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Han X, Huang S, Zhuang Z, Zhang X, Xie M, Lou N, Hua M, Zhuang X, Yu S, Chen S. Phosphatidate phosphatase Lipin1 involves in diabetic encephalopathy pathogenesis via regulating synaptic mitochondrial dynamics. Redox Biol 2024; 69:102996. [PMID: 38103341 PMCID: PMC10770635 DOI: 10.1016/j.redox.2023.102996] [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: 11/28/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023] Open
Abstract
Diabetic encephalopathy (DE) is a common central nervous system complication of diabetes mellitus without effective therapy currently. Recent studies have highlighted synaptic mitochondrial damages as a possible pathological basis for DE, but the underlying mechanisms remain unclear. Our previous work has revealed that phosphatidate phosphatase Lipin1, a critical enzyme involved with phospholipid synthesis, is closely related to the pathogenesis of DE. Here, we demonstrate that Lipin1 is significantly down-regulated in rat hippocampus of DE. Knock-down of Lipin1 within hippocampus of normal rats induces dysregulation of homeostasis in synaptic mitochondrial dynamics with an increase of mitochondrial fission and a decrease of fusion, then causes synaptic mitochondrial dysfunction, synaptic plasticity deficits as well as cognitive impairments, similar to that observed in response to chronic hyperglycemia exposure. In contrast, an up-regulation of Lipin1 within hippocampus in the DE model ameliorates this cascade of dysfunction. We also find that the effect of Lipin1 that regulating mitochondrial dynamics results from maintaining appropriate phospholipid components in the mitochondrial membrane. In conclusion, alterations in hippocampal Lipin1 contribute to hippocampal synaptic mitochondrial dysfunction and cognitive deficits observed in DE. Targeting Lipin1 might be a potential therapeutic strategy for the clinical treatment of DE.
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Affiliation(s)
- Xiaolin Han
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China
| | - Shan Huang
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China
| | - Ziyun Zhuang
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China; Department of Endocrinology and Metabolism, First People's Hospital of Jinan, Jinan, 250011, China
| | - Xiaochen Zhang
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China; Department of Clinical Medicine, Heze Medical College, Heze, 274009, China
| | - Min Xie
- Department of Endocrinology and Metabolism, Binzhou Medical University Hospital, Binzhou, 256603, China
| | - Nengjun Lou
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China; Multidisciplinary Innovation Center for Nephrology of the Second Hospital of Shandong University, Jinan, 250033, China
| | - Mengyu Hua
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China
| | - Xianghua Zhuang
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China; Multidisciplinary Innovation Center for Nephrology of the Second Hospital of Shandong University, Jinan, 250033, China.
| | - Shuyan Yu
- Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China.
| | - Shihong Chen
- Depratment of Endocrinology and Metabolism, The Second Hospital of Shandong University, Jinan, 250033, China; Multidisciplinary Innovation Center for Nephrology of the Second Hospital of Shandong University, Jinan, 250033, China.
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Zhao Y, Chen C, Pan J, Lam SM, Shui G, Yang S, Wu T, Yang N, Tao C, Zhao J, Wang Y. Adipocyte Rnf20 ablation increases the fast-twitch fibers of skeletal muscle via lysophosphatidylcholine 16:0. Cell Mol Life Sci 2023; 80:243. [PMID: 37555936 PMCID: PMC11072846 DOI: 10.1007/s00018-023-04896-4] [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: 03/01/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/10/2023]
Abstract
Both adipose tissue and skeletal muscle are highly dynamic tissues and interact at the metabolic and hormonal levels in response to internal and external stress, and they coordinate in maintaining whole-body metabolic homeostasis. In our previous study, we revealed that adipocyte-specific Rnf20 knockout mice (ASKO mice) exhibited lower fat mass but higher lean mass, providing a good model for investigating the adipose-muscle crosstalk and exploring the effect of the adipocyte Rnf20 gene on the physiology and metabolism of skeletal muscle. Here, we confirmed that ASKO mice exhibited the significantly increased body weight and gastrocnemius muscle weight. Fiber-type switching in the soleus muscle of ASKO mice was observed, as evidenced by the increased number of fast-twitch fibers and decreased number of slow-twitch fibers. Serum metabolites with significant alteration in abundance were identified by metabolomic analysis and the elevated lysophosphatidylcholine 16:0 [LysoPC (16:0)] was observed in ASKO mice. In addition, lipidome analysis of gonadal white adipose tissue revealed a significant increase in LysoPCs and LysoPC (16:0) in ASKO mice. Furthermore, knockdown of Rnf20 gene in 3T3-L1 cells significantly increased the secretion of LysoPC, suggesting that LysoPC might be a critical metabolite in the adipose-muscle crosstalk of ASKO mice. Furthermore, in vitro study demonstrated that LysoPC (16:0) could induce the expression of fast-twitch muscle fibers related genes in differentiated C2C12 cells, indicating its potential role in adipose-muscle crosstalk. Taken together, these findings not only expand our understanding of the biological functions of Rnf20 gene in systemic lipid metabolism, but also provide insight into adipose tissue dysfunction-induced physiological alterations in skeletal muscle.
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Affiliation(s)
- Ying Zhao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Chuanhe Chen
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Jianfei Pan
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Sin Man Lam
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Guanghou Shui
- Institute of Genetics and Development Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shulin Yang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Tianwen Wu
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Ning Yang
- College of Animal Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Cong Tao
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Jianguo Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Yanfang Wang
- State Key Laboratory of Animal Biotech Breeding, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
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Papsdorf K, Miklas JW, Hosseini A, Cabruja M, Morrow CS, Savini M, Yu Y, Silva-García CG, Haseley NR, Murphy LM, Yao P, de Launoit E, Dixon SJ, Snyder MP, Wang MC, Mair WB, Brunet A. Lipid droplets and peroxisomes are co-regulated to drive lifespan extension in response to mono-unsaturated fatty acids. Nat Cell Biol 2023; 25:672-684. [PMID: 37127715 PMCID: PMC10185472 DOI: 10.1038/s41556-023-01136-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/23/2023] [Indexed: 05/03/2023]
Abstract
Dietary mono-unsaturated fatty acids (MUFAs) are linked to longevity in several species. But the mechanisms by which MUFAs extend lifespan remain unclear. Here we show that an organelle network involving lipid droplets and peroxisomes is critical for MUFA-induced longevity in Caenorhabditis elegans. MUFAs upregulate the number of lipid droplets in fat storage tissues. Increased lipid droplet number is necessary for MUFA-induced longevity and predicts remaining lifespan. Lipidomics datasets reveal that MUFAs also modify the ratio of membrane lipids and ether lipids-a signature associated with decreased lipid oxidation. In agreement with this, MUFAs decrease lipid oxidation in middle-aged individuals. Intriguingly, MUFAs upregulate not only lipid droplet number but also peroxisome number. A targeted screen identifies genes involved in the co-regulation of lipid droplets and peroxisomes, and reveals that induction of both organelles is optimal for longevity. Our study uncovers an organelle network involved in lipid homeostasis and lifespan regulation, opening new avenues for interventions to delay aging.
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Affiliation(s)
| | - Jason W Miklas
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Amir Hosseini
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Matias Cabruja
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Christopher S Morrow
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Marzia Savini
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
| | - Yong Yu
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Carlos G Silva-García
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | | | | | - Pallas Yao
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | | | - Scott J Dixon
- Department of Biology, Stanford University, Stanford, CA, USA
| | | | - Meng C Wang
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - William B Mair
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA, USA.
- Glenn Laboratories for the Biology of Aging, Stanford University, Stanford, CA, USA.
- Wu Tsai Institute of Neurosciences, Stanford University, Stanford, CA, USA.
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Chen Q, Li X, Cui J, Xu C, Wei H, Zhao Q, Yao H, You H, Zhang D, Yu H. Effects of Stocking Density on Fatty Acid Metabolism by Skeletal Muscle in Mice. Animals (Basel) 2022; 12:ani12192538. [PMID: 36230279 PMCID: PMC9559694 DOI: 10.3390/ani12192538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 08/22/2022] [Accepted: 09/18/2022] [Indexed: 11/16/2022] Open
Abstract
Specific pathogen-free (SPF) grade laboratory animals are kept in specific cages for life. The limited space could affect the characterization of colonization and dynamic changes related to gut microorganisms, and affect adipokines, even further affecting the fat synthesis and muscle quality of animals. The objective of this study was to analyze the stocking density on the dynamic distribution of gut microbiota, fat synthesis and muscle quality of SPF grade Kunming mice. Three housing densities were accomplished by raising different mice per cage with the same floor size. Kunming mice were reared at low stocking density (LSD, three mice a group), medium stocking density (MSD, 5 mice a group), and high stocking density (HSD, 10 mice a group) for 12 weeks. The results demonstrated that the stocking density affected intestinal microbial flora composition. We found that compared with the MSD group, the abundance of Lactobacillus in the LSD group and the HSD group decreased, but the abundance of unclassified_Porphyromonadaceae increased. Moreover, fat synthesis and muscle quality were linked to the intestinal microbial flora and stocking density. Compared with the LSD group and the HSD group, the MSD group had a more balanced gut flora, higher fat synthesis and higher muscle quality. Overall, this study demonstrated that stocking density could affect gut microbiota composition, and reasonable stocking density could improve fat synthesis and muscle quality. Our study will provide theoretical support for the suitable stocking density of laboratory animals.
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Affiliation(s)
- Qiuyan Chen
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Xiaohui Li
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Jiarun Cui
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Caiyun Xu
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Hongfei Wei
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Qian Zhao
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Hongli Yao
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Hailong You
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
| | - Dawei Zhang
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
- Correspondence: (D.Z.); (H.Y.); Tel.: +86-0-431-8561-9495 (H.Y.)
| | - Huimei Yu
- Center of Animal Experiment, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, Changchun 130021, China
- Correspondence: (D.Z.); (H.Y.); Tel.: +86-0-431-8561-9495 (H.Y.)
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Pintus SS, Akberdin IR, Yevshin I, Makhnovskii P, Tyapkina O, Nigmetzyanov I, Nurullin L, Devyatiyarov R, Shagimardanova E, Popov D, Kolpakov FA, Gusev O, Gazizova GR. Genome-Wide Atlas of Promoter Expression Reveals Contribution of Transcribed Regulatory Elements to Genetic Control of Disuse-Mediated Atrophy of Skeletal Muscle. BIOLOGY 2021; 10:biology10060557. [PMID: 34203013 PMCID: PMC8235325 DOI: 10.3390/biology10060557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/10/2021] [Accepted: 06/15/2021] [Indexed: 12/05/2022]
Abstract
Simple Summary The genetic process underlying the control of skeletal muscle homeostasis is a key factor in methods that develop technologies to prevent age and immobility-driven atrophy. In the current paper, using advanced methods for the whole-genome profiling of transcription starting sites in fast and slow muscle in rats, we developed an integrative database of transcribed regulatory elements. Employing methods of comparative transcriptomics, we demonstrate that cis-regulatory elements are actively involved in the control of atrophy and recovery, and that the differential use of promoters and enhancers is the one of the key mechanisms that distinguishes between specific processes in slow and fast skeletal muscles. Abstract The prevention of muscle atrophy carries with it clinical significance for the control of increased morbidity and mortality following physical inactivity. While major transcriptional events associated with muscle atrophy-recovery processes are the subject of active research on the gene level, the contribution of non-coding regulatory elements and alternative promoter usage is a major source for both the production of alternative protein products and new insights into the activity of transcription factors. We used the cap-analysis of gene expression (CAGE) to create a genome-wide atlas of promoter-level transcription in fast (m. EDL) and slow (m. soleus) muscles in rats that were subjected to hindlimb unloading and subsequent recovery. We found that the genetic regulation of the atrophy-recovery cycle in two types of muscle is mediated by different pathways, including a unique set of non-coding transcribed regulatory elements. We showed that the activation of “shadow” enhancers is tightly linked to specific stages of atrophy and recovery dynamics, with the largest number of specific regulatory elements being transcriptionally active in the muscles on the first day of recovery after a week of disuse. The developed comprehensive database of transcription of regulatory elements will further stimulate research on the gene regulation of muscle homeostasis in mammals.
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Affiliation(s)
- Sergey S. Pintus
- Laboratory of Bioinformatics, Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- BIOSOFT.RU LLC, 630058 Novosibirsk, Russia; (S.S.P.); (I.R.A.); (I.Y.)
| | - Ilya R. Akberdin
- Laboratory of Bioinformatics, Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
- BIOSOFT.RU LLC, 630058 Novosibirsk, Russia; (S.S.P.); (I.R.A.); (I.Y.)
- Faculty of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Ivan Yevshin
- Laboratory of Bioinformatics, Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- BIOSOFT.RU LLC, 630058 Novosibirsk, Russia; (S.S.P.); (I.R.A.); (I.Y.)
| | - Pavel Makhnovskii
- Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow 123007, Russia; (P.M.); (D.P.)
| | - Oksana Tyapkina
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, 420007 Kazan, Russia; (O.T.); (L.N.)
- Department of Biology, Kazan State Medical University, 420012 Kazan, Russia
| | - Islam Nigmetzyanov
- Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420009 Kazan, Russia; (I.N.); (R.D.); (E.S.)
| | - Leniz Nurullin
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, 420007 Kazan, Russia; (O.T.); (L.N.)
- Department of Biology, Kazan State Medical University, 420012 Kazan, Russia
| | - Ruslan Devyatiyarov
- Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420009 Kazan, Russia; (I.N.); (R.D.); (E.S.)
| | - Elena Shagimardanova
- Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420009 Kazan, Russia; (I.N.); (R.D.); (E.S.)
| | - Daniil Popov
- Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow 123007, Russia; (P.M.); (D.P.)
| | - Fedor A. Kolpakov
- Laboratory of Bioinformatics, Federal Research Center for Information and Computational Technologies, 630090 Novosibirsk, Russia
- Department of Computational Biology, Scientific Center for Information Technologies and Artificial Intelligence, Sirius University of Science and Technology, 354340 Sochi, Russia
- BIOSOFT.RU LLC, 630058 Novosibirsk, Russia; (S.S.P.); (I.R.A.); (I.Y.)
- Correspondence: or (F.A.K.); (O.G.); (G.R.G.)
| | - Oleg Gusev
- Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420009 Kazan, Russia; (I.N.); (R.D.); (E.S.)
- RIKEN Center for Integrative Medical Sciences, RIKEN, Yokohama, Kanagawa 230-0045, Japan
- Department of Functional Transcriptomics for Medical Genetic Diagnostics, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan
- Correspondence: or (F.A.K.); (O.G.); (G.R.G.)
| | - Guzel R. Gazizova
- Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420009 Kazan, Russia; (I.N.); (R.D.); (E.S.)
- Correspondence: or (F.A.K.); (O.G.); (G.R.G.)
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Lu S, Lyu Z, Wang Z, Kou Y, Liu C, Li S, Hu M, Zhu H, Wang W, Zhang C, Kuan YS, Liu YW, Chen J, Tian J. Lipin 1 deficiency causes adult-onset myasthenia with motor neuron dysfunction in humans and neuromuscular junction defects in zebrafish. Theranostics 2021; 11:2788-2805. [PMID: 33456573 PMCID: PMC7806489 DOI: 10.7150/thno.53330] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/12/2020] [Indexed: 12/03/2022] Open
Abstract
Lipin 1 is an intracellular protein acting as a phosphatidic acid phosphohydrolase enzyme controlling lipid metabolism. Human recessive mutations in LPIN1 cause recurrent, early-onset myoglobinuria, a condition normally associated with muscle pain and weakness. Whether and how lipin 1 deficiency in humans leads to peripheral neuropathy is yet unclear. Herein, two novel compound heterozygous mutations in LPIN1 with neurological disorders, but no myoglobinuria were identified in an adult-onset syndromic myasthenia family. The present study sought to explore the pathogenic mechanism of LPIN1 in muscular and neural development. Methods: The clinical diagnosis of the proband was compared to the known 48 cases of LPIN1 recessive homozygous mutations. Whole-exome sequencing was carried out on the syndromic myasthenia family to identify the causative gene. The pathogenesis of lipin 1 deficiency during somitogenesis and neurogenesis was investigated using the zebrafish model. Whole-mount in situ hybridization, immunohistochemistry, birefringence analysis, touch-evoke escape response and locomotion assays were performed to observe in vivo the changes in muscles and neurons. The conservatism of the molecular pathways regulated by lipin 1 was evaluated in human primary glioblastoma and mouse myoblast cells by siRNA knockdown, drug treatment, qRT-PCR and Western blotting analysis. Results: The patient exhibited adult-onset myasthenia accompanied by muscle fiber atrophy and nerve demyelination without myoglobinuria. Two novel heterozygous mutations, c.2047A>C (p.I683L) and c.2201G>A (p.R734Q) in LPIN1, were identified in the family and predicted to alter the tertiary structure of LPIN1 protein. Lipin 1 deficiency in zebrafish embryos generated by lpin1 morpholino knockdown or human LPIN1 mutant mRNA injections reproduced the myotomes defects, a reduction both in primary motor neurons and secondary motor neurons projections, morphological changes of post-synaptic clusters of acetylcholine receptors, and myelination defects, which led to reduced touch-evoked response and abnormalities of swimming behaviors. Loss of lipin 1 function in zebrafish and mammalian cells also exhibited altered expression levels of muscle and neuron markers, as well as abnormally enhanced Notch signaling, which was partially rescued by the specific Notch pathway inhibitor DAPT. Conclusions: These findings pointed out that the compound heterozygous mutations in human LPIN1 caused adult-onset syndromic myasthenia with peripheral neuropathy. Moreover, zebrafish could be used to model the neuromuscular phenotypes due to the lipin 1 deficiency, where a novel pathological role of over-activated Notch signaling was discovered and further confirmed in mammalian cell lines.
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