Biology subjects

Borneman, J.

Publications and source records attributed to Borneman, J..

5 recordsLinked to original sources

bioRxiv2024

Intestinal Epithelial PTPN2 Limits Pathobiont Colonization by Immune-Directed Antimicrobial Responses

Background and AimsLoss of activity of the inflammatory bowel disease (IBD) susceptibility gene, protein tyrosine phosphatase non-receptor type 2 (PTPN2), is associated with altered microbiome composition in both human subjects and mice. Further, expansion of the bacterial pathobiont, adherent- invasive E. coli (AIEC), is strongly linked to IBD pathogenesis. The mechanism by which intestinal epithelial cells (IEC) maintain equilibrium between commensal microbiota and immune cells to restrict invading pathobionts is poorly understood. Here, we investigated the role of IEC-specific PTPN2 in regulating AIEC colonization. MethodsTamoxifen-inducible, intestinal epithelial cell-specific Ptpn2 knockout mice (Ptpn2{Delta}IEC) and control Ptpn2fl/fl mice were infected with either non-invasive E. coli K12, or fluorescent-tagged mAIEC (mAIECred) for four consecutive days or administered PBS. Subsequently, bacterial colonization in mouse tissues was quantified. mRNA and protein expression were assayed in intestinal epithelial cells (IECs) or whole tissue lysates by PCR and Western blot. Tissue cytokine expression was determined by ELISA. Intestinal barrier function was determined by in vivo administration of 4 kDa FITC-dextran (FD4) or 70kDa Rhodamine-B dextran (RD70) fluorescent probes. Confocal microscopy was used to determine the localization of tight-junction proteins. ResultsPtpn2{Delta}IEC mice exhibited increased mAIECred - but not K12 - bacterial load in the distal colon compared to infected Ptpn2fl/fl mice. The higher susceptibility to mAIECred infection was associated with altered levels of antimicrobial peptide (AMPs). Ileal RNA expression of the alpha-defensin AMPs, Defa5 and Defa6, as well as MMP7, was significantly lower in Ptpn2{Delta}IEC vs. Ptpn2fl/fl mice, after mAIECred but not K12 infection. Further, we observed increased tight junction-regulated permeability determined by elevated in vivo FD4 but not RD70 permeability in Ptpn2{Delta}IEC-K12 mice compared to their respective controls. This effect was further exacerbated in Ptpn2{Delta}IEC mAIEC-infected mice. Further, Ptpn2{Delta}IEC mice displayed lower IL-22, IL-6, IL-17A cytokine expression post mAIEC infection compared to Ptpn2fl/fl controls. Recombinant IL-22 reversed the FD4 permeability defect and reduced bacterial burden in Ptpn2{Delta}IEC mice post mAIEC challenge. ConclusionOur findings highlight that intestinal epithelial PTPN2 is crucial for mucosal immunity and gut homeostasis by promoting anti-bacterial defense mechanisms involving coordinated epithelial-immune responses to restrict pathobiont colonization.

immunology↗

bioRxiv2023

Effect of Nivolumab therapy on Metastatic Lung Cancer in Human Microbiome

Nivolumab, a type of immunotherapy, has enhanced the 5-year survival of patients with renal cell cancer, melanoma, and lung cancer which is now mechanistically understood. However, relatively sparse information assesses its relationship with shaping the gut microbiome. We aimed to assess the degree to which nivolumab treatment contributes to alterations in the species composition of the colon in lung cancer patients undergoing nivolumab treatment. Our pilot study utilized stool samples of five lung cancer patients at Inland Hematology Oncology (IHO) before administration of nivolumab and three months after initiation of treatment. 16S and ITS rRNA sequence analysis were used to assess alterations in species abundance and richness of the colon. After sequencing, statistical analysis, specifically a paired t-test, was performed to assess if any significant differences in any microbial species were observed before and after immunotherapy treatment. Although different proportions of microorganisms existed at baseline prior to treatment for each patient, a significant reduction in the Megasphaera elsdenii population was observed (p=.0488; n=4), when comparing before and after treatment. Our findings differ from that of Huang et. al (2022), who has recently posited that a positive association exists between Megasphaera elsdenii and the survival of patients with pancreatic ductal adenocarcinomas. Our conclusions suggest that different cancers may elicit differential effects on Megasphaera elsdenii in the gut microbiome. ImportanceNivolumab is a relatively new form of cancer therapy called immunotherapy, which enables the body to use its own immune system to effectively fight cancer. Due to advances in microbial sequencing in 16S rRNA, this project explores differences in the abundance of microbial communities before and three months of treatment in patients who have advanced on chemotherapy. Our findings suggest that reduction of Megasphaera elsdenii, a metabolically active bacterium, is associated with positive outcomes, which differs from findings from other literature. Our project advocates for a more robust profiling of the microbiome during lung cancer treatment, and immunotherapy, in particular, to establish a more substantive profile of the changing gut in the midst of treatment.

cancer biology↗

bioRxiv2021

Diet High in Soybean Oil Increases Susceptibility to Colitis in Mice

The current American diet is high in soybean oil (SO), which consists of unsaturated fatty acids, most notably linoleic acid (LA, C18:2 omega-6). While LA is an essential fatty acid that must be obtained from the diet, high LA consumption has been linked to the development of inflammatory bowel disease (IBD) in humans. Here, we show that a high fat diet (HFD) based on soybean oil increases susceptibility to colitis in wild-type and IL10 knockout mice. It causes immune dysfunction, decreases colon and crypt length and increases intestinal epithelial barrier permeability; these effects were not observed in low LA HFDs. The SO diet also disrupts the balance of isoforms encoded by the IBD susceptibility gene Hepatocyte Nuclear Factor 4 (HNF4). Both the SO diet and an LA gavage cause gut dysbiosis: the SO diet increases the abundance of an adherent, invasive Escherichia coli (AIEC), which can use LA as a carbon source, and the LA gavage decreases the beneficial bacteria Lactobacillus murinus. Metabolomic analysis of both host-associated and cultured bacteria shows that SO increases levels of LA and oxylipins while decreasing eicosapentaenoic acid (EPA, C20:5 omega-3) and endocannabinoids. Our results suggest that excess LA, obtained from a diet high in soybean oil, increases susceptibility to colitis by alterations in intestinal HNF4, gut microbiota and bioactive metabolites.

physiology↗

bioRxiv2019

Herpes Simplex Virus Infection, Acyclovir and IVIG Treatment All Independently Cause Gut Dysbiosis.

Herpes simplex virus 1 (HSV) is a ubiquitous human virus resident in a majority of the global population as a latent infection. Acyclovir (ACV), is the standard of care drug used to treat primary and recurrent infections, supplemented in some patients with intravenous immunoglobulin (IVIG) treatment to suppress deleterious inflammatory responses. We found that HSV, ACV and IVIG can all independently disrupt the gut bacterial community in a sex biased manner when given to uninfected mice. Treatment of HSV infected mice with ACV or IVIG alone or together revealed complex interactions between these drugs and infection that caused pronounced sex biased dysbiosis. ACV reduced Bacteroidetes levels in male but not female mice, while levels of the Anti-inflammatory Clostridia (AIC) were reduced in female but not male mice, which is significant as these taxa are associated with protection against the development of GVHD in hematopoietic stem cell transplant (HSCT) patients. Gut barrier dysfunction is associated with GVHD in HSCT patients and ACV also decreased Akkermansia muciniphila, which is important for maintaining gut barrier functionality. Cumulatively, our data suggest that long-term prophylactic ACV treatment of HSCT patients may contribute to GVHD and potentially impact immune reconstitution. These data have important implications for other clinical settings, including HSV eye disease and genital infections, where ACV is given long-term. Author SummaryPrimary and reactivated HSV and VZV infections are treated with Acyclovir (ACV), an antiviral drug that blocks viral DNA synthesis. In some patients IVIG is used as adjunctive therapy to block deleterious inflammation. Long term preventative treatment of patients who receive stem transplants for various blood cancers has been successful in preventing life threatening reactivated HSV and VZV infections, but GVHD remains a major factor limiting transplant success. Studies reported here reveal that HSV infection, ACV and IVIG given alone can all disrupt the gut microbiota and that complex interactions between these drugs and infection results in even more pronounced sex biased changes in the gut bacteria community structure. Importantly, ACV treatment decreased the levels of specific bacterial taxa, including the anti-inflammatory Clostriodia and Bacteroidetes that have been shown to protect against development of GVHD in stem cell transplant patients. These data suggest that long term preventative treatment of patients with ACV may contribute to GVHD in transplant patients and have negative consequences in other HSV induced diseases treated long term with ACV. The health effects of long term ACV and IVIG treatments warrant further clinical studies.

microbiology↗

bioRxiv2019

The Autoimmune Susceptibility Gene, PTPN2, Restricts Expansion of a Novel Mouse Adherent-Invasive E. coli

Inflammatory bowel diseases (IBD) involve genetic and environmental factors that play major roles in disease pathogenesis. Loss-of-function single-nucleotide polymorphisms (SNPs) in the protein tyrosine phosphatase non-receptor type 2 (PTPN2) gene increase the risk of IBD and are associated with altered microbiome population dynamics in IBD. Moreover, expansion of intestinal pathobionts, such as adherent-invasive E. coli (AIEC), is strongly implicated in the pathogenesis of IBD as AIEC increases pro-inflammatory cytokine production and alters tight junction protein regulation suggesting a potential mechanism of pathogen-induced barrier dysfunction and inflammation. The aim of this study was to identify if PTPN2 deficiency disturbs the composition of the intestinal microbiome to promote expansion of specific bacteria with pathogenic properties. In mice constitutively lacking Ptpn2 we identified increased abundance of a novel adherent-invasive E. coli (AIEC) that showed similar adherence and invasion of intestinal epithelial cells, but greater survival in macrophages to the IBD associated AIEC, LF82. Furthermore, we confirmed this novel mouse AIEC (mAIEC) caused disease when administered to germ-free and mice lacking segmented-filamentous bacteria (SFB). Moreover, mAIEC infection increased severity of and prevented recovery from dextran-sodium sulfate (DSS)-induced colitis. mAIEC genome sequence analysis showed >90% similarity to LF82. Interestingly, mAIEC contained distinct attachment genes not found in LF82 thereby also demonstrating the novelty of this AIEC. We show here for the first time that an IBD susceptibility gene, PTPN2, plays a key role in modulating the gut microbiome to protect against a novel pathobiont. This study generates new insights into gene-environment-microbiome interactions in IBD.

microbiology↗