The mechanism of action of mitochondrial dysfunction in the development of non-alcoholic fatty liver disease / 临床肝胆病杂志

Nonalcoholic fatty liver disease （NAFLD） has gradually become the main reason affecting human liver health， and many factors are involved in the development and progression of NAFLD. Mitochondria， as the “energy factory” of cells， plays an important role in maintaining normal physiological functions. Studies have shown that hepatic mitochondrial dysfunction promotes the development and progression of NAFLD. This article briefly introduces the latest research advances in the basic characteristics and physiological function of liver mitochondria and reviews new research findings in the association of mitochondrial dysfunction with obesity， simple fatty liver disease， and nonalcoholic steatohepatitis， in order to provide new ideas for the research on targeted mitochondrial therapy for NAFLD.

Prevention and Treatment of Alzheimer's Disease by Traditional Chinese Medicine via Regulating ROS： A Review / 中国实验方剂学杂志

The pathological mechanism of Alzheimer's disease （AD） is complex， and there are many hypotheses. The mainstream theory is the amyloid-beta protein （Aβ） and Tau protein phosphorylation. Oxidative stress （OS） is a bridge between other hypotheses and mechanisms and plays a key role in many hypotheses. Therefore， the treatment of OS in AD （ADOS） is beneficial in alleviating disease progression. Reactive oxygen species （ROS） is a kind of antioxidant and a kind of oxidation products， with Aβ and Tau protein interactions， activating microglia and astrocytes， triggering inflammation and mitochondrial dysfunction， leading to the deterioration of the environment in the brain， and accelerating the development of disease. ROS， as a signal messenger inducing OS， is widely involved in the progression of AD and may be a new target for the progression of AD. Traditional Chinese medicine （TCM） monomers and compounds play an increasingly important role in the prevention and treatment of AD. Recent studies have found that the effective prevention and treatment of AD by TCM is closely related to the regulation of ROS. There are many studies on the mechanism of TCM in the treatment of AD via regulating ROS， but there is a lack of systematic review. By analyzing and summarizing the literature in China and abroad in recent years， this paper reviewed the generation and physiology of ROS， the mechanism of action of AD， and the prevention of AD by TCM via regulating ROS through relevant ways， so as to provide references for the research on the regulation of ROS by TCM and provide new targets and new methods for the prevention and treatment of AD.

Role of endothelial nitric oxide synthase in exercise preconditioning-induced improvement of myocardial ischemia-reperfusion injury / 中国组织工程研究

BACKGROUND:Exercise is an effective strategy to prevent and treat various cardiovascular diseases and protect the heart from ischemia-reperfusion injury.Its mechanism of action needs to be studied in depth. OBJECTIVE:To observe the effect of aerobic exercise preconditioning on myocardial ischemia-reperfusion injury and to explore the effect of endothelial nitric oxide synthase(eNOS)activation(including coupling and phosphorylation). METHODS:Eighty adult Wistar rats were randomly divided into sedentary(n=40)and exercise(n=40)groups.The rats in the exercise group were subjected to aerobic exercise for 8 weeks while those in the sedentary group were quietly fed and caged.After 8 weeks of intervention,three experiments were performed.(1)Experiment 1:After the last training,cardiac function,cardiac nitric oxide metabolite content and cardiac eNOS,phosphorylated eNOS-S1177,eNOS dimer and eNOS monomer protein expression levels were detected.(2)Experiment 2:Rats were divided into sedentary control group,exercise control group,sedentary+eNOS inhibitor group,exercise+eNOS inhibitor group,all of which were subjected to an in vitro myocardial ischemia-reperfusion injury experiment.eNOS inhibitor was continuously infused into the sedentary+eNOS inhibitor group and exercise+eNOS inhibitor group 10 minutes before reperfusion,and cardiac function and myocardial infarction area were detected 3 hours after reperfusion.(3)Experiment 3:Rats were divided into sedentary control group,exercise control group,sedentary+eNOS coupler group and exercise+eNOS coupler group,all of which were subjected to an in vitro myocardial ischemia-reperfusion injury experiment.The rats in the sedentary+eNOS coupler group and exercise+eNOS coupler group were treated with eNOS coupler.Myocardial infarct area,cardiac nitric oxide metabolite content,cardiac protein expression of eNOS,phosphorylated eNOS-S1177,eNOS dimer,eNOS monomer and 3-nitrotyrosine were detected 3 hours after reperfusion.The phosphorylated eNOS-S1177/eNOS ratio reflected the phosphorylated/dephosphorylated level of eNOS and eNOS dimer/monomer ratio reflected eNOS coupling/uncoupling level. RESULTS AND CONCLUSION:Experiment 1:Compared with the sedentary group,the exercise group had increased cardiac output and left ventricular ejection fraction(P<0.05),increased nitrite and S-nitrosothiol contents(P<0.05),upregulated phosphorylated eNOS-S1177,eNOS protein expression and phosphorylated eNOS-S1177/eNOS ratio(P<0.05),eNOS dimer protein expression and eNOS dimer/monomer ratios were elevated(P<0.05).Experiment 2:Compared with the sedentary control group,left ventricular development pressure increased(P<0.05)and myocardial infarct area decreased(P<0.05)in the exercise control group.Compared with the exercise control group,left ventricular development pressure decreased(P<0.05)and myocardial infarct area increased(P<0.05)in the exercise+eNOS inhibitor group.Experiment 3:Compared with the sedentary control group,the exercise control group had increased left ventricular developmental pressure(P<0.05),decreased myocardial infarct area(P<0.05),decreased phosphorylated eNOS-S1177/eNOS ratio(P<0.05),decreased eNOS dimer/monomer ratio(P<0.05),increased S-nitrosothiol content(P<0.05),and decreased 3-nitrotyrosine protein expression(P<0.05).Compared with the exercise control group,the exercise+eNOS coupler group had decreased left ventricular developmental pressure(P<0.05),increased myocardial infarct area(P<0.05),increased phosphorylated eNOS-S1177/eNOS ratio(P<0.05),increased eNOS dimer/monomer ratio(P<0.05),and elevated 3-nitro tyrosine protein expression(P<0.05).To conclude,aerobic exercise preconditioning could induce cardioprotection,which is related to uncoupling and dephosphorylation of eNOS during cardiac ischemia-reperfusion,thereby inhibiting the excessive production of nitric oxide and reducing nitro-oxidative stress.

Abnormal modification of alpha-synuclein and its mechanism in Parkinson's disease / 中国组织工程研究

BACKGROUND:The formation of Lewy bodies due to abnormal α-synuclein aggregation is a characteristic pathological change in Parkinson's disease.In recent years,several studies have revealed that the formation of α-synuclein aggregates is closely related to its post-translational modifications.The modification of α-synuclein such as phosphorylation,nitration,acetylation,and ubiquitination has attracted extensive attention in the pathogenesis and progression of Parkinson's disease. OBJECTIVE:To review the research progress in the effect of modification types and sites of α-synuclein on the characteristic pathological formation and progression of Parkinson's disease. METHODS:PubMed and CNKI databases were searched by the first author with the key words of"α-synuclein,Parkinson's disease,phosphorylation,acetylation,ubiquitination,nitration"in English and Chinese respectively to collect and sort out the literature related to abnormal modification of α-synuclein in recent years.Finally,61 articles were included for further review. RESULTS AND CONCLUSION:Abnormal modification of α-synuclein is closely related to its protein structure and its positive and negative charges.Its amino terminus is positively charged and prone to ubiquitination and acetylation modifications.The central hydrophobic region is prone to forming β-pleated sheet due to its hydrophobic property.The carboxyl terminus is negatively charged,which is the main phosphorylation modification region.Phosphorylation modification sites promote phosphorylation modification and are closely related to α-synuclein aggregation,while protein kinases can target the activation of translational modifications,which may help to promote or inhibit aggregate formation.The degradation pathway of α-synuclein mainly plays a role in removing pathological proteins.Various kinase catalysts contribute to impaired protein ubiquitination modifications that lead to abnormal protein accumulation,thereby exacerbating neurodegeneration.The amino-terminal acetylation of α-synuclein improves the shuttle ability of the protein to the cell membrane and slows down the protein aggregation,which may be the protection target of nerve cells.However,the acetylation modification of the mutant protein produces the opposite effect.The protein nitration modification is mainly related to oxidative stress.The aggregation tendency of the protein modified by nitration is enhanced under the action of reactive oxygen species.Different post-translational modifications have different effects.Therefore,elucidating the main mechanisms of their post-translational modifications and inhibiting the post-translational modifications that contribute to protein aggregation may provide a reference for new targets for early diagnosis and treatment of Parkinson's disease.

Protective effect of C2 ceramide on dopaminergic neurons in a mouse model of Parkinson's disease / 中国组织工程研究

BACKGROUND:C2 ceramide reduces the formation of Alpha-Synuclein(α-Syn)oligomers as the protein phosphatase 2A agonist,which has an important regulatory effect on cell aging in the central nervous system. OBJECTIVE:To investigate the protective mechanism of C2 ceramide on dopaminergic neurons. METHODS:Twenty-five C57BL/6 mice were randomly divided into control group,model group,C2 ceramide low-,medium-and high-dose groups(n=5 per group).Except for the control group,a mouse model of Parkinson's disease was established by injecting mutant A53T α-Syn oligomers into the left striatum in the other groups.On the 30th day after the striatal injection,three C2 ceramide groups were intragastrically administered with C2 ceramide(1,5,10 μg/g)dissolved in saline at one time,while the control and model groups were administered with the same amount of saline within 30-90 days after modeling,for a total of 60 days.Behavioral changes in each group of mice were observed during this period.On the 90th day after striatal injection,mouse brain tissue was extracted by perfusion under anesthesia,and the changes of dopaminergic neurons in the midbrain substantia nigra were analyzed by immunohistochemical staining.The levels of α-Syn oligomerization and phosphorylation in the midbrain of mice were detected by ELISA,and the changes of enzyme activities related to α-Syn phosphorylation were analyzed. RESULTS AND CONCLUSION:C2 ceramide had an ameliorating effect on Parkinson's disease-like dyskinesia in mice caused by the striatal injection of mutant A53T α-Syn oligomers.High-dose C2 ceramide showed better effects on dyskinesia in mice with Parkinson's disease(P<0.01).The mutant A53T α-Syn oligomers significantly reduced the number of dopaminergic neurons in the substantia nigra of mice(P<0.01),while the number of dopaminergic neurons in the substantia nigra increased significantly in the C2 ceramide high-dose group(P<0.01).The levels of α-Syn oligomers and phosphorylated α-Syn in the brain were significantly reduced in the C2 ceramide high-dose group compared with the model group(P<0.01),while the level of ceramide was increased(P<0.05)and the activity of protein phosphatase 2A was significantly upregulated(P<0.01).To conclude,C2 ceramide can attenuate the neurotoxic effects induced by oligomerized α-Syn by the phosphorylation modification environment of α-Syn in mouse midbrain tissue and protect against the reduction in the number of nigrostriatal dopaminergic neurons in mice,thereby reducing the degree of dyskinesia in Parkinson's disease.

Shakuyakukanzoto Relieves Ulcerative Colitis in Mice by Regulating The Expression of NDUFS1 and Inhibiting The Polarization of Macrophages to M1 / 生物化学与生物物理进展

ObjectiveThis study aims to explore and elucidate the possible mechanism of action of Shakuyakukanzoto (SKT) in improving ulcerative colitis (UC) in mice through regulating energy metabolism and polarization of macrophages. MethodsThe mouse UC model was constructed by administering 3% dextran sulfate sodium salt (DSS), and the mice were treated with SKT intragastrically. In addition, single-cell sequencing and enrichment of metabolic pathways against two datasets, GSE21157 and GSE210415, were conducted first. Second, the extraction and metabolomics of peritoneal macrophages from UC mice were verified. Then, the pathway of differentially abundant metabolite enrichment and the correlation of UC risk were analyzed depending on univariate Mendelian randomization of two samples weighted by standard inverse variance. Finally, the results were verified by qRT-PCR, Western blot, and flow cytometry. ResultsAccording to the HE staining results, SKT can significantly alleviate colon damage caused by DSS. Macrophages, NK cells, T cells, and more than 10 different types of cells, based on single-cell sequencing analysis, are detected in the intestinal wall. In the disease group, we can conclude that the activity of 49 macrophage metabolic pathways, mainly involved in energy metabolism, is significantly upregulated through a comparison of the two datasets. In energy metabolomics, 10 and 18 types of metabolites accompanied by significantly upregulated and downregulated differential expression were identified in the treatment group and the model group, as well as the model group and the blank group, respectively. Meanwhile, these differentially expressed metabolites present an obvious correlation with glycolysis and oxidative phosphorylation. Moreover, it can be inferred that glycolysis and the oxidative phosphorylation-related gene NDUFS1 (OR: 0.56, 95% CI: 0.48-0.98, P=0.000 068) are associated with a reduced risk of UC based on the univariate Mendelian randomization of two samples weighted based on standard inverse variance. By analyzing the difference in transcription levels between the two datasets, the transcription level of NDUFS1 in UC was decreased compared with that in the normal group. The results of qRT-PCR, Western blot, and flow cytometry indicate that SKT can promote the expression of the oxidative phosphorylation protein NDUFS1 in macrophages and inhibit the M1-type polarization of macrophages. Furthermore, knockdown/overexpression of NDUFS1 can affect the effect of SKT on M1-type polarization of macrophages. ConclusionBased on the results of this study, SKT inhibits macrophage polarization toward the M1 phenotype by regulating the level of the oxidatively phosphorylated protein NDUFS1 in macrophages; hence, UC is also relieved in mice. These conclusions not only reveal the therapeutic mechanism of SKT for UC but also provide a new theoretical basis for clinical application.

Effect of USP9X on Akt phosphorylation and platelet function / 中国输血杂志

【Objective】 To explore the expression of USP9X in platelets and its effect on platelet function. 【Methods】 The expression of USP9X in human and mouse was evaluated by PCR and Western blot. Platelets from young and old mice were separated and prepared, and the expression of USP9X was detected. USP9X inhibitos were used to assess the regulation of USP9X in platelet function, including aggregation, ATP release and spreading. Platelet lysates were collected in different time points to evaluate the change of phosphorylation of Akt in USP9X inhibitors treated platelets. 【Results】 Both human and mouse platelets expressed USP9X. Compared to the young mice, the old mice showed significantly enhanced expression of USP9X(P<0.05). To assess the effect of USP9X on platelet function, USP9X inhibitor was used to pre-incubate platelets for 30 min and platelet function were examined later. Results showed that USP9X inhibitor significantly decreased platelet activation including aggregation, ATP release and spreading(P<0.05). Compared to the control group, the inhibitor treated group showed a significant decrease in the spreading area after 45 minutes. The Western blot results showed a significant decrease in Akt phosphorylation levels of platelets in the USP9X inhibitor treated group. 【Conclusion】 Both human and mouse platelet express USP9X, and inhibition of USP9X decreased platelet function including aggregation, ATP release and spreading. USP9X can also influence the phosphorylation of Akt. The inhibitor of USP9X may become a potential therapeutic target for thrombosis intervention.

Effects of Lactobacillus Rhamnosus GG on Activated Microglia and Tau Phosphorylation in the Hippocampus of Aged Mice Induced by Anesthesia and Surgery / 中山大学学报(医学科学版)

ObjectiveTo investigate the effects of Lactobacillus rhamnosus GG （LGG）on microglia and Tau phosphorylation in the hippocampus of aged mice induced by anesthesia and surgery. MethodsA total of thirty 18-month-old C57BL/6J mice were randomly divided into three groups： control group， anesthesia surgery group， and anesthesia surgery + LGG group （10 mice/group）. The aged mice were oral administered by NS or LGG 109 CFU 150 μL once a day for 20 days. Then anesthesia surgery group and anesthesia surgery +LGG group received anesthesia with isoflurane and exploratory laparotomy. The activation status of microglia in the hippocampus was detected by immunofluorescence staining 12 hours after surgery. IL-6 concentration changes was detected by ELISA. The expression changes of Tau protein phosphorylation site （Tau-pS202/pT205） and total Tau protein was detected by western blot. ResultsThe microglia in the hippocampus of the control group were in a resting state， and the concentration of inflammatory factor IL-6 was （82.08 ± 12.07） pg/mL in control group. Compared to the control group， the anesthesia surgery group showed microglial cell Microglia were activated， the concentration of inflammatory factors IL-6 increased significantly to （123.7±5.72） pg/mL （P=0.000）， and the expression of phosphorylated Tau-pS202/pT205 increased the hippocampus （P=0.002）. Compared to the anesthesia surgery group， the activated microglia were inhibited， the concentration of IL-6 decreased to （96.68±9.59） pg/mL （P=0.008）， and the expression of phosphorylated Tau-pS202/pT205 reduced significantly in the AS+LGG group （P=0.002）. While there were no significant changes in total Tau protein among 3 groups. ConclusionPreoperative administration of probiotic LGG can alleviate the activation of microglia， increased secretion of inflammatory factors， and increased Tau protein phosphorylation levels in the hippocampus of elderly mice caused by anesthesia surgery.

Role of post-translational modification of basic leucine zipper transcription factors in response to abiotic stresses in plants / 生物工程学报

Abiotic stresses substantially affect the growth and development of plants. Plants have evolved multiple strategies to cope with the environmental stresses, among which transcription factors play an important role in regulating the tolerance to abiotic stresses. Basic leucine zipper transcription factors (bZIP) are one of the largest gene families. The stability and activity of bZIP transcription factors could be regulated by different post-translational modifications (PTMs) in response to various intracellular or extracellular stresses. This paper introduces the structural feature and classification of bZIP transcription factors, followed by summarizing the PTMs of bZIP transcription factors, such as phosphorylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification, in response to abiotic stresses. In addition, future perspectives were prospected, which may facilitate cultivating excellent stress-resistant crop varieties by regulating the PTMs of bZIP transcription factors.

Alterations of serum biochemical parameters and tyrosine phosphorylation in kidney and liver of chronic stress-induced rats / Alterações dos parâmetros bioquímicos séricos e fosforilação da tirosina em rim e fígado de ratos induzidos por estresse crônico

Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male Sprague-Dawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.

O estresse crônico (SC) pode contribuir para a disfunção em vários órgãos, incluindo fígado e rim. Este estudo foi realizado para investigar as alterações na bioquímica sérica, estrutura histológica, bem como na localização de proteínas tirosina fosforiladas (TyrPho) e proteína de choque térmico 70 (Hsp-70) em tecidos hepáticos e renais de ratos CS induzidas por dois estressores (restrito e natação forçada) por 60 dias consecutivos. Amostras de sangue, fígado e rim foram coletadas de ratos Sprague-Dawley machos adultos em cada grupo. Nossos resultados mostraram que os parâmetros bioquímicos séricos, incluindo corticosterona, glicemia, nitrogênio ureico, creatinina, colesterol, triglicerídeos, HDL-C, LDL-C, ALT, AST, fosfatase alcalina no grupo CS foram significativamente diferentes do grupo normal em ambos os fígados e tecidos renais. Embora a estrutura histológica não tenha sido alterada, a expressão de TyrPho aumentou significativamente no lisado hepático, mas diminuiu significativamente no rim. A expressão de Hsp-70 no fígado aumentou, enquanto que no rim diminuiu. Em conclusão, a CS pode induzir alterações nas funções hepáticas e renais.

Alterations of serum biochemical parameters and tyrosine phosphorylation in kidney and liver of chronic stress-induced rats

Abstract Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male SpragueDawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.

Resumo O estresse crônico (SC) pode contribuir para a disfunção em vários órgãos, incluindo fígado e rim. Este estudo foi realizado para investigar as alterações na bioquímica sérica, estrutura histológica, bem como na localização de proteínas tirosina fosforiladas (TyrPho) e proteína de choque térmico 70 (Hsp-70) em tecidos hepáticos e renais de ratos CS induzidas por dois estressores (restrito e natação forçada) por 60 dias consecutivos. Amostras de sangue, fígado e rim foram coletadas de ratos Sprague-Dawley machos adultos em cada grupo. Nossos resultados mostraram que os parâmetros bioquímicos séricos, incluindo corticosterona, glicemia, nitrogênio ureico, creatinina, colesterol, triglicerídeos, HDL-C, LDL-C, ALT, AST, fosfatase alcalina no grupo CS foram significativamente diferentes do grupo normal em ambos os fígados e tecidos renais. Embora a estrutura histológica não tenha sido alterada, a expressão de TyrPho aumentou significativamente no lisado hepático, mas diminuiu significativamente no rim. A expressão de Hsp-70 no fígado aumentou, enquanto que no rim diminuiu. Em conclusão, a CS pode induzir alterações nas funções hepáticas e renais.

Embryo development is impaired by sperm mitochondrial-derived ROS

BACKGROUND: Basal energetic metabolism in sperm, particularly oxidative phosphorylation, is known to condition not only their oocyte fertilising ability, but also the subsequent embryo development. While the molecular pathways underlying these events still need to be elucidated, reactive oxygen species (ROS) could have a relevant role. We, therefore, aimed to describe the mechanisms through which mitochondrial activity can influence the first stages of embryo development. RESULTS: We first show that embryo development is tightly influenced by both intracellular ROS and mitochondrial activity. In addition, we depict that the inhibition of mitochondrial activity dramatically decreases intracellular ROS levels. Finally, we also demonstrate that the inhibition of mitochondrial respiration positively influences sperm DNA integrity, most likely because of the depletion of intracellular ROS formation. CONCLUSION: Collectively, the data presented in this work reveals that impairment of early embryo development may result from the accumulation of sperm DNA damage caused by mitochondrial-derived ROS.

Phosphoproteomic analysis of human umbilical venous endothelial cells with DENV-2 infection / 南方医科大学学报

OBJECTIVE@#To analyze the differentially phosphorylated proteins in DENV-2-infected human umbilical venous endothelial cells (HUVECs) and explore the possible pathogenic mechanism of DENV-2 infection.@*METHODS@#The total proteins were extracted from DENV-2-infected HUVECs and blank control HUVEC using SDT lysis method. The phosphorylated proteins were qualitatively and quantitatively analyzed using tandem mass spectrometry (TMT). The identified differentially phosphorylated proteins were analyzed by bioinformatics analyses such as subcellular localization analysis, GO enrichment analysis, KEGG pathway analysis and protein-protein interaction (PPI) analysis. Western blotting was used to detect the expressions of phosphorylated Jun, map2k2 and AKT1 proteins in DENV-2-infected HUVECs.@*RESULTS@#A total of 2918 modified peptides on 1385 different proteins were detected, and among them 1346 were significantly upregulated (FC > 1.2, P < 0.05) and 1572 were significantly downregulated (FC < 0.83, P < 0.05). A total of 49 phosphorylated conserved motifs were obtained by amino acid conservative motif analysis. The most abundant differentially phosphorylated peptides in protein domain analysis included RNA recognition motif, protein kinase domain and PH domain. Subcellular localization analysis showed that the differentially modified peptides were mainly localized in the nucleus and cytoplasm. GO enrichment and KEGG pathway analysis showed that the differential peptides were mainly enriched in the regulation of stimulation response, biosynthesis of small molecules containing nuclear bases, and migration of phagosomes and leukocytes across the endothelium. PPI and KEGG joint analysis showed that the up-regulated and down-regulated differentially phosphorylated proteins were enriched in 15 pathways. In DENV-2-infected HUVECs, Western blotting detected differential expressions of phosphorylated proteins related with the autophagy pathway, namely JUN, MAP2K2 and AKT1, and among them p-JUN was significantly down-regulated and p-AKT1 and p-MAP2K2 were significantly upregulated (P < 0.01).@*CONCLUSION@#DENV-2 infected HUVECs show numerous differentially expressed proteins. The downregulation of p-JUN and upregulation of p-MAP2K2 and p-AKT1 suggest their potential roles in regulating autophagy, which is probably involved in the mechanism of DENV-2 infection.

Mechanisms of PiT2-loop7 Missense Mutations Induced Pi Dyshomeostasis / 神经科学通报·英文版

PiT2 is an inorganic phosphate (Pi) transporter whose mutations are linked to primary familial brain calcification (PFBC). PiT2 mainly consists of two ProDom (PD) domains and a large intracellular loop region (loop7). The PD domains are crucial for the Pi transport, but the role of PiT2-loop7 remains unclear. In PFBC patients, mutations in PiT2-loop7 are mainly nonsense or frameshift mutations that probably cause PFBC due to C-PD1131 deletion. To date, six missense mutations have been identified in PiT2-loop7; however, the mechanisms by which these mutations cause PFBC are poorly understood. Here, we found that the p.T390A and p.S434W mutations in PiT2-loop7 decreased the Pi transport activity and cell surface levels of PiT2. Furthermore, we showed that these two mutations attenuated its membrane localization by affecting adenosine monophosphate-activated protein kinase (AMPK)- or protein kinase B (AKT)-mediated PiT2 phosphorylation. In contrast, the p.S121C and p.S601W mutations in the PD domains did not affect PiT2 phosphorylation but rather impaired its substrate-binding abilities. These results suggested that missense mutations in PiT2-loop7 can cause Pi dyshomeostasis by affecting the phosphorylation-regulated cell-surface localization of PiT2. This study helps understand the pathogenesis of PFBC caused by PiT2-loop7 missense mutations and indicates that increasing the phosphorylation levels of PiT2-loop7 could be a promising strategy for developing PFBC therapies.

Berberine targets the electron transport chain complex I and reveals the landscape of OXPHOS dependency in acute myeloid leukemia with IDH1 mutation / 中国天然药物

Metabolic reprogramming, a newly recognized trait of tumor biology, is an intensively studied prospect for oncology medicines. For numerous tumors and cancer cell subpopulations, oxidative phosphorylation (OXPHOS) is essential for their biosynthetic and bioenergetic functions. Cancer cells with mutations in isocitrate dehydrogenase 1 (IDH1) exhibit differentiation arrest, epigenetic and transcriptional reprogramming, and sensitivity to mitochondrial OXPHOS inhibitors. In this study, we report that berberine, which is widely used in China to treat intestinal infections, acted solely at the mitochondrial electron transport chain (ETC) complex I, and that its association with IDH1 mutant inhibitor (IDH1mi) AG-120 decreased mitochondrial activity and enhanced antileukemic effect in vitro andin vivo. Our study gives a scientific rationale for the therapy of IDH1 mutant acute myeloid leukemia (AML) patients using combinatory mitochondrial targeted medicines, particularly those who are resistant to or relapsing from IDH1mi.

SIRT1 activation synergizes with FXR agonism in hepatoprotection via governing nucleocytoplasmic shuttling and degradation of FXR

Farnesoid X receptor (FXR) is widely accepted as a promising target for various liver diseases; however, panels of ligands in drug development show limited clinical benefits, without a clear mechanism. Here, we reveal that acetylation initiates and orchestrates FXR nucleocytoplasmic shuttling and then enhances degradation by the cytosolic E3 ligase CHIP under conditions of liver injury, which represents the major culprit that limits the clinical benefits of FXR agonists against liver diseases. Upon inflammatory and apoptotic stimulation, enhanced FXR acetylation at K217, closed to the nuclear location signal, blocks its recognition by importin KPNA3, thereby preventing its nuclear import. Concomitantly, reduced phosphorylation at T442 within the nuclear export signals promotes its recognition by exportin CRM1, and thereby facilitating FXR export to the cytosol. Acetylation governs nucleocytoplasmic shuttling of FXR, resulting in enhanced cytosolic retention of FXR that is amenable to degradation by CHIP. SIRT1 activators reduce FXR acetylation and prevent its cytosolic degradation. More importantly, SIRT1 activators synergize with FXR agonists in combating acute and chronic liver injuries. In conclusion, these findings innovate a promising strategy to develop therapeutics against liver diseases by combining SIRT1 activators and FXR agonists.

Targeting metabolic vulnerability in mitochondria conquers MEK inhibitor resistance in KRAS-mutant lung cancer

MEK is a canonical effector of mutant KRAS; however, MEK inhibitors fail to yield satisfactory clinical outcomes in KRAS-mutant cancers. Here, we identified mitochondrial oxidative phosphorylation (OXPHOS) induction as a profound metabolic alteration to confer KRAS-mutant non-small cell lung cancer (NSCLC) resistance to the clinical MEK inhibitor trametinib. Metabolic flux analysis demonstrated that pyruvate metabolism and fatty acid oxidation were markedly enhanced and coordinately powered the OXPHOS system in resistant cells after trametinib treatment, satisfying their energy demand and protecting them from apoptosis. As molecular events in this process, the pyruvate dehydrogenase complex (PDHc) and carnitine palmitoyl transferase IA (CPTIA), two rate-limiting enzymes that control the metabolic flux of pyruvate and palmitic acid to mitochondrial respiration were activated through phosphorylation and transcriptional regulation. Importantly, the co-administration of trametinib and IACS-010759, a clinical mitochondrial complex I inhibitor that blocks OXPHOS, significantly impeded tumor growth and prolonged mouse survival. Overall, our findings reveal that MEK inhibitor therapy creates a metabolic vulnerability in the mitochondria and further develop an effective combinatorial strategy to circumvent MEK inhibitors resistance in KRAS-driven NSCLC.

HBXIP blocks myosin-IIA assembly by phosphorylating and interacting with NMHC-IIA in breast cancer metastasis

Tumor metastasis depends on the dynamic balance of the actomyosin cytoskeleton. As a key component of actomyosin filaments, non-muscle myosin-IIA disassembly contributes to tumor cell spreading and migration. However, its regulatory mechanism in tumor migration and invasion is poorly understood. Here, we found that oncoprotein hepatitis B X-interacting protein (HBXIP) blocked the myosin-IIA assemble state promoting breast cancer cell migration. Mechanistically, mass spectrometry analysis, co-immunoprecipitation assay and GST-pull down assay proved that HBXIP directly interacted with the assembly-competent domain (ACD) of non-muscle heavy chain myosin-IIA (NMHC-IIA). The interaction was enhanced by NMHC-IIA S1916 phosphorylation via HBXIP-recruited protein kinase PKCβII. Moreover, HBXIP induced the transcription of PRKCB, encoding PKCβII, by coactivating Sp1, and triggered PKCβII kinase activity. Interestingly, RNA sequencing and mouse metastasis model indicated that the anti-hyperlipidemic drug bezafibrate (BZF) suppressed breast cancer metastasis via inhibiting PKCβII-mediated NMHC-IIA phosphorylation in vitro and in vivo. We reveal a novel mechanism by which HBXIP promotes myosin-IIA disassembly via interacting and phosphorylating NMHC-IIA, and BZF can serve as an effective anti-metastatic drug in breast cancer.

Enhanced endoplasmic reticulum RyR1 receptor phosphorylation leads to diaphragmatic dysfunction in septic rats / 南方医科大学学报

OBJECTIVE@#To explore the role of endoplasmic reticulum ryanodine receptor 1 (RyR1) expression and phosphorylation in sepsis- induced diaphragm dysfunction.@*METHODS@#Thirty SPF male SD rats were randomized equally into 5 groups, including a sham-operated group, 3 sepsis model groups observed at 6, 12, or 24 h following cecal ligation and perforation (CLP; CLP-6h, CLP-12h, and CLP-24h groups, respectively), and a CLP-24h group with a single intraperitoneal injection of KN- 93 immediately after the operation (CLP-24h+KN-93 group). At the indicated time points, diaphragm samples were collected for measurement of compound muscle action potential (CMAP), fatigue index of the isolated diaphragm and fitted frequencycontraction curves. The protein expression levels of CaMK Ⅱ, RyR1 and P-RyR1 in the diaphragm were detected using Western blotting.@*RESULTS@#In the rat models of sepsis, the amplitude of diaphragm CMAP decreased and its duration increased with time following CLP, and the changes were the most obvious at 24 h and significantly attenuated by KN-93 treatment (P < 0.05). The diaphragm fatigue index increased progressively following CLP (P < 0.05) irrespective of KN- 93 treatment (P>0.05). The frequency-contraction curve of the diaphragm muscle decreased progressively following CLP, and was significantly lower in CLP-24 h group than in CLP-24 h+KN-93 group (P < 0.05). Compared with that in the sham-operated group, RyR1 expression level in the diaphragm was significantly lowered at 24 h (P < 0.05) but not at 6 or 12 following CLP, irrespective of KN-93 treatment; The expression level of P-RyR1 increased gradually with time after CLP, and was significantly lowered by KN-93 treatment at 24 h following CLP (P < 0.05). The expression level of CaMKⅡ increased significantly at 24 h following CLP, and was obviously lowered by KN-93 treatment (P < 0.05).@*CONCLUSION@#Sepsis causes diaphragmatic dysfunction by enhancing CaMK Ⅱ expression and RyR1 receptor phosphorylation in the endoplasmic reticulum of the diaphragm.

Research progress on AMPARs involved in regulating orofacial pain / 口腔疾病防治

@#The incidence of orofacial pain is high, and its pathological mechanism is complex. Currently, there is a lack of long-lasting and effective clinical treatment drugs, resulting in a major economic burden to patients and society. Therefore, it is important to develop more durable and effective drugs for treatment. In recent years, substantial evidence has shown that α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) play a vital role in somatic and orofacial pain. Among them, subunit phosphorylation regulated by protein kinases and interactions with partner proteins promote the activation and trafficking of AMPARs and signal transduction to regulate the expression of AMPARs. The increase of GluA1-containing AMPARs promotes calcium ion influx, further activating protein kinases and auxiliary proteins, which forms a self-feedback loop. This is an important mechanism that promotes chronic pain. The expression of AMPARs in the trigeminal nervous system and the spinal cord nervous system overlaps, and the above mechanism may also participate in regulating orofacial pain. However, research on AMPARs in orofacial neuropathic pain or cancer-related pain is relatively insufficient, and more in-depth research is needed in the future. Furthermore, there is a lack of clinical evidence for AMPAR antagonists to treat pain. Understanding the regulatory mechanisms of the activation and trafficking of AMPARs and precisely intervening in the activation and trafficking of AMPARs may provide effective strategies for the development of new analgesics and offer new insights for treating orofacial pain.