In vivo expression of the interleukin 4 receptor alpha by astrocytes in epilepsy cerebral cortex.
We reported previously that non-neoplastic astrocytes (derived from brain tissues of patients with epilepsy) expressed interleukin 4 receptor alpha (IL-4Ralpha) and responded to interleukin 4 (IL-4) in culture. To determine whether reactivity of cultured astrocytes was relevant to primary tissue, we investigated IL-4Ralpha expression in specimens of non-neoplastic cerebral cortex removed for surgical treatment of intractable epilepsy compared to specimens of glial tumours, which have been reported to contain IL-4Ralpha. Freshly frozen tissues from eight cases (four epilepsy, four malignant astrocytoma) were evaluated for IL-4Ralpha expression by reverse-transcriptase polymerase chain reaction (RT-PCR), Southern blotting, and double-labelled immunohistochemistry with antibodies to IL-4Ralpha and glial fibrillary acidic protein (GFAP). IL-4Ralpha mRNA was detectable in both non-neoplastic and neoplastic tissues, whereas interleukin 2 receptor gamma chain (IL-2Rgammac) mRNA was not found. By immunohistochemistry, IL-4Ralpha protein co-localized to cells displaying GFAP and astrocytic morphology in epilepsy tissues. As anticipated, IL-4Ralpha was detectable in astrocytoma, but, surprisingly, was also observed in GFAP-positive, non-neoplastic "reactive" astrocytes adjacent to tumour. Results are consistent with the concept that non-neoplastic epilepsy astrocytes express IL-4Ralpha in situ, thus confirming in vitro studies and implying IL-4 sensitivity in vivo.
Liu
H
H
Rammelkamp Center for Education and Research, MetroHealth Medical Center, Cleveland, OH 44109, USA.
Prayson
R A
RA
Estes
M L
ML
Drazba
J A
JA
Barnett
G H
GH
Bingaman
W
W
Liu
J
J
Jacobs
B S
BS
Barna
B P
BP
D000199:Actins / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism*; D015139:Blotting, Southern; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000378:metabolism*; D004827:Epilepsy / Q000378:metabolism*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D015847:Interleukin-4 / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D019948:Receptors, Interleukin-4 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D000199:Actins; D005904:Glial Fibrillary Acidic Protein; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; D019948:Receptors, Interleukin-4; D015847:Interleukin-4