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Lee YY, Ha J, Kim YS, Ramani S, Sung S, Gil ES, Choo OS, Jang JH, Choung YH. Abnormal Cholesterol Metabolism and Lysosomal Dysfunction Induce Age-Related Hearing Loss by Inhibiting mTORC1-TFEB-Dependent Autophagy. Int J Mol Sci 2023; 24:17513. [PMID: 38139347 PMCID: PMC10743727 DOI: 10.3390/ijms242417513] [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: 11/16/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Cholesterol is a risk factor for age-related hearing loss (ARHL). However, the effect of cholesterol on the organ of Corti during the onset of ARHL is unclear. We established a mouse model for the ARHL group (24 months, n = 12) and a young group (6 months, n = 12). Auditory thresholds were measured in both groups using auditory brainstem response (ABR) at frequencies of 8, 16, and 32 kHz. Subsequently, mice were sacrificed and subjected to histological analyses, including transmission electron microscopy (TEM), H&E, Sudan Black B (SBB), and Filipin staining, as well as biochemical assays such as IHC, enzymatic analysis, and immunoblotting. Additionally, mRNA extracted from both young and aged cochlea underwent RNA sequencing. To identify the mechanism, in vitro studies utilizing HEI-OC1 cells were also performed. RNA sequencing showed a positive correlation with increased expression of genes related to metabolic diseases, cholesterol homeostasis, and target of rapamycin complex 1 (mTORC1) signaling in the ARHL group as compared to the younger group. In addition, ARHL tissues exhibited increased cholesterol and lipofuscin aggregates in the organ of Corti, lateral walls, and spiral ganglion neurons. Autophagic flux was inhibited by the accumulation of damaged lysosomes and autolysosomes. Subsequently, we observed a decrease in the level of transcription factor EB (TFEB) protein, which regulates lysosomal biosynthesis and autophagy, together with increased mTORC1 activity in ARHL tissues. These changes in TFEB and mTORC1 expression were observed in a cholesterol-dependent manner. Treatment of ARHL mice with atorvastatin, a cholesterol synthesis inhibitor, delayed hearing loss by reducing the cholesterol level and maintaining lysosomal function and autophagy by inhibiting mTORC1 and activating TFEB. The above findings were confirmed using stress-induced premature senescent House Ear Institute organ of Corti 1 (HEI-OC1) cells. The findings implicate cholesterol in the pathogenesis of ARHL. We propose that atorvastatin could prevent ARHL by maintaining lysosomal function and autophagy by inhibiting mTORC1 and activating TFEB during the aging process.
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Affiliation(s)
- Yun Yeong Lee
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
| | - Jungho Ha
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
- Department of Medical Sciences, Ajou University Graduate School of Medicine, Suwon 16499, Republic of Korea
| | - Young Sun Kim
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
| | - Sivasubramanian Ramani
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
| | - Siung Sung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
- Department of Medical Sciences, Ajou University Graduate School of Medicine, Suwon 16499, Republic of Korea
| | - Eun Sol Gil
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
- Department of Medical Sciences, Ajou University Graduate School of Medicine, Suwon 16499, Republic of Korea
| | - Oak-Sung Choo
- Department of Otorhinolaryngology-Head and Neck Surgery, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul 07441, Republic of Korea;
| | - Jeong Hun Jang
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon 16499, Republic of Korea; (Y.Y.L.); (J.H.); (Y.S.K.); (S.R.); (S.S.); (J.H.J.)
- Department of Medical Sciences, Ajou University Graduate School of Medicine, Suwon 16499, Republic of Korea
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Sparta B, Kosaisawe N, Pargett M, Patankar M, DeCuzzi N, Albeck JG. Continuous sensing of nutrients and growth factors by the mTORC1-TFEB axis. eLife 2023; 12:e74903. [PMID: 37698461 PMCID: PMC10547473 DOI: 10.7554/elife.74903] [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: 10/21/2021] [Accepted: 09/11/2023] [Indexed: 09/13/2023] Open
Abstract
mTORC1 senses nutrients and growth factors and phosphorylates downstream targets, including the transcription factor TFEB, to coordinate metabolic supply and demand. These functions position mTORC1 as a central controller of cellular homeostasis, but the behavior of this system in individual cells has not been well characterized. Here, we provide measurements necessary to refine quantitative models for mTORC1 as a metabolic controller. We developed a series of fluorescent protein-TFEB fusions and a multiplexed immunofluorescence approach to investigate how combinations of stimuli jointly regulate mTORC1 signaling at the single-cell level. Live imaging of individual MCF10A cells confirmed that mTORC1-TFEB signaling responds continuously to individual, sequential, or simultaneous treatment with amino acids and the growth factor insulin. Under physiologically relevant concentrations of amino acids, we observe correlated fluctuations in TFEB, AMPK, and AKT signaling that indicate continuous activity adjustments to nutrient availability. Using partial least squares regression modeling, we show that these continuous gradations are connected to protein synthesis rate via a distributed network of mTORC1 effectors, providing quantitative support for the qualitative model of mTORC1 as a homeostatic controller and clarifying its functional behavior within individual cells.
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Affiliation(s)
- Breanne Sparta
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Nont Kosaisawe
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Michael Pargett
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Madhura Patankar
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Nicholaus DeCuzzi
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - John G Albeck
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
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Xiong J, Luu TTT, Venkatachalam K, Du G, Zhu MX. Glutamine Produces Ammonium to Tune Lysosomal pH and Regulate Lysosomal Function. Cells 2022; 12:cells12010080. [PMID: 36611873 PMCID: PMC9819001 DOI: 10.3390/cells12010080] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/21/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Glutamine is one of the most abundant amino acids in the cell. In mitochondria, glutaminases 1 and 2 (GLS1/2) hydrolyze glutamine to glutamate, which serves as the precursor of multiple metabolites. Here, we show that ammonium generated during GLS1/2-mediated glutaminolysis regulates lysosomal pH and in turn lysosomal degradation. In primary human skin fibroblasts BJ cells and mouse embryonic fibroblasts, deprivation of total amino acids for 1 h increased lysosomal degradation capacity as shown by the increased turnover of lipidated microtubule-associated proteins 1A/1B light chain 3B (LC3-II), several autophagic receptors, and endocytosed DQ-BSA. Removal of glutamine but not any other amino acids from the culture medium enhanced lysosomal degradation similarly as total amino acid starvation. The presence of glutamine in regular culture media increased lysosomal pH by >0.5 pH unit and the removal of glutamine caused lysosomal acidification. GLS1/2 knockdown, GLS1 antagonist, or ammonium scavengers reduced lysosomal pH in the presence of glutamine. The addition of glutamine or NH4Cl prevented the increase in lysosomal degradation and curtailed the extension of mTORC1 function during the early time period of amino acid starvation. Our findings suggest that glutamine tunes lysosomal pH by producing ammonium, which regulates lysosomal degradation to meet the demands of cellular activities. During the early stage of amino acid starvation, the glutamine-dependent mechanism allows more efficient use of internal reserves and endocytosed proteins to extend mTORC1 activation such that the normal anabolism is not easily interrupted by a brief disruption of the amino acid supply.
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Affiliation(s)
- Jian Xiong
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Thi Thu Trang Luu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Kartik Venkatachalam
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Program in Neuroscience, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Guangwei Du
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Program in Neuroscience, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Correspondence: ; Tel.: +1-713-5007505
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Tan A, Prasad R, Lee C, Jho EH. Past, present, and future perspectives of transcription factor EB (TFEB): mechanisms of regulation and association with disease. Cell Death Differ 2022; 29:1433-1449. [PMID: 35739255 PMCID: PMC9345944 DOI: 10.1038/s41418-022-01028-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 12/16/2022] Open
Abstract
Transcription factor EB (TFEB), a member of the MiT/TFE family of basic helix-loop-helix leucine zipper transcription factors, is an established central regulator of the autophagy/lysosomal-to-nucleus signaling pathway. Originally described as an oncogene, TFEB is now widely known as a regulator of various processes, such as energy homeostasis, stress response, metabolism, and autophagy-lysosomal biogenesis because of its extensive involvement in various signaling pathways, such as mTORC1, Wnt, calcium, and AKT signaling pathways. TFEB is also implicated in various human diseases, such as lysosomal storage disorders, neurodegenerative diseases, cancers, and metabolic disorders. In this review, we present an overview of the major advances in TFEB research over the past 30 years, since its description in 1990. This review also discusses the recently discovered regulatory mechanisms of TFEB and their implications for human diseases. We also summarize the moonlighting functions of TFEB and discuss future research directions and unanswered questions in the field. Overall, this review provides insight into our understanding of TFEB as a major molecular player in human health, which will take us one step closer to promoting TFEB from basic research into clinical and regenerative applications.
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Affiliation(s)
- Anderson Tan
- Department of Life Science, University of Seoul, Seoul, 02504, Republic of Korea
| | - Renuka Prasad
- Department of Life Science, University of Seoul, Seoul, 02504, Republic of Korea
| | - Chaerin Lee
- Department of Life Science, University of Seoul, Seoul, 02504, Republic of Korea
| | - Eek-Hoon Jho
- Department of Life Science, University of Seoul, Seoul, 02504, Republic of Korea.
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Asrani K, Murali S, Lam B, Na CH, Phatak P, Sood A, Kaur H, Khan Z, Noë M, Anchoori RK, Talbot CC, Smith B, Skaro M, Lotan TL. mTORC1 feedback to AKT modulates lysosomal biogenesis through MiT/TFE regulation. J Clin Invest 2020; 129:5584-5599. [PMID: 31527310 DOI: 10.1172/jci128287] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 09/10/2019] [Indexed: 01/02/2023] Open
Abstract
The microphthalmia family of transcription factors (MiT/TFEs) controls lysosomal biogenesis and is negatively regulated by the nutrient sensor mTORC1. However, the mechanisms by which cells with constitutive mTORC1 signaling maintain lysosomal catabolism remain to be elucidated. Using the murine epidermis as a model system, we found that epidermal Tsc1 deletion resulted in a phenotype characterized by wavy hair and curly whiskers, and was associated with increased EGFR and HER2 degradation. Unexpectedly, constitutive mTORC1 activation with Tsc1 loss increased lysosomal content via upregulated expression and activity of MiT/TFEs, whereas genetic deletion of Rheb or Rptor or prolonged pharmacologic mTORC1 inactivation had the reverse effect. This paradoxical increase in lysosomal biogenesis by mTORC1 was mediated by feedback inhibition of AKT, and a resulting suppression of AKT-induced MiT/TFE downregulation. Thus, inhibiting hyperactive AKT signaling in the context of mTORC1 loss-of-function fully restored MiT/TFE expression and activity. These data suggest that signaling feedback loops work to restrain or maintain cellular lysosomal content during chronically inhibited or constitutively active mTORC1 signaling, respectively, and reveal a mechanism by which mTORC1 regulates upstream receptor tyrosine kinase signaling.
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Affiliation(s)
| | | | | | - Chan-Hyun Na
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Pornima Phatak
- Baltimore Veteran Affairs Medical Center, Baltimore, Maryland, USA
| | | | | | | | | | | | | | - Barbara Smith
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Sun P, Mao X, Gao M, Huang M, Chen L, Ruan G, Huang W, Braicu EI, Sehouli J. Novel endocrine therapeutic strategy in endometrial carcinoma targeting estrogen-related receptor α by XCT790 and siRNA. Cancer Manag Res 2018; 10:2521-2535. [PMID: 30127640 PMCID: PMC6089116 DOI: 10.2147/cmar.s168043] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose To explore the targeted therapy of estrogen-related receptor α (ERRα) in endometrial cancer (EC) cells and its potential mechanisms. Methods The mRNA and protein expression levels of ERRα and estrogen receptor α (ERα) were detected by qPCR and Western blotting in RL-952, AN3-CA, HEC-1A, and HEC-1B EC cell lines. After treatment with the ERRα-specific antagonist XCT790 or infection with lentivirus-mediated small interfering RNA (siRNA) targeting the ERRα (siRNA-ERRα), cell proliferation and apoptosis were evaluated by MTS assay and flow cytometry. After treatment with siRNA-ERRα, the expression profiles of transcription factors (TFs) were analyzed by protein/DNA arrays in EC cells. Results The relative mRNA levels of ERRa in RL-952 (1±0.0831) and AN3-CA (1.162±0.0325) were significantly higher than those in HEC-1A (0.3081±0.0339) and HEC-1B (0.1119±0.0091) (P<0.05), and similar results were observed for ERRα protein levels. A higher ratio of ERa/ERRa was observed in ERα-positive RL-952 (10-fold) and ANC-3A (8.5-fold) cells, whereas a lower ratio was observed in ERα-negative HEC-1A (3.75-fold) and HEC-1B cells (0-fold). Both – exogenous XCT790 and endogenous siRNA-ERRα – can decrease the expression of ERRα, thereby inhibiting proliferation but promoting apoptosis in both ERα-positive and -negative EC cells. The XCT790 presented higher proliferation-inhibition and apoptosis rates in the ERα-positive than ERα-negative cells, whereas the siRNA-ERRα exhibited higher proliferation-inhibition and apoptosis rates in the ERα-negative than in ERα-positive cells. In total, 3 upregulated and 17 downregulated TFs were screened out by knocked-down expression of ERRα in all EC cells. Among them, the upregulated TFs organic cation transporter 3/4(Oct3/4), hepatic nuclear factor 4 (HNF4), HNF4 and chicken ovalbumin upstream TF (COUP-TF) as well as downregulated transcription factor EB (TFEB) were found to be statistically significant (P<0.05). Conclusion Targeting ERRα provides a promising novel endocrine therapeutic strategy.
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Affiliation(s)
- PengMing Sun
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - XiaoDan Mao
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - Min Gao
- Department of Gynecology Oncology, Beijing Cancer Hospital, Beijing 100142, People's Republic of China
| | - MeiMei Huang
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - LiLi Chen
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - GuanYu Ruan
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - WeiYi Huang
- Laboratory of Gynecologic Oncology, Fujian Provincial Maternity and Children's Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, People's Republic of China,
| | - Elena Ioana Braicu
- Department of Gynecology, Campus Virchow Clinic, Charité Medical University Berlin, Berlin, Germany
| | - Jalid Sehouli
- Department of Gynecology, Campus Virchow Clinic, Charité Medical University Berlin, Berlin, Germany
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Lysine-specific demethylase LSD1 regulates autophagy in neuroblastoma through SESN2-dependent pathway. Oncogene 2017; 36:6701-6711. [PMID: 28783174 PMCID: PMC5717079 DOI: 10.1038/onc.2017.267] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/12/2017] [Accepted: 06/27/2017] [Indexed: 12/11/2022]
Abstract
Autophagy is a physiological process, important for recycling of macromolecules and maintenance of cellular homeostasis. Defective autophagy is associated with tumorigenesis and has a causative role in chemotherapy resistance in leukemia and in solid cancers. Here, we report that autophagy is regulated by the lysine-specific demethylase LSD1/KDM1A, an epigenetic marker whose overexpression is a feature of malignant neoplasia with an instrumental role in cancer development. In the present study, we determine that two different LSD1 inhibitors (TCP and SP2509) as well as selective ablation of LSD1 expression promote autophagy in neuroblastoma cells. At a mechanistic level, we show that LSD1 binds to the promoter region of Sestrin2 (SESN2), a critical regulator of mTORC1 activity. Pharmacological inhibition of LSD1 triggers SESN2 expression that hampers mTORC1 activity, leading to enhanced autophagy. SESN2 overexpression suffices to promote autophagy in neuroblastoma cells, while loss of SESN2 expression reduces autophagy induced by LSD1 inhibition. Our findings elucidate a mechanism whereby LSD1 controls autophagy in neuroblastoma cells through SESN2 transcription regulation, and we suggest that pharmacological targeting of LSD1 may have effective therapeutic relevance in the control of autophagy in neuroblastoma.
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Ugolino J, Ji YJ, Conchina K, Chu J, Nirujogi RS, Pandey A, Brady NR, Hamacher-Brady A, Wang J. Loss of C9orf72 Enhances Autophagic Activity via Deregulated mTOR and TFEB Signaling. PLoS Genet 2016; 12:e1006443. [PMID: 27875531 PMCID: PMC5119725 DOI: 10.1371/journal.pgen.1006443] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 10/21/2016] [Indexed: 12/13/2022] Open
Abstract
The most common cause of the neurodegenerative diseases amyotrophic lateral sclerosis and frontotemporal dementia is a hexanucleotide repeat expansion in C9orf72. Here we report a study of the C9orf72 protein by examining the consequences of loss of C9orf72 functions. Deletion of one or both alleles of the C9orf72 gene in mice causes age-dependent lethality phenotypes. We demonstrate that C9orf72 regulates nutrient sensing as the loss of C9orf72 decreases phosphorylation of the mTOR substrate S6K1. The transcription factor EB (TFEB), a master regulator of lysosomal and autophagy genes, which is negatively regulated by mTOR, is substantially up-regulated in C9orf72 loss-of-function animal and cellular models. Consistent with reduced mTOR activity and increased TFEB levels, loss of C9orf72 enhances autophagic flux, suggesting that C9orf72 is a negative regulator of autophagy. We identified a protein complex consisting of C9orf72 and SMCR8, both of which are homologous to DENN-like proteins. The depletion of C9orf72 or SMCR8 leads to significant down-regulation of each other’s protein level. Loss of SMCR8 alters mTOR signaling and autophagy. These results demonstrate that the C9orf72-SMCR8 protein complex functions in the regulation of metabolism and provide evidence that loss of C9orf72 function may contribute to the pathogenesis of relevant diseases. C9orf72 is one of many uncharacterized genes in the human genome. The presence of repeated nucleotides in the non-coding region of the C9orf72 gene (GGGGCC) has been linked to the neurodegenerative diseases Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal dementia (FTD). However, how the presence of these repeats in the gene leads to neurodegeneration is unknown. One possible explanation is that the repeats lead to a reduced expression of the C9orf72 gene and loss of function of the C9orf72 protein. Although C9orf72 is well-conserved among multi-cellular organisms, its protein function remains to be determined. In this study, we demonstrated that loss of C9orf72 reduces mTOR signaling and enhances autophagy. mTOR signaling and autophagy are important for the cellular maintenance of metabolic balances, especially under stress conditions. C9orf72 protein exists in a complex with another DENN-like protein, SMCR8, which also regulates mTOR signaling and autophagy. We generated mice lacking C9orf72, which died prematurely and showed dramatic upregulation of TFEB, a crucial transcriptional regulator of autophagy and lysosomal genes, that integrates mTOR activity state and autophagic capacity. We propose that C9orf72 function is important for metabolic control and its deficiency can contribute to the development of neurodegenerative diseases.
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Affiliation(s)
- Janet Ugolino
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yon Ju Ji
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Karen Conchina
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Justin Chu
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Raja Sekhar Nirujogi
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
| | - Akhilesh Pandey
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
| | - Nathan R. Brady
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Maryland, United States of America
| | - Anne Hamacher-Brady
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Maryland, United States of America
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, and Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail:
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Kim D, Hwang HY, Kim JY, Lee JY, Yoo JS, Marko-Varga G, Kwon HJ. FK506, an Immunosuppressive Drug, Induces Autophagy by Binding to the V-ATPase Catalytic Subunit A in Neuronal Cells. J Proteome Res 2016; 16:55-64. [PMID: 28056508 DOI: 10.1021/acs.jproteome.6b00638] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The drug FK506 (tacrolimus, fujimycin) exerts its immunosuppressive effects by regulating the nuclear factor of the activated T-cell (NFAT) family of transcription factors. However, FK506 also exhibits neuroprotective effects, but its direct target proteins that mediate these effects have not been determined. To identify the target proteins responsible for FK506's neuroprotective effects, the drug affinity responsive target stability (DARTS) method was performed using label-free FK506, and LC-MS/MS analysis of the FK506-treated proteome was also performed. Using DARTS and LC-MS/MS analyses in combination with reference studies, V-ATPase catalytic subunit A (ATP6V1A) was identified as a new target protein of FK506. The biological relevance of ATP6V1A in mediating the neuroprotective effects of FK506 was validated by analyzing FK506 activity with respect to autophagy via acridine orange staining and transcription factor EB (TFEB) translocation assay. These analyses demonstrated that the binding of FK506 with ATP6V1A induces autophagy by activating the translocation of TFEB from the cytosol into the nucleus. Because autophagy has been identified as a mechanism for treating neurodegenerative diseases and because we have demonstrated that FK506 induces autophagy, this study demonstrates that FK506 is a possible new therapy for treating neurodegenerative diseases.
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Affiliation(s)
- Dongyoung Kim
- Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University , Seoul 120-749, Korea
| | - Hui-Yun Hwang
- Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University , Seoul 120-749, Korea
| | - Jin Young Kim
- Biomedical Omics Group, Korea Basic Science Institute , Ochang, Chungbuk 28119, Korea
| | - Ju Yeon Lee
- Biomedical Omics Group, Korea Basic Science Institute , Ochang, Chungbuk 28119, Korea
| | - Jong Shin Yoo
- Biomedical Omics Group, Korea Basic Science Institute , Ochang, Chungbuk 28119, Korea
| | - György Marko-Varga
- Clinical Protein Science & Imaging, Biomedical Center, Department of Biomedical Engineering, Lund University , BMC D13, SE-221 84 Lund, Sweden
| | - Ho Jeong Kwon
- Global Research Laboratory, Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University , Seoul 120-749, Korea.,Department of Internal Medicine, College of Medicine, Yonsei University , Seoul 120-752, Korea
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