GSE160984
Lipin 1 regulates mRNA splicing in fasting and feeding in mouse liver
The lipin phosphatidate phosphatase (PAP) enzymes (lipin 1, lipin 2, and lipin 3) catalyze a step in triglyceride and phospholipid biosynthesis, and genetic lipin deficiencies cause human disease that is triggered by metabolic stress, such as fasting. We assessed the protein interactome of lipins 1, 2, and 3 in hepatocytes, and identified unique protein associations between lipin 1 and U2 mRNA spliceosome components. Lpin1–/– mouse liver exhibited aberrant mRNA splicing in the fasted state, including mRNAs involved in mRNA processing and liver maturation. Aberrant splicing could be induced in cultured hepatocytes by lipin 1 knockdown or elevated phosphatidic acid levels, suggesting a role for lipin 1 PAP activity in splicing fidelity. Refeeding Lpin1–/– animals after fasting largely restored mRNA splicing fidelity. Reduced levels of ESRP2 splicing factor exclusively in the fasted state of Lpin1–/– liver was associated with widespread aberrant exon inclusion.  These findings connect lipid homeostasis with mRNA splicing, and identify aberrant mRNA splicing in lipin 1 deficiency as a potential contributor to disease symptoms triggered by fasting. Overall design: Mouse liver RNA was isolated from fasting and feeding conditions for RNA sequencing