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Mahbub NU, Islam MM, Hong ST, Chung HJ. Dysbiosis of the gut microbiota and its effect on α-synuclein and prion protein misfolding: consequences for neurodegeneration. Front Cell Infect Microbiol 2024; 14:1348279. [PMID: 38435303 PMCID: PMC10904658 DOI: 10.3389/fcimb.2024.1348279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 01/24/2024] [Indexed: 03/05/2024] Open
Abstract
Abnormal behavior of α-synuclein and prion proteins is the hallmark of Parkinson's disease (PD) and prion illnesses, respectively, being complex neurological disorders. A primary cause of protein aggregation, brain injury, and cognitive loss in prion illnesses is the misfolding of normal cellular prion proteins (PrPC) into an infectious form (PrPSc). Aggregation of α-synuclein causes disruptions in cellular processes in Parkinson's disease (PD), leading to loss of dopamine-producing neurons and motor symptoms. Alteration in the composition or activity of gut microbes may weaken the intestinal barrier and make it possible for prions to go from the gut to the brain. The gut-brain axis is linked to neuroinflammation; the metabolites produced by the gut microbiota affect the aggregation of α-synuclein, regulate inflammation and immunological responses, and may influence the course of the disease and neurotoxicity of proteins, even if their primary targets are distinct proteins. This thorough analysis explores the complex interactions that exist between the gut microbiota and neurodegenerative illnesses, particularly Parkinson's disease (PD) and prion disorders. The involvement of the gut microbiota, a complex collection of bacteria, archaea, fungi, viruses etc., in various neurological illnesses is becoming increasingly recognized. The gut microbiome influences neuroinflammation, neurotransmitter synthesis, mitochondrial function, and intestinal barrier integrity through the gut-brain axis, which contributes to the development and progression of disease. The review delves into the molecular mechanisms that underlie these relationships, emphasizing the effects of microbial metabolites such as bacterial lipopolysaccharides (LPS), and short-chain fatty acids (SCFAs) in regulating brain functioning. Additionally, it looks at how environmental influences and dietary decisions affect the gut microbiome and whether they could be risk factors for neurodegenerative illnesses. This study concludes by highlighting the critical role that the gut microbiota plays in the development of Parkinson's disease (PD) and prion disease. It also provides a promising direction for future research and possible treatment approaches. People afflicted by these difficult ailments may find hope in new preventive and therapeutic approaches if the role of the gut microbiota in these diseases is better understood.
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Affiliation(s)
- Nasir Uddin Mahbub
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Md Minarul Islam
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Seong-Tshool Hong
- Department of Biomedical Sciences and Institute for Medical Science, Jeonbuk National University Medical School, Jeonju, Republic of Korea
| | - Hea-Jong Chung
- Gwangju Center, Korea Basic Science Institute, Gwangju, Republic of Korea
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Dissanayaka DMS, Jayasena V, Rainey-Smith SR, Martins RN, Fernando WMADB. The Role of Diet and Gut Microbiota in Alzheimer's Disease. Nutrients 2024; 16:412. [PMID: 38337696 PMCID: PMC10857293 DOI: 10.3390/nu16030412] [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: 12/30/2023] [Revised: 01/22/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
Alzheimer's disease (AD), the most prevalent form of dementia, is characterized by the accumulation of amyloid-beta (Aβ) plaques and hyperphosphorylated tau tangles. Currently, Alzheimer's disease (AD) impacts 50 million individuals, with projections anticipating an increase to 152 million by the year 2050. Despite the increasing global prevalence of AD, its underlying pathology remains poorly understood, posing challenges for early diagnosis and treatment. Recent research suggests a link between gut dysbiosis and the aggregation of Aβ, the development of tau proteins, and the occurrence of neuroinflammation and oxidative stress are associated with AD. However, investigations into the gut-brain axis (GBA) in the context of AD progression and pathology have yielded inconsistent findings. This review aims to enhance our understanding of microbial diversity at the species level and the role of these species in AD pathology. Additionally, this review addresses the influence of confounding elements, including diet, probiotics, and prebiotics, on AD throughout different stages (preclinical, mild cognitive impairment (MCI), and AD) of its progression.
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Affiliation(s)
- D. M. Sithara Dissanayaka
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia; (D.M.S.D.); (S.R.R.-S.); (R.N.M.)
- Alzheimer’s Research Australia, Ralph and Patricia Sarich Neuroscience Research Institute, Nedlands, WA 6009, Australia
| | - Vijay Jayasena
- School of Science and Health, Western Sydney University, M15, Rm. G54, Locked Bag 1797, Penrith, NSW 2751, Australia;
| | - Stephanie R. Rainey-Smith
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia; (D.M.S.D.); (S.R.R.-S.); (R.N.M.)
- Alzheimer’s Research Australia, Ralph and Patricia Sarich Neuroscience Research Institute, Nedlands, WA 6009, Australia
- Centre for Healthy Aging, Murdoch University, Murdoch, WA 6150, Australia
| | - Ralph N. Martins
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia; (D.M.S.D.); (S.R.R.-S.); (R.N.M.)
- Alzheimer’s Research Australia, Ralph and Patricia Sarich Neuroscience Research Institute, Nedlands, WA 6009, Australia
- Department of Biomedical Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - W. M. A. D. Binosha Fernando
- Centre of Excellence for Alzheimer’s Disease Research & Care, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA 6027, Australia; (D.M.S.D.); (S.R.R.-S.); (R.N.M.)
- Alzheimer’s Research Australia, Ralph and Patricia Sarich Neuroscience Research Institute, Nedlands, WA 6009, Australia
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Troci A, Philippen S, Rausch P, Rave J, Weyland G, Niemann K, Jessen K, Schmill LP, Aludin S, Franke A, Berg D, Bang C, Bartsch T. Disease- and stage-specific alterations of the oral and fecal microbiota in Alzheimer's disease. PNAS NEXUS 2024; 3:pgad427. [PMID: 38205031 PMCID: PMC10776369 DOI: 10.1093/pnasnexus/pgad427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 11/30/2023] [Indexed: 01/12/2024]
Abstract
Microbial communities in the intestinal tract are suggested to impact the ethiopathogenesis of Alzheimer's disease (AD). The human microbiome might modulate neuroinflammatory processes and contribute to neurodegeneration in AD. However, the microbial compositions in patients with AD at different stages of the disease are still not fully characterized. We used 16S rRNA analyses to investigate the oral and fecal microbiota in patients with AD and mild cognitive impairment (MCI; n = 84), at-risk individuals (APOE4 carriers; n = 17), and healthy controls (n = 50) and investigated the relationship of microbial communities and disease-specific markers via multivariate- and network-based approaches. We found a slightly decreased diversity in the fecal microbiota of patients with AD (average Chao1 diversity for AD = 212 [SD = 66]; for controls = 215 [SD = 55]) and identified differences in bacterial abundances including Bacteroidetes, Ruminococcus, Sutterella, and Porphyromonadaceae. The diversity in the oral microbiota was increased in patients with AD and at-risk individuals (average Chao1 diversity for AD = 174 [SD = 60], for at-risk group = 195 [SD = 49]). Gram-negative proinflammatory bacteria including Haemophilus, Neisseria, Actinobacillus, and Porphyromonas were dominant oral bacteria in patients with AD and MCI and the abundance correlated with the cerebrospinal fluid biomarker. Taken together, we observed a strong shift in the fecal and the oral communities of patients with AD already prominent in prodromal and, in case of the oral microbiota, in at-risk stages. This indicates stage-dependent alterations in oral and fecal microbiota in AD which may contribute to the pathogenesis via a facilitated intestinal and systemic inflammation leading to neuroinflammation and neurodegeneration.
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Affiliation(s)
- Alba Troci
- Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany
| | - Sarah Philippen
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Philipp Rausch
- Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany
| | - Julius Rave
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Gina Weyland
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Katharina Niemann
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Katharina Jessen
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Lars-Patrick Schmill
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Schekeb Aludin
- Department of Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany
| | - Daniela Berg
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
| | - Corinna Bang
- Institute of Clinical Molecular Biology, Kiel University, Kiel, Germany
| | - Thorsten Bartsch
- Department of Neurology, Memory Disorders and Plasticity Group, University Hospital Schleswig-Holstein, Kiel 24105, Germany
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Diet-induced gut dysbiosis and inflammation: Key drivers of obesity-driven NASH. iScience 2022; 26:105905. [PMID: 36691622 PMCID: PMC9860397 DOI: 10.1016/j.isci.2022.105905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sucrose, the primary circulating sugar in plants, contains equal amounts of fructose and glucose. The latter is the predominant circulating sugar in animals and thus the primary fuel source for various tissue and cell types in the body. Chronic excessive energy intake has, however, emerged as a major driver of obesity and associated pathologies including nonalcoholic fatty liver diseases (NAFLD) and the more severe nonalcoholic steatohepatitis (NASH). Consumption of a high-caloric, western-style diet induces gut dysbiosis and inflammation resulting in leaky gut. Translocation of gut-derived bacterial content promotes hepatic inflammation and ER stress, and when either or both of these are combined with steatosis, it can cause NASH. Here, we review the metabolic links between diet-induced changes in the gut and NASH. Furthermore, therapeutic interventions for the treatment of obesity and liver metabolic diseases are also discussed with a focus on restoring the gut-liver axis.
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Cuesta CM, Pascual M, Pérez-Moraga R, Rodríguez-Navarro I, García-García F, Ureña-Peralta JR, Guerri C. TLR4 Deficiency Affects the Microbiome and Reduces Intestinal Dysfunctions and Inflammation in Chronic Alcohol-Fed Mice. Int J Mol Sci 2021; 22:ijms222312830. [PMID: 34884634 PMCID: PMC8657603 DOI: 10.3390/ijms222312830] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 12/21/2022] Open
Abstract
Chronic alcohol abuse causes an inflammatory response in the intestinal tract with damage to the integrity of the mucosa and epithelium, as well as dysbiosis in the gut microbiome. However, the role of gut bacteria in ethanol effects and how these microorganisms interact with the immune system are not well understood. The aim of the present study was to evaluate if TLR4 alters the ethanol-induced intestinal inflammatory response, and whether the response of this receptor affects the gut microbiota profile. We analyzed the 16S rRNA sequence of the fecal samples from wild-type (WT) and TLR4-knockout (TLR4-KO) mice with and without ethanol intake for 3 months. The results demonstrated that chronic ethanol consumption reduces microbiota diversity and causes dysbiosis in WT mice. Likewise, ethanol upregulates several inflammatory genes (IL-1β, iNOS, TNF-α) and miRNAs (miR-155-5p, miR-146a-5p) and alters structural and permeability genes (INTL1, CDH1, CFTR) in the colon of WT mice. Our results further demonstrated that TLR4-KO mice exhibit a different microbiota that can protect against the ethanol-induced activation of the immune system and colon integrity dysfunctions. In short, our results reveal that TLR4 is a key factor for determining the gut microbiota, which can participate in dysbiosis and the inflammatory response induced by alcohol consumption.
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Affiliation(s)
- Carlos M. Cuesta
- Department of Molecular and Cellular Pathology of Alcohol, Prince Felipe Research Center, 46012 Valencia, Spain; (C.M.C.); (M.P.); (I.R.-N.)
| | - María Pascual
- Department of Molecular and Cellular Pathology of Alcohol, Prince Felipe Research Center, 46012 Valencia, Spain; (C.M.C.); (M.P.); (I.R.-N.)
- Department of Physiology, School of Medicine and Dentistry, University of Valencia, 15 Avda. Blasco Ibanez, 46010 Valencia, Spain
| | - Raúl Pérez-Moraga
- Bioinformatics and Biostatistics Unit, Prince Felipe Research Center, 46012 Valencia, Spain; (R.P.-M.); (F.G.-G.)
| | - Irene Rodríguez-Navarro
- Department of Molecular and Cellular Pathology of Alcohol, Prince Felipe Research Center, 46012 Valencia, Spain; (C.M.C.); (M.P.); (I.R.-N.)
| | - Francisco García-García
- Bioinformatics and Biostatistics Unit, Prince Felipe Research Center, 46012 Valencia, Spain; (R.P.-M.); (F.G.-G.)
| | - Juan R. Ureña-Peralta
- Department of Molecular and Cellular Pathology of Alcohol, Prince Felipe Research Center, 46012 Valencia, Spain; (C.M.C.); (M.P.); (I.R.-N.)
- Correspondence: (J.R.U.-P.); (C.G.)
| | - Consuelo Guerri
- Department of Molecular and Cellular Pathology of Alcohol, Prince Felipe Research Center, 46012 Valencia, Spain; (C.M.C.); (M.P.); (I.R.-N.)
- Correspondence: (J.R.U.-P.); (C.G.)
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Kittana M, Ahmadani A, Al Marzooq F, Attlee A. Dietary Fat Effect on the Gut Microbiome, and Its Role in the Modulation of Gastrointestinal Disorders in Children with Autism Spectrum Disorder. Nutrients 2021; 13:3818. [PMID: 34836074 PMCID: PMC8618510 DOI: 10.3390/nu13113818] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/23/2021] [Accepted: 10/24/2021] [Indexed: 12/19/2022] Open
Abstract
Children with autism spectrum disorder (ASD) report a higher frequency and severity of gastrointestinal disorders (GID) than typically developing (TD) children. GID-associated discomfort increases feelings of anxiety and frustration, contributing to the severity of ASD. Emerging evidence supports the biological intersection of neurodevelopment and microbiome, indicating the integral contribution of GM in the development and function of the nervous system, and mental health, and disease balance. Dysbiotic GM could be a contributing factor in the pathogenesis of GID in children with ASD. High-fat diets may modulate GM through accelerated growth of bile-tolerant bacteria, altered bacterial ratios, and reduced bacterial diversity, which may increase the risk of GID. Notably, saturated fatty acids are considered to have a pronounced effect on the increase of bile-tolerant bacteria and reduction in microbial diversity. Additionally, omega-3 exerts a favorable impact on GM and gut health due to its anti-inflammatory properties. Despite inconsistencies in the data elaborated in the review, the dietary fat composition, as part of an overall dietary intervention, plays a role in modulating GID, specifically in ASD, due to the altered microbiome profile. This review emphasizes the need to conduct future experimental studies investigating the effect of diets with varying fatty acid compositions on GID-specific microbiome profiles in children with ASD.
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Affiliation(s)
- Monia Kittana
- Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates; (M.K.); (A.A.)
| | - Asma Ahmadani
- Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates; (M.K.); (A.A.)
| | - Farah Al Marzooq
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates;
| | - Amita Attlee
- Department of Nutrition and Health, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates; (M.K.); (A.A.)
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