title: Latent transforming growth factor-β binding proteins (LTBP-1 and LTBP-2) and gingiva keratinization.
abstract: OBJECTIVE
  Transforming growth factor-beta (TGF-β) proteins are involved in epithelial keratinization. The major function of latent TGF-β binding proteins (LTBPs) is modulating TGF-β activity. However, whether LTBP-1 and LTBP-2 play roles in gingiva keratinization remains unclear.
  
  
  METHODS
  Human keratinized gingiva and non-keratinized alveolar mucosa were processed for LTBP-1, LTBP-2, cytokeratin-1 (K1), cytokeratin-4 (K4), and TGF-β immunohistochemical (IHC) staining. Porcine heterotopically transplanted connective tissues and newly grown epithelia were harvested for IHC staining. The expression levels of LTBP-1 and LTBP-2 were compared between differentiated and undifferentiated human normal oral keratinocytes (hNOK). The expression of LTBP-1 and LTBP-2 was knocked down in a cell line (OEC-M1) to evaluate the effects on the expression of K1, K4, and involucrin (INV).
  
  
  RESULTS
  In human and porcine specimens, LTBP-2 expression patterns distinguished keratinized and non-keratinized oral epithelia. Western blotting results showed that K1, LTBP-1, and INV proteins were upregulated in differentiated hNOK. In OEC-M1 cells, LTBP-2 knockdown resulted in upregulated the expression of K1 and INV and downregulated the expression of K4. LTBP-1 knockdown resulted in opposite effects.
  
  
  CONCLUSIONS
  The expression patterns of LTBP-2 differ in keratinized gingiva and non-keratinized mucosa. LTBP-1 and LTBP-2 are involved in the keratinization of oral epithelium; however, the underlying mechanism remains to be elucidated.
authors: Department of Oral Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.|Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors: M-S
authors: MS
authors: Chiang
authors: Division of Physiology, Livestock Research Institute, Council of Agriculture, Executive Yuan, Tainan, Taiwan.
authors: J-R
authors: JR
authors: Yang
authors: Department of Oral Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
authors: S-C
authors: SC
authors: Liao
authors: Department of Oral Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.
authors: C-C
authors: CC
authors: Hsu
authors: Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.|Dental Department, Tainan Municipal Hospital, Tainan, Taiwan.
authors: C-W
authors: CW
authors: Hsu
authors: Department of Oral Medicine, National Cheng Kung University Hospital, Tainan, Taiwan.|Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors: K
authors: K
authors: Yuan
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D055785:Gene Knockdown Techniques; D005881:Gingiva / Q000737:chemistry*; D006801:Humans; D053556:Keratin-1 / Q000378:metabolism*; D053527:Keratin-4 / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism; D053779:Latent TGF-beta Binding Proteins / Q000032:analysis* / Q000235:genetics; D009061:Mouth Mucosa / Q000737:chemistry; D011498:Protein Precursors / Q000378:metabolism*; D013552:Swine
chemical_list: D053556:Keratin-1; D053527:Keratin-4; C509032:LTBP1 protein, human; C509035:LTBP2 protein, human; D053779:Latent TGF-beta Binding Proteins; D011498:Protein Precursors; C032253:involucrin
keywords: cytokeratin; gingiva; keratinization; latent transforming growth factor-beta binding protein; transforming growth factor-beta