Isoorientin Inhibits Inflammation in Macrophages and Endotoxemia Mice by Regulating Glycogen Synthase Kinase 3β

Inducing ferroptosis by traditional medicines: a novel approach to reverse chemoresistance in lung cancer

Lung cancer is the leading cause of global cancer-related deaths. Platinum-based chemotherapy is the first-line treatment for the most common type of lung cancer, i.e., non-small-cell lung cancer (NSCLC), but its therapeutic efficiency is limited by chemotherapeutic resistance. Therefore, it is vital to develop effective therapeutic modalities that bypass the common molecular mechanisms associated with chemotherapeutic resistance. Ferroptosis is a form of non-apoptotic regulated cell death characterized by iron-dependent lipid peroxidation (LPO). Ferroptosis is crucial for the proper therapeutic efficacy of lung cancer-associated chemotherapies. If targeted as a novel therapeutic mechanism, ferroptosis modulators present new opportunities for increasing the therapeutic efficacy of lung cancer chemotherapy. Emerging studies have revealed that the pharmacological induction of ferroptosis using natural compounds boosts the efficacy of chemotherapy in lung cancer or drug-resistant cancer. In this review, we first discuss chemotherapeutic resistance (or chemoresistance) in lung cancer and introduce the core mechanisms behind ferroptosis. Then, we comprehensively summarize the small-molecule compounds sourced from traditional medicines that may boost the anti-tumor activity of current chemotherapeutic agents and overcome chemotherapeutic resistance in NSCLC. Cumulatively, we suggest that traditional medicines with ferroptosis-related anticancer activity could serve as a starting point to overcome chemotherapeutic resistance in NSCLC by inducing ferroptosis, highlighting new potential therapeutic regimens used to overcome chemoresistance in NSCLC.

Exploring the efficacy of ethnomedicinal plants of Himalayan region against the malaria parasite

ETHNOPHARMACOLOGICAL RELEVANCE

Plasmodium falciparum multi-drug resistant (MDR) strains are a great challenge to global health care. This predicament implies the urgent need to discover novel antimalarial drugs candidate from alternative natural sources. The Himalaya constitute a rich repository of medicinal plants which have been used traditionally in the folklore medicine since ages and having no scientific evidence for their activity. Crambe kotschyana Boiss. and Eremurus himalaicus Baker are used for their antipyretic and hepatoprotective properties in Kinnaur district of Himachal Pradesh, India.

AIM OF THE STUDY

This study would investigate the antiplasmodial efficacy of C. kotschyana and E. himalaicus extracts, their fractions and active components using in vitro, in vivo and in silico approaches to provide a scientific insight into their activity.

METHODS

The methanol extracts of C. kotschyana (CKME) and E. himalaicus (EHME) were prepared by maceration followed by fractionation using ethyl acetate. The isolation of flavonoid glycosides isorhamnetin-3, 7-di-O-glucoside from C. kotschyana and luteolin-6-C-glucoside (isoorientin) from E. himalaicus was carried out by antiplasmodial activity-guided isolation. In vitro antimalarial activity was assessed by WHO method while in vitro cytotoxicity was ascertained employing the MTT assay. Molecular docking and molecular dynamics simulation were performed using the Glide module of Schrödinger Software and Gromacs-2022 software package respectively. In vivo curative activity was assessed by Ryley and Peters method.

RESULTS

The methanol extracts of both the plants illustrated the best antiplasmodial activity followed by the ethyl acetate fractions. Iso-orientin (IC50 6.49 μg/ml) and Isorhamnetin-3,7-di-O-glucoside (IC50 9.22 μg/ml) illustrated considerable in vitro activity even against P. falciparum resistant strain. Extracts/fractions as well as the isolated compounds were found to be non-toxic with CC50 > 640 μg/ml. Molecular docking studies were performed with these 2 O-glucosides against four malaria targets to understand the binding pose of these molecules and the results suggested that these molecules have selectivity for lactate dehydrogenase enzyme. CKME and EHME exhibited curative activity in vivo along with increase in Mean Survival Time of mice.

CONCLUSION

The research delineated the scientific evidence that both the therapeutic herbs possessed antimalarial activity and notably, bioactive compounds responsible to exhibit the antimalarial activity have been isolated, identified and characterized. Further studies are underway to assess the antiplasmodial efficacy of isolated compounds alone and in combination with standard antimalarials.

Astragalus polysaccharide improves diabetic ulcers by promoting M2-polarization of macrophages to reduce excessive inflammation via the β-catenin/ NF-κB axis at the late phase of wound-healing

Ethnopharmacological relevance

Astragalus polysaccharide (APS), the most biologically active ingredient of Astragali Radix, is used to treat diabetes mellitus (DM)-related chronic wounds in traditional Chinese medicine for several decades. This herb possesses an anti-inflammatory effect. Our study proved that APS can reduce excessive inflammation at the late phase of wound-healing in diabetic ulcers.

Aim of the study

To clarify the molecular mechanism of APS in promoting wound-healing via reducing excessive inflammation in diabetic ulcers during the late stages of wound-healing.

Methods and materials

The rat model of the diabetic ulcers was established via intraperitoneal injection of streptozocin (60 mg/kg). We detected the regulation of APS on diabetic ulcers by measuring wound-healing rates. Bioinformatics was used to predict the target genes of APS, and autodocking was used to predict the combination of APS and target genes. Immunohistochemistry, Enzyme-linked immunosorbent assay, Western blot, immunofluorescence staining, flow cytometry, and flow cytometric sorting were investigated.

Results

The results demonstrated that APS promoted wound-healing and inhibited excessive inflammation at the late phase of wound-healing in diabetic rats. Mechanistic findings showed that APS promoted the expression of β-catenin and Rspo3 while inhibiting the expression of NF-KB and GSK-3β, which leads to the transformation of M1-type macrophages into M2-type macrophages and thus reducing excessive inflammation at the late phase of wound-healing in diabetic ulcers.

Conclusion

We found an interesting finding that APS promoted the polarization of macrophages towards M2-type through the β-catenin/NF-κB axis to reduce excessive inflammation at the late phase of wound-healing. Therefore, APS may be a promising drug for treating diabetic ulcers in clinic.

Isoorientin reverses lung cancer drug resistance by promoting ferroptosis via the SIRT6/Nrf2/GPX4 signaling pathway

Cisplatin, or DDP, is a highly successful and well-known chemotherapy drug used to treat cancer. Acquired resistance to chemotherapy is a major clinical concern, yet the mechanisms of this resistance are still unknown. Ferroptosis is a type of cell death distinct from other forms, fueled by a buildup of iron-associated lipid reactive oxygen species (ROS). Gaining insight into the process of ferroptosis could lead to novel treatments for overcoming cancer resistance. In this study, the combination of isoorientin (IO) and DDP treatment resulted in a significant decrease in the viability of drug-resistant cells, a substantial increase in intracellular iron, malondialdehyde (MDA) and ROS concentrations, a notable decrease in glutathione concentration, and the occurrence of ferroptosis in cells, as revealed by in vitro and in vivo experiments. Additionally, there was a decrease in the expression of nuclear factor-erythroid factor 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and sirtuin 6 (SIRT6) proteins, and an increase in cellular ferroptosis. Isoorientin acts as a mediator to regulate cellular ferroptosis and reverse drug resistance in lung cancer cells by controlling the SIRT6/Nrf2/GPX4 signaling pathway. The findings of this study suggest that IO can promote ferroptosis and reverse drug resistance in lung cancer through the SIRT6/Nrf2/GPX4 signaling pathway, thus offering a theoretical basis for its potential clinical application.

[Akt2 inhibitor promotes M2 macrophage polarization in rats with periapical inflammation by reducing miR-155-5p expression]

OBJECTIVE

To investigate the effect of Akt2 inhibitor on macrophage polarization in the periapical tissue in a rat model of periapical inflammation.

METHODS

Rat models of periapical inflammation were established in 28 normal SD rats by opening the pulp cavity of the mandibular first molars, followed by injection of normal saline and Akt2 inhibitor into the left and right medullary cavities, respectively. Four rats without any treatment served as the healthy control group. At 7, 14, 21 and 28 days after modeling, 7 rat models and 1 control rat were randomly selected for observation of inflammatory infiltration in the periapical tissues by X-ray and HE staining. Immunohistochemistry was used to detect the expression and localization of Akt2, macrophages and the inflammatory mediators. RT-PCR was performed to detect the mRNA expressions of Akt2, CD86, CD163, inflammatory mediators, miR-155-5p and C/EBPβ to analyze the changes in macrophage polarization.

RESULTS

X-ray and HE staining showed that periapical inflammation was the most obvious at 21 days after modeling in the rats. Immunohistochemistry and RT-PCR showed that compared with those in the control rats, the expressions of Akt2, CD86, CD163, miR-155-5p, C/EBPβ, and IL-10 increased significantly in the rat models at 21 days (P < 0.05). Compared with saline treatment, treatment with the Akt2 inhibitor significantly decreased the expression levels of Akt2, CD86, miR-155-5p and IL-6 and the ratio of CD86+M1/CD163+M2 macrophages (P < 0.05) and increased the expression levels of CD163, C/EBPβ and IL-10 in the rat models (P < 0.05).

CONCLUSION

Inhibition of Akt2 can delay the progression of periapical inflammation in rats and promote M2 macrophage polarization in the periapical inflammatory microenvironment possibly by reducing miR-155-5p expression and activating the expression of C/EBPβ in the Akt signaling pathway.

Acai Berry (Euterpe sp.) Extracts Are Neuroprotective against L-Glutamate-Induced Toxicity by Limiting Mitochondrial Dysfunction and Cellular Redox Stress

Aberrant accumulation of the neurotransmitter L-glutamate (L-Glu) has been implicated as a mechanism of neurodegeneration, and the release of L-Glu after stroke onset leads to a toxicity cascade that results in neuronal death. The acai berry (Euterpe oleracea) is a potential dietary nutraceutical. The aim of this research was to investigate the neuroprotective effects of acai berry aqueous and ethanolic extracts to reduce the neurotoxicity to neuronal cells triggered by L-Glu application. L-Glu and acai berry effects on cell viability were quantified using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, and effects on cellular bioenergetics were assessed via quantitation of the levels of cellular ATP, mitochondrial membrane potential (MMP), and production of reactive oxygen species (ROS) in neuroblastoma cells. Cell viability was also evaluated in human cortical neuronal progenitor cell culture after L-Glu or/and acai berry application. In isolated cells, activated currents using patch-clamping were employed to determine whether L-Glu neurotoxicity was mediated by ionotropic L-Glu-receptors (iGluRs). L-Glu caused a significant reduction in cell viability, ATP, and MMP levels and increased ROS production. The co-application of both acai berry extracts with L-Glu provided neuroprotection against L-Glu with sustained cell viability, decreased LDH production, restored ATP and MMP levels, and reduced ROS levels. Whole-cell patch-clamp recordings showed that L-Glu toxicity is not mediated by the activation of iGluRs in neuroblastoma cells. Fractionation and analysis of acai berry extracts with liquid chromatography-mass spectrometry identified several phytochemical antioxidants that may have provided neuroprotective effects. In summary, the acai berry contains nutraceuticals with antioxidant activity that may be a beneficial dietary component to limit pathological deficits triggered by excessive L-Glu accumulations.

Isoorientin ameliorates OVA-induced asthma in a murine model of asthma

Allergic asthma which is induced by ovalbumin (OVA) is a chronic airway inflammation disease. Isoorientin (Iso) is a natural C-glucosyl flavone with many biological properties. We aimed to evaluate the effectiveness of Iso on OVA-induced allergic asthma. A total of 30 C57BL/6 mice were randomly divided into five groups: control group, OVA group, Dex (dexamethasone, 10 mg/kg) group, low-dose Iso group (Iso-L, 25 mg/kg), and high-dose Iso group (Iso-H, 50 mg/kg). The serum and bronchoalveolar lavage fluid (BALF) were collected for biochemical parameters, the lung tissue was collected for hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC), and western blot. The levels of IL-4, IL-5, IL-13, malondialdehyde (MDA), NO, and reactive oxygen species (ROS) in Iso-L and Iso-H groups were significantly lower than that in model group (p < 0.05). Simultaneously, the levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity were higher than that in model group (p < 0.05). Iso significantly ameliorated airway hyperresponsiveness. Meanwhile, H&E staining revealed that mice treated with Iso resulted in the ameliorated inflammatory cell infiltration and a reduction in interstitial thickening. The nuclear factor erythroid 2-like 2 (Nrf2) and HO-1 protein expression in Iso-L and Iso-H groups were enhanced over that in model group, while p-NF-κB-p65 and p-IκB-α protein expression was decreased (p < 0.05). Our research indicated that Iso alleviated the OVA-induced allergic asthma, and this effect can be explained by the modulation of Nrf2/HO-1 and NF-κB signaling pathway; thus, the results providing a therapeutic rationale for the treatment of Iso on allergic asthma.

Anti-Inflammatory Effects of Phytochemical Components of Clinacanthus nutans

Recent studies on the ethnomedicinal use of Clinacanthus nutans suggest promising anti-inflammatory, anti-tumorigenic, and antiviral properties for this plant. Extraction of the leaves with polar and nonpolar solvents has yielded many C-glycosyl flavones, including schaftoside, isoorientin, orientin, isovitexin, and vitexin. Aside from studies with different extracts, there is increasing interest to understand the properties of these components, especially regarding their ability to exert anti-inflammatory effects on cells and tissues. A major focus for this review is to obtain information on the effects of C. nutans extracts and its phytochemical components on inflammatory signaling pathways in the peripheral and central nervous system. Particular emphasis is placed on their role to target the Toll-like receptor 4 (TLR4)-NF-kB pathway and pro-inflammatory cytokines, the antioxidant defense pathway involving nuclear factor erythroid-2-related factor 2 (NRF2) and heme oxygenase 1 (HO-1); and the phospholipase A₂ (PLA₂) pathway linking to cyclooxygenase-2 (COX-2) and production of eicosanoids. The ability to provide a better understanding of the molecular targets and mechanism of action of C. nutans extracts and their phytochemical components should encourage future studies to develop new therapeutic strategies for better use of this herb to combat inflammatory diseases.

Exosomes: Potential Player in Endothelial Dysfunction in Cardiovascular Disease

Exosomes are spherical bilayer membrane vesicles with an average diameter of 40-100 nm. These particles perform a wide range of biological activities due to their contents, including proteins, nucleic acids, lipids, lncRNA, and miRNA. Exosomes are involved in inflammation induction, oxidative stress and apoptosis, which can be effective in endothelial dysfunction. Due to the induction of mentioned processes in the endothelial cells, the intercellular connections are destroyed, cell permeability increases and finally cell efficiency decreases and functional defects occur. Cardiovascular disease (CVDs) are of consequences of endothelial dysfunction. Thus by identifying the exosome signaling pathways, which induce inflammation, oxidative stress, and apoptosis, endothelial dysfunction and subsequently CVDs can be reduced; exosomes can be used for appropriate target therapy.

Protective Effect of Isoorientin on Oleic Acid-Induced Oxidative Damage and Steatosis in Rat Liver Cells

The harm of nonalcoholic fatty liver disease to human health is increasing, which calls for urgent prevention and treatment of the disease. Isoorientin is an effective ingredient of Chinese herbal medicine with anti-inflammatory and antioxidant effects. However, the effect of isoorientin in nonalcoholic fatty liver disease is still unclear. In this study, combined in vivo and in vitro experiments, through pathological observation, flow cytometry, immunofluorescence and western blot analysis to explore the role of isoorientin in steatosis and reveal its molecular mechanism. The results demonstrated that oleic acid treatment significantly increased the content of ROS and lipid droplets in rat hepatocytes, and promoted the expression of γH2AX, HO-1, PPARγ, SREBP-1c, FAS. The ROS content in the cells of co-treated with isoorientin and oleic acid was significantly reduced compared to the oleic acid group, and the expression of γH2AX, HO-1, PPARγ, SREBP-1c, FAS, and the nuclear translocation of NF-κB p65 were also significantly inhibited. Our data showed that oleic acid induce oxidative damage and steatosis in hepatocytes both in vitro and in vivo, and activate the PPARγ/NF-κB p65 signal pathway. Moreover, isoorientin can significantly reduce oleic acid -induced oxidative damage and steatosis by regulating the PPARγ/NF-kB p65 signal pathway.

Isoorientin Affects Markers of Alzheimer's Disease via Effects on the Oral and Gut Microbiota in APP/PS1 Mice

BACKGROUND

There is growing evidence of strong associations between the pathogenesis of Alzheimer's disease (AD) and dysbiotic oral and gut microbiota. Recent studies demonstrated that isoorientin (ISO) is anti-inflammatory and alleviates markers of AD, which were hypothesized to be mediated by the oral and gut microbiota.

OBJECTIVES

We studied the effects of oral administration of ISO on AD-related markers and the oral and gut microbiota in mice.

METHODS

Eight-month-old amyloid precursor protein/presenilin-1 (AP) transgenic male mice were randomly allocated to 3 groups of 15 mice each: vehicle (AP) alone or with a low dose of ISO (AP + ISO-L; 25 mg/kg) or a high dose of ISO (AP + ISO-H; 50 mg/kg). Age-matched wild-type (WT) C57BL/6 male littermates were used as controls. The 4 groups were treated intragastrically with ISO or sterilized ultrapure water for 2 months. AD-related markers in the brain, serum, colon, and liver were analyzed with immunohistochemical and histochemical staining, Western blotting, and ELISA. Oral and gut microbiotas were analyzed using 16S ribosomal RNA gene sequencing.

RESULTS

The high-dose ISO treatment significantly decreased amyloid beta 42-positive deposition by 38.1% and 45.2% in the cortex and hippocampus, respectively, of AP mice (P < 0.05). Compared with the AP group, both ISO treatments reduced brain phospho-Tau, phosphor-p65, phosphor-inhibitor of NF-κB, and brain and serum LPS and TNF-α by 17.9%-72.5% and increased brain and serum IL-4 and IL-10 by 130%-210% in the AP + ISO-L and AP + ISO-H groups (P < 0.05). Abundances of 26, 25, and 23 microbial taxa in oral, fecal and cecal samples, respectively, were increased in both the AP + ISO-L and AP + ISO-H groups relative to the AP group [linear discriminant analysis (LDA) >3.0; P < 0.05]. Gram-negative bacteria, Alteromonas, Campylobacterales, and uncultured Bacteroidales bacterium were positively correlated (rho = 0.28-0.59; P < 0.05) with the LPS levels and responses of inflammatory cytokines.

CONCLUSIONS

The microbiota-gut-brain axis is a potential mechanism by which ISO reduces AD-related markers in AP mice.

Anti-Neuroinflammatory Effects of a Semi-Synthetic Isoorientin-Based Glycogen Synthase Kinase-3β Inhibitor in Lipopolysaccharide-Activated Microglial Cells

Neuroinflammation contributes to the pathogenesis of several neurodegenerative disorders. Glycogen synthase kinase-3β (GSK-3β) regulates the release of proinflammatory cytokines and promotes inflammatory responses in immune cells. Microglia are the resident mononuclear immune cells of the central nervous system. Here, we investigated the anti-neuroinflammatory effects of (2S,3S,4R,5R,6S)-6-(2-(3,4-dimethoxyphenyl)-5,7-dimethoxy-4-oxo-4H-chromen-6-yl)-3,4,5-trihydroxy-N-((S)-1,1,1-trifluoropropan-2-yl)tetrahydro-2H-pyran-2-carboxamide (TFGF-18), a semisynthetic GSK-3β inhibitor, in lipopolysaccharide (LPS) activation of spontaneously immortalized SIM-A9 microglial cells and of mouse cortical microglia. TFGF-18 at 2.5 μM concentration inhibited LPS-induced production of nitric oxide by 56.3% and the proinflammatory cytokines TNF-α and IL-1β by 28.3 and 59.2% in SIM-A9 cells, respectively, relative to the LPS treatment control group. Pretreatment of mouse primary microglial cells with TFGF-18 at 2.5 μM concentration led to a reduction of 58.7% in TNF-α+ microglial cells at 24 h post-LPS stimulation. The migration of LPS-activated SIM-A9 cells was also reduced by 26.7% with pretreatment of TFGF-18 in a scratch assay. Analyses of signaling pathways demonstrated that TFGF-18 led to the suppression of LPS-induced GSK-3β activation and p65/NF-κB activity. Furthermore, the co-culture of SIM-A9 with SH-SY5Y neuroblastoma cells showed the suppression of TFGF-18 to microglia-mediated neurotoxicity in vitro. The findings indicate strong inhibitory effects of TFGF-18 on LPS-induced microglia activation via regulation of GSK-3β and downstream p65/NF-κB signaling. The results suggest a potential role of TFGF-18 in neuroprotection via its anti-neuroinflammatory effect.

Fisetin mitigates hepatic ischemia-reperfusion injury by regulating GSK3β/AMPK/NLRP3 inflammasome pathway

BACKGROUND

Hepatic ischemia-reperfusion (I/R) injury (IRI) represents a crucial challenge in liver transplantation. Fisetin has anti-inflammatory, anti-aging and anti-oxidative properties. This study aimed to examine whether fisetin mitigates hepatic IRI and examine its underlying mechanisms.

METHODS

Sham or warm hepatic I/R operated mice were pretreated with fisetin (5, 10 or 20 mg/kg). Hepatic histological assessments, TUNEL assays and serum aminotransferase measurements were performed. An in vitro hypoxia/reoxygenation (H/R) model using RAW264.7 macrophages pretreated with fisetin (2.5, 5 or 10 µmol/L) was also used. Serum and cell supernatant concentrations of interleukin-1β (IL-1β), IL-18 and tumor necrosis factor-α (TNF-α) were determined by enzyme-linked immunosorbent assay (ELISA). Protein levels of p-GSK3β, p-AMPK and NLR family pyrin domain-containing 3 (NLRP3)-associated proteins were detected by Western blotting.

RESULTS

Compared with the I/R group, fisetin pretreatment reduced pathological liver damage, serum aminotransferase levels, serum concentrations of IL-1β, IL-18 and TNF-α in the murine IRI model. Fisetin also reduced the expression of NLRP3 inflammasome-associated proteins (NLRP3, cleaved caspase-1, IL-1β and IL-18) in I/R-operated liver. The experiments in vitro showed that fisetin decreased the release of IL-1β, IL-18 and TNF-α, and reduced the expression of NLRP3 inflammasome-associated proteins in H/R-treated RAW264.7 cells. Moreover, fisetin increased the expressions of p-GSK3β and p-AMPK in both models, indicating that its anti-inflammatory effects were dependent on GSK3β/AMPK signaling. The anti-inflammatory effects of fisetin were partially inhibited by the AMPK specific inhibitor compound C.

CONCLUSIONS

Fisetin showed protective effects against hepatic IRI, countering inflammatory responses through mediating the GSK3β/AMPK/NLRP3 inflammasome pathway.