Blocking Parkin/PINK1-mediated mitophagy sensitizes hepatocellular carcinoma cells to sanguinarine-induced mitochondrial apoptosis

Hepatocellular carcinoma (HCC) remains a major clinical challenge. Although mitophagy is implicated in hepatocarcinogenesis, novel therapeutic options targeting mitophagy for HCC treatment still await further studies. Here, we demonstrate that sanguinarine induces cell death in HCC cell line MHCC-97H through the mitochondrial apoptosis pathway. Sanguinarine triggers mitochondrial dysfunction and PTEN-induced putative kinase 1 (PINK1)/Parkin upregulation and recruitment to mitochondria. Elevated levels of p62 and LC3-II/I ratios suggest that sanguinarine is both an inducer of autophagy and a blocker of autolysosome formation, which is further confirmed by LC3-II conversion levels in presence of autophagy and mitophagy inhibitors, as well as an autophagy activator. In addition, blocking autophagy promotes sanguinarine-induced cell death, indicating mitophagy plays a cytoprotective role in sanguinarine-treated cells. Our findings suggest that blocking mitophagy may contribute to sanguinarine-induced mitochondrial apoptosis through the prevention of damaged mitochondrial clearance.     

PINK1/Parkin-mediated mitophagy play a protective role in manganese induced apoptosis in SH-SY5Y cells

Manganese (Mn) as an environmental risk factor of Parkinson's disease (PD) is considered to cause manganism. Mitophagy is thought to play a key role in elimination the injured mitochondria. The goal of this paper was to explore whether the PINK1/Parkin-mediated mitophagy is activated and its role in Mn-induced mitochondrial dysfunction and cell death in SH-SY5Y cells. Here, we investigated effects of MnCl₂ on ROS generation, mitochondrial membrane potential (MMP/ΔΨ_m) and apoptosis by FACS and examined PINK1/Parkin-mediated mitophagy by western-blotting and the co-localization of mitochondria and acidic lysosomes. Further, we explore the role of mitophagy in Mn-induced apoptosis by inhibition the mitophagy by knockdown Parkin level. Results show that MnCl₂ dose-dependently caused ΔΨ_m decrease, ROS generation and apoptosis of dopaminergic SH-SY5Y cells. Moreover, Mn could induce mitophagy and PINK1/Parkin-mediated pathway was activated in SH-SY5Y cells. Transient transfection of Parkin siRNA knockdown the expressing level of parkin inhibited Mn-induced mitophagy and aggravated apoptosis of SH-SY5Y cells. In conclusion, our study demonstrated that Mn may induce PINK1/Parkin-mediated mitophagy, which may exert significant neuro-protective effect against Mn-induced dopaminergic neuronal cells apoptosis.     

High-content analysis for mitophagy response to nanoparticles: A potential sensitive biomarker for nanosafety assessment

Mitophagy, a selective autophagy of mitochondria, clears up damaged mitochondria to maintain cell homeostasis. We performed high-content analysis (HCA) to detect the increase of PINK1, an essential protein controlling mitophagy, in hepatic cells treated with several nanoparticles (NPs). PINK1 immunofluorescence-based HCA was more sensitive than assays and detections for cell viability and mitochondrial functions. Of which, superparamagnetic iron oxide (SPIO)-NPs or graphene oxide-quantum dots (GO-QDs) was selected as representatives for positive or negative inducer of mitophagy. SPIO-NPs, but not GO-QDs, activated PINK1-dependent mitophagy as demonstrated by recruitment of PARKIN to mitochondria and degradation of injured mitochondria. SPIO-NPs caused the loss of mitochondrial membrane potential, decrease in ATP, and increase in mitochondrial reactive oxide species and Ca²⁺. Blocking mitophagy with PARKIN siRNA aggravated the cytotoxicity of SPIO-NPs. Taken together, PINK1 immunofluorescence-based HCA is considered to be an early, sensitive, and reliable approach to evaluate the bioimpacts of NPs.     

Synergistic effects of autophagy/mitophagy inhibitors and magnolol promote apoptosis and antitumor efficacy

Mitochondria as a signaling platform play crucial roles in deciding cell fate. Many classic anticancer agents are known to trigger cell death through induction of mitochondrial damage. Mitophagy, one selective autophagy, is the key mitochondrial quality control that effectively removes damaged mitochondria. However, the precise roles of mitophagy in tumorigenesis and anticancer agent treatment remain largely unclear. Here, we examined the functional implication of mitophagy in the anticancer properties of magnolol, a natural product isolated from herbal Magnolia officinalis. First, we found that magnolol induces mitochondrial depolarization, causes excessive mitochondrial fragmentation, and increases mitochondrial reactive oxygen species (mtROS). Second, magnolol induces PTEN-induced putative kinase protein 1 (PINK1)‒Parkin-mediated mitophagy through regulating two positive feedforward amplification loops. Third, magnolol triggers cancer cell death and inhibits neuroblastoma tumor growth via the intrinsic apoptosis pathway. Moreover, magnolol prolongs the survival time of tumor-bearing mice. Finally, inhibition of mitophagy by PINK1/Parkin knockdown or using inhibitors targeting different autophagy/mitophagy stages significantly promotes magnolol-induced cell death and enhances magnolol's anticancer efficacy, both in vitro and in vivo. Altogether, our study demonstrates that magnolol can induce autophagy/mitophagy and apoptosis, whereas blockage of autophagy/mitophagy remarkably enhances the anticancer efficacy of magnolol, suggesting that targeting mitophagy may be a promising strategy to overcome chemoresistance and improve anticancer therapy.     

Garciesculenxanthone B induces PINK1-Parkin-mediated mitophagy and prevents ischemia-reperfusion brain injury in mice

Mitophagy is a selective form of autophagy involving the removal of damaged mitochondria via the autophagy-lysosome pathway.PINK1-Parkin-mediated mitophagy is one of the most important mechanisms in cardiovascular disease,cerebral ischemia-reperfusion(I/R)injury,and neurodegenerative diseases.In this study we conducted an image-based screening in YFP-Parkin HeLa cells to discover new mitophagy regulators from natural xanthone compounds.We found that garciesculenxanthone B(GeB),a new xanthone compound from Garcinia esculenta,induced the formation of YFP-Parkin puncta,a well known mitophagy marker.Furthermore,treatment with GeB dose-dependently promoted the degradation of mitochondrial proteins Tom20,Tim23,and MFN1 in YFP-Parkin HeLa cells and SH-SY5Y cells.We revealed that GeB stabilized PINK1 and triggered Parkin translocation to the impaired mitochondria to induce mitophagy,and these effects were abolished by knockdown of PINK1.Finally,in vivo experiments demonstrated that GeB partially rescued ischemia-reperfusion-induced brain injury in mice.Taken together,our findings demonstrate that the natural compound GeB can promote the PINK1-Parkin-mediated mitophagy pathway,which may be implicated in protection against I/R brain injury.     

Baicalin mitigated IL-1β-Induced osteoarthritis chondrocytes damage through activating mitophagy

Mitophagy is related to chondrocyte homeostasis and plays a key role in the progress of osteoarthritis (OA). Baicalin has a protective effect on OA chondrocytes, the aim of this study was to explore whether the effect of Baicalin on IL-1β-induced chondrocyte injury is related to the regulation of mitophagy. The expression of collagen II in chondrocytes was detected to identify chondrocytes. The effects of different concentrations of Baicalin (10, 20 and 40 μM), autophagy inhibitor (3-Methyladenine), autophagy activator (rapamycin) and Baicalin combined with PI3K agonist (740Y-P) on the viability (cell counting kit 8), apoptosis (flow cytometry), autophagy activation (Monodansylcadaverine staining) and mitochondrial membrane potential (JC-1 kit) of IL-1β-induced chondrocytes were evaluated. The co-localization of autophagosome and mitochondria was determined by immunofluorescence. Apoptosis-, autophagy-, PI3K/AKT/mTOR pathway- and mitophagy-related proteins were detected by western blot. Our result revealed that Baicalin and rapamycin facilitated cell viability, autophagy and mitophagy, elevated mitochondrial membrane potential and suppressed apoptosis of IL-1β-induced rat chondrocytes. In addition, Baicalin and rapamycin upregulated the levels of Bcl-2, Beclin 1, LC3-II/LC3-I, p-Drp1, PINK1 and Parkin as well as downregulated the levels of Bax, cleaved caspase-3, P62, p-PI3K/PI3K, p-mTOR/mTOR and Drp1 in IL-1β-induced rat chondrocytes. However, 3-Methyladenine did the opposite effects of Baicalin and 740Y-P reversed the effects of Baicalin on IL-1β-induced rat chondrocytes. In conclusion, Baicalin activated mitophagy in IL-1β-induced chondrocytes by inhibiting PI3K/AKT/mTOR pathway and activating PINK1/Parkin and PINK1/Drp-1 pathway, thereby reducing the chondrocyte injury.     

Histone deacetylase inhibitors inhibit cervical cancer growth through Parkin acetylation-mediated mitophagy

Parkin, an E3 ubiquitin ligase, plays a role in maintaining mitochondrial homeostasis through targeting damaged mitochondria for mitophagy. Accumulating evidence suggests that the acetylation modification of the key mitophagy machinery influences mitophagy level, but the underlying mechanism is poorly understood. Here, our study demonstrated that inhibition of histone deacetylase (HDAC) by treatment of HDACis activates mitophagy through mediating Parkin acetylation, leading to inhibition of cervical cancer cell proliferation. Bioinformatics analysis shows that Parkin expression is inversely correlated with HDAC2 expression in human cervical cancer, indicating the low acetylation level of Parkin. Using mass spectrometry, Parkin is identified to interact with two upstream molecules, acetylase acetyl-CoA acetyltransferase 1 (ACAT1) and deacetylase HDAC2. Under treatment of suberoylanilide hydroxamic acid (SAHA), Parkin is acetylated at lysine residues 129, 220 and 349, located in different domains of Parkin protein. In in vitro experiments, combined mutation of Parkin largely attenuate the interaction of Parkin with PTEN induced putative kinase 1 (PINK1) and the function of Parkin in mitophagy induction and tumor suppression. In tumor xenografts, the expression of mutant Parkin impairs the tumor suppressive effect of Parkin and decreases the anticancer activity of SAHA. Our results reveal an acetylation-dependent regulatory mechanism governing Parkin in mitophagy and cervical carcinogenesis, which offers a new mitophagy modulation strategy for cancer therapy.     

Genetic mutations and functions of PINK1

Parkinson's disease (PD) is the second most common neurodegenerative disease. Mutations in PINK1 (PARK6) are the second most frequent cause of autosomal recessive, young-onset PD, after parkin (PARK2). PINK1 (a kinase with an N-terminal mitochondrial targeting sequence) provides protection against mitochondrial dysfunction and regulates mitochondrial morphology via fission/fusion machinery. PINK1 also acts upstream of parkin (a cytosolic E3 ubiquitin ligase) in a common pathway. Recent studies have described PINK1/parkin function in the maintenance of mitochondrial quality via autophagy (mitophagy). PINK1/parkin-mediated mitophagy provides new insights into the etiology of PD and could be a suitable target for new treatment of PD. In this review, we discuss the molecular genetics and functions of PINK1, which could be key factors in novel rational therapy for sporadic PD as well as PINK1-linked PD.     

Melatonin prevents blood-retinal barrier breakdown and mitochondrial dysfunction in high glucose and hypoxia-induced in vitro diabetic macular edema model

Diabetic macular edema (DME) is a leading cause of blindness in diabetic retinopathy. Prolonged hyperglycemia plus hypoxia contributes to DME pathogenesis. Retinal pigmented epithelial cells comprise the outer blood-retinal barrier and are essential for maintaining physiological functioning of the retina. Melatonin acts as an antioxidant and regulator of mitochondrial bioenergetics and has a protective effect against ocular diseases. However, the role of mitochondrial dysfunction and the therapeutic potential of melatonin in DME remain largely unexplored. Here, we used an in vitro model of DME to investigate blood-retinal barrier integrity and permeability, angiogenesis, mitochondrial dynamics, and apoptosis signaling to evaluate the potential protective efficacy of melatonin in DME. We found that melatonin prevents cell hyper-permeability and outer barrier breakdown by reducing HIF-1α, HIF-1β and VEGF and VEGF receptor gene expression. In addition, melatonin reduced the expression of genes involved in mitochondrial fission (DRP1, hFis1, MIEF2, MFF), mitophagy (PINK, BNip3, NIX), and increased the expression of genes involved in mitochondrial biogenesis (PGC-1α, NRF2, PPAR-γ) to maintain mitochondrial homeostasis. Moreover, melatonin prevented apoptosis of retinal pigmented epithelial cells. Our results suggest that mitochondrial dysfunction may be involved in DME pathology, and melatonin may have therapeutic value in DME, by targeting signaling in mitochondria.     

PINK1/Parkin-mediated mitophagy is involved in NaAsO2-induced apoptosis of human hepatic cells through activation of ERK signaling

Mitochondrial dysfunction has been demonstrated as one key event in arsenic-induced hepatic cell damage though the exact molecular target remains unknown. Here we examined NaAsO₂-induced mitochondrial damage in the L-02 cell led to mitochondrial depolarization and cytochrome c release, mitophagy, apoptosis in a dose response manner. Mitophagy was measured by analysis of PINK1, Parkin, LC3-II and p62 protein. Apoptosis was assessed by measuring Annexin V. Using the mitophagy inhibitor cyclosporine A (CsA) or ERK inhibitor (PD98059), the balance between mitophagy and apoptosis were further explored. When CsA was used prior to cell exposure to NaAsO₂, it was found that the levels of mitophagy were decreased as expected and apoptosis was increased in response. CsA alone had no effect on the apoptosis rate. When the ERK signaling inhibitor PD98059 was used, there was a similar result that mitophagy was reduced though in contrast with CsA the apoptosis rate was also decreased compared with NaAsO₂ alone. This result, along with the increased levels of ERK measured here in response to NaAsO₂, indicates that ERK activation is a second key molecular response to NaAsO₂ through the activation of both apoptosis and mitophagy. Thus the results with CsA indicate that the likely key biological event in NaAsO₂ toxicity is at the level of the mitochondria leading to cytochrome c release and apoptosis. Mitophagy is increased in response to a secondary effect of NaAsO₂ on ERK signaling that activates both mitophagy and apoptosis. The activation of mitophagy allows the cell to avoid some apoptosis. When ERK signaling is inhibited by PD98059 both the levels of apoptosis and mitophagy are decreased compared with the response produced by NaAsO₂ alone in comparison to the inhibition of mitophagy by CsA that reduced mitophagy but dramatically increased apoptosis in response.     

Cadmium induces mitophagy through ROS-mediated PINK1/Parkin pathway

Context and objective: Recent reports have highlighted the relationship between cadmium (Cd) and autophagy, however, whether Cd can activate mitophagy remains enigmatic. This study aims to investigate the effects of Cd on mitophagy and its potential mechanism.

Methods: Mice were intraperitoneally injected with Cd for 3?d. Mitochondrial membrane potential (MMP), mitophagosomes, LC3-II/LC3-I ratio, PINK1 level and mitochondrial mass were evaluated to indicate the effects of Cd on mitophagy. To elucidate the mechanism, reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC) or acetyl-l-carnitine (ALC) as well as the mitophagy inhibitor cyclosporine A (CsA) were introduced to verify the role of ROS in mitophagy.

Results and conclusions: The results showed that Cd significantly induced MMP collapse and typical mitophagosomes formation, increased LC3-II/LC3-I ratio and PINK1 level, and decreased mitochondrial mass, revealing that Cd could induce mitophagy. However, NAC or ALC pretreatment markedly decreased Cd-induced ROS and simultaneously rescued MMP and mitochondrial mass, suggesting ROS played a crucial role in regulating mitophagy. NAC or ALC also dramatically lessened PINK1 level and mitochondrial accumulation of Parkin, indicating that ROS were related to PINK1/Parkin pathway. Notably, CsA compromised Cd-induced mitophagy, PINK1 accumulation and Parkin translocation while failed to block ROS increase, suggesting ROS functioned as an upstream signal for PINK1/Parkin pathway. Taken together, the results indicated that Cd induced ROS-mediated mitophagy through PINK1/Parkin pathway in kidneys of mice. The present study proposes a new perspective to evaluate the nephrotoxicity and its molecular mechanism under Cd exposure in vivo.     

Improvement Characteristics of Bio-active Materials Coated Fabric on Rat Muscular Mitochondria

This study surveys the improvement characteristics in old-aged muscular mitochondria by bio-active materials coated fabric (BMCF). To observe the effects, the fabric (10 and 30%) was worn to old-aged rat then the oxygen consumption efficiency and copy numbers of mitochondria, and mRNA expression of apoptosis- and mitophagy-related genes were verified. By wearing the BMCF, the oxidative respiration significantly increased when using the 30% materials coated fabric. The mitochondrial DNA copy number significantly decreased and subsequently recovered in a dose-dependent manner. The respiratory control ratio to mitochondrial DNA copy number showed a dose-dependent increment. As times passed, Bax, caspase 9, PGC-1α and β-actin increased, and Bcl-2 decreased in a dose-dependent manner. However, the BMCF can be seen to have had no effect on Fas receptor. PINK1 expression did not change considerably and was inclined to decrease in control group, but the expression was down-regulated then subsequently increased with the use of the BMCF in a dose-dependent manner. Caspase 3 increased and subsequently decreased in a dose-dependent manner. These results suggest that the BMCF invigorates mitophagy and improves mitochondrial oxidative respiration in skeletal muscle, and in early stage of apoptosis induced by the BMCF is not related to extrinsic death-receptor mediated but mitochondria-mediated signaling pathway.     

地塞米松诱导小鼠胸腺细胞凋亡中线粒体质量的变化

目的研究地塞米松(DEX)诱导的小鼠胸腺细胞凋亡中线粒体质量变化。方法分别设对照组(Control)和DEX组;在6 h,分别以NAO和M itotracker G reen(MG)单染流式细胞术检测线粒体质量变化,以D iOC6(3)染色流式细胞术检测线粒体膜电势变化,以Annexin V-PE/MG双染流式细胞术检测细胞凋亡中线粒体质量改变特点。结果NAO染色检测结果显示终浓度1μmol.L-1DEX可以诱导小鼠胸腺细胞线粒体心磷脂含量降低,与对照组比较P<0.01;MG染色流式细胞术结果表明DEX(P<0.01)诱导了胸腺细胞线粒体质量的降低;DEX(P<0.01)诱导线粒体膜电势依赖性D iOC6(3)在胸腺细胞中可染性下降;Annexin V-PE/MG双染流式细胞术显示,凋亡细胞中存在一定比例的低线粒体质量细胞,DEX组该群细胞多于对照组(P<0.01)。结论DEX诱导小鼠胸腺细胞凋亡中线粒体质量降低;线粒体质量评价在细胞凋亡相关药理学研究领域有应用前景。     

PINK1 overexpression protects against cerebral ischemia through Parkin regulation

Mitochondrial dynamics and function are important for cell survival regulation under stress. In this study, we report that cerebral ischemia/reperfusion (I/R) injury significantly reduced mitochondrial function through reduced PTEN‐induced kinase 1 (PINK1) expression, ATP (Adenosine triphosphate) levels, and increased oxidative stress compared to sham rats. PINK1 overexpression mice significantly improved mitochondrial function by increased mitochondrial complex I, II, and III activities and ATP levels with concomitant decline in reactive oxygen species levels. PINK1 overexpression mice after I/R injury significantly reduced apoptosis through downregulation of cytochrome c, p53 expressions compared to cerebral I/R injury rats. Furthermore, we showed from parkin siRNA studies that PINK1 regulated phosphorylation parkin is critical to the protection against cerebral I/R injury. Altogether, we show that PINK1 mediated parkin regulation is key to the protection against cerebral I/R injury through regulation of mitochondrial function and apoptosis.     

Mitochondrial quality control mechanisms as molecular targets in cardiac ischemia–reperfusion injury

Mitochondrial damage is a critical contributor to cardiac ischemia/reperfusion (I/R) injury. Mitochondrial quality control (MQC) mechanisms, a series of adaptive responses that preserve mitochondrial structure and function, ensure cardiomyocyte survival and cardiac function after I/R injury. MQC includes mitochondrial fission, mitochondrial fusion, mitophagy and mitochondria-dependent cell death. The interplay among these responses is linked to pathological changes such as redox imbalance, calcium overload, energy metabolism disorder, signal transduction arrest, the mitochondrial unfolded protein response and endoplasmic reticulum stress. Excessive mitochondrial fission is an early marker of mitochondrial damage and cardiomyocyte death. Reduced mitochondrial fusion has been observed in stressed cardiomyocytes and correlates with mitochondrial dysfunction and cardiac depression. Mitophagy allows autophagosomes to selectively degrade poorly structured mitochondria, thus maintaining mitochondrial network fitness. Nevertheless, abnormal mitophagy is maladaptive and has been linked to cell death. Although mitochondria serve as the fuel source of the heart by continuously producing adenosine triphosphate, they also stimulate cardiomyocyte death by inducing apoptosis or necroptosis in the reperfused myocardium. Therefore, defects in MQC may determine the fate of cardiomyocytes. In this review, we summarize the regulatory mechanisms and pathological effects of MQC in myocardial I/R injury, highlighting potential targets for the clinical management of reperfusion.     

Mitochondrial dysfunction and neuroinflammation in Parkinson disease

Parkinson disease(PD) is an age-related neurodegenerative disease. Wide spread α-synuclein aggregation and progressive loss of dopaminergic(DA) neurons in the substantia nigra are major neuropathological hallmarks of PD. The molecular mechanisms are not well understood. In recent years, mitochondrial dysfunctionis considered to play a central role in pathogenesis and progression of PD. The parkinsonian toxins(MPTP/MPP+and rotenone)have been reported to inhibit mitochondrial complex I and lead to disturbed oxidative phosphorylation and mitochondrial dynamics, increased reactive oxygen species(ROS) production and reduced mitochondrial membrane potential, thus causing DA neuron degeneration. Mitochondrial dysfunction was also shown to elicit the aggregation of α-synuclein, which in turn interfered with mitochondrial function in a vicious cycle. In sensitive neurons, all these intracellular changes may be devastating for cell survival. On the other hand, inflammasome activation is identified as pivotal inflammatory mechanism that drives progressive DA neuropathology. Inflammasome is intracellular multiprotein complex that can be activated to trigger caspase-1 cleavage in response to neurotoxic insults. Cleaved caspase-1 further promotes the maturation of the proinflammatory cytokines, and thereby results in neuroinflammation and neuronal death. Patients with PD and preclinical PD models showed extensive activation of microglial NLRP3 inflammasome. Targeting NLRP3 inflammasome has been regarded as a potential therapeutic strategy in PD. Moreover, α-synuclein is strongly linked to inflammasome activation. NLRP3 inflammasome activation by pathological α-synuclein fibrils in mouse microglia resulted in a delayed but substantial release of cleaved IL-1β, but not IL-18. NLRP3 inhibitor abolished fibrillar α-synuclein-induced NLRP3 inflammasome activation in vitro. Inhibition of inflammasome by NLRP3 inhibitor significantly ameliorated nigrostriatalα-synuclein pathology, DA neoron degeneration and motor deficits in multiple rodent PD models. These findings suggest a bi-directional relationship between microglial inflammation and neuronal α-synuclein pathology. Roles of caspase-1 and inflammasome in α-synuclein aggregation and cell death were also reported in neuronal M17-a Syn cells. Furthermore, accumulating experimental evidence supports a complex association between mitochondria and neuroinflammation in PD. In complex I inhibitory pesticides-related PD, mitochondrial dysfunction and oxidative stress induced neuroinflammation via microglial NLRP3-dependent pathways. Mitochondria-targeted antioxidant ameliorated both mitochondrial oxidative stress and NLRP3 inflammasome activation, suggesting probable upstream role of mitochondria in inflammasome activation. This result is confirmed by two in vivo studies indicating mitochondrion-driven activation of NLRP3 inflammasome and neurotoxicity in rotenone and Mito Park mouse models of PD. Conversely, inflammatory mediators produced by activated microglia can strongly affect mitochondrial oxidative phosphorylation and ROS production, eventually leading to neurodegeneration. Additionally,functional mitophagy was shown to be vital for mitochondrial quality control. When mitophagy was impaired due to some reasons such as mutation in PD-associated genes PINK1 and parkin, accumulation of dysfunctional or damaged mitochondriamay be responsible for neuroinflammation and neurodegeneration. Collectively, the available data highlight the roles of mitochondria dysfunction and neuroinflammation in neurodegeneration of PD.Identifying crosstalk and interaction among mitochondria impairment, neuroinflammation and neurodegeneration may provide insights into the pathogenesis and eventually develop novel therapeutic approaches against PD.     

Effect of phosphodiesterase type 4 inhibitor rolipram on cyclophosphamide-induced cystitis in rats

Schisandrin is the main active ingredient isolated from the fruit of Schisandra chinensis Baill. Recent studies have demonstrated that schisandrin exhibits anti-oxidative effects in vivo. In the present study, the effect of schisandrin on plasma nitrite concentration in lipopolysaccharide (LPS)-treated mice was evaluated. It also significantly inhibited carrageenan-induced paw edema and acetic acid-induced vascular permeability in mice. Furthermore, schisandrin had a protective effect on lipopolysaccharide (LPS)-induced sepsis. In vitro, our results are the first that show that the anti-inflammatory properties of schisandrin result from the inhibition of nitric oxide (NO) production, prostaglandin E(2) (PGE(2)) release, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, which in turn results from the inhibition of nuclear factor-kappaB (NF-kappaB), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) activities in a RAW 264.7 macrophage cell line.