1
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She MP, Hsieh YT, Lin LY, Tu CH, Wu MS, Hsin LW, Yu LCH. Differential roles of serotonin receptor subtypes in regulation of neurotrophin receptor expression and intestinal hypernociception. Histol Histopathol 2024; 39:903-919. [PMID: 38108436 DOI: 10.14670/hh-18-687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
OBJECTIVES Aberrant serotonin (5-hydroxytryptamine, 5-HT) metabolism and neurite outgrowth were associated with abdominal pain in irritable bowel syndrome (IBS). We previously demonstrated that 5-HT receptor subtype 7 (5-HT₇) was involved in visceral hypersensitivity of IBS-like mouse models. The aim was to compare the analgesic effects of a novel 5-HT₇ antagonist to reference standards in mouse models and investigate the mechanisms of 5-HT₇-dependent neuroplasticity. METHODS Two mouse models, including Giardia post-infection combined with water avoidance stress (GW) and post-resolution of trinitrobenzene sulfonic acid-induced colitis (PT) were used. Mice were orally administered CYY1005 (CYY, a novel 5-HT₇ antagonist), alosetron (ALN, a 5-HT₃ antagonist), and loperamide (LPM, an opioid receptor agonist) prior to measurement of visceromotor responses (VMR). Levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin receptors (NTRs) were assessed. RESULTS Peroral CYY was more potent than ALN or LPM in reducing VMR values in GW and PT mice. Increased mucosal 5-HT₇-expressing nerve fibers were associated with elevated Gap43 levels in the mouse colon. We observed higher colonic Ntrk2 and Ngfr expression in GW mice, and increased Bdnf expression in PT mice compared with control mice. Human SH-SY5Y cells stimulated with mouse colonic supernatant or exogenous serotonin exhibited longer nerve fibers, which CYY dose-dependently inhibited. Serotonin increased Ntrk1 and Ngfr expression via 5-HT₇ but not 5-HT₃ or 5-HT₄, while Ntrk2 upregulation was dependent on all three 5-HT receptor subtypes. CONCLUSIONS Stronger analgesic effects by peroral CYY were observed compared with reference standards in two IBS-like mouse models. The 5-HT₇-dependent NTR upregulation and neurite elongation may be involved in intestinal hypernociception.
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Affiliation(s)
- Meng-Ping She
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Yu-Ting Hsieh
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Li-Yu Lin
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Chia-Hung Tu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Ming-Shiang Wu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Ling-Wei Hsin
- School of Pharmacy, National Taiwan University, Taipei, Taiwan ROC
- Center for Innovative Therapeutics Discovery, National Taiwan University, Taipei, Taiwan ROC
| | - Linda Chia-Hui Yu
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC.
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2
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Dey P. Good girl goes bad: Understanding how gut commensals cause disease. Microb Pathog 2024; 190:106617. [PMID: 38492827 DOI: 10.1016/j.micpath.2024.106617] [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: 12/23/2023] [Revised: 03/09/2024] [Accepted: 03/10/2024] [Indexed: 03/18/2024]
Abstract
This review examines the complex connection between commensal microbiota and the development of opportunistic infections. Several underlying conditions, such as metabolic diseases and weakened immune systems, increase the vulnerability of patients to opportunistic infections. The increasing antibiotic resistance adds significant complexity to the management of infectious diseases. Although commensals have long been considered beneficial, recent research contradicts this notion by uncovering chronic illnesses linked to atypical pathogens or commensal bacteria. This review examines conditions in which commensal bacteria, which are usually beneficial, contribute to developing diseases. Commensals' support for opportunistic infections can be categorized based on factors such as colonization fitness, pathoadaptive mutation, and evasion of host immune response. Individuals with weakened immune systems are especially susceptible, highlighting the importance of mucosal host-microbiota interaction in promoting infection when conditions are inappropriate. Dysregulation of gut microbial homeostasis, immunological modulation, and microbial interactions are caused by several factors that contribute to the development of chronic illnesses. Knowledge about these mechanisms is essential for developing preventive measures, particularly for susceptible populations, and emphasizes the importance of maintaining a balanced gut microbiota in reducing the impact of opportunistic infections.
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Affiliation(s)
- Priyankar Dey
- Department of Biotechnology, Thapar Institute of Engineering and Technology, Patiala 147004, Punjab, India.
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3
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Zhang Z, Li D, Xie F, Muhetaer G, Zhang H. The cause-and-effect relationship between gut microbiota abundance and carcinoid syndrome: a bidirectional Mendelian randomization study. Front Microbiol 2023; 14:1291699. [PMID: 38188562 PMCID: PMC10766758 DOI: 10.3389/fmicb.2023.1291699] [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: 09/10/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024] Open
Abstract
Objective Carcinoid syndrome (CS) commonly results from neuroendocrine tumors. While active substances are recognized as the main causes of the typical symptoms such as diarrhea and skin flush, the cause-and-effect relationship between gut microbiota abundance and CS remains unclear. Methods The Single Nucleotide Polymorphisms (SNPs) related to gut microbiota abundance and CS were obtained from the GWAS summary data. The inverse variance weighted (IVW) method was used to assess the causal relationship between gut microbiota abundance and CS. Additionally, the MR-Egger, Weighted Median model, and Weighted model were employed as supplementary approaches. The heterogeneity function of the TwoSampleMR package was utilized to assess whether SNPs exhibit heterogeneity. The Egger intercept and Presso test were used to assess whether SNPs exhibit pleiotropy. The Leave-One-Out test was employed to evaluate the sensitivity of SNPs. The Steiger test was utilized to examine whether SNPs have a reverse causal relationship. A bidirectional mendelian randomization (MR) study was conducted to elucidate the inferred cause-and-effect relationship between gut microbiota abundance and CS. Results The IVW results indicated a causal relationship between 6 gut microbiota taxa and CS. Among the 6 gut microbiota taxa, the genus Anaerofilum (IVW OR: 0.3606, 95%CI: 0.1554-0.8367, p-value: 0.0175) exhibited a protective effect against CS. On the other hand, the family Coriobacteriaceae (IVW OR: 3.4572, 95%CI: 1.0571-11.3066, p-value: 0.0402), the genus Enterorhabdus (IVW OR: 4.2496, 95%CI: 1.3314-13.5640, p-value: 0.0146), the genus Ruminiclostridium6 (IVW OR: 4.0116, 95%CI: 1.2711-12.6604, p-value: 0.0178), the genus Veillonella (IVW OR: 3.7023, 95%CI: 1.0155-13.4980, p-value: 0.0473) and genus Holdemanella (IVW OR: 2.2400, 95%CI: 1.0376-4.8358, p-value: 0.0400) demonstrated a detrimental effect on CS. The CS was not found to have a reverse causal relationship with the above 6 gut microbiota taxa. Conclusion Six microbiota taxa were found to have a causal relationship with CS, and further randomized controlled trials are needed for verification.
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Affiliation(s)
- Zexin Zhang
- The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Dongting Li
- The Affiliated Guangzhou Hospital of TCM of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Fengxi Xie
- Maoming Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Gulizeba Muhetaer
- The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Haibo Zhang
- The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
- Guangdong Key Laboratory of Clinical Research of Chinese Medicine, Guangzhou, China
- Guangdong Joint Laboratory of Guangdong, Hong Kong and Macao Chinese Medicine and Immune Diseases, Guangzhou, China
- State Key Laboratory of Wet Certificate of Chinese Medicine Jointly Built by the Province and the Ministry, Guangzhou, China
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4
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McGregor BA, Razmjou E, Hooshyar H, Seeger DR, Golovko SA, Golovko MY, Singer SM, Hur J, Solaymani-Mohammadi S. A shotgun metagenomic analysis of the fecal microbiome in humans infected with Giardia duodenalis. Parasit Vectors 2023; 16:239. [PMID: 37464386 PMCID: PMC10354925 DOI: 10.1186/s13071-023-05821-1] [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: 04/10/2023] [Accepted: 05/28/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND The mechanisms underlying the clinical outcome disparity during human infection with Giardia duodenalis are still unclear. In recent years, evidence has pointed to the roles of host factors as well as parasite's genetic heterogeneity as major contributing factors in the development of symptomatic human giardiasis. However, it remains contested as to how only a small fraction of individuals infected with G. duodenalis develop clinical gastrointestinal manifestations, whereas the majority of infected individuals remain asymptomatic. Here, we demonstrate that diversity in the fecal microbiome correlates with the clinical outcome of human giardiasis. METHODS The genetic heterogeneity of G. duodenalis clinical isolates from human subjects with asymptomatic and symptomatic giardiasis was determined using a multilocus analysis approach. We also assessed the genetic proximity of G. duodenalis isolates by constructing phylogenetic trees using the maximum likelihood. Total genomic DNA (gDNA) from fecal specimens was utilized to construct DNA libraries, followed by performing paired-end sequencing using the HiSeq X platform. The Kraken2-generated, filtered FASTQ files were assigned to microbial metabolic pathways and functions using HUMAnN 3.04 and the UniRef90 diamond annotated full reference database (version 201901b). Results from HUMAnN for each sample were evaluated for differences among the biological groups using the Kruskal-Wallis non-parametric test with a post hoc Dunn test. RESULTS We found that a total of 8/11 (72.73%) human subjects were infected with assemblage A (sub-assemblage AII) of G. duodenalis, whereas 3/11 (27.27%) human subjects in the current study were infected with assemblage B of the parasite. We also found that the parasite's genetic diversity was not associated with the clinical outcome of the infection. Further phylogenetic analysis based on the tpi and gdh loci indicated that those clinical isolates belonging to assemblage A of G. duodenalis subjects clustered compactly together in a monophyletic clade despite being isolated from human subjects with asymptomatic and symptomatic human giardiasis. Using a metagenomic shotgun sequencing approach, we observed that infected individuals with asymptomatic and symptomatic giardiasis represented distinctive microbial diversity profiles, and that both were distinguishable from the profiles of healthy volunteers. CONCLUSIONS These findings identify a potential association between host microbiome disparity with the development of clinical disease during human giardiasis, and may provide insights into the mechanisms by which the parasite induces pathological changes in the gut. These observations may also lead to the development of novel selective therapeutic targets for preventing human enteric microbial infections.
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Affiliation(s)
- Brett A. McGregor
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
| | - Elham Razmjou
- Department of Parasitology and Mycology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Hossein Hooshyar
- Department of Medical Parasitology and Mycology, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran
| | - Drew R. Seeger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
| | - Svetlana A. Golovko
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
| | - Mikhail Y. Golovko
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
| | - Steven M. Singer
- Department of Biology, Georgetown University, Washington, DC USA
| | - Junguk Hur
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
| | - Shahram Solaymani-Mohammadi
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
- Laboratory of Mucosal Immunology, Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND USA
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5
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Giallourou N, Arnold J, McQuade ETR, Awoniyi M, Becket RVT, Walsh K, Herzog J, Gulati AS, Carroll IM, Montgomery S, Quintela PH, Faust AM, Singer SM, Fodor AA, Ahmad T, Mahfuz M, Mduma E, Walongo T, Guerrant RL, Balfour Sartor R, Swann JR, Kosek MN, Bartelt LA. Giardia hinders growth by disrupting nutrient metabolism independent of inflammatory enteropathy. Nat Commun 2023; 14:2840. [PMID: 37202423 PMCID: PMC10195804 DOI: 10.1038/s41467-023-38363-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 04/27/2023] [Indexed: 05/20/2023] Open
Abstract
Giardia lamblia (Giardia) is among the most common intestinal pathogens in children in low- and middle-income countries (LMICs). Although Giardia associates with early-life linear growth restriction, mechanistic explanations for Giardia-associated growth impairments remain elusive. Unlike other intestinal pathogens associated with constrained linear growth that cause intestinal or systemic inflammation or both, Giardia seldom associates with chronic inflammation in these children. Here we leverage the MAL-ED longitudinal birth cohort and a model of Giardia mono-association in gnotobiotic and immunodeficient mice to propose an alternative pathogenesis of this parasite. In children, Giardia results in linear growth deficits and gut permeability that are dose-dependent and independent of intestinal markers of inflammation. The estimates of these findings vary between children in different MAL-ED sites. In a representative site, where Giardia associates with growth restriction, infected children demonstrate broad amino acid deficiencies, and overproduction of specific phenolic acids, byproducts of intestinal bacterial amino acid metabolism. Gnotobiotic mice require specific nutritional and environmental conditions to recapitulate these findings, and immunodeficient mice confirm a pathway independent of chronic T/B cell inflammation. Taken together, we propose a new paradigm that Giardia-mediated growth faltering is contingent upon a convergence of this intestinal protozoa with nutritional and intestinal bacterial factors.
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Affiliation(s)
- Natasa Giallourou
- Division of Digestive Diseases, Department of Metabolism, Digestion, and Reproduction, Faculty of Medicine, Imperial College London, London, UK.
- Centre of Excellence in Biobanking and Biomedical Research, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus.
| | - Jason Arnold
- Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Molecular Genetics and Microbiology, Duke Microbiome Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | | | - Muyiwa Awoniyi
- Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rose Viguna Thomas Becket
- Departments of Pediatrics and Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kenneth Walsh
- Institute for Infectious Diseases and Global Health and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeremy Herzog
- Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ajay S Gulati
- Departments of Pediatrics and Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ian M Carroll
- Department of Nutrition, Gillings School of Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Stephanie Montgomery
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | | | | | - Steven M Singer
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Anthony A Fodor
- The University of North Carolina Charlotte, Department of Bioinformatics and Genomics, Charlotte, USA
| | - Tahmeed Ahmad
- International Center for Diarrheal Disease Research, Dhaka, Bangladesh
| | - Mustafa Mahfuz
- International Center for Diarrheal Disease Research, Dhaka, Bangladesh
| | - Esto Mduma
- Haydom Global Health Research Centre, Haydom Lutheran Hospital, Haydom, Tanzania
| | - Thomas Walongo
- Haydom Global Health Research Centre, Haydom Lutheran Hospital, Haydom, Tanzania
| | - Richard L Guerrant
- Division of Infectious Diseases and International Health, Department of Medicine, The University of Virginia Charlottesville, Charlottesville, VA, USA
| | - R Balfour Sartor
- Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jonathan R Swann
- School of Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Margaret N Kosek
- Division of Infectious Diseases and International Health, Department of Medicine, The University of Virginia Charlottesville, Charlottesville, VA, USA
| | - Luther A Bartelt
- Center for Gastrointestinal Biology and Disease, Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Institute for Infectious Diseases and Global Health and the Division of Infectious Diseases, Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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6
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Buret AG, Allain T. Gut microbiota biofilms: From regulatory mechanisms to therapeutic targets. J Exp Med 2023; 220:e20221743. [PMID: 36688957 PMCID: PMC9884580 DOI: 10.1084/jem.20221743] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Gut microbiota contain communities of viruses, bacteria, fungi, and Eukarya, and live as biofilms. In health, these biofilms adhere to the intestinal mucus surface without contacting the epithelium. Disruptions to the equilibrium between these biofilms and the host may create invasive pathobionts from these commensal communities and contribute to disease pathogenesis. Environmental factors appear to dominate over genetics in determining the shifts in microbiota populations and function, including when comparing microbiota between low-income and industrialized countries. The observations discussed herein carry enormous potential for the development of novel therapies targeting phenotype in microbiota dysbiosis.
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Affiliation(s)
- Andre G. Buret
- Department of Biological Sciences, Host-Parasite Interactions program, Inflammation Research Network, University of Calgary, Calgary, Canada
| | - Thibault Allain
- Department of Biological Sciences, Host-Parasite Interactions program, Inflammation Research Network, University of Calgary, Calgary, Canada
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7
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Pessarelli T, Basilisco G, Spina L, Fraquelli M. Intestinal pseudo-obstruction caused by Giardia lambliainfection. BMJ Case Rep 2022; 15:15/11/e252319. [DOI: 10.1136/bcr-2022-252319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A woman in her 40s presented with malaise, nausea, reduced appetite, abdominal distention, loose stools and weight loss. Symptoms had started 6 months earlier and worsened in the last 2 weeks. CT enterography showed hypotonic dilated small bowel loops in absence of any mechanical obstruction. Endoscopic examinations including capsule endoscopy did not reveal any obstructing lesion, but a delayed small bowel transit time of the capsule. Duodenal histology revealed Marsh 3a villous atrophy. Secondary causes of intestinal pseudo-obstruction and villous atrophy were investigated.Giardia lambliatrophozoites were found in the stools and in the duodenal biopsies. The patient’s symptoms quickly resolved after metronidazole treatment with complete normalisation of duodenal histology.
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8
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Dougherty M, Bartelt LA. Giardia and growth impairment in children in high-prevalence settings: consequence or co-incidence? Curr Opin Infect Dis 2022; 35:417-423. [PMID: 35980005 PMCID: PMC10373467 DOI: 10.1097/qco.0000000000000877] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
PURPOSE OF REVIEW Giardia is a common intestinal parasite worldwide, and infection can be associated with clear, and sometimes persistent symptomatology. However, in children in high-prevalence settings, it is most often not associated with or is perhaps even protective against acute diarrhea. Nonetheless, recent longitudinal studies in high-prevalence settings increasingly identify an association with long-term outcomes that has been difficult to discern. RECENT FINDINGS Recent studies have made progress in disentangling this apparent paradox. First, prospective, well characterized cohort studies have repeatedly identified associations between Giardia infection, gut function, and child growth. Second, experimental animal and in-vitro models have further characterized the biological plausibility that Giardia could impair intestinal function and subsequently child development through different pathways, depending upon biological and environmental factors. Finally, new work has shed light on the potential for Giardia conspiring with specific other gut microbes, which may explain discrepant findings in the literature, help guide future higher resolution analyses of this pathogen, and inform new opportunities for intervention. SUMMARY Recent prospective studies have confirmed a high, if not universal, prevalence of persistent Giardia infections in low-and-middle income countries associated with child-growth shortfalls and altered gut permeability. However, the predominance of subclinical infections limits understanding of the true clinical impact of endemic pediatric giardiasis, and global disease burdens remain uncalculated. Integrating the role of Giardia in multipathogen enteropathies and how nutritional, microbial, metabolic, and pathogen-strain variables influence Giardia infection outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite.
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Affiliation(s)
- Michael Dougherty
- Division of Gastroenterology and Hepatology, Department of Medicine, University of North Carolina at Chapel Hill
- Rex Digestive Healthcare, UNC REX Healthcare, Raleigh
| | - Luther A. Bartelt
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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9
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Garrigues Q, Apper E, Chastant S, Mila H. Gut microbiota development in the growing dog: A dynamic process influenced by maternal, environmental and host factors. Front Vet Sci 2022; 9:964649. [PMID: 36118341 PMCID: PMC9478664 DOI: 10.3389/fvets.2022.964649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/12/2022] [Indexed: 11/13/2022] Open
Abstract
Microorganisms of the gastrointestinal tract play a crucial role in the health, metabolism and development of their host by modulating vital functions such as digestion, production of key metabolites or stimulation of the immune system. This review aims to provide an overview on the current knowledge of factors shaping the gut microbiota of young dogs. The composition of the gut microbiota is modulated by many intrinsic (i.e., age, physiology, pathology) and extrinsic factors (i.e., nutrition, environment, medication) which can cause both beneficial and harmful effects depending on the nature of the changes. The composition of the gut microbiota is quickly evolving during the early development of the dog, and some crucial bacteria, mostly anaerobic, progressively colonize the gut before the puppy reaches adulthood. Those bacterial communities are of paramount importance for the host health, with disturbance in their composition potentially leading to altered metabolic states such as acute diarrhea or inflammatory bowel disease. While many studies focused on the microbiota of young children, there is still a lack of knowledge concerning the development of gut microbiota in puppies. Understanding this early evolution is becoming a key aspect to improve dogs' short and long-term health and wellbeing.
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Affiliation(s)
- Quentin Garrigues
- NeoCare, ENVT, Université de Toulouse, Toulouse, France
- *Correspondence: Quentin Garrigues
| | | | | | - Hanna Mila
- NeoCare, ENVT, Université de Toulouse, Toulouse, France
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10
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Chang WY, Yang YT, She MP, Tu CH, Lee TC, Wu MS, Sun CH, Hsin LW, Yu LCH. 5-HT 7 receptor-dependent intestinal neurite outgrowth contributes to visceral hypersensitivity in irritable bowel syndrome. J Transl Med 2022; 102:1023-1037. [PMID: 36775417 PMCID: PMC9420680 DOI: 10.1038/s41374-022-00800-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 04/22/2022] [Accepted: 04/22/2022] [Indexed: 12/19/2022] Open
Abstract
Irritable bowel syndrome (IBS) is characterized by visceral hypersensitivity (VH) associated with abnormal serotonin/5-hydroxytryptamine (5-HT) metabolism and neurotrophin-dependent mucosal neurite outgrowth. The underlying mechanisms of VH remain poorly understood. We investigated the role of 5-HT7 receptor in mucosal innervation and intestinal hyperalgesia. A high density of mucosal nerve fibres stained for 5-HT7 was observed in colonoscopic biopsy specimens from IBS patients compared with those from healthy controls. Staining of 5-HT3 and 5-HT4 receptors was observed mainly in colonic epithelia with comparable levels between IBS and controls. Visceromotor responses to colorectal distension were evaluated in two mouse models, one postinfectious with Giardia and subjected to water avoidance stress (GW) and the other postinflammatory with trinitrobenzene sulfonic acid-induced colitis (PT). Increased VH was associated with higher mucosal density of 5-HT7-expressing nerve fibres and elevated neurotrophin and neurotrophin receptor levels in the GW and PT mice. The increased VH was inhibited by intraperitoneal injection of SB-269970 (a selective 5-HT7 antagonist). Peroral multiple doses of CYY1005 (a novel 5-HT7 ligand) decreased VH and reduced mucosal density of 5-HT7-expressing nerve fibres in mouse colon. Human neuroblastoma SH-SY5Y cells incubated with bacteria-free mouse colonic supernatant, 5-HT, nerve growth factor, or brain-derived neurotrophic factor exhibited nerve fibre elongation, which was inhibited by 5-HT7 antagonists. Gene silencing of HTR7 also reduced the nerve fibre length. Activation of 5-HT7 upregulated NGF and BDNF gene expression, while stimulation with neurotrophins increased the levels of tryptophan hydroxylase 2 and 5-HT7 in neurons. A positive-feedback loop was observed between serotonin and neurotrophin pathways via 5-HT7 activation to aggravate fibre elongation, whereby 5-HT3 and 5-HT4 had no roles. In conclusion, 5-HT7-dependent mucosal neurite outgrowth contributed to VH. A novel 5-HT7 antagonist could be used as peroral analgesics for IBS-related pain.
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Affiliation(s)
- Wen-Ying Chang
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Yi-Ting Yang
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Meng-Ping She
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Chia-Hung Tu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Tsung-Chun Lee
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Ming-Shiang Wu
- Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan ROC
| | - Chin-Hung Sun
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan ROC
| | - Ling-Wei Hsin
- Graduate Institute of Pharmacy, National Taiwan University School of Pharmacy, Taipei, Taiwan ROC.
- Center for Innovative Therapeutics Discovery, National Taiwan University, Taipei, Taiwan ROC.
| | - Linda Chia-Hui Yu
- Graduate Institute of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan ROC.
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11
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Souza JB, Tsantarlis K, Tonelli RR. Oxygen-dependent regulation of permeability in low resistance intestinal epithelial cells infected with Giardia lamblia. Exp Parasitol 2022; 240:108329. [PMID: 35868574 DOI: 10.1016/j.exppara.2022.108329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 06/22/2022] [Accepted: 07/11/2022] [Indexed: 11/26/2022]
Abstract
Intestinal epithelial cells (IECs) reside in a highly anaerobic environment that is subject to daily fluctuations in partial oxygen pressure (pO2), depending on intestinal tissue perfusion. This condition, known as physiological hypoxia, has a major impact on the maintenance of gut homeostasis, such as effects on the integrity and function of the intestinal epithelial barrier. Giardia lamblia is a microaerophilic protozoan parasite that infects and colonizes the small intestine of its host, causing watery diarrhea. The disease, known as giardiasis, is associated with enhanced intestinal permeability and disruption or reorganization of tight junction (TJ) proteins between IECs. Given the central role of oxygen in gut homeostasis, in this study, we aimed to evaluate whether pO2 affects intestinal permeability (flux of ions and macromolecules) and TJ protein expression in human IECs during G. lamblia infection. Using human cell lines HuTu-80 and Caco-2 as models of "loose" (low resistance) and "tight" (high resistance) intestines, respectively, we elucidated that low pO2 drives intestinal barrier dysfunction in IECs infected with trophozoites through dephosphorylation of protein kinase C (PKC α/β II). Additionally, we demonstrated that IECs infected with trophozoites in the presence of a pharmacological PKC activator (phorbol 12-myristate 13-acetate) partially restored the barrier function, which was correlated with increased protein expression levels of zonula occludens (ZO)-2 and occludin. Collectively, these results support the emerging theory that molecular oxygen impacts gut homeostasis during Giardia infection via direct host signaling pathways. These findings further our knowledge regarding Giardia-host interactions and the pathophysiological mechanisms of human giardiasis.
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Affiliation(s)
- Juliana Bizarri Souza
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, 04023-062, São Paulo, SP, Brazil
| | - Katherine Tsantarlis
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, 04023-062, São Paulo, SP, Brazil
| | - Renata Rosito Tonelli
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, 04023-062, São Paulo, SP, Brazil; Departamento de Ciências Farmacêuticas, Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, 09913-030, Diadema, SP, Brazil.
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12
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Savarino E, Zingone F, Barberio B, Marasco G, Akyuz F, Akpinar H, Barboi O, Bodini G, Bor S, Chiarioni G, Cristian G, Corsetti M, Di Sabatino A, Dimitriu AM, Drug V, Dumitrascu DL, Ford AC, Hauser G, Nakov R, Patel N, Pohl D, Sfarti C, Serra J, Simrén M, Suciu A, Tack J, Toruner M, Walters J, Cremon C, Barbara G. Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility. United European Gastroenterol J 2022; 10:556-584. [PMID: 35695704 PMCID: PMC9278595 DOI: 10.1002/ueg2.12259] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/20/2022] [Indexed: 11/23/2022] Open
Abstract
Irritable bowel syndrome with diarrhoea (IBS‐D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS‐D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work‐up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS‐D and FDr. In terms of diagnosis, the consensus supports a symptom‐based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C‐reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo‐, di‐, monosaccharides and polyols, gut‐directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5‐hydroxytryptamine‐3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS‐D and FDr.
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Affiliation(s)
- Edoardo Savarino
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Fabiana Zingone
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Brigida Barberio
- Gastroenterology Unit, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy
| | - Giovanni Marasco
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Filiz Akyuz
- Department of Gastroenterology, İstanbul University İstanbul School of Medicine, İstanbul, Turkey
| | - Hale Akpinar
- Department of Internal Medicine, Dokuz Eylül University School of Medicine, Izmir, Turkey
| | - Oana Barboi
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Giorgia Bodini
- Gastrointestinal Unit, Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Serhat Bor
- Division of Gastroenterology, Ege University School of Medicine, Izmir, Turkey
| | | | - Gheorghe Cristian
- Fundeni Clinical Institute Center of Gastroenterology and Hepatology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Maura Corsetti
- National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK.,Nottingham Digestive Diseases Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Antonio Di Sabatino
- First Department of Internal Medicine, IRCCS San Matteo Hospital Foundation, University of Pavia, Pavia, Italy
| | - Anca Mirela Dimitriu
- Center of Gastroenterology and Hepatology, Fundeni Clinical Institute, University of Medicine and Pharmacy, Bucharest, Romania
| | - Vasile Drug
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Dan L Dumitrascu
- 2nd Department of Internal Medicine, 'Iuliu Hatieganu' University of Medicine and Farmacy, Cluj-Napoca, Romania
| | - Alexander C Ford
- Leeds Gastroenterology Institute, Leeds Teaching Hospitals NHS Trust, Leeds, UK.,Leeds Institute of Medical Research at St. James's Sciences, University of Leeds, Leeds, UK
| | - Goran Hauser
- Department of Gastroenterology, Clinical Hospital Center Rijeka, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Radislav Nakov
- Department of Gastroenterology, Tsaritsa Yoanna University Hospital, Medical University of Sofia, Sofia, Bulgaria
| | - Nisha Patel
- Imperial College Healthcare NHS Trust, Institute of Global Health Innovation, St Mary's Hospital Campus, London, UK
| | - Daniel Pohl
- Department of Gastroenterology, University Hospital Zurich, Zurich, Switzerland
| | - Cătălin Sfarti
- Department of Gastroenterology, 'Grigore T. Popa' University of Medicine and Pharmacy, Iasi, Romania.,Institute of Gastroenterology and Hepatology, 'Saint Spiridon' Hospital, Iasi, Romania
| | - Jordi Serra
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Badalona, Spain.,Digestive System Research Unit, University Hospital Vall d'Hebron, Barcelona, Spain.,Department of Medicine, Autonomous University of Barcelona, Badalona, Spain
| | - Magnus Simrén
- Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Alina Suciu
- Center of Gastroenterology and Hepatology, Fundeni Clinical Institute, University of Medicine and Pharmacy, Bucharest, Romania
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Murat Toruner
- Department of Gastroenterology, Ankara University School of Medicine, Ankara, Turkey
| | - Julian Walters
- Division of Digestive Diseases, Department of Metabolism, Digestion, and Reproduction, Faculty of Medicine, Imperial College London, London, UK.,Department of Gastroenterology, Division of Medicine and Integrated Care, Imperial College Healthcare NHS Trust, London, UK
| | - Cesare Cremon
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Giovanni Barbara
- Division of Internal Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.,Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
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13
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Solaymani-Mohammadi S. Mucosal Defense Against Giardia at the Intestinal Epithelial Cell Interface. Front Immunol 2022; 13:817468. [PMID: 35250996 PMCID: PMC8891505 DOI: 10.3389/fimmu.2022.817468] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/31/2022] [Indexed: 02/05/2023] Open
Abstract
Human giardiasis, caused by the protozoan parasite Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis, Lamblia intestinalis), is one of the most commonly-identified parasitic diseases worldwide. Chronic G. duodenalis infections cause a malabsorption syndrome that may lead to failure to thrive and/or stunted growth, especially in children in developing countries. Understanding the parasite/epithelial cell crosstalk at the mucosal surfaces of the small intestine during human giardiasis may provide novel insights into the mechanisms underlying the parasite-induced immunopathology and epithelial tissue damage, leading to malnutrition. Efforts to identify new targets for intervening in the development of intestinal immunopathology and the progression to malnutrition are critical. Translating these findings into a clinical setting will require analysis of these pathways in cells and tissues from humans and clinical trials could be devised to determine whether interfering with unwanted mucosal immune responses developed during human giardiasis provide better therapeutic benefits and clinical outcomes for G. duodenalis infections in humans.
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Affiliation(s)
- Shahram Solaymani-Mohammadi
- Laboratory of Mucosal Immunology, Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
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14
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Abedi SH, Fazlzadeh A, Mollalo A, Sartip B, Mahjour S, Bahadory S, Taghipour A, Rostami A. The neglected role of Blastocystis sp. and Giardia lamblia in development of irritable bowel syndrome: A systematic review and meta-analysis. Microb Pathog 2021; 162:105215. [PMID: 34592369 DOI: 10.1016/j.micpath.2021.105215] [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: 06/14/2021] [Revised: 09/22/2021] [Accepted: 09/25/2021] [Indexed: 02/08/2023]
Abstract
The possible role of Blastocystis sp. and Giardia lamblia infections in the development of irritable bowel syndrome (IBS) has long been controversial. In this study, we conducted a systematic review and meta-analysis to investigate whether these protozoan infections are associated with IBS development. We systematically searched international databases for all studies that reported these protozoa in IBS patients published by May 10, 2021. Studies were included in the review if they were observational studies with confirmed patients with IBS (in case-control and cross-sectional studies) or parasitic infections (cohort studies) with an appropriate control group. Pooled odds ratios (ORs) and 95% confidence intervals were estimated using a random-effects meta-analysis model for included studies. A total of 32 papers (42 datasets), including 29 papers (31 datasets) for Blastocystis sp./IBS and 11 papers (11 datasets) for G. lamblia/IBS met the eligibility criteria. Our results indicated that the individuals with Blastocystis sp. infection were significantly at a higher risk of IBS development (OR, 1.78; 95%CI, 1.29-2.44). Moreover, cohort studies indicated a significant positive association between G. lamblia infection and IBS risk (OR, 5.47; 95%CI, 4.23-7.08); while an increasing but no statistically significant risk was observed in case-control studies (OR, 1.19; 95%CI, 0.75-1.87). Our findings suggested that Blastocystis sp. and G. lamblia infections are associated with the increased risk of developing IBS. Despite these results, further studies are needed to determine the effect of these protozoa on IBS development.
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Affiliation(s)
- Seyed Hasan Abedi
- Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Aylar Fazlzadeh
- Department of Internal Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolfazl Mollalo
- Department of Public Health and Prevention Science, School of Health Sciences, Baldwin Wallace University, Berea, OH, USA
| | - Behnam Sartip
- Department of Internal Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Sanaz Mahjour
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Saeed Bahadory
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Taghipour
- Zoonoses Research Center, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
| | - Ali Rostami
- Infectious Diseases and Tropical Medicine Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran.
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15
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High-fat diet increases the severity of Giardia infection in association with low-grade inflammation and gut microbiota dysbiosis. Sci Rep 2021; 11:18842. [PMID: 34552170 PMCID: PMC8458452 DOI: 10.1038/s41598-021-98262-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/01/2021] [Indexed: 12/26/2022] Open
Abstract
Exogenous factors that may influence the pathophysiology of Giardia infection remain incompletely understood. We have investigated the role of dietary fat in the pathogenesis of Giardia infection. Male 3 to 4-week-old C57BL/6 mice were fed either a low fat (LF) or a high fat (HF) diet for 12 days and challenged with G. duodenalis. In infected animals, the trophozoite burden was higher in HF + Giardia mice compared to the LF + Giardia group at day 7 post infection. Fatty acids exerted direct pro-growth effects on Giardia trophozoites. Analysis of disease parameters showed that HF + Giardia mice exhibited more mucosal infiltration by inflammatory cells, decreased villus/crypt ratios, goblet cell hyperplasia, mucus disruption, increased gut motility, and elevated fecal water content compared with LF + Giardia. HF diet-dependent exacerbation of Giardia-induced goblet cell hyperplasia was associated with elevated Atoh1 and Muc2 gene expression. Gut microbiota analysis revealed that the HF diet alone induces a taxonomic shift. HF + Giardia mice exhibited microbiota dysbiosis characterized by an increase of Firmicutes and a decrease of Bacteroidetes and significant changes in α- and β-diversity metrics. Taken together, the findings suggest that a HF diet exacerbates the outcome of Giardia infection. The data demonstrate that elevated dietary fat represents an important exogenous factor promoting the pathophysiology of giardiasis.
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16
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Rajeev S, Sosnowski O, Li S, Allain T, Buret AG, McKay DM. Enteric Tuft Cells in Host-Parasite Interactions. Pathogens 2021; 10:pathogens10091163. [PMID: 34578195 PMCID: PMC8467374 DOI: 10.3390/pathogens10091163] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 11/16/2022] Open
Abstract
Enteric tuft cells are chemosensory epithelial cells gaining attention in the field of host-parasite interactions. Expressing a repertoire of chemosensing receptors and mediators, these cells have the potential to detect lumen-dwelling helminth and protozoan parasites and coordinate epithelial, immune, and neuronal cell defenses against them. This review highlights the versatility of enteric tuft cells and sub-types thereof, showcasing nuances of tuft cell responses to different parasites, with a focus on helminths reflecting the current state of the field. The role of enteric tuft cells in irritable bowel syndrome, inflammatory bowel disease and intestinal viral infection is assessed in the context of concomitant infection with parasites. Finally, the review presents pertinent questions germane to understanding the enteric tuft cell and its role in enteric parasitic infections. There is much to be done to fully elucidate the response of this intriguing cell type to parasitic-infection and there is negligible data on the biology of the human enteric tuft cell—a glaring gap in knowledge that must be filled.
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Affiliation(s)
- Sruthi Rajeev
- Gastrointestinal Research Group, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.R.); (S.L.)
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
| | - Olivia Sosnowski
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Shuhua Li
- Gastrointestinal Research Group, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.R.); (S.L.)
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
| | - Thibault Allain
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - André G. Buret
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Derek M. McKay
- Gastrointestinal Research Group, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.R.); (S.L.)
- Inflammation Research Network and Host-Parasite Interaction Group, University of Calgary, Calgary, AB T2N 4N1, Canada; (O.S.); (T.A.); (A.G.B.)
- Correspondence: ; Tel.: +1-403-220-7362
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17
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Age and Giardia intestinalis Infection Impact Canine Gut Microbiota. Microorganisms 2021; 9:microorganisms9091862. [PMID: 34576757 PMCID: PMC8469385 DOI: 10.3390/microorganisms9091862] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/16/2022] Open
Abstract
Giardia intestinalis is a flagellated protozoan responsible for giardiosis (also called giardiasis in humans), the most prevalent and widespread parasitic infection in humans and mammals worldwide. The intestinal microbiota is highly diverse and any alteration in its composition may impact on the health of the host. While studies on the mouse model of giardiosis described the role of the gut microbiota in host susceptibility to infection by the parasite, little is known about the gut microbiota during natural infections in dogs and particularly in puppies. In this study, we monitored naturally G. intestinalis-infected puppies for 3 months and quantified cyst excretion every 2 weeks. All puppies remained subclinically infected during the sampling period as confirmed by fecal examination. In parallel, we performed 16S Illumina sequencing of fecal samples from the different time points to assess the impact of G. intestinalis infection on gut microbiota development of the puppies, as well as gut health markers of immunity such as fecal IgA and calprotectin. Sequencing results revealed that the canine fecal microbiota of Giardia-infected puppies becomes more complex and less diverse with increasing age. In addition, significant differences in the structure of the microbiota were observed between puppies with high and low Giardia cyst excretion. Chronic subclinical G. intestinalis infection appears to be associated with some detrimental structural changes in the gut microbiota. G. intestinalis-associated dysbiosis is characterized by an enrichment of facultative anaerobic, mucus-degrading, pro-inflammatory species and opportunistic pathogens, as well as a reduction of Lactobacillus johnsonii at specific time points. Calprotectin levels increased with age, suggesting the establishment of chronic low-grade inflammation in puppies. Further work is needed to demonstrate whether these alterations in the canine gut microbiota could lead to a dysbiosis-related disease, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).
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18
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Abstract
Giardia duodenalis captured the attention of Leeuwenhoek in 1681 while he was examining his own diarrheal stool, but, ironically, it did not really gain attention as a human pathogen until the 1960s, when outbreaks were reported. Key technological advances, including in vitro cultivation, genomic and proteomic databases, and advances in microscopic and molecular approaches, have led to an understanding that this is a eukaryotic organism with a reduced genome rather than a truly premitochondriate eukaryote. This has included the discovery of mitosomes (vestiges of mitochondria), a transport system with many of the features of the Golgi apparatus, and even evidence for a sexual or parasexual cycle. Cell biology approaches have led to a better understanding of how Giardia survives with two nuclei and how it goes through its life cycle as a noninvasive organism in the hostile environment of the lumen of the host intestine. Studies of its immunology and pathogenesis have moved past the general understanding of the importance of the antibody response in controlling infection to determining the key role of the Th17 response. This work has led to understanding of the requirement for a balanced host immune response that avoids the extremes of an excessive response with collateral damage or one that is unable to clear the organism. This understanding is especially important in view of the remarkable ranges of early manifestations, which range from asymptomatic to persistent diarrhea and weight loss, and longer-term sequelae that include growth stunting in children who had no obvious symptoms and a high frequency of postinfectious irritable bowel syndrome (IBS).
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19
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20
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Abstract
Epidemiologic data support that acute gastrointestinal infection is one of the strongest risk factors for development of irritable bowel syndrome (IBS). Risk of post-infection IBS (PI-IBS) seems to be greater with bacterial and protozoal than viral enterocolitis. Younger individuals, women, and those with severe enterocolitis are more likely to develop PI-IBS. Disease mechanisms in animal models and humans involve chronic perturbation of intestinal microbiome, epithelial and neuronal remodeling, and immune activation. These mechanisms can lead to luminal (increased proteolytic activity, altered bile acid composition) and physiologic (increased permeability, transit changes, and visceral hypersensitivity) alterations that can mediate PI-IBS symptoms.
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Affiliation(s)
- Antonio Berumen
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA
| | - Adam L Edwinson
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA
| | - Madhusudan Grover
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA; Department of Medicine and Physiology, Enteric NeuroScience Program, 200 First Street Southwest, Rochester, MN 55905, USA.
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21
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Cheng L, Luo QQ, Chen SL. The role of intestinal mast cell infiltration in irritable bowel syndrome. J Dig Dis 2021; 22:143-151. [PMID: 33511763 DOI: 10.1111/1751-2980.12971] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 01/17/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022]
Abstract
As an essential part of the immune system, mast cells (MCs) play an important role in the pathogenesis of irritable bowel syndrome (IBS). Accumulating evidence has identified altered MC count and density in intestinal mucosa of patients with IBS; however, conflicting findings yield inconsistent conclusions. Currently, most studies have suggested intestinal MC infiltration in IBS patients. Considering the pivotal role of MCs in IBS, it is necessary to achieve a better understanding about the pathological changes in the intestine. The risk factors for IBS, including dietary habits, psychological factors, infection, and dysbiosis, are implicated to induce intestinal MC infiltration. Mechanistically, food may trigger immune-related allergic reactions and affect the intestinal microbiota activity. Some exogenous pathogens and altered profile of commensal bacteria promote intestinal MC recruitment through promoted release of chemokines from epithelial cells or direct activation of the immune system. In addition, psychological factors may affect the microenvironment where MCs live. MCs have been proven to interact with the enteric neurons and other immunocytes, evidenced by the close proximity of MCs to neurons and regional altered immune system components. A variety of mediators released by the enteric neurons, immunocytes, and MCs per se, such as neurotrophins, neuropeptides, cytokines, and chemokines, may have stimulant effects on MCs by modulating the survival, proliferation, and recruitment process of MCs in the intestine. In this review, the associations between IBS and intestinal MC density and the underlying mechanisms are discussed.
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Affiliation(s)
- Li Cheng
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai, China
| | - Qing Qing Luo
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai, China
| | - Sheng Liang Chen
- Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Institute of Digestive Disease, Shanghai, China
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22
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Fekete E, Allain T, Siddiq A, Sosnowski O, Buret AG. Giardia spp. and the Gut Microbiota: Dangerous Liaisons. Front Microbiol 2021; 11:618106. [PMID: 33510729 PMCID: PMC7835142 DOI: 10.3389/fmicb.2020.618106] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/15/2020] [Indexed: 12/11/2022] Open
Abstract
Alteration of the intestinal microbiome by enteropathogens is commonly associated with gastrointestinal diseases and disorders and has far-reaching consequences for overall health. Significant advances have been made in understanding the role of microbial dysbiosis during intestinal infections, including infection with the protozoan parasite Giardia duodenalis, one of the most prevalent gut protozoa. Altered species composition and diversity, functional changes in the commensal microbiota, and changes to intestinal bacterial biofilm structure have all been demonstrated during the course of Giardia infection and have been implicated in Giardia pathogenesis. Conversely, the gut microbiota has been found to regulate parasite colonization and establishment and plays a critical role in immune modulation during mono and polymicrobial infections. These disruptions to the commensal microbiome may contribute to a number of acute, chronic, and post-infectious clinical manifestations of giardiasis and may account for variations in disease presentation within and between infected populations. This review discusses recent advances in characterizing Giardia-induced bacterial dysbiosis in the gut and the roles of dysbiosis in Giardia pathogenesis.
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Affiliation(s)
- Elena Fekete
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Inflammation Research Network, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB, Canada
| | - Thibault Allain
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Inflammation Research Network, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB, Canada
| | - Affan Siddiq
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Inflammation Research Network, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB, Canada
| | - Olivia Sosnowski
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Inflammation Research Network, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB, Canada
| | - Andre G. Buret
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
- Inflammation Research Network, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB, Canada
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ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol 2021; 116:17-44. [PMID: 33315591 DOI: 10.14309/ajg.0000000000001036] [Citation(s) in RCA: 338] [Impact Index Per Article: 112.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
Irritable bowel syndrome (IBS) is a highly prevalent, chronic disorder that significantly reduces patients' quality of life. Advances in diagnostic testing and in therapeutic options for patients with IBS led to the development of this first-ever American College of Gastroenterology clinical guideline for the management of IBS using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Twenty-five clinically important questions were assessed after a comprehensive literature search; 9 questions focused on diagnostic testing; 16 questions focused on therapeutic options. Consensus was obtained using a modified Delphi approach, and based on GRADE methodology, we endorse the following: We suggest that a positive diagnostic strategy as compared to a diagnostic strategy of exclusion be used to improve time to initiating appropriate therapy. We suggest that serologic testing be performed to rule out celiac disease in patients with IBS and diarrhea symptoms. We suggest that fecal calprotectin be checked in patients with suspected IBS and diarrhea symptoms to rule out inflammatory bowel disease. We recommend a limited trial of a low fermentable oligosaccharides, disacchardies, monosaccharides, polyols (FODMAP) diet in patients with IBS to improve global symptoms. We recommend the use of chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms. We recommend the use of rifaximin to treat global IBS with diarrhea symptoms. We suggest that gut-directed psychotherapy be used to treat global IBS symptoms. Additional statements and information regarding diagnostic strategies, specific drugs, doses, and duration of therapy can be found in the guideline.
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Martínez C, Lasitschka F, Thöni C, Wohlfarth C, Braun A, Granzow M, Röth R, Dizdar V, Rappold GA, Hausken T, Langeland N, Hanevik K, Niesler B. Comparative expression profiling in the intestine of patients with Giardia-induced postinfectious functional gastrointestinal disorders. Neurogastroenterol Motil 2020; 32:e13868. [PMID: 32391639 DOI: 10.1111/nmo.13868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/13/2020] [Accepted: 04/07/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND A Giardia outbreak in Bergen, Norway, caused postinfectious functional gastrointestinal disorders (PI-FGIDs). Despite the devastating effects of this outbreak, it presented a unique chance to investigate the implication on the dysregulation of genetic pathways in PI-FGID. METHODS We performed the first comparative expression profiling of miRNAs and their potential target genes in microdissected rectal biopsies from 20 Giardia-induced PI-FGID patients vs 18 healthy controls by nCounter analysis. Subsequently, candidates were validated on protein level by immunostaining. KEY RESULTS miRNA profiling on rectal biopsy samples from 5 diarrhea-predominant PI-IBS cases compared to 10 healthy controls revealed differential expression in the epithelial layer. The top five regulated miRNAs were implicated in GI disease, inflammatory response, and immunological disease. Subsequently, these miRNAs and 100 potential mRNA targets were examined in 20 PI-FGID cases and 18 healthy controls in both the mucosal epithelium and the lamina propria. Although deregulation of the selected miRNAs could not be verified in the larger sample set, mRNAs involved in barrier function were downregulated in the epithelium. Pro-inflammatory genes and genes implicated in epigenetic modifications were upregulated in the lamina propria. Immunostaining for selected candidates on 17 PI-FGID cases and 16 healthy controls revealed increased tryptase levels as well as a decreased and aberrant subcellular expression of occludin. CONCLUSIONS AND INFERENCES Genes relevant to immune and barrier function as well as stress response and epigenetic modulation are differentially expressed in PI-FGIDs and may contribute to disease manifestation.
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Affiliation(s)
- Cristina Martínez
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.,Lleida Institute for Biomedical Research Dr. Pifarré Foundation (IRBLleida), Lleida, Spain.,Genes in Irritable Bowel Syndrome (GENIEUR) Research Network Europe, Heidelberg, Germany
| | - Felix Lasitschka
- Institute of Pathology, Heidelberg University, Heidelberg, Germany
| | - Cornelia Thöni
- Institute of Pathology, Heidelberg University, Heidelberg, Germany
| | - Carolin Wohlfarth
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Alexander Braun
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Martin Granzow
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Ralph Röth
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.,nCounter Core Facility Heidelberg, Institute of Human Genetics, Heidelberg, Germany
| | - Vernesa Dizdar
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Gudrun A Rappold
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.,nCounter Core Facility Heidelberg, Institute of Human Genetics, Heidelberg, Germany
| | - Trygve Hausken
- Genes in Irritable Bowel Syndrome (GENIEUR) Research Network Europe, Heidelberg, Germany.,Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Nina Langeland
- Genes in Irritable Bowel Syndrome (GENIEUR) Research Network Europe, Heidelberg, Germany.,Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Kurt Hanevik
- Genes in Irritable Bowel Syndrome (GENIEUR) Research Network Europe, Heidelberg, Germany.,Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Medicine, National Advisory Center for Tropical Infectious Diseases, Haukeland University Hospital, Bergen, Norway
| | - Beate Niesler
- Department of Human Molecular Genetics, Institute of Human Genetics, Heidelberg University, Heidelberg, Germany.,Genes in Irritable Bowel Syndrome (GENIEUR) Research Network Europe, Heidelberg, Germany.,nCounter Core Facility Heidelberg, Institute of Human Genetics, Heidelberg, Germany
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25
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Buret AG, Cacciò SM, Favennec L, Svärd S. Update on Giardia: Highlights from the seventh International Giardia and Cryptosporidium Conference. ACTA ACUST UNITED AC 2020; 27:49. [PMID: 32788035 PMCID: PMC7425178 DOI: 10.1051/parasite/2020047] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/01/2020] [Indexed: 12/22/2022]
Abstract
Although Giardia duodenalis is recognized as one of the leading causes of parasitic human diarrhea in the world, knowledge of the mechanisms of infection is limited, as the pathophysiological consequences of infection remain incompletely elucidated. Similarly, the reason for and consequences of the very specific genome-organization in this parasite with 2 active nuclei is only partially known. Consistent with its tradition, the 7th International Giardia and Cryptosporidium Conference (IGCC 2019) was held from June 23 to 26, 2019, at the Faculty of Medicine and Pharmacy of the University of Rouen-Normandie, France, to discuss current research perspectives in the field. This renowned event brought together an international delegation of researchers to present and debate recent advances and identify the main research themes and knowledge gaps. The program for this interdisciplinary conference included all aspects of host-parasite relationships, from basic research to applications in human and veterinary medicine, as well as the environmental issues raised by water-borne parasites and their epidemiological consequences. With regard to Giardia and giardiasis, the main areas of research for which new findings and the most impressive communications were presented and discussed included: parasite ecology and epidemiology of giardiasis, Giardia-host interactions, and cell biology of Giardia, genomes and genomic evolution. The high-quality presentations discussed at the Conference noted breakthroughs and identified new opportunities that will inspire researchers and funding agencies to stimulate future research in a “one health” approach to improve basic knowledge and clinical and public health management of zoonotic giardiasis.
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Affiliation(s)
- André G Buret
- Biological Sciences, University of Calgary, TN4N1 Calgary (AB), Canada
| | - Simone M Cacciò
- Department of Infectious Diseases, Istituto Superiore di Sanita, 00161 Rome, Italy
| | - Loïc Favennec
- French National Cryptosporidiosis Reference Center, Rouen University Hospital, 1 rue de Germont, 76031 Rouen cedex, France - EA 7510, UFR Santé, University of Rouen Normandy, Normandy University, 22 bd Gambetta, 76183 Rouen cedex, France
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, SE 75124 Uppsala, Sweden
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26
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Ashour DS, Othman AA. Parasite-bacteria interrelationship. Parasitol Res 2020; 119:3145-3164. [PMID: 32748037 DOI: 10.1007/s00436-020-06804-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/06/2020] [Indexed: 12/18/2022]
Abstract
Parasites and bacteria have co-evolved with humankind, and they interact all the time in a myriad of ways. For example, some bacterial infections result from parasite-dwelling bacteria as in the case of Salmonella infection during schistosomiasis. Other bacteria synergize with parasites in the evolution of human disease as in the case of the interplay between Wolbachia endosymbiont bacteria and filarial nematodes as well as the interaction between Gram-negative bacteria and Schistosoma haematobium in the pathogenesis of urinary bladder cancer. Moreover, secondary bacterial infections may complicate several parasitic diseases such as visceral leishmaniasis and malaria, due to immunosuppression of the host during parasitic infections. Also, bacteria may colonize the parasitic lesions; for example, hydatid cysts and skin lesions of ectoparasites. Remarkably, some parasitic helminths and arthropods exhibit antibacterial activity usually by the release of specific antimicrobial products. Lastly, some parasite-bacteria interactions are induced as when using probiotic bacteria to modulate the outcome of a variety of parasitic infections. In sum, parasite-bacteria interactions involve intricate processes that never cease to intrigue the researchers. However, understanding and exploiting these interactions could have prophylactic and curative potential for infections by both types of pathogens.
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Affiliation(s)
- Dalia S Ashour
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, 31527, Egypt.
| | - Ahmad A Othman
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, 31527, Egypt
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27
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Giardia spp. promote the production of antimicrobial peptides and attenuate disease severity induced by attaching and effacing enteropathogens via the induction of the NLRP3 inflammasome. Int J Parasitol 2020; 50:263-275. [PMID: 32184085 DOI: 10.1016/j.ijpara.2019.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/12/2019] [Accepted: 12/28/2019] [Indexed: 12/14/2022]
Abstract
Polymicrobial infections of the gastro-intestinal tract are common in areas with poor sanitation. Disease outcome is the result of complex interactions between the host and pathogens. Such interactions lie at the core of future management strategies of enteric diseases. In developed countries of the world, Giardia duodenalis is a common cause of diarrheal disease. In contrast, giardiasis appears to protect children against diarrhea in countries with poor sanitation, via obscure mechanisms. We hypothesized that Giardia may protect its host from disease induced by a co-infecting pathogen such as attaching and effacing Escherichia coli. This enteropathogen is commonly implicated in pediatric diarrhea in developing countries. The findings indicate that co-infection with Giardia attenuates the severity of disease induced by Citrobacter rodentium, an equivalent of A/E E. coli in mice. Co-infection with Giardia reduced colitis, blood in stools, fecal softening, bacterial invasion, and weight loss; the protective effects were lost when co-infection occurred in Nod-like receptor pyrin-containing 3 knockout mice. In co-infected mice, elevated levels of antimicrobial peptides Murine β defensin 3 and Trefoil Factor 3, and enhanced bacterial killing, were NLRP3-dependent. Inhibition of the NLRP3 inflammasome in human enterocytes blocked the activation of AMPs and bacterial killing. The findings uncover novel NLRP3-dependent modulatory mechanisms during co-infections with Giardia spp. and A/E enteropathogens, and demonstrate how these interactions may regulate the severity of enteric disease.
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28
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Buret AG. Acceptance of the 2019 Stoll-Stunkard Memorial Lectureship Award: The Study of Host-Parasite Interactions to Better Understand Fundamental Host Physiology: The Model of Giardiasis. J Parasitol 2020. [DOI: 10.1645/19-134] [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] Open
Affiliation(s)
- André G. Buret
- Department of Biological Sciences, Host-Parasite Interactions Program, Inflammation Research Network, University of Calgary, 2500 University Drive N.W., Calgary (Alberta), T2N 1N4, Canada
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Allain T, Buret AG. Pathogenesis and post-infectious complications in giardiasis. ADVANCES IN PARASITOLOGY 2019; 107:173-199. [PMID: 32122529 DOI: 10.1016/bs.apar.2019.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Giardia is an important cause of diarrhoea, and results in post-infectious and extra-intestinal complications. This chapter presents a state-of-the art of our understanding of how this parasite may cause such abnormalities, which appear to develop at least in part in Assemblage-dependent manner. Findings from prospective longitudinal cohort studies indicate that Giardia is one of the four most prevalent enteropathogens in early life, and represents a risk factor for stunting at 2 years of age. This may occur independently of diarrheal disease, in strong support of the pathophysiological significance of the intestinal abnormalities induced by this parasite. These include epithelial malabsorption and maldigestion, increased transit, mucus depletion, and disruptions of the commensal microbiota. Giardia increases epithelial permeability and facilitates the invasion of gut bacteria. Loss of intestinal barrier function is at the core of the acute and post-infectious complications associated with this infection. Recent findings demonstrate that the majority of the pathophysiological responses triggered by this parasite can be recapitulated by the effects of its membrane-bound and secreted cysteine proteases.
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Affiliation(s)
- Thibault Allain
- University of Calgary, Host-Parasite Interactions Program, Inflammation Research Network, Department of Biological Sciences, Calgary, Canada
| | - André G Buret
- University of Calgary, Host-Parasite Interactions Program, Inflammation Research Network, Department of Biological Sciences, Calgary, Canada.
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30
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van Thiel IAM, Botschuijver S, de Jonge WJ, Seppen J. Painful interactions: Microbial compounds and visceral pain. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165534. [PMID: 31634534 DOI: 10.1016/j.bbadis.2019.165534] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 12/18/2022]
Abstract
Visceral pain, characterized by abdominal discomfort, originates from organs in the abdominal cavity and is a characteristic symptom in patients suffering from irritable bowel syndrome, vulvodynia or interstitial cystitis. Most organs in which visceral pain originates are in contact with the external milieu and continuously exposed to microbes. In order to maintain homeostasis and prevent infections, the immune- and nervous system in these organs cooperate to sense and eliminate (harmful) microbes. Recognition of microbial components or products by receptors expressed on cells from the immune and nervous system can activate immune responses but may also cause pain. We review the microbial compounds and their receptors that could be involved in visceral pain development.
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Affiliation(s)
- I A M van Thiel
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, location AMC, Meibergdreef 69, 1105 BK Amsterdam, the Netherlands
| | - S Botschuijver
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, location AMC, Meibergdreef 69, 1105 BK Amsterdam, the Netherlands
| | - W J de Jonge
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, location AMC, Meibergdreef 69, 1105 BK Amsterdam, the Netherlands
| | - J Seppen
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, location AMC, Meibergdreef 69, 1105 BK Amsterdam, the Netherlands.
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Li Z, Peirasmaki D, Svärd S, Åbrink M. Giardia excretory-secretory proteins modulate the enzymatic activities of mast cell chymase and tryptase. Mol Immunol 2019; 114:535-544. [PMID: 31518857 DOI: 10.1016/j.molimm.2019.07.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/22/2019] [Accepted: 07/25/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Mast cells are involved in the host immune response controlling infection with the non-invasive intestinal protozoan parasite Giardia intestinalis. Experimental infections in rodents with G. intestinalis showed increased intestinal expression of mucosal and connective mast cell specific proteases suggesting that both mucosal and connective tissue mast cells are recruited and activated during infection. During infection Giardia excretory-secretory proteins (ESPs) with immunomodulatory capacity are released. However, studies investigating potential interactions between Giardia ESPs and the connective tissue mast cell specific serine proteases, i.e. human chymase and mouse mast cell protease (mMCP)-4 and, human and mouse tryptase (mMCP-6) remain scarce. RESULTS We first investigated if soluble Giardia proteins (sGPs), which over-lap extensively in protein content with ESP fractions, from the isolates GS, WB and H3, could induce mast cell activation. sGPs induced a minor activation of bone marrow derived mucosal-like mast cells, as indicated by increased IL-6 secretion and no degranulation. Furthermore, sGPs were highly resistant to degradation by human tryptase while human chymase degraded a 65 kDa sGP and, wild-type mouse ear tissue extracts degraded several protein bands in the 10 to 75 kDa range. In striking contrast, sGPs and ESPs were found to increase the enzymatic activity of human and mouse tryptase and to reduce the activity of human and mouse chymase. CONCLUSION Our finding suggests that Giardia ssp. via enhancement or reduction of mast cell protease activity may modulate mast cell-driven intestinal immune responses. ESP-mediated modulation of the mast cell specific proteases may also increase degradation of tight junctions, which may be beneficial for Giardia ssp. during infection.
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Affiliation(s)
- Zhiqiang Li
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular Biology, Uppsala University, SE-75124 Uppsala, Sweden
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, SE-75124 Uppsala, Sweden
| | - Magnus Åbrink
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden.
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32
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Liu J, Fu Z, Hellman L, Svärd SG. Cleavage specificity of recombinant Giardia intestinalis cysteine proteases: Degradation of immunoglobulins and defensins. Mol Biochem Parasitol 2019; 227:29-38. [DOI: 10.1016/j.molbiopara.2018.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 10/17/2018] [Accepted: 10/26/2018] [Indexed: 12/11/2022]
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Barbara G, Grover M, Bercik P, Corsetti M, Ghoshal UC, Ohman L, Rajilić-Stojanović M. Rome Foundation Working Team Report on Post-Infection Irritable Bowel Syndrome. Gastroenterology 2019; 156:46-58.e7. [PMID: 30009817 PMCID: PMC6309514 DOI: 10.1053/j.gastro.2018.07.011] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS The existence of postinfection irritable bowel syndrome (PI-IBS) has been substantiated by epidemiology studies conducted in diverse geographic and clinical settings. However, the available evidence has not been well summarized, and there is little guidance for diagnosis and treatment of PI-IBS. The ROME Foundation has produced a working team report to summarize the available evidence on the pathophysiology of PI-IBS and provide guidance for diagnosis and treatment, based on findings reported in the literature and clinical experience. METHODS The working team conducted an evidence-based review of publication databases for articles describing the clinical features (diagnosis), pathophysiology (intestinal sensorimotor function, microbiota, immune dysregulation, barrier dysfunction, enteroendocrine pathways, and genetics), and animal models of PI-IBS. We used a Delphi-based consensus system to create guidelines for management of PI-IBS and a developed treatment algorithm based on published findings and experiences of team members. RESULTS PI-IBS develops in about 10% of patients with infectious enteritis. Risk factors include female sex, younger age, psychological distress during or before acute gastroenteritis, and severity of the acute episode. The pathogenesis of PI-PBS appears to involve changes in the intestinal microbiome as well as epithelial, serotonergic, and immune system factors. However, these mechanisms are incompletely understood. There are no evidence-based, effective pharmacologic strategies for treatment of PI-IBS. We provide a consensus-based treatment algorithm, based on clinical presentation and potential disease mechanisms. CONCLUSIONS Based on a systematic review of the literature and team experience, we summarize the clinical features, pathophysiology (from animal models and human studies), and progression of PI-IBS. Based on these findings, we present an algorithm for diagnosis and treatment of PI-IBS based on team consensus. We also propose areas for future investigation.
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Affiliation(s)
- Giovanni Barbara
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy.
| | - Madhusudan Grover
- Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Premysl Bercik
- Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Maura Corsetti
- Nottingham Digestive Diseases Biomedical Research Centre, National Institute for Health Research, Nottingham University Hospitals NHS Trust, University of Nottingham, UK
| | - Uday C Ghoshal
- Department of Gastroenterology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India
| | - Lena Ohman
- Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mirjana Rajilić-Stojanović
- Department of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
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Leon-Coria A, Kumar M, Moreau F, Chadee K. Defining cooperative roles for colonic microbiota and Muc2 mucin in mediating innate host defense against Entamoeba histolytica. PLoS Pathog 2018; 14:e1007466. [PMID: 30500860 PMCID: PMC6268003 DOI: 10.1371/journal.ppat.1007466] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/11/2018] [Indexed: 12/19/2022] Open
Abstract
Amebiasis is caused by the protozoan parasite Entamoeba histolytica (Eh), a potentially fatal disease occurring mainly in developing countries. How Eh interacts with innate host factors in the gut is poorly understood. Eh resides and feed in/on the outer colonic mucus layer and thus share an ecological niche with indigenous microbiota. As gut microbiota regulates innate immune responses, in this study we characterized the cooperative roles that microbiota and the mucus layer play in Eh-induced pro-inflammatory responses in the colon. To study this, we used antibiotics treated and non-treated specific pathogen free Muc2-/- and Muc2+/+ littermates and germ-free mice inoculated with Eh in colonic loops as a short infection model. In antibiotic treated Muc2-/- and Muc2+/+ littermates, Eh elicited robust mucus and water secretions, enhanced pro-inflammatory cytokines and chemokine expression with elevated MPO activity and higher pathology scores as compared to the modest response observed in non-antibiotic treated littermates. Host responses were microbiota specific as mucus secretion and pro-inflammatory responses were attenuated following homologous fecal microbial transplants in antibiotic-treated Muc2+/+ quantified by secretion of 3H-glucosamine newly synthesized mucin, Muc2 mucin immunostaining and immunohistochemistry. Eh-elicited pro-inflammatory responses and suppressed goblet cell transcription factor Math1 as revealed by in vivo imaging of Eh-colonic loops in Math1GFP mice, and in vitro using Eh-stimulated LS174T human colonic goblet cells. Eh in colonic loops increased bacterial translocation of bioluminescent E. coli and indigenous bacteria quantified by FISH and quantitative PCR. In germ-free animals, Eh-induced mucus/water secretory responses, but acute pro-inflammatory responses and MPO activity were severely impaired, allowing the parasite to bind to and disrupt mucosal epithelial cells. These findings have identified key roles for intestinal microbiota and mucus in regulating innate host defenses against Eh, and implicate dysbiosis as a risk factor for amebiasis that leads to exacerbated immune responses to cause life-threatening disease.
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Affiliation(s)
- Aralia Leon-Coria
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Manish Kumar
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, Canada
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Liu J, Ma'ayeh S, Peirasmaki D, Lundström-Stadelmann B, Hellman L, Svärd SG. Secreted Giardia intestinalis cysteine proteases disrupt intestinal epithelial cell junctional complexes and degrade chemokines. Virulence 2018; 9:879-894. [PMID: 29726306 PMCID: PMC5955458 DOI: 10.1080/21505594.2018.1451284] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Giardiasis is a common diarrheal disease caused by the protozoan parasite Giardia intestinalis. Cysteine proteases (CPs) are acknowledged as virulence factors in Giardia but their specific role in the molecular pathogenesis of disease is not known. Herein, we aimed to characterize the three main secreted CPs (CP14019, CP16160 and CP16779), which were identified by mass spectrometry in the medium during interaction with intestinal epithelial cells (IECs) in vitro. First, the CPs were epitope-tagged and localized to the endoplasmic reticulum and cytoplasmic vesicle-like structures. Second, we showed that recombinant CPs, expressed in Pichia pastoris, are more active in acidic environment (pH 5.5-6) and we determined the kinetic parameters using fluorogenic substrates. Third, excretory-secretory proteins (ESPs) from Giardia trophozoites affect the localization of apical junctional complex (AJC) proteins and recombinant CPs cleave or re-localize the AJC proteins (claudin-1 and -4, occludin, JAM-1, β-catenin and E-cadherin) of IECs. Finally, we showed that the ESPs and recombinant CPs can degrade several chemokines, including CXCL1, CXCL2, CXCL3, IL-8, CCL2, and CCL20, which are up-regulated in IECs during Giardia-host cell interactions. This is the first study that characterizes the role of specific CPs secreted from Giardia and our results collectively indicate their roles in the disruption of the intestinal epithelial barrier and modulating immune responses during Giardia infections.
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Affiliation(s)
- Jingyi Liu
- a Department of Cell and Molecular Biology , Uppsala University , Uppsala , Sweden
| | - Showgy Ma'ayeh
- a Department of Cell and Molecular Biology , Uppsala University , Uppsala , Sweden
| | - Dimitra Peirasmaki
- a Department of Cell and Molecular Biology , Uppsala University , Uppsala , Sweden
| | | | - Lars Hellman
- a Department of Cell and Molecular Biology , Uppsala University , Uppsala , Sweden
| | - Staffan G Svärd
- a Department of Cell and Molecular Biology , Uppsala University , Uppsala , Sweden
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Yordanova IA, Zakovic S, Rausch S, Costa G, Levashina E, Hartmann S. Micromanaging Immunity in the Murine Host vs. the Mosquito Vector: Microbiota-Dependent Immune Responses to Intestinal Parasites. Front Cell Infect Microbiol 2018; 8:308. [PMID: 30234029 PMCID: PMC6129580 DOI: 10.3389/fcimb.2018.00308] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022] Open
Abstract
The digestive tract plays a central role in nutrient acquisition and harbors a vast and intricate community of bacteria, fungi, viruses and parasites, collectively known as the microbiota. In recent years, there has been increasing recognition of the complex and highly contextual involvement of this microbiota in the induction and education of host innate and adaptive immune responses under homeostasis, during infection and inflammation. The gut passage and colonization by unicellular and multicellular parasite species present an immense challenge to the host immune system and to the microbial communities that provide vital support for its proper functioning. In mammals, parasitic nematodes induce distinct shifts in the intestinal microbial composition. Vice versa, the commensal microbiota has been shown to serve as a molecular adjuvant and immunomodulator during intestinal parasite infections. Moreover, similar interactions occur within insect vectors of deadly human pathogens. The gut microbiota has emerged as a crucial factor affecting vector competence in Anopheles mosquitoes, where it modulates outcomes of infections with malaria parasites. In this review, we discuss currently known involvements of the host microbiota in the instruction, support or suppression of host immune responses to gastrointestinal nematodes and protozoan parasites in mice, as well as in the malaria mosquito vector. A deeper understanding of the mechanisms underlying microbiota-dependent modulation of host and vector immunity against parasites in mammals and mosquitoes is key to a better understanding of the host-parasite relationships and the identification of more efficient approaches for intervention and treatment of parasite infections of both clinical and veterinary importance.
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Affiliation(s)
- Ivet A. Yordanova
- Center for Infection Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Suzana Zakovic
- Vector Biology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Sebastian Rausch
- Center for Infection Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
| | - Giulia Costa
- Vector Biology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Elena Levashina
- Vector Biology Unit, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Susanne Hartmann
- Center for Infection Medicine, Institute of Immunology, Freie Universität Berlin, Berlin, Germany
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Ma'ayeh SY, Knörr L, Sköld K, Garnham A, Ansell BRE, Jex AR, Svärd SG. Responses of the Differentiated Intestinal Epithelial Cell Line Caco-2 to Infection With the Giardia intestinalis GS Isolate. Front Cell Infect Microbiol 2018; 8:244. [PMID: 30062089 PMCID: PMC6055019 DOI: 10.3389/fcimb.2018.00244] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/25/2018] [Indexed: 12/11/2022] Open
Abstract
Giardia intestinalis is a parasitic protist that causes diarrhea in humans, affecting mainly children of the developing world, elderly and immunocompromised individuals. Humans are infected by two major Giardia assemblages (i.e. genetic subtypes), A and B, with the latter being the most common. So far, there is little information on molecular or cellular changes during infections with assemblage B. Here, we used RNA sequencing to study transcriptional changes in Caco-2 intestinal epithelial cells (IECs) co-incubated with assemblage B (GS isolate) trophozoites for 1.5, 3, and 4.5 h. We aimed to identify early molecular events associated with the establishment of infection and followed cellular protein changes up to 10 h. IEC transcriptomes showed a dominance of immediate early response genes which was sustained across all time points. Transcription of inflammatory cytokines (e.g., cxcl1-3, ccl2, 1l1a, and il1b) peaked at 1.5 and 3 h of infection. Compared to co-incubation with assemblage A Giardia, we identified the induction of novel cytokines (cxcl8, cxcl10, csf1, cx3cl1, il12a, il11) and showed that inflammatory signaling is mediated by Erk1/2 phosphorylation (mitogen activated protein kinase, MAPK), nuclear factor kappa B (NFκB) and adaptor protein-1 (AP-1). We also showed that GS trophozoites attenuate P38 (MAPK) phosphorylation in IECs. Low amounts of IL-8, CXCL1 and CCL20 proteins were measured in the interaction medium, which was attributed to cytokine degradation by trophozoite secreted proteases. Based on the transcriptome, the decay of cytokines mRNA mediated by zinc finger protein 36 might be another mechanism controlling cytokine levels at later time points. IEC transcriptomes suggested homeostatic responses to counter oxidative stress, glucose starvation, and disturbances in amino acid and lipid metabolism. A large group of differentially transcribed genes were associated with cell cycle arrest and induction of apoptosis, which was validated at protein level. IEC transcriptomes also suggested changes in tight junction's integrity, microvilli structure and the extracellular mucin layer. This is the first study to illuminate transcriptional and protein regulatory events underlying IECs responses and pathogenesis during Giardia assemblage B infection. It highlights differences compared to assemblage A infections which might account for the differences observed in human infections with the two assemblages.
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Affiliation(s)
- Showgy Y Ma'ayeh
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Livia Knörr
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Karin Sköld
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Alexandra Garnham
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Brendan R E Ansell
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC, Australia
| | - Aaron R Jex
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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Coronado-Velázquez D, Betanzos A, Serrano-Luna J, Shibayama M. An In Vitro Model of the Blood-Brain Barrier: Naegleria fowleri Affects the Tight Junction Proteins and Activates the Microvascular Endothelial Cells. J Eukaryot Microbiol 2018; 65:804-819. [PMID: 29655298 DOI: 10.1111/jeu.12522] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/05/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Abstract
Naegleria fowleri causes a fatal disease known as primary amoebic meningoencephalitis. This condition is characterized by an acute inflammation that originates from the free passage of peripheral blood cells to the central nervous system through the alteration of the blood-brain barrier. In this work, we established models of the infection in rats and in a primary culture of endothelial cells from rat brains with the aim of evaluating the activation and the alterations of these cells by N. fowleri. We proved that the rat develops the infection similar to the mouse model. We also found that amoebic cysteine proteases produced by the trophozoites and the conditioned medium induced cytopathic effect in the endothelial cells. In addition, N. fowleri can decrease the transendothelial electrical resistance by triggering the destabilization of the tight junction proteins claudin-5, occludin, and ZO-1 in a time-dependent manner. Furthermore, N. fowleri induced the expression of VCAM-1 and ICAM-1 and the production of IL-8, IL-1β, TNF-α, and IL-6 as well as nitric oxide. We conclude that N. fowleri damaged the blood-brain barrier model by disrupting the intercellular junctions and induced the presence of inflammatory mediators by allowing the access of inflammatory cells to the olfactory bulbs.
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Affiliation(s)
- Daniel Coronado-Velázquez
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Av. IPN 2508, Mexico City, 07360, Mexico
| | - Abigail Betanzos
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Av. IPN 2508, Mexico City, 07360, Mexico
| | - Jesús Serrano-Luna
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute, Av. IPN 2508, Mexico City, 07360, Mexico
| | - Mineko Shibayama
- Department of Infectomics and Molecular Pathogenesis, Center for Research and Advanced Studies of the National Polytechnic Institute, Av. IPN 2508, Mexico City, 07360, Mexico
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Abstract
PURPOSE OF REVIEW Giardia is a common intestinal parasite worldwide, and infection can be associated with clear and sometimes persistent symptomatology. However, in children in high-prevalence settings, it is not associated with or is perhaps even protective against acute diarrhea, and the association with long-term outcomes has been difficult to discern. RECENT FINDINGS Recent studies have made progress in helping us disentangle this apparent paradox. First, prospective, well-characterized cohort studies have added to the data on the association between Giardia and diarrhea in these settings and have further characterized associations between Giardia infection and nutrition, gut function, and growth. Second, animal models have further characterized the host response to Giardia and helped elucidate mechanisms by which Giardia could impair child development. Finally, new work has shed light on the heterogeneity of human Giardia strains, which may both explain discrepant findings in the literature and help guide higher-resolution analyses of this pathogen in the future. SUMMARY The true clinical impact of endemic pediatric giardiasis remains unclear, but recent prospective studies have confirmed a high prevalence of persistent, subclinical Giardia infections and associated growth shortfalls. Integrating how nutritional, microbial, metabolic, and pathogen-strain variables influence these outcomes could sharpen delineations between pathogenic and potentially beneficial attributes of this enigmatic parasite.
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40
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Bednarska O, Walter SA, Casado-Bedmar M, Ström M, Salvo-Romero E, Vicario M, Mayer EA, Keita ÅV. Vasoactive Intestinal Polypeptide and Mast Cells Regulate Increased Passage of Colonic Bacteria in Patients With Irritable Bowel Syndrome. Gastroenterology 2017; 153:948-960.e3. [PMID: 28711627 PMCID: PMC5623149 DOI: 10.1053/j.gastro.2017.06.051] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 06/13/2017] [Accepted: 06/30/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Irritable bowel syndrome (IBS) is associated with intestinal dysbiosis and symptoms of IBS develop following gastroenteritis. We aimed to study the passage of live bacteria through the colonic epithelium, and determine the role of mast cells (MCs) and vasoactive intestinal polypeptide (VIP) in barrier regulation in IBS and healthy individuals. METHODS Colon biopsies from 32 women with IBS and 15 age-matched healthy women (controls) were mounted in Ussing chambers; we measured numbers of fluorescently labeled Escherichia coli HS and Salmonella typhimurium that passed through from the mucosal side to the serosal side of the tissue. Some biopsies were exposed to agents that block the VIP receptors (VPAC1 and VPAC2) or MCs. Levels of VIP and tryptase were measured in plasma and biopsy lysates. Number of MCs and MCs that express VIP or VIP receptors were quantified by immunofluorescence. Biopsies from an additional 5 patients with IBS and 4 controls were mounted in chambers and Salmonella were added; we studied passage routes through the epithelium by transmission electron microscopy and expression of tight junctions by confocal microscopy. RESULTS In colon biopsies from patients with IBS, larger numbers of E coli HS and S typhimurium passed through the epithelium than in biopsies from controls (P < .0005). In transmission electron microscopy analyses, bacteria were found to cross the epithelium via only the transcellular route. Bacterial passage was reduced in biopsies from patients with IBS and controls after addition of antibodies against VPACs or ketotifen, which inhibits MCs. Plasma samples from patients with IBS had higher levels of VIP than plasma samples from controls. Biopsies from patients with IBS had higher levels of tryptase, larger numbers of MCs, and a higher percentage of MCs that express VPAC1 than biopsies from controls. In biopsies from patients with IBS, addition of Salmonella significantly reduced levels of occludin; subsequent addition of ketotifen significantly reversed this effect. CONCLUSIONS We found that colonic epithelium tissues from patients with IBS have increased translocation of commensal and pathogenic live bacteria compared with controls. The mechanisms of increased translocation include MCs and VIP.
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Affiliation(s)
- Olga Bednarska
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden; Department of Gastroenterology, Linköping University, Linköping, Sweden
| | - Susanna A Walter
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden; Department of Gastroenterology, Linköping University, Linköping, Sweden
| | - Maite Casado-Bedmar
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Magnus Ström
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden; Department of Gastroenterology, Linköping University, Linköping, Sweden
| | - Eloísa Salvo-Romero
- Laboratory of Translational Mucosal Immunology, Digestive Diseases Research Unit, Vall d'Hebron Institut de Recerca, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Spain
| | - Maria Vicario
- Laboratory of Translational Mucosal Immunology, Digestive Diseases Research Unit, Vall d'Hebron Institut de Recerca, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Spain
| | - Emeran A Mayer
- G Oppenheimer Center for Neurobiology of Stress & Resilience, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Åsa V Keita
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
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Kraft MR, Klotz C, Bücker R, Schulzke JD, Aebischer T. Giardia's Epithelial Cell Interaction In Vitro: Mimicking Asymptomatic Infection? Front Cell Infect Microbiol 2017; 7:421. [PMID: 29018775 PMCID: PMC5622925 DOI: 10.3389/fcimb.2017.00421] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/12/2017] [Indexed: 12/13/2022] Open
Abstract
The protozoan parasite Giardia duodenalis is responsible for more than 280 million cases of gastrointestinal complaints ("giardiasis") every year, worldwide. Infections are acquired orally, mostly via uptake of cysts in contaminated drinking water. After transformation into the trophozoite stage, parasites start to colonize the duodenum and upper jejunum where they attach to the intestinal epithelium and replicate vegetatively. Outcome of Giardia infections vary between individuals, from self-limiting to chronic, and asymptomatic to severely symptomatic infection, with unspecific gastrointestinal complaints. One proposed mechanism for pathogenesis is the breakdown of intestinal barrier function. This has been studied by analyzing trans-epithelial electric resistances (TEER) or by indicators of epithelial permeability using labeled sugar compounds in in vitro cell culture systems, mouse models or human biopsies and epidemiological studies. Here, we discuss the results obtained mainly with epithelial cell models to highlight contradictory findings. We relate published studies to our own findings that suggest a lack of barrier compromising activities of recent G. duodenalis isolates of assemblage A, B, and E in a Caco-2 model system. We propose that this epithelial cell model be viewed as mimicking asymptomatic infection. This view will likely lead to a more informative use of the model if emphasis is shifted from aiming to identify Giardia virulence factors to defining non-parasite factors that arguably appear to be more decisive for disease.
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Affiliation(s)
- Martin R Kraft
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany.,Institute of Clinical Physiology, Charité Campus Benjamin Franklin, Berlin, Germany
| | - Christian Klotz
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Roland Bücker
- Institute of Clinical Physiology, Charité Campus Benjamin Franklin, Berlin, Germany
| | - Jörg-Dieter Schulzke
- Institute of Clinical Physiology, Charité Campus Benjamin Franklin, Berlin, Germany
| | - Toni Aebischer
- Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
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42
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Fink MY, Singer SM. The Intersection of Immune Responses, Microbiota, and Pathogenesis in Giardiasis. Trends Parasitol 2017; 33:901-913. [PMID: 28830665 DOI: 10.1016/j.pt.2017.08.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/18/2017] [Accepted: 08/01/2017] [Indexed: 02/07/2023]
Abstract
Giardia lamblia is one of the most common infectious protozoans in the world. Giardia rarely causes severe life-threatening diarrhea, and may even have a slight protective effect in this regard, but it is a major contributor to malnutrition and growth faltering in children in the developing world. Giardia infection also appears to be a significant risk factor for postinfectious irritable bowel and chronic fatigue syndromes. In this review we highlight recent work focused on the impact of giardiasis and the mechanisms that contribute to the various outcomes of this infection, including changes in the composition of the microbiota, activation of immune responses, and immunopathology.
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Affiliation(s)
- Marc Y Fink
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Steven M Singer
- Department of Biology, Georgetown University, Washington, DC, USA.
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43
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Amat CB, Motta JP, Fekete E, Moreau F, Chadee K, Buret AG. Cysteine Protease-Dependent Mucous Disruptions and Differential Mucin Gene Expression in Giardia duodenalis Infection. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2486-2498. [PMID: 28823873 DOI: 10.1016/j.ajpath.2017.07.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/04/2017] [Accepted: 07/06/2017] [Indexed: 02/08/2023]
Abstract
The intestinal mucous layer provides a critical host defense against pathogen exposure and epithelial injury, yet little is known about how enteropathogens may circumvent this physiologic barrier. Giardia duodenalis is a small intestinal parasite responsible for diarrheal disease and chronic postinfectious illness. This study reveals a complex interaction at the surface of epithelial cells, between G. duodenalis and the intestinal mucous layer. Here, we reveal mechanisms whereby G. duodenalis evades and disrupts the first line of host defense by degrading human mucin-2 (MUC2), depleting mucin stores and inducing differential gene expression in the mouse small and large intestines. Human colonic biopsy specimens exposed to G. duodenalis were depleted of mucus, and in vivo mice infected with G. duodenalis had a thinner mucous layer and demonstrated differential Muc2 and Muc5ac mucin gene expression. Infection in Muc2-/- mice elevated trophozoite colonization in the small intestine and impaired weight gain. In vitro, human LS174T goblet-like cells were depleted of mucus and had elevated levels of MUC2 mRNA expression after G. duodenalis exposure. Importantly, the cysteine protease inhibitor E64 prevented mucous degradation, mucin depletion, and the increase in MUC2 expression. This article describes a novel role for Giardia's cysteine proteases in pathogenesis and how Giardia's disruptions of the mucous barrier facilitate bacterial translocation that may contribute to the onset and propagation of disease.
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Affiliation(s)
- Christina B Amat
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Jean-Paul Motta
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Elena Fekete
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, Calgary, Alberta, Canada.
| | - Andre G Buret
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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44
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Bartelt LA, Bolick DT, Mayneris-Perxachs J, Kolling GL, Medlock GL, Zaenker EI, Donowitz J, Thomas-Beckett RV, Rogala A, Carroll IM, Singer SM, Papin J, Swann JR, Guerrant RL. Cross-modulation of pathogen-specific pathways enhances malnutrition during enteric co-infection with Giardia lamblia and enteroaggregative Escherichia coli. PLoS Pathog 2017; 13:e1006471. [PMID: 28750066 PMCID: PMC5549954 DOI: 10.1371/journal.ppat.1006471] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/14/2017] [Indexed: 12/17/2022] Open
Abstract
Diverse enteropathogen exposures associate with childhood malnutrition. To
elucidate mechanistic pathways whereby enteric microbes interact during
malnutrition, we used protein deficiency in mice to develop a new model of
co-enteropathogen enteropathy. Focusing on common enteropathogens in
malnourished children, Giardia lamblia and enteroaggregative
Escherichia coli (EAEC), we provide new insights into
intersecting pathogen-specific mechanisms that enhance malnutrition. We show for
the first time that during protein malnutrition, the intestinal microbiota
permits persistent Giardia colonization and simultaneously
contributes to growth impairment. Despite signals of intestinal injury, such as
IL1α, Giardia-infected mice lack pro-inflammatory intestinal
responses, similar to endemic pediatric Giardia infections.
Rather, Giardia perturbs microbial host co-metabolites of
proteolysis during growth impairment, whereas host nicotinamide utilization
adaptations that correspond with growth recovery increase. EAEC promotes
intestinal inflammation and markers of myeloid cell activation. During
co-infection, intestinal inflammatory signaling and cellular recruitment
responses to EAEC are preserved together with a
Giardia-mediated diminishment in myeloid cell activation.
Conversely, EAEC extinguishes markers of host energy expenditure regulatory
responses to Giardia, as host metabolic adaptations appear
exhausted. Integrating immunologic and metabolic profiles during co-pathogen
infection and malnutrition, we develop a working mechanistic model of how
cumulative diet-induced and pathogen-triggered microbial perturbations result in
an increasingly wasted host. Malnourished children are exposed to multiple sequential, and oftentimes,
persistent enteropathogens. Intestinal microbial disruption and inflammation are
known to contribute to the pathogenesis of malnutrition, but how co-pathogens
interact with each other, with the resident microbiota, or with the host to
alter these pathways is unknown. Using a new model of enteric co-infection with
Giardia lamblia and enteroaggregative Escherichia
coli in mice fed a protein deficient diet, we identify host growth
and intestinal immune responses that are differentially mediated by
pathogen-microbe interactions, including parasite-mediated changes in intestinal
microbial host co-metabolism, and altered immune responses during co-infection.
Our data model how early life cumulative enteropathogen exposures progressively
disrupt intestinal immunity and host metabolism during crucial developmental
periods. Furthermore, studies in this co-infection model reveal new insights
into environmental and microbial determinants of pathogenicity for presently
common, but poorly understood enteropathogens like Giardia
lamblia, that may not conform to existing paradigms of microbial
pathogenesis based on single pathogen-designed models.
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Affiliation(s)
- Luther A. Bartelt
- Division of Infectious Diseases, Department of Medicine, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of
America
- Center for Gastrointestinal Biology and Disease, Department of Medicine,
University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United
States of America
- * E-mail:
| | - David T. Bolick
- Division of Infectious Diseases and International Health, Department of
Medicine, University of Virginia, Charlottesville, Virginia, United States of
America
| | - Jordi Mayneris-Perxachs
- Division of Computational and Systems Medicine, Department of Surgery and
Cancer, Imperial College London, United Kingdom
| | - Glynis L. Kolling
- Division of Infectious Diseases and International Health, Department of
Medicine, University of Virginia, Charlottesville, Virginia, United States of
America
| | - Gregory L. Medlock
- Department of Biomedical Engineering, University of Virginia,
Charlottesville, Virginia, United States of America
| | - Edna I. Zaenker
- Division of Infectious Diseases and International Health, Department of
Medicine, University of Virginia, Charlottesville, Virginia, United States of
America
| | - Jeffery Donowitz
- Division of Pediatric Infectious Diseases, Children’s Hospital of
Richmond at Virginia Commonwealth University, Richmond, Virginia, United States
of America
| | - Rose Viguna Thomas-Beckett
- Division of Infectious Diseases, Department of Medicine, University of
North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of
America
| | - Allison Rogala
- Center for Gastrointestinal Biology and Disease, Department of Medicine,
University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United
States of America
| | - Ian M. Carroll
- Center for Gastrointestinal Biology and Disease, Department of Medicine,
University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United
States of America
| | - Steven M. Singer
- Department of Biology, Georgetown University, Washington, DC, United
States of America
| | - Jason Papin
- Department of Biomedical Engineering, University of Virginia,
Charlottesville, Virginia, United States of America
| | - Jonathan R. Swann
- Division of Computational and Systems Medicine, Department of Surgery and
Cancer, Imperial College London, United Kingdom
| | - Richard L. Guerrant
- Division of Infectious Diseases and International Health, Department of
Medicine, University of Virginia, Charlottesville, Virginia, United States of
America
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45
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Camilleri M, Sellin JH, Barrett KE. Pathophysiology, Evaluation, and Management of Chronic Watery Diarrhea. Gastroenterology 2017; 152:515-532.e2. [PMID: 27773805 PMCID: PMC5285476 DOI: 10.1053/j.gastro.2016.10.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/21/2016] [Accepted: 10/11/2016] [Indexed: 02/08/2023]
Abstract
Chronic watery diarrhea poses a diagnostic and therapeutic challenge and is often a disabling condition for patients. Although acute diarrhea is likely to be caused by infection, the causes of chronic diarrhea (>4 weeks in duration) are more elusive. We review the pathophysiology, diagnosis, and treatment of chronic diarrhea. Drawing on recent insights into the molecular mechanisms of intestinal epithelial transport and barrier function, we discuss how diarrhea can result from a decrease in luminal solute absorption, an increase in secretion, or both, as well as derangements in barrier properties. We also describe the various extraepithelial factors that activate diarrheal mechanisms. Finally, clinical evaluation and tests used in the assessment of patients presenting with chronic diarrhea are reviewed, and an algorithm guiding therapeutic decisions and pharmacotherapy is presented.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research, Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
| | - Joseph H. Sellin
- Division of Gastroenterology, Department of Medicine, Baylor College of Medicine, Houston, TX
| | - Kim E. Barrett
- Division of Gastroenterology, Department of Medicine, University of California, San Diego, La Jolla, CA
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46
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Abstract
Mucosal barriers separate self from non-self and are essential for life. These barriers, which are the first line of defense against external pathogens, are formed by epithelial cells and the substances they secrete. Rather than an absolute barrier, epithelia at mucosal surfaces must allow selective paracellular flux that discriminates between solutes and water while preventing the passage of bacteria and toxins. In vertebrates, tight junctions seal the paracellular space; flux across the tight junction can occur through two distinct routes that differ in selectivity, capacity, molecular composition and regulation. Dysregulation of either pathway can accompany disease. A third, tight-junction-independent route that reflects epithelial damage can also contribute to barrier loss during disease. In this Cell Science at a Glance article and accompanying poster, we present current knowledge on the molecular components and pathways that establish this selectively permeable barrier and the interactions that lead to barrier dysfunction during disease.
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Affiliation(s)
- Marion M France
- Department of Medicine (Gastroenterology, Hepatology, and Endoscopy), Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
| | - Jerrold R Turner
- Department of Medicine (Gastroenterology, Hepatology, and Endoscopy), Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 20 Shattuck St, TH1428, Boston, MA 02115, USA
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47
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Allain T, Amat CB, Motta JP, Manko A, Buret AG. Interactions of Giardia sp. with the intestinal barrier: Epithelium, mucus, and microbiota. Tissue Barriers 2017; 5:e1274354. [PMID: 28452685 DOI: 10.1080/21688370.2016.1274354] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Understanding how intestinal enteropathogens cause acute and chronic alterations has direct animal and human health perspectives. Significant advances have been made on this field by studies focusing on the dynamic crosstalk between the intestinal protozoan parasite model Giardia duodenalis and the host intestinal mucosa. The concept of intestinal barrier function is of the highest importance in the context of many gastrointestinal diseases such as infectious enteritis, inflammatory bowel disease, and post-infectious gastrointestinal disorders. This crucial function relies on 3 biotic and abiotic components, first the commensal microbiota organized as a biofilm, then an overlaying mucus layer, and finally the tightly structured intestinal epithelium. Herein we review multiple strategies used by Giardia parasite to circumvent these 3 components. We will summarize what is known and discuss preliminary observations suggesting how such enteropathogen directly and/ or indirectly impairs commensal microbiota biofilm architecture, disrupts mucus layer and damages host epithelium physiology and survival.
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Affiliation(s)
- Thibault Allain
- a Department of Biological Sciences , University of Calgary , Calgary , AB , Canada.,b Inflammation Research Network, University of Calgary , Calgary , AB , Canada.,c Host-Parasite Interactions, University of Calgary , Calgary , AB , Canada
| | - Christina B Amat
- a Department of Biological Sciences , University of Calgary , Calgary , AB , Canada.,b Inflammation Research Network, University of Calgary , Calgary , AB , Canada.,c Host-Parasite Interactions, University of Calgary , Calgary , AB , Canada
| | - Jean-Paul Motta
- a Department of Biological Sciences , University of Calgary , Calgary , AB , Canada.,b Inflammation Research Network, University of Calgary , Calgary , AB , Canada.,c Host-Parasite Interactions, University of Calgary , Calgary , AB , Canada
| | - Anna Manko
- a Department of Biological Sciences , University of Calgary , Calgary , AB , Canada.,b Inflammation Research Network, University of Calgary , Calgary , AB , Canada.,c Host-Parasite Interactions, University of Calgary , Calgary , AB , Canada
| | - André G Buret
- a Department of Biological Sciences , University of Calgary , Calgary , AB , Canada.,b Inflammation Research Network, University of Calgary , Calgary , AB , Canada.,c Host-Parasite Interactions, University of Calgary , Calgary , AB , Canada
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The Microbiota Contributes to CD8+ T Cell Activation and Nutrient Malabsorption following Intestinal Infection with Giardia duodenalis. Infect Immun 2016; 84:2853-60. [PMID: 27456829 DOI: 10.1128/iai.00348-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/18/2016] [Indexed: 12/19/2022] Open
Abstract
Giardia duodenalis is a noninvasive luminal pathogen that impairs digestive function in its host in part by reducing intestinal disaccharidase activity. This enzyme deficiency has been shown in mice to require CD8(+) T cells. We recently showed that both host immune responses and parasite strain affected disaccharidase levels during murine giardiasis. However, high doses of antibiotics were used to facilitate infections in that study, and we therefore decided to systematically examine the effects of antibiotic use on pathogenesis and immune responses in the mouse model of giardiasis. We found that antibiotic treatment did not overtly increase the parasite burden but significantly limited the disaccharidase deficiency observed in infected mice. Moreover, while infected mice had more activated CD8(+) αβ T cells in the small intestinal lamina propria, this increase was absent in antibiotic-treated mice. Infection also led to increased numbers of CD4(+) αβ T cells in the lamina propria and activation of T cell receptor γδ-expressing intraepithelial lymphocytes (IEL), but these changes were not affected by antibiotics. Finally, we show that activated CD8(+) T cells express gamma interferon (IFN-γ) and granzymes but that granzymes are not required for sucrase deficiency. We conclude that CD8(+) T cells become activated in giardiasis through an antibiotic-sensitive process and contribute to reduced sucrase activity. These are the first data directly demonstrating activation of CD8(+) T cells and γδ T cells during Giardia infections. These data also demonstrate that disruption of the intestinal microbiota by antibiotic treatment prevents pathological CD8(+) T cell activation in giardiasis.
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49
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Emery SJ, Lacey E, Haynes PA. Quantitative proteomics in Giardia duodenalis —Achievements and challenges. Mol Biochem Parasitol 2016; 208:96-112. [DOI: 10.1016/j.molbiopara.2016.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/13/2016] [Accepted: 07/16/2016] [Indexed: 12/31/2022]
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50
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Buret AG. Enteropathogen-Induced Microbiota Biofilm Disruptions and Post-Infectious Intestinal Inflammatory Disorders. CURRENT TROPICAL MEDICINE REPORTS 2016. [DOI: 10.1007/s40475-016-0079-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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