Experimental colitis in IL-10-deficient mice ameliorates in the absence of PTPN22

Real-world of Limosilactobacillus reuteri in mitigation of acute experimental colitis

Probiotics have been proposed as a potential strategy for managing ulcerative colitis (UC). However, the underlying mechanisms mediating microbiota-host crosstalk remain largely elusive. Here, we report that Limosilactobacillus reuteri (L. reuteri), as a probiotic, secretes cytoplasmic membrane vesicles (CMVs) that communicate with host cells, alter host physiology, and alleviate dextran sulfate sodium (DSS)-induced colitis. First, L. reuteri-CMVs selectively promoted the proliferation of the beneficial bacterium Akkermansia muciniphila (AKK) by upregulating the expression of glycosidases (beta-N-acetylhexosaminidase and alpha-N-acetylglucosaminidase) involved in glycan degradation and metabolic pathways and restored the disrupted gut microbiota balance. Second, L. reuteri-CMVs were taken up by intestinal epithelial cells (IECs), elevated the expression of ZO-1, E-cadherin (Cdh1), and Occludin (Ocln), decreased intestinal permeability, and exerted protective effects on epithelial tight junction functionality. RNA sequencing analysis demonstrated that L. reuteri-CMVs repaired intestinal barrier by activating the HIF-1 signaling pathway and upregulating HMOX1 expression. Third, L. reuteri-CMVs increased the population of double positive (DP) CD4+CD8+ T cells in the intestinal epithelial layer, suppressing gut inflammation and maintaining gut mucosal homeostasis. Finally, L. reuteri-CMVs exhibited satisfactory stability and safety in the gastrointestinal tract and specifically targeted the desired sites in colitis mice. Collectively, these findings shed light on how L. reuteri interact with the host in colitis, and provide new insights into potential strategies for alleviating colitis.

Dysregulation of T cell response in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD), comprised of Crohn's disease (CD) and ulcerative colitis (UC), are gut inflammatory diseases that were earlier prevalent in the Western Hemisphere but now are on the rise in the East, with India standing second highest in the incidence rate in the world. Inflammation in IBD is a cause of dysregulated immune response, wherein helper T (Th) cell subsets and their cytokines play a major role in the pathogenesis of IBD. In addition, gut microbiota, environmental factors such as dietary factors and host genetics influence the outcome and severity of IBD. Dysregulation between effector and regulatory T cells drives gut inflammation, as effector T cells like Th1, Th17 and Th9 subsets Th cell lineages were found to be increased in IBD patients. In this review, we attempted to discuss the role of different Th cell subsets together with other T cells like CD8+ T cells, NKT and γδT cells in the outcome of gut inflammation in IBD. We also highlighted the potential therapeutic candidates for IBD.

Role of Protein Tyrosine Phosphatases in Inflammatory Bowel Disease, Celiac Disease and Diabetes: Focus on the Intestinal Mucosa

Protein tyrosine phosphatases (PTPs) are a family of enzymes essential for numerous cellular processes, such as cell growth, inflammation, differentiation, immune-mediated responses and oncogenic transformation. The aim of this review is to review the literature concerning the role of several PTPs-PTPN22, PTPN2, PTPN6, PTPN11, PTPσ, DUSP2, DUSP6 and PTPRK-at the level of the intestinal mucosa in inflammatory bowel disease (IBD), celiac disease (CeD) and type 1 diabetes (T1D) in both in vitro and in vivo models. The results revealed shared features, at the level of the intestinal mucosa, between these diseases characterized by alterations of different biological processes, such as proliferation, autoimmunity, cell death, autophagy and inflammation. PTPs are now actively studied to develop new drugs. Also considering the availability of organoids as models to test new drugs in personalized ways, it is very likely that soon these proteins will be the targets of useful drugs.

[Old and New Biologics and Small Molecules in Inflammatory Bowel Disease: Anti-interleukins]

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic inflammatory disease of the gastrointestinal tract. The introduction of biologics, particularly anti-interleukin (IL) agents, has revolutionized IBD treatment. This review summarizes the role of ILs in IBD pathophysiology and describes the efficacy and positioning of anti-IL therapies. We discuss the functions of key ILs in IBD and their potential as therapeutic targets. The review then discusses anti-IL therapies, focusing primarily on ustekinumab (anti-IL-12/23), risankizumab (anti-IL-23), and mirikizumab (anti-IL-23). Clinical trial data demonstrate their efficacy in inducing and maintaining remission in Crohn's disease and ulcerative colitis. The safety profiles of these agents are generally favorable. However, long-term safety data for newer agents are still limited. The review also briefly discusses emerging therapies such as guselkumab and brazikumab. Network meta-analyses suggest that anti-IL therapies perform well compared to other biological agents. These agents may be considered first- or second-line therapies for many patients, especially those with comorbidities or safety concerns. Anti-IL therapies represent a significant advancement in IBD treatment, offering effective and relatively safe options for patients with moderate to severe disease.

Regulation of T Cell Signaling and Immune Responses by PTPN22

Protein tyrosine phosphatases (PTPs) play central roles in the regulation of cell signaling, organismal development, cellular differentiation and proliferation, and cancer. In the immune system, PTPs regulate the activation, differentiation and effector function of lymphocytes and myeloid cells whilst single-nucleotide polymorphisms (SNPs) in PTP-encoding genes have been identified as risk factors for the development of autoimmunity. In this review we describe the roles for PTP nonreceptor type 22 (PTPN22) in the regulation of T lymphocyte signaling and activation in autoimmunity, infection and cancer. We summarize recent progress in our understanding of the regulation of PTPN22 activity, the impact of autoimmune disease-associated PTPN22 SNPs on T cell responses and describe approaches to harness PTPN22 as a target to improve T cell-based immunotherapies in cancer.

Engaging natural antibody responses for the treatment of inflammatory bowel disease via phosphorylcholine-presenting nanofibres

Inflammatory bowel disease lacks a long-lasting and broadly effective therapy. Here, by taking advantage of the anti-infection and anti-inflammatory properties of natural antibodies against the small-molecule epitope phosphorylcholine (PC), we show in multiple mouse models of colitis that immunization of the animals with self-assembling supramolecular peptide nanofibres bearing PC epitopes induced sustained levels of anti-PC antibodies that were both protective and therapeutic. The strength and type of immune responses elicited by the nanofibres could be controlled through the relative valency of PC epitopes and exogenous T-cell epitopes on the nanofibres and via the addition of the adjuvant CpG. The nanomaterial-assisted induction of the production of therapeutic antibodies may represent a durable therapy for inflammatory bowel disease.

The role of JAK2/STAT3 pathway in non-cytotoxic concentrations of DON-induced aggravation of inflammatory response in IL-10 deficient RAW264.7 cells

Deoxynivalenol (DON) as a mycotoxin was commonly found in food and cereals which can affect immune function and inflammatory response. The majority of foods contain DON at levels below the official limit. This study aimed to evaluate the effects of non-cytotoxic concentration of DON on inflammation and its mechanisms using the IL-10 gene-silenced RAW264.7 cell model. The results showed that a non-cytotoxic concentration of DON at 25 ng/ml aggravated IL-10 knockdown-induced inflammation, which was manifested by increasing IL-1β and TNF-α mRNA expression, migration and phagocytosis, decreasing IL-10 mRNA expression, and enhancing JAK2/STAT3 phosphorylation. Adding JAK2 inhibitor AG490 attenuated the aggravating effect of DON on IL-10 knockdown-induced inflammation. In conclusion, a non-cytotoxic concentration of DON enhances the inflammatory response through the JAK2/STAT3 signaling pathway when inflammation occurs in the body. These results indicated that non-cytotoxic concentrations of DON could aggravate inflammation when inflammation was induced by IL-10 knockdown, which increases vigilance against DON contamination at low concentration especially when an animal's body has inflammation.

MicroRNA-143-3p ameliorates collagen-induced arthritis by polarizing naive CD4+ T cells into Treg cells

BACKGROUND

Rheumatoid arthritis (RA) is a persistent and systemic autoimmunity disease. The abnormal differentiation of Treg cells is important in pathogenesis. Despite previous studies showed that microRNAs (miRNAs, miR) are pivotal modulators of Treg cells, the effect of miRNAs on Treg cell differentiation and function is not clear. Our study wants to reveal the relationship of miR-143-3p with the differentiative ability and biofunction of Treg cells during the development of RA.

METHODS

The Expressing level of miR-143-3p and cell factor generation in peripheral blood (PB) of RA sufferers were identified by ELISA or RT-qPCR. The roles of miR-143-3p in Treg cell differentiation were studied via ShRNA/lentivirus transfection. Male DBA/1 J mice were separated into control, model, control mimics, and miR-143-3p mimics groups to analyze the anti-arthritis efficacy, the differentiative ability of Treg cells, and the expression level of miR-143-3p.

RESULTS

Our team discovered that the Expressing level of miR-143-3p was related to RA disease activities in a negative manner, and remarkably related to antiinflammation cell factor IL-10. In vitro, the expression of miR-143-3p in the CD4⁺ T cells upregulated the percentage of CD4⁺ CD25⁺ Fxop3⁺ cells (Tregs) and forkhead box protein 3 (Foxp3) mRNA expression. Evidently, miR-143-3p mimic intervention considerably upregulated the content of Treg cells in vivo, validly avoided CIA progression, and remarkably suppressed the inflammatory events of joints in mice.

CONCLUSION

Our findings indicated that miR-143-3p could ameliorate CIA through polarizing naive CD4⁺ T cells into Treg cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Sotetsuflavone ameliorates Crohn's disease-like colitis by inhibiting M1 macrophage-induced intestinal barrier damage via JNK and MAPK signalling

OBJECTIVES

Intestinal inflammation and intestinal barrier dysfunction are two important pathological changes in Crohn's disease (CD). Sotetsuflavone (SF) is a natural monomeric herbal compound with anti-inflammatory and cytoprotective effects that is mostly nontoxic. The effect of SF on CD-like spontaneous colitis was investigated in this study.

METHODS

Il-10^-/- mice were used as a CD model and were administered different doses of SF. Lipopolysaccharide (LPS) plus IFN-γ-induced macrophages (RAW264.7) and a coculture system (RAW264.7 and organoids) were used in vitro. The protective effects of SF against CD-like colitis and macrophage differentiation and the mechanisms were evaluated.

RESULTS

SF treatment markedly improved spontaneous colitis in the CD model, as shown by the following evidence: reductions in the DAI, macroscopic scores (3.63 ± 1.30), colonic tissue inflammatory scores (2 ± 0.76) and proinflammatory factor levels and the attenuation of colon shortening (8 ± 0.93 cm) and weight loss (1.75 ± 1.83 g). Decreased intestinal permeability and intestinal bacterial translocation rates provided evidence of the protective effect of SF on intestinal barrier function. We also found that SF suppressed M1 macrophage-induced inflammatory responses. In the coculture system of mouse colonic organoids and RAW264.7 cells, SF significantly ameliorated M1 macrophage-induced intestinal epithelial damage. In addition, SF inhibited JNK and MAPK (p38) signalling in both Il-10^-/- mice and LPS plus IFN-γ-induced macrophages (RAW264.7).

CONCLUSIONS

The protective effects of SF against CD-like colitis may be achieved partially by inhibiting M1 macrophage-induced intestinal barrier damage via JNK and p38 signalling. SF may have therapeutic potential for treating CD, especially considering its safety.

Evolving Experimental Platforms to Evaluate Ulcerative Colitis

Ulcerative colitis (UC) is a multifactorial disease defined by chronic intestinal inflammation with idiopathic origins. It has a predilection to affect the mucosal lining of the large intestines and rectum. Management of UC depends upon numerous factors that include disease pathogenesis and severity that are maintained via medical or surgical means. Chronic inflammation that is left untreated or managed poorly from a clinical stance can result in intestinal ulceration accompanied by resulting physiological dysfunction. End-stage UC is mediated by surgical intervention with the resection of diseased tissue. This can lead to numerous health-related quality of life issues but is considered a curative approach. Regimens to treat UC are ever evolving and find their basis within various platforms to evaluate and treat UC. Numerous modeling systems have been examined to delineate potential mechanisms of action. However, UC is a heterogenous disease spanning unknown genetic origins coupled with environmental factors that can influence disease outcomes and related treatment procedures. Unfortunately, there is no one-size-fits-all model to fully assess all facets of UC. Within the context of this review article, the utility of various approaches that have been employed to gain insight into different aspects of UC will be investigated.

Differentiation and homeostasis of effector Treg cells are regulated by inositol polyphosphates modulating Ca2+ influx

Activated Foxp3⁺ regulatory T (Treg) cells differentiate into effector Treg (eTreg) cells to maintain peripheral immune homeostasis and tolerance. T cell receptor (TCR)-mediated induction and regulation of store-operated Ca²⁺ entry (SOCE) is essential for eTreg cell differentiation and function. However, SOCE regulation in Treg cells remains unclear. Here, we show that inositol polyphosphate multikinase (IPMK), which generates inositol tetrakisphosphate and inositol pentakisphosphate, is a pivotal regulator of Treg cell differentiation downstream of TCR signaling. IPMK is highly expressed in TCR-stimulated Treg cells and promotes a TCR-induced Treg cell program. IPMK-deficient Treg cells display aberrant T cell activation and impaired differentiation into RORγt⁺ Treg cells and tissue-resident Treg cells. Mechanistically, IPMK controls the generation of higher-order inositol phosphates, thereby promoting Ca²⁺ mobilization and Treg cell effector functions. Our findings identify IPMK as a critical regulator of TCR-mediated Ca²⁺ influx and highlight the importance of IPMK in Treg cell-mediated immune homeostasis.

Regulatory role of short-chain fatty acids in inflammatory bowel disease

Inflammatory bowel disease (IBD) comprises a group of chronic inflammatory disorders of the gastrointestinal tract. Accumulating evidence shows that the development of IBD is always accompanied by the dysbiosis of the gut microbiota (GM), causing a decrease in prebiotic levels and an increase in harmful metabolite levels. This leads to persistent immune response and inflammation in the intestine, greatly impairing the physiological function of the gastrointestinal tract. Short-chain fatty acids (SCFAs) are produced by probiotic gut bacteria from a fiber-rich diet that cannot be digested directly. SCFAs with significant anti-inflammatory functions regulate immune function and prevent an excessive immune response, thereby delaying the clinical progression of IBD. In this review, we summarize the generation of SCFAs and their potential therapeutic effects on IBD. Furthermore, we suggest that SCFAs may modulate innate immune recognition and cytokine production to intervene in the progression of IBD. Additional randomized controlled trials and prospective cohort studies should also investigate the clinical impact of SCFA. Video Abstract.

Loss of PTPN22 Promotes Intestinal Inflammation by Compromising Granulocyte-mediated Antibacterial Defence

BACKGROUND AND AIMS

A single nucleotide polymorphism in protein tyrosine phosphatase non-receptor type 22 [PTPN22] has been associated with the onset of autoimmune disorders, but protects from Crohn's disease. PTPN22 deficiency in mice promotes intestinal inflammation by modulating lymphocyte function. However, the impact of myeloid PTPN22 in colitis development remains unclear. The aim of this study was to investigate the role of PTPN2 in the IL-10 and the T cell transfer colitis models.

METHODS

PTPN22-deficient mice were crossed with IL-10-/- and RAG2-/- mice. Naïve T cells were injected in RAG-/- mice to induce T-cell transfer colitis. Spontaneous colitis in IL-10-/- mice was monitored for up to 200 days.

RESULTS

Here, we demonstrate that PTPN22 in non-lymphoid immune cells is required to protect against T cell transfer-mediated and IL-10 knock-out colitis. Analysis of the intestinal immune landscape demonstrated a marked reduction of granulocyte influx into the inflamed colon in PTPN22-deficient mice. On a molecular level, granulocytes were not only reduced by numbers, but also revealed a defective function. In particular, granulocyte activation and granulocyte-mediated bacteria killing was impaired upon loss of PTPN22, resulting in elevated bacterial burden and translocation beyond the intestinal epithelial barrier in PTPN22-deficient mice. Consistently, antibiotic-induced depletion of bacteria reverted the increased colitis susceptibility in PTPN22-deficient mice, whereas granulocyte depletion induced acolitis phenotype in wild-type mice similar to that observed in PTPN22-deficient mice.

CONCLUSIONS

In conclusion, our data demonstrate that PTPN22 is essential for adequate granulocyte activation and antimicrobial defence to protect the inflamed intestine from bacterial invasion and exacerbated colitis.

Reduced Follicular Regulatory T Cells in Spleen and Pancreatic Lymph Nodes of Patients With Type 1 Diabetes

In the attempt to understand the origin of autoantibody (AAb) production in patients with and at risk for type 1 diabetes (T1D), multiple studies have analyzed and reported alterations in T follicular helper (Tfh) cells in presymptomatic AAb⁺ subjects and patients with T1D. Yet, whether the regulatory counterpart of Tfh cells, represented by T follicular regulatory (Tfr) cells, is similarly altered is still unclear. To address this question, we performed analyses in peripheral blood, spleen, and pancreatic lymph nodes (PLN) of organ donor subjects with T1D. Blood analyses were also performed in living AAb^- and AAb⁺ subjects. While negligible differences in the frequency and phenotype of blood Tfr cells were observed among T1D, AAb^-, and AAb⁺ adult subjects, the frequency of Tfr cells was significantly reduced in spleen and PLN of T1D as compared with nondiabetic control subjects. Furthermore, adoptive transfer of Tfr cells delayed disease development in a mouse model of T1D, a finding that could indicate that Tfr cells play an important role in peripheral tolerance and regulation of autoreactive Tfh cells. Together, our findings provide evidence of Tfr cell alterations within disease-relevant tissues in patients with T1D, suggesting a role for Tfr cells in defective humoral tolerance and disease pathogenesis.

The Potential Advantage of Targeting Both PD-L1/PD-L2/PD-1 and IL-10-IL-10R Pathways in Acute Myeloid Leukemia

Tumor cells promote the suppression of host anti-tumor type 1 T cell responses by various mechanisms, including the upregulation of surface inhibitory molecules such as programmed death ligand (PD-L)-1, and the production of immunosuppressive cytokines such as interleukin-10 (IL-10). There are over 2000 trials investigating PD-L1 and/or its receptor programmed-death 1 (PD-1) blockade in cancer, leading to the approval of PD-1 or PD-L1 inhibitors in several types of solid cancers and in hematological malignancies. The available data suggest that the molecule PD-L1 on antigen-presenting cells suppresses type 1 T cell immune responses such as cytotoxicity, and that the cytokine IL-10, in addition to downregulating immune responses, increases the expression of inhibitory molecule PD-L1. We hypothesize that the manipulation of both the co-inhibitory network (with anti-PD-L1 blocking antibodies) and suppressor network (with anti-IL-10 blocking antibodies) is an attractive immunotherapeutic intervention for acute myeloid leukemia (AML) patients ineligible for standard treatment with chemotherapy and hematopoietic stem cell transplantation, and with less severe adverse reactions. The proposed combination of these two immunotherapies represents a new approach that can be readily translated into the clinic to improve the therapeutic efficacy of AML disease treatment.