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In this editorial, we comment on the article by Wu et al published "MicroRNA-630 alleviates inflammatory reactions in rats with diabetic kidney disease by targeting toll-like receptor 4". Diabetic kidney disease (DKD) stands as a significant complication occurring from diabetes mellitus, which contributes substantially to the morbidity and mortality rates worldwide. Renal tubular epithelial cell da-mage, often accompanied by inflammatory responses and mesenchymal trans-differentiation, plays a pivotal role in the progression of DKD. Despite extensive research, the intricate molecular mechanisms underlying these processes remain to be determined. Wu et al remarkable work identifies microRNA-630 (miR-630) as an emerging potential regulator of cell migration, apoptosis, and autophagy, prompting investigation into its association with DKD pathogenesis. This study endeavors to elucidate the impact of miR-630 on TEC injury and the inflammatory response in DKD rats. The role of miR-630 in human DKD will be of interest for future studies.
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Mammalian milk exosomal miRNAs play an important role in maintaining intestinal immune homeostasis and protecting epithelial barrier function, but the specific miRNAs and whether miRNA-mediated mechanisms are responsible for these benefits remain a matter of investigation. This study isolated sheep milk-derived exosomes (sheep MDEs), identifying the enriched miRNAs in sheep MDEs, oar-miR-148a, and oar-let-7b as key components targeting TLR4 and TRAF1, which was validated by a dual-luciferase reporter assay. In dextran sulfate sodium-induced colitis mice, administration of sheep MDEs alleviated colitis symptoms, reduced colonic inflammation, and systemic oxidative stress, as well as significantly increased colonic oar-miR-148a and oar-let-7b while reducing toll-like receptor 4 (TLR4) and TNF-receptor-associated factor 1 (TRAF1) level. Further characterization in TNF-α-challenged Caco-2 cells showed that overexpression of these miRNAs suppressed the TLR4/TRAF1-IκBα-p65 pathway and reduced IL-6 and IL-12 production. These findings indicate that sheep MDEs exert gastrointestinal anti-inflammatory effects through the miRNA-mediated modulation of TLR4 and TRAF1, highlighting their potential in managing colitis.
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The excessive inflammation caused by the prolonged activation of Toll-like receptor 4 (TLR4) and its downstream signaling pathways leads to sepsis. CD14-mediated endocytosis of TLR4 is the key step to control the amount of TLR4 on cell membrane and the activity of downstream pathways. The actin cytoskeleton is necessary for receptor-mediated endocytosis, but its role in TLR4 endocytosis remains elusive. Here we show that Tropomodulin 1 (Tmod1), an actin capping protein, inhibited lipopolysaccharide (LPS)-induced TLR4 endocytosis and intracellular trafficking in macrophages. Thus it resulted in increased surface TLR4 and the upregulation of myeloid differentiation factor 88 (MyD88)-dependent pathway and the downregulation of TIR domain-containing adaptor-inducing interferon-ß (TRIF)-dependent pathway, leading to the enhanced secretion of inflammatory cytokines, such as TNF-α and IL-6, and the reduced secretion of cytokines, such as IFN-ß. Macrophages deficient with Tmod1 relieved the inflammatory response in LPS-induced acute lung injury mouse model. Mechanistically, Tmod1 negatively regulated LPS-induced TLR4 endocytosis and inflammatory response through modulating the activity of CD14/Syk/PLCγ2/IP3/Ca2+ signaling pathway, the reorganization of actin cytoskeleton, and the membrane tension. Therefore, Tmod1 is a key regulator of inflammatory response and immune functions in macrophages and may be a potential target for the treatment of excessive inflammation and sepsis.
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Endocitosis , Inflamación , Lipopolisacáridos , Macrófagos , Ratones Endogámicos C57BL , Transducción de Señal , Receptor Toll-Like 4 , Tropomodulina , Animales , Receptor Toll-Like 4/metabolismo , Lipopolisacáridos/farmacología , Ratones , Macrófagos/metabolismo , Macrófagos/inmunología , Inflamación/metabolismo , Inflamación/patología , Tropomodulina/metabolismo , Tropomodulina/genética , Citocinas/metabolismo , Células RAW 264.7 , Factor 88 de Diferenciación Mieloide/metabolismo , Factor 88 de Diferenciación Mieloide/genética , Receptores de Lipopolisacáridos/metabolismo , Masculino , Ratones Noqueados , Citoesqueleto de Actina/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/genética , Lesión Pulmonar Aguda/metabolismo , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/patologíaRESUMEN
Diabetic nephropathy (DN), a severe complication of diabetes, is widely recognized as a primary contributor to end-stage renal disease. Recent studies indicate that the inflammation triggered by Toll-like receptor 4 (TLR4) is of paramount importance in the onset and progression of DN. TLR4 can bind to various ligands, including exogenous ligands such as proteins and polysaccharides from bacteria or viruses, as well as endogenous ligands such as biglycan, fibrinogen, and hyaluronan. In DN, the expression or release of TLR4-related ligands is significantly elevated, resulting in excessive TLR4 activation and increased production of proinflammatory cytokines through downstream signaling pathways. This process is closely associated with the progression of DN. Natural compounds are biologically active products derived from natural sources that have advantages in the treatment of certain diseases. Various types of natural compounds, including alkaloids, flavonoids, polyphenols, terpenoids, glycosides, and polysaccharides, have demonstrated their ability to improve DN by affecting the TLR4 signaling pathway. In this review, we summarize the mechanism of action of TLR4 in DN and the natural compounds that can ameliorate DN by modulating the TLR4 signaling pathway. We specifically highlight the potential of compounds such as curcumin, paclitaxel, berberine, and ursolic acid to inhibit the TLR4 signaling pathway, which provides an important direction of research for the treatment of DN.
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Obesity is characterized by the chronic low-grade activation of the innate immune system. In this respect, macrophage-elicited metabolic inflammation and adipocyte-macrophage interaction have primary importance in obesity. Large quantity of macrophages is accumulated by different mechanisms in obese adipose tissue. Hypertrophic adipocyte-derived chemotactic monocyte chemoattractant protein-1 (MCP-1)/C-C chemokine receptor 2 (CCR2) pathway promotes more macrophage accumulation into the obese adipose tissue. However, obesity-induced changes in adipose tissue macrophage density are mainly dependent on increases in the triple-positive cluster of differentiation (CD)11b+ F4/80+ CD11c+ adipose tissue macrophage subpopulation. As epigenetic regulators, microRNAs (miRNAs) are one of the most important mediators of obesity. miRNAs are expressed by adipocytes as well as macrophages and regulate inflammation with the expression of target genes. A paracrine loop involving free fatty acids and tumor necrosis factor-alpha (TNF-α) between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes in the adipose tissue. Adipocyte-specific caspase-1 and production of interleukin-1beta (IL-1ß) by macrophages; both adipocyte and macrophage induction by toll-like receptor-4 (TLR4) through nuclear factor-kappaB (NF-κB) activation; free fatty acid-induced and TLR-mediated activation of c-Jun N-terminal kinase (JNK)-related pro-inflammatory pathways in CD11c+ immune cells; are effective in mutual message transmission between adipocyte and macrophage and in the development of adipose tissue inflammation. Thus, the metabolic status of adipocytes and their released exosomes are important determinants of macrophage inflammatory output. However, old adipocytes are removed by macrophages through trogocytosis or sending an "eat me" signal. As a single miRNA can be able to regulate a variety of target genes and signaling pathways, reciprocal transfer of miRNAs between adipocytes and macrophages via miRNA-loaded exosomes reorganizes the different stages of obesity. Changes in the expression of circulating miRNAs because of obesity progression or anti-obesity treatment indicate that miRNAs could be used as potential biomarkers. Therefore, it is believed that targeting macrophage-associated miRNAs with anti-obesity miRNA-loaded nano-carriers may be successful in the attenuation of both obesity and adipose tissue inflammation in clinical practice. Moreover, miRNA-containing exosomes and transferable mitochondria between the adipocyte and macrophage are investigated as new therapeutic targets for obesity-related metabolic disorders.
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Adipocitos , Macrófagos , Obesidad , Obesidad/metabolismo , Obesidad/genética , Humanos , Macrófagos/metabolismo , Macrófagos/inmunología , Adipocitos/metabolismo , Animales , MicroARNs/genética , MicroARNs/metabolismo , Transducción de Señal , Tejido Adiposo/metabolismo , Inflamación/metabolismo , Inflamación/patología , Comunicación CelularRESUMEN
Chronic low-grade inflammation is a central component in the pathogenesis of obesity-related expansion of adipose tissue and complications in other metabolic tissues. Five different signaling pathways are defined as dominant determinants of adipose tissue inflammation: These are increased circulating endotoxin due to dysregulation in the microbiota-gut-brain axis, systemic oxidative stress, macrophage accumulation, and adipocyte death. Finally, the nucleotide-binding and oligomerization domain (NOD) leucine-rich repeat family pyrin domain-containing 3 (NLRP3) inflammasome pathway is noted to be a key regulator of metabolic inflammation. The NLRP3 inflammasome and associated metabolic inflammation play an important role in the relationships among fatty acids and obesity. Several highly active molecules, including primarily leptin, resistin, adiponectin, visfatin, and classical cytokines, are abundantly released from adipocytes. The most important cytokines that are released by inflammatory cells infiltrating obese adipose tissue are tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) (CCL-2), and IL-1. All these molecules mentioned above act on immune cells, causing local and then general inflammation. Three metabolic pathways are noteworthy in the development of adipose tissue inflammation: toll-like receptor 4 (TLR4)/phosphatidylinositol-3'-kinase (PI3K)/Protein kinase B (Akt) signaling pathway, endoplasmic reticulum (ER) stress-derived unfolded protein response (UPR), and inhibitor of nuclear factor kappa-B kinase beta (IKKß)-nuclear factor kappa B (NF-κB) pathway. In fact, adipose tissue inflammation is an adaptive response that contributes to a visceral depot barrier that effectively filters gut-derived endotoxin. Excessive fatty acid release worsens adipose tissue inflammation and contributes to insulin resistance. However, suppression of adipose inflammation in obesity with anti-inflammatory drugs is not a rational solution and paradoxically promotes insulin resistance, despite beneficial effects on weight gain. Inflammatory pathways in adipocytes are indeed indispensable for maintaining systemic insulin sensitivity. Cannabinoid type 1 receptor (CB1R) is important in obesity-induced pro-inflammatory response; however, blockade of CB1R, contrary to anti-inflammatory drugs, breaks the links between insulin resistance and adipose tissue inflammation. Obesity, however, could be decreased by improving leptin signaling, white adipose tissue browning, gut microbiota interactions, and alleviating inflammation. Furthermore, capsaicin synthesized by chilies is thought to be a new and promising therapeutic option in obesity, as it prevents metabolic endotoxemia and systemic chronic low-grade inflammation caused by high-fat diet.
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Tejido Adiposo , Inflamación , Obesidad , Transducción de Señal , Humanos , Obesidad/metabolismo , Obesidad/inmunología , Obesidad/patología , Tejido Adiposo/metabolismo , Tejido Adiposo/inmunología , Tejido Adiposo/patología , Animales , Inflamación/metabolismo , Inflamación/patología , Citocinas/metabolismo , Inflamasomas/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Mediadores de Inflamación/metabolismoRESUMEN
In obesity, the process of adipogenesis largely determines the number of adipocytes in body fat depots. Adipogenesis is regulated by several adipocyte-selective micro-ribonucleic acids (miRNAs) and transcription factors that modulate adipocyte proliferation and differentiation. However, some miRNAs block the expression of master regulators of adipogenesis. Since the specific miRNAs display different expressions during adipogenesis, in mature adipocytes and permanent obesity, their use as biomarkers or therapeutic targets is feasible. Upregulated miRNAs in persistent obesity are downregulated during adipogenesis. Moreover, some of the downregulated miRNAs in obese individuals are upregulated in mature adipocytes. Induction of adipocyte stress and hypertrophy leads to the release of adipocyte-derived exosomes (AdEXs) that contain the cargo molecules, miRNAs. miRNAs are important messengers for intercellular communication involved in metabolic responses and have very specific signatures that direct the metabolic activity of target cells. While each miRNA targets multiple messenger RNAs (mRNAs), which may coordinate or antagonize each other's functions, several miRNAs are dysregulated in other tissues during obesity-related comorbidities. Deletion of the miRNA-processing enzyme DICER in pro-opiomelanocortin-expressing cells results in obesity, which is characterized by hyperphagia, increased adiposity, hyperleptinemia, defective glucose metabolism, and alterations in the pituitary-adrenal axis. In recent years, RNA-based therapeutical approaches have entered clinical trials as novel therapies against overweight and its complications. Development of lipid droplets, macrophage accumulation, macrophage polarization, tumor necrosis factor receptor-associated factor 6 activity, lipolysis, lipotoxicity, and insulin resistance are effectively controlled by miRNAs. Thereby, miRNAs as epigenetic regulators are used to determine the new gene transcripts and therapeutic targets.
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Adipogénesis , Epigénesis Genética , MicroARNs , Obesidad , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Obesidad/genética , Obesidad/metabolismo , Adipogénesis/genética , Animales , Adipocitos/metabolismo , Exosomas/metabolismo , Exosomas/genética , Regulación de la Expresión GénicaRESUMEN
Several investigations have been carried out to explore the genetic association of TLR4 codon variants, specifically Asp299Gly and Thr399Ile, and susceptibility to sepsis, but the results have been contradictory. The present study aimed to conduct a meta-analysis to draw a definitive conclusion regarding the role of TLR4 genetic variants (Asp299Gly and Thr399Ile) in sepsis. A thorough literature search was conducted using the PubMed, Scopus, and Science Direct databases. The inclusion and exclusion criteria were established to ensure the accuracy of the data. The Comprehensive Meta-Analysis Software v4 was utilized to perform the meta-analysis and related analyses. A total of 13 studies were analyzed, including 2328 sepsis cases and 2495 healthy controls for the TLR4 Asp299Gly variant. Eight studies provided genotype data for the rs4986791 polymorphism. The Asp299Gly variant showed a marginal protective effect in the allele (p = 0.08, odds ratio = 0.71) and dominant (p = 0.09, odds ratio = 0.71) genetic models, although it was not statistically significant. The trial sequential analysis indicated that further case-control studies are necessary to draw definitive conclusions about the TLR4 polymorphisms in sepsis. The TLR4 Asp299Gly variant may have a protective effect against sepsis. However, additional research with larger sample sizes across diverse populations is required to validate this finding.
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Long-term inflammation can cause chronic pain and trigger patients' anxiety by sensitizing the central nervous system. However, effective drugs with few side effects for treating chronic pain-induced anxiety are still lacking. The anxiolytic and anti-inflammatory effects of ruscogenin (RUS), an important active compound in Ophiopogon japonicus, were evaluated in a mouse model of chronic inflammatory pain and N9 cells. RUS (5, 10, or 20 mg/kg/day, i.g.) was administered once daily for 7 days after CFA injection; pain- and anxiety-like behaviors were assessed in mice. Anti-inflammatory effect of RUS (0.1, 1, 10 µM) on N9 microglia after LPS treatment was evaluated. Inflammatory markers (TNF-α, IL-1ß, IL-6, CD86, IL-4, ARG-1, and CD206) were measured using qPCR. The levels of IBA1, ROS, NF-κB, TLR4, P-IKK, P-IκBα, and P65, MAPKs (ERK, JNK, and P38), NLRP3 (caspase-1, ASC, and NLRP3) were detected by Western blotting or immunofluorescence staining. The potential target of RUS was validated by molecular docking and adeno-associated virus injection. Mice in CFA group exhibited allodynia and anxiety-like behaviors. LPS induced neuroinflammation in N9 cells. Both CFA and LPS increased the levels of IBA1, ROS, and inflammatory markers. RUS (10 mg/kg in vivo and 1 µM in vitro) alleviated these alterations through NF-κB/MAPKs/NLRP3 signaling pathways but had no effect on pain hypersensitivity. TLR4 strongly interacted with RUS, and TLR4 overexpression abolished the effects of RUS on anxiety and neuroinflammation. RUS exerts anti-inflammatory and anxiolytic effects via TLR4-mediated NF-κB/MAPKs/NLRP3 signaling pathways, which provides a basis for the treatment of chronic pain-induced anxiety.
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Objectives: This study was conducted to explore the impact of 1, 8-cineole (eucalyptol) on the biochemical, molecular, and histological changes caused by lead acetate in the liver of adult male Wistar rats. The research also investigated the potential involvement of the TLR4 signaling pathway in this effect. Materials and Methods: Rats were orally administered lead acetate (25 mg/kg-day) for 14 consecutive days and received 1, 8-cineole (100 mg/kg-day) during the same period. Results: 1, 8-cineole prevented an increase in the malondialdehyde level, a decrease in the glutathione level, and a decrease in the activity of superoxide dismutase and glutathione peroxidase enzymes in the liver of rats treated with lead acetate. This monoterpene also prevented an increase in the expression of pro-inflammatory cytokines and significantly reduced the infiltration of inflammatory cells in the liver parenchyma. Additionally, 1, 8-cineole discouraged the increase in toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), and nuclear factor kappa B (NF-κB) expression in the liver and stopped a rise in serum AST and ALT enzymes. Conclusion: 1, 8-cineole can prevent liver damage caused by lead acetate by reducing oxidative stress and inflammation. This hepatoprotection is probably achieved by inhibiting TLR4/MyD88/NF-κB signaling.
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Schisandra chinensis, a traditional Chinese medicine, has been widely applied in China to treat diabetes and its complications. The aim of this study was to discover the active compounds and explain related molecular mechanism contributing to the anti-diabetic effect of Schisandra chinensis. Herein, the therapeutic effects of Schisandra chinensis extracts on type 2 diabetes mellitus (T2DM) were firstly confirmed in vivo. Subsequently, various lignans were isolated from Schisandra chinensis and tested for hypoglycemic activity in palmitic acid-induced insulin-resistant HepG2 (IR-HepG2) cells. Among these lignans, R-biar-(7S,8R)-6,7,8,9-tetrahydro-1,2,3,12,13,14-hexamethoxy-7,8-dimethyl-7-dibenzo [a, c] cyclooctenol (compound 2) and Gomisin A (compound 4) were identified significantly increased the glucose consumption in IR-HepG2 cells. Meanwhile, compounds 2 and 4 activated the insulin receptor substrate-1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/Ak strain transforming (AKT) pathway, which regulates glucose transporter 2 (GLUT2) and glucose-6-phosphatase (G6Pase), essential for gluconeogenesis and glucose uptake. These compounds also inhibited the nuclear factor-κB (NF-κB) signaling pathway, reducing interleukin-6 (IL-6) levels. Importantly, the hypoglycemic effects of compounds 2 and 4 were diminished after Toll-like receptor 4 (TLR4) knockdown. Cellular thermal shift assays confirmed increased TLR4 protein stability upon treatment with these compounds, indicating direct binding to TLR4. Furthermore, TLR4 knockdown reversed the effects of compounds 2 and 4 on the NF-κB and IRS-1/PI3K/AKT pathways. Taken together, compounds 2 and 4 alleviate IR by targeting TLR4, thereby modulating the NF-κB and IRS-1/PI3K/AKT pathways. These findings suggest that compounds 2 and 4 could be developed as therapeutic agents for T2DM.
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The mechanisms of how long-term alcohol use can lead to persistent pain pathology are unclear. Understanding how earlier events of short-term alcohol use can lower the threshold of non-painful stimuli, described as allodynia could prove prudent to understand important initiating mechanisms. Previously, we observed that short-term low-dose alcohol intake induced female-specific allodynia and increased microglial activation in the spinal cord dorsal horn. Other literature describes how chronic ethanol exposure activates Toll-like receptor 4 (TLR4) to initiate inflammatory responses. TLR4 is expressed on many cell types, and we aimed to investigate whether TLR4 on microglia is sufficient to potentiate allodynia during a short-term/low-dose alcohol paradigm. Our study used a novel genetic model where TLR4 expression is removed from the entire body by introducing a floxed transcriptional blocker (TLR4-null background (TLR4LoxTB)), then restricted to microglia by breeding TLR4LoxTB animals with Cx3CR1:CreERT2 animals. As previously reported, after 14 days of ethanol administration alone, we observed no increased pain behavior. However, we observed significant priming effects 3 hrs post intraplantar injection of a subthreshold dose of prostaglandin E2 (PGE2) in wild-type and microglia-TLR4 restricted female mice. We also observed a significant female-specific shift to pro-inflammatory phenotype and morphological changes in microglia of the lumbar dorsal horn. Investigations in pain priming-associated neuronal subtypes showed an increase of c-Fos and FosB activity in PKCγ interneurons in the dorsal horn of female mice directly corresponding to increased microglial activity. This study uncovers cell- and female-specific roles of TLR4 in sexual dimorphisms in pain induction among non-pathological drinkers.
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Dinoprostona , Etanol , Hiperalgesia , Microglía , Caracteres Sexuales , Médula Espinal , Receptor Toll-Like 4 , Animales , Microglía/metabolismo , Microglía/efectos de los fármacos , Femenino , Etanol/farmacología , Hiperalgesia/metabolismo , Receptor Toll-Like 4/metabolismo , Dinoprostona/metabolismo , Ratones , Masculino , Médula Espinal/metabolismo , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: While a number of anesthetics has been shown potentially associated with neurotoxicity in the developing brain, dexmedetomidine, a drug that was rather recently introduced into the perioperative setting, is considered beneficial from neurological wellbeing. However, the underlying mechanism of how dexmedetomidine affects brain health remains to be determined. Based on our recent study, we hypothesized that dexmedetomidine would directly bind to and inhibit Toll-like receptor 4 (TLR4), a critical receptor largely expressed in microglia and responsible for neurological insult. METHODS: We used TLR4 reporter assays to test if dexmedetomidine attenuates TLR4 activation. Furthermore, a direct binding of dexmedetomidine on TLR4 was tested using photoactivatable medetomidine. Lastly, the effect of dexmedetomidine on ketamine (anesthetic)-induced neurotoxicity was tested in rat pups (P7). RESULTS: We showed that dexmedetomidine attenuated TLR4 activation using reporter assay (IC50 = 5.8 µg/mL). Photoactivatable dexmedetomidine delineated its direct binding sites on TLR4. We also showed that dexmedetomidine attenuated microglia activation both in vitro and in vivo. DISCUSSION: We proposed a novel mechanism of dexmedetomidine-mediated neuroprotection.
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Dexmedetomidina , Microglía , Ratas Sprague-Dawley , Receptor Toll-Like 4 , Dexmedetomidina/farmacología , Animales , Receptor Toll-Like 4/metabolismo , Microglía/efectos de los fármacos , Microglía/metabolismo , Ratas , Humanos , Ketamina/farmacología , Unión Proteica , Fármacos Neuroprotectores/farmacología , Medetomidina/farmacología , Células HEK293RESUMEN
Transplantations represent the principal therapeutic interventions for terminal organ failure, a procedure that has salvaged myriad lives annually. Ischemia/reperfusion injury (IRI) is frequently correlated with an unfavourable prognosis and is relevant for early graft dysfunction and graft survival. IRI constitutes a complex pathological state influenced by a series of factors such as oxidative stress, metabolic stress, leukocytic infiltration, programmed cell death pathways, and inflammatory immune responses. Reducing ischemia/reperfusion injury is one of the main directions of transplantation research. Toll-like receptors (TLRs) are important pattern-recognition receptors expressed on various organs that orchestrate the immune responses upon recognising PAMPs and DAMPs. Targeting the TLR4 signalling has recently been suggested as a promising approach for alleviating IRI by affecting inflammation, oxidative stress and programmed cell death (PCD). In this minireview, we summarise the role of TLR4 signalling in regulating inflammation, oxidative stress and PCD in organ transplantation and discuss their interactions during IRI. A detailed understanding of the multiple functions of TLR4 in IRI provides novel insights into developing therapies to improve organ transplantation outcomes.
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Apoptosis , Inflamación , Trasplante de Órganos , Estrés Oxidativo , Daño por Reperfusión , Transducción de Señal , Receptor Toll-Like 4 , Daño por Reperfusión/metabolismo , Daño por Reperfusión/inmunología , Receptor Toll-Like 4/metabolismo , Humanos , Trasplante de Órganos/efectos adversos , Animales , Inflamación/inmunología , Inflamación/metabolismoRESUMEN
Recent evidence suggests that immune thrombocytopenia (ITP), a common bleeding disorder, is linked to an imbalance in macrophage polarization and impaired bone marrow mesenchymal stem cells (BMSCs). However, the relationship between macrophage polarization imbalance and functional defects in BMSCs, as well as the involvement of associated molecules in BMSCs' defects, is not well understood. This study aimed to investigate the regulatory effects of high mobility group protein 1 (HMGB1) on the physiological functions of BMSCs, specifically in relation to macrophage polarization imbalance. Patients with ITP showed dysregulation in monocyte/macrophage polarization and impaired BMSCs function. HMGB1 was found to have a negative impact on the ability of BMSCs to regulate the imbalance in macrophage polarization, especially when inflammatory factors are present. The MyD88-dependent pathway downstream of BMSCs was found to be significantly enhanced with HMGB1 treatment. Furthermore, treatment with toll-like receptor 4 (TLR4) inhibitors successfully restored the regulatory capacity of BMSCs in ameliorating macrophage polarization imbalance and effectively inhibited the activation of the MyD88-dependent pathway. Meanwhile, infusion of si-TLR4-BMSCs reversed HMGB1-induced platelet dysfunction and reduced over-polarization to M1-like macrophages in the ITP mouse model. Consequently, targeting the HMGB1-TLR4 pathway could be a potential approach to restore the immunoregulatory function of BMSCs.
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Objective: Sepsis-induced acute respiratory distress syndrome (ARDS) is an independent risk factor for mortality in critically ill septic patients. However, effective therapeutic targets are still unavailable due to the lack of understanding of its unclear pathogenesis. With increasing understanding in the roles of circulating histones and endothelial dysfunction in sepsis, we aimed to investigate the mechanism of histone-induced endothelial dysfunction leading to sepsis-induced ARDS and to provide experimental support for histone-targeted treatment of sepsis-induced ARDS. Methods: First of all, in vitro experiments were conducted. Human umbilical vein endothelial cells (HUVEC) were stimulated with gradient concentrations of histones to explore for the optimal stimulation concentration in vitro. Then, HUVEC were exposed to histones at an optimal concentration with or without resatorvid (TAK-242), a selective inhibitor of Toll-like receptor 4 (TLR4), for 24 hours for modeling. The cells were divided into 4 groups: 1) the blank control group, 2) the blank control+TAK-242 intervention group, 3) the histone stimulation group, and 4) the histone+TAK-242 intervention group. HUVEC apoptosis was determined by flow cytometry, VE-Cadherin expression in endothelial cells was determined by Western blot, and the integrity of adhesion connections between endothelial cells was evaluated with confocal fluorescence microscopic images. Male C57BL/6 mice aged 6-8 weeks and weighing 22-25 g were used for the in vivo experiment. Then, the mice were given cecal ligation and puncture (CLP) as well as histone injection at 50 mg/kg via the tail vein for sepsis modeling. The experimental animals were divided into 6 groups: 1) the blank control group, 2) the blank control+TAK-242 intervention group, 3) the CLP model group, 4) the CLP+TAK-242 intervention group, 5) the histone model group, and 6) the histone+TAK-242 intervention group. After 24 h, the concentrations of serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined using ELISA kits. Western blot was performed to determine the expression of vascular endothelial (VE)-cadherin in the lung tissue. Hematoxylin and eosin (HE) staining was performed to observe the pathological changes in the lung tissue of the mice. Evans Blue was injected via the tail vein 30 min before the mice were sacrificed. Lung tissue was collected after the mice were sacrificed. Then, the concentrations of Evans blue dye per unit mass in the lung tissue from mice of different groups were evaluated, the rates of pulmonary endothelial leakage were calculated, and the integrity of the pulmonary endothelial barrier was evaluated. Results: The results of the in vitro experiment showed that, compared with those of the control group, HUVEC apoptosis was significantly increased under histone stimulation (P<0.05), the expression of VE-cadherin was decreased (P<0.05), and the integrity of adherens junctions between endothelial cells was damaged. TAK-242 can significantly inhibit histone-induced HUVEC apoptosis and VE-cadherin expression reduction and maintain the integrity of adherens junctions between endothelial cells. According to the findings from the in vivo experiments, in mice with CLP-induced and histone-induced sepsis, TAK-242 effectively alleviated the increase in serum concentrations of IL-6 and TNF-α, reduced the downregulation of VE-cadherin expression in the lung tissue (P<0.05), decreased endothelial permeability of the lung vessels, and improved pathological injury in the lung tissue. Conclusion: By binding to TLR-4, histone decreases VE-cadherin expression on the surface of vascular endothelial cells, disrupts the integrity of intercellular adherens junctions, and triggers pathological damage to lung tissue. Using TLR-4 inhibitors can prevent sepsis-induced ARDS in histone-induced sepsis.
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Apoptosis , Histonas , Células Endoteliales de la Vena Umbilical Humana , Ratones Endogámicos C57BL , Síndrome de Dificultad Respiratoria , Sepsis , Receptor Toll-Like 4 , Sepsis/complicaciones , Sepsis/metabolismo , Síndrome de Dificultad Respiratoria/etiología , Síndrome de Dificultad Respiratoria/metabolismo , Humanos , Animales , Ratones , Histonas/metabolismo , Receptor Toll-Like 4/metabolismo , Masculino , Cadherinas/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Interleucina-6/metabolismo , Antígenos CD/metabolismo , SulfonamidasRESUMEN
In this study, we investigated whether the ability of aucubin to mitigate the pathology of GONFH involves suppression of TLR4/NF-κB signalling and promotion of macrophage polarization to an M2 phenotype. In necrotic bone tissues from GONFH patients, we compared levels of pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages as well as levels of TLR4/NF-κB signalling. In a rat model of GONFH, we examined the effects of aucubin on these parameters. We further explored its mechanism of action in a cell culture model of M1 macrophages. Necrotic bone tissues from GONFH patients contained a significantly increased macrophage M1/M2 ratio, and higher levels of TLR4, MYD88 and NF-κB p65 than bone tissues from patients with hip osteoarthritis. Treating GONFH rats with aucubin mitigated bone necrosis and demineralization as well as destruction of trabecular bone and marrow in a dose-dependent manner, based on micro-computed tomography. These therapeutic effects were associated with a decrease in the overall number of macrophages, decrease in the proportion of M1 macrophages, increase in the proportion of M2 macrophages, and downregulation of TLR4, MYD88 and NF-κB p65. These effects in vivo were confirmed by treating cultures of M1 macrophage-like cells with aucubin. Aucubin mitigates bone pathology in GONFH by suppressing TLR4/NF-κB signalling to shift macrophages from a pro- to anti-inflammatory phenotype.
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Glucósidos Iridoides , Macrófagos , Factor 88 de Diferenciación Mieloide , Transducción de Señal , Receptor Toll-Like 4 , Animales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ratas , Modelos Animales de Enfermedad , Necrosis de la Cabeza Femoral/inducido químicamente , Necrosis de la Cabeza Femoral/patología , Necrosis de la Cabeza Femoral/metabolismo , Necrosis de la Cabeza Femoral/tratamiento farmacológico , Glucocorticoides/farmacología , Glucósidos Iridoides/farmacología , Macrófagos/metabolismo , Macrófagos/efectos de los fármacos , Factor 88 de Diferenciación Mieloide/metabolismo , Factor 88 de Diferenciación Mieloide/genética , FN-kappa B/metabolismo , Fenotipo , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Receptor Toll-Like 4/metabolismoRESUMEN
Poor oral health is an independent risk factor for upper-aerodigestive tract cancers, including esophageal squamous cell carcinoma (ESCC). Our previous findings suggest that high expression of toll-like receptor (TLR) 4, which recognizes lipopolysaccharide (LPS) released from periodontal pathogens, correlates with a poor prognosis after esophagectomy for ESCC. We therefore hypothesized that LPS influences cancer cell proliferation and disease progression in ESCC. We used 8 ESCC cell lines to investigate how LPS affects ESCC cell proliferation and migration activity. We also assessed mRNA and protein expression to determine how LPS affects cytokine production and whether blocking TLR4 signaling attenuates that effect. We also used a mouse xenograft model to investigate whether LPS upregulates ESCC tumor progression in vivo. We then determined whether C-C motif chemokine ligand 2 (CCL2) expression in clinical samples correlates with 5-year overall survival (OS) and disease-specific survival (DSS) in ESCC patients after esophagectomy. LPS significantly upregulated cell proliferation and migration in all ESCC lines. It also upregulated CCL2 production. In vivo, subcutaneous LPS administration significantly increased ESCC tumor volume in mice. In clinical samples, high CCL2 expression significantly correlated with 5-year OS and DSS. There was also a significant correlation between CCL2 and TLR4 expression status, suggesting the involvement of an LPS-TLR4-CCL2 cascade in clinical settings. LPS significantly upregulates cell proliferation and tumor progression through an LPS-TLR4-CCL2 cascade and influences prognosis after esophagectomy for ESCC. This suggests improving the oral environment has the potential to improve the prognosis of ESCC patients after esophagectomy.
RESUMEN
Efforts to reveal the molecular, cellular, and circuit mechanisms of addiction have largely focused on neurons. Yet accumulating data regarding the ability of glial cells to impact synaptic function, circuit activity, and behavior demands that we explore how these nonneuronal cells contribute to substance use disorders and addiction. Important work has shown that glial cells, including microglia, exhibit changes in phenotype following exposure to drugs of abuse and that modification of glial responses can impact behaviors related to drug seeking and drug taking. While these are critical first steps to understanding how microglia can impact addiction, there are still substantial gaps in knowledge that need to be addressed. This chapter reviews some of the key studies that have shown how microglia are affected by and can contribute to addiction. It also discusses areas where more knowledge is urgently needed to reveal new therapeutic and preventative approaches.
Asunto(s)
Conducta Adictiva , Microglía , Trastornos Relacionados con Sustancias , Humanos , Trastornos Relacionados con Sustancias/epidemiología , Microglía/metabolismo , Animales , Neuronas/metabolismo , Neuroglía/metabolismoRESUMEN
BACKGROUND: Most acute cerebral infarctions (ACI) may develop vascular dementia (VD), which involves almost all types of cognitive impairment. Unfortunately, there is currently no effective treatment for VD. Most patients exhibit mild cognitive impairment (MCI) before the development of VD. N-butyl-phthalide (NBP) is used to treat ACI and improve cognitive function. The oxygen and glucose deprivation (OGD) model of neurons is an in vitro model of ischemia, hypoxia, and cognitive dysfunction. METHODS: We conducted clinical studies and in vitro experiments to investigate the clinical efficacy and mechanism of action of NBP for treating ACI-induced MCI. Patients with ACI-induced MCI were randomly divided into control (Ctrl) and NBP groups. We assessed various indicators, such as clinical efficacy, montreal cognitive assessment scale (MOCA), activities of daily living (ADL), and cerebral infarct size in both groups before and after treatment. We observed the morphology of neurons and detected the survival rate, action potentials (APs), expression of high mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), and the interaction between TLR4 and HMGB1. RESULTS: The MOCA and ADL scores increased significantly after treatment in the NBP group. A OGD model of neurons was established, and the neurons were divided into Ctrl and NBP groups. We observed that the survival rate and APs amplitude of the neurons were significantly increased in the NBP group, whereas TNF-α expression was decreased. Furthermore, the interaction between TLR4 and HMGB1 decreased in the NBP group. CONCLUSION: NBP plays a neuroprotective role by inhibiting the TLR4/HMGB1 pathway and ameliorating ACI-induced MCI.