Synthesis of transforming growth factor-beta 1 by megakaryocytes and its localization to megakaryocyte and platelet alpha-granules

Autor: R A, Fava, T T, Casey, J, Wilcox, R W, Pelton, H L, Moses, L B, Nanney
Rok vydání: 1990
Předmět:
Zdroj: Blood. 76:1946-1955
ISSN: 1528-0020
0006-4971
DOI: 10.1182/blood.v76.10.1946.bloodjournal76101946
Popis: We have directly demonstrated that megakaryocytes are a major site of synthesis and storage of transforming growth factor-beta 1 (TGF/beta 1) by combined immunohistochemical, immunocytochemical, and in situ hybridization methods. The presence of TGF/beta 1 messenger RNA (mRNA) in mature megakaryocytes in adult rat spleen and bone marrow (BM) was established by in situ hybridization. Localization of TGF/beta 1 protein to intact alpha-granules of megakaryocytes, its putative storage site, was accomplished in glycol-methacrylate embedded porcine BM with an immunoperoxidase technique and light microscopy. The TGF/beta 1 was sequestered in intracytoplasmic granules in a pattern virtually identical to that of another alpha-granule marker protein, fibrinogen. This observation strongly suggests packaging of TGF/beta 1 into this organelle within megakaryocytes. That TGF/beta 1 mRNA was localized to megakaryocytes suggests that the TGF/beta 1 found in the alpha-granules in platelets originates with megakaryocyte synthesis. The alpha-granule localization of TGF/beta 1, as well as fibrinogen, was also demonstrated in isolated platelets at the ultrastructural level by electronmicroscopy (EM) and postembedding colloidal-gold immunocytochemistry, thus directly demonstrating that alpha-granules are the final storage site for TGF/beta 1 in mature platelets.
Databáze: OpenAIRE
Externí odkaz: