Glial Fibrillary Acidic Protein Messenger Research Articles

Long-Term Outcomes of Adolescent THC Exposure on Translational Cognitive Measures in Adulthood in an Animal Model and Computational Assessment of Human Data

Although perceived as relatively harmless and nonaddictive, adolescent cannabis use significantly increases the likelihood of developing cannabis use disorder in adulthood, especially for high-potency cannabis. Risky decision-making is associated with chronic cannabis use, but given confounds of human studies, it remains unclear whether adolescent cannabis exposure and Δ9-tetrahydrocannabinol (THC) potency specifically predicts risky decision-making or influences cognitive response to the drug later in life. To leverage a human data set of cannabis users and a rat model to evaluate the long-term outcomes of adolescent THC exposure on adult decision-making and impulse control. This translational rat study tested the link between adolescent THC exposure and adulthood decision-making. A reanalysis of a previously published dataset of human chronic cannabis users was conducted to evaluate decision-making phenotypes. Computational modeling assessed the human and animal results in a single framework. Data were collected from 2017 to 2020 and analyzed from 2020 to 2022. Decision-making was measured by the Iowa Gambling Task (IGT) and Rat Gambling Task (rGT). Impulse control was assessed in the rat model. Computational modeling was used to determine reward and punishment learning rates and learning strategy used by cannabis users and THC-exposed rats. Cell-specific molecular measures were conducted in the prefrontal cortex and amygdala. Of 37 participants, 24 (65%) were male, and the mean (SD) age was 33.0 (8.3) years. Chronic cannabis users (n = 22; mean [SE] IGT score, -5.182 [1.262]) showed disadvantageous decision-making compared with controls (n = 15; mean [SE] IGT score, 7.133 [2.687]; Cohen d = 1.436). Risky choice was associated with increased reward learning (mean [SE] IGT score: cannabis user, 0.170 [0.018]; control, 0.046 [0.008]; Cohen d = 1.895) and a strategy favoring exploration vs long-term gains (mean [SE] IGT score: cannabis user, 0.088 [0.012]; control, 0.020 [0.002]; Cohen d = 2.218). Rats exposed to high-dose THC but not low-dose THC during adolescence also showed increased risky decision-making (mean [SE] rGT score: vehicle, 46.17 [7.02]; low-dose THC, 69.45 [6.01]; high-dose THC, 21.97 [11.98]; Cohen d = 0.433) and elevated reward learning rates (mean [SE] rGT score: vehicle, 0.17 [0.01]; low-dose THC, 0.10 [0.01]; high-dose THC, 0.24 [0.06]; Cohen d = 1.541) during task acquisition. These animals were also uniquely susceptible to increased cognitive impairments after reexposure to THC in adulthood, which was correlated with even greater reward learning (r = -0.525; P < .001) and a shift in strategy (r = 0.502; P < .001), similar to results seen in human cannabis users. Molecular studies revealed that adolescent THC dose differentially affected cannabinoid-1 receptor messenger RNA expression in the prelimbic cortex and basolateral amygdala in a layer- and cell-specific manner. Further, astrocyte glial fibrillary acidic protein messenger RNA expression associated with cognitive deficits apparent with adult THC reexposure. In this translational study, high-dose adolescent THC exposure was associated with cognitive vulnerability in adulthood, especially with THC re-exposure. These data also suggest a link between astrocytes and cognition that altogether provides important insights regarding the neurobiological genesis of risky cannabis use that may help promote prevention and treatment efforts.

Orphan designation: 2'-O-(2-methoxyethyl)-D-ribose antisense oligonucleotide targeting glial fibrillary acidic protein messenger ribonucleic acid, Treatment of Alexander disease

Orphan designation: 2'-O-(2-methoxyethyl)-D-ribose antisense oligonucleotide targeting glial fibrillary acidic protein messenger ribonucleic acid, Treatment of Alexander disease

Glial fibrillary acidic protein mRNA levels in the cingulate cortex of individuals with depression, bipolar disorder and schizophrenia

Recent studies have shown a decrease in glial number and glial fibrillary acidic protein (GFAP) levels in the frontal and cingulate cortices of individuals with mood disorders and schizophrenia. In an attempt to verify and expand these findings we examined GFAP messenger ribonucleic acid (mRNA) levels in postmortem sections of the anterior cingulate cortex (ACC) from the Stanley Neuropathology Consortium (SNC). The consortium consists of 15 cases in each of four groups (schizophrenia, bipolar disorder, non-psychotic depression and unaffected controls). By in situ hybridization, we found higher levels of GFAP mRNA in white matter and at the pial surface as compared with gray matter levels in all cases. In the white matter of ACC we detected a significant effect of diagnosis ( P<0.04) with GFAP mRNA levels decreased in individuals with schizophrenia and bipolar disorder as compared with normal controls. In the gray matter there was a significant effect of layer ( P<0.01) with the highest levels of GFAP mRNA in layer VI in all groups. As in the white matter, the mean GFAP mRNA levels were decreased in individuals with schizophrenia and bipolar disorder as compared with the unaffected controls, however the difference failed to reach statistical significance. Thus, astrocytes positive for GFAP may contribute to the decrease in glial density previously described in subjects with major mental illness, however the relative contribution of astrocytes may vary with diagnosis.

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THE LANCET • Vol 363 • January 3, 2004 • www.thelancet.com 37 30 Gorovits R, Avidan N, Avisar N, Shaked I, Vardimon L. Glutamine synthetase protects against neuronal degeneration in injured retinal tissue. Proc Natl Acad Sci USA 1997; 94: 7024–29. 31 Szegedy L. Enzyme histochemical studies in the rat hippocampus, cerebellar cortex and brainstem motor nuclei during methionine sulphoximine convulsions. Cell Mol Biol 1978; 23: 43–53. 32 Folbergrova J, Passonneau JV, Lowry OH, Schulz DW. Glycogen, ammonia and related metabolites in the brain during seizures evoked by methionine sulphoximine. J Neurochem 1969; 16: 191–203. 33 Laming PR, Cosby SL, O’Neill JK. Seizures in the Mongolian gerbil are related to a deficiency in cerebral glutamine synthetase. Comp Biochem Physiol C 1989; 94: 399–404. 34 Walz W, Lang MK. Immunocytochemical evidence for a distinct GFAP-negative subpopulation of astrocytes in the adult rat hippocampus. Neurosci Lett 1998; 257: 127–30. 35 Condorelli DF, Dell’Albani P, Kaczmarek L, et al. Glial fibrillary acidic protein messenger RNA and glutamine synthetase activity after nervous system injury. J Neurosci Res 1990; 26: 251–57. 36 Blondet B, Hantaz-Ambroise D, Ait-Ikhlef A, Cambier D, Murawsky M, Rieger F. Astrocytosis in wobbler mouse spinal cord involves a population of astrocytes which is glutamine synthetasenegative. Neurosci Lett 1995; 183: 179–82. 37 Derouiche A, Heimrich B, Frotscher M. Loss of layer-specific astrocytic glutamine synthetase immunoreactivity in slice cultures of hippocampus. Eur J Neurosci 1993; 5: 122–27. 38 Jackson MJ, Zielke HR, Max SR. Effect of dibutyryl cyclic AMP and dexamethasone on glutamine synthetase gene expression in rat astrocytes in culture. Neurochem Res 1995; 20: 201–07. 39 Stanimirovic DB, Ball R, Small DL, Muruganandam A. Developmental regulation of glutamate transporters and glutamine synthetase activity in astrocyte cultures differentiated in vitro. Int J Dev Neurosci 1999; 17: 173–84. 40 Vardimon L, Ben-Dror I, Avisar N, Oren A, Shiftan L. Glucocorticoid control of glial gene expression. J Neurobiol 1999; 40: 513–27. 41 Beer J, Mielke K, Zipp M, Zimmermann M, Herdegen T. Expression of c-jun, junB, c-fos, fra-1 and fra-2 mRNA in the rat brain following seizure activity and axotomy. Brain Res 1998; 794: 255–66. 42 Huang TL, O’Banion MK. Interleukin-1 beta and tumor necrosis factor-alpha suppress dexamethasone induction of glutamine synthetase in primary mouse astrocytes. J Neurochem 1998; 71: 1436–42. 43 Kruchkova Y, Ben-Dror I, Herschkovitz A, David M, Yayon A, Vardimon L. Basic fibroblast growth factor: a potential inhibitor of glutamine synthetase expression in injured neural tissue. J Neurochem 2001; 77: 1641–49. 44 Liu Z, Holmes GL. Basic fibroblast growth factor-induced seizures in rats. Neurosci Lett 1997; 233: 85–88.

Neuronal injury-induced expression and release of apolipoprotein E in mixed neuron/glia co-cultures: nuclear factor kappaB inhibitors reduce basal and lesion-induced secretion of apolipoprotein E.

In order to better delineate the intracellular signaling pathways underlying glial apolipoprotein E (apoE) expression and release, we have characterized an in vitro model of induction of glial apoE production induced by neuronal death. Exposure of mixed fetal cortical neuron/glia co-cultures to the neurotoxin N-methyl-D-aspartate results in increased apoE expression and release in a time- and concentration-dependent manner. Increased expression of apoE messenger RNA precedes the increase in intracellular apoE, followed by accumulation of the holoprotein in the culture medium. Neuronal injury induced by N-methyl-D-aspartate is accompanied by a reactive astrogliosis as measured by an increase in glial fibrillary acidic protein messenger RNA and protein at 48 and 72h post-lesion, respectively. A similar microgliosis was observed using the microglial marker ED-1. Neuronal injury-induced glial apoE secretion is attenuated by the nuclear factor kappaB inhibitors, aspirin, Bay 11-7082 and MG-132, suggesting that this transcription factor is involved in both constitutive and induced glial apoE expression. The present data show that up-regulation of apoE is an early event in the glial activation triggered by neurodegeneration in vitro and that activation of nuclear factor kappaB directly or indirectly mediates the increase in apoE expression.

The mosaic of brain glial hyperactivity during normal ageing and its attenuation by food restriction

Food restriction of adult rodents increases lifespan, with commensurate attenuation of age-related pathological lesions in many organs, as well as attenuation of normal ageing changes that are distinct from gross lesions. Previous work showed that chronic food restriction attenuated age-associated astrocyte and microglial hyperactivity in the hippocampal hilus, as measured by expression of glial fibrillary acidic protein and major histocompatibility complex II antigen (OX6). Here, we examined other markers of astrocyte and microglial activation in gray and white matter regions of ad libitum-fed (Brown Norway×Fischer 344) F 1 male rats aged three and 24 months and chronic food-restricted rats aged 24 months. In situ hybridization and immunohistochemical techniques evaluated glial expression of glial fibrillary acidic protein, apolipoprotein E, apolipoprotein J (clusterin), heme oxygenase-1, complement 3 receptor (OX42), OX6 and transforming growth factor- β1. All markers were elevated in the corpus callosum during ageing and were attenuated by food restriction, but other regions showed marked dissociation of the extent and direction of changes. Astrocytic activation, as measured with glial fibrillary acidic protein expression (coding and intron-containing RNA, immunoreactivity), increased with age in the corpus callosum, basal ganglia and hippocampus. Generally, food restriction attenuated the age-related increase in glial fibrillary acidic protein messenger RNA and immunoreactivity. Food restriction also reduced the age-related increase in apolipoprotein J and E messenger RNA and heme oxygenase-1 immunoreactivity in the basal ganglia and corpus callosum. However, astrocytes in the hilus of the hippocampus showed an age-related decrease in apolipoprotein J and E messenger RNA, which was further intensified by food restriction. The age-associated microglial activation measured by OX6 and OX42 immunoreactivity was reduced by food restriction in most subregions. The localized subsets of glial age changes and effects of food restriction comprise a mosaic of ageing consistent with the regional heterogeneity of ageing changes reported by others. In particular, age has a differential effect on astrocytic and microglial hyperactivity in gray versus white matter areas. The evident mosaic of glial ageing and responses to food restriction suggests that multiple mechanisms are at work during ageing.

Astrocytes and oligodendrocytes reactions after a total section of the rat spinal cord

Regeneration after an injury in the Central Nervous System is dependent on intrinsic and extrinsic factors. Among the latter are the reactions of glial cells. Using the model of total section of adult rat spinal cord, we have studied the spatial and temporal responses of astrocytes and oligodendrocytes to the lesion of spinal cord axons. We studied at molecular and cellular levels the specific markers GFAP (glial fibrillary acidic protein) for the astrocytes, CNP (2′-3′ cyclic 3′ nucleotide phosphodiesterase) which is principally expressed by immature oligodendrocytes, and MBP (myelin basic protein) implicated later in the myelin compaction, and which is more specific of mature oligodendrocytes. After injury, all astrocytes, but more markedly those of the grey matter, reacted by an increase of GFAP messenger and protein. This increase was very rapid for messenger, and peaked at 3 days. This increase was more protracted for the protein and persisted after 3 weeks. Messenger increase is more marked and more protracted below than above the lesion. Oligodendrocytes also reacted quickly by an increase of CNP and MBP messengers. For CNP, both messenger and protein increased rapidly and returned to control level after 1 week. MBP showed the same time course of changes, with lower and slower decrease above the lesion. Counts of oligodendrocytes showed that the percentage of the less mature form (light oligodendrocytes) increased dramatically above and below the lesion. After 1 week, above the lesion, this percentage was well below that of the control, whereas below the lesion, it reverted to control value. These results indicate that, following a lesion, astrocytes react quickly and intensely, but more so below the lesion; oligodendrocytes resume a sequence of maturation which is eventually completed above the lesion where remyelinisation can occur and which is prematurely interrupted below the lesion. However, intact oligodendrocytes persist below the lesion, where they constitute a potential for remyelinisation of regenerated and/or transplanted axons.

Temporal changes in glial fibrillary acidic protein messenger RNA and [ 3H]PK11195 binding in relation to imidazoline-I 2-receptor and α2-adrenoceptor binding in the hippocampus following transient global forebrain ischaemia in the rat

Immunohistochemical studies have demonstrated that following global forebrain ischaemia the selective neuronal loss that occurs in the CA1 pyramidal cell layer of the hippocampus is accompanied by a reactive astrocytosis, characterized by increases in glial fibrillary acidic protein, and activation of microglia. In this study the spatial changes in glial fibrillary acidic protein messenger RNA levels in the hippocampus have been mapped four, eight, 12, 16 and 20 days following 10 min of global forebrain ischaemia in the rat and related to changes in [ 3H]PK11195 binding to peripheral benzodiazepine receptors, a putative marker of activated microglia. Recent studies have suggested that the imidazoline-I 2-receptor, one of a class of non-adrenergic receptors related to, but structurally and functionally distinct from α 2-adrenoceptors, may have a functional role in controlling the expression of glial fibrillary acidic protein. To explore this possibility further we have also mapped changes in imidazoline-I 2-receptor and α 2-adrenoceptor binding sites. Following transient ischaemia there was a marked, biphasic increase in glial fibrillary acidic protein messenger RNA levels throughout the vulnerable CA1 region of the hippocampus, peaking four days after ischaemia and then increasing gradually during the remainder of the study period. There was also a sustained increase in [ 3H]PK11195 binding, however, in contrast to the initial increase in glial fibrillary acidic protein messenger RNA levels that peaked four days after ischaemia the density of [ 3H]PK11195 binding increased rapidly in all strata of the CA1 region over the first eight days and then increased more slowly throughout days 12 to 20. Despite the marked increase in glial fibrillary acidic protein messenger RNA levels there was no concomitant alteration in imidazoline-I 2-receptor binding sites detected using the specific radioligand, [ 3H]2-(2-benzofuranyl)-2-imidazoline, although α 2-adrenoceptor binding was decreased at eight days after ischaemia and did not recover. The time course and biphasic nature of the changes in the astrocytic marker, glial fibrillary acidic protein messenger RNA, in the hippocampus following ischaemia may reflect different functions of glial fibrillary acidic protein-reactive astrocytes in the post-ischaemic period. Differences in temporal expression of glial fibrillary acidic protein messenger RNA and [ 3H]PK11195 binding support the proposed localization of peripheral benzodiazepine receptors on activated microglia, as distinct from reactive astrocytes. There was no evidence in the present study that imidazoline-I 2-receptors are functionally linked to glial fibrillary acidic protein expression as the reactive astrocytosis in the hippocampus following ischaemia was not associated with changes in imidazoline-I 2-receptor binding site density.

Sexual dimorphism and sex steroid modulation of glial fibrillary acidic protein messenger RNA and immunoreactivity levels in the rat hypothalamus

By using the techniques of in situ hybridization histochemistry and immunocytochemistry, we have found that both glial fibrillary acidic protein messenger RNA levels and glial fibrillary acidic protein immunoreactive surface density in the arcuate nucleus and median eminence are modulated by both the neonatal and adult sex steroid environments. No effect was seen on the number of immunoreactive glia. Intact adult males had significantly higher glial fibrillary acidic protein messenger RNA levels and glial fibrillary acidic protein immunoreactive surface density than females. Both adult and neonatal castration of male animals significantly reduced glial fibrillary acidic protein messenger RNA levels and glial fibrillary acidic protein immunoreactive surface density. Neonatal and adult testosterone treatment increased both of these parameters in both sexes; however, there was no additive effect of the steroid treatments. Glial cells are involved in the proliferation, survival, migration and maturation of neurons, as well as in the modulation of synaptic connectivity, and therefore it follows that hormonal modulation of glia may mediate some of the known steroid effects on neurons. The data reported here show that astroglia are significantly influenced by both the neonatal and adult sex steroid environments and suggest that some of the steroid effects on neurons during both of these developmental periods may be mediated, at least in part, through modulation of glial cells.

Transcriptional regulation of glial fibrillary acidic protein by corticosterone in rat astrocytes in vitro is influenced by the duration of time in culture and by astrocyte-neuron interactions.

In the rat hippocampus and cortex, the transcription of glial fibrillary acidic protein (GFAP), an astrocyte intermediate filament protein, is inhibited by glucocorticoids. The present study examined the regulation of GFAP expression by glucocorticoids in astrocytes in vitro. Corticosterone (CORT) increased GFAP messenger RNA, protein, and transcription rates in cultured primary neonatal astrocytes, responses opposite the GFAP responses to CORT in vivo. The direction of GFAP regulation by corticosterone in vitro is reversed by coculture with neurons or by extended culture for 3 months. The switch in the direction of GFAP regulation by CORT during prolonged culture is associated with a 3-fold increased prevalence of type II glucocorticoid receptor (GR). These findings were corroborated with a promoter construct that contained 1.9 kilobases of 5'-up-stream rat GFAP DNA with a luciferase reporter. Thus, the direction of GFAP transcription to CORT is subject to the postreplicative time in culture and to interactions with neurons, in which 5'-up-stream sequences contain sufficient information to mediate the switch in the direction of the response to CORT. This in vitro model may be used to analyze how interactions of astrocytes with neurons or other cell types influence the hormonal regulation of GFAP.

Transforming growth factor- β1 induces neuronal and astrocyte genes: Tubulin α1, glial fibrillary acidic protein and clusterin

Transforming growth factor-β1 was studied as a possible regulator of messenger RNAs in astrocytes and neurons that increase after hippocampal deafferentation by perforant path transection: tubulin α1, clusterin and glial fibrillary acidic protein messenger RNA. Because transforming growth factor-β1 messenger RNA is increased after this lesion, we examined which messenger RNA lesion responses could be induced by transforming growth factor-β1 alone. Porcine transforming growth factor-β1 infused into the lateral ventricle elevated the messenger RNAs for tubulin α1, clusterin and glial fibrillary acidic protein 24 h after infusion in the ipsilateral hippocampus. As assayed by nuclear run-on, the transcription of glial fibrillary acidic protein RNA was increased in the ipsilateral hippocampus after perforant path transection and in primary rat astrocyte cultures by transforming growth factor-β1. In contrast, transforming growth factor-β1 did not change apolipoprotein-E messenger RNA or transcription, or growth associated protein-43 messenger RNA levels. We conclude that transforming growth factor-β1 increases subsets of neuronal and astrocyte messenger RNAs coding for cytoskeletal proteins that are also elevated in response to experimental lesions and Alzheimer's disease. This suggests that transforming growth factor-β1 might be a local organizing factor of neuronal and astrocyte responses to brain injury.

Gonadal steroids regulate the expression of glial fibrillary acidic protein in the adult male rat hippocampus

This study demonstrates that gonadal steroids (estradiol, testosterone, dihydrotestosterone) can regulate the expression of glial fibrillary acidic protein in the adult male rat brain. Previously, we showed that castration of adult male rats increased glial fibrillary acidic protein messenger RNA in the hippocampus and that this increase was additive with the increase induced by deafferenting entorhinal cortex lesions [ Day el al. (1990) Molec. Endocr. 4, 1995–2002]. We extended these effects of castration and entorhinal cortex lesion to glial fibrillary acidic protein, using immunoassays. Furthermore, we found regional differences in responses to castration and sex steroid replacement. In the hippocampus, glial fibrillary acidic protein expression was enhanced by castration and inhibited by sex steriods. In contrast, hypothalamic glial fibrillary acidic protein expression was inhibited by castration. Similar regional differences were also shown for astrocyte glial fibrillary acidic protein distribution by immunocytochemistry. The regional specificity of glial fibrillary acidic protein expression after castration and sex steroid replacement is pertinent to the role of astrocytes in synaptic plasticity in unlesioned adults as well as in responses to lesions where the steroid milieu has been shown to influence sprouting.

Glial fibrillary acidic protein messenger RNA and glutamine synthetase activity after nervous system injury

The level of the mRNA for glial fibrillary acidic protein (GFAP), the major protein of the intermediate filaments of astroglial cells, and the activity of glutamine synthetase (GS), an enzyme selectively localized in astrocytes, were measured at different times after a unilateral mechanical lesion in the rat cerebral cortex. A rapid and early increase (6 hours post-lesion) in GFAP mRNA was observed; GFAP mRNA level reached a peak at 1-3 days and then decreased. Moreover, an astrocytic activation in cortical zones far from the injury site and in the contralateral hemisphere was detected. No change of GS activity was observed in the same model of brain injury, showing that this astroglial marker is not modified during the reactive gliosis obtained with this experimental model. GFAP mRNA has also been detected in the rat sciatic nerve; however, its level was not modified after nerve transection, suggesting a different regulation of GFAP expression in the peripheral nervous system.