Matrix metalloproteinase 9 regulates cell death following pilocarpine-induced seizures in the developing brain.
Matrix metalloproteinases (MMPs) are involved in tissue repair, cell death and morphogenesis. We investigated the role of the gelatinases MMP-2 and MMP-9 in the pathogenesis of neuronal death induced by prolonged seizures in the developing brain. Seven-day-old rats, MMP-9 knockout mice and transgenic rats overexpressing MMP-9 received intraperitoneal injections of pilocarpine, 250 mg/kg, to induce seizures. After 6-72 h pups were sacrificed, tissue from different brain regions was isolated and expression of MMP-9 mRNA and protein was analyzed by real-time PCR or Western blot. Additionally, brains were fixed and processed for TUNEL-staining, immunohistochemistry and in situ zymography. We found increased numbers of TUNEL-positive cells 24 h after pilocarpine-induced seizures, most pronounced in cortical areas and the dentate gyrus, and less pronounced in thalamus. At 6-24 h, MMP-9 mRNA levels showed significant elevation compared to sham-treated controls; this effect resolved by 48 h, whereas MMP-2 mRNA levels remained stable. Cortical gelatinolytic activity, monitored by in situ zymography, was enhanced following pilocarpine-induced seizures. The MMP inhibitor GM 6001 ameliorated cell death following pilocarpine-induced seizures in infant rats. MMP-9 knockout mice were less susceptible to seizure-induced brain injury. Transgenic rats overexpressing MMP-9 were equally susceptible to seizure-induced brain injury as wild type rats. Our results suggest a significant contribution of MMP-9 to cell death after pilocarpine-induced seizures in the developing brain. As indicated by Western blot analysis, MMP-9 activation may be linked to activation of the Erk/CREB-pathway. The findings implicate involvement of MMP-9 in the pathophysiology of brain injury following seizures in the developing brain.
Department of Pediatric Neurology, Children's Hospital, Medical Faculty Carl Gustav Carus, Technical University Dresden, Fetscherstrasse 74, 01307 Dresden, Germany.
Yvonne
Y
Hoehna
Ortrud
O
Uckermann
Hella
H
Luksch
Vanya
V
Stefovska
Jenny
J
Marzahn
Marlen
M
Theil
Tomasz
T
Gorkiewicz
Maciej
M
Gawlak
Grzegorz M
GM
Wilczynski
Leszek
L
Kaczmarek
Chrysanthy
C
Ikonomidou
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D001921:Brain / Q000201:enzymology* / Q000473:pathology; D003292:Convulsants / Q000633:toxicity; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D020780:Matrix Metalloproteinase 9 / Q000172:deficiency / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009410:Nerve Degeneration; D010862:Pilocarpine / Q000633:toxicity; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D055647:Rats, Transgenic; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012640:Seizures / Q000139:chemically induced / Q000201:enzymology* / Q000473:pathology
D003292:Convulsants; D012333:RNA, Messenger; D010862:Pilocarpine; D020780:Matrix Metalloproteinase 9