RESUMO
A hallmark feature of inflammation is the orchestrated recruitment of neutrophils from the bloodstream into inflamed tissue. Although selectins and integrins mediate recruitment in many tissues, they have a minimal role in the lungs and liver. Exploiting an unbiased in vivo functional screen, we identified a lung and liver homing peptide that functionally abrogates neutrophil recruitment to these organs. Using biochemical, genetic, and confocal intravital imaging approaches, we identified dipeptidase-1 (DPEP1) as the target and established its role as a physical adhesion receptor for neutrophil sequestration independent of its enzymatic activity. Importantly, genetic ablation or functional peptide blocking of DPEP1 significantly reduced neutrophil recruitment to the lungs and liver and provided improved survival in models of endotoxemia. Our data establish DPEP1 as a major adhesion receptor on the lung and liver endothelium and identify a therapeutic target for neutrophil-driven inflammatory diseases of the lungs.
Assuntos
Dipeptidases/metabolismo , Neutrófilos/fisiologia , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Animais , Cilastatina/farmacologia , Cilastatina/uso terapêutico , Dipeptidases/antagonistas & inibidores , Dipeptidases/genética , Modelos Animais de Doenças , Endotoxemia/mortalidade , Endotoxemia/patologia , Endotoxemia/prevenção & controle , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Humanos , Lipopolissacarídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/imunologia , Fígado/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos SCID , Infiltração de Neutrófilos/efeitos dos fármacos , Peptídeos/síntese química , Peptídeos/química , Peptídeos/farmacologia , Taxa de SobrevidaRESUMO
Caspase-11, a cytosolic endotoxin (lipopolysaccharide: LPS) receptor, mediates pyroptosis, a lytic form of cell death. Caspase-11-dependent pyroptosis mediates lethality in endotoxemia, but it is unclear how LPS is delivered into the cytosol for the activation of caspase-11. Here we discovered that hepatocyte-released high mobility group box 1 (HMGB1) was required for caspase-11-dependent pyroptosis and lethality in endotoxemia and bacterial sepsis. Mechanistically, hepatocyte-released HMGB1 bound LPS and targeted its internalization into the lysosomes of macrophages and endothelial cells via the receptor for advanced glycation end-products (RAGE). Subsequently, HMGB1 permeabilized the phospholipid bilayer in the acidic environment of lysosomes. This resulted in LPS leakage into the cytosol and caspase-11 activation. Depletion of hepatocyte HMGB1, inhibition of hepatocyte HMGB1 release, neutralizing extracellular HMGB1, or RAGE deficiency prevented caspase-11-dependent pyroptosis and death in endotoxemia and bacterial sepsis. These findings indicate that HMGB1 interacts with LPS to mediate caspase-11-dependent pyroptosis in lethal sepsis.
Assuntos
Caspases/imunologia , Endotoxinas/imunologia , Proteína HMGB1/imunologia , Piroptose/imunologia , Sepse/imunologia , Animais , Caspases/genética , Caspases/metabolismo , Células Cultivadas , Células Endoteliais/imunologia , Células Endoteliais/metabolismo , Endotoxinas/metabolismo , Células HEK293 , Proteína HMGB1/genética , Proteína HMGB1/metabolismo , Humanos , Lipopolissacarídeos/imunologia , Lipopolissacarídeos/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptor para Produtos Finais de Glicação Avançada/imunologia , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Sepse/genética , Sepse/metabolismo , Células THP-1RESUMO
Neutrophils are among the fastest-moving immune cells. Their speed is critical to their function as 'first responder' cells at sites of damage or infection, and it has been postulated that the unique segmented nucleus of neutrophils functions to assist their rapid migration. Here, we tested this hypothesis by imaging primary human neutrophils traversing narrow channels in custom-designed microfluidic devices. Individuals were given an intravenous low dose of endotoxin to elicit recruitment of neutrophils into the blood with a high diversity of nuclear phenotypes, ranging from hypo- to hyper-segmented. Both by cell sorting of neutrophils from the blood using markers that correlate with lobularity and by directly quantifying the migration of neutrophils with distinct lobe numbers, we found that neutrophils with one or two nuclear lobes were significantly slower to traverse narrower channels, compared to neutrophils with more than two nuclear lobes. Thus, our data show that nuclear segmentation in primary human neutrophils provides a speed advantage during migration through confined spaces.
Assuntos
Núcleo Celular , Neutrófilos , Humanos , Neutrófilos/fisiologia , Movimento Celular/fisiologiaRESUMO
This review provides an update on recent findings from basic, translational, and clinical studies on the molecular mechanisms of mitochondrial dysfunction and apoptosis of hepatocytes in multiple liver diseases, including but not limited to alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and drug-induced liver injury (DILI). While the ethanol-inducible cytochrome P450-2E1 (CYP2E1) is mainly responsible for oxidizing binge alcohol via the microsomal ethanol oxidizing system, it is also responsible for metabolizing many xenobiotics, including pollutants, chemicals, drugs, and specific diets abundant in n-6 fatty acids, into toxic metabolites in many organs, including the liver, causing pathological insults through organelles such as mitochondria and endoplasmic reticula. Oxidative imbalances (oxidative stress) in mitochondria promote the covalent modifications of lipids, proteins, and nucleic acids through enzymatic and non-enzymatic mechanisms. Excessive changes stimulate various post-translational modifications (PTMs) of mitochondrial proteins, transcription factors, and histones. Increased PTMs of mitochondrial proteins inactivate many enzymes involved in the reduction of oxidative species, fatty acid metabolism, and mitophagy pathways, leading to mitochondrial dysfunction, energy depletion, and apoptosis. Unique from other organelles, mitochondria control many signaling cascades involved in bioenergetics (fat metabolism), inflammation, and apoptosis/necrosis of hepatocytes. When mitochondrial homeostasis is shifted, these pathways become altered or shut down, likely contributing to the death of hepatocytes with activation of inflammation and hepatic stellate cells, causing liver fibrosis and cirrhosis. This review will encapsulate how mitochondrial dysfunction contributes to hepatocyte apoptosis in several types of liver diseases in order to provide recommendations for targeted therapeutics.
Assuntos
Gastroenteropatias , Hepatopatias Alcoólicas , Doenças Mitocondriais , Humanos , Fígado/metabolismo , Etanol/farmacologia , Apoptose , Estresse Oxidativo , Inflamação/patologia , Gastroenteropatias/metabolismo , Hepatócitos/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Mitocondriais/metabolismo , Doenças Mitocondriais/metabolismoRESUMO
BACKGROUND: Cognitive dysfunction caused by infection frequently emerges as a complication in sepsis survivor patients. However, a comprehensive understanding of its pathogenesis remains elusive. METHODS: In our in vivo experiments, an animal model of endotoxemia was employed, utilizing the Novel Object Recognition Test and Morris Water Maze Test to assess cognitive function. Various techniques, including immunofluorescent staining, Western blotting, bloodâbrain barrier permeability assessment, Limulus Amebocyte Lysate (LAL) assay, and Proximity-ligation assay, were employed to identify brain pathological injury and neuroinflammation. To discern the role of Caspase-11 (Casp11) in hematopoietic or non-hematopoietic cells in endotoxemia-induced cognitive decline, bone marrow chimeras were generated through bone marrow transplantation (BMT) using wild-type (WT) and Casp11-deficient mice. In vitro studies involved treating BV2 cells with E. coli-derived outer membrane vesicles to mimic in vivo conditions. RESULTS: Our findings indicate that the deficiency of Casp11-GSDMD signaling pathways reverses infection-induced cognitive dysfunction. Moreover, cognitive dysfunction can be ameliorated by blocking the IL-1 effect. Mechanistically, the absence of Casp11 signaling significantly mitigated bloodâbrain barrier leakage, microglial activation, and synaptic damage in the hippocampal CA3 region, ultimately leading to improved cognitive function. CONCLUSION: This study unveils the crucial contribution of Casp11 and GSDMD to cognitive impairments and spatial memory loss in a murine sepsis model. Targeting Casp11 signaling emerges as a promising strategy for preventing or treating cognitive dysfunction in patients with severe infections.
Assuntos
Caspases Iniciadoras , Caspases , Disfunção Cognitiva , Modelos Animais de Doenças , Transdução de Sinais , Animais , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/metabolismo , Camundongos , Caspases/metabolismo , Caspases Iniciadoras/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Proteínas de Ligação a Fosfato/genética , Barreira Hematoencefálica/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Endotoxemia/complicações , Endotoxemia/metabolismo , Endotoxemia/etiologia , Hipocampo/metabolismo , Hipocampo/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Sepse/complicações , Sepse/metabolismo , GasderminasRESUMO
BACKGROUND: The involvement of the autonomic nervous system in the regulation of inflammation is an emerging concept with significant potential for clinical applications. Recent studies demonstrate that stimulating the vagus nerve activates the cholinergic anti-inflammatory pathway that inhibits pro-inflammatory cytokines and controls inflammation. The α7 nicotinic acetylcholine receptor (α7nAChR) on macrophages plays a key role in mediating cholinergic anti-inflammatory effects through a downstream intracellular mechanism involving inhibition of NF-κB signaling, which results in suppression of pro-inflammatory cytokine production. However, the role of the α7nAChR in the regulation of other aspects of the immune response, including the recruitment of monocytes/macrophages to the site of inflammation remained poorly understood. RESULTS: We observed an increased mortality in α7nAChR-deficient mice (compared with wild-type controls) in mice with endotoxemia, which was paralleled with a significant reduction in the number of monocyte-derived macrophages in the lungs. Corroborating these results, fluorescently labeled α7nAChR-deficient monocytes adoptively transferred to WT mice showed significantly diminished recruitment to the inflamed tissue. α7nAChR deficiency did not affect monocyte 2D transmigration across an endothelial monolayer, but it significantly decreased the migration of macrophages in a 3D fibrin matrix. In vitro analysis of major adhesive receptors (L-selectin, ß1 and ß2 integrins) and chemokine receptors (CCR2 and CCR5) revealed reduced expression of integrin αM and αX on α7nAChR-deficient macrophages. Decreased expression of αMß2 was confirmed on fluorescently labeled, adoptively transferred α7nAChR-deficient macrophages in the lungs of endotoxemic mice, indicating a potential mechanism for α7nAChR-mediated migration. CONCLUSIONS: We demonstrate a novel role for the α7nAChR in mediating macrophage recruitment to inflamed tissue, which indicates an important new aspect of the cholinergic regulation of immune responses and inflammation.
Assuntos
Endotoxemia , Receptor Nicotínico de Acetilcolina alfa7 , Camundongos , Animais , Receptor Nicotínico de Acetilcolina alfa7/genética , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Macrófagos/metabolismo , Inflamação/metabolismo , Citocinas/metabolismo , Endotoxemia/metabolismo , Colinérgicos/metabolismoRESUMO
BACKGROUND: Circulating endotoxins could result from bacterial digestive translocation during sepsis, thus contributing to uncontrolled systemic inflammation, leading in turn to organ dysfunction. We addressed this issue in the setting of severe pneumococcal pneumonia. METHODS: Endotoxemia was measured in a clinically relevant rabbit model of ventilated pneumococcal pneumonia and in 110 patients with bacteraemic pneumonia, using a patented mass spectrometry (LC-MS/MS) method for detection of 3-OH fatty acids (C10, C12, C14, C16 and C18), which are molecules bound to the lipid A motif of LPS. RESULTS: Whereas higher levels of systemic inflammation and organ dysfunctions were found, there was no significant difference in lipopolysaccharide concentrations when infected rabbits were compared to non-infected ones, or when patients were compared to healthy volunteers. CONCLUSIONS: Seemingly, endotoxins do not drive the overwhelming inflammation associated with severe forms of pneumococcal pneumonia.
Assuntos
Endotoxemia , Pneumonia Pneumocócica , Humanos , Animais , Coelhos , Pneumonia Pneumocócica/diagnóstico , Cromatografia Líquida , Espectrometria de Massas em Tandem , Inflamação , Lipopolissacarídeos , EndotoxinasRESUMO
BACKGROUND: Thrombomodulin (TM) exerts anticoagulant and anti-inflammatory effects to improve the survival of patients with septic shock. Heat stroke resembles septic shock in many aspects. We tested whether TM would improve cognitive deficits and related causative factors in heat-stressed (HS) mice. METHODS: Adult male mice were exposed to HS (33°C for 2 hours daily for 7 consecutive days) to induce cognitive deficits. Recombinant human soluble TM (1 mg/kg, i.p.) was administered immediately after the first HS trial and then once daily for 7 consecutive days. We performed the Y-maze, novel objective recognition, and passive avoidance tests to evaluate cognitive function. Plasma levels of lipopolysaccharide (LPS), high-mobility group box 1 (HMGB1), coagulation parameters, and both plasma and tissue levels of inflammatory and oxidative stress markers were biochemically measured. The duodenum and hippocampus sections were immunohistochemically stained. The intestinal and blood-brain barrier permeability were determined. RESULTS: Compared with controls, HS mice treated with TM had lesser extents of cognitive deficits, exacerbated stress reactions, gut barrier disruption, endotoxemia, blood-brain barrier disruption, and inflammatory, oxidative, and coagulatory injury to heart, duodenum, and hippocampal tissues, and increased plasma HMGB1. In addition to reducing cognitive deficits, TM therapy alleviated all the abovementioned complications in heat-stressed mice. CONCLUSIONS: The findings suggest that HS can lead to exacerbated stress reactions, endotoxemia, gut barrier disruption, blood-brain barrier disruption, hippocampal inflammation, coagulopathy, and oxidative stress, which may act as causative factors for cognitive deficits. TM, an anti-inflammatory, antioxidant, and anti-coagulatory agent, inhibited heat stress-induced cognitive deficits in mice.
Assuntos
Disfunção Cognitiva , Proteína HMGB1 , Trombomodulina , Animais , Masculino , Proteína HMGB1/metabolismo , Proteína HMGB1/sangue , Camundongos , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/fisiopatologia , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Modelos Animais de Doenças , Aprendizagem da Esquiva/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Resposta ao Choque Térmico/efeitos dos fármacos , Resposta ao Choque Térmico/fisiologia , Aprendizagem em Labirinto/efeitos dos fármacosRESUMO
BACKGROUND: Obesity and consumption of high-fat diets (HFD) are associated with intestinal permeabilization and increased paracellular transport of endotoxins, which can promote neuroinflammation. Inflammation can affect the hypothalamic pituitary adrenal (HPA) axis, which controls responses to stress and downregulates the brain-derived neurotrophic factor (BDNF), which can promote anxiety and depression, conditions frequently found in obesity. We previously showed that consumption of anthocyanins (AC) mitigate HFD-induced insulin resistance, intestinal permeability, and inflammation. OBJECTIVES: This study investigated if a dietary supplementation with a cyanidin- and delphinidin-rich extract (CDRE) could counteract HFD/obesity-induced hippocampal inflammation in mice. METHODS: C57BL/6J male mice were fed for 14 wk on one of the following diets: 1) a control diet containing 10% total calories from fat (C), 2) a control diet supplemented with 40 mg AC/kg body weight (BW) (CAC), 3) a HFD containing 60% total calories from fat (lard) (HF), or 4) the HFD supplemented with 2, 20, or 40 mg AC/kg BW (HFA2, HFA20, and HFA40, respectively). In plasma and in the hippocampus, parameters of neuroinflammation and the underlying cause (endotoxemia) and consequences (alterations to the HPA and BDNF downregulation) were measured. RESULTS: Consumption of the HFD caused endotoxemia. Accordingly, hippocampal Tlr4 mRNA levels were 110% higher in the HF group, which were both prevented by CDRE supplementation. Consumption of the HFD also caused: 1) microgliosis and increased expression of genes involved in neuroinflammation, that is, Iba-1, Nox4, Tnfα, and Il-1ß, 2) alterations of HPA axis regulation, that is, with low expression of mineralocorticoid (MR) and glucocorticoid (GR) receptors; and 3) decreased Bdnf expression. Supplementation of HFD-fed mice with CDRE mitigated neuroinflammation, microgliosis, and MR and BDNF decreases. CONCLUSIONS: CDRE supplementation mitigates the negative effects associated with HFD consumption and obesity in mouse hippocampus, in part by decreasing inflammation, improving glucocorticoid metabolism, and upregulating BDNF.
Assuntos
Antocianinas , Dieta Hiperlipídica , Hipocampo , Inflamação , Camundongos Endogâmicos C57BL , Animais , Antocianinas/farmacologia , Dieta Hiperlipídica/efeitos adversos , Masculino , Hipocampo/metabolismo , Hipocampo/efeitos dos fármacos , Camundongos , Inflamação/prevenção & controle , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/genética , Obesidade , Suplementos NutricionaisRESUMO
Sepsis-induced myocardial depression (SIMD) is common in pediatric intensive care units and seriously threatens children's health. Recently, long noncoding RNAs (lncRNAs) have been showed to play important roles in various diseases; however, its role in SIMD is unclear. In this study, we used lipopolysaccharide (LPS)-treated rats and H9c2 cardiomyocytes to mimic SIMD in vivo and in vitro. We found that the expression of a novel lncRNA, we named lncRNA-AABR07066529.3, was elevated in LPS-induced rat heart tissue and H9c2 cardiomyocytes. In addition, LPS-induced inflammation, apoptosis, and pyroptosis were significantly exacerbated after lncRNA-AABR07066529.3 knockdown. Moreover, we found that myeloid differentiation factor 88 (MyD88) was upregulated in LPS-treated groups and was inhibited by lncRNA-AABR07066529.3. Besides, MyD88 knockdown abolished lncRNA-AABR07066529.3 silencing effects on inflammation, apoptosis, and pyroptosis induced by LPS in H9c2 cardiomyocytes. In our study, we found lncRNA-AABR07066529.3 exerted protective effects on LPS-induced cardiomyocytes by regulating MyD88 and might serve as a potential treatment target for SIMD.
Assuntos
Cardiomiopatias , MicroRNAs , RNA Longo não Codificante , Animais , Ratos , Apoptose , Cardiomiopatias/metabolismo , Depressão , Inflamação/induzido quimicamente , Inflamação/genética , Inflamação/metabolismo , Lipopolissacarídeos/farmacologia , MicroRNAs/genética , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Miócitos Cardíacos/metabolismo , Piroptose/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
Social withdrawal is a well-established part of sickness behavior, but in some contexts sick animals might gain from keeping close instead of keeping away. For instance, sick individuals are more willing to be near known individuals who can provide care and safety (close others) compared to when healthy. Yet, interactions with some strangers might also be beneficial (i.e., healthcare professionals), but it is not known how sickness interplay with social behavior towards such individuals. Here, we assessed if sickness affects perception of caregivers, and developed a new task, the Caregiver Perception Task (CgPT). Twenty-six participants performed the CgPT, once after an injection of lipopolysaccharide (LPS, 0.8 ng/kg body weight, n = 24), and once after an injection of saline (n = 25), one hour and forty-five minutes post-injection. During the task, participants watched short video clips of three types of caregivers: a healthcare professional taking care of a sick individual, a healthcare professional not taking care of a sick individual, and a non-healthcare professional taking care of their sick adult child or partner. After each video clip, the likability, trustworthiness, professionalism, and willingness to interact with and receive care from the caregiver were rated on visual analogue scales. Results showed that participants injected with saline rated healthcare professionals who did not take care of a sick individual less positively on all aspects compared to healthcare professionals who took care of a sick individual. Moreover, compared to saline, LPS increased the participants' willingness to receive care from healthcare professionals and non-healthcare professionals providing care, but not from healthcare professionals not providing care. Thus, our results indicate that sick individuals may approach unknown individuals with potential to provide care and support.
Assuntos
Cuidadores , Endotoxemia , Comportamento de Doença , Lipopolissacarídeos , Humanos , Masculino , Cuidadores/psicologia , Feminino , Adulto , Endotoxemia/psicologia , Adulto Jovem , Percepção/fisiologia , Comportamento SocialRESUMO
Bacterial lipopolysaccharide (LPS) induces general inflammation, by activating pathways involving cytokine production, blood coagulation, complement system activation, and acute phase protein release. The key cellular players are leukocytes and endothelial cells, that lead to tissue injury and organ failure. The aim of this study was to explore the anti-inflammatory, antioxidant, and cytoprotective properties of two bile acids, ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) in LPS-induced endotoxemia in rats. The experiment involved six distinct groups of Wistar rats, each subjected to different pretreatment conditions: control and LPS groups were pretreated with propylene glycol, as a bile acid solvent, while the other groups were pretreated with UDCA or CDCA for 10 days followed by an LPS injection on day 10. The results showed that both UDCA and CDCA reduced the production of pro-inflammatory cytokines: TNF-α, GM-CSF, IL-2, IFNγ, IL-6, and IL-1ß and expression of nuclear factor-κB (NF-κB) induced by LPS. In addition, pretreatment with these bile acids showed a positive impact on lipid profiles, a decrease in ICAM levels, an increase in antioxidant activity (SOD, |CAT, GSH), and a decrease in prooxidant markers (H2O2 and O2-). Furthermore, both bile acids alleviated LPS-induced liver injury. While UDCA and CDCA pretreatment attenuated homocysteine levels in LPS-treated rats, only UDCA pretreatment showed reductions in other serum biochemical markers, including creatine kinase, lactate dehydrogenase, and high-sensitivity troponin I. It can be concluded that both, UDCA and CDCA, although exerted slightly different effects, can prevent the inflammatory responses induced by LPS, improve oxidative stress status, and attenuate LPS-induced liver injury.
RESUMO
PURPOSE: Gut barrier dysfunction is a pivotal pathophysiological alteration in cirrhosis and end-stage liver disease, which is further aggravated during and after the operational procedures for liver transplantation (LT). In this review, we analyze the multifactorial disruption of all major levels of defense of the gut barrier (biological, mechanical, and immunological) and correlate with clinical implications. METHODS: A narrative review of the literature was performed using PubMed, PubMed Central and Google from inception until November 29th, 2023. RESULTS: Systemic translocation of indigenous bacteria through this dysfunctional barrier contributes to the early post-LT infectious complications, while endotoxin translocation, through activation of the systemic inflammatory response, is implicated in non-infectious complications including renal dysfunction and graft rejection. Bacterial infections are the main cause of early in-hospital mortality of LT patients and unraveling the pathophysiology of gut barrier failure is of outmost importance. CONCLUSION: A pathophysiology-based approach to prophylactic or therapeutic interventions may lead to enhancement of gut barrier function eliminating its detrimental consequences and leading to better outcomes for LT patients.
Assuntos
Microbioma Gastrointestinal , Transplante de Fígado , Complicações Pós-Operatórias , Humanos , Transplante de Fígado/efeitos adversos , Complicações Pós-Operatórias/fisiopatologia , Translocação BacterianaRESUMO
BACKGROUND: Sepsis is associated with high morbidity and mortality, primarily due to systemic inflammation-induced tissue damage, resulting organ failure, and impaired recovery. Regulated extracellular matrix (ECM) turnover is crucial for maintaining tissue homeostasis in health and in response to disease-related changes in the tissue microenvironment. Conversely, uncontrolled turnover can contribute to tissue damage. Systemic Inflammation is implicated to play a role in the regulation of ECM turnover, but the relationship between the two is largely unclear. METHODS: We performed an exploratory study in 10 healthy male volunteers who were intravenously challenged with 2 ng/kg lipopolysaccharide (LPS, derived from Escherichia coli) to induce systemic inflammation. Plasma samples were collected before (T0) and after (T 1 h, 3 h, 6 h and 24 h) the LPS challenge. Furthermore, plasma was collected from 43 patients with septic shock on day 1 of ICU admission. Circulating neo-epitopes of extracellular matrix turnover, including ECM degradation neo-epitopes of collagen type I (C1M), type III (C3M), type IV (C4Ma3), and type VI (C6M), elastin (ELP-3) and fibrin (X-FIB), as well as the ECM synthesis neo-epitopes of collagen type III (PRO-C3), collagen type IV (PRO-C4) and collagen type VI (PRO-C6) were measured by ELISA. Patient outcome data were obtained from electronic patient records. RESULTS: Twenty-four hours after LPS administration, all measured ECM turnover neo-epitopes, except ELP-3, were increased compared to baseline levels. In septic shock patients, concentrations of all measured ECM neo-epitopes were higher compared to healthy controls. In addition, concentrations of C6M, ELP-3 and X-FIB were higher in patients with septic shock who ultimately did not survive (N = 7) compared to those who recovered (N = 36). CONCLUSION: ECM turnover is induced in a model of systemic inflammation in healthy volunteers and was observed in patients with septic shock. Understanding interactions between systemic inflammation and ECM turnover may provide further insight into mechanisms underlying acute and persistent organ failure in sepsis.
Assuntos
Sepse , Choque Séptico , Humanos , Masculino , Lipopolissacarídeos , Matriz Extracelular , Epitopos , Escherichia coliRESUMO
PURPOSE: Individuals with vitamin D (VD) insufficiency have a greater tendency to develop obesity and have increased systemic inflammation. Gut microbiota are involved in the regulation of host inflammation and energy metabolism, which plays a role in the pathogenesis of obesity. Thus, we aimed to evaluate the effects of different doses of VD3 on body weight, serum lipids, inflammatory factors, and intestinal barrier function in obese mice and to explore the regulatory effect of VD3 on gut microbiota in obese mice. METHODS: Male C57BL/6 J mice received a normal chow diet (NCD, 10% fat) or high-fat diet (HFD, 60% fat) to induce obesity within 10 weeks. Then, HFD mice were supplemented with 5650, 8475, or 11,300 IU VD3/kg diet for 8 weeks. Finally, 16 s rRNA analysis was performed to analyze gut microbiota composition in cecal contents. In addition, body weight, serum lipids, inflammatory factors, and intestinal barrier function were analyzed. RESULTS: VD3 supplementation reduced body weight and the levels of TG, TC, HDL-C, TNF-α, IL-1ß and LPS, and increased ZO-1 in HFD-fed mice. Moreover, it increased α-diversity, reduced F/B ratio and altered microbiota composition by increasing relative abundance of Bacteroidetes, Proteobacteria, Desulfovibrio, Dehalobacterium, Odoribacter, and Parabacteroides and reducing relative abundance of Firmicutes and Ruminococcus. There were significant differences between HFD and NCD groups in several metabolic pathways, including endotoxin biosynthesis, tricarboxylic acid cycle, lipid synthesis and metabolism, and glycolysis. CONCLUSIONS: Low, medium, and high doses of VD3 inhibited weight gain, reduced levels of blood lipids and inflammatory factors, and improved endotoxemia and gut barrier function in obese mice. It also increased the α-diversity of gut microbiota in obese mice and reduced the relative abundance of some intestinal pathogenic bacteria, increased the relative abundance of some beneficial bacteria, and corrected the intestinal flora disorder of obese mice, with the low- and high-dose groups showing better effects than the medium-dose group.
Assuntos
Microbioma Gastrointestinal , Doenças não Transmissíveis , Masculino , Camundongos , Animais , Dieta Hiperlipídica/efeitos adversos , Colecalciferol/farmacologia , Camundongos Obesos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Peso Corporal , Inflamação/complicações , Lipídeos , Suplementos NutricionaisRESUMO
This study investigated the effect of N-acetylcysteine (NAC) and silymarin (SIL) in the liver of mice exposed to ethanol and lipopolysaccharides (LPS). Mice were divided into four groups (n = 6): naive, vehicle, NAC (200 mg/kg), and SIL (200 mg/kg). Treatments were given orally (po) once daily for 10 days. Liver injury was induced by administration of ethanol (30%, po) for 10 days, once daily, followed by a single administration of LPS (2 mg/kg, ip) 24 h before euthanasia. After the treatment period, animals were euthanized, and liver and blood samples were collected. NAC, but not SIL, prevented the increase in oxalacetic glutamic transaminase (OGT) and pyruvic glutamic transaminase (PGT) serum levels. NAC and SIL did not restore levels of reduced glutathione or hepatic malonaldehyde. The treatments with NAC or SIL showed no difference in the activity of glutathione S-transferase, superoxide dismutase, and catalase compared to vehicle group. Myeloperoxidase and N-acetylglucosaminidase activities are increased, as well as the IL-6 and IL-10 levels in the liver. The treatment with NAC, but not SIL, reduced the N-acetylglucosamines activity and the IL-6 and IL-10 amount in the liver. Histological findings revealed microsteatosis in the vehicle group, which was not prevented by SIL but was partially reduced in animals receiving NAC. Unlike other liver injury models, NAC (200 mg/kg) or SIL (200 mg/kg) did not positively affect antioxidant patterns in liver tissue of animals exposed to ethanol plus LPS, but NAC treatment displays anti-inflammatory properties in this model.
Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Silimarina , Camundongos , Animais , Acetilcisteína/farmacologia , Silimarina/farmacologia , Lipopolissacarídeos/toxicidade , Interleucina-10 , Etanol/toxicidade , Doença Hepática Crônica Induzida por Substâncias e Drogas/patologia , Interleucina-6/farmacologia , Fígado/patologia , Antioxidantes/farmacologia , Glutationa , Transaminases/farmacologiaRESUMO
The aim of the present study was to determine the efficacy of LAB strains in reducing the intestinal toxicity of arsenite [As(III)] and its tissue accumulation. For this purpose, Balb/c mice were randomly separated in four groups. One group received no treatment (control), one group received only As(III) (30 mg/L) via drinking water and the remaining two groups received As(III) via water and a daily dose of two LAB strains (Lactobacillus intestinalis LE1 and Lacticaseibacillus paracasei BL23) by gavage during 2 months. The results show that both strains reduce the pro-inflammatory and pro-oxidant response observed at the colonic level, partially restore the expression of the intercellular junction proteins (CLDN3 and OCLN) responsible for the maintenance of epithelial integrity, and increase the synthesis of the major mucin of the colonic mucus layer (MUC2), compared to animals treated with As(III) alone. Microbial metabolism of short-chain fatty acids also undergoes a recovery and the levels of fatty acids in the lumen reach values similar to those of untreated animals. All these positive effects imply the restoration of mucosal permeability, and a reduction of the marker of endotoxemia LPS binding protein (LBP). Treatment with the bacteria also has a direct impact on intestinal absorption, reducing the accumulation of As in the internal organs. The data suggest that the protective effect may be due to a reduced internalization of As(III) in intestinal tissues and to a possible antioxidant and anti-inflammatory activity of the bacteria through activation of pathways such as Nrf2 and IL-10. In vitro tests show that the protection may be the result of the combined action of structural and metabolic components of the LAB strains.
Assuntos
Arsenitos , Água Potável , Camundongos , Animais , Mucosa Intestinal/metabolismo , Arsenitos/toxicidade , Lactobacillus , BactériasRESUMO
Obstructive sleep apnea (OSA) can lead to intestinal injury, endotoxemia, and disturbance of intestinal flora. Additionally, as a crucial component of the endocannabinoid system, some studies have demonstrated that cannabinoid 1 (CB1) receptors are closely linked to the multiple organ dysfunction triggered by OSA. However, the role of the CB1 receptor in alleviating OSA-induced colon injury remains unclear. Here, through the construction of the OSA classic model, we found that the colon tissue of chronic intermittent hypoxia (CIH)-induced mice exhibited an overexpression of the CB1 receptor. The results of hematoxylin-eosin staining and transmission electron microscopy revealed that inhibition of the CB1 receptor could decrease the gap between the mucosa and muscularis mucosae, alleviate mitochondrial swelling, reduce microvilli shedding, and promote the recovery of tight junctions of CIH-induced mice. Furthermore, CB1 receptor inhibition reduced the levels of metabolic endotoxemia and inflammatory responses, exhibiting significant protective effects on the colon injury caused by CIH. At the molecular level, through western blotting and real-time polymerase chain reaction techniques, we found that inhibiting the CB1 receptor can significantly increase the expression of ZO-1 and Occludin proteins, which are closely related to the maintenance of intestinal mucosal barrier function. Through 16S rRNA high-throughput sequencing and short-chain fatty acid (SCFA) determination, we found that inhibition of the CB1 receptor increased the diversity of the microbial flora and controlled the makeup of intestinal flora. Moreover, butyric acid concentration and the amount of SCFA-producing bacteria, such as Ruminococcaceae and Lachnospiraceae, were both markedly elevated by CB1 receptor inhibition. The results of the spearman correlation study indicated that Lachnospiraceae showed a positive association with both ZO-1 and Occludin but was negatively correlated with the colon CB1 receptor, IL-1ß, and TNF-α. According to this study, we found that inhibiting CB1 receptor can improve CIH-induced colon injury by regulating gut microbiota, reducing mucosal damage and promoting tight junction recovery. KEY POINTS: â¢CIH leads to overexpression of CB1 receptor in colon tissue. â¢CIH causes intestinal flora disorder, intestinal mucosal damage, and disruption of tight junctions. â¢Inhibition of CB1 receptor can alleviate the colon injury caused by CIH through regulating the gut microbiota, reducing mucosal injury, and promoting tight junction recovery.
Assuntos
Colo , Modelos Animais de Doenças , Mucosa Intestinal , Receptor CB1 de Canabinoide , Animais , Receptor CB1 de Canabinoide/metabolismo , Receptor CB1 de Canabinoide/genética , Camundongos , Colo/patologia , Colo/microbiologia , Colo/metabolismo , Masculino , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Hipóxia/metabolismo , Camundongos Endogâmicos C57BL , Proteína da Zônula de Oclusão-1/metabolismo , Ocludina/metabolismo , Ocludina/genética , Microbioma Gastrointestinal , Junções Íntimas/metabolismoRESUMO
Mogroside, the main component of Siraitia grosvenorii (Swingle) C. Jeffrey (Cucurbitaceae) is a natural product with hypoglycemic and intestinal microbiota regulating properties. However, whether the alteration of intestinal microbiota is associated with the antidiabetic effect of mogroside remains poorly understood. This study investigated the mechanism underlying the hypoglycemic effect of mogroside in regulating intestinal flora and attenuating metabolic endotoxemia. Kunming mice with type 2 diabetes mellitus (T2DM) induced by high-fat diet and intraperitoneal injection of streptozotocin were randomly divided into model, pioglitazone (2.57 mg/kg) and mogroside (200, 100, and 50 mg/kg) groups. After 28 d of administration, molecular changes related to glucose metabolism and metabolic endotoxemia in mice were evaluated. The levels of insulin receptor substrate-1 (IRS-1), cluster of differentiation 14 (CD14) and toll-like receptor 4 (TLR4) mRNAs were measured, and the composition of intestinal microflora was determined by 16s ribosomal DNA (rDNA) sequencing. The results showed that mogroside treatment significantly improved hepatic glucose metabolism in T2DM mice. More importantly, mogroside treatment considerably reduced plasma endotoxin (inhibition rate 65.93%, high-dose group) and inflammatory factor levels, with a concomitant decrease in CD14 and TLR4 mRNA levels. Moreover, mogroside treatment reduced the relative abundance of Firmicutes and Proteobacteria (the inhibition rate of Proteobacteria was 85.17% in the low-dose group) and increased the relative abundance of Bacteroidetes (growth rate up to 40.57%, high-dose group) in the intestines of diabetic mice. This study reveals that mogroside can relieve T2DM, regulating intestinal flora and improving intestinal mucosal barrier, indicating that mogroside can be a potential therapeutic agent or intestinal microbiota regulator in the treatment of T2DM.
Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Microbioma Gastrointestinal , Hipoglicemiantes , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/microbiologia , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/sangue , Camundongos , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Dieta Hiperlipídica/efeitos adversos , Glicemia/efeitos dos fármacos , Triterpenos/farmacologia , Triterpenos/uso terapêutico , Receptor 4 Toll-Like/metabolismo , Endotoxemia/tratamento farmacológico , Fígado/efeitos dos fármacos , Fígado/metabolismoRESUMO
Dual specificity phosphatase 1 (DUSP1) and valosin-containing protein (VCP) have both been reported to regulate mitochondrial homeostasis. However, their impact on mitochondrial quality control (MQC) and myocardial function during LPS-induced endotoxemia remains unclear. We addressed this issue by modeling LPS-induced endotoxemia in DUSP1 transgenic (DUSP1TG) mice and in cultured DUSP1-overexpressing HL-1 cardiomyocytes. Accompanying characteristic structural and functional deficits, cardiac DUSP1 expression was significantly downregulated following endotoxemia induction in wild type mice. In contrast, markedly reduced myocardial inflammation, cardiomyocyte apoptosis, cardiac structural disorder, cardiac injury marker levels, and normalized systolic/diastolic function were observed in DUSP1TG mice. Furthermore, DUSP1 overexpression in HL-1 cells significantly attenuated LPS-mediated mitochondrial dysfunction by preserving MQC, as indicated by normalized mitochondrial dynamics, improved mitophagy, enhanced biogenesis, and attenuated mitochondrial unfolded protein response. Molecular assays showed that VCP was a substrate of DUSP1 and the interaction between DUSP1 and VCP primarily occurred on the mitochondria. Mechanistically, DUSP1 phosphatase domain promoted the physiological DUSP1/VCP interaction which prevented LPS-mediated VCP Ser784 phosphorylation. Accordingly, transfection with a phosphomimetic VCP mutant abolished the protective actions of DUSP1 on MQC and aggravated inflammation, apoptosis, and contractility/relaxation capacity in HL-1 cardiomyocytes. These findings support the involvement of the novel DUSP1/VCP/MQC pathway in the pathogenesis of endotoxemia-caused myocardial dysfunction.