Abstract 4817

Introduction:

Parathyroid hormone (PTH) is a major regulator of calcium and phosphate metabolism and is secreted by the cells of the parathyroid gland. Recent research showed that PTH treatment may regulate the hematopoietic stem cell niche, leading to beneficial effects on the HSC pool, and increasing stem cell number and the number of stem cells mobilized into the bloodstream. Many studies demonstrated that the serum PTH was decreased but maintained at the lower level suggesting persisting PTH secretion after total parathyroidectomy without autotransplantation. Some research showed that the thymus is another source of PTH. Can the bone marrow cells express PTH mRNA and release PTH and be a third source of PTH production? The aim of this study was to explore whether PTH could be expressed in bone marrow stem cells(BMSCs).

Method:

BMSCs were separated from adult male SD rat bone marrow and were cultured in DMEM supplemented with 10% fetal bovine serum. The total RNA was extracted using Trizol one-step method. RT-PCR was performed to examine the expression of PTH and GAPDH in BMSCs. The optical densities (ODs) value of RT-PCR product was measured using the Gel Imageware System. The signal intensity of PTH bands was normalized by corresponding GAPDH bands. The ODs in each sample were expressed as a ratio PTH over GAPDH densitometric intensities. The resultant PCR product of PTH was sequenced in both directions. Immunocytochemistry staining was utilized to examine the expression of PTH in the BMSCs from adherent cell fraction of the 2nd passage.

Results:

The expressions of PTH mRNA in BMSCs were detected in all 11 rats by RT-PCR. The PCR product was 193bp for PTH (Fig 1). The ratio of PTH over GAPDH ODs value ranged from 0.4407 to 3.1506, and the average ODs value (m ± SD) was 1.2617 ± 0.8953. The sequence of the PTH PCR products matched 100% with the PTH sequence in Genebank (Gene ID: 24694 Pth; gb K01268.1 RATPTH3, Rat parathyroid hormone gene, exons II and III). Some of the BMSCs were PTH positive by immunocytochemistry. The PTH positive cells were middle in size and spindle. PTH staining was localized in the cytoplasma and cell membrane of BMSCs cultured (Fig 2).

Conclusion:

The PTH mRNA and protein were detected in BMSCs. The results suggest that the BMSCs may be a third cell source responsible for the synthesis and secretion of PTH. It would be interesting to know what type of cells in BMSCs is secreating the PTH and to explore the role of PTH in bone marrow stem cell niche.

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Disclosures:

No relevant conflicts of interest to declare.

Topics:
bone marrow, calcium, gel, parathyroid hormones, parathyroidectomy, complete, phosphates, polymerase chain reaction, rats, reverse transcriptase polymerase chain reaction, rna

The research was supported by National Basic Research Program of China Grant 2009CB522902 and National Natural Science Foundation of China Grant 30960409.

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2011 by The American Society of Hematology
2011
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