[Effect and mechanism of Linggui Zhugan Decoction in regulating Sig1R on Angâ ¡-induced cardiomyocyte hypertrophy].

This study aims to explore the mechanism of Linggui Zhugan Decoction(LGZGD) in inhibiting Angiotensin Ⅱ(AngⅡ)-induced cardiomyocyte hypertrophy by regulating sigma-1 receptor(Sig1R). The model of H9c2 cardiomyocyte hypertrophy induced by AngⅡ in vitro was established by preparing LGZGD-containing serum and blank serum. H9c2 cells were divided into normal group, AngⅡ model group, 20% normal rat serum group(20% NSC), and 20% LGZGD-containing serum group. After the cells were incubated with AngⅡ(1 µmol·L~(-1)) or AngⅡ with serum for 72 h, the surface area of cardiomyocytes was detected by phalloidine staining, and the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase were detected by micromethod. The mitochondrial Ca~(2+) levels were detected by flow cytometry, and the expression levels of atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), Sig1R, and inositol 1,4,5-triphosphate receptor type 2(IP_3R_2) were detected by Western blot. The expression of Sig1R was down-regulated by transfecting specific siRNA for investigating the efficacy of LGZGD-containing serum on cardiomyocyte surface area, Na~+-K~+-ATPase activity, Ca~(2+)-Mg~(2+)-ATPase activity, mitochondrial Ca~(2+), as well as ANP, BNP, and IP_3R_2 protein expressions. The results showed that compared with the normal group, AngⅡ could significantly increase the surface area of cardiomyocytes and the expression of ANP and BNP(P<0.01), and it could decrease the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+), and the expression of Sig1R(P<0.01). In addition, IP_3R_2 protein expression was significantly increased(P<0.01). LGZGD-containing serum could significantly decrease the surface area of cardiomyocytes and the expression of ANP and BNP(P<0.05, P<0.01), and it could increase the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+ )(P<0.01), and the expression of Sig1R(P<0.05). In addition, IP_3R_2 protein expression was significantly decreased(P<0.05). However, after Sig1R was down-regulated, the effects of LGZGD-containing serum were reversed(P<0.01). These results indicated that the LGZGD-containing serum could inhibit cardiomyocyte hypertrophy induced by AngⅡ, and its pharmacological effect was related to regulating Sig1R, promoting mitochondrial Ca~(2+ )inflow, restoring ATP synthesis, and protecting mitochondrial function.

The water extract of Amydrium sinense (Engl.) H. Li ameliorates Isoproterenol-induced cardiac hypertrophy through inhibiting the NF-κB signaling pathway.

OBJECTIVE: Pathologic cardiac hypertrophy (PCH) is a precursor to heart failure. Amydrium sinense (Engl.) H. Li (AS), a traditional Chinese medicinal plant, has been extensively utilized to treat chronic inflammatory diseases. However, the therapeutic effect of ASWE on PCH and its underlying mechanisms are still not fully understood. METHODS: A cardiac hypertrophy model was established by treating C57BL/6 J mice and neonatal rat cardiomyocytes (NRCMs) in vitro with isoprenaline (ISO) in this study. The antihypertrophic effects of AS water extract (ASWE) on cardiac function, histopathologic manifestations, cell surface area and expression levels of hypertrophic biomarkers were examined. Subsequently, the impact of ASWE on inflammatory factors, p65 nuclear translocation and NF-κB activation was investigated to elucidate the underlying mechanisms. RESULTS: In the present study, we observed that oral administration of ASWE effectively improved ISO-induced cardiac hypertrophy in mice, as evidenced by histopathological manifestations and the expression levels of hypertrophic markers. Furthermore, the in vitro experiments demonstrated that ASWE treatment inhibited cardiac hypertrophy and suppressed inflammation response in ISO-treated NRCMs. Mechanically, our findings provided evidence that ASWE suppressed inflammation response by repressing p65 nuclear translocation and NF-κB activation. ASWE was found to possess the capability of inhibiting inflammation response and cardiac hypertrophy induced by ISO. CONCLUSION: To sum up, ASWE treatment was shown to attenuate ISO-induced cardiac hypertrophy by inhibiting cardiac inflammation via preventing the activation of the NF-kB signaling pathway. These findings provided scientific evidence for the development of ASWE as a novel therapeutic drug for PCH treatment.

Astragaloside IV mitigates hypoxia-induced cardiac hypertrophy through calpain-1-mediated mTOR activation.

BACKGROUND: Astragaloside IV (AsIV), a key functioning element of Astragalus membranaceus, has been recognized for its potential cardiovascular protective properties. However, there is a need to elucidate the impacts of AsIV on myocardial hypertrophy under hypoxia conditions and its root mechanisms. PURPOSE: This study scrutinized the influence of AsIV on cardiac injury under hypoxia, with particular emphasis on the role of calpain-1 (CAPN1) in mediating mTOR pathways. METHODS: Hypoxia-triggered cardiac hypertrophy was examined in vivo with CAPN1 knockout and wild-type C57BL/6 mice and in vitro with H9C2 cells. The impacts of AsIV, 3-methyladenine, and CAPN1 inhibition on hypertrophy, autophagy, apoptosis, [Ca2+]i, and CAPN1 and mTOR levels in cardiac tissues and H9C2 cells were investigated. RESULTS: Both AsIV treatment and CAPN1 knockout mitigated hypoxia-induced cardiac hypertrophy, autophagy, and apoptosis in mice and H9C2 cells. Moreover, AsIV, 3-methyladenine, and CAPN1 inhibition augmented p-mTOR level but reduced [Ca2+]i and CAPN1 level. Additionally, lentivirus-mediated CAPN1 overexpression in H9C2 cells exacerbated myocardial hypertrophy, apoptosis, and p-mTOR inhibition under hypoxia. Specifically, AsIV treatment reversed the impacts of increased CAPN1 expression on cardiac injury and the inhibition of p-mTOR. CONCLUSION: These findings suggest that AsIV may alleviate cardiac hypertrophy under hypoxia by attenuating apoptosis and autophagy through CAPN1-mediated mTOR activation.

Regulation of Na+-K+-ATPase leads to disturbances of isoproterenol-induced cardiac dysfunction via interference of Ca2+-dependent cardiac metabolism.

Reductions in Na+-K+-ATPase (NKA) activity and expression are often observed in the progress of various reason-induced heart failure (HF). However, NKA α1 mutation or knockdown cannot cause spontaneous heart disease. Whether the abnormal NKA α1 directly contributes to HF pathogenesis remains unknown. Here, we challenge NKA α1+/- mice with isoproterenol to evaluate the role of NKA α1 haploinsufficiency in isoproterenol (ISO)-induced cardiac dysfunction. Genetic knockdown of NKA α1 accelerated ISO-induced cardiac cell hypertrophy, heart fibrosis, and dysfunction. Further studies revealed decreased Krebs cycle, fatty acid oxidation, and mitochondrial OXPHOS in the hearts of NKA α1+/- mice challenged with ISO. In ISO-treated conditions, inhibition of NKA elevated cytosolic Na+, further reduced mitochondrial Ca2+ via mNCE, and then finally down-regulated cardiac cell energy metabolism. In addition, a supplement of DRm217 alleviated ISO-induced heart dysfunction, mitigated cardiac remodeling, and improved cytosolic Na+ and Ca2+ elevation and mitochondrial Ca2+ depression in the NKA α1+/- mouse model. The findings suggest that targeting NKA and mitochondria Ca2+ could be a promising strategy in the treatment of heart disease.

Astragalus polysaccharides alleviates cardiac hypertrophy in diabetic cardiomyopathy via inhibiting the BMP10-mediated signaling pathway.

BACKGROUND: Cardiac hypertrophy can lead to cardiac dysfunction and is closely associated with mortality in diabetic cardiomyopathy (DCM). Astragalus polysaccharides (APS) is the main component extracted from Astragalus membranaceus (Fisch.) Bunge (AM), which exhibits anti-hypertrophic effects on cardiomyocytes in various diseases. However, whether APS exerts anti-hypertrophic effects in DCM remains unclear. PURPOSE: To investigate whether APS can attenuate cardiac hypertrophy in DCM and exert anti-hypertrophic effects by inhibiting the bone morphogenetic protein 10 (BMP10) pathway. METHODS: The anti-hypertrophic effects of APS were studied in high-glucose (HG)-stimulated H9c2 cardiomyocytes and streptozotocin (STZ)-induced DCM rats. BMP10 siRNA was used to inhibit BMP10 expression in H9c2 cardiomyocytes. Cardiac function was assessed by echocardiography. Cardiac hypertrophy was evaluated using heart weight/body weight (HW/BW), RT-PCR, hematoxylin-eosin (HE), and rhodamine phalloidin staining. Changes in hypertrophic components, including BMP10 and downstream factors, were measured using western blotting. RESULTS: In vitro, HG treatment increased the relative cell surface area of H9c2 cardiomyocytes, whereas BMP10 siRNA transfection or APS treatment alleviated the increase induced by HG. APS treatment improved the general condition, increased cardiac function, and decreased the HW/BW ratio, ANP mRNA level, and cardiomyocyte cross-sectional area of DCM rats in vivo. Molecular experiments demonstrated that APS downregulated the levels of the pro-hypertrophic protein BMP10 and its downstream proteins ALK3, BMPRII, and p-Smad1/5/8 without affecting the level of total Smad1/5/8. CONCLUSIONS: Our study demonstrates that APS can alleviate cardiac hypertrophy and protect against DCM by inhibiting activation of the BMP10 pathway. APS is a promising candidate for DCM treatment.

Nitidine chloride induces cardiac hypertrophy in mice by targeting autophagy-related 4B cysteine peptidase.

Nitidine chloride (NC) is a standard active component from the traditional Chinese medicine Zanthoxylum nitidum (Roxb.) DC. (ZN). NC has shown a variety of pharmacological activities including anti-tumor activity. As a number of anti-tumor drugs cause cardiotoxicity, herein we investigated whether NC exerted a cardiotoxic effect and the underlying mechanism. Aqueous extract of ZN (ZNE) was intraperitoneally injected into rats, while NC was injected into beagles and mice once daily for 4 weeks. Cardiac function was assessed using echocardiography. We showed that both ZNE administered in rats and NC administered in mice induced dose-dependent cardiac hypertrophy and dysfunction, whereas administration of NC at the middle and high dose caused death in Beagles. Consistently, we observed a reduction of cardiac autophagy levels in NC-treated mice and neonatal mouse cardiomyocytes. Furthermore, we demonstrated that autophagy-related 4B cysteine peptidase (ATG4B) may be a potential target of NC, since overexpression of ATG4B reversed the cardiac hypertrophy and reduced autophagy levels observed in NC-treated mice. We conclude that NC induces cardiac hypertrophy via ATG4B-mediated downregulation of autophagy in mice. Thus, this study provides guidance for the safe clinical application of ZN and the use of NC as an anti-tumor drug.

Diacerein alleviates Ang II-induced cardiac inflammation and remodeling by inhibiting the MAPKs/c-Myc pathway.

BACKGROUND: Heart failure is a common event in the course of hypertension. Recent studies have highlighted the key role of the non-hemodynamic activity of angiotensin II (Ang II) in hypertension-related cardiac inflammation and remodeling. A naturally occurring compound, diacerein, exhibits anti-inflammatory activities in various systems. HYPOTHESIS/PURPOSE: In this study, we have examined the potential effects of diacerein on Ang II-induced heart failure. METHODS: C57BL/6 mice were administered Ang II by micro-osmotic pump infusion for 4 weeks to develop hypertensive heart failure. Mice were treated with diacerein by gavage for final 2 weeks. RNA-sequencing analysis was performed to explore the potential mechanism of diacerein. RESULTS: We found that diacerein could inhibit inflammation, myocardial fibrosis, and hypertrophy to prevent heart dysfunction, without the alteration of blood pressure. To explore the potential mechanism of diacerein, RNA-sequencing analysis was performed, indicating that MAPKs/c-Myc pathway is involved in that cardioprotective effects of Diacerein. We further confirmed that diacerein inhibits Ang II-activated MAPKs/c-Myc pathway to reduce inflammatory response in mouse hearts and cultured cardiomyocytes. Deficiency of MAPKs or c-Myc in cardiomyocytes abolished the anti-inflammatory effects of diacerein. CONCLUSION: Our results indicate that diacerein protects hearts in Ang II-induced mice through inhibiting MAPKs/c-Myc-mediated inflammatory responses, rendering diacerein a potential therapeutic candidate agent for hypertensive heart failure.

Tabersonine attenuates Angiotensin II-induced cardiac remodeling and dysfunction through targeting TAK1 and inhibiting TAK1-mediated cardiac inflammation.

BACKGROUND: Angiotensin II (Ang II)-induced cardiac inflammation contribute to pathological cardiac remodeling and hypertensive heart failure (HF). Tabersonine (Tab) is an indole alkaloid mainly isolated from Catharanthus roseus and exhibits anti-inflammatory activity in various systems. However, the role of Tab in hypertensive HF and its molecular targets remains unknown. HYPOTHESIS/PURPOSE: We aimed to investigate potential cardioprotective effects and mechanism of Tab against Ang II-induced cardiac injuries. METHODS: C57BL/6 mice were administered Ang II (at 1000 ng/kg/min) by micro-osmotic pump infusion for 30 days to develop hypertensive HF. Tab at 20 and 40 mg/kg/day was administered during the last 2 weeks to elucidate the cardioprotective properties. Cultured cardiomyocyte-like H9c2 cells and rat primary cardiomyocytes were used for mechanistic studies of Tab. RESULTS: We demonstrate for the first time that Tab provides protection against Ang II-induced cardiac dysfunction in mice, associated with reduced cardiac inflammation and fibrosis. Mechanistically, we show that Tab may interacts with TAK1 to inhibit Ang II-induced TAK1 ubiquitination and phosphorylation. Disruption of TAK1 activation by Tab blocked downstream NF-κB and JNK/P38 MAPK signaling activation and decreased cardiac inflammation and fibrosis both in vitro and in vivo. TAK1 knockdown also blocked Ang II-induced cardiomyocytes injuries and prevented the innately pharmacological effects of Tab. CONCLUSION: Our results indicate that Tab protects hearts against Ang II-mediated injuries through targeting TAK1 and inhibiting TAK1-mediated inflammatory cascade and response. Thus, Tab may be a potential therapeutic candidate for hypertensive HF.

Urban fine particulate matter causes cardiac hypertrophy through calcium-mediated mitochondrial bioenergetics dysfunction in mice hearts and human cardiomyocytes.

In recent years, the cardiovascular toxicity of urban fine particulate matter (PM2.5) has sparked significant alarm. Mitochondria produce 90% of ATP and make up 30% of the volume of cardiomyocytes. Thus knowledge of myocardial mitochondrial dysfunction due to PM2.5 exposure is essential for further cardiotoxic effects. Here, the mechanism of PM2.5-induced cardiac hypertrophy through calcium overload and mitochondrial dysfunction was investigated in vivo and in vitro. Male and female BALB/c mice were given 1.28, 5.5, and 11 mg PM2.5/kg bodyweight weekly through oropharyngeal inhalation for four weeks and were assigned to low, medium, and high dose groups, respectively. PM2.5-induced myocardial edema and cardiac hypertrophy were detected in the high-dose group. Mitochondria were scattered and ruptured with abnormal ultrastructural morphology. In vitro experiments on human cardiomyocyte AC16 showed that exposure to PM2.5 for 24 h caused opened mitochondrial permeability transition pore --leading to excessive calcium production, decreased mitochondrial membrane potential, weakened mitochondrial respiratory metabolism capacity, and decreased ATP production. Nevertheless, the administration of calcium chelator ameliorated the mitochondrial damage in the PM2.5-treated group. Our in vivo and in vitro results confirmed that calcium overload under PM2.5 exposure triggered mTOR/AKT/GSK-3ß activation, leading to mitochondrial bioenergetics dysfunction and cardiac hypertrophy.

Valencene post-treatment exhibits cardioprotection via inhibiting cardiac hypertrophy, oxidative stress, nuclear factor- κB inflammatory pathway, and myocardial infarct size in isoproterenol-induced myocardial infarcted rats; A molecular study.

The growing burden of myocardial infarction (MI) becomes a major global health issue that is accountable for considerable mortality worldwide. Hence, it is obligatory to develop a new treatment for MI having lesser side effects. Cardiac hypertrophy, oxidative stress, and inflammatory pathways play crucial roles in the pathogenesis of MI. This investigation established the anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects of valencene. Rats were induced MI by isoproterenol (100 mg/kg body weight) and then treated with valencene and cardiac sensitive markers, cardiac hypertrophy, oxidative stress, markers of inflammation, nuclear factor- κB inflammatory pathway, and myocardial infarct size was estimated/determined. The serum cardiac diagnostic markers, cardiac hypertrophy, conjugated dienes, markers of inflammation, pro-inflammatory cytokines, and myocardial infarct size were significantly (P < 0.05) increased by isoproterenol. Further, antioxidant enzymes and anti-inflammatory cytokine gene were significantly (P < 0.05) decreased in the heart. The 2, 3, 5-triphenyl tetrazolium chloride dye staining revealed a larger infarct size. Moreover, histological results of myocardial infarcted rat's cardiac tissue revealed separation of cardiac muscle fibers, necrosis, and inflammatory cells. Post-treatment with valencene (12 mg/kg body weight) orally, daily, for two weeks to isoproterenol-induced myocardial infarcted rats reversed all above said structural, biochemical, molecular, and histological parameters investigated, by its anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects. Thus, valencene is a potential candidate for inhibiting cardiac hypertrophy, oxidative stress, nuclear factor- κB inflammatory pathway, and myocardial infarct size and exhibited cardioprotection in MI.

Smilax glabra Roxb. flavonoids protect against pathological cardiac hypertrophy by inhibiting the Raf/MEK/ERK pathway: In vivo and in vitro studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Smilax glabra Roxb., the dry rhizome of Sarsaparilla, which is also known as Tu fuling (TFL) in China, is a well-known traditional CHINESE medicine that is widely used for detoxication, relieving dampness and as a diuretic. We have previously shown that the extracted TFL flavonoids (designated TFLF) possess anti-cardiac hypertrophy effects in vitro. However, the anti-cardiac hypertrophy effects of TFLF in vivo and the underlying mechanisms remain to be elucidated. AIM OF THE STUDY: To reveal the underlying therapeutic mechanism of TFLF on cardiac hypertrophy by using transverse aortic constriction (TAC) model and cellular assays in vitro. MATERIAL & METHODS: Cardiac hypertrophy was replicated by TAC surgery in rats or by isoprenaline treatment of rat H9C2 myocardial cells in vitro. Cardiac structure and function were evaluated by echocardiographic and hemodynamic examinations in vivo and histological analysis of tissues ex vivo. Biochemical kits and quantitative PCR were used to analyze markers of cardiac hypertrophy. Expression and phosphorylation of key proteins in the Raf/MEK/ERK pathway were quantified by Western blotting. We further confirmed our findings in H9C2 rat cardiomyocytes treated with isoprenaline and the ERK inhibitor in vitro. RESULTS: TFLF attenuated cardiac hypertrophy and fibrosis and improved cardiac dysfunction in TAC rats. TFLF treatment induced a strong reduction in serum NT-proBNP levels. Cardiac hypertrophy marker gene (ANP, BNP and ß-MHC) expression and the phosphorylation levels of c-Raf and ERK1/2 were decreased by TFLF treatment. TFLF also protected H9C2 cells from isoprenaline-induced hypertrophy in vitro via a similar molecular mechanism as that observed in the rat heart. Moreover, pretreatment with TRLF and the ERK inhibitor further inhibited the mRNA overexpression of hypertrophic genes in vitro. CONCLUSIONS: TFLFs may protect against pathological cardiac hypertrophy via negative regulation of the Raf/MEK/ERK pathway. Thus, TFLFs are implicated as a potential pharmacological agent for treating cardiac hypertrophy in clinical practice.

Metabolomics and integrated network pharmacology analysis reveal attenuates cardiac hypertrophic mechanisms of HuoXin pill.

ETHNOPHARMACOLOGICAL RELEVANCE: Cardiac hypertrophy (CH) is maladaptive and contributes to the pathogenesis of heart failure. Huoxin pill (HXP), a Chinese herbal prescription, is widely applied in the treatment of cardiovascular disease (CAD). Its mechanism, however, is unclear. AIM OF THE STUDY: This study investigated the mechanism of action for Huoxin pill in the treatment of CH, an important stage of CAD. MATERIALS AND METHODS: A total of 60 rats were injected with isoprenaline (ISO) to establish a model of CH. Echocardiography and histopathologic evaluation were performed to evaluate the disease severity, whereas ELISAs were conducted to determine the expression of oxidative stress. Network pharmacology and metabolomic analyses were conducted to identify the key compounds, core targets and pathways that mediate the effects of HXP against CH. Western blotting and immunohistochemistry were used to test apoptosis protein levels. RESULTS: HXP administration in ISO-treated rats decreased hypertrophy indices, alleviated cardiac pathological damage, and downregulated oxidative stress levels when compared to those of rats subjected to ISO treatment only. Moreover, network pharmacology results suggested that the PI3K-Akt pathway is a main mechanism by which HXP inhibits cardiac hypertrophy, and experimental verification showed that HXP inhibited cardiomyocyte apoptosis via activation of the PI3K-Akt pathway. The results of metabolomic analysis identified 21 differential metabolites between the HXPH group and ISO group, which were considered to be metabolic biomarkers of HXP in the treatment of CH. Among them, 6 differential metabolites were significantly upregulated, and 15 were significantly downregulated. CONCLUSIONS: The present study presents an integrated strategy for investigating the mechanisms of HXP in the treatment of CH and sheds new light on the application of HXP as a traditional Chinese medicine.

LongShengZhi alleviated cardiac remodeling via upregulation microRNA-150-5p with matrix metalloproteinase 14 as the target.

ETHNOPHARMACOLOGICAL RELEVANCE: LongShengZhi capsule (LSZ), a traditional Chinese medicine, is used for treatment of patients with vascular diseases. LSZ reduced doxorubicin-induced heart failure by reducing production of reactive oxygen species and inhibiting inflammation and apoptosis. AIM OF THE STUDY: This study was to explore whether LSZ could alleviate cardiac remodeling via upregulation of microRNA (miR)-150-5p and the downstream target. Cardiac remodeling was induced by Ang II in vivo and in vitro. RESULTS: LSZ attenuated Ang II-induced cardiac hypertrophy and fibrosis in rats, and in primary cardiomyocytes (CMs) and primary cardiac fibroblasts (CFs). MiR-150-5p was downregulated in Ang II-induced rat heart, CMs and CFs, and these decreases were reserved by LSZ. In vivo overexpression of miR-150-5p by transfection of miR-150-5p agomiR protected Ang II-induced cardiac hypertrophy and fibrosis in rats. Meanwhile, its overexpression also reversed Ang II-induced upregulation of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and ß-myosin heavy chain (ß-MHC) in rat hearts and primary CMs, as well as upregulation of collagen I, collagen III and transforming growth factor-ß (TGF-ß) in rat hearts and primary CFs. Matrix metalloproteinase 14 (MMP14) was validated as the target gene of miR-150-5p, which was overexpressed in Ang II-induced rat heart, rat primary CMs and primary CFs. Notably, overexpression of MMP14 induced cardiac remodeling, and reversed the protective role of miR-150-5p in downregulating Ang II-induced upregulation of hypertrophy and fibrosis markers in vitro. CONCLUSION: Collectively, LSZ protects Ang II-induced cardiac dysfunction and remodeling via upregulation of miR-150-5p to target MMP14. Administration of LSZ, upregulation of miR-150-5p or targeting of MMP14 may be strategies for cardiac remodeling therapy.

Comparing the effects of Portulaca oleracea seed hydro-alcoholic extract, valsartan, and vitamin E on hemodynamic changes, oxidative stress parameters and cardiac hypertrophy in thyrotoxic rats.

The present study compared the effects of Portulaca oleracea (P. oleracea) seed hydro-alcoholic extract, valsartan, and vitamin E on hemodynamic changes, oxidative stress markers and cardiac hypertrophy in a model of thyrotoxicosis. The hyperthyroid state was induced by intraperitoneal injection of levothyroxine (100 µg/kg) for 4 weeks in male adult rats. After 2 weeks, vitamin E (20 mg/kg), valsartan (8 mg/kg), and P. oleracea seed extract (400 mg/kg) were administered in three groups of thyrotoxic rats. The control group was given a daily injection of normal saline. Systolic blood pressure and heart rate were measured on three occasions with tail cuff. At the end of the fourth week, the animals were scarified and serum samples and heart tissue were collected for biochemical and histological studies. The levothyroxine increased heart rate and systolic blood pressure. A lower heart rate and reduced systolic blood pressure were observed in groups receiving valsartan and P. oleracea extract. The heart weight/body weight ratio increased in groups treated with levothyroxine, but in a microscopic study, cardiomyocyte width was not different between the groups. Levothyroxine increased the level of malondyaldehide and NO metabolite but reduced the thiol concentration, superoxide dismutase, and catalase activities. However, treatment with vitamin E and P. oleracea extract increased the thiol concentration, superoxide dismutase and catalase activities while decreasing malondyaldehide level. In addition, treatment with P. oleracea extract and valsartan decreased NO metabolite level. Treatment with P. oleracea extract improved levothyroxine induced oxidative stress and hemodynamic changes. These effects may be for antioxidant components.

[Chikusetsu saponin â £a ameliorates myocardial hypertrophy of rats through regulating expression of miR199a-5p/Atg5].

The present study investigated the effects of chikusetsu saponin Ⅳa(CHS Ⅳa) on isoproterenol(ISO)-induced myocardial hypertrophy in rats and explored the underlying molecular mechanism. ISO was applied to establish a rat model of myocardial hypertrophy, and CHS Ⅳa(5 and 15 mg·kg~(-1)·d~(-1)) was used for intervention. The tail artery blood pressure was measured. Cardiac ultrasound examination was performed. The ratio of heart weight to body weight(HW/BW) was calculated. Morphological changes in the myocardial tissue were observed by HE staining. Collagen deposition in the myocardial tissue was observed by Masson staining. The mRNA expression of myocardial hypertrophy indicators(ANP and BNP), autophagy-related genes(Atg5, P62 and beclin1), and miR199 a-5 p was detected by qRT-PCR. Atg5 protein expression was detected by Western blot. The results showed that the model group exhibited increased tail artery blood pressure and HW/BW ratio, thickened left ventricular myocardium, enlarged myocardial cells, disordered myocardial fibers with widened interstitium, and a large amount of collagen aggregating around the extracellular matrix and blood vessels. ANP and BNP were largely expressed. Moreover, P62 expression was up-regulated, while beclin1 expression was down-regulated. After intervention by CHS Ⅳa at different doses, myocardial hypertrophy was ameliorated and autophagy activity in the myocardial tissue was enhanced. Meanwhile, miR199 a-5 p expression declined and Atg5 expression increased. As predicted by bioinformatics, Atg5 was a target gene of miR199 a-5 p. CHS Ⅳa was capable of preventing myocardial hypertrophy by regulating autophagy of myocardial cells through the miR-199 a-5 p/Atg5 signaling pathway.

Modified citrus pectin prevents isoproterenol-induced cardiac hypertrophy associated with p38 signalling and TLR4/JAK/STAT3 pathway.

Modified citrus pectin (MCP) is a specific inhibitor of galectin-3 (Gal-3) that is regarded as a new biomarker of cardiac hypertrophy, but its effect is unclear. The aim of this study is to investigate the role and mechanism of MCP in isoproterenol (ISO)-induced cardiac hypertrophy. Rats were injected with ISO to induce cardiac hypertrophy and treated with MCP. Cardiac function was detected by ECG and echocardiography. Pathomorphological changes were evaluated by the haematoxylin eosin (H&E) and wheat germ agglutinin (WGA) staining. The hypertrophy-related genes for atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and ß-myosin heavy chain (ß-MHC), and the associated signal molecules were analysed by qRT-PCR and western blotting. The results show that MCP prevented cardiac hypertrophy and ameliorated cardiac dysfunction and structural disorder. MCP also decreased the levels of ANP, BNP, and ß-MHC and inhibited the expression of Gal-3 and Toll-like receptor 4 (TLR4). Additionally, MCP blocked the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), but it promoted the phosphorylation of p38. Thus, MCP prevented ISO-induced cardiac hypertrophy by activating p38 signalling and inhibiting the Gal-3/TLR4/JAK2/STAT3 pathway.

Plantago asiatica L. seeds extract protects against cardiomyocyte injury in isoproterenol- induced cardiac hypertrophy by inhibiting excessive autophagy and apoptosis in mice.

BACKGROUND: Cardiac hypertrophy is the early stage of many heart diseases, such as coronary heart disease, hypertension, valvular dysfunction and cardiomyopathy. Cardiomyocyte autophagy and apoptosis play an important role in the process of cardiac hypertrophic response. Plantago asiatica L. seeds extract (PASE) is prepared from a traditional herbal medicine in Asia with tremendous pharmacological activities. However, whether PASE could relieve cardiac hypertrophy has not been elucidated. The present study is aimed to investigate the effect of PASE on cardiac hypertrophy and explore its potential underlying mechanism. METHODS: Cardiac hypertrophy was induced in C57BL/6 mice by subcutaneous injection of isoproterenol (ISO) for two weeks. Meanwhile, the mice were intraperitoneally injected with PASE at dosages of 20, 40 and 80 mg/kg/day. Cardiac hypertrophy was evaluated by echocardiographic examination, haematoxylin and eosin staining and quantitative real-time polymerase chain reaction. Expressions of proteins involved in autophagy and apoptosis such as Beclin1, p62, LC3II, Bax, Bcl-2 and Cleaved-caspase-3 were detected by western blot analysis. Western blot, transient transfection, acridine orange staining, TUNEL staining and autophagy inducer were used to observe the effect and explore the mechanism of PASE on cardiomyocyte and H9c2 cells with excessive autophagy and apoptosis induced by ISO. RESULTS: ISO induction for two weeks disturbed the myocardial contractility and cardiac function of left ventricles of mice. PASE treated mice showed significantly improved cardiac function indexes, including EF, FS, SV and CO, compared with the ISO group. Treatment with PASE also decreased the heart weight/body weight ratio and cardiomyocyte size, and downregulated the mRNA and protein expressions of hypertrophic markers ANP, BNP, and ß-MHC. Furthermore, the changes of autophagy and apoptosis markers, such as LC3II, Beclin1, p62, Bcl-2, Bax and Cleaved-caspase-3 induced by ISO were resumed by PASE treatment. Consistently, PASE demonstrated similar effects on ISO-induced H9c2 cells as it did in vivo. In addition, PASE could counteract the increased autophagy induced by the autophagy inducer, rapamycin. CONCLUSION: PASE attenuated ISO-induced cardiac hypertrophy in mice by inhibiting excessive autophagy and apoptosis in cardiomyocytes. The novel findings may pave the way for the clinical usage of PASE for the prevention of heart diseases related with cardiac hypertrophy.

Baicalein attenuates cardiac hypertrophy in mice via suppressing oxidative stress and activating autophagy in cardiomyocytes.

Baicalein is a natural flavonoid extracted from the root of Scutellaria baicalensis that exhibits a variety of pharmacological activities. In this study, we investigated the molecular mechanisms underlying the protective effect of baicalein against cardiac hypertrophy in vivo and in vitro. Cardiac hypertrophy was induced in mice by injection of isoproterenol (ISO, 30 mg·kg-1·d-1) for 15 days. The mice received caudal vein injection of baicalein (25 mg/kg) on 3rd, 6th, 9th, 12th, and 15th days. We showed that baicalein administration significantly attenuated ISO-induced cardiac hypertrophy and restored cardiac function. The protective effect of baicalein against cardiac hypertrophy was also observed in neonatal rat cardiomyocytes treated with ISO (10 µM). In cardiomyocytes, ISO treatment markedly increased reactive oxygen species (ROS) and inhibited autophagy, which were greatly alleviated by pretreatment with baicalein (30 µM). We found that baicalein pretreatment increased the expression of catalase and the mitophagy receptor FUN14 domain containing 1 (FUNDC1) to clear ROS and promote autophagy, thus attenuated ISO-induced cardiac hypertrophy. Furthermore, we revealed that baicalein bound to the transcription factor FOXO3a directly, promoting its transcription activity, and transactivated catalase and FUNDC1. In summary, our data provide new evidence for baicalein and FOXO3a in the regulation of ISO-induced cardiac hypertrophy. Baicalein has great potential for the treatment of cardiac hypertrophy.

Melatonin alleviates angiotensin-II-induced cardiac hypertrophy via activating MICU1 pathway.

Mitochondrial calcium uptake 1 (MICU1) is a pivotal molecule in maintaining mitochondrial homeostasis under stress conditions. However, it is unclear whether MICU1 attenuates mitochondrial stress in angiotensin II (Ang-II)-induced cardiac hypertrophy or if it has a role in the function of melatonin. Here, small-interfering RNAs against MICU1 or adenovirus-based plasmids encoding MICU1 were delivered into left ventricles of mice or incubated with neonatal murine ventricular myocytes (NMVMs) for 48 h. MICU1 expression was depressed in hypertrophic myocardia and MICU1 knockdown aggravated Ang-II-induced cardiac hypertrophy in vivo and in vitro. In contrast, MICU1 upregulation decreased cardiomyocyte susceptibility to hypertrophic stress. Ang-II administration, particularly in NMVMs with MICU1 knockdown, led to significantly increased reactive oxygen species (ROS) overload, altered mitochondrial morphology, and suppressed mitochondrial function, all of which were reversed by MICU1 supplementation. Moreover, peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α)/MICU1 expression in hypertrophic myocardia increased with melatonin. Melatonin ameliorated excessive ROS generation, promoted mitochondrial function, and attenuated cardiac hypertrophy in control but not MICU1 knockdown NMVMs or mice. Collectively, our results demonstrate that MICU1 attenuates Ang-II-induced cardiac hypertrophy by inhibiting mitochondria-derived oxidative stress. MICU1 activation may be the mechanism underlying melatonin-induced protection against myocardial hypertrophy.

An α2-adrenoceptor agonist: Dexmedetomidine induces protective cardiomyocyte hypertrophy through mitochondrial-AMPK pathway.

Aims: Dexmedetomidine (Dex) as a highly selective α2-adrenoceptor agonist, was widely used anesthetic in perioperative settings, whether Dex induces cardiac hypertrophy during perioperative administration is unknown. Methods: The effects of Dex on cardiac hypertrophy were explored using the transverse aortic constriction model and neonatal rat cardiomyocytes. Results: We reported that Dex induces cardiomyocyte hypertrophy with activated ERK, AKT, PKC and inactivated AMPK in both wild-type mice and primary cultured rat cardiomyocytes. Additionally, pre-administration of Dex protects against transverse aortic constriction induced-heart failure in mice. We found that Dex up-regulates the activation of ERK, AKT, and PKC via suppression of AMPK activation in rat cardiomyocytes. However, suppression of mitochondrial coupling efficiency and membrane potential by FCCP blocks Dex induced AMPK inactivation as well as ERK, AKT, and PKC activation. All of these effects are blocked by the α2-adrenoceptor antagonist atipamezole. Conclusion: The present study demonstrates Dex preconditioning induces cardiac hypertrophy that protects against heart failure through mitochondria-AMPK pathway in perioperative settings.