Autophagy is increased in prostate cancer cells overexpressing acid ceramidase and enhances resistance to C6 ceramide

Acid ceramidase (AC) overexpression has been observed in prostate cancer cell lines and primary tumors, and contributes to resistance to chemotherapy and radiation. The consequence of AC overexpression is the ability to convert ceramide, which is often produced as a proapoptotic response to stress, to sphingosine, which can then be converted to the prosurvival molecule sphingosine-1-phosphate. In addition to their ability to metabolize ceramide produced in response to stress, we show here that prostate cancer cell lines overexpressing AC also have increased lysosomal density and increased levels of autophagy. Furthermore, pretreatment with 3-methyladenine restores sensitivity of these cells to treatment with C(6) ceramide. We also observed increased expression of the lysosomal stabilizing protein KIF5B and increased sensitivity to the lysosomotropic agent LCL385. Thus, we conclude that AC overexpression increases autophagy in prostate cancer cells, and that increased autophagy enhances resistance to ceramide.

Identification of an intracellular microdomain of the P2X7 receptor that is crucial in basolateral membrane targeting in epithelial cells

We investigated membrane targeting of the P2X(7) receptor (P2X(7)R) in polarized epithelial cells using immunofluorescent confocal imaging. The wild-type receptor was targeted to the basolateral membrane, independently of adaptor protein μ1B. Deletion of the majority of the intracellular C-terminus, or the last 26 residues (P570-Y595), conferred targeting of the protein to the apical membrane. Alanine substitution in the microdomain P582-Q587 caused similar apical membrane targeting without major effect on the receptor function and surface expression. Our results show basolateral membrane targeting of the P2X(7)R in epithelial cells and that the intracellular C-terminal microdomain P582-Q587 is crucial in this process.

Transplantation of immortalized human fetal hepatocytes prevents acute liver failure in 90% hepatectomized mice

AIM

The aim of this study was to investigate whether human fetal hepatocytes are amenable to simian virus 40 large T-antigen (SV40Tag) mediated immortalization and whether the immortalized cells rescue mice with acute liver failure induced by 90% hepatectomy.

METHODS

We constructed a retroviral vector expressing a thermolabile mutant SV40Tag for transfer into primary human fetal hepatocytes. We quantitatively detected the synthetic ability for albumin and urea by the immortalized cells, which were subcutaneously inoculated into mice with severe combined immunodeficiency (SCID) to evaluate tumorigenzcity. The immortalized cells were also transplanted into the spleens of mice with acute liver failure.

RESULTS

One clone resulting after selection, referred to as HepCL, was highly differentiated, growing steadily in a chemically defined serum-free medium. HepCL cells were positive for albumin, cytokeratin 18, and cytokeratin 19 immunocytochemical staining. The average synthetic efficacies of HepCL cells for albumin and urea were comparable to that of unmodified primary human fetal hepatocytes. The population doubling time of HepCL cells in the logarithmic growth phase was approximately 17 hours. HepCL cells showed no oncogenicity in immunodeficient mice at 16 months. Mice receiving HepCL cells (G1) and primary human fetal hepatocytes (G2) showed significantly lower blood ammonia levels after 90% hepatectomy. Pairwise comparisons between the 4 groups showed that xenotransplantation of HepCL (G1) or primary fetal hepatocytes (G2) significantly improved survivals of recipient mice.

CONCLUSIONS

HepCL may be useful as a source of hepatic function for cell-based therapeutics in acute liver failure.

Intranasal brain-derived neurotrophic factor protects brain from ischemic insult via modulating local inflammation in rats

Inflammation plays a vital role in the pathogenesis of ischemic stroke. Brain-derived neurotrophic factor (BDNF) may protect brain tissues from ischemic injury. In this study, we investigated whether intranasal BDNF exerted neuroprotection against ischemic insult by modulating the local inflammation in rats with ischemic stroke. Rats were subjected to temporary occlusion of the right middle cerebral artery (120 min) and intranasal BDNF or vehicle was adminstrated 2 h after reperfusion. Infarct volume and neuron injury were measured using triphenyltetrazolium chloride, Nissl staining and TUNEL assay, respectively. Microglia were detected by immunohistofluorescence. Tumor necrosis factor-α, interleukin10 and mRNAs were evaluated by enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. DNA-binding activity of nuclear factor-kappa B was measured by electrophoretic mobility shift assay. BDNF level in brain tissues was markedly raised following intranasal administration. There were more Nissl positive and less TUNEL positive neurons in BDNF group than in control group while intranasal BDNF did not reduce the infarct volume significantly (n=6, 0.27±0.04 vs. 0.24±0.05, P>0.05). BDNF increased the number of activated microglia (OX-42 positive) and phagocytotic microglia (ED1 positive). BDNF suppressed tumor necrosis factor-α and mRNA expression while increasing the interleukin10 and mRNA expression. BDNF also increased DNA-binding activity of nuclear factor-kappa B (n=6, 49.78±1.23 vs. 52.89±1.64, P<0.05). Our data suggest intranasal BDNF might protect the brain against ischemic insult by modulating local inflammation via regulation of the levels of cellular, cytokine and transcription factor in the experimental stroke.

Identification of the bacterial biodiversity in koumiss by denaturing gradient gel electrophoresis and species-specific polymerase chain reaction

Bacterial biodiversity in traditional koumiss fermented milk was studied by denaturing gradient gel electrophoresis (DGGE). Target DNA bands were identified according to the reference species ladder, constructed in this study. Comigrating bands present in the DGGE profiles were resolved by species-specific PCR. The results revealed a novel bacterial profile and extensive bacterial biodiversity in koumiss. The dominant lactic acid bacteria included Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus fermentum, and Lactobacillus kefiranofaciens. Frequently encountered bacterial species were Enterococcus faecalis, Lactococcus lactis, Lactobacillus paracasei, Lactobacillus kitasatonis, and Lactobacillus kefiri. Leuconostoc mesenteroides, Streptococcus thermophilus, Lactobacillus buchneri, and Lactobacillus jensenii were occasionally found in this product. In addition, L. buchneri, L. jensenii, and L. kitasatonis, which were never previously isolated by culture-dependent methods, were identified for the first time in the Xinjiang koumiss. Furthermore, conventional cultivation was performed by plating samples on M17, de Man-Rogosa-Sharpe, Halligan-Pearce, and Kenner fecal media. The results revealed that lactobacilli were the dominant species in the koumiss ecosystem, which was consistent with the results obtained by the DGGE analysis. This is the first systematic study of the microbial composition in koumiss, and our findings will be helpful in selecting appropriate strains for the manufacture of this product at the industrial level.

Quantification of tear proteins and sPLA2-IIa alteration in patients with allergic conjunctivitis

PURPOSE

Allergic conjunctivitis (AC) has been reported to induce the instability of the tear film. The tear protein and the lipid layer play important roles in maintaining the tear film. The aim of this study was to quantify the alteration of the major tear protein components and a lipid related protein secretory type IIa phospholipase A2 (sPLA2-IIa) in tears of seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC) patients.

METHODS

Twenty-one SAC and PAC patients and thirteen normal controls completed a symptom questionnaire and underwent regular ocular examination. SAC and PAC patients were diagnosed based on the clinical presentation and elevated serum IgE levels. Schirmer test paper was used to collect tear samples from SAC and PAC patients and normal controls. Soybean trypsin inhibitor (SBTI) was used as an internal standard to analyze tear samples in 15% SDS-PAGE gel. Total tear protein and its major components from the SAC and PAC patients and normal controls were quantified by band densitometry. The major tear protein bands were determined by MALDI-TOF/TOF spectrum analysis. Western blot was used to detect the content of sPLA2-IIa in tears of allergic conjunctivitis patients and normal controls.

RESULTS

Schirmer test scores were more than 10 mm in all the SAC and PAC patients and control subjects. The tear film breakup time of SAC and PAC patients was much shorter than that of the normal controls. We obtained 15 bands of tear protein by one dimensional SDS-PAGE, in which 14 bands were determined by mass-spectrum analysis. The band densitometry analysis revealed that the total tear protein concentration was much higher in SAC and PAC patients than in normal controls (p<0.05). The quantity of tear protein band 4 (serum albumin precursor), band 6 (Ig gamma-2), band 9 (leukocyte elastase inhibitor) were also significantly higher in AC patients (p<0.05). Content of sPLA2-IIa, as shown by western blot, was much higher in AC patients than in controls.

CONCLUSIONS

The total tear protein concentration and some of the major tear protein components was increased in tears of SAC and PAC patients. In addition, the content of sPLA2-IIa in tears of SAC and PAC patients was elevated. The tear protein changes in SAC and PAC patients may contribute to instability of tear film.

Discovery of SNP in exon 14 of the <i>ADD1</i> gene and its association with fatness traits in four meat-type duck populations (Brief Report)

Abstract. Fatness traits are important economically traits in meat producing animals including duck (WU et al. 2008a, b). In human, the α-Adducin (ADD1) gene polymorphism was associated with blood pressure and other subsequent negative effects related to obesity, cardiovascular and renal failure. In fact, there was some relationship between obesity and hypertension. Thus the ADD1 gene is a candidate gene for fatness traits and the study aims to invest the relationship between the polymorphism of the ADD1 gene and fatness and growth traits.

Coherent magnetization precession in ferromagnetic (Ga,Mn)As induced by picosecond acoustic pulses

We show that the magnetization of a thin ferromagnetic (Ga,Mn)As layer can be modulated by picosecond acoustic pulses. In this approach a picosecond strain pulse injected into the structure induces a tilt of the magnetization vector M, followed by the precession of M around its equilibrium orientation. This effect can be understood in terms of changes in magnetocrystalline anisotropy induced by the pulse. A model where only one anisotropy constant is affected by the strain pulse provides a good description of the observed time-dependent response.