The Regulation Of PI3K/ERK1/2/NF-?B/PPAR?/SCAD Signal Pathway To Cardiac Fibrosis

Objective:Short-chain acyl-Co A dehydrogenase(SCAD)is a rate-limiting enzyme for ? oxidation of mitochondrial fatty acids.Previous studies have shown that PPAR? mediates SCAD that the regulation of cardiac fibrosis.The purpose of this article is to study the regulation of PI3K/ERK1/2/NF-?B/PPAR?/SCAD signaling pathway on cardiac fibrosis,and to clarify a new mechanism of SCAD to regulate cardiac fibrosis.Method:1.Animal model of cardiac fibrosis was induced by spontaneously hypertensive rat(SHR).And swimming exercise intervention was performed.Western blot was used to detect the change of PI3 K p110?,PI3 K p110?,p-ERK1/2,p-I?B? and p-p65 protein expressions.Western blot and Real-time PCR were used to detect SCAD,PPAR? and fibrosis indicators ?-SMA,Collagen I and Collagen III protein and m RNA levels.Simultaneously,SCAD enzyme activity,ATP content and free fatty acid content were also detected.2.The primary cardiac fibroblasts(CFs)treated with angiotensin(Ang II)were used as the model of cardiac fibrosis in vitro.Western blot was used to detect the change of PI3 K p110?,PI3 K p110?,p-ERK1/2,p-I?B? and p-p65 protein expressions.Western blot and Real-time PCR were used to detect SCAD,PPAR? and fibrosis indicators ?-SMA,Collagen I and Collagen III protein and m RNA levels.At the same time,SCAD enzyme activity,ATP content and free fatty acid content were also detected.3.Cells were respectively pretreated with NF-?B p65 activator LPS,inhibitor Maslinic acid and PPAR? activator fenofibrate for 30 min,then stimulated with Ang II.Western blot was used to detect the protein expressions of p-p65.Western blot and Real-time PCR were used to detect the protein and m RNA levels of SCAD,PPAR? and fibrosis indicators ?-SMA,Collagen I and Collagen III.SCAD enzyme activity,ATP and free fatty acid content,hydroxyproline content,and Cell proliferation rate were measured.4.Cells were respectively pretreated with ERK1/2 activator EGF,inhibitor PD98059 and NF-?B inhibitor Maslinic acid for 30 min,then stimulated with Ang II.Western blot was used to detect the protein expression of p-ERK1/2,p-I?B? and p-p65.Western blot and Real-time PCR were used to detect the m RNA and protein levels of SCAD,PPAR?and fibrosis indicators ?-SMA,Collagen I and Collagen III.SCAD enzyme activity,ATP content,free fatty acid content and hydroxyproline content,and Cell proliferation rate were measured.5.Cells were respectively pretreated with PI3 K p110? inhibitor A66 and PI3K p110? inhibitor AS605240 for 30 min,then stimulated with Ang II.Western blot was used to detect the protein expression of PI3 K p110?,PI3 K p110?,p-ERK1/2,p-I?B? and p-p65.Western blot and Real-time PCR were used to detect the change of SCAD,PPAR? and fibrosis indicators ?-SMA,Collagen I and Collagen III protein and m RNA levels.SCAD enzyme activity changes,ATP content,free fatty acid content,hydroxyproline content,and Cell proliferation rate were detected.Result:1.SHR manifested as cardiac fibrosis at 20 weeks of age.Compared with wistar rats,the protein expression of PI3 K p110? was significantly decreased;the protein expression of PI3 K p110?,p-ERK1/2,p-I?B?,p-p65 were significantly increased.At the same time,SCAD expression and enzyme activity were significantly decreased,fatty acid oxidation capacity is weakened.The expression of fibrosis indicators?-SMA,Collagen I and Collagen III were significantly increased.After 8weeks of swimming training in SHR,PI3 K p110? expression was significantly increased,PI3 K p110?,p-ERK1/2,p-I?B?,and p-p65 proteins were significantly decreased.In the SHR swimming group, SCAD enzyme activity increased,mitochondrial fatty acid ? oxidation ability increased,cardiac function was significantly improved,and cardiac fibrosis was significantly improved.2.Compared with the control group,the proliferation rate of CFs and the expression of fibrosis indicators ?-SMA,Collagen I,and Collagen III were significantly increased after Ang II stimulated CFs,indicating that Ang II stimulated CFs to successfully establish a model of cardiac fibrosis in vitro.The protein expression of PI3 K p110?,PPAR?and SCAD was significantly decreased;the protein expression of PI3 K p110?,p-ERK1/2,p-I?B? and p-p65 were significantly increased.SCAD enzyme activity was significantly decreased,and mitochondrial fatty acid? oxidation capacity was weakened,and the change trend was consistent with SHR cardiac fibrosis.3.Compared with the control group,CFs proliferation rate and collagen molecule m RNA and protein expression levels were significantly increased,p-p65 expression was significantly up-regulated.SCAD expression was significantly decreased,and CFs energy metabolism disorder was obvious.While Maslinic acid group was able to down-regulate fibrosis factor levels and p-p65 expression levels.Then cause SCAD expression was increased,thereby enhancing fatty acid ?oxidation ability.Compared with Ang II group,there was no significant difference in Ang II+LPS group.The protein expression of p-p65 in Ang II+Maslinic acid group was significantly down-regulated,CAD expression and enzyme activity were significantly increased,and fatty acid ? oxidation levels were significantly increased,which resulted in increased ATP production and free fatty acids utilization increased then decreased free fatty acids content;and the proliferation rate of CFs and the expression levels of fibrosis indicators ?-SMA,Collagen I,and Collagen III were significantly reduced.Compared with Ang II group,the expression of p-p65 was unchanged in Ang II+LPS+Feno group,PPAR and SCAD expressions were significantly increased,energy metabolism disorders were significantly improved,CFs proliferation rate and collagen expression levels were significantly reduced.4.Compared with the control group,while in the EGF group,the CFs proliferation rate and the protein expression level of cell fibrosis factor were significantly increased.The change of p-ERK1/2,p-I?B?,and p-p65 proteins were significantly increased,SCAD expression and enzyme activity were significantly decreased,and fatty acid ? oxidation levels were significantly reduced,impaired energy metabolism was obvious.PD98059 group can significantly reduce the expression of CFs fibrosis factors and p-ERK1/2,p-I?B?,p-p65 protein levels,SCAD expression is significantly up-regulated,inhibit CFs proliferation and promote energy metabolism.Compared with Ang II group,there was no significant difference in Ang II+EGF.In PD98059 group,the change of p-ERK1/2,p-I?B? and p-p65 protein levels were decreased,SCAD expression and enzyme activity were significantly increased,ATP content was increased,and free fatty acid utilization was increased then reduces its content,meanwhile the proliferation rate of CFs was significantly reduced,and the expression of fibrosis index was significantly decreased.Compared with the Ang II group,the expressions of p-ERK1/2 and p-I?B? in the Ang II+EGF+Maslinic acid group were unchanged,p-p65 expression was decreased,which caused SCAD expression to be increased and CFs energy metabolism disorders were significantly improved.5.Compared with the control group,the expression of PI3 K p110?in the A66 group was significantly down-regulated,the expression of PI3 K p110? was unchanged,the expressions of p-ERK1/2,p-I?B?,and p-p65 were significantly up-regulated,and the expressions of SCAD were significantly down-regulated.A66-treated CFs inhibited PI3 K p110?After expression,the proliferation rate of CFs and the expression level of fibrosis indicators were increased.Compared with the Ang II group,the expression of PI3 K p110? in the Ang II+AS605240 group was significantly down-regulated,the expression of PI3 K p110? was unchanged,the expressions of p-ERK1/2,p-I?B? and p-p65 proteins were significantly down-regulated,and the expression of SCAD was significantly up-regulated.The proliferation rate of CFs was obvious increased.After AS605240 treatment of CFs,by inhibiting the expression of PI3 K p110?,and then regulating downstream targets,thereby improving the myocardial energy metabolism disorder caused by Ang II stimulation.Conclusion:PI3K p110?/? mediates ERK1/2 and NF-?B,thereby regulating the role of PPAR? and SCAD in cardiac fibrosis.The PI3K/ERK1/2/NF-?B/PPAR?/SCAD signaling pathway plays an important role in cardiac fibrosis.