The role of nerve growth factor and p75 neurotrophin receptor in recovery from liver fibrosis

Rodent hepatic myofibroblasts are susceptible to nerve growth factor-mediated apoptosis through p75 neurotrophin receptor ligation. Hepatic myofibroblast apoptosis is critical to resolution of liver fibrosis. I show that human hepatic myofibroblasts exhibit differential responses to mature and pro-nerve growth factor/p75 neurotrophin receptor-mediated signals. Whilst mature nerve growth factor is proapoptotic, pronerve growth factor protects human hepatic myofibroblasts from serum-deprivation and cycloheximide-induced apoptosis. To define the dominant effect of p75 neurotrophin receptor-mediated events in experimental liver fibrosis I have used a mouse lacking the p75 neurotrophin receptor ligand-binding domain but expressing the intracellular domain. I show that absence of p75 neurotrophin receptor ligand-mediated signals leads to significantly retarded architectural resolution and reduced hepatic myofibroblast loss by apoptosis. Lack of the ligand-competent p75 neurotrophin receptor limits hepatocyte proliferative capacity in vivo without preventing hepatic stellate cell transdifferentiation. Moreover, in recovery from experimental liver fibrosis the fall in pro-nerve growth factor mirrors loss of hepatic myofibroblasts by apoptosis. Thus, nerve growth factor species have a differential effect on hepatic myofibroblast survival, and p75 neurotrophin receptor ligand-mediated events facilitate reduction of liver fibrosis via regulation of hepatic myofibroblast proliferation and apoptosis, and hepatocyte proliferation.

Name dc:type.qualificationname

Ph.D.

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Southampton

Year dc:date.issued

2008

Author dc:creator

• Kendall, Timothy J.

Advisors dc:contributor.advisor

• Iredale, John
• Benyon, Chris