Objective:To investigate the biological role and molecular mechanism of checkpoint kinase 1 (CHK1) in delaying cardiac aging in mice.Methods:In vitro, a senescence model of H9C2 cells (a cardiomyocyte line) was induced using H 2O 2. A control group (without H 2O 2 treatment) and three H 2O 2-treated groups (at concentrations of 10, 30, and 50 μmol/L) were set up. The CCK-8 assay was used to evaluate the proliferative activity of cells in each group; Western blot analysis was employed to detect the expression level of CHK1; and quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the messenger RNA (mRNA) expression levels of P16 and interleukin-1β (IL-1β). In vivo, C57BL/6 wild-type mice aged 2 months ( n=15) and 24 months ( n=40), as well as myocardial-specific CHK1-overexpressing (CHK1-TG) mice aged 2 months ( n=15) and 24 months ( n=40), were selected. The mice were divided into four groups based on age and genotype: 2-month-old wild-type (WT-2M), 24-month-old wild-type (WT-24M), 2-month-old CHK1-TG (CHK1-TG-2M), and 24-month-old CHK1-TG (CHK1-TG-24M). Echocardiography was used to evaluate cardiac function of mice in the WT-24M and CHK1-TG-24M groups. Western blot analysis was conducted to measure the protein expression levels of CHK1, total Ras-related protein 1 (Rap1), NADPH oxidase 4 (Nox4), and Rap1-guanosine triphosphate (Rap1-GTP, the active form of Rap1) in the cardiac tissue of mice in each group. qRT-PCR was used to detect the messenger RNA (mRNA) expression levels of CHK1, collagen type Ⅰ (Coll1), matrix metalloproteinase-2 (Mmp2), alpha-smooth muscle actin (α-SMA), P53, P21, P16, thioredoxin 1 (Trx1), thioredoxin reductase (TrxR), glutathione recluctase (GR), Rap1, and Nox4. Immunofluorescence staining was employed to determine the protein expression levels of P53, P21, and P16, as well as the proportion of histone H2AX phosphorylation-positive cells. Dihydroethidium (DHE) staining was used to detect the relative intensity of DHE. Wheat germ agglutinin staining, HE staining, Masson staining and Sirius red staining were applied to measure the cross-sectional area of cardiomyocytes, cardiac morphology, and myocardial fibrosis area. Mice in the WT-24M and CHK1-TG-24M groups were intraperitoneally injected with the Rap1 activity inhibitor GGTI298 (25 μmol/kg). After injection, the oxidative stress damage in the cardiac tissue of the mice was detected, along with the mRNA expression levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P16, P21, and P53). Results:A concentration of 30 μmol/L was determined as the optimal concentration for establishing an H 2O 2-induced senescence model of myocardial cells in vitro. The expression level of CHK1 in H9C2 cells of the 30 μmol/L H 2O 2 group was lower than that in the control group ( P<0.05). Echocardiographic examination showed that the left ventricular ejection fraction ((61.08±1.13)% vs. (52.55±2.02)%) and fractional shortening ((31.80±1.27)% vs. (25.18±1.59)%) of mice in the CHK1-TG-24M group were higher than those in the WT-24M group (both P<0.05). qRT-PCR and Western blot analysis revealed that, compared with the WT-24M group, mice in CHK1-TG-24M group had higher expression levels of CHK1 and its mRNA, lower expression levels of Nox4 and its mRNA, and higher expression level of Rap1-guanosine triphosphate (Rap1-GTP) (all P<0.05). However, there were no statistically significant differences in the total expression level of Rap1 and its mRNA between the two groups (both P>0.05). In addition, the mRNA expression levels of Coll1, Mmp2, and α-SMA in myocardial tissue of mice in the CHK1-TG-24M group were lower than those in the WT-24M group (all P<0.05). Immunofluorescence staining results showed that the expression levels of P53, P21, and P16 proteins, as well as the proportion of phosphorylated histone H2AX-positive cells in myocardial tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). qRT-PCR further confirmed that the mRNA expression levels of the above-mentioned proteins in cardiac tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). DHE staining results indicated that the relative intensity of DHE in cardiac tissue of mice in the CHK1-TG-24M group was lower than that in the WT-24M group ( P<0.05). Meanwhile, the left ventricular internal diameter, cross-sectional area of cardiomyocytes, and myocardial fibrosis area of mice in the CHK1-TG-24M group were all smaller than those in the WT-24M group (all P<0.05). Furthermore, the degree of DNA damage in cardiac tissue as well as the mRNA levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P53, P21, P16) in mice of the WT-24M+GGTI298 group were higher than those in the WT-24M group and the CHK1-TG-24M+GGTI298 group (all P<0.05). Conclusion:CHK1 alleviates oxidative stress-induced damage in mouse cardiomyocytes by activating the Rap1/Nox4 signaling pathway, thereby delaying cardiac aging in mice.

Twelve derivatives of asiatic acid were synthesized through acylation, alkylation, oxidative dehydrogenation and other reactions using asiatic acid from usoxane-type pentacyclic triterpenoids as the parent compound. Their structures were confirmed by 1H NMR and 13C NMR, and determined to be novel compounds never reported in literature. Through the MTT method, high-expression human cancer cells (A549 and SGC-7901) were selected for a preliminary in vitro anti-tumor activity study on these compounds. Among them, the IC50 of compound I1 were 11.39 and 9.08 μmol/L respectively, and those of compound I2 were 12.64 and 9.15 μmol/L respectively, which were close to those of sorafenib, a common drug for clinical use. The experimental results show that the synthesized asiatic acid derivatives have certain anti-proliferative effects on the two types of human cancer cells, A549 and SGC-7901, significantly higher than those of asiatic acid. Compounds I1 and I2 show quite strong anti-proliferative effects on human cancer cells A549 and SGC-7901.

Objective:To investigate the effect of DEAD-box helicase (DDX) 21 on myocardial ischemia-reperfusion (I/R) injury and its potential mechanisms.Methods:In vivo, adult male Bama pigs and C57BL/6J mice were used to establish a myocardial I/R injury model by ligating the left anterior descending coronary artery, with sham-operated groups set as controls. The expression of DDX21 in myocardium after I/R injury was assessed by quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence staining. Following the establishment of the myocardial I/R injury model in mice, AAV9 vectors with cardiac-specific expression were injected in situ into the peri-infarct region (The I/R+DDX21 group, I/R+negative control (NC) group, I/R+sh-NC group and I/R+sh-DDX21 group were injected with AAV9:cTnT-DDX21, AAV9:cTnT-NC, AAV9:cTnT-sh-NC and AAV9:cTnT-sh-DDX21, respectively). Additionally, the I/R+A-485 group received intraperitoneal injections of the cAMP response element-binding protein (CREB) binding protein inhibitor A-485, while the I/R+PBS group was injected with an equivalent volume of phosphate-buffered saline (PBS) as the control. Echocardiography was performed on postoperative days 1 and 28 to evaluate cardiac function (left ventricular ejection fraction and fractional shortening). At 28 days post-surgery, mice were euthanized and heart tissues were harvested for histological sectioning. Myocardial fibrosis was evaluated using Masson′s trichrome staining. In vitro, primary cardiomyocytes were isolated from neonatal day 1 C57BL/6J mice using enzymatic digestion method. Cardiomyocytes were transfected with plasmids or small interfering RNA (siRNA). The cardiomyocytes transfected with DDX21-siRNA were assigned to the siDDX21 group, those transfected with the DDX21 plasmid were assigned to the DDX21 group, and those transfected with the corresponding empty plasmid or siRNA were assigned to the NC group. Additionally, cardiomyocytes were treated with A-485 (A-485 group) or PBS (PBS group). An oxygen-glucose deprivation/reoxygenation (OGD/R) model was used to simulate cellular injury. Transcriptome sequencing was performed to identify downstream mechanisms of DDX21. Differential gene expression analysis was conducted using software such as DESeq2, and alternative splicing events in the mRNA transcriptome were analyzed using rMATS software. Mitochondrial superoxide, mitochondrial membrane potential, ATP content, and mitochondrial respiratory chain complex enzyme activity in cardiomyocytes were detected using immunofluorescence staining and commercial assay kits. The oxidative phosphorylation level of the cells was assessed by the Seahorse extracellular flux analyzer. Acetylated DDX21 levels were measured using co-immunoprecipitation and Western blot assays.Results:The expression levels of DDX21 in myocardium from the Bama pigs and mice in the I/R injury model were significantly higher than those in the sham group (all P<0.001). Echocardiographic results showed that at 28 days post-surgery, compared to the I/R+NC group, the I/R+DDX21 group exhibited higher left ventricular ejection fraction and fractional shortening, while the I/R+sh-DDX21 group showed lower values; Masson staining results demonstrated that, compared to the I/R+NC group, the myocardial fibrosis area in the I/R+DDX21 group was significantly reduced, whereas it was significantly increased in the I/R+sh-DDX21 group (all P<0.001). Transcriptomic sequencing results suggested that DDX21 may influence myocardial injury by regulating mitochondrial metabolic activity. In vitro, compared to the OGD/R+NC group, the OGD/R+DDX21 group exhibited lower mitochondrial superoxide levels, higher polymer/monomer ratio, maximal oxygen consumption, reserve capacity, and ATP content. In contrast, the OGD/R+siDDX21 group showed the opposite results, with reduced activity of mitochondrial respiratory chain complex V (all P<0.05). Mechanistically, rMATS software and other analyses indicated that knockdown of DDX21 affected the alternative 3′ splicing sites of ATP5J precursor mRNA, inhibiting the splicing of certain exonic sequences. Overexpression of DDX21 upregulated both mRNA and protein levels of ATP5J. Co-immunoprecipitation experiments showed that, compared to the PBS group, acetylated DDX21 levels were reduced in the A-485 group. Further in vivo experiments showed that, compared to the I/R+PBS group, the I/R+A-485 group exhibited higher left ventricular ejection fraction and fractional shortening, and a lower proportion of left ventricular fibrosis (all P<0.001). Conclusions:DDX21 improves cardiomyocyte energy metabolism and alleviates I/R injury by regulating the alternative splicing of ATP5J. A-485 holds potential as a novel small molecule candidate for the treatment of myocardial injury.

Objective:To investigate the effect of DEAD-box helicase (DDX) 21 on myocardial ischemia-reperfusion (I/R) injury and its potential mechanisms.Methods:In vivo, adult male Bama pigs and C57BL/6J mice were used to establish a myocardial I/R injury model by ligating the left anterior descending coronary artery, with sham-operated groups set as controls. The expression of DDX21 in myocardium after I/R injury was assessed by quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence staining. Following the establishment of the myocardial I/R injury model in mice, AAV9 vectors with cardiac-specific expression were injected in situ into the peri-infarct region (The I/R+DDX21 group, I/R+negative control (NC) group, I/R+sh-NC group and I/R+sh-DDX21 group were injected with AAV9:cTnT-DDX21, AAV9:cTnT-NC, AAV9:cTnT-sh-NC and AAV9:cTnT-sh-DDX21, respectively). Additionally, the I/R+A-485 group received intraperitoneal injections of the cAMP response element-binding protein (CREB) binding protein inhibitor A-485, while the I/R+PBS group was injected with an equivalent volume of phosphate-buffered saline (PBS) as the control. Echocardiography was performed on postoperative days 1 and 28 to evaluate cardiac function (left ventricular ejection fraction and fractional shortening). At 28 days post-surgery, mice were euthanized and heart tissues were harvested for histological sectioning. Myocardial fibrosis was evaluated using Masson′s trichrome staining. In vitro, primary cardiomyocytes were isolated from neonatal day 1 C57BL/6J mice using enzymatic digestion method. Cardiomyocytes were transfected with plasmids or small interfering RNA (siRNA). The cardiomyocytes transfected with DDX21-siRNA were assigned to the siDDX21 group, those transfected with the DDX21 plasmid were assigned to the DDX21 group, and those transfected with the corresponding empty plasmid or siRNA were assigned to the NC group. Additionally, cardiomyocytes were treated with A-485 (A-485 group) or PBS (PBS group). An oxygen-glucose deprivation/reoxygenation (OGD/R) model was used to simulate cellular injury. Transcriptome sequencing was performed to identify downstream mechanisms of DDX21. Differential gene expression analysis was conducted using software such as DESeq2, and alternative splicing events in the mRNA transcriptome were analyzed using rMATS software. Mitochondrial superoxide, mitochondrial membrane potential, ATP content, and mitochondrial respiratory chain complex enzyme activity in cardiomyocytes were detected using immunofluorescence staining and commercial assay kits. The oxidative phosphorylation level of the cells was assessed by the Seahorse extracellular flux analyzer. Acetylated DDX21 levels were measured using co-immunoprecipitation and Western blot assays.Results:The expression levels of DDX21 in myocardium from the Bama pigs and mice in the I/R injury model were significantly higher than those in the sham group (all P<0.001). Echocardiographic results showed that at 28 days post-surgery, compared to the I/R+NC group, the I/R+DDX21 group exhibited higher left ventricular ejection fraction and fractional shortening, while the I/R+sh-DDX21 group showed lower values; Masson staining results demonstrated that, compared to the I/R+NC group, the myocardial fibrosis area in the I/R+DDX21 group was significantly reduced, whereas it was significantly increased in the I/R+sh-DDX21 group (all P<0.001). Transcriptomic sequencing results suggested that DDX21 may influence myocardial injury by regulating mitochondrial metabolic activity. In vitro, compared to the OGD/R+NC group, the OGD/R+DDX21 group exhibited lower mitochondrial superoxide levels, higher polymer/monomer ratio, maximal oxygen consumption, reserve capacity, and ATP content. In contrast, the OGD/R+siDDX21 group showed the opposite results, with reduced activity of mitochondrial respiratory chain complex V (all P<0.05). Mechanistically, rMATS software and other analyses indicated that knockdown of DDX21 affected the alternative 3′ splicing sites of ATP5J precursor mRNA, inhibiting the splicing of certain exonic sequences. Overexpression of DDX21 upregulated both mRNA and protein levels of ATP5J. Co-immunoprecipitation experiments showed that, compared to the PBS group, acetylated DDX21 levels were reduced in the A-485 group. Further in vivo experiments showed that, compared to the I/R+PBS group, the I/R+A-485 group exhibited higher left ventricular ejection fraction and fractional shortening, and a lower proportion of left ventricular fibrosis (all P<0.001). Conclusions:DDX21 improves cardiomyocyte energy metabolism and alleviates I/R injury by regulating the alternative splicing of ATP5J. A-485 holds potential as a novel small molecule candidate for the treatment of myocardial injury.

Objective:To investigate the biological role and molecular mechanism of checkpoint kinase 1 (CHK1) in delaying cardiac aging in mice.Methods:In vitro, a senescence model of H9C2 cells (a cardiomyocyte line) was induced using H 2O 2. A control group (without H 2O 2 treatment) and three H 2O 2-treated groups (at concentrations of 10, 30, and 50 μmol/L) were set up. The CCK-8 assay was used to evaluate the proliferative activity of cells in each group; Western blot analysis was employed to detect the expression level of CHK1; and quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the messenger RNA (mRNA) expression levels of P16 and interleukin-1β (IL-1β). In vivo, C57BL/6 wild-type mice aged 2 months ( n=15) and 24 months ( n=40), as well as myocardial-specific CHK1-overexpressing (CHK1-TG) mice aged 2 months ( n=15) and 24 months ( n=40), were selected. The mice were divided into four groups based on age and genotype: 2-month-old wild-type (WT-2M), 24-month-old wild-type (WT-24M), 2-month-old CHK1-TG (CHK1-TG-2M), and 24-month-old CHK1-TG (CHK1-TG-24M). Echocardiography was used to evaluate cardiac function of mice in the WT-24M and CHK1-TG-24M groups. Western blot analysis was conducted to measure the protein expression levels of CHK1, total Ras-related protein 1 (Rap1), NADPH oxidase 4 (Nox4), and Rap1-guanosine triphosphate (Rap1-GTP, the active form of Rap1) in the cardiac tissue of mice in each group. qRT-PCR was used to detect the messenger RNA (mRNA) expression levels of CHK1, collagen type Ⅰ (Coll1), matrix metalloproteinase-2 (Mmp2), alpha-smooth muscle actin (α-SMA), P53, P21, P16, thioredoxin 1 (Trx1), thioredoxin reductase (TrxR), glutathione recluctase (GR), Rap1, and Nox4. Immunofluorescence staining was employed to determine the protein expression levels of P53, P21, and P16, as well as the proportion of histone H2AX phosphorylation-positive cells. Dihydroethidium (DHE) staining was used to detect the relative intensity of DHE. Wheat germ agglutinin staining, HE staining, Masson staining and Sirius red staining were applied to measure the cross-sectional area of cardiomyocytes, cardiac morphology, and myocardial fibrosis area. Mice in the WT-24M and CHK1-TG-24M groups were intraperitoneally injected with the Rap1 activity inhibitor GGTI298 (25 μmol/kg). After injection, the oxidative stress damage in the cardiac tissue of the mice was detected, along with the mRNA expression levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P16, P21, and P53). Results:A concentration of 30 μmol/L was determined as the optimal concentration for establishing an H 2O 2-induced senescence model of myocardial cells in vitro. The expression level of CHK1 in H9C2 cells of the 30 μmol/L H 2O 2 group was lower than that in the control group ( P<0.05). Echocardiographic examination showed that the left ventricular ejection fraction ((61.08±1.13)% vs. (52.55±2.02)%) and fractional shortening ((31.80±1.27)% vs. (25.18±1.59)%) of mice in the CHK1-TG-24M group were higher than those in the WT-24M group (both P<0.05). qRT-PCR and Western blot analysis revealed that, compared with the WT-24M group, mice in CHK1-TG-24M group had higher expression levels of CHK1 and its mRNA, lower expression levels of Nox4 and its mRNA, and higher expression level of Rap1-guanosine triphosphate (Rap1-GTP) (all P<0.05). However, there were no statistically significant differences in the total expression level of Rap1 and its mRNA between the two groups (both P>0.05). In addition, the mRNA expression levels of Coll1, Mmp2, and α-SMA in myocardial tissue of mice in the CHK1-TG-24M group were lower than those in the WT-24M group (all P<0.05). Immunofluorescence staining results showed that the expression levels of P53, P21, and P16 proteins, as well as the proportion of phosphorylated histone H2AX-positive cells in myocardial tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). qRT-PCR further confirmed that the mRNA expression levels of the above-mentioned proteins in cardiac tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). DHE staining results indicated that the relative intensity of DHE in cardiac tissue of mice in the CHK1-TG-24M group was lower than that in the WT-24M group ( P<0.05). Meanwhile, the left ventricular internal diameter, cross-sectional area of cardiomyocytes, and myocardial fibrosis area of mice in the CHK1-TG-24M group were all smaller than those in the WT-24M group (all P<0.05). Furthermore, the degree of DNA damage in cardiac tissue as well as the mRNA levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P53, P21, P16) in mice of the WT-24M+GGTI298 group were higher than those in the WT-24M group and the CHK1-TG-24M+GGTI298 group (all P<0.05). Conclusion:CHK1 alleviates oxidative stress-induced damage in mouse cardiomyocytes by activating the Rap1/Nox4 signaling pathway, thereby delaying cardiac aging in mice.

OBJECTIVE:To analyze the dyeing status of cinnabar and its pieces,and provide reference for its quality clinical safetey appicaton. METHODS:TLC was used for the qualitative identification of amaranth,carmine,erythrosine,acid red 73, 808 udan and indirubin. HPLC-MS was used to detect the 808 udan :HPLC conditions were as follows,column was Acquity UPLC BEH C18 with mobile phase of cetonitrile-0.1% formic acid(70∶30,V/V)at a flow rate of 0.3 ml/min,the detection wave-length was 520 nm;MS conditions were as follows,ion source was electrospray ionization source,scanning mode was positive ion scanning with full scanning tandem mass spectrometry,nebulizer pressure was 30 psi,drying gas was nitrogen,ion spray voltage was 4 000 V,collision energy was 30 V,and the injection volume was 5 μl. The volumetric method was used for content determi-nation of HgS. RESULTS:TLC spots of amaranth,carmine,erythrosine,acid red 73,808 udan and indirubin were clear and well-separated. 4 batches of 808 udan dyeing were included in the 18 batches of samples,6 batches had non-compliance contents (including 3 batches of 808 udan dyeing). CONCLUSIONS:Dyeing-doped and other quality problems exist in the cinnabaris in markets,which should be noticed.