Abstract Chronic neuropathic pain caused by peripheral nerve injury is associated with global changes in gene expression in damaged neurons. To understand the molecular mechanisms underlying ...neuropathic pain, it is essential to elucidate how nerve injury alters gene expression and how the change contributes to the development and maintenance of chronic pain. MicroRNAs are non-protein-coding RNA molecules that regulate gene expression in a wide variety of biological processes mainly at the level of translation. This study investigated the possible involvement of microRNAs in gene regulation relevant to neuropathic pain. The analyses focused on a sensory organ-specific cluster of microRNAs that includes miR-96, −182, and −183. Quantitative real-time polymerase chain reaction (qPCR) analyses confirmed that these microRNAs were highly enriched in the dorsal root ganglion (DRG) of adult rats. Using the L5 spinal nerve ligation (SNL) model of chronic neuropathic pain, we observed a significant reduction in expression of these microRNAs in injured DRG neurons compared to controls. In situ hybridization and immunohistochemical analyses revealed that these microRNAs are expressed in both myelinated (N52 positive) and unmyelinated (IB4 positive) primary afferent neurons. They also revealed that the intracellular distributions of the microRNAs in DRG neurons were dramatically altered in animals with mechanical hypersensitivity. Whereas microRNAs were uniformly distributed within the DRG soma of non-allodynic animals, they were preferentially localized to the periphery of neurons in allodynic animals. The redistribution of microRNAs was associated with changes in the distribution of the stress granule (SG) protein, T-cell intracellular antigen 1 (TIA-1). These data demonstrate that SNL induces changes in expression levels and patterns of miR-96, −182, and −183, implying their possible contribution to chronic neuropathic pain through translational regulation of pain-relevant genes. Moreover, SGs were suggested to be assembled and associated with microRNAs after SNL, which may play a role in modification of microRNA-mediated gene regulation in DRG neurons.
Background and purpose
Akinetic mutism is thought to be an appropriate therapeutic end‐point in patients with sporadic Creutzfeldt−Jakob disease (sCJD). However, prognostic factors for akinetic ...mutism are unclear and clinical signs or symptoms that precede this condition have not been defined. The goal of this study was to identify prognostic factors for akinetic mutism and to clarify the order of clinical sign and symptom development prior to its onset.
Methods
The cumulative incidence of akinetic mutism and other clinical signs and symptoms was estimated based on Japanese CJD surveillance data (455 cases) collected from 2003 to 2008. A proportional hazards model was used to identify prognostic factors for the time to onset of akinetic mutism and other clinical signs and symptoms.
Results
Periodic synchronous discharges on electroencephalography were present in the majority of cases (93.5%). The presence of psychiatric symptoms or cerebellar disturbance at sCJD diagnosis was associated with the development of akinetic mutism hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.14–1.99, and HR 2.15, 95% CI1.61–2.87, respectively. The clinical course from cerebellar disturbance to myoclonus or akinetic mutism was classified into three types: (i) direct path, (ii) path via pyramidal or extrapyramidal dysfunction and (iii) path via psychiatric symptoms or visual disturbance.
Conclusions
The presence of psychiatric symptoms or cerebellar disturbance increased the risk of akinetic mutism of sCJD cases with probable MM/MV subtypes. Also, there appear to be sequential associations in the development of certain clinical signs and symptoms of this disease.
Transient receptor potential (TRP) channels play crucial roles in sensory perception. Expression of the Drosophila painless (pain) gene, a homolog of the mammalian TRPA1/ANKTM1 gene, in the ...peripheral nervous system is required for avoidance behavior of noxious heat or wasabi. In this study, we report a novel role of the Pain TRP channel expressed in the nervous system in the sexual receptivity in Drosophila virgin females. Compared with wild‐type females, pain mutant females copulated with wild‐type males significantly earlier. Wild‐type males showed comparable courtship latency and courtship index toward wild‐type and pain mutant females. Therefore, the early copulation observed in wild‐type male and pain mutant female pairs is the result of enhanced sexual receptivity in pain mutant females. Involvement of pain in enhanced female sexual receptivity was confirmed by rescue experiments in which expression of a pain transgene in a pain mutant background restored the female sexual receptivity to the wild‐type level. Targeted expression of pain RNA interference (RNAi) in putative cholinergic or GABAergic neurons phenocopied the mutant phenotype of pain females. However, target expression of pain RNAi in dopaminergic neurons did not affect female sexual receptivity. In addition, conditional suppression of neurotransmission in putative GABAergic neurons resulted in a similar enhanced sexual receptivity. Our results suggest that Pain TRP channels expressed in cholinergic and/or GABAergic neurons are involved in female sexual receptivity.
A subset of patients with dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) demonstrates atypical clinical features and plaque formation in the brain (plaque type).
To elucidate the ...frequency and clinical features of plaque type dCJD in comparison with the non-plaque type.
We analyzed clinicopathologic findings of 66 patients who had been registered as having dCJD by the Creutzfeldt-Jakob Disease Surveillance Committee, Japan, between April 1999 and February 2006.
1) Analysis of pathologically confirmed dCJD patients (n = 23) demonstrated plaque type dCJD in 11 patients (48%). In contrast to the non-plaque type with classic CJD features, the plaque type commonly presented with ataxic gait as an initial manifestation, relatively slow progression of neurologic symptoms, and no or late occurrence of periodic sharp-wave complexes (PSWCs) on EEG. MRI, especially diffusion-weighted images, and CSF 14-3-3 protein and neuron specific enolase (NSE) showed high diagnostic sensitivities for plaque as well as non-plaque types. 2) Analysis of clinically diagnosed dCJD patients (n = 34) demonstrated that 7 patients (21%) had atypical clinical features without PSWCs, probably corresponding to plaque type dCJD.
The frequency of the plaque type in dura mater graft-associated Creutzfeldt-Jakob disease is apparently higher than previously recognized. For the clinical diagnosis of the plaque type dura mater graft-associated Creutzfeldt-Jakob disease, MRI and CSF markers would be useful, in addition to the core features, i.e., onset with ataxic gait disturbance, relatively slow progression, and no or late occurrence of periodic sharp-wave complexes on EEG.
Background: It is not known whether the clinical course of Japanese sporadic Creutzfeldt–Jakob disease (sCJD) cases differs from that of Caucasian sCJD cases.
Patients and methods: To investigate ...the clinical course of Japanese sCJD, clinical findings from 29 patients with Japanese MM1‐type sCJD were retrospectively evaluated and compared to Caucasian sCJD findings.
Results: Survival of Japanese MM1‐type sCJD up to the time of akinetic mutism state is similar to that of Caucasian subjects. However, the total disease duration of Japanese patients was approximately three times longer.
Conclusions: The present observations indicate that Japanese sCJD cases generally show a longer disease duration because of the longer survival period after reaching the akinetic mutism state.
No method for the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease (sCJD) has been established except for pathologic examination.
To identify a reliable marker for the clinical ...diagnosis of MM2-type sCJD.
CSF, EEG, and neuroimaging studies were performed in eight patients with MM2-type sCJD confirmed by neuropathologic, genetic, and western blot analyses.
The eight cases were pathologically classified into the cortical (n = 2), thalamic (n = 5), and combined (corticothalamic) (n = 1) forms. The cortical form was characterized by late-onset, slowly progressive dementia, cortical hyperintensity signals on diffusion-weighted imaging (DWI) of brain, and elevated levels of CSF 14-3-3 protein. The thalamic form showed various neurologic manifestations including dementia, ataxia, and pyramidal and extrapyramidal signs with onset at various ages and relatively long disease duration. Characteristic EEG and MRI abnormalities were almost absent. However, all four patients examined with cerebral blood flow (CBF) study using SPECT showed reduction of the CBF in the thalamus as well as the cerebral cortex. The combined form had features of both the cortical and the thalamic forms, showing cortical hyperintensity signals on DWI and hypometabolism of the thalamus on 18F2-fluoro-2-deoxy-d-glucose PET.
For the clinical diagnosis of MM2-type sporadic Creutzfeldt-Jakob disease, cortical hyperintensity signals on diffusion-weighted MRI are useful for the cortical form and thalamic hypoperfusion or hypometabolism on cerebral blood flow SPECT or 18F2-fluoro-2-deoxy-d-glucose PET for the thalamic form.
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