Effects of PPARγ, agonist on the expression of PPARγ. toll-like receptor 4 and STAT1 signal protein activation in rats with peritoneal dialysis-related acute peritonitis / 中华肾脏病杂志

Objective To explore the effects of peroxisome proliferator-activated receptorγ (PPARγ) agonist rosiglitazone and 15-deoxy-delta-12,14-prostaglandin J2 (15d-PGJ2) on the expression of PPARγ, toll-like receptor 4 (TLR4) and the activation of STAT1 as well as the local inflammation reaction of abdominal cavity in sprague dawley (SD) rats with peritoneal dialysis- related acute peritonitis induced by lipopolysaccharide (LPS). Methods Twenty-four male SD rats were equally randomized to four groups(n=6 each): control group, injected with 4.25% dextrose peritoneal dialysate (PDF) via abdominal cavity(90 ml/kg); LPS group, injected with LPS(1 mg/kg) via abdominal cavity 4 hours later follewed by PDF injection; rosiglitazone plus LPS group (Rosi group), preconditioned with rosiglitazone (20 mg·kg-1·d-1) by intragastric way for 3 days, then injected with LPS and PDF via abdominal cavity; 15d-PGJ2 plus LPS group (15d-PGJ2 group), preconditioned with 15d-PGJ2 (0.3 mg·kg-1·d-1)via abdominal cavity injection for 3 days, then injected with LPS and PDF via abdominal cavity. The rats were killed 4 hours after PDF injection, IL-6 level in abdominal dropsy was determined by ELISA. Peritoneum tissue was stained by Masson. Leucocyte count in abdominal dropsy was performed. The mRNA expression of PPARγ and TLR4 in peritoneum tissue was determined by RT-PCR; the protein expression of PPARγ, TLR4, p-STAT1 and STAT1 in peritoneum tissue was analyzed by Western blot. Results IL-6 level of abdominal dropsy in LPS group [median 268.53 (range 201.87-335.19) ng/L] was significantly higher than that of control group [median 147.62 (range 130.60-164.64) ng/L] (P<0.01). The IL-6 level of abdominal dropsy in Rosi group [median 110.20 (range 77.60-142.80) ng/L] was significantly lower than that of LPS group (P<0.05). Compared to that of control group, the edematous degree of peritoneum in LPS group was significantly severer, meanwhile, mRNA and proteins expression of PPARγ and TLR4 in rat peritoneum were also significantly higher (P<0.05, P<0.01). Compared to that of LPS group, the edematous degree of peritoneum in Rosi group was lighter, the expression of PPARγ and TLR4 mRNA was significantly up-regulated (P<0.05), meanwhile their proteins expression was down-regulated (P<0.05); and in 15d-PGJ2 group, the edematous degree of peritoneum, the expression of PPARγ mRNA and protein was also decreased (P<0.05), but TLR4 mRNA expression was up-regulated (P<0.01), however, its protein expression was down-regulated (P<0.05). There were no significant differences in leucocyte count of abdominal dropsy among the four groups. The p-STAT1 expression in the rats peritoneum induced by LPS was markedly increased by both rosiglitazone and 15d-PGJ2 (P<0.01). Conclusions Both rosiglitazone and 15d-PGJ2 can down-regnlate the inflammatory reaction in rat peritonitis induced by LIPS, which may be involved in modulating the expression of associated functional protein during LPS signal pathway.

15-Deoxy-Delta(12,14)-Prostaglandin J2 and Proinflammatory Cytokines in IgA Nephropathy / 대한신장학회지

PURPOSE: This study was performed to demonstrate a correlation among urinary 15d-PGJ2, proinflammatory cytokines (i.e. IL-23, IL-6, and TGF-beta1), and CRP, and to determinate the contributors to prognostic score and proteinuria in IgAN patients. METHODS: Fifty-four patients with biopsy-proven IgAN were enrolled. For comparison with IgAN, five MCD patients were also enrolled. Immunohistochemical staining for PPAR-gamma in kidney tissue and measurements of urinary IL-6, IL-23, TGF-beta1, 15d-PGJ2 and serum CRP were performed RESULTS: There was no difference according to PPAR-gamma staining. 15d-PGJ2 was negatively correlated with urinary IL-23, TGF-beta1, and CRP. Among proinflammatory cytokines and CRP, there were positive relationships with each other except for IL-23 and CRP. TGF-beta1 in the group having proteinuria more than 3 g/day was statistically higher than that in the sole hematuria group. However, in multivariate regression analysis, not a single relation was found between TGF-beta1 and proteinuria. Prognostic score was correlated with IL-6, IL-23, TGF-beta1, CRP, 15d-PGJ2, and 24hr proteinuria. 24hr proteinuria was correlated with IL-6 and 15d-PGJ2. In multivariate regression analysis, CRP, 15d-PGJ2, and 24hr proteinuria contributed to prognostic score, and only 15d-PGJ2 contributed to 24hr proteinuria. Last, urinary 15d-PGJ2 in IgAN was higher than that in MCD. CONCLUSION: Endogenous 15d-PGJ2 was associated with inflammation and might be considered as a material which could delay the damage of kidney in IgAN. In the future, larger cohort and long-term follow-up studies are needed to demonstrate the role of 15d-PGJ2 as prognostic indicator or marker of kidney damage.

15-Deoxy-delta12,14-PGJ2inhibits IL-6-induced Stat3 phosphorylation in lymphocytes

15-deoxy-delta12,14-PGJ2(15d-PGJ2) is a natural ligand that activates the peroxisome proliferators-activated receptor (PPAR) gamma, a member of nuclear receptor family implicated in regulation of lipid metabolism and adipocyte differentiation. Recent studies have shown that 15d-PGJ2 is the potent anti-inflammatory agent functioning via PPARgamma-dependent and -independent mechanisms. Most postulated mechanisms for anti-inflammatory action of PPARgamma agonists are involved in inhibiting NF-kappaB signaling pathway. We examined the possibility that IL-6 signaling via the Jak-Stat pathway is modulated by 15d-PGJ2 in lymphocytes and also examined whether the inhibition of IL-6 signaling is dependent of PPARgamma. 15d-PGJ2 blocked IL-6 induced Stat1 and Stat3 activation in primary human lymphocytes, Jurkat cells and immortalized rheumatoid arthritis B cells. Inhibition of IL-6 signaling was induced rapidly within 15 min after treatment of 15d-PGJ2. Other PPARgamma-agonists, such as troglitazone and ciglitazone, did not inhibit IL-6 signaling, indicating that 15d-PGJ2 affect the IL-6-induced Jak-Stat signaling pathway via PPARgamma-independent mechanism. Although cycloheximide reversed 15d-PGJ2-mediated inhibition of Stat3 activation, actinomycin D had no effect on 15d-PGJ2-mediated inhibition of IL-6 signaling, indicating that inhibition of IL-6 signaling occur independent of de novo gene expression. These results show that 15d-PGJ2 specifically inhibit Jak-Stat signaling pathway in lymphocytes, and suggest that 15d-PGJ2 may regulate inflammatory reactions through the modulation of different signaling pathway other than NF-kappaB in lymphocytes.