Core Concepts
Hepatocyte-specific deficiency of RIPK1 sensitizes the liver to metabolic challenges, such as short-term fasting or high-fat diet, leading to acute liver injury, hepatocyte apoptosis, inflammation, and compensatory proliferation.
Abstract
This study investigated the physiological role of RIPK1 in the liver and found that hepatocyte-specific RIPK1 deficiency (Ripk1Δhep mice) sensitized the liver to metabolic challenges, such as short-term fasting or high-fat diet feeding.
Key findings:
- Short-term fasting induced significant liver injury, hepatocyte apoptosis, and inflammation in Ripk1Δhep mice, but not in control mice.
- Transcriptomic analysis revealed that fasting triggered an inflammatory response in Ripk1Δhep mice, with upregulated expression of inflammation and immune cell recruitment-associated genes.
- Single-cell RNA sequencing confirmed the increased recruitment of macrophages to the liver in Ripk1Δhep mice during fasting.
- Mechanistically, endoplasmic reticulum (ER) stress was involved in fasting-induced liver injury in Ripk1Δhep mice, and inhibition of ER stress rescued the liver phenotype.
- Similar effects were observed in Ripk1Δhep mice subjected to short-term high-fat diet feeding, suggesting that hepatocyte RIPK1 is essential for maintaining liver homeostasis during metabolic disturbances.
Overall, this study reveals a critical role of RIPK1 in preserving liver homeostasis during metabolic challenges and provides insights into the interplay between cell death, inflammation, and liver adaptation to metabolic stress.
Stats
Serum alanine amino-transferase (ALT) levels were significantly increased in Ripk1Δhep mice compared to control mice after short-term fasting.
Serum aspartate amino-transferase (AST) levels were significantly increased in Ripk1Δhep mice compared to control mice after short-term fasting.
The number of TUNEL-positive cells (apoptotic cells) in the liver was significantly higher in Ripk1Δhep mice compared to control mice after short-term fasting.
The number of cleaved caspase-3-positive cells (apoptotic cells) in the liver was significantly higher in Ripk1Δhep mice compared to control mice after short-term fasting.
Quotes
"Our results demonstrated that hepatocyte-specific deficiency of RIPK1 sensitized the liver to short-term fasting-induced liver injury and hepatocyte apoptosis in both male and female mice."
"Transcriptomic analysis revealed that short-term fasting oriented the hepatic microenvironment into an inflammatory state in Ripk1Δhep mice, with upregulated expression of inflammation and immune cell recruitment-associated genes."
"Single-cell RNA sequencing further confirmed the altered cellular composition in the liver of Ripk1Δhep mice during fasting, highlighting the increased recruitment of macrophages to the liver."