LXA4 protects against hypoxic-ischemic damage in neonatal rats by reducing the inflammatory response via the IκB/NF-κB pathway

Hypoxia and the resultant decreases in cerebral blood flow in the perinatal period can lead to neonatal hypoxic-ischemic (HI) brain injury, which can, in turn, cause severe disability or even death. However, the efficacy of current treatment strategies remains limited. Several studies have demonstrated that lipoxin A4 (LXA4), as one of the earliest types of endogenous lipid mediators, can inhibit the accumulation of neutrophils, arrest inflammation, and promote the resolution of inflammation. However, research on LXA4 in the nervous system has rarely been carried out. In the present study, we sought to investigate the protective effect of LXA4 on HI brain damage in neonatal rats, as well as the underlying mechanisms. Through experiments conducted using an HI animal model, we found that the LXA4 intervention promoted the recovery of neuronal function and tissue structure following brain injury while maintaining the integrity of the blood–brain barrier in addition to reducing cerebral edema, infarct volume, and inflammatory responses. Our results suggest that LXA4 interfered with neuronal oxygen-glucose deprivation insults, reduced the expression of inflammatory factors, inhibited apoptosis, and promoted neuronal survival in vitro. Finally, the LXA4 intervention attenuated HI-induced activation of inhibitor kappa B (IκB) and degradation of nuclear factor-κB (NF-κB). In conclusion, our data suggest that LXA4 exerts a neuroprotective effect against neonatal HI brain damage through the IκB/NF-κB pathway. Our findings will help inform future studies regarding the effects of LXA4 on neuroinflammation, blood–brain barrier integrity, and neuronal apoptosis.     

Sirt1 overexpression protects murine osteoblasts against TNF-α-induced injury in vitro by suppressing the NF-κB signaling pathway

Aim:

Sirtuin 1 (Sirt1) is the class III histone/protein deacetylase that interferes with the NF-κB signaling pathway, thereby has anti-inflammatory function. This study was undertaken to investigate whether Sirt1 could protect osteoblasts against TNF-α-induced injury in vitro.

Methods:

Murine osteoblastic cell line, MC3T3-E1, was used. Overexpress of Sirt1 protein in MC3T3-E1 cells was made by transfection the cells with Sirt1-overexpressing adenovirus. The levels of mRNAs and proteins were determined with qRT-PCR and Western blotting, respectively. The activity of NF-κB was examined using NF-κB luciferase assay. The NO concentration was measured using the Griess method.

Results:

Treatment of MC3T3-E1 cells with TNF-α (2.5–10 ng/mL) suppressed Sirt1 protein expression in a concentration-dependent manner. TNF-α (5 ng/mL) resulted in an increase in apoptosis and a reduction in ALP activity in the cells. Overexpression of Sirt1 in the cells significantly attenuated TNF-α-induced injury through suppressing apoptosis, increasing ALP activity, and increasing the expression of Runx2 and osteocalcin mRNAs. Furthermore, overexpression of Sirt1 in the cells significantly suppressed TNF-α-induced NF-κB activation, followed by reducing the expression of iNOS and NO formation. Sirt1 activator resveratrol (10 μmol/L) mimicked the protection of the cells by Sirt1 overexpression against TNF-α-induced injury, which was reversed by the Sirt1 inhibitor EX-527 (5 μmol/L).

Conclusion:

Overexpression of Sirt1 protects MC3T3-E1 osteoblasts aganst TNF-α-induced cell injury in vitro, at least in part, via suppressing NF-κB signaling. Sirt1 may be a novel therapeutic target for treating rheumatoid arthritis-related bone loss.     

Crocin protects against cardiotoxicity induced by doxorubicin through TLR-2/NF-κB signal pathway in vivo and vitro

Doxorubicin (DOX) is widely used to treat multiple of tumors, but its clinical trials are allied with some serious adverse events mainly cardiac functional abnormalities. So the objective of our investigation is to identify the cardioprotective action of crocin (CRO), a natural compound derived from saffron, against DOX-induced cardiotoxicity. CRO was injected intraperitoneally (i.p.) to rats for six consecutive days and DOX (i.p.) was administered on the fourth day. H9c2 cells were treated with DOX for 24 h after being pre-treated by CRO for 2 h. CRO reduced tachycardia and J-point elevation, decreased the levels of serum creatine kinase, lactate dehydrogenase, glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase. CRO exerted positive effect on DOX-induced ROS production and changes of oxidative stress biomarkers. CRO significantly decreased intracellular Ca²⁺ concentration and increased mitochondria membrane potential in H9c2 cells. CRO also resisted the DOX-induced high expression of tumor necrosis factor-α and interleukin-6, inhibited apoptosis and improved the abnormal expression levels of Bcl-2, Bax and Caspase-3 proteins. CRO obviously restrained DOX-mediated high expression of toll-like receptor-2 (TLR-2) and nuclear factor kappa-B (NF-κB) in ventricular tissue. In brief, CRO distinctly restrained DOX-mediated cardiotoxicity by inhibiting oxidative stress, inflammation, apoptotic and redressing cardiomyocyte calcium dyshomeostasis and mitochondria damage. These cardioprotective effects may be related closely with the TLR2/NF-κB pathway.     

Exendin-4 protects against sulfonylurea-induced β-cell apoptosis

Sulfonylurea is one of the commonly used anti-diabetic drugs that stimulate insulin secretion from β-cells. Despite their glucose lowering effects in type 2 diabetes mellitus, long-term treatment brought on secondary failure characterized by β-cell exhaustion and apoptosis. ER stress induced by Ca(2+) depletion in endoplasmic reticulum (ER) is speculated be one of the causes of secondary failure, but it remains unclear. Glucagon like peptide-1 (GLP-1) has anti-apoptotic effects in β-cells after the induction of oxidative and ER stress. In this study, we examined the anti-apoptotic action of a GLP-1 analogue in β-cell lines and islets against ER stress induced by chronic treatment of sulfonylurea. HIT-T15 and dispersed islet cells were exposed to glibenclamide for 48 h, and apoptosis was evaluated using Annexin/PI flow cytometry. Expression of the ER stress-related molecules and sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) 2/3 was determined by real-time PCR and western blot analysis. Chronic exposure to glibenclamide increased apoptosis by depletion of ER Ca(2+) concentration through reduced expression of SERCA 2/3. Pretreatment with Exendin-4 had an anti-apoptotic role through ER stress modulation and ER Ca(2+) replenishing by SERCA restoration. These findings will further the understanding of one cause of glibenclamide-induced β-cell loss and therapeutic availability of GLP-1-based drugs in secondary failure by sulfonylurea during treatment of diabetes.     

α-Mangostin protects lipopolysaccharide-stimulated nucleus pulposus cells against NLRP3 inflammasome-mediated apoptosis via the NF-κB pathway

Intervertebral disc degeneration (IDD) is a common and chronic inflammatory disorder. α-Mangostin exhibits a novel biological function against inflammation in various inflammatory diseases. Here, we aimed to explore the role of α-mangostin in IDD using an in vitro cell model. Human nucleus pulposus cells (NPCs) were exposed to lipopolysaccharide (LPS) to induce inflammatory injury. Cell viability of NPCs was determined by CCK-8 assay. ELISA was performed to examine the production of interleukin (IL)-1β and IL-18. Apoptotic cell death in NPCs was detected by TUNEL staining. The expression levels of apoptotic-associated proteins were detected by western blotting. Nuclear factor-kappa B (NF-κB) activation was examined by determining the expression levels of p-p65, p65, and nuclear p65. Results showed that treatment with α-mangostin improved the viability of LPS-treated NPCs. α-Mangostin treatment also inhibited the LPS-induced increase in expression levels of NLRP3, ASC and pro-caspase-1, as well as the production of IL-1β and IL-18 in NPCs. Moreover, treatment with α-mangostin or NLRP3 inhibitor (MCC950) significantly decreased apoptotic cell death in NPCs, as compared with treatment with LPS. In addition, the expression levels of cleaved caspase-3 and Bax were decreased, while Bcl-2 expression was increased in α-mangostin- or MCC950-treated NPCs. Treatment with α-mangostin also suppressed LPS-induced increase of p-p65/p65 and nuclear p65 levels. Moreover, inhibition of NF-κB by PDTC aggravated the inhibitory effects of α-mangostin on NLRP3 inflammasome activation and apoptosis in LPS-induced NPCs. These findings suggested that α-mangostin exerted a protective effect on NLRP3 inflammasome-mediated apoptosis in LPS-induced NPCs through regulating NF-κB signaling.     

Brazilin inhibits UVB-induced MMP-1/3 expressions and secretions by suppressing the NF-κB pathway in human dermal fibroblasts

Brazilin (7, 11b-dihydrobenz[b]indeno[1,2-d]pyran-3,6a,9,10 (6H)-tetrol), the major component of Caesalpinia sappan L., is a natural red pigment used for histological staining. Recent studies have shown that brazilin exhibits distinct biological effects, including anti-hepatotoxicity, antiplatelet activity, and anti-inflammatory activities. In the present study, we evaluated the effects of brazilin on MMP-1 and -3 expressions in human dermal fibroblasts exposed to ultraviolet B (UVB) irradiation. Brazilin showed protective effect on UVB-induced loss of cell viability of fibroblasts. Brazilin also blocked significantly UVB-induced Reactive Oxygen Species generation in fibroblasts. Brazilin inhibited UVB-induced MMP-1/3 expressions and secretions in a dose-dependent manner. Moreover, UVB-induced NF-κB activation was completely blocked by treatment with brazilin. These findings suggest that brazilin inhibits UVB-induced MMP-1/3 expressions and secretions by suppressing of NF-κB activation in human dermal fibroblasts. Thus, brazilin might be used as a potential agent for treatment of UV-induced skin photoaging.     

β-Patchoulene from patchouli oil protects against LPS-induced acute lung injury via suppressing NF-κB and activating Nrf2 pathways

β-Patchoulene (β-PAE), a tricyclic sesquiterpene isolated from the essential oil of the leaves and stems of Pogostemon cablin (Blanco) Benth., has been reported to have potent anti-inflammatory activity. The aim of this study was to evaluate the potential protective effect of β-PAE on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. ALI was induced by intracheal instillation of LPS into lung, and dexamethasone (DEX) was used as a positive control. Results indicated that pretreatment with β-PAE significantly decreased the mortality rate of mice and lung W/D weight ratio, ameliorated lung pathological changes as compared to model group. Meanwhile, β-PAE pretreatment markedly inhibited the increase of TNF-α, IL-6 and IL-1β secretions in the bronchoalveolar lavage fluid, and prevented LPS-induced elevations of MPO activity and MDA level in the lung. Additionally, β-PAE pretreatment significantly elevated miR-146a expression and suppressed the LPS-induced activation of NF-κB and expression of its mediated genes (TNF-α, IL-6 and IL-1β). β-PAE was also observed to markedly upregulate the Nrf2 and HO-1 expression and activate the antioxidant genes (NQO-1, GCLC and HO-1). Taken together, β-PAE possessed protective effect against LPS-induced ALI, which might be associated with its differential regulation of NF-κB and Nrf2 activities and up-regulation of expression of miR-146a. The results rendered β-PAE a promising anti-inflammatory agent worthy of further development into a pharmaceutical drug for the treatment of ALI.     

Puerarin protects against myocardial ischemia/reperfusion injury by inhibiting inflammation and the NLRP3 inflammasome: The role of the SIRT1/NF-κB pathway

AimsThe purpose of this study was to investigate the protective effects of puerarin and elucidate the underlying mechanisms of puerarin in myocardial ischemia/reperfusion (MI/R) injury.Main methodsC57BL/6 mice were exposed to puerarin (100 mg/kg) with or without the SIRT1 inhibitor nicotinamide (500 mg/kg) and then subjected to MI/R operation. Myocardial infarct size, serum creatine kinase-MB (CK-MB) activity, apoptotic cell death, and cardiac structure and function were examined to evaluate MI/R injury. RT-PCR and western blotting were used to determine the inflammatory response and inflammasome activation, as well as activation of SIRT1/NF-κB pathway.ResultsPuerarin significantly reduced myocardial infarct size, serum CK-MB activity, and apoptotic cell death, and improved cardiac structural damage and dysfunction. Moreover, puerarin notably decreased the mRNA and protein levels of TNF-α, IL-6, and IL-1β, indicating that puerarin attenuated MI/R-induced inflammation. Furthermore, puerarin markedly decreased the protein levels of Ac-NF-κB, NLRP3, cleaved caspase-1, cleaved IL-1β, and cleaved IL-18 and increased the protein level of SIRT1. More importantly, the SIRT1 inhibitor nicotinamide prevented these puerarin-induced cardioprotective effects and regulation of the SIRT1/NF-κB pathway, as well as the NLRP3 inflammasome activation.ConclusionPuerarin protected against MI/R injury by inhibiting inflammatory responses probably via the SIRT1/NF-κB pathway, and inhibition of the NLRP3 inflammasome was also involved in puerarin-induced cardioprotective effects. These results suggest that puerarin may be a novel candidate for the treatment of ischemic heart disease.     

Tricin 7-glucoside protects against experimental cerebral ischemia by reduction of NF-κB and HMGB1 expression

There have been several studies of nuclear factor-κB (NF-κB) and high-mobility group box1 (HMGB1) associated with the pathophysiology of cerebral ischemia. Tricin 7-glucoside, a major bioactive compound extracted from Sedum sarmentosum Bunge. The objectives of this study were to determine the effects of Tricin 7-glucoside on a cultured neuronal cell line, SH-SY5Y in vitro and experimental ischemic stroke in vivo. For oxygen-glucose deprivation (OGD) and tumor necrosis factor-α (TNF-α) stimulated SH-SY5Y cell line in vitro, SH-SY5Y cells were incubated with Tricin 7-glucoside. For in vivo experiment, rats were subjected to middle cerebral artery occlusion (MACO) for 1h, then followed by reperfusion for 23 h. Treatment of SH-SY5Y cells with Tricin 7-glucoside reduced the OGD-induced apoptosis and cytotoxicity, blocked TNF-α-induced NF-κB and IκB-α phosphorylation, and decreased HMGB1 expression. At doses higher than 50mg/kg, Tricin 7-glucoside produced a significant neuroprotective potential in rats with ischemia and reperfusion (I/R). Tricin 7-glucoside (100mg/kg) demonstrated significant neuroprotective activity even after delayed administration at 2h and 4h after I/R. Tricin 7-glucoside 100mg/kg attenuated histopathological damage, decreased brain edema, inhibited NF-κB activation and reduced HMGB1 expression. These data show that Tricin 7-glucoside protects brain against I/R injury with a favorable therapeutic time-window by alleviating cerebral I/R injury and attenuating blood-brain barrier (BBB) breakdown, and its protective effects may involve HMGB1 and NF-κB signaling pathway.     

Parthenolide,an NF-κB inhibitor,alleviates peritoneal fibrosis by suppressing the TGF-β/Smad pathway

Transforming growth factor (TGF)-β/Smad signalling plays a central role in the pathogenesis of peritoneal fibrosis related to peritoneal dialysis (PD). Parthenolide (PTL), a naturally occurring phytochemical, is isolated from the shoots of feverfew (Tanacetum parthenium) and displays analgesia, anti-inflammation and anticancer activities. In this study, we examined the therapeutic potential of PTL on PD-related peritoneal fibrosis induced by daily intraperitoneal injection of 4.25% dextrose-containing PD fluid (PDF) in vivo and TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro. PTL was administered daily before PDF injection or after 14 days of PDF injection. Both PTL treatments showed a protective effect on peritoneal fibrosis and prevented peritoneal dysfunction. Similarly, PTL suppressed the expression of fibrotic markers (fibronectin and collagen I) and restored the expression of the epithelial marker (E-cadherin) in TGF-β1-treated HMrSV5 cells. Furthermore, PTL inhibited TGF-β1-induced Smad2 and Smad3 phosphorylation and nuclear translocation but did not influence Smad1/5/9 phosphorylation or activate other downstream signalling pathways of TGF-β1, including AKT, extracellular signal-regulated kinase (ERK) or p38. In conclusion, PTL treatment may represent an effective and novel therapy for PD-associated peritoneal fibrosis by suppressing the TGF-β/Smad pathway.     

FKBP51 and the NF-κB regulatory pathway in cancer

Constitutive activation of NF-κB occurs in a significant percentage of human cancers. Genetic abnormalities of tumors often enhance normal NF-κB signaling. Chronic inflammation is also associated with constitutive NF-κB activation and increases the risk of cancer. Aberrant NF-κB activation favors cellular transformation, sustains cancer survival, and contributes to tumor invasion. Strategies to inhibit NF-κB represent a promising therapeutic option against cancer. In the last decade, several studies point to the large immunophilin FKBP51 as an important element for the control of NF-κB activation in human neoplasia. This article is an overview of the causes of aberrant NF-κB regulation in cancer and highlights recent papers that implicate FKBP51 in such deregulation.     

Effect of iNOS and NF-κB gene silencing on β-cell survival and function

Purpose: Type I diabetes results from β-cell death and dysfunction, induced by infiltration of immune cells and local production of inflammatory cytokines. Therefore, we investigated the effect of iNOS and NF-κB gene silencing on β-cell survival and function.

Methods: Rat insulinoma INS-1E cells were transfected with chemically synthesized siRNA after complex formation with Lipofectamine 2000. Cells were then treated with a cocktail of inflammatory cytokines (IL-1β+ TNF-α+ IFN-α), and glucose stimulated-insulin response and viability were determined. iNOS and NF-κB gene expression was assessed at mRNA level by real time RT-PCR. The effect of gene silencing was also correlated with cytokine-induced NO production and apoptosis.

Results: Transfection of INS-1E cells with siRNAs silenced iNOS and NF-κB gene expression and reduced NO production in a sequence-specific manner without causing significant loss of cell viability and function. However, the abrogation of NO production did not prevent INS-1E cells from cytokine-induced apoptosis, suggesting that this event may not be totally dependent on NO production.

Conclusion: The gene silencing approach presented here is capable of attenuating the effects of inflammatory cytokines, such as iNOS expression and NO production and it will help to identify new target genes to improve islet transplantation.     

Saikosaponin a and its epimer saikosaponin d exhibit anti-inflammatory activity by suppressing activation of NF-κB signaling pathway

Saikosaponin a (SSa) and its epimer saikosaponin d (SSd) are major triterpenoid saponin derivatives from Radix bupleuri (RB), which has been long used in Chinese traditional medicine for treatment of various inflammation-related diseases. In the present study, the anti-inflammatory activity, as well as the underlying mechanism, of SSa and SSd was investigated in lipopolysaccharide (LPS)-induced RAW264.7 cells. Our results demonstrated that both SSa and SSd significantly inhibited the expression of inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-induced RAW264.7 cells, and finally resulted in the reduction of nitric oxide (NO) and prostaglandin E(2) (PGE(2)). In addition, LPS-induced production of major pro-inflammatory cytokines: the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), was suppressed in a dose-dependent manner by the treatment of SSa or SSd in RAW264.7 cells. Further analysis revealed that both SSa and SSd could inhibit translocation of nuclear factor-κB (NF-κB) from the cytoplasm to the nucleus in the LPS-induced RAW264.7 cells. Furthermore, SSa and SSd exhibited significant anti-inflammatory activity in two different murine models of acute inflammation, carrageenan-induced paw edema in rats and acetic acid-induced vascular permeability in mice. In conclusion, SSa and SSd showed potent anti-inflammatory activity through inhibitory effects on NF-κB activation and thereby on iNOS, COX-2 and pro-inflammatory cytokines.     

Hydrangenol inhibits lipopolysaccharide-induced nitric oxide production in BV2 microglial cells by suppressing the NF-κB pathway and activating the Nrf2-mediated HO-1 pathway

We previously demonstrated the anti-inflammatory effect of water extract of Hydrangea macrophylla in lipopolysaccharide (LPS)-stimulated macrophage cells. Here, we investigated whether hydrangenol, a bioactive component of H. macrophylla, attenuates the expression of nitric oxide (NO) and its associated gene, inducible NO synthase (iNOS), in LPS-stimulated BV2 microglial cells. Our data showed that low dosages of hydrangenol inhibited LPS-stimulated NO release and iNOS expression without any accompanying cytotoxicity. Hydrangenol also suppressed LPS-induced nuclear translocation of nuclear factor-κB (NF-κB) subunits, consequently inhibiting DNA-binding activity of NF-κB. Additionally, the NF-κB inhibitors, pyrrolidine dithiocarbamate (PDTC) and PS-1145, significantly attenuated LPS-induced iNOS expression, indicating that hydrangenol-induced NF-κB inhibition might be a key regulator of iNOS expression. Furthermore, our data showed that hydrangenol suppresses NO production by inducing heme oxygenase-1 (HO-1). The presence of cobalt protoporphyrin, a specific HO-1 inducer, potently suppressed LPS-induced NO production. Hydrangenol also promoted nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and subsequently increased its binding activity at the specific antioxidant response element sites. Additionally, transient knockdown of Nrf2 significantly downregulated hydrangenol-induced HO-1 expression, indicating that hydrangenol-induced Nrf2 is an upstream regulator of HO-1. Taken together, these data suggest that hydrangenol attenuates NO production and iNOS expression in LPS-stimulated BV2 microglial cells by inhibiting NF-κB activation and by stimulating the Nrf2-mediated HO-1 signaling pathway. Therefore, hydrangenol is a promising therapeutic agent for treatment of LPS-mediated inflammatory diseases.     

Depression of glucose levels and partial restoration of pancreatic β-cell damage by melatonin in streptozotocin-induced diabetic rats

Diabetes mellitus is a common but serious metabolic disorder associated with many functional and structural complications. Glucose metabolism is disturbed due to an absolute or relative insulin deficiency. The experiment was carried out to determine the effect of melatonin on blood glucose and insulin concentrations, and histopathology of pancreatic β-cells in streptozotocin (STZ)-induced diabetic rats. The rats were randomly allocated into one of the four experimental groups: group A (control), group B (diabetic untreated), group C (diabetic treated with melatonin for 6 weeks) and group D (diabetic treated with melatonin for 8 weeks); each group contained ten animals. Diabetes was induced in B, C and D groups by a single intraperitoneal (i.p.) injection of STZ (50 mg/kg, freshly dissolved in 5 mmol/l citrate buffer, pH 4.5). The rats in melatonin-treated groups were subjected to the daily i.p injection of 10 mg kg⁻¹ of melatonin for 6 or 8 weeks starting the day after STZ injection. Control and diabetic untreated rats were injected with the same volume of isotonic NaCl as the melatonin treated groups. Almost all insulin-positive β-cells were degranulated, degenerated or necrotic in the STZ-treated rats leading to decrease in insulin secretion and an increase in blood glucose concentration. Melatonin treatment caused a sharp decrease in the elevated serum glucose, a slight increase in the lowered serum insulin concentrations and small partial regeneration/proliferation of β-cells of islets. It is concluded that the hypoglycemic action of melatonin could be partly due to small amelioration in the β-cells of pancreatic islets causing a slight increase in insulin secretion, it is mostly due to the extrapancreatic actions of the melatonin.     

Carvacrol protects neuroblastoma SH-SY5Y cells against Fe2+-induced apoptosis by suppressing activation of MAPK/JNK-NF-κB signaling pathway

Aim:

Carvacrol (2-methyl-5-isopropylphenol), a phenolic monoterpene in the essential oils of the genera Origanum and Thymus, has been shown to exert a variety of therapeutic effects. Here we examined whether carvacrol protected neuroblastoma SH-SY5Y cells against Fe²⁺-induced apoptosis and explored the underlying mechanisms.

Methods:

Neuroblastoma SH-SY5Y cells were incubated with Fe²⁺ for 24 h, and the cell viability was assessed with CCK-8 assay. TUNEL assay and flow cytometric analysis were performed to evaluate cell apoptosis. The mRNA levels of pro-inflammatory cytokines and NF-κB p65 were determined using qPCR. The expression of relevant proteins was determined using Western blot analysis or immunofluorescence staining.

Results:

Treatment of SH-SY5Y cells with Fe²⁺ (50–200 μmol/L) dose-dependently decreased the cell viability, which was significantly attenuated by pretreatment with carvacrol (164 and 333 μmol/L). Treatment with Fe²⁺ increased the Bax level and caspase-3 activity, and decreased the Bcl-2 level, resulting in cell apoptosis. Furthermore, treatment with Fe²⁺ significantly increased the gene expression of IL-1β, IL-6 and TNF-α, and induced the nuclear translocation of NF-κB. Treatment with Fe²⁺ also significantly increased the phosphorylation of p38, ERK, JNK and IKK in the cells. Pretreatment with carvacrol significantly inhibited Fe²⁺-induced activation of NF-κB, expression of the pro-inflammatory cytokines, and cell apoptosis. Moreover, pretreatment with carvacrol inhibited Fe²⁺-induced phosphorylation of JNK and IKK, but not p38 and ERK in the cells.

Conclusion:

Carvacrol protects neuroblastoma SH-SY5Y cells against Fe²⁺-induced apoptosis, which may result from suppressing the MAPK/JNK-NF-κB signaling pathways.     

Protective effect of forsythoside B against lipopolysaccharide-induced acute lung injury by attenuating the TLR4/NF-κB pathway

Acute lung injury (ALI), which is mainly triggered by infection, pneumonia, vasculitis, and sepsis, has no specific and effective therapy except for primary supportive treatment or bedside care. Excessive inflammation caused by innate immune cells is the major characteristic of ALI. Forsythoside B, a phenylethanoside compound, possesses good antioxidant and anti-bacterial properties in vivo and in vitro. In this study, the therapeutic potential of forsythoside B and its mechanism of action were investigated in a lipopolysaccharide (LPS)-induced ALI mouse model. The results showed that LPS-induced edema exudation and lung pathological changes in mice were significantly suppressed by forsythoside B pre-treatment. Furthermore, it also attenuated lung inflammation caused by LPS stimulation, evidenced by decreased inflammatory cell infiltration and down-regulated expression of cytokines, chemokines, and inducible enzymes. The anti-inflammation property of forsythoside B was confirmed in vitro using LPS-stimulated RAW 264.7 macrophages. Moreover, it alleviated LPS-induced inflammation by inhibiting the activation of TLR4/NF-κB signaling pathway in vivo and in vitro. In conclusion, the results demonstrated that forsythoside B protects against LPS-induced ALI by attenuating inflammatory cell infiltration and suppressing TLR4/NF-κB-mediated lung inflammation. Therefore, it might be a potential therapeutic agent for ALI caused by sepsis.