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Cong L, He Y, Wu Y, Li Z, Ding S, Liang W, Xiao X, Zhang H, Wang L. Discovery and validation of molecular patterns and immune characteristics in the peripheral blood of ischemic stroke patients. PeerJ 2024; 12:e17208. [PMID: 38650649 PMCID: PMC11034498 DOI: 10.7717/peerj.17208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Background Stroke is a disease with high morbidity, disability, and mortality. Immune factors play a crucial role in the occurrence of ischemic stroke (IS), but their exact mechanism is not clear. This study aims to identify possible immunological mechanisms by recognizing immune-related biomarkers and evaluating the infiltration pattern of immune cells. Methods We downloaded datasets of IS patients from GEO, applied R language to discover differentially expressed genes, and elucidated their biological functions using GO, KEGG analysis, and GSEA analysis. The hub genes were then obtained using two machine learning algorithms (least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE)) and the immune cell infiltration pattern was revealed by CIBERSORT. Gene-drug target networks and mRNA-miRNA-lncRNA regulatory networks were constructed using Cytoscape. Finally, we used RT-qPCR to validate the hub genes and applied logistic regression methods to build diagnostic models validated with ROC curves. Results We screened 188 differentially expressed genes whose functional analysis was enriched to multiple immune-related pathways. Six hub genes (ANTXR2, BAZ2B, C5AR1, PDK4, PPIH, and STK3) were identified using LASSO and SVM-RFE. ANTXR2, BAZ2B, C5AR1, PDK4, and STK3 were positively correlated with neutrophils and gamma delta T cells, and negatively correlated with T follicular helper cells and CD8, while PPIH showed the exact opposite trend. Immune infiltration indicated increased activity of monocytes, macrophages M0, neutrophils, and mast cells, and decreased infiltration of T follicular helper cells and CD8 in the IS group. The ceRNA network consisted of 306 miRNA-mRNA interacting pairs and 285 miRNA-lncRNA interacting pairs. RT-qPCR results indicated that the expression levels of BAZ2B, C5AR1, PDK4, and STK3 were significantly increased in patients with IS. Finally, we developed a diagnostic model based on these four genes. The AUC value of the model was verified to be 0.999 in the training set and 0.940 in the validation set. Conclusion Our research explored the immune-related gene expression modules and provided a specific basis for further study of immunomodulatory therapy of IS.
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Affiliation(s)
- Lin Cong
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Yijie He
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Yun Wu
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Ze Li
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Siwen Ding
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Weiwei Liang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Xingjun Xiao
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Huixue Zhang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
| | - Lihua Wang
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
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Zheng H, Wang H, Xu Y, Xu X, Zhu Z, Fang J, Song Z, Liu J. MST2 Acts via AKT Activity to Promote Neurite Outgrowth and Functional Recovery after Spinal Cord Injury in Mice. Mol Neurobiol 2024:10.1007/s12035-024-04158-9. [PMID: 38581538 DOI: 10.1007/s12035-024-04158-9] [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: 08/17/2023] [Accepted: 03/28/2024] [Indexed: 04/08/2024]
Abstract
Spinal cord injury (SCI) constitutes a significant clinical challenge, and there is extensive research focused on identifying molecular activities that can facilitate the repair of spinal cord injuries. Mammalian sterile 20-like kinase 2 (MST2), a core component of the Hippo signaling pathway, plays a key role in apoptosis and cell growth. However, its role in neurite outgrowth after spinal cord injury remains unknown. Through comprehensive in vitro and in vivo experiments, we demonstrated that MST2, predominantly expressed in neurons, actively participated in the natural development of the CNS. Post-SCI, MST2 expression significantly increased, indicating its activation and potential role in the early stages of neural recovery. Detailed analyses showed that MST2 knockdown impaired neurite outgrowth and motor function recovery, whereas MST2 overexpression led to the opposite effects, underscoring MST2's neuroprotective role in enhancing neural repair. Further, we elucidated the mechanism underlying MST2's action, revealing its interaction with AKT and positive regulation of AKT activity, a well-established promoter of neurite outgrowth. Notably, MST2's promotion of neurite outgrowth and motor functional recovery was diminished by AKT inhibitors, highlighting the dependency of MST2's neuroprotective effects on AKT signaling. In conclusion, our findings affirmed MST2's pivotal role in fostering neuronal neurite outgrowth and facilitating functional recovery after SCI, mediated through its positive modulation of AKT activity. In conclusion, our findings confirmed MST2's crucial role in neural protection, promoting neurite outgrowth and functional recovery after SCI through positive AKT activity modulation. These results position MST2 as a potential therapeutic target for SCI, offering new insights into strategies for enhancing neuroregeneration and functional restoration.
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Affiliation(s)
- Hongming Zheng
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China
- Department of Orthopedics, The People's Hospital of Danyang, Danyang, 212300, China
| | - Honghai Wang
- Department of Orthopedics, The NO. 2 People's Hospital of Fuyang, Fuyang, China
| | - Yi Xu
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Xu Xu
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Zhenghuan Zhu
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Jiawei Fang
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Zhiwen Song
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China.
| | - Jinbo Liu
- Department of Spinal Surgery, The Third Affiliated Hospital of Soochow University, Changzhou, China.
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Podvin S, Rosenthal SB, Poon W, Wei E, Fisch KM, Hook V. Mutant Huntingtin Protein Interaction Map Implicates Dysregulation of Multiple Cellular Pathways in Neurodegeneration of Huntington's Disease. J Huntingtons Dis 2022; 11:243-267. [PMID: 35871359 PMCID: PMC9484122 DOI: 10.3233/jhd-220538] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a genetic neurodegenerative disease caused by trinucleotide repeat (CAG) expansions in the human HTT gene encoding the huntingtin protein (Htt) with an expanded polyglutamine tract. OBJECTIVE HD models from yeast to transgenic mice have investigated proteins interacting with mutant Htt that may initiate molecular pathways of cell death. There is a paucity of datasets of published Htt protein interactions that include the criteria of 1) defining fragments or full-length Htt forms, 2) indicating the number of poly-glutamines of the mutant and wild-type Htt forms, and 3) evaluating native Htt interaction complexes. This research evaluated such interactor data to gain understanding of Htt dysregulation of cellular pathways. METHODS Htt interacting proteins were compiled from the literature that meet our criteria and were subjected to network analysis via clustering, gene ontology, and KEGG pathways using rigorous statistical methods. RESULTS The compiled data of Htt interactors found that both mutant and wild-type Htt interact with more than 2,971 proteins. Application of a community detection algorithm to all known Htt interactors identified significant signal transduction, membrane trafficking, chromatin, and mitochondrial clusters, among others. Binomial analyses of a subset of reported protein interactor information determined that chromatin organization, signal transduction and endocytosis were diminished, while mitochondria, translation and membrane trafficking had enriched overall edge effects. CONCLUSION The data support the hypothesis that mutant Htt disrupts multiple cellular processes causing toxicity. This dataset is an open resource to aid researchers in formulating hypotheses of HD mechanisms of pathogenesis.
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Affiliation(s)
- Sonia Podvin
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Sara Brin Rosenthal
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA
| | - William Poon
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Enlin Wei
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics, University of California, San Diego, La Jolla, CA, USA.,Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Vivian Hook
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA.,Department of Neuroscience and Dept of Pharmacology, School of Medicine, University of California, San Diego, La Jolla, CA, USA
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Huang S, Mei H, Lu L, Kuang Z, Heng Y, Xu L, Liang X, Qiu M, Pan X. Conformational transitions of caspase-6 in substrate-induced activation process explored by perturbation-response scanning combined with targeted molecular dynamics. Comput Struct Biotechnol J 2021; 19:4156-4164. [PMID: 34527189 PMCID: PMC8342898 DOI: 10.1016/j.csbj.2021.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/17/2021] [Accepted: 07/23/2021] [Indexed: 11/23/2022] Open
Abstract
Caspase-6 participates in a series of neurodegenerative pathways, and has aroused widespread attentions as a promising molecular target for the treatment of neurodegeneration. Caspase-6 is a homodimer with 6 central-stranded β-sheets and 5 α-helices in each monomer. Previous crystallographic studies suggested that the 60′s, 90′s and 130′s helices of caspase-6 undergo a distinctive conformational transition upon substrate binding. Although the caspase-6 structures in apo and active states have been determined, the conformational transition process between the two states remains poorly understood. In this work, perturbation-response scanning (PRS) combined with targeted molecular dynamics (TMD) simulations was employed to unravel the atomistic mechanism of the dynamic conformational transitions underlying the substrate-induced activation process of caspase-6. The results showed that the conformational transition of caspase-6 from apo to active states is mainly characterized by structural rearrangements of the substrate-binding site as well as the conformational changes of 60′s and 130′s extended helices. The H-bond interactions between L1, 130′s helix and 90′s helix are proved to be key determinant factors for substrate-induced conformational transition. These findings provide valuable insights into the activation mechanism of caspase-6 as well as the molecular design of caspase-6 inhibitors.
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Affiliation(s)
- Shuheng Huang
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Hu Mei
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Laichun Lu
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Zuyin Kuang
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Yu Heng
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Lei Xu
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Xiaoqi Liang
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Minyao Qiu
- Key Laboratory of Biorheological Science and Technology (Ministry of Education), College of Bioengineering, Chongqing University, Chongqing 400045, China
| | - Xianchao Pan
- Department of Medicinal Chemistry, College of Pharmacy, Southwest Medical University, Luzhou, Sichuan 646000, China
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Impaired inhibitory GABAergic synaptic transmission and transcription studied in single neurons by Patch-seq in Huntington's disease. Proc Natl Acad Sci U S A 2021; 118:2020293118. [PMID: 33952696 DOI: 10.1073/pnas.2020293118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Transcriptional dysregulation in Huntington's disease (HD) causes functional deficits in striatal neurons. Here, we performed Patch-sequencing (Patch-seq) in an in vitro HD model to investigate the effects of mutant Huntingtin (Htt) on synaptic transmission and gene transcription in single striatal neurons. We found that expression of mutant Htt decreased the synaptic output of striatal neurons in a cell autonomous fashion and identified a number of genes whose dysregulation was correlated with physiological deficiencies in mutant Htt neurons. In support of a pivotal role for epigenetic mechanisms in HD pathophysiology, we found that inhibiting histone deacetylase 1/3 activities rectified several functional and morphological deficits and alleviated the aberrant transcriptional profiles in mutant Htt neurons. With this study, we demonstrate that Patch-seq technology can be applied both to better understand molecular mechanisms underlying a complex neurological disease at the single-cell level and to provide a platform for screening for therapeutics for the disease.
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Qi Y, Sun D, Yang W, Xu B, Lv D, Han Y, Sun M, Jiang S, Hu W, Yang Y. Mammalian Sterile 20-Like Kinase (MST) 1/2: Crucial Players in Nervous and Immune System and Neurological Disorders. J Mol Biol 2020; 432:3177-3190. [PMID: 32198112 DOI: 10.1016/j.jmb.2020.03.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 02/25/2020] [Accepted: 03/09/2020] [Indexed: 12/28/2022]
Abstract
As central components of the Hippo signaling pathway in mammals, the mammalian sterile 20-like kinase 1 (MST1) and MST2 protein kinases regulate cell proliferation, survival, and death and are involved in the homeostasis of many tissues. Recent studies have elucidated the roles of MST1 and MST2 in the nervous system and immune system, particularly in neurological disorders, which are influenced by aging. In this review, we provide a comprehensive overview of these research areas. First, the activation mechanisms and roles of MST1 and MST2 in neurons, non-neuronal cells, and immune cells are introduced. The roles of MST1 and MST2 in neurological disorders, including brain tumors, cerebrovascular diseases, neurodegenerative disorders, and neuromuscular disorders, are then presented. Finally, the existing obstacles for further research are discussed. Collectively, the information compiled herein provides a common framework for the function of MST1 and MST2 in the nervous system, should contribute to the design of further experiments, and sheds light on potential treatments for aging associated neurological disorders.
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Affiliation(s)
- Yating Qi
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China
| | - Dongdong Sun
- Department of Cardiology, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an 710032, China
| | - Wenwen Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China
| | - Baoping Xu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China
| | - Dewen Lv
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China
| | - Yuehu Han
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an 710032, China
| | - Meng Sun
- Department of Cardiology, The First Hospital of Shanxi Medical University, 85 Jiefang South Road, Taiyuan 030001, China
| | - Shuai Jiang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China
| | - Wei Hu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China.
| | - Yang Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, 229 Taibai North Road, Xi'an 710069, China.
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Soares TR, Reis SD, Pinho BR, Duchen MR, Oliveira JMA. Targeting the proteostasis network in Huntington's disease. Ageing Res Rev 2019; 49:92-103. [PMID: 30502498 PMCID: PMC6320389 DOI: 10.1016/j.arr.2018.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion mutation in the huntingtin protein. Expansions above 40 polyglutamine repeats are invariably fatal, following a symptomatic period characterised by choreiform movements, behavioural abnormalities, and cognitive decline. While mutant huntingtin (mHtt) is widely expressed from early life, most patients with HD present in mid-adulthood, highlighting the role of ageing in disease pathogenesis. mHtt undergoes proteolytic cleavage, misfolding, accumulation, and aggregation into inclusion bodies. The emerging model of HD pathogenesis proposes that the chronic production of misfolded mHtt overwhelms the chaperone machinery, diverting other misfolded clients to the proteasome and the autophagy pathways, ultimately leading to a global collapse of the proteostasis network. Multiple converging hypotheses also implicate ageing and its impact in the dysfunction of organelles as additional contributing factors to the collapse of proteostasis in HD. In particular, mitochondrial function is required to sustain the activity of ATP-dependent chaperones and proteolytic machinery. Recent studies elucidating mitochondria-endoplasmic reticulum interactions and uncovering a dedicated proteostasis machinery in mitochondria, suggest that mitochondria play a more active role in the maintenance of cellular proteostasis than previously thought. The enhancement of cytosolic proteostasis pathways shows promise for HD treatment, protecting cells from the detrimental effects of mHtt accumulation. In this review, we consider how mHtt and its post translational modifications interfere with protein quality control pathways, and how the pharmacological and genetic modulation of components of the proteostasis network impact disease phenotypes in cellular and in vivo HD models.
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Affiliation(s)
- Tânia R Soares
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Sara D Reis
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK.
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8
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Posey AE, Ruff KM, Harmon TS, Crick SL, Li A, Diamond MI, Pappu RV. Profilin reduces aggregation and phase separation of huntingtin N-terminal fragments by preferentially binding to soluble monomers and oligomers. J Biol Chem 2018; 293:3734-3746. [PMID: 29358329 PMCID: PMC5846159 DOI: 10.1074/jbc.ra117.000357] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/16/2018] [Indexed: 11/06/2022] Open
Abstract
Huntingtin N-terminal fragments (Htt-NTFs) with expanded polyglutamine tracts form a range of neurotoxic aggregates that are associated with Huntington's disease. Here, we show that aggregation of Htt-NTFs, irrespective of polyglutamine length, yields at least three phases (designated M, S, and F) that are delineated by sharp concentration thresholds and distinct aggregate sizes and morphologies. We found that monomers and oligomers make up the soluble M phase, ∼25-nm spheres dominate in the soluble S phase, and long, linear fibrils make up the insoluble F phase. Previous studies showed that profilin, an abundant cellular protein, reduces Htt-NTF aggregation and toxicity in cells. We confirm that profilin achieves its cellular effects through direct binding to the C-terminal proline-rich region of Htt-NTFs. We show that profilin preferentially binds to Htt-NTF M-phase species and destabilizes aggregation and phase separation by shifting the concentration boundaries for phase separation to higher values through a process known as polyphasic linkage. Our experiments, aided by coarse-grained computer simulations and theoretical analysis, suggest that preferential binding of profilin to the M-phase species of Htt-NTFs is enhanced through a combination of specific interactions between profilin and polyproline segments and auxiliary interactions between profilin and polyglutamine tracts. Polyphasic linkage may be a general strategy that cells utilize to regulate phase behavior of aggregation-prone proteins. Accordingly, detailed knowledge of phase behavior and an understanding of how ligands modulate phase boundaries may pave the way for developing new therapeutics against a variety of aggregation-prone proteins.
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Affiliation(s)
- Ammon E Posey
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Kiersten M Ruff
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Tyler S Harmon
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Scott L Crick
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130
| | - Aimin Li
- the Department of Neurology, Washington University School of Medicine, St. Louis, Missouri 63108
| | - Marc I Diamond
- the Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Rohit V Pappu
- From the Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University, St. Louis, Missouri 63130,
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9
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Felgueiras J, Silva JV, Fardilha M. Adding biological meaning to human protein-protein interactions identified by yeast two-hybrid screenings: A guide through bioinformatics tools. J Proteomics 2018; 171:127-140. [DOI: 10.1016/j.jprot.2017.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/26/2017] [Accepted: 05/13/2017] [Indexed: 02/02/2023]
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10
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Girling KD, Demers MJ, Laine J, Zhang S, Wang YT, Graham RK. Activation of caspase-6 and cleavage of caspase-6 substrates is an early event in NMDA receptor-mediated excitotoxicity. J Neurosci Res 2017; 96:391-406. [DOI: 10.1002/jnr.24153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/10/2017] [Accepted: 08/18/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Kimberly D. Girling
- University of British Columbia, Brain Research Centre & Department of Medicine; Vancouver British Columbia Canada
| | - Marie-Josee Demers
- Research Centre on Aging, Department Pharmacology and Physiology, Faculty of Medicine and Health Sciences; University of Sherbrooke; Sherbrooke Quebec Canada
| | - Jean Laine
- Research Centre on Aging, Department Pharmacology and Physiology, Faculty of Medicine and Health Sciences; University of Sherbrooke; Sherbrooke Quebec Canada
| | - Shu Zhang
- University of British Columbia, Brain Research Centre & Department of Medicine; Vancouver British Columbia Canada
| | - Yu Tian Wang
- University of British Columbia, Brain Research Centre & Department of Medicine; Vancouver British Columbia Canada
| | - Rona K. Graham
- Research Centre on Aging, Department Pharmacology and Physiology, Faculty of Medicine and Health Sciences; University of Sherbrooke; Sherbrooke Quebec Canada
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11
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Multiple proteolytic events in caspase-6 self-activation impact conformations of discrete structural regions. Proc Natl Acad Sci U S A 2017; 114:E7977-E7986. [PMID: 28864531 DOI: 10.1073/pnas.1704640114] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Caspase-6 is critical to the neurodegenerative pathways of Alzheimer's, Huntington's, and Parkinson's diseases and has been identified as a potential molecular target for treatment of neurodegeneration. Thus, understanding the global and regional changes in dynamics and conformation provides insights into the unique properties of caspase-6 that may contribute to achieving control of its function. In this work, hydrogen/deuterium exchange MS (H/DX-MS) was used to map the local changes in the conformational flexibility of procaspase-6 at the discrete states that reflect the series of cleavage events that ultimately lead to the fully active, substrate-bound state. Intramolecular self-cleavage at Asp-193 evoked higher solvent exposure in the regions of the substrate-binding loops L1, L3, and L4 and in the 130s region, the intersubunit linker region, the 26-32 region as well as in the stabilized loop 2. Additional removal of the linker allowed caspase-6 to gain more flexibility in the 130s region and in the L2 region converting caspase-6 to a competent substrate-binding state. The prodomain region was found to be intrinsically disordered independent of the activation state of caspase-6; however, its complete removal resulted in the protection of the adjacent 26-32 region, suggesting that this region may play a regulatory role. The molecular details of caspase-6 dynamics in solution provide a comprehensive scaffold for strategic design of therapeutic approaches for neurodegenerative disorders.
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12
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Dagbay KB, Bolik-Coulon N, Savinov SN, Hardy JA. Caspase-6 Undergoes a Distinct Helix-Strand Interconversion upon Substrate Binding. J Biol Chem 2017; 292:4885-4897. [PMID: 28154009 DOI: 10.1074/jbc.m116.773499] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/01/2017] [Indexed: 12/22/2022] Open
Abstract
Caspases are cysteine aspartate proteases that are major players in key cellular processes, including apoptosis and inflammation. Specifically, caspase-6 has also been implicated in playing a unique and critical role in neurodegeneration; however, structural similarities between caspase-6 and other caspase active sites have hampered precise targeting of caspase-6. All caspases can exist in a canonical conformation, in which the substrate binds atop a β-strand platform in the 130's region. This caspase-6 region can also adopt a helical conformation that has not been seen in any other caspases. Understanding the dynamics and interconversion between the helical and strand conformations in caspase-6 is critical to fully assess its unique function and regulation. Here, hydrogen/deuterium exchange mass spectrometry indicated that caspase-6 is inherently and dramatically more conformationally dynamic than closely related caspase-7. In contrast to caspase-7, which rests constitutively in the strand conformation before and after substrate binding, the hydrogen/deuterium exchange data in the L2' and 130's regions suggested that before substrate binding, caspase-6 exists in a dynamic equilibrium between the helix and strand conformations. Caspase-6 transitions exclusively to the canonical strand conformation only upon substrate binding. Glu-135, which showed noticeably different calculated pK a values in the helix and strand conformations, appears to play a key role in the interconversion between the helix and strand conformations. Because caspase-6 has roles in several neurodegenerative diseases, exploiting the unique structural features and conformational changes identified here may provide new avenues for regulating specific caspase-6 functions for therapeutic purposes.
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Affiliation(s)
| | | | - Sergey N Savinov
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
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Lessard-Beaudoin M, Laroche M, Loudghi A, Demers MJ, Denault JB, Grenier G, Riechers SP, Wanker EE, Graham RK. Organ-specific alteration in caspase expression and STK3 proteolysis during the aging process. Neurobiol Aging 2016; 47:50-62. [DOI: 10.1016/j.neurobiolaging.2016.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 06/14/2016] [Accepted: 07/01/2016] [Indexed: 10/21/2022]
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Age-dependent differential expression of death-associated protein 6 (Daxx) in various peripheral tissues and different brain regions of C57BL/6 male mice. Biogerontology 2016; 17:817-828. [PMID: 27465500 DOI: 10.1007/s10522-016-9651-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/17/2016] [Indexed: 12/17/2022]
Abstract
Death-associated protein 6 (DAXX) is a ubiquitous protein implicated in various cellular processes such as apoptosis, tumorigenesis, development and transcription. The role of DAXX is however ambiguous and many contradictory results regarding its function in apoptosis upon various cellular stresses are described in the literature. In order to have a better understanding of the role of DAXX throughout the entire organism under physiological stress conditions, we have characterized the mRNA levels, protein expression and the proteolytic processing of DAXX in the normal aging process in peripheral organs and brain regions in C57BL/6 male mice. Overall, Daxx mRNA expression decreases with aging in the liver, kidney, heart, cortex and cerebellum. In contrast, an increase is observed in the striatum. The protein expression of DAXX and of its proteolytic fragments increases with aging in the kidney, heart and cortex. In liver and spleen, no changes are observed while in the striatum and cerebellum, certain forms increase and others decrease with age, suggesting that the functions of DAXX may be cell type dependent. This study provides important details regarding the expression and post-translational modifications of DAXX in aging in the entire organism and provides reference data for the deregulation observed in age-associated diseases.
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