Modified Citrus Pectin Alleviates Cerebral Ischemia/Reperfusion Injury by Inhibiting NLRP3 Inflammasome Activation via TLR4/NF-ĸB Signaling Pathway in Microglia

Modification, biological activity, applications, and future trends of citrus fiber as a functional component: A comprehensive review

Citrus fiber, a by-product of citrus processing that has significant nutritional and bioactive properties, has gained attention as a promising raw material with extensive developmental potential in the food, pharmaceutical, and feed industries. However, the lack of in-depth understanding regarding citrus fiber, including its structure, modification, mechanism of action, and potential applications is holding back its development and utilization in functional foods and drugs. This review explores the status of extraction methods and modifications applied to citrus fiber to augment its health benefits. With the aim of introducing readers to the potential health benefits of citrus fibers, we have placed special emphasis on their regulatory mechanisms in the context of various conditions, including type 2 diabetes mellitus, cardiovascular disease, obesity, and cancer. Furthermore, this review highlights the applications and prospects of citrus fiber, aiming to provide a theoretical basis for the utilization and exploration of this valuable resource.

Levosimendan and Dobutamin Attenuate LPS-Induced Inflammation in Microglia by Inhibiting the NF-κB Pathway and NLRP3 Inflammasome Activation via Nrf2/HO-1 Signalling

Hypovolemic shock is a circulatory failure, due to a loss in the effective circulating blood volume, that causes tissue hypoperfusion and hypoxia. This condition stimulates reactive oxygen species (ROS) and pro-inflammatory cytokine production in different organs and also in the central nervous system (CNS). Levosimendan, a cardioprotective inodilator, and dobutamine, a β1-adrenergic agonist, are commonly used for the treatment of hypovolemic shock, thanks to their anti-inflammatory and antioxidant effects. For this reason, we aimed at investigating levosimendan and dobutamine's neuroprotective effects in an "in vitro" model of lipopolysaccharide (LPS)-induced neuroinflammation. Human microglial cells (HMC3) were challenged with LPS (0.1 µg/mL) to induce an inflammatory phenotype and then treated with levosimendan (10 µM) or dobutamine (50 µM) for 24 h. Levosimendan and dobutamine significantly reduced the ROS levels and markedly increased Nrf2 and HO-1 protein expression in LPS-challenged cells. Levosimendan and dobutamine also decreased p-NF-κB expression and turned off the NLRP3 inflammasome together with its downstream signals, caspase-1 and IL-1β. Moreover, a reduction in TNF-α and IL-6 expression and an increase in IL-10 levels in LPS-stimulated HMC3 cells was observed following treatment. In conclusion, levosimendan and dobutamine attenuated LPS-induced neuroinflammation through NF-κB pathway inhibition and NLRP3 inflammasome activation via Nrf2/HO-1 signalling, suggesting that these drugs could represent a promising therapeutic approach for the treatment of neuroinflammation consequent to hypovolemic shock.

Modified Citrus Pectin (MCP) Confers a Renoprotective Effect on Early-Stage Nephropathy in Type-2 Diabetic Mice

Diabetic nephropathy (DN) is a significant global health concern with a high morbidity rate. Accumulating evidence reveals that Galectin-3 (Gal-3), a β-galactoside-binding lectin, is a biomarker in kidney diseases. Our study aimed to assess the advantageous impacts of modified citrus pectin (MCP) as an alternative therapeutic strategy for the initial and ongoing progression of DN in mice with type 2 diabetes mellitus (T2DM). The animal model has been split into four groups: control group, T2DM group (mice received intraperitoneal injections of nicotinamide (NA) and streptozotocin (STZ), T2DM+MCP group (mice received 100 mg/kg/day MCP following T2DM induction), and MCP group (mice received 100 mg/kg/day). After 4 weeks, kidney weight, blood glucose level, serum kidney function tests, histopathological structure alterations, oxidative stress, inflammation, apoptosis, and fibrosis parameters were determined in renal tissues. Our findings demonstrated that MCP treatment reduced blood glucose levels, renal histological damage, and restored kidney weight and kidney function tests. Additionally, MCP reduced malondialdehyde level and restored glutathione level, and catalase activity. MCP demonstrated a notable reduction in inflammatory and apoptosis mediators TNF-α, iNOS, TGF-βRII and caspase-3. Overall, MCP could alleviate renal injury in an experimental model of DN by suppressing renal oxidative stress, inflammation, fibrosis, and apoptosis mediators.

Dynamic Changes and Clinical Significance of Plasma Galectin-3 in Patients with Acute Ischemic Stroke Undergoing Endovascular Therapy

Purpose

Galectin-3 is a key regulator of microglial proliferation and activation and may have dual and time-dependent effects on ischemic stroke. This study aimed to prospectively investigate the dynamic changes in Galectin-3 levels in patients with acute ischemic stroke receiving endovascular therapy and its clinical significance.

Patients and Methods

A total of 105 patients with acute ischemic stroke who underwent endovascular therapy were prospectively enrolled. Plasma Galectin-3 was quantitatively detected by an enzyme-linked immunosorbent assay before the operation and at 1 day, 3 days and 7 days after the operation. A linear mixed-effect model, Pearson correlation analysis and receiver operating characteristic (ROC) curve analysis were used to evaluate the dynamic changes in the plasma Galectin-3 concentration and its relationship with clinical outcomes.

Results

Increases in plasma Galectin-3 levels at 1 day and 3 days after surgery were associated with early neurological deterioration and death (both P <0.05). Increased Galectin-3 levels before surgery and at 1 day and 3 days after surgery were associated with poor prognosis (P <0.05). Pearson correlation analysis revealed that Galectin-3 levels before surgery (r =0.318, P =0.002), at 1 day (r =0.318, P =0.001), 3 days (r =0.429, P < 0.001) and 7 days after surgery (r =0.340, P =0.001) were positively correlated with NIHSS scores. The ROC curve results showed that Galectin-3 concentration had a certain predictive value for death at 1 day (AUC=0.707, P=0.013), 3 days (AUC=0.708, P=0.016) and 7 days after the operation (AUC=0.708, P=0.016), but this predictive value was lower than that of the NIHSS score.

Conclusion

In acute ischemic stroke patients receiving endovascular therapy, an increase in the plasma Galectin-3 levels were associated with death, poor prognosis, and early neurological deterioration. Galectin-3 levels were significantly correlated with the NIHSS score and had a certain predictive value for death.

Fluoride promotes the secretion of inflammatory factors in microglia through NLRP3/Caspase-1/GSDMD pathway

It is widespread of endemic fluorosis in China, and the exposure of excessive fluoride will cause nervous system disease and activate microglia. However, the mechanism of the damage is not clear. It is well-known that NLRP3/Caspase-1/GSDMD pathway, a classic pyroptosis pathway, is widely involved in the occurrence and development of nervous system-related diseases, infectious diseases, and atherosclerotic diseases. This research aimed to explore the molecular mechanism of sodium fluoride on inflammation and pyroptosis in BV2 microglia based on the NLRP3/Caspase-1/GSDMD signaling pathway. BV2 microglia was treated with sodium fluoride at the dose of 0.25, 1, and 2 mmol/L for 24, 48, and 72 h, respectively. Cell viability, cell morphology, lactate dehydrogenase content, and related proteins and genes were examined to investigate if sodium fluoride caused damage to BV2 microglia through the pyroptosis pathway. Dithiolam (5 μmol/L), a pyroptosis inhibitor, was added for further verification. NaF could induced BV2 cells injury in a dose-dependent fashion through disrupting the integrity of cell membranes and increasing IL-1β via upregulating NLRP3, Caspase-1, and its downstream protein GSDMD. Disulfiram could improve these changes caused by NaF. In conclusion, our results suggested that NLRP3/Caspase-1/GSDMD-mediated classical pyroptosis pathway was involved in fluoride-induced BV2 microglia damage.

Therapeutic Potential of Pectin and Its Derivatives in Chronic Diseases

Non-communicable diseases (NCDs) are described as a collection of chronic diseases that do not typically develop from an acute infection, have long-term health effects, and frequently require ongoing care and therapy. These diseases include heart disease, stroke, cancer, chronic lung disease, neurological diseases, osteoporosis, mental health disorders, etc. Known synthetic drugs for the treatment or prevention of NCDs become increasingly dangerous over time and pose high risks due to side effects such as hallucination, heart attack, liver failure, etc. As a result, scientists have had to look for other alternatives that are natural products and that are known to be less detrimental and contain useful bioactive compounds. The increasing understanding of the biological and pharmacological significance of carbohydrates has helped to raise awareness of their importance in living systems and medicine, given they play numerous biological roles. For example, pectin has been identified as a class of secondary metabolites found in medicinal plants that may play a significant role in the treatment and management of a variety of NCDs. Pectin is mainly made of homogalacturonan, which is a linear polymer composed primarily of D-galacturonic acid units (at least 65%) linked in a chain by α-(1,4)-glycosidic linkages. There are also modified pectins or derivatives that improve pectin's bioavailability. Pectin is found in the cell walls of higher plants (pteridophytes, angiosperms, and gymnosperms), particularly in the middle lamella of the plant material. Citrus pectin is used in various industries. This article compiles information that has been available for years about the therapeutic importance of pectin in chronic diseases, different modes of pectin extraction, the chemistry of pectin, and the potency of pectin and its derivatives.

Anti-Apoptotic and Anti-Inflammatory Properties of Grapefruit IntegroPectin on Human Microglial HMC3 Cell Line

In this study, we investigated the beneficial effects of grapefruit IntegroPectin, derived from industrial waste grapefruit peels via hydrodynamic cavitation, on microglia cells exposed to oxidative stress conditions. Grapefruit IntegroPectin fully counteracted cell death and the apoptotic process induced by cell exposure to tert-butyl hydroperoxide (TBH), a powerful hydroperoxide. The protective effects of the grapefruit IntegroPectin were accompanied with a decrease in the amount of ROS, and were strictly dependent on the activation of the phosphoinositide 3-kinase (PI3K)/Akt cascade. Finally, IntegroPectin treatment inhibited the neuroinflammatory response and the basal microglia activation by down-regulating the PI3K- nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB)- inducible nitric oxide synthase (iNOS) cascade. These data strongly support further investigations aimed at exploring IntegroPectin's therapeutic role in in vivo models of neurodegenerative disorders, characterized by a combination of chronic neurodegeneration, oxidative stress and neuroinflammation.

Inhibition of Glial Activation and Subsequent Reduction in White Matter Damage through Supplementation with a Combined Extract of Wheat Bran, Citrus Peel, and Jujube in a Rat Model of Vascular Dementia

Vascular dementia (VaD) is the second most common type of dementia after Alzheimer's disease. In our previous studies, we showed that wheat bran extract (WBE) reduced white matter damage in a rat VaD model and improved memory in a human clinical trial. However, starch gelatinization made the large-scale preparation of WBE difficult. To simplify the manufacturing process and increase efficacy, we attempted to find a decoction containing an optimum ratio of wheat bran, sliced citrus peel, and sliced jujube (WCJ). To find an optimal ratio, the cell survival of C6 (rat glioma) cultured under hypoxic conditions (1% O2) was measured, and apoptosis was assessed. To confirm the efficacies of the optimized WCJ for VaD, pupillary light reflex, white matter damage, and the activation of astrocytes and microglia were assessed in a rat model of bilateral common carotid artery occlusion (BCCAO) causing chronic hypoperfusion. Using a combination of both searching the literature and cell survival experiments, we chose 6:2:1 as the optimal ratio of wheat bran to sliced citrus peel to sliced jujube to prepare WCJ. We showed that phytic acid contained only in wheat bran can be used as an indicator component for the quality control of WCJ. We observed in vitro that the WCJ treatment improved cell survival by reducing apoptosis through an increase in the Bcl-2/Bax ratio. In the BCCAO experiments, the WCJ-supplemented diet prevented astrocytic and microglial activation, mitigated myelin damage in the corpus callosum and optic tract, and, consequently, improved pupillary light reflex at dosages over 100 mg/kg/day. The results suggest that the consumption of WCJ can prevent VaD by reducing white matter damage, and WCJ can be developed as a safe, herbal medicine to prevent VaD.

Galectin-3 Mediates Endotoxin Internalization and Caspase-4/11 Activation in Tubular Epithelials and Macrophages During Sepsis and Sepsis-Associated Acute Kidney Injury

Besides being recognized by membrane receptor TLR4, lipopolysaccharide (LPS) can also be internalized into the cytosol and activate Caspase-4/11 pyroptotic pathways to further amplify inflammation in sepsis. The objective of this study was to investigate whether Galectin-3 (Gal3) could promote the uptake of LPS by governing RAGE or administering endocytosis, consequently activating Caspase 4/11 and mediating pyroptosis in sepsis-associated acute kidney injury (SA-AKI). By pinpointing Gal3, LPS, and EEA1 (endosome-marker) or LAMP1 (lysosome-marker) respectively, immunofluorescence discovered that Gal3 and LPS were mainly aggregated in early endosomes initially and translocated into lysosomes afterwards. In cells and animal models, Gal3 and the Caspase-4/11 pathways were simultaneously activated, and the overexpression of Gal3 could exacerbate pyroptosis, whereas inhibition of Gal3 or the knockdown of its expression could ameliorate pyroptosis, reduce the pathological changes of SA-AKI and improve the survival of the animals with SA-AKI. Silencing RAGE reduced pyroptosis in primary tubular epithelial cells (PTCs) activated by Gal3 and LPS but not in cells activated by Gal3 and outer membrane vesicles (with LPS inside), whereas pyroptosis in both was reduced by blockade of Gal3, indicating Gal3 promoted pyroptosis through both RAGE-dependent and RAGE-independent pathways. Our investigation further revealed a positive correlation between serum Gal3 and pyroptotic biomarkers IL-1 beta and IL-18 in patients with sepsis, and that serum Gal3 was an independent risk factor for mortality. Through our collective exploration, we unraveled the significant role of Gal3 in the internalization of LPS and the provocation of more intense pyroptosis, thus making it a vital pathogenic factor in SA-AKI and a possible therapeutic target. Gal3 enabled the internalization of endotoxin into endosomes and lysosomes via both RAGE-dependent (A) and RAGE-independent (B) pathways, leading to pyroptosis. The suppression of Gal3 curbed Caspase4/11 noncanonical inflammasomes and diminished sepsis and SA-AKI.

Nature's soothing solution: Harnessing the potential of food-derived polysaccharides to control inflammation

Reducing inflammation by diet is a major goal for prevention or lowering symptoms of a variety of diseases, such as auto-immune reactions and cancers. Natural polysaccharides are increasingly gaining attention due to their potential immunomodulating capacity. Structures of those molecules are highly important for their effects on the innate immune system, cytokine production and secretion, and enzymes in immune cells. Such polysaccharides include β-glucans, pectins, fucoidans, and fructans. To better understand the potential of these immunomodulatory molecules, it is crucial to enhance dedicated research in the area. A bibliometric analysis was performed to set a starting observation point. Major pillars of inflammation, such as pattern recognition receptors (PRRs), enzymatic production of inflammatory molecules, and involvement in specific pathways such as Nuclear-factor kappa-B (NF-kB), involved in cell transcription, survival, and cytokine production, and mitogen-activated protein kinase (MAPK), a regulator of genetic expression, mitosis, and cell differentiation. Therefore, the outcomes from polysaccharide applications in those scenarios are discussed.

Targeting galectin-3 in inflammatory and fibrotic diseases

Galectin (Gal)-3 is a β-galactoside-binding lectin emerging as a key player in cardiac, hepatic, renal, and pulmonary fibrosis and inflammation, respiratory infections caused by COVID-19, and neuroinflammatory disorders. Here, we review recent information highlighting Gal-3 as a relevant therapeutic target in these specific disease conditions. While a causal link was difficult to establish until now, we discuss how recent strategic breakthroughs allowed us to identify new-generation Gal-3 inhibitors with improved potency, selectivity, and bioavailability, and report their usefulness as valuable tools for proof-of-concept studies in various preclinical models of the aforementioned diseases, with emphasis on those actually in clinical stages. We also address critical views and suggestions intended to expand the therapeutic opportunities provided by this complex target.

Unveiling Plant-Based Pectins: Exploring the Interplay of Direct Effects, Fermentation, and Technological Applications in Clinical Research with a Focus on the Chemical Structure

Pectin, a plant-derived polysaccharide, possesses immense technological and biological application value. Several variables influence pectin's physicochemical aspects, resulting in different fermentations, interactions with receptors, and other functional properties. Some of those variables are molecular weight, degree of methylation and blockiness, and monosaccharide composition. Cancer cell cytotoxicity, important fermentation-related byproducts, immunomodulation, and technological application were found in cell culture, animal models, and preclinical and clinical assessments. One of the greater extents of recent pectin technological usage involves nanoencapsulation methods for many different compounds, ranging from chemotherapy and immunotherapy to natural extracts from fruits and other sources. Structural modification (modified pectin) is also utilized to enhance the use of dietary fiber. Although pectin is already recognized as a component of significant importance, there is still a need for a comprehensive review that delves into its intricate relationships with biological effects, which depend on the source and structure of pectin. This review covers all levels of clinical research, including cell culture, animal studies, and clinical trials, to understand how the plant source and pectin structures influence the biological effects in humans and some technological applications of pectin regarding human health.

Higenamine improves DSS-induced ulcerative colitis in mice through the Galectin-3/TLR4/NF-κB pathway

Ulcerative colitis (UC) is an inflammatory disease of the colon and tends to relapse. Higenamine (HG) has anti-inflammatory, antioxidant and anti-apoptotic activities. This study aimed to investigate the role of HG in the treatment of UC as well as the underlying mechanism. In vivo and in vitro models of UC were respectively established in dextran sodium sulfate (DSS)-induced mice and DSS-induced NCM460 cells. The weight and disease performance and disease activity index (DAI) of mice were recorded every day. The colon length was measured and pathological changes of colon tissues were observed by HE staining. The apoptosis of colon cells in mice was detected by Tunel assay and FITC-dextran was used to detect intestinal permeability in mice. The MPO activity and expression of tight junction proteins and Galectin-3/TLR4/NF-κB pathway related proteins in colon tissues and cells were detected by MPO assay kit and western blot. The levels of TNF-α, IL-1β, IL-6 and IL-10 in serum and cells, and levels of DAO and D-LA in serum were all detected by assay kits. The viability and apoptosis of NCM460 cells were analyzed by CCK-8 assay and flow cytometry analysis, and permeability of NCM460 monolayers was detected by TEER measurement. As a result, HG improved the weight, DAI, colon length and pathological changes of DSS-induced UC mice. HG alleviated DSS-induced colon inflammation, inhibited DSS-induced apoptosis of mouse colonic epithelial cells and restored the integrity of the mucosa barrier in mice. In addition, HG suppressed the Galectin-3/TLR4/NF-κB signaling pathway in DSS-induced UC mice. Similarly, HG improved viability and epithelial barrier function, and suppressed the apoptosis and inflammation of DSS-induced NCM460 cells by inhibiting the Galectin-3/TLR4/NF-κB signaling pathway. Galectin-3 overexpression could reverse the effect of HG on DSS-induced NCM460 cells. In conclusion, HG improved DSS-induced UC through the inactivation of Galectin-3/TLR4/NF-κB pathway in vivo and in vitro. AVAILABILITY OF DATA AND MATERIAL: The data are available from the corresponding author on reasonable request.

CB2R activation ameliorates late adolescent chronic alcohol exposure-induced anxiety-like behaviors during withdrawal by preventing morphological changes and suppressing NLRP3 inflammasome activation in prefrontal cortex microglia in mice

BACKGROUND

Chronic alcohol exposure (CAE) during late adolescence increases the risk of anxiety development. Alcohol-induced prefrontal cortex (PFC) microglial activation, characterized by morphological changes and increased associations with neurons, plays a critical role in the pathogenesis of anxiety. Alcohol exposure increases NLRP3 inflammasome expression, increasing cytokine secretion by activated microglia. Cannabinoid type 2 receptor (CB2R), an essential receptor of the endocannabinoid system, regulates microglial activation and neuroinflammatory reactions. We aimed to investigate the role of CB2R activation in ameliorating late adolescent CAE-induced anxiety-like behaviors and microglial activation in C57BL/6J mice.

METHODS

Six-week-old C57BL/6J mice were acclimated for 7 days and then were administered alcohol by gavage (4 g/kg, 25 % w/v) for 28 days. The mice were intraperitoneally injected with the specific CB2R agonist AM1241 1 h before alcohol treatment. Anxiety-like behaviors during withdrawal were assessed by open field test and elevated plus maze test 24 h after the last alcohol administration. Microglial activation, microglia-neuron interactions, and CB2R and NLRP3 inflammasome-related molecule expression in the PFC were measured using immunofluorescence, immunohistochemical, qPCR, and Western blotting assays. Microglial morphology was evaluated by Sholl analysis and the cell body-to-total cell size index. Additionally, N9 microglia were activated by LPS in vitro, and the effects of AM1241 on NLRP3 and N9 microglial activation were investigated.

RESULTS

After CAE, mice exhibited severe anxiety-like behaviors during withdrawal. CAE induced obvious microglia-neuron associations, and increased expression of microglial activation markers, CB2R, and NLRP3 inflammasome-related molecules in the PFC. Microglia also showed marked filament retraction and reduction and cell body enlargement after CAE. AM1241 treatment ameliorated anxiety-like behaviors in CAE model mice, and it prevented microglial morphological changes, reduced microglial activation marker expression, and suppressed the microglial NLRP3 inflammasome activation and proinflammatory cytokine secretion induced by CAE. AM1241 suppressed the LPS-induced increase in NLRP3 inflammasome-related molecules, IL-1β release, and M1 phenotype markers (iNOS and CD86) in N9 cell, which was reversed by CB2R antagonist treatment.

CONCLUSIONS

CAE caused anxiety-like behaviors in late adolescent mice at least partly by inducing microglial activation and increasing microglia-neuron associations in the PFC. CB2R activation ameliorated these effects by preventing morphological changes and suppressing NLRP3 inflammasome activation in PFC microglia.

Treatment of Ischemic Stroke With Wenyang Huayu Formula: Network Pharmacology Analysis and Experimental Validation

Context: Wenyang Huayu formula (WYHYF) is a prescription useful for treating stroke. Objective: To evaluate the mechanism of WYHYF in the treatment of ischemic stroke. Materials and methods: Network pharmacology analysis was performed to identify the chemical components and potential targets of WYHYF related to cerebral ischemia-reperfusion. The Cytoscape software and STRING database were used to draw a “drug component target disease” and protein interaction network diagram, respectively. Metascape database was used for gene enrichment analysis, and Autodock vina software was used for molecular docking to determine the pathways and targets of WYHYF. Finally, the pathways and targets were verified in vivo in rats. Results: We identified 277 drug targets and 3777 disease targets of WYHYF. Enrichment analysis of the Kyoto Encyclopedia of Genes and Genomes pathways yielded 222 entries. The results of molecular docking showed that the core components and core proteins had a good binding ability. Validation analysis in the animal model indicated that stigmasterol, C-homoerythrin, luteolin, and other components in WYHYF influence the effects of the Toll-like receptor 4(TLR4)/NF-κB signal pathway on IL-6, IL-1β, and tumor necrosis factor-alpha-α and exert neuroprotective effects, relieve reperfusion injury, and inhibit apoptosis and inflammation. Discussion and conclusions: WYHYF affects ischemic stroke through the interactions of multiple components, targets, and pathways. The mechanism may involve the TLR4/NF-κB signal pathway to inhibit apoptosis, reduce inflammation, and promote angiogenesis.