Improving engraftment for cell therapy in cholangiopathies

Abstract

The cholangiopathies are a group of conditions associated with injury to the bile ducts in the liver. Recent murine studies have demonstrated the potential of hepatic progenitor cells (HPC) as cell therapy for the treatment of cholangiopathies.

The biliary engraftment of HPC in the Krt19CreᴱᴿMdm2 ᶠˡ/ᶠˡ Rag2⁻/⁻ Il2rg⁻/⁻ mouse model of cholangiopathy is poor at present, this could limit the progression of this therapy to the clinic. The aim of this thesis is to improve biliary engraftment of human HPC in the Krt19CreᴱᴿMdm2 ᶠˡ/ᶠˡ Rag2⁻/⁻ Il2rg⁻/⁻ model of cholangiopathy.

The identification of specific markers in the biliary system which were upregulated in injury was made. Using this information, markers were targeted with receptors upregulated in the plasma membrane of transplanted human HPC.

To identify a marker, the expression of biliary specific proteins SCTR, CD44, TFF2, CCL2, CXCL1 and CXCL2 was investigated in the Krt19CreᴱᴿMdm2 ᶠˡ/ᶠˡ Rag2⁻/⁻ Il2rg⁻/⁻ model. CXCL2 was upregulated in injury and had higher expression in the biliary ducts when compared with hepatocytes. A proteomic analysis was also performed which did not yield additional targets, however it did identify two novel biliary specific proteins in ANXAV and MYH14.

The receptor for CXCL2 is CXCR2. In this thesis we demonstrated CXCR2 is not normally expressed in HPC. It was shown that HPC could be transduced to express CXCR2 and GFP using a lentivirus construct.

CXCR2 and GFP expressing HPC were transplanted into the Krt19CreᴱᴿMdm2 ᶠˡ/ᶠˡ Rag2⁻/⁻ Il2rg⁻/⁻ model of cholangiopathy. Transplanted cells were demonstrated to engraft in close proximity to the bile ducts. When compared with GFP only HPC, CXCR2 GFP HPC were found adjacent to fewer ducts but in larger numbers. The potential for developing a homing system for transplantation of HPC in the cholangiopathies is demonstrated in this thesis.