Apigenin Alleviated High-Fat-Diet-Induced Hepatic Pyroptosis by Mitophagy-ROS-CTSB-NLRP3 Pathway in Mice and AML12 Cells

by Selleckchem | Jun 08 2023

Apigenin is considered the most-known natural flavonoid and is abundant in a wide variety of fruits and vegetables. A high fat diet (HFD) can induce liver injury and hepatocyte death in multiple ways. Pyroptosis is an innovative type of programmed cell death. Moreover, excessive pyroptosis of hepatocytes leads to liver injury. We used HFD to induce liver cell pyroptosis in C57BL/6J mice in this work. After gavage of apigenin, apigenin can significantly reduce the level of lactate dehydrogenase (LDH) in liver tissue ignited by HFD and reduce the levels of NLRP3 (NOD-like receptor family pyrin domain containing 3), the N-terminal domain of GSDMD (GSDMD-N), cleaved-caspase 1, cathepsin B (CTSB), interleukin-1β (IL-1β) and interleukin-18 (IL-18) protein expression and the colocalization of NLRP3 and CTSB and increase the level of lysosomal associated membrane protein-1 (LAMP-1) protein expression, thus alleviating cell pyroptosis. In a further in vitro mechanism study, we find that palmitic acid (PA) can induce pyroptosis in AML12 cells. After adding apigenin, apigenin can clear the damaged mitochondria through mitophagy and reduce the generation of intracellular reactive oxygen species (ROS), thus alleviating CTSB release caused by lysosomal membrane permeabilization (LMP), reducing the LDH release caused by PA and reducing the levels of NLRP3, GSDMD-N, cleaved-caspase 1, CTSB, IL-1β, and IL-18 protein expression. By adding the mitophagy inhibitor cyclosporin A (CsA), LC3-siRNA, the CTSB inhibitor CA-074 methyl ester (CA-074 Me), and the NLRP3 inhibitor MCC950, the aforementioned results were further confirmed. Therefore, our results show that HFD-fed and PA can damage mitochondria, promote the production of intracellular ROS, enhance the lysosomal membrane permeabilization (LMP), and cause the leakage of CTSB, thus activating the NLRP3 inflammatory body and inducing pyroptosis in C57BL/6J mice and AML12 cells, while apigenin alleviates this phenomenon through the mitophagy-ROS-CTSB-NLRP3 pathway.

Comments:

This passage describes a study on the effects of apigenin, a natural flavonoid found in fruits and vegetables, on liver injury caused by a high fat diet (HFD) in mice and in vitro cell cultures. The study found that HFD and palmitic acid (PA) induced pyroptosis, a type of programmed cell death, in liver cells through the activation of the NLRP3 inflammatory body. Apigenin was found to alleviate liver cell pyroptosis by reducing the levels of lactate dehydrogenase (LDH), NLRP3, the N-terminal domain of GSDMD (GSDMD-N), cleaved-caspase 1, cathepsin B (CTSB), interleukin-1β (IL-1β) and interleukin-18 (IL-18) protein expression, and the colocalization of NLRP3 and CTSB, while increasing the level of lysosomal associated membrane protein-1 (LAMP-1) protein expression.

Further in vitro studies showed that apigenin cleared damaged mitochondria through mitophagy, reduced the generation of intracellular reactive oxygen species (ROS), and alleviated CTSB release caused by lysosomal membrane permeabilization (LMP), thereby reducing LDH release and the levels of NLRP3, GSDMD-N, cleaved-caspase 1, CTSB, IL-1β, and IL-18 protein expression. These effects were further confirmed using the mitophagy inhibitor cyclosporin A (CsA), LC3-siRNA, the CTSB inhibitor CA-074 methyl ester (CA-074 Me), and the NLRP3 inhibitor MCC950. Overall, the study suggests that HFD and PA induce liver injury through pyroptosis and that apigenin alleviates this phenomenon through the mitophagy-ROS-CTSB-NLRP3 pathway.