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Kang JW, Vemuganti V, Kuehn JF, Ulland TK, Rey FE, Bendlin BB. Gut microbial metabolism in Alzheimer's disease and related dementias. Neurotherapeutics 2024; 21:e00470. [PMID: 39462700 PMCID: PMC11585892 DOI: 10.1016/j.neurot.2024.e00470] [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: 07/29/2024] [Revised: 09/30/2024] [Accepted: 10/04/2024] [Indexed: 10/29/2024] Open
Abstract
Multiple studies over the last decade have established that Alzheimer's disease and related dementias (ADRD) are associated with changes in the gut microbiome. These alterations in organismal composition result in changes in the abundances of functions encoded by the microbial community, including metabolic capabilities, which likely impact host disease mechanisms. Gut microbes access dietary components and other molecules made by the host and produce metabolites that can enter circulation and cross the blood-brain barrier (BBB). In recent years, several microbial metabolites have been associated with or have been shown to influence host pathways relevant to ADRD pathology. These include short chain fatty acids, secondary bile acids, tryptophan derivatives (such as kynurenine, serotonin, tryptamine, and indoles), and trimethylamine/trimethylamine N-oxide. Notably, some of these metabolites cross the BBB and can have various effects on the brain, including modulating the release of neurotransmitters and neuronal function, inducing oxidative stress and inflammation, and impacting synaptic function. Microbial metabolites can also impact the central nervous system through immune, enteroendocrine, and enteric nervous system pathways, these perturbations in turn impact the gut barrier function and peripheral immune responses, as well as the BBB integrity, neuronal homeostasis and neurogenesis, and glial cell maturation and activation. This review examines the evidence supporting the notion that ADRD is influenced by gut microbiota and its metabolites. The potential therapeutic advantages of microbial metabolites for preventing and treating ADRD are also discussed, highlighting their potential role in developing new treatments.
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Affiliation(s)
- Jea Woo Kang
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Vaibhav Vemuganti
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jessamine F Kuehn
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Tyler K Ulland
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Federico E Rey
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
| | - Barbara B Bendlin
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Wisconsin Alzheimer's Institute, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA.
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Shrestha D, Pant B, Roychowdhury S, Gandhirajan A, Cross E, Chhabria M, Bauer S, Jeng M, Mitchell M, Mehkri O, Zaidi F, Ahuja A, Wang X, Wang Y, McDonald C, Longworth M, Stappenbeck T, Stark GR, Scheraga R, Vachharajani V. Immunometabolic Chaos in Septic Shock. J Leukoc Biol 2024:qiae211. [PMID: 39340428 DOI: 10.1093/jleuko/qiae211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Revised: 08/09/2024] [Accepted: 09/26/2024] [Indexed: 09/30/2024] Open
Abstract
Septic shock is associated with over 40% mortality. The immune response in septic shock is tightly regulated by cellular metabolism and transitions from early hyper-inflammation to later hypo-inflammation. Patients are susceptible to secondary infections during hypo-inflammation. The magnitude of the metabolic dysregulation and the effect of plasma metabolites on the circulating immune cells in septic shock are not reported. We hypothesized that the accumulated plasma metabolites affect the immune response in septic shock during hypo-inflammation. Our study took a unique approach. Using peripheral blood from adult septic shock patients and healthy controls, we studied: 1. Whole blood stimulation ± E. Coli lipopolysaccharide (LPS: endotoxin) to analyze plasma TNF protein, and 2. Plasma metabolomic profile by Metabolon. Inc. 3. We exposed peripheral blood mononuclear cells (PBMCs) from healthy controls to commercially available carbohydrate, amino acid, and fatty acid metabolites and studied the response to LPS. We report that: 1. The whole blood stimulation of the healthy control group showed a significantly upregulated TNF protein, while the septic shock group remained endotoxin tolerant, a biomarker for hypo-inflammation. 2. A significant accumulation of carbohydrate, amino acid, fatty acid, ceramide, sphingomyelin, and TCA cycle pathway metabolites in septic shock plasma. 3. In vitro exposure to five metabolites repressed while two metabolites upregulated the inflammatory response of PBMCs to LPS. We conclude that the endotoxin-tolerant phenotype of septic shock is associated with a simultaneous accumulation of plasma metabolites from multiple metabolic pathways, and these metabolites fundamentally influence the immune response profile of circulating cells.
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Affiliation(s)
- Deepmala Shrestha
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
| | - Bishnu Pant
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
| | | | | | - Emily Cross
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
| | - Mamta Chhabria
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | | | - Margaret Jeng
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | - Megan Mitchell
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | - Omar Mehkri
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | - Fatima Zaidi
- Discovery and Translational Science, Metabolon, Morrisville, North Carolina
| | - Akash Ahuja
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
| | - Xiaofeng Wang
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | - Yuxin Wang
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
| | | | | | | | - George R Stark
- Cancer Biology, Lerner Research Institute, Cleveland OH, USA
| | - Rachel Scheraga
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
| | - Vidula Vachharajani
- Inflammation and Immunity, Cleveland Clinic Lerner Research Institute
- Pulmonary and Critical Care, Cleveland Clinic Integrated Hospital Care Institute
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Elfers K, Watanangura A, Hoffmann P, Suchodolski JS, Khattab MR, Pilla R, Meller S, Volk HA, Mazzuoli-Weber G. Fecal supernatants from dogs with idiopathic epilepsy activate enteric neurons. Front Neurosci 2024; 18:1281840. [PMID: 38356649 PMCID: PMC10864448 DOI: 10.3389/fnins.2024.1281840] [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] [Received: 08/23/2023] [Accepted: 01/15/2024] [Indexed: 02/16/2024] Open
Abstract
Introduction Alterations in the composition and function of the gut microbiome have been reported in idiopathic epilepsy (IE), however, interactions of gut microbes with the enteric nervous system (ENS) in this context require further study. This pilot study examined how gastrointestinal microbiota (GIM), their metabolites, and nutrients contained in intestinal contents communicate with the ENS. Methods Fecal supernatants (FS) from healthy dogs and dogs with IE, including drug-naïve, phenobarbital (PB) responsive, and PB non-responsive dogs, were applied to cultured myenteric neurons to test their activation using voltage-sensitive dye neuroimaging. Additionally, the concentrations of short-chain fatty acids (SCFAs) in the FS were quantified. Results Our findings indicate that FS from all examined groups elicited neuronal activation. Notably, FS from PB non-responsive dogs with IE induced action potential discharge in a higher proportion of enteric neurons compared to healthy controls, which exhibited the lowest burst frequency overall. Furthermore, the highest burst frequency in enteric neurons was observed upon exposure to FS from drug-naïve dogs with IE. This frequency was significantly higher compared to that observed in PB non-responsive dogs with IE and showed a tendency to surpass that of healthy controls. Discussion Although observed disparities in SCFA concentrations across the various FS samples might be associated with the induced neuronal activity, a direct correlation remains elusive at this point. The obtained results hint at an involvement of the ENS in canine IE and set the basis for future studies.
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Affiliation(s)
- Kristin Elfers
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Antja Watanangura
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
- Veterinary Research and Academic Service, Faculty of Veterinary Medicine, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand
| | - Pascal Hoffmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Jan S. Suchodolski
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, Texas A&M University, College Station, TX, United States
| | - Mohammad R. Khattab
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, Texas A&M University, College Station, TX, United States
| | - Rachel Pilla
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, Texas A&M University, College Station, TX, United States
| | - Sebastian Meller
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
| | - Holger A. Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Gemma Mazzuoli-Weber
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover Foundation, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
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Nohesara S, Abdolmaleky HM, Zhou JR, Thiagalingam S. Microbiota-Induced Epigenetic Alterations in Depressive Disorders Are Targets for Nutritional and Probiotic Therapies. Genes (Basel) 2023; 14:2217. [PMID: 38137038 PMCID: PMC10742434 DOI: 10.3390/genes14122217] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Major depressive disorder (MDD) is a complex disorder and a leading cause of disability in 280 million people worldwide. Many environmental factors, such as microbes, drugs, and diet, are involved in the pathogenesis of depressive disorders. However, the underlying mechanisms of depression are complex and include the interaction of genetics with epigenetics and the host immune system. Modifications of the gut microbiome and its metabolites influence stress-related responses and social behavior in patients with depressive disorders by modulating the maturation of immune cells and neurogenesis in the brain mediated by epigenetic modifications. Here, we discuss the potential roles of a leaky gut in the development of depressive disorders via changes in gut microbiota-derived metabolites with epigenetic effects. Next, we will deliberate how altering the gut microbiome composition contributes to the development of depressive disorders via epigenetic alterations. In particular, we focus on how microbiota-derived metabolites such as butyrate as an epigenetic modifier, probiotics, maternal diet, polyphenols, drugs (e.g., antipsychotics, antidepressants, and antibiotics), and fecal microbiota transplantation could positively alleviate depressive-like behaviors by modulating the epigenetic landscape. Finally, we will discuss challenges associated with recent therapeutic approaches for depressive disorders via microbiome-related epigenetic shifts, as well as opportunities to tackle such problems.
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Affiliation(s)
- Shabnam Nohesara
- Department of Medicine (Biomedical Genetics), Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA;
| | - Hamid Mostafavi Abdolmaleky
- Nutrition/Metabolism Laboratory, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boson, MA 02215, USA;
| | - Jin-Rong Zhou
- Nutrition/Metabolism Laboratory, Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boson, MA 02215, USA;
| | - Sam Thiagalingam
- Department of Medicine (Biomedical Genetics), Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA;
- Department of Pathology & Laboratory Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
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