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Zhu Z, Ling X, Zhou H, Zhang C. Dexmedetomidine at a dose of 1 µM attenuates H9c2 cardiomyocyte injury under 3 h of hypoxia exposure and 3 h of reoxygenation through the inhibition of endoplasmic reticulum stress. Exp Ther Med 2020; 21:132. [PMID: 33376514 PMCID: PMC7751463 DOI: 10.3892/etm.2020.9564] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/20/2020] [Indexed: 12/11/2022] Open
Abstract
Myocardial ischemia-reperfusion injury (MIRI) has been confirmed to induce endoplasmic reticulum stress (ERS) during downstream cascade reactions after the sufficient deterioration of cardiomyocyte function. However, clinically outcomes have been inconsistent with experimental findings because the mechanism has not been entirely elucidated. Dexmedetomidine (DEX), an α2 adrenergic receptor agonist with anti-inflammatory and organ-protective activity, has been shown to attenuate IRI in the heart. The present study aimed to determine whether DEX is able to protect injured cardiomyocytes under in vitro hypoxia/reoxygenation (H/R) conditions and evaluate the conditions under which ERS is efficiently ameliorated. The cytotoxicity of DEX in H9c2 cells was evaluated 24 h after treatment with several different concentrations of DEX. The most appropriate H/R model parameters were determined by the assessment of cell viability and injury with Cell Counting Kit-8 and lactate dehydrogenase (LDH) release assays after incubation under hypoxic conditions for 3 h and reoxygenation conditions for 3, 6, 12 and 24 h. Additionally, the aforementioned methods were used to assess cardiomyocytes cultured with various concentrations of DEX under H/R conditions. Furthermore, the degree of apoptosis and the mRNA and protein expression levels of glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP) and caspase-12 were evaluated in all groups. The addition of 1, 5 and 10 µM DEX to the cell culture significantly increased the proliferation of H9c2 cells by >80% under normal culture conditions. In the H/R model assessment, following 3 h of anoxia exposure, H9c2 cell viability decreased to 62.67% with 3 h of reoxygenation and to 36% with 6 h of reoxygenation compared with the control. The viability of H9c2 cells subjected to hypoxia for 3 h and reoxygenation for 3 h increased by 61.3% when pretreated with 1 µM DEX, and the LDH concentration in the supernatant was effectively decreased by 13.7%. H/R significantly increased the percentage of apoptotic cells, as detected by flow cytometry, and increased the expression levels of GRP78, CHOP and caspase-12, while treatment with either DEX or 4-phenylbutyric acid (4-PBA) significantly attenuated these effects. Additionally, despite the protective effect of DEX against H/R injury, 4-PBA attenuated the changes induced by DEX and H/R. In conclusion, treatment with 1 µM DEX alleviated cell injury, apoptosis and the increases in GRP78, CHOP and caspase-12 expression levels in H9c2 cells induced by 3 h of hypoxia and 3 h of reoxygenation.
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Affiliation(s)
- Zhipeng Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang 314000, P.R. China
| | - Xiaoyan Ling
- Outpatient Nursing Department, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang 314000, P.R. China
| | - Hongmei Zhou
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang 314000, P.R. China
| | - Caijun Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang 314000, P.R. China
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Zhu Z, Ling X, Zhou H, Zhang C, Yan W. Dexmedetomidine Attenuates Cellular Injury and Apoptosis in H9c2 Cardiomyocytes by Regulating p-38MAPK and Endoplasmic Reticulum Stress. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:4231-4243. [PMID: 33116411 PMCID: PMC7568428 DOI: 10.2147/dddt.s265970] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/19/2020] [Indexed: 12/18/2022]
Abstract
Background Myocardial ischaemia-reperfusion injury (IRI) has been confirmed to induce endoplasmic reticulum stress (ERS) when myocardial cell function continues to deteriorate to a certain degree. The clinical applications of effective tested strategies are sometimes inconsistent with the applications evaluated in experiments, although reasonable mechanisms and diverse signalling pathways have been broadly explored. Dexmedetomidine (DEX) has been shown to attenuate IRI of the heart in animal studies. This study aimed to determine whether DEX can protect injured cardiomyocytes under hypoxia/reoxygenation (H/R) at the cellular level and whether the mechanism is related to ERS and the p38 MAPK pathway. Methods H9c2 cells were subjected to H/R or thapsigargin (TG) to build a model. DEX or 4-PBA was added to the medium either 1 h or 24 h before modelling, respectively. Model parameters were determined by assessing cell viability and injury, which were measured by assessing cell counting kit-8 (CCK8), lactate dehydrogenase (LDH) release and flow cytometry results, and the expression of GRP78, CHOP and caspase-12. In addition, the protein expression of p38MAPK and p-p38MAPK was examined, and SB202190, a negative regulator, was also preincubated in medium. Results Compared to that of cells in the control group, the activity of cells in the H/R and TG groups was decreased dramatically, and the LDH concentration and proportion of apoptotic cells were increased. DEX could correspondingly reverse the changes induced by H/R or TG. Additionally, DEX effectively attenuated ERS defined as increased expression of GRP78, CHOP and caspase-12. Additionally, DEX could obviously depress the P38 MAPK phosphorylation and high p-p38 MAPK expression in the TG group, indicating DEX has a function similar to that of SB202190. Conclusion H/R injury in H9c2 cells can lead to abnormal ERS and apoptosis, as well as activation of the p38MAPK signalling pathway. DEX can protect cardiomyocytes by intervening in ERS, regulating p38MAPK and the downstream apoptotic signalling pathway.
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Affiliation(s)
- Zhipeng Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing City, Zhejiang Province 314000, People's Republic of China
| | - Xiaoyan Ling
- The Outpatient Nursing Department of the Second Affiliated Hospital of Jiaxing University, Jiaxing City, Zhejiang Province 314000, People's Republic of China
| | - Hongmei Zhou
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing City, Zhejiang Province 314000, People's Republic of China
| | - Caijun Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing City, Zhejiang Province 314000, People's Republic of China
| | - Weiwei Yan
- Department of Anesthesiology, The Second Affiliated Hospital of Jiaxing University, Jiaxing City, Zhejiang Province 314000, People's Republic of China
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Gao M, Lu W, Shu Y, Yang Z, Sun S, Xu J, Gan S, Zhu S, Qiu G, Zhuo F, Xu S, Wang Y, Chen J, Wu X, Huang J. Poldip2 mediates blood-brain barrier disruption and cerebral edema by inducing AQP4 polarity loss in mouse bacterial meningitis model. CNS Neurosci Ther 2020; 26:1288-1302. [PMID: 32790044 PMCID: PMC7702237 DOI: 10.1111/cns.13446] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 06/27/2020] [Accepted: 07/05/2020] [Indexed: 12/20/2022] Open
Abstract
Background Specific highly polarized aquaporin‐4 (AQP4) expression is reported to play a crucial role in blood‐brain barrier (BBB) integrity and brain water transport balance. The upregulation of polymerase δ‐interacting protein 2 (Poldip2) was involved in aggravating BBB disruption following ischemic stroke. This study aimed to investigate whether Poldip2‐mediated BBB disruption and cerebral edema formation in mouse bacterial meningitis (BM) model occur via induction of AQP4 polarity loss. Methods and Results Mouse BM model was induced by injecting mice with group B hemolytic streptococci via posterior cistern. Recombinant human Poldip2 (rh‐Poldip2) was administered intranasally at 1 hour after BM induction. Small interfering ribonucleic acid (siRNA) targeting Poldip2 was administered by intracerebroventricular (i.c.v) injection at 48 hours before BM induction. A specific inhibitor of matrix metalloproteinases (MMPs), UK383367, was administered intravenously at 0.5 hour before BM induction. Western blotting, immunofluorescence staining, quantitative real‐time PCR, neurobehavioral test, brain water content test, Evans blue (EB) permeability assay, transmission electron microscopy (TEM), and gelatin zymography were carried out. The results showed that Poldip2 was upregulated and AQP4 polarity was lost in mouse BM model. Both Poldip2 siRNA and UK383367 improved neurobehavioral outcomes, alleviated brain edema, preserved the integrity of BBB, and relieved the loss of AQP4 polarity in BM model. Rh‐Poldip2 upregulated the expression of MMPs and glial fibrillary acidic protein (GFAP) and downregulated the expression of β‐dystroglycan (β‐DG), zonula occludens‐1 (ZO‐1), occludin, and claudin‐5; whereas Poldip2 siRNA downregulated the expression of MMPs and GFAP, and upregulated β‐DG, ZO‐1, occludin, and claudin‐5. Similarly, UK383367 downregulated the expression of GFAP and upregulated the expression of β‐DG, ZO‐1, occludin, and claudin‐5. Conclusion Poldip2 inhibition alleviated brain edema and preserved the integrity of BBB partially by relieving the loss of AQP4 polarity via MMPs/β‐DG pathway.
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Affiliation(s)
- Meng Gao
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Weitian Lu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Yue Shu
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Zhengyu Yang
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Shanquan Sun
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Jin Xu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shengwei Gan
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shujuan Zhu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Guoping Qiu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Fei Zhuo
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Shiye Xu
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Yiying Wang
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Junhong Chen
- Department of Anatomy, Chongqing Medical University, Chongqing, China
| | - Xuan Wu
- Department of Neurosurgery, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Juan Huang
- Department of Anatomy, Chongqing Medical University, Chongqing, China.,Institute of Neuroscience, Chongqing Medical University, Chongqing, China
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