Objective: The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells to ischemia. However, the mechanisms of such vulnerability are not ...fully understood. We previously reported that spinal motor neurons might be lost as a result of programmed cell death and investigated a possible mechanism of neuronal death by means of immunohistochemical analysis for CPP32 (caspase3) and serine-threonine kinase (Akt). Methods: We used a rabbit spinal cord ischemia model with use of a balloon catheter. The spinal cord was removed at 8 hours or 1, 2, or 7 days after 15 minutes of transient ischemia, and histologic changes were studied with hematoxylin and eosin staining. Western blot analysis for Akt and caspase3, temporal profiles of Akt and caspase3 immunoreactivity, and double-label fluorescence immunocytochemical studies were performed. Results: The majority of motor neurons were preserved until 2 days but were selectively lost at 7 days of reperfusion. Western blot analysis revealed no immunoreactivity for Akt and caspase3 in the sham-operated spinal cords. However, such immunoreactivity became apparent at 8 hours after transient ischemia, decreased at 1 day, and returned to the baseline level at 2 days. A double-label fluorescence immunocytochemical study revealed that both Akt and caspase3 were positive at 8 hours of reperfusion in the same motor neurons, which eventually die. Conclusion: These results suggests that transient spinal cord ischemia activates both cell death and survival pathways after ischemia. The activation of Akt protein at the early stage of reperfusion might be one of the factors responsible for the delay in neuronal death after spinal cord ischemia.
J Thorac Cardiovasc Surg 2003;125:370-7
Objective
Early‐onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH)/ataxia with oculomotor apraxia type 1 (AOA1) is an autosomal recessive form of cerebellar ataxia. The causative ...protein for EAOH/AOA1, aprataxin (APTX), interacts with X‐ray repair cross‐complementing 1 (XRCC1), a scaffold DNA repair protein for single‐strand breaks (SSBs). The goal of this study was to prove the functional involvement of APTX in SSB repair (SSBR).
Methods
We visualized the SSBR process with a recently developed laser irradiation system that allows real‐time observation of SSBR proteins and with a local ultraviolet‐irradiation system using a XPA‐UVDE cell line that repairs DNA lesions exclusively via SSBR. APTX was knocked down using small interference RNA in the cells. Oxidative stress–induced DNA damage and cell death were assessed in EAOH fibroblasts and cerebellum.
Results
Our systems showed the XRCC1‐dependent recruitment of APTX to SSBs. SSBR was impaired in APTX‐knocked‐down cells. Oxidative stress in EAOH fibroblasts readily induced SSBs and cell death, which were blocked by antioxidants. Accumulated oxidative DNA damage was confirmed in EAOH cerebellum.
Interpretation
This study provides the first direct evidence for the functional involvement of APTX in SSBR and in vivo DNA damage in EAOH/AOA1, and suggests a benefit of antioxidant treatment. Ann Neurol 2007;61:162–174
Mammalian sialidases are key enzymes in the degradation of glycoconjugates. Neu4L sialidase is localized to mitochondria and specifically expressed in brain. To elucidate the pathophysiological roles ...of Neu4L in the nervous system, we investigated the possible involvement of Neu4L in the apoptotic neurodegeneration under the existence of catechol metabolites generated by tyrosinase. We demonstrated that: (i) the expression level of Neu4L was dramatically decreased prior to apoptosis; (ii) the apoptotic phenotype was characterized by cytochrome
c release into cytosol concomitant with the trafficking of ganglioside GD3 to mitochondria; and (iii) the inhibitor of glucosylceramide synthase partially recovered cell viability. Neu4L and its substrate GD3 may act as key molecules in the mitochondrial apoptotic pathway in neuronal cells.
Abstract Hyposmia in Parkinson's disease (PD) was evaluated by using neuroimaging techniques. It is well known that olfactory impairments are one of the cardinal non-motor symptoms in PD. However, ...all smell tests used in previous studies depend on subjective answers by examinees and on sniffing of odorants, the latter of which may be impaired in PD as a consequence of motor impairments. We developed an fMRI system, which can visualize brain activation by olfactory stimuli during natural breathing. Although 7 age-matched controls demonstrated significant activations in various brain areas including precentral gyrus (BA6/6) and middle temporal gyrus (BA19/39) by the odorant stimuli, 9 patients with PD showed little activations by the same stimuli. These data suggest that the olfactory dysfunction in PD is not a simple reflection of impaired sniffing. Recent epidemiological studies demonstrate that the olfactory impairments may precede the onset of motor symptoms. Moreover, several pathological studies suggest that amygdala is one of the most frequently affected regions and is closely related to hyposmia in PD. Further brain imaging studies of hyposmia will shed light on the early pathological changes in PD.
The objective of this study was to verify the hypothesis that variation of the serotonin transporter gene promoter region (5-HTTLPR) is associated with sensitivity to stress.
Genotyping of 5-HTTLPR ...and evaluation of emotional states were performed on 194 participants. Participants' emotional states were evaluated using the Perceived-Stress Scale (PSS), the State-Trait Anxiety Inventory (STAI), and the Self-rating Depression Scale (SDS).
There was significant Gender×Genotype interaction in STAI (state,
P<.05; trait,
P<.05). Females with the
l/s genotype showed higher anxiety than those with the
s/s genotype in both state and trait anxiety. Oppositely, males with the
s/s genotype showed higher anxiety than those with the
l/s genotype.
On all emotional scales, females with the
l/s genotype showed high scores, contrary to males with the same genotype. Therefore, our results suggest that 5-HTTLPR
l allele may be one pathway that activates negative emotion in females but acts contrary in males.
Multiple sclerosis (MS) is a chronic immune-mediated inflammatory demyelinating disease of the central nervous system. Interferon-β (IFN-β) has been used as the first line therapy for MS treatment in ...Japan, but patients treated with IFN-β may develop antibodies, known as neutralizing antibodies (NAbs), which abrogate its therapeutic effects. Intramuscular IFN-β 1a and subcutaneous IFN-β 1b are currently available in Japan, but large-scale studies evaluating the prevalence and clinical implications of NAbs against these IFN-β preparations in MS patients have only been performed in Caucasian populations. NAbs positivity has been reported to be associated with HLA-DRB1 alleles, suggesting that the positivity might differ among populations with distinct genetic backgrounds. Clinical information and sera were collected from 229 consecutive MS patients treated with IFN-β in 4 centers in Japan. Sera were tested for NAbs using a luciferase reporter gene assay. In total, 5.2% of IFN-β-1a-treated patients (4/77) and 30.3% of IFN-β-1b-treated patients (46/152) were positive for Nabs. The frequency of NAbs was highest in patients treated for 13 to 24 months. Clinical relapse and contrast-enhancing lesions in the magnetic resonance imaging increased together with NAbs titers in this group. In conclusion, the prevalence of NAbs in Japanese MS patients is similar to that in Caucasian populations and is associated with an increase in disease activity. Therefore, routine NAbs testing is recommended also in Asian populations to ensure the early identification of patients who would benefit from a change in therapy.
Abstract There are two distinct phenotypes of multiple sclerosis (MS) in Asians, optic-spinal MS (OSMS) and conventional MS (CMS). In 2004, we performed the fourth nationwide epidemiological survey ...of MS. The epidemiological features were reported elsewhere; here we report the characteristic features of patients with each MS phenotype, classified according to the clinically estimated sites of involvement and MRI findings. Among 1493 MS patients collated, 57.7% were classified as having CMS and 16.5% were classified as having OSMS. Based on MRI findings, MS patients were further subdivided into those with OSMS with or without longitudinally extensive spinal cord lesions (LESCLs) and those with CMS with or without LESCLs. Although disease duration did not differ significantly among the four groups, EDSS scores were significantly higher in patients with LESCLs than in those without LESCLs, irrespective of OSMS or CMS phenotype. Similar trends were found for the frequencies of bilateral visual loss, transverse myelitis, and marked CSF pleocytosis and neutrophilia. Increased IgG index, brain lesions fulfilling the Barkhof criteria and secondary progression were more commonly found in CMS patients than in OSMS patients, while negative brain MRIs were more commonly encountered in OSMS patients than CMS patients, irrespective of the presence of LESCLs. These findings suggest that demographic features not only vary based on CMS or OSMS phenotype, but also with the presence or absence of LESCLs, and that nonetheless, these four phenotypes constitute a continuum.
Ganglioside sialidases have been implicated in neuronal differentiation processes, including neurite outgrowth. To understand further the roles and regulation mechanisms of the sialidase in neuronal ...systems, we have cloned mouse ganglioside sialidase cDNA and observed its expression in Neuro2a cell differentiation. A 3339-base pair cDNA, cloned based on the sequence information of previously cloned enzymes, encodes 418 amino acids containing three Asp boxes characteristic of sialidases. Northern blot analysis revealed a 3.4-kilobase transcript expressed highly in heart but also in several other tissues including brain. In situ hybridization of mouse brain demonstrated the mRNA to be present in the cerebral cortex, as well as in the granule cell layer, Purkinje cells, and deep cerebellar nucleus of the cerebellum. Transient expression of the cDNA in COS-1 cells resulted in over 300-fold increase in sialidase activity toward gangliosides compared with the control level, with a preference for ganglioside substrate. During 5-bromodeoxyuridine-induced Neuro2a cell differentiation, the expression of the sialidase was increased as assessed by activity assays and quantitative reverse transcription-polymerase chain reaction analyses. Stable transfection of the sialidase in Neuro2a cells resulted in accelerated neurite arborization following 5-bromodeoxyuridine treatment, indicating the direct participation of this ganglioside sialidase in neuronal cell differentiation.
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