A Fischer rat substrain deficient in dipeptidyl peptidase IV activity makes normal steady-state RNA levels and an altered protein. Use as a liver-cell transplantation model

Abstract

Dipeptidyl peptidase IV (DPPIV) is a serine exoproteinase expressed at high levels in epithelial cells of kidney, liver and small intestine. Recently Watanabe, Kohima & Fujimoto [(1987) Experientia 43, 400-401] and Gossrau et al. [(1990) Histochem. J. 22, 172-173] reported that Fischer 344 rats are deficient in this enzyme. We have examined DPPIV expression in Fischer 344 rats available from U.S. and German suppliers and find that livers of the U.S. Fischer rats, in contrast with their German counterparts, express active DPPIV (D+). Northern analysis of liver RNA showed comparable levels of 3.4 kb and 5.6 kb DPPIV transcripts in both D+ rats from the U.S. and German (D-) rats. Monoclonal antibody (MAb) 236.3 to DPPIV immunoprecipitated at 150 kDa enzymically active (105 kDa, denatured) protein from surface-labelled D+ hepatocytes and reacted with canalicular and sinusoidal membranes (as shown by immunofluorescence microscopy). MAb 236.3 failed to immunoprecipitate a labelled peptide from D- cell extract or to stain D- liver sections. Polyclonal antibody (PAb) specific for DPPIV immunoprecipitated an enzymically active peptide from D+ hepatocyte extracts and a smaller, inactive peptide from D- hepatocyte extracts. Peptide maps of DPPIV immunoprecipitated from D+ extracts with MAb 236.3 and PAb were identical, but differed from that of the D- hepatocyte component recognized by PAb. The molecular basis of the DPPIV deficiency in the D- rats thus appears to be the translation of an enzymically inactive protein missing the epitope recognized by MAb 236.3. We have exploited these D- rats as hosts for syngeneic transplantation of liver cells from D+ Fischer rats. DPPIV expression is stable in the transplanted cells and allows them to be readily distinguished from the surrounding D- tissue.

Differentiation of pancreatic epithelial progenitor cells into hepatocytes following transplantation into rat liver

“…This unique pattern of expression is similar to that observed with ATPase, a classical marker of the hepatocyte bile canaliculus (20). A mutant strain of F344 rats has been identified in which DPPIV enzyme activity is not expressed (21), and a monoclonal antibody, Mab 236.3, which recognizes the normal but not the mutant DPPIV protein, has also been raised (21). In this study, we simultaneously detected both DPPIV and ATPase by histochemical methods (22) to identify and characterize transplanted DPPIV ϩ pancreatic epithelial cells in the DPPIV Ϫ recipient liver and their relationship to endogenous hepatocytes.…”

Dipeptidyl Peptidase IV Inhibition Improves Impaired Glucose Tolerance in High-Fat Diet-Fed Rats: Study Using a Fischer 344 Rat Substrain Deficient in Its Enzyme Activity

“…Japanese F344 rats have been shown to lack the enzyme activity of DPP-IV (18). DPP-IV(-) rats contain mRNA transcripts for DPP-IV, but levels of DPP-IV protein are reduced due to translation of abnormal isoforms that fail to be processed to the biologically active mature glycosylated enzyme (19,20). However, other peptidases such as aminopeptidase, neutral endopeptidase, and gamma-glutamyl transpeptidase are intact in DPP-IV(-) F344 rats (18).…”

“…DPP-IV deficient (-) rats contain mRNA transcripts for DPP-IV but reduced levels of DPP-IV protein due to the translation of abnormal isoforms that fail to be processed to the biologically active mature glycosylated enzyme (19,20). These rats have reduced N-terminal degradation of GLP-1 by DPP-IV following infusion of GLP-1 (9), and have been used in studies on the role of DPP-IV/ CD26 in the immune system including T-cell activation, transplantation, and arthritis (21 -24).…”

Functional Characterization of Serum-Free Cultured Rat Hepatocytes for Downstream Transplantation Applications

“…Therefore, rat hepatocytes were cultured for 4 or 7 days and subsequently transplanted into the CD26-positive hepatocytes grew out from the periportal regions towards the central veins. Seven weeks after livers of CD26-deficient Fischer 344 (F344) rats to localize CD26-positive transplanted cells in the negative transplantation, larger clusters of donor-derived cells comprising up to 200 cells were clearly visible (insets recipient background (33). Prior to transplantation, host animals were treated with retrorsine, a naturally occurin Fig.…”