Establishment of an MT4-MMP-deficient mouse strain representing an efficient tracking system for MT4-MMP/MMP-17 expression in vivo using beta-galactosidase

The biological functions of membrane-type 4 matrix metalloproteinase (MT4-MMP/MMP-17) are poorly understood because of the lack of a sensitive system for tracking its expression in vivo. We established a mutant mouse strain (Mt4-mmp(-/-)) in which Mt4-mmp was replaced with a reporter gene encoding beta-galactosidase (LacZ). Mt4-mmp(-/-) mice had normal gestations, and no apparent defects in growth, life span and fertility. Using LacZ as a marker, we were able to monitor the expression and promoter activity of Mt4-mmp for the first time in vivo. The tissue distribution of Mt4-mmp mRNA correlated with LacZ expression, and we showed that Mt4-mmp is expressed primarily in cerebrum, lung, spleen, intestine and uterus. We identified LacZ-positive neurons in the cerebrum, smooth muscle cells in the intestine and uterus, and macrophages located in the lung alveolar or intraperitoneal space. Contrary to the reported role of MT4-MMP as a tumor necrosis factor-alpha (TNF-alpha) sheddase, the lipopolysaccharide (LPS)-induced release of TNF-alpha from Mt4-mmp(-/-)macrophages was similar to that in wild-type cells, and expression of Mt4-mmp mRNA was repressed following LPS stimulation. Thus, we have established a mutant mouse strain for analyzing the physiological functions of MT4-MMP, which also serves as a sensitive system for monitoring and tracking the expression of MT4-MMP in vivo.     

Purification of a calmodulin-binding protein from chicken gizzard that interacts with F-actin.

A calmodulin-binding protein called "caldesmon" was purified from chicken gizzard muscle as the major calmodulin-binding protein in this tissue. Its molecular weight estimated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis was 150,000, and two of these polypeptides constituted the native molecule. Caldesmon is an actin-binding protein also, binding F-actin reversibly in the presence or absence of Ca2+. The interaction of caldesmon with F-actin was abolished by the binding of calmodulin with the caldesmon. Because the interaction between caldesmon and calmodulin was Ca2+-dependent but the interaction between caldesmon and F-actin was not, Ca2+ acts as a flip-flop switch between the formations of two complexes, caldesmon.calmodulin and caldesmon.F-actin: increasing the formation of the former complex at increased Ca2+ level and the formation of the latter complex at decreased Ca2+ level. The equilibrium of the formations of both complexes was achieved at a Ca2+ concentration near 1 microM.     

Circulating soluble Fas levels in patients with hepatitis C virus infection and interferon therapy

Background The clinical relevance of the circulating soluble form of the Fas-Receptor (sFas) was investigated in patients with hepatitis C receiving type 1 interferon (IFN) therapy.Methods sFas was quantified by enzyme-linked immunosorbent assay in 66 hepatitis C virus (HCV) carriers and 30 HCV-naive or previously infected controls. The levels were then monitored during enhanced treatment with type 1 IFNs in 15 chronic hepatitis C patients.Results The HCV carriers had high levels of sFas compared with controls (3.8 ± 1.3 vs 2.7 ± 0.8ng/ml; P < 0.001). sFas levels in patients with chronic HCV infection were directly related to serum alanine aminotransferase levels (r = 0.440; P < 0.001) and the histological grade (r = 0.403; P = 0.019). Among necroinflammatory reactions, only piecemeal necrosis showed a correlation with sFas levels (r = 0.556; P = 0.001). Pretreatment sFas levels, however, were not predictive of therapeutic outcomes. A sustained virological response to enhanced IFN therapy showed a relation to only the pretreatment HCV load. Interestingly, circulating sFas was upregulated when IFN- was administered at short intervals (3MU/every 12h). This upregulation was accompanied by parallel aminotransferase elevation, which was observed regardless of a virological response.Conclusions sFas elevation, in parallel with the severity of liver injury, suggests the possible upregulation of hepatic Fas expression and the Fas-mediated pathway in both HCV- and type 1 IFN-induced liver injury. The essential function of sFas to protect hepatocytes against Fas-mediated liver injury was not evident in these clinical settings.     

Dengue Hemorrhagic Fever in a Japanese Traveler with Pre-existing Japanese Encephalitis Virus Antibody

An adult Japanese man who had just returned from Thailand developed dengue hemorrhagic fever (DHF). A primary infection of dengue virus (DENV) was confirmed, specifically DENV serotype 2 (DENV-2), on the basis of the detection of the virus genome, a significant increase in the neutralizing antibody and the isolation of DENV-2. DHF is often observed following a secondary infection from another serotype of dengue virus, particularly in children, but this case was a primary infection of DENV. Japan is a non-endemic country for dengue disease. In fact, only Japanese encephalitis (JE) is known to be a member of the endemic flavivirus family. In this study, IgG antibody against Japanese encephalitis virus (JEV) was detected. JEV belongs to the family of dengue virus and prevails in Japan, particularly Kyushu. Among many risk factors for the occurrence of DHF, a plausible candidate could be a cross-reactive antibody-dependent enhancement (ADE) mechanism caused by JEV antibody. This indicates that most Japanese travelers who living in dengue non-endemic areas, particularly Kyushu, should be aware of the occurrence of DHF.     

Comparing α7 nicotinic acetylcholine receptor binding,amyloid‐β deposition,and mitochondria complex‐I function in living brain: A PET study in aged monkeys

This study was aimed to assess the correlations among α7 nicotinic acetylcholine receptor (α7‐nAChR) binding, amyloid‐β (Aβ) deposition, and mitochondrial complex I (MC‐I) activity in the brain of aged monkeys (Macaca mulatta). Positron emission tomography (PET) measurements with [¹¹C](R)‐MeQAA, [¹¹C]PIB, and [¹⁸F]BCPP‐EF were conducted in monkeys in a conscious condition. [¹¹C](R)‐MeQAA binding was analyzed by a simplified reference tissue model to calculate nondisplaceable binding potential (BP_ND), [¹¹C]PIB uptake was calculated by standard uptake value ratio (SUVR), and [¹⁸F]BCPP‐EF binding was determined by Logan graphical analysis to calculate total distribution volume (V_T) with arterial blood sampling. Higher brain uptake was determined in the thalamus, hippocampus, striatum, and cortical regions for [¹¹C](R)‐MeQAA, while being lower in the cerebellum. Significant age‐related reduction of [¹¹C](R)‐MeQAA binding to α7‐nAChR was determined only in the occipital cortex. The plot of Vt of [¹⁸F]BCPP‐EF against BP_ND of [¹¹C](R)‐MeQAA indicated a significant negative correlation in the hippocampus and cortical regions in aged animals. Plotting of SUVR of [¹¹C]PIB against BP_ND of [¹¹C](R)‐MeQAA showed a positive correlation. The in vivo binding of [¹¹C](R)‐MeQAA could reflect the upregulation of α7‐nAChR induced by neurodegenerative damage determined by Aβ deposition as well as impaired MC‐I activity in living brain. Synapse 69:475–483, 2015. © 2015 Wiley Periodicals, Inc.     

Second-order motion is less efficient at modulating vection strength

Visually induced illusions of self-motion (vection) are often induced using constant velocity optic flow. However, adding simulated viewpoint jitter and oscillation to these displayscan significantly improve the vection experience (especially when this jitter/oscillation is orthogonal to the constant flow component - Nakamura, 2010; Palmisano et al., 2008). In the present experiment, we found that vection was only facilitated when luminance-, but not contrast-, defined vertical oscillatory motion was added to the constant horizontal display motion (even though observers clearly reported seeing both the oscillatory and constant display motions in both conditions). These findings demonstrate that the vection enhancement provided by simulated viewpoint oscillation is not simply based on the perceived display motion.