scholarly journals Leflunomide inhibits inflammation and apoptosis of H9c2 cells induced by hydrogen peroxide

2021 ◽  
Vol 20 (9) ◽  
pp. 1887-1893
Author(s):  
Jing Xie ◽  
Yeyu Qin ◽  
Cheng Yu
Keyword(s):  
Myocardial Infarction ◽  
Molecular Mechanisms ◽  
Cell Injury ◽  
Inflammatory Responses ◽  
Control Group ◽  
Tunel Staining ◽  
H9c2 Cell ◽  
H9c2 Cells ◽  
Tnf Α

 Purpose: To investigate the effects of leflunomide (Lef) on inflammatory response and apoptosis after myocardial infarction, and to explore its molecular mechanisms of action.Methods: H2O2 and H9c2 cells were used to establish myocardial cell injury model in vitro. H9c2 cells were divided into 3 groups: control group, H2O2 group, H2O2 + Lef group. The CCK-8 assay was used to determine the optimal concentration of H2O2 and Lef, while the expressions of TNF-α, IL-6, IL-1β, Bcl-2, Bax, Bad, TLR4, IκB-α, P65 and p-P65 were evaluated by Western blot. PCI was utilized to detect the expression of TNF-α, IL-6, IL-1β, Bcl-2, Bax and Bad mRNA. The levels of TNF-α, IL-6 and IL-1β in supernatant were assessed by ELISA, while apoptosis of the three groups was evaluated by TUNEL staining and flow cytometry.Results: Compared with H2O2 group, TNF-α, IL-6, IL-1β, Bax and Bad expressions in H2O2+Lef group were significantly reduced (p < 0.05), but Bcl-2 expression significantly increased. The levels of TNF-α and IL-6 and IL-1β in supernatant of H2O2 + Lef group were also decreased compared to those in the H2O2 group (p < 0.05). In addition, TUNEL-positive cells and apoptotic rates were significantly reduced after treatment with Lef. Moreover, Lef inhibited expression of TLR4 and p-P65, but activated expression of IκB-α, indicating that Lef inhibited TLR4/NF-κB pathway (p < 0.05).Conclusion: The results show that Lef inhibits H2O2-induced H9c2 cell apoptosis and inflammatory responses by inhibiting TLR4/NF-κB pathway. These findings may provide new targets for the treatment of myocardial infarction.

Exploring Cardioprotective Potential of Esculetin Against Isoproterenol Induced Myocardial Infarction in Rats: In Vivo and in Vitro Evidence

2021 ◽  
Author(s):  
Pullaiah Chitikela P ◽  
Vinod K Nelson ◽  
Sushma R ◽  
Narasimha Kumar GV ◽  
Thyagaraju K
Keyword(s):  
Myocardial Infarction ◽  
Body Weight ◽  
Lysosomal Enzymes ◽  
H9c2 Cell ◽  
Rna Expression ◽  
Cell Necrosis ◽  
Tnf Α ◽  
Intracellular Ros ◽  
Membrane Bound

Abstract BackgroundEsculetin is a natural coumarin derivative from various plants with multiple pharmacological effects. Hence, the present study was undertaken to explore the cardio protective potential of esculetin against isoproterenol induced myocardial toxicity in rats. Methods The treatment schedule was fixed for 28 days and the rats were divided into five groups of six each. Rats of group I received the normal saline and served as normal control, group II was received ISO (100mg/kg body weight) for last two consecutive days of the study and served as disease control. Groups III and IV received esculetin 10 and 20 mg/kg body weight respectively once a day per oral for 28 days along with ISO for last two consecutive days of the study. Cardiac biomarkers such as CK-MB and LDH, membrane bound Na+ /K+ ATPases activity, myocardial lysosomal enzymes activity and tissue antioxidants status were estimated in the heart tissue samples. The histopathological changes in the myocardium were also assessed. Further, DPPH assay was done to evaluate the free radicals scavenging potential of esculetin. Cytoxicity assay, intracellular ROS levels by DCFDA assay and m-RNA expression of TNF-α, IL-6 and NF-κB by quantitative RT-PCR in H9c2 cell lines.ResultsThe increased levels of CK-MB, LDH, LPO, myocardial lysosomal enzymes and membrane bound Na+ /K+ ATPase levels by ISO administration was significantly increased with concomitant decrease in tissue antioxidant enzymes such as GSH, Catalase, and SOD. Pre-treatment with esculetin for 28 days has significantly decreased the levels of cardiac bio-markers, lysosomal enzymes, membrane bound Na+ /K+ ATPase levels as well as Lipid peroxides which is in contrary to the ISO group. Amelioration of the antioxidant levels were also found in esculetin treated groups. Histopathological examination of heart reveals that myocardial degeneration, mononuclear cell infiltration was noticed in ISO treated rats, whereas the same was restored with esculetin treatment. In H9C2 cell lines esculetin could effectively reduced intracellular ROS inhibition and m-RNA expression of pro-inflammatory cytokines including TNF-α, IL-6 and NF-κB to prevent apoptosis or cell necrosis. Conclusion The study provides the evidence of cardioprotective potentials of esculetin against isoproterenol induced myocardial infarction by antioxidant and myocardial membrane stabilization along with in vitro protection from arsenic induced ROS cell necrosis or apoptosis in H9C2 cells.

Dapagliflozin protects H9c2 cells against injury induced by lipopolysaccharide via suppression of CX3CL1/CX3CR1 axis and NF-κB activity

2021 ◽  
Vol 14 ◽  
Author(s):  
Yousef Faridvand ◽  
Maryam Nemati ◽  
Elham Zamani-Gharehchamani ◽  
Hamid Reza Nejabati ◽  
Arezoo Rezaie Nezhad Zamani ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Viability ◽  
Sglt2 Inhibitor ◽  
Binding Activity ◽  
Control Group ◽  
H9c2 Cell ◽  
H9c2 Cells ◽  
Dna Binding Activity ◽  
Inflammatory Conditions ◽  
Tnf Α

Background: Dapagliflozin, a selective Sodium-glucose cotransporter-2 (SGLT2) inhibitor, has been shown to play a key role in the control and management of the metabolic and cardiac disease. Objective: The current study aims to address the effects of dapagliflozin on the expression of fractalkine (FKN), known as CX3CL1, and its receptors CX3CR1, Nuclear factor-kappa B(NF-κB) p65 activity, Reactive oxygen species (ROS), and inflammation in LPS-treated H9c2 cell line. Methods: H9c2 cells were cultured with lipopolysaccharide (LPS) to establish a model of LPS-induced damage and then subsequently were treated with dapagliflozin for 72 h. Our work included measurement of cell viability (MTT), Malondialdehyde (MDA), intracellular ROS, tumor necrosis factor-α (TNF-α), NF-κB activity, and expression CX3CL1/CX3CR1. Results: The results showed that LPS-induced reduction of cell viability was successfully rescued by dapagliflozin treatment. The cellular levels of MDA, ROS, and TNF-α, as an indication of cellular oxidative stress and inflammation, were significantly elevated in H9c2 cells compared to the control group. Furthermore, dapagliflozin ameliorated inflammation and oxidative stress through the modulation of the levels of MDA, TNF-α, and ROS. Correspondingly, dapagliflozin reduced the expression of CX3CL1/CX3CR1, NF-κB p65 DNA binding activity and it also attenuated nuclear acetylated NF-κB p65 in LPS-induced injury in H9c2 cells compared to untreated cells. Conclusion: These findings shed light on the novel pharmacological potential of dapagliflozin in the alleviation of LPS-induced CX3CL1/CX3CR1-mediated injury in inflammatory conditions such as sepsis-induced cardiomyopathy.

scholarly journals Skullcapflavone I protects cardiomyocytes from hypoxia-caused injury through up-regulation of lincRNA-ROR

2019 ◽  
Vol 33 ◽  
pp. 205873841985753 ◽  
Author(s):  
Zhenxiao Zhang ◽  
Hui Li ◽  
Mingyang Liu ◽  
Jianshuai He ◽  
Xiaotian Zhang ◽  
...  
Keyword(s):  
Cell Apoptosis ◽  
Cell Injury ◽  
Mitogen Activated Protein Kinase ◽  
Cell Counting ◽  
H9c2 Cell ◽  
Erk Pathway ◽  
H9c2 Cells ◽  
Scutellaria Baicalensis Georgi ◽  
Protein Levels

Myocardial infarction (MI) is a serious heart disease in which cardiomyocytes are damaged, caused by hypoxia. This study explored the possible protective activity of Skullcapflavone I (SF I), a flavonoid isolated from the root of Scutellaria baicalensis Georgi, on hypoxia-stimulated cardiomyocytes cell injury in vitro. Viability and apoptosis of H9c2 cells and primary cardiomyocytes were tested using cell counting kit–8 (CCK-8) assay and Guava Nexin Reagent, respectively. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to measure the long non-coding RNA regulator of reprogramming (lincRNA-ROR) expression. si-ROR was transfected to knockdown lincRNA-ROR. Western blotting was conducted to assess the protein levels of key molecules related to cell proliferation, apoptosis, and mitogen-activated protein kinase/extracellular signal–regulated kinase (MEK/ERK) pathway. We discovered that hypoxia stimulation obviously reduced H9c2 cell and primary cardiomyocytes’ viability and proliferation, but promoted cell apoptosis. SF I treatment mitigated the cell viability and proliferation inhibition, as well as cell apoptosis caused by hypoxia. Moreover, SF I promoted the hypoxia-caused up-regulation of lincRNA-ROR in H9c2 cells and primary cardiomyocytes. Knockdown of lincRNA-ROR reversed the influence of SF I on hypoxia-stimulated H9c2 cells and primary cardiomyocytes. Besides, SF I activated MEK/ERK pathway in H9c2 cells and primary cardiomyocytes via up-regulating lincRNA-ROR. To sum up, our research verified the beneficial activity of SF I on hypoxia-caused cardiomyocytes injury. SF I protected cardiomyocytes from hypoxia-caused injury through up-regulation of lincRNA-ROR and activation of MEK/ERK pathway.

scholarly journals Ononin Alleviates Doxorubicin-Induced Cardiotoxicity by Inhibiting ER Stress Through Activation of SIRT3

2021 ◽  
Author(s):  
Shimin Sun ◽  
Jingfan Weng ◽  
Qi Yang ◽  
Xingxiao Huang ◽  
Hanlin Zhang ◽  
...  
Keyword(s):  
Er Stress ◽  
Myocardial Injury ◽  
Molecular Mechanisms ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Protective Effects ◽  
H9c2 Cells ◽  
Rat Cardiomyocytes

Abstract Introduction Doxorubicin (DOX) is a powerful anthracycline antineoplastic drug, but the clinical application of DOX is seriously limited by its dose-dependent cardiotoxicity. Ononin is a natural isoflavone glycoside and plays a key role in modulating apoptosis related signaling pathways. The aim of this study was to assess the possible cardioprotective effects of Ononin in DOX-induced cardiotoxicity and the underlying molecular mechanisms. Materials and methods Wistar rats were treated with normal saline, DOX with or without Ononin. After the last administration, cardiac function was evaluated by echocardiography. Rats were then sacrificed for histological and TUNEL analyses, with immunological detection for β-actinin, Bax, Bcl-2, GRP78, CHOP and SIRT3. An enzyme-linked immunosorbent assay was performed to assess the myocardial injury markers. H9C2 cells were treated with vehicle, DOX with or without Ononin. Then, 3-TYP was used to find out the relationship between ER stress and SIRT3. Results Ononin treatment ameliorated DOX-induced myocardial injury as demonstrated by echocardiography. Ononin partially restored DOX-induced cardiac dysfunction, both LVEF and LVFS were increased under the cotreatment of Ononin. Ononin also inhibited DOX-induced ER stress and apoptosis in rat cardiomyocytes and H9C2 cells. DOX group had a higher Bax/Bcl-2 ratio, GRP78 and CHOP expression then control group, but Ononin treatment improved these results. This effect was associated with SIRT3 activity, moreover, selective inhibition of SIRT3 blocked the protective effects of Ononin. Conclusion In the present study, we tested the hypothesis that Ononin may protect against DOX-induced cardiomyopathy through ER stress both in vitro and in vivo. Ononin is able to protect against DOX-induced cardiotoxicity by inhibiting ER stress and apoptosis, this effect may via stimulation of the SIRT3 pathway.

scholarly journals Melatonin Protects Cardiomyocytes from Oxygen Glucose Deprivation And Reperfusion-Induced Injury by Inhibiting Rac1/JNK/Foxo3a/Bim Signaling Pathway

2021 ◽  
Author(s):  
Yulin Wang ◽  
Ying Jian ◽  
Xiaofu Zhang ◽  
Bin Ni ◽  
Mingwei Wang ◽  
...  
Keyword(s):  
Protective Effect ◽  
Signaling Pathway ◽  
Cell Injury ◽  
Ischemia Reperfusion ◽  
Glucose Deprivation ◽  
Oxygen Glucose Deprivation ◽  
H9c2 Cell ◽  
Protective Mechanism ◽  
H9c2 Cells

Abstract Melatonin has been shown to exert protective effect during myocardial ischemia/reperfusion (I/R). However, the underlying mechanism is not completely understood. Using the oxygen-glucose deprivation and reperfusion (OGD/R) model of H9c2 cells in vitro, we found that melatonin alleviated OGD/R-induced H9c2 cell injury via inhibiting Foxo3a/Bim signaling pathway. Inhibition of Rac1 activation contributed to the protective effect of melatonin against OGD/R injury in H9c2 cells. Additionally, melatonin inhibited OGD/R-activated Foxo3a/Bim signaling pathway through inactivation of Rac1. Furthermore, JNK inactivation was responsible for Rac1 inhibition-mediated inactivation of Foxo3a/Bim signaling pathway and decreased cell injury in melatonin-treated H9c2 cells. Taken together, these findings identified a Rac1/JNK/Foxo3a/Bim signaling pathway in melatonin-induced protective effect against OGD/R injury in H9c2 cells. This study provided a novel insight into the protective mechanism of melatonin against myocardial I/R injury.

Inhibition of microRNA-181a-5p Protects H9c2 Cells from Hypoxia-Induced Injury Through Up-Regulating Sirtuin 1 Expression

2020 ◽  
Vol 10 (5) ◽  
pp. 682-689
Author(s):  
Qin He ◽  
Rui Dai ◽  
Xiaoju Xiong ◽  
Jinhua Liu ◽  
Zhonghan He ◽  
...  
Keyword(s):  
Cell Injury ◽  
Sirtuin 1 ◽  
Luciferase Reporter ◽  
H9c2 Cell ◽  
Inflammatory Factor ◽  
H9c2 Cells ◽  
Creatine Kinase Mb ◽  
Gene Assay ◽  
Hypoxia Treatment

Myocardial infarction (MI), a life-threatening cardiac event, results in extreme damage to the heart muscle. In this study, we were committed to exploring the role and related mechanisms of microRNA-181a-5p (miR-181a-5p) in MIin vitro. Firstly, we established the MIin vitro cell model by subjecting H9c2 cells to hypoxia. We found that miR-181a-5p was significantly increased in hypoxia-induced H9c2 cells. Then, TargetScan and dual luciferase reporter gene assay confirmed the binding sites between Sirtuin 1 (SIRT1) and miR-181a-5p. SIRT1 was significantly reduced in hypoxia-induced H9c2 cells. Next, we explored the effect of miR-181a-5p inhibitor on hypoxiainduced H9c2 cell injury. The findings indicated that miR-181a-5p inhibitor significantly reduced creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI) production enhanced by hypoxia treatment. Moreover, miR-181a-5p inhibitor increased mitochondrial viability in hypoxia-induced H9c2 cells. MTT assay showed that miR-181a-5p inhibitor enhanced hypoxia-induced H9c2 cell viability, and flow cytometry assay indicated that miR-181a-5p inhibitor reduced H9c2 cell apoptosis. ELISA assay indicated that compared with hypoxia treatment group, miR-181a-5p inhibitor decreased the secretion of inflammatory factor such as IL-6, TNF-α and IL-1β . Finally, Western blot assay showed that miR-181a-5p inhibitor decreased the expression of p-p65, indicating the inhibition on NF- κB signaling pathway activation. However, all these effects of miR-181a-5p inhibitor on hypoxia-induced H9c2 cells were reversed by SIRT1-siRNA. Taken together, miR-181a-5p inhibitor protected against hypoxia-induced H9c2 cell injury by targeting SIRT1.

scholarly journals Effect of Allicin against Ischemia/Hypoxia-Induced H9c2 Myoblast Apoptosis via eNOS/NO Pathway-Mediated Antioxidant Activity

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Lina Ma ◽  
Shangke Chen ◽  
Shaochun Li ◽  
Lijuan Deng ◽  
Yikui Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antioxidant Activity ◽  
Protective Effect ◽  
Molecular Mechanisms ◽  
Cell Activity ◽  
Biologically Active ◽  
H9c2 Cell ◽  
H9c2 Cells ◽  
No Release

Allicin (2-propene-1-sulfinothioic acid S-2-propenyl ester, diallyl thiosulfinate) is the main biologically active ingredient in garlic. The present study investigated the protective effect of allicin against cardiomyocyte apoptosis that was induced by ischemia in vitro and the potential molecular mechanisms that were involved in this antiapoptotic effect. The results indicated that allicin increased H9c2 cell activity and attenuated the rate of apoptosis that was induced by ischemia/hypoxia. Intracellular calcium concentrations significantly decreased in the allicin-treated groups. Bax expression significantly decreased, and Bcl-2 expression increased in allicin-treated rats. Nitric oxide blockade significantly inhibited these effects. Allicin also increased the activity of SOD and NO release and decreased MDA levels. Allicin significantly increased the expression of eNOS, Nrf2, and HO-1 proteins. Collectively, these findings demonstrate that allicin protects H9c2 cells against apoptosis, and this protective effect appears to occur via eNOS/NO pathway-mediated antioxidant activity.

scholarly journals Ononin alleviates Doxorubicin-induced cardiotoxicity by inhibiting ER stress through activation of SIRT3

2021 ◽  
Author(s):  
Shimin Sun ◽  
Jingfan Weng ◽  
Qi Yang ◽  
Xingxiao Huang ◽  
Zhenzhu Sun ◽  
...  
Keyword(s):  
Er Stress ◽  
Myocardial Injury ◽  
Molecular Mechanisms ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Protective Effects ◽  
H9c2 Cells ◽  
Rat Cardiomyocytes

Abstract Introduction Doxorubicin (DOX) is a powerful anthracycline antineoplastic drug, but the clinical application of DOX is seriously limited by its dose-dependent cardiotoxicity. Ononin is a natural isoflavone glycoside and plays a key role in modulating apoptosis related signaling pathways. The aim of this study was to assess the possible cardioprotective effects of Ononin in DOX-induced cardiotoxicity and the underlying molecular mechanisms. Materials and methods Wistar rats were treated with normal saline, DOX with or without Ononin. After the last administration, cardiac function was evaluated by echocardiography. Rats were then sacrificed for histological and TUNEL analyses, with immunological detection for β-actinin, Bax, Bcl-2, GRP78, CHOP and SIRT3. An enzyme-linked immunosorbent assay was performed to assess the myocardial injury markers. H9C2 cells were treated with vehicle, DOX with or without Ononin. Then, 3-TYP was used to find out the relationship between ER stress and SIRT3. Results Ononin treatment ameliorated DOX-induced myocardial injury as demonstrated by echocardiography. Ononin partially restored DOX-induced cardiac dysfunction, both LVEF and LVFS were increased under the cotreatment of Ononin. Ononin also inhibited DOX-induced ER stress and apoptosis in rat cardiomyocytes and H9C2 cells. DOX group had a higher Bax/Bcl-2 ratio, GRP78 and CHOP expression then control group, but Ononin treatment improved these results. This effect was associated with SIRT3 activity, moreover, selective inhibition of SIRT3 blocked the protective effects of Ononin. Conclusion In the present study, we tested the hypothesis that Ononin may protect against DOX-induced cardiomyopathy through ER stress both in vitro and in vivo. Ononin is able to protect against DOX-induced cardiotoxicity by inhibiting ER stress and apoptosis, this effect may via stimulation of the SIRT3 pathway.

scholarly journals The Exosomal lncRNA KLF3-AS1 From Ischemic Cardiomyocytes Mediates IGF-1 Secretion by MSCs to Rescue Myocardial Ischemia-Reperfusion Injury

2021 ◽  
Vol 8 ◽  
Author(s):  
Gecai Chen ◽  
Aihuan Yue ◽  
Meixiang Wang ◽  
Zhongbao Ruan ◽  
Li Zhu
Keyword(s):  
Myocardial Ischemia ◽  
Myocardial Injury ◽  
Cell Injury ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
H9c2 Cell ◽  
H9c2 Cells ◽  
Myocardial Ischemia Reperfusion

The purpose of the study was to explore the mechanism by which myocardial ischemia-reperfusion (I/R) injury-induced exosomes modulate mesenchymal stem cells (MSCs) to regulate myocardial injury. In this study, we established an I/R injury model in vivo and a hypoxia-reoxygenation (H/R) model in vitro. Then, exosomes isolated from H/R-exposed H9c2 cells were characterized using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blot analysis. CCK-8 assays and flow cytometry were performed to assess cell injury. ELISA was applied to determine the level of insulin-like growth factor 1 (IGF-1). Echocardiography was used to assess cardiac function in vivo. HE staining and TUNEL assays were conducted to analyze myocardial injury in vivo. In the present study, H/R-exposed H9c2 cells induced IGF-1 secretion from MSCs to inhibit cell myocardial injury. Moreover, exosomes derived from H/R-exposed H9c2 cells were introduced to MSCs to increase IGF-1 levels. The lncRNA KLF3-AS1 was dramatically upregulated in exosomes derived from H/R-treated H9c2 cells. Functional experiments showed that the exosomal lncRNA KLF3-AS1 promoted IGF-1 secretion from MSCs and increased H9c2 cell viability. In addition, miR-23c contains potential binding sites for both KLF3-AS1 and STAT5B, and miR-23c directly bound to the 3'-UTRs of KLF3-AS1 and STAT5B. Furthermore, the lncRNA KLF3-AS1 promoted IGF-1 secretion from MSCs and rescued myocardial cell injury in vivo and in vitro by upregulating STAT5B expression. The lncRNA KLF3-AS1 may serve as a new direction for the treatment of myocardial I/R injury.

TNF-α Suppresses Autophagic Flux in Acinar Cells in IgG4-Related Sialadenitis

2019 ◽  
Vol 98 (12) ◽  
pp. 1386-1396 ◽  
Author(s):  
X. Hong ◽  
S.N. Min ◽  
Y.Y. Zhang ◽  
Y.T. Lin ◽  
F. Wang ◽  
...  
Keyword(s):  
Acinar Cell ◽  
Cell Injury ◽  
Ex Vivo ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Autophagic Flux ◽  
C6 Cells ◽  
Tnf Α ◽  
Α Level

IgG4-related sialadenitis (IgG4-RS) is a newly recognized immune-mediated systemic fibroinflammatory disease that affects salivary glands and leads to hyposalivation. Tumor necrosis factor–α (TNF-α) is a critical proinflammatory cytokine involved in several salivary gland disorders, but its role and mechanism regarding acinar cell injury in IgG4-RS are unknown. Here, we found that TNF-α level was significantly increased in serum and submandibular gland (SMG) of patients and that serum TNF-α level was negatively correlated with saliva flow rate. Ultrastructural observations of IgG4-RS SMGs revealed accumulation of large autophagic vacuoles, as well as dense fibrous bundles, decreased secretory granules, widened intercellular spaces, swollen mitochondria, and expanded endoplasmic reticulum. Expression levels of LC3 and p62 were both increased in patients’ SMGs. TNF-α treatment led to elevated levels of LC3II and p62 in both SMG-C6 cells and cultured human SMG tissues but did not further increase their levels when combined with bafilomycin A1 treatment. Moreover, transfection of Ad-mCherry-GFP-LC3B in SMG-C6 cells confirmed the suppression of autophagic flux after TNF-α treatment. Immunofluorescence imaging revealed that costaining of LC3 and the lysosomal marker LAMP2 was significantly decreased in patients, TNF-α–treated SMG-C6 cells, and cultured human SMGs, indicating a reduction in autophagosome-lysosome fusion. Furthermore, the ratio of pro/mature cathepsin D was elevated in vivo, ex vivo, and in vitro. TNF-α also appeared to induce abnormal acidification of lysosomes in acinar cells, as assessed by lysosomal pH and LysoTracker DND-26 fluorescence intensity. In addition, TNF-α treatment induced transcription factor EB (TFEB) redistribution in SMG-C6 cells, which was consistent with the changes observed in IgG4-RS patients. TNF-α increased the phosphorylation of extracellular signal–regulated kinase (ERK) 1/2, and inhibition of ERK1/2 by U0126 reversed TNF-α–induced TFEB redistribution, lysosomal dysfunction, and autophagic flux suppression. These findings suggest that TNF-α is a key cytokine related to acinar cell injury in IgG4-RS through ERK1/2-mediated autophagic flux suppression.

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