Toll-like receptors in ischemia-reperfusion injury. Shock. 2009;32:4-16. [PMID: 19008778 DOI: 10.1097/shk.0b013e318193e333]

Modulation of the Oxidative Stress and ICAM-1/TLR4/NF-Κβ Levels by Metformin in Intestinal Ischemia/Reperfusion Injury in Rats

Metformin, a biguanide drug, is used for its antihyperglycemic effects. The purpose of the present study was to investigate the effects of metformin on the experimental model of intestinal ischemia-reperfusion (I/R) injury. Ischemia was induced by superior mesenteric artery occlusion followed by reperfusion. Metformin was administered orally by gavage at doses of 50, 100 or 200 mg/kg for one week before the surgery. Rats were divided to five groups (n = 8 for each): Sham control group; I/R control group; Metformin50 treated I/R group; Metformin100 treated I/R group; and Metformin200 treated I/R group. Tissue levels of malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO) activity, intercellular adhesion molecule-1 (ICAM-1), toll-like receptor 4 (TLR4), and nuclear factor-κB (NF-κB) as well as histological analysis were evaluated. Metformin treatment decreased the levels of MDA in 100 and 200 mg/kg doses besides lowering the MPO activity and ICAM-1 levels in all doses. Metformin also reduced NF-κB levels at dose of 200 mg/kg and improved histopathological scores at doses of 100 and 200 mg/kg. The treatment with metformin can prevent I/R-induced intestinal injury through down-regulating ICAM-1 and NF-κB levels, reducing oxidative stress, and lowering neutrophil accumulation. We propose that metformin could be a therapeutic agent in intestinal I/R.

TLR4 signalling in ischemia/reperfusion injury: a promising target for linking inflammation, oxidative stress and programmed cell death to improve organ transplantation outcomes

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.

Ischemic stroke and diabetes: a TLR4-mediated neuroinflammatory perspective

Ischemic stroke is the major contributor to morbidity and mortality in people with diabetes mellitus. In ischemic stroke patients, neuroinflammation is now understood to be one of the main underlying mechanisms for cerebral damage and recovery delay. It has been well-established that toll-like receptor 4 (TLR4) signaling pathway plays a key role in neuroinflammation. Emerging research over the last decade has revealed that, compared to ischemic stroke without diabetes mellitus, ischemic stroke with diabetes mellitus significantly upregulates TLR4-mediated neuroinflammation, increasing the risk of cerebral and neuronal damage as well as neurofunctional recovery delay. This review aims to discuss how ischemic stroke with diabetes mellitus amplifies TLR4-mediated neuroinflammation and its consequences. Additionally covered in this review is the potential application of TLR4 antagonists in the management of diabetic ischemic stroke.

HMGN1 down-regulation in the diabetic kidney attenuates tubular cells injury and protects against renal inflammation via suppressing MCP-1 and KIM-1 expression through TLR4

BACKGROUND

Renal tubular injury, accompanied by damaging inflammation, has been identified to drive diabetic kidney disease (DKD) toward end-stage renal disease. However, it is unclear how damage-associated molecular patterns (DAMPs) activate innate immunity to mediate tubular epithelial cell (TEC) injury, which in turn causes with subsequent sterile inflammation in diabetic kidneys. High mobility group nucleosome-binding protein 1 (HMGN1) is a novel DAMP that contributes to generating the innate immune response. In this study, we focused on determining whether HMGN1 is involved in DKD progression.

METHODS

Streptozotocin (STZ)-induced diabetic mice model was established. Then we downrergulated HMGN1 expression in kidney with or without HMGN1 administration. The renal dysfunction and morphological lesions in the kidneys were evaluated. The expressions of KIM-1, MCP-1, F4/80, CD68, and HMGN1/TLR4 signaling were examined in the renal tissue. In vitro, HK2 cells were exposed in the high glucose with or without HMGN1, and further pre-incubated with TAK242 was applied to elucidate the underlying mechanism.

RESULTS

We demonstrated that HMGN1 was upregulated in the tubular epithelial cells of streptozotocin (STZ)-induced type 1 and type 2 diabetic mouse kidneys compared to controls, while being positively correlated with increased TLR4, KIM-1, and MCP-1. Down-regulation of renal HMGN1 attenuated diabetic kidney injury, decreased the TLR4, KIM-1, and MCP-1 expression levels, and reduced interstitial infiltrating macrophages. However, these phenotypes were reversed after administration of HMGN1. In HK-2 cells, HMGN1 promoted the expression of KIM-1 and MCP-1 via regulating MyD88/NF-κB pathway; inhibition of TLR4 effectively diminished the in vitro response to HMGN1.

CONCLUSIONS

Our study provides novel insight into HMGN1 signaling mechanisms that contribute to tubular sterile injury and low-grade inflammation in DKD. The study findings may help to develop new HMGN1-targeted approaches as therapy for immune-mediated kidney damage rather than as an anti-infection treatments.

The association between serum heat shock protein 72 and intestinal permeability with intestinal microbiota and clinical severity in patients with cerebral infarction

Objectives

We aimed to compare serum heat shock protein 72 (HSP72) and intestinal permeability in patients with cerebral infarction (CI) and healthy individuals to reveal their correlations and link to gut microbiota alterations and clinical severity of CI.

Methods and results

Stool samples of 50 patients with CI and 46 healthy volunteers were analyzed through 16S rRNA gene sequencing to characterize intestinal flora profiles. Serum HSP72 and zonulin were assayed using enzyme-linked immunoassay (ELISA). The obtained data were then subjected to comparative and correlative analysis. We found that the levels of zonulin and serum HSP72 were significantly higher in the CI group compared to the healthy group. Serum HSP72 and zonulin levels were positively correlated in the CI group and correlated positively with the clinical severity of CI. β diversity showed significant differences in intestinal microbiota composition between the two groups. In the CI patient group, the abundance of bacteria Eubacterium_fissicatena_group, Eubacterium_eligens_group, and Romboutsia manifested a remarkably positive correlation with serum HSP72. The abundance of bacteria Eubacterium_fissicatena_group and Acetivibrio had a significantly positive correlation with zonulin levels.

Conclusion

Our findings indicated that an increase in serum HSP72 and zonulin levels was manifested in patients with CI and was related to specific gut microbiota alterations and the clinical severity of CI.

Therapeutic Correlation of TLR-4 Mediated NF-κB Inflammatory Pathways in Ischemic Injuries

Ischemia-reperfusion (I/R) injury refers to the tissue damage that happens when blood flow returns to tissue after a period of ischemia. I/R injuries are implicated in a large array of pathological conditions, such as cerebral, myocardial, renal, intestinal, retinal and hepatic ischemia. The hallmark of these pathologies is excessive inflammation. Toll-like receptors (TLRs) are recognized as significant contributors to inflammation caused by pathogens and, more recently, inflammation caused by injury. TLR-4 activation initiates a series of events that results in activation of nuclear factor kappa-B (NF-κB), which stimulates the production of pro-inflammatory cytokines and chemokines, exacerbating tissue injury. Therefore, through a comprehensive review of current research and experimentation, this investigation elucidates the TLRs signalling pathway and the role of TLR-4/NF-κB in the pathophysiology of I/R injuries. Furthermore, this review highlights the various pharmacological agents (TLR-4/NF-κB inhibitors) with special emphasis on the various ischemic injuries (cerebral, myocardial, renal, intestinal, retinal and hepatic). Future research should prioritise investigating the specific molecular pathways that cause TLR-4/NF-κBmediated inflammation in ischemic injuries. Additionally, efforts should be made to enhance treatment approaches in order to enhance patient outcomes.

Innate immune modulation in transplantation: mechanisms, challenges, and opportunities

Organ transplantation is characterized by a sequence of steps that involve operative trauma, organ preservation, and ischemia-reperfusion injury in the transplant recipient. During this process, the release of damage-associated molecular patterns (DAMPs) promotes the activation of innate immune cells via engagement of the toll-like receptor (TLR) system, the complement system, and coagulation cascade. Different classes of effector responses are then carried out by specialized populations of macrophages, dendritic cells, and T and B lymphocytes; these play a central role in the orchestration and regulation of the inflammatory response and modulation of the ensuing adaptive immune response to transplant allografts. Organ function and rejection of human allografts have traditionally been studied through the lens of adaptive immunity; however, an increasing body of work has provided a more comprehensive picture of the pivotal role of innate regulation of adaptive immune responses in transplant and the potential therapeutic implications. Herein we review literature that examines the repercussions of inflammatory injury to transplantable organs. We highlight novel concepts in the pathophysiology and mechanisms involved in innate control of adaptive immunity and rejection. Furthermore, we discuss existing evidence on novel therapies aimed at innate immunomodulation and how this could be harnessed in the transplant setting.

D-allose Inhibits TLR4/PI3K/AKT Signaling to Attenuate Neuroinflammation and Neuronal Apoptosis by Inhibiting Gal-3 Following Ischemic Stroke

BACKGROUND

Ischemic stroke (IS) occurs when a blood vessel supplying the brain becomes obstructed, resulting in cerebral ischemia. This type of stroke accounts for approximately 87% of all strokes. Globally, IS leads to high mortality and poor prognosis and is associated with neuroinflammation and neuronal apoptosis. D-allose is a bio-substrate of glucose that is widely expressed in many plants. Our previous study showed that D-allose exerted neuroprotective effects against acute cerebral ischemic/reperfusion (I/R) injury by reducing neuroinflammation. Here, we aimed to clarify the beneficial effects D-allose in suppressing IS-induced neuroinflammation damage, cytotoxicity, neuronal apoptosis and neurological deficits and the underlying mechanism in vitro and in vivo.

METHODS

In vivo, an I/R model was induced by middle cerebral artery occlusion and reperfusion (MCAO/R) in C57BL/6 N mice, and D-allose was given by intraperitoneal injection within 5 min after reperfusion. In vitro, mouse hippocampal neuronal cells (HT-22) with oxygen-glucose deprivation and reperfusion (OGD/R) were established as a cell model of IS. Neurological scores, some cytokines, cytotoxicity and apoptosis in the brain and cell lines were measured. Moreover, Gal-3 short hairpin RNAs, lentiviruses and adeno-associated viruses were used to modulate Gal-3 expression in neurons in vitro and in vivo to reveal the molecular mechanism.

RESULTS

D-allose alleviated cytotoxicity, including cell viability, LDH release and apoptosis, in HT-22 cells after OGD/R, which also alleviated brain injury, as indicated by lesion volume, brain edema, neuronal apoptosis, and neurological functional deficits, in a mouse model of I/R. Moreover, D-allose decreased the release of inflammatory factors, such as IL-1β, IL-6 and TNF-α. Furthermore, the expression of Gal-3 was increased by I/R in wild-type mice and HT-22 cells, and this factor further bound to TLR4, as confirmed by three-dimensional structure prediction and Co-IP. Silencing the Gal-3 gene with shRNAs decreased the activation of TLR4 signaling and alleviated IS-induced neuroinflammation, apoptosis and brain injury. Importantly, the loss of Gal-3 enhanced the D-allose-mediated protection against I/R-induced HT-22 cell injury, inflammatory insults and apoptosis, whereas activation of TLR4 by the selective agonist LPS increased the degree of neuronal injury and abolished the protective effects of D-allose.

CONCLUSIONS

In summary, D-allose plays a crucial role in inhibiting inflammation after IS by suppressing Gal-3/TLR4/PI3K/AKT signaling pathway in vitro and in vivo.

Dexmedetomidine against intestinal ischemia/reperfusion injury: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Intestinal ischemia/reperfusion injury (IRI) is a multifactorial, complex pathophysiological process in clinical settings. In recent years, intestinal IRI has received increasing attention due to increased morbidity and mortality. To date, there are no effective treatments. Dexmedetomidine (DEX), a highly selective α2-adrenergic receptor agonist, has been demonstrated to be effective against intestinal IRI. In this systematic review and meta-analysis, we evaluated the efficacy and potential mechanisms of DEX as a treatment for intestinal IRI in animal models.

METHODS

Five databases (PubMed, Embase, Web of Science, Cochrane Library, and Scopus) were searched until March 15, 2023. Using the SYRCLE risk bias tool, we assessed methodological quality. Statistical analysis was conducted using STATA 12 and R 4.2.2. We analyzed the related outcomes (mucosa damage-related indicators; inflammation-relevant markers, oxidative stress markers) relied on the fixed or random-effects models.

RESULTS

There were 15 articles including 18 studies included, and 309 animals were involved in the studies. Compared to the model groups, DEX improved intestinal IRI. DEX decreased Chiu's score and serum diamine oxidase (DAO) level. DEX reduced the level of inflammation-relevant markers (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α). DEX also improved oxidative stress (decreased malondialdehyde (MDA), increased superoxide dismutase (SOD)).

CONCLUSIONS

DEX's effectiveness in ameliorating intestinal IRI has been demonstrated in animal models. Antioxidation, anti-inflammation, anti-apoptotic, anti-pyroptosis, anti-ferroptosis, enhancing mitophagy, reshaping the gut microbiota, and gut barrier protection are possible mechanisms. However, in light of the heterogeneity and methodological quality of these studies, further well-designed preclinical studies are warranted before clinical implication.

Therapeutic Myogenesis Induced by Ultrasound Exposure in a Volumetric Skeletal Muscle Loss Injury Model

BACKGROUND

Low-intensity pulsed ultrasound (LIPUS) irradiation has been shown to induce various responses in different cells. It has been shown that LIPUS activates extracellular signal-regulated kinase 1/2 (ERK1/2) through integrin.

PURPOSE

To study the effects of LIPUS on myogenic regulatory factors and other related myogenesis elements in a volumetric skeletal muscle loss injury model.

STUDY DESIGN

Controlled laboratory study.

METHODS

C57BL/6J mice were subjected to full-thickness muscle defect injury of the quadriceps and treated with direct application of LIPUS 20 min/d or non-LIPUS treatment (control) for 3, 7, and 14 days. LIPUS was also applied to C2C12 cells in culture in the presence of low and high doses of lipopolysaccharides. The expression levels of myogenic regulatory factors and the expression levels of myokine-related and angiogenic-related proteins of the control and LIPUS groups were analyzed.

RESULTS

Muscle volume in the injury site was restored at day 14 with LIPUS treatment. Paired-box protein 7, myogenic factor 5, myogenin, and desmin expressions were significantly different between control and LIPUS groups at days 7 and 14. Myokine and angiogenic cytokine-related factors were significantly increased in the LIPUS group at day 3 and decreased with no significant difference between the groups by day 14. LIPUS induced different responses of myogenic regulatory factors in C2C12 cells with low and high doses of lipopolysaccharides. LIPUS promoted myogenesis through short-lived increase in interleukin-6 and heme oxygenase 1, together with activation of ERK1/2.

CONCLUSION

LIPUS had a constant effect on the variables of tissue damage, from macrotrauma to microtrauma, leading to efficient muscle regeneration.

CLINICAL RELEVANCE

The focus of therapeutic strategies with LIPUS has been not only for microvascular regeneration but also for skeletal muscle and related local tissue recovery from acute or chronic damage.

Interferon-β decreases LPS-induced neutrophil recruitment to cardiac fibroblasts

Introduction: Cardiac fibroblasts (CF) are crucial cells in damaged heart tissues, expressing TLR4, IFN-receptor and responding to lipopolysaccharide (LPS) and interferon-β (IFN-β) respectively. While CF interact with immune cells; however, their relationship with neutrophils remains understudied. Additionally, theimpact of LPS and IFN-β on CF-neutrophil interaction is poorly understood. Methods: Isolated CF from adult rats were treated with LPS, with or without IFN-β. This study examined IL-8 secretion, ICAM-1 and VCAM-1 expression, and neutrophil recruitment, as well as their effects on MMPs activity. Results: LPS triggered increased IL-8 expression and secretion, along with elevated ICAM-1 and VCAM-1 expression, all of which were blocked by TAK-242. Pre-treatment with IFN-β countered these LPS effects. LPS treated CF showed higher neutrophil recruitment (migration and adhesion) compared to unstimulated CF, an effect prevented by IFN-β. Ruxolitinib blocked these IFN-β anti-inflammatory effects, implicating JAK signaling. Analysis of culture medium zymograms from CF alone, and CF-neutrophils interaction, revealed that MMP2 was mainly originated from CF, while MMP9 could come from neutrophils. LPS and IFN-β boosted MMP2 secretion by CF. MMP9 activity in CF was low, and LPS or IFN-β had no significant impact. Pre-treating CF with LPS, IFN-β, or both before co-culture with neutrophils increased MMP2. Neutrophil co-culture increased MMP9 activity, with IFN-β pre-treatment reducing MMP9 compared to unstimulated CF. Conclusion: In CF, LPS induces the secretion of IL-8 favoring neutrophils recruitment and these effects were blocked by IFN-. The results highlight that CF-neutrophil interaction appears to influence the extracellular matrix through MMPs activity modulation.

Lactoferrin alleviates cyclophosphamide induced-nephropathy through suppressing the orchestration between Wnt4/β-catenin and ERK1/2/NF-κB signaling and modulating klotho and Nrf2/HO-1 pathway

AIMS

Cyclophosphamide is an alkylating agent with vast arrays of therapeutic activity. Currently, its medical use is limited due to its numerous adverse events, including nephrotoxicity. This study aimed to follow the molecular mechanisms behind the potential renoprotective action of lactoferrin (LF) against cyclophosphamide (CP)-induced renal injury.

MATERIALS AND METHODS

For fulfillment of our aim, Spragw-Dwaly rats were orally administrated LF (300 mg/kg) for seven consecutive days, followed by a single intraperitoneal injection of CP (150 mg/kg).

KEY FINDINGS

Treatment of CP-injured rats with LF significantly reduced the elevated creatinine and blood urea nitrogen (BUN), markedly upregulated Nrf2/HO-1 signaling with consequent increase in renal total antioxidant capacity (TAC) and decrease in renal malondialdehyde (MDA) level. Furthermore, LF treatment significantly reduced the elevated renal p-ERK1/2 expression, tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB) levels in CP-treated animals. Interestingly, LF treatment downregulated Wnt4/β-catenin signaling and increased both renal klotho gene expression and serum klotho level. Furthermore, LF treatment reduced apoptosis in kidney tissue via suppressing GSK-3β expression and modulating caspase-3 and Bcl2 levels. Histopathological examination of kidney tissue confirmed the protective effect of LF against CP-induced renal injury.

SIGNIFICANCE

The present findings document the renoprotective effect of LF against CP-induced nephropathy, which may be mediated via suppressing ERK1/2/ NF-κB and Wnt4/β-catenin trajectories and enhancing klotho expression and Nrf2/HO-1 signaling.

Narrative review of systemic inflammatory response mechanisms in cardiac surgery and immunomodulatory role of anesthetic agents

Although surgical techniques and perioperative care have made significant advances, perioperative mortality in cardiac surgery remains relatively high. Single- or multiple-organ failure remains the leading cause of postoperative mortality. Systemic inflammatory response syndrome (SIRS) is a common trigger for organ injury or dysfunction in surgical patients. Cardiac surgery involves major surgical dissection, the use of cardiopulmonary bypass (CPB), and frequent blood transfusions. Ischemia-reperfusion injury and contact activation from CPB are among the major triggers for SIRS. Blood transfusion can also induce proinflammatory responses. Here, we review the immunological mechanisms of organ injury and the role of anesthetic regimens in cardiac surgery.

Ginsenoside Rg1 attenuates cerebral ischemia-reperfusion injury through inhibiting the inflammatory activation of microglia

It is recognized that the cerebral ischemia/reperfusion (I/R) injury triggers inflammatory activation of microglia and supports microglia-driven neuronal damage. Our previous studies have shown that ginsenoside Rg1 had a significant protective effect on focal cerebral I/R injury in middle cerebral artery occlusion (MCAO) rats. However, the mechanism still needs further clarification. Here, we firstly reported that ginsenoside Rg1 effectively suppressed the inflammatory activation of brain microglia cells under I/R conditions depending on the inhibition of Toll-likereceptor4 (TLR4) proteins. In vivo experiments showed that the ginsenoside Rg1 administration could significantly improve the cognitive function of MCAO rats, and in vitro experimental data showed that ginsenoside Rg1 significantly alleviated neuronal damage via inhibiting the inflammatory response in microglia cells co-cultured under oxygen and glucose deprivation/reoxygenation (OGD/R) condition in gradient dependent. The mechanism study showed that the effect of ginsenoside Rg1 depends on the suppression of TLR4/MyD88/NF-κB and TLR4/TRIF/IRF-3 pathways in microglia cells. In a word, our research shows that ginsenoside Rg1 has great application potential in attenuating the cerebral I/R injury by targeting TLR4 protein in the microglia cells.

Immunoregulatory mechanism of acute kidney injury in sepsis: A Narrative Review

Sepsis acute kidney injury (SAKI) is a common complication of sepsis, accounting for 26-50 % of all acute kidney injury (AKI). AKI is an independent risk factor for increased mortality risk in patients with sepsis. The excessive inflammatory cascade reaction in SAKI is one of the main causes of kidney damage. Both the innate immune system and the adaptive immune system are involved in the inflammation process of SAKI. Under the action of endotoxin, neutrophils, monocytes, macrophages, T cells and other complex immune network reactions occur, and a large number of endogenous inflammatory mediators are released, resulting in the amplification and loss of control of the inflammatory response. The study of immune cells in SAKI will help improve the understanding of the immune mechanisms of SAKI, and will lay a foundation for the development of new diagnostic and therapeutic targets. This article reviews the role of known immune mechanisms in the occurrence and development of SAKI, with a view to finding new targets for SAKI treatment.

CD36 neutralisation blunts TLR2-IRF7 but not IRF3 pathway in neonatal mouse brain and immature human microglia following innate immune challenge

Innate immune response in neonatal brain is associated with a robust microglial activation and induction of Toll-like Receptors (TLRs). To date, the role of the scavenger receptor CD36 in TLRs modulation, particularly TLR2 signaling, has been well established in adult brain. However, the crosstalk between TLR4, TLR2 and CD36 and its immunogenic influence in the neonatal brain remains unclear. In this study, using a CD36 blocking antibody (anti-CD36) at post-natal day 8, we evaluated the response of neonates to systemic endotoxin (lipopolysaccharide; LPS) challenge. We visualized the TLR2 response by bioluminescence imaging using the transgenic mouse model bearing the dual reporter system luciferase/green fluorescent protein under transcriptional control of a murine TLR2 promoter. The anti-CD36 treatment modified the LPS induced inflammatory profile in neonatal brains, causing a significant decrease in inflammatory cytokine levels and the TLR2 and TLR3 mediated signalling.The interferon regulatory factor 3 (IRF3) pathway remained unaffected. Treatment of the LPS-challenged human immature microglia with anti-CD36 induced a marked decrease in TLR2/TLR3 expression levels while TLR4 and IRF3 expression was not affected, suggesting the shared CD36 regulatory mechanisms in human and mouse microglia. Collectively, our results indicate that blocking CD36 alters LPS-induced inflammatory profile of mouse and human microglia, suggesting its role in fine-tuning of neuroinflammation.

Toll-like receptor-2 in cardiomyocytes and macrophages mediates isoproterenol-induced cardiac inflammation and remodeling

Heart failure (HF) is the leading cause of morbidity and mortality worldwide. Activation of the innate immune system initiates an inflammatory response during cardiac remodeling induced by isoproterenol (ISO). Here, we investigated whether Toll-like receptor-2 (TLR2) mediates ISO-induced inflammation, hypertrophy, and fibrosis. TLR2 was found to be increased in the heart tissues of mouse with HF under ISO challenge. Further, cardiomyocytes and macrophages were identified as the main cellular sources of the increased TLR2 levels in the model under ISO stimulation. The effect of TLR2 deficiency on ISO-induced cardiac remodeling was determined using TLR2 knockout mice and bone marrow transplantation models. In vitro studies involving ISO-treated cultured cardiomyocytes and macrophages showed that TLR2 knockdown significantly decreased ISO-induced cell inflammation and remodeling via MAPKs/NF-κB signaling. Mechanistically, ISO significantly increased the TLR2-MyD88 interaction in the above cells in a TLR1-dependent manner. Finally, DAMPs, such as HSP70 and fibronectin 1 (FN1), were found to be released from the cells under ISO stimulation, which further activated TLR1/2-Myd88 signaling and subsequently activated pro-inflammatory cytokine expression and cardiac remodeling. In summary, our findings suggest that TLR2 may be a target for the alleviation of chronic adrenergic stimulation-associated HF. In addition, this paper points out the possibility of TLR2 as a new target for heart failure under ISO stimulation.

Neonatal asphyxia as an inflammatory disease: Reactive oxygen species and cytokines

Neonatologists resuscitate asphyxiated neonates by every available means, including positive ventilation, oxygen therapy, and drugs. Asphyxiated neonates sometimes present symptoms that mimic those of inflammation, such as fever and edema. The main pathophysiology of the asphyxia is inflammation caused by hypoxic-ischemic reperfusion. At birth or in the perinatal period, neonates may suffer several, hypoxic insults, which can activate inflammatory cells and inflammatory mediator production leading to the release of larger quantities of reactive oxygen species (ROS). This in turn triggers the production of oxygen stress-induced high mobility group box-1 (HMGB-1), an endogenous damage-associated molecular patterns (DAMPs) protein bound to toll-like receptor (TLR) -4, which activates nuclear factor-kappa B (NF-κB), resulting in the production of excess inflammatory mediators. ROS and inflammatory mediators are produced not only in activated inflammatory cells but also in non-immune cells, such as endothelial cells. Hypothermia inhibits pro-inflammatory mediators. A combination therapy of hypothermia and medications, such as erythropoietin and melatonin, is attracting attention now. These medications have both anti-oxidant and anti-inflammatory effects. As the inflammatory response and oxidative stress play a critical role in the pathophysiology of neonatal asphyxia, these drugs may contribute to improving patient outcomes.

Sevoflurane postconditioning ameliorates cerebral ischemia-reperfusion injury in rats via TLR4/MyD88/TRAF6 signaling pathway

To determine whether sevoflurane postconditioning protects against cerebral ischemia reperfusion (I/R) injury and its potential mechanism, we employed bioinformatic analysis, neurological assessments, and western blot analysis, as well as triphenyl tetrazolium chloride, hematoxylin and eosin, Nissl, and immunofluorescence staining. We identified 103 differentially expressed genes induced by cerebral I/R, including 75 upregulated genes and 28 downregulated genes enriched for certain biological processes (involving regulation of inflammatory responses, cellular responses to interleukin 1, and chemokine activity) and signaling pathways (such as transcriptional misregulation in cancer, interleukin-17 signaling, rheumatoid arthritis, MAPK signaling, and Toll-like receptor signaling). As a typical path in Toll-like receptor signaling pathway, in the current study, we investigated the protective effect of sevoflurane postconditioning in cerebral I/R rats and further explore the role of TLR4/MyD88/TRAF6 signaling pathway in it. The results showed cerebral I/R-induced neurological deficits were comparatively less severe following sevoflurane postconditioning. In addition, TLR4/MyD88/TRAF6 signaling pathway-related proteins and neuropathic damage were ameliorated in aged rats following sevoflurane postconditioning, while the TLR4 agonist lipopolysaccharide aggravated these changes. Together, these findings suggest that sevoflurane postconditioning ameliorates cerebral I/R injury by a mechanism involving inhibition of the TLR4/MyD88/TRAF6 signaling pathway to suppress neuroinflammatory responses.

Luteolin alleviates inflammation and autophagy of hippocampus induced by cerebral ischemia/reperfusion by activating PPAR gamma in rats

Background

Luteolin, a flavonoid compound with anti-inflammatory activity, has been reported to alleviate cerebral ischemia/reperfusion (I/R) injury. However, its potential mechanism remains unclear.

Methods

The binding activity of luteolin to peroxisome proliferator-activated receptor gamma (PPARγ) was calculated via molecular docking analysis. Rats were subjected to middle cerebral artery occlusion and reperfusion (MCAO/R). After reperfusion, vehicle, 25 mg/kg/d luteolin, 50 mg/kg/d luteolin, 10 mg/kg/d pioglitazone, 50 mg/kg/d luteolin combined with 10 mg/kg/d T0070907 (PPARγ inhibitor) were immediately orally treatment for 7 days. ELISA, TTC staining, H&E staining, immunohistochemistry, immunofluorescence and transmission electron microscope methods were performed to evaluate the inflammation and autophagy in damaged hippocampal region. The PPARγ, light chain 3 (LC3) B-II/LC3B-I and p-nuclear factor-κB (NF-κB) p65 proteins expression levels in damaged hippocampal region were analyzed.

Results

Luteolin showed good PPARγ activity according to docking score (score = − 8.2). Luteolin treatment downregulated the infarct area and the pro-inflammatory cytokines levels caused by MCAO/R injury. Moreover, luteolin administration ameliorated neuroinflammation and autophagy in damaged hippocampal region. Pioglitazone plays protective roles similar to luteolin. T0070907 concealed the neuroprotective roles of 50 mg/kg/d luteolin.

Conclusions

Luteolin exerts neuroprotective roles against inflammation and autophagy of hippocampus induced by cerebral I/R by activating PPARγ in rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03652-8.

Argon preconditioning protects neuronal cells with a Toll-like receptor-mediated effect

The noble gas argon has the potential to protect neuronal cells from cell death. So far, this effect has been studied in treatment after acute damage. Preconditioning using argon has not yet been investigated. In this study, human neuroblastoma SH-SY5Y cells were treated with different concentrations of argon (25%, 50%, and 74%; 21% O₂, 5% CO₂, balance nitrogen) at different time intervals before inflicting damage with rotenone (20 µM, 4 hours). Apoptosis was determined by flow cytometry after annexin V and propidium iodide staining. Surface expressions of Toll-like receptors 2 and 4 were also examined. Cells were also processed for analysis by western blot and qPCR to determine the expression of apoptotic and inflammatory proteins, such as extracellular-signal regulated kinase (ERK1/2), nuclear transcription factor-κB (NF-κB), protein kinase B (Akt), caspase-3, Bax, Bcl-2, interleukin-8, and heat shock proteins. Immunohistochemical staining was performed for TLR2 and 4 and interleukin-8. Cells were also pretreated with OxPAPC, an antagonist of TLR2 and 4 to elucidate the molecular mechanism. Results showed that argon preconditioning before rotenone application caused a dose-dependent but not a time-dependent reduction in the number of apoptotic cells. Preconditioning with 74% argon for 2 hours was used for further experiments showing the most promising results. Argon decreased the surface expression of TLR2 and 4, whereas OxPAPC treatment partially abolished the protective effect of argon. Argon increased phosphorylation of ERK1/2 but decreased NF-κB and Akt. Preconditioning inhibited mitochondrial apoptosis and the heat shock response. Argon also suppressed the expression of the pro-inflammatory cytokine interleukin-8. Immunohistochemistry confirmed the alteration of TLRs and interleukin-8. OxPAPC reversed the argon effect on ERK1/2, Bax, Bcl-2, caspase-3, and interleukin-8 expression, but not on NF-κB and the heat shock proteins. Taken together, argon preconditioning protects against apoptosis of neuronal cells and mediates its action via Toll-like receptors. Argon may represent a promising therapeutic alternative in various clinical settings, such as the treatment of stroke.

Ameliorative Effect of D-Carvone against Hepatic Ischemia-Reperfusion-Induced Injury in Rats

BACKGROUND

D-carvone is a monoterpene that exists in the essential oils of several plant species. Hepatic ischemia-reperfusion (Hep I/R) takes place clinically during different scenarios of liver pathologies. The aim of the current investigation is to disclose the hepato-protective actions of carvone against Hep I/R-induced damage and to reveal the underlying mechanism.

MATERIAL AND METHODS

Rats were assigned into five groups: sham and carvone plus sham groups, in which rats were administered either saline or carvone orally for three weeks prior to the induction of Hep I/R. In the Hep I/R group, rats were administered saline orally prior to the Hep I/R induction operation. The carvone 25 plus Hep I/R and Carvone 50 plus Hep I/R groups were administered carvone (25 and 50 mg/kg, respectively) for three weeks, followed by the induction of Hep I/R.

RESULTS

Liver ischemic animals demonstrated impaired liver function, several histopathological variations, and reduced levels of antioxidant enzyme activities. Furthermore, the Hep I/R groups showed the elevated gene expression of high-mobility group box 1 (HMGB1), toll-like receptors 4 (TLR4), nuclear factor kappa B (NFκB), and LR family pyrin domain containing 3 (NLP3), with subsequent escalated adhesion molecule 1 (ICAM-1), neutrophil infiltration, and several inflammatory mediators, including interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α), as well as apoptotic markers. Pretreatment with D-carvone alleviated ischemia/reperfusion-induced impaired liver function, diminished the histopathological deviations, and augmented the antioxidant enzymes. In addition, D-carvone mitigated the gene expression of HMGB1, TLR4, NFκB, and NLP3, with a subsequent reduction in ICAM-1, neutrophils infiltration, inflammatory mediators, and apoptotic markers.

CONCLUSION

Rats pretreated with D-carvone exhibited hepato-protective actions against Hep I/R-induced damage via the downregulation of HMGB1, TLR4, NFκB, NLP3, associated inflammatory mediators, and apoptotic markers.

Diacerein attenuate LPS-induced acute lung injury via inhibiting ER stress and apoptosis: Impact on the crosstalk between SphK1/S1P, TLR4/NFκB/STAT3, and NLRP3/IL-1β signaling pathways

AIMS

Acute lung injury (ALI) is a life-threatening clinical problem with high mortality rate and limited treatments or preventive options that represents a major challenge for clinicians. Diacerein (DIA) is a multi-target anthraquinone derivative with potent anti-inflammatory action. The aim of this study is to assess the protective effect of DIA and its potential molecular targets against lipopolysaccharide (LPS)-induced ALI in rats.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were orally administrated DIA (50 mg/kg) for 5 consecutive days followed by a single intraperitoneal injection of LPS (5mg/kg).

KEY FINDINGS

DIA mitigated oxidative lung injury in LPS-challenged rats via significantly decreasing lung wet/dry (W/D) ratio, inflammatory cells infiltration, and lipid peroxidation, with concomitant elevation in enzymatic and non-enzymatic antioxidant levels in lung tissue. Likewise, DIA alleviated endoplasmic reticulum stress and markedly halted inflammation triggered by LPS challenge in pulmonary tissue by suppressing NLRP3/IL-1β and TLR4/NF-κB signaling with parallel decrease in proinflammatory cytokine levels. Interestingly, DIA down regulated Sphk1/S1P axis, reduced GSK-3β and STAT3 proteins expression, and markedly decreased caspase-3 besides increasing Bcl-2 levels in lung tissue of LPS-challenged animals. These biochemical findings was simultaneously associated with marked improvement in histological alterations of lung tissue.

SIGNIFICANCE

These findings verify the protective effect of DIA against LPS-induced ALI through targeting oxidative stress, endoplasmic reticulum stress, and apoptosis. Importantly, DIA halted the hyperinflammatory state triggered by LPS via multi-faceted inhibitory effect on different signaling pathways, hence DIA could potentially reduce mortality in patients with ALI.

Post-Cardiac Arrest Syndrome Is Not Associated With an Early Bacterial Translocation

BACKGROUND

The aim of this study was to investigate bacterial translocation and its possible role in the development of post-resuscitation inflammatory response following Cardio-Pulmonary Resuscitation (CPR) after cardiac arrest.

METHODS

Munich female swine were employed for a model of cardiac arrest via application of electrical current. After 7 min, CPR was initiated, and animals were either successfully return to spontaneous circulation (ROSC) within 40 min or not (no-ROSC). At the end of experimental period and prior to sacrifice, samples from the intestine, mesenteric lymph nodes (MLN), liver and portal vein blood were obtained. Evaluation of inflammation and gut permeability was performed; MLN, liver and portal vein samples were analyzed for 16 s rRNA detection and cytokine mRNA expression.

RESULTS

A decreased expression of the tight junction protein Occludin, with higher levels of inflammation, greater epithelial disintegration, ulceration, loss of crypts and villi height were found in the intestines of the ROSC swine in comparison to no-ROSC. The macrophage surface antigen CD-14 staining was relatively more intense in the ROSC than in no-ROSC. Higher levels of TNF-α mRNA expression were present in the liver of the ROSC group. Finally, despite the inflammatory response and the gut mucosal alterations in ROSC group, no bacterial translocation was detected in liver, MLN and portal vein.

CONCLUSIONS

We show that resuscitation from cardiac arrest induces inflammatory response and intestinal permeability in swine 4h after resuscitation, but not a bacterial translocation. Bacterial translocation is not an early phase phenomenon but probably part of the pathophysiologic sequelae.

Somatostatin attenuates intestinal epithelial barrier injury during acute intestinal ischemia-reperfusion through Tollip/Myeloiddifferentiationfactor 88/Nuclear factor kappa-B signaling

In the process of ischemia-reperfusion injury, intestinal ischemia and inflammation interweave, leading to tissue damage or necrosis. However, oxygen radicals and inflammatory mediators produced after reperfusion cause tissue damage again, resulting in severe intestinal epithelial barrier dysfunction. The aim of this study was to determine the protective effect of somatostatin on intestinal epithelial barrier function during intestinal ischemia-reperfusion injury and explore its mechanism. By establishing a rat intestinal ischemia-reperfusion model, pretreating the rats with somatostatin, and then detecting the histopathological changes, intestinal permeability and expression of tight junction proteins in intestinal tissues, the protective effect of somatostatin on the intestinal epithelial barrier was measured in vivo. The mechanism was determined in interferon γ (IFN-γ)-treated Caco-2 cells in vitro. The results showed that somatostatin could ameliorate ischemia-reperfusion-induced intestinal epithelial barrier dysfunction and protect Caco-2 cells against IFN-γ-induced decreases in tight junction protein expression and increases in monolayer cell permeability. The expression of Tollip was upregulated by somatostatin both in ischemia-reperfusion rats and IFN-γ-treated Caco-2 cells, while the activation of TLR2/MyD88/NF-κB signaling was inhibited by somatostatin. Tollip inhibition reversed the protective effect of somatostatin on the intestinal epithelial barrier. In conclusion, somatostatin could attenuate ischemia-reperfusion-induced intestinal epithelial barrier injury by inhibiting the activation of TLR2/MyD88/NF-κB signaling through upregulation of Tollip.

Coding and long non-coding gene expression changes in the CNS traumatic injuries

Traumatic brain injury (TBI) and spinal cord injury (SCI) are two main central nervous system (CNS) traumas, caused by external physical insults. Both injuries have devastating effects on the quality of life, and there is no effective therapy at present. Notably, gene expression profiling using bulk RNA sequencing (RNA-Seq) and single-cell RNA-Seq (scRNA-Seq) have revealed significant changes in many coding and non-coding genes, as well as important pathways in SCI and TBI. Particularly, recent studies have revealed that long non-coding RNAs (lncRNAs) with lengths greater than 200 nucleotides and without protein-coding potential have tissue- and cell type-specific expression pattern and play critical roles in CNS injury by gain- and loss-of-function approaches. LncRNAs have been shown to regulate protein-coding genes or microRNAs (miRNAs) directly or indirectly, participating in processes including inflammation, glial activation, cell apoptosis, and vasculature events. Therefore, lncRNAs could serve as potential targets for the diagnosis, treatment, and prognosis of SCI and TBI. In this review, we highlight the recent progress in transcriptome studies of SCI and TBI and insights into molecular mechanisms.

Skullcapflavone II protects neuronal damage in cerebral ischemic rats via inhibiting NF-ĸB and promoting angiogenesis

BACKGROUND

Cerebral ischemia (CI) is considered as a main cause of cerebral stroke (CS) and poses significant risk to the mankind across the world. In the present study, we intended to investigate the protective effect of Skullcapflavone II (SCP) a flavonoid isolated from S. baicalensis on cerebral ischemia/reperfusion (I/R) injury.

METHODS

The middle cerebral artery occlusion (MCAO) and reperfusion was used to create ischemic stroke rat model. The rats were treated with (5, 10, and 15 mg/kg) SCP and after the end of the experiment the rats were sacrificed and various biochemical parameters were assed to determine the pharmacological action of SCP.

RESULTS

SCP dramatically decreases cerebral edema, infarct volume, and improves neurological manifestation as confirmed by reduced neurological deficit. SCP also improves the survivability of neurons as evidenced by H and E and Nissl staining. The level of oxidative stress in the cerebral cortex of the rats was found reduced after treatment with SCP, as confirmed by increase in GSH and SOD activity with reduction in MDA content. In addition, SCP attenuated inflammation via reducing the level of TNF-α, IL-1β and IL-6 in brain tissues of rats. SCP increases the expression of Bcl2, cleaved caspase-3 and -9, while decreasing Bax, and NF-ĸB/TLR4. It causes induction of angiogenesis as suggested by increased expression of VEGF, Ang-1 and Tie-2 in cerebral cortex of rat.

CONCLUSIONS

Our data determined that SCP may provide protective effect on the I/R-induced cerebral ischemia.

Colchicine attenuates renal ischemia-reperfusion-induced liver damage: implication of TLR4/NF-κB, TGF-β, and BAX and Bcl-2 gene expression

Ischemia-reperfusion injury (IRI) is typically associated with a vigorous inflammatory and oxidative stress response to hypoxia and reperfusion that disturbs the function of the organ. The remote effects of renal IRI on the liver, however, require further study. Renal damage associated with liver disease is a common clinical problem. Colchicine, a polymerization inhibitor of microtubules, has been used as an anti-inflammatory and anti-fibrotic drug for liver diseases. The goal of the current study was to investigate the possible protective mechanisms of colchicine on liver injury following renal IRI. Forty rats were divided randomly into four groups: sham group, colchicine-treated group, IRI group, and colchicine-treated + IRI group. Treatment with colchicine significantly reduced hepatic toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB) transcription factor, myeloid differentiation factor 88 (MyD88), and tumor necrosis factor-alpha (TNF-α) contents; downregulated BCL2 associated X apoptosis regulator (BAX) gene expression, transforming growth factor-β (TGF-β) content, and upregulated hepatic B cell lymphoma 2 (Bcl-2) gene expression as compared with the IRI group. Finally, hepatic histopathological examinations have confirmed the biochemical results. Renal IRI-induced liver damage in rats was alleviated by colchicine through its anti-inflammatory, anti-apoptotic, and anti-fibrotic actions.

Effects of Adipose-Derived Biogenic Nanoparticle-Associated microRNA-451a on Toll-like Receptor 4-Induced Cytokines

Extracellular vesicles (EVs) are cell-released nanoparticles that transfer biomolecular content between cells. Among EV-associated biomolecules, microRNAs (miRNAs/miRs) represent one of the most important modulators of signaling pathways in recipient cells. Previous studies have shown that EVs from adipose-derived mesenchymal stromal cells (MSCs) and adipose tissue modulate inflammatory pathways in macrophages. In this study, the effects of miRNAs that are abundant in adipose tissue EVs and other biogenic nanoparticles (BiNPs) were assessed in terms of altering Toll-like receptor 4 (TLR4)-induced cytokines. TLR-4 signaling in macrophages is often triggered by pathogen or damage-induced inflammation and is associated with several diseases. This study demonstrates that miR-451a, which is abundant in adipose tissue BiNPs, suppresses pro-inflammatory cytokines and increases anti-inflammatory cytokines associated with the TLR4 pathway. Therefore, miR-451a may be partially responsible for immunomodulatory effects of adipose tissue-derived BiNPs.

Discovery of novel Ketamine-inspired derivatives as a protective agent against renal ischemic/reperfusion injury in Wistar rats

Renal ischemia-reperfusion (I/R) injury is a limiting factor for the success of renal grafts and is deemed greatly responsible for the mortality. A novel series of Ketamine inspired compounds were synthesized and subjected to NF-ĸB transcriptional inhibitory activity in LPS-stimulated RAW264.7 cells, where entire set of compounds showed mild to significant NF-ĸB transcriptional inhibitory activity (IC₅₀ 6.53 - 67.52 µM). Compound 6d showed highest inhibitory activity among the tested series (IC₅₀ 2.62 µM), and found more potent as compared to Ketamine as standard. The effect of compound 6d was further quantified in I/R injury in Wistar rats, where it dose-dependently improves kidney function of rats with significant amelioration of kidney injury as suggested by histopathological examination of renal tissues. It further showed reduction in the generation of pro-inflammatory cytokines and improves the anti-oxidant status of experimental rats. Compound 6d inhibited apoptosis and increases the expression of Bcl2 and decreases Bax, and cleaved caspase-3 level. It further reduces TLR-4 and NF-κB expression in renal cells of rats, with increases in IκB-α level in western blot analysis as compared to I/R group. In summary, our current study showed the development of a novel class of Ketamine-inspired derivatives against renal ischemia/reperfusion injury.

KDM2B overexpression prevents myocardial ischemia‑reperfusion injury in rats through regulating inflammatory response via the TLR4/NF‑κB p65 axis

Histone modifier lysine-specific demethylase 2B (KDM2B) has been previously reported to activate the inflammatory response by transcription initiation of the IL-6 gene. However, the effects of KDM2B on the inflammatory response during myocardial ischemia-reperfusion (I/R) injury and corresponding mechanisms remain poorly understood. The present study aimed to investigate the role and mechanism of KDM2B in myocardial I/R injury. Therefore, a myocardial I/R injury model was established in rats through coronary artery ligation. Adeno-associated virus-encoding KDM2B and small interfering RNA-KDM2B were designed to determine the effects of KDM2B on myocardial I/R injury using H&E staining and a TUNEL assay in the myocardial tissues. Reverse transcription-quantitative PCR and western blotting were performed to detect the mRNA and protein expression levels of KDM2B, toll-like receptor 4 (TLR4), NF-κB p65 and NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3). ELISA was used to detect the levels of TNF-α, IL-6 and IL-1β in the peripheral blood samples. Pathological analysis demonstrated that the cells in the model group were disordered, with a large area of necrosis and neutrophil infiltration. Knocking down KDM2B expression significantly upregulated the mRNA and protein expression levels of TLR4, NLRP3, NF-κB p65 and the ratio of phosphorylated (p)-p65 to p65. KDM2B knockdown also significantly increased the levels of IL-1β, IL-6 and TNF-α in the peripheral blood, which aggravated myocardial injury and promoted the apoptosis of myocardial cells. However, overexpression of KDM2B downregulated the mRNA and protein expression levels of TLR4, NLRP3, NF-κB P65, the ratio of p-p65 to p65 whilst reducing the levels of IL-1β, IL-6 and TNF-α in the peripheral blood, which markedly improved myocardial injury and significantly inhibited the apoptosis of cells in myocardial tissue. In conclusion, the results indicated that overexpression of KDM2B may prevent myocardial I/R injury in rats by reducing the inflammatory response through regulation of the TLR4/NF-κB p65 axis.

Innate Immunity as an Executor of the Programmed Death of Individual Organisms for the Benefit of the Entire Population

In humans, over-activation of innate immunity in response to viral or bacterial infections often causes severe illness and death. Furthermore, similar mechanisms related to innate immunity can cause pathogenesis and death in sepsis, massive trauma (including surgery and burns), ischemia/reperfusion, some toxic lesions, and viral infections including COVID-19. Based on the reviewed observations, we suggest that such severe outcomes may be manifestations of a controlled suicidal strategy protecting the entire population from the spread of pathogens and from dangerous pathologies rather than an aberrant hyperstimulation of defense responses. We argue that innate immunity may be involved in the implementation of an altruistic programmed death of an organism aimed at increasing the well-being of the whole community. We discuss possible ways to suppress this atavistic program by interfering with innate immunity and suggest that combating this program should be a major goal of future medicine.

Anesthetics mediated the immunomodulatory effects via regulation of TLR signaling

Anesthetics have been widely used in surgery and found to suppress inflammatory injury and affect the outcomes of the surgery and diseases. In contrast, anesthetics are also found to induce neuronal injury and inflammation. However, the immune-modulation mechanism of anesthetics is still not clear. Recent studies have shown that the immune-modulation of anesthetics is associated with the regulation of toll-like receptor (TLR)-mediated signaling. Moreover, the regulation of anesthetics in TLR signaling is related to modulations of non-coding RNAs (nc RNAs). Consistently, nc RNAs are mainly divided into micro RNAs (miRs) and long non-coding RNAs (lnc RNAs), which have been found to exert regulatory effects on the immune system. In this review, we summarize the immunomodulatory functions of the widely used anesthetic agents, which are associated with regulation of TLR signaling. In addition, we also focus on the roles of nc RNAs induced by anesthetics in regulations of TLR signaling.

Early Post-ischemic Brain Glucose Metabolism Is Dependent on Function of TLR2: a Study Using [18F]F-FDG PET-CT in a Mouse Model of Cardiac Arrest and Cardiopulmonary Resuscitation

Purpose

The mammalian brain glucose metabolism is tightly and sensitively regulated. An ischemic brain injury caused by cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) affects cerebral function and presumably also glucose metabolism. The majority of patients who survive CA suffer from cognitive deficits and physical disabilities. Toll-like receptor 2 (TLR2) plays a crucial role in inflammatory response in ischemia and reperfusion (I/R). Since deficiency of TLR2 was associated with increased survival after CA-CPR, in this study, glucose metabolism was measured using non-invasive [¹⁸F]F-FDG PET-CT imaging before and early after CA-CPR in a mouse model comparing wild-type (WT) and TLR2-deficient (TLR2^−/−) mice. The investigation will evaluate whether FDG-PET could be useful as an additional methodology in assessing prognosis.

Procedures

Two PET-CT scans using 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]F-FDG) tracer were carried out to measure dynamic glucose metabolism before and early after CPR. To achieve this, anesthetized and ventilated adult female WT and TLR2^−/− mice were scanned in PET-CT. After recovery from the baseline scan, the same animals underwent 10-min KCL-induced CA followed by CPR. Approximately 90 min after CA, measurements of [¹⁸F]F-FDG uptake for 60 min were started. The [¹⁸F]F-FDG standardized uptake values (SUVs) were calculated using PMOD-Software on fused FDG-PET-CT images with the included 3D Mirrione-Mouse-Brain-Atlas.

Results

The absolute SUV_mean of glucose in the whole brain of WT mice was increased about 25.6% after CA-CPR. In contrast, the absolute glucose SUV in the whole brain of TLR2^−/− mice was not significantly different between baseline and measurements post CA-CPR. In comparison, baseline measurements of both mouse strains show a highly significant difference with regard to the absolute glucose SUV in the whole brain. Values of TLR2^−/− mice revealed a 34.6% higher glucose uptake.

Conclusions

The altered mouse strains presented a different pattern in glucose uptake under normal and ischemic conditions, whereby the post-ischemic differences in glucose metabolism were associated with the function of key immune factor TLR2. There is evidence for using early FDG-PET-CT as an additional diagnostic tool after resuscitation. Further studies are needed to use PET-CT in predicting neurological outcomes.

Thrombosis in COVID-19 infection: Role of platelet activation-mediated immunity

Background

Thrombosis plays an important role in the Coronavrus Disease 2019 (COVID-19) infection-related complications such as acute respiratory distress syndrome and myocardial infarction. Multiple factors such as oxygen demand injuries, endothelial cells injury related to infection, and plaque formation.

Main body

Platelets obtained from the patients may have severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA, showing that the increased activation potential recommends platelet can be hyper-activated in severely ill SARS-CoV-2 cases. Platelets contain multiple receptors that interact with specific ligands. Pathogen’s receptors such as Toll-like receptors (TLRs), NOD-like receptor, C-type lectin receptor family, glycoprotein (GP) such as GPαIIbβ3 and GPIbα which allow pathogens to interact with platelets. Platelet TLRs and NOD2 are involved in platelet activation and thrombosis. Accordingly, TLRs are critical receptors that could recognize various endogenous damage-associated molecular patterns and exogenous pathogen-associated molecular patterns (PAMPs). TLRs are considered as important components in the activation of innate immunity response against pathogenic and non-pathogenic components like damaged tissues. TLRs-1,-2,-4,-6,-7 expression on or within platelets has been reported previously. Various PAMPs were indicated to be capable of binding to platelet-TLRs and inducing both the activation and promotion of downstream proinflammatory signaling cascade.

Conclusion

It is possible that the increased TLRs expression and TLR-mediated platelets activation during COVID-19 may enhance vascular and coronary thrombosis. It may be hypothesized using TLRs antagonist and monoclonal antibody against P-selectin, as the marker of leukocyte recruitment and platelet activation, besides viral therapy provide therapeutic advances in fighting against the thrombosis related complications in COVID-19.

A High-Cholesterol Diet Increases Toll-like Receptors and Other Harmful Factors in the Rabbit Myocardium: The Beneficial Effect of Statins

BACKGROUND

A high-cholesterol diet (HCD) induces vascular atherosclerosis through vascular inflammatory and immunological processes via TLRs. The aim of this study is to investigate the mRNA expression of TLRs and other noxious biomarkers expressing inflammation, fibrosis, apoptosis, and cardiac dysfunction in the rabbit myocardium during (a) high-cholesterol diet (HCD), (b) normal diet resumption and (c) fluvastatin or rosuvastatin treatment.

METHODS

Forty-eight male rabbits were randomly divided into eight groups (n = 6/group). In the first experiment, three groups were fed with HCD for 1, 2 and 3 months. In the second experiment, three groups were fed with HCD for 3 months, followed by normal chow for 1 month and administration of fluvastatin or rosuvastatin for 1 month. Control groups were fed with normal chow for 90 and 120 days. The whole myocardium was removed; total RNA was isolated from acquired samples, and polymerase chain reaction, reverse transcription PCR and quantitative real-time PCR were performed.

RESULTS

mRNA of TLRs 2, 3, 4 and 8; interleukin-6; TNF-a; metalloproteinase-2; tissue inhibitor of metalloproteinase-1; tumor protein 53; cysteinyl aspartate specific proteinase-3; and brain natriuretic peptide (BNP) increased in HCD. Statins but not resumption of a normal diet decreased levels of these biomarkers and increased levels of antifibrotic factors.

CONCLUSIONS

HCD increases the levels of TLRs; inflammatory, fibrotic and apoptotic factors; and BNP in the rabbit myocardium. Atherogenic diets adversely affect the myocardium at a molecular level and are reversed by statins.

Toll-like receptor 3 mediates ischaemia/reperfusion injury after cardiac transplantation

OBJECTIVES

Ischaemia and subsequent reperfusion during heart transplantation inevitably result in donor organ injury. Toll-like receptor (TLR)-3 is a pattern recognition receptor activated by viral and endogenous RNA released by injured cells. We hypothesized that ischaemia/reperfusion injury (IRI) leads to RNA release with subsequent TLR3 activation in transplanted hearts.

METHODS

Human endothelial cells were subjected to IRI and treated with TLR3 agonist polyinosinic-polycytidylic acid or a TLR3/double-stranded RNA complex inhibitor. TLR3 activation was analysed using reporter cells. Gene expression profiles were evaluated via next-generation sequencing. Neutrophil adhesion was assessed in vitro. Syngeneic heart transplantation of wild-type or Tlr3-/- mice was performed following 9 h of cold ischaemia. Hearts were analysed for inflammatory gene expression, cardiac damage, apoptosis and infiltrating leucocytes.

RESULTS

IRI resulted in RNA release with subsequent activation of TLR3. Treatment with a TLR3 inhibitor abrogated the inflammatory response upon IRI. In parallel, TLR3 stimulation caused activation of the inflammasome. Endothelial IRI resulted in TLR3-dependent adhesion of neutrophils. Tlr3-/- animals showed reduced intragraft and splenic messenger ribonucleic acid (mRNA) expression of proinflammatory cytokines, resulting in decreased myocardial damage, apoptosis and infiltrating cells. Tlr3 deficiency protected from cardiac damage, apoptosis and leucocyte infiltration after cardiac transplantation.

CONCLUSIONS

We uncover the release of RNA by injured cells with subsequent activation of TLR3 as a crucial pathomechanism of IRI. Our data indicate that TLR3 represents a novel target in the prevention of IRI in solid organ transplantation.

Cellular Signal Transduction Pathways Involved in Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (II/R) injury is a common type of tissue and organ injury, secondary to intestinal and mesenteric vascular diseases. II/R is characterized by a high incidence rate and mortality. In the II/R process, intestinal barrier function is impaired and bacterial translocation leads to excessive reactive oxygen species, inflammatory cytokine release, and even apoptosis. A large number of inflammatory mediators and oxidative factors are released into the circulation, leading to severe systemic inflammation and multiple organ failure of the lung, liver, and kidney. Acute lung injury (ALI) is the most common complication, which gradually develops into acute respiratory distress syndrome and is the main cause of its high mortality. This review summarizes the signal transduction pathways and key molecules in the pathophysiological process of ALI induced by II/R injury and provides a new therapeutic basis for further exploration of the molecular mechanisms of ALI induced by II/R injury. In particular, this article will focus on the biomarkers involved in II/R-induced ALI.

Sulforaphane and Albumin Attenuate Experimental Intestinal Ischemia-Reperfusion Injury

BACKGROUND

Intestinal ischemia-reperfusion (I/R) injury constitutes a severe disorder, in great part resulting from oxidative stress. Because sulforaphane and albumin were shown to increase antioxidant defenses, we evaluated the therapeutic potential of these agents in an experimental model of I/R injury.

METHODS

Wistar rats were used to establish a model of intestinal I/R (35 min of ischemia, followed by 45 min of reperfusion) and were treated with albumin (5 mL/kg), sulforaphane (500 μg/kg), or saline intravenously before reperfusion. Animals that were not subjected to I/R served as the sham (laparotomy only) and control groups. Blood samples were analyzed for arterial gas, reactive oxygen species, and reactive nitrogen species using different molecular fluorescent probes. After euthanasia, ileal samples were collected for analysis, including histopathology, immunohistochemistry, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling assays, and lactic dehydrogenase measurement.

RESULTS

Oxygenation status and hemodynamic parameters were uniform during the experiment. The sulforaphane- or albumin-treated groups showed reduced concentrations of reactive oxygen species (P < 0.04), nitric oxide (P < 0.001), and peroxynitrite (P = 0.001), compared with I/R injury untreated animals. Treatment with sulforaphane or albumin resulted in the preservation of goblet cells (P < 0.03), reductions in histopathologic scores (P < 0.01), macrophage density (P < 0.01), iNOS expression (P < 0.004), NF-kappa B activation (P < 0.05), and apoptotic rates (P < 0.04) in the mucosa and a reduction in the concentration of lactic dehydrogenase (P < 0.04), more pronounced with sulforaphane.

CONCLUSIONS

Attenuation of intestinal I/R injury in this model probably reflects the antioxidative effects of systemic administration of both sulforaphane and albumin and reinforces their use in future translational research.

Systematic Understanding of Pathophysiological Mechanisms of Oxidative Stress-Related Conditions-Diabetes Mellitus, Cardiovascular Diseases, and Ischemia-Reperfusion Injury

Reactive oxygen species (ROS) plays a role in intracellular signal transduction under physiological conditions while also playing an essential role in diseases such as hypertension, ischemic heart disease, and diabetes, as well as in the process of aging. The influence of ROS has some influence on the frequent occurrence of cardiovascular diseases (CVD) in diabetic patients. In this review, we considered the pathophysiological relationship between diabetes and CVD from the perspective of ROS. In addition, considering organ damage due to ROS elevation during ischemia-reperfusion, we discussed heart and lung injuries. Furthermore, we have focused on the transient receptor potential (TRP) channels and L-type calcium channels as molecular targets for ROS in ROS-induced tissue damages and have discussed about the pathophysiological mechanism of the injury.

Synergistic effect of the TLR5 agonist CBLB502 and its downstream effector IL-22 against liver injury

The toll-like receptor 5 (TLR5) agonist, CBLB502/Entolimod, is a peptide derived from bacterial flagellin and has been shown to protect against radiation-induced tissue damage in animal models. Here we investigated the protective mechanism of CBLB502 in the liver using models of ischemia-reperfusion injury and concanavalin A (ConA) induced immuno-hepatitis. We report that pretreatment of mice with CBLB502 provoked a concomitant activation of NF-κB and STAT3 signaling in the liver and reduced hepatic damage in both models. To understand the underlying mechanism, we screened for cytokines in the serum of CBLB502 treated animals and detected high levels of IL-22. There was no transcriptional upregulation of IL-22 in the liver, rather it was found in extrahepatic tissues, mainly the colon, mesenteric lymph nodes (MLN), and spleen. RNA-seq analysis on isolated hepatocytes demonstrated that the concomitant activation of NF-κB signaling by CBLB502 and STAT3 signaling by IL-22 produced a synergistic cytoprotective transcriptional signature. In IL-22 knockout mice, the loss of IL-22 resulted in a decrease of hepatic STAT3 activation, a reduction in the cytoprotective signature, and a loss of hepatoprotection following ischemia-reperfusion-induced liver injury. Taken together, these findings suggest that CBLB502 protects the liver by increasing hepatocyte resistance to acute liver injury through the cooperation of TLR5-NF-κB and IL-22-STAT3 signaling pathways.

Complement Initiation Varies by Sex in Intestinal Ischemia Reperfusion Injury

Intestinal ischemia reperfusion (IR)-induced tissue injury represents an acute inflammatory response with significant morbidity and mortality. The mechanism of IR-induced injury is not fully elucidated, but recent studies suggest a critical role for complement activation and for differences between sexes. To test the hypothesis that complement initiation differs by sex in intestinal IR, we performed intestinal IR on male and female WT C57B6L/, C1q-/-, MBL-/-, or properdin (P)-/- mice. Intestinal injury, C3b and C5a production and ex vivo secretions were analyzed. Initial studies demonstrated a difference in complement mRNA and protein in male and female WT mice. In response to IR, male C1q-, MBL- and P-deficient mice sustained less injury than male WT mice. In contrast, only female MBL-/- mice sustained significantly less injury than female wildtype mice. Importantly, wildtype, C1q-/- and P-/- female mice sustained significant less injury than the corresponding male mice. In addition, both C1q and MBL expression and deposition increased in WT male mice, while only elevated MBL expression and deposition occurred in WT female mice. These data suggested that males use both C1q and MBL pathways, while females tend to depend on lectin pathway during intestinal IR. Females produced significantly less serum C5a in MBL-/- and P-/- mice. Our findings suggested that complement activation plays a critical role in intestinal IR in a sex-dependent manner.

Multifaceted roles of Toll-like receptors in acute kidney injury

Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) in the first line defense system of our bodies; they are widely expressed on leukocytes and kidney epithelial cells. Infections due to pathogens or danger signals from injured tissues often activate several TLRs and these receptors mediate their signal transduction through the activation of transcription factors that regulate the expression of cytokine interleukin-1β (IL-1β), type I interferons (IFNs), and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) dependent cytokines and chemokines. Acute kidney injury (AKI) involves early Toll-like receptors driven immunopathology, while resolution of inflammation is needed for rapid regeneration of injured tubular cells. Despite their well known function in the progression of inflammation; interestingly, activation of TLRs also has been implicated in renal epithelial repair through the induction of certain interleukins and improvement in autophagy mechanism. Studies have found that although the blockade of TLRs during the early injury phase of renal tissues prevented tubular necrosis, suppression of interleukins production and impaired kidney regeneration due to their blockade has been observed during the healing phase of tissue. Taken together, these results suggest that the two danger response programs of renal cells i.e. renal inflammation and regeneration may link at the level of TLRs. This review aims to emphasize on the role of TLRs signaling in different acute kidney injury phases. Understanding of these pathways may turn out to be effective as therapeutic option for kidney diseases.

Resatorvid Relieves Breast Cancer Complicated with Depression by Inactivating Hippocampal Microglia Through TLR4/NF-κB/NLRP3 Signaling Pathway

Background

Breast cancer is one of the most common cancer with high risk in females all over the world. It is usually complicated with depression, which can further accelerate the development and progression of breast tumors. We aim to identify a new drug and identify its functional mechanism in the regulation of hippocampal microglia (MG) in breast cancer complicated with depression (BCCD).

Methods

The activation model of MG was established by treatments from corticosterone (CORT) or lipopolysaccharides (LPS). The inhibitory effects of resatorvid on MG were investigated by CCK-8, ROS, immunofluorescence, TUNEL, scratch test, ELISA, RT-qPCR and Western blot. BCCD animal model was established using 4T1 inflammatory breast cancer cells and CORT treatment in vitro. Open field experiment (OFE), tail suspension test (TST), ELISA, RT-qPCR and Western blot experiments were utilized to examine the effects of resatorvid on the animal model in vivo.

Results

The cell viability and migration ability of the BCCD model group were suppressed. The expressions of inflammatory factors, ROS, and the apoptotic rate of the BCCD model group were up-regulated, in contrast to the control group. The expressions related to the TLR4/NF-κB/NLRP3 signaling in the BCCD model group were also elevated. Resatorvid reversed the above changes, which showed good therapeutic effects in depression-related behavioral changes, tumor treatment, and blood–brain barrier function.

Conclusion

In summary, resatorvid inhibited the activation of hippocampal MG in BCCD by regulating TLR4/NF-κB/NLRP3 signaling pathway.

Dexmedetomidine Resists Intestinal Ischemia-Reperfusion Injury by Inhibiting TLR4/MyD88/NF-κB Signaling

BACKGROUND

Intestinal ischemia/reperfusion (I/R) is a common clinical problem that occurs during various clinical pathological processes. Dexmedetomidine (DEX), a widely used anesthetic adjuvant agent, can induce protection against intestinal I/R in vivo; however, the underlying mechanism is not fully understood. In the present study, we aimed to investigate the protective effects of DEX and examine whether its mechanism was associated with the TLR4/MyD88/NF-κB signaling pathway.

METHODS

Sprague-Dawley rats were pretreated with DEX and then subjected to I/R-induced intestinal injury. In vivo, intestinal histopathological examination and scoring were performed, the levels of serum intestinal fatty acid-binding protein (I-FABP), intestinal tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and expression levels of TLR4, MyD88, and NF-κB in the intestine were determined. In in vitro experiments, the human colon carcinoma cell line (Caco-2) was incubated with DEX before deprivation/reoxygenation (OGD/R) treatment. The cell viability of Caco-2 cells, the levels of lactate dehydrogenase (LDH), TNF-α, and IL-1β in the supernatant, as well as protein expression of TLR4, MyD88, and NF-κB in Caco-2 cells, were measured. Statistical analysis was performed using SPSS version 21.0.

RESULTS

DEX preconditioning significantly reduced the intestinal pathological Chiu's score, serum I-FABP, intestinal TNF-α, IL-1β levels, and the protein expression of TLR4, MyD88, and NF-κB in the rats with intestinal I/R injury. Similarly, in vitro, DEX pretreatment protected against OGD/R-induced Caco-2 cell damage and inhibited TLR4/MyD88/NF-κB signaling, as evidenced by increased cell viability, decreased LDH activity, reduced TNF-α and IL-1β levels, as well as downregulated TLR4, MyD88, and NF-κB protein levels.

CONCLUSIONS

Our findings suggested that DEX could reduce intestinal I/R injury in rats and OGD/R damage in Caco-2 cells, and this protection might be attributed to antiinflammatory effects and inhibition of the TLR4/MyD88/NF-κB signaling pathway.

Lack of sphingomyelin synthase 2 reduces cerebral ischemia/reperfusion injury by inhibiting microglial inflammation in mice

Recanalization of blood flow after ischemia can lead to ischemia/reperfusion injury, and inflammation plays an important role in the mechanisms behind cerebral ischemia/reperfusion injury. Sphingomyelin synthase 2 (SMS2) deficiency reduces inflammation; however, the effect and mechanism of action of SMS2 on the inflammatory response after cerebral ischemia/reperfusion injury are still unclear. Wild-type (WT) and SMS2 knockout C57BL/6 mice were used to establish a model of cerebral ischemia/reperfusion. The neurological deficit score was evaluated with Longa's method, and infarct volume was evaluated by magnetic resonance imaging and 2,3,5-triphenyltetrazolium chloride staining. Neurological deficit and infarct volume were used to evaluate the degree of cerebral ischemia/reperfusion injury in mice. Western blotting, reverse transcription-quantitative PCR and immunofluorescence were used to detect the expression profiles. The neurological deficit score of SMS2^-/- mice was significantly lower than that of WT mice at 72 h after cerebral ischemia/reperfusion injury (P=0.027), but not significantly different at 24 h (P=0.064). Compared with WT mice at 24 and 72 h after cerebral ischemia/reperfusion, the infarct volume of SMS2^-/- mice was decreased, the expression of pro-inflammatory cytokines galectin 3 and interleukin-1β were decreased, the activation of microglia was decreased, and the nuclear translocation of NF-κB p65 was decreased, but the expression of the anti-inflammatory factor arginase 1 was increased. Lack of SMS2 in mice can help to reduce the inflammatory reaction by inhibiting the activation of NF-κB signaling pathway, further attenuating cerebral ischemia/reperfusion injury in mice.

Assessment of Post-Resuscitation Intestinal Injury and Timing of Bacterial Translocation in Swine Anaesthetized With Propofol-Based Total Intravenous Anaesthesia

Introduction and objectives Bacterial translocation (BT) is the passage of viable bacteria or endotoxins from the gastrointestinal lumen to extra-luminal tissues and is usually observed after intestinal ischaemia-reperfusion injury. The aim of this study was to investigate post-resuscitation BT after cardiac arrest and resuscitation in a swine anaesthetized with propofol-based total intravenous anaesthesia. Materials and methods Eighteen female Landrace/Large White piglets were randomly divided into control (CON), cardiac arrest (CA) and cardiac arrest-cardiopulmonary resuscitation (CA-CPR) groups. In the CON group, the animals were only monitored for two hours. In the CA group, the animals were not resuscitated and underwent necropsy immediately after cardiac arrest. In the CA-CPR group, the animals were resuscitated until the return of spontaneous circulation (ROSC) and were monitored for two hours. The animals of the CON and CA-CPR groups underwent necropsy 24 hours later. Bacterial translocation was assessed by blood and tissue cultures and endotoxin measurement in the portal and systemic circulation. Malondialdehyde content calculation and histological analysis of the intestine were performed in order to estimate ischemia and reperfusion (I/R) tissue damage. Results  Malondialdehyde content, an indicator of oxidative stress, was significantly higher in the CA-CPR group compared to the CA in homogenized ileum (p=0.016). Malondialdehyde content in homogenized colon revealed significantly higher levels in the CA-CPR group compared to the CON (p=0.004) and the CA group (p=0.016). We found significantly higher levels of portal endotoxin in the CA-CPR group compared to the CON (p=0.026) and the CA group (p=0.026). The number of positive mesenteric lymph nodes cultures for E. coli was greater in the CA-CPR group, followed by the CA and CON groups, although the difference was not significant (67%, 33%, and 33%, respectively; p=0.407). Conclusions Malondialdehyde content and portal endotoxin levels do not increase during the cardiac arrest interval, but only after CPR and ROSC. Although the number of positive MLNs cultures was greater in the CA-CPR animals, no statistically significant differences were observed between the three groups due to the short monitoring period.

MicroRNA-18a-5p mitigates oxygen-glucose-deprivation/reoxygenation-induced injury through suppression of TLRs/NF-κB signaling by targeting TLR8 in PC12 cells

This work aimed to assess the role of TLR8 in cerebral I/R injury and its in-depth pathogenesis. Bioinformatics analysis indicated that TLR8 was up-regulated in patients with ischemic stroke than that in healthy control, and miR-18a-5p was the upstream regulatory of TLR8. Then, the rat pheochromocytoma PC12 cells were exposed in oxygen-glucose-deprivation/reoxygenation (OGD/R) conditions to construct a model in vitro. The functional experiments indicated that OGD/R can decline the viability and elevate the apoptosis of PC12 cells, while up-regulation of miR-18a-5p can alleviate OGD/R-induced cell injury. Notably, overexpression of TLR8 reverses the miR-18a-5p-mediated protection on OGD/R-induced cells injury. Finally, we found that up-regulation of miR-18a-5p obviously declined the protein levels of TLR4 and TLR7 as well as the phosphorylation of NF-κB, while overexpression of TLR8 canceled the decrease caused by miR-18a-5p up-regulation. In summing, our results illustrated that miR-18a-5p/TLR8 axis can mitigate OGD/R-induced cells injury through TLRs and NF-κB pathway.