Mechanisms of Cellular Internalization of Quantum Dot® Conjugated Bone Formation Mimetic Peptide CK2.3
Open Access
- 9 July 2018
- journal article
- research article
- Published by MDPI AG in Nanomaterials
- Vol. 8 (7), 513
- https://doi.org/10.3390/nano8070513
Abstract
Osteoporosis is a debilitating skeletal disorder that is characterized by loss of bone density over time. It affects one in two women and one in four men, age 50 and older. New treatments that specifically drive bone formation are desperately needed. We developed a peptide, CK2.3, that acts downstream of the bone morphogenetic protein receptor type Ia and it induces osteogenesis in-vitro and in-vivo. However, its mechanism of action, especially its mode of uptake by cells remains unknown. To demonstrate CK2.3 internalization within a cell, we conjugated CK2.3 to Quantum Dot®s (Qdot®s), semiconductor nanoparticles. We purified CK2.3-Qdot®s by size exclusion chromatography and verified the conjugation and stability using UV/VIS and Fourier transform infrared spectroscopy. Our results show that CK2.3 was conjugated to the Qdot®s and the conjugate was stable for at least 4 days at 37 °C. Moreover, CK2.3-Qdot®s exerted biological response similar to CK2.3. Addition of CK2.3-Qdot®s to cells followed by confocal imaging revealed that CK2.3-Qdot®s were internalized at 6 h post stimulation. Furthermore, using pharmacological inhibitors against endocytic pathways, we demonstrated that CK2.3-Qdot®s were internalized by caveolae. These results show for the first time that the novel peptide CK2.3 is taken up by the cell through caveolae mediated endocytosis.Funding Information
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (1R01AR064242-010A1)
- National Institute of General Medical Sciences (P20GM103446)
This publication has 71 references indexed in Scilit:
- Caveolae regulate smad signaling as verified by novel imaging and system biology approachesJournal of Cellular Physiology, 2013
- Altered plasma membrane dynamics of bone morphogenetic protein receptor type Ia in a low bone mass mouse modelBone, 2012
- Casein Kinase 2 β-Subunit Is a Regulator of Bone Morphogenetic Protein 2 SignalingBiophysical Journal, 2010
- The Use of Inhibitors to Study Endocytic Pathways of Gene Carriers: Optimization and PitfallsMolecular Therapy, 2010
- Bisphosphonates: Mechanism of Action and Role in Clinical PracticeMayo Clinic Proceedings, 2008
- Dependence of Amide Vibrations on Hydrogen BondingThe Journal of Physical Chemistry B, 2008
- Potential clinical applications of quantum dotsInternational Journal of Nanomedicine, 2008
- Examination of Mineralized Nodule Formation in Living Osteoblastic Cultures Using Fluorescent DyesBiotechnology Progress, 2006
- Different Routes of Bone Morphogenic Protein (BMP) Receptor Endocytosis Influence BMP SignalingMolecular and Cellular Biology, 2006
- Cell lines and primary cell cultures in the study of bone cell biologyMolecular and Cellular Endocrinology, 2004