Microcystin-LR promotes necroptosis in primary mouse hepatocytes by overproducing reactive oxygen species

Area of Science:

• Hepatotoxicity
• Cell Death Mechanisms
• Cyanotoxin Research

Background:

• Microcystin-LR (MC-LR) is a cyanobacterial toxin known for causing liver damage.
• MC-LR-induced apoptosis is a well-documented mechanism of liver injury.
• The existence and mechanisms of other programmed cell death pathways induced by MC-LR remain largely unexplored.

Purpose of the Study:

• To investigate alternative programmed cell death pathways induced by MC-LR in primary mouse hepatocytes.
• To elucidate the underlying molecular mechanisms, particularly the role of reactive oxygen species (ROS).
• To identify novel therapeutic targets for MC-LR-induced liver injury.

Main Methods:

• Primary mouse hepatocytes were treated with MC-LR.
• Cell death pathways were assessed using annexin V/PI staining, flow cytometry, and PI staining.
• Cell viability was measured by CCK8 assay.
• Plasma membrane integrity was evaluated by lactate dehydrogenase release.
• ROS levels were quantified using the carboxy-H2DCFDA probe.
• Western blot analysis was performed to examine protein expression related to apoptosis and necroptosis.

Main Results:

• MC-LR induced significant necroptosis, characterized by increased annexin V/PI double-positive cells and diffuse PI-stained nuclei.
• MC-LR treatment upregulated key proteins involved in both necroptosis and apoptosis.
• MC-LR caused ROS overproduction by altering the expression and activity of SOD1, MAOA, NOX4, and GPX1.
• Plasma membrane damage and cell death were observed in MC-LR-exposed hepatocytes.

Conclusions:

• MC-LR induces necroptosis in primary mouse hepatocytes via ROS overactivation.
• This study uncovers a novel mechanism of MC-LR-mediated liver injury.
• Targeting ROS pathways presents a potential therapeutic strategy for MC-LR poisoning.