Calcified Tissue International

, Volume 88, Issue 6, pp 511–520

Monthly Administration of a Novel PTH-Collagen Binding Domain Fusion Protein is Anabolic in Mice

  • Tulasi Ponnapakkam
  • R. Katikaneni
  • E. Miller
  • A. Ponnapakkam
  • S. Hirofumi
  • S. Miyata
  • L. J. Suva
  • J. Sakon
  • O. Matsushita
  • R. C. Gensure
Original Research

DOI: 10.1007/s00223-011-9485-1

Cite this article as:
Ponnapakkam, T., Katikaneni, R., Miller, E. et al. Calcif Tissue Int (2011) 88: 511. doi:10.1007/s00223-011-9485-1

Abstract

We synthesized fusion proteins of parathyroid hormone (PTH) (1–33) and the collagen binding domain of ColH (CBD) and tested them for anabolic bone activity in mice. Two fusion proteins were synthesized, linking the carboxy terminus of PTH(1–33) either directly to the amino terminal of the CBD or to the CBD through an adjacent ColH domain (PTH-PKD-CBD). Both PTH-CBD and PTH-PKD-CBD increased cAMP accumulation in cells stably transfected with the PTH/PTHrP receptor, and both peptides bound to type 1 collagen in flow-through assays. Distribution studies indicated that the PTH-CBD was concentrated in the bone and skin, tissues with abundant collagen and blood flow. Administration of 320 μg/kg PTH-CBD either weekly (for 8 weeks) or monthly (for 6 months) to 7-week-old C57BL/6J mice resulted in a sustained increase in bone mineral density (BMD) (15% for weekly studies, 13% for monthly studies; P < 0.05). PTH-PKD-CBD showed only 5% increases in BMD after weekly administration, and, as expected, neither weekly nor monthly PTH(1–34) affected BMD. PTH-CBD increased serum alkaline phosphatase levels. Importantly, there were no significant increases in serum calcium observed. Collectively, the data suggest that PTH-CBD has a sustained anabolic effect in bone with either weekly or monthly administration. This approach of targeted delivery of PTH to bone may show promise for the treatment of disorders of low bone mass, such as postmenopausal osteoporosis.

Keywords

Bone mineral densityMiceOsteoporosisParathyroid hormoneCollagen binding domainCollagenase

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Tulasi Ponnapakkam
    • 1
    • 2
  • R. Katikaneni
    • 1
    • 2
  • E. Miller
    • 3
  • A. Ponnapakkam
    • 3
  • S. Hirofumi
    • 4
  • S. Miyata
    • 5
  • L. J. Suva
    • 6
  • J. Sakon
    • 7
  • O. Matsushita
    • 8
  • R. C. Gensure
    • 1
    • 2
  1. 1.Pediatric EndocrinologyChildren’s Hospital at MontefioreBronxUSA
  2. 2.Albert Einstein College of MedicineBronxUSA
  3. 3.Pediatric Endocrinology Research LaboratoryOchsner Clinic FoundationNew OrleansUSA
  4. 4.Division of Radioisotope Research, Life Science Research CenterKagawa UniversityKagawaJapan
  5. 5.Department of MicrobiologyUniversity of KagawaTakamatsuJapan
  6. 6.Department of Orthopaedic Surgery, Center for Orthopaedic ResearchUniversity of Arkansas for Medical SciencesLittle RockUSA
  7. 7.Department of Chemistry and BiochemistryUniversity of ArkansasFayettevilleUSA
  8. 8.Department of Microbiology and ParasitologyKitasato, University Medical SchoolKanagawaJapan