This study aims to elucidate the role and mechanism of clematichinenoside AR(CAR) in protecting bone marrow mesenchymal stem cells(BMSCs) from hypoxia-induced apoptosis. BMSCs were isolated by the bone fragment method and identified by flow cytometry. Cells were cultured under normal conditions(37℃, 5% CO_2) and hypoxic conditions(37℃, 90% N_2, 5% CO_2) and treated with CAR. The BMSCs were classified into eight groups: control(normal conditions), CAR(normal conditions + CAR), hypoxia 24 h, hypoxia 24 h + CAR, hypoxia 48 h, hypoxia 48 h + CAR, hypoxia 72 h, and hypoxia 72 h + CAR. The cell counting kit-8(CCK-8) assay and terminal-deoxynucleoitidyl transferase mediated nick end labeling(TUNEL) were employed to measure cell proliferation and apoptosis, respectively. The number of mitochondria and mitochondrial membrane potential were measured by MitoTracker®Red CM-H2XRo staining and JC-1 staining, respectively. The level of reactive oxygen species(ROS) was measured with the DCFH-DA fluorescence probe. The protein levels of B-cell lymphoma-2 associated X protein(BAX), caspase-3, and optic atrophy 1(OPA1) were determined by Western blot. The results demonstrated that CAR significantly increased cell proliferation. Compared with the control group, the hypoxia groups showed increased apoptosis rates, reduced mitochondria, elevated ROS levels, decreased mitochondrial membrane potential, upregulated expression of BAX and caspase-3, and downregulated expression of OPA1. In comparison to the corresponding hypoxia groups, CAR intervention significantly decreased the apoptosis rate, increased mitochondria, reduced ROS levels, elevated mitochondrial membrane potential, downregulated the expression of BAX and caspase-3, and upregulated the expression of OPA1. Therefore, it can be concluded that CAR may exert an anti-apoptotic effect on BMSCs under hypoxic conditions by regulating OPA1 to maintain mitochondrial homeostasis.
Mesenchymal Stem Cells/metabolism* ; Apoptosis/drug effects* ; Mitochondria/metabolism* ; Animals ; Rats ; Cell Hypoxia/drug effects* ; Homeostasis/drug effects* ; Reactive Oxygen Species/metabolism* ; Rats, Sprague-Dawley ; Membrane Potential, Mitochondrial/drug effects* ; Saponins/pharmacology* ; Caspase 3/genetics* ; Male ; bcl-2-Associated X Protein/genetics* ; Bone Marrow Cells/metabolism* ; Cell Proliferation/drug effects* ; Protective Agents/pharmacology* ; Cells, Cultured

This study aims to investigate the optimal ratio of Astragali Radix-Curcumae Rhizoma(AC) for inhibiting the proliferation of 143B osteosarcoma cells, and to investigate the mechanism by which AC inhibits osteosarcoma growth and metastasis through angiogenesis and cell adhesion mediated by the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/hypoxia inducible factor-1α(HIF-1α) pathway. A subcutaneous 143B tumor-bearing nude mouse model was successfully established and randomly divided into the model group, and the AC 1∶1, 2∶1, and 4∶1 groups. Body weight, tumor volume, and tumor weight were recorded. Real-time quantitative polymerase chain reaction(RT-qPCR) and Western blot were used to detect the mRNA and protein expression levels of PI3K, Akt, phosphorylated Akt(p-Akt), HIF-1α, vascular endothelial growth factor A(VEGFA), transforming growth factor-β1(TGF-β1), epithelial cadherin(E-cadherin), neural cadherin(N-cadherin), vimentin, matrix metalloproteinase 2(MMP2), matrix metalloproteinase 9(MMP9), B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and caspase-3 in the hypoxic core region of the tumor tissue. A cell hypoxia model was established, and the effects of AC-medicated serum(model group, AC 1∶1, 2∶1, and 4∶1 groups) on angiogenesis, proliferation, adhesion, invasion, and migration of 143B osteosarcoma cells were examined through CCK-8, flow cytometry, Transwell assay, cell adhesion assay, and HUVEC tube formation assay. The results showed that compared with the model group, the tumor weight and volume were smallest in the 2∶1 group. The expression levels of PI3K, Akt, p-Akt, HIF-1α, VEGFA, and TGF-β1 were significantly decreased, and the protein expression of E-cadherin was significantly increased, while the protein expression of N-cadherin, vimentin, MMP2, and MMP9 was significantly decreased. Additionally, the protein expression of Bax and caspase-3 was significantly increased, and Bcl-2 protein expression was significantly decreased. In vitro experiments showed that after intervention with AC-medicated serum at a 2∶1 ratio, the cell activity, adhesion, invasion, and migration of 143B cells were significantly reduced, apoptosis was significantly increased, and HUVEC tube formation was significantly decreased. In conclusion, the 2∶1 ratio of AC showed the most effective inhibition of 143B cell growth. AC can inhibit the growth and metastasis of osteosarcoma 143B cells by regulating the PI3K/Akt/HIF-1α signaling pathway, inhibiting angiogenesis and reducing cell adhesion, invasion, and migration.
Osteosarcoma/pathology* ; Animals ; Proto-Oncogene Proteins c-akt/genetics* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; Humans ; Mice ; Cell Adhesion/drug effects* ; Cell Proliferation/drug effects* ; Neovascularization, Pathologic/metabolism* ; Drugs, Chinese Herbal/administration & dosage* ; Phosphatidylinositol 3-Kinases/genetics* ; Cell Line, Tumor ; Mice, Nude ; Signal Transduction/drug effects* ; Astragalus Plant/chemistry* ; Bone Neoplasms/physiopathology* ; Male ; Rhizome/chemistry* ; Mice, Inbred BALB C ; Angiogenesis

This paper explored the specific mechanism of ginsenoside Rg_1 in regulating mitochondrial fusion through the neurogenic gene Notch homologous protein 1(Notch1) pathway to alleviate hypoxia/reoxygenation(H/R) injury in HL-1 cells. The relative viability of HL-1 cells after six hours of hypoxia and two hours of reoxygenation was detected by cell counting kit-8(CCK-8). The lactate dehydrogenase(LDH) activity in the cell supernatant was detected by the lactate substrate method. The content of adenosine triphosphate(ATP) was detected by the luciferin method. Fluorescence probes were used to detect intracellular reactive oxygen species(Cyto-ROS) levels and mitochondrial membrane potential(ΔΨ_m). Mito-Tracker and Actin were co-imaged to detect the number of mitochondria in cells. Fluorescence quantitative polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels of Notch1, mitochondrial fusion protein 2(Mfn2), and mitochondrial fusion protein 1(Mfn1). The results showed that compared with that of the control group, the cell activity of the model group decreased, and the LDH released into the cell culture supernatant increased. The level of Cyto-ROS increased, and the content of ATP decreased. Compared with that of the model group, the cell activity of the ginsenoside Rg_1 group increased, and the LDH released into the cell culture supernatant decreased. The level of Cyto-ROS decreased, and the ATP content increased. Ginsenoside Rg_1 elevated ΔΨ_m and increased mitochondrial quantity in HL-1 cells with H/R injury and had good protection for mitochondria. After H/R injury, the mRNA and protein expression levels of Notch1 and Mfn1 decreased, while the mRNA and protein expression levels of Mfn2 increased. Ginsenoside Rg_1 increased the mRNA and protein levels of Notch1 and Mfn1, and decreased the mRNA and protein levels of Mfn2. Silencing Notch1 inhibited the action of ginsenoside Rg_1, decreased the mRNA and protein levels of Notch1 and Mfn1, and increased the mRNA and protein levels of Mfn2. In summary, ginsenoside Rg_1 regulated mitochondrial fusion through the Notch1 pathway to alleviate H/R injury in HL-1 cells.
Ginsenosides/pharmacology* ; Receptor, Notch1/genetics* ; Signal Transduction/drug effects* ; Mice ; Animals ; Mitochondrial Dynamics/drug effects* ; Mitochondria/metabolism* ; Cell Line ; Reactive Oxygen Species/metabolism* ; Oxygen/metabolism* ; Cell Hypoxia/drug effects* ; Cell Survival/drug effects* ; Membrane Potential, Mitochondrial/drug effects* ; Humans

This study aims to explore the mechanism of Buyang Huanwu Decoction(BHD) in promoting angiogenesis after oxygen-glucose deprivation/reoxygenation(OGD/R) of mouse brain microvascular endothelial cell line(brain-derived Endothelial cells.3, bEnd.3) based on the caveolin-1(Cav1)/Yes-associated protein 1(YAP1)/hypoxia-inducible factor-1α(HIF-1α) signaling pathway. Ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was used to analyze the blood components of BHD. The cell counting kit-8(CCK-8) method was used to detect the optimal intervention concentration of drug-containing serum of BHD after OGD/R injury of bEnd.3. The lentiviral transfection method was used to construct a Cav1 silent stable strain, and Western blot and polymerase chain reaction(PCR) methods were used to verify the silencing efficiency. The control bEnd.3 cells were divided into a normal group(sh-NC control group), an OGD/R model + blank serum group(sh-NC OGD/R group), and an OGD/R model + drug-containing serum group(sh-NC BHD group). Cav1 silent cells were divided into an OGD/R model + blank serum group(sh-Cav1 OGD/R group) and an OGD/R model + drug-containing serum group(sh-Cav1 BHD group). The cell survival rate was detected by the CCK-8 method. The cell migration ability was detected by a cell migration assay. The lumen formation ability was detected by an angiogenesis assay. The apoptosis rate was detected by flow cytometry, and the expression of YAP1/HIF-1α signaling pathway-related proteins in each group was detected by Western blot. Finally, co-immunoprecipitation was used to verify the interaction between YAP1 and HIF-1α. The results showed astragaloside Ⅳ, formononetin, ferulic acid, and albiflorin in BHD can all enter the blood. The drug-containing serum of BHD at a mass fraction of 10% may be the optimal intervention concentration for OGD/R-induced injury of bEnd.3 cells. Compared with the sh-NC control group, the sh-NC OGD/R group showed significantly decreased cell survival rate, cell migration rate, mesh number, node number, and lumen length, significantly increased cell apoptotic rate, significantly lowered phosphorylation level of YAP1 at S127 site, and significantly elevated nuclear displacement level of YAP1 and protein expression of HIF-1α, vascular endothelial growth factor(VEGF), and vascular endothelial growth factor receptor 2(VEGFR2). Compared with the same type of OGD/R group, the sh-NC BHD group and sh-Cav1 BHD group had significantly increased cell survival rate, cell migration rate, mesh number, node number, and lumen length, a significantly decreased cell apoptotic rate, a further decreased phosphorylation level of YAP1 at S127 site, and significantly increased nuclear displacement level of YAP1 and protein expression of HIF-1α, VEGF, and VEGFR2. Compared with the sh-NC OGD/R group, the sh-Cav1 OGD/R group exhibited significantly decreased cell survival rate, cell migration rate, mesh number, node number, and lumen length, a significantly increased cell apoptotic rate, a significantly increased phosphorylation level of YAP1 at S127 site, and significantly decreased nuclear displacement level of YAP1 and protein expression of HIF-1α, VEGF, and VEGFR2. Compared with the sh-NC BHD group, the sh-Cav1 BHD group showed significantly decreased cell survival rate, cell migration rate, mesh number, node number, and lumen length, a significantly increased cell apoptotic rate, a significantly increased phosphorylation level of YAP1 at the S127 site, and significantly decreased nuclear displacement level of YAP1 and protein expression of HIF-1α, VEGF, and VEGFR2. YAP1 protein was present in the protein complex precipitated by the HIF-1α antibody, and HIF-1α protein was also present in the protein complex precipitated by the YAP1 antibody. The results confirmed that the drug-containing serum of BHD can increase the activity of YAP1/HIF-1α pathway in bEnd.3 cells damaged by OGD/R through Cav1 and promote angiogenesis in vitro.
Drugs, Chinese Herbal/pharmacology* ; Animals ; Mice ; Signal Transduction/drug effects* ; Glucose/metabolism* ; Caveolin 1/genetics* ; Hypoxia-Inducible Factor 1, alpha Subunit/genetics* ; YAP-Signaling Proteins ; Oxygen/metabolism* ; Endothelial Cells/metabolism* ; Cell Line ; Adaptor Proteins, Signal Transducing/genetics* ; Neovascularization, Physiologic/drug effects* ; Cell Hypoxia/drug effects* ; Angiogenesis

OBJECTIVES: To investigate whether human umbilical cord mesenchymal stem cells (HUC-MSCs) play protective effects against white matter injury (WMI) in neonatal rats via activation of the nuclear factor-erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)/heme oxygenase-1 (HO-1) signaling pathway. METHODS: A neonatal WMI model was established in 3-day-old Sprague-Dawley rats by unilateral common carotid artery ligation combined with hypoxia. The study comprised two parts. (1) Rats were randomized into sham, hypoxia-ischemia (HI), and HUC-MSC groups (n=36 per group); brain tissues were collected at 7, 14, and 21 days after modeling. (2) Rats were randomized into sham, HI, HUC-MSC, and HUC-MSC+ML385 (Nrf2 inhibitor) groups (n=12 per group); tissues were collected 14 days after modeling. Hematoxylin-eosin staining assessed histopathology, and Luxol fast blue staining evaluated myelination. Immunohistochemistry examined the localization and expression of Nrf2, myelin basic protein (MBP), and proteolipid protein (PLP). Immunofluorescence assessed synaptophysin (SYP) and postsynaptic density-95 (PSD-95). Western blotting quantified Nrf2, Keap1, HO-1, SYP, PSD-95, MBP, and PLP. Spatial learning and memory were evaluated by the Morris water maze. RESULTS: At 7, 14, and 21 days after modeling, the sham group showed intact white matter, whereas the HI group exhibited white matter disruption, cellular vacuolation, and disorganized nerve fibers. These pathological changes were attenuated in the HUC-MSC group. Compared with the HI group, the HUC-MSC group showed increased Nrf2 immunopositivity and protein levels, increased HO-1 protein levels, and decreased Keap1 protein levels (P<0.05). Compared with the HI group, the HUC-MSC group had higher SYP and PSD-95 immunofluorescence intensities and protein levels, higher MBP and PLP positivity and protein levels, increased mean optical density of myelin, more platform crossings, and longer time in the target quadrant (all P<0.05). These improvements were reduced in the HUC-MSC+ML385 group compared with the HUC-MSC group (P<0.05). CONCLUSIONS HUC-MSCs may promote oligodendrocyte maturation and synaptogenesis after neonatal WMI by activating the Nrf2/Keap1/HO-1 pathway, thereby improving spatial cognitive function.
NF-E2-Related Factor 2/physiology* ; Animals ; Rats, Sprague-Dawley ; Signal Transduction/physiology* ; Humans ; Rats ; White Matter/pathology* ; Kelch-Like ECH-Associated Protein 1/physiology* ; Umbilical Cord/cytology* ; Heme Oxygenase-1/physiology* ; Animals, Newborn ; Male ; Mesenchymal Stem Cell Transplantation ; Heme Oxygenase (Decyclizing)/physiology* ; Mesenchymal Stem Cells/physiology* ; Female ; Hypoxia-Ischemia, Brain

OBJECTIVES: Hypoxia/reoxygenation (H/R) injury is a critical pathological process during liver transplantation. Kazinol B has known anti-inflammatory, anti-apoptotic, and metabolic regulatory properties, but its protective mechanism in H/R-induced liver injury remains unclear. This study aims to investigate the protective effects and underlying mechanisms of Kazinol B in H/R-induced hepatocyte injury. METHODS: An ischemia-reperfusion model was established in healthy adult male Sprague-Dawley rats, and an in vitro H/R model was created using cultured hepatocytes. Hepatocytes were treated with Kazinol B (0-100 μmol/L) to assess cytotoxicity and protective effects. Cell viability was evaluated using the cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) release assays. Expression of apoptosis-related proteins, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated death promoter (Bad), and cleaved caspase-3, was detected by Western blotting. Reactive oxygen species (ROS) levels were assessed via fluorescence probes, and inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured using enzyme-linked immunosorbent assay (ELISA). TdT-mediated nick end labeling (TUNEL) staining was performed to assess DNA damage and apoptosis. RESULTS: Kazinol B had no significant effect on hepatocyte viability at 0-50 μmol/L, but showed cytotoxicity at 100 μmol/L (P<0.05). At 0.1-20 μmol/L, Kazinol B significantly improved cell survival, reduced LDH release, decreased apoptosis, and attenuated DNA damage (all P<0.001). At 10 μmol/L, Kazinol B markedly down-regulated Bad and cleaved caspase-3 (both P<0.05), and up-regulated Bcl-2 (P<0.01). It also dose-dependently reduced ROS levels and inflammatory cytokines TNF-α and IL-1β (all P<0.01). Both in vitro and in vivo, Kazinol B inhibited activation of the c-Jun N-terminal kinase (JNK) pathway without affecting extracellular regulated protein kinase (ERK) signaling (P>0.05). TUNEL staining showed that the protective effect of Kazinol B against apoptosis was partially reversed by the JNK agonist anisomycin (P<0.01). CONCLUSIONS Kazinol B mitigates hepatocyte injury induced by H/R by inhibiting the JNK signaling pathway. Its protective effect is associated with suppression of oxidative stress and inflammation, indicating its potential as a hepatoprotective agent.
Animals ; Hepatocytes/pathology* ; Rats, Sprague-Dawley ; Male ; Rats ; Reperfusion Injury/prevention & control* ; Apoptosis/drug effects* ; Reactive Oxygen Species/metabolism* ; MAP Kinase Signaling System/drug effects* ; Cell Survival/drug effects* ; Cell Hypoxia ; Cells, Cultured

OBJECTIVES: Injury to human cardiac microvascular endothelial cells (HCMECs) compromises myocardial microcirculation and may contribute to major cardiovascular events such as coronary heart disease, posing a serious health threat. Understanding the mechanisms of hypoxia-induced HCMEC damage is thus of great clinical relevance. This study aims to investigate the protective effects and underlying mechanisms of Li Qi Huo Xue Di Wan against hypoxia-induced HCMEC injury. METHODS: HCMECs were cultured under hypoxic conditions for 24 hours to establish a cellular model of hypoxic injury. Cells were divided into six groups: normal control, hypoxia, hypoxia + low-dose Li Qi Huo Xue Di Wan, hypoxia + medium-dose, hypoxia + high-dose, and hypoxia + salvianolic acid B (positive control). Cell viability was assessed using the MTS assay. Lactate dehydrogenase (LDH) release and malondialdehyde (MDA) content were measured to evaluate cytotoxicity and oxidative stress. Activities of superoxide dismutase (SOD), catalase (CAT), caspase-3, and caspase-8 were determined with corresponding assay kits. Apoptosis was analyzed by flow cytometry, and expression of necroptosis-related proteins, receptor-interacting protein kinase 1 (RIPK1) and its phosphorylated form (p-RIPK1), receptor-interacting protein kinase 3 (RIPK3) and its phosphorylated form (p-RIPK3), mixed lineage kinase domain-like protein (MLKL) and its phosphorylated form (p-MLKL), was examined via Western blotting. RESULTS: Compared with the control group, hypoxia significantly decreased cell viability (P<0.01), increased MDA levels (P<0.05), and reduced CAT and SOD activity (P<0.05), accompanied by elevated apoptosis (P<0.01) and increased levels of p-RIPK1, p-RIPK3, and p-MLKL (P<0.05). High-dose Li Qi Huo Xue Di Wan significantly improved cell viability (P<0.01), reduced MDA content (P<0.05), increased CAT activity (P<0.05), and suppressed necroptosis-related protein expression (P<0.05) compared with the hypoxia group. CONCLUSIONS Li Qi Huo Xue Di Wan exerts a protective effect against hypoxia-induced injury in HCMECs. This effect is mediated by attenuation of oxidative stress, thereby reducing both apoptosis and necroptosis.
Humans ; Apoptosis/drug effects* ; Necroptosis/drug effects* ; Drugs, Chinese Herbal/pharmacology* ; Cell Hypoxia/drug effects* ; Endothelial Cells/pathology* ; Oxidative Stress/drug effects* ; Cells, Cultured ; Cell Survival/drug effects* ; Receptor-Interacting Protein Serine-Threonine Kinases/metabolism*

Hypoxia and aberrant activation of epidermal growth factor receptor (EGFR) are considered important features of various malignancies. However, whether hypoxia can directly trigger EGFR activation and its clinical implications remain unclear. In this study, we demonstrated that in oral cancer, a typical hypoxic tumor, hypoxia can induce chronic but constitutive phosphorylation of wild-type EGFR in the absence of ligands. Oral cancer cell lines exhibit different EGFR phosphorylation responses to hypoxia. In hypoxic HN4 and HN6 cells, ubiquitination-mediated endocytosis, lysosomal sorting, and degradation lead to low levels of EGFR phosphorylation. However, in CAL-27 and HN30 cells, a novel HIF-1α-induced long noncoding RNA (lncRNA), EUDAL, can compete with the E3 ligase/adaptor complex c-Cbl/Grb2 for binding to EGFR, stabilizing phosphorylated EGFR (pEGFR) and resulting in sustained activation of EGFR and its downstream STAT3/BNIP3 signaling. STAT3/BNIP3-mediated autophagy leads to antitumor drug resistance. A high EUDAL/EGFR/STAT3/autophagy pathway activation predicts poor response to chemotherapy in oral cancer patients. Collectively, hypoxia can induce noncanonical ligand-independent EGFR phosphorylation. High EUDAL expression facilitates sustained EGFR phosphorylation in hypoxic tumor cells and leads to autophagy-related drug resistance.
Humans ; ErbB Receptors/metabolism* ; Mouth Neoplasms/pathology* ; RNA, Long Noncoding/genetics* ; Drug Resistance, Neoplasm/genetics* ; Cell Line, Tumor ; Phosphorylation ; Signal Transduction ; STAT3 Transcription Factor/metabolism* ; Cell Hypoxia ; Autophagy ; Proto-Oncogene Proteins c-cbl/metabolism*

OBJECTIVE: To investigate the effects of calcitonin gene-related peptide (CGRP) on autophagy in hypoxic/reoxygenated (H/R) cardiomyocytes and its relationship with the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway. METHODS: The rat cardiomyocyte cell line H9c2 was routinely cultured in vitro and passaged for experiments when the cells grew to 80% fusion. (1) CGRP dosage screening experiment: the cells were divided into blank control group, H/R group and different dosages of CGRP pretreatment groups. H9c2 cells were placed in a closed hypoxia chamber for 2 hours and then reoxygenated in a conventional incubator for 12 hours to prepare the H/R model. The CGRP pretreatment groups were pretreated with 0.01, 0.1, 0.5, 1, 5, and 10 μmol/L CGRP before the modeling process. The blank control group was not given any treatment. Cell counting kit-8 (CCK-8) was used to detect the cell survival rate, and the most suitable drug dosage was screened out. (2) Intervention experiment: H9c2 cells were divided into blank control group, H/R group, CGRP+H/R group, and CGRP+PI3K target inhibitor ly294002 (LY)+H/R group. H/R group was prepared as cellular H/R model. CGRP (1 μmol/L) alone or in combination with LY (10 μmol/L) was administered to CGRP+H/R group and CGRP+LY+H/R group, respectively, prior to the preparation of cellular H/R model. The blank control group was cultured routinely without treatment. The cell survival rate was detected by CCK-8. The level of lactate dehydrogenase (LDH) release was detected by colorimetric assay. The expressions of autophagy-related proteins [autophagy effector protein Beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II), autophagy protein p62] and PI3K/Akt/mTOR signaling pathway proteins [phosphorylated Akt (p-Akt), phosphorylated mTOR (p-mTOR)] were detected by Western blotting. RESULTS: (1) Results of CGRP dosage screening experiment: compared with the blank control group, the cell survival rate of the H/R group decreased significantly; and after giving 0.1, 0.5, 1, 5 μmol/L CGRP for pretreatment, the cell survival rate increased significantly, and intervention effect of 1 μmol/L CGRP was the best, and the difference was statistically significant when compared with that of the H/R group [(74.23±6.18)% vs. (23.43±4.09)%, P < 0.01], so it was used as the intervention dosage for the subsequent experiment. (2) Intervention experiment results: compared with the blank control group, the cell survival rate in the H/R group was significantly reduced, the level of LDH release was significantly increased, the protein expressions of Beclin-1 and LC3-II were significantly increased, and the protein expressions of p62, p-Akt and p-mTOR were significantly reduced, indicating that the death of cardiomyocytes occurred after the treatment of H/R and was accompanied by the elevation of autophagy level, and this process was associated with the activation of PI3K/Akt/mTOR signaling pathway. Compared with the H/R group, CGRP pretreatment increased cell survival rate [(76.02±2.43)% vs. (46.15±3.29)%, P < 0.01], decreased the level of LDH release (U/L: 169.83±11.65 vs. 590.17±34.50, P < 0.01), and down-regulated the protein expressions of Beclin-1 and LC3-II [Beclin-1 protein (Beclin-1/β-actin): 1.27±0.15 vs. 1.93±0.19, LC3-II protein (LC3-II/LC3-I): 1.27±0.13 vs. 1.98±0.18, both P < 0.01], up-regulated the protein expressions of p62, p-Akt, p-mTOR [p62 protein (p62/β-actin): 0.96±0.02 vs. 0.63±0.05, p-Akt protein (p-Akt/Akt): 0.76±0.04 vs. 0.48±0.02, p-mTOR protein (p-mTOR/mTOR): 1.13±0.09 vs. 0.68±0.15, all P < 0.05], suggesting that CGRP was able to reduce the H/R-induced cardiomyocyte injury, and this process was accompanied by a decrease in the level of cellular autophagy and activation of the PI3K/Akt/mTOR signaling pathway. Compared with the CGRP+H/R group, the cell survival rate was significantly lower than that in the CGRP+LY+H/R group [(56.95±6.63)% vs. (76.02±2.43)%, P < 0.01], LDH release level was significantly higher (U/L: 436.00±27.44 vs. 169.83±11.65, P < 0.01), and the protein expressions of Beclin-1 and LC3-II were significantly up-regulated [Beclin-1 protein (Beclin-1/β-actin): 1.63±0.12 vs. 1.27±0.15, LC3-II protein (LC3-II/LC3-I): 1.61±0.13 vs. 1.27±0.13, both P < 0.01], and significantly down-regulated p62, p-Akt, and p-mTOR protein expressions [p62 protein (p62/β-actin): 0.57±0.09 vs. 0.96±0.02, p-Akt protein (p-Akt/Akt): 0.45±0.01 vs. 0.76±0.04, p-mTOR protein (p-mTOR/mTOR): 0.66±0.06 vs. 1.13±0.09, all P < 0.05], suggesting that PI3K-targeted inhibitor was able to reverse the protective effect of CGRP on H/R cells. CONCLUSIONS CGRP pretreatment attenuated H/R-induced cardiomyocyte injury, increased cell survival rate, and reduced cellular LDH release. This effect may be achieved through inhibiting the activation of PI3K/Akt/mTOR signaling pathway.
Animals ; Myocytes, Cardiac/drug effects* ; Signal Transduction/drug effects* ; Rats ; TOR Serine-Threonine Kinases/metabolism* ; Calcitonin Gene-Related Peptide/pharmacology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Autophagy/drug effects* ; Cell Line ; Cell Hypoxia ; Phosphatidylinositol 3-Kinases/metabolism*

OBJECTIVE: To elucidate the role and mechanism of microRNA-145-5p (miR-145-5p) in hypoxia-induced pyroptosis of human alveolar epithelial cells. METHODS: In vitro, human alveolar epithelial cell line BEAS-2B was cultured. Cells in the logarithmic growth phase were cultured to 80% confluence and then used for the experiment. (1) BEAS-2B cells were cultured under 1% O₂ hypoxic condition, with a normoxic control group. Western blotting was employed to detect the expressions of pyroptosis marker proteins [NOD-like receptor protein 3 (NLRP3), Gasdermin D N-terminal domain (GSDMD-N), and caspase-1] in cells cultured for 24 hours. Real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of miR-145-5p in cells cultured for 6 hours and 12 hours. (2) Cells were transfected with 30 nmol/L miR-145-5p mimic to overexpress miR-145-5p expression under normoxic condition or 30 nmol/L miR-145-5p inhibitor to suppress miR-145-5p expression under hypoxic condition. Control group and negative control group were respectively set up. After 24 hours of cell culture, Western blotting was used to detect the expressions of pyroptosis marker proteins and nuclear factor-E2-related factor 2 (Nrf2) in cells. Flow cytometry was applied to detect the level of reactive oxygen species (ROS) in cells. The target genes of miR-145-5p were predicted by miR target gene prediction software miRWalk and verified by Western blotting. (3) Under hypoxic condition, cells were transfected with 6.94 ng/μL silent information regulator 5 (Sirt5) overexpression plasmid or pretreated with 12.5 mmol/L N-acetyl-L-cysteine (NAC) as an ROS inhibitor. The empty plasmid group and control group were set up. After 24 hours of cell culture, Western blotting was used to detect the expressions of Sirt5, Nrf2, and pyroptosis marker proteins in cells. Flow cytometry was used to detect the level of ROS in cells. RESULTS: (1) Compared with the normoxic control group, the expression levels of pyroptosis marker proteins in the 24-hour hypoxia group was significantly increased, indicating that hypoxia could induce pyroptosis in BEAS-2B cells. The expression level of miR-145-5p in cells gradually increased with the extension of hypoxia induction time, indicating that hypoxia could cause the increase of miR-145-5p expression level. (2) The expression levels of pyroptosis marker proteins in cells of miR-145-5p mimic group significantly increased under normoxic condition as compared with the control and negative control groups [NLRP3 protein (NLRP3/β-actin): 1.58±0.07 vs. 1.00±0.01, 0.98±0.07, GSDMD-N protein (GSDMD-N/β-actin): 1.71±0.03 vs. 1.01±0.01, 0.85±0.03, caspase-1 protein (caspase-1/β-actin): 2.33±0.04 vs. 1.01±0.01, 1.05±0.04, all P < 0.05], Nrf2 protein expression level was significantly decreased (Nrf2/β-actin: 0.79±0.03 vs. 1.00±0.01, 1.03±0.04, both P < 0.05), ROS level was significantly up-regulated (fluorescence intensity: 1.74±0.03 vs. 1.00±0.01, 0.92±0.03, both P < 0.05). Under hypoxia condition, compared with control group and negative control group, the expression levels of pyroptosis marker proteins in miR-145-5p inhibitor group were significantly decreased [NLRP3 protein (NLRP3/β-actin): 0.21±0.04 vs. 1.70±0.02, 1.63±0.04; GSDMD-N protein (GSDMD-N/β-actin): 1.32±0.02 vs. 2.51±0.02, 2.72±0.03; caspase-1 protein (caspase-1/β-actin): 0.56±0.01 vs. 2.77±0.02, 3.12±0.03; all P < 0.05], Nrf2 protein expression level was significantly increased (Nrf2/β-actin: 1.57±0.04 vs. 1.22±0.01, 1.28±0.04, both P < 0.05), ROS level was significantly down-regulated (fluorescence intensity: 0.64±0.05 vs. 1.87±0.04, 1.70±0.07, both P < 0.05). The results indicated that miR-145-5p could promote cell pyrodeath. The predictive result of miRWalk showed that the 3' untranslated region (3'UTR) of Sirt5 had complementary base binding sites with miR-145-5p. The expression level of Sirt5 protein in cells of miR-145-5p mimic group was significantly lower than that of control group and negative control group under normoxic condition (Sirt5/β-actin: 0.59±0.03 vs. 1.00±0.01, 1.01±0.03, both P < 0.05), which verified that Sirt5 was the target gene of miR-145-5p. (3) The occurrence of pyrodeath could be partially reversed by transfection with Sirt5 overexpression plasmid or adding ROS inhibitor NAC into cells, and Sirt5 overexpression could also up-regulate Nrf2 expression and eliminate intracellular ROS. CONCLUSION In human alveolar epithelial cells, miR-145-5p can down-regulate Nrf2 by targeting Sirt5, thereby increasing ROS expression and inducing pyrodeath.
Humans ; MicroRNAs ; Pyroptosis ; Cell Hypoxia ; Alveolar Epithelial Cells/cytology* ; Cell Line ; NLR Family, Pyrin Domain-Containing 3 Protein ; Caspase 1/metabolism* ; Epithelial Cells/metabolism* ; Gasdermins ; Phosphate-Binding Proteins