IcarisideII improves left ventricular remodeling in spontaneously hypertensive rats by inhibiting the ASK1-JNK/p38 signaling pathway

Cancer-Related Therapeutic Potential of Epimedium and Its Extracts

Epimedium is a Chinese herb known as "yin and yang fire," first mentioned in the Compendium of Materia Medica. Many of the proprietary Chinese medicines used in clinical practice contain Epimedium as an ingredient, and its main active constituents include icariin, icaritin, and icariside II, among others. In addition to its traditional use in treating fatigue and sexual problems, modern research has confirmed that the main bioactive compounds in Epimedium have pharmacological effects such as antidepressant, antibacterial, antiviral, antioxidant, and anti-inflammatory properties, as well as inhibiting bone destruction, promoting bone growth, improving immune regulation and protecting the cardio-cerebral vascular system. With the continuous development of extraction and purification techniques, the development and use of bioactive compounds in Epimedium have significantly progressed, and the anticancer effect has received widespread attention. Since natural herbs have few side effects on the human body and do not easily develop drug resistance, they have long been the direction of research in cancer treatment. This review summarizes the latest research on the anticancer effects of Epimedium and its extracts, describes the bioactive compounds, pharmacological efficacy, and antitumor mechanism of Epimedium, and gives a new view on the administration and development of Epimedium.

High hydrostatic pressure participates in atrial fibrosis through the p300/p53/Smad3 pathway

As an independent risk factor of atrial fibrillation (AF), hypertension (HTN) can induce atrial fibrosis through cyclic stretch and hydrostatic pressure. The mechanism by which high hydrostatic pressure promotes atrial fibrosis is unclear yet. p300 and p53/Smad3 play important roles in the process of atrial fibrosis. This study investigated whether high hydrostatic pressure promotes atrial fibrosis by activating the p300/p53/Smad3 pathway. Biochemical experiments were used to study the expression of p300/p53/Smad3 pathway in left atrial appendage (LAA) tissues of patients with sinus rhythm (SR), AF, AF + HTN, and C57/BL6 mice, hypertensive C57/BL6 mice and atrial fibroblasts of mice. To investigate the roles of p300 and p53 in the process of atrial fibrosis, p300 and p53 in mice atrial fibroblasts were knocked in or knocked down, respectively. The expression of p300/p53/Smad3 and fibrotic factors was higher in patients with AF and AF + HTN than those with SR only. The expressions of p300/p53/Smad3 and fibrotic factors increased in hypertensive mice. Curcumin (Cur) and knocking down of p300 reversed the expressions of these factors. 40 mmHg hydrostatic pressure/overexpression of p300 upregulated the expressions of p300/p53/Smad3 and fibrotic factors in mice LAA fibroblasts. While Cur or knocking down p300 reversed these changes. Knocking down/overexpression of p53, the expressions of p53/Smad3 and fibrotic factors also decreased/increased, correspondingly. High hydrostatic pressure promotes atrial fibrosis by activating the p300/p53/Smad3 pathway, which further increases the susceptibility to AF.

Resveratrol alleviates heat-stress-induced impairment of the jejunal mucosa through TLR4/MAPK signaling pathway in black-boned chicken

Heat stress in chickens caused by high temperatures in summer is a serious issue faced by the poultry industry globally, which reduces product quality. The aim of this study is to investigate the role of resveratrol in alleviating heat stress injury and inflammatory response of jejunal mucosa in black-boned chickens through TLR4/MAPK signaling pathway. In total, 240 black-boned chickens (28-day old) were randomly divided into 4 treatment groups as follows. The normal temperature (NT) and normal temperature with resveratrol (NT+Res) groups received a basal diet without and with 400 mg/kg resveratrol, respectively, and treated at 24℃ ± 2℃, 24 h/d. The high temperature (HT) and high temperature with resveratrol (HT+Res) groups received basal diet without and with 400 mg/kg resveratrol, respectively, and treated at 37℃ ± 2℃ for 8 h/d and 24°C ± 2°C for the rest of the time for 12 d. The results revealed the heat-stress responses impaired the villous structure of the jejunum, causing a rough and uneven surface of the jejunal villus, and local intestinal villi were even more prone to rupture. However, resveratrol significantly improved the morphology and structure of jejunal mucosa under heat stress. Heat stress increased the mRNA levels of toll-like receptor 4 (TLR4), c-Jun, c-fos, caspase-3, and p38 (P < 0.05), reduced mRNA level of Bcl-2, and reduced the expression of tight junction proteins Occludin, ZO-1, and Claudin1 (P < 0.05) in the jejunal mucosa. However, resveratrol inhibited the TLR4/ mitogen-activated protein kinase (MAPK) signaling pathway via downregulating TLR4, c-Jun, p38, and caspase-3 (P < 0.05); upregulating Bcl-2 (P < 0.05); decreasing the protein levels of MKK3, p53, and myeloid differentiation factor 88 (MYD88); and increasing the protein levels of Occludin, ZO-1, and Claudin1. In addition, it reduced the levels of JNK and p38 proteins (P < 0.05) and inflammatory factors like tumor necrosis factor-α (TNF-α) in the jejunal mucosa of black-boned chickens under heat stress. In conclusion, resveratrol may play a regulatory role in heat-stress-induced damage and inflammatory response in the intestinal mucosa of black-boned chickens under heat stress.

Natural compounds targeting mitochondrial dysfunction: emerging therapeutics for target organ damage in hypertension

Hypertension generally causes target organ damage (TOD) in the heart, brain, kidney, and blood vessels. This can result in atherosclerosis, plaque formation, cardiovascular and cerebrovascular events, and renal failure. Recent studies have indicated that mitochondrial dysfunction is crucial in hypertensive target organ damage. Consequently, mitochondria-targeted therapies attract increasing attention. Natural compounds are valuable resources for drug discovery and development. Many studies have demonstrated that natural compounds can ameliorate mitochondrial dysfunction in hypertensive target organ damage. This review examines the contribution of mitochondrial dysfunction to the development of target organ damage in hypertension. Moreover, it summarizes therapeutic strategies based on natural compounds that target mitochondrial dysfunction, which may be beneficial for preventing and treating hypertensive target organ damage.

Hyperoside alleviates doxorubicin-induced myocardial cells apoptosis by inhibiting the apoptosis signal-regulating kinase 1/p38 pathway

Background

Cardiotoxicity is a side effect of the anthracycline broad-spectrum anti-tumor agent, doxorubicin (DOX). Hyperoside, a flavonoid glycoside extracted from many herbs, has anti-apoptotic and anticancer properties. However, its impact on the alleviation of DOX-induced apoptosis in cardiomyocytes remains elusive.

Methods

The HL-1 cell line was treated with 100 µ M hyperoside for 1 h prior to treatment with 100 µ M hyperoside and 1 µ M DOX for 24 h. The cell counting kit-8 (CCK-8) assay was used to detect cell viability; DCFH-DA fluorescent probe was used to detect (reactive oxygen species) ROS; biochemical methods were used to detect the activity of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA); the degree of apoptosis following DOX insult was assessed using immunofluorescence staining and terminal deoxynucleotidyl transferase mediated deoxy uridine triphosphate nick end labeling (TUNEL) assay; the change in protein expression of apoptosis signal-regulating kinase 1 (ASK1), p38, and apoptosis markers was determined using western blot.

Results

Hyperoside ameliorated DOX-induced oxidative stress in HL-1 cells, up-regulated GSH, SOD and CAT activity, reduced ROS production and inhibited MDA overproduction. Moreover, in addition to promoting HL-1 cell apoptosis, DOX administration also increased B-cell lymphoma (Bcl)-2-associated X-protein and cleaved caspase-3 protein levels and decreased Bcl-2 protein level. Hyperoside therapy, however, significantly reversed the impact of DOX on the cardiomyocytes. Mechanically, DOX treatment increased the phosphorylation of the ASK1/p38 axis whereas hyperoside treatment attenuated those changes. In a further step, hyperoside synergizes with DOX to kill MDA-MB-231 cells.

Conclusions

Hyperoside protects HL-1 cells from DOX-induced cardiotoxicity by inhibiting the ASK1/p38 signaling pathway. Meanwhile, hyperoside maintained the cytotoxicity of DOX in MDA-MB-231 cells.

Dynamic Evolution of Cardiac Function and Glucose and Lipid Metabolism in Ovariectomized Rats and the Intervention Effect of Erxian Decoction

Aims

Abnormal changes in cardiac function have been reported in menopausal women, but there are few clinical studies on this topic. Erxian decoction (EXD) is a classic prescription that is widely used in the treatment of female menopausal diseases. The purpose of this study was to investigate the dynamic evolution of cardiac function and glucose and lipid metabolism in ovariectomized (OVX) rats and the intervention effect of EXD.

Materials and Methods

The OVX climacteric rat model was established by bilateral ovariectomy. After successful modeling, the rats were randomly divided into four groups: the sham operation (SHAM) group (equal volumes of purified water), OVX group (equal volumes of purified water), estradiol (E₂) group (1.8 × 10^-4 g/kg), and EXD group (9 g/kg). Each group of rats was treated for 16 weeks. At the 4^th, 8^th, 12^th, and 16^th weeks after treatment, the cardiac function of the rats in each group was evaluated by ultrasound. The coaxial method was used to measure blood pressure (BP). Serum endothelin-1 (ET-1) and angiotensin-2 (Ang II) levels were determined by the enzyme-linked immunosorbent assay (ELISA). The strip method was used to measure fasting blood glucose (FBG). The serum total cholesterol (TC) and triglyceride (TG) levels of rats were measured with the oxidase method. Direct methods were used to measure serum high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) levels. At week 16 of dosing, serum E₂ levels were determined by E₂ radioimmunoassay. The myocardium and uterus of the rats in each group were stained with HE (hematoxylin-eosin). The ultrastructure of the rat myocardium was observed by electron microscopy.

Results

After the 16^th week of treatment, the serum E₂ level decreased (P < 0.05), and the uterus was atrophied in OVX rats. The cardiac ejection fraction (EF%) decreased at 4 weeks after treatment, and systolic and diastolic function decreased after 12 weeks. After the 16^th week, the EF%, which reflects the "pump" function of the heart, decreased significantly (P < 0.05 or P < 0.01). At the 4^th, 8^th, 12^th, and 16^th weeks of treatment, the systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean pressure (MBP) of the rats in the OVX group increased with time (P < 0.05 or P < 0.01). The serum ET-1 and Ang II levels of rats in the OVX group increased (P < 0.05 or P < 0.01). In the OVX group, FBG was increased (P < 0.05 or P < 0.01), and blood lipids, especially LDL-C, were significantly increased (P < 0.05 or P < 0.01). After the 16^th week of treatment, the myocardial tissue of OVX rats showed obvious pathological changes. EXD significantly increased serum E₂ levels (P < 0.01), decreased ET-1 and Ang II levels (P < 0.01), reduced the cardiac function risk factors BP, FBG, and blood lipids, and significantly improved cardiac function and structural changes in OVX rats (P < 0.05 or P < 0.01).

Conclusions

EXD can improve abnormal cardiac structure and function in OVX rats.

Mechanism of Epimedium intervention in heart failure based on network pharmacology and molecular docking technology

To analyze the pharmacological mechanism of Epimedium in regulating heart failure (HF) based on the network pharmacology method, and to provide a reference for the clinical application of Epimedium in treating HF. Obtaining the main active ingredients and their targets of Epimedium through TCMSP (Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform) database. Access to major HF targets through Genecards, OMIM, PharmGKB, Therapeutic Target Database, Drug Bank database. Protein interaction analysis using String platform and construction of PPI network. Subsequently, Cytoscape software was used to construct the "Epimedium active ingredient-heart failure target" network. Finally, the molecular docking is verified through the Systems Dock Web Site. The core active ingredients of Epimedium to regulate HF are quercetin, luteolin, kaempferol, etc. The core targets are JUN, MYC, TP53, HIF1A, ESR1, RELA, MAPK1, etc. Molecular docking validation showed better binding activity of the major targets of HF to the core components of Epimedium. The biological pathways that Epimedium regulates HF mainly act on lipid and atherosclerotic pathways, PI3K-Akt signaling pathway, and chemoattractant-receptor activation. And its molecular functions are mainly DNA-binding transcription factor binding, RNA polymerase II-specific DNA-binding transcription factor binding, and neurotransmitter receptor activity. This study reveals the multi-component, multi-target and multi-pathway mechanism of action of Epimedium in regulating mental failure, and provides a basis for the clinical development and utilization of Epimedium to intervene in HF.

Icariside II, a Naturally Occurring SIRT3 Agonist, Protects against Myocardial Infarction through the AMPK/PGC-1α/Apoptosis Signaling Pathway

Myocardial infarction (MI) refers to the death of cardiomyocytes triggered by a lack of energy due to myocardial ischemia and hypoxia, and silent mating type information regulation 2 homolog 3 (SIRT3) plays an essential role in protecting against myocardial oxidative stress and apoptosis, which are deemed to be the principal causes of MI. Icariside II (ICS II), one of the main active ingredients of Herbal Epimedii, possesses extensive pharmacological activities. However, whether ICS II can protect against MI is still unknown. Therefore, this study was designed to investigate the effect and possible underlying mechanism of ICS II on MI both in vivo and in vitro. The results showed that pretreatment with ICS II not only dramatically mitigated MI-induced myocardial damage in mice but also alleviated H9c2 cardiomyocyte injury elicited by oxygen and glucose deprivation (OGD), which were achieved by suppressing mitochondrial oxidative stress and apoptosis. Furthermore, ICS II elevated the phosphorylation level of adenosine monophosphate-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α) expression, thereby activating SIRT3. However, these protective effects of ICS II on MI injury were largely abolished in SIRT3-deficient mice, manifesting that ICS II-mediated cardioprotective effects are, at least partly, due to the presence of SIRT3. Most interestingly, ICS II directly bound with SIRT3, as reflected by molecular docking, which indicated that SIRT3 might be a promising therapeutic target for ICS II-elicited cardioprotection in MI. In conclusion, our findings illustrate that ICS II protects against MI-induced oxidative injury and apoptosis by targeting SIRT3 through regulating the AMPK/PGC-1α pathway.

Angelica sinensis Polysaccharide Alleviates Myocardial Fibrosis and Oxidative Stress in the Heart of Hypertensive Rats

This research is aimed at studying the effect of Angelica sinensis polysaccharide (ASP) extracted from the Lixinshui prescription on cardiac disease induced by hypertension in rats. Rat models of cardiovascular disease were established, and the associated factors were measured. The data showed that ASP treatment increased the ejection fraction and short axis shortening rate, while decreasing the LV end-diastolic diameter, LV end-systolic diameter, LV end-diastolic volume, and LV end-systolic volume in HHD rats. ASP downregulated the expression level of TGF-β1, alpha-smooth muscle actin (α-SMA), collagen I, fibronectin, vimentin, Bax, cleaved caspase-9, and cleaved caspase-3 and upregulated the expression level of Bcl-2 in LV of HHD rats. Meanwhile, ASP increased the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased the level of malondialdehyde (MDA), tissue endogenous hydrogen peroxide (H₂O₂), and reactive oxygen species (ROS). Our findings indicated that ASP could prevent hypertensive heart disease by inhibiting myocardial fibrosis, suppressing the myocardial apoptosis, and alleviating oxidative stress.

Microcystin-LR induces ovarian injury and apoptosis in mice via activating apoptosis signal-regulating kinase 1-mediated P38/JNK pathway

As an emerging pollutant in the aquatic environment, microcystin-LR (MC-LR) can enter the body through multiple pathways, and then induce apoptosis and gonadal damage, affecting reproductive function. Previous studies focused on male reproductive toxicity induced by MC-LR neglecting its effects on females. The apoptotic signal-regulated kinase 1 (ASK1) is an upstream protein of P38/JNK pathway, closely associated with apoptosis and organ damage. However, the role of ASK1 in MC-LR-induced reproductive toxicity is unclear. Therefore, this study investigated the role of ASK1 in mouse ovarian injury and apoptosis induced by MC-LR. After MC-LR exposure, ASK1 expression in mouse ovarian granulosa cells was increased at the protein and mRNA levels, and decreased following pretreatment by antioxidant N-acetylcysteine, suggesting that MC-LR-induced oxidative stress has a regulatory role in ASK1 expression. Inhibition of ASK1 expression with siASK1 and NQDI-1 could effectively alleviate MC-LR-induced mitochondrial membrane potential damage and apoptosis in ovarian granulosa cells, as well as pathological damage, apoptosis and the decreased gonadal index in ovaries of C57BL/6 mice. Moreover, the P38/JNK pathway and downstream apoptosis-related proteins (P-P38, P-JNK, P-P53, Fas) and genes (MKK4, MKK3, Ddit3, Mef2c) were activated in vivo and vitro, but their activation was restrained after ASK1 inhibition. Data presented herein suggest that the ASK1-mediated P38/JNK pathway is involved in ovarian injury and apoptosis induced by MC-LR in mice. It is confirmed that ASK1 has an important role in MC-LR-induced ovarian injury, which provides new insights for preventing MCs-induced reproductive toxicity in females.

ICS II protects against cardiac hypertrophy by regulating metabolic remodelling, not by inhibiting autophagy

Cardiac hypertrophy is characterized by a shift in metabolic substrate utilization. Therefore, the regulation of ketone body uptake and metabolism may have beneficial effects on heart injuries that induce cardiac remodelling. In this study, we investigated whether icariside II (ICS II) protects against cardiac hypertrophy in mice and cardiomyocytes. To create cardiac hypertrophy animal and cell models, mice were subjected to transverse aortic constriction (TAC), and embryonic rat cardiomyocytes (H9C2) were stimulated with angiotensin II, a neurohumoral stressor. Both the in vivo and in vitro results suggest that ICS II treatment ameliorated pressure overload–induced cardiac hypertrophy and preserved heart function. In addition, apoptosis and oxidative stress were reduced in the presence of ICS II. Moreover, ICS II inhibited excess autophagy in TAC‐induced hearts and angiotensin II–stimulated cardiomyocytes. Mechanistically, we found that ICS II administration regulated SIRT3 expression in cardiac remodelling. SIRT3 activation increased ketone body transportation and utilization. Collectively, our data show that ICS II attenuated cardiac hypertrophy by modulating ketone body and fatty acid metabolism, and that this was likely due to the activation of the SIRT3‐AMPK pathway. ICS II treatment may provide a new therapeutic strategy for improving myocardial metabolism in cardiac hypertrophy and heart failure.

Thioredoxin-dependent system. Application of inhibitors

One of the systems responsible for maintaining cellular redox homeostasis is the thioredoxin-dependent system. An equally important function of this system is the regulation of the expression of many proteins by the transcription factor NF-κB or the apoptosis regulating kinase (ASK-1). Since it has been shown that the Trx-dependent system can contribute to both the enhancement of tumour angiogenesis and growth as well as apoptosis of neoplastic cells, the search for compounds that inhibit the level/activity of Trx and/or TrxR and thus modulate the course of the neoplastic process is ongoing. It has been shown that many naturally occurring polyphenolic compounds inactivate elements of the thioredoxin system. In addition, the effectiveness of Trx is inhibited by imidazole derivatives, while the activity of TrxR is reduced by transition metal ions complexes, dinitrohalobenzene derivatives, Michael acceptors, nitrosourea and ebselen. In addition, research is ongoing to identify new selective Trx/TrxR inhibitors.

Cilostazol ameliorates diabetic nephropathy by inhibiting highglucose- induced apoptosis

Diabetic nephropathy (DN) is a hyperglycemia-induced progressive development of renal insufficiency. Excessive glucose can increase mitochondrial reactive oxygen species (ROS) and induce cell damage, causing mitochondrial dysfunction. Our previous study indicated that cilostazol (CTZ) can reduce ROS levels and decelerate DN progression in streptozotocin (STZ)-induced type 1 diabetes. This study investigated the potential mechanisms of CTZ in rats with DN and in high glucose-treated mesangial cells. Male Sprague-Dawley rats were fed 5 mg/kg/day of CTZ after developing STZ-induced diabetes mellitus. Electron microscopy revealed that CTZ reduced the thickness of the glomerular basement membrane and improved mitochondrial morphology in mesangial cells of diabetic kidney. CTZ treatment reduced excessive kidney mitochondrial DNA copy numbers induced by hyperglycemia and interacted with the intrinsic pathway for regulating cell apoptosis as an antiapoptotic mechanism. In high-glucose-treated mesangial cells, CTZ reduced ROS production, altered the apoptotic status, and down-regulated transforming growth factor beta (TGF-β) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB). Base on the results of our previous and current studies, CTZ deceleration of hyperglycemia-induced DN is attributable to ROS reduction and thereby maintenance of the mitochondrial function and reduction in TGF-β and NF-κB levels.

The Role of the NOD1/Rip2 Signaling Pathway in Myocardial Remodeling in Spontaneously Hypertensive Rats

BACKGROUND Chronic hypertension changes the function and structure of the heart and blood vessels. This study aimed to explore the role of the NOD1/Rip2 (nucleotide-binding oligomerization domain 1/receptor-interacting protein 2) signaling pathway in myocardial remodeling in spontaneously hypertensive rats (SHRs). MATERIAL AND METHODS Blood pressure was measured using a tail cuff. The cardiac structure was observed using echocardiography. Slices of the myocardium were stained with hematoxylin and eosin. The expression of NOD1 and Rip2 was detected using real-time polymerase chain reaction, western blot, and immunohistochemistry. The content and distribution of collagen in the myocardium were observed using Van Gieson staining. Enzyme-linked immunosorbent assay was used to detect the interleukin-1 (IL-1) concentrations. SHRs were treated with the NOD1 agonist iE-DAP and NOD1 inhibitor ML130. RESULTS The NOD1 agonist increased blood pressure in SHRs, and the NOD1 inhibitor decreased blood pressure; the interventricular septum thickness (IVST) and left ventricular posterior wall thickness (LVPWT) of the agonist-treated group were thicker than those of the control group, and the antagonist exerted the opposite effects. The levels of the NOD1 and Rip2 mRNAs and proteins, serum IL-1 concentration, and myocardial collagen volume fraction (CVF%) increased in SHRs in the NOD1 agonist group, but the levels of NOD1 and Rip2, serum IL-1 concentration, and myocardial collagen volume fraction (CVF%) decreased in SHRs in the NOD1 inhibitor group. CONCLUSIONS NOD1/Rip2 expression increased during the progression of myocardial remodeling in SHRs. The NOD1 agonist increased NOD1 expression and promoted myocardial remodeling, while the NOD1 antagonist reduced NOD1/Rip2 expression and protected against myocardial remodeling.

Icariside II ameliorates myocardial ischemia and reperfusion injury by attenuating inflammation and apoptosis through the regulation of the PI3K/AKT signaling pathway

Icariside II (ICAII) is a bioflavonoid compound which has demonstrated anti-oxidative, anti-inflammatory and anti-apoptotic biological activities. However, to the best of our knowledge, whether ICAII can alleviate myocardial ischemia and reperfusion injury (MIRI) remains unknown. The aim of the present study was to determine whether ICAII exerted a protective effect on MIRI and to investigate the potential underlying mechanism of action. A rat MIRI model was established by ligation of the left anterior descending coronary artery for 30 min, followed by a 24 h reperfusion. Pretreatment with ICAII with or without a PI3K/AKT inhibitor was administered at the beginning of reperfusion. Morphological and histological analyses were detected using hematoxylin and eosin staining; the infarct size was measured using Evans blue and 2,3,5-triphenyltetrazolium chloride staining; and plasma levels of lactate dehydrogenase (LDH) and creatine kinase-myocardial band (CK-MB) were analyzed using commercialized assay kits. In addition, the cardiac function was evaluated by echocardiography and the levels of cardiomyocyte apoptosis were determined using a TUNEL staining. The protein expression levels of Bax, Bcl-2, cleaved caspase-3, interleukin-6, tumor necrosis factor-α, PI3K, phosphorylated (p)-PI3K, AKT and p-AKT were analyzed using western blotting analysis. ICAII significantly reduced the infarct size, decreased the release of LDH and CK-MB and improved the cardiac function induced by IR injury. Moreover, ICAII pretreatment significantly inhibited myocardial apoptosis and the inflammatory response. ICAII also upregulated the expression levels of p-PI3K and p-AKT. However, the protective effects of ICAII were abolished by an inhibitor (LY294002) of the PI3K/AKT signaling pathway. In conclusion, the findings of the present study suggested that ICAII may mitigate MIRI by activating the PI3K/AKT signaling pathway.

Antihypertensive activity of a new c-Jun N-terminal kinase inhibitor in spontaneously hypertensive rats

c-Jun N-terminal kinases (JNKs) are involved in the myocardial and aortic remodeling, increased arterial tone, and arterial blood pressure elevation associated with hypertension. The aim of the present study was to investigate the antihypertensive effect of a new JNK inhibitor, 1H-indeno[1,2-b]quinoxalin-11-one oxime sodium salt (IQ-1S), on spontaneously hypertensive rats (SHRs). Experiments were performed using normotensive Wistar-Kyoto (WKY) rats and SHRs. Experimental groups of SHRs received IQ-1S intragastrically for 6 weeks in daily doses of 5 and 50 mg/kg; experimental groups of WKY rats received 50 mg/kg IQ-1S according to the same regimen. The IQ-1S administration regimen induced decreases in systolic blood pressure, mean arterial blood pressure, total peripheral resistance, blood viscosity, hematocrit, myocardial cell cross-sectional area, and aortic wall thickness in SHRs vs untreated SHRs. There were no significant differences in systolic blood pressure values between the control and experimental groups of WKY rats during the treatment period. A concentration-dependent decrease in the tone of carotid arterial rings isolated from SHRs was observed after JNK inhibitor application in vitro. Application of the JNK inhibitor diminished endothelin-1 secretion by human umbilical vein endothelial cells in vitro. The main mechanisms of the antihypertensive effect of IQ-1S included the attenuation of blood viscosity due to decreased hematocrit, a vasodilatory effect on arterial smooth muscle cells, and a decrease in endothelin-1 production by endothelial cells.

Endoplasmic reticulum stress and focused drug discovery in cardiovascular disease

Endoplasmic reticulum (ER) is an intracellular membranous organelle involved in the synthesis, folding, maturation and post-translation modification of secretory and transmembrane proteins. Therefore, ER is closely related to the maintenance of intracellular homeostasis and the good balance between health and diseases. Endoplasmic reticulum stress (ERS) occurs when unfolded/misfolded proteins accumulate after disturbance of ER environment. In response to ERS, cells trigger an adaptive response called the Unfolded protein response (UPR), which helps cells cope with the stress. In recent years, a large number of studies show that ERS can aggravate cardiovascular diseases. ERS-related proteins expression in cardiovascular diseases is on the rise. Therefore, down-regulation of ERS is critical for alleviating symptoms of cardiovascular diseases, which may be used in the near future to treat cardiovascular diseases. This article reviews the relationship between ERS and cardiovascular diseases and drugs that inhibit ERS. Furthermore, we detail the role of ERS inhibitors in the treatment of cardiovascular disease. Drugs that inhibit ERS are considered as promising strategies for the treatment of cardiovascular diseases.

Icariside II improves myocardial fibrosis in spontaneously hypertensive rats by inhibiting collagen synthesis

OBJECTIVES

We aimed to investigate the effects of icariside II (ICS II) on myocardial fibrosis in spontaneously hypertensive rats (SHRs) and to explore the possible mechanisms.

METHODS

We used SHRs as animal models, and we administered ICS II (4, 8 or 16 mg/kg) orally by gavage for 12 consecutive weeks (Fu et al., Biomed Pharmacother 2018; 100: 64). The left ventricular morphology of the rats was observed using haematoxylin-eosin (HE) staining. The occurrence of myocardial interstitial fibrosis was detected by Masson's trichrome staining. The protein levels of alpha smooth muscle actin (α-SMA), Collagen I, III, matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively), tissue inhibitor of metalloproteinase 1 (TIMP-1), transforming growth factor-β1 (TGF-β1), phospho-Smad2 (p-Smad2), phospho-Smad3 (p-Smad3) and phospho-p38 (p-p38) were examined by Western blotting.

KEY FINDINGS

The results suggested that ICS II improved myocardial interstitial and perivascular collagen deposition and decreased Collagen I/III and α-SMA expression. ICS II (8 and 16 mg/kg) downregulated the expression of MMP-2 and MMP9 and upregulated the expression of TIMP1. In addition, the protein levels of p-Smad2/3, TGF-β1 and p-p38 were decreased by ICS II treatment.

CONCLUSIONS

The results suggest that ICS II can inhibit the expression of Collagen I and Collagen III through the MMP/TIMP-1 and TGF-β1/Smad2,3/p-p38 signalling pathways and that it has therapeutic effects on myocardial fibrosis.

[Role of apoptosis signal-regulating kinase 1 in left ventricular remodeling in mice]

OBJECTIVE

To study the changes and significance of apoptosis signal-regulating kinase 1 (ASK1) in left ventricular remodeling in FVB/N mice.

METHODS

A total of 54 FVB/N mice were randomly divided into 4 groups: 0 d group with 8 mice, 7 d group with 10 mice, 14 d group with 16 mice, and 21 d group with 20 mice. A model of cardiac remodeling was established by intraperitoneal injection of isoproterenol (ISO) at a daily dose of 30 mg/kg, and the 7 d, 14 d, and 21 d groups were injected for 7, 14, and 21 consecutive days respectively. The 0 d group was given intraperitoneal injection of an equal volume of normal saline. Echocardiography was used to measure left ventricular posterior wall thickness at end diastole (dLVPW) and the ratio of heart weight to tibia length (HW/TL) was measured. Hematoxylin-eosin staining was used to measure left ventricular myocardial fiber diameter. Picric-Sirius red staining was used to measure myocardial collagen deposition area in the left ventricle. Quantitative real-time PCR was used to measure the mRNA expression of ASK1, type I collagen (collagen I), and B-type natriuretic peptide (BNP). The mortality rate was observed for each group.

RESULTS

There were gradual increases in HW/TL, myocardial fiber diameter, and dLVPW after 0, 7, and 14 days of ISO injection (P<0.05). There were no significant changes in HW/TL ratio and dLVPW from days 14 to 21 of ISO injection (P>0.05), while there was a significant reduction in myocardial fiber diameter (P<0.05), which was similar to the value on day 7 (P>0.05). There were significant increases in myocardial collagen deposition area and the mRNA expression of collagen I, ASK1, and BNP after 0, 7, 14, and 21 days of ISO injection, which reached the peaks on day 21 (P<0.01). The mRNA expression of ASK1 was positively correlated with myocardial collagen deposition area and the mRNA expression of collagen I and BNP and had a weak correlation with HW/TL, myocardial fiber diameter, and dLVPW. There was a significant increase in the mortality rate of the mice over the time of ISO injection.

CONCLUSIONS

The expression of ASK1 in the myocardium is closely associated with left ventricular remodeling. The increase of ASK1 expression may lead to the aggravation of left ventricular remodeling, and the mechanism of which needs further study.

Icariside II prevents hypertensive heart disease by alleviating endoplasmic reticulum stress via the PERK/ATF-4/CHOP signalling pathway in spontaneously hypertensive rats

OBJECTIVES

Reducing endoplasmic reticulum stress (ERS)-induced cardiomyocyte apoptosis is a key strategy for preventing hypertensive heart disease. In our previous study, Icariside II can improve left ventricular remodelling in spontaneously hypertensive rats (SHRs). This study aims to determine whether Icariside II can exert its effect by inhibiting ERS-induced cardiomyocyte apoptosis via the PERK/ATF-4/CHOP signalling pathway.

METHODS

Spontaneously hypertensive rats were randomly divided into model group and Icariside II groups. The rats in the Icariside II groups were intragastrically administrated with Icariside II 4, 8 and 16 mg/kg from 14 to 26 week-age, respectively. The left ventricular function was measured at the 18, 22 and 26 week-age by small animal ultrasound. At the end of the 26th week, cardiomyocyte apoptosis was analysed and the levels of GRP78, PERK, ATF-4 and CHOP gene and protein were detected.

KEY FINDINGS

The function of left ventricular became declined with age in SHRs, but improved in Icariside II groups. Myocardial apoptosis was aggravated in SHRs, but alleviated in Icariside II groups. Icariside II could reduce the levels of GRP78, PERK, ATF-4, CHOP gene and protein that increased in SHRs.

CONCLUSIONS

Icariside II prevents hypertensive heart disease by alleviating ERS-induced cardiomyocyte apoptosis, and its mechanism is related to the impediment of the PERK/ATF-4/CHOP signalling pathway.

Curcumin Attenuates Inflammation in a Severe Acute Pancreatitis Animal Model by Regulating TRAF1/ASK1 Signaling

Background

Inflammation plays an important role in initiation and development of severe acute pancreatitis (SAP). Curcumin exerts potent anti-inflammatory effects in many diseases, including acute pancreatitis. However, the specific molecular mechanisms are not clear.

Material/Methods

Intra-biliopancreatic duct injection of taurocholate was used to establish an animal model of SAP. Curcumin was administrated to animals as pre-treatments. Concentrations of cytokines in serum and ascites were measured by enzyme-linked immunosorbent assay (ELISA). A colorimetric method was used to determine the amylase activity. Western blotting was used to examine the expression levels and phosphorylation levels of proteins. Immunoprecipitation was used to assess the molecular association between apoptosis signal- regulating kinase 1 (ASK1) and thioredoxin (Trx).

Results

Pre-treatment with curcumin reduced the concentrations of interleukin (IL6) and tumor necrosis factor (TNFα) in serum and ascites, as well as the ascites volume and amylase activity in SAP rats. Pre-treatment with curcumin reduced the expression level of TNF receptor-associated factor 1 (TRAF1), IL6, and TNFα in pancreas in SAP rats. Moreover, the phosphorylation levels of mitogen-activated protein kinase (MAPK) kinase 4 (MKK4), MKK7, and c-Jun NH(2)-terminal protein kinase (JNK) were reduced by curcumin pre-treatment. The molecular association between ASK1 and Trx was recovered by curcumin pre-treatment. As a result, the nuclear translocation of nuclear factor kappa B (NF-κB) was suppressed in pancreases from SAP rats.

Conclusions

Activation of the TRAF1/ASK1/JNK/NF-κB signaling pathway is involved in the inflammation of SAP. Curcumin exerts anti-inflammatory effects by suppressing this proinflammatory pathway.