Involvement of protein kinase C-epsilon in signal transduction of thrombopoietin in enhancement of interleukin-3-dependent proliferation of primitive hematopoietic progenitors.
We studied the effect of thrombopoietin (TPO) on interleukin-3 (IL-3)-dependent bone marrow cell colony formation of mice to clarify the role of protein kinase C (PKC) in the signal transduction of TPO for the proliferation of primitive hematopoietic progenitors. TPO alone hardly yielded colonies. However, TPO in combination with IL-3 increased colony numbers synergistically from 2- to 4-fold, compared with those supported by IL-3 alone. Serial observation of colony development showed that TPO may hasten the appearance of colonies by shortening the dormant period (G(0)) of primitive progenitors. Immunocytochemical studies on PKC isoforms in progenitor cells stimulated with TPO have revealed that the expression pattern of PKC-epsilon is changed, but not that of PKC-alpha, -beta, -gamma, -delta, or -zeta. Selective PKC inhibitors, such as calphostin C and GF 109203X, and PKC-epsilon-specific translocation inhibitor peptide abrogated the enhancing effect of TPO on IL-3-dependent colony formation and the changes in the intracellular expression pattern of PKC-epsilon. These data taken together suggest that TPO has a direct effect on primitive progenitors and enhances IL-3-dependent colony formation, at least partly through the activation of PKC-epsilon.
Shiroshita
N
N
Third Department of Internal Medicine, Hokkaido University School of Medicine, Japan.
Musashi
M
M
Sakurada
K
K
Kimura
K
K
Tsuda
Y
Y
Ota
S
S
Iwasaki
H
H
Miyazaki
T
T
Kato
T
T
Miyazaki
H
H
Shimosaka
A
A
Asaka
M
M
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005472:Fluorouracil / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007150:Immunohistochemistry; D007377:Interleukin-3 / Q000378:metabolism* / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D051379:Mice; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013926:Thrombopoietin / Q000378:metabolism* / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007377:Interleukin-3; D007527:Isoenzymes; D013926:Thrombopoietin; C497256:Prkce protein, mouse; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D005472:Fluorouracil