A pathway of neuregulin-induced activation of cofilin-phosphatase Slingshot and cofilin in lamellipodia

Cofilin mediates lamellipodium extension and polarized cell migration by stimulating actin filament dynamics at the leading edge of migrating cells. Cofilin is inactivated by phosphorylation at Ser-3 and reactivated by cofilin-phosphatase Slingshot-1L (SSH1L). Little is known of signaling mechanisms of cofilin activation and how this activation is spatially regulated. Here, we show that cofilin-phosphatase activity of SSH1L increases ∼10-fold by association with actin filaments, which indicates that actin assembly at the leading edge per se triggers local activation of SSH1L and thereby stimulates cofilin-mediated actin turnover in lamellipodia. We also provide evidence that 14-3-3 proteins inhibit SSH1L activity, dependent on the phosphorylation of Ser-937 and Ser-978 of SSH1L. Stimulation of cells with neuregulin-1β induced Ser-978 dephosphorylation, translocation of SSH1L onto F-actin–rich lamellipodia, and cofilin dephosphorylation. These findings suggest that SSH1L is locally activated by translocation to and association with F-actin in lamellipodia in response to neuregulin-1β and 14-3-3 proteins negatively regulate SSH1L activity by sequestering it in the cytoplasm

The vascular endothelial growth factor (VEGF) receptor-2 is a major regulator of VEGF-mediated salvage effect in murine acute hepatic failure

Although administration of the vascular endothelial growth factor (VEGF), a potent angiogenic factor, could improve the overall survival of destroyed sinusoidal endothelial cells (SEC) in chemically induced murine acute hepatic failure (AHF), the mechanistic roles of the VEGF receptors have not been elucidated yet. The respective roles of VEGF receptors; namely, Flt-1 (VEGFR-1: R1) and KDR/Flk-1 (VEGFR-2: R2), in the D-galactosamine (Gal-N) and lipopolysaccharide (LPS)-induced AHF were elucidated with specific neutralizing monoclonal antibody against R1 and R2 (R1-mAb and R2-mAb, respectively). The serum ALT elevation, with a peak at 24 h after Gal-N+LPS intoxication, was markedly augmented by means of the R1-mAb and R2-mAb. The aggregative effect of R2-mAb was more potent than that of R1-mAb, and the survival rate was 70% in the R2-mAb-treated group and 100% in the other groups. The results of SEC destruction were almost parallel to those of the ALT changes. Our in-vitro study showed that R1-mAb and R2-mAb significantly worsened the Gal-N+LPS-induced cytotoxicity and apoptosis of SEC mediated by caspase-3, which were almost of similar magnitude to those in the in-vivo study. In conclusion, these results indicated that R2 is a major regulator of the salvage effect of VEGF on the maintenance of SEC architecture and the anti-apoptotic effects against chemically-induced murine AHF

Salvage living donor liver transplantation after percutaneous transluminal angioplasty for recurrent Budd-Chiari syndrome: a case report

<p>Abstract</p> <p>Introduction</p> <p>Budd-Chiari syndrome is a very rare pathological entity that ultimately leads to liver failure. Several therapeutic modalities, including percutaneous transluminal angioplasty, have been attempted to save the life of patients with Budd-Chiari syndrome. Few reports have described a salvage living donor liver transplantation performed after percutaneous transluminal angioplasty in a patient with acute Budd-Chiari syndrome.</p> <p>Case presentation</p> <p>A 26-year-old Japanese man developed severe progressive manifestations, such as massive ascites and hematemesis due to rupture of esophageal varices. After making several investigations, we diagnosed the case as Budd-Chiari syndrome. We first performed percutaneous transluminal angioplasty to dilate a short-segment stenosis of his inferior vena cava. The first percutaneous transluminal angioplasty greatly improved the clinical manifestations. However, after a year, re-stenosis was detected, and a second percutaneous transluminal angioplasty failed to open the severe stricture of his inferior vena cava. Since our patient had manifestations of acute liver failure, we decided to perform salvage living donor liver transplantation from his brother. The transplantation was successfully performed and all clinical manifestations were remarkably alleviated.</p> <p>Conclusion</p> <p>In cases of recurrent Budd-Chiari syndrome, the blocked hepatic venous outflow is not always relieved, even with invasive therapies. We have to take into account the possibility of adopting alternative salvage therapies if the first therapeutic modalities fail. When invasive therapy such as percutaneous transluminal angioplasty fails, liver transplantation should be considered as an alternative option.</p

Inter-organ Wingless/Ror/Akt signaling regulates nutrient-dependent hyperarborization of somatosensory neurons

Nutrition in early life has profound effects on an organism, altering processes such as organogenesis. However, little is known about how specific nutrients affect neuronal development. Dendrites of class IV dendritic arborization neurons in Drosophila larvae become more complex when the larvae are reared on a low-yeast diet compared to a high-yeast diet. Our systematic search for key nutrients revealed that the neurons increase their dendritic terminal densities in response to a combined deficiency in vitamins, metal ions, and cholesterol. The deficiency of these nutrients upregulates Wingless in a closely located tissue, body wall muscle. Muscle-derived Wingless activates Akt in the neurons through the receptor tyrosine kinase Ror, which promotes the dendrite branching. In larval muscles, the expression of wingless is regulated not only in this key nutrient-dependent manner, but also by the JAK/STAT signaling pathway. Additionally, the low-yeast diet blunts neuronal light responsiveness and light avoidance behavior, which may help larvae optimize their survival strategies under low-nutritional conditions. Together, our studies illustrate how the availability of specific nutrients affects neuronal development through inter-organ signaling

The N-terminal fragment of a PB2 subunit from the influenza A virus (A/Hong Kong/156/1997 H5N1) effectively inhibits RNP activity and viral replication.

Influenza A virus has a RNA-dependent RNA polymerase (RdRp) that is composed of three subunits (PB1, PB2 and PA subunit), which assemble with nucleoproteins (NP) and a viral RNA (vRNA) to form a RNP complex in the host nucleus. Recently, we demonstrated that the combination of influenza ribonucleoprotein (RNP) components is important for both its assembly and activity. Therefore, we questioned whether the inhibition of the RNP combination via an incompatible component in the RNP complex could become a methodology for an anti-influenza drug.We found that a H5N1 PB2 subunit efficiently inhibits H1N1 RNP assembly and activity. Moreover, we determined the domains and important amino acids on the N-terminus of the PB2 subunit that are required for a strong inhibitory effect. The NP binding site of the PB2 subunit is important for the inhibition of RNP activity by another strain. A plaque assay also confirmed that a fragment of the PB2 subunit could inhibit viral replication.Our results suggest that the N-terminal fragment of a PB2 subunit becomes an inhibitor that targets influenza RNP activity that is different from that targeted by current drugs such as M2 and NA inhibitors

A histologically proven case of progressive liver sarcoidosis with variceal rupture

Sarcoidosis is a chronic multi-systemic granulomatous disease, and liver involvement frequently occurs. in most cases, no evidence of liver dysfunction is observed, and portal hypertension due to sarcoid liver diseases is a rareoccurrence. Moreover, no case of liver sarcoidosis has ever been reported with confirmation of the disease progression. Herein we describe a patient having hepatic sarcoidosis with severe portal hypertension and liver dysfunction. The diagnosis was histologically confirmed from granulomatous status to established liver cirrhosis over 10 years. A 46-year-old woman developed massive hematemesis due to the rupture of gastric cardial varices. She underwent emergency endoscopic injection sclerotherapy, and clear evidence of chronic hepatic failure. Twelve years ago, she was diagnosed as having sarcoidosis with respiratory clinicalsymptoms. Liver biopsy revealed asymptomatic incidental granulomas without fibrosis development. After a couple of years, features of liver dysfunction were manifest and progressed. Ten years after the first biopsy, a second liver biopsy was performed, and well established dense fibrosis was revealed. Although significant liver dysfunction with portal hypertension is rarely seen in sarcoidosis, this case indicates that we have to consider the possibility that sarcoidosis may cause end-stage liver cirrhosis

Evaluation of performance of the GENECUBE assay for rapid molecular identification of Staphylococcus aureus and methicillin resistance in positive blood culture medium.

Rapid identification of causative agents from positive blood culture media is a prerequisite for the timely targeted treatment of patients with sepsis. The GENECUBE (TOYOBO Co., Ltd.) is a novel, fully-automated gene analyzer that can purify DNAs and amplify target DNAs. In this study, we evaluated the ability of two newly developed GENECUBE assays to directly detect the nuc and mecA genes in blood culture medium; nuc is specific to Staphylococcus aureus, and mecA indicates methicillin resistance. We examined 263 positive blood culture samples taken at three hospitals from patients suspected of having staphylococcal bacteremia. The results were then compared with those obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, antimicrobial susceptibility testing (Microscan system or Dry-plate EIKEN), and sequencing analysis. The GENECUBE assays had sensitivity and specificity of 100% in detecting both S. aureus and methicillin resistance in positive blood culture. The turnaround time of the examination was evaluated for 36 positive blood culture samples. The time between the initiation of incubation and completion of the GENECUBE examination was 23 h (interquartile range: IQR 21-37 h); the time between reporting of Gram stain examination and completion of the GENECUBE examination was 52 min (IQR 48-62 min). These findings show that the GENECUBE assays significantly reduce the assay time with no loss of sensitivity or specificity

Searching important amino acid for an inhibitory effect.

<p>(A) The compared differences of the amino acids between WSN and HK/Frag.10 are shown. (B and C) The WSN/RNP activities are expressed as a % relative to the WSN/RNP activity without the inhibitors (Control). The activities were measured via luciferase (B) and dual luciferase assay (C). The standard deviations and significant differences were calculated from three independent trials. * and ** indicate statistically significant differences at <0.05 and <0.01, respectively, in a Student’s t-test (n = 3).</p

Confirmation of the binding to other subunits.

<p>(A) The inhibitory effect of HK/Frag.10-TAP was confirmed. The RNP activities are expressed as a % relative to the WSN/RNP activity without the inhibitor. The standard deviations were calculated from three independent trials. ** indicates statistically significant differences at <0.01, using a Student’s t-test (n = 3). (B) Protein expression levels of WSN/RNP components and HK/Frag.10-TAP were confirmed by western-blotting using specific antibodies. (C) Binding to the other subunit such as WSN/PB1, WSN/PB2 and WSN/NP was confirmed by co-purification and western blotting. Crude lysates (Lanes 1 to 3) were purified via the TAP-purification method (Lanes 4 to 6). The WSN/RNP without HK/Frag.10-TAP were expressed and analyzed as a negative control (Lanes 1 and 4). As trimeric components, WSN/PB1, WSN/PA and HK/Frag.10-TAP were co-expressed (Lane 2) and purified via TAP purification (Lane 5). As RNP components, WSN/PB1, WSN/PA, WSN/NP, WSN/vNA RNA and HK/Frag.10-TAP were co-expressed (Lane 3) and purified by TAP purification (Lane 6). In lanes 4 to 6, the molecular size of HK/Frag.10 was shifted from 44 kDa to 23 kDa as a result of the cleavage by TEV protease for eluting proteins from the IgG sephalose column. The table indicates which subunits and HK/Frag.10-TAP were co-transfected in 293T cell. A reproduction of the result was confirmed by two independent trials.</p