Active Transition of Fear Memory Phase from Reconsolidation to Extinction through ERK-Mediated Prevention of Reconsolidation

The retrieval of fear memory induces two opposite memory process, i.e., reconsolidation and extinction. Brief retrieval induces reconsolidation to maintain or enhance fear memory, while prolonged retrieval extinguishes this memory. Although the mechanisms of reconsolidation and extinction have been investigated, it remains unknown how fear memory phases are switched from reconsolidation to extinction during memory retrieval. Here, we show that an extracellular signal-regulated kinase (ERK)-dependent memory transition process after retrieval regulates the switch of memory phases from reconsolidation to extinction by preventing induction of reconsolidation in an inhibitory avoidance (IA) task in male mice. First, the transition memory phase, which cancels the induction of reconsolidation, but is insufficient for the acquisition of extinction, was identified after reconsolidation, but before extinction phases. Second, the reconsolidation, transition, and extinction phases after memory retrieval showed distinct molecular and cellular signatures through cAMP responsive element binding protein (CREB) and ERK phosphorylation in the amygdala, hippocampus, and medial prefrontal cortex (mPFC). The reconsolidation phase showed increased CREB phosphorylation, while the extinction phase displayed several neural populations with various combinations of CREB and/or ERK phosphorylation, in these brain regions. Interestingly, the three memory phases, including the transition phase, showed transient ERK activation immediately after retrieval. Most importantly, the blockade of ERK in the amygdala, hippocampus, or mPFC at the transition memory phase disinhibited reconsolidation-induced enhancement of IA memory. These observations suggest that the ERK-signaling pathway actively regulates the transition of memory phase from reconsolidation to extinction and this process functions as a switch that cancels reconsolidation of fear memory.SIGNIFICANCE STATEMENT Retrieval of fear memory induces two opposite memory process; reconsolidation and extinction. Reconsolidation maintains/enhances fear memory, while extinction weakens fear memory. It remains unknown how memory phases are switched from reconsolidation to extinction during retrieval. Here, we identified an active memory transition process functioning as a switch that inhibits reconsolidation. This memory transition phase showed a transient increase of extracellular signal-regulated kinase (ERK) phosphorylation in the amygdala, hippocampus and medial prefrontal cortex (mPFC). Interestingly, inhibition of ERK in these regions at the transition phase disinhibited the reconsolidation-mediated enhancement of inhibitory avoidance (IA) memory. These findings suggest that the transition memory process actively regulates the switch of fear memory phases of fear memory by preventing induction of reconsolidation through the activation of the ERK-signaling pathway.     

Magnetic Resonance Imaging Findings in Japanese Encephalitis

Ten patients with Japanese encephalitis diagnosed by serological criteria underwent magnetic resonance imaging (MRI) in axial and coronal sections. In 6, a second MRI study was done. The MRI findings were compared with the clinical outcome. Four patients died within several months of onset, 2 had sequelae such as hemiparesis and dementia, and the remaining 4 had no sequelae. In 9 of 10 patients, either diffuse or patchy white matter lesions were observed bilaterally, together with abnormalities in areas such as the thalamus, basal ganglia, and brainstem. For 3 patients who died or remained demented, the second MRI revealed extensive, diffuse white matter abnormalities. This study indicates that Japanese encephalitis can produce white matter involvement, although gray matter structures such as the thalamus, basal ganglia, and brainstem are more severely affected. The severity of these MRI lesions correlated with the clinical outcome.     

Interference with a conformational change in the haemagglutinin molecule of influenza virus by antibodies as a possible neutralization mechanism

A possible mechanism of neutralization of influenza virus by antibodies to the haemagglutinin molecule is proposed in addition to the generally accepted mechanism of blocking attachment to host cell receptors. This proposed mechanism involves interference with a low-pH-induced conformational change in the haemagglutinin molecule by bivalent binding of antibodies, which results in inhibition of the fusion step in the viral replication process.     

Superior sagittal sinus thrombosis during remission induction therapy for acute lymphoblastic leukemia

Superior sagittal sinus thrombosis (SSST) has been reported to be caused by coagulopathy following oral contraceptive therapy, DIC, infection around the sinus, compression from a tumor, infiltration of tumor, and an inherited deficiency of proteins C and S, but SSST associated with hematological malignancies and L-asparaginase (L-Asp) therapy is rare. We report a case of an adult patient with acute lymphoblastic leukemia (ALL) who developed SSST during the remission induction therapy. A 25-year-old man was admitted with left facial nerve palsy and, following bone marrow aspiration and lumbar puncture, he was diagnosed as having T-ALL with CNS involvement. He received a 1-AdVP regimen as remission induction therapy and intrathecal administration of methotrexate and cytarabine. On day 29, he had a generalized convulsion and SSST was demonstrated by imaging tests. Lymphoid malignancy (ALL in particular), the use of L-Asp, CNS involvement, and intrathecal chemotherapy might be risk factors for the occurrence SSST. When a patient with those factors develops any neurological symptoms, we should pay attention to the occurrence of SSST, as well as stroke or CNS involvement, though SSST is rare.     

Silent NK/T cell reactions to dasatinib during sustained deep molecular response before cessation are associated with longer treatment‐free remission

This study presents the final report of the multicenter, prospective tyrosine kinase inhibitor discontinuation study, D‐STOP, after a 3‐year follow‐up of 54 patients with chronic CML who discontinued dasatinib after a sustained deep molecular response (DMR) for ≥2 years with dasatinib treatment. Estimated treatment‐free remission (TFR) rates at 12 and 36 months were 63.0% [95% confidence interval (CI): 48.7‐74.3] and 59.3% (95% CI: 45.0‐71.0), respectively. CD3^?CD56⁺ NK, CD16⁺CD56⁺ NK, and CD57⁺CD56⁺ NK large granular lymphocyte (NK‐LGL), CD8⁺CD4^– cytotoxic T cell, and CD57⁺CD3⁺ T‐LGL cell numbers were relatively elevated throughout the 24‐month consolidation only in failed patients who molecularly relapsed within 12 months. In successful patients, these subsets elevated transiently after 12 months, but returned to basal levels after 24‐month consolidation. Therefore, smaller changes in NK/T, particularly the NK subset throughout consolidation, reflected higher TFR rates. TFR rates of those patients exhibiting elevation in CD3^?CD56⁺ NK >376 cells/μL, CD16⁺CD56⁺ NK > 241 cells/μL, or CD57⁺CD56⁺ NK‐LGL >242 cells/μL during consolidation compared with others were 26.7% (8.3%‐49.6%) vs 78.3% (55.4%‐90.3%), HR 0.032 (0.0027‐0.38; P = .0064), 31.2% (11.4%‐53.6%) vs 85.0% (60.4%‐94.9%), HR 0.039 (0.0031‐0.48; P = .011), or 36.8% (16.5%‐57.5%) vs 77.3% (53.7%‐89.8%), HR 0.21 (0.065‐0.69; P = .010), respectively. Therefore, silent responses of T/NK subsets to dasatinib throughout consolidation were significant for longer TFR. Elevated NK/T, particularly NK lymphocytes responsive to dasatinib, may be immunologically insufficient to maintain TFR. Their decline, subsequently replaced by altered lymphocyte population with less response to dasatinib during sustained DMR, might be immunologically significant. (D‐STOP, NCT01627132).     

Phase II study of pemetrexed plus intermittent erlotinib combination therapy for pretreated advanced non-squamous non-small cell lung cancer with documentation of epidermal growth factor receptor mutation status

Introduction

Erlotinib and pemetrexed have been approved for the second-line and maintenance treatment of non-small cell lung cancer (NSCLC). With the recommended doses determined by our previous phase I study, we conducted a phase II study to evaluate the efficacy and safety of combination of the two agents in pretreated non-squamous NSCLC patients.

Methods

This study was performed in patients with stage IIIB/IV or post-surgically recurrent non-squamous NSCLC whose disease had progressed on or after receiving first-line chemotherapy. Patients received 500 mg/m² of intravenous pemetrexed every 21 days and 150 mg of oral erlotinib on days 2–16 until disease progression, unacceptable toxicity, or withdrawal of consent. The expected response rate and threshold were defined as 33.5% and 10%, respectively. Assuming a one-sided alpha of 5%, a power of 80%, the possible deviation from assessment, 26 patients were necessary.

Results

A total of 27 patients, 16 males and 11 females were recruited. Patients had the median age of 70 years (range, 48–80 years) and included 21 stage IV diseases, 22 adenocarcinomas. Epidermal growth factor receptor (EGFR) mutations were examined in all patients. One patient had positive EGFR mutation, but the other 26 patients had wild-type EGFR. The median number of treatment courses was 3 (range, 1 to over 19). The best overall response rate and disease control rate were 11.1% and 63.0%, respectively. The median progression-free survival and overall survival were 2.8 months (95% confidence interval (CI); 1.9–7.5 months) and 15.8 months (95% CI; 9.3 months to not available), respectively. Dermal, hepatic, gastrointestinal and hematological disorders were the frequently observed adverse events. One patient experienced grade 3 drug-induced interstitial lung disease.

Conclusions

We could not demonstrate the add-on effect of intermittent erlotinib on pemetrexed in a second-line setting for patients with non-squamous NSCLC without EGFR mutations.     

p38 MAPK phosphorylation and NF-kappa B activation in human crescentic glomerulonephritis.

BACKGROUND: p38 mitogen-activated protein kinase (p38 MAPK) followed by the activation of NF-kappa B participates in the intracellular signal transduction and production of cytokines and chemokines. The pathophysiological roles of p38 MAPK and NF-kappa B in human glomerulonephritis, however, remain to be investigated. METHODS: We investigated the phosphorylated p38 MAPK (p-p38 MAPK) and activated NF-kappa B immunohistochemically in the kidneys of 34 patients with crescentic glomerulonephritis and 26 control patients with thin basement membrane disease and minimal change nephrotic syndrome. We also explored the co-localization of p-p38 MAPK with CCR5, the signal of which leads to p38 MAPK activation. Furthermore, urinary levels of MIP-1 alpha, the cognate ligand for CCR5, were determined by enzyme-linked immunosorbent assay. RESULTS: p-p38 MAPK-positive cells and activated NF-kappa B-positive cells were mainly detected in crescentic lesions, tubular epithelial cells, and interstitial mononuclear infiltrates. The number of p-p38 MAPK-positive cells in patients with crescentic glomerulonephritis was higher than that in control patients. The number of p-p38 MAPK-positive cells in glomeruli was well correlated with the percentage of cellular crescents, the number of CD68-positive cells, and urinary MIP-1 alpha levels. In addition, the number of activated NF-kappa B-positive cells was well correlated with the number of p-p38 MAPK-positive cells in glomeruli. Dual staining revealed that most of CCR5-positive cells were positive for p-p38 MAPK. Finally, p-p38 MAPK-positive cells and activated NF-kappa B-positive cells decreased during glucocorticoid therapy-induced convalescence. CONCLUSIONS: We conclude that the phosphorylation of p38 MAPK associated with the activation of NF-kappa B may be involved in the upregulation of intrarenal MIP-1 alpha and the utilization of CCR5 signalling, which may result in human crescentic glomerulonephritis.     

Synthesis and preliminary evaluation of [18F]FEtP4A,a promising PET tracer for mapping acetylcholinesterase in vivo

N-[18F]Fluoroethyl-4-piperidyl acetate ([18F]FEtP4A), an analog of [11C]MP4A for mapping brain acetylcholineseterase (AchE) activity, was prepared by reacting 4-piperidyl acetate (P4A) with [18F]fluoroethyl bromide ([18F]FEtBr) using a newly developed automated system. Preliminary evaluation showed that the initial uptake of [18F]FEtP4A in the mouse brain was > 8% injected dose/g tissue. The distribution pattern of [18F]FEtP4A in the brain was striatum>cerebral cortex>cerebellum within 10-120 min post-injection, which reflected the distribution rank pattern of AchE activity in the brain. Moreover, chemical analysis of in vivo radioactive metabolites in the mouse brain indicated that 83% of [18F]FEtP4A was hydrolyzed to N-[18F]fluoroethyl-4-piperidinol ([18F]FEtP4OH) after 1 min intravenous injection. From these results, [18F]FEtP4A may become a promising PET tracer for mapping the AchE in vivo.     

Time-varying cortical activations related to visual-tactile cross-modal links in spatial selective attention

The neural mechanisms underlying unimodal spatial attention have long been studied, but the cortical processes underlying cross-modal links remain a matter of debate. To reveal the cortical processes underlying the cross-modal links between vision and touch in spatial attention, we recorded magnetoencephalographic (MEG) responses to electrocutaneous stimuli when subjects directed attention to an electrocutaneous or visual stimulus presented randomly in the left or right space. Neural responses recorded around the bilateral sylvian fissures at 85 and 100 ms after the electrocutaneous stimulus were significantly enhanced by spatial attention in both the touch-irrelevant and -relevant modalities. Source analysis revealed that the sylvian responses were generated in the secondary somatosensory cortex (SII). An early response, M50c, generated in the contralateral primary somatosensory cortex (SI), was not modulated by attention. There were no significant attentional changes in the source location or magnetic field distribution, suggesting attentional facilitation of the neural activity in SII itself, rather than a tonic bias effect or overlapping of separate neuronal populations. The results show that spatial attention enhances responses to tactile inputs in SII, independent of sensory modality attended. The underlying mechanism remains to be determined, but may be an increase in gain.