Compositions and Methods for Treating Pathological Calcification and Ossification

Abstract

The present invention includes compositions and methods for treating disease and disorders associated with pathological calcification or pathological ossification by modulating the level or activity of NPP1 or a mutant thereof, or a mutant NPP4 modified to exhibit ATP hydrolase activity similar to the hydrolase activity of NPP1.

What is claimed is: 
     
         1 . An autonomously replicating or an integrative mammalian cell vector comprising a recombinant nucleic acid encoding an ecto-nucleotide pyrophosphate/phosphodiesterase-1 (ENPP1) precursor polypeptide comprising an ENPP1 catalytic domain, wherein the precursor polypeptide comprises a transmembrane domain and lacks 4 to 20 sequential aspartic acid residues. 
     
     
         2 . The vector of  claim 1 , wherein the vector comprises a plasmid or virus. 
     
     
         3 . The vector of  claim 1 , wherein the transmembrane domain comprises an ENPP1 or ENPP2 transmembrane domain. 
     
     
         4 . The vector of  claim 1 , wherein the vector comprises a mammalian cell expression vector. 
     
     
         5 . A cell comprising the vector of  claim 1 . 
     
     
         6 . The cell of  claim 5 , wherein the cell is a mammalian cell. 
     
     
         7 . A method of expressing soluble ecto-nucleotide pyrophosphate/phosphodiesterase-1 (ENPP1) in a cell, the method comprising contacting the cell with an autonomously replicating or an integrative mammalian cell vector comprising a recombinant nucleic acid encoding an ENPP1 precursor polypeptide comprising an ENPP1 catalytic domain, wherein the precursor polypeptide comprises a transmembrane domain and lacks 4-20 sequential aspartic acid residues, whereby the ENPP1 precursor polypeptide is expressed in the cell. 
     
     
         8 . The method of  claim 7 , wherein the transmembrane domain comprises an ENPP1 transmembrane domain. 
     
     
         9 . The method of  claim 7 , wherein the transmembrane domain comprises a signal sequence and wherein soluble ENPP1 is secreted from the cell. 
     
     
         10 . The method of  claim 7 , wherein the signal sequence is from an ENPP2 transmembrane domain and wherein soluble ENPP1 is secreted from the cell. 
     
     
         11 . The method of  claim 9 , wherein the precursor polypeptide comprises an IgG Fc domain and wherein the soluble ENPP1 comprises the IgG Fc domain. 
     
     
         12 . The method of  claim 9 , further comprising the step of purifying the soluble ENPP1 from the cell to provide a purified soluble ENPP1. 
     
     
         13 . The method of  claim 12 , wherein the purified soluble ENPP1 has a purity of greater than 95%. 
     
     
         14 . The method of  claim 7 , wherein the cell is present in a human subject, and wherein the cell is contacted with the vector by administering the vector to the subject. 
     
     
         15 . The method of  claim 14 , wherein the vector is a viral vector.