Supplementation of L-aspartate corrects MASLD and MASH in mice by inhibiting platelet-hepatocyte interaction-mediated mitochondrial fragmentation via the ATP-P2X7-NEK7-DRP1 axis.

Plasma and liver L-aspartate levels were decreased in MASLD and negatively correlated with disease severity in both mice and humans.

• L-aspartate levels were measured in both plasma and liver tissue of MASLD mouse models and human subjects.
• A negative correlation was observed between L-aspartate levels and the severity of MASLD.
• This reduction in L-aspartate was observed across both MASLD and its severe form MASH.

L-aspartate supplementation reversed the manifestations of both MASLD and MASH in mice.

• L-aspartate treatment corrected hepatic steatosis and steatohepatitis in mouse models.
• Improvements were correlated with enhancements in hepatic mitochondrial quality and oxidation.
• The reversal was observed across multiple markers of MASLD and MASH pathology.

Joint transcriptome and metabolomics analyses revealed that cGMP metabolism and platelet activation were highly annotated pathways following a single L-aspartate treatment.

• The combined transcriptomic and metabolomic approach identified cGMP as a highly annotated metabolite after L-aspartate treatment.
• Platelet activation was among the most significantly enriched pathways identified in the analysis.
• These findings directed subsequent mechanistic investigations toward the platelet-hepatocyte interaction axis.

L-aspartate treatment increased cGMP levels in platelets and blocked platelet activation and aggregation.

• L-aspartate supplementation elevated intracellular cGMP concentrations specifically in platelets.
• Increased cGMP in platelets was associated with suppression of platelet activation and aggregation.
• The increase in platelet cGMP was correlated with reductions in plasma levels of ADP and thrombin, which are inducers of platelet activation.
• Blockade of platelet activation suppressed activated platelet-derived ATP secretion.

Activated platelet-derived ATP hyperactivated the P2X7-NEK7-DRP1 axis in hepatocytes, driving mitochondrial fragmentation and lipid accumulation.

• ATP released from activated platelets acted on hepatocyte P2X7 receptors to hyperactivate the P2X7-NEK7-DRP1 signaling axis.
• Hyperactivation of this axis caused mitochondrial fragmentation in hepatocytes.
• L-aspartate addition reversed ATP-induced increases in oleic acid-induced mitochondrial fragmentation and lipid accumulation in hepatocytes.
• NEK7 knockdown corrected oleic acid + ATP-induced exacerbations of mitochondrial fragmentation and lipid accumulation.

Treatment with the antiplatelet agent aspirin or the P2X7 inhibitor ameliorated MASLD in mice and corrected oleic acid + ATP-induced mitochondrial fragmentation and lipid accumulation in hepatocytes.

• Aspirin, as an antiplatelet agent, corrected oleic acid + ATP-induced exacerbations of mitochondrial fragmentation and lipid accumulation in hepatocytes.
• A P2X7 inhibitor similarly reversed the exacerbations of mitochondrial fragmentation and lipid accumulation.
• Both aspirin and the P2X7 inhibitor ameliorated MASLD in mouse models.
• These results confirm that the platelet-P2X7-NEK7-DRP1 pathway is a therapeutically actionable axis in MASLD.

Activated platelet-mediated mitochondrial fragmentation in hepatocytes was identified as a pivotal driving force for MASLD and MASH.

• The study established a mechanistic link between platelet activation, ATP secretion, and hepatocyte mitochondrial fragmentation.
• Mitochondrial fragmentation was associated with lipid accumulation and impaired mitochondrial quality in the liver.
• Blocking platelet activation at multiple levels (L-aspartate, aspirin, P2X7 inhibition, NEK7 knockdown) consistently ameliorated disease manifestations.
• The authors conclude that blocking platelet activation underlies the therapeutic potential and metabolic regulation of L-aspartate against MASLD and MASH.