Molecular differences between stromal cell populations from deciduous and permanent human teeth.
BACKGROUND
Deciduous and permanent human teeth represent an excellent model system to study aging of stromal populations. Aging is tightly connected to self-renewal and proliferation and thus, mapping potential molecular differences in these characteristics between populations constitutes an important task.


METHODS
Using specifically designed microarray panels, Real-Time Quantitative Polymerase Chain Reaction (RT q-PCR), Western blot, immunohistochemistry and siRNA-mediated knock down experiments, we have detected a number of molecules that were differentially expressed in dental pulp from deciduous and permanent teeth extracted from young children and adults, respectively.


RESULTS
Among the differentially regulated genes, high-mobility group AT-hook 2 (HMGA2), a stem cell-associated marker, stood out as a remarkable example with a robust expression in deciduous pulp cells. siRNA-mediated knock down of HMGA2 expression in cultured deciduous pulp cells caused a down-regulated expression of the pluripotency marker NANOG. This finding indicates that HMGA2 is a pulpal stem cell regulatory factor. In addition to this, we discovered that several proliferation-related genes, including CDC2A and CDK4, were up-regulated in deciduous pulp cells, while matrix genes COL1A1, fibronectin and several signaling molecules, such as VEGF, FGFr-1 and IGFr-1 were up-regulated in the pulp cells from permanent teeth.


CONCLUSIONS
Taken together, our data suggest that deciduous pulp cells are more robust in self- renewal and proliferation, whereas adult dental pulp cells are more capable of signaling and matrix synthesis.
Center for Craniofacial Regeneration (CCR), Columbia University Medical Center, 630 W. 168 St. - PH7E, New York, NY, 10032, USA. nina.kaukua@ki.se.|Department of Neuroscience, Karolinska Institutet, Stockholm, SE-171 77, Sweden. nina.kaukua@ki.se.
Nina
N
Kaukua
Center for Craniofacial Regeneration (CCR), Columbia University Medical Center, 630 W. 168 St. - PH7E, New York, NY, 10032, USA. mc3013@cumc.columbia.edu.
Mo
M
Chen
Department of Systems Biology, Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY, 10032, USA. pg2296@c2b2.columbia.edu.
Paolo
P
Guarnieri
Department of Dental Medicine, Karolinska Institutet, Huddinge, SE 14104, Sweden. carlaxelmarkus@gmail.com.
Markus
M
Dahl
Advanced Center for Translational Regenerative Medicine (ACTREM), Department for Clinical Science, Intervention and Technology (CLINTEC), Division of Ear, Nose and Throat, Karolinska Institutet, Huddinge, SE 141 86, Sweden. mei.lim@ki.se.
Mei Ling
ML
Lim
Department of Dental Medicine, Karolinska Institutet, Huddinge, SE 14104, Sweden. tulay.lindberg@ki.se.
Tülay
T
Yucel-Lindberg
Division of Neurodegeneration, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, SE-14157, Sweden. erik.sundstrom@ki.se.
Erik
E
Sundström
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, SE 171 77, Sweden. igor.adameyko@ki.se.
Igor
I
Adameyko
Center for Craniofacial Regeneration (CCR), Columbia University Medical Center, 630 W. 168 St. - PH7E, New York, NY, 10032, USA. jmao@columbia.edu.
Jeremy J
JJ
Mao
Department of Neuroscience, Karolinska Institutet, Stockholm, SE-171 77, Sweden. kaj.fried@ki.se.
Kaj
K
Fried
D000328:Adult; D000375:Aging / Q000502:physiology; D016203:CDC2 Protein Kinase; D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D051358:Cyclin-Dependent Kinase 4 / Q000096:biosynthesis; D018844:Cyclin-Dependent Kinases / Q000096:biosynthesis; D003782:Dental Pulp / Q000378:metabolism*; D015536:Down-Regulation; D025743:HMGA2 Protein / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D006801:Humans; D008875:Middle Aged; D000071317:Nanog Homeobox Protein; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D034741:RNA, Small Interfering; D017154:Stromal Cells / Q000378:metabolism; D014094:Tooth, Deciduous / Q000378:metabolism*; D055815:Young Adult
D025743:HMGA2 Protein; D018398:Homeodomain Proteins; C486780:NANOG protein, human; D000071317:Nanog Homeobox Protein; D034741:RNA, Small Interfering; D016203:CDC2 Protein Kinase; C528899:CDK1 protein, human; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases