Protein Synthesis in Postischemic Rat Brain: A Two-Dimensional Electrophoretic Analysis

Abstract

Summary: This study examined the pattern of protein synthesis in the neocortex, caudate-putamen, and the hippocampus following transient forebrain ischemia in rats, The animal model of temporary ischemia used in this study causes permanent damage to vulnerable neu rons with a time course of injury that varies fr om hours (caudate nucleus) to days (hippocampus), To examine the spectrum of proteins synthesized in these regions at 3 and 18 h after recirculation, cerebral proteins were pulse-la beled in vivo by an intravenous injection of [ 3 sSJmethio nine. Newly synthesized (3sS-labeled) and constitutive (unlabeled) proteins were analyzed by two-dimensional gel electrophoresis and fluorography, In all three brain regions, specific proteins underwent preferential syn thesis (Mr �27,000, �65,000, �70,000, � I 10,000), while others showed decreased synthesis (neuron-specific eno lase, 0.-and l3-tubulin). There was an early (3 h post isch emia) induction of the Mr � 70,000 mammalian "stress"Tr ansient cerebral ischemia is associated with prolonged severe inhibition of brain protein syn thesis. Gradual recovery occurs long after energy metabolites have been restored and other metabolic processes normalized (Kleihues et aI. , 1975; Cooper et aI., 1977; Dienel et aI., 1980; Nowak et aI., 1985). Although the prolonged impairment of amino acid incorporation does not seem to reduce the total amount of brain protein or the activities of enzymes with low turnover rates, postischemic re- Schlesinger et al. (1982)]. In the present study newly synthesized ( 3 sS-labeled) proteins including stress proteins and constitutive (unlabeled) brain proteins were analyzed by two-dimensional gel electrophoresis and fluorography following the in vivo administration of [ 3 SS]methionine in control and postischemic animals. During transient ischemia (30 min) produced by occlusion of the four major arteries supplying the brain, all forebrain regions are severely ischemic but subsequently differ in the extent and rate of progression of neuronal cell death (Pulsinelli et aI., POSTlSCHEMIC PROTEIN SYNTHESIS IN RAT BRAIN 6431982a,b). Following restoration of cerebral blood flow, ischemic cell death progresses for several hours (in the caudate-putamen) to days (in the hip pocampus and neocortex). The majority of CAl py ramidal neurons and striatal small-to medium-sized neurons die, whereas injury to CA 3 pyramidal or neocortical neurons is relatively mild or absent. This phenomenon of selective and "delayed neu ronal cell death" (Kirino, 1982; Pulsinelli et aI. , 1982a) suggests that neurons remain viable throughout the ischemic period or even hours thereafter, but that certain sUbpopulations subse quently succumb owing to ischemia-induced meta bolic derangements of as-yet unidentified nature. The objective of this investigation was to assess whether regional differences in the spectrum of proteins synthesized by postischemic brain tissue exist and possibly predict the success or failure to recover from a potentially lethal insult. METHODS Ani...

The Two Patterns of Reactive Astrocytosis in Postischemic Rat Brain

“…These studies suggest that GFAP content and mRNA levels may increase by 2 days since there was proliferation of protein-synthesizing organelles including polyribosomes and RER as well as prolif eration of IFs. Furthermore, Kiessling et al (1986) found increased glial fibrillary protein content in ce rebral cortex and striatum at 18 h after cerebral ischemia produced by the same four-vessel occlu sion model. Alternatively, it is possible that some of the initial increases in GFAP immunohistochemis try during the first 24 h may also be due to post ischemic modification of GF AP with exposure of additional antigenic sites to GF AP antisera.…”

Differential Cerebral Protein Synthesis and Heat Shock Protein 70 Expression in the Core and Penumbra of Rat Brain after Transient Focal Ischemia

“…Beaucamp et al (3) demonstrated that overexpression of HSP70 in primary hippocampal neurons stabilizes and maintains the function of intracellular proteins, which suggests that HSP70 plays an important role in recovery. In stress conditions such as ischemia, the majority of CPS is used for stress proteins (12,15). Therefore, the expression of HSP70 may be an indicator that CPS will recover.…”

Persistent redistribution of poly-adenylated mRNAs correlates with translation arrest and cell death following global brain ischemia and reperfusion

“…However, it well-established that HSP70 is translated under conditions where general protein synthesis is inhibited (Panniers, 1994). In fact, exclusive synthesis of HSPs in reperfused hippocampus has been reported (Kiessling et al, 1986). Additionally, induced stress proteins such as HSP70 are crucial to recovery of general translation (DiDomenico et al, 1982;Van Nieuwenhoven et al, 2001;Ron 2002;Gilks et al, 2004).…”