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Tang D, Kang R. SQSTM1 is a therapeutic target for infection and sterile inflammation. Cytokine 2023; 169:156317. [PMID: 37542833 DOI: 10.1016/j.cyto.2023.156317] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 07/31/2023] [Indexed: 08/07/2023]
Abstract
Inflammation represents a fundamental immune response triggered by various detrimental stimuli, such as infections, tissue damage, toxins, and foreign substances. Protein degradation plays a crucial role in regulating the inflammatory process at multiple levels. The identification of sequestosome 1 (SQSTM1, also known as p62) protein as a binding partner of lymphocyte-specific protein tyrosine kinase in 1995 marked a significant milestone. Subsequent investigations unveiled the activity of SQSTM1 to interact with diverse unstructured substrates, including proteins, organelles, and pathogens, facilitating their delivery to the lysosome for autophagic degradation. In addition to its well-established intracellular functions, emerging studies have reported the active secretion or passive release of SQSTM1 by immune or non-immune cells, orchestrating the inflammatory responses. These distinct characteristics render SQSTM1 a critical therapeutic target in numerous human diseases, including infectious diseases, rheumatoid arthritis, inflammatory bowel disease, pancreatitis, asthma, chronic obstructive pulmonary disease, and cardiovascular diseases. This review provides a comprehensive overview of the structure and modulation of SQSTM1, discusses its intracellular and extracellular roles in inflammation, and highlights its significance in inflammation-related diseases. Future investigations focusing on elucidating the precise localization, structure, post-translational modifications of SQSTM1, as well as the identification of additional interacting partners, hold promise for unravelling further insights into the multifaceted functions of SQSTM1.
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Affiliation(s)
- Daolin Tang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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Chen Y, Bao M, Liu JT, Bao H, Zhang SM, Lou Y, Qi YX. Defective autophagy triggered by arterial cyclic stretch promotes neointimal hyperplasia in vein grafts via the p62/nrf2/slc7a11 signaling pathway. J Mol Cell Cardiol 2022; 173:101-114. [PMID: 36308866 DOI: 10.1016/j.yjmcc.2022.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/02/2022] [Accepted: 10/11/2022] [Indexed: 11/21/2022]
Abstract
Autophagy is an adaptation mechanism to keep cellular homeostasis, and its deregulation is implicated in various cardiovascular diseases. After vein grafting, hemodynamic factors play crucial roles in neointimal hyperplasia, but the mechanisms are poorly understood. Here, we investigated the impacts of arterial cyclic stretch on autophagy of venous smooth muscle cells (SMCs) and its role in neointima formation after vein grafting. Rat jugular vein graft were generated via the 'cuff' technique. Autophagic flux in venous SMCs is impaired in 3-day, 1-week and 2-week grafted veins. 10%-1.25 Hz cyclic stretch (arterial stretch) loaded with FX5000 stretch system on venous SMCs blocks cellular autophagic flux in vitro and shows no significant impact on activity of mTORC1 and AMPK. Microtubule depolymerization but not lysosome dysfunction nor autophagosome/amphisome-lysosomal membrane fusion blockade is involved in the impairment of autophagic flux. Microtubule stabilization, induced by paclitaxel treatment and external stents intervention respectively, restores venous SMC autophagy and ameliorates neointimal hyperplasia in vivo. Moreover, autophagy impairment causes accumulation of the cargo receptor p62, which sequesters keap1 to p62 aggregates and results in the stabilization and nuclear translocation of nrf2 to modulate its target antioxidative gene SLC7A11. p62 silencing abrogates the increases of nrf2 and slc7a11 protein expression, glutathione level and venous SMC proliferation triggered by arterial cyclic stretch in vitro, and further hinders nrf2 nuclear translocation, reduces neointimal thickness after vein grafting in vivo. p62 (T349A) mutation also inhibited venous SMC proliferation and alleviated neointimal formation in vivo. These findings suggest that stabilization of microtubules to rescue autophagic flux or direct silencing of p62 are potential therapeutic strategies for neointimal hyperplasia.
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Affiliation(s)
- Yi Chen
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Min Bao
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ji-Ting Liu
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Han Bao
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shou-Min Zhang
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yue Lou
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ying-Xin Qi
- Institute of Mechanobiology & Medical Engineering, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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Bhat OM, Yuan X, Kukreja RC, Li PL. Regulatory role of mammalian target of rapamycin signaling in exosome secretion and osteogenic changes in smooth muscle cells lacking acid ceramidase gene. FASEB J 2021; 35:e21732. [PMID: 34143450 DOI: 10.1096/fj.202100385r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/22/2021] [Accepted: 06/01/2021] [Indexed: 12/28/2022]
Abstract
Acid ceramidase (murine gene code: Asah1) (50 kDa) belongs to N-terminal nucleophile hydrolase family. This enzyme is located in the lysosome, which mediates conversion of ceramide (CER) into sphingosine and free fatty acids at acidic pH. CER plays an important role in intracellular sphingolipid metabolism and its increase causes inflammation. The mammalian target of rapamycin complex 1 (mTORC1) signaling on late endosomes (LEs)/lysosomes may control cargo selection, membrane biogenesis, and exosome secretion, which may be fine controlled by lysosomal sphingolipids such as CER. This lysosomal-CER-mTOR signaling may be a crucial molecular mechanism responsible for development of arterial medial calcification (AMC). Torin-1 (5 mg/kg/day), an mTOR inhibitor, significantly decreased aortic medial calcification accompanied with decreased expression of osteogenic markers like osteopontin (OSP) and runt-related transcription factor 2 (RUNX2) and upregulation of smooth muscle 22α (SM22-α) in mice receiving high dose of Vitamin D (500 000 IU/kg/day). Asah1fl/fl /SMCre mice had markedly increased co-localization of mTORC1 with lysosome-associated membrane protein-1 (Lamp-1) (lysosome marker) and decreased co-localization of vacuolar protein sorting-associated protein 16 (VPS16) (a multivesicular bodies [MVBs] marker) with Lamp-1, suggesting mTOR activation caused reduced MVBs interaction with lysosomes. Torin-1 significantly reduced the co-localization of mTOR vs Lamp-1, increased lysosome-MVB interaction which was associated with reduced accumulation of CD63 and annexin 2 (exosome markers) in the coronary arterial wall of mice. Using coronary artery smooth muscle cells (CASMCs), Pi -stimulation significantly increased p-mTOR expression in Asah1fl/fl /SMCre CASMCs as compared to WT/WT cells associated with increased calcium deposition and mineralization. Torin-1 blocked Pi -induced calcium deposition and mineralization. siRNA mTOR and Torin-1 significantly reduce co-localization of mTORC1 with Lamp-1, increased VPS16 vs Lamp-1 co-localization in Pi -stimulated CASMCs, associated with decreased exosome release. Functionally, Torin-1 significantly reduces arterial stiffening as shown by restoration from increased pulse wave velocity and decreased elastin breaks. These results suggest that lysosomal CER-mTOR signaling may play a critical role for the control of lysosome-MVB interaction, exosome secretion and arterial stiffening during AMC.
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Affiliation(s)
- Owais M Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Xinxu Yuan
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Rakesh C Kukreja
- VCU Pauley Heart Center, Division of Cardiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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Dexmedetomidine Protects Against Oxygen-Glucose Deprivation-Induced Injury Through Inducing Astrocytes Autophagy via TSC2/mTOR Pathway. Neuromolecular Med 2019; 22:210-217. [PMID: 31654225 PMCID: PMC7230061 DOI: 10.1007/s12017-019-08576-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 10/11/2019] [Indexed: 12/13/2022]
Abstract
Although there is an increment in stroke burden in the world, stroke therapeutic strategies are still extremely limited to a minority of patients. We previously demonstrated that dexmedetomidine (DEX) protects against focal cerebral ischemia via inhibiting neurons autophagy. Nevertheless, the role of DEX in regulating astrocytes autophagic status in oxygen–glucose deprivation, a condition that mimics cerebral ischemia, is still unknown. In this study, we have shown that DEX and DEX + RAPA (autophagy inducer) increased viability and reduced apoptosis of primary astrocytes in oxygen–glucose deprivation (OGD) model compared with DEX + 3-methyladenine (3-MA) (autophagy inhibitor). DEX induced the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin 1, while reduced the expression of p62 in primary cultured astrocytes through induction of autophagy. In addition, DEX enhanced the expression of tuberous sclerosis complex 2 (TSC2) in primary cultured astrocytes, while reduced the expression of mammalian target of rapamycin (mTOR). In conclusion, our study suggests that DEX exerts a neuroprotection against OGD-induced astrocytes injury via activation of astrocytes autophagy by regulating the TSC2/mTOR signaling pathway, which provides a new insight into the mechanisms of DEX treatment for acute ischemic injury.
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Yuan X, Bhat OM, Lohner H, Li N, Zhang Y, Li PL. Inhibitory effects of growth differentiation factor 11 on autophagy deficiency-induced dedifferentiation of arterial smooth muscle cells. Am J Physiol Heart Circ Physiol 2019; 316:H345-H356. [PMID: 30462553 PMCID: PMC6397385 DOI: 10.1152/ajpheart.00342.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 10/24/2018] [Accepted: 11/15/2018] [Indexed: 12/27/2022]
Abstract
Growth differentiation factor (GDF)11 has been reported to reverse age-related cardiac hypertrophy in mice and cause youthful regeneration of cardiomyocytes. The present study attempted to test a hypothesis that GDF11 counteracts the pathologic dedifferentiation of mouse carotid arterial smooth muscle cells (CASMCs) due to deficient autophagy. By real-time RT-PCR and Western blot analysis, exogenously administrated GDF11 was found to promote CASMC differentiation with increased expression of various differentiation markers (α-smooth muscle actin, myogenin, myogenic differentiation, and myosin heavy chain) as well as decreased expression of dedifferentiation markers (vimentin and proliferating cell nuclear antigen). Upregulation of the GDF11 gene by trichostatin A (TSA) or CRISPR-cas9 activating plasmids also stimulated the differentiation of CASMCs. Either GDF11 or TSA treatment blocked 7-ketocholesterol-induced CASMC dedifferentiation and autophagosome accumulation as well as lysosome inhibitor bafilomycin-induced dedifferentiation and autophagosome accumulation. Moreover, in CASMCs from mice lacking the CD38 gene, an autophagy deficiency model in CASMCs, GDF11 also inhibited its phenotypic transition to dedifferentiation status. Correspondingly, TSA treatment was shown to decrease GDF11 expression and reverse CASMC dedifferentiation in the partial ligated carotid artery of mice. The inhibitory effects of TSA on dedifferentiation of CASMCs were accompanied by reduced autophagosome accumulation in the arterial wall, which was accompanied by attenuated neointima formation in partial ligated carotid arteries. We concluded that GDF11 promotes CASMC differentiation and prevents the phenotypic transition of these cells induced by autophagosome accumulation during different pathological stimulations, such as Western diet, lysosome function deficiency, and inflammation. NEW & NOTEWORTHY The present study demonstrates that growth differentiation factor (GDF)11 promotes autophagy and subsequent differentiation in carotid arterial smooth muscle cells. Upregulation of GDF11 counteracts dedifferentiation under different pathological conditions. These findings provide novel insights into the regulatory role of GDF11 in the counteracting of sclerotic arterial diseases and also suggest that activation or induction of GDF11 may be a new therapeutic strategy for the treatment or prevention of these diseases.
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Affiliation(s)
- Xinxu Yuan
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Owais M Bhat
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Hannah Lohner
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Ningjun Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Yang Zhang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston , Houston, Texas
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
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