Title: 3025 - Fluoride Affects Calcium Uptake in the MC3T3 Pre-osteoblast Cell Line
Ronna Abaeyv (Presenter)
New York University
Johnny Groeling, New York University
Veronica Costiniti, New York University
Miriam Eckstein, New York University
Rodrigo Lacruz, New York University
Objectives: Skeletal fluorosis (SF) is associated with high levels of fluoride ingestion from various sources including ground water or toothpaste, or as an air pollutant. This leads to an excessive accumulation of fluoride in bones increasing bone mass, also causing calcification of the joints and pain. Bones become less elastic increasing the risk of fractures. However, how fluoride can stimulate bone formation remains unclear. Here we use an in vitro approach to determine whether fluoride affects intracellular calcium concentration and SOCE in MC3T3 cells, as well as its effects on bone growth markers.
Methods: Undifferentiated MC3T3 cells were treated with varying concentrations of sodium fluoride (NaF) (0.5 mM and 1.0 mM) for 24 hr before analyzing changes in intracellular calcium and SOCE. We also analyzed the expression of key genes associated with bone growth and mineralization by real time PCR. After NaF treatment, cells were loaded with the cytosolic calcium dye Fura2-AM and stimulated with thapsigargin to passively deplete the endoplasmic reticulum (ER) calcium stores, before re-addition of 2 mM Ca2+ to stimulate SOCE. Cells were imaged in the Flexstation III plate reader. A different subset of cells was used to isolate RNA for gene expression analyses.
Results: We found that NaF treated MC3T3 cells showed decreased ER Ca2+ and SOCE in a dose dependent manner. We also identified changes in gene expression in alkaline phosphatase (ALP) and RUNX2.
Conclusions: Our results indicate that NaF treated cells, at both concentrations, have an impact on calcium homeostasis in pre-osteoblastic MC3T3 cells. These preliminary data are important step to better understand the effects of fluoride in various stages of bone cell development. Future studies will compare these data with that of differentiated (osteoblast-like) MC3T3 cells to determine the effects of fluoride in bone formation and SF.
This abstract is based on research that was funded entirely or partially by an outside source:
NIDCR: DE027679 and DE025639
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE