Immunoreactive Akt, PI3-K and ERK protein kinase expression in ischemic rat brain

Kitagawa, Hisashi; Warita, Hitoshi; Sasaki, Chihoko; Zhang, Wen Ri; Sakai, Kenichi; Shiro, Yoshihiko; Mitsumoto, Yasuhide; Mori, Toyoki; Abe, Kōji

doi:10.1016/s0304-3940(99)00676-x

Cited by 87 publications

(49 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, the concomitant decline in total β-catenin levels seen after pMCAO is in accordance with this notion, since activated GSK3 has been previously suggested to induce apoptosis through phosphorylation of β-catenin, thus marking it for degradation 41 ; β-catenin is a transcription factor that plays key roles in cell survival 42 . Our results are consistent with those observed by others: downregulation of the PI3-K/Akt signal pathway has been described up to 24 hrs after pMCAO [51][52][53][54] . Conversely, in the presence of E2 and P4, we detected an increase in Akt phosphorylation levels at Ser473 and Thr308, and in GSK3α/β at Ser21/9 in the ipsi-Ctx, correlating with both enhanced Akt activity and reduced GSK3α/β activity.…”

Section: Discussionsupporting

confidence: 94%

Combined estradiol and progesterone: a potentially valuable therapeutic treatment for human ischemic stroke

Alonso

2013

Sanid. Mil.

View full text Add to dashboard Cite

SUMMARY Introduction:Ischemic stroke leads adult's mortality and long-term disability. Thus, new therapeutic approaches are needed. Estradiol (E2) and progesterone (P4) protect a variety of neuronal cells under stroke-like conditions in vitro; and the rodent brain against injury in vivo when administered prior to the ischemic insult, namely middle cerebral artery occlusion (MCAO). But, their therapeutic value after MCAO has been hardly studied. Less is known when coadministered under this paradigm. E2 and P4 also protect the neuronal cell death in vitro from ischemic-like injury, by reducing apoptotic cell death and enhancing cell survival signals. Here, we assessed the effect of combined E2 and P4 treatment in rats after permanent MCAO (pMCAO), which best mimics human ischemic stroke, analyzing the phosphatidylinositol 3-kinase (PI3-K)/Akt/glycogen synthase kinase 3 (GSK3)/ß-catenin signal pathway and the activation status of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in the infarct core (i.e., the ipsilateral frontoparietal cortex, ipsi-Ctx). Materials and Methods: Age-matched male Wistar rats (n=48) underwent pMCAO or sham operation and received either vehicle (ethanol 1% in saline) or combined E2 and P4 (0.04 mg/kg and 4 mg/kg, respectively) treatment at 6, 24, and 48 hrs after surgery. All animals were sacrificed 6 hrs after the last treatment dose and ipsi-Ctx homogenates were analyzed by immunoblotting. Results: pMCAO downregulated the PI3-K/Akt/GSK3/ß-catenin survival pathway and activated the proapoptotic protein SAPK/JNK in the ipsi-Ctx, effects which were reversed by E2 and P4 coadministration. Conclusions: Our data show that combined E2 and P4 treatment exerts a neuroprotective effect against brain injury when administered after the ischemic insult, which is mediated by modification of the activity of PI3-K/Akt/GSK3/ß-catenin signal pathway and that of SAPK/JNK. Hence, we provide experimental evidence that combined E2 and P4 comprise a potentially valuable therapeutic treatment for human ischemic stroke.KEY WORDS: Estradiol, Progesterone, pMCAO, Ischemic stroke, Brain, Neuroprotection, Frontoparietal cortex, Immunoblotting, Akt, SAPK/JNK.Combinación de estradiol y progesterona: un tratamiento potencialmente valioso para el ictus isquémico en humanos RESUMEN Introducción: El ictus isquémico es una principal causa de muerte y discapacidad a largo plazo en adultos. Por tanto, es necesario desarrollar nuevas terapias. El estradiol (E2) y la progesterona (P4) protegen a distintas neuronas bajo condiciones que simulan el ictus isquémico in vitro; así como el cerebro de roedores cuando se administran antes del daño isquémico in vivo, en concreto antes de la oclusión de la arteria cerebral media (MCAO). Sin embargo, su valor terapéutico tras la MCAO ha sido poco estudiado. Menos se sabe aún acerca de su efecto cuando se coadministran en esta circunstancia. Además, el E2 y la P4 previenen la muerte neuronal por daño isquémico in vitro, disminuyendo la apoptosis y aumentando las señales...

show abstract

Section: Discussionsupporting

confidence: 94%

Combined estradiol and progesterone: a potentially valuable therapeutic treatment for human ischemic stroke

Alonso

2013

Sanid. Mil.

View full text Add to dashboard Cite

show abstract

“…PI3-K is thought to regulate cell death by activating the serinethreonine protein kinase Akt (3), which enhances the activity of antiapoptotic proteins through the transcription factor NF-B and inhibits proapoptotic signaling by Bad, caspase-9, and other effectors (43). The fact that several of these proteins are induced or activated in ischemic brain (44)(45)(46)(47)(48) is consistent with a role for VEGFR-2͞PI3-K signaling in the regulation of hypoxic or ischemic neuronal cell death.…”

Section: Discussionmentioning

confidence: 87%

Vascular endothelial growth factor: Direct neuroprotective effect in in vitro ischemia

Jin

Mao

Greenberg

2000

Proc. Natl. Acad. Sci. U.S.A.

633

429

View full text Add to dashboard Cite

Vascular endothelial growth factor (VEGF) is a hypoxia-inducible angiogenic peptide with recently identified neurotrophic effects. Because some neurotrophic factors can protect neurons from hypoxic or ischemic injury, we investigated the possibility that VEGF has similar neuroprotective properties. In HN33, an immortalized hippocampal neuronal cell line, VEGF reduced cell death associated with an in vitro model of cerebral ischemia: at a maximally effective concentration of 50 ng͞ml, VEGF approximately doubled the number of cells surviving after 24 h of hypoxia and glucose deprivation. To investigate the mechanism of neuroprotection by VEGF, the expression of known target receptors for VEGF was measured by Western blotting, which showed that HN33 cells expressed VEGFR-2 receptors and neuropilin-1, but not VEGFR-1 receptors. The neuropilin-1 ligand placenta growth factor-2 failed to reproduce the protective effect of VEGF, pointing to VEGFR-2 as the site of VEGF's neuroprotective action. Two phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, reversed the neuroprotective effect of VEGF, implicating the phosphatidylinositol 3-kinase͞Akt signal transduction system in VEGF-mediated neuroprotection. VEGF also protected primary cultures of rat cerebral cortical neurons from hypoxia and glucose deprivation. We conclude that in addition to its known role as an angiogenic factor, VEGF may exert a direct neuroprotective effect in hypoxic-ischemic injury.

show abstract

“…Ischaemia activates phosphorylation of ERKs, p38, JNK and PI3K in the brain [18,25,27] and of PI3K and MAPK in the retina [9], but, in most cases, phosphorylation occurs rather in connection with reperfusion, and in any case a link with amino acid fluxes has been established. An important point often raised is the extent to which amino acid efflux in ischaemia is a primary response to swelling concurrent with the ischaemic episode.…”

Section: Discussionmentioning

confidence: 99%

Tyrosine kinases and amino acid efflux under hyposmotic and ischaemic conditions in the chicken retina

Paz¹,

Lezama²,

Torres-Márquez³

et al. 2002

Pfl�gers Archiv European Journal of Physiology

View full text Add to dashboard Cite

The chicken retina was exposed to 20% hyposmotic or ischaemia-like (54 mM KCl and 1 mM ouabain) conditions and changes in cell volume, amino acid release and activation of protein tyrosine kinases measured. To investigate possible connection between these cellular events, the effect of tyrosine kinase blockers on (3)H-taurine, (3)H-GABA and (3)H- D-aspartate (as a tracer for glutamate) efflux was examined. Both hyposmotic and ischaemic conditions increased phosphorylation of the tyrosine kinase p125 focal adhesion kinase (p125(FAK)) and the mitogen-activated protein kinase-p38 (MAPK-p38), but not of the extracellular-signal-related kinases-1/2 (ERK1/ERK2), and markedly activated the tyrosine kinase target enzyme phosphatidylinositide 3-kinase (PI3K). Hyposmolarity and ischaemia both led to rapid retinal swelling followed by active volume recovery of 84% (hyposmolarity) and 40% (ischaemia), together with rapid release of taurine, GABA and D-aspartate. Taurine and GABA efflux under both conditions was reduced markedly by tyrosine kinase and PI3K blockers (50 microM tyrphostin A23, 50 microM genistein, 100 nM wortmannin, 25 microM LY294002) and was decreased by 85% when ischaemia-induced swelling was prevented. About 65% of D-aspartate efflux occurred irrespective of swelling in ischaemia and was either less sensitive (hyposmotic) or largely resistant (ischaemia) to the blockers. These results suggest that in ischaemia, GABA and taurine react primarily to swelling with a typical osmolyte response, while glutamate differs in its release mechanisms under both hyposmotic and ischaemic conditions. These findings suggest new strategies for evaluating the contribution of swelling to excitotoxicity in ischaemia.

show abstract

Immunoreactive Akt, PI3-K and ERK protein kinase expression in ischemic rat brain

Cited by 87 publications

References 21 publications

Combined estradiol and progesterone: a potentially valuable therapeutic treatment for human ischemic stroke

Combined estradiol and progesterone: a potentially valuable therapeutic treatment for human ischemic stroke

Vascular endothelial growth factor: Direct neuroprotective effect in in vitro ischemia

Tyrosine kinases and amino acid efflux under hyposmotic and ischaemic conditions in the chicken retina

Contact Info

Product

Resources

About