Aim: To evaluate whether and how the transcription factor early growth response gene 1 (EGR1) affects the osteogenic differentiation of dental stem cells.

Methology: Dental stem cells from apical papilla (SCAPs) and from the dental follicle (DFCs) were transfected with EGR1 specific siRNA or EGR-1 expression plasmid. Gene regulation was verified at protein level by Western blotting. The expression of the transcription factors distal-less homeobox 3 (DLX3), alkaline phosphatase (ALP), and bone morphogenetic protein 2 (BMP2), which are all regulators and markers of the osteogenic differentiation in dental stem cells, was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). To investigate the mineralization, SCAP long term cultures were stained with alizarin red after EGR1 over-expression.

Results: EGR1 was induced in SCAPs during osteogenic differentiation. DLX3 and bone morphogenetic protein 2 (BMP2) were up-regulated after EGR1 over-expression and down-regulated after EGR1 depletion. The expression of ALP was also down-regulated after EGR1 depletion. The over-expression of EGR1 in SCAPs promoted mineralization after osteogenic differentiation.

Conclusions: EGR1 supported the osteogenic differentiation of dental stem cells by potentially regulating the expression of DLX3 and BMP2.

Fragestellung: Beeinflusst early growth response gene 1 (EGR1) die osteogene Differenzierung in dentalen Stammzellen und wenn ja, was sind die möglichen Mechanismen dahinter?

Methodik: Dentale Stammzellen der apikalen Papille (SCAP) und dentale Follikelzellen (DFC) wurden mit einer EGR1-spezifischen siRNA oder einem EGR1-Expressionsplasmid transfiziert. Die Expression osteogener Markergene wurde auf RNA-Ebene mittels quantitative reverse transcription-polymerase chain reaction (qRT-PCR) und auf Proteinebene mittels Western Blot analysiert. Das osteogene Differenzierungsverhalten wurde durch Quantifizierung der Biomineralisierung untersucht.

Ergebnisse: EGR1 war während der osteogenen Differenzierung in SCAPs induziert. Die osteogenen Markergene distal-less homeobox 3 (DLX3) und bone morphogenetic protein 2 (BMP2) waren nach EGR1-Überexpression hochreguliert und nach EGR1-Herunterregulierung inhibiert. EGR1-Überexprimierung führte zu einer verstärkten Mineralisierung in SCAPs.