[Effect of PPAR-γ agonist pioglitazone on the prolifeiration of malignant nesothelionma cells induced by HMGB1]

Objective: To investigate the effect and mechanism of PPAR-γ agonist Pioglitazone (PGZ) on the proliferation of malignant mesothelioma (MM) cells. Methods: In December 2019, MM cell lines MSTO-211H and NCI-H2452 were incubated with different final concentrations of PGZ (0, 10, 50, 100, 150, and 200 μmol/L) for different periods of time (24 h, 48 h, and 72 h) , and then the cell proliferation level was detected by CCK8 assay. After given various final concentration of PGZ (0, 10, 50, 100, 150, 200 μmol/L) the for 72 hours, the changes of number and morphology of MM cells were observed under an inverted microscope. The expressions of PPAR-γ and HMGB1 mRNA were determined by real-time fluorescence quantitative reverse transcription-polymerase chain reaction (qRT-PCR) after treatment of MM cells with PGZ of 0, 10, 50, 100 μmol/L for 72 h. The MM cells were treated with PGZ at concentration of 0, 100 μmol/L for 72 h, and the protein expressions of HMGB1 were examined using Western blotting and immunofluorescence; the protein expressions of Ki67 were assessed by immunohistochemistry. Results: The cell viability rate of MM cells was decreased after treated with PGZ (P<0.05) . Cell number in PGZ-treated group was significantly less than that in control group and morphology changes were observed under light microscope. QRT-PCR results revealed significantly increased PPAR-γ mRNA expression in the PGZ-treated group compared to the control group (P<0.05) . There was a significant decrease in the mRNA expression level of HMGB1 in the PGZ-treated group (100 μmol/L) as compared to the control group in MSTO-211H (P<0.05) ; however, the expression level of HMGB1 in NCI-H2452 was an increase or no significant differences (P>0.05) . Western blotting and immunofluorescence results showed that the protein expression of HMGB1 was reduced in the PGZ-treated group compared with the control group in MSTO-211H (P<0.05) , but the protein expression of that in NCI-H2452 was no significant differences (P>0.05) . Immunohistochemistry results showed increased expression of proliferation marker Ki-67. Conclusion: Pioglitazone suppresses the proliferation of MM cells through inhibition of HMGB1 by the activation of PPAR-γ.

Pioglitazone Protects Against Renal Ischemia-Reperfusion Injury via the AMP-Activated Protein Kinase-Regulated Autophagy Pathway

Renal ischemia-reperfusion injury (IRI) is a major cause of acute renal failure. Our previous studies have shown that pioglitazone, a peroxisome proliferators-activated receptor (PPAR)-γ agonist used in type 2 diabetes, protects against renal IRI; however, the molecular mechanism underlying the renoprotective effects of pioglitazone is still unclear. In this study, we investigated the role of AMP-activated protein kinase (AMPK)-regulated autophagy in renoprotection by pioglitazone in IRI. To investigate whether pioglitazone protects renal cells from IRI, an in vivo renal IRI model was used. Cell apoptosis in the kidneys was determined by TUNEL staining. Western blotting was used to determine the expression of AMPK, autophagy-related proteins, and caspase-3/8 proteins in the kidneys. In a rat model of IRI, pioglitazone decreased the increased serum creatinine and urea nitrogen, improved renal histological score, and decreased the cell injury. Pioglitazone also increased AMPK phosphorylation, inhibited p62 and cleaved caspase-3/8 proteins, and activated autophagy-related proteins LC3 II and Beclin-1 in the kidneys of IRI rats. Moreover, GW9662, as a selective inhibitor of PPAR-γ, inhibited the protective effects of pioglitazone. These results suggest that pioglitazone exerts its protective effects in renal IRI via activation of an AMPK-regulated autophagy signaling pathway.

Tagging single nucleotide polymorphisms in the PPAR-γ and RXR-α gene and type 2 diabetes risk: a case-control study of a Chinese Han population

Peroxisome proliferator-activated receptor (PPAR-γ),which is mainly involved in adipocyte differentiation, has been suggested to play an important role in the pathogenesis of insulin resistance and atherosclerosis. We investigated the frequencies of two common tagging polymorphisms of the PPAR-γ gene and two of PPAR-α with minor allele frequency (MAF) ≥0.05 in the Chinese Han population and analyzed the correlation between the different genotypes and the risk of type 2 diabetes mellitus (T2DM). TaqMan® assay was performed to test the genotypes in T2DM patients (n = 1,105) and normal controls (n = 1,107). Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs17817276GG, rs3856806CT and rs3856806CT/TT of PPAR-γ were associated with T2DM, P = 0.023,0.037 and 0.018, respectively. Furthermore, the prevalence of haplotype GT in PPAR-γ was less frequent in the case subjects (0.3%) than in the controls (1.9%) [P < 0.001,OR(95%CI)=0.13 (0.06-0.31)]. Patients with genotype TT of rs3856806 had a higher serum level of adiponectin than those with the genotype CC and CT (P = 0.031 and 0.038, respectively). There was no statistically significant difference between patients and controls in genotype distribution of rs6537944 and rs1045570 of the RXR-α gene. The present study suggests that the variant genotypes in the PPAR-γ gene could decrease the risk for the development of T2DM in the Chinese Han population.