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Lurz E, Horne RG, Määttänen P, Wu RY, Botts SR, Li B, Rossi L, Johnson-Henry KC, Pierro A, Surette MG, Sherman PM. Vitamin B12 Deficiency Alters the Gut Microbiota in a Murine Model of Colitis. Front Nutr 2020; 7:83. [PMID: 32582756 PMCID: PMC7291859 DOI: 10.3389/fnut.2020.00083] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/07/2020] [Indexed: 12/15/2022] Open
Abstract
Purpose: Inflammatory bowel disease (IBD) refers to a spectrum of autoimmune diseases, which result in chronic intestinal inflammation. Previous findings suggest a role for diet, nutrition and dysbiosis of the gut microbiota in both the development and progression of the condition. Vitamin B12 is a key cofactor of methionine synthase and is produced solely by microbes. Previous work links increased levels of homocysteine, a substrate of methionine synthase, MetH, to IBD indicating a potential role for vitamin B12 deficiency in intestinal injury and inflammation. This study assessed the role of vitamin B12 in shaping the gut microbiota and determining responses to intestinal injury using a reproducible murine model of colitis. Methods: The effects of vitamin B12 supplementation and deficiency were assessed in vivo; 3-week-old post-weanling C57Bl/6 mice were divided into three dietary treatment groups: (1) sufficient vitamin B12 (50 mg/Kg), (2) deficient vitamin B12 (0 mg/Kg) and (3) supplemented vitamin B12 (200 mg/Kg) for a period of 4 weeks. Intestinal injury was induced with 2% dextran sodium sulphate (DSS) via drinking water for 5 days. The impact of varying levels of dietary vitamin B12 on gut microbiota composition was assessed using 16S rRNA gene sequencing from fecal samples collected at day 0 and day 28 of the dietary intervention, and 7 days following induction of colitis on day 38, when blood and colonic tissues were also collected. Results: No significant alterations were found in the gut microbiota composition of disease-free animals in response to dietary interventions. By contrast, after DSS-induced colitis, >30 genera were significantly altered in vitamin B12 deficient mice. Altered B12 levels produced no significant effect on composite disease-activity scores; however, administration of a B12 deficient diet resulted in reduced DSS-induced epithelial tissue damage. Conclusions: Vitamin B12 supplementation does not alter the gut microbiota composition under healthy conditions, but does contribute to differential microbial responses and intestinal dysbiosis following the induction of experimental colitis.
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Affiliation(s)
- Eberhard Lurz
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Division of Gastroenterology, Hepatology and Nutrition, Department of Paediatrics, Toronto, ON, Canada
| | - Rachael G Horne
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Pekka Määttänen
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Richard Y Wu
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Steven R Botts
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Bo Li
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Laura Rossi
- Department of Medicine, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | | | - Agostino Pierro
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Division of General and Thoracic Surgery, Hospital for Sick Children, Toronto, ON, Canada
| | - Michael G Surette
- Department of Medicine, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.,Farncombe Family Digestive Health Institute, McMaster University, Hamilton, ON, Canada
| | - Philip M Sherman
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Division of Gastroenterology, Hepatology and Nutrition, Department of Paediatrics, Toronto, ON, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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2
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Määttänen P, Lurz E, Botts SR, Wu RY, Robinson SC, Yeung CW, Colas R, Li B, Johnson-Henry KC, Surette ME, Dalli J, Sherman PM. Plant- and Fish-Derived n-3 PUFAs Suppress Citrobacter Rodentium-Induced Colonic Inflammation. Mol Nutr Food Res 2020; 64:e1900873. [PMID: 31945799 DOI: 10.1002/mnfr.201900873] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 12/05/2019] [Indexed: 02/06/2023]
Abstract
SCOPE Marine-derived n-3 PUFAs may ameliorate inflammation associated with inflammatory bowel diseases. Plant-derived n-3 PUFAs are thought to be inferior owing to shorter chain lengths. The aim of this study is to compare the impact of plant- and fish-derived PUFAs on murine colitis. METHODS AND RESULTS C57BL/6 mice are fed high fat (36% kcal) diets with either 2.5% w/w sunflower oil (SO), flaxseed oil (FSO), ahiflower oil (AO), or fish oil (FO). After 4 weeks, mice are orogastrically challenged with Citrobacter rodentium (108 CFU) or sham gavaged. Fecal shedding is assayed at 2, 7, 10, and 14 days post infection (PI), and fecal microbiota at 14 days PI. Colonic inflammation and lipid mediators are measured. Supplementation regulates intestinal inflammation with crypt lengths being 66, 73, and 62 ±17 µm shorter (compared to SO) for FSO, AO, and FO respectively, p < 0.01. FSO blunts pathogen shedding at the peak of infection and FSO and AO both enhance fecal microbial diversity. FO attenuates levels of lipoxin and leukotriene B4 while plant oils increase pro-resolving mediator concentrations including D, E, and T-series resolvins. CONCLUSION Plant and fish n-3 PUFAs attenuate colitis-induced inflammation while exhibiting characteristic pro-resolving lipid mediator metabolomes. Plant oils additionally promote microbial diversity.
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Affiliation(s)
- Pekka Määttänen
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Biology Department, Burman University, Lacombe, Alberta, T4L 2E5, Canada
| | - Eberhard Lurz
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Division of Gastroenterology, Hepatology and Nutrition, von Haunersches Kinderspital, Ludwig-Maximillians-University LMU, Munich, 80539, Germany
| | - Steven R Botts
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Richard Y Wu
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5S 1A1, Canada
| | - Shaiya C Robinson
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - C William Yeung
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Romain Colas
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - Bo Li
- Division of General and Thoracic Surgery, The Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Kathene C Johnson-Henry
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada
| | - Marc E Surette
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, E1A 3E9, Canada
| | - Jesmond Dalli
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK.,Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, London, E1 4NS, UK
| | - Philip M Sherman
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, M5G 1X8, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5S 1A1, Canada.,Faculty of Dentistry, University of Toronto, Toronto, Ontario, M5S 1A1, Canada
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3
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Wu RY, Li B, Koike Y, Määttänen P, Miyake H, Cadete M, Johnson-Henry KC, Botts SR, Lee C, Abrahamsson TR, Landberg E, Pierro A, Sherman PM. Human Milk Oligosaccharides Increase Mucin Expression in Experimental Necrotizing Enterocolitis. Mol Nutr Food Res 2018; 63:e1800658. [PMID: 30407734 DOI: 10.1002/mnfr.201800658] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/29/2018] [Indexed: 12/29/2022]
Abstract
SCOPE Necrotizing enterocolitis (NEC) is a leading cause of morbidity and death in preterm infants, occurring more often in formula-fed than breastfed infants. Studies in both rats and humans show that human milk oligosaccharides (HMOs) lower the incidence of NEC, but the mechanism underlying such protection is currently unclear. METHODS AND RESULTS By extracting HMOs from pooled human breastmilk, the impact of HMOs on the intestinal mucin levels in a murine model of NEC are investigated. To confirm the results, the findings are validated by exposing human intestinal epithelial cells and intestinal organoids to HMOs and evaluated for mucin expression. HMO-gavage to pups increases Muc2 levels and decreases intestinal permeability to macromolecular dextran. HMO-treated cells have increased Muc2 expression, decreased bacterial attachment and dextran permeability during challenge by enteric pathogens. To identify the mediators involved in HMO induction of mucins, it is demonstrated that HMOs directly induce the expression of chaperone proteins including protein disulfide isomerase (PDI). Suppression of PDI activity removes the protective effects of HMOs on barrier function in vitro as well as NEC protection in vivo. CONCLUSIONS Taken together, the results provide insights to the possible mechanisms by which HMOs protect the neonatal intestine through upregulation of mucins.
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Affiliation(s)
- Richard You Wu
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Bo Li
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yuhki Koike
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Pekka Määttänen
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hiromu Miyake
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Marissa Cadete
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kathene C Johnson-Henry
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Steven R Botts
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carol Lee
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Thomas R Abrahamsson
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Eva Landberg
- Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Agostino Pierro
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Division of General and Thoracic Surgery, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Philip M Sherman
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada.,Faculty of Dentistry, University of Toronto, Toronto, Canada
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Määttänen P, Lurz E, Botts SR, Wu RY, Yeung CW, Li B, Abiff S, Johnson-Henry KC, Lepp D, Power KA, Pierro A, Surette ME, Sherman PM. Ground flaxseed reverses protection of a reduced-fat diet against Citrobacter rodentium-induced colitis. Am J Physiol Gastrointest Liver Physiol 2018; 315:G788-G798. [PMID: 30095298 DOI: 10.1152/ajpgi.00101.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Flaxseed is high in ω-3 polyunsaturated fatty acids, fiber, and lignans known to lower cholesterol levels. However, its use for prevention or treatment of inflammatory bowel diseases has yielded mixed results, perhaps related to dietary interactions. In this study, we evaluated the impact of ground flaxseed supplementation on the severity of Citrobacter rodentium-induced colitis in the setting of either a high-fat (HF, ~36%kcal) or reduced-fat (RF, ~12%kcal) diet. After weaning, C57BL/6 mice ( n = 8-15/treatment) were fed ground flaxseed (7 g/100 g diet) with either HF (HF Flx) or RF (RF Flx) diets for 4 wk before infection with C. rodentium or sham gavage. Weight changes, mucosal inflammation, pathogen burden, gut microbiota composition, tissue polyunsaturated fatty acids, and cecal short-chain fatty acids were compared over a 14-day infection period. The RF diet protected against C. rodentium-induced colitis, whereas the RF Flx diet increased pathogen burden, exacerbated gut inflammation, and promoted gut dysbiosis. When compared with the RF diet, both HF and HF Flx diets resulted in more severe pathology in response to C. rodentium infection. Our findings demonstrate that although an RF diet protected against C. rodentium-induced colitis and associated gut dysbiosis in mice, beneficial effects were diminished with ground flaxseed supplementation. NEW & NOTEWORTHY Our results demonstrate a strong protective effect of a reduced-fat diet against intestinal inflammation, dysbiosis, and pathogen burden during Citrobacter rodentium-induced colitis. However, ground flaxseed supplementation in the setting of a reduced-fat diet exacerbated colitis despite higher levels of intestinal n-3 polyunsaturated fatty acids and cecal short-chain fatty acids.
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Affiliation(s)
- Pekka Määttänen
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Eberhard Lurz
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Steven R Botts
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Richard Y Wu
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto , Toronto , Canada
| | - C William Yeung
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Bo Li
- Division of General and Thoracic Surgery, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Sumayyah Abiff
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Kathene C Johnson-Henry
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Dion Lepp
- Agriculture and Agri-Food Canada/Government of Canada , Guelph, Ontario , Canada
| | - Krista A Power
- School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa , Ottawa, Ontario , Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Hospital for Sick Children , Toronto, Ontario , Canada
| | - Marc E Surette
- Department of Chemistry and Biochemistry, Université de Moncton , Moncton, New Brunswick , Canada
| | - Philip M Sherman
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children , Toronto, Ontario , Canada.,Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto , Toronto , Canada
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Wu RY, Määttänen P, Napper S, Scruten E, Li B, Koike Y, Johnson-Henry KC, Pierro A, Rossi L, Botts SR, Surette MG, Sherman PM. Non-digestible oligosaccharides directly regulate host kinome to modulate host inflammatory responses without alterations in the gut microbiota. Microbiome 2017; 5:135. [PMID: 29017607 PMCID: PMC5635512 DOI: 10.1186/s40168-017-0357-4] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 09/28/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND Prebiotics are non-digestible food ingredients that enhance the growth of certain microbes within the gut microbiota. Prebiotic consumption generates immune-modulatory effects that are traditionally thought to reflect microbial interactions within the gut. However, recent evidence suggests they may also impart direct microbe-independent effects on the host, though the mechanisms of which are currently unclear. METHODS Kinome arrays were used to profile the host intestinal signaling responses to prebiotic exposures in the absence of microbes. Identified pathways were functionally validated in Caco-2Bbe1 intestinal cell line and in vivo model of murine endotoxemia. RESULTS We found that prebiotics directly regulate host mucosal signaling to alter response to bacterial infection. Intestinal epithelial cells (IECs) exposed to prebiotics are hyporesponsive to pathogen-induced mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-κB) activations, and have a kinome profile distinct from non-treated cells pertaining to multiple innate immune signaling pathways. Consistent with this finding, mice orally gavaged with prebiotics showed dampened inflammatory response to lipopolysaccharide (LPS) without alterations in the gut microbiota. CONCLUSIONS These findings provide molecular mechanisms of direct host-prebiotic interactions to support prebiotics as potent modulators of host inflammation.
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Affiliation(s)
- Richard Y. Wu
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Pekka Määttänen
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
- Biology Department, Burman University, Lacombe, AB Canada
| | - Scott Napper
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, SK Canada
- Department of Biochemistry, University of Saskatchewan, Saskatoon, SK Canada
| | - Erin Scruten
- Vaccine and Infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatoon, SK Canada
| | - Bo Li
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, ON Canada
| | - Yuhki Koike
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, ON Canada
| | - Kathene C. Johnson-Henry
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
| | - Agostino Pierro
- Physiology and Experimental Medicine, Research Institute, Hospital for Sick Children, Toronto, ON Canada
- Division of General and Thoracic Surgery, Hospital for Sick Children, Toronto, ON Canada
| | - Laura Rossi
- Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON Canada
| | - Steven R. Botts
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
| | - Michael G. Surette
- Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON Canada
| | - Philip M. Sherman
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8 Canada
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Faculty of Dentistry, University of Toronto, Toronto, ON Canada
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Hock A, Miyake H, Li B, Lee C, Ermini L, Koike Y, Chen Y, Määttänen P, Zani A, Pierro A. Breast milk-derived exosomes promote intestinal epithelial cell growth. J Pediatr Surg 2017; 52:755-759. [PMID: 28188035 DOI: 10.1016/j.jpedsurg.2017.01.032] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/23/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND Breast milk administration prevents necrotizing enterocolitis (NEC). However, the mechanism remains unclear. Exosomes are cell-derived vesicles highly present in human milk and regulate intercellular signaling, inflammation, and immune response. We hypothesized that milk-derived exosomes beneficially affect intestinal epithelial cells. METHODS Rat milk was collected, and exosomes were isolated using ExoQuick reagent and visualized by Nanoparticle Tracking Analysis. Protein was extracted from encapsulating exosomes, and concentration was measured. 2×104 intestinal epithelial cells (IEC-18) were treated for five hours with 0.5-μg/μl exosomes, an equal volume of exosome-free milk, or control solution (PBS). IEC-18 viability was measured using a colorimetric assay (MTT), and gene expression was analyzed by qRT-PCR. Data were compared using one-way ANOVA with Bonferroni post-test. RESULTS Rat milk was collected, and exosome isolation was confirmed. Compared to control, treatment with exosomes significantly increased IEC viability, proliferation, and stem cell activity (all p<0.05). However, administration of exosome-free milk had less significant effects. CONCLUSIONS Rat milk-derived exosomes promote IEC viability, enhance proliferation, and stimulate intestinal stem cell activity. These findings provide insight into the mechanism of action of breast milk in the intestines. Exosome administration is a promising prevention method for infants at risk of developing NEC when breastfeeding is not tolerated.
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Affiliation(s)
- Alison Hock
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Hiromu Miyake
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Bo Li
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Carol Lee
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Leonardo Ermini
- Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Yuhki Koike
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Yong Chen
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Pekka Määttänen
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Augusto Zani
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada; Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Physiology and Experimental Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada.
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Vong L, Pinnell LJ, Määttänen P, Yeung CW, Lurz E, Sherman PM. Selective enrichment of commensal gut bacteria protects against Citrobacter rodentium-induced colitis. Am J Physiol Gastrointest Liver Physiol 2015; 309:G181-92. [PMID: 26067845 DOI: 10.1152/ajpgi.00053.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/31/2015] [Indexed: 01/31/2023]
Abstract
The intestinal microbiota plays a key role in shaping the host immune system. Perturbation of gut microbial composition, termed dysbiosis, is associated with an increased susceptibility to intestinal pathogens and is a hallmark of a number of inflammatory, metabolic, and infectious diseases. The prospect of mining the commensal gut microbiota for bacterial strains that can impact immune function represents an attractive strategy to counteract dysbiosis and resulting disease. In this study, we show that selective enrichment of commensal gut lactobacilli protects against the murine pathogen Citrobacter rodentium, a well-characterized model of enteropathogenic and enterohemorrhagic Escherichia coli infection. The lactobacilli-enriched bacterial culture prevented the expansion of Gammaproteobacteria and Actinobacteria and was associated with improved indexes of epithelial barrier function (dextran flux), transmissible crypt hyperplasia, and tissue inflammatory cytokine levels. Moreover, cultivation of gut bacteria from Citrobacter rodentium-infected mice reveals the differential capacity of bacterial subsets to mobilize neutrophil oxidative burst and initiate the formation of weblike neutrophil extracellular traps. Our findings highlight the beneficial effects of a lactobacilli-enriched commensal gut microenvironment and, in the context of an intestinal barrier breach, the ability of neutrophils to immobilize both commensal and pathogenic bacteria.
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Affiliation(s)
- Linda Vong
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and
| | - Lee J Pinnell
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and
| | - Pekka Määttänen
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and
| | - C William Yeung
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and
| | - Eberhard Lurz
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and
| | - Philip M Sherman
- Cell Biology Program, Research Institute, Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; and Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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Taschuk R, Marciniuk K, Määttänen P, Madampage C, Hedlin P, Potter A, Lee J, Cashman NR, Griebel PJ, Napper S. Safety, specificity and immunogenicity of a PrP(Sc)-specific prion vaccine based on the YYR disease specific epitope. Prion 2015; 8:51-9. [PMID: 24509522 DOI: 10.4161/pri.27962] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prions are a novel form of infectivity based on the misfolding of a self-protein (PrP(C)) into a pathological, infectious isomer (PrP(Sc)). The current uncontrolled spread of chronic wasting disease in cervids, coupled with the demonstrated zoonotic nature of select livestock prion diseases, highlights the urgent need for disease management tools. While there is proof-of-principle evidence for a prion vaccine, these efforts are complicated by the challenges and risks associated with induction of immune responses to a self-protein. Our priority is to develop a PrP(Sc)-specific prion vaccine based on epitopes that are uniquely exposed upon misfolding. These disease specific epitopes (DSEs) have the potential to enable specific targeting of the pathological species through immunotherapy. Here we review outcomes of the translation of a prion DSE into a PrP(Sc)-specific vaccine based on the criteria of immunogenicity, safety and specificity.
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Madampage CA, Marciniuk K, Määttänen P, Cashman NR, Potter A, Lee JS, Napper S. Nanopore analysis reveals differences in structural stability of ovine PrP(C) proteins corresponding to scrapie susceptible (VRQ) and resistance (ARR) genotypes. Prion 2014; 7:511-9. [PMID: 24401607 DOI: 10.4161/pri.27502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Species, as well as individuals within species, have unique susceptibilities to prion infection that are likely based on sequence differences in cellular prion protein (PrP(C)). Species barriers to transmission also reflect PrP(C) sequence differences. Defining the structure-activity relationship of PrP(C)/PrP(Sc) with respect to infectivity/susceptibility will benefit disease understanding and assessment of transmission risks. Here, nanopore analysis is employed to investigate genotypes of sheep PrP(C) corresponding to differential susceptibilities to scrapie infection. Under non-denaturing conditions scrapie resistant (ARR) and susceptible (VRQ) genotypes display similar, type I (bumping) predominant event profiles, suggesting a conserved folding pattern. Under increasingly denaturing conditions both proteins shift to type II (intercalation/translocation) events but with different sensitivities to unfolding. Specifically, when pre-incubated in 2M Gdn-HCl, the VRQ variant had more of type II events as compared with the ARR protein, suggesting a more flexible unfolding pattern. Addition of PrP(Sc)-specific polyclonal antibody (YML) to the ARR variant, pre-incubated in 2M Gdn-HCl, reduced the number of type II events with no clear intercalation/translocation peak, whereas for VRQ, type II events above blockades of 90 pA bound YML. A second PrP(Sc)-specific antibody (SN6b) to a different cryptic epitope reduced type II events for VRQ but not the ARR variant. Collectively, the event patterns associated with sequential denaturation, as well as interactions with PrP(Sc)-specific antibodies, support unique patterns and/or propensities of misfolding between the genotypes. Overall, nanopore analysis identifies intermediate conformations that occur during the unfolding pathways of ARR and VRQ genotypes and may help to understand the correlation of structural properties that induce protein misfolding.
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Affiliation(s)
- Claudia Avis Madampage
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada
| | - Kristen Marciniuk
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada
| | - Pekka Määttänen
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada
| | - Neil R Cashman
- University of British Columbia & Vancouver Coastal Health Research Institute; Vancouver, BC Canada
| | - Andrew Potter
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada
| | - Jeremy S Lee
- Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada
| | - Scott Napper
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada
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Trost B, Kindrachuk J, Määttänen P, Napper S, Kusalik A. PIIKA 2: an expanded, web-based platform for analysis of kinome microarray data. PLoS One 2013; 8:e80837. [PMID: 24312246 PMCID: PMC3843739 DOI: 10.1371/journal.pone.0080837] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 10/17/2013] [Indexed: 01/25/2023] Open
Abstract
Kinome microarrays are comprised of peptides that act as phosphorylation targets for protein kinases. This platform is growing in popularity due to its ability to measure phosphorylation-mediated cellular signaling in a high-throughput manner. While software for analyzing data from DNA microarrays has also been used for kinome arrays, differences between the two technologies and associated biologies previously led us to develop Platform for Intelligent, Integrated Kinome Analysis (PIIKA), a software tool customized for the analysis of data from kinome arrays. Here, we report the development of PIIKA 2, a significantly improved version with new features and improvements in the areas of clustering, statistical analysis, and data visualization. Among other additions to the original PIIKA, PIIKA 2 now allows the user to: evaluate statistically how well groups of samples cluster together; identify sets of peptides that have consistent phosphorylation patterns among groups of samples; perform hierarchical clustering analysis with bootstrapping; view false negative probabilities and positive and negative predictive values for t-tests between pairs of samples; easily assess experimental reproducibility; and visualize the data using volcano plots, scatterplots, and interactive three-dimensional principal component analyses. Also new in PIIKA 2 is a web-based interface, which allows users unfamiliar with command-line tools to easily provide input and download the results. Collectively, the additions and improvements described here enhance both the breadth and depth of analyses available, simplify the user interface, and make the software an even more valuable tool for the analysis of kinome microarray data. Both the web-based and stand-alone versions of PIIKA 2 can be accessed via http://saphire.usask.ca.
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Affiliation(s)
- Brett Trost
- Department of Computer Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
- * E-mail:
| | - Jason Kindrachuk
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Pekka Määttänen
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Scott Napper
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Anthony Kusalik
- Department of Computer Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Määttänen P, Taschuk R, Ross L, Marciniuk K, Bertram L, Potter A, Cashman NR, Napper S. PrP(Sc)-specific antibodies do not induce prion disease or misfolding of PrP(C) in highly susceptible Tga20 mice. Prion 2013; 7:434-9. [PMID: 24105298 DOI: 10.4161/pri.26639] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders caused by misfolding of a cellular protein PrP(C) into an infectious conformation PrP(Sc). Previously our group demonstrated induction of PrP(Sc)-specific antibodies with a SN6b vaccine that targets regions of the protein that are exposed upon misfolding. There are concerns that these antibodies could function as templates to promote misfolding and cause disease. To evaluate the consequences of prolonged exposure to PrP(Sc)-specific antibodies in a prion sensitized animal, tga20 mice were vaccinated with the SN6b vaccine. No clinical signs of disease were detected up to 255 d post-vaccination, and postmortem assay of brains and spleens revealed no proteinase-K resistant PrP. These results suggest that vaccinating against TSEs with the SN6b antigen is safe from the standpoint of prion disease induction.
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Affiliation(s)
| | - Ryan Taschuk
- VIDO-InterVac; University of Saskatchewan; Saskatoon, SK CA; School of Public Health; University of Saskatchewan; SK CA
| | - Li Ross
- Brain Research Center; University of British Columbia; Vancouver, BC CA
| | - Kristen Marciniuk
- VIDO-InterVac; University of Saskatchewan; Saskatoon, SK CA; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK CA
| | - Lisa Bertram
- Brain Research Center; University of British Columbia; Vancouver, BC CA
| | - Andrew Potter
- VIDO-InterVac; University of Saskatchewan; Saskatoon, SK CA
| | - Neil R Cashman
- Brain Research Center; University of British Columbia; Vancouver, BC CA
| | - Scott Napper
- VIDO-InterVac; University of Saskatchewan; Saskatoon, SK CA; School of Public Health; University of Saskatchewan; SK CA; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK CA
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Madampage CA, Määttänen P, Marciniuk K, Brownlie R, Andrievskaia O, Potter A, Cashman NR, Lee JS, Napper S. Binding of bovine T194A PrP(C) by PrP(Sc)-specific antibodies: potential implications for immunotherapy of familial prion diseases. Prion 2013; 7:301-11. [PMID: 23787697 DOI: 10.4161/pri.25148] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases that are based on the misfolding of a cellular prion protein (PrP(C)) into an infectious, pathological conformation (PrP(Sc)). There is proof-of-principle evidence that a prion vaccine is possible but this is tempered with concerns of the potential dangers associated with induction of immune responses to a widely-expressed self-protein. By targeting epitopes that are specifically exposed upon protein misfolding, our group developed a vaccine that induces PrP(Sc)-specific antibody responses. Here we consider the ability of this polyclonal antibody (SN6b) to bind to a mutant of PrP(C) associated with spontaneous prion disease. Polyclonal antibodies were selected to mimic the vaccination outcome and also explore all possible protein conformations of the recombinant bovine prion protein with mutation T194A [bPrP(T194A)]. This mutant is a homolog of the human T183A mutation of PrP(C) that is associated with early onset of familial dementia. With nanopore analysis, under non-denaturing conditions, we observed binding of the SN6b antibody to bPrP(T194A). This interaction was confirmed through ELISAs as well as immunoprecipitation of the recombinant and cellularly expressed forms of bPrP(T194A). This interaction did not promote formation of a protease resistant conformation of PrP in vitro. Collectively, these findings support the disease-specific approach for immunotherapy of prion diseases but also suggest that the concept of conformation-specific immunotherapy may be complicated in individuals who are genetically predisposed to PrP(C) misfolding.
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Affiliation(s)
- Claudia A Madampage
- Vaccine and Infectious Disease Organization; University of Saskatchewan; Saskatoon, SK Canada; Department of Biochemistry; University of Saskatchewan; Saskatoon, SK Canada
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Jansen G, Määttänen P, Denisov AY, Scarffe L, Schade B, Balghi H, Dejgaard K, Chen LY, Muller WJ, Gehring K, Thomas DY. An interaction map of endoplasmic reticulum chaperones and foldases. Mol Cell Proteomics 2012; 11:710-23. [PMID: 22665516 DOI: 10.1074/mcp.m111.016550] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Chaperones and foldases in the endoplasmic reticulum (ER) ensure correct protein folding. Extensive protein-protein interaction maps have defined the organization and function of many cellular complexes, but ER complexes are under-represented. Consequently, chaperone and foldase networks in the ER are largely uncharacterized. Using complementary ER-specific methods, we have mapped interactions between ER-lumenal chaperones and foldases and describe their organization in multiprotein complexes. We identify new functional chaperone modules, including interactions between protein-disulfide isomerases and peptidyl-prolyl cis-trans-isomerases. We have examined in detail a novel ERp72-cyclophilin B complex that enhances the rate of folding of immunoglobulin G. Deletion analysis and NMR reveal a conserved surface of cyclophilin B that interacts with polyacidic stretches of ERp72 and GRp94. Mutagenesis within this highly charged surface region abrogates interactions with its chaperone partners and reveals a new mechanism of ER protein-protein interaction. This ability of cyclophilin B to interact with different partners using the same molecular surface suggests that ER-chaperone/foldase partnerships may switch depending on the needs of different substrates, illustrating the flexibility of multichaperone complexes of the ER folding machinery.
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Affiliation(s)
- Gregor Jansen
- Department of Biochemistry, McGill University, Montréal, Québec H3G 1Y6, Canada
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14
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Kozlov G, Bastos-Aristizabal S, Määttänen P, Rosenauer A, Zheng F, Killikelly A, Trempe JF, Thomas DY, Gehring K. Structural basis of cyclophilin B binding by the calnexin/calreticulin P-domain. J Biol Chem 2010; 285:35551-7. [PMID: 20801878 PMCID: PMC2975179 DOI: 10.1074/jbc.m110.160101] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/15/2010] [Indexed: 11/06/2022] Open
Abstract
Little is known about how chaperones in the endoplasmic reticulum are organized into complexes to assist in the proper folding of secreted proteins. One notable exception is the complex of ERp57 and calnexin that functions as part the calnexin cycle to direct disulfide bond formation in N-glycoproteins. Here, we report three new complexes composed of the peptidyl prolyl cis-trans-isomerase cyclophilin B and any of the lectin chaperones: calnexin, calreticulin, or calmegin. The 1.7 Å crystal structure of cyclophilin with the proline-rich P-domain of calmegin reveals that binding is mediated by the same surface that binds ERp57. We used NMR titrations and mutagenesis to measure low micromolar binding of cyclophilin to all three lectin chaperones and identify essential interfacial residues. The immunosuppressant cyclosporin A did not affect complex formation, confirming the functional independence of the P-domain binding and proline isomerization sites of cyclophilin. Our results reveal the P-domain functions as a unique protein-protein interaction domain and implicate a peptidyl prolyl isomerase as a new element in the calnexin cycle.
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Affiliation(s)
- Guennadi Kozlov
- Department of Biochemistry and Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada
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16
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Määttänen P, Gehring K, Bergeron JJM, Thomas DY. Protein quality control in the ER: the recognition of misfolded proteins. Semin Cell Dev Biol 2010; 21:500-11. [PMID: 20347046 DOI: 10.1016/j.semcdb.2010.03.006] [Citation(s) in RCA: 191] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/16/2010] [Accepted: 03/18/2010] [Indexed: 02/08/2023]
Abstract
The mechanism, in molecular terms of protein quality control, specifically of how the cell recognizes and discriminates misfolded proteins, remains a challenge. In the secretory pathway the folding status of glycoproteins passing through the endoplasmic reticulum is marked by the composition of the N-glycan. The different glycoforms are recognized by specialized lectins. The folding sensor UGGT acts as an unusual molecular chaperone and covalently modifies the Man9 N-glycan of a misfolded protein by adding a glucose moiety and converts it to Glc1Man9 that rebinds the lectin calnexin. However, further links between the folding status of a glycoprotein and the composition of the N-glycan are unclear. There is little unequivocal evidence for other proteins in the ER recognizing the N-glycan and also acting as molecular chaperones. Nevertheless, based upon a few examples, we suggest that this function is carried out by individual proteins in several different complexes. Thus, calnexin binds the protein disulfide isomerase ERp57, that acts upon Glc1Man9 glycoproteins. In another example the protein disulfide isomerase ERdj5 binds specifically to EDEM (which is probably a mannosidase) and a lectin OS9, and reduces the disulfide bonds of bound glycoproteins destined for ERAD. Thus the glycan recognition is performed by a lectin and the chaperone function performed by a specific partner protein that can recognize misfolded proteins. We predict that this will be a common arrangement of proteins in the ER and that members of protein foldase families such as PDI and PPI will bind specifically to lectins in the ER. Molecular chaperones BiP and GRp94 will assist in the folding of proteins bound in these complexes as well as in the folding of non-glycoproteins.
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Affiliation(s)
- Pekka Määttänen
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Kozlov G, Määttänen P, Schrag JD, Hura GL, Gabrielli L, Cygler M, Thomas DY, Gehring K. Structure of the noncatalytic domains and global fold of the protein disulfide isomerase ERp72. Structure 2009; 17:651-9. [PMID: 19446521 DOI: 10.1016/j.str.2009.02.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 02/03/2023]
Abstract
Protein disulfide isomerases are a family of proteins that catalyze the oxidation and isomerization of disulfide bonds in newly synthesized proteins in the endoplasmic reticulum. The family includes general enzymes such as PDI that recognize unfolded proteins, and others that are selective for specific classes of proteins. Here, we report the X-ray crystal structure of central non-catalytic domains of a specific isomerase, ERp72 (also called CaBP2 and protein disulfide-isomerase A4) from Rattus norvegicus. The structure reveals strong similarity to ERp57, a PDI-family member that interacts with the lectin-like chaperones calnexin and calreticulin but, unexpectedly, ERp72 does not interact with calnexin as shown by isothermal titration calorimetry and nuclear magnetic resonance (NMR) spectroscopy. Small-angle X-ray scattering (SAXS) of ERp72 was used to develop models of the full-length protein using both rigid body refinement and ab initio simulated annealing of dummy atoms. The two methods show excellent agreement and define the relative positions of the five thioredoxin-like domains of ERp72 and potential substrate or chaperone binding sites.
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Affiliation(s)
- Guennadi Kozlov
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montréal, Québec, Canada
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Abstract
Protein disulfide isomerase is the most abundant and best studied of the disulfide isomerases that catalyze disulfide bond formation in the endoplasmic reticulum, yet the specifics of how it binds substrate have been elusive. Protein disulfide isomerase is composed of four thioredoxin-like domains (abb'a'). Cross-linking studies with radiolabeled peptides and unfolded proteins have shown that it binds incompletely folded proteins primarily via its third domain, b'. Here, we determined the solution structure of the second and third domains of human protein disulfide isomerase (b and b', respectively) by triple-resonance NMR spectroscopy and molecular modeling. NMR titrations identified a large hydrophobic surface within the b' domain that binds unfolded ribonuclease A and the peptides mastoparan and somatostatin. Protein disulfide isomerase-catalyzed refolding of reduced ribonuclease A in vitro was inhibited by these peptides at concentrations equal to their affinity to the bb' fragment. Our findings provide a structural basis for previous kinetic and cross-linking studies which have shown that protein disulfide isomerase exhibits a saturable, substrate-binding site.
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