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Fan RZ, Sportelli C, Lai Y, Salehe SS, Pinnell JR, Brown HJ, Richardson JR, Luo S, Tieu K. A partial Drp1 knockout improves autophagy flux independent of mitochondrial function. Mol Neurodegener 2024; 19:26. [PMID: 38504290 PMCID: PMC10953112 DOI: 10.1186/s13024-024-00708-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 02/07/2024] [Indexed: 03/21/2024] Open
Abstract
BACKGROUND Dynamin-related protein 1 (Drp1) plays a critical role in mitochondrial dynamics. Partial inhibition of this protein is protective in experimental models of neurological disorders such as Parkinson's disease and Alzheimer's disease. The protective mechanism has been attributed primarily to improved mitochondrial function. However, the observations that Drp1 inhibition reduces protein aggregation in such neurological disorders suggest the involvement of autophagy. To investigate this potential novel protective mechanism of Drp1 inhibition, a model with impaired autophagy without mitochondrial involvement is needed. METHODS We characterized the effects of manganese (Mn), which causes parkinsonian-like symptoms in humans, on autophagy and mitochondria by performing dose-response studies in two cell culture models (stable autophagy HeLa reporter cells and N27 rat immortalized dopamine neuronal cells). Mitochondrial function was assessed using the Seahorse Flux Analyzer. Autophagy flux was monitored by quantifying the number of autophagosomes and autolysosomes, as well as the levels of other autophagy proteins. To strengthen the in vitro data, multiple mouse models (autophagy reporter mice and mutant Drp1+/- mice and their wild-type littermates) were orally treated with a low chronic Mn regimen that was previously reported to increase α-synuclein aggregation and transmission via exosomes. RNAseq, laser captured microdissection, immunofluorescence, immunoblotting, stereological cell counting, and behavioural studies were used. RESULTS IN VITRO: data demonstrate that at low non-toxic concentrations, Mn impaired autophagy flux but not mitochondrial function and morphology. In the mouse midbrain, RNAseq data further confirmed autophagy pathways were dysregulated but not mitochondrial related genes. Additionally, Mn selectively impaired autophagy in the nigral dopamine neurons but not the nearby nigral GABA neurons. In cells with a partial Drp1-knockdown and Drp1+/- mice, Mn induced autophagic impairment was significantly prevented. Consistent with these observations, Mn increased the levels of proteinase-K resistant α-synuclein and Drp1-knockdown protected against this pathology. CONCLUSIONS This study demonstrates that improved autophagy flux is a separate mechanism conferred by Drp1 inhibition independent of its role in mitochondrial fission. Given that impaired autophagy and mitochondrial dysfunction are two prominent features of neurodegenerative diseases, the combined protective mechanisms targeting these two pathways conferred by Drp1 inhibition make this protein an attractive therapeutic target.
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Affiliation(s)
- Rebecca Z Fan
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Carolina Sportelli
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Yanhao Lai
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Said S Salehe
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Jennifer R Pinnell
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Harry J Brown
- Department of Environmental Health Sciences, Florida International University, Miami, USA
- Biomolecular Sciences Institute, Florida International University, Miami, USA
| | - Jason R Richardson
- Department of Environmental Health Sciences, Florida International University, Miami, USA
| | - Shouqing Luo
- Peninsula Schools of Medicine and Dentistry, Plymouth University, Plymouth, UK
| | - Kim Tieu
- Department of Environmental Health Sciences, Florida International University, Miami, USA.
- Biomolecular Sciences Institute, Florida International University, Miami, USA.
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Li Y, Li X, Yang Y, Li F, Chen Q, Zhao Z, Zhang N, Li H. Hepatocyte growth factor attenuates high glucose-disturbed mitochondrial dynamics in podocytes by decreasing ARF6-dependent DRP1 translocation. Biochim Biophys Acta Mol Cell Res 2024; 1871:119623. [PMID: 37913847 DOI: 10.1016/j.bbamcr.2023.119623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/03/2023]
Abstract
Diabetic nephropathy (DN), one of the most common complications of Diabetes Mellitus, is the leading cause of end-stage renal diseases worldwide. Our previous study proved that hepatocyte growth factor (HGF) alleviated renal damages in mice with type 1 Diabetes Mellitus by suppressing overproduction of reactive oxygen species (ROS) in podocytes, while the further mechanism of how HGF lessens ROS production had not been clarified yet. ADP-ribosylation factor 6 (ARF6), the member of the small GTPases superfamilies, is widely spread among epithelial cells and can be activated by the HGF/c-Met signaling. Thus, this study was aimed to explore whether HGF could function on mitochondrial homeostasis, the main resource of ROS, in podocytes exposed to diabetic conditions via ARF6 activation. Our in vivo data showed that HGF markedly ameliorated the pathological damages in kidneys of db/db mice, especially the sharp decline of podocyte number, which was mostly blocked by the ARF6 inhibitor SecinH3. Correspondingly, our in vitro data revealed that HGF protected against high glucose-induced podocyte injuries by increasing ARF6 activity. Besides, this ARF6-dependent beneficial effect of HGF on podocytes was accompanied by improved mitochondrial dynamics and declined DRP1 translocation from cytosol to mitochondria. Collectively, our findings confirm the ability of HGF maintaining mitochondrial homeostasis in diabetic podocytes via decreasing ARF6-dependent DRP1 translocation and shed light on the novel mechanism of HGF treatment for DN.
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Affiliation(s)
- Yankun Li
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xue Li
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yuling Yang
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Fengxia Li
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Qi Chen
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Zhonghua Zhao
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Nong Zhang
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Hui Li
- Department of Pathology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
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Liu Y, Zhang Y, You G, Zheng D, He Z, Guo W, Antonina K, Shukhrat Z, Ding B, Zan J, Zhang Z. Tangeretin attenuates acute lung injury in septic mice by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis. Inflamm Res 2024; 73:47-63. [PMID: 38147126 DOI: 10.1007/s00011-023-01819-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/05/2023] [Accepted: 11/06/2023] [Indexed: 12/27/2023] Open
Abstract
OBJECTIVE NLRP3 inflammasome-mediated pyroptosis of macrophage acts essential roles in the progression of sepsis-induced acute lung injury (ALI). Tangeretin (TAN), enriched in citrus fruit peel, presents anti-oxidative and anti-inflammatory effects. Here, we aimed to explore the potentially protective effect of TAN on sepsis-induced ALI, and the underlying mechanism of TAN in regulating NLRP3 inflammasome. MATERIAL AND METHODS The effect of TAN on sepsis-induced ALI and NLRP3 inflammasome-mediated pyroptosis of macrophage were examined in vivo and in vitro using a LPS-treated mice model and LPS-induced murine macrophages, respectively. The mechanism of TAN regulating the activation of NLRP3 inflammasome in sepsis-induced ALI was investigated with HE staining, Masson staining, immunofluorescent staining, ELISA, molecular docking, transmission electron microscope detection, qRT-PCR, and western blot. RESULTS TAN could evidently attenuate sepsis-induced ALI in mice, evidenced by reducing pulmonary edema, pulmonary congestion and lung interstitial fibrosis, and inhibiting macrophage infiltration in the lung tissue. Besides, TAN significantly suppressed inflammatory cytokine IL-1β and IL-18 expression in the serum or bronchoalveolar lavage fluid (BALF) samples of mice with LPS-induced ALI, and inhibited NLRP3 inflammasome-mediated pyroptosis of macrophages. Furthermore, we found TAN inhibited ROS production, preserved mitochondrial morphology, and alleviated excessive mitochondrial fission in LPS-induced ALI in mice. Through bioinformatic analysis and molecular docking, Polo-like kinase 1 (PLK1) was identified as a potential target of TAN for treating sepsis-induced ALI. Moreover, TAN significantly inhibited the reduction of PLK1 expression, AMP-activated protein kinase (AMPK) phosphorylation, and Dynamin related protein 1 (Drp1) phosphorylation (S637) in LPS-induced ALI in mice. In addition, Volasertib, a specific inhibitor of PLK1, abolished the protective effects of TAN against NLRP3 inflammasome-mediated pyroptosis of macrophage and lung injury in the cell and mice septic models. CONCLUSION TAN attenuates sepsis-induced ALI by inhibiting ROS-mediated NLRP3 inflammasome activation via regulating PLK1/AMPK/DRP1 signaling axis, and TAN is a potentially therapeutic candidate against ALI through inhibiting pyroptosis.
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Affiliation(s)
- Yuntao Liu
- State Key Laboratory of Traditional Chinese Medicine Syndrom,The second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Yuting Zhang
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Guoxing You
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Danwen Zheng
- State Key Laboratory of Traditional Chinese Medicine Syndrom,The second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Zhipeng He
- State Key Laboratory of Traditional Chinese Medicine Syndrom,The second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Wenjie Guo
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China
| | - Kim Antonina
- No. 1 Department of Internal Diseases, Samarkand State Medical University, Samarkand, Uzbekistan
| | - Ziyadullaev Shukhrat
- No. 1 Department of Internal Diseases, Samarkand State Medical University, Samarkand, Uzbekistan
| | - Banghan Ding
- State Key Laboratory of Traditional Chinese Medicine Syndrom,The second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China.
| | - Jie Zan
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Zhongde Zhang
- State Key Laboratory of Traditional Chinese Medicine Syndrom,The second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China.
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Wu D, Tan B, Sun Y, Hu Q. Cystathionine γ lyase S-sulfhydrates Drp1 to ameliorate heart dysfunction. Redox Biol 2022; 58:102519. [PMID: 36327794 PMCID: PMC9626384 DOI: 10.1016/j.redox.2022.102519] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/07/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
Hydrogen sulfide (H2S), produced by cystathionine γ lyase (CSE), is an important endogenous gasotransmitter to maintain heart function. However, the molecular mechanism for how H2S influences the mitochondrial morphology during heart failure remains poorly understood. Here, we found that CSE/H2S pathway mediated cardiac function and mitochondrial morphology through regulating dynamin related protein 1 (Drp1) activity and translocation. Mechanistically, elevation of H2S levels by CSE overexpression declined protein level, phosphorylation (Ser 616), oligomerization and GTPase activity of Drp1 by S-sulfhydration in mouse hearts. Interestingly, Drp1 S-sulfhydration directly competed with S-nitrosylation by nitric oxide at the specific cysteine 607. The non-S-sulfhydration of Drp1 mutation (C607A) attenuated the regulatory effect of H2S on Drp1 activation, mitochondrial fission and heart function. Moreover, the non-canonical role of Drp1 mediated isoprenaline-induced mitochondrial dysfunction and cardiomyocyte death through interaction with voltage-dependent anion channel 1. These results uncover that a novel mechanism that H2S S-sulfhydrated Drp1 at cysteine 607 to prevent heart failure through modulating its activity and mitochondrial translocation. Our findings also provide initial evidence demonstrating that Drp1 may be a critical regulator as well as an effective strategy for heart dysfunction.
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Affiliation(s)
- Dan Wu
- Department of Pharmacy, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065, China
| | - Bo Tan
- Laboratory of Clinical Pharmacokinetics, Institute of Clinical Pharmacology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, 200021, China
| | - Yuanyuan Sun
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong, 226011, China,Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, Shanghai, 200444, China
| | - Qingxun Hu
- Institute of Geriatrics (Shanghai University), Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong, 226011, China,Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, Shanghai, 200444, China,Corresponding author. School of Medicine Shanghai University, 716 Jinqiu Road, Research Building, Room 215, Shanghai, 200444, China.
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Yako T, Nakamura M, Otsu W, Nakamura S, Shimazawa M, Hara H. Mitochondria dynamics in the aged mice eye and the role in the RPE phagocytosis. Exp Eye Res 2021; 213:108800. [PMID: 34688622 DOI: 10.1016/j.exer.2021.108800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/30/2021] [Accepted: 10/19/2021] [Indexed: 12/15/2022]
Abstract
Aging is a predominant risk factor for various eye diseases. Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, and its etiology remains unclear. Fragmented and dysfunctional mitochondria are associated with age-related diseases. The retinal pigment epithelium (RPE), a polarized cell layer that functions in visual pigment recycling and degeneration, is suspected as the primary region site of AMD. In the present study, we investigated the relationship between mitochondrial dysfunction and RPE aging. Compared to young mice, aged pigmented mice (C57BL/6J, 12-month-old) exhibit decreased visual function without retinal thinning. Consistently, the rhodopsin expression level decreased in the outer segment of aged mice. Moreover, the cell volume of the RPE increased in aged animals. Interestingly, the expression of mitochondria dynamics-related proteins, including Drp1, was altered in the RPE-choroid complex but not in the neural retina after aging. Electron microscopy revealed that mitochondrial size decreased and cristae width increased in aged RPE. The photoreceptor outer segment (POS) treatment of ARPE-19 cells causes Drp1 activation. Furthermore, pharmacological suppression of mitochondrial fission improved the phagocytosis of the POS. These findings indicate that mitochondrial dysfunction and fission in RPE impede phagocytosis and cause retardation of the visual cycle, which can be one of the age-related defects in the retina that may contribute to the onset of AMD.
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Okada M, Morioka S, Kanazawa H, Yamawaki H. Canstatin inhibits isoproterenol-induced apoptosis through preserving mitochondrial morphology in differentiated H9c2 cardiomyoblasts. Apoptosis. 2016;21:887-895. [PMID: 27315818 DOI: 10.1007/s10495-016-1262-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Canstatin, a non-collagenous fragment, is cleaved from type IV collagen α2 chain, an essential component of basement membrane surrounding cardiomyocytes. Although canstatin is known as an endogenous anti-angiogenic factor, its effects on cardiomyocytes have not been clarified. This study examined the effects of canstatin on isoproterenol-induced apoptosis in differentiated H9c2 cardiomyoblasts. Retinoic acid was used to differentiate H9c2 myoblast to cardiomyocyte-like phenotype. Cell viability was determined by a cell counting assay. Western blotting was performed to detect expression of cleaved casepase-3 and phosphorylation of dynamin related protein (Drp)1 at Ser637 which regulates mitochondrial fission. Mito Sox Red staining was performed to examine a mitochondria-dependent production of reactive oxygen species (ROS). Mitochondrial morphology was detected by Mito Tracker Red staining. Isoproterenol (100 μM, 48 h) significantly decreased cell viability and increased cleaved caspase-3 expression, which were inhibited by canstatin (10-250 ng/ml) in a concentration-dependent manner. Canstatin suppressed the isoproterenol-induced mitochondrial fission but not ROS. Canstatin also inhibited the isoproterenol-induced dephosphorylation of Drp1 at Ser637. In conclusion, canstatin inhibits isoproterenol-induced apoptosis through the inhibition of mitochondrial fission via the suppression of dephosphorylation of Drp1 at Ser637 in differentiated H9c2 cardiomyoblasts.
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Matsuishi YI, Kato H, Masuda K, Yamaza H, Hirofuji Y, Sato H, Wada H, Kiyoshima T, Nonaka K. Accelerated dentinogenesis by inhibiting the mitochondrial fission factor, dynamin related protein 1. Biochem Biophys Res Commun 2017; 495:1655-1660. [PMID: 29223396 DOI: 10.1016/j.bbrc.2017.12.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/05/2017] [Indexed: 12/15/2022]
Abstract
Undifferentiated odontogenic epithelium and dental papilla cells differentiate into ameloblasts and odontoblasts, respectively, both of which are essential for tooth development. These differentiation processes involve dramatic functional and morphological changes of the cells. For these changes to occur, activation of mitochondrial functions, including ATP production, is extremely important. In addition, these changes are closely related to mitochondrial fission and fusion, known as mitochondrial dynamics. However, few studies have focused on the role of mitochondrial dynamics in tooth development. The purpose of this study was to clarify this role. We used mouse tooth germ organ cultures and a mouse dental papilla cell line with the ability to differentiate into odontoblasts, in combination with knockdown of the mitochondrial fission factor, dynamin related protein (DRP)1. In organ cultures of the mouse first molar, tooth germ developed to the early bell stage. The amount of dentin formed under DRP1 inhibition was significantly larger than that of the control. In experiments using a mouse dental papilla cell line, differentiation into odontoblasts was enhanced by inhibiting DRP1. This was associated with increased mitochondrial elongation and ATP production compared to the control. These results suggest that DRP1 inhibition accelerates dentin formation through mitochondrial elongation and activation. This raises the possibility that DRP1 might be a therapeutic target for developmental disorders of teeth.
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Affiliation(s)
- Yumiko I Matsuishi
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Hiroki Kato
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Keiji Masuda
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan.
| | - Haruyoshi Yamaza
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Yuta Hirofuji
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Hiroshi Sato
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Hiroko Wada
- Laboratory of Oral Pathology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Tamotsu Kiyoshima
- Laboratory of Oral Pathology, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
| | - Kazuaki Nonaka
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-Ku, Fukuoka 812-8582, Japan
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Zhang H, Wang P, Bisetto S, Yoon Y, Chen Q, Sheu SS, Wang W. A novel fission-independent role of dynamin-related protein 1 in cardiac mitochondrial respiration. Cardiovasc Res 2017; 113:160-170. [PMID: 27794519 PMCID: PMC5340145 DOI: 10.1093/cvr/cvw212] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/07/2016] [Accepted: 09/21/2016] [Indexed: 01/14/2023] Open
Abstract
AIMS Mitochondria in adult cardiomyocytes exhibit static morphology and infrequent dynamic changes, despite the high abundance of fission and fusion regulatory proteins in the heart. Previous reports have indicated that fusion proteins may bear functions beyond morphology regulation. Here, we investigated the role of fission protein, dynamin-related protein 1 (DRP1), on mitochondrial respiration regulation in adult cardiomyocytes. METHODS AND RESULTS By using genetic or pharmacological approaches, we manipulated the activity or protein level of fission and fusion proteins and found they mildly influenced mitochondrial morphology in adult rodent cardiomyocytes, which is in contrast to their significant effect in H9C2 cardiac myoblasts. Intriguingly, inhibiting endogenous DRP1 by dominant-negative DRP1 mutation (K38A), shRNA, or Mdivi-1 suppressed maximal respiration and respiratory control ratio in isolated mitochondria from adult mouse heart or in adult cardiomyocytes from rat. Meanwhile, basal respiration was increased due to increased proton leak. Facilitating mitofusin-mediated fusion by S3 compound, however, failed to inhibit mitochondrial respiration in adult cardiomyocytes. Mechanistically, DRP1 inhibition did not affect the maximal activity of individual respiratory chain complexes or the assembly of supercomplexes. Knocking out cyclophilin D, a regulator of mitochondrial permeability transition pore (mPTP), abolished the effect of DRP1 inhibition on respiration. Finally, DRP1 inhibition decreased transient mPTP-mediated mitochondrial flashes, delayed laser-induced mPTP opening and suppressed mitochondrial reactive oxygen species (ROS). CONCLUSION These results uncover a novel non-canonical function of the fission protein, DRP1 in maintaining or positively stimulating mitochondrial respiration, bioenergetics and ROS signalling in adult cardiomyocyte, which is likely independent of morphological changes.
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Affiliation(s)
- Huiliang Zhang
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, 850 Republican Street N121, Seattle, WA 98109, USA
| | - Pei Wang
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, 850 Republican Street N121, Seattle, WA 98109, USA
| | - Sara Bisetto
- Department of Medicine, Center for Translational Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust Street, Room 543D, Philadelphia, PA 19107, USA
| | - Yisang Yoon
- Department of Physiology, Georgia Regents University, 1120 Fifteenth Street, Augusta, GA 30912, USA
| | - Quan Chen
- Laboratory of Apoptosis and Mitochondrial Biology, The State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China
| | - Shey-Shing Sheu
- Department of Medicine, Center for Translational Medicine, Sidney Kimmel Medical College, Thomas Jefferson University, 1020 Locust Street, Room 543D, Philadelphia, PA 19107, USA
| | - Wang Wang
- Department of Anesthesiology and Pain Medicine, Mitochondria and Metabolism Center, University of Washington, 850 Republican Street N121, Seattle, WA 98109, USA
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