title: The pentapeptide KTTKS promoting the expressions of type I collagen and transforming growth factor-beta of tendon cells.
abstract: Pentapeptide KTTKS, a subfragment of type I collagen propeptide, has been demonstrated to promote the extracellular release of collagen in fibroblasts. The present study was designed to investigate the effect and molecular mechanism of KTTKS on type I collagen expression of rat Achilles tendon cells. Genes related to the upregulation of collagen expression such as transforming growth factor-beta (TGF-beta), and mRNA-binding proteins (mRBP) E1 and K were also examined. MTT assay revealed cell viability was not affected by KTTKS treatment. Protein expression of type I collagen was determined by immunocytochemistry and Western blot analysis. Results showed that KTTKS induced type I collagen expression of tendon cells. The mRNA expressions of alpha1(I) procollagen, TGF-beta, mRBP K, as determined by reverse transcription-polymerase chain reaction (RT-PCR), were also enhanced after KTTKS treatment. The stability of preexisting alpha1(I) procollagen mRNA after the addition of alpha-amanitin was analyzed by RT-PCR at 24 and 48 h. Results showed that KTTKS slowed down the degradation of alpha1(I) procollagen mRNA (p = 0.021). Furthermore, the concentration of TGF-beta in conditioned medium, as determined by enzyme-linked immunosorbent assay, increased dose dependently in cells treated with KTTKS (p = 0.001). In conclusion, KTTKS promotes the expression of type I collagen and maintains its mRNA stability in a process associated with the upregulation of TGF-beta.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, 259 Wen-Hwa 1 Road, Kweishan 333, Taoyuan, Taiwan.
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Tsai
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Hsu
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Chung
authors.forename: Miao-Sui
authors.initials: MS
authors.lastname: Lin
authors.forename: Sung-Lung
authors.initials: SL
authors.lastname: Li
authors.forename: Jong-Hwei S
authors.initials: JH
authors.lastname: Pang
mesh_terms: D000125:Achilles Tendon / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D024042:Collagen Type I / Q000096:biosynthesis*; D015870:Gene Expression; D009842:Oligopeptides / Q000494:pharmacology*; D051381:Rats; D016212:Transforming Growth Factor beta / Q000378:metabolism*
chemical_list: D024042:Collagen Type I; D009842:Oligopeptides; D016212:Transforming Growth Factor beta; C525923:lysyl-threonyl-threonyl-lysyl-serine