151
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Lehrer S, Rheinstein PH. Constipation and Cigarette Smoking Are Independent Influences for Parkinson’s Disease. Cureus 2022; 14:e21689. [PMID: 35145822 PMCID: PMC8803378 DOI: 10.7759/cureus.21689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2022] [Indexed: 11/25/2022] Open
Abstract
Background Tobacco smokers have reduced Parkinson’s disease (PD) risk. Some patients with PD experience constipation long before they develop mobility problems, and constipation is a frequent complaint of people who try to stop smoking. Recently, the gut microbiome has been implicated in PD. Methods In the present study, we analyzed the relationship between smoking and constipation in subjects with PD and controls. We wished to determine whether the effects of smoking and constipation were independent or whether they might be interrelated. To evaluate the relationship, we used a cohort of subjects from the UK Biobank (UKB). Results In 501,174 subjects, the decreased risk of Parkinson’s disease with increased smoking was significant (p < 0.001, two-tailed Fisher’s exact test). The increased risk of constipation in subjects with PD was significant (p = 0.001, two-tailed Fisher’s exact test). Logistic regression was performed; sex, age, constipation, and smoking were the independent variables, and PD present or absent was the dependent variable. The PD odds ratio (OR) for males was 1.790 (95% confidence interval (CI): 1.629-1.966) times that for females, indicating that PD is more common in men. The risk of PD increased by 1.140 (95% CI: 1.131-1.149) with every year of age. Constipation increased the risk of PD by 4.043 (95% CI: 1.901-8.599). Smoking diminished PD risk by 0.772 (95% CI: 0.690-0.863). Drinking coffee was associated with a reduced risk of PD (OR: 0.815 (95% CI: 0.730-0.909). Drinking tea reduced PD risk by 0.979 (95% CI: 0.962-0.997) for each cup per day. The effects of sex, age, constipation, smoking, drinking coffee, and drinking tea were independent and significant. Conclusion Our analysis suggests that the favorable effect of smoking on PD is independent of the detrimental effect of constipation. Smoking reduces PD risk because it not only stimulates the bowel to empty and prevents constipation but also alters the gut microbiome. Another factor, perhaps the tobacco component diterpenoids, may be responsible for the PD risk-reducing effect.
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152
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Sun Z, Gu P, Xu H, Zhao W, Zhou Y, Zhou L, Zhang Z, Wang W, Han R, Chai X, An S. Human Umbilical Cord Mesenchymal Stem Cells Improve Locomotor Function in Parkinson’s Disease Mouse Model Through Regulating Intestinal Microorganisms. Front Cell Dev Biol 2022; 9:808905. [PMID: 35127723 PMCID: PMC8810651 DOI: 10.3389/fcell.2021.808905] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/10/2021] [Indexed: 12/18/2022] Open
Abstract
Parkinson’s disease (PD) is a progressive neurological disorder characterized by loss of neurons that synthesize dopamine, and subsequent impaired movement. Umbilical cord mesenchymal stem cells (UC-MSCs) exerted neuroprotection effects in a rodent model of PD. However, the mechanism underlying UC-MSC-generated neuroprotection was not fully elucidated. In the present study, we found that intranasal administration of UC-MSCs significantly alleviated locomotor deficits and rescued dopaminergic neurons by inhibiting neuroinflammation in a PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, a toxic agent which selectively destroys nigrostriatal neurons but does not affect dopaminergic neurons elsewhere). Furthermore, UC-MSC treatment altered gut microbiota composition characterized by decreased phylum Proteobacteria, class Gammaproteobacteria, family Enterobacteriaceae, and genus Escherichia-Shigella. In addition, the neurotransmitter dopamine in the striatum and 5-hydroxytryptamine in the colon were also modulated by UC-MSCs. Meanwhile, UC-MSCs significantly maintained intestinal goblet cells, which secrete mucus as a mechanical barrier against pathogens. Furthermore, UC-MSCs alleviate the level of TNF-α and IL-6 as well as the conversion of NF-κB expression in the colon, indicating that inflammatory responses were blocked by UC-MSCs. PICRUSt showed that some pathways including bacterial invasion of epithelial cells, fluorobenzoate degradation, and pathogenic Escherichia coli infection were significantly reversed by UC-MSCs. These data suggest that the beneficial effects were detected following UC-MSC intranasal transplantation in MPTP-treated mice. There is a possible neuroprotective role of UC-MSCs in MPTP-induced PD mice by cross talk between the brain and gut.
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Affiliation(s)
- Zhengqin Sun
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
| | - Ping Gu
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hongjun Xu
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
- Research Center, Hebei University of Chinese Medicine, Shijiazhuang, China
- College of Integrated Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Wei Zhao
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
- Research Center, Hebei University of Chinese Medicine, Shijiazhuang, China
- College of Integrated Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
- Affiliated Hospital of Hebei University of Engineering, Handan, China
| | - Yongjie Zhou
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
- Research Center, Hebei University of Chinese Medicine, Shijiazhuang, China
- College of Integrated Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Luyang Zhou
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
- Research Center, Hebei University of Chinese Medicine, Shijiazhuang, China
- College of Integrated Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Zhongxia Zhang
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
| | - Wenting Wang
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Rui Han
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiqing Chai
- Department of Neurology, The First Hospital of Hebei Medical University, Shijiazhuang, China
- *Correspondence: Xiqing Chai, ; Shengjun An,
| | - Shengjun An
- Hebei Provincial Engineering Laboratory of Plant Bioreactor Preparation Technology, Shijiazhuang, China
- Research Center, Hebei University of Chinese Medicine, Shijiazhuang, China
- College of Integrated Chinese and Western Medicine, Hebei University of Chinese Medicine, Shijiazhuang, China
- *Correspondence: Xiqing Chai, ; Shengjun An,
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153
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Abstract
The notion that autoimmune responses to α-synuclein may be involved in the pathogenesis of this disorder stems from reports that mutations in α-synuclein or certain alleles of the major histocompatibility complex (MHC) are associated with the disease and that dopaminergic and norepinephrinergic neurons in the midbrain can present antigenic epitopes. Here, we discuss recent evidence that a defined set of peptides derived from α-synuclein act as antigenic epitopes displayed by specific MHC alleles and drive helper and cytotoxic T cell responses in patients with PD. Moreover, phosphorylated α-synuclein may activate T cell responses in a less restricted manner in PD. While the roles for the acquired immune system in disease pathogenesis remain unknown, preclinical animal models and in vitro studies indicate that T cells may interact with neurons and exert effects related to neuronal death and neuroprotection. These findings suggest that therapeutics that target T cells and ameliorate the incidence or disease severity of inflammatory bowel disorders or CNS autoimmune diseases such as multiple sclerosis may be useful in PD.
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154
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Horsager J, Knudsen K, Sommerauer M. Clinical and imaging evidence of brain-first and body-first Parkinson's disease. Neurobiol Dis 2022; 164:105626. [PMID: 35031485 DOI: 10.1016/j.nbd.2022.105626] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 12/17/2022] Open
Abstract
Braak's hypothesis has been extremely influential over the last two decades. However, neuropathological and clinical evidence suggest that the model does not conform to all patients with Parkinson's disease (PD). To resolve this controversy, a new model was recently proposed; in brain-first PD, the initial α-synuclein pathology arise inside the central nervous system, likely rostral to the substantia nigra pars compacta, and spread via interconnected structures - eventually affecting the autonomic nervous system; in body-first PD, the initial pathological α-synuclein originates in the enteric nervous system with subsequent caudo-rostral propagation to the autonomic and central nervous system. By using REM-sleep behavior disorder (RBD) as a clinical identifier to distinguish between body-first PD (RBD-positive at motor symptom onset) and brain-first PD (RBD-negative at motor symptom onset), we explored the literature to evaluate clinical and imaging differences between these proposed subtypes. Body-first PD patients display: 1) a larger burden of autonomic symptoms - in particular orthostatic hypotension and constipation, 2) more frequent pathological α-synuclein in peripheral tissues, 3) more brainstem and autonomic nervous system involvement in imaging studies, 4) more symmetric striatal dopaminergic loss and motor symptoms, and 5) slightly more olfactory dysfunction. In contrast, only minor cortical metabolic alterations emerge before motor symptoms in body-first. Brain-first PD is characterized by the opposite clinical and imaging patterns. Patients with pathological LRRK2 genetic variants mostly resemble a brain-first PD profile whereas patients with GBA variants typically conform to a body-first profile. SNCA-variant carriers are equally distributed between both subtypes. Overall, the literature indicates that body-first and brain-first PD might be two distinguishable entities on some clinical and imaging markers.
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Affiliation(s)
- Jacob Horsager
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark.
| | - Karoline Knudsen
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - Michael Sommerauer
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark; Department of Neurology, University Hospital Cologne, Faculty of Medicine, University of Cologne, Köln, Germany; Institute of Neuroscience and Medicine (INM-3), Forschungszentrum Jülich, Jülich, Germany
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155
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Kramer P. Mitochondria-Microbiota Interaction in Neurodegeneration. Front Aging Neurosci 2022; 13:776936. [PMID: 35002678 PMCID: PMC8733591 DOI: 10.3389/fnagi.2021.776936] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Alzheimer’s and Parkinson’s are the two best-known neurodegenerative diseases. Each is associated with the excessive aggregation in the brain and elsewhere of its own characteristic amyloid proteins. Yet the two afflictions have much in common and often the same amyloids play a role in both. These amyloids need not be toxic and can help regulate bile secretion, synaptic plasticity, and immune defense. Moreover, when they do form toxic aggregates, amyloids typically harm not just patients but their pathogens too. A major port of entry for pathogens is the gut. Keeping the gut’s microbe community (microbiota) healthy and under control requires that our cells’ main energy producers (mitochondria) support the gut-blood barrier and immune system. As we age, these mitochondria eventually succumb to the corrosive byproducts they themselves release, our defenses break down, pathogens or their toxins break through, and the side effects of inflammation and amyloid aggregation become problematic. Although it gets most of the attention, local amyloid aggregation in the brain merely points to a bigger problem: the systemic breakdown of the entire human superorganism, exemplified by an interaction turning bad between mitochondria and microbiota.
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Affiliation(s)
- Peter Kramer
- Department of General Psychology, University of Padua, Padua, Italy
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156
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Alam MM, Yang D, Li XQ, Liu J, Back TC, Trivett A, Karim B, Barbut D, Zasloff M, Oppenheim JJ. Alpha synuclein, the culprit in Parkinson disease, is required for normal immune function. Cell Rep 2022; 38:110090. [PMID: 35021075 PMCID: PMC10258816 DOI: 10.1016/j.celrep.2021.110090] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/30/2021] [Accepted: 11/12/2021] [Indexed: 12/26/2022] Open
Abstract
Alpha-synuclein (αS) is causally involved in the development of Parkinson disease (PD); however, its role in normal vertebrate physiology has remained unknown. Recent studies demonstrate that αS is induced by noroviral infection in the enteric nervous system of children and protects mice against lethal neurotropic viral infection. Additionally, αS is a potent chemotactic activator of phagocytes. In this report, using both wild-type and αS knockout mice, we show that αS is a critical mediator of inflammatory and immune responses. αS is required for the development of a normal inflammatory response to bacterial peptidoglycan introduced into the peritoneal cavity as well as antigen-specific and T cell responses following intraperitoneal immunization. Furthermore, we show that neural cells are the sources of αS required for immune competence. Our report supports the hypothesis that αS accumulates within the nervous system of PD individuals because of an inflammatory/immune response.
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Affiliation(s)
- Md Masud Alam
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - De Yang
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
| | - Xiao-Qing Li
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Jia Liu
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Timothy Carrel Back
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Anna Trivett
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Baktiar Karim
- Molecular Histopathology Laboratory, Leidos Biomedical Research, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Denise Barbut
- Enterin Research Institute, Philadelphia, PA 19103, USA
| | - Michael Zasloff
- Enterin Research Institute, Philadelphia, PA 19103, USA; MedStar Georgetown Transplant Institute, Georgetown University Hospital, Washington, DC 20007, USA
| | - Joost J Oppenheim
- Cellular Immunology Section, Laboratory of Cancer ImmunoMetabolism, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA.
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157
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Klann EM, Dissanayake U, Gurrala A, Farrer M, Shukla AW, Ramirez-Zamora A, Mai V, Vedam-Mai V. The Gut-Brain Axis and Its Relation to Parkinson's Disease: A Review. Front Aging Neurosci 2022; 13:782082. [PMID: 35069178 PMCID: PMC8776990 DOI: 10.3389/fnagi.2021.782082] [Citation(s) in RCA: 59] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/18/2021] [Indexed: 02/02/2023] Open
Abstract
Parkinson's disease is a chronic neurodegenerative disease characterized by the accumulation of misfolded alpha-synuclein protein (Lewy bodies) in dopaminergic neurons of the substantia nigra and other related circuitry, which contribute to the development of both motor (bradykinesia, tremors, stiffness, abnormal gait) and non-motor symptoms (gastrointestinal issues, urinogenital complications, olfaction dysfunction, cognitive impairment). Despite tremendous progress in the field, the exact pathways and mechanisms responsible for the initiation and progression of this disease remain unclear. However, recent research suggests a potential relationship between the commensal gut bacteria and the brain capable of influencing neurodevelopment, brain function and health. This bidirectional communication is often referred to as the microbiome-gut-brain axis. Accumulating evidence suggests that the onset of non-motor symptoms, such as gastrointestinal manifestations, often precede the onset of motor symptoms and disease diagnosis, lending support to the potential role that the microbiome-gut-brain axis might play in the underlying pathological mechanisms of Parkinson's disease. This review will provide an overview of and critically discuss the current knowledge of the relationship between the gut microbiota and Parkinson's disease. We will discuss the role of α-synuclein in non-motor disease pathology, proposed pathways constituting the connection between the gut microbiome and the brain, existing evidence related to pre- and probiotic interventions. Finally, we will highlight the potential opportunity for the development of novel preventative measures and therapeutic options that could target the microbiome-gut-brain axis in the context of Parkinson's disease.
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Affiliation(s)
- Emily M. Klann
- Department of Epidemiology, College of Public Health and Health Professions & College of Medicine, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Upuli Dissanayake
- Department of Epidemiology, College of Public Health and Health Professions & College of Medicine, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Anjela Gurrala
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Matthew Farrer
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
| | - Aparna Wagle Shukla
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Adolfo Ramirez-Zamora
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Volker Mai
- Department of Epidemiology, College of Public Health and Health Professions & College of Medicine, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Vinata Vedam-Mai
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, United States
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
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158
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Tang Y, Zhang D, Gong X, Zheng J. Repurposing of intestinal defensins as multi-target, dual-function amyloid inhibitors via cross-seeding. Chem Sci 2022; 13:7143-7156. [PMID: 35799805 PMCID: PMC9214849 DOI: 10.1039/d2sc01447e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Amyloid formation and microbial infection are the two common pathological causes of neurogenerative diseases, including Alzheimer's disease (AD), type II diabetes (T2D), and medullary thyroid carcinoma (MTC). While significant efforts have been made to develop different prevention strategies and preclinical hits for these diseases, conventional design strategies of amyloid inhibitors are mostly limited to either a single prevention mechanism (amyloid cascade vs. microbial infection) or a single amyloid protein (Aβ, hIAPP, or hCT), which has prevented the launch of any successful drug on the market. Here, we propose and demonstrate a new “anti-amyloid and anti-bacteria” strategy to repurpose two intestinal defensins, human α-defensin 6 (HD-6) and human β-defensin 1 (HBD-1), as multiple-target, dual-function, amyloid inhibitors. Both HD-6 and HBD-1 can cross-seed with three amyloid peptides, Aβ (associated with AD), hIAPP (associated with T2D), and hCT (associated with MTC), to prevent their aggregation towards amyloid fibrils from monomers and oligomers, rescue SH-SY5Y and RIN-m5F cells from amyloid-induced cytotoxicity, and retain their original antimicrobial activity against four common bacterial strains at sub-stoichiometric concentrations. Such sequence-independent anti-amyloid and anti-bacterial functions of intestinal defensins mainly stem from their cross-interactions with amyloid proteins through amyloid-like mimicry of β-sheet associations. In a broader view, this work provides a new out-of-the-box thinking to search and repurpose a huge source of antimicrobial peptides as amyloid inhibitors, allowing the blocking of the two interlinked pathological pathways and bidirectional communication between the central nervous system and intestines via the gut–brain axis associated with neurodegenerative diseases. Amyloid formation and microbial infection are the two common pathological causes of neurogenerative diseases. Here, we proposed a new “anti-amyloid and anti-bacteria” strategy to repurpose two intestinal defensins as multiple-target, dual-function amyloid inhibitors.![]()
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Affiliation(s)
- Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Ohio, USA
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Ohio, USA
| | - Xiong Gong
- School of Polymer Science and Polymer Engineering, The University of Akron, Ohio, USA
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron, Ohio, USA
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159
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Das TK, Blasco-Conesa MP, Korf J, Honarpisheh P, Chapman MR, Ganesh BP. Bacterial Amyloid Curli Associated Gut Epithelial Neuroendocrine Activation Predominantly Observed in Alzheimer's Disease Mice with Central Amyloid-β Pathology. J Alzheimers Dis 2022; 88:191-205. [PMID: 35527554 PMCID: PMC9583710 DOI: 10.3233/jad-220106] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Substantial evidence from recent research suggests an influential and underappreciated force in Alzheimer's disease (AD) pathogenesis: the pathological signals originate from outside the brain. Pathogenic bacteria produce amyloid-like proteins "curli" that form biofilms and show functional similarities to human amyloid-β (Aβ). These proteins may contribute to neurological disease progression via signaling cascade from the gut to the brain. OBJECTIVE We propose that curli causes neuroendocrine activation from the gut to brain that promotes central Aβ pathology. METHODS PGP9.5 and TLR2 levels in response to curli in the lumen of Tg2576 AD mice were analyzed by immunohistochemical and qRT-PCR analysis. Western blot and human 3D in vitro enteroids culture systems were also used. 16S rRNA gene sequencing was used to investigate bacterial dysbiosis. RESULTS We found significant increase in bacterial-amyloid curli with elevated TLR2 at the mRNA level in the pre- and symptomatic Tg-AD gut compared to littermate WT controls. This data associates with increased gram-positive bacterial colonization in the ileum of the symptomatic AD mice. We found fundamental evidence for vagus nerve activation in response to bacterial curli. Neuroendocrine marker PGP9.5 was significantly elevated in the gut epithelium of symptomatic AD mice, and this was colocalized with increased TLR2 expression. Enteroids, 3D-human ileal mini-gut monolayer in vitro model system also revealed increase levels of TLR2 upon stimulation with purified bacterial curli fibrils. CONCLUSION These findings reveal the importance of pathological changes within the gut-vagus-brain signaling in response to luminal bacterial amyloid that might play a vital role in central Aβ pathogenesis seen in the AD brain.
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Affiliation(s)
- Tushar K. Das
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Maria P. Blasco-Conesa
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Janelle Korf
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Pedram Honarpisheh
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Matthew R. Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Bhanu P. Ganesh
- Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA,Correspondence to: Bhanu Priya Ganesh, Department of Neurology, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, USA. Tel.: +1 713 500 7429;
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160
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Preethy S, Ranganathan N, Raghavan K, Dedeepiya VD, Ikewaki N, Abraham SJ. Integrating the Synergy of the Gut Microbiome into Regenerative Medicine: Relevance to Neurological Disorders. J Alzheimers Dis 2022; 87:1451-1460. [PMID: 35466942 PMCID: PMC9277691 DOI: 10.3233/jad-220313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2022] [Indexed: 11/29/2022]
Abstract
A new paradigm of cell therapy-based approaches as a solution to several diseases caused by damage or loss of cells/tissues leading to organ failure heralded the birth of a new branch in medicine called regenerative medicine (RM), which was further fueled by in vitro cell expansion and tissue engineering (TE) technologies, including the ability to grow embryonic stem cells, induce pluripotent stem cells, and so on. RM addresses organ failure by repair, regeneration, or restoration, rejuvenation using cells, stem cells, or progenitor cells as tools having added cell-derived products also as a tool, and extracellular matrix component-based support, either direct or indirect (e.g., matrix induced autologous chondrocyte implantation) using scaffolds. Now, the main objective of RM is to solve the functional loss of cells that have evolved from cells as tools to cell-derived factors and scaffolds per se as tools. In this context, an important yet indispensable group of cells that constitute the major portion of the human body in terms of the number of cells having several essential roles to play, both directly and indirectly, starting from digestion and the immune system to the growing evidence of influencing neuronal function, aging, and carcinogenesis has been ignored. We would like to focus on these in this review as they should essentially be considered as a tool of RM, especially for neurological disorders for their vital role. What we are indicating is the second genome or the gut microbiome.
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Affiliation(s)
- Senthilkumar Preethy
- Fujio-Eiji Academic Terrain (FEAT), Nichi-In Centre for Regenerative Medicine (NCRM), Chennai, India
| | | | - Kadalraja Raghavan
- Department of Paediatric Neurology, Jesuit Antonyraj memorial Inter-disciplinary Centre for Advanced Recovery and Education (JAICARE), Madurai, India
- Department of Paediatric Neurology, Sarvee Integra Private Limited, Chennai, India
| | | | - Nobunao Ikewaki
- Department of Medical Life Science, Kyushu University of Health and Welfare, Nobeoka, Japan
- Institute of Immunology, Junsei Educational Institute, Nobeoka, Japan
| | - Samuel J.K. Abraham
- Mary-Yoshio Translational Hexagon (MYTH), Nichi-In Centre for Regenerative Medicine (NCRM), Chennai, India
- Centre for Advancing Clinical Research (CACR), University of Yamanashi - School of Medicine, Chuo, Japan
- Antony- Xavier Interdisciplinary Scholastics (AXIS), GN Corporation Co. Ltd., Kofu, Japan
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161
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Zhong SR, Kuang Q, Zhang F, Chen B, Zhong ZG. Functional roles of the microbiota-gut-brain axis in Alzheimer’s disease: Implications of gut microbiota-targeted therapy. Transl Neurosci 2021; 12:581-600. [PMID: 35070442 PMCID: PMC8724360 DOI: 10.1515/tnsci-2020-0206] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023] Open
Abstract
Increasing scientific evidence demonstrates that the gut microbiota influences normal physiological homeostasis and contributes to pathogenesis, ranging from obesity to neurodegenerative diseases, such as Alzheimer’s disease (AD). Gut microbiota can interact with the central nervous system (CNS) through the microbiota-gut-brain axis. The interaction is mediated by microbial secretions, metabolic interventions, and neural stimulation. Here, we review and summarize the regulatory pathways (immune, neural, neuroendocrine, or metabolic systems) in the microbiota-gut-brain axis in AD pathogenesis. Besides, we highlight the significant roles of the intestinal epithelial barrier and blood–brain barrier (BBB) in the microbiota-gut-brain axis. During the progression of AD, there is a gradual shift in the gut microbiota and host co-metabolic relationship, leading to gut dysbiosis, and the imbalance of microbial secretions and metabolites, such as lipopolysaccharides (LPS) and short-chain fatty acids (SCFAs). These products may affect the CNS metabolic state and immune balance through the microbiota-gut-brain axis. Further, we summarize the potential microbiota-gut-brain axis-targeted therapy including carbohydrates, probiotics, dietary measures, and propose new strategies toward the development of anti-AD drugs. Taken together, the data in this review suggest that remodeling the gut microbiota may present a tractable strategy in the management and development of new therapeutics against AD and other neurodegenerative diseases.
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Affiliation(s)
- Si-Ran Zhong
- School of Health Medicine, Guangzhou Huashang College , Guangzhou , 511300 , People’s Republic of China
| | - Qi Kuang
- School of Health Medicine, Guangzhou Huashang College , Guangzhou , 511300 , People’s Republic of China
| | - Fan Zhang
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine , Guangzhou , 510006 , People’s Republic of China
| | - Ben Chen
- Scientific Research Center of Traditional Chinese Medicine, Guangxi University of Chinese Medicine , Nanning City , 530200, Guangxi Zhuang Autonomous Region , People’s Republic of China
| | - Zhen-Guo Zhong
- Scientific Research Center of Traditional Chinese Medicine, Guangxi University of Chinese Medicine , Nanning City , 530200, Guangxi Zhuang Autonomous Region , People’s Republic of China
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162
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Balan Y, Gaur A, Sakthivadivel V, Kamble B, Sundaramurthy R. Is the Gut Microbiota a Neglected Aspect of Gut and Brain Disorders? Cureus 2021; 13:e19740. [PMID: 34938619 PMCID: PMC8684598 DOI: 10.7759/cureus.19740] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2021] [Indexed: 12/13/2022] Open
Abstract
The gut microbiota is a quickly developing bacterial ecosystem with biodiversity. It is an adaptive immunity that varies with food intake, environmental conditions, and human habits, among other factors. Various external stimuli, such as drugs, can influence the gut microbial environment and lead to gut dysbiosis. Recently, gut dysbiosis has been identified as an important factor that leads to several diseases either by the released metabolites or by the gut neuronal connection. In brain disorders, gut dysbiosis is involved in neuropsychiatric manifestations, including autism spectrum disorder, anxiety, and depression by interfering with neurotransmitter homeostasis, and neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease by releasing abnormal metabolites from the gut. Gut dysbiosis has been documented in gut disorders, including inflammatory bowel disease or irritable bowel syndrome. Immune cells in the gut are modulated by external factors such as stress, diet, and drugs to produce inflammatory cytokines, including interleukins (IL-4, IL-6, IL-17, IL-23, etc.). Inflammatory cytokines lead to a cascade of events, which lead to various ailments in the bowel. Beneficial bacteria in the form of probiotics ameliorate the condition and have healthful effects in disease conditions. This warrants further research to identify newer therapeutic strategies for diseases that cannot be cured or are difficult to treat.
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Affiliation(s)
- Yuvaraj Balan
- Department of Biochemistry, All India Institute of Medical Sciences, Bibinagar, Bibinagar, IND
| | - Archana Gaur
- Department of Physiology, All India Institute of Medical Sciences, Bibinagar, Bibinagar, IND
| | | | - Bhushan Kamble
- Department of Community and Family Medicine, All India Institute of Medical Sciences, Bibinagar, Bibinagar, IND
| | - Raja Sundaramurthy
- Department of Microbiology, All India Institute of Medical Sciences, Bibinagar, Bibinagar, IND
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163
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Gorecki AM, Anyaegbu CC, Anderton RS. TLR2 and TLR4 in Parkinson's disease pathogenesis: the environment takes a toll on the gut. Transl Neurodegener 2021; 10:47. [PMID: 34814947 PMCID: PMC8609261 DOI: 10.1186/s40035-021-00271-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/29/2021] [Indexed: 02/08/2023] Open
Abstract
Parkinson's disease (PD) is an incurable, devastating disorder that is characterized by pathological protein aggregation and neurodegeneration in the substantia nigra. In recent years, growing evidence has implicated the gut environment and the gut-brain axis in the pathogenesis and progression of PD, especially in a subset of people who exhibit prodromal gastrointestinal dysfunction. Specifically, perturbations of gut homeostasis are hypothesized to contribute to α-synuclein aggregation in enteric neurons, which may spread to the brain over decades and eventually result in the characteristic central nervous system manifestations of PD, including neurodegeneration and motor impairments. However, the mechanisms linking gut disturbances and α-synuclein aggregation are still unclear. A plethora of research indicates that toll-like receptors (TLRs), especially TLR2 and TLR4, are critical mediators of gut homeostasis. Alongside their established role in innate immunity throughout the body, studies are increasingly demonstrating that TLR2 and TLR4 signalling shapes the development and function of the gut and the enteric nervous system. Notably, TLR2 and TLR4 are dysregulated in patients with PD, and may thus be central to early gut dysfunction in PD. To better understand the putative contribution of intestinal TLR2 and TLR4 dysfunction to early α-synuclein aggregation and PD, we critically discuss the role of TLR2 and TLR4 in normal gut function as well as evidence for altered TLR2 and TLR4 signalling in PD, by reviewing clinical, animal model and in vitro research. Growing evidence on the immunological aetiology of α-synuclein aggregation is also discussed, with a focus on the interactions of α-synuclein with TLR2 and TLR4. We propose a conceptual model of PD pathogenesis in which microbial dysbiosis alters the permeability of the intestinal barrier as well as TLR2 and TLR4 signalling, ultimately leading to a positive feedback loop of chronic gut dysfunction promoting α-synuclein aggregation in enteric and vagal neurons. In turn, α-synuclein aggregates may then migrate to the brain via peripheral nerves, such as the vagal nerve, to contribute to neuroinflammation and neurodegeneration typically associated with PD.
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Affiliation(s)
- Anastazja M Gorecki
- School of Biological Science, University of Western Australia, Crawley, WA, Australia.
- Neurodegenerative Disorders Research Group, Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.
| | - Chidozie C Anyaegbu
- Curtin Health Innovation Research Institute, Ralph and Patricia Sarich Neuroscience Research Institute, Curtin University, Nedlands, WA, Australia
| | - Ryan S Anderton
- Faculty of Medicine, Nursing and Midwifery and Faculty of Health Sciences, University of Notre Dame Australia, Fremantle, WA, Australia
- School of Nursing, Midwifery, Health Sciences and Physiotherapy, University of Notre Dame Australia, Fremantle, WA, Australia
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164
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Toh TS, Chong CW, Lim SY, Bowman J, Cirstea M, Lin CH, Chen CC, Appel-Cresswell S, Finlay BB, Tan AH. Gut microbiome in Parkinson's disease: New insights from meta-analysis. Parkinsonism Relat Disord 2021; 94:1-9. [PMID: 34844021 DOI: 10.1016/j.parkreldis.2021.11.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 11/05/2021] [Accepted: 11/13/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Gut microbiome alterations have been reported in Parkinson's disease (PD), but with heterogenous findings, likely due to differences in study methodology and population. We investigated the main microbiome alterations in PD, their correlations with disease severity, and the impact of study and geographical differences. METHODS After systematic screening, raw 16S rRNA gene sequences were obtained from ten case-control studies totaling 1703 subjects (969 PD, 734 non-PD controls; seven predominantly Caucasian and three predominantly non-Caucasian cohorts). Quality-filtered gene sequences were analyzed using a phylogenetic placement approach, which precludes the need for the sequences to be sourced from similar regions in the 16S rRNA gene, thus allowing a direct comparison between studies. Differences in microbiome composition and correlations with clinical variables were analyzed using multivariate statistics. RESULTS Study and geography accounted for the largest variations in gut microbiome composition. Microbiome composition was more similar for subjects from the same study than those from different studies with the same disease status. Microbiome composition significantly differed between Caucasian and non-Caucasian populations. After accounting for study differences, microbiome composition was significantly different in PD vs. controls (albeit with a marginal effect size), with several distinctive features including increased abundances of Megasphaera and Akkermansia, and reduced Roseburia. Several bacterial genera correlated with PD motor severity, motor response complications and cognitive function. CONCLUSION Consistent microbial features in PD merit further investigation. The large variations in microbiome findings of PD patients underscore the need for greater harmonization of future research, and personalized approaches in designing microbial-directed therapeutics.
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Affiliation(s)
- Tzi Shin Toh
- Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Mah Pooi Soo & Tan Chin Nam Centre for Parkinson's & Related Disorders, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Selangor, Malaysia.
| | - Shen-Yang Lim
- Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Mah Pooi Soo & Tan Chin Nam Centre for Parkinson's & Related Disorders, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Jeff Bowman
- Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, California, USA; Center for Microbiome Innovation, UC San Diego, California, USA
| | - Mihai Cirstea
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, UBC, Vancouver, British Columbia, Canada
| | - Chin-Hsien Lin
- Department of Neurology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chieh-Chang Chen
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Silke Appel-Cresswell
- Pacific Parkinson's Research Centre and Djavad Mowafaghian Centre for Brain Health, UBC, Vancouver, British Columbia, Canada; Division of Neurology, Faculty of Medicine, UBC, Vancouver, British Columbia, Canada
| | - B Brett Finlay
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada; Michael Smith Laboratories, UBC, Vancouver, British Columbia, Canada; Department of Biochemistry and Molecular Biology, UBC, Vancouver, British Columbia, Canada
| | - Ai Huey Tan
- Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia; Mah Pooi Soo & Tan Chin Nam Centre for Parkinson's & Related Disorders, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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165
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Horsager J, Knudsen K, Borghammer P. Radionuclide Imaging of the Gut-Brain Axis in Parkinson Disease. J Nucl Med 2021; 62:1504-1505. [PMID: 34301776 PMCID: PMC8612321 DOI: 10.2967/jnumed.121.262300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/29/2021] [Indexed: 11/16/2022] Open
Affiliation(s)
- Jacob Horsager
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - Karoline Knudsen
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
| | - Per Borghammer
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark
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166
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Morgan GJ. Transient disorder along pathways to amyloid. Biophys Chem 2021; 281:106711. [PMID: 34839162 DOI: 10.1016/j.bpc.2021.106711] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 01/15/2023]
Abstract
High-resolution structures of amyloid fibrils formed from normally-folded proteins have revealed non-native conformations of the polypeptide chains. Attaining these conformations apparently requires transition from the native state via a highly disordered conformation, in contrast to earlier models that posited a role for assembly of partially folded proteins. Modifications or interactions that extend the lifetime or constrain the conformations of these disordered states could act to enhance or suppress amyloid formation. Understanding how the properties of both the folded and transiently disordered structural ensembles influence the process of amyloid formation is a substantial challenge, but research into the properties of intrinsically disordered proteins will deliver important insights.
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Affiliation(s)
- Gareth J Morgan
- The Amyloidosis Center and Section of Hematology and Medical Oncology, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
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167
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Small Intestinal Bacterial Overgrowth as Potential Therapeutic Target in Parkinson's Disease. Int J Mol Sci 2021; 22:ijms222111663. [PMID: 34769091 PMCID: PMC8584211 DOI: 10.3390/ijms222111663] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/17/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
Increasing evidence suggests that the gut microbiota and the brain are closely connected via the so-called gut–brain axis. Small intestinal bacterial overgrowth (SIBO) is a gut dysbiosis in which the small intestine is abundantly colonized by bacteria that are typically found in the colon. Though not a disease, it may result in intestinal symptoms caused by the accumulation of microbial gases in the intestine. Intestinal inflammation, malabsorption and vitamin imbalances may also develop. SIBO can be eradicated by one or several courses of antibiotics but reappears if the predisposing condition persists. Parkinson’s disease (PD) is a common neurodegenerative proteinopathy for which disease modifying interventions are not available. Sporadic forms may start in the gut years before the development of clinical features. Increased gastrointestinal transit time is present in most people with PD early during the course of the disease, predisposing to gut dysbiosis, including SIBO. The role that gut dysbiosis may play in the etiopathogenesis of PD is not fully understood yet. Here, we discuss the possibility that SIBO could contribute to the progression of PD, by promoting or preventing neurodegeneration, thus being a potential target for treatments aiming at slowing down the progression of PD. The direct symptomatic impact of SIBO and its impact on symptomatic medication are also briefly discussed.
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168
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Microbiota-brain interactions: Moving toward mechanisms in model organisms. Neuron 2021; 109:3930-3953. [PMID: 34653349 DOI: 10.1016/j.neuron.2021.09.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/03/2021] [Accepted: 09/17/2021] [Indexed: 02/07/2023]
Abstract
Changes in the microbiota are associated with alterations in nervous system structure-function and behavior and have been implicated in the etiology of neuropsychiatric and neurodegenerative disorders. Most of these studies have centered on mammalian models due to their phylogenetic proximity to humans. Indeed, the germ-free mouse has been a particularly useful model organism for investigating microbiota-brain interactions. However, microbiota-brain axis research on simpler genetic model organisms with a vast and diverse scientific toolkit (zebrafish, Drosophila melanogaster, and Caenorhabditis elegans) is now also coming of age. In this review, we summarize the current state of microbiota-brain axis research in rodents and humans, and then we elaborate and discuss recent research on the neurobiological and behavioral effects of the microbiota in the model systems of fish, flies, and worms. We propose that a cross-species, holistic and mechanistic approach to unravel the microbiota-brain communication is an essential step toward rational microbiota-based therapeutics to combat brain disorders.
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169
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Sun J, Huang T, Debelius JW, Fang F. Gut microbiome and amyotrophic lateral sclerosis: A systematic review of current evidence. J Intern Med 2021; 290:758-788. [PMID: 34080741 DOI: 10.1111/joim.13336] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS), characterized by a loss of motor neurons in the brain and spinal cord, is a relatively rare but currently incurable neurodegenerative disease. The global incidence of ALS is estimated as 1.75 per 100,000 person-years and the global prevalence is estimated as 4.1-8.4 per 100,000 individuals. Contributions from outside the central nervous system to the etiology of ALS have been increasingly recognized. Gut microbiome is one of the most quickly growing fields of research for ALS. In this article, we performed a comprehensive review of the results from existing animal and human studies, to provide an up-to-date summary of the current research on gut microbiome and ALS. In brief, we found relatively consistent results from animal studies, suggesting an altered gut microbiome composition in experimental ALS. Publication bias might however be a concern. Findings from human studies are largely inconclusive. A few animal and human studies demonstrated the usefulness of intervention with microbial-derived metabolites in modulating the disease progression of ALS. We discussed potential methodological concerns in these studies, including study design, statistical power, handling process of biospecimens and sequencing data, as well as statistical methods and interpretation of results. Finally, we made a few proposals for continued microbiome research in ALS, with the aim to provide valid, reproducible, and translatable findings.
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Affiliation(s)
- Jiangwei Sun
- Unit of Integrative Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Tingting Huang
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.,Department of Radiation Oncology, The First Affiliated Hospital of Guangxi Medical University, Nanning, People's Republic of China
| | - Justine W Debelius
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Fang Fang
- Unit of Integrative Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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170
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Mehra S, Gadhe L, Bera R, Sawner AS, Maji SK. Structural and Functional Insights into α-Synuclein Fibril Polymorphism. Biomolecules 2021; 11:1419. [PMID: 34680054 PMCID: PMC8533119 DOI: 10.3390/biom11101419] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 12/21/2022] Open
Abstract
Abnormal accumulation of aggregated α-synuclein (α-Syn) is seen in a variety of neurodegenerative diseases, including Parkinson's disease (PD), multiple system atrophy (MSA), dementia with Lewy body (DLB), Parkinson's disease dementia (PDD), and even subsets of Alzheimer's disease (AD) showing Lewy-body-like pathology. These synucleinopathies exhibit differences in their clinical and pathological representations, reminiscent of prion disorders. Emerging evidence suggests that α-Syn self-assembles and polymerizes into conformationally diverse polymorphs in vitro and in vivo, similar to prions. These α-Syn polymorphs arising from the same precursor protein may exhibit strain-specific biochemical properties and the ability to induce distinct pathological phenotypes upon their inoculation in animal models. In this review, we discuss clinical and pathological variability in synucleinopathies and several aspects of α-Syn fibril polymorphism, including the existence of high-resolution molecular structures and brain-derived strains. The current review sheds light on the recent advances in delineating the structure-pathogenic relationship of α-Syn and how diverse α-Syn molecular polymorphs contribute to the existing clinical heterogeneity in synucleinopathies.
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Affiliation(s)
- Surabhi Mehra
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India; (L.G.); (R.B.); (A.S.S.)
| | | | | | | | - Samir K. Maji
- Department of Biosciences and Bioengineering, IIT Bombay, Powai, Mumbai 400076, India; (L.G.); (R.B.); (A.S.S.)
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171
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Parkinson's disease and the gut: Models of an emerging relationship. Acta Biomater 2021; 132:325-344. [PMID: 33857691 DOI: 10.1016/j.actbio.2021.03.071] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 12/17/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disease characterized by a progressive loss of fine motor function that impacts 1-2 out of 1,000 people. PD occurs predominately late in life and lacks a definitive biomarker for early detection. Recent cross-disciplinary progress has implicated the gut as a potential origin of PD pathogenesis. The gut-origin hypothesis has motivated research on gut PD pathology and transmission to the brain, especially during the prodromal stage (10-20 years before motor symptom onset). Early findings have revealed several possible triggers for Lewy pathology - the pathological hallmark of PD - in the gut, suggesting that microbiome and epithelial interactions may play a greater than appreciated role. But the mechanisms driving Lewy pathology and gut-brain transmission in PD remain unknown. Development of artificial α-Synuclein aggregates (α-Syn preformed fibrils) and animal disease models have recapitulated features of PD progression, enabling for the first time, controlled investigation of the gut-origin hypothesis. However, the role of specific cells in PD transmission, such as neurons, remains limited and requires in vitro models for controlled evaluation and perturbation. Human cell populations, three-dimensional organoids, and microfluidics as discovery platforms inch us closer to improving existing treatment for patients by providing platforms for discovery and screening. This review includes a discussion of PD pathology, conventional treatments, in vivo and in vitro models, and future directions. STATEMENT OF SIGNIFICANCE: Parkinson's Disease remains a common neurodegenerative disease with palliative versus causal treatments. Recently, the gut-origin hypothesis, where Parkinson's disease is thought to originate and spread from the gut to the brain, has gained traction as a field of investigation. However, despite the wealth of studies and innovative approaches to accelerate the field, there remains a need for in vitro tools to enable fundamental biological understanding of disease progression, and compound screening and efficacy. In this review, we present a historical perspective of Parkinson's Disease pathogenesis, detection, and conventional therapy, animal and human models investigating the gut-origin hypothesis, in vitro models to enable controlled discovery, and future outlooks for this blossoming field.
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172
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Munoz-Pinto MF, Empadinhas N, Cardoso SM. The neuromicrobiology of Parkinson's disease: A unifying theory. Ageing Res Rev 2021; 70:101396. [PMID: 34171417 DOI: 10.1016/j.arr.2021.101396] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/11/2021] [Accepted: 06/19/2021] [Indexed: 02/07/2023]
Abstract
Recent evidence confirms that PD is indeed a multifactorial disease with different aetiologies and prodromal symptomatology that likely depend on the initial trigger. New players with important roles as triggers, facilitators and aggravators of the PD neurodegenerative process have re-emerged in the last few years, the microbes. Having evolved in association with humans for ages, microbes and their products are now seen as fundamental regulators of human physiology with disturbances in their balance being increasingly accepted to have a relevant impact on the progression of disease in general and on PD in particular. In this review, we comprehensively address early studies that have directly or indirectly linked bacteria or other infectious agents to the onset and progression of PD, from the earliest suspects to the most recent culprits, the gut microbiota. The quest for effective treatments to arrest PD progression must inevitably address the different interactions between microbiota and human cells, and naturally consider the gut-brain axis. The comprehensive characterization of such mechanisms will help design innovative bacteriotherapeutic approaches to selectively shape the gut microbiota profile ultimately to halt PD progression. The present review describes our current understanding of the role of microorganisms and their endosymbiotic relatives, the mitochondria, in inducing, facilitating, or aggravating PD pathogenesis.
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173
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Hanslik KL, Marino KM, Ulland TK. Modulation of Glial Function in Health, Aging, and Neurodegenerative Disease. Front Cell Neurosci 2021; 15:718324. [PMID: 34531726 PMCID: PMC8439422 DOI: 10.3389/fncel.2021.718324] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/27/2021] [Indexed: 01/15/2023] Open
Abstract
In the central nervous system (CNS), glial cells, such as microglia and astrocytes, are normally associated with support roles including contributions to energy metabolism, synaptic plasticity, and ion homeostasis. In addition to providing support for neurons, microglia and astrocytes function as the resident immune cells in the brain. The glial function is impacted by multiple aspects including aging and local CNS changes caused by neurodegeneration. During aging, microglia and astrocytes display alterations in their homeostatic functions. For example, aged microglia and astrocytes exhibit impairments in the lysosome and mitochondrial function as well as in their regulation of synaptic plasticity. Recent evidence suggests that glia can also alter the pathology associated with many neurodegenerative disorders including Alzheimer's disease (AD) and Parkinson's disease (PD). Shifts in the microbiome can impact glial function as well. Disruptions in the microbiome can lead to aberrant microglial and astrocytic reactivity, which can contribute to an exacerbation of disease and neuronal dysfunction. In this review, we will discuss the normal physiological functions of microglia and astrocytes, summarize novel findings highlighting the role of glia in aging and neurodegenerative diseases, and examine the contribution of microglia and astrocytes to disease progression.
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Affiliation(s)
- Kendra L. Hanslik
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
| | - Kaitlyn M. Marino
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
| | - Tyler K. Ulland
- Neuroscience Training Program, University of Wisconsin, Madison, WI, United States
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI, United States
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174
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Abstract
Accumulating evidence links the gut microbiome to neuronal functions in the brain. Given the increasing prevalence of brain disorders, there is a critical need to understand how gut microbes impact neuronal functions so that targeted therapeutic interventions can be developed. In this commentary, we discuss what makes the nematode Caenorhabditiselegans a valuable model for dissecting the molecular basis of gut microbiome-brain interactions. With a fully mapped neuronal circuitry, C. elegans is an effective model for studying signaling of the nervous system in a context that bears translational relevance to human disease. We highlight C. elegans as a potent but underexploited tool to interrogate the influence of the bacterial variable on the complex equation of the nervous system. We envision that routine use of gnotobiotic C. elegans to examine the gut–brain axis will be an enabling technology for the development of novel therapeutic interventions for brain diseases.
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175
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Hill AE, Wade-Martins R, Burnet PWJ. What Is Our Understanding of the Influence of Gut Microbiota on the Pathophysiology of Parkinson's Disease? Front Neurosci 2021; 15:708587. [PMID: 34512244 PMCID: PMC8432298 DOI: 10.3389/fnins.2021.708587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/26/2021] [Indexed: 12/12/2022] Open
Abstract
Microbiota have increasingly become implicated in predisposition to human diseases, including neurodegenerative disorders such as Parkinson's disease (PD). Traditionally, a central nervous system (CNS)-centric approach to understanding PD has predominated; however, an association of the gut with PD has existed since Parkinson himself reported the disease. The gut-brain axis refers to the bidirectional communication between the gastrointestinal tract (GIT) and the brain. Gut microbiota dysbiosis, reported in PD patients, may extend this to a microbiota-gut-brain axis. To date, mainly the bacteriome has been investigated. The change in abundance of bacterial products which accompanies dysbiosis is hypothesised to influence PD pathophysiology via multiple mechanisms which broadly centre on inflammation, a cause of alpha-synuclein (a-syn) misfolding. Two main routes are hypothesised by which gut microbiota can influence PD pathophysiology, the neural and humoral routes. The neural route involves a-syn misfolding peripherally in the enteric nerves which can then be transported to the brain via the vagus nerve. The humoral route involves transportation of bacterial products and proinflammatory cytokines from the gut via the circulation which can cause central a-syn misfolding by inducing neuroinflammation. This article will assess whether the current literature supports gut bacteria influencing PD pathophysiology via both routes.
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Affiliation(s)
- Amaryllis E. Hill
- Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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176
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Wittung-Stafshede P. Gut power: Modulation of human amyloid formation by amyloidogenic proteins in the gastrointestinal tract. Curr Opin Struct Biol 2021; 72:33-38. [PMID: 34450484 DOI: 10.1016/j.sbi.2021.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/10/2021] [Accepted: 07/19/2021] [Indexed: 01/06/2023]
Abstract
Protein assembly into amyloid fibers underlies many neurodegenerative disorders. In Parkinson's disease, amyloid formation of α-synuclein is linked to brain cell death. The gut-brain axis plays a key role in Parkinson's disease, and initial α-synuclein amyloid formation may occur distant from the brain. Because different amyloidogenic proteins can cross-seed, and α-synuclein is expressed outside the brain, amyloids present in the gut (from food products and secreted by microbiota) may modulate α-synuclein amyloid formation via direct interactions. I here describe existing such data that only began to appear in the literature in the last few years. The striking, but limited, data set-spanning from acceleration to inhibition-calls for additional investigations that may unravel disease mechanisms as well as new treatments.
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Affiliation(s)
- Pernilla Wittung-Stafshede
- Department of Biology and Biological Engineering, Chalmers University of Technology, S-41296, Gothenburg, Sweden.
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177
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Wang C, Lau CY, Ma F, Zheng C. Genome-wide screen identifies curli amyloid fibril as a bacterial component promoting host neurodegeneration. Proc Natl Acad Sci U S A 2021; 118:e2106504118. [PMID: 34413194 PMCID: PMC8403922 DOI: 10.1073/pnas.2106504118] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Growing evidence indicates that gut microbiota play a critical role in regulating the progression of neurodegenerative diseases such as Parkinson's disease. The molecular mechanism underlying such microbe-host interaction is unclear. In this study, by feeding Caenorhabditis elegans expressing human α-syn with Escherichia coli knockout mutants, we conducted a genome-wide screen to identify bacterial genes that promote host neurodegeneration. The screen yielded 38 genes that fall into several genetic pathways including curli formation, lipopolysaccharide assembly, and adenosylcobalamin synthesis among others. We then focused on the curli amyloid fibril and found that genetically deleting or pharmacologically inhibiting the curli major subunit CsgA in E. coli reduced α-syn-induced neuronal death, restored mitochondrial health, and improved neuronal functions. CsgA secreted by the bacteria colocalized with α-syn inside neurons and promoted α-syn aggregation through cross-seeding. Similarly, curli also promoted neurodegeneration in C. elegans models of Alzheimer's disease, amyotrophic lateral sclerosis, and Huntington's disease and in human neuroblastoma cells.
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Affiliation(s)
- Chenyin Wang
- School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chun Yin Lau
- School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Fuqiang Ma
- School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chaogu Zheng
- School of Biological Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, China
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178
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Innate immunity to prions: anti-prion systems turn a tsunami of prions into a slow drip. Curr Genet 2021; 67:833-847. [PMID: 34319422 DOI: 10.1007/s00294-021-01203-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 12/17/2022]
Abstract
The yeast prions (infectious proteins) [URE3] and [PSI+] are essentially non-functional (or even toxic) amyloid forms of Ure2p and Sup35p, whose normal function is in nitrogen catabolite repression and translation termination, respectively. Yeast has an array of systems working in normal cells that largely block infection with prions, block most prion formation, cure most nascent prions and mitigate the toxic effects of those prions that escape the first three types of systems. Here we review recent progress in defining these anti-prion systems, how they work and how they are regulated. Polymorphisms of the prion domains partially block infection with prions. Ribosome-associated chaperones ensure proper folding of nascent proteins, thus reducing [PSI+] prion formation and curing many [PSI+] variants that do form. Btn2p is a sequestering protein which gathers [URE3] amyloid filaments to one place in the cells so that the prion is often lost by progeny cells. Proteasome impairment produces massive overexpression of Btn2p and paralog Cur1p, resulting in [URE3] curing. Inversely, increased proteasome activity, by derepression of proteasome component gene transcription or by 60S ribosomal subunit gene mutation, prevents prion curing by Btn2p or Cur1p. The nonsense-mediated decay proteins (Upf1,2,3) cure many nascent [PSI+] variants by associating with Sup35p directly. Normal levels of the disaggregating chaperone Hsp104 can also cure many [PSI+] prion variants. By keeping the cellular levels of certain inositol polyphosphates / pyrophosphates low, Siw14p cures certain [PSI+] variants. It is hoped that exploration of the yeast innate immunity to prions will lead to discovery of similar systems in humans.
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179
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Tan LY, Yeo XY, Bae HG, Lee DPS, Ho RC, Kim JE, Jo DG, Jung S. Association of Gut Microbiome Dysbiosis with Neurodegeneration: Can Gut Microbe-Modifying Diet Prevent or Alleviate the Symptoms of Neurodegenerative Diseases? Life (Basel) 2021; 11:698. [PMID: 34357070 PMCID: PMC8305650 DOI: 10.3390/life11070698] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/11/2022] Open
Abstract
The central nervous system was classically perceived as anatomically and functionally independent from the other visceral organs. But in recent decades, compelling evidence has led the scientific community to place a greater emphasis on the role of gut microbes on the brain. Pathological observations and early gastrointestinal symptoms highlighted that gut dysbiosis likely precedes the onset of cognitive deficits in Alzheimer's disease (AD) and Parkinson's disease (PD) patients. The delicate balance in the number and functions of pathogenic microbes and alternative probiotic populations is critical in the modulation of systemic inflammation and neuronal health. However, there is limited success in restoring healthy microbial biodiversity in AD and PD patients with general probiotics interventions and fecal microbial therapies. Fortunately, the gut microflora is susceptible to long-term extrinsic influences such as lifestyle and dietary choices, providing opportunities for treatment through comparatively individual-specific control of human behavior. In this review, we examine the impact of restrictive diets on the gut microbiome populations associated with AD and PD. The overall evidence presented supports that gut dysbiosis is a plausible prelude to disease onset, and early dietary interventions are likely beneficial for the prevention and treatment of progressive neurodegenerative diseases.
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Affiliation(s)
- Li Yang Tan
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138667, Singapore; (L.Y.T.); (X.Y.Y.)
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
| | - Xin Yi Yeo
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138667, Singapore; (L.Y.T.); (X.Y.Y.)
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
| | - Han-Gyu Bae
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea;
| | - Delia Pei Shan Lee
- Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore 117542, Singapore;
| | - Roger C. Ho
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
- Institute for Health Innovation & Technology (iHealthtech), National University of Singapore, Singapore 117599, Singapore
| | - Jung Eun Kim
- Department of Food Science and Technology, Faculty of Science, National University of Singapore, Singapore 117542, Singapore;
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea;
| | - Sangyong Jung
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore 138667, Singapore; (L.Y.T.); (X.Y.Y.)
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
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180
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Perni M, Mannini B, Xu CK, Kumita JR, Dobson CM, Chiti F, Vendruscolo M. Exogenous misfolded protein oligomers can cross the intestinal barrier and cause a disease phenotype in C. elegans. Sci Rep 2021; 11:14391. [PMID: 34257326 PMCID: PMC8277765 DOI: 10.1038/s41598-021-93527-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023] Open
Abstract
Misfolded protein oligomers are increasingly recognized as highly cytotoxic agents in a wide range of human disorders associated with protein aggregation. In this study, we assessed the possible uptake and resulting toxic effects of model protein oligomers administered to C. elegans through the culture medium. We used an automated machine-vision, high-throughput screening procedure to monitor the phenotypic changes in the worms, in combination with confocal microscopy to monitor the diffusion of the oligomers, and oxidative stress assays to detect their toxic effects. Our results suggest that the oligomers can diffuse from the intestinal lumen to other tissues, resulting in a disease phenotype. We also observed that pre-incubation of the oligomers with a molecular chaperone (αB-crystallin) or a small molecule inhibitor of protein aggregation (squalamine), reduced the oligomer absorption. These results indicate that exogenous misfolded protein oligomers can be taken up by the worms from their environment and spread across tissues, giving rise to pathological effects in regions distant from their place of absorbance.
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Affiliation(s)
- Michele Perni
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Benedetta Mannini
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Catherine K Xu
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Janet R Kumita
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Christopher M Dobson
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
| | - Fabrizio Chiti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK.
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181
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Trichka J, Zou WQ. Modulation of Neuroinflammation by the Gut Microbiota in Prion and Prion-Like Diseases. Pathogens 2021; 10:887. [PMID: 34358037 PMCID: PMC8308761 DOI: 10.3390/pathogens10070887] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 06/30/2021] [Accepted: 07/10/2021] [Indexed: 12/29/2022] Open
Abstract
The process of neuroinflammation contributes to the pathogenic mechanism of many neurodegenerative diseases. The deleterious attributes of neuroinflammation involve aberrant and uncontrolled activation of glia, which can result in damage to proximal brain parenchyma. Failure to distinguish self from non-self, as well as leukocyte reaction to aggregation and accumulation of proteins in the CNS, are the primary mechanisms by which neuroinflammation is initiated. While processes local to the CNS may instigate neurodegenerative disease, the existence or dysregulation of systemic homeostasis can also serve to improve or worsen CNS pathologies, respectively. One fundamental component of systemic homeostasis is the gut microbiota, which communicates with the CNS via microbial metabolite production, the peripheral nervous system, and regulation of tryptophan metabolism. Over the past 10-15 years, research focused on the microbiota-gut-brain axis has culminated in the discovery that dysbiosis, or an imbalance between commensal and pathogenic gut bacteria, can promote CNS pathologies. Conversely, a properly regulated and well-balanced microbiome supports CNS homeostasis and reduces the incidence and extent of pathogenic neuroinflammation. This review will discuss the role of the gut microbiota in exacerbating or alleviating neuroinflammation in neurodegenerative diseases, and potential microbiota-based therapeutic approaches to reduce pathology in diseased states.
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Affiliation(s)
| | - Wen-Quan Zou
- Department of Pathology, Case Western Reserve University, 2103 Cornell Rd, Cleveland, OH 44106, USA;
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182
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Auffret M, Meuric V, Boyer E, Bonnaure-Mallet M, Vérin M. Oral Health Disorders in Parkinson's Disease: More than Meets the Eye. JOURNAL OF PARKINSONS DISEASE 2021; 11:1507-1535. [PMID: 34250950 PMCID: PMC8609694 DOI: 10.3233/jpd-212605] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite clinical evidence of poor oral health and hygiene in Parkinson’s disease (PD) patients, the mouth is often overlooked by both patients and the medical community, who generally focus on motor or psychiatric disorders considered more burdensome. Yet, oral health is in a two-way relationship with overall health—a weakened status triggering a decline in the quality of life. Here, we aim at giving a comprehensive overview of oral health disorders in PD, while identifying their etiologies and consequences. The physical (abnormal posture, muscle tone, tremor, and dyskinesia), behavioral (cognitive and neuropsychiatric disorders), and iatrogenic patterns associated with PD have an overall detrimental effect on patients’ oral health, putting them at risk for other disorders (infections, aspiration, pain, malnutrition), reducing their quality of life and increasing their isolation (anxiety, depression, communication issues). Interdisciplinary cooperation for prevention, management and follow-up strategies need to be implemented at an early stage to maintain and improve patients’ overall comfort and condition. Recommendations for practice, including (non-)pharmacological management strategies are discussed, with an emphasis on the neurologists’ role. Of interest, the oral cavity may become a valuable tool for diagnosis and prognosis in the near future (biomarkers). This overlooked but critical issue requires further attention and interdisciplinary research.
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Affiliation(s)
- Manon Auffret
- Behavior & Basal Ganglia Research Unit (EA 4712), University of Rennes 1, Rennes, France.,Institut des Neurosciences Cliniques de Rennes (INCR), Rennes, France
| | - Vincent Meuric
- INSERM, INRAE, Université de Rennes 1, CHU de Rennes, Nutrition Metabolisms and Cancer, Rennes, France
| | - Emile Boyer
- INSERM, INRAE, Université de Rennes 1, CHU de Rennes, Nutrition Metabolisms and Cancer, Rennes, France
| | - Martine Bonnaure-Mallet
- INSERM, INRAE, Université de Rennes 1, CHU de Rennes, Nutrition Metabolisms and Cancer, Rennes, France
| | - Marc Vérin
- Behavior & Basal Ganglia Research Unit (EA 4712), University of Rennes 1, Rennes, France.,Institut des Neurosciences Cliniques de Rennes (INCR), Rennes, France.,Movement Disorders Unit, Neurology Department, Pontchaillou University Hospital, Rennes, France
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183
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Singh A, Dawson TM, Kulkarni S. Neurodegenerative disorders and gut-brain interactions. J Clin Invest 2021; 131:e143775. [PMID: 34196307 DOI: 10.1172/jci143775] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative disorders (NDs) affect essential functions not only in the CNS, but also cause persistent gut dysfunctions, suggesting that they have an impact on both CNS and gut-innervating neurons. Although the CNS biology of NDs continues to be well studied, how gut-innervating neurons, including those that connect the gut to the brain, are affected by or involved in the etiology of these debilitating and progressive disorders has been understudied. Studies in recent years have shown how CNS and gut biology, aided by the gut-brain connecting neurons, modulate each other's functions. These studies underscore the importance of exploring the gut-innervating and gut-brain connecting neurons of the CNS and gut function in health, as well as the etiology and progression of dysfunction in NDs. In this Review, we discuss our current understanding of how the various gut-innervating neurons and gut physiology are involved in the etiology of NDs, including Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis, to cause progressive CNS and persistent gut dysfunction.
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Affiliation(s)
- Alpana Singh
- Center for Neurogastroenterology, Division of Gastroenterology and Hepatology, Department of Medicine
| | - Ted M Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering.,Department of Neurology.,Solomon H. Snyder Department of Neuroscience, and.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana, USA
| | - Subhash Kulkarni
- Center for Neurogastroenterology, Division of Gastroenterology and Hepatology, Department of Medicine
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184
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Ferreira N, Gram H, Sorrentino ZA, Gregersen E, Schmidt SI, Reimer L, Betzer C, Perez-Gozalbo C, Beltoja M, Nagaraj M, Wang J, Nowak JS, Dong M, Willén K, Cholak E, Bjerregaard-Andersen K, Mendez N, Rabadia P, Shahnawaz M, Soto C, Otzen DE, Akbey Ü, Meyer M, Giasson BI, Romero-Ramos M, Jensen PH. Multiple system atrophy-associated oligodendroglial protein p25α stimulates formation of novel α-synuclein strain with enhanced neurodegenerative potential. Acta Neuropathol 2021; 142:87-115. [PMID: 33978813 PMCID: PMC8217051 DOI: 10.1007/s00401-021-02316-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 01/08/2023]
Abstract
Pathology consisting of intracellular aggregates of alpha-Synuclein (α-Syn) spread through the nervous system in a variety of neurodegenerative disorders including Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. The discovery of structurally distinct α-Syn polymorphs, so-called strains, supports a hypothesis where strain-specific structures are templated into aggregates formed by native α-Syn. These distinct strains are hypothesised to dictate the spreading of pathology in the tissue and the cellular impact of the aggregates, thereby contributing to the variety of clinical phenotypes. Here, we present evidence of a novel α-Syn strain induced by the multiple system atrophy-associated oligodendroglial protein p25α. Using an array of biophysical, biochemical, cellular, and in vivo analyses, we demonstrate that compared to α-Syn alone, a substoichiometric concentration of p25α redirects α-Syn aggregation into a unique α-Syn/p25α strain with a different structure and enhanced in vivo prodegenerative properties. The α-Syn/p25α strain induced larger inclusions in human dopaminergic neurons. In vivo, intramuscular injection of preformed fibrils (PFF) of the α-Syn/p25α strain compared to α-Syn PFF resulted in a shortened life span and a distinct anatomical distribution of inclusion pathology in the brain of a human A53T transgenic (line M83) mouse. Investigation of α-Syn aggregates in brain stem extracts of end-stage mice demonstrated that the more aggressive phenotype of the α-Syn/p25α strain was associated with an increased load of α-Syn aggregates based on a Förster resonance energy transfer immunoassay and a reduced α-Syn aggregate seeding activity based on a protein misfolding cyclic amplification assay. When injected unilaterally into the striata of wild-type mice, the α-Syn/p25α strain resulted in a more-pronounced motoric phenotype than α-Syn PFF and exhibited a "tropism" for nigro-striatal neurons compared to α-Syn PFF. Overall, our data support a hypothesis whereby oligodendroglial p25α is responsible for generating a highly prodegenerative α-Syn strain in multiple system atrophy.
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185
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Dumitrescu L, Marta D, Dănău A, Lefter A, Tulbă D, Cozma L, Manole E, Gherghiceanu M, Ceafalan LC, Popescu BO. Serum and Fecal Markers of Intestinal Inflammation and Intestinal Barrier Permeability Are Elevated in Parkinson's Disease. Front Neurosci 2021; 15:689723. [PMID: 34220443 PMCID: PMC8249847 DOI: 10.3389/fnins.2021.689723] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/26/2021] [Indexed: 11/13/2022] Open
Abstract
Parkinson's disease (PD) is characterized by alpha-synuclein misfolding with subsequent intraneuronal amyloid formation and accumulation, low grade neuroinflammatory changes, and selective neurodegeneration. Available evidence suggests that the pathology usually begins in the gut and olfactory mucosa, spreading to the brain via the vagus and olfactory nerves, by a prion-like mechanism. A causal relationship has not been established, but gut dysbiosis is prevalent in PD and may lead to intestinal inflammation and barrier dysfunction. Additionally, epidemiological data indicate a link between inflammatory bowel diseases and PD. Calprotectin and zonulin are markers of intestinal inflammation and barrier permeability, respectively. We evaluated their serum and fecal levels in 22 patients with sporadic PD and 16 unmatched healthy controls. Mean calprotectin was higher in PD, both in serum (14.26 mcg/ml ± 4.50 vs. 5.94 mcg/ml ± 3.80, p = 0.0125) and stool (164.54 mcg/g ± 54.19 vs. 56.19 mcg/g ± 35.88, p = 0.0048). Mean zonulin was also higher in PD serum (26.69 ng/ml ± 3.55 vs. 19.43 ng/ml ± 2.56, p = 0.0046) and stool (100.19 ng/ml ± 28.25 vs. 37.3 ng/ml ± 13.26, p = 0.0012). Calprotectin was above the upper reference limit in 19 PD serums and 6 controls (OR = 10.56, 95% CI = 2.17-51.42, p = 0.0025) and in 20 PD stool samples and 4 controls (OR = 30, 95% CI = 4.75-189.30, p = 0.000045). Increased zonulin was found only in the stool samples of 8 PD patients. Despite the small sample size, our findings are robust, complementing and supporting other recently published results. The relation between serum and fecal calprotectin and zonulin levels and sporadic PD warrants further investigation in larger cohorts.
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Affiliation(s)
- Laura Dumitrescu
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania
| | - Daciana Marta
- Laboratory of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeş", National Institute of Pathology, Bucharest, Romania
| | - Adela Dănău
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania
| | - Antonia Lefter
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania
| | - Delia Tulbă
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania
| | - Liviu Cozma
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania
| | - Emilia Manole
- Laboratory of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeş", National Institute of Pathology, Bucharest, Romania.,Pathology Department, Colentina Clinical Hospital, Bucharest, Romania
| | - Mihaela Gherghiceanu
- Laboratory of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeş", National Institute of Pathology, Bucharest, Romania.,Department of Cellular and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Laura Cristina Ceafalan
- Laboratory of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeş", National Institute of Pathology, Bucharest, Romania.,Department of Cellular and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Bogdan Ovidiu Popescu
- Department of Clinical Neurosciences, Neurology Division at Colentina Clinical Hospital, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.,Department of Neurology, Colentina Clinical Hospital, Bucharest, Romania.,Laboratory of Cell Biology, Neurosciences and Experimental Myology, "Victor Babeş", National Institute of Pathology, Bucharest, Romania
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186
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Long LL, Svenson KL, Mourino AJ, Michaud M, Fahey JR, Waterman L, Vandegrift KL, Adams MD. Shared and distinctive features of the gut microbiome of C57BL/6 mice from different vendors and production sites, and in response to a new vivarium. Lab Anim (NY) 2021; 50:185-195. [PMID: 34127866 DOI: 10.1038/s41684-021-00777-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 05/07/2021] [Indexed: 02/08/2023]
Abstract
Animal models play a critical role in establishing causal relationships between gut microbiota and disease. The laboratory mouse is widely used to study the role of microbes in various disorders; however, differences between mouse vendors, genetic lineages and husbandry protocols have been shown to contribute to variation in phenotypes and to non-reproducibility of experimental results. We sought to understand how gut microbiome profiles of mice vary by vendor, vendor production facility and health status upon receipt into an academic facility and how they change over 12 weeks in the new environment. C57BL/6 mice were sourced from two different production sites for each of three different vendors. Mice were shipped to an academic research vivarium, and fresh-catch stool samples were collected from mice immediately from the shipping box upon receipt, and again after 2, 6 and 12 weeks in the new facility. Substantial variation in bacterial proportional abundance was observed among mice from each vendor at the time of receipt, but shared microbes accounted for most sequence reads. Vendor-specific microbes were generally of low abundance. Microbial profiles of mice from all vendors exhibited shifts over time, highlighting the importance of environmental conditions on microbial dynamics. Our results emphasize the need for continued efforts to account for sources of variation in animal models and understand how they contribute to experimental reproducibility.
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Affiliation(s)
- Lauren L Long
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Karen L Svenson
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | | | - Michael Michaud
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - James R Fahey
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, USA
| | - Linda Waterman
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | | | - Mark D Adams
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
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187
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Christensen LFB, Alijanvand SH, Burdukiewicz M, Herbst FA, Kjeldal H, Dueholm MS, Otzen DE. Identification of amyloidogenic proteins in the microbiomes of a rat Parkinson's disease model and wild-type rats. Protein Sci 2021; 30:1854-1870. [PMID: 34075639 DOI: 10.1002/pro.4137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/18/2022]
Abstract
Cross seeding between amyloidogenic proteins in the gut is receiving increasing attention as a possible mechanism for initiation or acceleration of amyloid formation by aggregation-prone proteins such as αSN, which is central in the development of Parkinson's disease (PD). This is particularly pertinent in view of the growing number of functional (i.e., benign and useful) amyloid proteins discovered in bacteria. Here we identify two amyloidogenic proteins, Pr12 and Pr17, in fecal matter from PD transgenic rats and their wild type counterparts, based on their stability against dissolution by formic acid (FA). Both proteins show robust aggregation into ThT-positive aggregates that contain higher-order β-sheets and have a fibrillar morphology, indicative of amyloid proteins. In addition, Pr17 aggregates formed in vitro showed significant resistance against FA, suggesting an ability to form highly stable amyloid. Treatment with proteinase K revealed a protected core of approx. 9 kDa. Neither Pr12 nor Pr17, however, affected αSN aggregation in vitro. Thus, amyloidogenicity does not per se lead to an ability to cross-seed fibrillation of αSN. Our results support the use of proteomics and FA to identify amyloidogenic protein in complex mixtures and suggests that there may be numerous functional amyloid proteins in microbiomes.
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Affiliation(s)
- Line Friis Bakmann Christensen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Saeid Hadi Alijanvand
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.,Institute of Biochemistry and Biophysics (IBB), Department of Biophysics, University of Tehran, Tehran, Iran
| | - Michał Burdukiewicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Centre for Clinical Research, Medical University of Białystok, Białystok, Poland
| | - Florian-Alexander Herbst
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Henrik Kjeldal
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Morten Simonsen Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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188
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Gómez-Pérez D, Chaudhry V, Kemen A, Kemen E. Amyloid Proteins in Plant-Associated Microbial Communities. Microb Physiol 2021; 31:88-98. [PMID: 34107493 DOI: 10.1159/000516014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/17/2021] [Indexed: 11/19/2022]
Abstract
Amyloids have proven to be a widespread phenomenon rather than an exception. Many proteins presenting the hallmarks of this characteristic beta sheet-rich folding have been described to date. Particularly common are functional amyloids that play an important role in the promotion of survival and pathogenicity in prokaryotes. Here, we describe important developments in amyloid protein research that relate to microbe-microbe and microbe-host interactions in the plant microbiome. Starting with biofilms, which are a broad strategy for bacterial persistence that is extremely important for plant colonization. Microbes rely on amyloid-based mechanisms to adhere and create a protective coating that shelters them from external stresses and promotes cooperation. Another strategy generally carried out by amyloids is the formation of hydrophobic surface layers. Known as hydrophobins, these proteins coat the aerial hyphae and spores of plant pathogenic fungi, as well as certain bacterial biofilms. They contribute to plant virulence through promoting dissemination and infectivity. Furthermore, antimicrobial activity is an interesting outcome of the amyloid structure that has potential application in medicine and agriculture. There are many known antimicrobial amyloids released by animals and plants; however, those produced by bacteria or fungi remain still largely unknown. Finally, we discuss amyloid proteins with a more indirect mode of action in their host interactions. These include virulence-promoting harpins, signaling transduction that functions through amyloid templating, and root nodule bacteria proteins that promote plant-microbe symbiosis. In summary, amyloids are an interesting paradigm for their many functional mechanisms linked to bacterial survival in plant-associated microbial communities.
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Affiliation(s)
| | | | - Ariane Kemen
- ZMBP/IMIT, University of Tübingen, Tübingen, Germany
| | - Eric Kemen
- ZMBP/IMIT, University of Tübingen, Tübingen, Germany
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189
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Zhao H. The human microbiome and genetic disease: towards the integration of metagenomic and multi-omics data. Hum Genet 2021; 140:701-702. [PMID: 33783596 DOI: 10.1007/s00439-021-02277-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Huiying Zhao
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
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190
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Abstract
Neurodegenerative disorders are frequently associated with β-sheet-rich amyloid deposits. Amyloid-forming proteins can aggregate under different structural conformations known as strains, which can exhibit a prion-like behavior and distinct pathophenotypes. Precise molecular determinants defining strain specificity and cross-strain interactions (cross-seeding) are currently unknown. The HET-s prion protein from the fungus Podospora anserina represents a model system to study the fundamental properties of prion amyloids. Here, we report the amyloid prion structure of HELLF, a distant homolog of the model prion HET-s. We find that these two amyloids, sharing only 17% sequence identity, have nearly identical β-solenoid folds but lack cross-seeding ability in vivo, indicating that prion specificity can differ in extremely similar amyloid folds. We engineer the HELLF sequence to explore the limits of the sequence-to-fold conservation and to pinpoint determinants of cross-seeding and prion specificity. We find that amyloid fold conservation occurs even at an exceedingly low level of identity to HET-s (5%). Next, we derive a HELLF-based sequence, termed HEC, able to breach the cross-seeding barrier in vivo between HELLF and HET-s, unveiling determinants controlling cross-seeding at residue level. These findings show that virtually identical amyloid backbone structures might not be sufficient for cross-seeding and that critical side-chain positions could determine the seeding specificity of an amyloid fold. Our work redefines the conceptual boundaries of prion strain and sheds light on key molecular features concerning an important class of pathogenic agents.
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191
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Szulc N, Gąsior-Głogowska M, Wojciechowski JW, Szefczyk M, Żak AM, Burdukiewicz M, Kotulska M. Variability of Amyloid Propensity in Imperfect Repeats of CsgA Protein of Salmonella enterica and Escherichia coli. Int J Mol Sci 2021; 22:ijms22105127. [PMID: 34066237 PMCID: PMC8151669 DOI: 10.3390/ijms22105127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 04/22/2021] [Accepted: 05/07/2021] [Indexed: 11/18/2022] Open
Abstract
CsgA is an aggregating protein from bacterial biofilms, representing a class of functional amyloids. Its amyloid propensity is defined by five fragments (R1–R5) of the sequence, representing non-perfect repeats. Gate-keeper amino acid residues, specific to each fragment, define the fragment’s propensity for self-aggregation and aggregating characteristics of the whole protein. We study the self-aggregation and secondary structures of the repeat fragments of Salmonella enterica and Escherichia coli and comparatively analyze their potential effects on these proteins in a bacterial biofilm. Using bioinformatics predictors, ATR-FTIR and FT-Raman spectroscopy techniques, circular dichroism, and transmission electron microscopy, we confirmed self-aggregation of R1, R3, R5 fragments, as previously reported for Escherichia coli, however, with different temporal characteristics for each species. We also observed aggregation propensities of R4 fragment of Salmonella enterica that is different than that of Escherichia coli. Our studies showed that amyloid structures of CsgA repeats are more easily formed and more durable in Salmonella enterica than those in Escherichia coli.
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Affiliation(s)
- Natalia Szulc
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (N.S.); (M.G.-G.); (J.W.W.)
- LPCT, CNRS, Université de Lorraine, F-54000 Nancy, France
| | - Marlena Gąsior-Głogowska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (N.S.); (M.G.-G.); (J.W.W.)
| | - Jakub W. Wojciechowski
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (N.S.); (M.G.-G.); (J.W.W.)
| | - Monika Szefczyk
- Department of Bioorganic Chemistry, Faculty of Chemistry, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland;
| | - Andrzej M. Żak
- Electron Microscopy Laboratory, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland;
| | - Michał Burdukiewicz
- Clinical Research Centre, Medical University of Białystok, Jana Kilińskiego 1, 15-089 Białystok, Poland
- Institute of Biochemistry and Biophysics, Polish Academy Sciences, 02-106 Warsaw, Poland
- Faculty of Natural Sciences, Brandenburg University of Technology Cottbus-Senftenberg, 01968 Senftenberg, Germany
- Correspondence: (M.B.); (M.K.)
| | - Malgorzata Kotulska
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (N.S.); (M.G.-G.); (J.W.W.)
- Correspondence: (M.B.); (M.K.)
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192
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Vojdani A, Lerner A, Vojdani E. Cross-Reactivity and Sequence Homology Between Alpha-Synuclein and Food Products: A Step Further for Parkinson's Disease Synucleinopathy. Cells 2021; 10:cells10051111. [PMID: 34063062 PMCID: PMC8147930 DOI: 10.3390/cells10051111] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/24/2021] [Accepted: 05/03/2021] [Indexed: 12/19/2022] Open
Abstract
INTRODUCTION Parkinson's disease is characterized by non-motor/motor dysfunction midbrain neuronal death and α-synuclein deposits. The accepted hypothesis is that unknown environmental factors induce α-synuclein accumulation in the brain via the enteric nervous system. MATERIAL AND METHODS Monoclonal antibodies made against recombinant α-synuclein protein or α-synuclein epitope 118-123 were applied to the antigens of 180 frequently consumed food products. The specificity of those antibody-antigen reactions was confirmed by serial dilution and inhibition studies. The Basic Local Alignment Search Tool sequence matching program was used for sequence homologies. RESULTS While the antibody made against recombinant α-synuclein reacted significantly with 86/180 specific food antigens, the antibody made against α-synuclein epitope 118-123 reacted with only 32/180 tested food antigens. The food proteins with the greatest number of peptides that matched with α-synuclein were yeast, soybean, latex hevein, wheat germ agglutinin, potato, peanut, bean agglutinin, pea lectin, shrimp, bromelain, and lentil lectin. Conclusions: The cross-reactivity and sequence homology between α-synuclein and frequently consumed foods, reinforces the autoimmune aspect of Parkinson's disease. It is hypothesized that luminal food peptides that share cross-reactive epitopes with human α-synuclein and have molecular similarity with brain antigens are involved in the synucleinopathy. The findings deserve further confirmation by extensive research.
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Affiliation(s)
- Aristo Vojdani
- Immunosciences Laboratory, Inc., Los Angeles, CA 90035, USA;
- Cyrex Laboratories, Phoenix, AZ 85034, USA
- Department of Preventive Medicine, Loma Linda University School of Medicine, Loma Linda, CA 92354, USA
| | - Aaron Lerner
- Chaim Sheba Medical Center, Zabludowicz Center for Autoimmune Diseases, Tel-Hashomer 52621, Israel
- Correspondence: ; Tel.: +97-25-2591-9484
| | - Elroy Vojdani
- Regenera Medical,11620 Wilshire Blvd., Ste. 470, Los Angeles, CA 90025, USA;
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Lerner A. The intestinal luminal sources of α-synuclein: a gastroenterologist perspective. Nutr Rev 2021; 80:282-293. [PMID: 33942062 DOI: 10.1093/nutrit/nuab024] [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] [Indexed: 12/12/2022] Open
Abstract
Parkinson's disease is characterized by nonmotor/motor dysfunction, midbrain dopaminergic neuronal death, and α-synuclein (aSN) deposits. The current hypothesis is that aSN accumulates in the enteric nervous system to reach the brain. However, invertebrate, vertebrate, and nutritional sources of aSN reach the luminal compartment. Submitted to local amyloidogenic forces, the oligomerized proteins' cargo can be sensed and sampled by a specialized mucosal cell to be transmitted to the adjacent enteric nervous system, starting their upward journey to the brain. The present narrative review extends the current mucosal origin of Parkinson's disease, presenting the possibility that the disease starts in the intestinal lumen. If substantiated, eliminating the nutritional sources of aSN (eg, applying a vegetarian diet) might revolutionize the currently used dopaminergic pharmacologic therapy.
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Affiliation(s)
- Aaron Lerner
- A. Lerner is with the Zabludowicz Center for Autoimmune Diseases, Chaim Sheba Medical Center, Tel-Hashomer, Israel
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194
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Walker AC, Bhargava R, Vaziriyan-Sani AS, Pourciau C, Donahue ET, Dove AS, Gebhardt MJ, Ellward GL, Romeo T, Czyż DM. Colonization of the Caenorhabditis elegans gut with human enteric bacterial pathogens leads to proteostasis disruption that is rescued by butyrate. PLoS Pathog 2021; 17:e1009510. [PMID: 33956916 PMCID: PMC8101752 DOI: 10.1371/journal.ppat.1009510] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
Protein conformational diseases are characterized by misfolding and toxic aggregation of metastable proteins, often culminating in neurodegeneration. Enteric bacteria influence the pathogenesis of neurodegenerative diseases; however, the complexity of the human microbiome hinders our understanding of how individual microbes influence these diseases. Disruption of host protein homeostasis, or proteostasis, affects the onset and progression of these diseases. To investigate the effect of bacteria on host proteostasis, we used Caenorhabditis elegans expressing tissue-specific polyglutamine reporters that detect changes in the protein folding environment. We found that colonization of the C. elegans gut with enteric bacterial pathogens disrupted proteostasis in the intestine, muscle, neurons, and the gonad, while the presence of bacteria that conditionally synthesize butyrate, a molecule previously shown to be beneficial in neurodegenerative disease models, suppressed aggregation and the associated proteotoxicity. Co-colonization with this butyrogenic strain suppressed bacteria-induced protein aggregation, emphasizing the importance of microbial interaction and its impact on host proteostasis. Further experiments demonstrated that the beneficial effect of butyrate depended on the bacteria that colonized the gut and that this protective effect required SKN-1/Nrf2 and DAF-16/FOXO transcription factors. We also found that bacteria-derived protein aggregates contribute to the observed disruption of host proteostasis. Together, these results reveal the significance of enteric infection and gut dysbiosis on the pathogenesis of protein conformational diseases and demonstrate the potential of using butyrate-producing microbes as a preventative and treatment strategy for neurodegenerative disease.
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Affiliation(s)
- Alyssa C. Walker
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Rohan Bhargava
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Alfonso S. Vaziriyan-Sani
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Christine Pourciau
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Emily T. Donahue
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Autumn S. Dove
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Michael J. Gebhardt
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Garrett L. Ellward
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Tony Romeo
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Daniel M. Czyż
- Department of Microbiology & Cell Science, University of Florida, Gainesville, Florida, United States of America
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195
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Khambhati K, Patel J, Saxena V, A P, Jain N. Gene Regulation of Biofilm-Associated Functional Amyloids. Pathogens 2021; 10:490. [PMID: 33921583 PMCID: PMC8072697 DOI: 10.3390/pathogens10040490] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 01/01/2023] Open
Abstract
Biofilms are bacterial communities encased in a rigid yet dynamic extracellular matrix. The sociobiology of bacterial communities within a biofilm is astonishing, with environmental factors playing a crucial role in determining the switch from planktonic to a sessile form of life. The mechanism of biofilm biogenesis is an intriguingly complex phenomenon governed by the tight regulation of expression of various biofilm-matrix components. One of the major constituents of the biofilm matrix is proteinaceous polymers called amyloids. Since the discovery, the significance of biofilm-associated amyloids in adhesion, aggregation, protection, and infection development has been much appreciated. The amyloid expression and assembly is regulated spatio-temporarily within the bacterial cells to perform a diverse function. This review provides a comprehensive account of the genetic regulation associated with the expression of amyloids in bacteria. The stringent control ensures optimal utilization of amyloid scaffold during biofilm biogenesis. We conclude the review by summarizing environmental factors influencing the expression and regulation of amyloids.
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Affiliation(s)
- Khushal Khambhati
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur NH 65, Nagaur Road, Karwar, Rajasthan 342037, India
| | - Jaykumar Patel
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur NH 65, Nagaur Road, Karwar, Rajasthan 342037, India
| | - Vijaylaxmi Saxena
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur NH 65, Nagaur Road, Karwar, Rajasthan 342037, India
| | - Parvathy A
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur NH 65, Nagaur Road, Karwar, Rajasthan 342037, India
| | - Neha Jain
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur NH 65, Nagaur Road, Karwar, Rajasthan 342037, India
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196
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Wang Q, Luo Y, Chaudhuri KR, Reynolds R, Tan EK, Pettersson S. The role of gut dysbiosis in Parkinson's disease: mechanistic insights andtherapeutic options. Brain 2021; 144:2571-2593. [PMID: 33856024 DOI: 10.1093/brain/awab156] [Citation(s) in RCA: 121] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/23/2021] [Accepted: 03/23/2021] [Indexed: 12/02/2022] Open
Abstract
Parkinson's disease is a common neurodegenerative disease in which gastrointestinal symptoms may appear prior to motor symptoms. The gut microbiota of patients with Parkinson's disease shows unique changes, which may be used as early biomarkers of disease. Alteration in gut microbiota composition may be related to the cause or effect of motor or non-motor symptoms, but the specific pathogenic mechanisms are unclear. The gut microbiota and its metabolites have been suggested to be involved in the pathogenesis of Parkinson's disease by regulating neuroinflammation, barrier function and neurotransmitter activity. There is bidirectional communication between the enteric nervous system and the central nervous system, and the microbiota-gut-brain axis may provide a pathway for the transmission of α-synuclein. We highlight recent discoveries and alterations of the gut microbiota in Parkinson's disease, and highlight current mechanistic insights on the microbiota-gut-brain axis in disease pathophysiology. We discuss the interactions between production and transmission of α-synuclein and gut inflammation and neuroinflammation. In addition, we also draw attention to diet modification, use of probiotics and prebiotics and fecal microbiota transplantation as potential therapeutic approaches that may lead to a new treatment paradigm for Parkinson's disease.
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Affiliation(s)
- Qing Wang
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, China
| | - Yuqi Luo
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong 510282, China
| | - K Ray Chaudhuri
- Parkinson Foundation International Centre of Excellence at King's College Hospital, and Kings College, Denmark Hill, London, SE5 9RS, UK
| | - Richard Reynolds
- Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, Du Cane Road, London, W12 0NN, UK.,Centre for Molecular Neuropathology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore.,Duke-NUS Medical School, Singapore
| | - Sven Pettersson
- Department of Neurology, National Neuroscience Institute, Singapore General Hospital, Singapore.,Duke-NUS Medical School, Singapore.,LKC School of Medicine, NTU, Singapore.,Sunway University, Department of Medical Sciences, Kuala Lumpur, Malaysia
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197
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Edskes HK, Stroobant EE, DeWilde MP, Bezsonov EE, Wickner RB. Proteasome Control of [URE3] Prion Propagation by Degradation of Anti-Prion Proteins Cur1 and Btn2 in Saccharomyces cerevisiae. Genetics 2021; 218:6179111. [PMID: 33742650 DOI: 10.1093/genetics/iyab037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/27/2021] [Indexed: 01/16/2023] Open
Abstract
[URE3] is a prion of the nitrogen catabolism controller, Ure2p, and [PSI+] is a prion of the translation termination factor Sup35p in S. cerevisiae. Btn2p cures [URE3] by sequestration of Ure2p amyloid filaments. Cur1p, paralogous to Btn2p, also cures [URE3], but by a different (unknown) mechanism. We find that an array of mutations impairing proteasome assembly or MG132 inhibition of proteasome activity result in loss of [URE3]. In proportion to their prion-curing effects, each mutation affecting proteasomes elevates the cellular concentration of the anti-prion proteins Btn2 and Cur1. Of >4,600 proteins detected by SILAC, Btn2p was easily the most overexpressed in a pre9Δ (α3 core subunit) strain. Indeed, deletion of BTN2 and CUR1 prevents the prion-curing effects of proteasome impairment. Surprisingly, the 15 most unstable yeast proteins are not increased in pre9Δ cells suggesting altered proteasome specificity rather than simple inactivation. Hsp42, a chaperone that cooperates with Btn2 and Cur1 in curing [URE3], is also necessary for the curing produced by proteasome defects, although Hsp42p levels are not substantially altered by a proteasome defect. We find that pre9Δ and proteasome chaperone mutants that most efficiently lose [URE3], do not destabilize [PSI+] or alter cellular levels of Sup35p. A tof2 mutation or deletion likewise destabilizes [URE3], and elevates Btn2p, suggesting that Tof2p deficiency inactivates proteasomes. We suggest that when proteasomes are saturated with denatured/misfolded proteins, their reduced degradation of Btn2p and Cur1p automatically upregulates these aggregate-handling systems to assist in the clean-up.
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Affiliation(s)
- Herman K Edskes
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Emily E Stroobant
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Morgan P DeWilde
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Evgeny E Bezsonov
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
| | - Reed B Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA
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198
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Ojeda J, Ávila A, Vidal PM. Gut Microbiota Interaction with the Central Nervous System throughout Life. J Clin Med 2021; 10:1299. [PMID: 33801153 PMCID: PMC8004117 DOI: 10.3390/jcm10061299] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 02/08/2023] Open
Abstract
During the last years, accumulating evidence has suggested that the gut microbiota plays a key role in the pathogenesis of neurodevelopmental and neurodegenerative diseases via the gut-brain axis. Moreover, current research has helped to elucidate different communication pathways between the gut microbiota and neural tissues (e.g., the vagus nerve, tryptophan production, extrinsic enteric-associated neurons, and short chain fatty acids). On the other hand, altering the composition of gut microbiota promotes a state known as dysbiosis, where the balance between helpful and pathogenic bacteria is disrupted, usually stimulating the last ones. Herein, we summarize selected findings of the recent literature concerning the gut microbiome on the onset and progression of neurodevelopmental and degenerative disorders, and the strategies to modulate its composition in the search for therapeutical approaches, focusing mainly on animal models studies. Readers are advised that this is a young field, based on early studies, that is rapidly growing and being updated as the field advances.
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Affiliation(s)
- Jorge Ojeda
- Neuroimmunology and Regeneration of the Central Nervous System Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile;
| | - Ariel Ávila
- Developmental Neurobiology Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile;
| | - Pía M. Vidal
- Neuroimmunology and Regeneration of the Central Nervous System Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción 4090541, Chile;
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200
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Lee JG, Cho HJ, Jeong YM, Lee JS. Genetic Approaches Using Zebrafish to Study the Microbiota-Gut-Brain Axis in Neurological Disorders. Cells 2021; 10:cells10030566. [PMID: 33807650 PMCID: PMC8002147 DOI: 10.3390/cells10030566] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/26/2021] [Accepted: 02/28/2021] [Indexed: 12/12/2022] Open
Abstract
The microbiota-gut-brain axis (MGBA) is a bidirectional signaling pathway mediating the interaction of the microbiota, the intestine, and the central nervous system. While the MGBA plays a pivotal role in normal development and physiology of the nervous and gastrointestinal system of the host, its dysfunction has been strongly implicated in neurological disorders, where intestinal dysbiosis and derived metabolites cause barrier permeability defects and elicit local inflammation of the gastrointestinal tract, concomitant with increased pro-inflammatory cytokines, mobilization and infiltration of immune cells into the brain, and the dysregulated activation of the vagus nerve, culminating in neuroinflammation and neuronal dysfunction of the brain and behavioral abnormalities. In this topical review, we summarize recent findings in human and animal models regarding the roles of the MGBA in physiological and neuropathological conditions, and discuss the molecular, genetic, and neurobehavioral characteristics of zebrafish as an animal model to study the MGBA. The exploitation of zebrafish as an amenable genetic model combined with in vivo imaging capabilities and gnotobiotic approaches at the whole organism level may reveal novel mechanistic insights into microbiota-gut-brain interactions, especially in the context of neurological disorders such as autism spectrum disorder and Alzheimer's disease.
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Affiliation(s)
- Jae-Geun Lee
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (J.-G.L.); (H.-J.C.); (Y.-M.J.)
- KRIBB School, University of Science and Technology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
| | - Hyun-Ju Cho
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (J.-G.L.); (H.-J.C.); (Y.-M.J.)
| | - Yun-Mi Jeong
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (J.-G.L.); (H.-J.C.); (Y.-M.J.)
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
| | - Jeong-Soo Lee
- Disease Target Structure Research Center, KRIBB, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea; (J.-G.L.); (H.-J.C.); (Y.-M.J.)
- KRIBB School, University of Science and Technology, 125 Gwahak-ro, Yuseong-gu, Daejeon 34141, Korea
- Dementia DTC R&D Convergence Program, KIST, Hwarang-ro 14 gil 5, Seongbuk-gu, Seoul 02792, Korea
- Correspondence: ; Tel.: +82-42-860-4643
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