Soluble epoxide hydrolase inhibitor, TPPU, attenuates progression of atherosclerotic lesions and vascular smooth muscle cell phenotypic switching

Restoration of ARA metabolic disorders in vascular smooth muscle cells alleviates intimal hyperplasia

Intimal hyperplasia (IH) is an innegligible issue for patients undergoing interventional therapy. The proliferation and migration of vascular smooth muscle cells (VSMCs) induced by platelet-derived growth factor-BB (PDGF-BB) are critical events in the development of IH. While the exact mechanism and effective target for IH needs further investigation. Metabolic disorders of arachidonic acid (ARA) are involved in the occurrence and progression of various diseases. In this study, we found that the expressions of soluble epoxide hydrolase (sEH) and cyclooxygenase-2 (COX-2) were significantly increased in the VSMCs during balloon injury-induced IH. Then, we employed a COX-2/sEH dual inhibitor PTUPB to increase the concentration of epoxyeicosatrienoic acids (EETs) while prevent the release of pro-inflammatory prostaglandins. Results showed that PTUPB treatment significantly reduced neointimal thickening induced by balloon injury in rats in vivo and inhibited PDGF-BB-induced proliferation and migration of VSMCs in vitro. Our results showed that PTUPB may reverse the phenotypic transition of VSMCs by inhibiting Pttg1 expression. In conclusion, we found that the dysfunction of ARA metabolism in VSMCs contributes to IH, and the COX-2/sEH dual inhibitor PTUPB attenuates IH progression by reversing the phenotypic switch in VSMC through the Sirt1/Pttg1 pathway.

Role of soluble epoxide hydrolase in the abnormal activation of fibroblast-like synoviocytes from patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by enigmatic pathogenesis. Polyunsaturated fatty acids (PUFAs) are implicated in RA's development and progression, yet their exact mechanisms of influence are not fully understood. Soluble epoxide hydrolase (sEH) is an enzyme that metabolizes anti-inflammatory epoxy fatty acids (EpFAs), derivatives of PUFAs. In this study, we report elevated sEH expression in the joints of CIA (collagen-induced arthritis) rats, concomitant with diminished levels of two significant EpFAs. Additionally, increased sEH expression was detected in both the synovium of CIA rats and in the synovium and fibroblast-like synoviocytes (FLS) of RA patients. The sEH inhibitor TPPU attenuated the migration and invasion capabilities of FLS derived from RA patients and to reduce the secretion of inflammatory factors by these cells. Our findings indicate a pivotal role for sEH in RA pathogenesis and suggest that sEH inhibitors offer a promising new therapeutic strategy for managing RA.

Chrysanthemum coronarium L. Extract Attenuates Homocysteine-Induced Vascular Inflammation in Vascular Smooth Muscle Cells

Hyperhomocysteinemia is a main risk factor for phenotypic modulation of vascular smooth muscle cells (VSMCs) and atherosclerosis. Phenotypic switching and proliferation of VSMCs are related to the progression of vascular inflammation. Chrysanthemum coronarium L. is a leafy vegetable with various biological functions, such as antioxidative, anti-inflammatory, and antiproliferative effects. In this study, we aimed to identify the mechanisms underlying the therapeutic and preventive effects of C. coronarium L. extract (CC) in regulating homocysteine (Hcy)-induced vascular inflammation in human aortic VSMCs. CC did not exhibit cytotoxicity and inhibited Hcy-stimulated VSMC proliferation and migration. In addition, CC promoted Hcy-induced expression of VSMC contractile phenotype proteins, including alpha-smooth muscle actin, calponin, and smooth muscle 22α. CC also decreased Hcy-induced accumulation of reactive oxygen species and expression of inflammatory markers nicotinamide adenine dinucleotide phosphate oxidase-4 and soluble epoxide hydrolase. These results showed that CC attenuates Hcy-induced inflammatory responses, highlighting its potential as a therapeutic or preventive target for Hcy-induced vascular inflammation.

Renoprotective Effect of Chrysanthemum coronarium L. Extract on Adenine-Induced Chronic Kidney Disease in Mice

Chronic kidney disease (CKD) gradually leads to loss of renal function and is associated with inflammation and fibrosis. Chrysanthemum coronarium L., a leafy vegetable, possesses various beneficial properties, including anti-oxidative, anti-inflammatory, and antiproliferative effects. In this study, we investigated the renoprotective effect of Chrysanthemum coronarium L. extract (CC) on adenine (AD)-induced CKD in mice. CKD was induced by feeding mice with an AD diet (0.25% w/w) for 4 weeks. Changes in renal function, histopathology, inflammation, and renal interstitial fibrosis were analyzed. The adenine-fed mice were characterized by increased blood urea nitrogen, serum creatinine, and histological changes, including inflammation and fibrosis; however, these changes were significantly restored by treatment with CC. Additionally, CC inhibited the expression of the inflammatory markers, monocyte chemoattractant protein-1, interleukins-6 and -1β, intercellular adhesion molecule-1, and cyclooxygenase 2. Moreover, CC suppressed the expression of the fibrotic markers, type IV collagen, and fibronectin. Furthermore, CC attenuated the expression of profibrotic genes (tumor growth factor-β and α-smooth muscle actin) in AD-induced renal injury mice. Thus, our results suggest that CC has the potential to attenuate AD-induced renal injury and might offer a new option as a renoprotective agent or functional food supplement to manage CKD.

Hepatocyte-specific disruption of soluble epoxide hydrolase attenuates abdominal aortic aneurysm formation: novel role of the liver in aneurysm pathogenesis

Introduction

Inflammation is a key pathogenic feature of abdominal aortic aneurysm (AAA). Soluble epoxide hydrolase (sEH) is a pro-inflammatory enzyme that converts cytochrome P450-derived epoxides of fatty acids to the corresponding diols, and pharmacological inhibition of sEH prevented AAA formation. Both cytochrome P450 enzymes and sEH are highly expressed in the liver. Here, we investigated the role of hepatic sEH in AAA using a selective pharmacological inhibitor of sEH and hepatocyte-specific Ephx2 (which encodes sEH gene) knockout (KO) mice in two models of AAA [angiotensin II (AngII) infusion and calcium chloride (CaCl 2 ) application].

Methods and results

sEH expression and activity were strikingly higher in mouse liver compared with aorta and further increased the context of AAA, in conjunction with elevated expression of the transcription factor Sp1 and the epigenetic regulator Jarid1b, which have been reported to positively regulate sEH expression. Pharmacological sEH inhibition, or liver-specific sEH disruption, achieved by crossing sEH floxed mice with albumin-cre mice, prevented AAA formation in both models, concomitant with reduced expression of hepatic sEH as well as complement factor 3 (C3) and serum amyloid A (SAA), liver-derived factors linked to AAA formation. Moreover, sEH antagonism markedly reduced C3 and SAA protein accumulation in the aortic wall. Co-incubation of liver ex vivo with aneurysm-prone aorta resulted in induction of sEH in the liver, concomitant with upregulation of Sp1, Jarid1b, C3 and SAA gene expression, suggesting that the aneurysm-prone aorta secretes factors that activate sEH and downstream inflammatory signaling in the liver. Using an unbiased proteomic approach, we identified a number of dysregulated proteins [ e.g., plastin-2, galectin-3 (gal-3), cathepsin S] released by aneurysm-prone aorta as potential candidate mediators of hepatic sEH induction.

Conclusion

We provide the first direct evidence of the liver's role in orchestrating AAA via the enzyme sEH. These findings not only provide novel insight into AAA pathogenesis, but they have potentially important implications with regard to developing effective medical therapies for AAA.

Proanthocyanidins may be potential therapeutic agents for the treatment of carotid atherosclerosis: A review

Atherosclerotic cerebrovascular disease is one of the major causes of death in China, with associated serious risk of disability and burden on society and families. Therefore, the development of active and effective therapeutic drugs for this disease is of great significance. Proanthocyanidins are a class of naturally occurring active substances, rich in hydroxyl groups and from a wide range of sources. Studies have suggested that they have a strong potential for anti-atherosclerosis activity. In this paper, we review published evidence regarding anti-atherosclerotic effects of proanthocyanidins in different atherosclerotic research models.

Ureas derived from camphor and fenchone reveal enantiomeric preference of human soluble epoxide hydrolase

The soluble epoxide hydrolase (sEH) is a potential target to treat cardiovascular, renal and neuronal diseases. A series of sEH inhibitors containing naturally occurring lipophilic groups (originating from camphor and fenchone) were developed. Inhibitory potency ranging from 0.7 nM to 6.47 μM was obtained. It was discovered that ureas derived from L-camphor were more active against sEH (2.3-fold average) than the corresponding analogues derived from D-camphor indicating enantiomeric preference of sEH. Ureas derived from fenchone possess lower activity against sEH (ca. 80-fold on average) than their camphor-derived analogs due to the specific structure of the lipophilic fragment and show less enantiomeric preference (1.75-fold on average). Moreover, fenchone-derived ureas show no consistency in enantiomeric preference. Endo/exo-form of compound L-3a derived from L-camphor is 4-fold more potent than the corresponding analogue prepared from D-camphor (IC50 = 0.7 nM vs. 2.8 nM) making it the most promising sEH inhibitor among the tested series.