Autophagy and Lipid Metabolism in Liver Disease

Liver disease associated with lipid accumulation, notably non-alcoholic fatty liver disease (NAFLD), arises when the balance of lipid uptake, synthesis, storage and degradation is disrupted. Autophagy, the process by which cells degrade and recycle their own components, plays a central role in hepatic lipid homeostasis. A specialised form of autophagy, lipophagy, targets lipid droplets for lysosomal degradation and thereby limits steatosis. Dysregulation of autophagic flux, often linked to impaired lysosomal acidification and aberrant nutrient‐sensing signalling, exacerbates lipid deposition, mitochondrial dysfunction and endoplasmic reticulum stress in hepatocytes. As NAFLD progresses to non-alcoholic steatohepatitis (NASH), fibrosis and even hepatocellular carcinoma, defects in both bulk autophagy and selective removal of lipid stores contribute to inflammation, cell death and metabolic decline. Recent advances have elucidated the molecular regulators of hepatic autophagy—chief among them mTOR and AMPK—as well as cross-talk between adipose tissue, muscle and liver mediated by endocrine factors such as FGF21. Understanding this interplay has revealed new therapeutic targets to restore autophagic clearance of lipids, improve insulin sensitivity and reverse steatosis in preclinical models and early human studies.

Research from Nature Portfolio

Innovative lysosome-targeting nanoparticles have been developed to restore acidic pH within hepatic lysosomes of high-fat diet models. By selectively activating within dysfunctional lysosomes, these biodegradable particles re-acidify the organelle, rescue autophagic flux and mitochondrial performance, and reverse fasting hyperglycaemia and steatosis, suggesting a first-in-class autophagy-based approach to NAFLD treatment. Separately, the antidiabetic agent pioglitazone has been shown to alleviate hepatic steatosis by coordinating cytosolic lipolysis, β-oxidation and autophagy. In murine and cellular models, pioglitazone enhances expression of lipolytic and autophagy-related proteins via PPARα/γ-dependent pathways, facilitating lipid droplet clearance and improving insulin sensitivity. These studies highlight both novel delivery systems and repurposed drugs that target autophagic mechanisms to combat liver lipid overload.

Autophagy and Lipid Metabolism in Liver Disease publication trend

The graph below shows the total number of articles in autophagy and lipid metabolism in liver disease across all publications each year (not limited to Nature Index journals).

Technical terms

Autophagy: A cellular degradation pathway in which cytoplasmic components are delivered to lysosomes for recycling.

Lipophagy: Selective autophagic degradation of intracellular lipid droplets within lysosomes.

Lysosomal acidification: The process by which lysosomal pH is maintained at acidic levels to enable hydrolase activity.

mTOR pathway: A nutrient-sensing kinase cascade that inhibits autophagy when nutrients are abundant.

AMPK: An energy sensor kinase activated by low cellular ATP levels that promotes autophagy and lipid oxidation.

Hepatic steatosis: Excessive accumulation of triglycerides within liver cells.

Non-alcoholic fatty liver disease (NAFLD): A spectrum of liver disorders characterised by lipid accumulation in the absence of significant alcohol intake.

Non-alcoholic steatohepatitis (NASH): An advanced form of NAFLD marked by inflammation, hepatocellular injury and varying degrees of fibrosis.

References

1. Restoration of lysosomal acidification rescues autophagy and metabolic dysfunction in non-alcoholic fatty liver disease. Nature Communications (2023).
2. Exercise and dietary intervention ameliorate high-fat diet-induced NAFLD and liver aging by inducing lipophagy. Redox Biology (2020).
3. Impaired autophagic flux is associated with increased endoplasmic reticulum stress during the development of NAFLD. Cell Death & Disease (2014).
4. Autophagy and Non‐Alcoholic Fatty Liver Disease. BioMed Research International (2014).
5. Lipophagy Impairment Is Associated With Disease Progression in NAFLD. Frontiers in Physiology (2020).
6. The Role of Lipophagy in the Development and Treatment of Non-Alcoholic Fatty Liver Disease. Frontiers in Endocrinology (2021).
7. Pioglitazone Enhances Cytosolic Lipolysis, β-oxidation and Autophagy to Ameliorate Hepatic Steatosis. Scientific Reports (2017).