The Role of YAP-JNK in the Mitophagy, Migration, and Invasion of Gastric Cancer.

OBJECTIVE: To determine the function of the YAP-JNK-mitophagy signalling pathway in gastric cancer (GC). STUDY DESIGN: An observational study. PLACE AND DURATION OF STUDY: Seventh People's Hospital of Shanghai University of TCM (Traditional Chinese Medicine), between June 2019 and June 2021. METHODOLOGY: Tissues from 30 cases of gastric cancer and corresponding adjacent tissues were collected. RT-qPCR was employed to detect the expression of YAP and JNK in GC samples. MTT, Wound healing and Transwell assays were used to detect changes in GC cell proliferation, migration, and invasion under different stimulation. LC3 immunofluorescence and mitochondrial membrane potential detection were used to analyse the occurrence of mitochondrial autophagy. RESULTS: The expression of YAP and JNK were significantly increased in GC tissues (p=0.024, 0.033). YAP knockdown inhibited GC cell proliferation, migration, and invasion. Further studies showed that YAP affects GC cell function by targeting JNK. In addition, YAP-JNK signalling was found to regulate GC cell proliferation, migration, and invasion mainly through regulating the occurrence of mitophagy. CONCLUSION: These findings revealed that YAP-JNK promotes the development of GC by targeting mitophagy. KEY WORDS: Gastric cancer, YAP, JNK, Autophagy.

ALDH2 Overexpression Alleviates High Glucose-Induced Cardiotoxicity by Inhibiting NLRP3 Inflammasome Activation.

Although the underlying mechanisms of diabetes-induced myocardial injury have not been fully illuminated, the inflammation reaction has been reported intently linked with diabetes. The nucleotide binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome, the key component of pyroptosis, is involved in inflammation reaction, which may be one of the important mechanisms in diabetes-induced myocardial injury. The purpose of this study was to investigate the changes of NLRP3 inflammasome and pyroptosis in high glucose-induced H9C2 cardiac cell injury and investigate whether overexpression of mitochondrial aldehyde dehydrogenase 2 (ALDH2) can reduce the occurrence of pyroptosis. The H9C2 cardiac cells were exposed to 35 mM glucose for 24 h to induce cytotoxicity. Mitochondrial ALDH2 overexpression cardiac cell line was constructed. The results showed in high glucose condition that ALDH2 overexpression significantly increased H9C2 cardiac cell viability, increased mitochondrial ALDH2 activity and protein expression, and reduced mitochondrial reactive oxygen species (ROS) production, 4-hydroxynonenal (4-HNE), and lactate dehydrogenase (LDH) levels; meanwhile, the pyroptosis key components-NLRP3 inflammasome-related proteins, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cysteine-containing aspartate specific protease 1 (Caspase-1), and interleukin-18 (IL-18) protein expressions-were significantly decreased, and IL-18 and interleukin-1ß (IL-1ß) levels were also decreased. In high glucose-induced cardiac cell injury, ALDH2 overexpression may reduce ROS production, thereby inhibiting the activation of NLRP3 inflammation and cell pyroptosis. ALDH2 gene might play the potential role in the treatment of high glucose-induced H9C2 cardiac cell injury.

[Effects of activation of mitochondrial aldehyde dehydrogenase 2 on inflammasome production in high glucose induced A549 cells].

OBJECTIVE: To investigate the effects of activation of mitochondrial aldehyde dehydrogenase 2(ALDH2) on high glucose-induced inflammasome production in alveolar epithelial A549 cells. METHODS: The alveolar epithelial A549 cells were cultured with 25 mmol/L high glucose complete medium and divided into 4 groups: Control group, ALDH2 agonist 20 µmol/L Alda-1 group, ALDH2 antagonist 60 µmol/L Daidzin group, 20 µmol/L Alda-1 + 60 µmol/L Daidzin group. After the cells treated for 24 h, the cell proliferation activity was measured by thiazolyl blue tetrazolium bromide(MTT) colorimetric assaymethod, and the cellular reactive oxygen species(ROS) level were detected by dihydroethidium(DHE) fluorescent staining method, the cell migration ability was performed by cell scratching experiments, the protein expressions of ALDH2 and the core components of inflammasome, nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3), apoptosis-associated speck-like protein containing CARD(ASC) and cysteinyl aspartate specific protease-1(caspase-1) were detected by western blot. RESULTS: Compared with the control group, after Alda-1 activated ALDH2 specifically, the cell proliferation activity did not change significantly, but the oxidative stress level and cell migration rate were significantly decreased(P<0.05). ALDH2 protein expression was significantly increased(P<0.05), the protein expressions of NLRP3, ASC and caspase-1 were significantly decreased(P<0.05). After Daidzin blocked ALDH2 specifically, there were no significant changes in cell proliferation, oxidative stress, cell migration rate, ALDH2 and ASC protein expressions, while NLRP3 protein expression was significantly increased(P<0.05), and caspase-1 protein expression was significantly decreased(P<0.05). Compared with Alda-1 group, there was no significant changes in cell proliferation and oxidative stress in Alda-1+Daidzin group, cell migration rate was significantly increased(P<0.05), ALDH2 protein expression was decreased(P<0.05), and the protein expressions of NLRP3, ASC and caspase-1 were significantly increased(P<0.05). CONCLUSION: Increasing ALDH2 expression in alveolar epithelial A549 cells may attenuate high glucose-induced cellular inflammatory reaction, possibly through reducing cellular ROS level and reducing inflammasome expression.