Neuropilin-1 promotes cirrhosis of the rodent and human liver by enhancing PDGF/TGF-β signaling in hepatic stellate cells
Sheng Cao, … , Debabrata Mukhopadhyay, Vijay H. Shah
Sheng Cao, … , Debabrata Mukhopadhyay, Vijay H. Shah
Published June 23, 2010
Citation Information: J Clin Invest. 2010;120(7):2379-2394. https://doi.org/10.1172/JCI41203.
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Research Article Hepatology

Neuropilin-1 promotes cirrhosis of the rodent and human liver by enhancing PDGF/TGF-β signaling in hepatic stellate cells

Abstract

PDGF-dependent hepatic stellate cell (HSC) recruitment is an essential step in liver fibrosis and the sinusoidal vascular changes that accompany this process. However, the mechanisms that regulate PDGF signaling remain incompletely defined. Here, we found that in two rat models of liver fibrosis, the axonal guidance molecule neuropilin-1 (NRP-1) was upregulated in activated HSCs, which exhibit the highly motile myofibroblast phenotype. Additionally, NRP-1 colocalized with PDGF-receptor β (PDGFRβ) in HSCs both in the injury models and in human and rat HSC cell lines. In human HSCs, siRNA-mediated knockdown of NRP-1 attenuated PDGF-induced chemotaxis, while NRP-1 overexpression increased cell motility and TGF-β–dependent collagen production. Similarly, mouse HSCs genetically modified to lack NRP-1 displayed reduced motility in response to PDGF treatment. Immunoprecipitation and biochemical binding studies revealed that NRP-1 increased PDGF binding affinity for PDGFRβ-expressing cells and promoted downstream signaling. An NRP-1 neutralizing Ab ameliorated recruitment of HSCs, blocked liver fibrosis in a rat model of liver injury, and also attenuated VEGF responses in cultured liver endothelial cells. In addition, NRP-1 overexpression was observed in human specimens of liver cirrhosis caused by both hepatitis C and steatohepatitis. These studies reveal a role for NRP-1 as a modulator of multiple growth factor targets that regulate liver fibrosis and the vascular changes that accompany it and may have broad implications for liver cirrhosis and myofibroblast biology in a variety of other organ systems and disease conditions.

Authors

Sheng Cao, Usman Yaqoob, Amitava Das, Uday Shergill, Kumaravelu Jagavelu, Robert C. Huebert, Chittaranjan Routray, Soha Abdelmoneim, Meher Vasdev, Edward Leof, Michael Charlton, Ryan J. Watts, Debabrata Mukhopadhyay, Vijay H. Shah

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Figure 4

Migration is reduced in HSCs isolated from mice with genetic deletion of NRP-1.

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Migration is reduced in HSCs isolated from mice with genetic deletion of...
(A) Strategy for the deletion on NRP-1. The targeted allele Nrp1 within exon 2 (Ex-2) is flanked with loxP sites (triangles). Cre-recombinase under the control of the adenovirus CMV promoter mediates the excision of loxP-flanked exon 2. (B) Assessment of Nrp1 deletion using adenovirus Cre in HSCs; Cre-mediated excision on the lox-flanked exon 2 leads to loss of amplified PCR fragment of 200 bp. (C) The migration response to PDGF in HSCs isolated from NRP-1 floxed mice transduced with AdCre is reduced compared with cells transduced with AdGFP as measured by Boyden chamber assay (*P < 0.05 compared with AdGFP).