Does conditioned taste aversion learning in the pond snail Lymnaea stagnalis produce conditioned fear?

In conditioned taste aversion (CTA) training performed on the pond snail Lymnaea stagnalis, a stimulus (the conditional stimulus, CS; e.g., sucrose) that elicits a feeding response is paired with an aversive stimulus (the unconditional stimulus, US) that elicits the whole-body withdrawal response and inhibits feeding. After CTA training and memory formation, the CS no longer elicits feeding. We hypothesize that one reason for this result is that after CTA training the CS now elicits a fear response. Consistent with this hypothesis, we predict the CS will cause (1) the heart to skip a beat and (2) a significant change in the heart rate. Such changes are seen in mammalian preparations exposed to fearful stimuli. We found that in snails exhibiting long-term memory for one-trial CTA (i.e., good learners) the CS significantly increased the probability of a skipped heartbeat, but did not significantly change the heart rate. The probability of a skipped heartbeat was unaltered in control snails given backward conditioning (US followed by CS) or in snails that did not acquire associative learning (i.e., poor learners) after the one-trial CTA training. These results suggest that as a consequence of acquiring CTA, the CS evokes conditioned fear in the conditioned snails, as evidenced by a change in the nervous system control of cardiac activity.     

High clonality of virus-specific T lymphocytes defined by TCR usage in the brains of mice infected with West Nile virus

It has been reported that brain-infiltrating T lymphocytes play critical roles in the clearance of West Nile virus (WNV) from the brains of mice. We characterized brain-infiltrating T lymphocytes by analyzing the TCR α- and β-chain repertoires, T cell clonality, and CDR3 sequences. CD3(+)CD8(+) T cells were localized in the WNV-infected brains. The expression of CD3, CD8, CD25, CD69, perforin, and granzymes positively correlated with viral RNA levels, and high levels of expression of IFN-γ, TNF-α, and IL-2 were detected in the brains, suggesting that Th1-like cytotoxic CD8(+) T cells are expanded in the brains in response to WNV infection. The brain-infiltrating T lymphocytes dominantly used TCR genes, VA1-1, VA2-1, VB5-2, and VB8-2, and exhibited a highly oligoclonal TCR repertoire. Interestingly, the brain-infiltrating T lymphocytes had different patterns of TCR repertoire usages among WNV-, Japanese encephalitis virus-, and tick-borne encephalitis virus-infected mice. Moreover, CD8(+) T cells isolated from the brains of WNV-infected mice produced IFN-γ and TNF-α after in vitro stimulation with peritoneal cells infected with WNV, but not with Japanese encephalitis virus. The results suggest that the infiltrating CD8(+) T cells were WNV-specific, but not cross-reactive among flaviviruses. T cells from the WNV-infected brains exhibited identical or similar CDR3 sequences in TCRα among tested mice, but somewhat diverse sequences in TCRβ. The results indicate that WNV-specific CD3(+)CD8(+) T cells expanding in the infected brains are highly oligoclonal, and they suggest that TCR α-chains play a dominant and critical role in Ag specificity of WNV-specific T cells.     

Characteristics of Attempted Suicide by Patients with Schizophrenia Compared with Those with Mood Disorders: A Case-Controlled Study in Northern Japan

Recent reports suggest a lifetime suicide risk for schizophrenia patients of approximately 5%. This figure is significantly higher than the general population suicide risk consequently, detection of those at risk is clinically important. This study was undertaken to define the characteristics of suicide attempts by schizophrenia patients compared with attempts by patients with mood disorders. All patients were diagnosed using the ICD-10 criteria. The study population comprised 65 patients with F2 disorders (schizophrenia, schizotypal and delusional disorders), i.e., “the F2 group”, and 94 patients with F3 disorders (mood disorders), i.e., “the F3 group”, who presented in the clinical setting of consultation-liaison psychiatry. The F2 group had a significantly younger mean age and significantly higher ratios of ‘past/present psychiatric treatment’ and ‘more than 3 months interruption of psychiatric treatment’. In contrast, the ratios of ‘physical disorder comorbidity’, ‘alcohol intake at suicide attempt’ and ‘suicide note left behind’ were significantly higher in the F3 group. The F2 group attempted suicide by significantly more serious methods. Furthermore, ‘hallucination-delusion’ was the most prevalent motive in the F2 group and was the only factor that showed a significant association with the seriousness of the method of suicide attempt (OR = 3.36, 95% CI: 1.05–11.33).     

Familial Clusters of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis

Objective

HTLV-1 proviral loads (PVLs) and some genetic factors are reported to be associated with the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). However, there are very few reports on HAM/TSP having family history. We aimed to define the clinical features and laboratory indications associated with HAM/TSP having family history.

Methods

Records of 784 HAM/TSP patients who were hospitalized in Kagoshima University Hospital and related hospitals from 1987 to 2012 were reviewed. Using an unmatched case-control design, 40 patients of HAM/TSP having family history (f-HAM/TSP) were compared with 124 patients suffering from sporadic HAM/TSP, who were admitted in series over the last 10 years for associated clinical features.

Results

Of the 784 patients, 40 (5.1%) were f-HAM/TSP cases. Compared with sporadic cases, the age of onset was earlier (41.3 vs. 51.6 years, p<0.001), motor disability grades were lower (4.0 vs. 4.9, p = 0.043) despite longer duration of illness (14.3 vs. 10.2 years, p = 0.026), time elapsed between onset and wheelchair use in daily life was longer (18.3 vs. 10.0 years, p = 0.025), cases with rapid disease progression were fewer (10.0% vs. 28.2%, p = 0.019), and protein levels in cerebrospinal fluid (CSF) were significantly lower in f-HAM/TSP cases (29.9 vs. 42.5 mg, p<0.001). There was no difference in HTLV-1 PVLs, anti-HTLV-1 antibody titers in serum and CSF, or cell number and neopterin levels in CSF. Furthermore, HTLV-1 PVLs were lower in cases with rapid disease progression than in those with slow progression in both f-HAM/TSP and sporadic cases.

Conclusions

We demonstrated that HAM/TSP aggregates in the family, with a younger age of onset and a slow rate of progression in f-HAM/TSP cases compared with sporadic cases. These data also suggested that factors other than HTLV-1 PVLs contribute to the disease course of HAM/TSP.     

Persistent Release of IL-1s from Skin Is Associated with Systemic Cardio-Vascular Disease,Emaciation and Systemic Amyloidosis: The Potential of Anti-IL-1 Therapy for Systemic Inflammatory Diseases

The skin is an immune organ that contains innate and acquired immune systems and thus is able to respond to exogenous stimuli producing large amount of proinflammatory cytokines including IL-1 and IL-1 family members. The role of the epidermal IL-1 is not limited to initiation of local inflammatory responses, but also to induction of systemic inflammation. However, association of persistent release of IL-1 family members from severe skin inflammatory diseases such as psoriasis, epidermolysis bullosa, atopic dermatitis, blistering diseases and desmoglein-1 deficiency syndrome with diseases in systemic organs have not been so far assessed. Here, we showed the occurrence of severe systemic cardiovascular diseases and metabolic abnormalities including aberrant vascular wall remodeling with aortic stenosis, cardiomegaly, impaired limb and tail circulation, fatty tissue loss and systemic amyloid deposition in multiple organs with liver and kidney dysfunction in mouse models with severe dermatitis caused by persistent release of IL-1s from the skin. These morbid conditions were ameliorated by simultaneous administration of anti-IL-1α and IL-1β antibodies. These findings may explain the morbid association of arteriosclerosis, heart involvement, amyloidosis and cachexia in severe systemic skin diseases and systemic autoinflammatory diseases, and support the value of anti-IL-1 therapy for systemic inflammatory diseases.     

4-Dimethylaminobenzylamine as a sensitive chemiluminescence derivatization reagent for 5-hydroxyindoles and its application to their quantification in human platelet-poor plasma

A selective and sensitive high-performance liquid chromatographic method with chemiluminescence detection for the determination of 5-hydroxyindoles is described, based on the reaction of 5-hydroxyindoles with 4-dimethylaminobenzylamine. Serotonin, 5-hydroxyindole-3-acetic acid, 5-hydroxytryptophol, 5-hydroxyindole-3-acetamide and N-acetyl-5-hydroxytryptamine were used as model compounds to optimize the derivatization and chemiluminescent reaction. The reagent reacts with 5-hydroxyindoles in slightly alkaline media in the presence of potassium hexacyanoferrate(III) to give the corresponding derivatives, which can be separated on a reversed-phase column, Wakosil-II 5C18RS, with aqueous acetonitrile as an eluent. The derivatives were detected by peroxyoxalate chemiluminescence detection. The detection limits are in the range of 0.5–1.2 fmol per 100-μl injection. The method was applied to the simultaneous determination of serotonin and 5-hydroxyindole-3-acetic acid in human platelet-poor plasma.     

The Arabidopsis ortholog of the DEAH-box ATPase Prp16 influences auxin-mediated development

In animals and yeasts, the DEAH-box RNA-dependent ATPase Prp16 facilitates pre-mRNA splicing. However, in Chlamydomonas reinhardtii and Caenorhabditis elegans, Prp16 orthologs are not important for general pre-mRNA splicing, but are required for gene silencing and sex determination, respectively. The CLUMSY VEIN (CUV) gene, which encodes a unique Prp16 ortholog in Arabidopsis thaliana, influences auxin-mediated development. A loss-of-function cuv-1 mutation tells us that CUV does not facilitate splicing of pre-mRNA substrates indiscriminately, but differentially effects splicing and expression of genes. Here we show that CUV influences root-meristem maintenance and planar polarity of root-hair positioning, both of which are processes regulated by auxin. We propose that Arabidopsis PRP16/CUV differentially facilitates the expression of genes, including genes involved in auxin biosynthesis, transport, perception and signaling, and that in this way it influences auxin-mediated development.     

Brain-derived Neurotrophic Factor (BDNF) Induces Sustained Intracellular Ca2+ Elevation through the Up-regulation of Surface Transient Receptor Potential 3 (TRPC3) Channels in Rodent Microglia

Microglia are immune cells that release factors, including proinflammatory cytokines, nitric oxide (NO), and neurotrophins, following activation after disturbance in the brain. Elevation of intracellular Ca²⁺ concentration ([Ca²⁺]_i) is important for microglial functions such as the release of cytokines and NO from activated microglia. There is increasing evidence suggesting that pathophysiology of neuropsychiatric disorders is related to the inflammatory responses mediated by microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia as well as in pathophysiology and/or treatment of neuropsychiatric disorders. In this study, we sought to examine the underlying mechanism of BDNF-induced sustained increase in [Ca²⁺]_i in rodent microglial cells. We observed that canonical transient receptor potential 3 (TRPC3) channels contribute to the maintenance of BDNF-induced sustained intracellular Ca²⁺ elevation. Immunocytochemical technique and flow cytometry also revealed that BDNF rapidly up-regulated the surface expression of TRPC3 channels in rodent microglial cells. In addition, pretreatment with BDNF suppressed the production of NO induced by tumor necrosis factor α (TNFα), which was prevented by co-adiministration of a selective TRPC3 inhibitor. These suggest that BDNF induces sustained intracellular Ca²⁺ elevation through the up-regulation of surface TRPC3 channels and TRPC3 channels could be important for the BDNF-induced suppression of the NO production in activated microglia. We show that TRPC3 channels could also play important roles in microglial functions, which might be important for the regulation of inflammatory responses and may also be involved in the pathophysiology and/or the treatment of neuropsychiatric disorders.     

RAG-1 and Ly6D Independently Reflect Progression in the B Lymphoid Lineage

Common lymphoid progenitors (CLPs) are thought to represent major intermediates in the transition of hematopoietic stem cells (HSCs) to B lineage lymphocytes. However, it has been obvious for some time that CLPs are heterogeneous, and there has been controversy concerning their differentiation potential. We have now resolved four Flt3⁺ CLP subsets that are relatively homogenous and capable of forming B cells. Differentiation potential and gene expression patterns suggest Flt3⁺ CLPs lacking both Ly6D and RAG-1 are the least differentiated. In addition to B cells, they generate natural killer (NK) and dendritic cells (DCs). At the other extreme is a subset of the recently described Flt3⁺ Ly6D⁺ CLPs that have a history of RAG-1 expression and are B lineage restricted. These relatively abundant and potent CLPs were depleted within 48 hours of acute in vivo estrogen elevation, suggesting they descend from hormone regulated progenitors. This contrasts with the hormone insensitivity of other CLP subsets that include NK lineage progenitors. This progenitor heterogeneity and differentiation complexity may add flexibility in response to environmental changes. Expression of RAG-1 and display of Ly6D are both milestone events, but they are neither synchronized nor dependent on each other.