NLRC5 alleviated OGD/R-induced PC12-cell injury by inhibiting activation of the TLR4/MyD88/NF-κB pathway

Investigation of the role of NLRP3 inflammasome activation in new-generation BCR-ABL1 tyrosine kinase inhibitors-induced hepatotoxicity

New generation BCR-ABL1 TKIs raised attention regarding their adverse effects, including hepatotoxicity. Indeed, bosutinib and nilotinib were associated with severe hepatotoxicity compared with imatinib. Moreover, ponatinib has a boxed warning due to its potential to cause inflammatory liver damage, even death. However, the underlying mechanisms remain unclear. This study aimed to investigate the role of NLRP3 inflammasome activation in the underlying mechanism of ponatinib and bosutinib-induced hepatotoxicity. Furthermore, we determined the initiating event of this adverse outcome pathway by measuring the levels of reactive oxygen species as well as mitochondrial membrane potential in AML12 cells. The results demonstrated that ponatinib or bosutinib markedly inhibited cell viability and caused cytosolic membrane damage in cells. Moreover, drugs (IC50) dramatically induced oxidative stress and mitochondrial membrane potential disruption, which led to upregulation in the expression levels of NLRP3 inflammasome-related genes and proteins, activation of NLRP3 inflammasomes, cleavage of gasdermin-D and caspase-1, secretion of IL-1β, and cytosolic membrane damage. Furthermore, MCC950, a well-known specific inhibitor of NLRP3 inflammasome, and antioxidant N-acetyl-l-cysteine reversed the effects of drugs on the NLRP3 signaling pathway and cytosolic membranes. In summary, NLRP3 inflammasome activation is involved in new-generation BCR-ABL1 TKIs-triggered hepatotoxicity. Mitochondrial damage and reactive oxygen species accumulation were significant upstream signaling events in this signaling pathway.

Sinigrin improves cerebral ischaemia-reperfusion injury by inhibiting the TLR4 pathway-mediated oxidative stress

Cerebral ischaemia-reperfusion (CIR) injury occurs in stroke patients after the restoration of cerebral perfusion. Sinigrin, a phytochemical found in cruciferous vegetables, exhibits strong antioxidant activity. This study investigated the role of sinigrin in oxidative stress using a CIR injury model. The effects of sinigrin were studied in middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-injured SH-SY5Y cells. Sinigrin treatment improved brain injury and neurological deficits induced by MCAO surgery in rats. Sinigrin inhibited apoptosis in brain tissues and SH-SY5Y cells following OGD/R induction. Additionally, sinigrin elevated the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) while reducing malondialdehyde (MDA) levels. Furthermore, sinigrin inhibited the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signalling pathway. The anti-apoptotic and antioxidant activities of sinigrin in OGD/R-injured SH-SY5Y cells were reversed by TLR4 overexpression. In conclusion, sinigrin inhibits oxidative stress in CIR injury by suppressing the TLR4/MyD88 signalling pathway.

Exploring Chinese herbal medicine for ischemic stroke: insights into microglia and signaling pathways

Ischemic stroke is a prevalent clinical condition affecting the central nervous system, characterized by a high mortality and disability rate. Its incidence is progressively rising, particularly among younger individuals, posing a significant threat to human well-being. The activation and polarization of microglia, leading to pro-inflammatory and anti-inflammatory responses, are widely recognized as pivotal factors in the pathogenesis of cerebral ischemia and reperfusion injury. Traditional Chinese herbal medicines (TCHMs) boasts a rich historical background, notable efficacy, and minimal adverse effects. It exerts its effects by modulating microglia activation and polarization, suppressing inflammatory responses, and ameliorating nerve injury through the mediation of microglia and various associated pathways (such as NF-κB signaling pathway, Toll-like signaling pathway, Notch signaling pathway, AMPK signaling pathway, MAPK signaling pathway, among others). Consequently, this article focuses on microglia as a therapeutic target, reviewing relevant pathway of literature on TCHMs to mitigate neuroinflammation and mediate IS injury, while also exploring research on drug delivery of TCHMs. The ultimate goal is to provide new insights that can contribute to the clinical management of IS using TCHMs.

Curcumin in vitro Neuroprotective Effects Are Mediated by p62/keap-1/Nrf2 and PI3K/AKT Signaling Pathway and Autophagy Inhibition

Oxidative stress and autophagy are potential mechanisms associated with cerebral ischemia/reperfusion injury (IRI) and is usually linked to inflammatory responses and apoptosis. Curcumin has recently been demonstrated to exhibit anti-inflammatory, anti-oxidant, anti-apoptotic and autophagy regulation properties. However, mechanism of curcumin on IRI-induced oxidative stress and autophagy remains not well understood. We evaluated the protective effects and potential mechanisms of curcumin on cerebral microvascular endothelial cells (bEnd.3) and neuronal cells (HT22) against oxygen glucose deprivation/reoxygenation (OGD/R) in vitro models that mimic in vivo cerebral IRI. The cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) activity assays revealed that curcumin attenuated the OGD/R-induced injury in a dose-specific manner. OGD/R induced elevated levels of inflammatory cytokines TNF-alpha, IL-6 as well as IL-1beta, and these effects were notably reduced by curcumin. OGD/R-mediated apoptosis was suppressed by curcumin via upregulating B-cell lymphoma-2 (Bcl-2) and downregulating Bcl-associated X (Bax), cleaved-caspase3 and TUNEL apoptosis marker. Additionally, curcumin increased superoxide dismutase (SOD) and glutathione (GSH), but suppressed malondialdehyde (MDA) and reactive oxygen species (ROS) content. Curcumin inhibited the levels of autophagic biomarkers such as LC3 II/LC3 I and Beclin1. Particularly, curcumin induced p62 accumulation and its interactions with keap1 and promoted NF-E2-related factor 2 (Nrf2) translocation to nucleus, accompanied by increased NADPH quinone dehydrogenase (Nqo1) and heme oxygenase 1 (HO-1). Treatment of curcumin increased phosphorylation-phosphatidylinositol 3 kinase (p-PI3K) and p-protein kinase B (p-AKT). The autophagy inhibitor 3-methyladenine (3-MA) activated the keap-1/Nrf2 and PI3K/AKT pathways. This study highlights the neuroprotective effects of curcumin on cerebral IRI.

Geniposidic acid protects lipopolysaccharide-induced acute lung injury via the TLR4/MyD88 signaling pathway in vitro and in vivo

BACKGROUND

Acute lung injury (ALI) is a common respiratory disease and is a serious threat to human health due to the lack of effective treatment. Geniposidic acid (GPA) is an iridoid glucoside extracted from Gardeniae jasminoides Ellis and can treat inflammation-related diseases. This study aimed to investigate the regulatory functions of GPA on lipopolysaccharide (LPS)-induced ALI and its potential mechanism, providing effective strategies for the clinical treatment of ALI.

METHODS

ALI models were constructed by LPS in Sprague-Dawley rats and pulmonary epithelial cells. The function of GPA was investigated by hematoxylin-eosin staining, lung function assessment, Western blot, Masson staining, and Sirius Red staining, quantitative real-time PCR, enzyme-linked immunosorbent assay, cell counting kit-8 assay, apoptosis analysis, and immunofluorescence assays.

RESULTS

Functionally, GPA increased survival, relieved pulmonary epithelial function in response to LPS, repressed pulmonary fibrosis and inflammation caused by ALI in vivo; GPA also repressed pulmonary epithelial cell injury and inflammation induced by LPS in vitro. Mechanistically, GPA decreased the protein levels of TLR4 and MyD88 and accelerated the nuclear export of p65, suggesting that GPA repressed the activation of p65.

CONCLUSION

GPA protected LPS-induced ALI through the TLR4/MyD88 signaling pathway.

Neuroprotective effects of a novel peptide from Lignosus rhinocerotis against 6‐hydroxydopamine‐induced apoptosis in PC12 cells by inhibiting NF‐κB activation

According to previous studies, oxidative stress is a leading cause of dopaminergic neuron death and may contribute to the pathogenesis of Parkinson's disease (PD). In the current study, we used chromatography of gel filtration to identify a novel peptide (Lignosus rhinocerotis peptide [LRP]) from the sclerotium of Lignosus rhinocerotis (Cooke) Ryvarden. Its neuroprotective effect was evaluated using an in vitro PD model constructed by 6-hydroxydopamine (6-OHDA)-stimulated to apoptosis in PC12 cells. The molecular weight of LRP is determined as 1532 Da and the secondary structure is irregular. The simple amino acid sequence of LRP is Thr-Leu-Ala-Pro-Thr-Phe-Leu-Ser-Ser-Leu-Gly-Pro-Cys-Leu-Leu. Notably, LRP has the ability to significantly boost the viability of PC12 cells after exposure to 6-OHDA, as well as enhance the cellular activity of antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). LRP also lowers the level of malondialdehyde (MDA), decreases the activation performance of Caspase-3, and reduces 6-OHDA-induced apoptosis via inhibition of nuclear factor-kappa B (NF-κB) activation. These data indicate that LRP may have the potential to act as a neuroprotective agent.

Expression pattern of NLRC5 in the postnatal mouse brain

Nucleotide oligomerization domain-like receptors (NLRs), belonging to a large family of pattern recognition receptors, participate in the host's first line of defense against invading pathogens. Caspase recruitment domain containing 5 (NLRC5), the largest member in the NLR family, is demonstrated to be involved in the innate immune response and inflammatory diseases far and wide. Recent studies report that NLRC5 is associated with some central nervous system (CNS) diseases. Besides, NLRC5 is a mastery regulator for the expression of MHC class I both in the immune system and the CNS, while MHC class I is expressed and exerts its function in the brain. Therefore, it is necessary to investigate the expression pattern of NLRC5 in the developing and adult CNS. In our study, postnatal brain sections of C57BL/6 J mice are analyzed for the expression of NLRC5 protein by immunofluorescence. In the postnatal stages of developing telencephalon, NLRC5 exhibits a spatial and temporal expression pattern. NLRC5 is time-specifically expressed in subfields of hippocampus and different layers of prefrontal cortex. Moreover, it is shown that NLRC5 is highly cell type specific. It can be expressed in large quantities by neurons and microglia, but rarely expressed by astrocytes. Taken together, our research is important for further understanding the biological characteristics of NLRC5 and its function in the CNS.

Enhanced treatment of cerebral ischemia-Reperfusion injury by intelligent nanocarriers through the regulation of neurovascular units

Reperfusion injury is one of the major causes of disability and death caused by ischemic stroke, and drug development focuses mainly on single neuron protection. However, different kinds of cells in the neurovascular units (NVUs), including neurons, microglia and vascular endothelial cells, are pathologically changed after cerebral ischemia-reperfusion injury, resulting in an urgent need to develop a drug delivery system to comprehensively protect the kinds of cells involved in the NVU. Herein, we have constructed a c(RGDyK) peptide modified, NF-κB inhibitor caffeic acid phenethyl ester (CAPE)-loaded and reactive nitrogen species (RNS) stimuli-responsive liposomal nanocarrier (R-Lipo-CAPE) to target ischemic lesions and then remodel the NVU to reduce the progression of cerebral ischemia-reperfusion injury. The R-Lipo-CAPE liposomes were approximately 170 nm with a zeta potential of -30.8 ± 0.2 mV. The in vitro CAPE release behavior from R-Lipo-CAPE showed an RNS-dependent pattern. For in vivo studies, transient middle cerebral artery occlusion/reperfusion (MCAO) model mice treated with R-Lipo-CAPE had the least neurological impairment and decreased brain tissue damage, with an infarct area of 13%, compared with those treated with saline of 53% or free CAPE of 38%. Furthermore, microglia in the ischemic brain were polarized to the tissue-repairing M2 phenotype after R-Lipo-CAPE treatment. In addition, R-Lipo-CAPE-treated mice displayed a prominent down-regulated expression of MMP-9 and restored expression of the tight junction protein claudin-5. This proof-of-concept indicates that R-Lipo-CAPE is a promising nanomedicine for the treatment of cerebral ischemia-reperfusion injury through the regulation of neurovascular units. STATEMENT OF SIGNIFICANCE: Based on the complex mechanism and difficulty in treatment of cerebral ischemia-reperfusion injury, the overall regulation of neurovascular unit has become an extremely important target. However, little nanomedicine has been directed to remodel the neurovascular units in targeted cerebral ischemia-reperfusion injury therapy. Here, c(RGDyK) peptide modified reactive nitrogen species (RNS) stimuli-responsive liposomal nanocarrier loaded with a NF-κB inhibitor (CAPE), was designed to simultaneously regulate various cells in the microenvironment of cerebral ischemia-reperfusion injury to remodel the neurovascular units. Our in vitro and in vivo data showed that the intelligent nanocarrier exerted the ability of pathological signal stimuli-responsive drug release, cerebral ischemia-reperfusion injury site targeting and neurovascular units remodeling through reducing neuron apoptosis, regulating microglia polarization and repairing vascular endothelial cell. Overall, the intelligent liposomal drug delivery system was a promising and safe nanomedicine in the perspective of cerebral ischemia-reperfusion injury treatment.

SET domain containing 7 promotes oxygen-glucose deprivation/reoxygenation-induced PC12 cell inflammation and oxidative stress by regulating Keap1/Nrf2/ARE and NF-κB pathways

Oxidative stress and inflammation are implicated in the pathogenesis of cerebral ischemia-reperfusion (I/R) injury. SETD7 (SET Domain Containing 7) functions as a histone lysine methyltransferase, participates in cardiac lineage commitment, and silence of SETD7 exerts anti-inflammatory or antioxidant capacities. The effect of SETD7 in in vitro cell model of cerebral I/R injury was investigated in this study. Firstly, adrenal pheochromocytoma cell (PC12) was conducted with oxygen-glucose deprivation/reoxygenation (OGD/R) to establish cell model of cerebral I/R injury. OGD/R-enhanced SETD7 expression in PC12 cells. Cell viability of OGD/R-induced PC12 was reduced, while the apoptosis was promoted. Secondly, knockdown of SETD7 reversed the effect of OGD/R on cell viability and apoptosis of PC12. Moreover, OGD/R-induced inflammation in PC12 with decreased interleukin (IL)-10, increased IL-6, IL-1β, tumor necrosis factor-α (TNF-α), and cyclooxygenase 2 (COX-2) were restored by knockdown of SETD7. Thirdly, knockdown of SETD7 attenuated OGD/R-induced decrease of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT), as well as increase of malondialdehyde (MDA) and reactive oxygen species (ROS) in PC12. Lastly, OGD/R-induced decrease of NF-κB inhibitor α (IκBα), increase of phosphorylated (p)-p65, p-IκBα, and Keap1 (Kelch-like ECH-associated protein 1) were reversed by silence of SETD7. Silence of SETD7 increased heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) expression in OGD/R-induced PC12. In conclusion, suppression of SETD7 ameliorated OGD/R-induced inflammation and oxidative stress in PC12 cell through inactivation of NF-κB and activation of Keap1/Nrf2/ARE pathway.

Roles of PRR-Mediated Signaling Pathways in the Regulation of Oxidative Stress and Inflammatory Diseases

Oxidative stress is a major contributor to the pathogenesis of various inflammatory diseases. Accumulating evidence has shown that oxidative stress is characterized by the overproduction of reactive oxygen species (ROS). Previous reviews have highlighted inflammatory signaling pathways, biomarkers, molecular targets, and pathogenetic functions mediated by oxidative stress in various diseases. The inflammatory signaling cascades are initiated through the recognition of host cell-derived damage associated molecular patterns (DAMPs) and microorganism-derived pathogen associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs). In this review, the effects of PRRs from the Toll-like (TLRs), the retinoic acid-induced gene I (RIG-I)-like receptors (RLRs) and the NOD-like (NLRs) families, and the activation of these signaling pathways in regulating the production of ROS and/or oxidative stress are summarized. Furthermore, important directions for future studies, especially for pathogen-induced signaling pathways through oxidative stress are also reviewed. The present review will highlight potential therapeutic strategies relevant to inflammatory diseases based on the correlations between ROS regulation and PRRs-mediated signaling pathways.

NLRC5: A Potential Target for Central Nervous System Disorders

Nucleotide oligomerization domain-like receptors (NLRs), a class of pattern recognition receptors, participate in the host’s first line of defense against invading pathogenic microorganisms. NLR family caspase recruitment domain containing 5 (NLRC5) is the largest member of the NLR family and has been shown to play an important role in inflammatory processes, angiogenesis, immunity, and apoptosis by regulating the nuclear factor-κB, type I interferon, and inflammasome signaling pathways, as well as the expression of major histocompatibility complex I genes. Recent studies have found that NLRC5 is also associated with neuronal development and central nervous system (CNS) diseases, such as CNS infection, cerebral ischemia/reperfusion injury, glioma, multiple sclerosis, and epilepsy. This review summarizes the research progress in the structure, expression, and biological characteristics of NLRC5 and its relationship with the CNS.