Project description:Sepsis-associated acute kidney injury (SA-AKI) is a common clinical critical care syndrome. It has received increasing attention due to its high morbidity and mortality; however, its pathophysiological mechanisms remain elusive. LIGHT, the 14th member of the tumour necrosis factor (TNF) superfamily and a bidirectional immunoregulatory molecule that regulates inflammation, plays a pivotal role in disease pathogenesis. In this study, mice with an intraperitoneal injection of LPS and HK-2 cells challenged with LPS were employed as a model of SA-AKI in vivo and in vitro, respectively. LIGHT deficiency notably attenuated kidney injury in pathological damage and renal function and markedly mitigated the inflammatory reaction by decreasing inflammatory mediator production and inflammatory cell infiltration in vivo. The TLR4-Myd88-NF-κB signalling pathway in the kidney of LIGHT knockout mice was dramatically down-regulated compared to the controls. Recombinant human LIGHT aggravated LPS-treated HK-2 cell injury by up-regulating the expression of the TLR4-Myd88-NF-κB signalling pathway and inflammation levels. TAK 242 (a selective TLR4 inhibitor) reduced this trend to some extent. In addition, blocking LIGHT with soluble receptor fusion proteins HVEM-Fc or LTβR-Fc in mice attenuated renal dysfunction and pathological damage in SA-AKI. Our findings indicate that LIGHT aggravates inflammation and promotes kidney damage in LPS-induced SA-AKI via the TLR4-Myd88-NF-κB signalling pathway, which provide potential strategies for the treatment of SA-AKI.
Project description:In this study, we aim to investigate the role of tanshinone IIA in myocardial infarction (MI), especially in left ventricular remodelling (VR) and the underlying mechanism involving the TLR4/MyD88/NF-κB signalling pathway. Sprague-Dawley (SD) rats (n = 96) were selected, and 12 of them underwent sham surgery. The remaining 84 rats were subjected to MI modelling. HE and MT staining were carried out to estimate infract size, histopathological changes and fibrosis degree. Macrophage infiltration and cardiomyocyte apoptosis were evaluated by immunohistochemistry and TUNEL staining. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to determine the expression levels of TLR4, MyD88 and NF-κB. Serum levels of IL-2, IL-6, IL-8, TNF-a, procollagen I Cpropeptide (PICP), and procollagen III N-propeptide (PIIINP) were measured using enzyme-linked immunosorbent assay (ELISA). The heart weight/body weight, mean arterial pressure (MAP), left ventricular end-systolic pressure (LVESP), +dP/dt and -dP/dt increased while the ventricular function and the left ventricular end-diastole pressure (LVEDP) decreased in MI rats. Compared with the rats undergoing sham surgery, MI rats showed larger infarct size, severer fibrosis, higher expression levels of TLR4, NF-κB-P65, MyD88, IL-2, IL-6, IL-8, TNF-a, PICP and PIIINP as well as enhanced macrophage infiltration, cardiomyocyte apoptosis. After treatment with tanshinone IIA combined with LPS for 4 weeks, the rats showed better condition than those treated with only LPS. These results indicate that tanshinone IIA attenuates MI and prevents left VR. Importantly, inhibition of TLR4/MyD88/NF-κB signalling pathway is a key step in this process.
Project description:This study was conducted to identify whether the TLR4/MyD88/NF-κB signalling pathway plays a vital role in osteoarthritis (OA) treatment with Duhuo Jisheng Decoction (DHJSD) on the basis of a network pharmacology approach (NPA)-integrated experiment. Two experiments were conducted as follow: NPA for DHJSD using six OA-related gene series and the key pathway was screened out using NPA. NPA identified a vital role for the TLR4/MyD88/NF-κB signalling pathway in OA treatment with DHJSD, the conventional western blot analysis and qPCR confirmed it. Furthermore, changes of miR-146a-5p and miR-34a-5p in the cellular models were recovered by DHJSD administration, which synergistically contributed to OA therapy. The toll-like receptor signalling pathway and the NF-κB signalling pathway were meaningfully enriched by the miRNA-regulated gene pathways. This study identified and confirmed the TLR4/MyD88/NF-κB signalling pathway is an essential inflammatory signalling pathway in the DHJSD underlying OA treatment. The results provide a basis for further evaluation of the regulatory mechanism of the drug's efficacy in treating OA.
Project description:BackgroundJianpi Yangxue Qufeng Compound (JPYXQFC) is a Chinese medicine widely used in the clinical treatment of atopic dermatitis (AD) and has a significantly therapeutic effect. However, the mechanism of JPYXQFC in AD has been not understood clearly.ObjectiveThis study aimed to explore the effect of JPYXQFC on AD model cells and rats by regulating TLR4/MyD88/NF-κB signaling pathway.MethodsThe rats (n > 5) were given JPYXQFC decoction orally twice a day for three days, and their abdominal aortic blood was collected. HaCaT cell proliferation rate was tested by cell counting kit-8 (CCK-8) assays. We induced AD rat model through 2, 4-dinitrofluorobenzene (DNFB). AD rats were given oral JPYXQFC decoction and cetirizine (positive control). HaCaT cells were pretreated with JPYXQFC drug serum or cetirizine for 0.5 h and then stimulated with TNF-α/IFN-γ for 1 h. The mRNA levels of TLR4, MyD88, NF-κB, IL-4, IL-13, MCP1, TNF-α and TSLP were detected by quantitative real-time PCR (Q-RT-PCR), and TLR4/MyD88/NF-κB pathway protein expression was tested by Western blot. The total serum levels of immunoglobulin E (IgE), thymus and activation regulated chemokine/chemokine (C-C motif) ligand 17 (TARC/CCL17) were detected by enzyme-linked immunosorbent assay (ELISA). The epidermal thickness was detected by hematoxylin and eosin (HE) staining. The dermatitis area and score were measured by a ruler and a four-point scoring method, respectively.ResultsJPYXQFC significantly inhibited mRNA and protein expression of the TLR4/MyD88/NF-κB pathway and Histone H3 in TNF-α/IFN-γ-induced HaCaT cells and DNFB-induced rats, decreased the mRNA of IL-4, IL-13, MCP1, CCL22, TSLP and the level of AD-related genes IgE and TAEC/CCL17 of TNF-α/IFN-γ-induced HaCaT cells. Meanwhile, JPYXQFC significantly reduced the dermatitis area and dermatitis score in DNFB-induced rats, inhibited the levels of pro-inflammatory cytokines IL-6 and TNF-α, and upregulated FLG, as well as inhibited the levels of IgE and TARC/CCL17 in the serum of AD rats.ConclusionJPYXQFC alleviates AD by inhibiting the activation of TLR4/MyD88/NF-κB pathway.
Project description:Background and aimsDefective autophagy has been proposed as an important event in a growing number of autoimmune and inflammatory diseases such as rheumatoid arthritis and lupus. However, the precise role of mechanistic target of rapamycin (mTOR)-dependent autophagy and its underlying regulatory mechanisms in the intestinal epithelium in response to inflammation and oxidative stress remain poorly understood.MethodsThe levels of p-mTOR, LC3B, p62 and autophagy in mice and LPS-treated cells were examined by immunoblotting, immunohistochemistry, confocal microscopy and transmission electron microscopy (TEM). We evaluated the expression of IL-1β, IL-8, TNF-α, MDA, SOD and T-AOC by quantitative real time-polymerase chain reaction (qRT-PCR) and commercially available kits after silencing of mTOR and ATG5. In vivo modulation of mTOR and autophagy was achieved by using AZD8055, rapamycin and 3-methyladenine. Finally, to verify the involvement of TLR4 signalling and the NF-κB pathway in cells and active ulcerative colitis (UC) patients, immunofluorescence, qRT-PCR, immunoblotting and TEM were performed to determine TLR4 signalling relevance to autophagy and inflammation.ResultsThe mTOR-dependent autophagic flux impairment in a murine model of colitis, human intestinal epithelial cells and active UC patients is probably regulated by TLR4-MyD88-MAPK signalling and the NF-κB pathway. Silencing mTOR remarkably attenuated, whereas inhibiting ATG5 aggravated, LPS-induced inflammation and oxidative injury. Pharmacological administration of mTOR inhibitors and autophagy stimulators markedly ameliorated experimental colitis and oxidative stress in vivo.ConclusionsOur findings not only shed light on the regulatory mechanism of mTOR-dependent autophagy, but also provided potential therapeutic targets for intestinal inflammatory diseases such as refractory inflammatory bowel disease.
Project description:Background and purposeStudies have demonstrated that a moderate intake of amino acids is associated with development of bone health. Methionine, a sulphur-containing essential amino acid, has been largely implicated for improving cartilage formation, however its physiological significance on bone integrity and functionality have not been elucidated. We investigated whether methionine can prevent osteoporotic bone loss.Experimental approachThe anti-resorptive effect of methionine, (250 mg kg(-1) body wt administered in drinking water for 10 weeks), was evaluated in ovariectomized (OVX) rats by monitoring changes in bone turnover, formation of osteoclasts from blood-derived mononuclear cells and changes in the synthesis of pro-osteoclastogenic cytokines.Key resultsMethionine improved bone density and significantly decreased the degree of osteoclast development from blood mononuclear cells in OVX rats, as indicated by decreased production of osteoclast markers tartarate resistant acid phosphatase b (TRAP5b) and MIP-1α. siRNA-mediated knockdown of myeloid differentiation primary response 88 [MyD88], a signalling molecule in the toll-like receptor (TLR) signalling cascade, abolished the synthesis of both TRAP5b and MIP-1α in developing osteoclasts. Methionine supplementation disrupted osteoclast development by inhibiting TLR-4/MyD88/NF-κB pathway.Conclusions and implicationsTLR-4/MyD88/NF-κB signalling pathway is integral for osteoclast development and this is down-regulated in osteoporotic system on methionine treatment. Methionine treatment could be beneficial for the treatment of postmenopausal osteoporosis.
Project description:Introduction: Gouty nephropathy (GN) arises from factors like excessive purine intake, metabolic disorders or abnormal synthesis, and uric acid hypersaturation in the blood, leading to urate crystal deposition in kidney tissue. DaiTongXiao (DTX) is a remedy used by the Dai people of China. It shows efficacy in lowering uric acid levels and exhibits anti-inflammatory and kidney-protective properties. Methods: A GN rat model was induced using adenine and potassium oxonate. Following DTX administration, various parameters were assessed in urine, serum, and kidney tissue. Western blot analysis evaluated TLR4/MyD88/NF-κB signaling proteins, while immunofluorescence examined NF-κB nuclear expression. Results: DTX treatment improved kidney morphology, increased body weight, and kidney index and enhanced urinary levels of blood urea nitrogen (Bun), 24-h urinary protein, uric acid (UA), and allantoin in GN rats, reducing UA, Bun, creatinine (Cre), cystatin C (CysC), serum amyloid A (SAA), α1-microglobulin (MG), and β2-MG in serum analysis. Renal tissue assessments showed decreased xanthine oxidase (XOD), hydroxyproline (Hyp), α-smooth muscle actin (α-SMA), and collage type Ⅳ (COL-Ⅳ). Kidney damage severity was notably reduced. DTX lowered serum inflammatory factors like interleukin (IL) -18, tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), transforming growth factor-β1 (TGF-β1), and IL-1β in the rat serum, reducing chemokine monocyte chemoattractant protein-1 (MCP-1) and adhesion factor vascular cell adhesion molecule-1(VCAM-1). Western blotting demonstrated the downregulation of TLR4/MyD88/NF-κB pathway proteins, and immunofluorescence revealed reduced NF-κB expression in renal tissue. Discussion: DTX exhibits significant anti-GN effects by modulating TLR4/MyD88/ NF-κB pathway protein expression, reducing inflammatory factor release, and inhibiting GN progression.
Project description:Inflammatory bowel disease (namely, colitis) severely impairs human health. Isoleucine is reported to regulate immune function (such as the production of immunoreactive substances). The aim of this study was to investigate whether l-isoleucine administration might alleviate dextran sulfate sodium (DSS)-induced colitis in rats. In the in vitro trial, IEC-18 cells were treated by 4 mmol/L l-isoleucine for 12 h, which relieved the decrease of cell viability that was induced by TNF-α (10 ng/ml) challenge for 24 h (P <0.05). Then, in the in vivo experiment, a total of 44 Wistar rats were allotted into 2 groups that were fed l-isoleucine-supplemented diet and control diet for 35 d. From 15 to 35 d, half of the rats in the 2 groups drank the 4% DSS-adding water. Average daily gain, average daily feed intake and feed conversion of rats were impaired by DSS challenge (P <0.05). Drinking the DSS-supplementing water also increased disease activity index (DAI) and serum urea nitrogen level (P <0.05), shortened colonic length (P <0.05), impaired colonic enterocyte apoptosis, cell cycle, and the ZO-1 mRNA expression (P <0.05), increased the ratio of CD11c-, CD64-, and CD169-positive cells in colon (P <0.05), and induced extensive ulcer, infiltration of inflammatory cells, and collagenous fiber hyperplasia in colon. However, dietary l-isoleucine supplementation attenuated the negative effect of DSS challenge on growth performance (P <0.05), DAI (P <0.05), colonic length and enterocyte apoptosis (P <0.05), and dysfunction of colonic histology, and downregulated the ratio of CD11c-, CD64-, and CD169-positive cells, pro-inflammation cytokines and the mRNA expression of TLR4, MyD88, and NF-κB in the colon of rats (P <0.05). These results suggest that supplementing l-isoleucine in diet improved the DSS-induced growth stunting and colonic damage in rats, which could be associated with the downregulation of inflammation via regulating TLR4/MyD88/NF-κB pathway in colon.
Project description:Neuroinflammation is a major feature of type 2 diabetic mellitus (T2DM), adversely affecting hippocampal neurogenesis. However, the precise mechanism is not fully understood, and therapeutic approaches are currently lacking. Therefore, we determined the effects of exercise on neuroinflammation and hippocampal neurogenesis in T2DM mice, with a specific focus on understanding the role of the irisin and related cascade pathways in modulating the beneficial effects of exercise in these processes. Ten-week exercise significantly decreased T2DM-induced inflammation levels and markedly promoted hippocampal neurogenesis and memory function. However, these positive effects were reversed by 10 weeks of treatment with cyclo RGDyk, an inhibitor of irisin receptor signaling. Additionally, exercise helped reduce the M1 phenotype polarization of hippocampal microglia in diabetic mice; this effect could be reversed with cyclo RGDyk treatment. Moreover, exercise markedly increased the levels of fibronectin type III domain-containing protein 5 (FNDC5)/irisin protein while decreasing the expression of Toll-like receptor 4 (TLR4), myeloid differential protein-88 (MyD88), and nuclear factor kappa-B (NF-κB) in the hippocampus of T2DM mice. However, blocking irisin receptor signaling counteracted the down-regulation of TLR4/MyD88/NF-κB in diabetic mice undergoing exercise intervention. Conclusively, exercise appears to be effective in reducing neuroinflammation and enhancing hippocampal neurogenesis and memory in diabetes mice. The positive effects are involved in the participation of the irisin/TLR4/MyD88/NF-κB signaling pathway, highlighting the potential of exercise in the management of diabetic-induced cognitive decline.