Bone Affinity of a Bisphosphonate-Conjugated Protein in Vivo

Uludağ, Hasan; Gao, Tiejun; Wohl, Gregory R.; Kantoci, Darko; Zernicke, Ronald F.

doi:10.1021/bp000066y

Cited by 38 publications

(31 citation statements)

References 8 publications

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“…The higher TE values were due to higher clearance of the control proteins from the bone sites. Such an observation was previously noted by us when native and aminoBP-conjugated BSA was directly injected into tibia (13). This observation is also analogous to observations reported by other investigators who prepared BP conjugates of 17 -estradiol; unmodified 17 -estradiol was cleared from bones within hours of IV injection but the BP conjugate of 17 -estradiol had a bone half-life of 13.5 days (22).…”

Section: Discussionsupporting

confidence: 88%

“…The mineral affinity was shown to be directly correlated with the extent of aminoBP conjugation, and it was retained in a protein-rich medium such as serum (12). The conjugates exhibited a high affinity to bone in vivo after intraosseous (tibia) injection in rats (13). The superior bone affinity was shown in normal as well as osteopenic, ovariectomized rats and resulted in 8-to 12-fold increased concentration of the protein at bony sites (13).…”

Section: Introductionmentioning

confidence: 96%

“…The conjugates exhibited a high affinity to bone in vivo after intraosseous (tibia) injection in rats (13). The superior bone affinity was shown in normal as well as osteopenic, ovariectomized rats and resulted in 8-to 12-fold increased concentration of the protein at bony sites (13). A critical issue, namely, the ability of the systemically administered conjugates to "seek" bone, had not been addressed before.…”

Section: Introductionmentioning

confidence: 99%

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Targeting Systemically Administered Proteins to Bone by Bisphosphonate Conjugation

Uludağ

Yang

2002

Biotechnology Progress

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To develop a methodology for bone-specific delivery of proteins, a bone-seeking aminobisphosphonate (aminoBP) was previously conjugated to a model protein, bovine serum albumin (BSA). The conjugates were shown to exhibit a high affinity to bone in vitro and in vivo. This study was conducted to determine whether the systemic delivery of proteins to bone can be increased by aminoBP conjugation. Two model proteins used for this study were BSA and lysozyme (LYZ). For each protein, an unmodified (i.e., control) and aminoBP-conjugated protein were (125)I-labeled and injected into rats, and the organ delivery of the proteins were determined. Intravenous (IV) injection of aminoBP-BSA resulted in a 2.0- to 3.7-fold increased delivery to bones as compared to the control protein in young rats. In osteopenic, ovariectomized rats, aminoBP conjugation enhanced the bone delivery of BSA by 2.2- to 7.5-fold. A 3.7- to 5.6-fold increased delivery was also observed for LYZ after IV injection in normal rats. In addition to IV route of administration, subcutaneous injection was also effective in delivering a higher amount of aminoBP-conjugated proteins to bone. We conclude that conjugating bone-seeking aminoBPs to proteins improved their delivery to mineralized tissues. The proposed targeting approach has the potential to improve the efficacy of recombinant proteins capable of stimulating bone formation by enhancing their localization to bones.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Targeting Systemically Administered Proteins to Bone by Bisphosphonate Conjugation

Uludağ

Yang

2002

Biotechnology Progress

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“…9 This level of substitution was also sufficient for intraosseously injected BSA, which exhibited a ϳ 10-fold increased bone binding as compared to unmodified BSA. 19 For bone targeting purposes, conjugates with ϳ 11 aminoBP/BSA were capable of seeking bone tissue after systemic administration due to their inherent affinity to the bone mineral hydroxyapatite. 6 Accordingly, the reaction conditions utilizing the SPDP and thiolBP were able to yield the necessary extent of BP substitution on the target protein.…”

Section: Control Of Bp Conjugation To Bsamentioning

confidence: 99%

Imparting mineral affinity to proteins with thiol–labile disulfide linkages

Bansal

Wright

Zhang

et al. 2005

J Biomedical Materials Res

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Chemical conjugation of bisphosphonates (BPs) to proteins is an effective means to enhance binding of proteins to mineral-containing biomaterials. BPs linked to proteins with reversible (i.e., cleavable) linkages were considered desirable over the conjugates linked with stable linkages because cleavable linkages allow protein release in free form from the mineral-containing biomaterials. To explore the feasibility of creating cleavable BP-protein conjugates, an amine- and a thiol-containing BP were conjugated to the model protein Bovine Serum Albumin (BSA) with N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP), which resulted in disulfide-linked BP-BSA conjugates. Although disulfide-linked conjugates were stable under aqueous conditions, the conjugates in solution were readily cleaved in the presence of physiological concentrations (approximately 0.3 mM) of the thiol compound, cysteine. The imparted mineral affinity as a result of BP conjugation, as assessed by hydroxyapatite (HA) binding in vitro, was lost upon cleavage of the disulfide-linked BP. The conjugates bound to HA were also cleavable with cysteine, but their cleavage rate was significantly reduced as compared to the conjugates in solution. In conclusion, disulfide-linked BP conjugates were shown to be readily cleavable by the amino acid cysteine and this resulted in the loss of imparted mineral affinity of the proteins. The proposed approach will be useful for modulating in vivo delivery of proteins implanted with mineral-containing biomaterials.

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“…[34][35][36][37][38] As an additional approach, bioactive molecules can be anchored onto calcium-containing substrates through the use of negatively charged domains that bind to positively charged calcium ions. Examples of such domains include bisphosphonates [39][40][41][42] as well as sequences comprised of negatively charged amino acids, including glutamate, aspartate, or the noncanonical amino acids, gcarboxyglutamate and phosphoserine. [15][16][17]19,23,25,[43][44][45] For delivery of bioactive peptides, polyglutamate or polyaspartate domains offer some advantages over other types of calciumbinding modules.…”

Section: Discussionmentioning

confidence: 99%

Enhancement of the Regenerative Potential of Anorganic Bovine Bone Graft Utilizing a Polyglutamate-Modified BMP2 Peptide with Improved Binding to Calcium-Containing Materials

Bain

Bonvallet

Abou‐Arraj

et al. 2015

Tissue Engineering Part A

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Autogenous bone is the gold standard material for bone grafting in craniofacial and orthopedic regenerative medicine. However, due to complications associated with harvesting donor bone, clinicians often use commercial graft materials that may lose their osteoinductivity due to processing. This study was aimed to functionalize one of these materials, anorganic bovine bone (ABB), with osteoinductive peptides to enhance regenerative capacity. Two peptides known to induce osteoblastic differentiation of mesenchymal stem cells were evaluated: (1) DGEA, an amino acid motif within collagen I and (2) a biomimetic peptide derived from bone morphogenic protein 2 (BMP2pep). To achieve directed coupling of the peptides to the graft surface, the peptides were engineered with a heptaglutamate domain (E7), which confers specific binding to calcium moieties within bone mineral. Peptides with the E7 domain exhibited greater anchoring to ABB than unmodified peptides, and E7 peptides were retained on ABB for at least 8 weeks in vivo. To assess the osteoinductive potential of the peptide-conjugated ABB, ectopic bone formation was evaluated utilizing a rat subcutaneous pouch model. ABB conjugated with full-length recombinant BMP2 (rBMP2) was also implanted as a model for current clinical treatments utilizing rBMP2 passively adsorbed to carriers. These studies showed that E7BMP2pep/ABB samples induced more new bone formation than all other peptides, and an equivalent amount of new bone as compared with rBMP2/ABB. A mandibular defect model was also used to examine intrabony healing of peptide-conjugated ABB. Bone healing was monitored at varying time points by positron emission tomography imaging with 18 F-NaF, and it was found that the E7BMP2pep/ABB group had greater bone metabolic activity than all other groups, including rBMP2/ABB. Importantly, animals implanted with rBMP2/ABB exhibited complications, including inflammation and formation of cataract-like lesions in the eye, whereas no side effects were observed with E7BMP2pep/ABB. Furthermore, histological analysis of the tissues revealed that grafts with rBMP2, but not E7BMP2pep, induced formation of adipose tissue in the defect area. Collectively, these results suggest that E7-modified BMP2-mimetic peptides may enhance the regenerative potential of commercial graft materials without the deleterious effects or high costs associated with rBMP2 treatments.

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Bone Affinity of a Bisphosphonate-Conjugated Protein in Vivo

Cited by 38 publications

References 8 publications

Targeting Systemically Administered Proteins to Bone by Bisphosphonate Conjugation

Targeting Systemically Administered Proteins to Bone by Bisphosphonate Conjugation

Imparting mineral affinity to proteins with thiol–labile disulfide linkages

Enhancement of the Regenerative Potential of Anorganic Bovine Bone Graft Utilizing a Polyglutamate-Modified BMP2 Peptide with Improved Binding to Calcium-Containing Materials

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