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Patel MA, Daley M, Van Nynatten LR, Slessarev M, Cepinskas G, Fraser DD. A reduced proteomic signature in critically ill Covid-19 patients determined with plasma antibody micro-array and machine learning. Clin Proteomics 2024; 21:33. [PMID: 38760690 PMCID: PMC11100131 DOI: 10.1186/s12014-024-09488-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 05/06/2024] [Indexed: 05/19/2024] Open
Abstract
BACKGROUND COVID-19 is a complex, multi-system disease with varying severity and symptoms. Identifying changes in critically ill COVID-19 patients' proteomes enables a better understanding of markers associated with susceptibility, symptoms, and treatment. We performed plasma antibody microarray and machine learning analyses to identify novel proteins of COVID-19. METHODS A case-control study comparing the concentration of 2000 plasma proteins in age- and sex-matched COVID-19 inpatients, non-COVID-19 sepsis controls, and healthy control subjects. Machine learning was used to identify a unique proteome signature in COVID-19 patients. Protein expression was correlated with clinically relevant variables and analyzed for temporal changes over hospitalization days 1, 3, 7, and 10. Expert-curated protein expression information was analyzed with Natural language processing (NLP) to determine organ- and cell-specific expression. RESULTS Machine learning identified a 28-protein model that accurately differentiated COVID-19 patients from ICU non-COVID-19 patients (accuracy = 0.89, AUC = 1.00, F1 = 0.89) and healthy controls (accuracy = 0.89, AUC = 1.00, F1 = 0.88). An optimal nine-protein model (PF4V1, NUCB1, CrkL, SerpinD1, Fen1, GATA-4, ProSAAS, PARK7, and NET1) maintained high classification ability. Specific proteins correlated with hemoglobin, coagulation factors, hypertension, and high-flow nasal cannula intervention (P < 0.01). Time-course analysis of the 28 leading proteins demonstrated no significant temporal changes within the COVID-19 cohort. NLP analysis identified multi-system expression of the key proteins, with the digestive and nervous systems being the leading systems. CONCLUSIONS The plasma proteome of critically ill COVID-19 patients was distinguishable from that of non-COVID-19 sepsis controls and healthy control subjects. The leading 28 proteins and their subset of 9 proteins yielded accurate classification models and are expressed in multiple organ systems. The identified COVID-19 proteomic signature helps elucidate COVID-19 pathophysiology and may guide future COVID-19 treatment development.
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Affiliation(s)
- Maitray A Patel
- Epidemiology and Biostatistics, Western University, London, ON, N6A 3K7, Canada
| | - Mark Daley
- Epidemiology and Biostatistics, Western University, London, ON, N6A 3K7, Canada
- Computer Science, Western University, London, ON, N6A 3K7, Canada
| | | | - Marat Slessarev
- Medicine, Western University, London, ON, N6A 3K7, Canada
- Lawson Health Research Institute, London, ON, N6C 2R5, Canada
| | - Gediminas Cepinskas
- Lawson Health Research Institute, London, ON, N6C 2R5, Canada
- Medical Biophysics, Western University, London, ON, N6A 3K7, Canada
| | - Douglas D Fraser
- Lawson Health Research Institute, London, ON, N6C 2R5, Canada.
- Children's Health Research Institute, London, ON, N6C 4V3, Canada.
- Pediatrics, Western University, London, ON, N6A 3K7, Canada.
- Clinical Neurological Sciences, Western University, London, ON, N6A 3K7, Canada.
- Physiology & Pharmacology, Western University, London, ON, N6A 3K7, Canada.
- London Health Sciences Centre, 800 Commissioners Road East, London, ON, N6A 5W9, Canada.
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Mitias S, Schaffer N, Nair S, Hook C, Lindberg I. ProSAAS is Preferentially Secreted from Neurons During Homeostatic Scaling and Reduces Amyloid Plaque Size in the 5xFAD Mouse Hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.18.590133. [PMID: 38712265 PMCID: PMC11071301 DOI: 10.1101/2024.04.18.590133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The accumulation of β-amyloid in Alzheimer's disease greatly impacts neuronal health and synaptic function. To maintain network stability in the face of altered synaptic activity, neurons engage a feedback mechanism termed homeostatic scaling; however, this process is thought to be disrupted during disease progression. Previous proteomics studies have shown that one of the most highly regulated proteins in cell culture models of homeostatic scaling is the small secretory chaperone proSAAS. Our prior work has shown that proSAAS exhibits anti-aggregant behavior against alpha synuclein and β-amyloid fibrillation in vitro, and is upregulated in cell models of proteostatic stress. However, the specific role that this protein might play in homeostatic scaling, and its anti-aggregant role in Alzheimer's progression, is not clear. To learn more about the role of proSAAS in maintaining hippocampal proteostasis, we compared its expression in a primary neuron model of homeostatic scaling to other synaptic components using Western blotting and qPCR, revealing that proSAAS protein responses to homeostatic up- and down-regulation were significantly higher than those of two other synaptic vesicle components, 7B2 and carboxypeptidase E. However, proSAAS mRNA expression was static, suggesting translational control (and/or reduced degradation). ProSAAS was readily released upon depolarization of differentiated hippocampal cultures, supporting its synaptic localization. Immunohistochemical analysis demonstrated abundant proSAAS within the mossy fiber layer of the hippocampus in both wild-type and 5xFAD mice; in the latter, proSAAS was also concentrated around amyloid plaques. Interestingly, overexpression of proSAAS in the CA1 region via stereotaxic injection of proSAAS-encoding AAV2/1 significantly decreased amyloid plaque burden in 5xFAD mice. We hypothesize that dynamic changes in proSAAS expression play a critical role in hippocampal proteostatic processes, both in the context of normal homeostatic plasticity and in the control of protein aggregation during Alzheimer's disease progression.
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Affiliation(s)
- Samira Mitias
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Nicholas Schaffer
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Saaya Nair
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Chelsea Hook
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Iris Lindberg
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
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Wang Z, Liu X, Wang W, Xu J, Sun H, Wei J, Yu Y, Zhao Y, Wang X, Liao Z, Sun W, Jia L, Zhang Y. UPLC-MS based integrated plasma proteomic and metabolomic profiling of TSC-RAML and its relationship with everolimus treatment. Front Mol Biosci 2023; 10:1000248. [PMID: 36891236 PMCID: PMC9986496 DOI: 10.3389/fmolb.2023.1000248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Aim: To profile the plasma proteomics and metabolomics of patients with renal cysts, sporadic angiomyolipoma (S-AML) and tuberous sclerosis complex related angiomyolipoma (TSC-RAML) before and after everolimus treatment, and to find potential diagnostic and prognostic biomarkers as well as reveal the underlying mechanism of TSC tumorigenesis. Materials and Methods: We retrospectively measured the plasma proteins and metabolites from November 2016 to November 2017 in a cohort of pre-treatment and post-treatment TSC-RAML patients and compared them with renal cyst and S-AML patients by ultra-performance liquid chromatography-mass spectrometer (UPLC-MS). The tumor reduction rates of TSC-RAML were assessed and correlated with the plasma protein and metabolite levels. In addition, functional analysis based on differentially expressed molecules was performed to reveal the underlying mechanisms. Results: Eighty-five patients with one hundred and ten plasma samples were enrolled in our study. Multiple proteins and metabolites, such as pre-melanosome protein (PMEL) and S-adenosylmethionine (SAM), demonstrated both diagnostic and prognostic effects. Functional analysis revealed many dysregulated pathways, including angiogenesis synthesis, smooth muscle proliferation and migration, amino acid metabolism and glycerophospholipid metabolism. Conclusion: The plasma proteomics and metabolomics pattern of TSC-RAML was clearly different from that of other renal tumors, and the differentially expressed plasma molecules could be used as prognostic and diagnostic biomarkers. The dysregulated pathways, such as angiogenesis and amino acid metabolism, may shed new light on the treatment of TSC-RAML.
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Affiliation(s)
- Zhan Wang
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xiaoyan Liu
- School of Basic Medical College, Core facility of instrument, Institution of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Wenda Wang
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jiyu Xu
- School of Basic Medical College, Core facility of instrument, Institution of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Haidan Sun
- School of Basic Medical College, Core facility of instrument, Institution of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Wei
- Clinical Research Center, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Yuncui Yu
- Clinical Research Center, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Yang Zhao
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xu Wang
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Zhangcheng Liao
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Wei Sun
- School of Basic Medical College, Core facility of instrument, Institution of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Lulu Jia
- Clinical Research Center, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Yushi Zhang
- Department of Urology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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Bae H, Gurinovich A, Karagiannis TT, Song Z, Leshchyk A, Li M, Andersen SL, Arbeev K, Yashin A, Zmuda J, An P, Feitosa M, Giuliani C, Franceschi C, Garagnani P, Mengel-From J, Atzmon G, Barzilai N, Puca A, Schork NJ, Perls TT, Sebastiani P. A Genome-Wide Association Study of 2304 Extreme Longevity Cases Identifies Novel Longevity Variants. Int J Mol Sci 2022; 24:ijms24010116. [PMID: 36613555 PMCID: PMC9820206 DOI: 10.3390/ijms24010116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/08/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
We performed a genome-wide association study (GWAS) of human extreme longevity (EL), defined as surviving past the 99th survival percentile, by aggregating data from four centenarian studies. The combined data included 2304 EL cases and 5879 controls. The analysis identified a locus in CDKN2B-AS1 (rs6475609, p = 7.13 × 10-8) that almost reached genome-wide significance and four additional loci that were suggestively significant. Among these, a novel rare variant (rs145265196) on chromosome 11 had much higher longevity allele frequencies in cases of Ashkenazi Jewish and Southern Italian ancestry compared to cases of other European ancestries. We also correlated EL-associated SNPs with serum proteins to link our findings to potential biological mechanisms that may be related to EL and are under genetic regulation. The findings from the proteomic analyses suggested that longevity-promoting alleles of significant genetic variants either provided EL cases with more youthful molecular profiles compared to controls or provided some form of protection from other illnesses, such as Alzheimer's disease, and disease progressions.
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Affiliation(s)
- Harold Bae
- Biostatistics Program, College of Public Health and Human Sciences, Oregon State University, Corvallis, OR 97331, USA
- Correspondence:
| | - Anastasia Gurinovich
- Center for Quantitative Methods and Data Science, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA
| | - Tanya T. Karagiannis
- Center for Quantitative Methods and Data Science, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA
| | - Zeyuan Song
- Department of Biostatistics, Boston University School of Public Health, Boston, MA 02118, USA
| | - Anastasia Leshchyk
- Division of Computational Biomedicine, Boston University, Boston, MA 02215, USA
| | - Mengze Li
- Division of Computational Biomedicine, Boston University, Boston, MA 02215, USA
| | - Stacy L. Andersen
- Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02215, USA
| | - Konstantin Arbeev
- Social Science Research Institute, Duke University, Durham, NC 27708, USA
| | - Anatoliy Yashin
- Social Science Research Institute, Duke University, Durham, NC 27708, USA
| | - Joseph Zmuda
- School of Public Health, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ping An
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Mary Feitosa
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Cristina Giuliani
- Department of Biological, Geological and Environmental Sciences, University of Bologna, 40126 Bologna, Italy
| | - Claudio Franceschi
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, 40126 Bologna, Italy
- Department of Applied Mathematics and Laboratory of Systems Medicine of Aging, Lobachevsky University, 603950 Nizhny Novgorod, Russia
| | - Paolo Garagnani
- Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, 40126 Bologna, Italy
| | - Jonas Mengel-From
- Department of Public Health, University of Southern Denmark, 5230 Odense, Denmark
| | - Gil Atzmon
- Faculty of Natural Sciences, University of Haifa, Haifa 3498838, Israel
- Department of Genetics and Medicine, Albert Einstein College of Medicine, Bronx, NY 10451, USA
| | - Nir Barzilai
- Department of Genetics and Medicine, Albert Einstein College of Medicine, Bronx, NY 10451, USA
| | - Annibale Puca
- Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, 84084 Fisciano, Italy
- Cardiovascular Research Unit, IRCCS MultiMedica, 20099 Milan, Italy
| | - Nicholas J. Schork
- Quantitative Medicine & Systems Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, USA
| | - Thomas T. Perls
- Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02215, USA
| | - Paola Sebastiani
- Center for Quantitative Methods and Data Science, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA 02111, USA
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Rico-Llanos G, Porras-Perales Ó, Escalante S, Vázquez-Calero DB, Valiente L, Castillo MI, Pérez-Tejeiro JM, Baglietto-Vargas D, Becerra J, Reguera JM, Duran I, Csukasi F. Cellular stress modulates severity of the inflammatory response in lungs via cell surface BiP. Front Immunol 2022; 13:1054962. [DOI: 10.3389/fimmu.2022.1054962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/27/2022] [Indexed: 11/21/2022] Open
Abstract
Inflammation is a central pathogenic feature of the acute respiratory distress syndrome (ARDS) in COVID-19. Previous pathologies such as diabetes, autoimmune or cardiovascular diseases become risk factors for the severe hyperinflammatory syndrome. A common feature among these risk factors is the subclinical presence of cellular stress, a finding that has gained attention after the discovery that BiP (GRP78), a master regulator of stress, participates in the SARS-CoV-2 recognition. Here, we show that BiP serum levels are higher in COVID-19 patients who present certain risk factors. Moreover, early during the infection, BiP levels predict severe pneumonia, supporting the use of BiP as a prognosis biomarker. Using a mouse model of pulmonary inflammation, we observed increased levels of cell surface BiP (cs-BiP) in leukocytes during inflammation. This corresponds with a higher number of neutrophiles, which show naturally high levels of cs-BiP, whereas alveolar macrophages show a higher than usual exposure of BiP in their cell surface. The modulation of cellular stress with the use of a clinically approved drug, 4-PBA, resulted in the amelioration of the lung hyperinflammatory response, supporting the anti-stress therapy as a valid therapeutic strategy for patients developing ARDS. Finally, we identified stress-modulated proteins that shed light into the mechanism underlying the cellular stress-inflammation network in lungs.
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Mesgarzadeh JS, Buxbaum JN, Wiseman RL. Stress-responsive regulation of extracellular proteostasis. J Cell Biol 2022; 221:213026. [PMID: 35191945 PMCID: PMC8868021 DOI: 10.1083/jcb.202112104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/02/2022] [Accepted: 02/02/2022] [Indexed: 12/18/2022] Open
Abstract
Genetic, environmental, and aging-related insults can promote the misfolding and subsequent aggregation of secreted proteins implicated in the pathogenesis of numerous diseases. This has led to considerable interest in understanding the molecular mechanisms responsible for regulating proteostasis in extracellular environments such as the blood and cerebrospinal fluid (CSF). Extracellular proteostasis is largely dictated by biological pathways comprising chaperones, folding enzymes, and degradation factors localized to the ER and extracellular space. These pathways limit the accumulation of nonnative, potentially aggregation-prone proteins in extracellular environments. Many reviews discuss the molecular mechanisms by which these pathways impact the conformational integrity of the secreted proteome. Here, we instead focus on describing the stress-responsive mechanisms responsible for adapting ER and extracellular proteostasis pathways to protect the secreted proteome from pathologic insults that challenge these environments. Further, we highlight new strategies to identify stress-responsive pathways involved in regulating extracellular proteostasis and describe the pathologic and therapeutic implications for these pathways in human disease.
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Affiliation(s)
| | - Joel N Buxbaum
- Department of Molecular Medicine, Scripps Research, La Jolla, CA
| | - R Luke Wiseman
- Department of Molecular Medicine, Scripps Research, La Jolla, CA
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7
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Lindberg I, Shu Z, Lam H, Helwig M, Yucer N, Laperle A, Svendsen C, Di Monte DA, Maidment NT. The proSAAS Chaperone Provides Neuroprotection and Attenuates Transsynaptic α-Synuclein Spread in Rodent Models of Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2022; 12:1463-1478. [PMID: 35527562 PMCID: PMC9731515 DOI: 10.3233/jpd-213053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Parkinson's disease involves aberrant aggregation of the synaptic protein alpha-synuclein (aSyn) in the nigrostriatal tract. We have previously shown that proSAAS, a small neuronal chaperone, blocks aSyn-induced dopaminergic cytotoxicity in primary nigral cultures. OBJECTIVE To determine if proSAAS overexpression is neuroprotective in animal models of Parkinson's disease. METHODS proSAAS- or GFP-encoding lentivirus was injected together with human aSyn-expressing AAV unilaterally into the substantia nigra of rats and motor asymmetry assessed using a battery of motor performance tests. Dopamine neuron survival was assessed by nigral stereology and striatal tyrosine hydroxylase (TH) densitometry. To examine transsynaptic spread of aSyn, aSyn AAV was injected into the vagus of mice in the presence of AAVs encoding either GFP or proSAAS; the spread of aSyn-positive neurites into rostral nuclei was quantified following immunohistochemistry. RESULTS Coinjection of proSAAS-encoding lentivirus profoundly reduced the motor asymmetry caused by unilateral nigral AAV-mediated human aSyn overexpression. This was accompanied by significant amelioration of the human aSyn-induced loss of both nigral TH-positive cells and striatal TH-positive terminals, demonstrating clear proSAAS-mediated protection of the nigrostriatal tract. ProSAAS overexpression reduced human aSyn protein levels in nigra and striatum and reduced the loss of TH protein in both regions. Following vagal administration of human aSyn-encoding AAV, the number of human aSyn-positive neurites in the pons and caudal midbrain was considerably reduced in mice coinjected with proSAAS-, but not GFP-encoding AAV, supporting proSAAS-mediated blockade of transsynaptic aSyn transmission. CONCLUSION The proSAAS chaperone may represent a promising target for therapeutic development in Parkinson's disease.
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Affiliation(s)
- Iris Lindberg
- University of Maryland-Baltimore;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
| | - Zhan Shu
- University of California-Los Angeles
| | - Hoa Lam
- University of California-Los Angeles
| | | | - Nur Yucer
- Cedars-Sinai Medical Center, Los Angeles
| | | | | | | | - Nigel T. Maidment
- University of California-Los Angeles;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
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8
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Identifying new molecular players in extracellular proteostasis. Biochem Soc Trans 2021; 50:321-334. [PMID: 34940856 DOI: 10.1042/bst20210369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 02/02/2023]
Abstract
Proteostasis refers to a delicately tuned balance between the processes of protein synthesis, folding, localization, and the degradation of proteins found inside and outside cells. Our understanding of extracellular proteostasis is rather limited and largely restricted to knowledge of 11 currently established extracellular chaperones (ECs). This review will briefly outline what is known of the established ECs, before moving on to discuss experimental strategies used to identify new members of this growing family, and an examination of a group of putative new ECs identified using one of these approaches. An observation that emerges from an analysis of the expanding number of ECs is that all of these proteins are multifunctional. Strikingly, the armory of activities each possess uniquely suit them as a group to act together at sites of tissue damage, infection, and inflammation to restore homeostasis. Lastly, we highlight outstanding questions to guide future research in this field.
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9
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Chaplot K, Jarvela TS, Lindberg I. Secreted Chaperones in Neurodegeneration. Front Aging Neurosci 2020; 12:268. [PMID: 33192447 PMCID: PMC7481362 DOI: 10.3389/fnagi.2020.00268] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, is a combination of cellular processes that govern protein quality control, namely, protein translation, folding, processing, and degradation. Disruptions in these processes can lead to protein misfolding and aggregation. Proteostatic disruption can lead to cellular changes such as endoplasmic reticulum or oxidative stress; organelle dysfunction; and, if continued, to cell death. A majority of neurodegenerative diseases involve the pathologic aggregation of proteins that subverts normal neuronal function. While prior reviews of neuronal proteostasis in neurodegenerative processes have focused on cytoplasmic chaperones, there is increasing evidence that chaperones secreted both by neurons and other brain cells in the extracellular – including transsynaptic – space play important roles in neuronal proteostasis. In this review, we will introduce various secreted chaperones involved in neurodegeneration. We begin with clusterin and discuss its identification in various protein aggregates, and the use of increased cerebrospinal fluid (CSF) clusterin as a potential biomarker and as a potential therapeutic. Our next secreted chaperone is progranulin; polymorphisms in this gene represent a known genetic risk factor for frontotemporal lobar degeneration, and progranulin overexpression has been found to be effective in reducing Alzheimer’s- and Parkinson’s-like neurodegenerative phenotypes in mouse models. We move on to BRICHOS domain-containing proteins, a family of proteins containing highly potent anti-amyloidogenic activity; we summarize studies describing the biochemical mechanisms by which recombinant BRICHOS protein might serve as a therapeutic agent. The next section of the review is devoted to the secreted chaperones 7B2 and proSAAS, small neuronal proteins which are packaged together with neuropeptides and released during synaptic activity. Since proteins can be secreted by both classical secretory and non-classical mechanisms, we also review the small heat shock proteins (sHsps) that can be secreted from the cytoplasm to the extracellular environment and provide evidence for their involvement in extracellular proteostasis and neuroprotection. Our goal in this review focusing on extracellular chaperones in neurodegenerative disease is to summarize the most recent literature relating to neurodegeneration for each secreted chaperone; to identify any common mechanisms; and to point out areas of similarity as well as differences between the secreted chaperones identified to date.
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Affiliation(s)
- Kriti Chaplot
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
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