Resveratrol inhibits high-glucose-induced inflammatory "metabolic memory" in human retinal vascular endothelial cells through SIRT1-dependent signaling

Beneficial effects of resveratrol on diabetes mellitus and its complications: focus on mechanisms of action

Diabetes mellitus (DM) is a significant global health issue, associated with various microvascular and macrovascular complications that significantly impair patients' quality of life as well as healthspan and lifespan. Despite the availability of several anti-diabetic medications with different mechanisms of action, there remains no definite curative treatment. Hence, discovering new efficient complementary therapies is essential. Natural products have received significant attention due to their advantages in various pathological conditions. Resveratrol is a natural polyphenol that possesses antioxidant and anti-inflammatory properties, and its efficacy has been previously investigated in several diseases, including DM. Herein, we aimed to provide a holistic view of the signaling pathways and mechanisms of action through which resveratrol exerts its effects against DM and its complications.

Resveratrol Enhances the Efficacy of Combined BM-MSCs Therapy for Rat Spinal Cord Injury via Modulation of the Sirt-1/NF-κB Signaling Pathway

Spinal cord injury (SCI) represents a severe trauma to the central nervous system, resulting in significant disability and imposing heavy burdens on families and society. Pathophysiological changes following SCI often trigger secondary injuries that complicate treatment. Bone marrow mesenchymal stem cells (BM-MSCs) have become a focal point of research due to their multifunctionality and self-renewal capabilities; however, their survival and neuroprotective functions are compromised in inflammatory environments. Resveratrol, known for its anti-inflammatory, anti-aging, and anti-oxidative stress properties, has been extensively studied. This research focuses on the anti-inflammatory effects of resveratrol post-SCI and its combined application with BM-MSCs to treat rat spinal cord injuries, exploring both efficacy and mechanisms. In vivo experiments investigated changes in the Sirt-1 signaling pathway post-SCI, while in vitro studies examined the effects of resveratrol on BM-MSCs under inflammatory conditions. The assessment included recovery of motor function, neuronal survival, and apoptosis in SCI rats treated with resveratrol alone or in combination with BM-MSCs. Findings reveal a correlation between Sirt-1 and inflammation signaling pathways post-injury. Resveratrol significantly enhanced the survival and efficacy of BM-MSCs in inflammatory environments by upregulating Sirt-1 and downregulating NF-κB and other inflammatory markers, thereby reducing apoptosis. Combined treatment with resveratrol and BM-MSCs showed superior outcomes in motor function recovery and neuronal survival compared to treatment with BM-MSCs alone. This study offers a novel therapeutic strategy for SCI, enhancing stem cell survival and function through modulation of the Sirt-1/NF-κB pathway, providing a theoretical and experimental foundation for clinical applications.

Effect of Resveratrol on MMP-2 Expression in Scleral Fibroblasts: An In Vitro Study

PURPOSE

To investigate the effects of resveratrol (Res) on human fetal scleral fibroblasts (HFSFs) and its potential mechanism.

METHODS

HFSFs were randomly divided into the Res-treated group and the control group. Following, HFSFs were treated with or without a concentration of 10 μM Res for 48 h. To detect the expression of related genes, reverse transcription quantitative PCR (RT-qPCR) and western blotting were used. The apoptosis rate of different groups was determined using flow cytometry.

RESULTS

The mRNA expression of matrix metalloproteinase 2 (MMP-2), Collagen, Type I, Alpha 1 (COL1A1), Janus Kinase 2 (JAK2), and Signal Transducer and Activator of Transcription 3 (STAT3)" was downregulated in the Res-treatment group compared to the control group, according to RT-qPCR. Western blotting revealed that Res therapy reduced the expression of MMP-2, JAK2, P-JAK2, STAT3, P-STAT3, and Bcl-2 associated protein X (Bax) while increasing the expression of COL1A1 and B-cell lymphoma-2 (Bcl-2). Flow cytometry showed that the cell apoptosis rate was significantly lower in HFSFs treated with Res.

CONCLUSIONS

In conclusion, these findings suggest that Res increases COL1A1 expression while inhibiting MMP-2 and cell apoptosis in HFSFs, possibly through modulation of the JAK2/STAT3 signaling pathway.

Therapeutic Effects of Anti-Inflammatory and Anti-Oxidant Nutritional Supplementation in Retinal Ischemic Diseases

Appropriate nutrients are essential for cellular function. Dietary components can alter the risk of systemic metabolic diseases, including cardiovascular diseases, cancer, diabetes, and obesity, and can also affect retinal diseases, including age-related macular degeneration, diabetic retinopathy, and glaucoma. Dietary nutrients have been assessed for the prevention or treatment of retinal ischemic diseases and the diseases of aging. In this article, we review clinical and experimental evidence concerning the potential of some nutritional supplements to prevent or treat retinal ischemic diseases and provide further insights into the therapeutic effects of nutritional supplementation on retinopathies. We will review the roles of nutrients in preventing or protecting against retinal ischemic diseases.

Boosting wound healing in diabetic rats: The role of nicotinamide riboside and resveratrol in UPR modulation and pyroptosis inhibition

BACKGROUND

Diabetes-related skin ulcers provide a substantial therapeutic issue, sometimes leading to amputation, needing immediate practical treatments for efficient wound care. While the exact mechanisms are unknown, pyroptosis and deregulation of the unfolded protein response (UPR) are known to exacerbate inflammation. Nicotinamide Riboside (NR) and Resveratrol (RV), which are known for their Nicotinamide adenine dinucleotide (NAD+) boosting and anti-inflammatory properties, are being studied as potential treatments. The purpose of this study was to shed light on the underlying molecular mechanisms and explore the medical application of NR and RV in diabetic wound healing.

METHODS

54 male Sprague-Dawley rats divided into control, diabetic (DM), Gel Base, DM-NR, DM-RV, and DM-NR + RV. Rats were orally administered 50 mg/kg/day of RV and 300 mg/kg/day of NR for 5 weeks. Following diabetes induction, their wounds were topically treated with 5 % NR and RV gel for 15 days. The wound closure rate, body weight, and serum lipid profiles were examined. Gene expression study evaluated UPR and pyroptosis-related genes (BIP, PERK, ATF6, IRE1α, sXBP1, CHOP, NLRP3, caspase-1, NFκB, and IL1-β) in wound tissues, alongside histological assessment of cellular changes.

RESULTS

NR and RV treatments greatly enhanced wound healing. Molecular investigation demonstrated UPR and pyroptosis marker modifications, suggesting UPR balance and anti-inflammatory effects. Histological investigation demonstrated decreased inflammation and increased re-epithelialization. The combination of NR and RV therapy had better results than either treatment alone.

CONCLUSION

This study shows that NR and RV have therapeutic promise in treating diabetic wounds by addressing UPR dysregulation, and pyroptosis. The combination therapy is a viable strategy to improving the healing process, providing a multimodal intervention for diabetic skin ulcers. These findings pave the way for additional investigation and possible therapeutic applications, giving hope for better outcomes in diabetic wound care.

SIRT1: a promising therapeutic target in type 2 diabetes mellitus

A significant increase in the worldwide incidence and prevalence of type 2 diabetic mellitus (T2DM) has elevated the need for studies on novel and effective therapeutic strategies. Sirtuin 1 (SIRT1) is an NAD + dependent protein deacetylase with a critical function in the regulation of glucose/lipid metabolism, insulin resistance, inflammation, oxidative stress, and mitochondrial function. SIRT1 is also involved in the regulation of insulin secretion from pancreatic β-cells and protecting these cells from inflammation and oxidative stress-mediated tissue damages. In this regard, major SIRT1 activators have been demonstrated to exert a beneficial impact in reversing T2DM-related complications including cardiomyopathy, nephropathy, retinopathy, and neuropathy, hence treating T2DM. Therefore, an accumulating number of recent studies have investigated the efficacy of targeting SIRT1 as a therapeutic strategy in T2DM. In this review we aimed to discuss the current understanding of the physiological and biological roles of SIRT1, then its implication in the pathogenesis of T2DM, and the therapeutic potential of SIRT1 in combating T2DM.

Molecular pathways of NF-ĸB and NLRP3 inflammasome as potential targets in the treatment of inflammation in diabetic wounds: A review

Diabetic wounds are slow healing wounds characterized by disordered healing processes and frequently take longer than three months to heal. One of the defining characteristics of impaired diabetic wound healing is an abnormal and unresolved inflammatory response, which is primarily brought on by abnormal macrophage innate immune signaling activation. The persistent inflammatory state in a diabetic wound may be attributed to inflammatory pathways such as nuclear factor kappa B (NF-ĸB) and nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which have long been associated with inflammatory diseases. Despite the available treatments for diabetic foot ulcers (DFUs) that include debridement, growth factor therapy, and topical anti-bacterial agents, successful wound healing is still hampered. Further understanding of the molecular mechanism of these pathways could be useful in designing potential therapeutic targets for diabetic wound healing. This review provides an update and novel insights into the roles of NF-ĸB and NLRP3 pathways in the molecular mechanism of diabetic wound inflammation and their potential as therapeutic targets in diabetic wound healing.

Resveratrol Alleviates Retinal Ischemia-Reperfusion Injury by Inhibiting the NLRP3/Gasdermin D/Caspase-1/Interleukin-1β Pyroptosis Pathway

Purpose

The purpose of this study is to investigate the anti-pyroptotic effect of resveratrol in the context of ischemia-reperfusion (I/R)-induced retinal injury, with a particular focus on Müller glial cells (MGCs) and to elucidate the underlying molecular mechanisms.

Methods

The retinal I/R model was constructed in mice and pyroptotic markers were measured at six, 12, 24, 48, and 72 hours after I/R injury to determine the peak of pyroptotic activity. The effects of resveratrol on pyroptosis, inflammasomes, and the activation of MGCs after I/R injury were observed on the retina of mice. Moreover, induction of pyroptosis in rat Müller glial cells (r-MC) via lipopolysaccharide was used to explore the effects of resveratrol on pyroptosis of r-MC in vitro.

Results

After the induction of retinal I/R injury in mice, the intricate involvement of pyroptosis in the progressive degeneration of the retina was observed, reaching its zenith at the onset of 24 hours after I/R injury. Resveratrol treatment alleviated I/R injury on the retina, relieved retinal ganglion cells death. In addition, resveratrol inhibited Caspase-1 activation, gasdermin D (GSDMD-N) cleavage, the inflammasome assembly, and the release of inflammatory cytokines, simultaneously relieving the MGCs activation. Furthermore, resveratrol inhibited the pyroptosis-related NLRP3/GSDMD-N/TMS1/ASC/Caspase-1/IL-1β pathway in r-MC cells, and mitigated cells death in vitro.

Conclusions

Pyroptosis plays an important role in the pathogenesis of retinal I/R injury. Resveratrol can attenuate pyroptotic-driven damage in the retina and MGC by inhibiting the NLRP3/GSDMD-N/TMS1/ASC/Caspase-1/IL-1β pyroptosis pathway.

SIRT1 Inhibits High Glucose-Induced TXNIP/NLRP3 Inflammasome Activation and Cataract Formation

Purpose

To determine whether SIRT1 regulates high glucose (HG)-induced inflammation and cataract formation through modulating TXNIP/NLRP3 inflammasome activation in human lens epithelial cells (HLECs) and rat lenses.

Methods

HG stress from 25 to 150 mM was imposed on HLECs, with treatments using small interfering RNAs (siRNAs) targeting NLRP3, TXNIP, and SIRT1, as well as a lentiviral vector (LV) for SIRT1. Rat lenses were cultivated with HG media, with or without the addition of NLRP3 inhibitor MCC950 or SIRT1 agonist SRT1720. High mannitol groups were applied as the osmotic controls. Real-time PCR, Western blots, and immunofluorescent staining evaluated the mRNA and protein levels of SIRT1, TXNIP, NLRP3, ASC, and IL-1β. Reactive oxygen species (ROS) generation, cell viability, and death were also assessed.

Results

HG stress induced a decline in SIRT1 expression and caused TXNIP/NLRP3 inflammasome activation in a concentration-dependent manner in HLECs, which was not observed in the high mannitol-treated groups. Knocking down NLRP3 or TXNIP inhibited NLRP3 inflammasome-induced IL-1β p17 secretion under HG stress. Transfections of si-SIRT1 and LV-SIRT1 exerted inverse effects on NLRP3 inflammasome activation, suggesting that SIRT1 acts as an upstream regulator of TXNIP/NLRP3 activity. HG stress induced lens opacity and cataract formation in cultivated rat lenses, which was prevented by MCC950 or SRT1720 treatment, with concomitant reductions in ROS production and TXNIP/NLRP3/IL-1β expression levels.

Conclusions

The TXNIP/NLRP3 inflammasome pathway promotes HG-induced inflammation and HLEC pyroptosis, which is negatively regulated by SIRT1. This suggests viable strategies for treating diabetic cataract.

Resveratrol: Its Path from Isolation to Therapeutic Action in Eye Diseases

Due to the confirmed therapeutic potential of resveratrol (Rv) for eye diseases, namely its powerful anti-angiogenic and antioxidant effects, this molecule must be studied more deeply. Nowadays, the pharmaceutic and pharmacokinetic available studies offer a troubling picture because of its low stability and bioavailability. To overcome this problem, researchers started to design and create different delivery systems that could improve the delivery amount of Rv. Therefore, this review aims to shed light on the proper and efficient techniques to isolate, purify and quantify the Rv molecule, and how this therapeutic molecule can be a part of a delivery system. The Rv great impact on aspects regarding its stability, bioavailability and absorption are also debated here, based on the existent literature on in vitro and in vivo human and animal studies. Moreover, after its absorption the Rv influence at the molecular level in ocular pathologies is described. In addition, the present review summarizes the available literature about Rv, hoping that Rv will gain more attention to investigate its unexplored side.

Effects of air pollution on myopia: an update on clinical evidence and biological mechanisms

Myopia is one of the most common forms of refractive eye disease and considered as a worldwide pandemic experienced by half of the global population by 2050. During the past several decades, myopia has become a leading cause of visual impairment, whereas several factors are believed to be associated with its occurrence and development. In terms of environmental factors, air pollution has gained more attention in recent years, as exposure to ambient air pollution seems to increase peripheral hyperopia defocus, affect the dopamine pathways, and cause retinal ischemia. In this review, we highlight epidemiological evidence and potential biological mechanisms that may link exposure to air pollutants to myopia. A thorough understanding of these mechanisms is a key for establishing and implementing targeting strategies. Regulatory efforts to control air pollution through effective policies and limit individual exposure to preventable risks are required in reducing this global public health burden.

Endothelial cell metabolic memory causes cardiovascular dysfunction in diabetes

AIMS

The aim of this study was to identify the molecular mechanism for hyperglycaemia-induced metabolic memory in endothelial cells (ECs), and to show its critical importance to development of cardiovascular dysfunction in diabetes.

METHODS AND RESULTS

Hyperglycaemia induces increased nuclear factor-κB (NF-κB) signalling, up-regulation of miR-27a-3p, down-regulation of nuclear factor erythroid-2 related factor 2 (NRF2) expression, increased transforming growth factor-β (TGF-β) signalling, down-regulation of miR-29, and induction of endothelial-to-mesenchymal transition (EndMT), all of which are memorized by ECs and not erased when switched to a low glucose condition, thereby causing perivascular fibrosis and cardiac dysfunction. Similar metabolic memory effects are found for production of nitric oxide (NO), generation of reactive oxygen species (ROS), and the mitochondrial oxygen consumption rate in two different types of ECs. The observed metabolic memory effects in ECs are blocked by NRF2 activator tert-butylhydroquinone and a miR-27a-3p inhibitor. In vivo, the NRF2 activator and miR-27a-3p inhibitor block cardiac perivascular fibrosis and restore cardiovascular function by decreasing NF-κB signalling, down-regulating miR-27a-3p, up-regulating NRF2 expression, reducing TGF-β signalling, and inhibiting EndMT during insulin treatment of diabetes in streptozotocin-induced diabetic mice, whereas insulin alone does not improve cardiac function.

CONCLUSIONS

Our data indicate that disruption of hyperglycaemia-induced EC metabolic memory is required for restoring cardiac function during treatment of diabetes, and identify a novel molecular signalling pathway of NF-κB/miR-27a-3p/NRF2/ROS/TGF-β/EndMT involved in metabolic memory.

Gliquidone improves retinal injury to relieve diabetic retinopathy via regulation of SIRT1/Notch1 pathway

Background

Diabetic retinopathy (DR) is a common and potentially devastating microvascular complication of diabetes mellitus (DM). The main features of DR are inflammation and oxidative damage. Gliquidone (GLI) is confirmed to be a hypoglycemic drug by oral administration. The current study is aimed to investigate the role and mechanism of GLI on the pathogenesis of DR.

Methods

High glucose (HG)-induced human retinal endothelial cells (HRECs) were used to explore the anti-inflammatory and anti-oxidant effects of GLI on DR in vitro. Streptozotocin (STZ)-induced DM rats were used to investigate the effects of GLI on retinal structures, inflammation, and oxidative stress. The levels of SIRT1/Notch1 pathway-related proteins were determined by western blotting.

Results

GLI treatment promoted the viability and inhibited the apoptosis of HG-induced HRECs. Meanwhile, the levels of interleukin (IL)-6, IL-1β, tumour necrosis factor alpha and reactive oxygen species were suppressed, while both catalase and superoxide dismutase were elevated after GLI treatment in HG-induced HRECs. Furthermore, we found that Silencing information regulator 2 related enzyme 1 (SIRT1) silencing reversed the inhibiting effects of GLI on the levels of protein Notch1 and effector genes Hes1 and Hey2. Similar anti-inflammatory and anti-oxidant effects of GLI in STZ-induced DM rats were observed. Additionally, GLI administration also repressed vascular hyperpermeability in vivo.

Conclusion

GLI may be an effective agent to improve DR through repression of inflammation and oxidative stress via SIRT1/Notch1 pathway.

Resveratrol Inhibits NLRP3 Inflammasome-Induced Pyroptosis and miR-155 Expression in Microglia Through Sirt1/AMPK Pathway

Resveratrol is a natural polyphenolic compound with a wide range of biological activities such as antioxidant, anti-carcinogenic, anti-obesity, anti-aging, anti-inflammatory, immunomodulatory properties. Accumulating evidence suggests that resveratrol has pharmacological benefits in life-threatening diseases, including cardiovascular disease, cancer, diabetes, and neurodegenerative diseases. Resveratrol is widely known for its anti-inflammatory properties; however, signaling mechanisms of anti-inflammatory action are still elusive. Studies have illustrated that resveratrol can control different regulatory pathways by altering the expression and consequently regulatory effects of microRNAs. Our study aims to clarify the regulatory mechanisms of resveratrol in its anti-inflammatory features in the N9 microglial cell line. Our results demonstrated that resveratrol inhibits LPS- and ATP-activated NLRP3 inflammasome and protects microglial cells upon oxidative stress, proinflammatory cytokine production, and pyroptotic cell death resulting from inflammasome activation. Additionally, resveratrol inhibits nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling and activates AMPK/Sirt1 pathways. Furthermore, our results indicated that resveratrol downregulated inflammasome-induced miR-155 expression. Then, inhibition of AMPK and Sirt1 pathways has significantly reversed protective effect of resveratrol on miR-155 expression. To sum up, our results suggest that resveratrol suppresses the NLRP3 inflammasome and miR-155 expression through AMPK and Sirt1 pathways in microglia.

Efficacy and safety of vitamin supplements with resveratrol in diabetic macular edema: Long-term results of a comparative study

PURPOSE

To investigate the adjunct efficacy and safety of vitamin supplements, including resveratrol, in patients with diabetic macular edema (DME) treated with intravitreal anti-vascular endothelial factor (anti-VEGF) agents.

METHODS

Participants in this prospective study were 45 patients with DME, who were treated with either intravitreal anti-VEGF injections (n = 23, Group I) or with combination of intravitreal anti-VEGF injections and vitamin supplements, including resveratrol (n = 22, Group II). All patients underwent visual acuity measurement, slit-lamp examination and spectral domain-optical coherence tomography (SD-OCT) at baseline and monthly after the loading phase of three-monthly anti-VEGF injections, following a PRN protocol.

RESULTS

There was a statistically significant improvement in visual acuity in both groups at month 12 compared to baseline, although the mean change in visual acuity did not differ between the two groups (p = 0.183). Accordingly, there was a statistically significant decrease in central retinal thickness in both groups at month 12 compared to baseline, while the mean difference in central retinal thickness was significantly greater in the "combination" group. The mean number of intravitreal anti-VEGF injection was less in Group II (6.45 ± 1.12 in Group II vs. 7.39 ± 1.31 in Group I, p = 0.018).

CONCLUSIONS

Vitamin supplements with resveratrol was found to be an effective adjunct to intravitreal anti-VEGF injections in patients with DME, offering better anatomic restoration with less injections at the 12-month follow-up.

Ocular lamellar crystalline gels for sustained release and enhanced permeation of resveratrol against corneal neovascularization

Corneal neovascularization (CNV) is the major cause of blindness after eye injury; however, only several drugs can be applied and the invasive administration ways (i.e., intravitreal injection and subconjunctival injection) are used. Resveratrol is a highly effective anti-VEGF agent against CNV. However, its applications are limited due to its strong hydrophobicity and instability. Here, we developed a resveratrol-loaded ocular lamellar crystalline gel (ROLG) for high inhibition of CNV. ROLGs were composed of resveratrol, glyceryl monooleate (GMO), ethanol, and water, and their lamellar crystalline structures were identified by polarizing light microscopy and small-angle X-ray scattering. High drug loading (4.4 mg/g) of ROLGs was achieved due to the hydrogen bonding between GMO and resveratrol. Resveratrol showed sustained release with 67% accumulative release in 7 h, which was attributed to the slow erosion of gels. Resveratrol in ROLGs had a high corneal permeation 3 times higher than resveratrol in hyaluronic acid suspensions (RHSs). ROLGs were administered to rats only once a day because of their strong retention on the cornea surface. ROLGs were safe due to the very little contact of ethanol in ROLGs to the cornea. CNV post-rat corneal alkaline injury was highly inhibited by ROLGs, resulting from the attenuation of corneal VEGF expression and then corneal healing was improved. The ROLG was a promising ocular medicine for the prevention of CNV.

Resveratrol Can Attenuate Astrocyte Activation to Treat Spinal Cord Injury by Inhibiting Inflammatory Responses

Several preclinical and clinical studies have attempted to elucidate the pathophysiological mechanism associated with spinal cord injury. However, investigations have been unable to define the precise related mechanisms, and this has led to the lack of effective therapeutic agents for the condition. Neuroinflammation is one of the predominant processes that hinder spinal cord injury recovery. Resveratrol is a compound that has several biological features, such as antioxidation, antibacterial, and antiinflammation. Herein, we reviewed preclinical and clinical studies to delineate the role of toll-like receptors, nod-like receptors, and astrocytes in neuroinflammation. In particular, the alteration of astrocytes in SCI causes glial scar formation that impedes spinal cord injury recovery. Therefore, to improve injury recovery would be to prevent the occurrence of this process. Resveratrol is safe and effective in the significant modulation of neuroinflammatory factors, particularly those mediated by astrocytes. Thus, its potential ability to enhance the injury recovery process and ameliorate spinal cord injury.

Resveratrol Alleviates the Inhibitory Effect of Tunicamycin-Induced Endoplasmic Reticulum Stress on Expression of Genes Involved in Thyroid Hormone Synthesis in FRTL-5 Thyrocytes

Recently, ER stress induced by tunicamycin (TM) was reported to inhibit the expression of key genes involved in thyroid hormone synthesis, such as sodium/iodide symporter (NIS), thyroid peroxidase (TPO) and thyroglobulin (TG), and their regulators such as thyrotropin receptor (TSHR), thyroid transcription factor-1 (TTF-1), thyroid transcription factor-2 (TTF-2) and paired box gene 8 (PAX-8), in FRTL-5 thyrocytes. The present study tested the hypothesis that resveratrol (RSV) alleviates this effect of TM in FRTL-5 cells. While treatment of FRTL-5 cells with TM alone (0.1 µg/mL) for 48 h strongly induced the ER stress-sensitive genes heat shock protein family A member 5 (HSPA5) and DNA damage inducible transcript 3 (DDIT3) and repressed NIS, TPO, TG, TSHR, TTF-1, TTF-2 and PAX-8, combined treatment with TM (0.1 µg/mL) and RSV (10 µM) for 48 h attenuated this effect of TM. In conclusion, RSV alleviates TM-induced ER stress and attenuates the strong impairment of expression of genes involved in thyroid hormone synthesis and their regulators in FRTL-5 thyrocytes exposed to TM-induced ER stress. Thus, RSV may be useful for the treatment of specific thyroid disorders, provided that strategies with improved oral bioavailability of RSV are applied.

Resveratrol Prevents GLUT3 Up-Regulation Induced by Middle Cerebral Artery Occlusion

Glucose transporter (GLUT)3 up-regulation is an adaptive response activated to prevent cellular damage when brain metabolic energy is reduced. Resveratrol is a natural polyphenol with anti-oxidant and anti-inflammatory features that protects neurons against damage induced in cerebral ischemia. Since transcription factors sensitive to oxidative stress and inflammation modulate GLUT3 expression, the purpose of this work was to assess the effect of resveratrol on GLUT3 expression levels after ischemia. Male Wistar rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by different times of reperfusion. Resveratrol (1.9 mg/kg; i. p.) was administered at the onset of the restoration of the blood flow. Quantitative-PCR and Western blot showed that MCAO provoked a substantial increase in GLUT3 expression in the ipsilateral side to the lesion of the cerebral cortex. Immunofluorescence assays indicated that GLUT3 levels were upregulated in astrocytes. Additionally, an important increase in GLUT3 occurred in other cellular types (e.g., damaged neurons, microglia, or infiltrated macrophages). Immunodetection of the microtubule-associated protein 2 (MAP2) showed that MCAO induced severe damage to the neuronal population. However, the administration of resveratrol at the time of reperfusion resulted in injury reduction. Resveratrol also prevented the MCAO-induced increase of GLUT3 expression. In conclusion, resveratrol protects neurons from damage induced by ischemia and prevents GLUT3 upregulation in the damaged brain that might depend on AMPK activation.

Inhibitory effects of phytochemicals on NLRP3 inflammasome activation: A review

BACKGROUND

The NLRP3 inflammasome formation and following cytokine secretion is a crucial step in innate immune responses. Internal and external factors may trigger inflammasome activation and result in inflammatory cytokine secretion. Inflammasome formation and activity play critical roles in several disease pathologies such as cardiovascular, metabolic, renal, digestive, and CNS diseases. Underlying pathways are not yet clear, but phytochemicals as alternative therapies have been extensively used for suppression of inflammatory responses.

PURPOSE

In this review, we aimed to summarize in vivo and in vitro effects on NLRP3 inflammasome activation of selected phytochemicals.

METHOD

Three phytochemicals; Sulforaphane, Curcumin, and Resveratrol were selected, and studies were reviewed to clarify their intracellular signaling mechanism in NLRP3 inflammasome activity. PubMed and Scopus databases are used for the search. For sulforaphane, 8 articles, for curcumin, 25 articles, and for resveratrol, 41 articles were included in the review.

CONCLUSION

In vitro and in vivo studies pointed out that the selected phytochemicals have inhibitory properties on NLRP3 inflammasome activity. However, neither the mechanism is clear, nor the study designs and doses are standardized.

A Biochemometric Approach for the Identification of In Vitro Anti-Inflammatory Constituents in Masterwort

Peucedanum ostruthium (L.) Koch, commonly known as masterwort, has a longstanding history as herbal remedy in the Alpine region of Austria, where the roots and rhizomes are traditionally used to treat disorders of the gastrointestinal and respiratory tract. Based on a significant NF-κB inhibitory activity of a P. ostruthium extract (PO-E), this study aimed to decipher those constituents contributing to the observed activity using a recently developed biochemometric approach named ELINA (Eliciting Nature’s Activities). This -omics tool relies on a deconvolution of the multicomponent mixture, which was employed by generating microfractions with quantitative variances of constituents over several consecutive fractions. Using an optimized and single high-performance counter-current chromatographic (HPCCC) fractionation step 31 microfractions of PO-E were obtained. ¹H NMR data and bioactivity data from three in vitro cell-based assays, i.e., an NF-ĸB reporter-gene assay and two NF-κB target-gene assays (addressing the endothelial adhesion molecules E-selectin and VCAM-1) were collected for all microfractions. Applying heterocovariance analyses (HetCA) and statistical total correlation spectroscopy (STOCSY), quantitative variances of ¹H NMR signals of neighboring fractions and their bioactivities were correlated. This revealed distinct chemical features crucial for the observed activities. Complemented by LC-MS-CAD data this biochemometric approach differentiated between active and inactive constituents of the complex mixture, which was confirmed by NF-κB reporter-gene testing of the isolates. In this way, four furanocoumarins (imperatorin, ostruthol, saxalin, and 2’-O-acetyloxypeucedanin), one coumarin (ostruthin), and one chromone (peucenin) were identified as NF-κB inhibiting constituents of PO-E contributing to the observed NF-ĸB inhibitory activity. Additionally, this approach also enabled the disclose of synergistic effects of the PO-E metabolites imperatorin and peucenin. In sum, prior to any isolation an early identification of even minor active constituents, e.g. peucenin and saxalin, ELINA enables the targeted isolation of bioactive constituents and, thus, to effectively accelerate the NP-based drug discovery process.

Berberine Administration in Treatment of Colitis: A Review

Berberine (Brb) is one of the well-known naturally occurring compounds exclusively found in Berberis vulgaris and other members of this family, such as Berberis aristata, Berberis aroatica, and Berberis aquifolium. This plant-derived natural compound has a variety of therapeutic impacts, including anti-oxidant, anti-inflammatory, anti-diabetic, and anti-tumor. Multiple studies have demonstrated that Brb has great anti-inflammatory activity and is capable of reducing the levels of proinflammatory cytokines, while it enhances the concentrations of anti-inflammatory cytokines, making it suitable for the treatment of inflammatory disorders. Colitis is an inflammatory bowel disease with chronic nature. Several factors are involved in the development of colitis and it appears that inflammation and oxidative stress are the most important ones. With respect to the anti-inflammatory and antioxidant effects of Brb, its administration seems to be beneficial in the treatment of colitis. In the present review, the protective effects of Brb in colitis treatment and its impact on molecular pathways are discussed.