TXNIP knockdown ameliorates hepatic ischemia/reperfusion injury by inhibiting apoptosis and improving mitochondrial dysfunction via HIF-1α.

This study aims to investigate whether thioredoxin-interacting protein (TXNIP) regulates cell viability, cell apoptosis and mitochondrial damage in OGD/R-induced hepatocytes and to explore its underlying mechanism. AML12 cells were cultured under oxygen-glucose deprivation/reperfusion (OGD/R) conditions. TXNIP mRNA was detected using qRT-PCR, and the TXNIP protein was analyzed using western blotting. TXNIP-targeted short hairpin RNA (sh-TXNIP) lentivirus was used to infect the AML12 cells. CCK8 and TUNEL assays were applied to detect cell viability and apoptosis, respectively. DCFH-DA probe was used to determine reactive oxygen species (ROS) release level, and JC-1 probe was used to evaluate mitochondrial membrane potential (MMP). The localization of TXNIP and HIF-1α was observed using immunofluorescence. Our results showed that TXNIP markedly increased in AML12 cells treated with OGD/R. TXNIP knockdown increased cell viability and reduced cell apoptosis under OGD/R treatment. Moreover, MMP significantly increased and ROS release decreased in cells after TXNIP knockdown under OGD/R treatment. Additionally, TXNIP knockdown markedly increased the expression of HIF-1α. HIF-1α exhibited nuclear translocation following OGD/R induction, and TXNIP knockdown further promoted it. Compared with the OGD/R + sh-TXNIP group, HIF-1α agonist ML228 inhibited cell apoptosis and ROS release, and increased MMP. However, HIF-1α inhibitor PX478 had the opposite effect. In summary, TXNIP deletion ameliorated AML12 cell injury caused by OGD/R via promoting HIF-1α expression and nuclear translocation, manifested by inhibiting cell apoptosis and alleviating mitochondrial dysfunction.

METTL3 Modulates TXNIP Expression to Affect the Activation of NLRP3 Inflammasome in Hepatic Cells Under Oxygen-Glucose Deprivation/Reperfusion Injury.

Hepatic ischemia-reperfusion (I/R) injury is still a major risk factor and unsolved problem in hepatic surgery. Methyltransferase-like 3 (METTL3), an important m6A-modified methylase, regulates inflammation and cellular stress response. In this study, we demonstrated the special role of METTL3 and its underlying mechanism in hepatic I/R injury. In the mouse model of hepatic I/R and in the oxygen-glucose deprivation and reoxygenation (OGD/R)-induced AML12 and NCTC 1469 cells, the expression of METTL3 was significantly upregulated. Inhibition of METTL3 in OGD/R-induced AML12 and NCTC 1469 cells both increased the cell viability, declined the cell apoptosis, and decreased the reactive oxygen species (ROS) and the release levels of interleukin-1ß (IL-1ß) and interleukin-18 (IL-18), diminishing NLRP3 and Caspase1-p20 expressions. Moreover, METTL3 positively modulated TXNIP expression in an m6A manner. TXNIP overexpression reversed the effects of METTL3 knockdown on OGD/R-induced injury in AML12 cells. Furthermore, inhibition of NLRP3 inflammasome activity contributed to the protective effects of TXNIP knockdown in OGD/R-induced AML12 cells. In conclusion, METTL3 knockdown alleviated OGD/R-induced hepatocyte injury, and the specific mechanism was associated with the inhibition of NLRP3 inflammasome activation, which was attributed to the reduction of TXNIP in an m6A-dependent manner.

STING Agonist cGAMP Attenuates Sleep Deprivation-Induced Neuroinflammation and Cognitive Deficits via TREM2 Up-Regulation.

Sleep deprivation (SD) has been associated with several adverse effects, including cognitive deficit. Emerging evidence suggests microglia-associated neuroinflammation is a potential trigger of cognitive deficit after SD. Stimulator of interferon genes (STING) constitutes an important factor in host immune response to pathogenic organisms and is found in multiple cells, including microglia. STING is involved in neuroinflammation during neuronal degeneration, although how STING signaling affects SD-induced neuroinflammation remains unexplored. In the present study, the chronic sleep restriction (CSR) model was applied to examine the effects of STING signaling on cognition. The results revealed that cGAMP, a high-affinity and selective STING agonist, significantly improved cognitive deficit, alleviated neural injury, and relieved neuroinflammation in CSR mice by activating the STING-TBK1-IRF3 pathway. Moreover, triggering receptor expressed on myeloid cells 2 (TREM2) was upregulated in CSR mice treated with cGAMP, and this effect was abolished by STING knockout. TREM2 upregulation induced by cGAMP regulated the microglia from pro-inflammatory state to anti-inflammatory state, thereby relieving neuroinflammation in CSR mice. These findings indicate cGAMP-induced STING signaling activation alleviates SD-associated neuroinflammation and cognitive deficit by upregulating TREM2, providing a novel approach for the treatment of SD-related nerve injury.