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1.
Journal of Central South University(Medical Sciences) ; (12): 242-251, 2023.
Article in English | WPRIM | ID: wpr-971391

ABSTRACT

Necroptosis is one of the regulated cell death, which involves receptor interacting protein kinase (RIPK) 1/RIPK3/mixed lineage kinase domain like protein (MLKL) signaling pathway. Among them, MLKL is the final execution of necroptosis. The formation of RIPK1/RIPK3/MLKL necrosome induces the phosphorylated MLKL, and the activated MLKL penetrates into the membrane bilayer to form membrane pores, which damages the integrity of the membrane and leads to cell death. In addition to participating in necroptosis, MLKL is also closely related to other cell death, such as NETosis, pyroptosis, and autophagy. Therefore, MLKL is involved in the pathological processes of various diseases related to abnormal cell death pathways (such as cardiovascular diseases, neurodegenerative diseases and cancer), and may be a therapeutic target of multiple diseases. Understanding the role of MLKL in different cell death can lay a foundation for seeking various MLKL-related disease targets, and also guide the development and application of MLKL inhibitors.


Subject(s)
Protein Kinases/metabolism , Necroptosis/physiology , Receptor-Interacting Protein Serine-Threonine Kinases , Signal Transduction , Pyroptosis , Apoptosis
2.
Chinese Journal of Pharmacology and Toxicology ; (6): 512-513, 2023.
Article in Chinese | WPRIM | ID: wpr-992193

ABSTRACT

OBJECTIVE To identify the role of mixed lineage kinase domain like protein(MLKL)in cerebral small vessel disease(CSVD)and explore the underlying mechanism.METHODS Transient bilateral common carotid artery occlusion(tBCCAO)was used to establish a mouse model of CSVD.Immunofluorescence staining and Western blotting were used to observe the expres-sions of RIPK3/MLKL signaling molecules in brain tissues at 7,14 and 28 d after tBCCAO.Open field test,rotarod test,Y-maze and novel object recognition test were used to observe the effect of MLKL knockout on cognitive func-tion after tBCCAO.Blood-brain barrier(BBB)disruption was observed by sodium fluorescein permeability test and the expressions of tight junction proteins.Immunoflu-orescence staining and Western blotting were used to detect the expression of microglia marker Iba-1,astro-cyte marker GFAP,and NLRP3/Caspase-1 signaling mol-ecules in the hippocampus of CSVD mice.ELISA was used to detect the level of inflammatory factors(TNF-α,IL-1β,IL-18)in hippocampus.RESULTS The expres-sions of RIPK3/MLKL signaling molecules increased in cortex and hippocampus after tBCCAO,especially on day 14.The expression of pMLKL mainly increased in neurons,glia cells and endothelial cells in CSVD mice.MLKL knockout improved the cognitive functions such as motor learning,spatial learning and working memory,and object recognition ability in CSVD mice.MLKL knock-out alleviated the leakage of sodium fluorescein and attenuated the down-regulation of tight junction proteins at 1 d and 14 d after tBCCAO.At 14 d after tBCCAO,MLKL knock out inhibited the activations of microglia and astrocytes,attenuated the expressions of NLRP3/cas-pase-1 molecules,and decreased the levels of inflamma-tory factors in the hippocampus of mice.CONCLUSION Genetic inhibition of MLKL exerts protective effects against cognitive impairment by ameliorating BBB dam-age and neuroinflammation in a mouse cerebral small vessel disease model.

3.
Acta Pharmaceutica Sinica ; (12): 409-418, 2022.
Article in Chinese | WPRIM | ID: wpr-922916

ABSTRACT

We investigated the ability of Dracocephalum moldavica (EPDM) flavonoids to protect human brain microvascular endothelial cells (HBMECs) from necroptosis induced by ischemia-reperfusion injury. To mimic the process of cerebral ischemia-reperfusion injury, a necroptosis model was established by treatment with the pan-cysteine aspartic acid protease (caspase) inhibitor Z-VAD-FMK combined with oxygen-glucose deprivation/re-oxygenation (OGD/R) injury using HBMECs. Cell proliferation and cytotoxicity (cell counting kit-8, CCK-8) was used to measure cell viability. A Hoechst33342/PI fluorescent double-staining method was exploited to determine the rate of cell necroptosis. A commercial kit was used to detect lactate dehydrogenase in the cell culture supernate. DCFH-DA probes, calcein AM and JC-1 probes were used to measure changes in ROS production, mitochondrial membrane permeability transformation pore (MPTP) opening and mitochondrial membrane potential (MMP), respectively. Enzyme-linked immunosorbent assay (ELISA) kits were chosen to detect the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Western blotting was used to detect necroptosis-related proteins. The results show that relative to control group, Z-VAD-FMK combined with OGD/R injury reduced cell viability, increased the necroptosis rate and the levels of LDH and ROS in HBMECs. The MPTP of the model group cells opened and the MMP reduced. TNF-α, IL-1β, and IL-6 levels were significantly elevated. Furthermore, the expression of receptor-interacting protein kinase 3 (RIP3) and mitochondrial phosphoglycerate mutase 5 (PGAM5) was significantly increased, accompanied by an increase of phosphorylated mixed-lineage kinase domain-like protein (p-MLKL)/MLKL. EPDM partially reversed the changes of the above-mentioned factors in HBMECs induced by Z-VAD-FMK plus OGD/R injury. These results indicate that EPDM may protect HBMECs from cerebral ischemia-reperfusion injury by inhibiting the RIP3/MLKL/PGAM5 pathway and MPTP opening to maintain mitochondrial function, thereby providing a scientific basis for the use of EPDM in the treatment of cerebral ischemia-related diseases.

4.
Chinese Journal of Experimental Traditional Medical Formulae ; (24): 41-48, 2022.
Article in Chinese | WPRIM | ID: wpr-940550

ABSTRACT

ObjectiveTo observe the effect of Danggui Buxuetang on the podocyte injury and receptor-interacting protein kinase 1/receptor-interacting protein kinase3/mixed lineage kinase domain-like protein (RIPK1/RIPK3/MLKL) signaling pathway in diabetic kidney disease (DKD) ratsand to explore its possible mechanism against DKD. MethodEight of the 50 SD rats were randomly classified intoa normal group, and the remaining were fed a high-glucose and high-fat diet for six weeks and then intraperitoneally injected with 0.035 g·kg-1streptozotocin (STZ) for inducing type 2 diabetes. After successful modeling,they were randomized into the model group,high- and low-dose (1.44,0.72 g·kg-1) Danggui Buxuetang groups, and irbesartan (0.017 g·kg-1)group. After 20 weeks of drug intervention, the fasting blood glucose (FBG), kidney index (KI),and urinary microalbumin-to-urine creatinine ratio (UACR)were detected in each group. The pathological changes in renal tissue were observed by hematoxylin-eosin (HE) staining, followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in renal tissue of rats were determined by enzyme-linked immunosorbent assay (ELISA), and the protein expression levels of RIPK1, RIPK3, and MLKL in rat kidney tissue by immunohistochemistry. The apoptosis rate of podocytes was detected by in situ nick end-labeling (TUNEL) assay. The mRNA expression levels of RIPK1, RIPK3, and MLKL in kidney tissue of rats were measured by real-time fluorescence quantitative polymerase chain reaction (Real-time PCR), and the protein expression levels of RIPK, RIPK3, and MLKL and podocyte marker Wilms tumor protein-1 (WT-1) in rat kidney tissue were assayed by Western blot. ResultCompared with the normal group, the model group exhibited elevated FBG, UACR, and KI (P<0.01), glomerular hypertrophy, thickened basement membrane, increased extracellular matrix, mesangial hyperplasia, foot process fusion or loss, enhanced apoptosis in renal tissue, up-regulated TNF-α and IL-6 levels (P<0.01) and RIPK1/RIPK3/MLKL mRNA and protein expression (P<0.01), and down-regulated WT-1 protein expression. Compared with the model group, Danggui Buxuetang high-dose group significantly reduced the levels of FBG, UACR, and KI, improved renal histopathology, podocyte loss, and apoptosis in renal tissue, down-regulated TNF-α and IL-6 levels and RIPK1/RIPK3/MLKL mRNA and protein expression (P<0.05, P<0.01), and up-regulated WT-1 protein expression. ConclusionDanggui Buxuetang alleviates podocyte injury and delays the development of DKD possibly by regulating the RIPK1/RIPK3/MLKL signaling pathway.

5.
Journal of Central South University(Medical Sciences) ; (12): 1289-1298, 2022.
Article in Chinese | WPRIM | ID: wpr-954494

ABSTRACT

The morbidity of inflammatory bowel diseases (IBD) is rising rapidly but no curative therapies to prevent its recurrence. Cell death is crucial to maintaining homeostasis. Necroptosis is a newly identified programmed cell death and its roles played in IBD need to be explored. Necroptosis is mediated by receptor interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL), which resulted in cell swelling, plasma membrane rupture, intracellular content leaking, and eventually cell death as well as the promotion of inflammation. Studies have found that inhibiting necroptosis alleviated IBD in animal models and IBD patients with an increased level of necroptosis in inflammatory tissues, indicating that necroptosis is related to the pathogenesis of IBD. However, due to the complexity in regulation of necroptosis and the involvement of multiple functions of relevant signaling molecules, the specific mechanism remains elusive. Necroptosis may play a vital regulatory role in the pathogenesis of IBD, which provides a new idea and method for further exploring the therapeutic target of IBD.

6.
Acta Academiae Medicinae Sinicae ; (6): 338-347, 2022.
Article in Chinese | WPRIM | ID: wpr-927885

ABSTRACT

Programmed necrosis,a mode of cell death independent of Caspase,is mainly mediated by receptor-interacting protein kinase-1 (RIPK1),receptor-interacting protein kinase-3 (RIPK3),and mixed lineage kinase domain-like protein (MLKL).Studies have demonstrated that programmed necrosis has the dual role of promoting and inhibiting tumor growth and thus we can control the development of tumor by regulating programmed necrosis.The drugs capable of inducing programmed necrosis show potential anti-tumor activity.In addition,inducing programmed necrosis is an effective way to overcome tumor resistance to apoptosis.This paper summarized the mechanisms of programmed necrosis and its relationship with tumors.We focused on the antitumor activity of programmed necrosis inducers including natural products,chemotherapeutic drugs,death receptor ligands,kinase inhibitors,inorganic salts,metal complexes,and metal nanoparticles.These agents will provide new therapeutic candidates for the treatment of tumors,especially the tumors acquiring resistance to apoptosis.


Subject(s)
Humans , Apoptosis , Cell Death , Necrosis/pathology , Neoplasms/drug therapy , Protein Kinases/pharmacology
7.
Journal of Environmental and Occupational Medicine ; (12): 1370-1375, 2021.
Article in Chinese | WPRIM | ID: wpr-960746

ABSTRACT

Background Programmed necrosis is closely related to the occurrence and development of neurodegenerative diseases, but whether lead causes programmed cell necrosis has not been reported. Objective This experiment is designed to probe into the function of programmed necrosis and the effect of its inhibitor on lead-induced microglia (BV2 cell) injury. Methods The BV2 cells at logarithmic growth phase were treated with 0, 1, 5, 10, 25, 50, 100, and 200 μmol·L−1 lead acetate for 12, 24, 36, and 48 h, respectively, and methylthiazolyldiphenyl-tetrazolium bromide (MTT) was used to determine cell viability. After treatment with 0, 25, 50, and 100 μmol·L−1 lead acetate for 24 h, enzyme-linked immunosorbent assay, Western blotting, and flow cytometry were used to determine the expressions of tumor necrosis factor-α (TNF-α), receptor-interacting protein kinase 3 (RIPK3), receptor-interacting protein kinase 1 (RIPK1), and mixed lineage kinase domain-like protein (MLKL) in the cells, and the effect of RIPK1 inhibitor Nec-1 pretreatment on lead-induced BV2 cell injury . Results The BV2 cell viability decreased with higher lead concentration (r12 h=−0.995, r24 h=−0.984, r36 h=−0.983, r48 h=−0.981, all P<0.01) and time extension (only for 5 μmol·L−1 lead acetate, r=−0.994, P<0.01). Compared with the control group, the BV2 cell viability decreased at the same exposure time when the concentration of lead was above 10 μmol·L−1 (P<0.01). Compared with the control group, the expressions of RIPK1 and MLKL were increased in the 25, 50, and 100 μmol·L−1 lead groups (P<0.05 or 0.01), accompanied by an increase in the contents of inflammatory cytokine TNF-α, especially in the 100 μmol·L−1 lead group, the increment was the highest (P<0.01). The expression levels of p-RIPK1 and p-MLKL in BV2 cells were both increased when the concentration of lead acetate was above 50 μmol·L−1 (P<0.01). In addition, pretreatment with Nec-1 increased the cell viability rate and decreased the necrosis and late apoptosis rate of BV2 cells exposed to lead compared with corresponding lead exposure groups (P<0.05). Conclusions Lead can reduce BV2 cell viability, increase necrosis rate, and up-regulate the expressions of RIPK1, RIPK3, amd MLKL, and the phosphorylation levels of RIPK1 and MLKL. The RIPK1 inhibitor Nec-1 has an intervention effect on lead-induced damage in BV2 cells, indicating that programmed necrosis may play a role in lead neurotoxicity.

8.
Chinese Journal of Dermatology ; (12): 302-309, 2019.
Article in Chinese | WPRIM | ID: wpr-745785

ABSTRACT

Objective To evaluate the inductive effect of interferon-γ(IFN-γ) combined with tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) on programmed necrosis of the human immortalized keratinocyte cell line HaCaT,and to explore its mechanisms.Methods In vitro cultured HaCaT cells were divided into several groups:negative control group receiving no treatment,IFN-γ group treated with 50 μg/L IFN-γ,TRAIL group treated with 4 μg/L TRAIL,and cytokine combination group treated with 50 μg/L IFN-γ and 4 μg/L TRAIL or zVAD combination group pretreated with 40 μmo/L zVAD for 1 hour followed by the treatment with 50 μg/L IFN-γand 4 μg/L TRAIL.After 48-hour treatment,the morphology of HaCaT cells were observed under a light microscope,methyl-thiazolyl-tetrazolium assay was performed to evaluate the inhibitory effect of the treatment on the proliferation of HaCaT cells,and double staining flow cytometry to detect the necrosis of HaCaT cells.Meanwhile,real-time fluorescence-based quantitative PCR (qPCR) was conducted to determine the mRNA expression of receptor interaction protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL),Western blot analysis to determine the expression of RIP1,RIP3,MLKL proteins and their phosphorylated forms (pRIP1,pRIP3,pMLKL),immunofluorescent staining to observe the distribution of pRIP3 and pMLKL in HaCaT cells,and the level of reactive oxygen species (ROS) in HaCaT cells in the above groups was detected by the fluorescence probe DCFH-DA.Statistical analysis was carried out with SPSS 22 software by using one-way analysis of variance (ANOVA) for comparing indices among different groups,and least significant difference (LSD)-t test for multiple comparisons.Results After 48-hour treatment,HaCaT cells in the cytokine combination group and zVAD combination group showed necrosis-like morphologic features.Methyl-thiazolyl-tetrazoliumassay revealed significant differences in the survival rate of HaCaT cells among the IFN-γgroup,TRAIL group,cytokine combination group,zVAD combination group and negative control group (73.16% ± 5.71%,81.46% ± 4.68%,72.18% ± 2.93%,69.67% ± 3.24% and 100%,respectively;F =24.34,P < 0.001).The necrosis rate of HaCaT cells was notably higher in the cytokine combination group and zVAD combination group (9.86% ± 1.31%,10.33% ± 2.16%,respectively) than in the negative control group (5.26% ± 0.91%,t =4.61,5.07,respectively,both P < 0.05).qPCR revealed that the mRNA expression of RIP3 and MLKL significantly increased in the cytokine combination group and zVAD combination group compared with the negative control group (tRIP3 =0.99,1.84,tMLKL =1.51,2.17,respectively,all P < 0.05).Western blot analysis suggested that the protein expression of RIP1,RIP3,MLKL,pRIP1,pRIP3 and pMLKL significantly increased in the cytokine combination group compared with the negative control group (all P < 0.05),and the zVAD combination group showed significantly decreased caspase 8 expression and increased expression of the above proteins compared with the cytokine combination group.Fluorescence microscopy showed that enhanced green dot-like or clump-like fluorescent spots (representing pRIP3) could be observed in the cytoplasm,and red fluorescent spots (representing pMLKL) could be seen on the cell membrane in the cytokine combination group.The average fluorescence intensity of ROS was significantly higher in the cytokine combination group than in the negative control group (t =702.00,P < 0.05).Conclusion IFN-γcombined with TRAIL can induce the programmed necrosis of HaCaT cells with increased level of ROS.

9.
Journal of Zhejiang University. Science. B ; (12): 399-413, 2019.
Article in English | WPRIM | ID: wpr-847040

ABSTRACT

Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein (RIP) kinases RIPK1 and RIPK3, as well as the RIPK3 substrate mixed lineage kinase domain-like protein (MLKL). Because of membrane rupture, necroptotic cells release damage-associated molecular patterns (DAMPs) that evoke immune responses. Necroptosis is emerging as an important cellular response in the modulation of cancer initiation, progression, and metastasis. Necroptosis of cancer cells is considered to be an immunogenic cell death capable of activating anti-tumor immunity. Necroptosis also participates in the promotion of myeloid cell-induced adaptive immune suppression and thus contributes to oncogenesis. In addition, necroptosis of endothelial cells and tumor cells is conducive to tumor metastasis. In this review, we summarize the current knowledge of the complex role of necroptosis in cancer and discuss the potential of targeting necroptosis components for cancer therapies.

10.
Journal of Zhejiang University. Science. B ; (12): 399-413, 2019.
Article in English | WPRIM | ID: wpr-776722

ABSTRACT

Necroptosis is a tightly regulated form of necrosis that requires the activation of receptor-interacting protein (RIP) kinases RIPK1 and RIPK3, as well as the RIPK3 substrate mixed lineage kinase domain-like protein (MLKL). Because of membrane rupture, necroptotic cells release damage-associated molecular patterns (DAMPs) that evoke immune responses. Necroptosis is emerging as an important cellular response in the modulation of cancer initiation, progression, and metastasis. Necroptosis of cancer cells is considered to be an immunogenic cell death capable of activating anti-tumor immunity. Necroptosis also participates in the promotion of myeloid cell-induced adaptive immune suppression and thus contributes to oncogenesis. In addition, necroptosis of endothelial cells and tumor cells is conducive to tumor metastasis. In this review, we summarize the current knowledge of the complex role of necroptosis in cancer and discuss the potential of targeting necroptosis components for cancer therapies.

11.
Academic Journal of Second Military Medical University ; (12): 1122-1127, 2018.
Article in Chinese | WPRIM | ID: wpr-838327

ABSTRACT

Objective To investigate the expression of mixed lineage kinase domain-like protein (MLKL) in uterus during early pregnancy and decidua in mice. Methods Different mouse models including early pregnancy model, artificially induced decidualization model and hormone and/or progesterone treatment of uterine model were constructed; human endometrial stromal cells were cultured in vitro and were induced for decidualization by treating with estradiol-17β, medroxyprogesterone acetate and dibutyryl cyclic adenosine monophosphate. The expression of MLKL mRNA and protein in the uterus of early pregnancy, decidual uterus, and hormone-treated uterus in mice were analyzed by real-time fluorescent quantitative PCR, in situ hybridization and Western blotting. The expression of MLKL mRNA in human decidual cells induced in vitro was detected by real-time fluorescent quantitative PCR. Results (1) In the uterus during early pregnancy in mice, the expression of MLKL mRNA and protein in uterine epithelium on the 1st to 4th day of pregnancy (day 1 was day of vaginal sperm) was low and irregular. It was expressed in the uterine epithelium and surrounding decidual cells on the 5th day of pregnacy, and was mainly expressed in the decidua from the 6th to 8th day of pregnancy. After the implantation, the expression of MLKL mRNA and protein was day-by-day increased and reached the highest on the 7th day of pregnancy, with a slight decrease on the 8th day. (2) In the uterus of mice with artificially induced decidualization, MLKL mRNA was expressed in the entire decidual region with high level; while there was no significant expression in the uterus of the control mice. The expression of MLKL protein was consistent with the expression of MLKL mRNA. The expression of MLKL mRNA in human decidual cells induced in vitro was significantly higher than that in the control group (P0.05). (3) The expression of MLKL mRNA and protein in progesterone-treated uterus was significantly increased compared with the control group (P0.05). Conclusion MLKL regulated by steroid hormone progesterone is involved in embryo implantation and decidualization of mammals.

12.
Chinese Journal of Behavioral Medicine and Brain Science ; (12): 917-921, 2017.
Article in Chinese | WPRIM | ID: wpr-666912

ABSTRACT

Objective To explore the effect and mechanism of necroptosis related proteins in middle cerebral artery occlusion (MCAO) induced brain ischemia/reperfusion injury in mice.Methods C57BL/6 mice were used to establish the brain ischemia/reperfusion injury model induced by MCAO.MCAO mice were treated with z-VAD.fmk (zVAD,1.1 g/kg),GSK'872 (0.7 g/kg) and combined intervention of zVAD and GSK'872,and neurological defect was evaluated by mNSS while brain infarct volume was measured by TTC staining.Western blot and immunofluorescence assay were used to detect protein expression and location of RIP1,RIP3 and MLKL,respectively.Results Neurological defect and brain infarction were caused by MCAO.Compared with MCAO group,zVAD,GSK'872 and the combined intervention alleviated neurological defect and reduced brain infarct volume significantly (P<0.05 or P<0.01).The protein levels of RIP3 and RIP1 MLKL were increased in mice of MCAO group,while GSK'872 and the combined intervention obviously downregulated the aforementioned protein expression [RIP1 (GSK'872:0.64± 0.02 vs MCAO:1.28±0.02,P<0.01);RIP3 (GSK'872:1.08±0.02 vs MCAO:1.45±0.02,P<0.01);MLKL (GSK'872:0.54±0.01 vs MCAO:1.00±0.01,P<0.01)].However,zVAD only slightly reduced protein expression of MLKL (P<0.05) but didn't change the protein expression of RIP1 and RIP3 (P>0.05).Conclusion RIP1,RIP3 and MLKL are involved in the execution of necroptosis and contribute to the pathological progress of brain ischemia/reperfusion injury.

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