Gewinnung und Charakterisierung von osteoblastären Zellen aus dem humanen Alveolarknochen
Sourcing and characterisation of osteoblastic cells from the human alveolar bone
by Diana Dillschneider
Date of Examination:2018-05-14
Date of issue:2018-05-14
Advisor:Prof. Dr. Nicolai Miosge
Referee:Prof. Dr. Nicolai Miosge
Referee:Prof. Dr. Heide Siggelkow
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Abstract
English
Osteoblasts represent one of the most important cell groups for bone forming as well as bone structuring and involve essentialy, together with osteoclasts and osteocytes, in the bone metabolism. Their main task, the secretion of different bone proteins and unmineralized bone matrix plays a key role in forming a functional skeleton. The osteoblastic cell group has been investigated in a lot of previous researches to examine their characteristics and produced proteins. Those studies were conducted in different animal models but not yet with cells from the human alveolar bone. This fact motivated to make the sourcing and characterisation of osteoblasts from the alveolar bone the theme of this study and to use some of the already elsewhere researched marker proteins for characterisation. The proteins CP-23 and sclerostin were added to this list due to the current discussion in literature about the close relation between this cell group and cementoblasts as well as osteocytes, as they strictly count as cement and osteocyte-specific. Furthermore the transcription factor sox9 was added to the study because of his already proven codependency to runx2. Four different methods were used for detailed characterisation: the quantitative polymerase chain reaction (qPCR), the western blot, the immunocytochemistry and the flow cytometry. Some surprising evidence was found in the results of the study. Mostly the low expression of collagen I, runx2, and decorin was unexpected whereas the expression of sox9 and CP-23 was found to be higher than the expression of some of the well-known bone proteins. CP-23 seems to be studied insufficient in his function as a cement-specific marker since his expression was higher in osteoblasts than in cementoblasts, here used as the control group. The osteoblast-specific marker sclerostin in turn was not detected in osteoblasts which enhances his status. A different approach was the review of some proteins after osteogenic differentiation of the cells whereby only the expression of CP-23 and osteocalcin was still possible. The increased osteocalcin and decreased CP-23 expression after differentiation follows the assumption that osteocalcin is a late osteoblastic marker and CP-23 possibly only exists in early stages of the osteoblastic differentiation It is to be assumed that the conducted osteoblastic differentiation was successful. The present study shows that some well-known bone proteins can be found in the human alveolar bone as well as some bone-unspecific proteins.
Keywords: osteoblast; alveolar bone; bone matrix; marker proteins