An immunohistochemical study of cases of sporadic and inherited frontotemporal lobar degeneration using 3R- and 4R-specific tau monoclonal antibodies

The pathological distinctions between the various clinical and pathological manifestations of frontotemporal lobar degeneration (FTLD) remain unclear. Using monoclonal antibodies specific for 3- and 4-repeat isoforms of the microtubule associated protein, tau (3R- and 4R-tau), we have performed an immunohistochemical study of the tau pathology present in 14 cases of sporadic forms of FTLD, 12 cases with Pick bodies and two cases without and in 27 cases of familial FTLD associated with 12 different mutations in the tau gene (MAPT), five cases with Pick bodies and 22 cases without. In all 12 cases of sporadic FTLD where Pick bodies were present, these contained only 3R-tau isoforms. Clinically, ten of these cases had frontotemporal dementia and two had progressive apraxia. Only 3R-tau isoforms were present in Pick bodies in those patients with familial FTLD associated with L266V, Q336R, E342V, K369I or G389R MAPT mutations. Patients with familial FTLD associated with exon 10 N279K, N296H or +16 splice site mutations showed tau pathology characterised by neuronal neurofibrillary tangles (NFT) and glial cell tangles that contained only 4R-tau isoforms, as did the NFT in P301L MAPT mutation. With the R406W mutation, NFT contained both 3R- and 4R-tau isoforms. We also observed two patients with sporadic FTLD, but without Pick bodies, in whom the tau pathology comprised only of 4R-tau isoforms. We have therefore shown by immunohistochemistry that different specific tau isoform compositions underlie the various kinds of tau pathology present in sporadic and familial FTLD. The use of such tau isoform specific antibodies may refine pathological criteria underpinning FTLD.     

In vivo transduction of murine cerebellar Purkinje cells by HIV-derived lentiviral vectors

Cerebellar Purkinje cells are key elements in motor learning and motor coordination, and therefore, it is important to clarify the mechanisms by which Purkinje cells integrate information and control cerebellar function. Gene transfer into neurons, followed by the assessment of the effects on neural function, is an effective approach for examining gene function. However, this method has not been used fully in the study of the cerebellum because adenovirus vectors, the vectors most commonly used for in vivo gene transfer, have very low affinity for Purkinje cells. In this study, we used a human immunodeficiency virus (HIV)-derived lentiviral vector and examined the transduction profile of the vector in the cerebellum. A lentiviral vector carrying the GFP gene was injected into the cerebellar cortex. Seven days after the injection, Purkinje cells were efficiently transduced without significant influence on the cell viability and synaptic functions. GFP was also expressed, though less efficiently, in other cortical interneurons and Bergmann glias. In contrast to reported findings with other viral vectors, no transduced cells were observed outside of the cerebellar cortex. Thus, when HIV-derived lentiviral vectors were injected into the cerebellar cortex, transduction was limited to the cells in the cerebellar cortex, with the highest tropism for Purkinje cells. These results suggest that HIV-derived lentiviral vectors are useful for the study of gene function in Purkinje cells as well as for application as a gene therapy tool for the treatment of diseases that affect Purkinje cells.     

Low-barrier hydrogen bond in photoactive yellow protein

Low-barrier hydrogen bonds (LBHBs) have been proposed to play roles in protein functions, including enzymatic catalysis and proton transfer. Transient formation of LBHBs is expected to stabilize specific reaction intermediates. However, based on experimental results and theoretical considerations, arguments against the importance of LBHB in proteins have been raised. The discrepancy is caused by the absence of direct identification of the hydrogen atom position. Here, we show by high-resolution neutron crystallography of photoactive yellow protein (PYP) that a LBHB exists in a protein, even in the ground state. We identified ≈87% (819/942) of the hydrogen positions in PYP and demonstrated that the hydrogen bond between the chromophore and E46 is a LBHB. This LBHB stabilizes an isolated electric charge buried in the hydrophobic environment of the protein interior. We propose that in the excited state the fast relaxation of the LBHB into a normal hydrogen bond is the trigger for photo-signal propagation to the protein moiety. These results give insights into the novel roles of LBHBs and the mechanism of the formation of LBHBs.     

Flexion-induced cervical myelopathy associated with fewer elastic fibers and thickening in the posterior dura mater

Two patients with a condition clinically resembling juvenile muscular atrophy of distal upper extremity (Hirayama disease) showed forward protrusive movement of the posterior cervical dura matter during neck flexion. The dura displacement was characteristically limited in an approximately central portion of the posterior dura, which is different from Hirayama disease, which exhibits whole posterior dura displacement. Interestingly, the restricted dura in these patients showed thickening with reduced elastic fibers, indicating that the decreased stretchability of the posterior dura had caused motor dominant cervical myelopathy.     

Casein kinase 2-interacting protein-1, a novel Akt pleckstrin homology domain-interacting protein, down-regulates PI3K/Akt signaling and suppresses tumor growth in vivo

The serine/threonine kinase Akt plays a central role in cell survival and proliferation. Its activation is linked to tumorigenesis in several human cancers. Although many Akt substrates have been elucidated, the Akt-binding proteins that regulate Akt function remain unclear. We report herein having identified casein kinase 2-interacting protein-1 (CKIP-1) as an Akt pleckstrin homology (PH) domain-binding protein with Akt inhibitory function. CKIP-1 formed a complex with each Akt isoform (Akt1, Akt2, and Akt3) via its NH2 terminus. Dimerization of CKIP-1 via its leucine zipper (LZ) motif at the COOH terminus was found to be associated with Akt inactivation because deletion of the LZ motif eliminated Akt inhibitory function, although it could still bind to Akt. Expression of the NH2 terminus-deleted CKIP-1 mutant containing the LZ motif, but lacking Akt-binding ability, induced Akt phosphorylation and activation by sequestering the ability of endogenous CKIP-1 to bind to Akt. Stable CKIP-1 expression caused Akt inactivation and cell growth inhibition in vitro. In addition, the growth of stable CKIP-1 transfectants xenografted into nude mice was slower than that of mock transfectants. These results indicate that CKIP-1, a novel Akt PH domain-interacting protein, would be a candidate of tumor suppressor with an Akt inhibitory function.     

New therapy in inflammatory bowel disease (infliximab)

In inflammatory bowel disease, such as Crohn's disease, certain immunological abnormalities are considered as its cause, but the fundamental mechanism remains unclear. However, recent researches revealed that inflammatory cytokines and adhesion molecules, such as TNFalpha, IL-6, IL-12 and alpha4 integrin, play an important role in the pathogenesis of Crohn's disease. This led to the development of anti-cytokine therapy and anti-adhesion molecules therapy using monoclonal antibodies to theses cytokines and adhesion molecules. Among them, infliximab, a chimeric monoclonal antibody to TNFalpha, is most clinically applied and marked therapeutic effect is seen in Crohn's disease. Moreover various anti-cytokine therapy was introduced in clinical fields.     

GABAA/Benzodiazepine receptor binding in patients with schizophrenia using [11C]Ro15-4513, a radioligand with relatively high affinity for alpha5 subunit

Dysfunction of the GABA system is considered to play a role in the pathology of schizophrenia. Individual subunits of GABA(A)/Benzodiazepine (BZ) receptor complex have been revealed to have different functional properties. alpha5 subunit was reported to be related to learning and memory. Changes of alpha5 subunit in schizophrenia were reported in postmortem studies, but the results were inconsistent. In this study, we examined GABA(A)/BZ receptor using [(11)C]Ro15-4513, which has relatively high affinity for alpha5 subunit, and its relation to clinical symptoms in patients with schizophrenia. [(11)C]Ro15-4513 bindings of 11 patients with schizophrenia (6 drug-na?ve and 5 drug-free) were compared with those of 12 age-matched healthy control subjects using positron emission tomography. Symptoms were assessed using the Positive and Negative Syndrome Scale. [(11)C]Ro15-4513 binding was quantified by binding potential (BP) obtained by the reference tissue model. [(11)C]Ro15-4513 binding in the prefrontal cortex and hippocampus was negatively correlated with negative symptom scores in patients with schizophrenia, although there was no significant difference in BP between patients and controls. GABA(A)/BZ receptor including alpha5 subunit in the prefrontal cortex and hippocampus might be involved in the pathophysiology of negative symptoms of schizophrenia.     

Neuroprotective effects of an extract from the inflamed skin of rabbits inoculated with vaccinia virus on glutamate-induced neurotoxicity in cultured neuronal cell line

OBJECTIVE: Protein-free extracts from the inflamed skin of rabbits inoculated with vaccinia virus (Rosemorgen and Neurotropin are widely employed to combat chronic pain and treat allergic conditions in human subjects in Japan. However, the pharmacologic mechanisms of Rosemorgen and Neurotropin remain unclear. METHODS: In this study, we examined the effects of Rosemorgen on L-glutamic acid (Glu)-induced cell death in N18-RE-105 neural cell line, which only possessed non-N-methyl-D-aspartate (NMDA)-type receptors. RESULTS: There were many large cytoplasmic cells and elongation of fivers in phosphate-buffered saline (PBS) additional group without Glu. In PBS and Glu simultaneous additional group, the survival ratio was decrease significantly compared with PBS alone group. Moreover, there were dead cells which did not have cytoplasm and aggregated nucleus. The Glu-induced cell death of N18-RE-105 cells was inhibited by both pre-treatment (24 hours before Glu treatment) and simultaneous treatment with Rosemorgen. There were many large cytoplasmic cells and elongation of fivers in Rosemorgen group. DISCUSSION: From this finding in N18-RE-105 cells, Rosemorgen was concluded to inhibit Glu-induced cell death via non-NMDA type receptors. One of the pharmacologic mechanisms of Rosemorgen has been clear. These results suggest that Rosemorgen depresses allodynia and chronic pain through interaction with non-NMDA type receptors.