Muc4 is required for activation of ErbB2 in signet ring carcinoma cell lines

Signet-ring cell carcinoma is one of the most malignant tumors, classified histologically as a poorly differentiated adenocarcinoma. The ErbB2/ErbB3 complex is often constitutively activated, which suggests that the ErbB2/ErbB3 signaling pathway may be important for malignancy of this tumor. However, the mechanism underlying this activation has not been understood. Here, we show that ErbB2 and Muc4 bind in signet ring carcinoma cells, which was not seen in highly differentiated adenocarcinoma cell lines. ErbB3 was suggested to be a substrate of ErbB2 because knockdown of ErbB2 resulted in less phosphorylation of ErbB3. Inhibition of expression of Muc4 at the cell surface by the treatment of the cells with benzyl-GalNac, an inhibitor of mucin secretion, blocked phosphorylation of ErbB3, suggesting that activity of ErbB2 depends on the expression of Muc4. These results supply the biochemical backgrounds in recent studies suggesting the contribution of Muc4 in the tumorigenesis.     

Prognostic Implication of Physical Signs of Congestion in Acute Heart Failure Patients and Its Association with Steady-State Biomarker Levels

Background

Congestive physical findings such as pulmonary rales and third heart sound (S3) are hallmarks of acute heart failure (AHF). However, their role in outcome prediction remains unclear. We sought to investigate the association between congestive physical findings upon admission, steady-state biomarkers at the time of discharge, and long-term outcomes in AHF patients.

Methods

We analyzed the data of 133 consecutive AHF patients with an established diagnosis of ischemic or non-ischemic (dilated or hypertrophic) cardiomyopathy, admitted to a single-center university hospital between 2006 and 2010. The treating physician prospectively recorded major symptoms and congestive physical findings of AHF: paroxysmal nocturnal dyspnea, orthopnea, pulmonary rales, jugular venous distension (JVD), S3, and edema. The primary endpoint was defined as rehospitalization for HF.

Results

Majority (63.9%) of the patients had non-ischemic etiology and, at the time of admission, S3 was seen in 69.9% of the patients, JVD in 54.1%, and pulmonary rales in 43.6%. The mean follow-up period was 726 ± 31days. Patients with pulmonary rales (p < 0.001) and S3 (p  =  0.011) had worse readmission rates than those without these findings; the presence of these findings was also associated with elevated troponin T (TnT) levels at the time of discharge (odds ratio [OR] 2.8; p  =  0.02 and OR 2.6; p  =  0.05, respectively).

Conclusion

Pulmonary rales and S3 were associated with inferior readmission rates and elevated TnT levels on discharge. The worsening of the readmission rate owing to congestive physical findings may be a consequence of on-going myocardial injury.     

D,L-Threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (DL-PDMP) increases endoplasmic reticulum stress, autophagy and apoptosis accompanying ceramide accumulation via ceramide synthase 5 protein expression in A549 cells

In A549 cells, the addition of D,L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (DL-PDMP) led to marked autophagy with massive microtubule-associated protein 1 light chain 3B (LC3B)-II protein expression as an indication of autophagy and a steep decrease of p62 protein as a co-indication of autophagy. The addition of DL-PDMP caused massive autophagy with an increase of CAAT/enhancer binding protein homologous protein (CHOP) expression as the marker of endoplasmic reticulum (ER) stress, lactate dehydrogenase (LDH) release without caspase 3 activation and many autophagic vacuoles/devoid of a cell membrane on morphology. On the other hand, the addition of DL-PDMP caused an increase in cellular or subcellular ceramides (Cers), especially palmitoyl-Cer, based on de novo synthesis of Cer, and led to caspase-independent apoptosis. Marked increases of Cer levels in the nuclear envelope were observed 17 h after the addition. The elevations of Cer synthase activity and longevity-assurance homologue (LASS)5 protein expression were observed in subcellular fractions from 30 min until 2 h after the addition. However, the elevations of Cer synthase activity were independent of reactive oxygen species generation or cytochrome P450 4F2 activity. Since an increase in LASS5 protein expression in subcellular fraction occur in preference to the variation of LC3B-II protein expression via CHOP expression after the addition and Cer accumulation induced by the addition contributes to ER stress, it is thought that an elevation of Cer synthase activity via LASS5 protein expression associate to autophagy via CHOP expression (ER stress) with the addition.     

Intermittent-hypoxia induced autophagy attenuates contractile dysfunction and myocardial injury in rat heart

Sleep apnea syndrome (SAS) is considered to be associated with heart failure (HF). It is known that autophagy is induced in various heart diseases thereby promotes survival, but its excess may be maladaptive. Intermittent hypoxia (IH) plays pivotal role in the pathogenesis of SAS. We aimed to clarify the relationships among IH, autophagy, and HF. Rats underwent IH at a rate of 20 cycles/h (nadir of 4% O2 to peak of 21% O2 with 0% CO2) or normal air breathing (control) for 8 h/d for 3 weeks. IH increased the cardiac LC3II/LC3I ratio. The IH induced upregulation of LC3II was attenuated by the administration of an inhibitor of autophagosome formation 3-methyladenine (3-MA), but enhanced by an inhibitor of autophagosome–lysosome fusion chloroquine (CQ), showing enhanced autophagic flux in IH hearts. Electron microscopy confirmed an increase in autophagosomes and lysosomes in IH. With 3-MA or CQ, IH induced progressive deterioration of fractional shortening (FS) on echocardiography over 3 weeks, although IH, 3-MA, or CQ alone had no effects. With CQ, IH for 4 weeks increased serum troponin T levels, reflecting necrosis. Western blotting analyses showed dephosphorylation of Akt and mammalian target of rapamycin (mTOR) at Akt (Ser2448, 2481) sites, suggesting the activation of autophagy via Akt inactivation. Conclusions. IH-mediated autophagy maintains contractile function, whereas when autophagy is inhibited, IH induces systolic dysfunction due to myocyte necrosis. General significance. This study highlighted the potential implications of autophagy in cardio-protection in early SAS patients without comorbidity, reproduced in normal rats by 3 ~ 4 weeks of IH.     

Hydrophobic core of molten-globule state of bovine carbonic anhydrase B

The interaction which stabilizes the intermediate state of the protein folding and/or unfolding is important for understanding the structure formation mechanism of proteins. The partitioning of a hydrophobic fluorescence probe, pyrene, into the core of a ‘molten globule’ structure of bovine carbonic anhydrase B was measured, revealing a partition coefficient of about 10⁴. The result leads to the conclusion that the compact structure of the molten-globule state is formed by the hydrophobic interaction, as detergent micelles are formed by the same interaction.     

SWAP-70 is important for invasive phenotypes of mouse embryo fibroblasts transformed by v-Src

SWAP-70 is a protein involved in actin rearrangement, especially in membrane ruffling. Mouse embryo fibroblasts (MEFs) deficient in SWAP-70 show impaired membrane ruffling and fail to grow in soft agar after transformation by v-Src. Here, we show that v-Src transformed MEFs expressing SWAP-70 are highly invasive. MEFs expressing SWAP-70 or v-Src alone were far less invasive, suggesting that both proteins were required for the cells to be invasive. Expression of both SWAP-70 and v-Src induced constant membrane ruffling, which may cause vigorous cell movement, probably required for invasiveness of the cells. Expression of v-Src alone morphologically transformed MEFs but formed lamellipodia rather than membrane ruffles, suggesting less aggressive nature of the cells compared with those expressing both SWAP-70 and v-Src. These results suggest that v-Src and SWAP-70 act synergistically in the invasion activity of MEFs.     

A suitable embankment mowing strategy for habitat conservation of the harvest mouse

The harvest mouse Micromys minutus (Pallas 1771), a small rodent, builds its nests on tall grasses such as Amur silvergrass Miscanthus sacchariflorus (Maxim.) Benth. This mouse species is endangered by grassland habitat loss worldwide. Although embankments are one of the mouse’s nest sites in Japan, these habitats are not stable because of regular mowing. To investigate ways of increasing the habitat suitability of embankments, research was carried out over a 2-year period in western Japan on an embankment where Amur silvergrass was dominant. Two to three divisions of the embankment were mowed at intervals in spring and autumn, and seasonal changes in nesting and vegetation were examined. Nest sites were evaluated using Manly’s index. In each year, the nesting period was extended and more nests were built compared to past years when phased mowing was not performed. The density of nests in each division increased in order of mowing in spring, but was low in autumn. Amur silvergrass was the preferred nesting plant and other perennial grasses were avoided. Annual grasses were preferred over Amur silvergrass in 2005. Nesting restarted when Amur silvergrass recovered to heights of >100 cm in all divisions, regardless of the mowing month. Each year, 120–160-cm-tall Amur silvergrass was preferred, while plants <80 cm high were avoided. Phased mowing, which allows annual grasses and Amur silvergrass sufficient time to recover, is clearly an effective method of maintaining stable nesting habitat for the harvest mouse on an embankment.