Potential treatment of hypoparathyroidism with recombinant plasmids encoding preproparathyroid hormone.

Hypoparathyroidism cannot be cured by oral or intravenous calcium supplements. Using molecular biology techniques to induce the production of PTH is an ideal option to treat hypoparathyroidism. In this study, we established a recombinant plasmid encoding a mutant preproPTH with a skeletal muscle creatine kinase promoter (pCKM-mPTH). The sequence of the chimeric pCKM-mPTH gene was fully consistent with the DNA sequence reported previously and the site-directed mutagenesis was completed. Overlapping and nested PCR showed that PTH was highly expressed in and secreted from skeletal muscle cells transfected with the pCKM-mPTH plasmid: the PTH concentration in the culture medium 24 h after transfection was 26.37 pg/l. In the rat hypoparathyroidism model, serum PTH level significantly increased after injection with the pCKM-mPTH plasmid, compared with control groups (p<0.01). The effect lasted for about 30 days. Our results indicated that the recombinant mutant pCKM-mPTH plasmid was successfully constructed and was highly expressed in skeletal muscle cells. In vivo, the plasmid was introduced successfully into rat muscles and could express PTH for a decent period of time.