GluR2/3, NMDAε1 and GABA<Subscript>A</Subscript> receptors in Creutzfeldt-Jakob disease

The excitatory ionotropic glutamate receptors N-methyl-d-aspartate (NMDA) and -amino-3-hydro-5methyl-4-isoxazole propionic acid (AMPA) receptors, and the inhibitory -aminobutyric acid (GABA) receptors are major regulators of synaptic transmission in the central nervous system. Glutamate receptors AMPA GluR2/3 and NMDA R2A: NR2A (NMDA1), and GABA_A (GABA_A R1) receptors were examined by immunohistochemistry in the cerebral cortex (frontal cortex) entorhinal cortex, hippocampus and cerebellar cortex in nine patients with sporadic Creutzfeldt-Jakob disease (CJD) and eight age-matched controls obtained 3–8 h after death. All patients with CJD showed methionine/methionine in codon 129 of the prion protein gene. Decreased GluR2/3 immunoreactivity was found in the frontal cortex, entorhinal cortex and Purkinje cells; reduced NMDA1 immunoreactivity was found in the frontal cortex, entorhinal cortex, and molecular and granular cell layers of the cerebellum. Decreased GluR2/3 and NMDA1 immunoreactivity was also observed in the molecular layer of the dentate gyrus, but not in the hippocampus proper in cases with hippocampal involvement. GABA_A R1 expression was markedly decreased in the granular cell layer of the cerebellum in CJD. Decreased GluR2/3 and NMDA1 expression correlated with prion protein deposition, neuron loss and spongiform degeneration in the cerebral cortex in every case. However, reduced GluR2/3 immunoreactivity in Purkinje cells was apparently independent of these parameters. In contrast to ionotropic glutamate receptors, GABA_A R1 immunoreactivity was moderately increased in the frontal cortex, entorhinal cortex and molecular layer of the cerebellum in CJD. The present results show marked and selective abnormalities in the expression of crucial neurotransmitter receptors in CJD, ionotropic glutamate receptors being more severely affected than ionotropic GABA receptors. These findings stress selective vulnerability of glutamate receptors versus GABA receptors in CJD.     

Changes in the mRNA Levels of α<Subscript>2A</Subscript> and α<Subscript>2C</Subscript> Adrenergic Receptors in Rat Models of Parkinson’s Disease and <Emphasis Type="SmallCaps">l</Emphasis>-DOPA-Induced Dyskinesia

The changes in the mRNA levels of α_2A and α_2C adrenoceptors were investigated in unilateral 6-OHDA-lesioned rat model of Parkinson’s disease and l-DOPA-induced dyskinesia using in situ hybridization. In the untreated 6-OHDA-lesioned rats, α_2A expression was elevated in the locus coeruleus (160 ± 8% and 142 ± 8% in lesioned and unlesioned sides compared to the comparable side in sham-operated rats). Following long-term (21 days, twice daily) treatment with l-DOPA (25 mg/kg l-DOPA methyl ester plus benserazide 6.25 mg/kg) in 6-OHDA-lesioned rats, levels of α_2A adrenoceptor mRNA in the locus coeruleus were decreased, compared to the 6-OHDA-lesioned rats, returning to the levels of α_2A mRNA in the sham-operated rats. α_2A adrenoceptor expression was not changed in other brain regions in any treatment group. There was no change in α_2C expression in the rostral or caudal striatum in which the highest density of α_2C mRNA is present. In conclusion, the data presented in this study demonstrate an increase in α_2A adrenoceptor mRNA in the locus coeruleus in the 6-OHDA-lesioned rat model of Parkinson’s disease. In addition, the data show that repeated treatment with l-DOPA in 6-OHDA-lesioned rats, which induces dyskinesia, restores α_2A mRNA levels. These changes of α_2A mRNA expression, observed in the locus coeruleus, might be of importance to basal ganglia transmission and motor function.     

The Neuropeptide Orexin-A Inhibits the GABA<Subscript>A</Subscript> Receptor by PKC and Ca<Superscript>2+</Superscript>/CaMKII-Dependent Phosphorylation of Its β<Subscript>1</Subscript> Subunit

Orexin-A and orexin-B (Ox-A, Ox-B) are neuropeptides produced by a small number of neurons that originate in the hypothalamus and project widely in the brain. Only discovered in 1998, the orexins are already known to regulate several behaviours. Most prominently, they help to stabilise the waking state, a role with demonstrated significance in the clinical management of narcolepsy and insomnia. Orexins bind to G-protein-coupled receptors (predominantly postsynaptic) of two subtypes, OX₁R and OX₂R. The primary effect of Ox-OXR binding is a direct depolarising influence mediated by cell membrane cation channels, but a wide variety of secondary effects, both pre- and postsynaptic, are also emerging. Given that inhibitory GABAergic neurons also influence orexin-regulated behaviours, crosstalk between the two systems is expected, but at the cellular level, little is known and possible mechanisms remain unidentified. Here, we have used an expression system approach to examine the feasibility, and nature, of possible postsynaptic crosstalk between Ox-A and the GABA_A receptor (GABA_AR), the brain’s main inhibitory neuroreceptor. When HEK293 cells transfected with OX₁R and the α₁, β₁, and γ_2S subunits of GABA_AR were exposed to Ox-A, GABA-induced currents were inhibited, in a calcium-dependent manner. This inhibition was associated with increased phosphorylation of the β₁ subunit of GABA_AR, and the inhibition could itself be attenuated by (1) kinase inhibitors (of protein kinase C and CaM kinase II) and (2) the mutation, to alanine, of serine 409 of the β₁ subunit, a site previously identified in phosphorylation-dependent regulation in other pathways. These results are the first to directly support the feasibility of postsynaptic crosstalk between Ox-A and GABA_AR, indicating a process in which Ox-A could promote phosphorylation of the β₁ subunit, reducing the GABA-induced, hyperpolarising current. In this model, Ox-A/GABA_AR crosstalk would cause the depolarising influence of Ox-A to be boosted, a type of positive feedback that could, for example, facilitate the ability to abruptly awake.     

Serum α<Subscript>1</Subscript>-antitrypsin level and phenotype associated with familial moyamoya disease

Background Obstructive vascular lesions at the terminal portion of the internal carotid arteries are thought to be the primary and essential lesions in moyamoya disease. The etiology remains unknown. To detect possible mediators of the thickened intima of moyamoya disease, we measured serum alpha-1-antitrypsin (1-AT) levels and characterized the phenotype of patients with familial moyamoya disease.Patients and methods Fifty-six individuals were examined, including 29 patients with moyamoya disease from 14 families. Serum 1-AT levels were analyzed by electroimmunoassay and genomic phenotype by isoelectric focusing.Results All individuals had a normal 1-AT phenotype. The average serum 1-AT level in moyamoya disease patients was significantly higher than that of normal individuals, although both were within the normal range.Conclusions These findings suggest that serum 1-AT level may be a marker, rather than an etiologic factor, indicating the progression of moyamoya disease.     

Allosteric Modulator Desformylflustrabromine Relieves the Inhibition of α2β2 and α4β2 Nicotinic Acetylcholine Receptors by β-Amyloid<Subscript>1–42</Subscript> Peptide

Nicotinic acetylcholine receptors (nAChRs) are pentameric transmembrane proteins that belong to the cys-loop ligand-gated ion channel family. These receptors are widely expressed in the brain and implicated in the pathophysiology of many neurological conditions, including Alzheimer’s disease (AD), where typical symptoms include the loss of cognitive function and dementia. The presence of extracellular neuritic plaques composed of β amyloid (Aβ_1–42) peptide is a characteristic feature of AD. Desformylflustrabromine (dFBr) is a positive allosteric modulator (PAM) for α4β2 nAChRs since it increases peak ACh responses without inducing a response on its own. Previously, the effect of dFBr on the α2β2 nAChR subtype was not known. The action of dFBr was tested on α2β2 receptors expressed in Xenopus oocytes. It was found that dFBr is also a PAM for the α2β2 receptor. Next we tested whether dFBr had any effect on the previously known block of both the α4β2 and α2β2 receptors by Aβ_1–42. We found that the functional blockade of ACh-induced currents in oocytes expressing α4β2 and α2β2 receptors by Aβ_1–42 was prevented by dFBr. We conclude that dFBr is a positive allosteric modulator for both α4β2 and α2β2 subtypes of nAChRs and that it also relieves the blockade of these receptors by Aβ_1–42. This study demonstrates that PAMs for the non-α7 nAChRs have the potential to develop into clinically applicable drugs for AD and other disorders.     

Interaction Between Ca<Subscript>v</Subscript>2.1α<Subscript>1</Subscript> and CaMKII in Ca<Subscript>v</Subscript>2.1α<Subscript>1</Subscript> Mutant Mice, <Emphasis Type="Italic">Rolling Nagoya</Emphasis>

It has been reported earlier that interactions between Ca_v2.1α₁ and calcium/calmodulin-dependent protein kinase II (CaMKII) in the presynaptic fraction and between the NMDA receptor subunit NR2B and CaMKII in the postsynaptic density (PSD) fraction are important for neuronal function. Ca_v2.1α₁, CaMKII, and NR2B are predominantly expressed in the hippocampus. To examine the above interactions and CaMKII activity in the hippocampal presynapse and PSD of Rolling Nagoya mice carrying a mutation in Ca_v2.1α₁ subunit, we performed immunoprecipitation and Western blot analyses. In the presynapse, the interaction between Ca_v2.1α₁ and CaMKII and the phosphorylation of CaMKII (at Thr286) and its substrate Synapsin I (at Ser603) were decreased in mutant mice compared to wild-type mice. In the PSD, a similar pattern was observed for the interaction between NR2B and CaMKII and the phosphorylation of CaMKII (at Thr286) and its substrate AMPA receptor subunit glutamate receptor 1 (at Ser831) between mutant and wild-type mice. Our data indicate that disruption of the interaction between Ca_v2.1α₁ and CaMKII may down-regulate presynaptic CaMKII activity and that Rolling Nagoya mice would be a useful model for examining presynaptic function.     

Platelet phospholipase A<Subscript>2</Subscript> activity in patients with Alzheimer’s disease,vascular dementia and ischemic stroke

Summary Phospholipase A₂ (E.C. 3.1.1.4, PLA₂) plays an essential role in metabolism of membrane phospholipids, it is related to inflammatory reactions, secretion of amyloid precursor protein and activation of NMDA receptor after ischemia. In the present study we investigated PLA₂ activity in platelets from 37 Alzheimer’s disease (AD) patients, 32 vascular dementia (VaD) patients and 32 individuals with ischemic stroke as compared to 27 healthy elderly controls. PLA₂ activity was determined using radiometric assay. Mean platelet PLA₂ activity was increased in individuals with Alzheimer’s disease (p < 0.001). In VaD group the enzyme activity was between the values in AD and controls, these differences being significant from both groups. In the group of patients with ischemic stroke mean PLA₂ activity was higher either 48 h after the stroke or 7 days later (in both cases p < 0.001). The results may be particularly interesting in light of the fact, that inhibitors of PLA₂ activity are known.     

Downregulation of GABAA Receptor Protein Subunits α6, β2, δ, ε, γ2, θ, and ρ2 in Superior Frontal Cortex of Subjects with Autism

We measured protein and mRNA levels for nine gamma-aminobutyric acid A (GABA_A) receptor subunits in three brain regions (cerebellum, superior frontal cortex, and parietal cortex) in subjects with autism versus matched controls. We observed changes in mRNA for a number of GABA_A and GABA_B subunits and overall reduced protein expression for GABA_A receptor alpha 6 (GABRα6), GABA_A receptor beta 2 (GABRβ2), GABA_A receptor delta (GABRδ), GABA_A receptor epsilon (GABRε), GABA_A receptor gamma 2 (GABRγ2), GABA_A receptor theta (GABRθ), and GABA_A receptor rho 2 (GABRρ2) in superior frontal cortex from subjects with autism. Our data demonstrate systematic changes in GABA_A&B subunit expression in brains of subjects with autism, which may help explain the presence of cognitive abnormalities in subjects with autism.     

Bilateral Olfactory Mucosa Damage Induces the Disappearance of Olfactory Glomerulus and Reduces the Expression of Extrasynaptic α5GABA<Subscript>A</Subscript>Rs in the Hippocampus in Early Postnatal Sprague Dawley Rats

Chloroform-induced olfactory mucosal degeneration has been reported in adult rats following gavage. We used fixed-point chloroform infusions on different postnatal days (PNDs) to investigate the effects of early olfactory bilateral deprivation on the main olfactory bulbs in Sprague Dawley rats. The experimental groups included rats infused with chloroform (5 μl) or saline (sham, 5 μl) on PNDs 3 and 8, and rats not receiving infusions (control) (n?=?6 in all groups). Rats receiving chloroform on PND 3 showed significant hypoevolutism when compared to those in other groups (P?<?0.05). There was a complete disappearance and a significant reduction in the size of olfactory glomeruli in the PND 3 and 8 groups, respectively, when compared to the respective sham groups. Rats receiving chloroform on PND 3 had significant memory impairment (P?<?0.01) and increased levels of learned helplessness (P?<?0.05), as measured using the Morris water maze and tail suspension tests, respectively. GABA_A receptor alpha5 subunit (α5GABA_AR) expression in hippocampal neurons was significantly lower in rats receiving chloroform on PND 3 than in rats in other groups (P?<?0.01), as measured using immunohistochemistry and polymerase chain reaction. There was thus a critical period for the preservation of regenerative ability in olfactory receptor neurons, during which damage and olfactory deprivation led to altered rhinencephalon structure and disappearance of olfactory glomeruli, which induced hypoevolutism. Olfactory deprivation after the critical period had no significant effect on olfactory receptor neuron regeneration, leading to reduced developmental and behavioral effects in Sprague Dawley rats.     

New molecular targets for antiepileptic drugs: α<Subscript>2</Subscript>δ, SV2A,and K<Subscript>v</Subscript>7/KCNQ/M potassium channels

Many currently prescribed antiepileptic drugs (AEDs) act via voltage-gated sodium channels, through effects on γ-aminobutyric acid-mediated inhibition, or via voltage-gated calcium channels. Some newer AEDs do not act via these traditional mechanisms. The molecular targets for several of these nontraditional AEDs have been defined using cellular electrophysiology and molecular approaches. Here, we describe three of these targets: α₂δ, auxiliary subunits of voltage-gated calcium channels through which the gabapentinoids gabapentin and pregabalin exert their anticonvulsant and analgesic actions; SV2A, a ubiquitous synaptic vesicle glycoprotein that may prepare vesicles for fusion and serves as the target for levetiracetam and its analog brivaracetam (which is currently in late-stage clinical development); and K_v7/KCNQ/M potassium channels that mediate the M-current, which acts a brake on repetitive firing and burst generation and serves as the target for the investigational AEDs retigabine and ICA-105665. Functionally, all of the new targets modulate neurotransmitter output at synapses, focusing attention on presynaptic terminals as critical sites of action for AEDs.     

Levels of mRNA coding for α-, β- and γ-synuclein in the brains of newborn, juvenile, and adult rats

Synucleins are proteins known for their malfunction in a group of illnesses called synucleopathies, which includes Alzheimer's and Parkinson's disease. To learn more about the role of synucleins in the CNS, we have studied levels of message coding for alpha-, beta-, and gamma-synuclein using quantitative RT-PCR. Levels of synuclein mRNAs were studied in the cerebral cortex (left and right, anterior and posterior), hippocampus, striatum, and cerebellum, obtained from 5-d-old (newborn), 1-mo (juvenile)-, and 6-, and 9-mo (adult)-old rats. The mRNA levels for all synucleins varied significantly among structures. The rank order of mRNA levels in different structures was cortex = hippocampus > striatum > cerebellum for alpha-synuclein; cortex > hippocampus = cerebellum > striatum for beta-synuclein; and hippocampus = striatum > cortex = cerebellum for gamma-synuclein. There was significant effect of age for mRNA levels for all synucleins. The dynamics of these changes were different depending on type of synuclein and brain structure. Levels of mRNA for alpha-synuclein were significantly reduced with age in all structures except hippocampus. For beta- and gamma-synuclein, levels increased significantly only in the cerebral cortex and only from 5 d to 1 mo of age. In contrast, gamma-synuclein levels in the cerebellum were very high at 5 d and significantly reduced at 1 mo of age. The revealed pattern and dynamics of changes in the levels of mRNA coding for synucleins would support the conclusion for an important role of these molecules during development and the aging process.     

Pathogenesis of chronic cluster headache and bouts: role of tryptamine,arginine metabolism and α<Subscript>1</Subscript>-agonists

The aim of this study was to explore the possible role of tryptamine in the pathogenesis of chronic cluster headache along with that of adrenaline and noradrenaline (α-agonists) together with arginine metabolism in the origin of cluster bouts. Plasma levels of tyramine, tryptamine, serotonin, 5-hydroxyindolacetic acid, noradrenalin, adrenalin and the markers of arginine metabolism such as arginine, homoarginine, citrulline, ADMA and NMMA, were measured in 23 chronic cluster headache patients (10 chronic cluster ab initio and 13 transformed from episodic cluster) and 28 control subjects. The plasma levels of tyramine, tryptamine, noradrenalin and adrenalin were found several times higher in chronic cluster headache patients compared to controls, whereas the plasma levels of arginine, homoarginine and citrulline were significantly lower. No differences were found in the plasma levels of serotonin, 5-hydroxyindolacetic, ADMA and NMMA between chronic cluster headache patients and control subjects. These results provide support for a role of tryptamine in the pathogenesis of chronic cluster headache and, in particular, in the duration of the cluster bouts. In addition, the low levels of the nitric oxide substrates together with the high levels of noradrenalin and adrenalin suggest an activation of endothelial TAAR1 receptors followed by the release of nitric oxide in the circulation that may constitute the final step of the physiopathology of cluster crisis.     

Interference of α-Synuclein Uptake by Monomeric β-Amyloid<Subscript>1–40</Subscript> and Potential Core Acting Site of the Interference

Increasing evidence suggests an important role of alpha-synuclein (α-Syn) in the pathogenesis of Parkinson’s disease (PD). The inter-neuronal spread of α-Syn via exocytosis and endocytosis has been proposed as an explanation for the neuropathological findings of PD in sub-clinical and clinical phases. Therefore, interfering the uptake of α-Syn by neurons may be an important step in slowing or modifying the propagation of the disease. The purposes of our study were to investigate if the uptake of α-Syn fibrils can be specifically interfered with monomeric β-Amyloid_1–40 (Aβ₄₀) and to characterise the core acting site of interference. Using a radioisotope-labelled uptake assay, we found an 80 % uptake reduction of α-Syn fibrils in neurons interfered with monomeric Aβ₄₀, but not β-Amyloid_1–42 (Aβ₄₂) as compared to controls. This finding was further confirmed by enzyme-linked immunosorbent assay (ELISA) with α-Syn uptake reduced from about 80 % (Aβ₄₂) to about 20 % (Aβ₄₀) relative to controls. To define the region of Aβ₄₀ peptide capable of the interference, we explored shorter peptides with less amino acid residues from both the C-terminus and N-terminus. We found that the interference effect was preserved if amino acid residue was trimmed to position 11 (from N-terminus) and 36 (from C-terminus), but dropped off significantly if residues were trimmed beyond these positions. We therefore deduced that the “core acting site” lies between amino acid residue positions 12–36. These findings suggest α-Syn uptake can be interfered with monomeric Aβ₄₀ and that the core acting site of interference might lie between amino acid residue positions 12–36.     

Insulin-Like Growth Factor-1 Alleviates Expression of Aβ<Subscript>1–40</Subscript> and α-, β-, and γ-Secretases in the Cortex and Hippocampus of APP/PS1 Double Transgenic Mice

To examine the effect of subcutaneous injection of insulin-like growth factor-1 (IGF-1) on the expression of the amyloid protein (Aβ_1–40), α-secretase (ADAM10), β-secretase (BACE1), and γ-secretase (PS1) in APP/PS1 double transgenic mice. APP/PS1 double transgenic mice and wild-type mice were divided into wild-type group, wild-type therapy group, transgenome group, and transgenic therapy group. Subcutaneous injection of IGF-1 (50 μg/kg day) was administered once daily to the wild-type therapy group and transgenic therapy group for 8 weeks, respectively. The expression of the Aβ_1–40 in the cortex and hippocampus was detected by immunohistochemistry 8 weeks after administration. The levels of Aβ_1–40, DAM10, BACE1, and PS1 were analysed by Western blot. The expression of the Aβ_1–40 in the cortex of the gene therapy group was significantly lower than that of the transgenome group (p?<?0.05). In APP/PS1 double transgenic mice, BACE1 expression was markedly higher in both the hippocampus (p?<?0.001, p?=?0.00009) and the cortex (p?=?0.001), compared to that of the wild-type mice. The treatment of IGF-1 markedly reduced ADAM10 expression in the hippocampus in both transgenic mice and wild-type mice (p?<?0.05), whereas the treatment mainly decreased BACE1 expression in transgenic mice but not in the wild-type mice (p?<?0.05). No significant differences in PS1 levels were detected in all groups. IGF decreased Aβ_1–40 over-expression in the cortex and hippocampus and might inhibit the damage induced by Aβ_1–40 in APP/PS1 double transgenic mice. Our study suggests that IGF-1 should inhibit Aβ production through α-secretase and β-secretase but not γ-secretase.     

Structure-Activity Relationships in Peptide Modulators of β-Amyloid Protein Aggregation: Variation in α,α-Disubstitution Results in Altered Aggregate Size and Morphology

Neuronal cytotoxicity observed in Alzheimer's disease (AD) is linked to the aggregation of β-amyloid peptide (Aβ) into toxic forms. Increasing evidence points to oligomeric materials as the neurotoxic species, not Aβ fibrils; disruption or inhibition of Aβ self-assembly into oligomeric or fibrillar forms remains a viable therapeutic strategy to reduce Aβ neurotoxicity. We describe the synthesis and characterization of amyloid aggregation mitigating peptides (AAMPs) whose structure is based on the Aβ "hydrophobic core" Aβ(17-20), with α,α-disubstituted amino acids (ααAAs) added into this core as potential disrupting agents of fibril self-assembly. The number, positional distribution, and side-chain functionality of ααAAs incorporated into the AAMP sequence were found to influence the resultant aggregate morphology as indicated by ex situ experiments using atomic force microscopy (AFM) and transmission electron microscopy (TEM). For instance, AAMP-5, incorporating a sterically hindered ααAA with a diisobutyl side chain in the core sequence, disrupted Aβ(1-40) fibril formation. However, AAMP-6, with a less sterically hindered ααAA with a dipropyl side chain, altered fibril morphology, producing shorter and larger sized fibrils (compared with those of Aβ(1-40)). Remarkably, ααAA-AAMPs caused disassembly of existing Aβ fibrils to produce either spherical aggregates or protofibrillar structures, suggesting the existence of equilibrium between fibrils and prefibrillar structures.     

Ovariectomy combined with amyloid β<Subscript>1-42</Subscript> impairs memory by decreasing acetylcholine release and α7nAChR Expression without induction of apoptosis in the hippocampus CA1 neurons of rats

In this study, the effect of ovariectomy and amyloid P_1-42 (Aβ_1-42)on eight-armed radial maze performance, acetylcholine (ACh) release, α7nACh receptor (α7nAChR), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) expression, and apoptosis of CA1 neurons in the dorsal hippocampus were investigated in rat. The results showed that the dorsal hippocampus of sham rats contains 136.7 ± 16.7 to 160.4 ± 21.1 fmol/μl ACh, and respective 201 ± 22.9 and 416.6 ± 66.3 expression of mRNA for α7nAChR and GAPDH. Ovariectomy alone, after 4 weeks, did not impair memory, and neither induced apoptosis nor changed the basal ACh release. On the other hand, Aβ_1-42 (600 pmol/10 μl/body/day i.c.v. for 7 days) impaired memory, an effect characterized by increased error choices and reduced (50–59%) ACh release, but only with slight apoptosis. Moreover, ovariectomy combined with Aβ_1-42 induced memory impairment characterized by decreased numbers of correct choices and increased numbers of errors. This effect was accompanied by a decrease of the basal ACh level (67%), α7nAChR mRNA expression (52%) and α7nAChR/GAPDH ratio (44%) without induction of apoptosis in the dorsal hippocampus. The high K⁺-evoked ACh release was not altered in ovariectomized rats, but was decreased by Aβ_1-42 (43%) and ovariectomy + Aβ_1-42 (80%). These results suggest that ovariectomy-induced hormonal deprivation after 4 weeks, when accompanied by Aβ_1-42 accumulation in the dorsal hippocampus, could impair memory by decreasing ACh release and α7nAChR expression without inducing apoptosis in the CA1 field of the dorsal hippocampus.     

Expression of α<Subscript>2</Subscript>-macroglobulin,neutrophil elastase,and interleukin-1α differs in early-stage and late-stage atherosclerotic lesions in the arteries of the circle of Willis

Different types of atherosclerotic (AS) lesions can be distinguished histologically and represent different stages of AS plaque development. Late-stage lesions more frequently develop complications such as plaque rupture and thrombosis with vessel occlusion than early AS lesions. To clarify whether protective, destructive, and inflammatory proteins are differentially expressed in early-stage and late-stage AS plaques we examined the proteinase inhibitor α₂-macroglobulin (A2M), the neutrophil elastase (NE)—an enzyme degrading elastin and collagen fibers—and the proinflammatory protein interleukin-1α (IL-1α) in all types of AS plaques in the arteries of the circle of Willis from 78 human autopsy cases of both genders (61–91 years of age). Paraffin sections of AS plaques were immunostained with antibodies directed against A2M, NE and IL-1α. In initial AS lesions A2M was found, whereas NE and IL-1α were absent. NE and IL-1α became detectable as soon as a significant number of macrophages occurred within AS lesions. With increasing histopathological type of AS lesions, a marked increase of the area of the plaque exhibiting NE and IL-1α was observed. The area which exhibits A2M in AS plaques, on the other hand, did not vary significantly between the different stages. Thus, our results indicate a disproportionately high increase of the destructive enzyme NE and the proinflammatory protein IL-1α in relation to A2M with the progression of the grade of AS lesions pointing to the transgression of the protective capacity of A2M by NE and IL-1α in late-stage plaques. Therefore, our findings support the hypothesis that NE-induced tissue damage in late-stage AS plaques contributes to the development of plaque rupture and subsequent thrombosis.     

Expression of GABAA α2-, β1- and ?-receptors are altered significantly in the lateral cerebellum of subjects with schizophrenia,major depression and bipolar disorder

There is abundant evidence that dysfunction of the γ-aminobutyric acid (GABA)ergic signaling system is implicated in the pathology of schizophrenia and mood disorders. Less is known about the alterations in protein expression of GABA receptor subunits in brains of subjects with schizophrenia and mood disorders. We have previously demonstrated reduced expression of GABA_B receptor subunits 1 and 2 (GABBR1 and GABBR2) in the lateral cerebella of subjects with schizophrenia, bipolar disorder and major depressive disorder. In the current study, we have expanded these studies to examine the mRNA and protein expression of 12 GABA_A subunit proteins (α1, α2, α3, α5, α6, β1, β2, β3, δ, ɛ, γ2 and γ3) in the lateral cerebella from the same set of subjects with schizophrenia (N=9–15), bipolar disorder (N=10–15) and major depression (N=12–15) versus healthy controls (N=10–15). We found significant group effects for protein levels of the α2-, β1- and ɛ-subunits across treatment groups. We also found a significant group effect for mRNA levels of the α1-subunit across treatment groups. New avenues for treatment, such as the use of neurosteroids to promote GABA modulation, could potentially ameliorate GABAergic dysfunction in these disorders.