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Yang Y, Jiang S, Mu Y, Liu C, Han Y, Jiang J, Wang Y. Berberine prevents against myocardial injury induced by acute β-adrenergic overactivation in rats. J Appl Toxicol 2024. [PMID: 38981847 DOI: 10.1002/jat.4659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/23/2024] [Accepted: 06/06/2024] [Indexed: 07/11/2024]
Abstract
The overactivation of β-adrenergic receptors (β-ARs) can result in acute myocardial ischemic injury, culminating in myocardial necrosis. Berberine (BBR) has exhibited promising potential for prevention and treatment in various heart diseases. However, its specific role in mitigating myocardial injury induced by acute β-AR overactivation remains unexplored. This study aimed to investigate the effects and underlying mechanisms of BBR pretreatment in a rat model of acute β-AR overactivation induced by a single dose of the nonselective β-adrenergic agonist isoprenaline (ISO). Rats were pretreated with saline or BBR (100 mg/kg/day) via gavage for 14 consecutive days, followed by a subcutaneous injection of ISO or saline on the 14th day. The findings indicated that BBR pretreatment significantly attenuated myocardial injury in ISO-stimulated rats, as evidenced by reduced pathological inflammatory infiltration, necrosis, and serum markers of myocardial damage. Additionally, BBR decreased oxidative stress and inflammation in the system and heart. Furthermore, BBR pretreatment enhanced myocardial ATP levels, improved mitochondrial dysfunction through increased Drp1 phosphorylation, and augmented myocardial autophagy. In a CoCl2-induced H9c2 cell hypoxic injury model, BBR pretreatment mitigated cellular injury, apoptosis, and oxidative stress while upregulating Drp1 and autophagy-associated proteins. Mechanistically, BBR pretreatment activated AKT, AMPK, and LKB1 both in vivo and in vitro, implicating the involvement of the AKT and LKB1/AMPK signaling pathways in its cardioprotective effects. Our study demonstrated the protective effects of BBR against myocardial injury induced by acute β-AR overactivation in rats, highlighting the potential of BBR as a preventive agent for myocardial injury associated with β-adrenergic overactivation.
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Affiliation(s)
- Yalin Yang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shuang Jiang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yu Mu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chilu Liu
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yanxing Han
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jiandong Jiang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yuhong Wang
- State Key Laboratory of Bioactive Substances and Function of Natural Medicine, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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2
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Yang F, Zhang XL, Liu HH, Qian LL, Wang RX. Post translational modifications of connexin 43 in ventricular arrhythmias after myocardial infarction. Mol Biol Rep 2024; 51:329. [PMID: 38393658 DOI: 10.1007/s11033-024-09290-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/26/2024] [Indexed: 02/25/2024]
Abstract
Ventricular arrhythmias are the leading cause of sudden cardiac death in patients after myocardial infarction (MI). Connexin43 (Cx43) is the most important gap junction channel-forming protein in cardiomyocytes. Dysfunction of Cx43 contributes to impaired myocardial conduction and the development of ventricular arrhythmias. Following an MI, Cx43 undergoes structural remodeling, including expression abnormalities, and redistribution. These alterations detrimentally affect intercellular communication and electrical conduction within the myocardium, thereby increasing the susceptibility to post-infarction ventricular arrhythmias. Emerging evidence suggests that post-translational modifications play essential roles in Cx43 regulation after MI. Therefore, Cx43-targeted management has the potential to be a promising protective strategy for the prevention and treatment of post infarction ventricular arrhythmias. In this article, we primarily reviewed the regulatory mechanisms of Cx43 mediated post-translational modifications on post-infarction ventricular arrhythmias. Furthermore, Cx43-targeted therapy have also been discussed, providing insights into an innovative treatment strategy for ventricular arrhythmias after MI.
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Affiliation(s)
- Fan Yang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Xiao-Lu Zhang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China
| | - Huan-Huan Liu
- Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital, Wuxi Medical Center, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Nanjing Medical University, Wuxi, 214023, China.
- Wuxi School of Medicine, Jiangnan University, Wuxi, China.
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3
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Cui Z, Gu L, Liu T, Liu Y, Yu B, Kou J, Li F, Yang K. Ginsenoside Rd attenuates myocardial ischemia injury through improving mitochondrial biogenesis via WNT5A/Ca 2+ pathways. Eur J Pharmacol 2023; 957:176044. [PMID: 37660968 DOI: 10.1016/j.ejphar.2023.176044] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/05/2023]
Abstract
Ginsenoside Rd, one of the main active components in ginseng, exerts various biological activities. However, its effectiveness on myocardial ischemia injury and its potential mechanism need further clarification. The model of isoproterenol (ISO)-induced myocardial ischemia injury (MI) mice and cobalt chloride (CoCl2)-induced cardiomyocytes injury were performed. Ginsenoside Rd significantly alleviated MI injury, as evidenced by ameliorated cardiac pathological features and improved cardiac function. Simultaneously, ginsenoside Rd notably mitigated CoCl2-induced cell injury, decreased the lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) generation in vitro. Additionally, ginsenoside Rd increased nicotinamide adenine dinucleotide (NADH) and mitochondrial membrane potential (MMP). Moreover, we found that ginsenoside Rd could increase the mitochondrial DNA (mtDNA) and promote the expression of Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1α), nuclear factor erythroid 2 related factor-1 (NRF1), nuclear factor erythroid 2 related factor-2 (NRF2) and activating mitochondrial transcription factor A (TFAM), which suggested that ginsenoside Rd might accelerate mitochondrial biogenesis function to ameliorate MI injury. Importantly, ginsenoside Rd treatment significantly inhibited the WNT5A/calcium (Ca2+) signaling pathway, decreased the expression of WNT5A, Frizzled2, phosphorylated calmodulin kinase II/calmodulin kinase II (p-CaMKII/CaMKII) and the calcium overload. Meanwhile, WNT5A siRNA was further conducted to elucidate the effect of ginsenoside Rd on CoCl2-induced cardiomyocyte injury. And we found that WNT5A siRNA partially weakened the protective effects of ginsenoside Rd on mitochondrial function and mitochondrial biogenesis, suggesting that ginsenoside Rd might suppress myocardial ischemia injury through WNT5A. Overall, this study demonstrated that ginsenoside Rd could alleviate myocardial ischemia injury through improving mitochondrial biogenesis via WNT5A/Ca2+ pathways, which provided a rationale for future clinical applications and potential drugs for the treatment of cardiovascular diseases.
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Affiliation(s)
- Zekun Cui
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Lifei Gu
- NMPA Key Laboratory for Quality Research and Evaluation of Traditional Chinese Medicine, Shenzhen Institute for Drug Control, Shenzhen, China
| | - Tao Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Yining Liu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Boyang Yu
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Junping Kou
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China
| | - Fang Li
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research, Research Center for Traceability and Standardization of TCMs, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu, 211198, China.
| | - Kun Yang
- Department of Endocrinology, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, 030032, China; Department of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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4
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Teng Z, Jiang B, Wang J, Liu T, Aniagu S, Zhu Z, Chen T, Jiang Y. Regulation of Cx43 and its role in trichloroethylene-induced cardiac toxicity in H9C2 rat cardiomyocytes. CHEMOSPHERE 2023; 323:138249. [PMID: 36842555 DOI: 10.1016/j.chemosphere.2023.138249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Trichloroethylene (TCE), a widespread environmental contaminant, has been linked to congenital heart defects. Abnormal regulation of Connexin 43 is closely associated with various cardiac diseases. However, it is yet to be established how Cx43 responds to environmental pollutants. Here, we aim to explore the role of Cx43 in TCE-induced cardiac toxicity using H9C2 cardiomyocytes. EdU incorporation assay and cell cycle analysis revealed that increased number of TCE-treated cells entered into the S stage, indicating that TCE exposure provoked cell proliferation. Additionally, compromised mitochondrial function was observed in TCE-treated cells, and inhibition of mitochondrial permeability transition pore (mPTP) with Cyclosporin A or eliminating mitochondrial ROS by MitoQ alleviated the TCE-induced cardiac toxicity. Importantly, TCE exposure increased the protein expression levels of Cx43 and stimulated the recruitment of Cx43 to the mitochondria. TCE exposure disrupted canonical Wnt signal pathway, resulting in downregulation of antioxidant genes and β-catenin. The adverse effects of TCE on Wnt signal pathway activation, mitochondrial function and cell proliferation were efficiently counteracted by either Cx43 knockdown or pharmaceutical activator of Wnt signaling, CHIR-99021. Taken together, our results for the first time revealed that dysregulation of Cx43 mediates TCE-induced heart defects via mitochondrial dysfunction and Wnt signaling inhibition, suggesting that Cx43 can be a potential molecular marker or therapeutic target for cardiac diseases caused by environmental pollutants.
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Affiliation(s)
- Zhongkun Teng
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China
| | - Bin Jiang
- The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jianming Wang
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China
| | - Tiantian Liu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China
| | - Stanley Aniagu
- Toxicology, Risk Assessment, and Research Division, Texas Commission on Environmental Quality, 12015 Park 35 Cir, Austin, TX, USA
| | - Ziyu Zhu
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China
| | - Tao Chen
- School of Public Health, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China.
| | - Yan Jiang
- School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China.
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5
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Pecoraro M, Marzocco S, Belvedere R, Petrella A, Franceschelli S, Popolo A. Simvastatin Reduces Doxorubicin-Induced Cardiotoxicity: Effects beyond Its Antioxidant Activity. Int J Mol Sci 2023; 24:ijms24087573. [PMID: 37108737 PMCID: PMC10141713 DOI: 10.3390/ijms24087573] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 04/14/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
This study aimed to evaluate if Simvastatin can reduce, and/or prevent, Doxorubicin (Doxo)-induced cardiotoxicity. H9c2 cells were treated with Simvastatin (10 µM) for 4 h and then Doxo (1 µM) was added, and the effects on oxidative stress, calcium homeostasis, and apoptosis were evaluated after 20 h. Furthermore, we evaluated the effects of Simvastatin and Doxo co-treatment on Connexin 43 (Cx43) expression and localization, since this transmembrane protein forming gap junctions is widely involved in cardioprotection. Cytofluorimetric analysis showed that Simvastatin co-treatment significantly reduced Doxo-induced cytosolic and mitochondrial ROS overproduction, apoptosis, and cytochrome c release. Spectrofluorimetric analysis performed by means of Fura2 showed that Simvastatin co-treatment reduced calcium levels stored in mitochondria and restored cytosolic calcium storage. Western blot, immunofluorescence, and cytofluorimetric analyses showed that Simvastatin co-treatment significantly reduced Doxo-induced mitochondrial Cx43 over-expression and significantly increased the membrane levels of Cx43 phosphorylated on Ser368. We hypothesized that the reduced expression of mitochondrial Cx43 could justify the reduced levels of calcium stored in mitochondria and the consequent induction of apoptosis observed in Simvastatin co-treated cells. Moreover, the increased membrane levels of Cx43 phosphorylated on Ser368, which is responsible for the closed conformational state of the gap junction, let us to hypothesize that Simvastatin leads to cell-to-cell communication interruption to block the propagation of Doxo-induced harmful stimuli. Based on these results, we can conclude that Simvastatin could be a good adjuvant in Doxo anticancer therapy. Indeed, we confirmed its antioxidant and antiapoptotic activity, and, above all, we highlighted that Simvastatin interferes with expression and cellular localization of Cx43 that is widely involved in cardioprotection.
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Affiliation(s)
- Michela Pecoraro
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
| | - Stefania Marzocco
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
| | | | - Antonello Petrella
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
| | | | - Ada Popolo
- Department of Pharmacy, University of Salerno, 84084 Fisciano, SA, Italy
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6
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Boengler K, Leybaert L, Ruiz-Meana M, Schulz R. Connexin 43 in Mitochondria: What Do We Really Know About Its Function? Front Physiol 2022; 13:928934. [PMID: 35860665 PMCID: PMC9289461 DOI: 10.3389/fphys.2022.928934] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/26/2022] [Indexed: 01/04/2023] Open
Abstract
Connexins are known for their ability to mediate cell-cell communication via gap junctions and also form hemichannels that pass ions and molecules over the plasma membrane when open. Connexins have also been detected within mitochondria, with mitochondrial connexin 43 (Cx43) being the best studied to date. In this review, we discuss evidence for Cx43 presence in mitochondria of cell lines, primary cells and organs and summarize data on its localization, import and phosphorylation status. We further highlight the influence of Cx43 on mitochondrial function in terms of respiration, opening of the mitochondrial permeability transition pore and formation of reactive oxygen species, and also address the presence of a truncated form of Cx43 termed Gja1-20k. Finally, the role of mitochondrial Cx43 in pathological conditions, particularly in the heart, is discussed.
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Affiliation(s)
- Kerstin Boengler
- Institute of Physiology, Justus-Liebig University, Giessen, Germany
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences—Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Marisol Ruiz-Meana
- Cardiovascular Diseases Research Group, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Barcelona, Spain
| | - Rainer Schulz
- Institute of Physiology, Justus-Liebig University, Giessen, Germany
- *Correspondence: Rainer Schulz,
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Zhang M, Qi J, He Q, Ma D, Li J, Chu X, Zuo S, Zhang Y, Li L, Chu L. Liquiritigenin protects against myocardial ischemic by inhibiting oxidative stress, apoptosis, and L-type Ca 2+ channels. Phytother Res 2022; 36:3619-3631. [PMID: 35747908 DOI: 10.1002/ptr.7528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/06/2022] [Accepted: 06/09/2022] [Indexed: 12/07/2022]
Abstract
Liquiritigenin (Lq) offers cytoprotective effects against various cardiac injuries, but its beneficial effects on myocardial ischemic (MI) injury and the related mechanisms remain unclear. In the in vivo study, an animal model of MI was induced by intraperitoneal injection of isoproterenol (Iso, 85 mg/kg). ECG, heart rate, serum levels of CK and CK-MB, histopathological changes, and reactive oxygen species (ROS) levels were all measured. In vitro, H9c2 cells were divided into four groups and treated for 24 hr with liquiritigenin (30 μmol/L and 100 μmol/L) followed with CoCl2 (800 μmol/L) for another 24 hr. Cell viability, apoptosis, mitochondrial membrane potential, and intracellular Ca2+ concentration ([Ca2+ ]i ) were then assessed. The L-type Ca2+ current (ICa-L ) was detected using a patch clamp technique on isolated rat ventricular myocytes. The myocyte contraction and Ca2+ transients were measured using an IonOptix detection system. The remarkable cardiac injury and generation of intracellular ROS induced by Iso were alleviated via treatment with Lq. CoCl2 administration induced cell apoptosis, mitochondrial dysfunction, and Ca2+ overload in H9c2; Lq reduces these deleterious effects of CoCl2 . Meanwhile, Lq blocked ICa-L in a dose-dependent manner. The half-maximal inhibitory concentration of Lq was 110.87 μmol/L. Lq reversibly reduced the amplitude of cell contraction as well as the Ca2+ transients. The results show that Lq protects against MI injury by antioxidation, antiapoptosis, counteraction mitochondrial dysfunction, and inhibition of ICa-L , thus damping intracellular Ca2+ .
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Affiliation(s)
- Muqing Zhang
- College of Integrative Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China.,Affiliated Hospital, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Jiaying Qi
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Qianqian He
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Donglai Ma
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Jing Li
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Xi Chu
- Department of Pharmacy, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Saijie Zuo
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yixin Zhang
- School of Pharmacy, Hebei University of Chinese Medicine, Shijiazhuang, China.,International Joint Research Center on Resource Utilization and Quality Evaluation of Traditional Chinese Medicine of Hebei Province, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Li Li
- School of Pharmacy, Hebei Medical University, Shijiazhuang, China
| | - Li Chu
- College of Integrative Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China.,Hebei Key Laboratory of Integrative Medicine on Liver-Kidney Patterns, Hebei University of Chinese Medicine, Shijiazhuang, China
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Pecoraro M, Marzocco S, Franceschelli S, Popolo A. Trastuzumab and Doxorubicin Sequential Administration Increases Oxidative Stress and Phosphorylation of Connexin 43 on Ser368. Int J Mol Sci 2022; 23:ijms23126375. [PMID: 35742818 PMCID: PMC9224207 DOI: 10.3390/ijms23126375] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 02/05/2023] Open
Abstract
Human epidermal growth factor receptor-2 (HER2) is overexpressed in up to 30% of breast cancer cases, causing a more aggressive tumour growth and poor prognosis. Trastuzumab, the humanized antibody targeted to HER2, increased the life expectancy of patients, but severe cardiotoxicity emerged as a long-term adverse effect. Clinical evidence highlights that Trastuzumab-induced cardiotoxicity drastically increases in association with Doxorubicin; however, the exact mechanisms involved remain incompletely understood. In order to analyse the molecular mechanisms involved and the possible adaptative responses to Trastuzumab and Doxorubicin treatment, in this study, H9c2 cardiomyoblasts were used. Results showed that Trastuzumab and Doxorubicin sequential administration in cardiomyoblast increased cytosolic and mitochondrial ROS production, intracellular calcium dysregulation, mitochondrial membrane depolarization, and the consequent apoptosis, induced by both Trastuzumab and Doxorubicin alone. Furthermore, in these conditions, we observed increased levels of Connexin43 phosphorylated on Ser368 (pCx43). Since phosphorylation on Ser368 decreases gap junction intracellular communication, thus reducing the spread of death signals to adjacent cells, we hypothesized that the increase in pCx43 could be an adaptative response implemented by cells to defend neighbouring cells by Trastuzumab and Doxorubicin sequential administration. However, the other side of the coin is the resulting conduction abnormalities.
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