Transcriptional Behavior of Regulatory T Cells Predicts IBD Patient Responses to Vedolizumab Therapy

BACKGROUND

Inflammatory bowel disease (IBD) involves chronic T cell-mediated inflammatory responses. Vedolizumab (VDZ), a monoclonal antibody against α4β7 integrin, inhibits lymphocyte extravasation into intestinal mucosae and is effective in ulcerative colitis (UC) and Crohn's disease (CD).

AIM

We sought to identify immune cell phenotypic and gene expression signatures that related to response to VDZ.

METHODS

Peripheral blood (PBMC) and lamina propria mononuclear cells (LPMCs) were analyzed by flow cytometry and Cytofkit. Sorted CD4 + memory (Tmem) or regulatory T (Treg) cells from PBMC and LPMC were analyzed by RNA sequencing (RNA-seq). Clinical response (≥2-point drop in partial Mayo scores [UC] or Harvey-Bradshaw index [CD]) was assessed 14 to 22 weeks after VDZ initiation. Machine-learning models were used to infer combinatorial traits that predicted response to VDZ.

RESULTS

Seventy-one patients were enrolled: 37 received VDZ and 21 patients remained on VDZ >2 years. Fourteen of 37 patients (38%; 8 UC, 6 CD) responded to VDZ. Immune cell phenotypes and CD4 + Tmem and Treg transcriptional behaviors were most divergent between the ileum and colon, irrespective of IBD subtype or inflammation status. Vedolizumab treatment had the greatest impact on Treg metabolic pathways, and response was associated with increased expression of genes involved in oxidative phosphorylation. The strongest clinical predictor of VDZ efficacy was concurrent use of thiopurines. Mucosal tissues offered the greatest number of response-predictive biomarkers, whereas PBMC Treg-expressed genes were the best predictors in combinatorial models of response.

CONCLUSIONS

Mucosal and peripheral blood immune cell phenotypes and transcriptional profiles can inform VDZ efficacy and inform new opportunities for combination therapies.

Combining Pentoxifylline With Vedolizumab for Crohn's Disease: Results of a Randomised, Placebo-controlled Pilot Study

BACKGROUND AND AIMS

The efficacy of current biologics may be limited by targeting only one pathway. Pentoxifylline [PTX] interferes with tumour necrosis factor [TNF] gene expression. We performed a randomised, placebo-controlled pilot study to determine if PTX plus vedolizumab [VDZ] in patients with Crohn's disease [CD] is safe and improves response compared with VDZ monotherapy.

METHODS

Thirty adult patients with active CD were randomised to VDZ/PTX or VDZ/placebo and followed for 24 weeks. Endoscopic activity and inflammatory cytokines were measured at baseline and Week 24. Descriptive statistics were used to determine estimates of effect.

RESULTS

Demographics were similar but baseline disease activity was higher in the VDZ/PTX group. There was no difference in clinical remission at Week 14 (60.0% vs 66.67%, odds ratio [OR] 0.76, 95% confidence interval [CI] 0.16, 3.51) or steroid-free clinical remission at Week 24 in patients receiving VDZ/PTX. Improved clinical response was noted in the VDZ/PTX group at Weeks 6, 14, and 24 [Week 6: 20% vs 6.67%, Week 14: 26.67% vs 6.67%, Week 24: 40% vs 20%]. The rate of endoscopic remission was similar between the groups [40% vs 33.33%], with a greater mean decrease in Simple Endoscopic Score-CD [SES-CD] and C-reactive protein [CRP] with VDZ/PTX [SES-CD -3.17 vs -0.15, CRP -5.56 vs 0.46]. An increase in serum TNF-α concentration was observed with VDZ/placebo group; PTX mitigated this effect. No serious adverse events occurred.

CONCLUSIONS

VDZ/PTX did not provide benefit over VDZ monotherapy in clinical or endoscopic remission but appeared to improve clinical response and was safe. These data should inform a fully powered study.

Low-Fat, High-Fiber Diet Reduces Markers of Inflammation and Dysbiosis and Improves Quality of Life in Patients With Ulcerative Colitis

BACKGROUND & AIMS

A high-fat diet has been associated with an increased risk of ulcerative colitis (UC). We studied the effects of a low-fat, high-fiber diet (LFD) vs an improved standard American diet (iSAD, included higher quantities of fruits, vegetables, and fiber than a typical SAD). We collected data on quality of life, markers of inflammation, and fecal markers of intestinal dysbiosis in patients with UC.

METHODS

We analyzed data from a parallel-group, cross-over study of 17 patients with UC in remission or with mild disease (with a flare within the past 18 mo), from February 25, 2015, through September 11, 2018. Participants were assigned randomly to 2 groups and received a LFD (10% of calories from fat) or an iSAD (35%-40% of calories from fat) for the first 4-week period, followed by a 2-week washout period, and then switched to the other diet for 4 weeks. All diets were catered and delivered to patients' homes, and each participant served as her or his own control. Serum and stool samples were collected at baseline and week 4 of each diet and analyzed for markers of inflammation. We performed 16s ribosomal RNA sequencing and untargeted and targeted metabolomic analyses on stool samples. The primary outcome was quality of life, which was measured by the short inflammatory bowel disease (IBD) questionnaire at baseline and week 4 of the diets. Secondary outcomes included changes in the Short-Form 36 health survey, partial Mayo score, markers of inflammation, microbiome and metabolome analysis, and adherence to the diet.

RESULTS

Participants' baseline diets were unhealthier than either study diet. All patients remained in remission throughout the study period. Compared with baseline, the iSAD and LFD each increased quality of life, based on the short IBD questionnaire and Short-Form 36 health survey scores (baseline short IBD questionnaire score, 4.98; iSAD, 5.55; LFD, 5.77; baseline vs iSAD, P = .02; baseline vs LFD, P = .001). Serum amyloid A decreased significantly from 7.99 mg/L at baseline to 4.50 mg/L after LFD (P = .02), but did not decrease significantly compared with iSAD (7.20 mg/L; iSAD vs LFD, P = .07). The serum level of C-reactive protein decreased numerically from 3.23 mg/L at baseline to 2.51 mg/L after LFD (P = .07). The relative abundance of Actinobacteria in fecal samples decreased from 13.69% at baseline to 7.82% after LFD (P = .017), whereas the relative abundance of Bacteroidetes increased from 14.6% at baseline to 24.02% on LFD (P = .015). The relative abundance of Faecalibacterium prausnitzii was higher after 4 weeks on the LFD (7.20%) compared with iSAD (5.37%; P = .04). Fecal levels of acetate (an anti-inflammatory metabolite) increased from a relative abundance of 40.37 at baseline to 42.52 on the iSAD and 53.98 on the LFD (baseline vs LFD, P = .05; iSAD vs LFD, P = .09). The fecal level of tryptophan decreased from a relative abundance of 1.33 at baseline to 1.08 on the iSAD (P = .43), but increased to a relative abundance of 2.27 on the LFD (baseline vs LFD, P = .04; iSAD vs LFD, P = .08); fecal levels of lauric acid decreased after LFD (baseline, 203.4; iSAD, 381.4; LFD, 29.91; baseline vs LFD, P = .04; iSAD vs LFD, P = .02).

CONCLUSIONS

In a cross-over study of patients with UC in remission, we found that a catered LFD or iSAD were each well tolerated and increased quality of life. However, the LFD decreased markers of inflammation and reduced intestinal dysbiosis in fecal samples. Dietary interventions therefore might benefit patients with UC in remission. ClinicalTrials.gov no: NCT04147598.

Epithelial TLR4 Signaling Activates DUOX2 to Induce Microbiota-Driven Tumorigenesis

BACKGROUND & AIMS

Chronic colonic inflammation leads to dysplasia and cancer in patients with inflammatory bowel disease. We have described the critical role of innate immune signaling via Toll-like receptor 4 (TLR4) in the pathogenesis of dysplasia and cancer. In the current study, we interrogate the intersection of TLR4 signaling, epithelial redox activity, and the microbiota in colitis-associated neoplasia.

METHODS

Inflammatory bowel disease and colorectal cancer data sets were analyzed for expression of TLR4, dual oxidase 2 (DUOX2), and NADPH oxidase 1 (NOX1). Epithelial production of hydrogen peroxide (H₂O₂) was analyzed in murine colonic epithelial cells and colonoid cultures. Colorectal cancer models were carried out in villin-TLR4 mice, carrying a constitutively active form of TLR4, their littermates, and villin-TLR4 mice backcrossed to DUOXA-knockout mice. The role of the TLR4-shaped microbiota in tumor development was tested in wild-type germ-free mice.

RESULTS

Activation of epithelial TLR4 was associated with up-regulation of DUOX2 and NOX1 in inflammatory bowel disease and colorectal cancer. DUOX2 was exquisitely dependent on TLR4 signaling and mediated the production of epithelial H₂O₂. Epithelial H₂O₂ was significantly increased in villin-TLR4 mice; TLR4-dependent tumorigenesis required the presence of DUOX2 and a microbiota. Mucosa-associated microbiota transferred from villin-TLR4 mice to wild-type germ-free mice caused increased H₂O₂ production and tumorigenesis.

CONCLUSIONS

Increased TLR4 signaling in colitis drives expression of DUOX2 and epithelial production of H₂O₂. The local milieu imprints the mucosal microbiota and imbues it with pathogenic properties demonstrated by enhanced epithelial reactive oxygen species and increased development of colitis-associated tumors. The inter-relationship between epithelial reactive oxygen species and tumor-promoting microbiota requires a 2-pronged strategy to reduce the risk of dysplasia in colitis patients.

Expression of SARS-CoV-2 Entry Molecules ACE2 and TMPRSS2 in the Gut of Patients With IBD

BACKGROUND

Patients with inflammatory bowel disease (IBD) have intestinal inflammation and are treated with immune-modulating medications. In the face of the coronavirus disease-19 pandemic, we do not know whether patients with IBD will be more susceptible to infection or disease. We hypothesized that the viral entry molecules angiotensin I converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) are expressed in the intestine. We further hypothesized that their expression could be affected by inflammation or medication usage.

METHODS

We examined the expression of Ace2 and Tmprss2 by quantitative polymerase chain reacion in animal models of IBD. Publicly available data from organoids and mucosal biopsies from patients with IBD were examined for expression of ACE2 and TMPRSS2. We conducted RNA sequencing for CD11b-enriched cells and peripheral and lamina propria T-cells from well-annotated patient samples.

RESULTS

ACE2 and TMPRSS2 were abundantly expressed in the ileum and colon and had high expression in intestinal epithelial cells. In animal models, inflammation led to downregulation of epithelial Ace2. Expression of ACE2 and TMPRSS2 was not increased in samples from patients with compared with those of control patients. In CD11b-enriched cells but not T-cells, the level of expression of ACE2 and TMPRSS2 in the mucosa was comparable to other functional mucosal genes and was not affected by inflammation. Anti-tumor necrosis factor drugs, vedolizumab, ustekinumab, and steroids were linked to significantly lower expression of ACE2 in CD11b-enriched cells.

CONCLUSIONS

The viral entry molecules ACE2 and TMPRSS2 are expressed in the ileum and colon. Patients with IBD do not have higher expression during inflammation; medical therapy is associated with lower levels of ACE2. These data provide reassurance for patients with IBD.

Intestinal Epithelial Cells Respond to Chronic Inflammation and Dysbiosis by Synthesizing H2O2

The microbes in the gastrointestinal tract are separated from the host by a single layer of intestinal epithelial cells (IECs) that plays pivotal roles in maintaining homeostasis by absorbing nutrients and providing a physical and immunological barrier to potential pathogens. Preservation of homeostasis requires the crosstalk between the epithelium and the microbial environment. One epithelial-driven innate immune mechanism that participates in host-microbe communication involves the release of reactive oxygen species (ROS), such as hydrogen peroxide (H₂O₂), toward the lumen. Phagocytes produce high amounts of ROS which is critical for microbicidal functions; the functional contribution of epithelial ROS, however, has been hindered by the lack of methodologies to reliably quantify extracellular release of ROS. Here, we used a modified Amplex Red assay to investigate the inflammatory and microbial regulation of IEC-generated H₂O₂ and the potential role of Duox2, a NADPH oxidase that is an important source of H₂O₂. We found that colonoids respond to interferon-γ and flagellin by enhancing production of H₂O₂ in a Duox2-mediated fashion. To extend these findings, we analyzed ex vivo production of H₂O₂ by IECs after acute and chronic inflammation, as well as after exposure to dysbiotic microbiota. While acute inflammation did not induce a significant increase in epithelial-driven H₂O₂, chronic inflammation caused IECs to release higher levels of H₂O₂. Furthermore, colonization of germ-free mice with dysbiotic microbiota from mice or patients with IBD resulted in increased H₂O₂ production compared with healthy controls. Collectively, these data suggest that IECs are capable of H₂O₂ production during chronic inflammation and dysbiotic states. Our results provide insight into luminal production of H₂O₂ by IECs as a read-out of innate defense by the mucosa.

Microbial Signatures and Innate Immune Gene Expression in Lamina Propria Phagocytes of Inflammatory Bowel Disease Patients

BACKGROUND & AIMS

The interaction between intestinal microbiota and the immune system plays a vital role in inflammatory bowel disease (IBD). Although numerous deep-sequencing studies have suggested dysbiosis in IBD, identifying specific bacteria from the stool or mucosa that are responsible for disease susceptibility or severity has remained a challenge. Lamina propria phagocytes ideally are localized to interact with bacteria that are in close proximity to, or have invaded, the tissue. Thus, we examined the microbial populations associated with the lamina propria phagocytes in 20 Crohn's disease and 12 ulcerative colitis patients. Specifically, we aimed to address whether the phagocyte-associated microbiota differed from the mucosa-associated microbiota and whether this varied based on IBD type or the state of inflammation.

METHODS

16S ribosomal RNA gene sequencing and innate immune gene expression profiling was done on CD11b+ lamina propria phagocytes isolated from the biopsies obtained from IBD patients.

RESULTS

Phagocyte-associated microbiota was enriched in bacterial species belonging to phylum Proteobacteria, whereas species belonging to phylum Bacteroidetes were enriched in the mucosal microbiota of IBD patients. Disease type was the most influential factor in driving differences in the microbiota of both the mucosa and the lamina propria phagocytes, irrespective of inflammation state o`r anatomic location. Crohn's disease and ulcerative colitis specimens showed similar patterns of increased inflammatory gene expression in phagocytes isolated from inflamed areas compared with those isolated from uninflamed regions.

CONCLUSIONS

This pilot study shows the feasibility of using lamina propria phagocytes to characterize the microbiota in IBD patients. The approach used in this study can narrow the spectrum of potentially dysbiotic bacterial populations and clinically relevant gene expression signatures in IBD patients.

Conservation of pathogenic TCR homology across class II restrictions in anti-ribonucleoprotein autoimmunity: extended efficacy of T cell vaccine therapy

T cells have been shown to mediate aspects of anti-ribonucleoprotein (RNP) autoimmunity, and are a potential target of therapy in lupus and related diseases. In this study, we assessed the relevance of a conserved class of anti-RNP T cells to autoimmune disease expression and therapy. Our data show that anti-RNP T cell selection induced a limited set of homologous CDR3 motifs at high frequency. Homologous CDR3 motifs have been reported in other autoimmune diseases. Vaccination with irradiated anti-RNP (but not anti-tetanus toxoid) CD4(+) cells induced remission of anti-RNP-associated nephritis in ≥ 80% of treated mice, even with donor/recipient MHC class II mismatch, and in both induced and spontaneous autoimmunity. Vaccine responder sera inhibited anti-70k T cell proliferation and bound hybridomas expressing the conserved CDR3 motifs. Our data indicate that a limited set of TCR CDR3 motifs may be important for the pathogenesis of anti-RNP lupus and other autoimmune diseases. The ability to target a consistent set of pathogenic T cells between individuals and across class II restrictions may allow for the more practical development of a standardized anti-RNP T cell vaccine preparation useful for multiple patients.

Clinical and immunologic manifestations of mixed connective tissue disease in a Miami population compared to a Midwestern US Caucasian population

OBJECTIVE

A cross-sectional study of mixed connective tissue disease (MCTD) was performed to determine if there were identifiable differences in the clinical expression of MCTD associated with race or ethnicity.

METHODS

Miami, Florida, and Midwestern US (Missouri) Caucasian MCTD cohorts were studied. Clinical and laboratory features of the 2 MCTD cohorts were compared. A concurrently collected cohort of Sm-positive patients with systemic lupus erythematosus (SLE) was studied as a control. Disease activity and severity and functional status were measured. CD4+CD25(high)-expressing T-regulatory cells were enumerated and serum soluble L selectin was measured as biomarkers of disease activity.

RESULTS

The Miami and Missouri Caucasian MCTD groups, while differing from the SLE group, were largely similar; however, gastroesophageal reflux, sclerodactyly, and malar rash were significantly more frequent in the Missouri MCTD group and alopecia was more frequent in the Miami MCTD group. Significant clinical and laboratory differences were found between the Miami MCTD and Miami SLE groups despite similar disease duration, activity, severity and functional status. Raynaud's phenomenon (RP), hand swelling, synovitis, myositis, and sclerodactyly were all significantly more common in RNP-positive MCTD versus Sm-positive SLE subjects. CONCLUSION Ethnic differences were observed in the frequency of end-organ involvement in the Miami MCTD versus the Missouri Caucasian MCTD groups. Clinical and laboratory features of all MCTD groups were clearly different from the SLE group, despite similar disease activity, disease severity, and functional status. Disease activity measures appeared to behave similarly as valid measures of disease activity in SLE and MCTD.

Differential effects of continuous and intermittent 17beta-estradiol replacement and tamoxifen therapy on the prevention of glomerulosclerosis: modulation of the mesangial cell phenotype in vivo

Female ROP Os/+ mice are partially protected by endogenous estrogens against progressive glomerulosclerosis (GS) during their reproductive period; however, ovariectomy accelerates GS progression. We examined the effects of continuous and intermittent 17beta-estradiol (E(2)) replacement and tamoxifen therapy on the development of GS in ovariectomized (Ovx) ROP Os/+ mice. Continuous E(2) replacement (CE(2)) throughout 9 months prevented microalbuminuria and excess extracellular matrix accumulation in Ovx ROP Os/+, not only compared to placebo-treated Ovx mice but also in comparison to intact female ROP Os/+. Tamoxifen had a similar effect, but of lesser magnitude. Intermittent 3-month on-off-on E(2) did not reduce the kidney changes. Mesangial cells (MCs) from CE(2) mice maintained their estrogen responsiveness. E(2) in vitro prevented transforming growth factor-beta1 stimulation of a Smad-responsive reporter construct and increased MMP-2 expression and activity in MCs isolated from CE(2) mice. MCs from mice on either placebo or intermittent E(2) treatment did not respond to added E(2), consistent with a stable alteration of their estrogen responsiveness. Tamoxifen protection against GS was less pronounced in ROP Os/+ mice. Thus, prolonged estrogen deficiency promotes GS and renders MCs insensitive to subsequent estrogen treatment. This underscores the importance of continuous estrogen exposure for maintaining glomerular function and structure in females susceptible to progressive GS.