Merja Sulkala

Publications (3)2.8 Total impact

• Article: Matrix metalloproteinase-8 (MMP-8) is the major collagenase in human dentin.

  Merja Sulkala, Taina Tervahartiala, Timo Sorsa, Markku Larmas, Tuula Salo, Leo Tjäderhane
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  ABSTRACT: Previously an unidentified collagenolytic metalloprotease together with gelatinase (matrix metalloproteinase-2, MMP-2), and enamelysin (MMP-20) have been detected in human dentin. The aim of the study was to characterize dentinal collagenolytic enzymes. Furthermore, we hypothesized that the dentinal MMPs are protected by the mineral phase, and studied the stability of dentinal MMPs. To characterize dentinal collagenolytic enzymes, we used Western blotting with specific antibodies against MMP collagenases (MMP-1, -8, and -13) and cathepsin K. MMP-8 immunofluorometric assay (IFMA) was also used for MMP-8 detection, and functional collagenase activity was examined with type I collagen degradation assay. The stability of dentinal MMPs was examined by autoclaving dentin blocks before protein extraction and subsequent examination of protein levels and the activities of dentin collagenase and gelatinases. MMP-8 (collagenase-2) was detected in dentin both with Western blot and IFMA, and dentinal samples also cleaved the intact type I collagen into characteristic 3/4(alphaA)-cleavage products in vitro. No other collagenases or cathepsin K were detected. In autoclaved samples no MMP-8 was found, but gelatinase activity was observed in protein fractions of mineralized dentin. MMP-8 represents the major collagenase in human dentin. Unlike MMP-8, dentinal gelatinases can be detected after autoclave treatment of dentin, indicating their high resistance to external sample treatment procedures.
  Archives of Oral Biology 03/2007; 52(2):121-7. · 1.60 Impact Factor
• Article: Matrix metalloproteinase-13 (MMP-13, collagenase-3) is highly expressed in human tooth pulp.

  Merja Sulkala, Virve Pääkkönen, Markku Larmas, Tuula Salo, Leo Tjäderhane
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  ABSTRACT: Matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) participate into extracellular matrix degradation in physiological and pathological conditions. We hypothesized that MMP expression in pulp tissue changes in response to caries attack and investigated the gene expression profiles of MMPs and TIMPs in pulp tissue of sound and carious teeth with cDNA microarray. cDNA microarray demonstrated an extremely high MMP-13 (collagenase-3) mRNA expression in pooled pulp samples of sound and carious teeth, with less pronounced expression of MMP-16 (MT3-MMP) and TIMP-1. Real-time quantitative polymerase chain reaction of individual pulp samples revealed a wide range of the MMP-13 expression level between pulp samples with possible downregulation of MMP-13 expression during caries progression. Western blot and immunohistochemical staining confirmed the presence of MMP-13 with no observable differences between sound and carious teeth pulp tissues. The results reveal that MMP-13 is expressed and synthesized in pulp tissue, an interesting feature considering the very limited expression of MMP-13 in normal adult tissues. Further studies with a larger sample size are needed to clarify the changes in MMP-13 expression during caries progression.
  Connective Tissue Research 02/2004; 45(4-5):231-7. · 1.20 Impact Factor
• Article: Matrix metalloproteinases (MMPs) in the dentin-pulp complex of healthy and carious teeth /

  Merja. Sulkala
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  ABSTRACT: Diss. -- Oulun yliopiso.