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Gerrick ER, Zlitni S, West PT, Carter MM, Mechler CM, Olm MR, Caffrey EB, Li JA, Higginbottom SK, Severyn CJ, Kracke F, Spormann AM, Sonnenburg JL, Bhatt AS, Howitt MR. Metabolic diversity in commensal protists regulates intestinal immunity and trans-kingdom competition. Cell 2024; 187:62-78.e20. [PMID: 38096822 DOI: 10.1016/j.cell.2023.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 08/01/2023] [Accepted: 11/14/2023] [Indexed: 01/05/2024]
Abstract
The microbiota influences intestinal health and physiology, yet the contributions of commensal protists to the gut environment have been largely overlooked. Here, we discover human- and rodent-associated parabasalid protists, revealing substantial diversity and prevalence in nonindustrialized human populations. Genomic and metabolomic analyses of murine parabasalids from the genus Tritrichomonas revealed species-level differences in excretion of the metabolite succinate, which results in distinct small intestinal immune responses. Metabolic differences between Tritrichomonas species also determine their ecological niche within the microbiota. By manipulating dietary fibers and developing in vitro protist culture, we show that different Tritrichomonas species prefer dietary polysaccharides or mucus glycans. These polysaccharide preferences drive trans-kingdom competition with specific commensal bacteria, which affects intestinal immunity in a diet-dependent manner. Our findings reveal unappreciated diversity in commensal parabasalids, elucidate differences in commensal protist metabolism, and suggest how dietary interventions could regulate their impact on gut health.
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Affiliation(s)
- Elias R Gerrick
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Soumaya Zlitni
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrick T West
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew M Carter
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Claire M Mechler
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Matthew R Olm
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elisa B Caffrey
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jessica A Li
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Steven K Higginbottom
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Christopher J Severyn
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Pediatrics, Division of Hematology/Oncology/Stem Cell Transplant and Regenerative Medicine Stanford University, Palo Alto, CA 94305, USA
| | - Frauke Kracke
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305, USA
| | - Alfred M Spormann
- Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305, USA; Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Justin L Sonnenburg
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Ami S Bhatt
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael R Howitt
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Gerrick ER, DeSchepper LB, Mechler CM, Joubert LM, Dunker F, Colston TJ, Howitt MR. Commensal protists in reptiles display flexible host range and adaptation to ectothermic hosts. mBio 2023; 14:e0227323. [PMID: 37962346 PMCID: PMC10746265 DOI: 10.1128/mbio.02273-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 10/04/2023] [Indexed: 11/15/2023] Open
Abstract
IMPORTANCE Environmental factors like climate change and captive breeding can impact the gut microbiota and host health. Therefore, conservation efforts for threatened species may benefit from understanding how these factors influence animal microbiomes. Parabasalid protists are members of the mammalian microbiota that can modulate the immune system and impact susceptibility to infections. However, little is known about parabasalids in reptiles. Here, we profile reptile-associated parabasalids in wild and captive reptiles and find that captivity has minimal impact on parabasalid prevalence or diversity. However, because reptiles are cold-blooded (ectothermic), their microbiotas experience wider temperature fluctuation than microbes in warm-blooded animals. To investigate whether extreme weather patterns affect parabasalid-host interactions, we analyzed the gene expression in reptile-associated parabasalids and found that temperature differences significantly alter genes associated with host health. These results expand our understanding of parabasalids in this vulnerable vertebrate group and highlight important factors to be taken into consideration for conservation efforts.
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Affiliation(s)
- Elias R. Gerrick
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Leila B. DeSchepper
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Claire M. Mechler
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Lydia-Marie Joubert
- Cell Sciences Imaging Facility (CSIF), Stanford University, Stanford, California, USA
| | - Freeland Dunker
- Steinhart Aquarium, California Academy of Sciences, San Francisco, California, USA
| | | | - Michael R. Howitt
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
- Department of Microbiology, Stanford University School of Medicine, Stanford, California, USA
- Program in Immunology, Stanford University School of Medicine, Stanford, California, USA
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Gerrick ER, DeSchepper LB, Mechler CM, Joubert LM, Dunker F, Colston TJ, Howitt MR. Commensal protists in reptiles display flexible host range and adaptation to ectothermic hosts. bioRxiv 2023:2023.05.25.542353. [PMID: 37292851 PMCID: PMC10245904 DOI: 10.1101/2023.05.25.542353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Parabasalid protists recently emerged as keystone members of the mammalian microbiota with important effects on their host's health. However, the prevalence and diversity of parabasalids in wild reptiles and the consequences of captivity and other environmental factors on these symbiotic protists are unknown. Reptiles are ectothermic, and their microbiomes are subject to temperature fluctuations, such as those driven by climate change. Thus, conservation efforts for threatened reptile species may benefit from understanding how shifts in temperature and captive breeding influence the microbiota, including parabasalids, to impact host fitness and disease susceptibility. Here, we surveyed intestinal parabasalids in a cohort of wild reptiles across three continents and compared these to captive animals. Reptiles harbor surprisingly few species of parabasalids compared to mammals, but these protists exhibited a flexible host-range, suggesting specific adaptations to reptilian social structures and microbiota transmission. Furthermore, reptile-associated parabasalids are adapted to wide temperature ranges, although colder temperatures significantly altered the protist transcriptomes, with increased expression of genes associated with detrimental interactions with the host. Our findings establish that parabasalids are widely distributed in the microbiota of wild and captive reptiles and highlight how these protists respond to temperature swings encountered in their ectothermic hosts.
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Affiliation(s)
- Elias R Gerrick
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Leila B DeSchepper
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Claire M Mechler
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lydia-Marie Joubert
- Cell Sciences Imaging Facility (CSIF), Stanford University, Stanford, CA 94305, USA
| | - Freeland Dunker
- Steinhart Aquarium, California Academy of Science, San Francisco, CA 94118, USA
| | - Timothy J Colston
- Biology Department, University of Puerto Rico at Mayagüez, Call Box 9000, 00681-9000 Mayagüez, Puerto Rico
| | - Michael R Howitt
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Lead Contact
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Gologorsky MB, Mechler CM, Forgó E, Charville GW, Howitt MR. The abundance and morphology of human large intestinal goblet and tuft cells during chronic schistosomiasis. Parasite Immunol 2023; 45:e12981. [PMID: 37038837 DOI: 10.1111/pim.12981] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/23/2023] [Accepted: 03/24/2023] [Indexed: 04/12/2023]
Abstract
Schistosomiasis affects nearly 240 million people in predominately low- and middle-income countries and ranks second in the number of cases and socio-economic burden among all parasitic diseases. Despite the enormous burden posed by schistosomes, our understanding of how schistosomiasis impacts infected human tissues remains limited. Intestinal schistosomiasis in animal models leads to goblet cell hyperplasia, likely increasing mucus production and reflecting an intestinal type 2 immune response. However, it is unknown whether these same changes occur in schistosome-infected humans. Using immunofluorescence and light microscopy, we compared the abundance and morphology of goblet cells in patients diagnosed with schistosomiasis to uninfected controls. The mucin-containing vesicles in goblet cells from schistosome-infected patients were significantly larger (hypertrophic) than uninfected individuals, although goblet cell hyperplasia was absent in chronic human schistosomiasis. In addition, we examined tuft cells in the large intestinal epithelium of control and schistosome-infected patients. Tuft cell numbers expand during helminth infection in mice, but these cells have not been characterized in human parasite infections. We found no evidence of tuft cell hyperplasia during human schistosome infection. Thus, our study provides novel insight into schistosome-associated changes to the intestinal epithelium in humans, suggesting an increase in mucus production by large intestinal goblet cells but relatively minor effects on tuft cell numbers.
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Affiliation(s)
- Matthew B Gologorsky
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Claire M Mechler
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Erna Forgó
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Gregory W Charville
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
| | - Michael R Howitt
- Department of Pathology, Stanford University School of Medicine, Palo Alto, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California, USA
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