Bone repair by transplantation of hTERT-immortalized human mesenchymal stem cells in mice.
BACKGROUND
Human mesenchymal stem cells (hMSCs) are multipotent stem cells found in the adult bone marrow that have the capacity to differentiate into various mesenchymal cell types. The hMSCs may provide a potential therapy to restore damaged tissues or organs of mesenchymal origin; however, a drawback is their limited life span in vitro.


METHODS
We immortalized normal hMSCs with retrovirally transmitted human telomerase reverse transcriptase cDNA. One of the immortalized clones (YKNK-12) was established, and the biological characteristics were investigated in vitro and in vivo.


RESULTS
YKNK-12 cells were capable of differentiating adipocytes, osetoblasts, and chondrocytes. Osteogenically differentiated YKNK-12 cells produced significant levels of growth factors BMP4, BMP6, FGF6, FGF7, transforming growth factor-beta1, and transforming growth factor-beta3.. Microcomputer tomography T and soft X-ray assays showed an excellent calvarial bone healing in mice after transplantation of osteogenically differentiated YKNK-12 cells. These cells expressed human-specific osteocalcin and increased the gene expression of runt-related transcription factor 2, alkaline phosphatase, osteocalcin, and osterix in the bone regenerating area. YKNK-12 cell transplant corrected the bone defect without inducing any adverse effects.


CONCLUSIONS
We conclude that hMSCs immortalized by transduction with human telomerase reverse transcriptase may provide an unlimited source of cells for therapeutic use in bone regeneration.
Nakahara
Hiroyuki
H
Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Misawa
Haruo
H
Hayashi
Takahiro
T
Kondo
Eisaku
E
Yuasa
Takeshi
T
Kubota
Yasuhiro
Y
Seita
Masayuki
M
Kawamoto
Hironobu
H
Hassan
Wael A R A
WA
Hassan
Reham A R A
RA
Javed
Shahid M
SM
Tanaka
Masato
M
Endo
Hirosuke
H
Noguchi
Hirofumi
H
Matsumoto
Shinichi
S
Takata
Katsuyoshi
K
Tashiro
Yuichi
Y
Nakaji
Shuhei
S
Ozaki
Toshifumi
T
Kobayashi
Naoya
N
D017667:Adipocytes / Q000201:enzymology; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001847:Bone Diseases / Q000000981:diagnostic imaging / Q000201:enzymology / Q000503:physiopathology / Q000601:surgery*; D001861:Bone Regeneration; D002454:Cell Differentiation; D002461:Cell Line, Transformed; D019070:Cell Lineage; D049109:Cell Proliferation; D002470:Cell Survival; D019902:Chondrocytes / Q000201:enzymology; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010006:Osteoblasts / Q000201:enzymology; D010012:Osteogenesis; D011859:Radiography; D012886:Skull / Q000000981:diagnostic imaging / Q000201:enzymology / Q000503:physiopathology / Q000601:surgery*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014161:Transduction, Genetic
D015415:Biomarkers; D036341:Intercellular Signaling Peptides and Proteins; C509186:TERT protein, human; D019098:Telomerase