nitrogen (BUN), proteinuria, and glomerular damage. Treatment with fenofibrate and gemfibrozil (30 mg/kg p.o, 7 weeks) normalized the altered lipid profile by decreasing serum cholesterol, triglycerides, and increasing serum high-density lipoprotein in diabetic rats. Lisinopril (1 mg/kg, p.o., 7 weeks, reference compound) prevents lipid alteration and development of diabetic AKI.Result: Fenofibrate and gemfibrozil, besides hyperglycemia, significantly prevented the development of diabetic AKI by reducing (serum and tissue) oxidative stress, hyperlipidemia, serum BUN, creatinine, and urinary protein. Further, fenofibrate, but not gemfibrozil, considerably reduced renal structural and functional abnormalities in diabetic rats. The fenofibrate was more effective in attenuating the diabetes-induced AKI and renal oxidative stress as compared to treatment with and gemfibrozil.Conclusion: The fenofibrate and gemfibrozil treatment markedly prevented the diabetes-induced AKI. In comparison, the fenofibrate is found to be a superior approach to attenuate the diabetic AKI than gemfibrozil.


Author(s):  
Vishal Arvind Chakkarwar ◽  
Pravin Kawtikwar

Objective: The present study investigated the possible effect of fenofibrate and gemfibrozil peroxisome proliferator-activated receptor-alpha agonist in diabetes-induced acute kidney injury (AKI) in rats.Methods: Rats were administered streptozotocin (STZ) (50 mg/kg, i.p., single dose) to induce experimental diabetes mellitus. The development of diabetic AKI was assessed biochemically and histologically. In addition, the diabetes-induced lipid profile and renal oxidative stress were assessed. The single dose of STZ produced diabetes, which induced renal oxidative stress, altered the lipid profile and subsequently produced kidney injuryAKI in 7 weeks by increasing serum creatinine, blood urea nitrogen (BUN), proteinuria, and glomerular damage. Treatment with fenofibrate and gemfibrozil (30 mg/kg p.o, 7 weeks) normalized the altered lipid profile by decreasing serum cholesterol, triglycerides, and increasing serum high-density lipoprotein in diabetic rats. Lisinopril (1 mg/kg, p.o., 7 weeks, reference compound) prevents lipid alteration and development of diabetic AKI.Result: Fenofibrate and gemfibrozil, besides hyperglycemia, significantly prevented the development of diabetic AKI by reducing (serum and tissue) oxidative stress, hyperlipidemia, serum BUN, creatinine, and urinary protein. Further, fenofibrate, but not gemfibrozil, considerably reduced renal structural and functional abnormalities in diabetic rats. The fenofibrate was more effective in attenuating the diabetes-induced AKI and renal oxidative stress as compared to treatment with and gemfibrozil.Conclusion: The fenofibrate and gemfibrozil treatment markedly prevented the diabetes-induced AKI. In comparison, the fenofibrate is found to be a superior approach to attenuate the diabetic AKI than gemfibrozil.


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