PPARfJ involved in endothelial cell injury induced by high glucose via nitrative stress / 中国药理学通报

Aim To investigate the role of PPARβ and nitrative stress in human umbilical vein endothelial cells(HUVECs)injury induced by high glucose.Methods The cell viability was detected by CCK-8.The cell proliferation was detected by EdU proliferation detection kit.The protein expression level of PPARβ,eNOS,iNOS,and 3-nitrotyrosine was detected by Western blot.The content of peroxynitrite and nitric oxide(NO)was determined by peroxynitrite kit and Griess Reagent,respectively.Results Glucose(30,40,50 mmol·L-1)significantly reduced the cell viability of HUVECs in a dose-dependent manner.Glucose at 30 mmol·L-1(high glucose,HG)significantly reduced the proliferation of HUVECs,down-regulated the expression of PPARβ,eNOS at protein level and NO content,and increased iNOS,3-nitrotyrosine protein expression and peroxynitrite level.The above effects of HG were reversed by PPARβ agonist GW0742(1 μmol·L-1).Both PPARβ antagonist GSK0660(1 μmol·L-1)and NOS inhibitor L-NAME(10 μmol·L-1)blocked the protective effects of GW0742.Conclusion The down-regulation of PPARβ is involved in the injury of HUVECs induced by high glucose,which may be mediated,at least partly,by the stimulation of nitrative stress.

PPARβ-related signal pathway involves in the effect of polydatin on high glucose-and insulin-induced cardiomyocyte hypertrophy / 中国药理学通报

Aim To investigate the effect of polydatin on cardiomyocyte hypertrophy induced by high glucose (25.5 mmol·L -1 )and insulin (0.1 μmol ·L -1 ) (HGI)and its possible influence on peroxisome prolif-erator-activated receptor-β (PPARβ)/nuclear tran-scription factor-κB (NF-κB)/nitric oxide (NO)signa-ling pathway.Methods The cardiomyocyte hypertro-phy was characterized in rat primary cardiomyocytes by measuring the cell surface area,protein content,and atrial natriuretic factor (ANF)mRNA expression.The mRNA and protein expressions were measured by qRT-PCR and Western blotting,respectively.The activity of NO synthase (NOS)and NO content were measured by reagent kit through ultraviolet spectroscopy.Results HGI significantly induced cardiomyocyte hypertrophy which increased the cell surface area,protein content and ANF mRNA expression (P <0.01 ).Meanwhile, the expressions of PPARβmRNA and protein reduced while the NF-κB p65 and iNOS expressions increased significantly which occurred in parallel with rising NOS activity and NO concentration (P <0.01 ).Polydatin (0.1,1,10 μmol·L -1 )inhibited the cardiomyocyte hypertrophy induced by HGI (P <0.01 ),and re-versed the mRNA and protein expressions of PPARβ, NF-κB p65 and iNOS,and NOS activity,as well as NO content.These effects of polydatin were abolished by GSK0660 (1 μmol·L -1 ),a selective PPARβan-tagonist (P <0.05 ).Conclusion Polydatin resists HGI-induced cardiomyocyte hypertrophy,which may be mediated by PPARβup-regulation,and then NF-κB-iNOS-NO pathway inactivation.

Expression of peroxisome proliferator-activated receptor β/δ in psoriatic epidermal keratinocytes / 中华皮肤科杂志

Objective To measure the expression of peroxisome proliferator-activated receptor β/δ (PPARβ/δ) in epidermal keratinocytes from patients with psoriasis,and to investigate its regulatory factors.Methods Tissue specimens were obtained from both lesional and non-lesional skin of 20 patients with psoriasis as well as from normal skin of 15 human controls.An immunohistochemical method was used to examine the expression of PPARβ/δ in these tissue specimens.Epidermal keratinocytes were isolated from these tissue specimens and subjected to a primary culture.After several passages of subculture,non-lesional psoriatic keratinocytes were stimulated with different concentrations of GW501516 (an agonist of PPARβ/δ,0-100 ng/ml) and Ca2+ (0-3.0 mmol/L).Reverse transcription-PCR and Western blot were performed to measure the mRNA and protein expressions of PPARβ/δ in the primary keratinocytes and stimulated keratinocytes respectively.Results Immunohistochemistry showed that the expression intensity of PPARβ/δ was significantly higher in lesional psoriatic skin than in normal control skin (t =19.28,P ＜ 0.01) and non-lesional psoriatic skin (t =23.26,P ＜ 0.01).Increased mRNA and protein levels of PPARβ/δ were observed in lesional psoriatic keratinocytes as compared to normal control keratinocytes (both P ＜0.01) and non-lesional psoriatic keratinocytes (both P ＜ 0.01).Among these stimulated non-lesional psoriatic keratinocytes,those treated with GW501516 at 10 ng/ml and those with Ca2+ of 1.0 mmol/L showed the strongest expression of PPARβ/δ (both P ＜ 0.01).Conclusions The expression of PPARβ/δ,which is higher in lesional psoriatic skin,can be enhanced by GW501516 and Ca2+ in keratinocytes.

Role of PPARβ in fibroblast response to heat injury.

Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family of ligand-inducible transcription factors. Our previous study has shown that in human umbilical vein endothelial cells PPARβ initiates a protective mechanism that limits the extent of damage due to H2O2-induced injury. Although fibroblasts are one of the main cell types involved in wound repair, the role of PPARβ in the fibroblast response to heat injury has not been investigated. Thus, in this study, we examined possible protective role of PPARβ in fibroblasts from heat injury. We developed a novel dermal fibroblast heat injury model to characterize the mechanisms of the heat injury healing response that involved PPARβ. The specific PPARβ ligand GW0742, a PPARβ activator and a short hairpin RNA (shRNA) plasmid against PPARβ were used to reveal the action mechanism of PPARβ in heat injury-induced fibroblast changes in morphology and increased proliferation. In response to heat injury (52˚C for 30 s), fibroblast activation of PPARß, increased 1.56-fold. Administration of GW0742 significantly induced a protective effect on heat injury-induced fibroblasts by minimizing the structural damage and increasing the cell proliferation response. Likewise, inhinition of PPARß, usingh shRNA exacerbated the damage by inhibiting the de novo synthesis of PPARß. These results indicated that heat injury enhanced PPARß expression and PPARß protected fibroblast structure and proliferation.