Caspase-2 and p75 neurotrophin receptor (p75NTR) are involved in the regulation of SREBP and lipid genes in hepatocyte cells

Cell Death Dis. 2019 Jul 11;10(7):537. doi: 10.1038/s41419-019-1758-z.

Abstract

Lipid-induced toxicity is part of several human diseases, but the mechanisms involved are not fully understood. Fatty liver is characterized by the expression of different growth and tissue factors. The neurotrophin, nerve growth factor (NGF) and its pro-form, pro-NGF, are present in fatty liver together with p75 neurotrophin receptor (p75NTR). Stimulation of human Huh7 hepatocyte cells with NGF and pro-NGF induced Sterol-regulator-element-binding protein-2 (SREBP2) activation and increased Low-Density Lipoprotein Receptor (LDLR) expression. We observed that phosphorylation of caspase-2 by p38 MAPK was essential for this regulation involving a caspase-3-mediated cleavage of SREBP2. RNA sequencing showed that several genes involved in lipid metabolism were altered in p75NTR-deficient mouse liver. The same lipogenic genes were downregulated in p75NTR gene-engineered human Huh7 cells and reciprocally upregulated by stimulation of p75NTRs. In the knock-out mice the serum cholesterol and triglyceride levels were reduced, suggesting a physiological role of p75NTRs in whole-body lipid metabolism. Taken together, this study shows that p75NTR signaling influences a network of genes involved in lipid metabolism in liver and hepatocyte cells. Modulation of p75NTR signaling may be a target to consider in various metabolic disorders accompanied by increased lipid accumulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caspase 2 / chemistry
  • Caspase 2 / genetics
  • Caspase 2 / metabolism*
  • Fatty Liver / genetics
  • Fatty Liver / metabolism*
  • Gene Expression Regulation / genetics
  • Hepatocytes / drug effects
  • Hepatocytes / metabolism*
  • Humans
  • Lipid Metabolism / drug effects
  • Lipid Metabolism / genetics*
  • Mice
  • Mice, Knockout
  • Nerve Growth Factor / metabolism
  • Nerve Growth Factor / pharmacology
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Phosphorylation
  • Receptors, LDL / genetics
  • Receptors, LDL / metabolism
  • Receptors, Nerve Growth Factor / genetics
  • Receptors, Nerve Growth Factor / metabolism*
  • Signal Transduction / genetics
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • NGFR protein, human
  • Nerve Tissue Proteins
  • Receptors, LDL
  • Receptors, Nerve Growth Factor
  • Sterol Regulatory Element Binding Protein 1
  • Ngfr protein, mouse
  • Nerve Growth Factor
  • p38 Mitogen-Activated Protein Kinases
  • Caspase 2