Runx1-deficient afferents impair visceral nociception, exacerbating dextran sodium sulfate-induced colitis

TRAF5 regulates intestinal mucosal Th1/Th17 cell immune responses via Runx1 in colitis mice

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease associated with CD4+ Th1 and Th17 cell immune responses. Tumour necrosis factor-associated factor 5 (TRAF5) deficiency has been shown to aggravate DSS-induced colitis. However, the potential role of TRAF5 in regulating CD4+ T cell immune responses in the pathogenesis of IBD remains unclear. TRAF5-/- CD4+ CD45RBhigh T cells and WT CD4+ CD45RBhigh T cells were transferred to Rag2-/- mice via intravenous (i.v.) tail injection, respectively, to establish a chronic colitis model. Adeno-associated virus (AAV)-mediated gene knockout technique was used to knock out runt-associated transcription factor 1 (Runx1) expression in vivo. Specific cytokines of Th1 and Th17 cells were detected by quantitative RT-PCR, immunohistochemistry, ELISA, and flow cytometry. In T-cell transfer colitis mice, the Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells showed more severe intestinal inflammation than the WT control group, which was characterised by increased expression of INF-γ, TNF-α, IL-17a. Furthermore, we found that the INF-γ+ CD4+ , IL17a+ CD4+ , and INF-γ+ IL17a+ CD4+ T cells in the intestinal mucosa of Rag2-/- mice reconstituted with TRAF5-/- CD4+ CD45RBhigh T cells were significantly higher than those of the WT control group by flow cytometry. Mechanistically, knockout Runx1 inhibited the differentiation of TRAF5-/- CD4+ T cells into Th1 and Th17 cells in the intestinal mucosa of T-cell transfer colitis mice. TRAF5 regulates Th1 and Th17 cell differentiation and immune response through Runx1 to participate in the pathogenesis of colitis. Thus targeting TRAF5 in CD4+ T cells may be a novel treatment for IBD.

Cepharanthine Exerts Antioxidant and Anti-Inflammatory Effects in Lipopolysaccharide (LPS)-Induced Macrophages and DSS-Induced Colitis Mice

Cepharanthine (CEP), a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata, has been widely used for the treatment of various acute and chronic diseases, including leukopenia, and snake bites. Here, our objective was to investigate the anti-oxidative stress and anti-inflammatory response effects of CEP in lipopolysaccharide (LPS)-induced macrophages as well as dextran sulfate sodium (DSS)-induced colitis mice. Our findings demonstrated that supplementation with CEP effectively mitigates body weight loss and elevation of disease activity index (DAI), reduces the malondialdehyde (MDA) content to 2.45 nM/mL while increasing the reduced glutathione (GSH) content to 35.53 μg/mL, inhibits inflammatory response, and maintains proper intestinal epithelium tight junctions in DSS-induced wild type (WT) mice. However, it failed to provide protective effects in DSS-induced transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) knockout (NRF2-/-) mice. GSH content decreased to 10.85 μg/106 cells following LPS treatment, whereas supplementation with CEP increased the GSH content to 12.26 μg/106 cells. Moreover, CEP effectively attenuated ROS production in LPS-induced macrophages. Additionally, CEP exhibited inhibitory effects on pro-inflammatory cytokines and mediators in LPS-induced macrophages. Furthermore, we observed that supplementation with CEP promoted the expression of NRF2/heme oxygenase 1 (HO-1)/NADPH quinone oxidoreductase-1 (NQO-1) as well as the phosphorylation of the adenosine monophosphate-activated protein kinase alpha 1 (AMPK-α1)/protein kinase B (AKT)/glycogen synthase kinase-3 beta (GSK-3β) signaling pathway in macrophages while inhibiting the phosphorylation of the extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK), and nuclear factor-kappa B p65 (NF-κB p65) signaling pathway in LPS-induced macrophages. Although CEP did not demonstrate inhibitory effects on oxidative stress or promote the expression of HO-1/NQO-1, it effectively activated the phosphorylation of the AMPK-α1/AKT/GSK-3β signaling pathway which is an upstream regulator of NRF2 in LPS-induced primary peritoneal macrophages from NRF2-/- mice. In summary, our findings suggest that CEP exerts protective effects against oxidative stress and inflammatory response by activating the AMPK-α1/AKT/GSK-3β/NRF2 signaling pathway while concurrently inhibiting the activation of mitogen activated protein kinases (MAPKs) and the NF-κB p65 signaling pathway. These results not only elucidate the mechanisms underlying CEP's protective effects on colon oxidative stress and inflammation but also provide evidence supporting NRF2 as a potential therapeutic target for IBD treatment.

Strictosamide alleviates the inflammation in an acute ulcerative colitis (UC) model

The ulcerative colitis (UC) is a typical inflammatory bowel disease (IBD) causing great damages, while strictosamide (STR) is a natural alkaloid that possesses strong anti-inflammatory property in infection and inflammation-related diseases. Our study is aimed at evaluating the anti-inflammatory activity of STR in the course of UC. Briefly, male Balb/c mice were treated with 3.5% dextran sulfate sodium (DSS) for 6 consecutive days to establish an acute model of UC, and the administration of gradient concentrations of STR was subsequently performed. Accordingly, colonic pathological alterations including the reduced ratio of colon weight/length, decreased disease activity index (DAI), and attenuated H&E damage were found in UC mice after STR treatment. Based on the analyses of real-time PCR and western blot, downregulation of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) was also determined in the colonic tissue of UC mice after the treatment of STR. ELISA and immunohistochemical staining further suggest the relief of inflammation in UC mice with decreased expressions of MPO and iNOS after STR treatment. In addition, STR was also validated to significantly inhibit NF-κB signaling in UC mice by western blot and Electrophoretic Mobility Shift Assay (EMSA). Meanwhile, restricted inflammation was also determined in STR-treated IEC6 and HT-29 cells. The utilization of PDTC, an inhibitor of NF-κB, further demonstrated that STR ameliorated the inflammation by inhibiting the NF-κB signaling in vitro. In summary, our study suggests that STR could be a potential candidate for IBD therapy.

Farrerol Ameliorates TNBS-Induced Colonic Inflammation by Inhibiting ERK1/2, JNK1/2, and NF-κB Signaling Pathway

Farrerol, a type of 2, 3-dihydro-flavonoid, is obtained from Rhododendron. Previous studies have shown that Farrerol performs multiple biological activities, such as anti-inflammatory, antibacterial, and antioxidant activity. In this study, we aim to investigate the effect of Farrerol on colonic inflammation and explore its potential mechanisms. We found that the effect of Farrerol was evaluated via the 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model in mice and found that Farrerol has a protective effect on TNBS-induced colitis. Farrerol administration significantly improved the weight change, clinical scores, colon length, and intestinal epithelium barrier damage and markedly decreased the inflammatory cytokines production in TNBS-induced mice. The protective effect of Farrerol was also observed in LPS-induced RAW264.7 cells. We found that Farrerol observably reduced the production of inflammatory mediators including IL-1β, IL-6, TNF-α, COX-2, and iNOS in LPS-induced RAW264.7 cells via suppressing AKT, ERK1/2, JNK1/2, and NF-κB p65 phosphorylation. In conclusion, the study found that Farrerol has a beneficial effect on TNBS-induced colitis and might be a natural therapeutic agent for IBD treatment.

CD82 hypomethylation is essential for tuberculosis pathogenesis via regulation of RUNX1-Rab5/22

The tumor suppressor gene CD82/KAI1 is a member of the tetraspanin superfamily and organizes various membrane-based processes. Mycobacterium tuberculosis (MTB) persists in host macrophages by interfering with phagolysosome biogenesis and inflammatory responses, but the role of CD82 in controlling the intracellular survival of pathogenic mycobacteria within macrophages remains poorly understood. In this study, we demonstrated that the virulent MTB strain H37Rv (MTB Rv) induced CD82 promoter hypomethylation, resulting in CD82 expression. Targeting of the runt-related transcription factor 1 (RUNX1) by CD82 is essential for phagosome arrest via interacting with Rab5/22. This arrest is required for the intracellular growth of MTB in vitro and in vivo, but not for that of MTB H37Ra (MTB Ra) in macrophages. In addition, knockdown or knockout of CD82 or RUNX1 increased antibacterial host defense via phagolysosome biogenesis, inflammatory cytokine production, and subsequent antimicrobial activity both in vitro and in vivo. Notably, the levels of CD82 and RUNX1 in granulomas were elevated in tuberculosis (TB) patients, indicating that CD82 and RUNX1 have clinical significance in human TB. Our findings identify a previously unrecognized role of CD82 hypomethylation in the regulation of phagosome maturation, enhanced intracellular survival, and the innate host immune response to MTB. Thus, the CD82-RUNX1-Rab5/22 axis may be a previously unrecognized virulence mechanism of MTB pathogenesis.

Sodium Butyrate Inhibits Inflammation and Maintains Epithelium Barrier Integrity in a TNBS-induced Inflammatory Bowel Disease Mice Model

G Protein Coupled Receptor 109A (GPR109A), which belongs to the G protein coupled receptor family, can be activated by niacin, butyrate, and β-hydroxybutyric acid. Here, we assessed the anti-inflammatory activity of sodium butyrate (SB) on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis mice, an experimental model that resembles Crohn's disease, and explored the potential mechanism of SB in inflammatory bowel disease (IBD). In vivo, experimental GPR109a^-/- and wild-type (WT) mice were administered SB (5g/L) in their drinking water for 6weeks. The mice were then administered TNBS via rectal perfusion to imitate colitis. In vitro, RAW246.7 macrophages, Caco-2 cells, and primary peritoneal macrophages were used to investigate the protective roles of SB on lipopolysaccharide (LPS)-induced inflammatory response and epithelium barrier dysfunction. In vivo, SB significantly ameliorated the inflammatory response and intestinal epithelium barrier dysfunction in TNBS-induced WT mice, but failed to provide a protective effect in TNBS-induced GPR109a^-/- mice. In vitro, pre-treatment with SB dramatically inhibited the expression of TNF-α and IL-6 in LPS-induced RAW246.7 macrophages. SB inhibited the LPS-induced phosphorylation of the NF-κB p65 and AKT signaling pathways, but failed to inhibit the phosphorylation of the MAPK signaling pathway. Our data indicated that SB ameliorated the TNBS-induced inflammatory response and intestinal epithelium barrier dysfunction through activating GPR109A and inhibiting the AKT and NF-κB p65 signaling pathways. These findings therefore extend the understanding of GPR109A receptor function and provide a new theoretical basis for treatment of IBD.

Critical Evaluation of Animal Models of Gastrointestinal Disorders

Preclinical research remains an important tool for discovery and validation of novel therapeutics for gastrointestinal disorders. While in vitro assays can be used to verify receptor-ligand interactions and test for structural activity of new compounds, only whole-animal studies can demonstrate drug efficacy within the gastrointestinal system. Most major gastrointestinal disorders have been modeled in animals; however the translational relevance of each model is not equal. The purpose of this chapter is to provide a critical evaluation of common animal models that are being used to develop pharmaceuticals for gastrointestinal disorders. For brevity, the models are presented for upper gastrointestinal disorders involving the esophagus, stomach, and small intestine and lower gastrointestinal disorders that focus on the colon. Particular emphasis is used to explain the face and construct validity of each model, and the limitations of each model, including data interpretation, are highlighted. This chapter does not evaluate models that rely on surgical or other non-pharmacological interventions for treatment.

VGLUTs and Glutamate Synthesis-Focus on DRG Neurons and Pain

The amino acid glutamate is the principal excitatory transmitter in the nervous system, including in sensory neurons that convey pain sensation from the periphery to the brain. It is now well established that a family of membrane proteins, termed vesicular glutamate transporters (VGLUTs), serve a critical function in these neurons: they incorporate glutamate into synaptic vesicles. VGLUTs have a central role both under normal neurotransmission and pathological conditions, such as neuropathic or inflammatory pain. In the present short review, we will address VGLUTs in the context of primary afferent neurons. We will focus on the role of VGLUTs in pain triggered by noxious stimuli, peripheral nerve injury, and tissue inflammation, as mostly explored in transgenic mice. The possible interplay between glutamate biosynthesis and VGLUT-dependent packaging in synaptic vesicles, and its potential impact in various pain states will be presented.

Animal models of gastrointestinal and liver diseases. Animal models of visceral pain: pathophysiology, translational relevance, and challenges

Visceral pain describes pain emanating from the thoracic, pelvic, or abdominal organs. In contrast to somatic pain, visceral pain is generally vague, poorly localized, and characterized by hypersensitivity to a stimulus such as organ distension. Animal models have played a pivotal role in our understanding of the mechanisms underlying the pathophysiology of visceral pain. This review focuses on animal models of visceral pain and their translational relevance. In addition, the challenges of using animal models to develop novel therapeutic approaches to treat visceral pain will be discussed.

Cognitive deficits in pediatric-onset multiple sclerosis: what does the future hold?

Pediatric-onset multiple sclerosis is relatively rare and research regarding disease characteristics is in its infancy. Regardless, there are a growing number of studies finding early cognitive deficits in this population. There are some similarities in outcomes to those seen in the adult-onset multiple sclerosis population, but also several important differences. With specific regard to cognitive functioning in pediatric-onset multiple sclerosis, there is evidence of deficit in nearly a third of patients, with impairment primarily in areas of processing speed, visual-spatial processing and language. There are additional findings of fatigue and depression that impact functional outcomes requiring further attention in assessment and treatment considerations. This paper also explores other areas requiring increased focus, including treatment and outcomes, neuroimaging and additional disease-modifying factors (comorbidities, socioeconomic status, race and so on).

Increasing substance P levels in serum and synovial tissues from patients with developmental dysplasia of the hip (DDH)

BACKGROUND

The tachykininergic neurotransmitters have been proved to be involved in the inflammatory progress and chronic pain in series of disease. The present study was undertaken to evaluate the levels of substance P (SP) and its receptors NK-1 receptor (NK-1R) in both serum and synovial tissues of hip joint from patients with different stages of DDH, and to detect the possible correlation of serum SP levels with pain sensation and dysfunction of the hip joint.

METHODS

SP levels in serum and synovial tissues from patients with DDH and DDH combined with osteoarthritis (DDH&OA) group were compared through immunohistochemistry (IHC), ELISA, and 2-step acetic acid extraction method respectively. Expression of NK-1R in synovial tissues was compared through IHC, quantitive Real-Time PCR (QRT-PCR) and Western-Blot. The severities of pain sensation and the functional activities of hip joint were assessed by Visual analogue scale (VAS) and Harris hip score (HHS). Correlations of serum SP levels with VAS, HHS and erythrocyte sedimentation rate (ESR) were evaluated respectively in these groups.

RESULTS

Significantly elevated serum SP levels were detected in group of DDH and DDH&OA compared to that in normal group. IHC, QRT-PCR as well as tissue Elisa showed that SP levels in synovial tissue of DDH&OA group is stronger than that in DDH group. Serum SP levels in each group have no gender differences. The enhanced SP levels in synovial tissue mainly came from the segregation of peripheral nerve endings. Serum SP correlated with VAS and HHS in patients with DDH&OA (Male + Female). Serum SP correlated with HHS in patients with DDH (Male). Serum SP levels also correlated with erythrocyte sedimentation rate (ESR) in patients with DDH&OA (Male + Female). Up-regulated expression of NK-1R was also observed in synovial tissue of patients with DDH&OA compared to patients with DDH, through western-blot, IHC, and QRT-PCR.

CONCLUSIONS

These findings indicated that the increasing SP levels in serum and synovial tissues, observed from patients with DDH to patients with DDH&OA, might associate with the loss of function and chronic pain sensation in hip joint. SP along with its receptors NK-1R might be involved in the progression of DDH into DDH&OA. In the future, inhibitors of SP as well as NK-1R may represent a novel pharmacotherapy target for pain relieving, inflammation alleviating and joint degeneration delaying for patients with DDH.