The impact of gut microbiota changes on the intestinal mucus barrier in burned mice: a study using 16S rRNA and metagenomic sequencing

Abstract

Background: The gut microbiota is a complex ecosystem that plays a critical role in human health and disease. However, the relationship between gut microbiota and intestinal damage caused by burns is not well understood. The intestinal mucus layer is crucial for maintaining intestinal homeostasis and providing a physiological barrier against bacterial invasion. This study aims to investigate the impact of gut microbiota on the synthesis and degradation of intestinal mucus after burns and explore potential therapeutic targets for burn injury. Methods: A modified histopathological grading system was employed to investigate the effects of burn injury on colon tissue and the intestinal mucus barrier in mice. Subsequently, 16S ribosomal RNA sequencing was used to analyze alterations in the gut microbiota at days 1–10 post-burn. Based on this, metagenomic sequencing was conducted on samples collected at days 1, 5 and 10 to investigate changes in mucus-related microbiota and explore potential underlying mechanisms. Results: Our findings showed that the mucus barrier was disrupted and that bacterial translocation occurred on day 3 following burn injury in mice. Moreover, the gut microbiota in mice was significantly disrupted from days 1 to 3 following burn injury, but gradually recovered to normal as the disease progressed. Specifically, there was a marked increase in the abundance of symbiotic and pathogenic bacteria associated with mucin degradation on day 1 after burns, but the abundance returned to normal on day 5. Conversely, the abundance of probiotic bacteria associated with mucin synthesis changed in the opposite direction. Further analysis revealed that after a burn injury, bacteria capable of degrading mucus may utilize glycoside hydrolases, flagella and internalins to break down the mucus layer, while bacteria that synthesize mucus may help restore the mucus layer by promoting the production of short-chain fatty acids. Conclusions: Burn injury leads to disruption of colonic mucus barrier and dysbiosis of gut microbiota. Some commensal and pathogenic bacteria may participate in mucin degradation via glycoside hydrolases, flagella, internalins, etc. Probiotics may provide short-chain fatty acids (particularly butyrate) as an energy source for stressed intestinal epithelial cells, promote mucin synthesis and accelerate repair of mucus layer.

Keywords

Burn injury / Gut microbiota / Intestinal mucus / 16S rRNA / Metagenomic sequencing

References

[1] Lozupone CA, Stombaugh JI, Gordon JI, Jansson JK, Knight R. Diversity, stability and resilience of the human gut microbiota. Nature. 2012; 489: 220-30.

[2] Yang XX, Guo YX, Chen C, Shao B, Zhao LY, Zhou QB, et al. Interaction between intestinal microbiota and tumour immunity in the tumour microenvironment. Immunology. 2021; 164: 476-93.

[3] Tilg H, Adolph TE, Gerner RR, Moschen AR. The intestinal microbiota in colorectal cancer. Cancer Cell. 2018; 33: 954-64.

[4] Aron-Wisnewsky J, Warmbrunn MV, Nieuwdorp M, Clément K. Metabolism and metabolic disorders and the microbiome: the intestinal microbiota associated with obesity, lipid metabolism, and metabolic health-pathophysiology and therapeutic strategies. Gastroenterology. 2021; 160: 573-99.

[5] Ma Q, Xing C, Long W, Wang HY, Liu Q, Wang RF. Impact of microbiota on central nervous system and neurological diseases: the gut-brain axis. J Neuroinflammation. 2019; 16: 53.

[6] Weingarden AR, Vaughn BP. Intestinal microbiota, fecal microbiota transplantation, and inflammatory bowel disease. Gut Microbes. 2017; 8: 238-52.

[7] Niu M, Chen P. Crosstalk between gut microbiota and sepsis. Burns. Trauma. 2021; 9: tkab036.

[8] Feng Y, Huang Y, Wang Y, Wang P, Wang F. Severe burn injury alters intestinal microbiota composition and impairs intestinal barrier in mice. Burns Trauma. 2019; 7: 20.

[9] Paone P, Cani PD.Mucus barrier, mucins and gut microbiota: the expected slimy partners? Gut. 2020; 69: 2232-43.

[10] Zhao Q, Maynard CL. Mucus, commensals, and the immune system. Gut Microbes. 2022; 14: 2041342.

[11] Hansson GC.Mucins and the microbiome. Annu Rev Biochem. 2020; 89: 769-93.

[12] Cornick S, Tawiah A, Chadee K. Roles and regulation of the mucus barrier in the gut. Tissue Barriers. 2015; 3:e982426.

[13] Pereira FC, Berry D. Microbial nutrient niches in the gut. Environ Microbiol. 2017; 19: 1366-78.

[14] Johansson ME, Sjövall H, Hansson GC. The gastrointestinal mucus system in health and disease. Nat Rev Gastroenterol Hepatol. 2013; 10: 352-61.

[15] Martens EC, Neumann M, Desai MS. Interactions of commensal and pathogenic microorganisms with the intestinal mucosal barrier. Nat Rev Microbiol. 2018; 16: 457-70.

[16] Ahl D, Liu H, Schreiber O, Roos S, Phillipson M, Holm L. Lactobacillus reuteri increases mucus thickness and ameliorates dextran sulphate sodium-induced colitis in mice. Acta Physiol. 2016; 217: 300-10.

[17] Bene KP, Kavanaugh DW, Leclaire C, Gunning AP, MacKenzie DA, Wittmann A, et al. Lactobacillus reuteri surface mucus adhesins upregulate inflammatory responses through interactions with innate C-type lectin receptors. Front Microbiol. 2017; 8: 321.

[18] Ouwerkerk JP, de Vos WM, Belzer C. Glycobiome: bacteria and mucus at the epithelial interface. Best Pract Res Clin Gastroenterol. 2013; 27: 25-38.

[19] Everard A, Belzer C, Geurts L, Ouwerkerk JP, Druart C, Bindels LB, et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity. Proc Natl Acad Sci U S A. 2013; 110: 9066-71.

[20] Beckmann N, Pugh AM, Caldwell CC. Burn injury alters the intestinal microbiome’s taxonomic composition and functional gene expression. PLoS One. 2018; 13: e0205307.

[21] Earley ZM, Akhtar S, Green SJ, Naqib A, Khan O, Cannon AR, et al. Burn injury alters the intestinal microbiome and increases gut permeability and bacterial translocation. PLoS One. 2015; 10: e0129996.

[22] Corcione S, Lupia T, De Rosa FG. Microbiome in the setting of burn patients: implications for infections and clinical outcomes. Burns Trauma. 2020; 8: tkaa033.

[23] Gilpin DA.Calculation of a new Meeh constant and experimental determination of burn size. Burns. 1996; 22: 607-11.

[24] Wu D, Su S, Zha X, Wei Y, Yang G, Huang Q, et al. Glutamine promotes O-GlcNAcylation of G6PD and inhibits AGR2 S-glutathionylation to maintain the intestinal mucus barrier in burned septic mice. Redox Biol. 2023; 59: 102581.

[25] Juge N.Microbial adhesins to gastrointestinal mucus. Trends Microbiol. 2012; 20: 30-9.

[26] Deleu S, Machiels K, Raes J, Verbeke K, Vermeire S. Short chain fatty acids and its producing organisms: an overlooked therapy for IBD? EBioMedicine. 2021; 66: 103293.

[27] Liang L, Liu L, Zhou W, Yang C, Mai G, Li H, et al. Gut microbiota-derived butyrate regulates gut mucus barrier repair by activating the macrophage/WNT/ERK signaling pathway. Clin Sci. 2022; 136: 291-307.

[28] Etienne-Mesmin L, Chassaing B, Desvaux M, De Paepe K, Gresse R, Sauvaitre T, et al. Experimental models to study intestinal microbes-mucus interactions in health and disease. FEMS Microbiol Rev. 2019; 43: 457-89.

[29] Eckburg PB, Bik EM, Bernstein CN, Purdom E, Dethlefsen L, Sargent M, et al. Diversity of the human intestinal microbial flora. Science. 2005; 308: 1635-8.

[30] Qin J, Li R, Raes J, Arumugam M, Burgdorf KS, Manichanh C, et al. A human gut microbial gene catalogue established by metagenomic sequencing. Nature. 2010; 464: 59-65.

[31] Belzer C, Chia LW, Aalvink S, Chamlagain B, Piironen V, Knol J, et al. Microbial metabolic networks at the mucus layer lead to diet-independent butyrate and vitamin B12 production by intestinal symbionts. MBio. 2017; 8: e00770-17.

[32] Shin NR, Lee JC, Lee HY, Kim MS, Whon TW, Lee MS, et al. An increase in the Akkermansia spp. population induced by metformin treatment improves glucose homeostasis in diet-induced obese mice. Gut. 2014; 63: 727-35.

[33] Png CW, Lindén SK, Gilshenan KS, Zoetendal EG, McSweeney CS, Sly LI, et al. Mucolytic bacteria with increased prevalence in IBD mucosa augment in vitro utilization of mucin by other bacteria. Am J Gastroenterol. 2010; 105: 2420-8.

[34] Hayase E, Hayase T, Jamal MA, Miyama T, Chang CC, Ortega MR, et al. Mucus-degrading Bacteroides link carbapenems to aggravated graft-versus-host disease. Cell. 2022; 185: 3705-3719.e14.

[35] Huang JY, Lee SM, Mazmanian SK. The human commensal Bacteroides fragilis binds intestinal mucin. Anaerobe. 2011; 17: 137-41.

[36] Sheikh A, Wangdi T, Vickers TJ, Aaron B, Palmer M, Miller MJ, et al. Enterotoxigenic Escherichia coli degrades the host MUC2 mucin barrier to facilitate critical pathogen-enterocyte interactions in human small intestine. Infect Immun. 2022; 90: e0057221.

[37] Crowther RS, Roomi NW, Fahim RE, Forstner JF. Vibrio cholerae metalloproteinase degrades intestinal mucin and facilitates enterotoxin-induced secretion from rat intestine. Biochim Biophys Acta. 1987; 924: 393-402.

[38] Ndeh D, Gilbert HJ. Biochemistry of complex glycan depolymerisation by the human gut microbiota. FEMS Microbiol Rev. 2018; 42: 146-64.

[39] Popowska M, Krawczyk-Balska A, Ostrowski R, Desvaux M. InlL from listeria monocytogenes is involved in biofilm formation and adhesion to mucin. Front Microbiol. 2017; 8: 660.

[40] Erdem AL, Avelino F, Xicohtencatl-Cortes J, Girón JA. Host protein binding and adhesive properties of H6 and H7 flagella of attaching and effacing Escherichia coli. J Bacteriol. 2007; 189: 7426-35.

[41] Li SC, Hsu WF, Chang JS, Shih CK. Combination of lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis shows a stronger anti-inflammatory effect than individual strains in HT-29 cells. Nutrients. 2019; 11: 969.

[42] Kumar M, Kissoon-Singh V, Coria AL, Moreau F, Chadee K. Probiotic mixture VSL#3 reduces colonic inflammation and improves intestinal barrier function in Muc2 mucin-deficient mice. Am J Physiol Gastrointest Liver Physiol. 2017; 312: G34-45.

[43] Blaak EE, Canfora EE, Theis S, Frost G, Groen AK, Mithieux G, et al. Short chain fatty acids in human gut and metabolic health. Benef Microbes. 2020; 11: 411-55.

[44] Lou X, Xue J, Shao R, Mo C, Wang F, Chen G. Postbiotics as potential new therapeutic agents for sepsis. Burns Trauma. 2023; 11: tkad022.

[45] Wang K, Zeng Q, Li X, Wang Y, Wang L, Sun W, et al. Efficacy of probiotics or synbiotics for critically ill adult patients: a systematic review and meta-analysis of randomized controlled trials. Burns Trauma. 2022; 10: tkac004.

[46] Martin-Gallausiaux C, Marinelli L, Blottière HM, Larraufie P, Lapaque N. SCFA: mechanisms and functional importance in the gut. Proc Nutr Soc. 2021; 80: 37-49. Koh A.

[47] De Vadder F, Kovatcheva-Datchary P, Bäckhed F. From dietary fiber to host physiology: short-chain fatty acids as key bacterial metabolites. Cell. 2016; 165: 1332-45.

[48] Hatayama H, Iwashita J, Abe T, et al. Butyrate stimulates MUC2 mucin promoter activity in human intestinal goblet cells. Biochem Biophys Res Commun. 2010; 399: 433-7.