GSK621 attenuates oxygen glucose deprivation/re-oxygenation-induced myocardial cell injury via AMPK-dependent signaling

AMPK and NRF2: Interactive players in the same team for cellular homeostasis?

NRF2 (Nuclear factor E2 p45-related factor 2) is a stress responsive transcription factor lending cells resilience against oxidative, xenobiotic, and also nutrient or proteotoxic insults. AMPK (AMP-activated kinase), considered as prime regulator of cellular energy homeostasis, not only tunes metabolism to provide the cell at any time with sufficient ATP or building blocks, but also controls redox balance and inflammation. Due to observed overlapping cellular responses upon AMPK or NRF2 activation and common stressors impinging on both AMPK and NRF2 signaling, it is plausible to assume that AMPK and NRF2 signaling may interdepend and cooperate to readjust cellular homeostasis. After a short introduction of the two players this narrative review paints the current picture on how AMPK and NRF2 signaling might interact on the molecular level, and highlights their possible crosstalk in selected examples of pathophysiology or bioactivity of drugs and phytochemicals.

Arrb2 causes hepatic lipid metabolism disorder via AMPK pathway based on metabolomics in alcoholic fatty liver

BACKGROUND AND AIMS

Alcoholic fatty liver (AFL) is an early form of alcoholic liver disease (ALD) that usually manifests as lipid synthesis abnormalities in hepatocytes. β-arrestin2 (Arrb2) is involved in multiple biological processes. The present study aimed to explore the role of Arrb2 in the regulation of lipid metabolism in AFL and the underlying mechanism and identify potential targets for the treatment of AFL.

METHODS

The expression of Arrb2 was detected in liver tissues obtained from AFL patients and Gao-binge AFL model mice. In addition, we specifically knocked down Arrb2 in AFL mouse liver in vivo and used Arrb2-siRNA or pEX3-Arrb2 to silence or overexpress Arrb2 in AML-12 cells in vitro to explore the functional role and underlying regulatory mechanism of Arrb2 in AFL. Finally, we investigated whether Arrb2 could cause changes in hepatic lipid metabolites, thereby leading to dysregulation of lipid metabolism based on liquid chromatography-mass spectrometry (LC-MS) analysis.

RESULTS

Arrb2 was up-regulated in the livers of AFL patients and AFL mice. The in vivo and in vitro results confirmed that Arrb2 could induce lipid accumulation and metabolism disorders. Mechanistically, Arrb2 induced hepatic metabolism disorder via AMP-activated protein kinase (AMPK) pathway. The results of LC-MS analysis revealed that hepatic lipid metabolites with the most significant differences were primary bile acids.

CONCLUSIONS

Arrb2 induces hepatic lipid metabolism disorders via AMPK pathway in AFL. On one hand, Arrb2 increases fatty acid synthesis. On the other hand, Arrb2 could increase the cholesterol synthesis, thereby leading to the up-regulation of primary bile acid levels.

Circular RNA circ_0010729 Knockdown Attenuates Oxygen-Glucose Deprivation-Induced Human Cardiac Myocytes Injury by miR-338-3p/CALM2 Axis

ABSTRACT

Circular RNAs have pivotal roles in cardiovascular disease. The injury of cardiac myocytes is associated with occurrence of cardiovascular disease. Circular RNA hsa_circ_0010729 (circ_0010729) is associated with cardiac myocytes injury. However, the mechanism of circ_0010729 in cardiac myocytes injury remains largely unclear. In our study, cardiac myocytes were treated by oxygen-glucose deprivation (OGD). The abundances of circ_0010729, microRNA-338-3p (miR-338-3p), and calmodulin 2 (CALM2) were detected by quantitative reverse transcription polymerase chain reaction or Western blot. OGD-induced damage in AC16 cells was assessed by cell viability, apoptosis, and autophagy using Cell Counting Kit-8, flow cytometry, and Western blot analyses. The target relationship of miR-338-3p and circ_0010729 or CALM2 was explored by starBase and dual-luciferase reporter analysis. Our results showed that the circ_0010729 level was enhanced in OGD-treated AC16 cells and murine primary cardiac myocytes. circ_0010729 silence weakened OGD-induced viability inhibition and promotion of apoptosis and autophagy in AC16 cells and murine primary cardiac myocytes. miR-338-3p was sponged by circ_0010729 and miR-338-3p knockdown alleviated the effect of circ_0010729 silence on OGD-induced damage. miR-338-3p directly targeted CALM2 to inhibit OGD-induced damage in AC16 cells. circ_0010729 could regulate CALM2 expression by sponging miR-338-3p. Collectively, circ_0010729 interference mitigated OGD-induced damage in cardiac myocytes through increasing cell viability and inhibiting apoptosis and autophagy by regulating miR-338-3p/CALM2 axis. This study indicated circ_0010729 might act as a target for treatment of cardiovascular disease.

Petatewalide B alleviates oxygen‑glucose deprivation/reoxygenation‑induced neuronal injury via activation of the AMPK/Nrf2 signaling pathway

Neuronal injury is a common, and critical, occurrence in clinical ischemic strokes, and can cause irreversible brain damage. However, the precise pathological mechanisms underlying this condition and effective treatment remain unclear. Increasing evidence shows that the nuclear factor erythroid 2‑related factor 2 (Nrf2)/activated protein kinase (AMPK) signaling pathway serves a significant role in neuronal injury and is involved in neuroprotection. The present study demonstrated that petatewalide B, the active constituent of Petasites japonicus, otherwise known as butterbur, can alleviate oxygen‑glucose deprivation/reoxygenation (OGD/R)‑induced neuronal death via the adenosine monophosphate‑AMPK/glycogen synthase kinase (GSK)‑3/β/Nrf2/antioxidant response element (ARE) signaling pathways in human neuroblastoma SH‑SY5Y cells. A neuronal injury model was established by depriving SH‑SY5Y cells of oxygen and glucose for 8 h, followed by 24 h of reoxygenation (OGD/R). The results indicated that the OGD/R model exhibited reduced cell viability but increased lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) production and apoptosis. These were accompanied by increased levels of cleaved PARP, cleaved caspase‑9, cleaved caspase‑3, p53, Bax and p21, as well as decreased Bcl‑2 levels. Treatment with petatewalide B was able to strengthen cell viability but reduced LDH release, ROS production and the expression levels of apoptosis‑related proteins. Additionally, treatment with petatewalide B activated AMPK in the OGD/R‑exposed SH‑SY5Y cells and upregulated activation of the downstream transcription factor Nrf2, which accompanied heme oxygenase 1 (HO‑1) and NAD(P)H quinone dehydrogenase 1 (NQO1) expression. Furthermore, silencing AMPK, Nrf2, HO‑1 and NQO1 expression inhibited petatewalide B's protective effect against apoptosis in the OGD/R‑exposed SH‑SY5Y cells. Therefore, petatewalide B protected human neuroblastoma cells against OGD/R‑induced injury by downregulating apoptosis and oxidative stress via upregulation of the AMPK/Nrf2 signaling pathway, suggesting that petatewalide B may be a prospective protector against neuronal injury, having possible therapeutic and medical implications.