Effect of microparticles derived from bone marrow mesenchymal stem cells on cardiomyocyte hypertrophy and its mechanism / 中国生物制品学杂志

@#Objective To investigate the effect of microparticles(MPs)derived from bone marrow mesenchymal stem cells(BMSCs) on myocardial hypertrophy and its mechanism.Methods The osteogenic differentiation and adipogenic differentiation of mesenchymal stem cells(MSCs) were induced. After isolation and purification,the morphological characteristics were observed by transmission electron microscope,and the MPs surface antigen was identified by flow cytometry. Myocardial hypertrophy model was induced by using isoprenaline(ISO)in rats,which were measured for the cardiac structure and function by echocardiography,and then detected for various indexes of the heart and isolated left ventricle. Single ventricular myocytes of rats were acutely isolated and divided into control group(Control group),cardiomyocyte hypertrophy group(ISO group),MPs group(MPs group),and MPs supernatant group(Supernatant group). The mRNA expressions of atrial natriuretic peptide(ANP)and B-type natriuretic peptide(BNP)were detected by qRTPCR. The expression levels of calmodulin-dependent protein kinaseⅡ（CaMKⅡ）and phosphorylated calmodulin-dependent protein kinaseⅡ（p-CaMKⅡ）were detected by ELISA. The L-type calcium current(LCa-L)in single ventricular myocyte of various groups was recorded by whole-cell patch clamp.Results The bone nodules of MSCs osteogenic differentiation turned red after alizarin red staining,and lipid droplets of adipogenic differentiation turned red after oil red O staining;Under transmission electron microscope,MPs membrane had a complete structure,a clear outline and a diameter of about200 nm;The positive rates of CD29 and CD90 on the surface of MPs were(98. 24 ± 0. 82)% and(97. 69 ± 1. 83)%,respectively. Compared with Control group,the left ventricular end diastolic dimension(LVEDD)reduced signifi-cantly(t =5. 065,P < 0. 05),while the interventricular septum end-diastolic dimension(IVSd),left ventricular posterior wall dimension(LVPWd),heart weight to body weight ratio(HW/BW),and heart weight to tibial length ratio(HW/Tibia)significantly increased in ISO group(t = 4. 013,2. 368,4. 392,5. 043 and 6. 120,respectively,each P < 0. 05),indicating that the hypertrophic model was successfully established. The expression levels of ANP and BNP mRNA in hypertrophic cardiomyocytes of rats in ISO group were significantly higher than those in Control group(t = 25. 120 and18. 261,respectively,each P < 0. 01);While the expression levels of ANP and BNP mRNA in MPs group significantly reduced after incubation with 48 μg/mL MPs for 48 h compared with ISO group(t = 12. 110 and 3. 526,respectively,each P < 0. 05);The expression levels of CaMK Ⅱand p-CaMKⅡ in ISO group were significantly higher than those in Control group(t = 3. 278 and 4. 181,respectively,each P < 0. 05),while the expression of p-CaMK Ⅱ in MPs group decreased significantly(t = 5. 420,P < 0. 05);The calcium current density in ISO group was significantly higher than that in Control group(t = 15. 261,P < 0. 01),while that in MPs group was significantly lower than that in ISO group(t =6. 216,P < 0. 05).Conclusion MSC-MPs can significantly inhibit ISO-induced cardiomyocyte hypertrophy in rats,which is related to its down-regulation of cardiomyocyte CaMKⅡ and inhibition of L-type calcium channel.

Mechanism of Qifu Qiangxin Decoction Relieving Myocardial Damage in Heart Failure Mice with Heart-Kidney Yang Defi-ciency Syndrome / 浙江中医药大学学报

[Objective]To explore the mechanism of Qifu Qiangxin Decoction mitigating myocardial damage in heart failure(HF)mice with heart-kidney Yang deficiency syndrome.[Methods]Thirty C57BL/6 mice were randomly divided into Sham surgery group(Sham group),HF model(HF)group,low-dose Qifu Qiangxin Decoction(HF+QL)group,high-dose Qifu Qiangxin Decoction(HF+QH)group and western medicine[HF+angiotensin converting enzyme inhibitors(ACEI)]group,six in each group.In Sham group,the skin was cut open after anesthesia,the heart was exposed,the left anterior descending coronary artery was not in ligation,and then sutured.The rest were used to establish a mouse model of HF with heart-kidney Yang deficiency syndrome after myocardial infarction(MI)by ligating the left anterior descending coronary artery and swimming in cold water,then treated for 15 days.After treatment,the state of the mice was recorded,left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume(LVESV),ejection fraction(EF)and left ventricular fractional shortening(LVFS)were measured by echocardiography to evaluate cardiac function;hematoxylin-eosin(HE)staining was used to evaluate the morphological of myocardial tissue;the serum levels of B-syndrome natriuretic peptide(BNP)were measured by enzyme linked immunosorbent assay(ELISA);terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL)was used to detect cardiomyocyte apoptosis;Western blot was used to determine the expression levels of apoptosis related proteins,autophagy related proteins and adenosine monophosphate-activated protein kinase/mammalian target of rapamycin(AMPK/mTOR)signaling pathway related proteins in mice myocardial tissue.[Results]Qifu Qiangxin Decoction can relieve the symptoms of HF in mice.Compared with Sham group,EF and LVFS values of mice in HF group were significantly decreased,while LVEDV and LVESV were significantly increased(P＜0.01).Compared with HF group,EF and LVFS values in each group were significantly increased,while LVEDV and LVESV were significantly decreased(P＜0.01),moreover,HF+QH group had a better effect than that of HF+QL group.According to HE staining,extensive necrotic myocardial tissue was observed in HF group compared with Sham group,and ELISA showed a significant increase in BNP levels(P＜0.01).Compared with HF group,the pathological conditions of myocardial tissue were relieve in each group,and the level of BNP was also significantly reduced(P＜0.01).TUNEL staining and Western blot results showed that the level of apoptosis in HF group was significantly increased compared with Sham group(P＜0.05).Compared with HF group,the apoptosis level of the each group was significantly reduced(P＜0.05).Therefore,Qifu Qiangxin Decoction could significantly reduce the level of cardiomyocyte apoptosis.Western blot detection of autophagy-related proteins and AMPK/mTOR signaling pathway related proteins showed that Qifu Qiangxin Decoction could significantly enhance autophagy level and regulate AMPK/mTOR signaling pathway in a concentration-dependent manner.[Conclusion]Qifu Qiangxin Decoction can regulate AMPK/mTOR signaling pathway,inhibit cell apoptosis and induce autophagy,thus protecting cardiomyocytes and mitigating myocardial injury.

Hyperthyroidism Induces Ventricular Remodeling via Activating β-catenin/FoxO1 in Rat Cardiomyocytes / 中山大学学报(医学科学版)

ObjectiveTo explore how hyperthyroidism induces ventricular remodeling via activating β-catenin/FoxO1 in rat cardiomyocytes. MethodsHyperthyroidism-induced ventricular remodeling rat models were established by intraperitoneal injection of levothyroxine （T4） at 0.1 mg/kg for 30 days. β-catenin inhibitor MSAB （14 mg/kg） was administrated for 30 days. We used western blot to detect the expression of myocardial hypertrophy marker ANP， β-catenin and FoxO1； immunofluorescence to examine the expression and intracellular distribution of β-catenin and FoxO1. Hyperthyroidism-induced cardiomyocyte hypertrophy rat models were established by treatment of triiodothyronine （T3） into cultured primary neonatal rat cardiomyocytes for 24 hours. β-catenin siRNA （30 nmol/L） was used to down-regulate β-catenin expression in cardiomyocytes. Western blot and immunofluorescence were used to analyze the effects of β-catenin inhibition on the hyperthyroidism-induced cardiomyocyte hypertrophy. ResultsFollowing Wnt/β-catenin activation， β-catenin was found increased nuclear expression， to bind to the nuclear transcriptional factors and regulate the gene expression. β-catenin nuclear expression was significantly increased in the hyperthyroidism-induced ventricular remodeling rats， but no change was found in the expression of typical transcriptional factor TCF7l2. Our results revealed that inhibiting β-catenin by MSAB attenuated the hyperthyroidism-induced rat ventricular remodeling. Further analysis indicated that β-catenin/FoxO1 expression was significantly increased in hyperthyroidism-induced myocardial hypertrophy which could be attenuated by suppressing β-catenin/FoxO1 in cardiomyocytes. Conclusionsβ-catenin/FoxO1 is activated in hyperthyroidism-induced myocardial hypertrophy and β-catenin/FoxO1 inhibition attenuates hyperthyroidism-induced cardiomyocyte hypertrophy.

Mechanism of salvianolic acid B protecting H9C2 from OGD/R injury based on mitochondrial fission and fusion / 药学学报

This study aims to investigate the effect of salvianolic acid B (Sal B), the active ingredient of Salvia miltiorrhiza, on H9C2 cardiomyocytes injured by oxygen and glucose deprivation/reperfusion (OGD/R) through regulating mitochondrial fission and fusion. The process of myocardial ischemia-reperfusion injury was simulated by establishing OGD/R model. The cell proliferation and cytotoxicity detection kit (cell counting kit-8, CCK-8) was used to detect cell viability; the kit method was used to detect intracellular reactive oxygen species (ROS), total glutathione (t-GSH), nitric oxide (NO) content, protein expression levels of mitochondrial fission and fusion, apoptosis-related detection by Western blot. Mitochondrial permeability transition pore (MPTP) detection kit and Hoechst 33342 fluorescence was used to observe the opening level of MPTP, and molecular docking technology was used to determine the molecular target of Sal B. The results showed that relative to control group, OGD/R injury reduced cell viability, increased the content of ROS, decreased the content of t-GSH and NO. Furthermore, OGD/R injury increased the protein expression levels of dynamin-related protein 1 (Drp1), mitofusions 2 (Mfn2), Bcl-2 associated X protein (Bax) and cysteinyl aspartate specific proteinase 3 (caspase 3), and decreased the protein expression levels of Mfn1, increased MPTP opening level. Compared with the OGD/R group, it was observed that Sal B had a protective effect at concentrations ranging from 6.25 to 100 μmol·L-1. Sal B decreased the content of ROS, increased the content of t-GSH and NO, and Western blot showed that Sal B decreased the protein expression levels of Drp1, Mfn2, Bax and caspase 3, increased the protein expression level of Mfn1, and decreased the opening level of MPTP. In summary, Sal B may inhibit the opening of MPTP, reduce cell apoptosis and reduce OGD/R damage in H9C2 cells by regulating the balance of oxidation and anti-oxidation, mitochondrial fission and fusion, thereby providing a scientific basis for the use of Sal B in the treatment of myocardial ischemia reperfusion injury.

Hypoxic postconditioning protects myocardium by regulating autophagy in aging cardiomyocytes through piRNA-005854 / 中国组织工程研究

BACKGROUND:Ischemic postconditioning is one of the effective ways to reduce ischemia-reperfusion injury and has been more and more widely used in clinical practice in recent years,but its specific molecular mechanism has yet to be studied. OBJECTIVE:To investigate the role and mechanism of piRNA-005854 in the aging cardiomyocytes caused by hypoxic postconditioning. METHODS:In vitro,cardiomyocytes were administered 8 mg/mL D-galactose for 9 days to induce their aging.β-Galactosidase staining was used to observe the aging of cardiomyocytes.Senescent cells were treated with hypoxia/reoxygenation and hypoxic postconditioning.ELISA was utilized to detect changes in myocardial injury markers creatine kinase isoenzyme MB and lactate dehydrogenase levels.Western blot assay was applied to detect the expression changes of autophagy-related proteins LC3II,p62,ULK1 and phosphorylated ULK1 in aging cardiomyocytes.qRT-PCR was employed to determine the expression level of piRNA-005854.piRNA-005854 inhibitor and piRNA-005854 mimics were transferred into aging cardiomyocytes and followed with hypoxic postconditioning.Western blot assay was used to examine the expression of LC3II,p62,ULK1 and phosphorylated ULK1. RESULTS AND CONCLUSION:(1)D-galactose induced obvious senescence of cardiomyocytes 9 days later.(2)Compared with the normoxia group,creatine kinase isoenzyme MB and lactate dehydrogenase levels increased in the hypoxia/reoxygenation group(P<0.01);LC3 II/I expression was increased;p62 expression was decreased;ULK1 phosphorylation level was increased,and piRNA-005854 expression was increased(P<0.01).(3)Compared with the hypoxia/reoxygenation group,creatine kinase isoenzyme MB and lactate dehydrogenase levels significantly reduced in the hypoxic postconditioning group(P<0.01);LC3 II/I expression significantly decreased(P<0.05);p62 expression increased(P<0.01);ULK1 phosphorylation level decreased(P<0.05),and piRNA-005854 expression decreased(P<0.01).(4)After transfection of piRNA-005854 inhibitor,LC3II/I expression was decreased(P<0.01);the expression of p62 was increased significantly(P<0.05);the phosphorylation level of ULK1 was decreased significantly(P<0.01).After transfection of piRNA-005854 mimics,LC3II/I expression was increased significantly;the expression of p62 was decreased,and the phosphorylation level of ULK1 was increased significantly(P<0.01).(5)The results show that piRNA-005854-mediated reduction of ULK1-dependent autophagy level is a possible mechanism that hypoxic postconditioning exerts its protective effect on aging cardiomyocytes.

Myocardial patch:cell sources,improvement strategies,and optimal production methods / 中国组织工程研究

BACKGROUND:Myocardial patches are used as an effective way to repair damaged myocardium,and there is controversy over which cells to use to make myocardial patches and how to maximize the therapeutic effect of myocardial patches in vivo. OBJECTIVE:To find out the best way to make myocardial patches by overviewing the cellular sources of myocardial patches and strategies for perfecting them. METHODS:The first author searched PubMed and Web of Science databases by using"cell sheet,cell patch,cardiomyocytes,cardiac progenitor cells,fibroblasts,embryonic stem cell,mesenchymal stem cells"as English search terms,and searched CNKI and Wanfang databases by using"myocardial patch,biological 3D printing,myocardial"as Chinese search terms.After enrollment screening,94 articles were ultimately included in the result analysis. RESULTS AND CONCLUSION:(1)The cellular sources of myocardial patches are mainly divided into three categories:somatic cells,monoenergetic stem cells,and pluripotent stem cells,respectively.There are rich sources of cells for myocardial patches,but not all of them are suitable for making myocardial patches,e.g.,myocardial patches made from fibroblasts and skeletal myoblasts carry a risk of arrhythmogenicity,and mesenchymal stem cells have a short in vivo duration of action and ethical concerns.With the discovery of induced multifunctional stem cells,a reliable source of cells for making myocardial patches is available.(2)There are two methods of making myocardial patches.One is using cell sheet technology.The other is using biological 3D printing technology.Cell sheet technology can preserve the extracellular matrix components intact and can maximally mimic the cell growth ring in vivo.However,it is still difficult to obtain myocardial patches with three-dimensional structure by cell sheet technology.Biologicasl 3D printing technology,however,can be used to obtain myocardial patches with three-dimensional structures through computerized personalized design.(3)The strategies for perfecting myocardial patches mainly include:making myocardial patches after co-cultivation of multiple cells,improving the ink formulation and scaffold composition in biological 3D printing technology,improving the therapeutic effect of myocardial patches,suppressing immune rejection after transplantation,and perfecting the differentiation and cultivation protocols of stem cells.(4)There is no optimal cell source or method for making myocardial patches,and myocardial patches obtained from a particular cell or technique alone often do not achieve the desired therapeutic effect.Therefore,researchers need to choose the appropriate strategy for making myocardial patches based on the desired therapeutic effect before making them.

Regulation of N6-methyladenosine on non-coding RNAs in pathological cardiac remodeling / 中国组织工程研究

BACKGROUND:N6-methyladenosine(m6A)is a hot research topic in the mechanism of pathological cardiac remodeling and plays an important role in the development of cardiovascular diseases. OBJECTIVE:To summarize the possible mechanism by which m6A modification in non-coding RNAs regulates the main processes of pathological cardiac remodeling,such as pathological cardiac hypertrophy,cardiomyocyte death,myocardial fibrosis and vascular remodeling. METHODS:"m6A,non-coding RNA,pathological cardiac hypertrophy,cardiomyocyte apoptosis,cardiomyocyte pyroptosis,cardiomyocyte ferroptosis,myocardial fibrosis,vascular remodeling"were used as search terms in Chinese and English.Relevant literature from CNKI,PubMed and Web of Science databases published from January 1974 to April 2023 was retrieved,and finally 86 eligible articles were reviewed. RESULTS AND CONCLUSION:m6A modification is a highly dynamic and reversible modification.Pathological cardiac remodeling mainly involves pathological cardiac hypertrophy,cardiomyocyte apoptosis,cardiomyocyte pyroptosis,cardiomyocyte ferroptosis,myocardial fibrosis and vascular remodeling.m6A-related enzymes can regulate pathological cardiac remodeling processes through various non-coding RNAs and different signaling pathways,which can be used as a new potential intervention for cardiovascular diseases.In pathological cardiac remodeling,research on the regulatory relationship between m6A modification and non-coding RNAs is still in its infancy.With the development of epigenetics,m6A modification in non-coding RNAs is expected to have a new development in the regulation of pathological cardiac remodeling.

Application and mechanism of induced pluripotent stem cells in inherited heart disease models / 中国组织工程研究

BACKGROUND:Inherited heart disease has a high prevalence and mortality rate,but its pathogenesis has not yet been clarified.Although relevant animal models have been established to provide a foundation for the pathogenesis research of inherited heart disease,the value of these research results has been significantly reduced due to differences among species.Therefore,a new model is needed to explore its occurrence and development. OBJECTIVE:To review the current role of induced pluripotent stem cells in disease modeling and potential application prospects in various inherited heart diseases. METHODS:The first author searched the relevant articles published nearly 13 years in PubMed from January to March 2023.The search terms were"induced pluripotent stem cell,inherited heart disease,congenital heart disease".Finally,76 articles were included for analysis. RESULTS AND CONCLUSION:Since 2007,when induced pluripotent stem cells were induced from human somatic cells,many studies have been reported on disease-specific induced pluripotent stem cells.Due to the ability of disease-specific induced pluripotent stem cells to reproduce disease phenotypes,they are expected to become a new research tool for in vitro disease modeling,used to analyze pathogenesis and develop auxiliary drugs.In the research of cardiovascular genetic diseases,cardiomyocytes derived from patient-specific induced pluripotent stem cells contain gene mutations that are involved in cardiac dysplasia.Therefore,it can be used as a new tool to study the potential mechanisms of inherited heart disease.Up to now,induced pluripotent stem cells-derived cardiomyocytes have been widely used to study the molecular mechanisms of various genetic heart diseases,such as cardiac electrophysiological diseases,cardiomyopathy,and some syndromic inherited heart diseases.

Aerobic exercise upregulates the thioredoxin system and inhibits cardiomyocyte apoptosis in aging rats / 中国组织工程研究

BACKGROUND:Studies have shown that cardiomyocyte apoptosis is closely related to cardiac decompensation and the cardiac aging process.Appropriate exercise can alter heart pump function in patients with heart failure as well as attenuate aging-induced cardiomyocyte apoptosis,hypertrophy,and fibrotic damage. OBJECTIVE:To investigate the effects of long-term aerobic exercise on cardiomyocyte apoptosis and the thioredoxin system in aging rats. METHODS:Thirty-six male Sprague-Dawley rats were selected and divided into three age groups:3-month-old young group,9-month-old middle-aged group,and 18-month-old elderly group,with 12 rats in each group.Within each age group,rats were randomly assigned to sedentary and exercise subgroups(n=6 per group).The sedentary groups did not undergo any exercise intervention.The exercise groups were acclimated to a treadmill environment and subsequently subjected to treadmill exercise for 45 minutes per day,at a speed of 15 m/min,5 days per week for 10 weeks in total.At 24 hours after the final intervention,ELISA was employed to measure serum levels of cardiac troponin I and creatine kinase-MB in rats.TUNEL assay was utilized to detect cardiomyocyte apoptosis,while western blot assay was employed to assess the protein expression of Bax,Bcl-2,Caspase 3,thioredoxin-1,thioredoxin-2,thioredoxin reductase-1,thioredoxin reductase-2,thioredoxin-interacting protein,apoptosis signal-regulating kinase 1,and P38 mitogen-activated protein kinase in rat myocardial tissue. RESULTS AND CONCLUSION:Serum levels of cardiac troponin I and creatine kinase-MB in the elderly sedentary group were significantly higher than those in the young and middle-aged sedentary groups and elderly exercise group(P<0.01).Serum levels of cardiac troponin I and creatine kinase-MB in the elderly sedentary group were significantly higher than those in the young and middle-aged exercise groups and elderly exercise group(P<0.01).Positive apoptotic cells in rat myocardial tissue,along with increased protein expression of Bax and Caspase 3,exhibited an age-related upward trend,while Bcl-2 protein expression showed a declining trend.In comparison with the sedentary groups within each age category,the number of apoptotic cardiomyocytes and the expression of Bax and Caspase 3 proteins were reduced to different degrees,and the expression of Bcl-2 protein was increased to different degrees in the corresponding exercise groups.Compared with the young sedentary group,middle-aged sedentary group and elderly exercise group,elderly sedentary rats showed a significant decrease in the expression of myocardial thioredoxin 1,thioredoxin 2,thioredoxin reductase 1,and thioredoxin reductase 2 proteins(P<0.05,P<0.01).The expression of myocardial thioredoxin 1,thioredoxin 2,and thioredoxin reductase 2 proteins was lower in the elderly exercise group than in the young exercise group(P<0.05,P<0.01),while the expression of thioredoxin reductase 1 and thioredoxin reductase 2 proteins was lower in the elderly exercise group than in the middle-aged exercise group(P<0.01).The protein expression of thioredoxin-interacting protein,apoptosis signal-regulating kinase 1,and P38 mitogen-activated protein kinase in rat myocardium was significantly higher in the elderly sedentary group than the young sedentary group,middle-aged sedentary group and elderly exercise group(P<0.01).The protein expression of thioredoxin-interacting protein,apoptosis signal-regulating kinase 1,and P38 mitogen-activated protein kinase in rat myocardium was significantly higher in the elderly exercise group than the young exercise group and middle-aged exercise group(P<0.01).To conclude,aerobic exercise may enhance the anti-apoptotic effects of thioredoxin by down-regulating the expression of thioredoxin-interacting protein in aging rat hearts,leading to the downregulation of apoptosis signal-regulated kinase 1 and P38 mitogen-activated kinase protein,thereby alleviating myocardial cell apoptosis in aging rat hearts.

Effect of sodium fluoride on myocardial damage by regulating apoptosis through JNK signaling pathway / 环境与职业医学

Background It has been found that fluoride may cause cardiomyocyte damage. c-Jun N-terminal kinases (JNK) signaling pathway plays an important role in apoptosis, but its role in fluorosis-induced cardiomyocyte damage is still unknown yet. Objective To explore the toxic effect of sodium fluoride (NaF) on H9c2 cardiomyocytes of rats and whether NaF affects cardiomyocyte apoptosis through the JNK signaling pathway. Methods According to the concentrations of sodium fluoride and whether sp600125 (JNK inhibitor) was added, cardiomyocytes of rats were divided into six groups, including control group, SP600125 group (SP group), 0.24, 0.48, and 0.96 mmol·L−1 NaF groups, and 0.96 mmol·L−1 NaF+SP600125 group (NaF+SP group). Cardiomyocytes exposed to NaF for 24 h were observed using a fluorescence inverted microscope. The changes of cell viability at 24, 48, and 72 h after the treatment were detected by CCK-8 method. The levels of reactive oxygen species (ROS) at 24 h after the treatment in H9c2 cardiomyocytes were determined by fluorescent probe method. The expression levels of Bcl-2, Bax, Caspase-3, and JNK mRNA at 24 h after the treatment were detected by real-time PCR. The protein expression levels of Bcl-2, Bax, Caspase-3, and p-JNK at 24 h after the treatment were detected by Western blotting. Results Compared with the control group, after being exposed to 0.48 and 0.96 mmol·L−1 NaF for 24 h, the cell growth density decreased. With the increase of NaF concentration, rounded cells and some suspended dead cells appeared. At 24h after exposure to NaF, the cell viability of the 0.48 and 0.96 mmol·L−1 NaF groups decreased compared with the control group (P<0.05). At 48h and 72h after exposure to NaF, the cell viability levels of the NaF treated groups were significantly lower than that of the control group (P<0.05). After NaF exposure for 24 h, compared with the control group, the intracellular ROS levels were increased (P<0.05); the mRNA expression levels of Bcl-2 were decreased to varying degrees, especially in the 0.48 and 0.96 mmol·L−1 NaF groups (P<0.05); the mRNA expression levels of Bax, Caspase-3, and JNK were increased (P<0.05); the protein expression levels of Bcl-2 were reduced (P<0.05); the protein expression levels of Bax, Caspase-3, and p-JNK were elevated (P<0.05). Compared with the 0.96 mmol·L−1 NaF group, the cell viability of the NaF+SP group was increased, the intracellular ROS level was decreased, the mRNA expression levels of Bax, Caspase-3, and JNK were decreased, the protein expression level of Bcl-2 was increased, and the protein expression levels of Bax, Caspase-3, and p-JNK were decreased (P<0.05); the expression level of Bcl-2 mRNA had a rising trend but showed no statistical significance (P>0.05). Conclusion Cardiomyocyte damage after excessive fluoride exposure may result from fluoride inducing excessive ROS production in cardiomyocytes, which may activate the JNK signaling pathway and induce cardiomyocyte apoptosis.

MicroRNA-22-3p Regulates the Expression of Kruppel-like Factor 6 to Affect the Cardiomyocyte-like Differentiation of Bone Marrow Mesenchymal Stem Cell / 中国医学科学院学报

Objective To explore the effect of microRNA-22-3p (miR-22-3p) regulating the expression of Kruppel-like factor 6 (KLF6) on the cardiomyocyte-like differentiation of bone marrow mesenchymal stem cell (BMSC). Methods Rat BMSC was isolated and cultured,and the third-generation BMSC was divided into a control group,a 5-azacytidine(5-AZA)group,a mimics-NC group,a miR-22-3p mimics group,a miR-22-3p mimics+pcDNA group,and a miR-22-3p mimics+pcDNA-KLF6 group.Real-time fluorescent quantitative PCR (qRT-PCR) was carried out to determine the expression of miR-22-3p and KLF6 in cells.Immunofluorescence staining was employed to detect the expression of Desmin,cardiac troponin T (cTnT),and connexin 43 (Cx43).Western blotting was employed to determine the protein levels of cTnT,Cx43,Desmin,and KLF6,and flow cytometry to detect the apoptosis of BMSC.The targeting relationship between miR-22-3p and KLF6 was analyzed by dual luciferase reporter gene assay. Results Compared with the control group,5-AZA up-regulated the expression of miR-22-3p (q=7.971,P<0.001),Desmin (q=7.876,P<0.001),cTnT (q=10.272,P<0.001),and Cx43 (q=6.256,P<0.001),increased the apoptosis rate of BMSC (q=12.708,P<0.001),and down-regulated the mRNA (q=20.850,P<0.001) and protein (q=11.080,P<0.001) levels of KLF6.Compared with the 5-AZA group and the mimics-NC group,miR-22-3p mimics up-regulated the expression of miR-22-3p (q=3.591,P<0.001;q=11.650,P<0.001),Desmin (q=5.975,P<0.001;q=13.579,P<0.001),cTnT (q=7.133,P<0.001;q=17.548,P<0.001),and Cx43 (q=4.571,P=0.037;q=11.068,P<0.001),and down-regulated the mRNA (q=7.384,P<0.001;q=28.234,P<0.001) and protein (q=4.594,P=0.036;q=15.945,P<0.001) levels of KLF6.The apoptosis rate of miR-22-3p mimics group was lower than that of 5-AZA group (q=8.216,P<0.001).Compared with the miR-22-3p mimics+pcDNA group,miR-22-3p mimics+pcDNA-KLF6 up-regulated the mRNA(q=23.891,P<0.001) and protein(q=13.378,P<0.001)levels of KLF6,down-regulated the expression of Desmin (q=9.505,P<0.001),cTnT (q=10.985,P<0.001),and Cx43 (q=8.301,P<0.001),and increased the apoptosis rate (q=4.713,P=0.029).The dual luciferase reporter gene experiment demonstrated that KLF6 was a potential target gene of miR-22-3p. Conclusion MiR-22-3p promotes cardiomyocyte-like differentiation of BMSC by inhibiting the expression of KLF6.

Renewal of embryonic and neonatal-derived cardiac-resident macrophages in response to environmental cues abrogated their potential to promote cardiomyocyte proliferation via Jagged-1-Notch1

Cardiac-resident macrophages (CRMs) play important roles in homeostasis, cardiac function, and remodeling. Although CRMs play critical roles in cardiac regeneration of neonatal mice, their roles are yet to be fully elucidated. Therefore, this study aimed to investigate the dynamic changes of CRMs during cardiac ontogeny and analyze the phenotypic and functional properties of CRMs in the promotion of cardiac regeneration. During mouse cardiac ontogeny, four CRM subsets exist successively: CX3CR1+CCR2-Ly6C-MHCII- (MP1), CX3CR1lowCCR2lowLy6C-MHCII- (MP2), CX3CR1-CCR2+Ly6C+MHCII- (MP3), and CX3CR1+CCR2-Ly6C-MHCII+ (MP4). MP1 cluster has different derivations (yolk sac, fetal liver, and bone marrow) and multiple functions population. Embryonic and neonatal-derived-MP1 directly promoted cardiomyocyte proliferation through Jagged-1-Notch1 axis and significantly ameliorated cardiac injury following myocardial infarction. MP2/3 subsets could survive throughout adulthood. MP4, the main population in adult mouse hearts, contributed to inflammation. During ontogeny, MP1 can convert into MP4 triggered by changes in the cellular redox state. These findings delineate the evolutionary dynamics of CRMs under physiological conditions and found direct evidence that embryonic and neonatal-derived CRMs regulate cardiomyocyte proliferation. Our findings also shed light on cardiac repair following injury.

Effect of asiaticoside on OGD/R induced injury of H9C2 cardiomyocytes based on PI3K/Akt/Beclin-1 signaling pathway / 药学学报

In order to investigate the effects of asiaticoside (Ass) on H9C2 cardiomyocytes, the present study examined the potential intervention of Ass on the proliferation and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/Bcl-2 homology domain protein (Beclin-1) signaling pathway in H9C2 cardiomyocytes following oxygen and glucose deprivation/reperfusion (OGD/R) injury. H9C2 cardiomyocytes were selected as the research objects, and the activity of H9C2 was detected by cell counting kit-8 (CCK-8). H9C2 cells were divided into control group, OGD/R group, Ass low concentration group (10 μmol·L-1), Ass high concentration group (80 μmol·L-1) and Ass high concentration + chloroquine group (80 μmol·L-1 + 50 μmol·L-1). The control group was cultured under normal conditions, and the other groups were treated with oxygen and glucose deprivation for 4 h and reperfusion for 2 h. The activity and content of aspartic aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) in the supernatant of H9C2 cardiomyocytes were detected by enzyme-linked immunosorbent assay. Autophagy staining assay kit with monodansylcadaverine (MDC) method to observe cellular autophagy; molecular docking technique to identify the molecular targets of Ass. Immunofluorescence was used to observe the effect of the drug on cell number. The expression levels of PI3K, Akt, selective autophagy adaptor protein (P62) and Beclin-1 were detected by Western blot. Compared with OGD/R group, Ass group had a protective effect from 10-80 μmol·L-1, and the activities and contents of AST, LDH and CK were decreased. The protein expression levels of PI3K, Akt, P62 and Beclin-1 were decreased. Compared with the administration group, the activities and contents of AST, LDH and CK in Ass high-concentration + chloroquine group were significantly decreased, and the protein expression levels of PI3K, Akt, Beclin-1 and P62 were significantly decreased. Immunofluorescence showed that the inhibitor group and each administration group had different degrees of protective effect compared with the model group. Asiaticoside can reduce the injury of H9C2 cardiomyocyte induced by OGD/R, reduce the content of AST, LDH and CK, reduce the expression level of P62 protein, and reduce autophagy, which may be closely related to the inhibition of PI3K/Akt/Beclin-1 signaling pathway activation.

Cardiomyocyte Energy Metabolism in Mammalian Cardiac Regeneration / 中山大学学报(医学科学版)

Cardiovascular disease， such as coronary heart disease and acute myocardial infarction， is a leading cause of death globally. Due to the limited proliferative and regenerative capacity of adult mammalian cardiomyocytes （CMs）， any of the current therapies cannot reverse the massive loss of CMs and subsequent fibrosis resulting from cardiac injury. Mammals mainly rely on glycolysis in the embryonic stage and fatty acid oxidation after birth for energy production. Recent reports have indicated that this metabolic pattern switch is closely related to the loss of CM proliferation. In this review， we summarize the biological characteristics of CMs and advances in heart regeneration， meanwhile shed light on the important role of CMs energy metabolism in cardiac regeneration.

Two new isoquinoline alkaloids from Corydalis hendersonii / 中国中药杂志

Corydalis hendersonii(CH) is a Tibetan folk medicine with the functions of clearing heat, detoxifying, cooling blood, checking diarrhea, and lowering blood pressure. It is often used to treat high altitude polycythemia, vasculitis, peptic ulcer, and diarrhea. Nine compounds were separated from the ethanol extract of CH by silica gel, ODS, Sephadex LH-20 chromatography and semi-preparative HPLC. Their structures were identified as hendersine H(1),hendersine I(2), dehydrocheilanthifoline(3), protopine(4), izmirine(5), 6,7-methylenedioxy-1(2H)-isoquinolinone(6), icariside D_2(7), ethyl 4-(β-D-glucopyranosyloxy)-3-methoxybenzoate(8), 3-hydroxy-4-methoxybenzoic acid(9), respectively, by the spectroscopic data analysis and comparison with those in the literature. Among them, compounds 1 and 2 are new isoquinoline alkaloids, and compounds 7-9 are reported the first time for Corydalis. The hypoglycemic model of H9c2 cardiomyocytes and the inflammatory model of H9c2 cardiomyocytes induced by conditional supernatant were employed to determine the activities of the above compounds. The results showed that 20 μmol·L~(-1) compound 1 had a protective effect on H9c2 cardiomyocytes and 10 μmol·L~(-1) compounds 4 and 5 inhibited H9c2 cardiomyocyte inflammation induced by conditional supernatant.

Single-nucleus transcriptomics reveals a gatekeeper role for FOXP1 in primate cardiac aging

Aging poses a major risk factor for cardiovascular diseases, the leading cause of death in the aged population. However, the cell type-specific changes underlying cardiac aging are far from being clear. Here, we performed single-nucleus RNA-sequencing analysis of left ventricles from young and aged cynomolgus monkeys to define cell composition changes and transcriptomic alterations across different cell types associated with age. We found that aged cardiomyocytes underwent a dramatic loss in cell numbers and profound fluctuations in transcriptional profiles. Via transcription regulatory network analysis, we identified FOXP1, a core transcription factor in organ development, as a key downregulated factor in aged cardiomyocytes, concomitant with the dysregulation of FOXP1 target genes associated with heart function and cardiac diseases. Consistently, the deficiency of FOXP1 led to hypertrophic and senescent phenotypes in human embryonic stem cell-derived cardiomyocytes. Altogether, our findings depict the cellular and molecular landscape of ventricular aging at the single-cell resolution, and identify drivers for primate cardiac aging and potential targets for intervention against cardiac aging and associated diseases.

Study on the role of indole sulfate in inducing myocardial hypertrophy and fibrosis through organic anion transporter-3 and oxidative stress / 中国医师杂志

Objective:To investigate the role of indoxyl sulfate (IS) in myocardial hypertrophy and fibrosis through organic anion transporter-3 (OAT-3) and oxidative stress in H9C2 cells.Methods:Rat myocardial cells (H9C2) were cultured and divided into four groups: Control group, IS group, siRNA negative control group (siOAT-3), and siOAT-3+ IS group. The control group was cultured routinely without IS stimulation. The IS group was stimulated with 250 μmol IS. The siRNA negative control group was transfected with 20 nmol/L OAT-3 siRNA, and the siOAT-3+ IS group was transfected with OAT-3 siRNA 48 hours later, then stimulated with IS for 24 hours. Real-time polymerase chain reaction (RT-PCR) was used to detect and analyze the mRNA expression levels of OAT-3, NADPH oxidase-4 (Nox-4), antioxidant proteins [nuclear factor E2 related factor 2 (Nrf-2), heme oxygenase 1 (HO-1)], myocardial hypertrophy markers [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), β-myosin heavy chain gene (β-MHC)], and fibrosis markers [transforming growth factor β1 (TGF-β1), Smad homologous protein 3 (Smad-3), collagen type Ⅰ (Collagen Ⅰ)] in each group. H9C2 cells were further divided into three groups: Control group, IS group, and N-acetylcysteine (NAC) group. The NAC group was pre-treated with the antioxidant NAC before stimulation with 250 μmol IS for 24 hours. RT-PCR was used to detect the mRNA expression levels of the above indicators.Results:The mRNA expression level of OAT-3 in the IS group was significantly higher than that in the control group, while the mRNA expression levels of OAT-3 in the siOAT-3 group and the siOAT-3+ IS group were significantly lower than those in the IS group (all P<0.001). Compared with the Control group, the mRNA relative expression levels of Nox-4, ANP, BNP, β-MHC, TGF-β1, Smad-3, and Collagen Ⅰ in H9C2 cells of the IS group were significantly increased (all P<0.001), while the mRNA expression levels of Nrf-2 and HO-1 were significantly decreased (all P<0.001). Compared with the IS group, the mRNA relative expression levels of Nox-4, ANP, BNP, β-MHC, TGF-β1, Smad-3, and Collagen Ⅰ in H9C2 cells of the siOAT-3 group and the siOAT-3+ IS group were significantly lower (all P<0.001), while the mRNA expression levels of Nrf-2 and HO-1 were significantly increased (all P<0.001). Pre-treatment with NAC significantly inhibited the high expression of Nox-4, ANP, BNP, β-MHC, TGF-β1, Smad-3, and Collagen Ⅰ mRNA induced by IS (all P<0.001), while significantly increasing the mRNA expression levels of Nrf-2 and HO-1 (all P<0.01). Conclusions:IS promotes myocardial hypertrophy and fibrotic factor overexpression in H9C2 cells through OAT-3 and oxidative stress.

Chemical constituents from Senecionis Scandentis Hebra and their protective effects on cardiomyocyte / 中成药

AIM To study the chemical constituents from Senecionis Scandentis Hebra and their protective effects on cardiomyocyte.METHODS The 95%ethanol extract of S.scandens was isolated and purified by silica gel,Sephadex LH-20,MCI and semi-preparative HPLC,then the structures of obtained compounds were identified by physicochemical properties and spectral data.The protective effects of all compounds were tested on myocardial cells H9c2.RESULTS Seven compounds were isolated and identified as(R)-seneterniol(1),(1S,10S),(4S,5S)-germacrone-1(10),4-diepoxide(2),12-hydroxy-cyperone(3),urcumenone(4),isopterchiayione(5),curcumadione(6),gibberodione(7).The survival rates of H9c2 cells in compounds 2-3 and 5 were(75.2±0.54)%,(66.4±0.79)%,(59.7±0.91)%,respectively.CONCLUSION Compound 1 is a new compound.Compounds 2-7 are isolated from this plant for the first time.Compounds 2-3,5 have protective effects on cardiomyocyte.

SUMO1 regulates post-infarct cardiac repair based on cellular heterogeneity / 药物分析学报

Small ubiquitin-related modifier(SUMOylation)is a dynamic post-translational modification that maintains cardiac function and can protect against a hypertrophic response to cardiac pressure overload.However,the function of SUMOylation after myocardial infarction(MI)and the molecular details of heart cell responses to SUMO1 deficiency have not been determined.In this study,we demonstrated that SUMO1 protein was inconsistently abundant in different cell types and heart regions after MI.However,SUMO1 knockout significantly exacerbated systolic dysfunction and infarct size after myocardial injury.Single-nucleus RNA sequencing revealed the differential role of SUMO1 in regulating heart cells.Among cardiomyocytes,SUMO1 deletion increased the Nppa+Nppb+Ankrd1+cardiomyocyte subcluster pro-portion after MI.In addition,the conversion of fibroblasts to myofibroblasts subclusters was inhibited in SUMO1 knockout mice.Importantly,SUMO1 loss promoted proliferation of endothelial cell subsets with the ability to reconstitute neovascularization and expressed angiogenesis-related genes.Computational analysis of ligand/receptor interactions suggested putative pathways that mediate cardiomyocytes to endothelial cell communication in the myocardium.Mice preinjected with cardiomyocyte-specific AAV-SUMO1,but not the endothelial cell-specific form,and exhibited ameliorated cardiac remodeling following MI.Collectively,our results identified the role of SUMO1 in cardiomyocytes,fibroblasts,and endothelial cells after Ml.These findings provide new insights into SUMO1 involvement in the patho-genesis of MI and reveal novel therapeutic targets.

Formononetin regulates dilated cardiomyopathy-mediated heart failure in rats via HSP90/AKT cardiomyocyte apoptosis and mechanism / 西安交通大学学报(医学版)

【Objective】 To investigate the effects of formononetin (FMN) on cardiomyocyte apoptosis and HSP90/AKT in rats with dilated cardiomyopathy-mediated heart failure. 【Methods】 Echocardiography, ELISA, histological staining, and TUNEL staining were used to observe the protective effect of different doses of FMN on dilated cardiomyopathy-mediated heart failure in rats and the apoptosis of cardiomyocytes. The potential targets of formononetin on dilated cardiomyopathy-mediated heart failure were obtained from TCMSP, DisGeNet, GeneCards, and other databases, the key targets were obtained according to the protein-protein interaction (PPI) network, and the key targets were verified by molecular docking. Western blotting was used to further verify the regulatory role of key targets in the treatment of dilated cardiomyopathy-mediated heart failure with formononetin. 【Results】 Formononetin could reduce the levels of LVIDS, LVIDD, NT-pro BNP, cTn-T, CK, CK-MB, and LDH in rats with dilated cardiomyopathy-mediated heart failure, increase the levels of EF and FS, and reduce the apoptosis of cardiomyocytes. FMN had a strong binding effect on 10 key targets (AKT1, HSP90AA1, CASP3, MAPK1, MMP9, SRC, ALB, HRAS, IGF1, and EGFR) screened by network pharmacology, with HSP90AA1 and AKT1 having the strongest binding effect. Formononetin decreased the expression of HSP90, AKT and downstream CASP3 protein, but increased the expression of p-AKT in myocardial tissue. 【Conclusion】 Formononetin may inhibit the expression of HSP90, promote phosphorylation of AKT to p-AKT, and inhibit the expression of CASP3, thereby reducing the apoptosis of cardiomyocytes and improving myocardial tissue damage, so as to achieve the purpose of treating dilated cardiomyopathy-mediated heart failure.