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Varela YR, Iriondo MN, Goñi FM, Alonso A, Montes LR. Ceramide regulation of autophagy: A biophysical approach. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159444. [PMID: 38056762 DOI: 10.1016/j.bbalip.2023.159444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/08/2023]
Abstract
Specific membrane lipids play unique roles in (macro)autophagy. Those include phosphatidylethanolamine, to which LC3/GABARAP autophagy proteins become covalently bound in the process, or cardiolipin, an important effector in mitochondrial autophagy (or mitophagy). Ceramide (Cer), or N-acyl sphingosine, is one of the simplest sphingolipids, known as a stress signal in the apoptotic pathway. Moreover, Cer is increasingly being recognized as an autophagy activator, although its mechanism of action is unclear. In the present review, the proposed Cer roles in autophagy are summarized, together with some biophysical properties of Cer in membranes. Possible pathways for Cer activation of autophagy are discussed, including specific protein binding of the lipid, and Cer-dependent perturbation of bilayer properties. Cer generation of lateral inhomogeneities (domain formation) is given special attention. Recent biophysical results, including fluorescence and atomic force microscopy data, show Cer-promoted enhanced binding of LC3/GABARAP to lipid bilayers. These observations could be interpreted in terms of the putative formation of Cer-rich nanodomains.
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Affiliation(s)
- Yaiza R Varela
- Instituto Biofisika (UPV/EHU, CSIC) and Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain
| | - Marina N Iriondo
- Instituto Biofisika (UPV/EHU, CSIC) and Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain
| | - Félix M Goñi
- Instituto Biofisika (UPV/EHU, CSIC) and Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain
| | - Alicia Alonso
- Instituto Biofisika (UPV/EHU, CSIC) and Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain.
| | - L Ruth Montes
- Instituto Biofisika (UPV/EHU, CSIC) and Departamento de Bioquímica, Universidad del País Vasco, 48940 Leioa, Spain
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Bao HN, Yin J, Wang LY, Wang RH, Huang LQ, Chen YL, Wu JX, Sun JQ, Liu WW, Yao N, Li J. Aberrant accumulation of ceramides in mitochondria triggers cell death by inducing autophagy in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1314-1330. [PMID: 38069660 DOI: 10.1093/jxb/erad456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/05/2023] [Indexed: 02/29/2024]
Abstract
Sphingolipids are membrane lipids and play critical roles in signal transduction. Ceramides are central components of sphingolipid metabolism that are involved in cell death. However, the mechanism of ceramides regulating cell death in plants remains unclear. Here, we found that ceramides accumulated in mitochondria of accelerated cell death 5 mutant (acd5), and expression of mitochondrion-localized ceramide kinase (ACD5) suppressed mitochondrial ceramide accumulation and the acd5 cell death phenotype. Using immuno-electron microscopy, we observed hyperaccumulation of ceramides in acer acd5 double mutants, which are characterized by mutations in both ACER (alkaline ceramidase) and ACD5 genes. The results confirmed that plants with specific ceramide accumulation exhibited localization of ceramides to mitochondria, resulting in an increase in mitochondrial reactive oxygen species production. Interestingly, when compared with the wild type, autophagy-deficient mutants showed stronger resistance to ceramide-induced cell death. Lipid profiling analysis demonstrated that plants with ceramide accumulation exhibited a significant increase in phosphatidylethanolamine levels. Furthermore, exogenous ceramide treatment or endogenous ceramide accumulation induces autophagy. When exposed to exogenous ceramides, an increase in the level of the autophagy-specific ubiquitin-like protein, ATG8e, associated with mitochondria, where it directly bound to ceramides. Taken together, we propose that the accumulation of ceramides in mitochondria can induce cell death by regulating autophagy.
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Affiliation(s)
- He-Nan Bao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Jian Yin
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
- College of JunCao Science and Ecology and Center for Horticultural Biology and Metabolomics, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - Ling-Yan Wang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Rui-Hua Wang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Li-Qun Huang
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Yi-Li Chen
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Jian-Xin Wu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Jia-Qi Sun
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Wei-Wei Liu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Nan Yao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Jian Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, P. R. China
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
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Chen C, Tang X, Lan Z, Chen W, Su H, Li W, Li Y, Zhou X, Gao H, Feng X, Guo Y, Yao M, Deng W. GABAergic signaling abnormalities in a novel CLU mutation Alzheimer's disease mouse model. Transl Res 2023; 260:32-45. [PMID: 37211336 DOI: 10.1016/j.trsl.2023.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/23/2023]
Abstract
The CLU rs11136000C mutation (CLUC) is the third most common risk factor for Alzheimer's disease (AD). However, the mechanism by which CLUC leads to abnormal GABAergic signaling in AD is unclear. To address this question, this study establishes the first chimeric mouse model of CLUC AD. Examination of grafted CLUC medial ganglionic eminence progenitors (CLUC hiMGEs) revealed increased GAD65/67 and a high frequency of spontaneous releasing events. CLUC hiMGEs also impaired cognition in chimeric mice and caused AD-related pathologies. The expression of GABA A receptor, subunit alpha 2 (Gabrα2) was higher in chimeric mice. Interestingly, cognitive impairment in chimeric mice was reversed by treatment with pentylenetetrazole, which is a GABA A receptor inhibitor. Taken together, these findings shed light on the pathogenesis of CLUC AD using a novel humanized animal model and suggest sphingolipid signaling over-activation as a potential mechanism of GABAergic signaling disorder.
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Affiliation(s)
- Chunxia Chen
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China; Department of pharmacy, The People's Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, Guangxi P. R. China
| | - Xihe Tang
- Department of neurosurgery, The People's Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, Guangxi P. R. China; Department of neurosurgery, Aviation General Hospital, Beijing, P. R. China
| | - Zhaohui Lan
- Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Bio-X Institutes, Institute of Psychology and Behavioral Sciences, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Wan Chen
- Department of Emergency, The People's Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, Guangxi, P. R. China
| | - Hua Su
- Department of Pharmacology, Guangxi Institute of Chinese Medicine & Pharmaceutical Science, Nanning, P. R. China
| | - Weidong Li
- Key Laboratory for the Genetics of Development and Neuropsychiatric Disorders (Ministry of Education), Shanghai Key Laboratory of Psychotic Disorders, and Brain Science and Technology Research Center, Bio-X Institutes, Institute of Psychology and Behavioral Sciences, Shanghai Jiao Tong University, Shanghai, P. R. China
| | - Yaoxuan Li
- Department of Neurology, The People's Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, Guangxi, P. R. China
| | - Xing Zhou
- Department of pharmacy, The People's Hospital of Guangxi Zhuang Autonomous Region & Guangxi Academy of Medical Sciences, Nanning, Guangxi P. R. China
| | - Hong Gao
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China
| | - Xinwei Feng
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China
| | - Ying Guo
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China
| | - Meicun Yao
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China
| | - Wenbin Deng
- School of Pharmaceutical Sciences, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong P. R. China.
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Lipids in Mitochondrial Macroautophagy: Phase Behavior of Bilayers Containing Cardiolipin and Ceramide. Int J Mol Sci 2023; 24:ijms24065080. [PMID: 36982156 PMCID: PMC10049649 DOI: 10.3390/ijms24065080] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 03/09/2023] Open
Abstract
Cardiolipin (CL) is a key lipid for damaged mitochondrial recognition by the LC3/GABARAP human autophagy proteins. The role of ceramide (Cer) in this process is unclear, but CL and Cer have been proposed to coexist in mitochondria under certain conditions. Varela et al. showed that in model membranes composed of egg sphingomyelin (eSM), dioleoyl phosphatidylethanolamine (DOPE), and CL, the addition of Cer enhanced the binding of LC3/GABARAP proteins to bilayers. Cer gave rise to lateral phase separation of Cer-rich rigid domains but protein binding took place mainly in the fluid continuous phase. In the present study, a biophysical analysis of bilayers composed of eSM, DOPE, CL, and/or Cer was attempted to understand the relevance of this lipid coexistence. Bilayers were studied by differential scanning calorimetry, confocal fluorescence microscopy, and atomic force microscopy. Upon the addition of CL and Cer, one continuous phase and two segregated ones were formed. In bilayers with egg phosphatidylcholine instead of eSM, in which the binding of LC3/GABARAP proteins hardly increased with Cer in the former study, a single segregated phase was formed. Assuming that phase separation at the nanoscale is ruled by the same principles acting at the micrometer scale, it is proposed that Cer-enriched rigid nanodomains, stabilized by eSM:Cer interactions formed within the DOPE- and CL-enriched fluid phase, result in structural defects at the rigid/fluid nanointerfaces, thus hypothetically facilitatingLC3/GABARAP protein interaction.
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