Anti-inflammatory and anti-apoptotic effects of the combination of Ligusticum chuanxiong and Radix Paeoniae against focal cerebral ischaemia via TLR4/MyD88/MAPK/NF-κB signalling pathway in MCAO rats

The impact of cytokines in neuroinflammation-mediated stroke

Cerebral stroke is ranked as the third most common contributor to global mortality and disability. The involvement of inflammatory mechanisms, both peripherally and within the CNS, holds significance in the pathophysiological cascades following the initiation of stroke. After the onset of acute stroke, predominantly ischemic, a subsequent phase of neuroinflammation ensues. It is a dual-effect process that not only exacerbates injury, leading to cell death, but paradoxically, it also serves a shielding role in facilitating recovery. Cytokines serve as pivotal mediators within the inflammatory cascade, actively contributing to the progression of ischemic damage. Stroke is followed by increased expression of pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, etc. leading to the recruitment and stimulation of glial cells and peripheral leukocytes at the site of injury, promoting neuroinflammation. Cytokines can directly induce neuronal injury and death through various mechanisms, including excitotoxicity, oxidative stress, HPA-axis activation, secretion of matrix metalloproteinase and apoptosis. They can also amplify the inflammatory response, leading to further neuronal damage. Therapeutic strategies aimed at modulating cytokine release, immune response and cytokine signalling or activity are being explored as potential interventions to mitigate neuroinflammation and its detrimental effects in stroke. In this review, we have given a concise summary of our current knowledge of the function of various cytokines, brain inflammation and various signalling and molecular pathways including JAK/STAT3, TGF-β/Smad, MAPK, HMGB1/TLR and NF-κB modulated cytokines regulation in stroke. Therapeutic agents such as MCC950, genistein, edaravone, minocycline, etc. targeting various cytokines-associated signalling pathways have shown efficacy in preclinical and clinical trials reducing the pathophysiology of the illness were also addressed in this study.

Baicalein ameliorates cognitive impairment of vascular dementia rats via suppressing neuroinflammation and regulating intestinal microbiota

Neuroinflammation induced by chronic cerebral hypoperfusion (CCH) plays a crucial role in the pathophysiologic mechanisms of vascular dementia (VD). A growing body of research has found that intestinal microbiota is associated with a variety of central nervous system disorders and that there is a relationship between intestinal microbiota dysbiosis and cognitive dysfunction and inflammatory responses. Baicalein belongs to the class of flavonoids and has a variety of biological functions, including anti-inflammatory, antioxidant and anti-apoptotic. Baicalein has a significant improvement in memory and learning, and can be used as a potential drug for the protection and treatment of central nervous system disorders. Whether baicalein has an ameliorative effect on cognitive impairment in VD, and whether its mechanism is related to the inhibition of inflammatory response and regulation of intestinal microbiota has not been reported. We used bilateral common carotid artery occlusion (BCCAO) to establish a VD rat model. Morris water maze (MWM) test showed that baicalein improved cognitive dysfunction in VD rats. We applied HE staining, immunofluorescence and ELISA to observe that baicalein treatment significantly improved CCH-induced neuronal damage in the CA1 region of the hippocampus, and reduced glial cell activation and release of pro-inflammatory factors. Western blot showed that baicalein inhibited the activation of the TLR4/MyD88/NF-κB signaling pathway in VD rats. We applied 16 S rDNA sequencing to analyze the composition of the intestinal microbiota. The results showed that baicalein modulated the diversity and composition of the intestinal microbiota, and suppressed the relative abundance of inflammation-associated microbiota in VD rats. In conclusion, this study found that baicalein ameliorated cognitive impairment, attenuated hippocampal inflammatory responses, inhibited the TLR4/MyD88/NF-κB signaling pathway, and modulated intestinal microbiota in VD rats.

Dual-Targeted Nanoparticle-in-Microparticle System for Ulcerative Colitis Therapy

Conventional oral therapy for ulcerative colitis (UC) is associated with premature release or degradation of drugs in the harsh gastrointestinal environment, resulting in reduced therapeutic effectiveness. Consequently, the present study aims to develop a dual-targeted delivery system with a nanoparticle-in-microparticle (nano-in-micro) structure. The prepared Asiatic Acid-loaded delivery system (AA/CDM-BT-ALG) has pH-sensitive properties. Cellular uptake evaluation confirms that nanoparticles exhibit targeted absorption by macrophages and Caco-2 cells through mannose (Man) receptor and biotin-mediated endocytosis, respectively. Therefore, this mechanism effectively enhances intracellular drug concentration. Additionally, the biodistribution study conducted on the gastrointestinal tract of mice indicates that the colon of the microspheres group shows higher fluorescence intensity with longer duration than the other groups. This finding indicates that the microspheres exhibit selective accumulation in areas of colon inflammation. In vivo experiments in colitis mice showed that AA/CDM-BT-ALG significantly alleviates the histopathological characteristics of the colon, reduced neutrophil, and macrophage infiltration, and decreases pro-inflammatory cytokine expression. Furthermore, the effect of AA/CDM-BT-ALG on colitis is validated to be closely related to the TLR4/MyD88/NF-κB signaling pathway. The present findings suggest that the development of a dual-targeted delivery system is accomplished effectively, with the potential to serve as a drug-controlled release system for treating UC.

Fluoxetine alleviates postoperative cognitive dysfunction by attenuating TLR4/MyD88/NF-κB signaling pathway activation in aged mice

OBJECTIVE AND DESIGN

Postoperative cognitive dysfunction (POCD) is a common complication following surgery among elderly patients. Emerging evidence demonstrates that neuroinflammation plays a pivotal role in the pathogenesis of POCD. This study tested the hypothesis that fluoxetine can protect against POCD by suppressing hippocampal neuroinflammation through attenuating TLR4/MyD88/NF-κB signaling pathway activation.

SUBJECTS

Aged C57BL/6 J male mice (18 months old) were studied.

TREATMENT

Aged mice were intraperitoneally injected with fluoxetine (10 mg/kg) or saline for seven days before splenectomy. In addition, aged mice received an intracerebroventricular injection of a TLR4 agonist or saline seven days before splenectomy in the rescue experiment.

METHODS

On postoperative days 1, 3, and 7, we assessed hippocampus-dependent memory, microglial activation status, proinflammatory cytokine levels, protein levels related to the TLR4/MyD88/NF-κB signaling pathway, and hippocampal neural apoptosis in our aged mouse model.

RESULTS

Splenectomy induced a decline in spatial cognition, paralleled by parameters indicating exacerbation of hippocampal neuroinflammation. Fluoxetine pretreatment partially restored the deteriorated cognitive function, downregulated proinflammatory cytokine levels, restrained microglial activation, alleviated neural apoptosis, and suppressed the increase in TLR4, MyD88, and p-NF-κB p65 in microglia. Intracerebroventricular injection of LPS (1 μg, 0.5 μg/μL) before surgery weakened the effect of fluoxetine.

CONCLUSION

Fluoxetine pretreatment suppressed hippocampal neuroinflammation and mitigated POCD by inhibiting microglial TLR4/MyD88/NF-κB pathway activation in aged mice.

Network pharmacology based research into the effect and potential mechanism of Portulaca oleracea L. polysaccharide against ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) as a chronic inflammatory bowel disease (IBD) has received extensive concerns worldwide. As a traditional herbal medicine, Portulaca oleracea L. (POL) has a wide application in gastrointestinal diseases such as diarrhea and dysentery. This study aims to investigate the target and potential mechanisms of Portulaca oleracea L. polysaccharide (POL-P) in the treatment of UC.

METHOD

The active ingredients and relevant targets of POL-P were searched through the TCMSP and Swiss Target Prediction databases. UC related targets were collected through the GeneCards and DisGeNET databases. The intersection of POL-P targets with UC targets was done using Venny. Then, protein-protein interaction (PPI) network of the intersection targets was constructed through the STRING database and analyzed using Cytohubba to identify the key targets of POL-P in the treatment of UC. In addition, GO and KEGG enrichment analyses were performed on the key targets and the binding mode of POL-P to the key targets was further analyzed by molecular docking technology. Finally, the efficacy and target of POL-P were verified using animal experiments and immunohistochemical staining.

RESULTS

A total of 316 targets were obtained based on POL-P monosaccharide structures, among which 28 were related to UC. Cytohubba analysis showed that VEGFA, EGFR, TLR4, IL-1β, STAT3, IL-2, PTGS2, FGF2, HGF, and MMP9 were the key targets for UC treatment and were mainly involved in multiple signaling pathways such as proliferation, inflammation, and immune response. Molecular docking results revealed that POL-P had a good binding potential to TLR4. In vivo validation results showed that POL-P significantly reduced the overexpression of TLR4 and its downstream key proteins (MyD88 and NF-κB) in intestinal mucosa of UC mice, which indicated that POL-P improved UC by mediating TLR4 related proteins.

CONCLUSION

POL-P may be a potential therapeutic agent for UC and its mechanism is closely related to the regulation of TLR4 protein. This study will provide novel insights for the treatment of UC with POL-P.

Immunohistochemical Localization of MD2, a Co-Receptor of TLR4, in the Adult Mouse Brain

Myeloid differentiation factor 2 (MD2) is a co-receptor of a classical proinflammatory protein TLR4 whose activation leads to neuroinflammation. It is widely accepted that TLR4 is expressed on the cell surface of microglia and astrocytes, and MD2 is expected to be expressed by these cells as well. However, our previous study showed that neurons from certain nuclei also expressed MD2. Whether MD2 is expressed by other brain nuclei is still unknown. It is the aim of the present study to map the distribution of MD2-positive cells in the adult mouse brain. Immunohistochemical staining against MD2 was completed to localize MD2-positive cells in the mouse brain by comparing the location of positive cells with the mouse brain atlas. MD2-positive cells were found in the majority of mouse brain nuclei with clusters of cells in the olfactory bulb, cortices, the red nucleus, and cranial nuclei. Subcortical nuclei had heterogeneous staining of MD2 with more prominent cells in the basolateral and the central amygdaloid nuclei. The ventral pallidum and the diagonal bands had positive cells with similar density and shape. Prominent cells were present in thalamic nuclei which were nearly homogeneous and in reticular formation of the brainstem where cells were dispersed with similar density. The hypothalamus had fewer outstanding cells compared with the thalamus. The red nucleus, the substantia nigra, and the ventral tegmental area in the pretectum had outstanding cells. Motor cranial nuclei also had outstanding MD2-positive cells, whereas raphe, sensory cranial, and deep cerebellar nuclei had MD2-positive cells with moderate density. The presence of MD2 in these nuclei may suggest the involvement of MD2 in their corresponding physiological functions.

Supplementation with Tribulus Terrestris Extract Exhibits Protective Effects on MCAO Rats via Modulating Inflammation-Related Metabolic and Signaling Pathways

The extract of Tribulus terrestris (TT) has been used as a component of several nutritional supplements for enhancing human vitality. However, its protective effect on ischemic stroke has yet to be fully investigated. In this study, the middle cerebral artery occlusion (MCAO) rat model was established and treated with gross saponin of TT fruit (GSTTF) by gavage to explore its anti-ischemic stroke efficacy. Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics was applied to profile the brain tissue metabolite changes and further obtain the metabolic pathways that were greatly involved in the efficacy of GSTTF. Subsequent molecular biology experiments were applied to validate the findings from metabolomics analysis. The results showed that GSTTF administration remarkably decreased the infarction volume of brain tissue and improved the neurobehavioral scores of MCAO rats. Metabolomics analysis revealed that pathways, including glycerophospholipid metabolism, sphingolipid metabolism, and arachidonic acid metabolism, were considered associated with the protective effect of GSTTF against MCAO, which were greatly involved in the inflammatory responses. The results of the biochemistry analysis showed that GSTTF treatment significantly reduced the levels of TNF-α and IL-6 in brain tissue after MCAO. The anti-inflammatory mechanism of GSTTF was further investigated, which revealed that GSTTF could inhibit the TLR4/MyD88/NF-κB signaling pathway to exert protective effects on MCAO. This study provides the underlying anti-inflammatory mechanism of GSTTF for ischemic stroke protection, which has important implications for the development of GSTTF-related functional foods or food supplements.

Stroke: Molecular mechanisms and therapies: Update on recent developments

Stroke, a neurological disease, is one of the leading causes of death worldwide, resulting in long-term disability in most survivors. Annual stroke costs in the United States alone were estimated at $46 billion recently. Stroke pathophysiology is complex, involving multiple causal factors, among which atherosclerosis, thrombus, and embolus are prevalent. The molecular mechanisms involved in the pathophysiology are essential to understanding targeted drug development. Some common mechanisms are excitotoxicity and calcium overload, oxidative stress, and neuroinflammation. In addition, various modifiable and non-modifiable risk factors increase the chances of stroke manifolds. Once a patient encounters a stroke, complete restoration of motor ability and cognitive skills is often rare. Therefore, shaping therapeutic strategies is paramount for finding a viable therapeutic agent. Apart from tPA, an FDA-approved therapy that is applied in most stroke cases, many other therapeutic strategies have been met with limited success. Stroke therapies often involve a combination of multiple strategies to restore the patient's normal function. Certain drugs like Gamma-aminobutyric receptor agonists (GABA), Glutamate Receptor inhibitors, Sodium, and Calcium channel blockers, and fibrinogen-depleting agents have shown promise in stroke treatment. Recently, a drug, DM199, a recombinant (synthetic) form of a naturally occurring protein called human tissue kallikrein-1 (KLK1), has shown great potential in treating stroke with fewer side effects. Furthermore, DM199 has been found to overcome the limitations presented when using tPA and/or mechanical thrombectomy. Cell-based therapies like Neural Stem Cells, Hematopoietic stem cells (HSCs), and Human umbilical cord blood-derived mesenchymal stem cells (HUCB-MSCs) are also being explored as a treatment of choice for stroke. These therapeutic agents come with merits and demerits, but continuous research and efforts are being made to develop the best therapeutic strategies to minimize the damage post-stroke and restore complete neurological function in stroke patients.

Therapeutic targets by traditional Chinese medicine for ischemia-reperfusion injury induced apoptosis on cardiovascular and cerebrovascular diseases

Traditional Chinese medicine (TCM) has a significant role in treating and preventing human diseases. Ischemic heart and cerebrovascular injuries are two types of diseases with different clinical manifestations with high prevalence and incidence. In recent years, it has been reported that many TCM has beneficial effects on ischemic diseases through the inhibition of apoptosis, which is the key target to treat myocardial and cerebral ischemia. This review provides a comprehensive summary of the mechanisms of various TCMs in treating ischemic cardiovascular and cerebrovascular diseases through anti-apoptotic targets and pathways. However, clinical investigations into elucidating the pharmacodynamic ingredients of TCM are still lacking, which should be further demystified in the future. Overall, the inhibition of apoptosis by TCM may be an effective strategy for treating ischemic cardio-cerebrovascular diseases.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.

Angelica Yinzi alleviates 1-chloro-2,4-dinitrobenzene-induced atopic dermatitis by inhibiting activation of NLRP3 inflammasome and down-regulating the MAPKs/NF-kB signaling pathway

Background

Atopic dermatitis (AD), characterized by eczema as a chronic pruritic inflammatory skin disease, has become a serious health problem with recurrent clinical episodes. However, current clinical treatments have limited relief and are accompanied by adverse effects. Therefore, there is a necessity to develop new effective drugs for AD treatment. Angelica Yinzi (AYZ) is a classic ancient prescription for nourishing blood, moistening dryness, dispelling wind, and relieving itching. However, its mechanism for alleviating atopic dermatitis remains unknown. Therefore, this study aimed at determining the effects of AYZ and its potential mechanism in alleviating AD-like symptoms.

Methods

In the present study, we used 1-chloro-2,4-dinitrobenzene (DNCB) to establish a mouse model of atopic dermatitis, where DNCB readily penetrates the epidermis to cause inflammation. Histopathological analysis was performed to examine the thickening of dorsal skin and infiltration in the inflammatory and mast cells in C57BL/6 mice. Additionally, the immunoglobulin E (IgE) levels in serum were determined by enzyme-linked immunosorbent assay (ELISA) kits. The IL-1β and TNF-α expression were detected using qRT-PCR. Next, the Western blotting and immunohistochemistry assays were performed to assess the contribution of MAPKs/NF-κB signaling pathways and the NLRP3 inflammasome in AD responses.

Results

Histopathological examination revealed that AYZ reduced the epidermal thickness of AD-like lesioned skin and repressed the infiltration of mast cells into AD-like lesioned skin. AYZ significantly decreased the phosphorylation of p38 MAPK, JNK, ERK and NF-κB and downregulated serum IgE levels and IL-1β and TNF-α mRNA levels. Additionally, the NLRP3, ASC, Caspase-1, and IL-1β expression in dorsal skin were effectively down-regulated following AYZ treatment (p < 0.05 and p < 0.01).

Conclusion

These findings revealed that AYZ effectively suppressed AD-induced skin inflammation by inhibiting the activation of the NLRP3 inflammasome and the MAPKs/NF-kB signaling. Therefore, AYZ is a potential therapeutic agent against AD in the clinical setting.

A Reasonable Evaluation of Chuanxiong Rhizoma Processing with Wine through Comparative Pharmacokinetic Study of Bioactive Components: Dominant Effect on Middle Cerebral Artery Occlusion Model Rats

According to the ancient documents and Chinese herbal medicine processing experience, Chuanxiong Rhizoma was usually processed with yellow rice wine to improve efficacy. However, the relevant mechanisms are still unclear so far. In this study, a validated ultrahigh-performance liquid chromatography tandem mass spectrometry method was used to compare the pharmacokinetics of four representative components in middle cerebral artery occlusion rats after oral administration of raw and wine-processed Chuanxiong Rhizoma. The neurobehavioral scores and 2,3,5-triphenyltetrazolium chloride staining were employed to evaluate the model. Biological samples were prepared by protein precipitation with methanol. All analytes were separated on an ACQUITY BEH C₁₈ column through gradient elution using acetonitrile and 0.01% of formic acid as mobile phase, and the flow rate was 0.3 mL/min. The results showed that the maximum plasma concentrations, the area values under the concentration-time curves of senkyunolide A, and ferulic acid in wine-processed Chuanxiong Rhizoma were all higher than in raw Chuanxiong Rhizoma, which were completely opposite to our previous studies in normal rats. Compared with normal rats, the theory that wine processing could enhance the efficacy of Chuanxiong Rhizoma may be better reflected in model rats.

Research Advances in Cardio-Cerebrovascular Diseases of Ligusticum chuanxiong Hort

Cardio-cerebrovascular diseases (CVDs) are a serious threat to human health and account for 31% of global mortality. Ligusticum chuanxiong Hort. (CX) is derived from umbellifer plants. Its rhizome, leaves, and fibrous roots are similar in composition but have different contents. It has been used in Japanese, Korean, and other traditional medicine for over 2000 years. Currently, it is mostly cultivated and has high safety and low side effects. Due to the lack of a systematic summary of the efficacy of CX in the treatment of CVDs, this article describes the material basis, molecular mechanism, and clinical efficacy of CX, as well as its combined application in the treatment of CVDs, and has been summarized from the perspective of safety. In particular, the pharmacological effect of CX in the treatment of CVDs is highlighted from the point of view of its mechanism, and the complex mechanism network has been determined to improve the understanding of CX's multi-link and multi-target therapeutic effects, including anti-inflammatory, antioxidant, and endothelial cells. This article offers a new and modern perspective on the impact of CX on CVDs.

Exosomal microRNA-150-5p from bone marrow mesenchymal stromal cells mitigates cerebral ischemia/reperfusion injury via targeting toll-like receptor 5

MicroRNA (miR)-150-5p has been investigated in many studies, while the role of exosomal miR-150-5p from bone arrow mesenchymal stromal cells (BMSCs) on cerebral ischemia/reperfusion (I/R) injury is not fully explored. This research aims to probe the effects of exosomal miR-150-5p from BMSCs on cerebral I/R injury via regulating B-cell translocation gene 2 (TLR5). Bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exo) were isolated and identified. The middle cerebral artery occlusion (MCAO) rat model was established and treated by BMSCs-Exo. Then, functional assays were conducted to explore neurological function, pathological changes, neuron apoptosis and inflammatory factors in MCAO rats. miR-150-5p and TLR5 expression in rat brain tissues were detected. Then, gain and loss-function assays were conducted to determine the impact of exosomes, miR-150-5p and TLR5 on neurological function, pathological changes, neuron apoptosis and inflammatory factors of MCAO rats. The binding relation between miR-150-5p and TLR5 was validated. It was found that miR-150-5p expression was decreased while TLR5 level was augmented in MCAO rats. BMSCs-Exo could improve neurological function, pathological changes, decelerate neuron apoptosis and reduce inflammatory factors in MCAO rats. Enriched miR-150-5pcould enhance the protective effects of BMSCs-Exo on cerebral I/R injury. The elevated TLR5 reversed the impacts of elevated exosomal miR-150-5p on cerebral I/R injury. TLR5 was targeted by miR-150-5p. This research manifested that exosomal miR-150-5p from BMSCs exerts protective effects on cerebral I/R injury via repressing TLR5. This study provided novel therapeutic targets for the treatment of cerebral I/R injury.

Heparin alleviates LPS-induced endothelial injury by regulating the TLR4/MyD88 signaling pathway

Heparin is a commonly used in the clinic, however, Heparin's effect on endothelial injury remains unclear. The aim of the present study was to evaluate the effects and possible mechanisms of action underlying heparin treatment in lipopolysaccharide (LPS)-induced endothelial injury in vitro. TNF-α, IL-1β, IL-6 and IFN-γ levels were measured using ELISA. Cell proliferation was measured using a 5-ethynyl-2'-deoxyuridine (EdU) assay. The number of apoptotic cells and apoptotic rate were evaluated using TUNEL assays and flow cytometry, respectively. Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88) and NF-κB (p65) gene expression was evaluated using reverse transcription-quantitative PCR, whilst TLR4, MyD88 and p-NF-κB (p65) protein expression was evaluated using western blot analysis. The levels of phosphorylated NF-κB in the nucleus were evaluated using cellular immunofluorescence. Compared with those in the normal control group, TNF-α, IL-1β, IL-6 and IFN-γ levels were significantly increased in the LPS group (P<0.001). In addition, 5-ethynyl-2'-deoxyuridine (EdU)-positive cells were significantly increased and apoptosis was significantly decreased (P<0.001). TLR4, MyD88 and NF-κB (p65) expression was also significantly increased (P<0.001). Compared with those in the LPS group, following heparin treatment, TNF-α, IL-1β, IL-6 and IFN-γ levels were significantly decreased (P<0.05), whilst the number of EdU-positive cells was significantly increased and the level of apoptosis was significantly decreased (P<0.05). TLR4, MyD88 and NF-κB (p65) expression was also significantly decreased by heparin in a dose-dependent manner (P<0.001). Small interfering RNA-TLR4 transfection exerted similar effects to those mediated by heparin in alleviating endothelial injury. In conclusion, heparin suppressed LPS-induced endothelial injury through the regulation of TLR4/MyD88/NF-κB (p65) signaling in vitro.

Exploring the Mechanism of Indigo Naturalis in the Treatment of Ulcerative Colitis Based on TLR4/MyD88/NF-κB Signaling Pathway and Gut Microbiota

Background: Clinical trials have proven that indigo naturalis is a candidate drug for treating ulcerative colitis (UC), but its therapeutic mechanism is still unclear.

Purpose: This study aimed to evaluate the protective effect and mechanism of indigo naturalis to treat mice with dextran sulfate sodium (DSS)-induced UC.

Methods: DSS-induced UC mice were treated with indigo naturalis (200 mg/kg), indigo (4.76 mg/kg), and indirubin (0.78 mg/kg) for 1 week. The anti-UC mechanism of indigo naturalis was studied by pathological section, inflammatory factor, western blot, and 16S rRNA sequencing.

Results: According to body weight change, disease activity index, and colon length, indigo naturalis had the strongest anti DSS-induced UC effect, followed by indirubin and indigo. Pathological section showed that indigo naturalis, indigo, and indirubin could reduce the infiltration of inflammatory cells, increase the secretion of intestinal mucus, and repair the intestinal mucosa. Indigo naturalis, indigo, and indirubin could reduce IL-1β,IL-6, and TNF-α by inhibiting TLR4/MyD88/NF-κB signal transduction. Indigo naturalis and indigo could also reduce IgA and IgG both in serum and colon tissue. In addition, indigo naturalis, indigo, and indirubin could adjust the gut microbiota structure of DSS-induced UC mice, reducing the ratio of Firmicutes/Bacteroidetes and increasing the abundance of probiotics.

Conclusion: Indigo and indirubin are one of the main anti-UC components of indigo naturalis. INN could regulate intestinal flora, reduce inflammation, repair intestinal mucosa, and improve the physiological status of DSS-induced UC mice and its anti-UC mechanism may be involved in inhibiting TLR4/MyD88/NF-κB signal transduction.

Targeting Common Signaling Pathways for the Treatment of Stroke and Alzheimer's: a Comprehensive Review

Neurodegenerative diseases such as stroke and Alzheimer's disease (AD) are two inter-related disorders that affect the neurons in the brain and central nervous system. Alzheimer's is a disease by undefined origin and causes. Stroke and its most common type, ischemic stroke (IS), occurs due to the blockade of cerebral blood vessels. As an important feature, both of disorders are associated with irreversible damages to the brain and nervous system. In this regard, finding common signaling pathways and the same molecular origin between these two diseases may be a promising way for their solution. On the basis of literature appraisal, the most common signaling cascades implicated in the pathogenesis of AD and stroke including notch, autophagy, inflammatory, and insulin signaling pathways were reviewed. Furthermore, current therapeutic strategies including natural and synthetic pharmaceuticals aiming modulation of respective signaling factors were scrutinized to ameliorate neural deficits in AD and stroke. Taken together, digging deeper in the common connections and signal targeting can be greatly helpful in understanding and unified treating of these disorders.

Genistein Attenuates Isoflurane-Induced Neuroinflammation by Inhibiting TLR4-Mediated Microglial-Polarization in vivo and in vitro

Background

Isoflurane, a widely used anesthetic in surgery, has been found to induce neurotoxicity. In parallel, genistein is thought to attenuate isoflurane-induced neurotoxicity, although underlying molecular mechanisms are still unclear. In this study, we studied the protective effects of genistein on isoflurane-induced neuroinflammation in rats and BV2 cells.

Methods

Sprague-Dawley rat pups were exposed to 0.75% isoflurane for 6 hours at postnatal day 7 (P7), and genistein (20, 40, or 80 mg/kg/day) or saline administered from P3 to P15. Hippocampal single-cell suspensions were prepared and apoptosis analyzed by flow cytometry. mRNA expression was determined by RT-qPCR, while protein expression was assessed using Western blot, immunochemistry and immunofluorescence. TLR4 was knocked-out in BV2 cells through CRISPR-Cas9.

Results

Genistein treatment reduced isoflurane-induced apoptosis and inflammation in rat hippocampus. Importantly, genistein promoted M2 and suppressed M1 microglia polarization in rat hippocampus after stimulation with isoflurane. In addition, genistein reduced isoflurane-induced protein expression levels of TLR4, MyD88, TRAF6, p-TAK1, p-p38, p-ERK, p-IκBα and p-NF-κB in rat hippocampus. In BV2 cells exposed to isoflurane, genistein treatment decreased IL-1β, TNF-α, IL-6 and IL-8 mRNA expressions, promoted M2 and suppressed M1 microglia polarization. Similarly, genistein also decreased TLR4 protein levels in isoflurane-induced BV2 cells. However, genistein did not affect CD16, iNOS, CD206 and Arg1 protein levels in TLR4-KO BV2 cells exposed to isoflurane.

Conclusion

Genistein attenuates isoflurane-induced neurotoxicity by inhibiting TLR4-mediated microglial inflammation in vivo and in vitro.

Restoration of early deficiency of axonal guidance signaling by guanxinning injection as a novel therapeutic option for acute ischemic stroke

Despite of its high morbidity and mortality, there is still a lack of effective treatment for ischemic stroke in part due to our incomplete understanding of molecular mechanisms of its pathogenesis. In this study, we demonstrate that SHH-PTCH1-GLI1-mediated axonal guidance signaling and its related neurogenesis, a central pathway for neuronal development, also plays a critical role in early stage of an acute stroke model. Specifically, in vivo, we evaluated the effect of GXNI on ischemic stroke mice via using the middle cerebral artery embolization model, and found that GXNI significantly alleviated cerebral ischemic reperfusion (I/R) injury by reducing the volume of cerebral infarction, neurological deficit score and cerebral edema, reversing the BBB permeability and histopathological changes. A combined approach of RNA-seq and network pharmacology analysis was used to reveal the underlying mechanisms of GXNI followed by RT-PCR, immunohistochemistry and western blotting validation. It was pointed out that axon guidance signaling pathway played the most prominent role in GXNI action with Shh, Ptch1, and Gli1 genes as the critical contributors in brain protection. In addition, GXNI markedly prevented primary cortical neuron cells from oxygen-glucose deprivation/reoxygenation damage in vitro, and promoted axon growth and synaptogenesis of damaged neurons, which further confirmed the results of in vivo experiments. Moreover, due to the inhibition of the SHH-PTCH1-GLI1 signaling pathway by cyclopropylamine, the effect of GXNI was significantly weakened. Hence, our study provides a novel option for the clinical treatment of acute ischemic stroke by GXNI via SHH-PTCH1-GLI1-mediated axonal guidance signaling, a neuronal development pathway previously considered for after-stroke recovery.

CUEDC2 ablation enhances the efficacy of mesenchymal stem cells in ameliorating cerebral ischemia/reperfusion insult

Mesenchymal stem cell (MSC) therapy has been reported to be a promising therapeutic option for cerebral ischemia/reperfusion (I/R) insult. However, the poor survival rate of engrafted MSCs under unfavorable cerebral I/R-induced microenvironment inhibits their efficiency during clinical application. CUE domain-containing 2(CUECD2) exhibits its protective role on cardiomyocytes by mediating the antioxidant capacity. Our study explored the functional role of CUEDC2 in cerebral I/R challenge and determined whether CUECD2-modified MSCs could improve the efficacy of treatment of the insulted neurons. We also evaluated the possible mechanisms involved in cerebral I/R condition. Cerebral I/R stimulation suppressed CUEDC2 levels in brain tissues and neurons. siRNA-CUEDC2 in neurons significantly inhibited cerebral I/R-induced apoptosis and oxidative stress levels in vitro. Moreover, siRNA-CUEDC2 in the MSCs group remarkably enhanced the therapeutic efficacies in cerebral I/R-induced neuron injury and brain tissue impairment when compared to the non-genetic MSCs treatment group. At the molecular level, siRNA-CUEDC2 in MSCs markedly enhanced its antioxidant and anti-inflammatory effect in co-cultured neurons by upregulating glutathione peroxidase 1 (GPX1) expression levels while suppressing NF-kB activation. These findings provide a novel strategy for the utilization of MSCs to promote cerebral ischemic stroke outcomes.

Experimental pretreatment with YES-10®, a plant extract rich in scutellarin and chlorogenic acid, protects hippocampal neurons from ischemia/reperfusion injury via antioxidant role

Erigeron annuus (L.) PERS. (EALP) and Clematis mandshurica RUPR. (CMR) have been used in traditional remedies due to their medicinal effects. Recently, we reported that pretreatment with 200 mg/kg of YES-10^® (a combination of extracts from leaves of EALP and CMR) displayed neuroprotective effects against brain ischemia and reperfusion injury. The present study analyzed the major ingredients of YES-10^® and investigated whether neuroprotection from YES-10^® was dependent upon antioxidant effects in the cornu ammonis 1 (CA1) field in the gerbil hippocampus, after transient forebrain ischemia for 5 min. YES-10^® was demonstrated to predominantly contain scutellarin and chlorogenic acid. Pretreatment with YES-10^® significantly increased protein levels and the immunoreactivity of copper/zinc-superoxide dismutase (SOD1) and manganese-superoxide dismutase (SOD2) was in the pyramidal neurons of the hippocampal CA1 field when these were examined prior to transient ischemia induction. The increased SODs in CA1 pyramidal neurons following YES-10^® treatment were maintained after ischemic injury. In this case, the CA1 pyramidal neurons were protected from ischemia-reperfusion injury. Oxidative stress was significantly attenuated in the CA1 pyramidal neurons, and this was determined by 4-hydroxy-2-nonenal immunohistochemistry and dihydroethidium histofluorescence staining. Taken together, the results indicated that YES-10^® significantly attenuated transient ischemia-induced oxidative stress and may be utilized for developing a protective agent against ischemic insults.

Syringin exerts neuroprotective effects in a rat model of cerebral ischemia through the FOXO3a/NF-κB pathway

Inflammation plays an important role in the pathogenesis of cerebral ischemia. Syringin (SYR) is an active substance isolated from Acanthopanax senticosus plants, and possesses anti-inflammatory and neuroprotective properties. However, its effects on cerebral ischemic injury, as well as the underlying molecular events, are still unclear. The purpose of this study was to investigate the effect of SYR in a rat model of cerebral ischemia and address the related molecular mechanism. A middle cerebral artery occlusion/reperfusion model (MCAO) was used to simulate ischemic injury. SYR treatment clearly reduced the infarct volume, decreased cerebral water content, improved the neurological score, and attenuated neuronal death. Moreover, SYR decreased the expression of NF-κB, IL-1β, IL-6, TNF-α, and MPO, promoted FOXO3a phosphorylation and cytoplasmic retention, and inhibited the nuclear translocation of NF-κB. FOXO3a knockdown by RNA interference significantly prevented SYR-induced inhibition of NF-κB-mediated inflammation. Confocal microscopy revealed that SYR reduced NF-κB translocation to the nucleus, and FOXO3a silencing reversed this effect. Finally, immunofluorescence and CO-IP experiments showed that SYR promoted the interaction between FOXO3a and NF-κB. In conclusion, SYR exerted a protective effect against brain I/R injury by reducing the inflammation accompanying cerebral ischemia. This effect was mediated by the FOXO3a /NF-κB pathway.

The Protective Effects and Potential Mechanisms of Ligusticum chuanxiong: Focus on Anti-Inflammatory, Antioxidant, and Antiapoptotic Activities

Ligusticum chuanxiong (LC) is a Chinese materia medica which is widely used in clinical settings to treat headaches, blood extravasation, and arthritis. Recent studies demonstrate that LC possesses versatile pharmacological functions, including antiatherosclerosis, antimigraine, antiaging, and anticancer properties. Moreover, LC also shows protective effects in the progression of different diseases that damage somatic cells. Oxidative stress and inflammation, which can induce somatic cell apoptosis, are the main factors associated with an abundance of diseases, whose progresses can be reversed by LC. In order to comprehensively review the molecular mechanisms associated with the protective effects of LC, we collected and integrated all its related studies on the anti-inflammatory, antioxidant, and antiapoptotic effects. The results show that LC could exhibit the mentioned biological activities by modulating several signaling pathways, specifically the NF-κB, Nrf2, protein kinase, and caspase-3 pathways. In future investigations, the pharmacokinetic properties of bioactive compounds in LC and the signaling pathway modulation of LC could be focused.

The Combination of Astragalus membranaceus and Ligustrazine Protects Against Thrombolysis-Induced Hemorrhagic Transformation Through PKCδ/Marcks Pathway in Cerebral Ischemia Rats

Astragalus membranaceus (Ast) and ligustrazine (Lig) have a protective effect on lower hemorrhagic transformation induced by pharmaceutical thrombolysis. The cerebral ischemia rat model was induced with autologous blood clot injections. A combination of Ast and Lig, or a protein kinase C delta (PKCδ) inhibitor—rottlerin, or a combination of Ast, Lig, and rottlerin was administered immediately after recombinant tissue plasminogen activator injection. The cerebral infarct area, neurological deficits, cerebral hemorrhage status, neuronal damage and tight junctions’ changes in cerebral vessels, and the messenger RNA and protein levels of PKCδ, myristoylated alanine-rich C kinase substrate (Marcks), and matrix metallopeptidase 9 (MMP9) were determined after 3 h and 24 h of thrombolysis. The ultrastructure of the neuronal damage and tight junctions was examined under a transmission electron microscope. The expression levels of PKCδ, Marcks, and MMP9 were assessed by immunohistochemistry, western blot, and quantitative real-time polymerase chain reaction . Administration of Ast and Lig not only significantly decreased neurological deficit scores, infarct volumes, and cerebral hemorrhage but also inhibited the disruption due to neuronal dysfunction and the tight junction integrity in the cerebral vessel. Treatment with a combination of Ast and Lig effectively protected ischemia-induced microhemorrhage transformation through PKCδ/Marcks pathway suppression.

The intranasal administration of Carthamus tinctorius L. extract/phospholipid complex in the treatment of cerebral infarction via the TNF-α/MAPK pathway

Carthamus tinctorius L.(Safflower), a herbal formula from Traditional Chinese Medicine (TCM), has been widely used for the treatment of cardio-cerebrovascular diseases, particularly cerebral infarction (CI) or cerebral ischemia-reperfusion injury. However, we know very little about the specific mechanisms associated with the therapeutic effect of Safflower on CI. In this study, we used a network pharmacology-based approach, together with rat model of CI, to gain more insight into of such mechanisms. Our analysis showed that Safflower contains 52 active compounds that target 247 genes, which were also cross-referenced with 299 genes associated with CI. Consequently, we identified 52 target genes in Safflower that were associated with CI. These 52 target genes were analyzed by gene ontology (GO) enrichment analysis, leading to the identification of 1491 biological process items, 90 molecular function items and 19 cell assembly items. Eighty-nine pathways were generated by KEGG enrichment (P < 0.05). Next, we investigated the effect of the extract of safflower (ES) and Safflower extract phospholipid complex (ESPC), delivered via the nasal route, on an animal model of the middle cerebral artery occlusion (MCAO). Our data confirmed that Safflower was able to treat CI by the regulating the TNF-α/MAPK pathway via CASP3. The therapeutic effect of ES and ESPC on CI acts by improving the circulation of blood in the central nervous system, reducing the inflammatory reaction, inhibiting apoptosis, and by protecting brain nerve cells from injury.

Ethanol extracts from Ilex pubescens promotes cerebral ischemic tolerance via modulation of TLR4-MyD88/TRIF signaling pathway in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pubescent Holly Root is the dry root of Ilex pubescens Hook. et Arn. It is clinically using in the treatment for stroke and coronary artery disease. It remains unclear whether the ethanol extracts of Ilex pubescens(IPEE) treatment can promote cerebral ischemic tolerance (CIT) and exert endogenous neuroprotective effects and thus to alleviate the nerve injury caused by the subsequent persistent cerebral ischemic attacks.

AIM OF THE STUDY

To investigate the effects of IPEE on CIT and its underlying molecular mechanisms.

MATERIALS AND METHODS

Adult male Wistar rats were used in the present study. The bilateral common carotid arteries were blocked for 10 min followed a subsequent reperfusion to create the cerebral ischemic preconditioning (CIP); After 3 days post CIP, rats were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R)-injury. Rats were continuously fed with IPEE for 5 days throughout the experiment period at the dose of 100 mg/kg and 200 mg/kg, respectively. Then, the brain infarct volume, histopathology, neurological deficits, and the gene/protein expression related with the TLR4-MyD88/TRIF signaling pathway were evaluated after 24 h of MCAO/R experiment.

RESULTS

IPEE pretreatment significantly reduced the cerebral infarct volume, the neurological deficit scores, and the plasma level of neuron specific enolase (NSE) at the dose of 100 mg/kg. Meanwhile, IPEE pretreatment significantly decreased the levels of inflammatory cytokines including TNF-α, IL-6, MCP-1, MIP-1α and RANTES, while it increased the levels of anti-inflammatory cytokines, such as IL-10 and TGF-β, when compared with the group with CIP treatment alone. Moreover, the effect of IPEE treatment on CIT was in a dose-dependent manner, showing as a better effect in the group pretreated with IPEE with the dose of 100 mg/kg than that in group pretreated with IPEE with the dose of 200 mg/kg. In addition, IPEE pretreatment significantly inhibited the expressions of MyD88 mRNA and the protein expression of COX-2 and NF-κBp65, while it strengthened the expressions of TRIF mRNA and protein. The effects of IPEE pretreatment on the expression of these genes were better than that in the group treated with CIP alone.

CONCLUSIONS

The present study demonstrates that IPEE pretreatment can enhance cerebral ischemic tolerance with a underlying mechanism involved in the toll-like receptor 4 (TLR4) signaling pathway through inhibiting the production of proteins or cytokines in the downstream of MyD88 and activating TRIF dependent anti-inflammatory pathways.

Curcumin alleviates OGD/R-induced PC12 cell damage via repressing CCL3 and inactivating TLR4/MyD88/MAPK/NF-κB to suppress inflammation and apoptosis

OBJECTIVES

Curcumin presents some therapeutic effects including anti-cancer and anti-inflammation. Herein, we centred on the functional role of curcumin in cerebral ischaemia injury and its potential molecular mechanisms.

METHODS

Microarray analysis was used for excavating crucial genes in cerebral ischaemia. PC12 cells were subjected to oxygen-glucose deprivation and reoxygenation (OGD/R) to imitate cerebral ischaemia/reperfusion (I/R) injury in vitro. Cell viability and apoptosis abilities were evaluated by Cell Counting Kit-8 and flow cytometry assays. qRT-PCR, Western blot and enzyme-linked immunosorbent assays were performed to assess the concentrations of related genes.

KEY FINDINGS

By enquiring GEO dataset, C-C motif chemokine ligand 3 (CCL3) was profoundly upregulated in cerebral I/R injury model. And CCL3 was found to be highly expressed in PC12 cells suffered from OGD/R. Moreover, we found that CCL3 was a potential target of curcumin in cerebral I/R injury. More importantly, the following experiments illustrated that curcumin inhibited the expression of CCL3 in OGD/R model and reduced cell apoptosis and inflammation. Moreover, high expression levels of TLR4, MyD88, p-NF-κB P65, p-P38 MAPK and p-IκBα in OGD/R model were inhibited by curcumin.

CONCLUSIONS

Our study manifested that curcumin might be a meritorious drug for the treatment of cerebral ischaemia by acting on CCL3.

Ligusticum chuanxiong exerts neuroprotection by promoting adult neurogenesis and inhibiting inflammation in the hippocampus of ME cerebral ischemia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cerebral ischemia, also known as stroke, can stimulate the proliferation and migration of endogenous neural stem cells (NSC_S) in subventricular zone of the lateral ventricle and subgranularzone of the dentate gyrus in the adult hippocampus as a defense response to damage. However, the proliferation of endogenous NSC_S is insufficient for central nervous system repair. Neurogenesis and anti-neuroinflammation are two important aspects for neuroprotection. Rhizome Ligusticum chuanxiong (LC), the dried rhizomes of Ligusticum striatum DC., has been widely used to treat stroke for over hundreds of years in Traditional Chinese Medicine.

PURPOSE

of the study: Previous reports on pharmacological mechanism of LC mainly focus on the cerebral blood flow and thrombolysis. We aim to explore whether LC provides neuroprotective effect by increasing neurogenesis and inhibiting the IL-1β, TNF-α and expressions of glial fibrillary acidic protein.

MATERIALS AND METHODS

LC extract was delivered to microsphere-embolized (ME) cerebral ischemia Wister rats to examine its neuroprotection. Body weight, neurological scores, hematoxylin-eosin staining (HE), TUNEL assay were conducted for neurological damage. Neurogenesis was evaluated by assessing the expression of Doublecortin (DCX) and neurogenic differentiation1 (NeuroD1) through immunofluorescence staining. Western blot performed to measure the protein levels of growth associated protein-43(GAP-43), glial fibrillary acidic protein (GFAP). IL-1β and TNF-α was detected by Elisa.

RESULTS

LC alleviated pathomorphological change and apoptosis of neurons in the hippocampus caused by ME surgery. Furthermore, LC significantly increased the DCX in the DG of adult rat hippocampus at 14 days after surgery. A significant upregulation of GAP-43 compared to the ME after LC was administered. Besides, LC decreased pro-inflammatory cytokine (IL-1β, TNF-α) and protein level of GFAP.

CONCLUSION

The finding suggested that LC had the ability to protect neurons by promoting the endogenous proliferation of neuroblast and production of neural differentiation factor in rats after ischemia injury. Meanwhile, LC can anti-neuroinflammation, which is important for the treatment of neuron injury. Accordingly, LC perhaps a promising medicine for neuron damage therapy after cerebral ischemia.

YES-10, A Combination of Extracts from Clematis mandshurica RUPR. and Erigeron annuus (L.) PERS., Prevents Ischemic Brain Injury in A Gerbil Model of Transient Forebrain Ischemia

: Clematis mandshurica RUPR. (CMR) and Erigeron annuus (L.) PERS. (EALP) have pharmacological effects including anti-inflammatory activity and been used in traditional medicines in Asia. However, neuroprotective effects of CMR and/or EALP extracts against brain ischemic insults have never been addressed. Thus, the aim of this study was to examine neuroprotective effects of YES-10, a combination of extracts from CMR and EALP (combination ratio, 1:1), in the hippocampus following ischemia/reperfusion in gerbils. Protection of neurons was investigated by cresyl violet staining, fluoro-jade B histofluorescence staining and immunohistochemistry for neuronal nuclei. In addition, attenuation of gliosis was studied by immunohistochemistry for astrocytic and microglial markers. Treatments with 50 or 100 mg/kg YES-10 failed to protect neurons in the hippocampus after ischemia/reperfusion injury. However, administration of 200 mg/kg YES-10 protected neurons from ischemia/reperfusion injury and attenuated reactive gliosis. These findings strongly suggest that a combination of extracts from CMR and EALP can be used as a prevention approach/drug against brain ischemic damage.

Analysis of Chuanxiong Rhizoma substrate on production of ligustrazine in endophytic Bacillus subtilis by ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry

Ligustrazine was the active ingredient of the traditional Chinese medicine Chuanxiong Rhizoma. However, the content of ligustrazine is very low. We proposed a hypothesis that ligustrazine was produced by the mutual effects between endophytic Bacillus subtilis and the Ligusticum chuanxiong Hort. This study aimed to explore whether the endophytic B. subtilis LB5 could make use of Chuanxiong Rhizoma fermentation matrix to produce ligustrazine and clarify the mechanisms of action preliminarily. Ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry analysis showed the content of ligustrazine in Chuanxiong Rhizoma was below the detection limit (0.1 ng/mL), while B. subtilis LB5 produced ligustrazine at the yield of 1.0268 mg/mL in the Chuanxiong Rhizoma-ammonium sulfate fermentation medium. In the fermented matrix, the reducing sugar had a significant reduction from 12.034 to 2.424 mg/mL, and rough protein content increased from 2.239 to 4.361 mg/mL. Acetoin, the biosynthetic precursor of ligustrazine, was generated in the Chuanxiong Rhizoma-Ammonium sulfate (151.2 mg/mL) fermentation medium. This result showed that the endophytic bacteria B. subtilis LB5 metabolized Chuanxiong Rhizoma via secreted protein to consume the sugar in Chuanxiong Rhizoma to produce a considerable amount of ligustrazine. Collectively, our preliminary research suggested that ligustrazine was the interaction product of endophyte, but not the secondary metabolite of Chuanxiong Rhizoma itself.

Anti-Neuroinflammatory Effect of Alantolactone through the Suppression of the NF-κB and MAPK Signaling Pathways

Neuroinflammation is a major cause of central nervous system (CNS) damage and can result in long-term disability and mortality. Therefore, the development of effective anti-neuroinflammatory agents for neuroprotection is vital. To our surprise, the naturally occurring molecule alantolactone (Ala) was reported to significantly inhibit tumor growth and metastasis as a result of its excellent anti-inflammatory effects. Thus, we proposed that it could also act as an anti-neuroinflammatory agent. Thus, in this study, a coculture system of BV2 cells and PC12 cells were used as an in vitro neuroinflammatory model to investigate the anti-neuroinflammatory mechanism of Ala. The results indicated that Ala downregulated the expression of proinflammatory factors by suppressing the nuclear factor kappa light-chain enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Further evaluation using a middle cerebral artery occlusion and reperfusion (MCAO/R) rat model supported the conclusion that Ala could (1) alleviate cerebral ischemia-reperfusion injury; (2) reduce neurological deficits, cerebral infarct volume, and brain edema; and (3) attenuate the apoptosis and necrosis of neurons. In sum, Ala demonstrates anti-neuroinflammatory properties that contribute to the amelioration of CNS damage, and it could be a promising candidate for future applications in CNS injury treatment.

Effect of oleic acid on induction of steatosis and cytotoxicity in BRL 3A cells

Recent studies have shown that monounsaturated oleic acid induces steatosis in cultured hepatocyte steatosis in the form of nonalcoholic fatty liver disease models in vitro. However, the underlying mechanism of steatosis development is not completely understood. Therefore, we investigated the molecular mechanism of steatosis and the role of mitogen-activated protein kinase (MAPK)/toll-like receptor 4-related protein (TLR4) expression in this study. Rat hepatocyte cells were subjected to oleic acid in different concentrations (1.2-2.4 mM) for 24 hours. The cell morphological injury index and the changes in the MAPK/TLR4 signaling pathway-related proteins were evaluated. We found that the microstructure of the cells in the oleic acid treatment group was damaged, and higher phosphorylation levels of the MAPK pathway-related proteins were detected than those in the control group. In addition, the protein expression of TLR4, sterol regulatory element-binding protein-1, and fatty acid synthase were increased in the oleic acid treatment group. Our findings demonstrate that oleic acid causes toxic damage to rat hepatocyte cells, and the MAPK/TLR4 signaling pathway plays a significant role in lipid storage.

Folic acid deficiency enhanced microglial immune response via the Notch1/nuclear factor kappa B p65 pathway in hippocampus following rat brain I/R injury and BV2 cells

Recent studies revealed that folic acid deficiency (FD) increased the likelihood of stroke and aggravated brain injury after focal cerebral ischaemia. The microglia-mediated inflammatory response plays a crucial role in the complicated pathologies that lead to ischaemic brain injury. However, whether FD is involved in the activation of microglia and the neuroinflammation after experimental stroke and the underlying mechanism is still unclear. The aim of the present study was to assess whether FD modulates the Notch1/nuclear factor kappa B (NF-κB) pathway and enhances microglial immune response in a rat middle cerebral artery occlusion-reperfusion (MCAO) model and oxygen-glucose deprivation (OGD)-treated BV-2 cells. Our results exhibited that FD worsened neuronal cell death and exaggerated microglia activation in the hippocampal CA1, CA3 and Dentate gyrus (DG) subregions after cerebral ischaemia/reperfusion. The hippocampal CA1 region was more sensitive to ischaemic injury and FD treatment. The protein expressions of proinflammatory cytokines such as tumour necrosis factor-α, interleukin-1β and interleukin-6 were also augmented by FD treatment in microglial cells of the post-ischaemic hippocampus and in vitro OGD-stressed microglia model. Moreover, FD not only dramatically enhanced the protein expression levels of Notch1 and NF-κB p65 but also promoted the phosphorylation of pIkBα and the nuclear translocation of NF-κB p65. Blocking of Notch1 with N-[N-(3, 5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester partly attenuated the nuclear translocation of NF-κB p65 and the protein expression of neuroinflammatory cytokines in FD-treated hypoxic BV-2 microglia. These results suggested that Notch1/NF-κB p65 pathway-mediated microglial immune response may be a molecular mechanism underlying cerebral ischaemia-reperfusion injury worsened by FD treatment.

Establishment and evaluation of a simulated high‑altitude hypoxic brain injury model in SD rats

This study was conducted to establish a stable hypobaric hypoxia brain injury model. SD rats were randomly separated into control and model groups, and placed outside or inside of a hypobaric chamber, respectively. Subsequent to 24 h anoxic exposure, plasma superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG) and lactate dehydrogenase (LDH) were measured using commercial biochemical kits. Hematoxylin-eosin (H&E), Nissl's and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to observe the morphology of neurons in the hippocampus. The protein expression levels of apoptotic protease activating factor-1 (Apaf-1), hypoxia inducible factor-1α (HIF-1α), caspase-3, cleaved caspase-3, Bcl-2-associated X protein (Bax) and cytochrome c (cyto-c) were detected using western blot and immunohistochemistry analyses. Hypoxic substantially induced morphological lesions in the hippocampus concomitant with the physical behavioral performance deficit. Furthermore, hypoxia markedly exacerbated the levels of MDA, LDH and GSSG, and restrained GSH (P<0.01) and SOD (P<0.05) levels compared with the control group. In addition, hypoxia significantly induced the protein expression of Apaf-1, HIF-1α, caspase-3, cleaved caspase-3, Bax and Cyto-c (P<0.01) compared with the control group. Finally, a lower number and volume of Nissl bodies were verified in the hypoxic group. TUNEL results demonstrated a greater number of apoptotic cells in the hypoxic group. The present study demonstrates a model of rat hypoxic brain injuries induced by a hypobaric chamber at 9,000 m for 24 h. Furthermore, the redox enzyme, HIF-1α and mitochondrial apoptosis-associated protein, along with H&E and Nissl's staining, may be applied to evaluate the degree of injury.

The Role of Connexin-43 in the Inflammatory Process: A New Potential Therapy to Influence Keratitis

The studies outlined in this review highlight the relationship between inflammatory signaling molecules and connexin-43 (Cx43). Gap junction (GJ) channels and hemichannels (HCs) participate in the metabolic activity between intra- and extracellular space. Some ions and small molecules are exchanged from cell to cell or cell to extracellular space to affect the process of inflammation via GJ. We analyzed the effects of signaling molecules, such as innate immunity messengers, transcription factors, LPS, cytokine, inflammatory chemokines, and MMPs, on Cx43 expression during the inflammatory process. At the same time, we found that these signaling molecules play a critical role in the pathogenesis of keratitis. Thus, we assessed the function of Cx43 during inflammatory corneal disease. Corneal healing plays an essential role in the late stage of keratitis. We found that Cx43 is involved in wound healing. Studies have shown that the decrease of Cx43 can decrease the time of healing. We also report several Cx43 mimic peptides which can inhibit the activity of Cx43 Hc to mediate the releasing of adenosine triphosphate (ATP), which may in turn influence the inflammatory process.

Isosteviol Sodium Protects Neural Cells Against Hypoxia-Induced Apoptosis Through Inhibiting MAPK and NF-κB Pathways

BACKGROUND

Stevioside, isolated from the herb Stevia rebaudiana, has been widely used as a food sweetener all over the world. Isosteviol Sodium (STV-Na), an injectable formulation of isosteviol sodium salt, has been proved to possess much greater solubility and bioavailability and exhibit protective effects against cerebral ischemia injury in vivo by inhibiting neuron apoptosis. However, the underlying mechanisms of the neuroprotective effects STV-Na are still not completely known. In the present study, we investigated the effects of STV-Na on neuronal cell death caused by hypoxia in vitro and its underlying mechanisms.

METHODS

We used cobalt chloride (CoCl₂) to expose mouse neuroblastoma N2a cells to hypoxic conditions in vitro.

RESULTS

Our results showed that pretreatment with STV-Na (20 μM) significantly attenuated the decrease of cell viability, lactate dehydrogenase release and cell apoptosis under conditions of CoCl₂-induced hypoxia. Meanwhile, STV-Na pretreatment significantly attenuated the upregulation of intracellular Ca²⁺ concentration and reactive oxygen species production, and inhibited mitochondrial depolarization in N2a cells under conditions of CoCl₂-induced hypoxia. Furthermore, STV-Na pretreatment significantly downregulated expressions of nitric oxide synthase, interleukin-1β, tumor necrosis factor-α, interleukin-6, nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) signalings in N2a cells under conditions of CoCl₂-induced hypoxia.

CONCLUSIONS

Taken together, STV-Na protects neural cells against hypoxia-induced apoptosis through inhibiting MAPK and NF-κB pathways.

MicroRNA-410 inhibition of the TIMP2-dependent MAPK pathway confers neuroprotection against oxidative stress-induced apoptosis after ischemic stroke in mice

Ischemic stroke (IS) is an acute cerebral event characterized by a high incidence rate, high disability rate as well as a high mortality. More recently, accumulative literature has provided evidence highlighting the role played by microRNAs (miRs) in the development of neurons. Hence, the aim of the present study was to investigate the neuroprotective role of miR-410 in IS. Microarray-based gene expression profiling of AMI was conducted in order to identify differentially expressed genes (DEGs) and the corresponding miRs regulating these genes. IS models were established to assess neurology on a scoring basis. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) were all subsequently assessed. The functional role of miR-410 in IS was determined based on ectopic expression, knockdown and reporter assay experiments in hippocampal neurons. The expressions of microRNA-410, TIMP2, ERK, p38MAPK, JNK were all examined accordingly. The survival rate was assessed by MTT assay, and cell cycle and apoptosis by flow cytometry. After the loss of hippocampal neurons, infarct size as well as oxidative stress injury had been detected, microarray technology revealed that TIMP2 was differentially expressed in IS and that miR-410 regulated TIMP2. Initial observations revealed elevated levels of TIMP2 expression and MDA activity, in addition to evidence obtained indicated that the MAPK pathway had been activated along with decreased SOD, GSH-Px activity and miR-410 expression in IS mice. Ectopic expression of miR-410 was observed to inactivate the MAPK pathway, TIMP2 expression and hippocampal neuron apoptosis, while elevated hippocampal neuron survival rates and cell cycle entry were detected. Furthermore, TIMP2 as a direct target gene of miR-410, was determined to be negatively regulated by miR-410, while the MAPK pathway was found to be inhibited following TIMP2 knockdown. Our results revealed that the overexpression of miR-410 could ameliorate hippocampal neuron loss, reduce infarct size and oxidative stress injury in IS mice. Taken together, the key evidence of the current study elucidated the distinct nature of the inhibitory effect on IS as a result of overexpressed miR-410 whereby the conferral of neuroprotection was observed in oxidative stress-induced apoptosis post IS through the TIMP2-dependent repression of the MAPK pathway in mice.

Oxymatrine attenuates lipopolysaccharide-induced acute lung injury by activating the epithelial sodium channel and suppressing the JNK signaling pathway

The epithelial sodium channel (ENaC) and mitogen-activated protein kinase (MAPK) pathway have been reported to be associated with the progression of acute lung injury (ALI). Oxymatrine (OMT) alone or combined with other drugs can ameliorate paraquat- or oleic acid-induced lung injury. However, the effect of OMT on lipopolysaccharide (LPS)-induced ALI remains unknown. The aim of the present study was to evaluate whether OMT can attenuate LPS-induced ALI through regulation of the ENaC and MAPK pathway using an ALI mouse model. Histological assessment of the lung and inflammatory cell counts in bronchoalveolar lavage fluid (BALF) were performed by H&E and Wright-Giemsa staining. The lung wet/dry (W/D) weight ratio and the levels of tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), ENaC subunits, and the MAPK pathway members were determined. Isolated type II rat alveolar epithelial cells were incubated with OMT 30 min before LPS stimulation to investigate the activation of ENaC and the MAPK pathway. The results showed that OMT remarkably alleviated histopathologic changes in lung and pulmonary edema, reduced inflammatory cell counts in BALF, and decreased TNF-α and CRP levels in a dose-dependent manner. OMT significantly increased the three subunits of ENaC proteins in vivo and in vitro, while it decreased p-ERK/ERK, p-p38/p38, and p-JNK/JNK ratios in vivo. However, only the JNK pathway was markedly inhibited in vitro following pretreatment with OMT. Collectively, the results suggested that OMT might alleviate LPS-induced ALI by elevating ENaC proteins and inhibiting the JNK signaling pathway.

Antidiabetic efficacy of lactoferrin in type 2 diabetic pediatrics; controlling impact on PPAR-γ, SIRT-1, and TLR4 downstream signaling pathway

The current study aims to investigate the antidiabetic efficacy of camel milk-derived lactoferrin and potential involvement of PPAR-γ and SIRT-1 via TLR-4/NFκB signaling pathway in obese diabetic pediatric population. Sixty young obese patients with type 2 diabetes were selected from the Pediatric Endocrine Metabolic Unit, Cairo University and were randomly divided among two age and sex-matched groups so as to receive either standard therapy without lactoferrin in one arm or to be treated with oral lactoferrin capsules (250 mg/day, p.o) for 3 months in the other arm. Both groups were compared to 50 control healthy volunteers. Measurements of HbA1c, lipid profile, antioxidant capacity (SOD, Nrf2), proinflammatory interleukins; (IL-1β, IL-6, IL-18), Cyclin D-1, lipocalin-2, and PPAR-γ expression levels were done at the beginning and 3 months after daily consumption of lactoferrin. The mechanistic involvement of TLR4-SIRT-1-NFκB signaling cascade was also investigated. The antidiabetic efficacy of lactoferrin was confirmed by significant improvement of the baseline levels of HbA1c, BMI and lipid profile of the obese pediatric cohort, which is evidenced by increased PPAR-γ and SIRT-1 expression. Moreover, the anti-inflammatory effect was evident by the significant decrease in serum levels of IL-1β, IL-6, IL-18, TNF-α, lipocalin 2 in type 2 diabetic post-treatment group, which corresponded by decreased NFκB downstream signaling indicators. The antioxidant efficacy was evident by stimulated SOD levels and NrF2 expression; compared with the pre-treatment group (all at P ≤ 0.001). The consumption of high concentrations of lactoferrin explains its hypoglycemic efficacy and counts for its insulin-sensitizing, anti-inflammatory and immunomodulatory effects via TLR4-NFκB-SIRT-1 signaling cascade. Recommendations on regular intake of lactoferrin could ensure better glycemic control, compared to conventional antidiabetics alone.