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Aim To explore the effect of berberine (B E) on RSV infected HEp-2 cells and the related mechanism. Methods HEp-2 cells were infected with RSV and treated with BE. Cell viability was assessed using the CCK-8 assay. Protein expression levels of NLRP3, ASC, caspase-1, PINK1, Parkin, Beclinl, p62, LC3 I,LC3 II,and BNIP3 in HEp-2 cells were detected by Western blot. The secretion level of IL-1 p in HEp-2 cells was measured using ELISA. Apoptosis rate and mitochondrial membrane potential of HEp-2 cells were examined by flow cytometry. Mitochondrial ROS (mtROS) in HEp-2 cells was detected through MitoSOX staining. Colocalization of mitochondria and autophagosomes in HEp-2 cells was investigated using immunofluorescence staining. Cyclosporin A was used for validation experiments. Results BE could significantly improve the activity of RSV-infected HEp-2 cells,reduce the apoptosis rate (P < 0. 05), and decrease the activation level of NLRP3 inflammasomes and IL-lp level (P <0. 05); BE improved mitochondrial function by increasing mitochondrial membrane potential and ATP levels,and reduced mtROS. BE significantly promoted the colocalization of mitochondria-autophagosome in RSV infected cells, inducing PINK1/ Parkin and BNIP3 to mediate mitochondrial autophagy; cyclosporine A aggravated RSV infection. Conclusions BE has protective effects on HEp-2 cells infected by RSV. The mechanism may be related to the inhibitory effect of BE on the production of mtROS and the activation of NLRP3 inflammasomes by inducing PINK1/ Parkin and BNIP3-mediated mitochondrial autophagy.
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Objective To design and synthesize autophagic degraders targeting BRD4 based on autophagosome tethering compound (ATTEC) strategy and test their BRD4 degradation activity. Methods BRD4-targeting ATTECs were constructed by conjugating ispinesib that used as a LC3 ligand and JQ1 through a variety of alkane linkers. The final compounds were confirmed by 1H NMR, 13C NMR and ESI-MS, and their degradation activity in different cell lines were tested by Western Blot. Results Five BRD4-ATTEC molecules were successfully synthesized for the first time. Compound 4 showed moderate BRD4 degradation activity in different cell lines. Conclusion The novel BRD4 autophagic degraders were discovered, which expanded the applicability of targeted autophagic degradation via ATTEC.
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The mechanisms underlying autophagic defects in nonalcoholic steatohepatitis (NASH) remain largely unknown. We aimed to elucidate the roles of hepatic cyclooxygenase 1 (COX1) in autophagy and the pathogenesis of diet-induced steatohepatitis in mice. Human nonalcoholic fatty liver disease (NAFLD) liver samples were used to examine the protein expression of COX1 and the level of autophagy. Cox1Δhepa mice and their wildtype littermates were generated and fed with 3 different NASH models. We found that hepatic COX1 expression was increased in patients with NASH and diet-induced NASH mice models accompanied by impaired autophagy. COX1 was required for basal autophagy in hepatocytes and liver specific COX1 deletion exacerbated steatohepatitis by inhibiting autophagy. Mechanistically, COX1 directly interacted with WD repeat domain, phosphoinositide interacting 2 (WIPI2), which was crucial for autophagosome maturation. Adeno-associated virus (AAV)-mediated rescue of WIPI2 reversed the impaired autophagic flux and improved NASH phenotypes in Cox1Δhepa mice, indicating that COX1 deletion-mediated steatohepatitis was partially dependent on WIPI2-mediated autophagy. In conclusion, we demonstrated a novel role of COX1 in hepatic autophagy that protected against NASH by interacting with WIPI2. Targeting the COX1-WIPI2 axis may be a novel therapeutic strategy for NASH.
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Abstract This study focused on the effect and mechanism of Notch signal on pulmonary microvascular endothelial cells (PMVECs) following acute lung injury. PMVECs were cultured in vitro and randomly divided into eight groups. Grouping was based on whether cells were co-cultured with T cells (splenic CD4+T cells were isolated using MACS microbeads) and the level of Notch expression: Normal group and Normal+T cells group, Model group and Model+T cells group, Notch low-expression group and Notch low-expression+T cells group, and Notch overexpression group and Notch overexpression+T cells group. Except for the Normal group and Normal+T cells group, all other groups were treated with 500 μL lipopolysaccharide (1 μg/mL). The expression of VE-cadherin and Zo-1 protein in the Model group (with or without T cells) was lower than that in the normal group (with or without T cells), their expression in the Notch low-expression group (with or without T cells) was significantly increased, and their expression in the Notch overexpression group (with or without T cells) was significantly decreased. Compared with the normal+T cells group, the number of Treg cells in the Notch low-expression+T cells group decreased significantly (P<0.01). The number of Th17 cells in the Notch overexpression+T cells group was higher than that in the Model+T cells group (P<0.01), while the number of Treg cells decreased (P<0.01). Our results demonstrated that activated Notch signal can down-regulate the expression of the tight junction proteins VE-Cadherin and Zo-1 in PMVECs and affect Th17/Treg immune imbalance. Autophagy was discovered to be involved in this process.
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In recent years, the targeted protein degradation technology has developed quickly, with proteolysis-targeting chimera (PROTAC) as the best-known strategy through exploring the ubiquitin-proteasome system. A number of new targeted protein degradation strategies have been emerging to expand the scope of protein degradation technology, including lysosome-targeting chimeras (LYTACs), autophagy-targeting chimeras (AUTACs), autophagosome-tethering compounds (ATTECs) and chimeras based on chaperone-mediated autophagy (CMA). The emerging methodologies have explored another important protein degradation system in eukaryotes-lysosomal systems, such as the endosome-lysosome pathway and the autophagy-lysosome pathway. This review summaries the mechanisms and features of different strategies for targeted protein degradation, with a special emphasis on the new targeted protein degradation technologies, such as their current status, advantages and limitations.
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Aim To investigate the effect of nifedipine on the formation of autophagosomes in hepatoma cell line Huh-7 and its mechanism.Methods Different concentrations of nifedipine were used to interfere with the proliferation of Huh-7 cells in vitro.The effect of nifedipine on the proliferation of Huh-7 cells was detected by cell proliferation experiment and colony formation experiment.The expressions of Beclin1 and LC3B-Ⅱ were detected by Western blot.The effect of nifedipine on the formation of autophagosomes in Huh-7 cells was observed by laser scanning confocal microscopy.Results Nifedipine significantly inhibited the proliferation of Huh-7 cells in a time-and concentration-dependent manner.The IC50 of nifedipine on day 2 was 22.7 mg·L-1.Nifedipine at the concentration of 25 mg·L-1 significantly reduced the colony formation rate of Huh-7 cells compared with the control group, and the inhibition rate of colony formation was(95.46±0.45)%.Western blot analysis showed that nifedipine significantly up-regulated the protein expression levels of Beclin1 and LC3B-Ⅱ.The amount of autophagosomes in nifedipine group cells were more than that of control group, which was observed by laser scanning confocal microscopy.Conclusions Nifedipine significantly inhibits the proliferation of Huh-7 cells and promotes the formation of autophagosomes, which may be related to the up-regulation of Beclin1 protein expression by nifedipine.
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Aim To investigate the effect of nifedipine on the formation of autophagosomes in hepatoma cell line Huh-7 and its mechanism.Methods Different concentrations of nifedipine were used to interfere with the proliferation of Huh-7 cells in vitro.The effect of nifedipine on the proliferation of Huh-7 cells was detected by cell proliferation experiment and colony formation experiment.The expressions of Beclin1 and LC3B-Ⅱ were detected by Western blot.The effect of nifedipine on the formation of autophagosomes in Huh-7 cells was observed by laser scanning confocal microscopy.Results Nifedipine significantly inhibited the proliferation of Huh-7 cells in a time-and concentration-dependent manner.The IC50 of nifedipine on day 2 was 22.7 mg·L-1.Nifedipine at the concentration of 25 mg·L-1 significantly reduced the colony formation rate of Huh-7 cells compared with the control group, and the inhibition rate of colony formation was(95.46±0.45)%.Western blot analysis showed that nifedipine significantly up-regulated the protein expression levels of Beclin1 and LC3B-Ⅱ.The amount of autophagosomes in nifedipine group cells were more than that of control group, which was observed by laser scanning confocal microscopy.Conclusions Nifedipine significantly inhibits the proliferation of Huh-7 cells and promotes the formation of autophagosomes, which may be related to the up-regulation of Beclin1 protein expression by nifedipine.
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Autophagy is a highly conserved intracellular degradation pathway in eukaryotic cells that responds to environmentalchanges. Genetic analyses have shown that more than 40 autophagy-related genes (ATG) are directly involved in thisprocess in fungi. In addition to Atg proteins, most vesicle transport regulators are also essential for each step of autophagy.The present study showed that one Endoplasmic Reticulum protein in Saccharomyces cerevisiae, Tip20, which controlsGolgi-to-ER retrograde transport, was also required for starvation-induced autophagy under high temperature stress. Intip20 conditional mutant yeast, the transport of Atg8 was impaired during starvation, resulting in multiple Atg8 punctadispersed outside the vacuole that could not be transported to the pre-autophagosomal structure/phagophore assembly site(PAS). Several Atg8 puncta were trapped in ER exit sites (ERES). Moreover, the GFP-Atg8 protease protection assayindicated that Tip20 functions before autophagosome closure. Furthermore, genetic studies showed that Tip20 functionsdownstream of Atg5 and upstream of Atg1, Atg9 and Atg14 in the autophagy pathway. The present data show that Tip20,as a vesicle transport regulator, has novel roles in autophagy
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@#Autophagosomes derived from tumor cells have been proved to induce potent T cell response both in mouse and human. In human in vitro study, dendritic cells(DC)loaded with cytomegalovirus(CMV)pp65 antigen-containing DRibble were capable to efficiently re-stimulate pp65-specific T-cell recall responses from freshly isolated or frozen humanperipheral blood mononuclear cell(PBMC). This study developed more robust assays using in vitro expanded antigen-specific T cells that contained a much higher percentage of antigen-specific T cells. DC cross-presentation efficiency of OX40 and CD80 modified pp65-DRibble was detected by intracellular IFN-γ staining. Compared with Ctrl/pp65 DRibble, the percentage of IFN-γ+ in total CD8+ T cells andCD4+ T cells was improvedwith OX40/pp65 DRibbleand CD80/pp65 DRibble stimulation. In addition, vaccine induced IL-12indendritic cells, whichpolarizes Th cells toward the IFN-γ high Th1 phenotype, evaluated by ELISA inco-culture supernatantwas dramatically higher in OX40/pp65 DRibble and CD80/pp65 DRibblegroups than in Ctrl/pp65 DRibble group. These results have implications for the immuneactivity of OX40 and CD80 modified DRibble and choice for prospective clinical use ofDRibble-based cancer immunotherapy.
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Autophagy is an active research area in the biomedical field as its role has been identified in many physiological and pathological processes. Accordingly, there is a growing demand to identify, quantify and manipulate the process accurately. Meanwhile, there is great interest in identifying compounds that modulate autophagy because they may have applications in the treatment of a variety of autophagy-related diseases. In this review, we summarize the current status of autophagy screening systems to facilitate identification of autophagy modulators.
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Objective To observe the quantity change of autophagosomes in podocytes and expressions of autophagy-related gene Beclin-1 and microtubule-associated protein 1 light chain 3 (LC3) in different pathological stages of idiopathic membranous nephropathy (IMN),and to explore how autophagy is related to podocyte injury,the occurrence of proteinuria and the disease progression in IMN.Methods Clinical data of 26 patients who were diagnosed as IMN (14 IMN stage 1 and 12 IMN stage 2) admitted to Zhejiang Provincial people's Hospital from January 2013 to December 2014 were retrospectively analyzed.Normal renal tissue from 15 cases of kidney neoplasms with nephrectomy was collected as control.The changes of kidney tissue pathology were detected after PAS and PASM staining by light microscope.The autophagosomes of podocyte were detected by transmission electron microscopy.Expressions of Beclin-1 and LC3 protein were detected by immunohistochemistry.Expressions of LC3 and synaptopodin were detected by immunofluorescence.The correlation of autophagosomes and clinical pathologic factors in IMN patiens was analyzed.Results There were fewer autophagosomes of podocytes and lower expression of Beclin-1 and LC3 protein in IMN group than those in control group (P=0.034,P=0.011,P=0.013,respectively).Moreover,these effects were more obvious with the development of IMN.Compared with those in control group,autophagosomes,Beclin-1 and LC3 protien were reduced in IMN stage 2 group (P=0.009,P=0.030,P=0.015);the number of autophagosomes and the expressions of LC3 and Beclin-1 were decreased in IMN stage 1 group as well,however statistically insignificant (P=0.352,P=0.087,P=0.128);Comparisons between IMN stage 2 patients and IMN stage 1 patients shown significant difference in the number of autophagosomes (P=0.030),but no significant difference in expressions of Beclin-1 and LC3 (P=0.355,P=0.181).Autophagosomes number was not correlated with serum creatinine,serum urea nitrogen,24-hour urinary protein and eGFR (all P ＞ 0.05).The expressions of synaptopodin and LC3 protein were lower in IMN group than those in control group.Conclusion Autophagy may contribute to podocyte injury and the production of protein urine in IMN,and may be closely related to the progression of disease.
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La enfermedad cardiovascular se mantiene como la principal causa de morbimortalidad a nivel mundial a pesar de los avances científicos y tecnológicos recientes, por esto existe la necesidad de búsqueda de nuevas dianas terapéuticas. La autofagia es un mecanismo de degradación de proteínas y organelos disfuncionales que ocurre en vacuolas especializadas de doble membrana denominadas autofagosomas y que requiere la participación de los lisosomas. Este proceso permite el auto abastecimiento celular de energía a través del reciclaje de diversos substratos energéticos. Se activa en respuesta a diversas formas de estrés, principalmente debido a la ausencia de nutrientes y su presencia ha sido caracterizada en todos los tipos celulares que componen el sistema cardiovascular. Existe una ventana de actividad de autofagia óptima la que se relaciona con la mantención de la homeostasis cardiovascular y su desregulación participa en la patogénesis de diversas patologías cardiovasculares. En este artículo se revisa el curso temporal que llevó el descubrimiento de la autofagia, la contribución al área del Dr. Ohsumi, reciente Premio Nobel de Medicina, los principales conceptos, mecanismos celulares y moleculares de la formación del auto-fagosoma, nodos de regulación y sintetizamos su participación en la homeostasis del corazón y en la patogénesis de las enfermedades cardiovasculares y sus perspectivas futuras.
Cardiovascular disease continues to be the leading cause of morbi-mortality worldwide despite the recent scientific and technological advances. Therefore, more research is needed to discover novel therapeutic targets. Autophagy mediates the removal of dysfunctional proteins and organelles. This process takes place in double-membrane vesicles, named autophagosomes, which later fuse with lysosomes. The mechanism allows self-renewal energy repletion through diverse energy substrate recycling. Diverse forms of cellular stress, mainly nutrient deprivation, activate this process. Autophagy has been widely characterized within the cells of the cardiovascular system. There is a window of optimal autophagy activity implicated in maintaining cardiovascular homeostasis and its dysregulation participates in the pathogenesis of different cardiovascular diseases. In this article, we review the time course of auto-phagy discovery, the Nobel Prize winner Dr. Ohsumi contribution, main concepts, mechanisms involved in autophagosome formation and its regulatory no-des. Additionally, we summarized the role of auto-phagy in cardiovascular homeostasis and pathogenesis and future perspectives.
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Humans , Autophagy , Cardiovascular Diseases/history , Cardiovascular Diseases/metabolism , Cardiovascular Diseases/pathologyABSTRACT
Autophagy is a catabolic process involved in the degradation of a cell's own components for cell growth, development, homeostasis, and the recycling of cellular products. Autophagosome is an essential component in the protozoan parasite during differentiation and encystation. The present study identified and characterized autophagy-related protein (Atg) 3, a member of Atg8 conjugation system, in Acanthamoeba castellanii (AcAtg3). AcAtg3 encoding a 304 amino acid protein showed high similarity with the catalytic cysteine site of other E2 like enzymes of ubiquitin system. Predicted 3D structure of AcAtg3 revealed a hammer-like shape, which is the characteristic structure of E2-like enzymes. The expression level of AcAtg3 did not increase during encystation. However, the formation of mature cysts was significantly reduced in Atg3-siRNA transfected cells in which the production of Atg8-phosphatidylethanolamine conjugate was inhibited. Fluorescent microscopic analysis revealed that dispersed AcAtg3-EGFP fusion protein gathered around autophagosomal membranes during encystation. These results provide important information for understanding autophagic machinery through the lipidation reaction mediated by Atg3 in Acanthamoeba.
Subject(s)
Animals , Rats , Acanthamoeba castellanii/growth & development , Gene Knockdown Techniques , Lipid Metabolism , Models, Molecular , Molecular Sequence Data , Protein Structure, Tertiary , Protozoan Proteins/genetics , RNA, Small Interfering/metabolism , Sequence Analysis, DNA , Spores, Protozoan/growth & development , Ubiquitin-Conjugating Enzymes/geneticsABSTRACT
Objective In the heart,autophagy is important for the turnover of organelles at low basal levels under normal conditions,but is upregulated in response to stresses such as ischemia/reperfusion and in cardiovascular diseases such as heart failure. It can prevent the heart from injury under stress conditions. This study was designed to test the hypothesis that autophagy would be upregulated in the myocardium of children with cyanotic congenital cardiac defects. Methods Eighteen children with cyanotic (n=10) or acyanotic cardiac defects (n=8) who were admitted in our hospital from October 2008 to April 2009 and received surgical treatment were investigated. Samples from the right ventricular myocardium taken immediately after aortic clamping were morphologically studied with transmission electron microscopy for the ultrastructure. Microtubule-associated protein 1 light chain 3 (LC-3) was detected by Western blot analysis in the obtained samples. Results Children with cyanotic cardiac defects had higher oxyhemoglobin saturation before operation than those with acyanotic cardiac defects. Electron microscopy showed that the former group had more mitochondria,disordered arrangement,swollen endoplasmic reticulum and typical autophagosomes in the myocardial cytosol. LC3-II were significantly elevated in patients with cyanotic compared with those with acyanotic congenital cardiac defects (P