Effects of stachydrine on norepinephrine-induced neonatal rat cardiac myocytes hypertrophy and intracellular calcium transients

Stachydrine hydrochloride protects the ischemic heart by ameliorating endoplasmic reticulum stress through a SERCA2a dependent way and maintaining intracellular Ca2+ homeostasis

This study aimed to explore the effects and mechanism of action of stachydrine hydrochloride (Sta) against myocardial infarction (MI) through sarcoplasmic/endoplasmic reticulum stress-related injury. The targets of Sta against MI were screened using network pharmacology. C57BL/6 J mice after MI were treated with saline, Sta (6 or 12 mg kg-1) for 2 weeks, and adult mouse and neonatal rat cardiomyocytes (AMCMs and NRCMs) were incubated with Sta (10-4-10-6 M) under normoxia or hypoxia for 2 or 12 h, respectively. Echocardiography, Evans blue, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were used for morphological and functional analyses. Endoplasmic reticulum stress (ERS), unfolded protein reaction (UPR), apoptosis signals, cardiomyocyte contraction, and Ca2+ flux were detected using transmission electron microscopy (TEM), western blotting, immunofluorescence, and sarcomere and Fluo-4 tracing. The ingredient-disease-pathway-target network revealed targets of Sta against MI were related to apoptosis, Ca2+ homeostasis and ERS. Both dosages of Sta improved heart function, decreased infarction size, and potentially increased the survival rate. Sta directly alleviated ERS and UPR and elicited less apoptosis in the border myocardium and hypoxic NRCMs. Furthermore, Sta upregulated sarcoplasmic reticulum Ca2+-ATPase 2a (SERCA2a) in both ischaemic hearts and hypoxic NRCMs, accompanied by restored sarcomere shortening, resting intracellular Ca2+, and Ca2+ reuptake time constants (Tau) in Sta-treated hypoxic ARCMs. However, 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ) (25 μM), a specific SERCA inhibitor, totally abolished the beneficial effect of Sta in hypoxic cardiomyocytes. Sta protects the heart from MI by upregulating SERCA2a to maintain intracellular Ca2+ homeostasis, thus alleviating ERS-induced apoptosis.

Stachydrine ameliorates hypoxia reoxygenation injury of cardiomyocyte via enhancing SIRT1-Nrf2 pathway

BACKGROUND

Hypoxia/reoxygenation (H/R)-induced cardiomyocyte cell apoptosis is critical in developing myocardial infarction. Stachydrine (STA), an active constituent of Leonurus heterophyllus sweet, could have a protective effect on myocardial H/R injury, which remains unexplored. Therefore, the study aimed to investigate the protective effects and mechanisms of STA on H/R injury of cardiomyocytes.

METHODS

Rat cardiomyocyte H9c2 cells underwent H/R (hypoxia for 4 h and reoxygenation for 12 h). Cells were pretreated with STA (50 µM) 2 h before H/R. Cardiomyocyte injury was evaluated by CCK-8 assay and lactate dehydrogenase (LDH) release. Apoptosis was assessed by TUNEL staining and caspase-3 activity. Oxidative stress was assessed by lipid oxidation product MDA and a ROS-scavenging enzyme SOD in culture media. Western blot was performed to measure the protein expressions of SIRT1, Nrf2, and heme oxygenase-1 (HO-1).

RESULTS

STA reversed the decrease in cell viability and increased LDH release in H9c2 cells with the H/R insult. STA significantly suppressed oxidative stress, reduced MDA content, and increased SOD activity in H9c2 cells exposed to H/R. STA reduced apoptosis in H9c2 cells exposed to H/R, as evidenced by the reduced TUNEL positive cells and caspase-3 activity. In addition, STA enhanced SIRT1, Nrf2, and HO-1 protein expression in H/R-stimulated H9c2 cells. SIRT1 and Nrf2 involved the protective effect of STA in H/R-exposed H9c2 cells, as the changes in cell viability and caspase-3 activity by STA can be reversed by SIRT1 inhibitor EX-527 or Nrf2 siRNA.

CONCLUSIONS

Our data speculated that STA protects H/R injury and inhibits oxidative stress and apoptosis in cardiomyocytes by activation of the SIRT1-Nrf2 pathway.

Stachydrine, a Bioactive Equilibrist for Synephrine, Identified from Four Citrus Chinese Herbs

Four Chinese herbs from the Citrus genus, namely Aurantii Fructus Immaturus (Zhishi), Aurantii Fructus (Zhiqiao), Citri Reticulatae Pericarpium Viride (Qingpi) and Citri Reticulatae Pericarpium (Chenpi), are widely used for treating various cardiovascular and gastrointestinal diseases. Many ingredients have already been identified from these herbs, and their various bioactivities provide some interpretations for the pharmacological functions of these herbs. However, the complex functions of these herbs imply undisclosed cholinergic activity. To discover some ingredients with cholinergic activity and further clarify possible reasons for the complex pharmacological functions presented by these herbs, depending on the extended structure-activity relationships of cholinergic and anti-cholinergic agents, a simple method was established here for quickly discovering possible choline analogs using a specific TLC method, and then stachydrine and choline were first identified from these Citrus herb decoctions based on their NMR and HRMS data. After this, two TLC scanning (TLCS) methods were first established for the quantitative analyses of stachydrine and choline, and the contents of the two ingredients and synephrine in 39 samples were determined using the valid TLCS and HPLC methods, respectively. The results showed that the contents of stachydrine (3.04‱) were 2.4 times greater than those of synephrine (1.25‱) in Zhiqiao and about one-third to two-thirds of those of Zhishi, Qingpi and Chenpi. Simultaneously, the contents of stachydrine, choline and synephrine in these herbs present similar decreasing trends with the delay of harvest time; e.g., those of stachydrine decrease from 5.16‱ (Zhishi) to 3.04‱ (Zhike) and from 1.98‱ (Qingpi) to 1.68‱ (Chenpi). Differently, the contents of synephrine decrease the fastest, while those of stachydrine decrease the slowest. Based on these results, compared with the pharmacological activities and pharmacokinetics reported for stachydrine and synephrine, it is indicated that stachydrine can be considered as a bioactive equilibrist for synephrine, especially in the cardio-cerebrovascular protection from these citrus herbs. Additionally, the results confirmed that stachydrine plays an important role in the pharmacological functions of these citrus herbs, especially in dual-directionally regulating the uterus, and in various beneficial effects on the cardio-cerebrovascular system, kidneys and liver.

Stachydrine, a potential drug for the treatment of cardiovascular system and central nervous system diseases

Cardiovascular disease (CVD) is the leading cause of death globally and poses at significant challenge in terms of effective medical treatment. Leonurus japonicus Houtt, a traditional Chinese herb, is widely used in China for the treatment of obstetrical and gynecological disorders, including menstrual disorders, dysmenorrhea, amenorrhea, blood stasis, postpartum bleeding, and blood-related diseases such as CVD. Stachydrine, the main alkaloid component of Leonurus, has been shown to exhibit a wide range of biological activities including anti-inflammatory, antioxidant, anti-coagulant, anti-apoptotic, vasodilator, angiogenic promoter. Additionally, it has been demonstrated to have unique advantages in the prevention and treatment of CVD through regulation of various disease-related signaling pathways and molecular targets. In this comprehensive review, we examine the latest pharmacological effects and molecular mechanisms of Stachydrine in treating cardiovascular and cerebrovascular diseases. Our aim is to solid scientific basis for the development of new CVD drug formulations.

Stachydrine alleviates lipid-induced skeletal muscle insulin resistance via AMPK/HO-1-mediated suppression of inflammation and endoplasmic reticulum stress

OBJECTIVE

Insulin resistance develops due to skeletal muscle inflammation and endoplasmic reticulum (ER) stress. Stachydrine (STA), extracted from Leonurus heterophyllus, has been shown to suppress proliferation and induce apoptosis in breast cancer cells and exert anti-inflammatory properties in the brain, heart, and liver. However, the roles of STA in insulin signaling in skeletal muscle remain unclear. Herein, we examined the impacts of STA on insulin signaling in skeletal muscle under hyperlipidemic conditions and its related molecular mechanisms.

METHODS

Various protein expression levels were determined by Western blotting. Levels of mouse serum cytokines were measured by ELISA.

RESULTS

We found that STA-ameliorated inflammation and ER stress, leading to attenuation of insulin resistance in palmitate-treated C2C12 myocytes. STA dose-dependently enhanced AMPK phosphorylation and HO-1 expression. Administration of STA attenuated not only insulin resistance but also inflammation and ER stress in the skeletal muscle of high-fat diet (HFD)-fed mice. Additionally, STA-ameliorated glucose tolerance and insulin sensitivity, as well as serum TNFα and MCP-1, in mice fed a HFD. Small interfering (si) RNA-associated suppression of AMPK or HO-1 expression abolished the effects of STA in C2C12 myocytes.

CONCLUSIONS

These results suggest that STA activates AMPK/HO-1 signaling, resulting in reduced inflammation and ER stress, thereby improving skeletal muscle insulin resistance. Using STA as a natural ingredient, this research successfully treated insulin resistance and type 2 diabetes.

Stachydrine exhibits a novel antiplatelet property and ameliorates platelet-mediated thrombo-inflammation

BACKGROUND

Platelets are versatile anucleate cells involved in thrombosis as well as inflammation. Stachydrine (STA), a major bioactive compound extracted from Motherwort, has multiple pharmacological properties. Nevertheless, the significance of STA in platelet regulation and whether STA could ameliorate platelet-mediated thrombo-inflammation still remain elusive.

METHODS

Human platelets were used to assess the regulatory effects of STA on platelet activation and interactions with neutrophils in vitro. FeCl₃ injury-induced carotid/mesenteric thrombosis and collagen/epinephrine-induced pulmonary thromboembolism model were used to explore whether STA could regulate thrombosis in vivo. Furthermore, a cecal ligation and puncture-induced sepsis model was employed to investigate the role of STA in thrombo-inflammatory diseases.

RESULTS

STA markedly suppressed platelet activation represented by aggregation, secretion, αIIbβ3-mediated signaling events and calcium mobilization, etc. by inhibiting agonists-induced activation signaling and potentiating cGMP-dependent inhibitory signaling. Mice receiving STA-treated platelets were less susceptible to thrombosis in vivo. In addition, decreased platelet-neutrophil interactions including platelet-neutrophil aggregates and neutrophil extracellular traps, and alleviative sepsis-induced multiorgan damage were observed due to STA-mediated platelet inhibition.

CONCLUSION

This study suggested the potential therapeutic role of STA in thrombotic and thrombo-inflammatory disorders.

Stachydrine hydrochloride ameliorates cardiac hypertrophy through CaMKII/HDAC4/MEF2C signal pathway

Stachydrine hydrochloride (Sta), an activated alkaloid, is isolated from traditional Chinese medicine Yimucao. In previous studies, the cardioprotective effects of Sta were found in our laboratory. However, the underling mechanisms of Sta is not fully elucidated. The aim of this study was to provide a detailed account of the anti-hypertrophic effects of Sta on transcriptional regulation. In vivo, C57BL/6J mice were subjected to transverse aortic constriction (TAC) and were orally treated with Sta. Morphological assessments, echocardiographic parameters, histological analyses and immunofluorescence were used to evaluate cardiac hypertrophy. In vitro, cardiomyocytes were stimulated by phenylephrine (PE), and cell surface and hypertrophy markers were tested by immunofluorescence and real-time polymerase chain reaction (RT-PCR). Moreover, western blotting, RT-PCR and luciferase reporter genes were used to assess the expression of proteins, mRNA and the activity of the CaMKII/HDAC4/MEF2C signal pathway in vivo and in vitro. We found that Sta blocked cardiac hypertrophy induced by pressure overload. We also demonstrated that Sta inhibited nuclear export or promoted nuclear import of HDAC4 through regulation of p-CaMKII, and it further improved the repression of MEF2C. Taken together, our findings demonstrated that Sta ameliorates cardiac hypertrophy through CaMKII/HDAC4/MEF2C signal pathway.

Stachytine Hydrochloride Improves Cardiac Function in Mice with ISO-Induced Heart Failure by Inhibiting the α-1,6-Fucosylation on N-Glycosylation of β1AR

Background: Cardiovascular diseases have become a major public health problem that seriously threatens human health. The cumulative effects of various cardiovascular events will eventually develop into chronic heart insufficiency and even heart failure, and the β1 adrenergic receptor signal pathway plays an important role in this process. Stachytine hydrochloride is the main active ingredient of Yimucao, which is a traditional Chinese medicine used to treat gynecological diseases. Modern studies have found that stachytine hydrochloride has a good cardioprotective effect, but it is still unclear whether stachytine hydrochloride has an effect on the β1 adrenergic receptor signal pathway. The purpose of this study is to explore the effect of stachytine hydrochloride on the β1 adrenergic receptor signal pathway.

Method: In this study, a continuous infusion of isoproterenol (40 mg/kg/day) was administered to mice and ventricular myocytes explored the potential mechanism of stachytine hydrochloride (12 mg/kg/day) on the β1 adrenergic receptor signal pathway in the heart. Evaluate changes in cardiac morphology and function by echocardiography, cardiac hemodynamics, and histological methods, and detect molecular changes by Western blot and immunofluorescence. Treat primary cultured adult mouse or neonatal rat ventricular myocytes with or without isoproterenol (0.1 μMol), PNGase F (10^–2 units/ml), and stachytine hydrochloride (10 μMol) at different time points. Detect α-1,6-fucosylation on N-glycosylation, calcium transient, contraction, and relaxation function and related signals.

Results: Stachytine hydrochloride reduces cardiac remodeling and modulates hemodynamic parameters during chronic β1 adrenergic receptor activation in vivo. The N-glycosylation of β1 adrenergic receptors decreased after continuous isoproterenol stimulation, while stachytine hydrochloride can increase the N-glycosylation of β1AR in the heart of mice with isoproterenol-induced heart failure. Decreased N-glycosylation of β1 adrenergic receptors will downregulate the cAMP/PKA signal pathway and inhibit myocardial excitation and contraction coupling. Stachytine hydrochloride significantly reduced isoproterenol-induced cardiac N-linked glycoproteins with α-1,6-fucosylation.

Conclusion: Our results show that stachytine hydrochloride inhibits the synthesis of α-1,6-fucosylation on the N-terminal sugar chain by reducing α-1,6-fucosyltransferase (FUT8) and α-1,3-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase A (MGAT4a), upregulating the N-glycosylation level on β1 adrenergic receptors, and maintaining cAMP/PKA signal pathway activation.

Harmine is an effective therapeutic small molecule for the treatment of cardiac hypertrophy

Harmine is a β-carboline alkaloid isolated from Banisteria caapi and Peganum harmala L with various pharmacological activities, including antioxidant, anti-inflammatory, antitumor, anti-depressant, and anti-leishmanial capabilities. Nevertheless, the pharmacological effect of harmine on cardiomyocytes and heart muscle has not been reported. Here we found a protective effect of harmine on cardiac hypertrophy in spontaneously hypertensive rats in vivo. Further, harmine could inhibit the phenotypes of norepinephrine-induced hypertrophy in human embryonic stem cell-derived cardiomyocytes in vitro. It reduced the enlarged cell surface area, reversed the increased calcium handling and contractility, and downregulated expression of hypertrophy-related genes in norepinephrine-induced hypertrophy of human cardiomyocytes derived from embryonic stem cells. We further showed that one of the potential underlying mechanism by which harmine alleviates cardiac hypertrophy relied on inhibition of NF-κB phosphorylation and the stimulated inflammatory cytokines in pathological ventricular remodeling. Our data suggest that harmine is a promising therapeutic agent for cardiac hypertrophy independent of blood pressure modulation and could be a promising addition of current medications for cardiac hypertrophy.

Therapeutic Effects of Traditional Chinese Medicine on Cardiovascular Diseases: the Central Role of Calcium Signaling

Calcium, as a second messenger, plays an important role in the pathogenesis of cardiovascular diseases (CVDs). The malfunction of calcium signaling in endothelial cells and vascular smooth muscle cells promotes hypertension. In cardiomyocytes, calcium overload induces apoptosis, leading to myocardial infarction and arrhythmias. Moreover, the calcium–calcineurin–nuclear factor of activated T cells (NFAT) pathway is essential for expressing the cardiac pro-hypertrophic gene. Heart failure is also characterized by reduced calcium transient amplitude and enhanced sarcoplasmic reticulum (SR) calcium leakage. Traditional Chinese medicine (TCM) has been used to treat CVDs for thousands of years in China. Because of its multicomponent and multitarget characteristics, TCM's unique advantages in CVD treatment are closely related to the modulation of multiple calcium handling proteins and calcium signaling pathways in different types of cells involved in distinct CVDs. Thus, we systematically review the diverse mechanisms of TCM in regulating calcium pathways to treat various types of CVDs, ranging from hypertrophic cardiomyopathy to diabetic heart disease.

Schisandrin Protects against Norepinephrine-Induced Myocardial Hypertrophic Injury by Inhibiting the JAK2/STAT3 Signaling Pathway

Aims. Heart failure is closely associated with norepinephrine-(NE-) induced cardiomyocyte hypertrophy. Schisandrin is derived from the traditional Chinese medicine Schisandra; it has a variety of pharmacological activities, and the mechanism of schisandrin-mediated protection of the cardiovascular system is not clear. Main Methods. NE was used to establish a cardiomyocyte hypertrophy model to explore the mechanism of action of schisandrin. An MTT assay was used for cell viability; Hoechst fluorescence staining was used to observe the cell morphology and calculate the apoptosis rate. The cell surface area was measured and the protein to DNA ratio was calculated, changes in mitochondrial membrane potential were detected, and the degree of hypertrophic cell damage was evaluated. WB, QRT-PCR, and immunofluorescence were used to qualitatively, quantitatively, and quantitatively detect apoptotic proteins in the JAK2/STAT3 signaling pathway. Key Findings. In the NE-induced model, schisandrin treatment reduced the apoptosis rate of cardiomyocytes, increased the ratio of the cell surface area to cardiomyocyte protein/DNA, and also, increased the membrane potential of the mitochondria. The expression of both JAK2 and STAT3 was downregulated, and the BAX/Bcl-2 ratio was significantly reduced. In conclusion, schisandrin may protect against NE-induced cardiomyocyte hypertrophy by inhibiting the JAK2/STAT3 signaling pathway and reducing cardiomyocyte apoptosis.

Stachydrine ameliorates the progression of intervertebral disc degeneration via the PI3K/Akt/NF-κB signaling pathway: in vitro and in vivo studies

Intervertebral disc degeneration (IDD) has been reported to be a major cause of low back pain. Stachydrine (STA) is present in the fruit juice of the Citrus genus and Leonurus heterophyllus, in non-negligible concentrations. In our study, we examined the protective effects of STA against IDD development as well as its underlying mechanism of action using both in vitro and in vivo experiments. STA exerted protective effects on the anabolism and catabolism of the extracellular matrix (ECM) in IL-1β-treated NPCs and inhibited the expression of pro-inflammatory factors in vitro. Mechanistically, STA suppressed the IL-1β-induced activation of PI3K/Akt/NF-κB signalling pathway cascades. Moreover, it was also demonstrated in molecular docking studies that STA has strong binding abilities to PI3K. Furthermore, STA ameliorated the progression of the IDD process in vivo in the puncture-induced rat model. In summary, our findings demonstrated that STA ameliorates the progression of IDD via the PI3K/Akt/NF-κB signalling pathway, which makes STA a promising therapeutic agent for the treatment of IDD.

A review of pharmacological and pharmacokinetic properties of stachydrine

Stachydrine is extracted from the leaves of Leonurus japonicus Houtt (or Motherwort, "Yi Mu Cao" in Traditional Chinese Medicine) and is the major bioactive ingredient. So far, stachydrine has demonstrated various bioactivities for the treatment of fibrosis, cardiovascular diseases, cancers, uterine diseases, brain injuries, and inflammation. The pharmacological and pharmacokinetic properties of stachydrine up to 2019 have been comprehensively searched and summarized. This review provides an updated summary of recent studies on the pharmacological activities of stachydrine. Many studies have demonstrated that stachydrine has strong anti-fibrotic properties (on various types of fibrosis) by inhibiting ECM deposition and decreasing inflammatory and oxidative stress through multiple molecular mechanisms (including TGF-β, ERS-mediated apoptosis, MMPs/TIMPs, NF-κB, and JAK/STAT). The cardioprotective and vasoprotective activities of stachydrine are related to its inhibition of β-MHC, excessive autophagy, SIRT1, eNOS uncoupling and TF, promotion of SERCA, and angiogenesis. In addition to its anticancer action, regulation of the uterus, neuroprotective effects, etc. the pharmacokinetic properties of stachydrine are also discussed.

Stachydrine hydrochloride alleviates pressure overload-induced heart failure and calcium mishandling on mice

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine Leonurus japonicus Houtt. has a long history in the treatment of cardiovascular diseases. Stachydrine hydrochloride, the main bioactive ingredient extracted from Leonurus japonicus Houtt., has been shown to have cardioprotective effects. However, the underlying mechanisms of stachydrine hydrochloride haven't been comprehensively studied so far.

AIM OF THE STUDY

The aim of this study was to investigate the protective role of stachydrine hydrochloride in heart failure and elucidate its possible mechanisms of action.

MATERIALS AND METHODS

In vivo, transverse aorta constriction was carried out in C57BL/6J mice, and thereafter, 7.2 mg/kg telmisartan (a selective AT1R antagonist as positive control) and 12 mg/kg stachydrine hydrochloride was administered daily intragastrically for 4 weeks. Cardiac function was evaluated by assessing morphological changes as well as echocardiographic and haemodynamic parameters. In vitro, neonatal rat cardiomyocytes or adult mice cardiomyocytes were treated with stachydrine hydrochloride and challenged with phenylephrine (α-AR agonist). Ventricular myocytes were isolated from the hearts of C57BL/6J mice by Langendorff crossflow perfusion system. Intracellular calcium was measured by an ion imaging system. The length and movement of sarcomere were traced to evaluate the systolic and diastolic function of single myocardial cells.

RESULTS

Stachydrine hydrochloride improved the cardiac function and calcium transient amplitudes, and inhibited the SR leakage and the amount of sparks in cardiac myocytes isolated from TAC mice. We also demonstrated that stachydrine hydrochloride could ameliorated phenylephrine-induced enhance in sarcomere contraction, calcium transients and calcium sparks. Moreover, our data shown that stachydrine hydrochloride blocked the hyper-phosphorylation of CaMKII, RyR2, PLN, and prevented the disassociation of FKBP12.6 from RyR2.

CONCLUSION

Our results suggest that stachydrine hydrochloride exerts beneficial therapeutic effects against heart failure. These cardioprotective effects may be associated with the regulation of calcium handling by stachydrine hydrochloride through inhibiting the hyper-phosphorylation of CaMKII.

Stachydrine Ameliorates Cardiac Fibrosis Through Inhibition of Angiotensin II/Transformation Growth Factor β1 Fibrogenic Axis

Cardiovascular diseases, the leading cause of death worldwide, are tightly associated with the pathological myocardial fibrosis. Stachydrine (Sta), a major active compound in Chinese motherwort Leonurus heterophyllus, was reported to effectively attenuate cardiac fibrosis, but the cellular and molecular mechanism remains unclear. In this study, the anti-fibrotic effect of Sta and mechanism underlying were explored in a mouse model of pressure overload and AngII stimulated cardiac fibroblasts (CFs). Mice were randomly divided into sham, transverse aorta constriction with saline (TAC+Sal), TAC with telmisartan (TAC+Tel), and TAC with Sta (TAC+Sta) groups. Cardiac morphological and functional changes were evaluated by echocardiography and histological methods, and the molecular alterations were detected by western blotting. Primary cultured neonatal mouse CFs were treated with or without angiotensin II (AngII, 10⁻⁷ M), transformation growth factor β1 (TGFβ1, 10 ng/mL), and different dosage of Sta (10⁻⁶–10⁻⁴ M) for up to 96 h, and cell proliferation, cytotoxicity, morphology and related signals were also detected. The in vivo results revealed that TAC prominently induced cardiac dysfunction, left ventricular dilation, myocardial hypertrophy, and elevated myocardial collagen deposition, accompanied with increased fibrotic markers including α-smooth muscle actin (α-SMA) and periostin. However, Sta treatment partially reversed cardiac morphological and functional deteriorations, and significantly blunted cardiac fibrosis as well as Tel. Increments of myocardial angiotensinogen (AGT), angiotensin converting enzyme (ACE), AngII type 1 receptor (AT1R), and TGFβ1 transcripts, together with increased protein levels of ACE and AngII, after TAC were dramatically down-regulated by Sta treatment. Coincidently, in vitro experiments demonstrated that AngII stimulation in CFs led to up-regulation of AT1R and TGFβ1, and therefore promoted CFs trans-differentiating into hyper-activated myocardial fibroblasts (MFs) as evidenced by increased cell proliferation, collagen and fibrotic makers. On the contrary, Sta potently down-regulated but not directly inhibited AT1R, suppressed TGFβ1 production, and the pro-fibrotic effect of AngII in CFs. Moreover, activation of TGFβ1/Smads signal in the fibrotic process were observed both TAC model and in AngII stimulated CFs, which were also notably blunted by Sta. However, Sta failed to abolish the activation of CFs triggered by TGFβ1. Taken together, it was demonstrated in this study that Sta suppressed ACE/AngII/AT1R-TGFβ1 profibrotic axis, especially on the de novo production of AngII via down-regulating AGT/ACE and AT1R, and therefore inactivated CFs and blunted MFs transition, which ultimately prevented cardiac fibrosis.

Benificial Effect of Stachydrine on the Traumatic Brain Injury Induced Neurodegeneration by Attenuating the Expressions of Akt/mTOR/PI3K and TLR4/NFκ-B Pathway

Present investigation aims to explore the protective effect of stachydrine against traumatic brain injury (TBI) and also investigate the molecular mechanism of its action. TBI was induced by the fall a hammer (450 g) from the height of 1.5 m. and later stachydrine was administered for 2 weeks starting 2 hr after the induction of TBI. Effect of stachydrine was determined by estimating modified neurological severity score (mNSS), percentage of water content in the brain and cognitive dysfunction in TBI rats. Moreover western blot assay, histopathology and enzyme linked immunosorbent assay (ELISA) tests were used to determine the effect of stachydrine on TBI injured rats. Result of the report suggests that stachydrine reduces the mNSS and percentage of water content in the brain and also attenuates the cognitive dysfunction in TBI injured rats. However data of western blot assay reports that stachydrine reduces the expression of PI3K/m-TOR/Akt pathway in the brain tissues of TBI rats. Concentration of interleukin (IL-1β), tumor necrosis factor-α (TNF-α) and interferon gamma (INF-γ) was reduces in stachydrine treated group than TBI group. Moreover expression of Nuclear factor-κB/Toll-like receptor 4 (NF-κB/TLR-4) protein was also decreased in stachydrine treated group than TBI group. Histopathology study on brain tissue reveals that the percentage of apoptotic cells was also reduced in stachydrine treated group than TBI group. Data of this investigation concludes that stachydrine protects the neuronal injury by attenuating the phosphatidylinositide 3-kinases/mammalian target of rapamycin/Protein kinase B (PI3K/m-TOR/Akt) and NF-κB/TLR-4 pathway in TBI injured rats.

Alamandine attenuates hypertension and cardiac hypertrophy in hypertensive rats

Oral administration of the peptide alamandine has antihypertensive and anti-fibrotic effects in rats. This work aimed to determine whether subcutaneous alamandine injection would attenuate hypertension and cardiac hypertrophy, and improve the function of a major target of hypertension-related damage, the left ventricle (LV), in spontaneously hypertensive rats (SHRs). This was examined in vivo in SHRs and normotensive rats subjected to 6-week subcutaneous infusion of alamandine or saline control, and in vitro in H9C2-derived and primary neonatal rat cardiomyocytes treated with angiotensin (Ang) II to model cardiac hypertrophy. Tail artery blood pressure measurement and transthoracic echocardiography showed that hypertension and impaired LV function in SHRs were ameliorated upon alamandine infusion. Alamandine administration also decreased the mass gains of heart and lung in SHRs, suppressed cardiomyocyte cross-sectional area expansion, and inhibited the mRNA levels of atrial natriuretic peptide and brain natriuretic peptide. The expression of alamandine receptor Mas-related G protein-coupled receptor, member D was increased in SHR hearts and in cardiomyocytes treated with Ang II. Alamandine inhibited the increases of protein kinase A (PKA) levels in the heart in SHRs and in cardiomyocytes treated with Ang II. In conclusion, the present study showed that alamandine administration attenuates hypertension, alleviates cardiac hypertrophy, and improves LV function. PKA signaling may be involved in the mechanisms underlying these effects.

Isoproterenol-induced cardiac ischemia and fibrosis: Plant-based approaches for intervention

Heart is the most active and incumbent organ of the body, which maintains blood flow, but due to various pathological reasons, several acute and chronic cardiac complications arise out of which myocardial infarction is one of the teething problems. Isoproterenol (ISP)-induced myocardial ischemia is a classical model to screen the cardioprotective effects of various pharmacological interventions. Phytochemicals present a novel option for treating various human maladies including those of the heart. A large number of plant products and their active ingredients have been screened for efficacy in ameliorating ISP-induced myocardial ischemia including coriander, curcumin, Momordica, quercetin, and Withania somnifera. These phytochemicals constituents may play key role in preventing disease and help in cardiac remodeling. Reactive oxygen species scavenging, antiinflammatory, and modulation of various molecular pathways such as Nrf2, NFкB, p-21 activated kinase 1 (PAK1), and p-smad2/3 signaling modulation have been implicated behind the claimed protection. In this review, we have provided a focused overview on the utility of ISP-induced cardiotoxicity, myocardial ischemia, and cardiac fibrosis for preclinical research. In addition, we have also surveyed molecular mechanism of various plant-based interventions screened for cardioprotective effect in ISP-induced cardiotoxicity, and their probable mechanistic profile is summarized.

Jujuboside A attenuates norepinephrine-induced apoptosis of H9c2 cardiomyocytes by modulating MAPK and AKT signaling pathways

Cardiomyocyte apoptosis is closely associated with the pathogenesis of heart failure. Jujuboside A (JUA) is a type of saponin isolated from the seeds of Zizyphus jujuba. In traditional Chinese medicine, it is believed that JUA possesses multiple biological effects, including antianxiety, antioxidant and anti‑inflammatory activities. The present study aimed to evaluate the effects of JUA on norepinephrine (NE)‑induced apoptosis of H9c2 cells and to investigate its underlying mechanisms. Rat H9c2 cardiomyocytes were pretreated with JUA and were then exposed to NE as an in vitro model of myocardial apoptosis. A cell viability assay, scanning electron microscopy, transmission electron microscopy, flow cytometry assay, acridine orange/ethidium bromide staining, reverse transcription‑quantitative polymerase chain reaction and western blotting, all revealed that NE induced H9c2 cell apoptosis. The results demonstrated that NE inhibited cell viability, and enhanced cell damage and apoptosis of H9c2 cells. Conversely, pretreatment with JUA was able to reverse NE‑induced decreased cell viability and increased apoptosis. Furthermore, JUA suppressed upregulation of the B‑cell lymphoma 2 (Bcl‑2)‑associated X protein/Bcl‑2 ratio, and inhibited the increased protein expression levels of cleaved caspase‑3 and cleaved caspase‑9 following NE exposure. However, the protein expression levels of cleaved caspase‑12 and cleaved caspase‑8 were not significantly altered following exposure to NE or JUA pretreatment. In addition, in JUA‑pretreated cells, the protein expression levels of phosphorylated (p)‑p38 and p‑c‑Jun N‑terminal kinase were downregulated compared with in NE‑treated cells. Furthermore, JUA regulated the activation of extracellular signal‑regulated kinase (ERK) in NE‑treated cells and significantly increased the expression levels of p‑AKT. Taken together, these data suggested that JUA may protect against NE‑induced apoptosis of cardiomyocytes via modulation of the mitogen‑activated protein kinase and AKT signaling pathways. Therefore, JUA may be considered a potential therapeutic strategy for the treatment of heart disease.

Stachydrine ameliorates pressure overload-induced diastolic heart failure by suppressing myocardial fibrosis

Stachydrine (Sta), a major constituent of Leonurus japonicus Houtt, has been reported to possess numerous cardioprotective effects. In this study, we evaluated the effect of Sta on pressure overload-induced diastolic heart failure in rats and investigated the mechanisms underlying the effect. Wistar rats were randomized to transverse aortic constriction (TAC) or sham operation. After 3 days, the rats that underwent TAC were randomized to treatment for a total of four experimental groups (n=10 each group): sham operation, TAC only, TAC + telmisartan (Tel), and TAC + stachydrine (Sta). After 12 weeks, we evaluated left ventricular hypertrophy, function, and fibrosis by echocardiography, pressure-volume loop analysis, and histology. In addition, levels of fibrosis-related proteins in the heart were determined by Western blot analysis. Our results showed that Sta significantly suppressed TAC-induced cardiac hypertrophy, and TAC-induced increases in heart weight/body weight and heart weight/tibial length. In addition, Sta attenuated TAC-induced decreases in left ventricular ejection fraction and improved other hemodynamic parameters. Compared with the TAC only group, rats treated with Sta exhibited significant decreases in interstitial and perivascular fibrosis, TGF-βR1 protein levels, and phosphorylation of Smad2/3; however, protein levels of TGF-β1, TGF-βR2, and Smad4 did not differ significantly between the two groups. Taken together, our results demonstrate that Sta protects against diastolic heart failure by attenuating myocardial hypertrophy and fibrosis via the TGF-β/Smad pathway.

Role of PKA in the process of neonatal cardiomyocyte hypertrophy induced by urotensin II

The model of urotensin II (UII)-induced cardiomyocyte hypertrophy has been widely used in studies on hypertrophy. However, the molecular mechanisms responsible for UII-induced cardiomyocyte hypertrophy have not yet been fully elucidated. It has been demonstrated that cardiomyocyte hypertrophy induced by UII is associated with changes in the intracellular Ca2+ concentration. In the present study, we investigated whether the cAMP-dependent protein kinase A (PKA)‑mediated upregulation of the phosphorylation levels of phospholamban (PLN) at Ser16 contributes to UII-induced cardiomyocyte hypertrophy. After primary cultures of neonatal rat cardiomyocytes were exposed to UII for 48 h, cell size, protein/DNA contents and intracellular Ca2+ levels were detected. Western blot analysis was used to quantify the phosphorylated and total forms of PKA, PLN and the total amount of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA)2a. UII increased the cell size, the protein/DNA ratio and the intracellular Ca2+ levels, consistent with the characteristics of hypertrophic response. In addition, exposure to UII upregulated the phosphorylation levels of PKA, and the expression levels of its downstream proteins, PLN and SERCA2a. However, treatment with PKA inhibitor (KT-5720) reversed all these effects of UII. On the whole, our results suggest that UII induces cardiomyocyte hypertrophy through the PKA-mediated upregulation of PLN phosphorylation at Ser16, which provides a new experimental foundation for the prevention and/or treatment of cardiac hypertrophy.

Chronic hypoxia alters fetal cerebrovascular responses to endothelin-1

In utero hypoxia influences the structure and function of most fetal arteries, including those of the developing cerebral circulation. Whereas the signals that initiate this hypoxic remodeling remain uncertain, these appear to be distinct from the mechanisms that maintain the remodeled vascular state. The present study explores the hypothesis that chronic hypoxia elicits sustained changes in fetal cerebrovascular reactivity to endothelin-1 (ET-1), a potent vascular contractant and mitogen. In fetal lambs, chronic hypoxia (3,820-m altitude for the last 110 days of gestation) had no significant effect on plasma ET-1 levels or ETA receptor density in cerebral arteries but enhanced contractile responses to ET-1 in an ETA-dependent manner. In organ culture (24 h), 10 nM ET-1 increased medial thicknesses less in hypoxic than in normoxic arteries, and these increases were ablated by inhibition of PKC (chelerythrine) in both normoxic and hypoxic arteries but were attenuated by inhibition of CaMKII (KN93) and p38 (SB203580) in normoxic but not hypoxic arteries. As indicated by Ki-67 immunostaining, ET-1 increased medial thicknesses via hypertrophy. Measurements of colocalization between MLCK and SMαA revealed that organ culture with ET-1 also promoted contractile dedifferentiation in normoxic, but not hypoxic, arteries through mechanisms attenuated by inhibitors of PKC, CaMKII, and p38. These results support the hypothesis that chronic hypoxia elicits sustained changes in fetal cerebrovascular reactivity to ET-1 through pathways dependent upon PKC, CaMKII, and p38 that cause increased ET-1-mediated contractility, decreased ET-1-mediated smooth muscle hypertrophy, and a depressed ability of ET-1 to promote contractile dedifferentiation.

Stachydrine ameliorates isoproterenol-induced cardiac hypertrophy and fibrosis by suppressing inflammation and oxidative stress through inhibiting NF-κB and JAK/STAT signaling pathways in rats

Cardiac hypertrophy (CH), as one of the major causes of morbidity and mortality in the world, has become an independent and predictive risk factor for adverse cardiovascular events. However, progress in treatment remains sluggish in recent years. Therefore, compounds derived from non-toxic nature plants are urgently needed. Stachydrine (STA), which is isolated from Leonurus, has various activities, including resistance to cardiovascular disease, but little is known about its effect on CH or the mechanisms. We herein investigated the effect of STA on isoproterenol-induced CH and the underlying mechanisms. Treatment with STA significantly increased the ratios of heart weight/body weight, left ventricle weight/body weight and the cross-sectional areas of cardiomyocytes. In addition, STA significantly decreased the mRNA levels of atrial natriuretic peptide, B-type natriuretic peptide and β-myosin heavy chain. Furthermore, isoproterenol-induced fibrosis in rats receiving STA was significant attenuated, as evidenced by decreased ratio of fibrotic area/total area and decreased mRNA levels of collagens I and III. Given down-regulation of interleukin-6, tumor necrosis factor-α, interferon-γ (IFN-γ) and IFN-1β, treatment with STA significantly reversed the expressions of pro-inflammatory induced by isoproterenol. Moreover, STA attenuated the oxidative stress level in serum of isoproterenol-induced CH rats, as shown by increased activity of superoxide dismutase and decreased malondialdehyde level. STA inhibited the expressions of phosphorylated IκBα, NF-κB p65, JAK2 and STAT3 in vivo. Thus, both NF-κB and JAK/STAT signalings played essential roles in mediating the anti-CH effect of STA. Collectively, STA has a potent protective effect on isoproterenol-induced CH, with therapeutic implication for CH.