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Pellegrini C, Travagli RA. Gastrointestinal dysmotility in rodent models of Parkinson's disease. Am J Physiol Gastrointest Liver Physiol 2024; 326:G345-G359. [PMID: 38261717 PMCID: PMC11212145 DOI: 10.1152/ajpgi.00225.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/09/2024] [Accepted: 01/22/2024] [Indexed: 01/25/2024]
Abstract
Multiple studies describe prodromal, nonmotor dysfunctions that affect the quality of life of patients who subsequently develop Parkinson's disease (PD). These prodromal dysfunctions comprise a wide array of autonomic issues, including severe gastrointestinal (GI) motility disorders such as dysphagia, delayed gastric emptying, and chronic constipation. Indeed, strong evidence from studies in humans and animal models suggests that the GI tract and its neural, mainly vagal, connection to the central nervous system (CNS) could have a major role in the etiology of PD. In fact, misfolded α-synuclein aggregates that form Lewy bodies and neurites, i.e., the histological hallmarks of PD, are detected in the enteric nervous system (ENS) before clinical diagnosis of PD. The aim of the present review is to provide novel insights into the pathogenesis of GI dysmotility in PD, focusing our attention on functional, neurochemical, and molecular alterations in animal models.
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Affiliation(s)
- Carolina Pellegrini
- Unit of Histology and Medical Embryology, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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2
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Sawamura T, Yuki N, Aoki K, Horii K, Horii Y, Naitou K, Tsukamoto S, Shiina T, Shimizu Y. Alterations in descending brain-spinal pathways regulating colorectal motility in a rat model of Parkinson's disease. Am J Physiol Gastrointest Liver Physiol 2024; 326:G195-G204. [PMID: 38111988 DOI: 10.1152/ajpgi.00181.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/13/2023] [Accepted: 12/17/2023] [Indexed: 12/20/2023]
Abstract
Patients with Parkinson's disease (PD) often have constipation. It is assumed that a disorder of the regulatory mechanism of colorectal motility by the central nervous system is involved in the constipation, but this remains unclear. The aim of this study was to investigate whether central neural pathways can modulate colorectal motility in a rat model of PD. PD model rats were generated by injection of 6-hydroxydopamine into a unilateral medial forebrain bundle and destruction of dopaminergic neurons in the substantia nigra. Colorectal motility was measured in vivo in anesthetized rats. Intraluminal administration of capsaicin, as a noxious stimulus, induced colorectal motility in sham-operated rats but not in PD rats. Intrathecally administered dopamine (DA) and serotonin (5-HT), which mediate the prokinetic effect of capsaicin, at the L6-S1 levels enhanced colorectal motility in PD rats similarly to that in sham-operated rats. In PD rats, capsaicin enhanced colorectal motility only when a GABAA receptor antagonist was preadministered into the lumbosacral spinal cord. Capsaicin-induced colorectal motility was abolished by intrathecal administration of a D2-like receptor antagonist but not by administration of 5-HT2 and 5-HT3 receptor antagonists. These findings demonstrate that the inhibitory GABAergic component becomes operative and the stimulatory serotonergic component is suppressed in PD rats. The alteration of the central regulatory mechanism of colorectal motility is thought to be related to the occurrence of constipation in PD patients. Our findings provide a new insight into the pathogenesis of defecation disorders observed in PD.NEW & NOTEWORTHY In a rat model of Parkinson's disease, the component of descending brain-spinal pathways that regulate colorectal motility through a mediation of the lumbosacral defecation center was altered from stimulatory serotonergic neurons to inhibitory GABAergic neurons. Our findings suggest that chronic constipation in Parkinson's disease patients may be associated with alterations in central regulatory mechanisms of colorectal motility. The plasticity in the descending pathway regulating colorectal motility may contribute to other disease-related defecation abnormalities.
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Affiliation(s)
- Tomoya Sawamura
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Natsufu Yuki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Kanae Aoki
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Kazuhiro Horii
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Division of Biological Principles, Department of Physiology, Graduate School of Medicine, Gifu University, Gifu, Japan
| | - Yuuki Horii
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu, Japan
| | - Kiyotada Naitou
- Department of Basic Veterinary Science, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Shumpei Tsukamoto
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Takahiko Shiina
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Yasutake Shimizu
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Department of Basic Veterinary Science, Laboratory of Physiology, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
- Division of Animal Medical Science, Center for One Medicine Innovative Translational Research (COMIT), Gifu University Institute for Advanced Study, Gifu, Japan
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3
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Cai W, Tian H, Sun P, Hua T, Gong J, Zhang R, Wan L, Gu G, Zhang H, Tang G, Chen Q, Zhang L. Regional homogeneity alterations in patients with functional constipation and their associations with gene expression profiles. Cereb Cortex 2024; 34:bhad403. [PMID: 37981661 DOI: 10.1093/cercor/bhad403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/24/2023] [Accepted: 09/25/2023] [Indexed: 11/21/2023] Open
Abstract
Functional constipation, a highly prevalent functional gastrointestinal disorder, often accompanies by mental and psychological disorders. Previous neuroimaging studies have demonstrated brain functional and structural alterations in patients with functional constipation. However, little is known about whether and how regional homogeneity is altered in these patients. Moreover, the potential genetic mechanisms associated with these alterations remain largely unknown. The study included 73 patients with functional constipation and 68 healthy controls, and regional homogeneity comparison was conducted to identify the abnormal spontaneous brain activities in patients with functional constipation. Using Allen Human Brain Atlas, we further investigated gene expression profiles associated with regional homogeneity alterations in functional constipation patients with partial least squares regression analysis applied. Compared with healthy controls, functional constipation patients demonstrated significantly decreased regional homogeneity in both bilateral caudate nucleus, putamen, anterior insula, thalamus and right middle cingulate cortex, supplementary motor area, and increased regional homogeneity in the bilateral orbitofrontal cortex. Genes related to synaptic signaling, central nervous system development, fatty acid metabolism, and immunity were spatially correlated with abnormal regional homogeneity patterns. Our findings showed significant regional homogeneity alterations in functional constipation patients, and the changes may be caused by complex polygenetic and poly-pathway mechanisms, which provides a new perspective on functional constipation's pathophysiology.
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Affiliation(s)
- Wangli Cai
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Hongliang Tian
- Department of Colorectal Disease, Intestinal Microenvironment Treatment Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Peiwen Sun
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Ting Hua
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Jian Gong
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Ruiling Zhang
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Lidi Wan
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Guoqing Gu
- Department of Nursing, Wuliqiao Street Community Health Service Center, Shanghai 200023, China
| | - Haiying Zhang
- Department of Radiology, Chongming Branch of Shanghai Tenth People's Hospital, Shanghai 202157, China
| | - Guangyu Tang
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Qiyi Chen
- Department of Colorectal Disease, Intestinal Microenvironment Treatment Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Lin Zhang
- Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, China
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Açar Y, Ağagündüz D, De Cicco P, Capasso R. Flavonoids: Their putative neurologic roles, epigenetic changes, and gut microbiota alterations in Parkinson's disease. Biomed Pharmacother 2023; 168:115788. [PMID: 37913731 DOI: 10.1016/j.biopha.2023.115788] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023] Open
Abstract
Parkinson's Disease (PD), a neurodegenerative disorder, is characterized by the degeneration of progressive dopaminergic (DA) neurons in the substantia nigra region of the human midbrain. Although just what causes PD remains a mystery, it is known that oxidative stress (OS) as well as mitochondrial dysfunction, neuro-inflammation, and insufficient neurotrophic support play a role in the disease's pathophysiology. Phytochemicals are a diverse small molecule group derived from plants that can be classified into numerous classes on the basis of their biological activities and chemical structure. Of these groups of phytochemicals, the most abundant, which has well-established anti-Parkinson's effects, are polyphenols. Flavonoids, including naringin and naringenin, genistein, kaempferol, anthocyanins, epigallocatechin-3-gallate, and baicalein are plant-based biologically active polyphenols, which have been shown to exhibit therapeutic potential when used as treatment for a variety of pathological illnesses, such as neurodegenerative diseases (NDs) and PD. Recently, it was reported that flavonoids have beneficial effects on PD, such as the protection of DA neurons, improvement of motor and cognitive abilities, regulation of signaling pathways, and modulation of OS and neuro-inflammation. In addition, by changing the composition of bacteria in gut microbiota, flavonoids reduce pathogenic strains and promote the growth of beneficial strains. In this context, the current paper will provide a literature review on the neurological roles that flavonoids play, as one of the most abundant phytochemical families, in PD.
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Affiliation(s)
- Yasemin Açar
- Department of Nutrition and Dietetics, Gazi University, Ankara, Turkey.
| | - Duygu Ağagündüz
- Department of Nutrition and Dietetics, Gazi University, Ankara, Turkey
| | - Paola De Cicco
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, Italy
| | - Raffaele Capasso
- Department of Agricultural Sciences, University of Naples Federico II, Portici, 80055 Naples, Italy.
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Nakamori H, Hashitani H. Neural targets of the enteric dopaminergic system in regulating motility of rat proximal colon. Pflugers Arch 2023; 475:1315-1327. [PMID: 37589734 DOI: 10.1007/s00424-023-02849-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 08/02/2023] [Accepted: 08/08/2023] [Indexed: 08/18/2023]
Abstract
In isolated segments of the rat proximal colon, the dopamine reuptake inhibitor GBR 12909 (GBR) causes a dilatation, while the D1-like receptor antagonist SCH 23390 (SCH) induces a tonic constriction, suggesting that neurally released dopamine tonically stimulates enteric inhibitory efferent neurons. Here, the targets of the enteric dopaminergic neurons were investigated. Cannulated segments of rat proximal colon were bathed in physiological salt solution and luminally perfused with 0.9% saline, while all drugs were applied to the bath. Spatio-temporal maps of colonic motility were constructed from video recordings of peristaltic contractions, and the maximum diameter was measured as an index of colonic contractility. GBR (1 μM)-induced dilatations of colonic segments were prevented by SCH (5 μM), L-nitro arginine (L-NA; 100 μM), a nitric oxide synthase inhibitor, or tetrodotoxin (0.6 μM). In contrast, constrictions induced by a higher concentration of SCH (20 μM) were unaffected by either L-NA or tetrodotoxin. The vasoactive intestinal peptide (VIP) receptor antagonist VIP10-28 (3 μM) or P2Y1 receptor antagonist MRS 2500 (1 μM) had no effect on either the GBR-induced dilatation or the SCH-induced constriction. In colonic segments that had been pretreated with 6-hydroxydopamine (100 μM, 3 h) to deplete enteric dopamine, GBR failed to increase the colonic diameter, while SCH was still capable of constricting colonic segments. Enteric dopaminergic neurons appear to project to nitrergic neurons to dilate the proximal colon by activating neuronal D1-like receptors. In addition, constitutively activated D1-like receptors expressed in cells yet to be determined may provide a tonic inhibition on colonic constrictions.
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Affiliation(s)
- Hiroyuki Nakamori
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-Cho, Mizuho-Ku, Nagoya, 467-8601, Japan.
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-Cho, Mizuho-Ku, Nagoya, 467-8601, Japan
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Ortega Moreno L, Bagues A, Martínez V, Abalo R. New Pieces for an Old Puzzle: Approaching Parkinson's Disease from Translatable Animal Models, Gut Microbiota Modulation, and Lipidomics. Nutrients 2023; 15:2775. [PMID: 37375679 DOI: 10.3390/nu15122775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/15/2023] [Accepted: 05/22/2023] [Indexed: 06/29/2023] Open
Abstract
Parkinson's disease (PD) is a severe neurodegenerative disease characterized by disabling motor alterations that are diagnosed at a relatively late stage in its development, and non-motor symptoms, including those affecting the gastrointestinal tract (mainly constipation), which start much earlier than the motor symptoms. Remarkably, current treatments only reduce motor symptoms, not without important drawbacks (relatively low efficiency and impactful side effects). Thus, new approaches are needed to halt PD progression and, possibly, to prevent its development, including new therapeutic strategies that target PD etiopathogeny and new biomarkers. Our aim was to review some of these new approaches. Although PD is complex and heterogeneous, compelling evidence suggests it might have a gastrointestinal origin, at least in a significant number of patients, and findings in recently developed animal models strongly support this hypothesis. Furthermore, the modulation of the gut microbiome, mainly through probiotics, is being tested to improve motor and non-motor symptoms and even to prevent PD. Finally, lipidomics has emerged as a useful tool to identify lipid biomarkers that may help analyze PD progression and treatment efficacy in a personalized manner, although, as of today, it has only scarcely been applied to monitor gut motility, dysbiosis, and probiotic effects in PD. Altogether, these new pieces should be helpful in solving the old puzzle of PD.
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Affiliation(s)
- Lorena Ortega Moreno
- Department of Basic Health Sciences, Faculty of Health Sciences, University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
- High Performance Research Group in Physiopathology and Pharmacology of the Digestive System (NeuGut-URJC), University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
| | - Ana Bagues
- Department of Basic Health Sciences, Faculty of Health Sciences, University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
- High Performance Research Group in Physiopathology and Pharmacology of the Digestive System (NeuGut-URJC), University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
- Associated I+D+i Unit to the Institute of Medicinal Chemistry (IQM), Scientific Research Superior Council (CSIC), 28006 Madrid, Spain
- High Performance Research Group in Experimental Pharmacology (PHARMAKOM-URJC), University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
| | - Vicente Martínez
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Neuroscience Institute, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28049 Madrid, Spain
| | - Raquel Abalo
- Department of Basic Health Sciences, Faculty of Health Sciences, University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
- High Performance Research Group in Physiopathology and Pharmacology of the Digestive System (NeuGut-URJC), University Rey Juan Carlos (URJC), 28922 Alcorcón, Spain
- Associated I+D+i Unit to the Institute of Medicinal Chemistry (IQM), Scientific Research Superior Council (CSIC), 28006 Madrid, Spain
- Working Group of Basic Sciences on Pain and Analgesia of the Spanish Pain Society, 28046 Madrid, Spain
- Working Group of Basic Sciences on Cannabinoids of the Spanish Pain Society, 28046 Madrid, Spain
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7
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Gervasi T, Mandalari G. The Interplay Between Gut Microbiota and Central Nervous System. Curr Pharm Des 2023; 29:3274-3281. [PMID: 38062662 DOI: 10.2174/0113816128264312231101110307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 09/14/2023] [Indexed: 01/26/2024]
Abstract
This review highlights the relationships between gastrointestinal microorganisms and the brain. The gut microbiota communicates with the central nervous system through nervous, endocrine, and immune signalling mechanisms. Our brain can modulate the gut microbiota structure and function through the autonomic nervous system, and possibly through neurotransmitters which directly act on bacterial gene expression. In this context, oxidative stress is one the main factors involved in the dysregulation of the gut-brain axis and consequently in neurodegenerative disorders. Several factors influence the susceptibility to oxidative stress by altering the antioxidant status or free oxygen radical generation. Amongst these, of interest is alcohol, a commonly used substance which can negatively influence the central nervous system and gut microbiota, with a key role in the development of neurodegenerative disorder. The role of "psychobiotics" as a novel contrast strategy for preventing and treating disorders caused due to alcohol use and abuse has been investigated.
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Affiliation(s)
- Teresa Gervasi
- Department of Biomedical and Dental Science and Morphofunctional Imaging, University of Messina, Messina 98166, Italy
| | - Giuseppina Mandalari
- Department of Chemical, Biological, Pharmaceutical and Environmental Science, University of Messina, Messina 98166, Italy
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Wang Y, Zhang Z, Li B, He B, Li L, Nice EC, Zhang W, Xu J. New Insights into the Gut Microbiota in Neurodegenerative Diseases from the Perspective of Redox Homeostasis. Antioxidants (Basel) 2022; 11:2287. [PMID: 36421473 PMCID: PMC9687622 DOI: 10.3390/antiox11112287] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/08/2022] [Accepted: 11/16/2022] [Indexed: 08/27/2023] Open
Abstract
An imbalance between oxidants and antioxidants in the body can lead to oxidative stress, which is one of the major causes of neurodegenerative diseases. The gut microbiota contains trillions of beneficial bacteria that play an important role in maintaining redox homeostasis. In the last decade, the microbiota-gut-brain axis has emerged as a new field that has revolutionized the study of the pathology, diagnosis, and treatment of neurodegenerative diseases. Indeed, a growing number of studies have found that communication between the brain and the gut microbiota can be accomplished through the endocrine, immune, and nervous systems. Importantly, dysregulation of the gut microbiota has been strongly associated with the development of oxidative stress-mediated neurodegenerative diseases. Therefore, a deeper understanding of the relationship between the gut microbiota and redox homeostasis will help explain the pathogenesis of neurodegenerative diseases from a new perspective and provide a theoretical basis for proposing new therapeutic strategies for neurodegenerative diseases. In this review, we will describe the role of oxidative stress and the gut microbiota in neurodegenerative diseases and the underlying mechanisms by which the gut microbiota affects redox homeostasis in the brain, leading to neurodegenerative diseases. In addition, we will discuss the potential applications of maintaining redox homeostasis by modulating the gut microbiota to treat neurodegenerative diseases, which could open the door for new therapeutic approaches to combat neurodegenerative diseases.
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Affiliation(s)
- Yu Wang
- West China School of Basic Medical Sciences & Forensic Medicine, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Zhe Zhang
- West China School of Basic Medical Sciences & Forensic Medicine, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Bowen Li
- West China School of Basic Medical Sciences & Forensic Medicine, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Bo He
- West China School of Basic Medical Sciences & Forensic Medicine, and State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu 610041, China
| | - Lei Li
- School of Basic Medical Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Edouard C. Nice
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Wei Zhang
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu 610041, China
- Mental Health Center and Psychiatric Laboratory, the State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu 610000, China
| | - Jia Xu
- School of Medicine, Ningbo University, Ningbo 315211, China
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Avagliano C, Coretti L, Lama A, Pirozzi C, De Caro C, De Biase D, Turco L, Mollica MP, Paciello O, Calignano A, Meli R, Lembo F, Mattace Raso G. Dual-Hit Model of Parkinson's Disease: Impact of Dysbiosis on 6-Hydroxydopamine-Insulted Mice-Neuroprotective and Anti-Inflammatory Effects of Butyrate. Int J Mol Sci 2022; 23:ijms23126367. [PMID: 35742813 PMCID: PMC9223521 DOI: 10.3390/ijms23126367] [Citation(s) in RCA: 10] [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: 04/29/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 02/04/2023] Open
Abstract
Recent evidence highlights Parkinson’s disease (PD) initiation in the gut as the prodromal phase of neurodegeneration. Gut impairment due to microbial dysbiosis could affect PD pathogenesis and progression. Here, we propose a two-hit model of PD through ceftriaxone (CFX)-induced dysbiosis and gut inflammation before the 6-hydroxydopamine (6-OHDA) intrastriatal injection to mimic dysfunctional gut-associated mechanisms preceding PD onset. Therefore, we showed that dysbiosis and gut damage amplified PD progression, worsening motor deficits induced by 6-OHDA up to 14 days post intrastriatal injection. This effect was accompanied by a significant increase in neuronal dopaminergic loss (reduced tyrosine hydroxylase expression and increased Bcl-2/Bax ratio). Notably, CFX pretreatment also enhanced systemic and colon inflammation of dual-hit subjected mice. The exacerbated inflammatory response ran in tandem with a worsening of colonic architecture and gut microbiota perturbation. Finally, we demonstrated the beneficial effect of post-biotic sodium butyrate in limiting at once motor deficits, neuroinflammation, and colon damage and re-shaping microbiota composition in this novel dual-hit model of PD. Taken together, the bidirectional communication of the microbiota–gut–brain axis and the recapitulation of PD prodromal/pathogenic features make this new paradigm a useful tool for testing or repurposing new multi-target compounds in the treatment of PD.
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Affiliation(s)
- Carmen Avagliano
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
| | - Lorena Coretti
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
- Task Force on Microbiome Studies, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy;
| | - Adriano Lama
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
- Task Force on Microbiome Studies, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy;
- Correspondence: (A.L.); (G.M.R.); Tel.: +39-081678409 (A.L.); Tel.: +39-081678423 (G.M.R.)
| | - Claudio Pirozzi
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
| | - Carmen De Caro
- Department of Science of Health, School of Medicine, University Magna Graecia of Catanzaro, Viale Europa, 88100 Catanzaro, Italy;
| | - Davide De Biase
- Department of Pharmacy, University of Salerno, 84084 Fisciano, Italy;
| | - Luigia Turco
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, 80138 Naples, Italy
| | - Maria Pina Mollica
- Task Force on Microbiome Studies, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy;
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, Cupa Nuova Cinthia 21 Edificio, 80126 Naples, Italy
| | - Orlando Paciello
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Delpino, 80137 Naples, Italy;
| | - Antonio Calignano
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
| | - Rosaria Meli
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
| | - Francesca Lembo
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
- Task Force on Microbiome Studies, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy;
| | - Giuseppina Mattace Raso
- Department of Pharmacy, School of Medicine, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy; (C.A.); (L.C.); (C.P.); (L.T.); (A.C.); (R.M.); (F.L.)
- Task Force on Microbiome Studies, University of Naples Federico II, Via Domenico Montesano, 80131 Naples, Italy;
- Correspondence: (A.L.); (G.M.R.); Tel.: +39-081678409 (A.L.); Tel.: +39-081678423 (G.M.R.)
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Shandilya S, Kumar S, Kumar Jha N, Kumar Kesari K, Ruokolainen J. Interplay of gut microbiota and oxidative stress: Perspective on neurodegeneration and neuroprotection. J Adv Res 2022; 38:223-244. [PMID: 35572407 PMCID: PMC9091761 DOI: 10.1016/j.jare.2021.09.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/05/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Background Recent research on the implications of gut microbiota on brain functions has helped to gather important information on the relationship between them. Pathogenesis of neurological disorders is found to be associated with dysregulation of gut-brain axis. Some gut bacteria metabolites are found to be directly associated with the increase in reactive oxygen species levels, one of the most important risk factors of neurodegeneration. Besides their morbid association, gut bacteria metabolites are also found to play a significant role in reducing the onset of these life-threatening brain disorders. Aim of Review Studies done in the recent past raises two most important link between gut microbiota and the brain: "gut microbiota-oxidative stress-neurodegeneration" and gut microbiota-antioxidant-neuroprotection. This review aims to gives a deep insight to our readers, of the collective studies done, focusing on the gut microbiota mediated oxidative stress involved in neurodegeneration along with a focus on those studies showing the involvement of gut microbiota and their metabolites in neuroprotection. Key Scientific Concepts of Review This review is focused on three main key concepts. Firstly, the mounting evidences from clinical and preclinical arenas shows the influence of gut microbiota mediated oxidative stress resulting in dysfunctional neurological processes. Therefore, we describe the potential role of gut microbiota influencing the vulnerability of brain to oxidative stress, and a budding causative in Alzheimer's and Parkinson's disease. Secondly, contributing roles of gut microbiota has been observed in attenuating oxidative stress and inflammation via its own metabolites or by producing secondary metabolites and, also modulation in gut microbiota population with antioxidative and anti-inflammatory probiotics have shown promising neuro resilience. Thirdly, high throughput in silico tools and databases also gives a correlation of gut microbiome, their metabolites and brain health, thus providing fascinating perspective and promising new avenues for therapeutic options.
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Affiliation(s)
- Shruti Shandilya
- Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
| | - Sandeep Kumar
- Department of Biochemistry, International Institute of Veterinary Education and Research, Haryana, India
- Clinical Science, Targovax Oy, Saukonpaadenranta 2, Helsinki 00180, Finland
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering and Technology (SET), Sharda University, Plot no. 32–34, Knowledge Park III, Greater Noida 201310, India
| | | | - Janne Ruokolainen
- Department of Applied Physics, School of Science, Aalto University, Espoo, Finland
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Zhao L, Ren P, Wang M, Wang J, He X, Gu J, Lu Y, Wu Y, Liu J, Wang L, Li H. Changes in intestinal barrier protein expression and intestinal flora in a rat model of visceral hypersensitivity. Neurogastroenterol Motil 2022; 34:e14299. [PMID: 34821442 DOI: 10.1111/nmo.14299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 08/30/2021] [Accepted: 11/10/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Destruction of the intestinal mucosal barrier and visceral hypersensitivity are main pathogenesis of irritable bowel syndrome (IBS). The study aimed to establish a rat model of visceral hypersensitivity and explore mechanisms involved the changes of the intestinal barrier protein expression and intestinal flora. METHODS A rat model of visceral hypersensitivity was established and evaluated using abdominal withdrawal reflex (AWR) scores, colonic paracellular permeability, and gastrointestinal motility. The expression of tight junction proteins, aquaporin proteins (AQPs), phosphorylated ERK, and proteinase-activated receptor-2 (PAR-2) was determined. The intestinal microflora was evaluated by high-throughput sequencing of the 16S rRNA gene. KEY RESULTS In model rats, AWR score and fecal water content were significantly increased, gastrointestinal motilities were disorder and characterized by an inhibition of gastric motility and an enhancement of small intestinal and colonic movement. The expressions of colonic occludin, ZO-1, AQP3, and AQP8 were decreased but claudin-2 and claudin-4 were markedly increased. Imbalance of intestinal flora appeared and showed an obvious decrease of Lactobacillus and an increase of Clostridiales_bacterium. Additionally, the total serine protease activity in feces, the expressions of PAR2 and phosphorylated ERK in the colon tissues were increased significantly. CONCLUSION AND INFERENCES The model rats of visceral hypersensitivity possess the decreased expression of occludin, ZO-1, AQP3, AQP8, and the increased expression of claudin-2 and claudin-4, meanwhile develop an imbalance of intestinal flora which probably increase serine protease activity, thereby activating the PAR2/ERK signaling and causing the intestinal barrier disorder.
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Affiliation(s)
- Li Zhao
- Department of Physiology, College of Basic Medicine, Lanzhou University, Lanzhou, China
| | - Peipei Ren
- Affiliated Hospital, Gansu University of Chinese Medicine, Lanzhou, China
| | - Miaolei Wang
- Affiliated Hospital, Gansu University of Chinese Medicine, Lanzhou, China
| | - Jingjing Wang
- Department of Physiology, College of Basic Medicine, Lanzhou University, Lanzhou, China
| | - Xueyun He
- Department of Physiology, College of Basic Medicine, Lanzhou University, Lanzhou, China
| | - Jingyan Gu
- Department of Physiology, College of Basic Medicine, Lanzhou University, Lanzhou, China
| | - Yanyu Lu
- Function Laboratory in College of Basic Medicine, Lanzhou University, Lanzhou, Gansu Province, China
| | - Yana Wu
- Affiliated Hospital, Gansu University of Chinese Medicine, Lanzhou, China
| | - Junhong Liu
- Affiliated Hospital, Gansu University of Chinese Medicine, Lanzhou, China
| | - Longde Wang
- Affiliated Hospital, Gansu University of Chinese Medicine, Lanzhou, China
| | - Hongfang Li
- Department of Physiology, College of Basic Medicine, Lanzhou University, Lanzhou, China.,Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Lanzhou, China
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12
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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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13
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Nakamori H, Noda K, Mitsui R, Hashitani H. Role of enteric dopaminergic neurons in regulating peristalsis of rat proximal colon. Neurogastroenterol Motil 2021; 33:e14127. [PMID: 33939231 DOI: 10.1111/nmo.14127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/11/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022]
Abstract
BACKGROUND Constipation is commonly seen in patients with Parkinson's disease associated with a loss of dopaminergic neurons in both central and enteric nervous systems. However, the roles of enteric dopaminergic neurons in developing constipation remain to be elucidated. Here, we investigated the roles of enteric dopaminergic neurons in the generation of colonic peristalsis. METHODS Cannulated segments of rat proximal colon were situated in the organ bath, abluminally perfused with physiological salt solution and luminally perfused with 0.9% saline. Drugs were applied in the abluminal solution. Changes in diameter along the length of the colonic segment were captured by a video camera and transformed into spatio-temporal maps. Fluorescence immunohistochemistry was also carried out. KEY RESULTS Blockade of nitrergic neurotransmission prevented oro-aboral propagation of peristaltic waves and caused a colonic constriction without affecting ripples, non-propagating myogenic contractions. Blockade of cholinergic neurotransmission also prevented peristaltic waves but suppressed ripples with a colonic dilatation. Tetrodotoxin (0.6 μM) abolished peristaltic waves and increased ripples with a constriction. SCH 23390 (20 μM), a D1 -like dopamine receptor antagonist, slowed the peristaltic waves and caused a constriction, while GBR 12909 (1 μM), a dopamine reuptake inhibitor, diminished the peristaltic waves with a dilatation. Bath-applied dopamine (3 μM) abolished the peristaltic waves associated with a colonic dilation in an SCH 23390 (5 μM)-sensitive manner. D1 receptor immunoreactivity was co-localized to nitrergic and cholinergic neurons. CONCLUSIONS AND INFERENCES Dopaminergic neurons appear to facilitate nitrergic neurons via D1 -like receptors to stabilize asynchronous contractile activity resulting in the generation of colonic peristalsis.
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Affiliation(s)
- Hiroyuki Nakamori
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kenta Noda
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hikaru Hashitani
- Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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McQuade RM, Singleton LM, Wu H, Lee S, Constable R, Di Natale M, Ringuet MT, Berger JP, Kauhausen J, Parish CL, Finkelstein DI, Furness JB, Diwakarla S. The association of enteric neuropathy with gut phenotypes in acute and progressive models of Parkinson's disease. Sci Rep 2021; 11:7934. [PMID: 33846426 PMCID: PMC8041759 DOI: 10.1038/s41598-021-86917-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/10/2021] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) is associated with neuronal damage in the brain and gut. This work compares changes in the enteric nervous system (ENS) of commonly used mouse models of PD that exhibit central neuropathy and a gut phenotype. Enteric neuropathy was assessed in five mouse models: peripheral injection of MPTP; intracerebral injection of 6-OHDA; oral rotenone; and mice transgenic for A53T variant human α-synuclein with and without rotenone. Changes in the ENS of the colon were quantified using pan-neuronal marker, Hu, and neuronal nitric oxide synthase (nNOS) and were correlated with GI function. MPTP had no effect on the number of Hu+ neurons but was associated with an increase in Hu+ nuclear translocation (P < 0.04). 6-OHDA lesioned mice had significantly fewer Hu+ neurons/ganglion (P < 0.02) and a reduced proportion of nNOS+ neurons in colon (P < 0.001). A53T mice had significantly fewer Hu+ neurons/area (P < 0.001) and exhibited larger soma size (P < 0.03). Treatment with rotenone reduced the number of Hu+ cells/mm2 in WT mice (P < 0.006) and increased the proportion of Hu+ translocated cells in both WT (P < 0.02) and A53T mice (P < 0.04). All PD models exhibited a degree of enteric neuropathy, the extent and type of damage to the ENS, however, was dependent on the model.
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Affiliation(s)
- Rachel M McQuade
- Department of Medicine, Western Health, Melbourne University, Sunshine, VIC, 3021, Australia.
- College of Health and Biomedicine, Victoria University, Sunshine, VIC, 3021, Australia.
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia.
| | - Lewis M Singleton
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - Hongyi Wu
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sophie Lee
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Remy Constable
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - Madeleine Di Natale
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - Mitchell T Ringuet
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | | | - Jessica Kauhausen
- Stem Cells and Neural Development Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - Clare L Parish
- Stem Cells and Neural Development Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - David I Finkelstein
- Parkinson's Disease Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
| | - John B Furness
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Shanti Diwakarla
- Department of Medicine, Western Health, Melbourne University, Sunshine, VIC, 3021, Australia
- Digestive Physiology and Nutrition Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3010, Australia
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15
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The gut microbiota-brain axis in behaviour and brain disorders. Nat Rev Microbiol 2020; 19:241-255. [PMID: 33093662 DOI: 10.1038/s41579-020-00460-0] [Citation(s) in RCA: 810] [Impact Index Per Article: 202.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 02/06/2023]
Abstract
In a striking display of trans-kingdom symbiosis, gut bacteria cooperate with their animal hosts to regulate the development and function of the immune, metabolic and nervous systems through dynamic bidirectional communication along the 'gut-brain axis'. These processes may affect human health, as certain animal behaviours appear to correlate with the composition of gut bacteria, and disruptions in microbial communities have been implicated in several neurological disorders. Most insights about host-microbiota interactions come from animal models, which represent crucial tools for studying the various pathways linking the gut and the brain. However, there are complexities and manifest limitations inherent in translating complex human disease to reductionist animal models. In this Review, we discuss emerging and exciting evidence of intricate and crucial connections between the gut microbiota and the brain involving multiple biological systems, and possible contributions by the gut microbiota to neurological disorders. Continued advances from this frontier of biomedicine may lead to tangible impacts on human health.
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