Effect of MEPE-ASARM peptides on type I collagen and tissue-nonspecific alkaline phosphatase expression. A:

<p>Quantitative real-time PCR (as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056749#s2" target="_blank">Materials and Methods</a>) for type I collagen and tissue-nonspecific alkaline phosphatase expression in 3D cultures of SHEDs maintained in nonmineralizing (NM) or mineralizing (M) conditions in the absence or presence of either 20 µM phosphorylated (p-ASARM) or nonphosphorylated (np-ASARM) ASARM peptide for 21 days. mRNA expression levels were upregulated from day 7 to day 14 in M, M+p-ASARM and M+np-ASARM conditions and, at day 21, returned to a level comparable to that of the NM condition, except for alkaline phosphatase which remained high in the M+p-ASARM condition. <i>n</i> = 3, error bars +/− SD, * indicates significant difference (p<0.05) relative to NM condition. <b>B:</b> Sirius Red staining of collagen in deciduous tooth sections from a 3-year-old male XLH patient (upper right panel), permanent tooth sections from a 15-year-old female XLH patient (bottom right panel) and control patient (upper left panel) revealing an intact collagen distribution only where dentin has mineralized in the form of characteristic calcospherites (arrows), and not in the interglobular spaces (asterisks) in the dentin where mineralization is typically impaired in XLH and where matrix degradation occurs. Sirius Red staining of normal dentin (right panel) is generally homogeneous across the tubular dentin. Similarly, von Kossa staining counterstained with toluidine blue in the same XLH permanent tooth sections (bottom left panel) show lack of fusion of calcospherites (arrows) with large non-mineralized interglobular spaces (asterisks) in the dentin. o: odontoblast. pd: predentin. d: dentin. p: pulp.