Poncirin suppresses lipopolysaccharide (LPS)-induced microglial inflammation and ameliorates brain ischemic injury in experimental stroke in mice

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.

EP1 receptor: Devil in emperors coat

EP1 receptor belongs to prostanoid receptors and is activated by prostaglandin E2. The receptor performs contrasting functions in central nervous system (CNS) and other tissues. Although the receptor is neurotoxic and proapoptotic in CNS, it has also been reported to act in an antiapoptotic manner by modulating cell survival, proliferation, invasion, and migration in different types of cancers. The receptor mediates its neurotoxic effects by increasing cytosolic Ca2+ levels, leading to the activation of its downstream target, protein kinase C, in different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, amyotrophic lateral sclerosis, and epilepsy. Antagonists ONO-8713, SC51089, and SC51322 against EP1 receptor ameliorate the neurotoxic effect by attenuating the neuroinflammation. The receptor also shows increased expression in different types of cancers and has been found to activate different signaling pathways, which lead to the development, progression, and metastasis of different cancers. The receptor stimulates the cell survival pathway by phosphorylating the AKT and PTEN (phosphatase and tensin homolog deleted on chromosome 10) signaling pathways. Although there are limited studies about this receptor and not a single clinical trial has been targeting the EP1 receptor for different neurological disorders or cancer, the receptor is appearing as a potential candidate for therapeutic targets. The aim of this article is to review the recent progress in understanding the pathogenic roles of EP1 receptors in different pathological conditions.

Bioactive Chemical Constituents and Pharmacological Activities of Ponciri Fructus

Ponciri Fructus is a crude drug obtained from the dried immature fruits of Poncirus trifoliata (L). Raf. (Syn. Citrus trifoliata L.). This study aims to compile and analyze the ethnomedicinal uses, bioactive constituents, and pharmacological activities of Ponciri Fructus. Various online bibliographic databases namely, SciFinder, PubMed, Google Scholar, and Web of Science were used for collecting information on traditional uses, biological activities, and bioactive constituents. Concerning ethnomedicinal uses, Ponciri Fructus is extensively used in traditional Korean, Chinese, and Kampo medicines to mitigate allergic reactions, inflammation, edema, digestive complications, respiratory problems, spleen-related problems, liver complications, neuronal pain, hyperlipidemia, rheumatoid arthritis, cardiovascular problems, hernia, sinusitis, and insomnia. Several studies have shown that Ponciri Fructus is a major source of diverse classes of bioactive compounds namely flavonoids, terpenoids, coumarins, phytosterols, and alkaloids. Several in vivo and in vitro pharmacological activity evaluations such as antidiabetic, anti-obesity, anti-inflammatory, antiallergic, antimelanogenic, gastroprotective, anticancer, and neuroprotective effects have been conducted from Ponciri Fructus. However, scientific investigations focusing on bioassay-guided isolation and identification of specific bioactive constituents are limited. Therefore, an in-depth scientific investigation of Ponciri Fructus focusing on bioassay-guided isolation, mechanism based pharmacological studies, pharmacokinetic studies, and evaluation of possible toxicities is necessary in the future.

A monoamine oxidase B inhibitor ethyl ferulate suppresses microglia-mediated neuroinflammation and alleviates ischemic brain injury

Microglia are the resident macrophages in the brain, which play a critical role in post-stroke neuroinflammation. Accordingly, targeting neuroinflammation could be a promising strategy to improve ischemic stroke outcomes. Ethyl ferulate (EF) has been confirmed to possess anti-inflammatory properties in several disease models, including acute lung injury, retinal damage and diabetes-associated renal injury. However, the effects of EF on microglial activation and the resolution of post-stroke neuroinflammation remains unknown. Here, we found that EF suppressed pro-inflammatory response triggered by lipopolysaccharide (LPS) stimulation in primary microglia and BV2 cell lines, as well as post-stroke neuroinflammation in an in vivo transient middle cerebral artery occlusion (tMCAO) stroke model in C57BL/6 mice, consequently ameliorating ischemic brain injury. Furthermore, EF could directly bind and inhibit the activity of monoamine oxidase B (MAO-B) to reduce pro-inflammatory response. Taken together, our study identified a MAO-B inhibitor, Ethyl ferulate, as an active compound with promising potentials for suppressing post-stroke neuroinflammation.

Ponciri Fructus Immaturus ethanol extract attenuates septic shock through inhibition of the STAT1 signaling pathway

Sepsis is a systemic inflammatory disease to infections and results in tissue damage and multiple organ failure. Ponciri Fructus Immaturus (PFI) is widely used in traditional medicine for allergic inflammation and gastrointestinal disorders. However, the effect of PFI on sepsis is still unknown. This study investigated the anti-inflammatory and antiseptic effects of PFI ethanol extract (PFIE) in LPS-stimulated J774 macrophages and mice with CLP- or LPS-induced sepsis, respectively. PFIE attenuates the LPS-induced production of the proinflammatory mediator NO by inhibiting the expression of iNOS in J774 cells. Real-time RT-PCR data and ELISA showed that the mRNA and protein levels of TNF-α, IL-1β, and IL-6 increased in LPS-stimulated J774 cells. However, this induction was significantly suppressed in PFIE pre-treated J774 cells. We also found that PFIE administration increased the survival rate of mice with LPS- and CLP-induced sepsis. Decreased serum levels of AST, ALT, and CK were observed after administration of PFIE, which was associated with reduced production of proinflammatory factors, such as NO, TNF-α, IL-1β, and IL-6. Moreover, PFIE suppressed the phosphorylation and nuclear translocation of STAT1 in LPS-stimulated J774 cells, suggesting that PFIE can inhibit LPS- and CLP-induced septic shock by suppressing the STAT1 activation. These findings provide the potential therapeutic relevance of PFIE in treating acute inflammatory disease.

Poncirin ameliorates cardiac ischemia-reperfusion injury by activating PI3K/AKT/PGC-1α signaling

Poncirin, a flavonoid glycoside derivative extracted from the fruits of Poncirus trifoliata (trifoliate orange or Chinese bitter orange), has a variety of documented bioactivities, including anti-tumor, anti-inflammatory, and antioxidant effects. Oxidative stress is a major underlying factor in the pathogenesis of cardiac ischemia-reperfusion (I/R) injury. Therefore, we investigated the protective efficacy of poncirin on primary cardiomyocytes subjected to anoxia-reoxygenation (A/R) injury in vitro, and on rat hearts subjected to ischemia-reperfusion (I/R) injury in vivo. Poncirin pretreatment enhanced cardiomyocyte survival, inhibited A/R-induced oxidative stress by upregulating cellular antioxidant capacity, suppressed mitochondrial depolarization, and ultimately inhibited apoptosis. Similarly, systemic poncirin treatment significantly reduced cardiomyocyte apoptosis and infarct size in rat hearts. In addition, activity of the PI3K/AKT/PGC-1α pathway was significantly increased by poncirin pretreatment in both A/R and I/R injury models, while PI3K and PGC-1α inhibitors abolished all poncirin related effects, suggesting that this pathway is essential for the cardioprotective effects of poncirin. Pretreatment with the PGC-1α inhibitor reversed effects of poncirin without affecting p-AKT expression, indicating that PGC-1α is downstream of AKT. In conclusion, both in vitro and in vivo studies suggested that poncirin alleviates cardiac ischemia-reperfusion injury by mitigating oxidative stress, which is dependent on activation of the PI3K/AKT/PGC-1α signaling pathway.

Omnifarious fruit polyphenols: an omnipotent strategy to prevent and intervene diabetes and related complication?

Diabetes mellitus is a metabolic syndrome which cannot be cured. Recently, considerable interest has been focused on food ingredients to prevent and intervene in complications of diabetes. Polyphenolic compounds are one of the bioactive phytochemical constituents with various biological activities, which have drawn increasing interest in human health. Fruits are part of the polyphenol sources in daily food consumption. Fruit-derived polyphenols possess the anti-diabetic activity that has already been proved either from in vitro studies or in vivo studies. The mechanisms of fruit polyphenols in treating diabetes and related complications are under discussion. This is a comprehensive review on polyphenols from the edible parts of fruits, including those from citrus, berries, apples, cherries, mangoes, mangosteens, pomegranates, and other fruits regarding their potential benefits in preventing and treating diabetes mellitus. The signal pathways of characteristic polyphenols derived from fruits in reducing high blood glucose and intervening hyperglycemia-induced diabetic complications were summarized.

Dextromethorphan Dampens Neonatal Astrocyte Activation and Endoplasmic Reticulum Stress Induced by Prenatal Exposure to Buprenorphine

Prenatal exposure to buprenorphine renders offspring vulnerable to cerebral impairments. In this study, our data demonstrate, for the first time, that prenatal exposure to buprenorphine escalates astrocyte activation concurrent with indications of endoplasmic reticulum (ER) stress in the hippocampi of neonates, and this can be prevented by the coadministration of dextromethorphan with buprenorphine. Furthermore, dextromethorphan can inhibit the accumulation of GPR37 in the hippocampus of newborns caused by buprenorphine and is accompanied by the proapoptotic ER stress response that involves the procaspase-3/CHOP pathway. Primary astrocyte cultures derived from the neonates of the buprenorphine group also displayed aberrant ER calcium mobilization and elevated basal levels of cyclooxygenase-2 (COX-2) at 14 days in vitro while showing sensitivity to lipopolysaccharide-activated expression of COX-2. Similarly, these long-lasting defects in the hippocampus and astrocytes were abolished by dextromethorphan. Our findings suggest that prenatal exposure to buprenorphine might instigate long-lasting effects on hippocampal and astrocytic functions. The beneficial effects of prenatal coadministration of dextromethorphan might be, at least in part, attributed to its properties in attenuating astrocyte activation and hippocampal ER stress in neonates.

Anhydroexfoliamycin, a Streptomyces Secondary Metabolite, Mitigates Microglia-Driven Inflammation

Anhydroexfoliamycin, a secondary metabolite from Streptomyces, has shown antioxidant properties in primary cortical neurons reducing neurodegenerative hallmarks diseases, both in vitro and in vivo models. Activated microglia, in the central nervous system, plays a crucial role in neuroinflammation and is associated with neurodegeneration. Therefore, the aim of the present study was to determine the anti-inflammatory and antioxidant potential of the anhydroexfoliamycin over microglia BV2 cells. Neuroinflammation was simulated by incubation of microglia cells in the presence of lipopolysaccharide to activate proinflammatory transduction pathways. Moreover, a coculture of neuron SH-SY5Y and microglia BV2 cells was used to evaluate the neuroprotective properties of the Streptomyces metabolite. When microglia cells were preincubated with anhydroexfoliamycin, proinflammatory pathways, such as the translocation of the nuclear factor κB, the phosphorylation of c-Jun N-terminal kinase, and the inducible nitric oxide synthase expression, were inhibited. In addition, intracellular reactive oxygen species generation and the liberation of nitric oxide, interleukin 6, and tumor necrosis factor α were also decreased. Besides, the Streptomyces-derived compound showed antioxidant properties promoting the translocation of the factor erythroid 2-related factor 2 and protecting the SH-SY5Y cells from the neurotoxic mediators released by activated microglia. The effects of this compound were at the same level as the immunosuppressive drug cyclosporine A. Therefore, these results indicate that anhydroexfoliamycin is a promising tool to control microglia-driven inflammation with therapeutic potential in neuroinflammation.