PMID- 10978848 OWN - NLM STAT- MEDLINE DCOM- 20001019 LR - 20200106 IS - 0736-5748 (Print) IS - 0736-5748 (Linking) VI - 18 IP - 7 DP - 2000 Nov TI - Prolactin concurrently activates src-PLD and JAK/Stat signaling pathways to induce proliferation while promoting differentiation in embryonic astrocytes. PG - 693-704 AB - In normal development, embryonic astrocytes progress through their cell lineage by acquiring differentiation, by apoptosis, and by proliferation. In this study, we show that embryonic astrocytes may maintain and make gains in differentiation as they simultaneously progress through one cell cycle when induced by prolactin (PRL). Prolactin induced the majority of astrocytes to incorporate bromodeoxyuridine (BrdU) with a four-fold increase over controls after 18 h of exposure. Investigating possible mitogenic signaling pathways we show for the first time that prolactin is coupled to a sustained phospholipase D (PLD) activation, with an efficacy similar to the phorbol ester and astrocytic mitogen 12-tetradecanoylphorbol-13-acetate (TPA). Both cyclosporine and suramin abolished this activation. Staurosporine and calphostin C also inhibited the PRL effect by 50%, consistent with involvement of protein kinase C-(PKC)-alpha, the major PKC isoform in astrocytes. Genistein and PP1 blocked the activation indicating additional regulation by cytosolic tyrosine kinases. This profile of PLD activation was suggestive of a PLD I isoform and a mitogenic response. Upon completion of the cell cycle, analysis of glia fibrillary acidic protein (GFAP) and vimentin abundance, and glutamine synthetase (GS) activity showed that astrocytes had gained in expression of differentiation markers. Moreover, the intensity of GFAP immunofluorescence was greater per cell, as was the length of the cell processes. In exploring the signaling for prolactin-induced differentiation we found that prolactin activated the tyrosine kinase Janus kinase (JAK) 2 and significantly stimulated tyrosine, phosphorylation of the prolactin receptor. Stat 1 and 3 were also activated presumably downstream to JAK2 activation. A rapid translocation of the cytosolic Stats over the nucleus was seen in nearly every astrocyte corresponding well with the gains in GFAP per cell. The Stats translocation did not depend on MEK-ERK inhibition by PD98059, inhibition of p38 by 1 microm SB203580, or Src kinase family inhibition by PP1. Our results demonstrate the ability of PRL to concurrently induce activation of PLD, a mitogenic signaling pathway in astrocytes, and prolonged stimulation of Stat1, compatible with the increased GFAP upregulation and cell differentiation. Considered together this data may provide an explanation on the fast gain in both numbers and differentiation in the astrocytic population during development (HD 09402, CRF). FAU - Mangoura, D AU - Mangoura D AD - Department of Pediatrics, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA. dm36@midway.uchicago.edu FAU - Pelletiere, C AU - Pelletiere C FAU - Leung, S AU - Leung S FAU - Sakellaridis, N AU - Sakellaridis N FAU - Wang, D X AU - Wang DX LA - eng GR - HD-09402/HD/NICHD NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - United States TA - Int J Dev Neurosci JT - International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience JID - 8401784 RN - 0 (Antimetabolites) RN - 0 (Nerve Tissue Proteins) RN - 9002-62-4 (Prolactin) RN - EC 2.7.10.1 (Protein-Tyrosine Kinases) RN - EC 2.7.10.2 (Jak3 protein, mouse) RN - EC 2.7.10.2 (Janus Kinase 3) RN - EC 2.7.10.2 (src-Family Kinases) RN - EC 2.7.11.13 (Protein Kinase C) RN - EC 3.1.4.4 (Phospholipase D) RN - EC 6.3.1.2 (Glutamate-Ammonia Ligase) RN - G34N38R2N1 (Bromodeoxyuridine) SB - IM MH - Animals MH - Antimetabolites MH - Astrocytes/*physiology MH - Blotting, Western MH - Bromodeoxyuridine MH - Cell Differentiation/physiology MH - Cell Division/physiology MH - Cells, Cultured MH - Glutamate-Ammonia Ligase/metabolism MH - Immunohistochemistry MH - Janus Kinase 3 MH - Mice MH - Nerve Tissue Proteins/biosynthesis MH - Phospholipase D/*physiology MH - Precipitin Tests MH - Prolactin/*physiology MH - Protein Kinase C/physiology MH - Protein-Tyrosine Kinases/*physiology MH - Signal Transduction/*physiology MH - src-Family Kinases/*physiology EDAT- 2000/09/09 11:00 MHDA- 2000/10/21 11:01 CRDT- 2000/09/09 11:00 PHST- 2000/09/09 11:00 [pubmed] PHST- 2000/10/21 11:01 [medline] PHST- 2000/09/09 11:00 [entrez] AID - S0736-5748(00)00031-9 [pii] AID - 10.1016/s0736-5748(00)00031-9 [doi] PST - ppublish SO - Int J Dev Neurosci. 2000 Nov;18(7):693-704. doi: 10.1016/s0736-5748(00)00031-9.