PPARα activation alleviates damage to the cytoskeleton during acute myocardial ischemia/reperfusion in rats

4-phenylbutyric acid improves sepsis-induced cardiac dysfunction by modulating amino acid metabolism and lipid metabolism via Comt/Ptgs2/Ppara

INTRODUCTION

Cardiac dysfunction after sepsis the most common and severe sepsis-related organ failure. The severity of cardiac damage in sepsis patients was positively associated to mortality. It is important to look for drugs targeting sepsis-induced cardiac damage. Our previous studies found that 4-phenylbutyric acid (PBA) was beneficial to septic shock by improving cardiovascular function and survival, while the specific mechanism is unclear.

OBJECTIVES

We aimed to explore the specific mechanism and PBA for protecting cardiac function in sepsis.

METHODS

The cecal ligation and puncture-induced septic shock models were used to observe the therapeutic effects of PBA on myocardial contractility and the serum levels of cardiac troponin-T. The mechanisms of PBA against sepsis were explored by metabolomics and network pharmacology.

RESULTS

The results showed that PBA alleviated the sepsis-induced cardiac damage. The metabolomics results showed that there were 28 metabolites involving in the therapeutic effects of PBA against sepsis. According to network pharmacology, 11 hub genes were found that were involved in lipid metabolism and amino acid transport following PBA treatment. The further integrated analysis focused on 7 key targets, including Comt, Slc6a4, Maoa, Ppara, Pparg, Ptgs2 and Trpv1, as well as their core metabolites and pathways. In an in vitro assay, PBA effectively inhibited sepsis-induced reductions in Comt, Ptgs2 and Ppara after sepsis.

CONCLUSIONS

PBA protects sepsis-induced cardiac injury by targeting Comt/Ptgs2/Ppara, which regulates amino acid metabolism and lipid metabolism. The study reveals the complicated mechanisms of PBA against sepsis.

An insight to treat cardiovascular diseases through phytochemicals targeting PPAR-α

Peroxisome proliferator-activated receptor-α (PPAR-α) belonging to the nuclear hormone receptor superfamily is a promising target for CVDs which mechanistically improves the production of high-density lipid as well as inhibit vascular smooth muscle cell proliferation. PPAR-α mainly interferes with adenosine monophosphate-activated protein kinase, transforming growth factor-β-activated kinase, and nuclear factor-κB pathways to protect against cardiac complications. Natural products/extracts could serve as a potential therapeutic strategy in CVDs for targeting PPAR-α with broad safety margins. In recent years, the understanding of naturally derived PPAR-α agonists has considerably improved; however, the information is scattered. In vitro and in vivo studies on acacetin, apigenin, arjunolic acid, astaxanthin, berberine, resveratrol, vaticanol C, hispidulin, ginsenoside Rb3, and genistein showed significant effects in CVDs complications by targeting PPAR-α. With the aim of demonstrating the tremendous chemical variety of natural products targeting PPAR-α in CVDs, this review provides insight into various natural products that can work to prevent CVDs by targeting the PPAR-α receptor along with their detailed mechanism.

Peroxisome Proliferator-Activated Receptor α Activation Protects Retinal Ganglion Cells in Ischemia-Reperfusion Retinas

Background and Objective: Retinal ischemia-reperfusion (IR) leads to massive loss of retinal ganglion cells (RGC) and characterizes several blind-causing ophthalmic diseases. However, the mechanism related to retinal IR is controversial, and a drug that could prevent the RGC loss caused by IR is still lacking. This study aimed to investigate the role of endogenous retinal peroxisome proliferator-activated receptor (PPAR)α and the therapeutic effect of its agonist, fenofibric acid (FA), in IR-related retinopathy. Materials and Methods: Fenofibric acid treatment was applied to the Sprague-Dawley rats with IR and retinal cell line 28 cells with oxygen-glucose deprivation (OGD) (an in vitro model of IR). Western blotting, real-time PCR, and immunofluorescence were used to examine the expression levels of PPARα, glial fibrillary acidic protein (GFAP), and cyclooxygenase-2 (COX2). Hematoxylin and eosin (HE) staining, propidium iodide (PI) staining, retrograde tracing, and flash visual-evoked potential (FVEP) were applied to assess RGC injury and visual function. Results: Retinal IR down-regulated PPARα expression in vitro and in vivo. Peroxisome proliferator-activated receptor α activation by FA promoted survival of RGCs, mitigated thinning of the ganglion cell complex, and decreased the latency of positive waves of FVEPs after IR injury. Further, FA treatment enhanced the expression of endogenous PPARα and suppressed the expression of GFAP and COX2 significantly. Conclusion: Peroxisome proliferator-activated receptor α activation by FA is protective against RGC loss in retinal IR condition, which may occur by restoring PPARα expression, inhibiting activation of glial cells, and suppressing retinal inflammation. All these findings indicate the translational potential of FA in treating IR-related retinopathy.

Activation of PPARα by Fenofibrate Attenuates the Effect of Local Heart High Dose Irradiation on the Mouse Cardiac Proteome

Radiation-induced cardiovascular disease is associated with metabolic remodeling in the heart, mainly due to the inactivation of the transcription factor peroxisome proliferator-activated receptor alpha (PPARα), thereby inhibiting lipid metabolic enzymes. The objective of the present study was to investigate the potential protective effect of fenofibrate, a known agonist of PPARα on radiation-induced cardiac toxicity. To this end, we compared, for the first time, the cardiac proteome of fenofibrate- and placebo-treated mice 20 weeks after local heart irradiation (16 Gy) using label-free proteomics. The observations were further validated using immunoblotting, enzyme activity assays, and ELISA. The analysis showed that fenofibrate restored signalling pathways that were negatively affected by irradiation, including lipid metabolism, mitochondrial respiratory chain, redox response, tissue homeostasis, endothelial NO signalling and the inflammatory status. The results presented here indicate that PPARα activation by fenofibrate attenuates the cardiac proteome alterations induced by irradiation. These findings suggest a potential benefit of fenofibrate administration in the prevention of cardiovascular diseases, following radiation exposure.

Deficiency of peroxisome proliferator-activated receptor α attenuates apoptosis and promotes migration of vascular smooth muscle cells

Peroxisome proliferator-activated receptor (PPAR) α is widely expressed in the vasculature and has pleiotropic and lipid-lowering independent effects, but its role in the growth and function of vascular smooth muscle cells (VSMCs) during vascular pathophysiology is still unclear. Herein, VSMC-specific PPARα-deficient mice (Ppara ^ΔSMC) were generated by Cre-LoxP site-specific recombinase technology and VSMCs were isolated from mice aorta. PPARα deficiency attenuated VSMC apoptosis induced by angiotensin (Ang) II and hydrogen peroxide, and increased the migration of Ang II-challenged cells.

Network Pharmacology Prediction and Pharmacological Verification Mechanism of Yeju Jiangya Decoction on Hypertension

Background

Yeju Jiangya decoction (CIF) is an herbal formula from traditional Chinese medicine (TCM) for the treatment of hypertension.

Materials and Methods

Based on the analysis of network pharmacology, combined with in animal experiments, the network pharmacology was used to explore the potential proteins and mechanisms of CIF against hypertension. The bioactive compounds of CIF were screened by using the platform, and the targets of hypertension and CIF were collected. Then, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction network (PPI) core targets were carried out, and the useful proteins were found by molecular docking technology. Finally, we used N-nitro-L-arginine (L-NNA) induced hypertension model rats to confirm the effect and mechanism of CIF on hypertension.

Results

14 bioactive compounds of CIF passed the virtual screening criteria, and 178 overlapping targets were identified as core targets of CIF against hypertension. The CIF-related target network with 178 nodes and 344 edges is constructed. The topological results show that quercetin and luteolin are the key components in the network. The key targets NOS3 (nitric oxide synthase 3) and NOS2 (nitric oxide synthase 2) were screened by the protein-protein interaction network. The analysis of target protein pathway enrichment showed that the accumulation pathway is related to the vascular structure of CIF regulation of hypertension. Further verification based on molecular docking results showed that NOS3 had the good binding ability with quercetin and luteolin. On the other hand, NOS3 has an important relationship with the composition of blood vessels. Furthermore, the animal experiment indicated that after the L-NNA-induced hypertension rat model was established, CIF intervention was given by gavage for 3 weeks, and it can decrease serum concentrations of endothelin-1 (ET-1) and thromboxane B2 (TXB₂), increase the expression of nitric oxide (NO) and prostacyclin 2 (PGI₂), and improve renal, cardiac, and aortic lesions. At the same time, it can reduce blood pressure and shorten vertigo time. Western blot (WB) and immunohistochemistry (IHC) analyses indicated that CIF may downregulate the expression of NOS3, guanylyl cyclase-alpha 1 (GC-α1), guanylyl cyclase-alpha 2 (GC-α2), and protein kinase CGMP-dependent 1 (PRKG1). These results suggest that CIF may play an antihypertensive role by inhibiting the activation of the NOS3/PRKG1 pathway.

Conclusions

The results of this study indicate that CIF has the ability to improve target organs, protect endothelial function, and reduce blood pressure and that CIF might be a potential therapeutic drug for the prevention of hypertension. It provides new insight into hypertension and the potential biological basis and mechanism for CIF clinical research.

The critical role of PPARα in the binary switch between life and death induced by endoplasmic reticulum stress

Endoplasmic reticulum stress (ER stress) just like a double-edged sword depending on different conditions in the development of multiple hepatic diseases. But the molecular mechanisms of functional conversion during ER stress have not been fully elucidated. In this study, we aim to illustrate the role of PPARα and the subtle mechanism in the functional conversion of ER stress. Tunicamycin (TM) and thapsigargin (TG), as ER stress inducers, were used to induce ER stress in AML12 cells. During the ER stress, qRT-PCR and immunoblotting was used to measure the expression levels of GRP78 and CHOP which show a gradually increasing trend, while PPARα and autophagy was significantly activated in the early stage but was inhibited in the late stage. Moreover, PPARα inhibition by siRNA promoted cell injury in the mild-ER stress and PPARα activation by WY-14643 reduced cell apoptosis in the serious ER stress. In the mild-ER stress with PPARα knocked down, activation of autophagy by rapamycin significantly improved cell survival, in the serious ER stress with PPARα activation, inhibition of autophagy by 3-MA aggravate cell injury. In addition, in the mild-ER stress with PPARα knocked down, CHOP knocked down by siRNA reduced cell apoptosis, in the serious ER stress activated PPARα, CHOP over-expression mediated by lentiviral vector contributed to serious cell injury. Furthermore, C57BL/6 mice was used to induce ER stress with TM intraperitoneal injection, PPARα and autophagy was upregulated in the mild-ER stress while downregulated in the serious ER stress, measured by qRT-PCR and immunoblotting, further confirmed the finding in vitro. Our results firstly demonstrated that PPARα is a key molecule in the functional conversion of ER stress: protective effects in the mild ER stress was mediated by PPARα-autophagy pathway and destructive effects in the serious ER stress was mediated by PPARα-CHOP pathway.

Garlic antagonizes skeletal muscle ischemia reperfusion injury through regulating inflammation, apoptosis and desmin expression in adult male rats

BACKGROUND

Skeletal muscle injuries with subsequent bleeding is common cause of death on both sports and battle grounds. Application and removal of tourniquet is fast intervention to control hemorrhage resulting ischemia reperfusion (IR) injury. The effect of IR in skeletal muscle is far more severe compared to other body tissues because of the devastating systemic complication. Garlic has beneficial effects in IR of various organs. However, using garlic in IR of skeletal muscle is deficient Goals: To investigate the possible protective effect of garlic in rat model of hind limb IR and its possible mechanisms of action.

METHODS

Fifty adult male rats divided into five groups; C: control, IR: ischemia/reperfusion group subjected to 2 hours ischemia followed by 2 hours reperfusion (2/2 hr IR) and three garlic treated groups; G1+IR: 24 hr before I/R, G2+IR: 30 min before IR and G3+IR: immediately before reperfusion. We measured wet to dry weight ratio (W/D) of gastrocnemius muscle, serum creatine kinase (CK), Interleukin 1β (IL-1β), Interleukin-10 (IL-10), gastrocnemius caspase-3 and desmin expression and histopathological damage score.

RESULTS

Garlic treatment caused significant decrease in W/D, serum CK, IL-1β, caspase-3 expression and significant increase in IL-10 as well as desmin expression when compared to IR group. Garlic ameliorated IR-induced histopathological damage and significantly reduced the apoptosis score. Better results obtained with earlier administration before IR.

CONCLUSION

Garlic protected against IR-induced skeletal muscle damage through reducing inflammation, apoptosis score and elevating desmin expression. We recommend the earlier use of garlic as prophylactic natural medicine in skeletal muscle IR.

Platelet Microparticles: A Tool to Predict Infarction Area in Rats

Background: Whether there is a quantitative correlation between platelet microparticles (PMPs)/calpain and infarction area is still unclear. Whether present antiplatelet agents can improve myocardial infarction by influencing PMPs need to be revealed. The object of our study was to answer those questions. Methods: Male Wistar rats were used for all studies. All rats were randomly divided into five groups: sham-operated group, myocardial infarction group (blank control group), aspirin intervention group, aspirin combined with clopidogrel intervention group, and aspirin combined with ticagrelor intervention group. Venous blood and hearts were collected at day 7 following MI. ELISA was applied to detect PMPs level. Infarction size was determined by TTC staining method. The comparisons of multiple means were tested with analysis of variance. And the two-two comparisons among the means were done by Student-Newman-Keuls and LSD method. Results: PMPs level and infarction area did not differ between aspirin combined with clopidogrel intervention group and aspirin combined with ticagrelor intervention group. However, significant differences were detected between any two other groups. PMPs were decreased more in dual antiplatelet intervention group. Pearson correlation analysis showed a strong correlation between PMPs and infarction area (r = 0.90) as well as calpain 10 and infarction area (r = 0.84). We created a regression model: y = 4.61 + 0.28*x (y: infarction area, x: PMPs) to assess myocardial infarction area by PMPs level. Conclusions: Antiplatelet agents may decrease infarction areas by modifying PMPs. There was a strong correlation between PMPs and infarction area. Therefore, PMPs could be used as a tool to assess infarction area.