Soluble ENPP1 proteins and uses thereof
In certain aspects, the present invention provides novel soluble ENPP1 or ENPP3 polypeptides, as well as compositions and methods for using those variants to treat an indication associated an ENPP1 or ENPP3 deficiency. The compositions and methods provided herein are useful in treating diseases associated with an ENPP1 or ENPP3 deficiency such as pathological calcification or pathological ossification.
1 . A soluble ectonucleotide pyrophosphatase/phosphodiesterase (ENPP1) polypeptide that lacks both Somatomedin B (SMB) domain 1 and SMB domain 2 of ENPP1, and wherein the soluble ENPP1 polypeptide is at least 90% identical to the amino acid sequence of SEQ ID NO: 121 and the catalytic domain of the ENPP1 portion of the soluble ENPP1 polypeptide comprises a 1332T substitution and the Fc domain comprises a triple mutation (M252Y, S254T, T256E).
2 . The soluble ENPP1 polypeptide of claim 1 , wherein the soluble ENPP1 polypeptide comprises the amino acid sequence of SEQ ID NO: 121.
3 . The soluble ENPP1 polypeptide of claim 1 , wherein the polypeptide has reduced ability to homodimerize as compared to the corresponding wild-type soluble ENPP1; and/or
wherein the polypeptide has reduced affinity for the human insulin receptor (IR) as compared to the corresponding wild-type soluble ENPP1 polypeptide.
4 . The soluble ENPP1 polypeptide of claim 1 , wherein the ENPP1 polypeptide demonstrates greater proteolytic resistance to a protease than the corresponding wild-type soluble ENPP1 polypeptide.
5 . The soluble ENPP1 polypeptide of claim 1 , wherein the greater proteolytic resistance of the ENPP1 polypeptide provides a homogenous composition with protein purity increased by about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, or 300% as compared to a corresponding wild-type soluble ENPP1 polypeptide; and/or
wherein the greater proteolytic resistance of the ENPP1 polypeptide decreases protein cleavage by 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 225%, 250%, 275%, or 300% as compared to the corresponding wild-type soluble ENPP1 polypeptide; and/or
wherein the protease is trypsin or trypsin-like proteases.
6 . The soluble ENPP1 polypeptide according to claim 1 , wherein the soluble ENPP1 polypeptide further comprises a heterologous moiety and wherein the heterologous moiety is selected from the group consisting of a glycosylated amino acid, a PEGylated amino acid, a farnesylated amino acid, an acetylated amino acid, a biotinylated amino acid, and a lipid moiety.