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Thymosin β 4 and Its N‐Terminal Tetrapeptide, AcSDKP, Inhibit Proliferation, and Induce Dysplastic, Non‐Apoptotic Nuclei and Degranulation of Mast Cells
Author(s) -
Leeanansaksiri Wilairat,
DeSimone Shirley K.,
Huff Thomas,
Hannappel Ewald,
Huff Thomas F.
Publication year - 2004
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.200490081
Subject(s) - degranulation , tetrapeptide , chemistry , apoptosis , microbiology and biotechnology , mast cell , biophysics , biochemistry , immunology , peptide , receptor , biology
Thymosin β 4 (T β 4 ), a 5 kDa polypeptide, is a member of the β ‐thymosin family. It acts as the principal intracellular G‐actin sequestering peptide and exhibits extracellular functions in angiogenesis and wound healing. The N‐terminus of T β 4 contains a bioactive tetrapeptide, acSDKP, a negative regulator of hematopoietic stem‐cell proliferation. Here, we show that both peptides inhibit mast‐cell proliferation over the concentration range of 10 −6 to 10 −17 M with the maximum effect of both at 10 −14 M . Both T β 4 and acSDKP caused dysplastic mast‐cell nuclei that were confirmed by DAPI fluorescent staining. Flow‐cytometric analysis of ploidy revealed that the dysplastic nuclei were not multinucleated, but fragmented nuclei in G2 growth arrest. We could further demonstrate that 10 −8 or 10 −14 M T β 4 or acSDKP induce mast‐cell degranulation. A concentration of 10 −8 M T β 4 or acSDKP caused 57 or 89% degranulation, respectively. A number of tryptic fragments of T β 4 were assayed beside intact T β 4 and the tetrapeptide, and found to be inactive.