TL1A: A New Potential Target in the Treatment of Inflammatory Bowel Disease

Anti-TL1A monoclonal antibody modulates the dysregulation of Th1/Th17 cells and attenuates granuloma formation in sarcoidosis by inhibiting the PI3K/AKT signaling pathway

Sarcoidosis is a systemic granulomatous disease characterized by non-caseating epithelioid cell granulomas. One of its immunological hallmarks is the differentiation of CD4 + naïve T cells into Th1/Th17 cells, accompanied by the release of numerous pro-inflammatory cytokines. The TL1A/DR3 signaling pathway plays a crucial role in activating effector lymphocytes, thereby triggering pro-inflammatory responses. The primary aim of this investigation was to scrutinize the impact of anti-TL1A monoclonal antibody on the dysregulation of Th1/Th17 cells and granuloma formation in sarcoidosis. Initially, the abnormal activation of the TL1A/DR3 signaling pathway in pulmonary tissues of sarcoidosis patients was confirmed using qPCR and immunohistochemistry techniques. Subsequently, employing a murine model of sarcoidosis, the inhibitory effects of anti-TL1A monoclonal antibody on the TL1A/DR3 signaling pathway in sarcoidosis were investigated through qPCR, immunohistochemistry, and Western blot experiments. The influence of anti-TL1A monoclonal antibody on granulomas was assessed through HE staining, while their effects on sarcoidosis Th1/Th17 cells and associated cytokine mRNA levels were evaluated using flow cytometry and qPCR, respectively. Immunofluorescence and Western blot experiments corroborated the inhibitory effects of anti-TL1A monoclonal antibody on the aberrant activation of the PI3K/AKT signaling pathway in sarcoidosis. The findings of this study indicate that the TL1A/DR3 signaling pathway is excessively activated in sarcoidosis. Anti-TL1A monoclonal antibody effectively inhibit this abnormal activation in sarcoidosis, thereby alleviating the dysregulation of Th1/Th17 cells and reducing the formation of pulmonary granulomas. This effect may be associated with the inhibition of the downstream PI3K/AKT signaling pathway. Anti-TL1A monoclonal antibody hold promise as a potential novel therapeutic intervention for sarcoidosis.

Preventing fibrosis in IBD: update on immune pathways and clinical strategies

INTRODUCTION

Intestinal fibrosis is a common and serious complication of inflammatory bowel diseases (IBD) driving stricture formation in Crohn's disease patients and leading to submucosal damage in ulcerative colitis. Recent studies provided novel insights into the role of immune and nonimmune components in the pathogenesis of intestinal fibrosis. Those new findings may accelerate the development of anti-fibrotic treatment in IBD patients.

AREAS COVERED

This review is designed to cover the recent progress in mechanistic research and therapeutic developments on intestinal fibrosis in IBD patients, including new cell clusters, cytokines, proteins, microbiota, creeping fat, and anti-fibrotic therapies.

EXPERT OPINION

Due to the previously existing major obstacle of missing consensus on stricture definitions and the absence of clinical trial endpoints, testing of drugs with an anti-fibrotic mechanism is just starting in stricturing Crohn's disease (CD). A biomarker to stratify CD patients at diagnosis without any complications into at-risk populations for future strictures would be highly desirable. Further investigations are needed to identify novel mechanisms of fibrogenesis in the intestine that are targetable and ideally gut specific.

The TNFSF12/TWEAK Modulates Colonic Inflammatory Fibroblast Differentiation and Promotes Fibroblast-Monocyte Interactions

Fibroblasts acquire a proinflammatory phenotype in inflammatory bowel disease, but the factors driving this process and how fibroblasts contribute to mucosal immune responses are incompletely understood. TNF superfamily member 12 (TNFSF12, or TNF-like weak inducer of apoptosis [TWEAK]) has gained interest as a mediator of chronic inflammation. In this study, we explore its role as a driver of inflammatory responses in fibroblasts and its contribution to fibroblast-monocyte interaction using human primary colonic fibroblasts, THP-1 and primary monocytes. Recombinant human TWEAK induced the expression of cytokines, chemokines, and immune receptors in primary colonic fibroblasts. The TWEAK upregulated transcriptome shared 29% homology with a previously published transcriptional profile of inflammatory fibroblasts from ulcerative colitis. TWEAK elevated surface expression of activated fibroblast markers and adhesion molecules (podoplanin [PDPN], ICAM-1, and VCAM-1) and secretion of IL-6, CCL2, and CXCL10. In coculture, fibroblasts induced monocyte adhesion and secretion of CXCL1 and IL-8, and they promoted a CD14high/ICAM-1high phenotype in THP-1 cells, which was enhanced when fibroblasts were prestimulated with TWEAK. Primary monocytes in coculture with TWEAK-treated fibroblasts had altered surface expression of CD16 and triggering receptor expressed on myeloid cells-1 (TREM-1) as well as increased CXCL1 and CXCL10 secretion. Conversely, inhibition of the noncanonical NF-κB pathway on colonic fibroblasts with a NF-κB-inducing kinase small molecule inhibitor impaired their ability to induce a CD14high phenotype on monocytes. Our results indicate that TWEAK promotes an inflammatory fibroblast-monocyte crosstalk that may be amenable for therapeutic intervention.

Illness Perceptions as a Predictor of Symptom Cluster Trajectories in Patients With Inflammatory Bowel Disease: A Latent Growth Mixture Model

The aims of this study were to (a) identify the trajectory of symptom clusters in patients with inflammatory bowel disease up to 28 weeks after initiation of infliximab therapy and (b) examine the illness perceptions associated with symptom cluster trajectories. This was a prospective study where participants completed the symptom cluster scale at baseline, 14 weeks, and 28 weeks. A latent growth mixture modeling was used to identify trajectories of symptom clusters that were predicted, using baseline covariates (Brief Illness Perception Questionnaire). A total of 206 patients were included and identified as three latent classes: moderate symptom cluster-stable decline group (C1), high symptom cluster-rapid decline group (C2), and stable symptom cluster-stable trend group (C3). C1 was predicted by cognitive illness perceptions (odds ratio [95% confidence interval]: 1.134 [1.071, 1.200], p < .001). C2 was also predicted by cognitive and emotional illness perceptions (odds ratio [95% confidence interval]: 1.169 [1.095, 1.248], p < .001; odds ratio [95% confidence interval]: 1.174 [1.038, 1.328], p = .011). Patients with inflammatory bowel disease, initiating infliximab therapy, had different symptom cluster trajectories. Illness perceptions were associated with symptom cluster classes, which underline the complexity of symptoms. Paying attention to these factors and providing necessary knowledge and psychological supporting care after infliximab therapy would effectively improve patients' symptom burden.

TL1A promotes metastasis and EMT process of colorectal cancer

Background

Metastasis is the major problem of colorectal cancer (CRC) and is correlated with the high mortality. Tumor necrosis factor-like cytokine 1A (TL1A) is a novel regulatory factor for inflammatory diseases. This work aimed to investigate the role of TL1A in CRC metastasis.

Method

AOM/DSS-induced mouse model, xenograft tumor model and metastasis murine model were established to mimic the colitis-associated CRC and investigate CRC growth and metastasis in vivo. Colon tissues were assessed by hematoxylin/eosin (HE) staining and immunohistochemistry (IHC). CRC cell metastasis in vivo was observed using in vivo imaging system (IVIS). Cell viability and proliferation were examined using cell counting kit 8 (CCK-8) and EdU experiments. The expression of tumor growth factor β (TGFβ) and metastatic biomarkers were detected using western blotting experiment. The in vitro cell metastasis was measured by Transwell.

Results

Knockdown of TL1A notably suppressed the generation of colonic tumors in azoxymethane/dextran sodium sulfate (AOM/DSS) model, suppressed in vivo CRC cell growth, as well as lung and liver metastasis. The inflammation response and inflammatory cell infiltration in tumor sites were decreased by TL1A depletion. The in vitro CRC cell growth and metastasis was also suppressed by shTL1A, along with altered expression of epithelial mesenchymal transition (EMT) biomarkers. TL1A depletion suppressed the level of the TGF-β1 receptor (TβRI) and phosphorylation of Smad3 in CRC cells. Stimulation with TGF-β recovered the CRC cell migration and invasion that suppressed by shTL1A.

Conclusion

Our work implicated TL1A as a promoter of CRC generation and metastasis and defines TGF-β/Smad3 signaling as mediator of TL1A-regualated CRC cell metastasis.

Eicosatetraynoic Acid Regulates Pro-Fibrotic Pathways in an Induced Pluripotent Stem Cell Derived Macrophage:Human Intestinal Organoid Model of Crohn's Disease

Background and Aims

We previously identified small molecules predicted to reverse an ileal gene signature for future Crohn's Disease (CD) strictures. Here we used a new human intestinal organoid (HIO) model system containing macrophages to test a lead candidate, eicosatetraynoic acid (ETYA).

Methods

Induced pluripotent stem cell lines (iPSC) were derived from CD patients and differentiated into macrophages and HIOs. Macrophages and macrophage:HIO co-cultures were exposed to lipopolysaccharide (LPS) with and without ETYA pre-treatment. Cytospin and flow cytometry characterized macrophage morphology and activation markers, and RNA sequencing defined the global pattern of macrophage gene expression. TaqMan Low Density Array, Luminex multiplex assay, immunohistologic staining, and sirius red polarized light microscopy were performed to measure macrophage cytokine production and HIO pro-fibrotic gene expression and collagen content.

Results

iPSC-derived macrophages exhibited morphology similar to primary macrophages and expressed inflammatory macrophage cell surface markers including CD64 and CD68. LPS-stimulated macrophages expressed a global pattern of gene expression enriched in CD ileal inflammatory macrophages and matrisome secreted products, and produced cytokines and chemokines including CCL2, IL1B, and OSM implicated in refractory disease. ETYA suppressed CD64 abundance and pro-fibrotic gene expression pathways in LPS stimulated macrophages. Co-culture of LPS-primed macrophages with HIO led to up-regulation of fibroblast activation genes including ACTA2 and COL1A1 , and an increase in HIO collagen content. ETYA pre-treatment prevented pro-fibrotic effects of LPS-primed macrophages.

Conclusions

ETYA inhibits pro-fibrotic effects of LPS-primed macrophages upon co-cultured HIO. This model may be used in future untargeted screens for small molecules to treat refractory CD.

Speos: an ensemble graph representation learning framework to predict core gene candidates for complex diseases

Understanding phenotype-to-genotype relationships is a grand challenge of 21st century biology with translational implications. The recently proposed "omnigenic" model postulates that effects of genetic variation on traits are mediated by core-genes and -proteins whose activities mechanistically influence the phenotype, whereas peripheral genes encode a regulatory network that indirectly affects phenotypes via core gene products. Here, we develop a positive-unlabeled graph representation-learning ensemble-approach based on a nested cross-validation to predict core-like genes for diverse diseases using Mendelian disorder genes for training. Employing mouse knockout phenotypes for external validations, we demonstrate that core-like genes display several key properties of core genes: Mouse knockouts of genes corresponding to our most confident predictions give rise to relevant mouse phenotypes at rates on par with the Mendelian disorder genes, and all candidates exhibit core gene properties like transcriptional deregulation in disease and loss-of-function intolerance. Moreover, as predicted for core genes, our candidates are enriched for drug targets and druggable proteins. In contrast to Mendelian disorder genes the new core-like genes are enriched for druggable yet untargeted gene products, which are therefore attractive targets for drug development. Interpretation of the underlying deep learning model suggests plausible explanations for our core gene predictions in form of molecular mechanisms and physical interactions. Our results demonstrate the potential of graph representation learning for the interpretation of biological complexity and pave the way for studying core gene properties and future drug development.

Inflammatory Bowel Disease: Emerging Therapies and Future Treatment Strategies

Inflammatory bowel disease (IBD) is a term used to represent a group of chronic, relapsing inflammatory disorders of the gastrointestinal tract. Crohn's disease (CD) and ulcerative colitis (UC) are the two major clinical forms. The global incidence and prevalence of IBD have increased over the last 2-4 decades. Despite the specific etiopathogenesis of IBD still being unknown, it is widely recognized that immunological, genetic, and environmental factors are implicated. A greater understanding of the multiple signaling pathways involved has led to the development of biologic therapies in the last two decades. Although these treatments have dramatically transformed the course of IBD, there is not a definitive cure and available therapies may cause adverse events (AEs), limiting their use, or have an inadequate effect in some patients. In this context, emerging therapies addressing new specific pathogenetic mechanisms have shown promising efficacy and safety data in early clinical trials. The purpose of this review is to highlight the available clinical trial data for these new drugs, such as more preferential JAK inhibitors, anti-IL-23 antibodies, sphingosine-1-phosphate receptor modulators, anti-integrin therapies, and other small molecules that are currently under research. We will emphasize the potential significance of these agents in shaping future treatment options.

Astragaloside IV regulates TL1A and NF-κB signal pathway to affect inflammation in necrotizing enterocolitis

AIM

This study aims to explore the possible effect of Astragaloside IV (AS-IV) on necrotizing enterocolitis (NEC) neonatal rat models and verify the possible implication of TNF-like ligand 1 A (TL1A) and NF-κB signal pathway.

METHODS

NEC neonatal rat models were established through formula feeding, cold/asphyxia stress and Lipopolysaccharide (LPS) gavage method. The appearance, activity and skin as well as the pathological status of rats subjected to NEC modeling were assessed. The intestinal tissues were observed after H&E staining. The expression of oxidative stress biomarkers (SOD, MDA and GSH-Px) and inflammatory cytokines (TNF-α, IL-1β and IL-6) were detected by ELISA and qRT-PCR. Western blotting and immunohistochemistry were applied to detect expressions of TL1A and NF-κB signal pathway-related proteins. Cell apoptosis was assessed by TUNEL.

RESULTS

NEC neonatal rat models were established successfully, in which TL1A was highly expressed and NF-κB signal pathway was activated, while TL1A and NF-κB signal pathway can be suppressed by AS-IV treatment in NEC rats. Meanwhile, inflammatory response in intestinal tissues was increased in NEC rat models and AS-IV can attenuate inflammatory response in NEC rats through inhibiting TL1A and NF-κb signal pathway.

CONCLUSION

AS-IV can inhibit TL1A expression and NF-κb signal pathway to attenuate the inflammatory response in NEC neonatal rat models.

New and Emerging Treatments for Inflammatory Bowel Disease

BACKGROUND

The specific etiopathogenesis of inflammatory bowel disease (IBD) is still unknown. Although the conventional anti-inflammatory or immunomodulatory drugs relatively nonspecific to pathogenesis have been quite useful in many cases, elucidating the pathogenesis has gradually facilitated developments of disease-specific therapies for refractory cases in the last 2 decades.

SUMMARY

With a greater understanding of the multiple overactive signaling pathways of the gut mucosal immune response and enhanced leukocyte trafficking, several biological agents or small molecule drugs following the first novel biologic, anti-tumor necrosis factor α (anti-TNFα), have been developed against several modes of action including adhesion molecules, sphingosine-1-phospate receptors, cytokines (IL-12/23, TL1A, and IL-36), Janus kinase (JAK), and phosphodiesterase. Although preceding biological agents have dramatically changed the IBD treatment strategy, many patients still require alternative therapies due to failure or side effects. Newer treatments are now expected to be provided for better efficacy with an improved adverse event profile. In addition, translational studies have highlighted the new therapeutic concepts' potential, including modulation of host-microbiome interactions, stem therapy for perianal fistula, regulation of fibrosis, regulation of the gut-brain axis, and control of previously less targeted immune cells (B cells and innate lymphoid cells). This paper comprehensively reviewed not only the latest already or shortly available therapies but also emerging promising treatments that will be hopefully established in the future for IBD.

KEY MESSAGES

Many kinds of new treatments are available, and promising treatments with new perspectives are expected to emerge for refractory IBD in the future.

Tackling Inflammatory Bowel Diseases: Targeting Proinflammatory Cytokines and Lymphocyte Homing

Inflammatory bowel diseases (IBDs) are characterized by chronic inflammatory disorders that are a result of an abnormal immune response mediated by a cytokine storm and immune cell infiltration. Proinflammatory cytokine therapeutic agents, represented by TNF inhibitors, have developed rapidly over recent years and are promising options for treating IBD. Antagonizing interleukins, interferons, and Janus kinases have demonstrated their respective advantages in clinical trials and are candidates for anti-TNF therapeutic failure. Furthermore, the blockade of lymphocyte homing contributes to the excessive immune response in colitis and ameliorates inflammation and tissue damage. Factors such as integrins, selectins, and chemokines jointly coordinate the accumulation of immune cells in inflammatory regions. This review assembles the major targets and agents currently targeting proinflammatory cytokines and lymphatic trafficking to facilitate subsequent drug development.