Murine Fecal Microbiota Transplantation Alleviates Intestinal and Systemic Immune Responses in Campylobacter jejuni Infected Mice Harboring a Human Gut Microbiota.

Markus M Heimesaat,Stefan Bereswill,Katharina Mrazek

doi:10.3389/fimmu.2019.02272

Abstract

Human campylobacteriosis constitutes a zoonotic food-borne disease and a progressively rising health burden of significant socioeconomic impact. We have recently shown that conventional mice are protected from Campylobacter jejuni infection, which was not the case for human microbiota associated (hma) mice indicating that the host-specific gut microbiota composition primarily determines susceptibility to or resistance against C. jejuni infection. In our present preclinical intervention study we addressed whether gut microbiota changes in stably C. jejuni infected hma mice following murine fecal microbiota transplantation (mFMT) could alleviate pathogen-induced immune responses. To accomplish this, secondary abiotic C57BL/6 mice were generated by broad-spectrum antibiotic treatment, perorally reassociated with a complex human gut microbiota and challenged with C. jejuni by gavage. Seven days later C. jejuni infected hma mice were subjected to peroral mFMT on 3 consecutive days. Within a week post-mFMT fecal pathogenic burdens had decreased by two orders of magnitude, whereas distinct changes in the gut microbiota composition with elevated numbers of lactobacilli and bifidobacteria could be assessed. In addition, mFMT resulted in less C. jejuni induced apoptotic responses in colonic epithelia, reduced numbers of macrophages and monocytes as well as of T lymphocytes in the large intestinal mucosa and lamina propria and in less distinct intestinal pro-inflammatory cytokine secretion as compared to mock challenge. Strikingly, inflammation dampening effects of mFMT were not restricted to the intestinal tract, but could also be observed systemically as indicated by elevated serum concentrations of pro-inflammatory cytokines such as TNF-α, IL-12p70, and IL-6 in C. jejuni infected hma mice of the mock, but not the mFMT cohort. In conclusion, our preclinical mFMT intervention study provides evidence that changes in the gut microbiota composition which might be achieved by pre- or probiotic formulations may effectively lower intestinal C. jejuni loads, dampen both, pathogen-induced intestinal and systemic inflammatory sequelae and may represent a useful tool to treat continuous shedding of C. jejuni by asymptomatic carriers which is critical in the context of food production, hospitalization and immunosuppression.

Highlights

Human campylobacteriosis is among the four most prevalent global causes of diarrheal morbidities, whereas Campylobacter jejuni even constitutes the most common bacterial etiologic agents of human gastroenteritis with increasing prevalences worldwide [1, 2]
Conventionally colonized wildtype mice were protected from pathogenic colonization following peroral C. jejuni challenge even of high loads, the Abbreviations: CFU, colony forming units; D, d, day; FMT, fecal microbiota transplantation; Hma, human microbiota associated; HPF, high power field; IFN, interferon; IL, interleukin; mFMT, murine fecal microbiota transplantation; MLN, mesenteric lymph nodes; n.s, not significant; PBS, phosphate buffered saline; qRTPCR, quantitative real-time polymerase chain reaction; SPF, specific pathogen free; TNF, tumor necrosis factor
Mice with a human gut microbiota were perorally infected with C. jejuni on days 0 and 1 and subjected to murine fecal microbiota transplantation or received vehicle only on 3 consecutive days starting at day 7 post-infection (Figure 1)

Summary

INTRODUCTION

Human campylobacteriosis is among the four most prevalent global causes of diarrheal morbidities, whereas Campylobacter jejuni even constitutes the most common bacterial etiologic agents of human gastroenteritis with increasing prevalences worldwide [1, 2]. Reassociation of microbiota-depleted (i.e., secondary abiotic) mice with conventional murine gut microbiota via peroral fecal microbiota transplantation (FMT), could restore the colonization resistance against the pathogen, which was not the case when microbiota depleted mice were reassociated with fecal microbiota derived from human donors [15, 16]. Stable intestinal C. jejuni colonization of microbiota depleted as well as of human gut microbiota associated (hma) mice was further associated with pronounced pro-inflammatory immune responses mimicking key features of human campylobacteriosis [15]. In our present preclinical intervention study we addressed whether gut microbiota changes in stably infected C. jejuni mice harboring a human gut microbiota by peroral FMT derived from murine donors could lower intestinal pathogenic loads and dampen induced pro-inflammatory immune responses

Ethics Statement

Sampling Procedures

RESULTS

DISCUSSION

ETHICS STATEMENT