Iguratimod ameliorates inflammatory responses by modulating the Th17/Treg paradigm in dextran sulphate sodium-induced murine colitis

The Mechanism of Immune Intervention by Iguratimod in Oral Lichen Planus Patients: An In Vitro Experimental Study

BACKGROUND

Oral lichen planus (OLP) is a T cell-mediated immune disease. Iguratimod (IGU) is a novel immunomodulatory agent for rheumatoid arthritis. No studies have been reported on the mechanism of IGU in the treatment of OLP, which deserves investigation.

METHODS

Samples were collected from two batches of non-erosive OLP, erosive OLP (EOLP) patients and healthy control subjects. In the first batch, the effects of IGU or the same volume of dimethyl sulfoxide (DMSO) on proliferation, apoptosis and migration of peripheral blood T lymphocytes (PBL T) were examined by CCK-8, flow cytometry and transwell assay respectively. The levels of IL-6, IL-17, TNF-α, TGF-β and IL-10 were measured by enzyme-linked immunosorbent assay. In the second batch, the percentages of Th17 and Treg cells were determined by flow cytometry in peripheral blood mononuclear cells after IGU or DMSO stimulation.

RESULTS

Compared with the control, IGU promoted apoptosis and inhibited migration, but had no significant effect on the proliferation of PBL T in OLP. IL-6, IL-17 and TNF-α were decreased in OLP. TGF-β and IL-10 showed an upward trend in the IGU-treated EOLP. IGU decreased Th17 in OLP and reduced Th17/Treg ratio in EOLP. The percentage of Treg cells showed an upregulated trend but the difference was not statistically significant.

CONCLUSION

IGU may intervene in the immune response of OLP by affecting functions of PBL T, improving the balance of Th17/Treg and regulating related cytokines.

Iguratimod Alleviates Experimental Sjögren's Syndrome by Inhibiting NLRP3 Inflammasome Activation

Iguratimod (T-614) is a compound widely used as anti-rheumatic drug. This study investigated the effect and underlying mechanism of T-614 on experimental Sjögren's syndrome (ESS). ESS mice model was established by injection of submandibular gland protein. Mice were randomly divided into control, experimental Sjögren's syndrome (ESS), ESS + T-614 (10 mg/kg), ESS + T-614 (20 mg/kg), and ESS + T-614 (30 mg/kg) groups. Human submandibular gland (HSG) were cultured with 0, 0.5, 5, or 50 μg/ml T-614 in the absence or presence of interferon-α (IFN-α). Haematoxylin and eosin (H&E) and cytokine levels were used to detect immune cells activation in submandibular glands. Apoptosis in submandibular glands tissues and cells was determined by TUNEL and flow cytometry. Apoptosis and NLRP3 inflammasome-related proteins were detected by western blotting. T-614 treatment attenuated submandibular gland damage in ESS mice. T-614 administration inhibited submandibular gland cell apoptosis in ESS mice. Furthermore, T-614 blocked inflammatory factor levels and NLRP3 inflammasome activation in the submandibular glands. In vitro, results corroborated that T-614 could protect HSG cells from IFN-α-induced cell apoptosis and inflammation by inhibiting NLRP3 inflammasome activation. Our results expounded that T-614 alleviated ESS by inhibiting NLRP3 inflammasome activation.

Iguratimod suppresses plasma cell differentiation and ameliorates experimental Sjögren's syndrome in mice by promoting TEC kinase degradation

Primary Sjögren's syndrome (pSS) is a chronic inflammatory autoimmune disease with an unclear pathogenesis, and there is currently no approved drug for the treatment of this disease. Iguratimod, as a novel clinical anti-rheumatic drug in China and Japan, has shown remarkable efficacy in improving the symptoms of patients with pSS in clinical studies. In this study we investigated the mechanisms underlying the therapeutic effect of iguratimod in the treatment of pSS. Experimental Sjögren's syndrome (ESS) model was established in female mice by immunizing with salivary gland protein. After immunization, ESS mice were orally treated with iguratimod (10, 30, 100 mg·kg-1·d-1) or hydroxychloroquine (50 mg·kg-1·d-1) for 70 days. We showed that iguratimod administration dose-dependently increased saliva secretion, and ameliorated ESS development by predominantly inhibiting B cells activation and plasma cell differentiation. Iguratimod (30 and 100 mg·kg-1·d-1) was more effective than hydroxychloroquine (50 mg·kg-1·d-1). When the potential target of iguratimod was searched, we found that iguratimod bound to TEC kinase and promoted its degradation through the autophagy-lysosome pathway in BAFF-activated B cells, thereby directly inhibiting TEC-regulated B cells function, suggesting that the action mode of iguratimod on TEC was different from that of conventional kinase inhibitors. In addition, we found a crucial role of TEC overexpression in plasma cells of patients with pSS. Together, we demonstrate that iguratimod effectively ameliorates ESS via its unique suppression of TEC function, which will be helpful for its clinical application. Targeting TEC kinase, a new regulatory factor for B cells, may be a promising therapeutic option.

Mesenchymal Stem Cells Attenuates Hirschsprung diseases - Associated Enterocolitis by Reducing M1 Macrophages Infiltration via COX-2 Dependent Mechanism

OBJECTIVE AND DESIGN

Hirschsprung disease-associated enterocolitis (HAEC) is a common life-threatening complication of Hirschsprung disease (HSCR). We aimed to investigate the effectiveness, long-term safety and the underlying mechanisms of Mesenchymal stem cells (MSCs) based therapy for HAEC.

MATERIAL OR SUBJECTS

Specimens from HSCR and HAEC patients were used to assess the inflammatory condition. Ednrb knock-out mice was used as HAEC model. MSCs was intraperitoneally transplanted into HAEC mice. The therapy effects, long-term outcome, safety and toxicity and the mechanism of MSCs on the treatment of HAEC were explored in vivo and in vitro.

RESULTS

Intestinal M1 macrophages infiltration and severe inflammation condition were observed in HAEC. After the injection of MSCs, HAEC mice showed significant amelioration of the inflammatory injury and inhibition of M1 macrophages infiltration. The expression levels of pro-inflammatory cytokines (TNF-α and IFN-γ) were decreased and anti-inflammatory cytokines (IL-10 and TGF-β) were increased. In addition, we found that effective MSCs homing to the inflamed colon tissue occurred without long-term toxicity response. However, COX-2 inhibitor could diminish the therapeutic effects of MSCs. Using MSCs and macrophages co-culture system, we identified that MSCs could alleviate HAEC by inhibiting M1 macrophages activation through COX-2-dependent MAPK/ERK signaling pathway.

CONCLUSIONS

MSCs ameliorate HAEC by reducing M1 macrophages polarization via COX-2 mediated MAPK/ERK signaling pathway, thus providing novel insights and potentially promising strategy for the treatment or prevention of HAEC.

Iguratimod ameliorates antibody-mediated rejection after renal transplant by modulating the Th17/Treg paradigm

BACKGROUND

Iguratimod (IGU) is widely used in clinical practice due to its stable anti-inflammatory effects. Our previous studies have confirmed that the proportion of Th17/Treg balance in patients taking IGU altered significantly. This study aims to explore the role of IGU in antibody-mediated rejection (ABMR) and its potential mechanisms.

METHODS

We conducted bioinformatics analysis of sequencing data from the GEO database to analyze the abundance of immune cell infiltration in transplanted kidney tissues. In vivo, IGU was intervened in a mice secondary skin transplantation model and a mice kidney transplantation ABMR model, and histological morphology of the grafts were examined by pathological staining, while relevant indicators were determined through qRT-PCR, immunohistochemistry, and enzyme-linked immunosorbent assay, observed T cell differentiation by flow cytometry, and preliminarily assessed the immunosuppressive effect of IGU. In vitro, we established Th17 and Treg cell induction and stimulation differentiation culture systems and added IGU for intervention to explore its effects on their differentiation.

RESULTS

Through bioinformatics analysis, we found that Th17 and Treg may play important roles in the occurrence and development of ABMR. In vivo, we found that IGU could effectively reduce the damage caused by ABMR to the grafts, alleviate the infiltration of inflammatory cells in the graft tissues, and reduce the deposition of C4d in the grafts. Moreover, it is also found that IGU regulated the differentiation of Th17 and Treg cells in the spleen and peripheral blood and reduced the expression of IL-17A in the grafts and serum. In addition, same changes were observed in the induction and differentiation culture system of Th17 and Treg cells in vitro after the addition of IGU.

CONCLUSION

IGU can inhibit the progression of ABMR by regulating the differentiation of Th17 and Treg cells, providing novel insights for optimizing clinical immunosuppressive treatment regimens.

The SMILE study: Study of long-term methotrexate and iguratimod combination therapy in early rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic inflammation and joint destruction. Iguratimod (IGU) is a novel conventional synthetic disease-modifying antirheumatic drugs (csDMARD) with good efficacy and safety for the treatment of active RA in China and Japan. However, the long-term effects of IGU on the progression of bone destruction or radiographic progression in patients with active RA remain unknown. We aimed to investigate the efficacy and safety of iguratimod (IGU), a combination of methotrexate (MTX) and IGU, and IGU in patients with active rheumatoid arthritis (RA) who were naïve to MTX.

METHODS

This multicenter, double-blind, randomized, non-inferiority clinical trial was conducted at 28 centers for over 52 weeks in China. In total, 911 patients were randomized (1:1:1) to receive MTX monotherapy (10-15 mg weekly, n = 293), IGU monotherapy (25 mg twice daily, n = 297), or IGU + MTX (10-15 mg weekly for MTX and 25 mg twice daily for IGU, n = 305) for 52 weeks. The patients' clinical characteristics, Simplified Disease Activity Index (SDAI), Clinical Disease Activity Index (CDAI), disease activity score in 28 joints-C-reactive protein (DAS28-CRP) level, and erythrocyte sedimentation rate (DAS28-ESR) were assessed at baseline. The primary endpoints were the proportion of patients with ≥20% improvement according to the American College of Rheumatology (ACR20) response and changes in the van der Heijde-modified total Sharp score (vdH-mTSS) at week 52.

RESULTS

The proportions of patients achieving an ACR20 response at week 52 were 77.44%, 77.05 %, and 65.87% for IGU monotherapy, IGU + MTX, and MTX monotherapy, respectively. The non-inferiority of IGU monotherapy to MTX monotherapy was established with the ACR20 (11.57%; 95% confidence interval [CI], 4.35-18.79%; P <0.001) and vdH-mTSS (-0.37; 95% CI, -1.22-0.47; P = 0.022). IGU monotherapy was also superior to MTX monotherapy in terms of ACR20 (P = 0.002) but not the vdH-mTSS. The superiority of IGU + MTX over MTX monotherapy was confirmed in terms of the ACR20 (11.18%; 95% CI, 3.99-18.37%; P = 0.003), but not in the vdH-mTSS (-0.68; 95% CI, -1.46-0.11; P = 0.091). However, the difference in the incidence rates of adverse events was not statistically significant.

CONCLUSIONS

IGU monotherapy/IGU + MTX showed a more favorable clinical response than did MTX monotherapy. IGU may have some clinical benefits over MTX in terms of radiographic progression, implying that IGU may be considered as an initial therapeutic option for patients with active RA.

TRIAL REGISTRATION

https://classic.clinicaltrials.gov/, NCT01548001.

SLAMF3 promotes Th17 differentiation and is reversed by iguratimod through JAK1/STAT3 pathway in primary Sjögren's syndrome

OBJECTIVE

The signaling lymphocytic activation molecule family of receptors (SLAMF) is involved in the activation of T cells and plays important roles in the pathogenesis of autoimmune diseases. The purpose of this study is to observe the expression of SLAMF3 on CD4 + T cells and its effect on the differentiation of T helper 17 (Th17) in primary Sjögren's syndrome (pSS). Furthermore, we found iguratimod (IGU) could effectively reverse the aberrant Th17 differentiation through JAK1/STAT3 signaling.

METHODS

Peripheral blood mononuclear cells from 40 pSS and 40 healthy control subjects were enrolled for analysis of expression of SLAMF3 on CD4 + T and Th17 cells by flow cytometry. Serum IL-17 and SLAMF3 were detected by ELISA assay. Labial biopsies from 20 pSS patients and 20 non-pSS controls were performed immunohistochemical for staining expression of CD4, IL-17, and SLAMF3. Under the priming conditions with anti-CD3/CD28 or CD3/SLAMF3 antibodies on CD4 + T cells extracted from pSS and controls, the proportion of Th17 cells in CD4 + T cells and the amount of soluble IL-17A were assessed by flow cytometry and ELISA. Furthermore, RNA sequencing was performed for the transcriptomics study. Additionally, RNA level of RORγt and IL-17A and the protein level of RORγt, p-JAK1 and p-STAT3, were detected by real-time PCR and western blot.

RESULTS

The expression levels of SLAMF3 on CD4 + T and Th17 cells in the peripheral blood and salivary glands in pSS patients were significantly elevated than that in control groups. The serum IL-17A and SLAMF3 in pSS patients were much higher compared with the control group. Although co-stimulation of CD3/SLAMF3 could promote CD4 + T cells differentiate into Th17 cells both in pSS and controls, the CD4 + T cells from pSS have a more sensitive response in Th17 differentiation with the SLAMF3 stimulation. Transcriptomics results showed the CD3/SLAMF3 stimulation caused the activation of Th17 signaling and JAK1/STAT3 pathway. Quantitative PCR and western blotting confirmed the IGU (iguratimod), which is a safe clinical drug in treatment of autoimmune diseases, effectively reversed the increased Th17 proportion, the expression levels of RORγt, pJAK1, and pSTAT3 caused by CD3/SLAMF3 stimulation.

CONCLUSION

SLAMF3 upregulates Th17 cell differentiation of CD4 + T cells and IL-17A secretion through enriching RORγt and activating the transcriptomics participating in the pathogenesis of primary Sjögren's syndrome. IGU could inhibit the process through this therapeutic target in pSS.

Effects of iguratimod on inflammatory factors and apoptosis of submandibular gland epithelial cells in NOD mice

Non-obese diabetic (NOD) mice were taken as primary Sjögren's syndrome (pSS) model mice to examine the therapeutic impact of iguratimod (IGU) on inflammatory factors levels and apoptosis of submandibular epithelial cells, and provide experimental basis for the treatment of pSS by iguratimod. Twenty-four NOD murine models were divided into the model, high-dose (IGU 30 mg/kg) and low-dose (IGU 10 mg/kg) groups, eight mice per group. The normal control group comprised eight C57B/L mice. From 8 weeks of age, the NOD mice were administered IGU by intragastric gavage administration every day for 8 weeks; their water consumption, saliva secretion, submandibular gland, and spleen indices were measured. The levels of serum inflammatory factor (IL-1β, TNF-α, IL-6, and IL-17) were evaluated, and Bax, caspase-3, and Bcl-2 levels were detected. The histological alterations in the submandibular glands were discovered. IGU can reduce the water intake of NOD mice (p < 0.01), increase the saliva secretion and the submandibular gland index (p < 0.01); reduce the spleen index and the serum inflammatory factors (p < 0.01); improve the pathological tissue damage and cell apoptosis of the submandibular gland (p < 0.05). IGU can reduce the expression levels of inflammatory mediators in the serum and the extent of lymphocyte infiltration and apoptosis in submandibular gland epithelial cells. It can also regulate apoptosis-related protein expression, thereby improving the secretory function of exocrine glands.

Iguratimod promotes functional recovery after SCI by repairing endothelial cell tight junctions

Destruction of the blood-spinal cord barrier (BSCB) after spinal cord injury (SCI) is an important factor promoting the progression of the injury. This study addressed how to repair the BSCB in order to promote the repair of injured spinal cords. Iguratimod (IGU), an anti-rheumatic drug, has been approved for clinical use. A spinal cord injury mouse model and TNF-α-stimulated bEnd.3 cells were used to investigate the effect and mechanism of IGU on injured BSCB. An intracerebroventricular osmotic pump was used to administer drugs to the SCI mouse model. The results showed that the SCI mice in the treatment group had better recovery of neurological function than the control group. Examination of the tissue revealed better repair of the BSCB in injured spinal cords after medication. According to the results from the cell model, IGU promoted the expression of tight junction proteins and reduced cell permeability. Further research found that IGU repaired the barrier function by regulating glycolysis levels in the injured endothelial cells. In studying the mechanism, IGU was found to regulate HIF-1α expression through the NF-κB pathway, thereby regulating the expression of the glycolytic enzymes related to endothelial injury. In summary, IGU promoted functional recovery in vivo by repairing the BSCB. In vitro, IGU regulated the level of glycolysis in the damaged endothelium through the NF-κB pathway, thereby repairing the tight junctions between the endothelium. Therefore, IGU may become a potential drug for treating spinal cord injury.

Research progress on the clinical application and mechanism of iguratimod in the treatment of autoimmune diseases and rheumatic diseases

Autoimmune diseases are affected by complex pathophysiology involving multiple cell types, cytokines, antibodies and mimicking factors. Different drugs are used to improve these autoimmune responses, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antibodies, and small molecule drugs (DMARDs), which are prevalent clinically in the treatment of rheumatoid arthritis (RA), etc. However, low cost-effectiveness, reduced efficacy, adverse effects, and patient non-response are unattractive factors driving the development of new drugs such as iguratimod. As a new disease-modifying antirheumatic drug, iguratimod has pharmacological activities such as regulating autoimmune disorders, inflammatory cytokines, regulating immune cell activation, differentiation and proliferation, improving bone metabolism, and inhibiting fibrosis. In recent years, clinical studies have found that iguratimod is effective in the treatment of RA, SLE, IGG4-RD, Sjogren 's syndrome, ankylosing spondylitis, interstitial lung disease, and other autoimmune diseases and rheumatic diseases. The amount of basic and clinical research on other autoimmune diseases is also increasing. Therefore, this review systematically reviews the latest relevant literature in recent years, reviews the research results in recent years, and summarizes the research progress of iguratimod in the treatment of related diseases. This review highlights the role of iguratimod in the protection of autoimmune and rheumatic bone and related immune diseases. It is believed that iguratimod's unique mode of action and its favorable patient response compared to other DMARDs make it a suitable antirheumatic and bone protective agent in the future.

Taurohyodeoxycholic acid alleviates trinitrobenzene sulfonic acid induced ulcerative colitis via regulating Th1/Th2 and Th17/Treg cells balance

AIMS

Taurohyodeoxycholic acid (THDCA), a natural 6α-hydroxylated bile acid, exhibits intestinal anti-inflammatory effects. This study aimed to explore the efficacy of THDCA on ulcerative colitis and to reveal its mechanisms of action.

MAIN METHODS

Colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS) to mice. Mice in the treatment group were gavage THDCA (20, 40, and 80 mg/kg/day) or sulfasalazine (500 mg/kg/day) or azathioprine (10 mg/kg/day). The pathologic markers of colitis were comprehensively assessed. The levels of Th1-/Th2-/Th17-/Treg-related inflammatory cytokines and transcription factors were detected by ELISA, RT-PCR, and Western blotting. The balance of Th1/Th2 and Th17/Treg cells was analyzed by Flow cytometry.

KEY FINDINGS

THDCA significantly alleviated colitis by improving the body weight, colon length, spleen weight, histological characteristics, and MPO activity of colitis mice. THDCA reduced the secretion of Th1-/Th17-related cytokines (IFN-γ, IL-12p70, IL-6, IL-17A, IL-21, IL-22, and TNF-α) and the expressions of transcription factors (T-bet, STAT4, RORγt, and STAT3), but increase the production of Th2-/Treg-related cytokines (IL-4, IL-10, and TGF-β1) and the expressions of transcription factors (GATA3, STAT6, Foxp3, and Smad3) in the colon. Meanwhile, THDCA inhibited the expressions of IFN-γ, IL-17A, T-bet, and RORγt, but improved the expression of IL-4, IL-10, GATA3, and Foxp3 in the spleen. Furthermore, THDCA restored the proportion of Th1, Th2, Th17, and Treg cells, and balanced the Th1/Th2 and Th17/Treg immune response of colitis mice.

SIGNIFICANCE

THDCA can alleviate TNBS-induced colitis via regulating Th1/Th2 and Th17/Treg balance, which may represent a promising treatment for patients with colitis.

Regulatory Effect of JAK2/STAT3 on the Immune Function of Endotoxin-tolerant Dendritic Cells and its Involvement in Acute Liver Failure

BACKGROUND AND AIMS

Acute liver failure (ALF) is a potentially fatal clinical syndrome with no effective treatment. This study aimed to explore the role of Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway in modulating the phenotype and immune function of endotoxin-tolerant dendritic cells (ETDCs). In addition, we explored the use of EDTCs in an experimental model of ALF and investigated the associated mechanisms.

METHODS

In the in vitro experiment, ETDCs were transfected with adenovirus to induce SOCS1+/+ETDCs and SOCS1-/-ETDCs. Thereafter, costimulatory molecules and mixed lymphocyte reaction were assessed. Experimental mice were randomly divided into normal control, ALF, ALF+mock-ETDCs, ALF+SOCS1+/+ETDCs, ALF+AG490, and ALF+AG490+SOCS1+/+ETDCs groups. We examined the therapeutic effect of adoptive cellular immunotherapy by tail-vein injection of target ETDCs 12 h before ALF modeling. AG490, a JAK2/STAT3 inhibitor, was used in the in vivo experiment to further explore the protective mechanism of SOCS1+/+ETDCs.

RESULTS

Compared with control ETDCs, SOCS1+/+ETDCs had lower expression of costimulatory molecules, weaker allostimulatory ability, lower levels of IL-6 and TNF-α expression and higher IL-10 secretion. SOCS1-/-ETDCs showed the opposite results. In the in vivo experiments, the ALF+SOCS1+/+ETDCs and ALF+AG490+SOCS1+/+ETDCs groups showed less pathological damage and suppressed activation of JAK2/STAT3 pathway. The changes were more pronounced in the ALF+AG490+SOCS1+/+ETDCs group. Infusion of SOCS1+/+ETDCs had a protective effect against ALF possibly via inhibition of JAK2 and STAT3 phosphorylation.

CONCLUSIONS

The SOCS1 gene had an important role in induction of endotoxin tolerance. SOCS1+/+ETDCs alleviated lipopolysaccharide/D-galactosamine-induced ALF by downregulating the JAK2/STAT3 signaling pathway.

Iguratimod alleviates tubulo-interstitial injury in mice with lupus

INTRODUCTION

Tubulo-interstitial injury is a poor prognostic factor for lupus nephritis (LN). Here, we tested whether iguratimod could inhibit tubulo-interstitial injury in LN.

METHODS

MRL/lpr mice, an animal model of lupus, were treated with iguratimod or vehicle solution. Pathological changes of kidney were evaluated blindly by the same pathologist. Renal type I collagen (COL-I), IgG, E-cadherin, fibroblast-specific protein 1 (FSP-1) were detected by immunofluorescence, immunohistochemical staining or quantitative real-time PCR. After treated with transforming growth factor β1 (TGF-β1) and iguratimod, E-cadherin, fibronectin, Smad2/3, p38 MAPK, p-Smad2/3, and p-p38 MAPK, β-catenin and TGF-β type II receptor (TGFβRII) in HK2 cells were measured by western blotting, quantitative real-time PCR or immunofluorescence.

RESULTS

Iguratimod reduced immune deposition along the tubular basement membrane, inhibited the tubulo-interstitial infiltration of inflammatory cells, and alleviated tubular injury in MRL/lpr mice. Moreover, Iguratimod eased the tubulo-interstitial deposition of collagen fibers, which was confirmed by decreased expression of COL-I. Furthermore, iguratimod suppressed the expression of FSP-1 and increased that of E-cadherin in renal tubular epithelial cells. In HK2 cells cultured with TGF-β1, iguratimod treatment not only reversed cellular morphological changes, but also prevented E-cadherin downregulation and fibronectin upregulation. In addition, iguratimod inhibited phosphorylation of TGFβRII, Smad2/3 and p38 MAPK in HK2 cells treated with TGF-β1, and also blocked nuclear translocation of β-catenin.

CONCLUSION

Iguratimod eased tubulo-interstitial lesions in LN, especially tubulo-interstitial fibrosis, and might have potential as a drug for inhibiting the progression of tubulo-interstitial fibrosis in LN.

Yiqi Jiedu herbal decoction attenuates the 2 Gy 60Co γ ray induced spleen injury by inhibiting apoptosis and modulating the immune balance

ETHNOPHARMACOLOGICAL RELEVANCE

Irradiation-induced immunosuppression often occurs during radiotherapy in patients, which would increase the risk of opportunistic infections. Many Chinese herbal prescriptions or natural extracts have recently attracted increased radiation protection and therapy attention due to their low toxicity.

AIM OF THE STUDY

The present study aimed to investigate the protective effects of Yiqi Jiedu (YQJD) decoction on spleen injury induced by 2 Gy ⁶⁰Co γ ray in mice.

MATERIALS AND METHODS

A total of 180 Balb/c mice were randomly divided into five groups: blank control (Ctrl), model (IR), positive drug (IRA), low-dose YQJD decoction (IRL), and high-dose YQJD decoction (IRH). After a ten-day intervention, mice were exposed to a single dose of total body irradiation (2 Gy) and sacrificed on the 1^st, 3^rd, and 7^th day after irradiation. The indicators include general observations and body weight, changes in peripheral hemogram, index and histopathology examination of the spleen, distribution of lymphocyte subsets, cytokine levels, and apoptosis in the spleen.

RESULTS

In comparison to the Ctrl group, the body weight, spleen index, peripheral blood cell, and splenocyte quantities decreased significantly after exposure, accompanied by a notable increase of apoptosis in spleen cells. Moreover, ionizing radiation also broke the balance of CD4+/CD8+, Th1/Th2, and Th17/Treg, triggering immune imbalance and immunosuppression. The above injuries occurred on the 1^st day after exposure, worsened on the 3^rd, and were relieved on the 7^th day. However, the pretreatment of YQJD decoction increased the spleen index, improved the spleen structure, and inhibited radiation-induced apoptosis after exposure. Additionally, YQJD decoction has shown its ability to promote immunological balance recovery following exposure by regulating CD4+/CD8+, Th1/Th2, and Th17/Treg ratios, which may minimize the risk of infection. In addition, the high-dose of YQJD decoction showed a better protective effect than the low-dose group.

CONCLUSION

The protective effects of YQJD decoction on 2 Gy ⁶⁰Coγray induced spleen injury were confirmed in this study. This mechanism may be related to inhibiting apoptosis and modulating immune balance. This exploration might provide new insights into the use of Chinese herbs on radioprotection of the immune system.

Efficacy and Safety of Iguratimod Supplement to the Standard Immunosuppressive Regimen in Highly Mismatched Renal Transplant Recipients: A Pilot Study

Iguratimod (IGU) can mitigate the symptoms of rheumatoid arthritis through its anti-inflammatory effects. The objective of this study was to investigate the clinical efficacy and safety of IGU in highly HLA-mismatched renal transplant recipients, in combination with standard immunosuppressive regimen. This pilot study was designed as an open-label, blank-control, randomized clinical trial on patients recruited from a single transplant center in China. Patients who met the inclusion criteria were randomized to the IGU (n=27) and blank control (n=27) groups. IGU was administrated with the conventional triple immunosuppressive protocol for 52 weeks after kidney transplantation. The incidence of biopsy-proven acute rejection rate was 14.8% (4/27) in the IGU group and 29.6% (8/27) in the control group, P = 0.19. The clinical rejection rate was also substantially reduced in the IGU group (3.7% vs. 18.5%, P = 0.08). De novo donor-specific antibody also showed a decline trend in the IGU group after 52 weeks. The graft function and incidence of adverse events were similar between the two groups. In addition, IGU intervention significantly decreased the number of NK cells throughout the follow-up. In conclusion, our study has shown the possibility that IGU could reduce the allograft rejection rate and de novo DSA with appreciable safety in combination with conventional immunosuppressants. Formal clinical trials were warranted based on current findings.

VX765 alleviates dextran sulfate sodium-induced colitis in mice by suppressing caspase-1-mediated pyroptosis

Inflammatory bowel disease (IBD) is an autoimmune disease involving intestinal tissue. IBD activates a series of cell death pathways. Pyroptosis is recently identified as a critical cell death pathway in IBD associated with the activation of caspase-1. VX765 is a caspase-1 inhibitor that can be converted to VRT-043198 in vivo. This study was designed to explore the therapeutic effect of VX765 on colitis using a dextran sulfate sodium (DSS)-induced colitis model in mice. In this research, the caspase-1 inhibitor on inflammatory, pyroptosis, apoptosis, macrophage activation, and intestinal barrier were investigated. We found that administration of VX765 attenuated body weight loss, colonic shortening, and colonic pathological injury in mice. Our study also revealed a therapeutic effect of VX765 on colitis in a dose-dependent manner. VX765 inhibited pyroptosis by curbing the Caspase-1/GSDMD pathway and its downstream key inflammatory cytokines--IL-1β and IL-18. These results indicated that VX765 might have a dose-dependent therapeutic effect on DSS-induced colitis in mice.

Iguratimod Alleviates Myocardial Ischemia/Reperfusion Injury Through Inhibiting Inflammatory Response Induced by Cardiac Fibroblast Pyroptosis via COX2/NLRP3 Signaling Pathway

Background: NLRP3 inflammasome contributes a lot to sterile inflammatory response and pyroptosis in ischemia/reperfusion (I/R) injury. Cardiac fibroblasts (CFs) are regarded as semi-professional inflammatory cells and they exert an immunomodulatory role in heart. Iguratimod provides a protective role in several human diseases through exerting a powerful anti-inflammatory effect. However, it is still unclear whether iguratimod could alleviate myocardial I/R injury and whether inflammation triggered by NLRP3-related pyroptosis of CFs is involved in this process. Methods: Transcriptomics analysis for GSE160516 dataset was conducted to explore the biological function of differentially expressed genes during myocardial I/R. In vivo, mice underwent ligation of left anterior descending coronary artery for 30 min followed by 24 h reperfusion. In vitro, primary CFs were subjected to hypoxia for 1 h followed by reoxygenation for 3 h (H/R). Iguratimod was used prior to I/R or H/R. Myocardial infarct area, serum level of cardiac troponin I (cTnI), pathology of myocardial tissue, cell viability, lactate dehydrogenase (LDH) release, and the expression levels of mRNA and protein for pyroptosis-related molecules were measured. Immunofluorescence was applied to determine the cellular localization of NLRP3 protein in cardiac tissue. Results: During myocardial I/R, inflammatory response was found to be the most significantly enriched biological process, and nucleotide-binding oligomerization domain (NOD)-like receptor signaling was a crucial pathway in mediating cardiac inflammation. In our experiments, pretreatment with iguratimod significantly ameliorated I/R-induced myocardial injury and H/R-induced pyroptosis of CFs, as evidenced by reduced myocardial infarct area, serum cTnI level, and LDH release in supernatants, as well as improved pathology of cardiac tissue and cell viability. Immunofluorescence analysis showed that NLRP3 was mainly localized in CFs. Moreover, iguratimod inhibited the expression of pro-inflammatory cytokines and pyroptosis-related molecules, including NLRP3, cleaved caspase-1, and GSDMD-N. Conclusion: Our results suggested that inflammatory response mediated by NOD-like receptor signaling is of vital importance in myocardial I/R injury. Iguratimod protected cardiomyocytes through reducing the cascade of inflammation in heart by inhibiting cardiac fibroblast pyroptosis via the COX2/NLRP3 signaling pathway.

Efficacy and safety of iguratimod combined with methotrexate vs. methotrexate alone in rheumatoid arthritis : A systematic review and meta-analysis of randomized controlled trials

The current systematic review and meta-analysis aims to evaluate the efficacy and safety of iguratimod (IGU) combined with methotrexate (MTX) versus MTX alone in rheumatoid arthritis (RA). Two independent investigators searched for original randomized controlled trials (RCTs) related to the combination of IGU and MTX in RA published before November 1, 2019, in PubMed, Cochrane Library, Embase, the China National Knowledge Infrastructure (CNKI), the Chinese Biomedical Literature Database (CBM), and WanFang Data. Additionally, we searched clinical trial registry websites. We assessed the methodological quality of the included trials using the Cochrane Collaboration tool and the seven-point Jadad scale. Statistical analyses were performed using Review Manager (RevMan) 5.3 (Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014). Meta-regression and publication bias analyses were performed using Stata version 14 software (StataCorp., College Station, TX, USA). A total of 7 RCTs consisting of 665 participants, with 368 participants in the active arm and 297 in the placebo arm, were included in the meta-analysis. The American College of Rheumatology (ACR) value was better in the IGU + MTX group than in the MTX alone group, with a pooled relative risk (RR) for ACR20 (American College of Rheumatology 20% improvement criteria), ACR50, and ACR70 of 1.40 (95% CI, 1.13-1.74), 2.09 (95% CI, 1.67-2.61), and 2.24 (95% CI, 1.53-3.28), respectively. The results of the meta-analysis demonstrated that there was no statistical significance in adverse events (1.06 (95% CI, 0.92-1.23)). The combined treatment is an effective, safe, and economical treatment option for patients who do not respond well to methotrexate alone or for patients who cannot afford expensive biologics that have no confirmed efficacy.

Iguratimod: Novel Molecular Insights and a New csDMARD for Rheumatoid Arthritis, from Japan to the World

Iguratimod (IGU) is a conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) routinely prescribed in Japan since 2012 to patients with rheumatoid arthritis (RA). Iguratimod acts directly on B cells by inhibiting the production of inflammatory cytokines (tumor necrosis factor-α, interleukin (IL)-1β, IL-6, IL-8, IL-17), thereby suppressing the production of immunoglobulin and inhibiting the activity of nuclear factor kappa-light chain enhancer of activated B cells. In Japan, it is one of the most used csDMARDs in daily practice, but it is not recommended as a treatment for RA due to the lack of large-scale evidence established overseas. However, recent reports on the novel pharmacological effects of IGU on lymphocytes and synovial fibroblasts, as well as its efficacy in daily practice, have increased its importance as a drug for the treatment of RA. In this review, we highlighted the basic and clinical studies in IGU and discuss its potential as a new therapeutic agent for the treatment of RA.

Juglone regulates gut microbiota and Th17/Treg balance in DSS-induced ulcerative colitis

Juglone, mainly isolates from the green walnut husks of Juglans mandshurica, exhibits anti-cancer and anti-inflammaroty activities. But its protection on ulcerative colitis (UC) has never been explored. In this study, we first evaluated whether juglone ameliorated UC, and investigated its effects on gut microbiota and Th17/Treg balance in DSS-induced UC mice model. The model was established by administrating 2.7% DSS for seven days. Juglone was given daily by gavage for ten days, once a day. The disease activity index (DAI) decrease and pathological characteristics improvement demonstrated that the UC in mice was alleviated by juglone. Juglone treatment significantly inhibited the protein levels of IL-6, TNF-α and IL-1β, improved the protein expression of IL-10. In addition, juglone altered microbial diversity and gut microbiota composition, including the enhancement of the ratio of Firmicutes to Bacteroidota and the abundance of Actinobacteriota, and decrease of the abundance of Verrucomicrobiota. Juglone treatment also inhibited the protein expressions of IL-6, STAT3 and RORγt, meanwhile improved the protein level of FOXP3. Furthermore, juglone inhibited Th17 development and increased Treg generation, beneficial to Th17/Treg balance. Together, we herein provided the first evidence to support that juglone, especially the high dose, possibly protected mice against UC by modulating gut microbiota and restoring Th17/Treg homeostasis.

Anti-fibrotic effect of iguratimod on pulmonary fibrosis by inhibiting the fibroblast-to-myofibroblast transition

PURPOSE

Pulmonary fibrosis (PF) is a severe lung disease causing significant morbidity and mortality. PF pathogenesis is attributed to the fibroblast-to-myofibroblast transition (FMT) driven by the most potent pro-fibrogenic factor TGF-β1 activating the Smad3-dependent TGF-β1 canonical pathway. Iguratimod (IGU) is a novel anti-rheumatic drug that suppresses the secretion of inflammatory factors, but is also able to modulate the differentiation of multiple cells. Therefore, the aim of this work was to investigate the effect of IGU on FMT.

MATERIALS/METHODS

PF mouse model was induced in C57BL/6 male mice by bleomycin. The effect of IGU was assessed through the evaluation of lung morphology by H&E and through the collagen accumulation in the lung by Masson staining. Primary human lung fibroblasts (pHLFs) were also used to evaluate the effect of IGU in vitro on TGF-β1-stimulated cells, and proliferation, migration and invasion were measured, together with genes and proteins involved in FMT.

RESULTS

IGU attenuated bleomycin-induced PF in mice and improved the pathological changes in their lungs. In addition, IGU significantly inhibited proliferation, migration and invasion in TGF-β1-stimulated pHLFs without causing apoptosis. Moreover, IGU significantly reduced TGF-β1-induced increase of collagen I and III mRNA expression, thus reducing lung function impairment, and α-SMA, Smad2 and Smad3 phosphorylation, fibronectin expression and F-actin microfilament formation, thus attenuating FMT through the inhibition of the Smad3 pathway.

CONCLUSIONS

Our results collectively revealed the beneficial effect of IGU on the inhibition of FMT, thus suggesting that it might act as an effective anti-fibrotic agent in preventing the progression of PF.

TAK-242 ameliorates DSS-induced colitis by regulating the gut microbiota and the JAK2/STAT3 signaling pathway

BACKGROUND

The goal of the present study was to investigate the effects of TAK-242 on the gut microbiota and the TLR4/JAK2/STAT3 signaling pathway in mice with dextran sulfate sodium (DSS)-induced colitis.

RESULTS

At the phylum level, Bacteroidetes, Firmicutes, Actinobacteria, Cyanobacteria, Epsilonbacteraeota and Proteobacteria were the primary microbiota in the five groups. TAK-242 treatment significantly enhanced Verrucomicrobia and Actinobacteria; significantly decreased Cyanobacteria, Epsilonbacteraeota and Proteobacteria; and particularly promoted the growth of Akkermansia. TAK-242 markedly alleviated DSS-induced colitis symptoms and colonic lesions by promoting IL-10 release, inhibiting IL-17 release, downregulating TLR4 and JAK2/STAT3 mRNA and protein expression and increasing JAK2/STAT3 phosphorylation.

CONCLUSION

TAK-242 modulates the structure of the gut microbiota in colitis and may be a novel therapeutic candidate for ulcerative colitis.

Functional Immunoregulation by Heme Oxygenase 1 in Juvenile Autoimmune Diseases

An autoimmune disease is an inflammatory condition in which the human body's immune system attacks normal cells, resulting in decreased and abnormal immune function, which eventually leads to tissue damage or organ dysfunction. In the field of medicine, especially in pediatrics, knowledge about autoimmune diseases is still inadequate. Some common juvenile autoimmune diseases such as Henoch-Schonlein purpura, systemic juvenile idiopathic arthritis, mucocutaneous lymph node syndrome, and autoimmune encephalitis cause considerable public concern. Recent studies revealed that heme oxygenase 1 (HO-1), an enzyme that participates in heme degradation, plays a critical role in the pathogenesis and may regulate autoimmunity. Firstly, it may promote the differentiation of T lymphocytes into CD4+CD25+ regulatory T cells and may be associated with changes in the ratios of cytokines (Th1/Th2 and Th17/Treg) as well. Secondly, HO-1 can regulate the immune system through the secretion of proteins such as transforming growth factors and interleukins. Moreover, increasing the expression of HO-1 can improve vascular function by increasing antioxidant levels. Thus, HO-1 may provide a theoretical basis and guidance for therapeutic management of juvenile autoimmune diseases.

The Chinese medicinal herb decoction QRZSLXF enhances anti-inflammatory effect in TNBS-induced colitis via balancing Th17/Tregs differentiation

ETHNOPHARMACOLOGICAL RELEVANCE

Inflammatory bowel disease (IBD) is one of the most common chronic inflammatory illnesses of the gastrointestinal tract due to the imbalance of immune homeostasis of T helper cells and/or regulatory T cells (Tregs). The Traditional Chinese medicine herb has been clinically proven for use in the treatment of IBD but its possible mechanism remains unknown. The study aims to assess the effect of Chinese medicinal herb decoction QRZSLXF (Qing Re Zao Shi Liang Xue receipt) for the treatment of TNBS-induced experimental colitis in mice and explore its relevant mechanism involved in Th17 and Tregs.

MATERIALS AND METHODS

Mice colitis was induced by 50% 2,4,6-Trinitrobenzenesulfonic Acid (TNBS) ethanol solution weekly manner. These established model mice were divided into model control (0.8% NaCl treatment), FICZ, naphthoflavone (NaFTV), dexamethasone (DXM), and QRZSLXF (QrLx) groups. The colonoscopy, H&E staining, and immune staining were used to analyze the disease severity, inflammatory condition and Th17 or Treg related factors expression. High-performance liquid chromatography-mass spectrometry (HPLC/MS) was used to assess the content of FICZ in the colon tissues. Western blot and ELISA were used to examine the expression of Th17 or Treg related factors protein levels. Flow cytometry analysis was performed to assess the number and ratio of Th17/Tregs in splenocytes, and mesenteric lymph node lymphocytes (MLNCs), and lamina propria mononuclear cells (LPMCs).

RESULTS

NaFTV, DXM and QrLx groups intestinal inflammation scores were significantly lower than that in colitis model control and FICZ groups, while the IL-6, STAT3, and RORγt expression levels were significantly lower than those in the model control and FICZ groups. Mass spectrometry results showed FICZ that in both DXM and QrLx groups was lower than control model and FICZ groups. Flow cytometry results showed that DXM, NaFTV and QrLx could significantly reduce Th17 proportion and increase Treg proportion in splenocytes, MLNCs, and LPMCs.

CONCLUSIONS

NaFTV and QrLx treatment could decrease symptoms and inflammatory colitis, by decreasing of FICZ concentration and AhR signaling in colon, resulting in reducing the expression of IL-6, STAT3, and RORγt, whereas increasing the expression of FOXP3, consequently reducing the proportion of Th17 cells and increasing the proportion of Treg cells, respectively.

Iguratimod as a New Drug for Rheumatoid Arthritis: Current Landscape

Iguratimod (IGU) is a novel synthetic small molecule disease modified anti-rheumatic drug approved only in Japan and China up to date. IGU plays an important immunomodulatory role in the synovial tissue of rheumatoid arthritis by inhibiting the production of immunoglobulins and cytokines and regulating T lymphocyte subsets. IGU also regulates bone metabolism by stimulating bone formation while inhibiting osteoclast differentiation, migration, and bone resorption. In clinical trials, IGU was shown to be superior to placebo and not inferior to salazosulfapyridine. Combined therapy of IGU with other disease-modifying anti-rheumatic drugs showed significant improvements for disease activity. IGU has good efficacy and tolerance as an additional treatment for rheumatoid arthritis patients with inadequate response to methotrexate and biological disease-modifying anti-rheumatic drugs. In this review, we summarize current landscape on the mechanism of action of IGU and its clinical effectiveness and safety. It is expected that further translational studies on IGU will pave the road for wider application of IGU in the treatment of autoimmune diseases other than rheumatoid arthritis.

Saikosaponin-d ameliorates dextran sulfate sodium-induced colitis by suppressing NF-κB activation and modulating the gut microbiota in mice

Saikosaponin-d (SSd), extracts from Bupleurum falcatum L, exhibits anti-inflammatory and anti-infectious activities. However, the effect of SSd on intestinal inflammation has not been investigated. The aim of this study was to evaluate the effect of SSd on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice, and to elucidate the underlying mechanisms. UC was induced in mice by administrating 3% DSS in drinking water for 7 days. SSd (4 mg/kg and 8 mg/kg) was administered by gavage every day during the experimental process. The results showed that SSd treatment (8 mg/kg) significantly ameliorated UC mice by decreasing disease activity index (DAI), increasing colon length and improving pathological characteristics. SSd treatment (8 mg/kg) significantly suppressed the mRNA levels of pro-inflammatory cytokines including TNF-α, IL-6 and IL-1β, increased that of anti-inflammatory cytokine IL-10. Furthermore, SSd (8 mg/kg) suppressed the activation of NF-κB by decreasing the degradation and phosphorylation of IκB. SSd (8 mg/kg) also protected the intestinal barrier by increasing the mRNA levels of mucin (Muc1 and Muc2) and the protein levels of zonula occludens-1 (ZO-1) and Claudin-1. The 16S rDNA gene high-throughput sequencing revealed that SSd treatment (8 mg/kg) increased the alpha diversity and regulated the structure of gut microbiota in UC mice. Taken together, our findings demonstrated that SSd (8 mg/kg) improved DSS-induced intestinal inflammation by inhibiting NF-κB activation and regulated the gut microbiota.

FGL2 regulates IKK/NF-κB signaling in intestinal epithelial cells and lamina propria dendritic cells to attenuate dextran sulfate sodium-induced colitis

Inflammatory bowel disease (IBD) is an autoimmune disease characterized by an abnormal immune response. Fibrinogen-like protein 2 (FGL2) is known to have immunoregulatory and anti-inflammatory activity. The level of FGL2 is elevated in patients with IBD; however, its comprehensive function in IBD is almost unknown. In our study, we explored the effect of FGL2 on dextran sulfate sodium (DSS)-induced colitis in mice and on NF-κB signaling in intestinal epithelial cells (IECs) and lamina propria dendritic cells (LPDCs). We founded that FGL2^-/- mice in the colitis model showed more severe colitis manifestations than WT mice did, including weight loss, disease activity index (DAI), and colon histological scores. FGL2^-/- mice treated with DSS produced more proinflammatory cytokines (IL-1β, IL-6, TNF-α) in serum than WT mice did and demonstrated upregulated expression of TNF-α and inflammatory marker enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (Cox-2) in the colon tissue. Our data suggested that DSS-treated FGL2^-/- mice showed stronger activation of NF-κB signaling, especially in IECs. Next, we demonstrated that recombinant FGL2 (rFGL2) inhibited the production of proinflammatory cytokines and the expression of inflammatory marker enzymes by downregulating the NF-κB signaling in HT-29 cells. Finally, we discovered that LPDCs from the colon of DSS-treated FGL2^-/- mice showed significantly upregulated expression of surface maturation co-stimulatory molecules, including CD80, CD86, CD40, and MHC class II molecules compared with that in WT mice. In addition, LPDCs in FGL2^-/- treated with DSS exhibited excessive NF-κB activity and the administration of rFGL2 to FGL2^-/- mice could rescue the aggravated results of FGL2^-/- mice. Taken together, our findings demonstrated that FGL2 might be a target for further therapy of IBD.

Iguratimod (T-614) attenuates severe acute pancreatitis by inhibiting the NLRP3 inflammasome and NF-κB pathway

Severe acute pancreatitis (SAP) is an acute abdominal disease that can develop locally to the multiple organs. It is characterized by pancreatic tissue self-digestion, and the rapid release of inflammatory cytokines, which play a dominant role in local or even systemic inflammation. In this study, we investigate the protective effect of T-614 against SAP induced by cerulein plus LPS in mice. Biochemical markers associated with pancreatitis in serum such as inflammatory cytokines, amylase and lipase activities were measured. Related proteins of NLRP3 inflammasome and NF-κB signaling pathway were evaluated by western blotting. Hematoxylin-eosin staining (HE) and immunohistochemistry (IHC) were used to evaluate changes of inflammation in pancreatic tissue. T-614 significantly alleviated the elevation markers of pancreatitis and suppresses the pancreatic tissue damage, including histopathological and molecular manifestations. In conclusion, T-614 plays a protective role in experimental SAP mice model via anti-inflammatory effects.

Iguratimod: a valuable remedy from the Asia Pacific region for ameliorating autoimmune diseases and protecting bone physiology

Autoimmune diseases are affected by complex pathophysiology involving several cell types, cytokines, antibodies, and mimicking factors. Different drugs are used to ameliorate these autoimmune reactions, including nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antiantibodies, and small molecular drugs (DMARDs), and they are clinically in vogue for diseases such as rheumatoid arthritis (RA). Nevertheless, low cost-effectiveness, reduced efficacy, adverse effects, and patient nonresponse are unappealing factors driving the development of new drugs such as iguratimod. Iguratimod is primarily used to ameliorate RA in Japanese and Chinese clinics. However, its efficacy against other autoimmune ailments is also under intense investigation, and the number of investigations is becoming increasingly larger with each passing day. The articular structure comprises synovium, ligaments, and bone. The latter is more complex than the others since it regulates blood cells and autoimmunity in addition to providing skeletal support to the body. Therefore, its protection is also of prime importance in RA and other autoimmune diseases. Herein, we have highlighted the role of iguratimod in autoimmune diseases and bone protection. We suggest that iguratimod’s unique mode of action compared with that of other DMARDs and its good patient response makes it a suitable antirheumatic and bone-protecting drug.

Decursinol Angelate Ameliorates Dextran Sodium Sulfate-Induced Colitis by Modulating Type 17 Helper T Cell Responses

Angelica gigas has been used as a Korean traditional medicine for pain relief and gynecological health. Although the extracts are reported to have an anti-inflammatory property, the bioactive compounds of the herbal plant and the effect on T cell responses are unclear. In this study, we identified decursinol angelate (DA) as an immunomodulatory ingredient of A. gigas and demonstrated its suppressive effect on type 17 helper T (Th17) cell responses. Helper T cell culture experiments revealed that DA impeded the differentiation of Th17 cells and IL-17 production without affecting the survival and proliferation of CD4 T cells. By using a dextran sodium sulfate (DSS)-induced colitis model, we determined the therapeutic potential of DA for the treatment of ulcerative colitis. DA treatment attenuated the severity of colitis including a reduction in weight loss, colon shortening, and protection from colonic tissue damage induced by DSS administration. Intriguingly, Th17 cells concurrently with neutrophils in the colitis tissues were significantly decreased by the DA treatment. Overall, our experimental evidence reveals for the first time that DA is an anti-inflammatory compound to modulate inflammatory T cells, and suggests DA as a potential therapeutic agent to manage inflammatory conditions associated with Th17 cell responses.

Rhubarb Peony Decoction ameliorates ulcerative colitis in mice by regulating gut microbiota to restoring Th17/Treg balance

ETHNOPHARMACOLOGY RELEVANCE

Rhubarb Peony Decoction (RPD) is a formula of traditional Chinese medicine chronicled in Jin Gui Yao Lve, commonly used to treat ulcerative colitis (UC). However, the underlying mechanism of RPD treating UC remains elusive. In our study, we investigated the therapeutic efficacy of RPD and potential mechanism involved in inhibiting dextran sulfate sodium (DSS)-induced ulcerative colitis in mice.

METHODS

The colitis was induced by DSS in mice for 5 days and estimated body weight loss, disease activity index (DAI) and colon length. Histological changes were observed by H&E staining. The number and abundance of gut mircrobiota were measured with 16 S rDNA sequencing. GC-MS was used to detect the concentration of short chain fatty acids (SCFAs) in cecum. Flow cytometry analyzed the proportion of Th17 and Treg cells in mesenteric lymph nodes (MLNs). IL-17A and Foxp3 in colon were determined by immunohistochemical analyses. The level of cytokine was determined by Multi-Analyte Flow Assay Kit.

RESULTS

Administration of RPD significantly alleviated the pathological changes of UC mice, involving rescued the inflammation-related reduction of colon length, ameliorated body weight loss and damaged tissue. In addition, RPD altered the gut microbiota, involving restored α diversity, increased significantly the abundance of Firmicutes and Actinobacteria, decreased the Proteobacteria and Bacteroidetes. Furthermore, the number of Butyricicoccus pullicaecorum, a butyrate-producing bacterium, were augmented obviously by RPD. Besides, RPD restored the content of SCFA in intestinal tract. Additionally, the proportion of Th17 cells and Treg cells in mesenteric lymph nodes, likewise, the expression of IL-17A and Foxp3 in colon were regulated by RPD, contributing to the restoration of Th17/Treg balance. Moreover, RPD significantly decreased the level of IL-6, TNF-α, IFNγ, IL-10, IL-17A, IL-21, IL-22 in colon, simultaneously increased Treg-related cytokine TGF-β at dose-dependently.

CONCLUSIONS

These results demonstrated that RPD had effect on ulcerative colitis, which was related to regulating gut microbiota, especially Butyricicoccus pullicaecorum, and SCFAs to restore the gut Th17/Treg homeostasis.