CSK may be a potential prognostic biomarker reflecting the immune status of gastric cancer

OBJECTIVE

C-terminal Src kinase (CSK), a sarcoma (Src) homologous family kinase, is one of the most important negative regulators. It acts as a tumor suppressor by inhibiting the activity of Src family tyrosine kinases. Paradoxically, CSK is highly expressed in a variety of common tumors. Therefore, we report the expression profile of CSK in pan-cancer patients, focusing on the prognostic value, immune infiltration pattern, and biological function of CSK in gastric cancer.

MATERIALS AND METHODS

We used the TCGA database to analyze CSK expression, clinical relevance, prognostic significance, assessment of the tumor immune microenvironment, and GO and Kegg enrichment analysis based on co-expressed genes using a bioinformatics approach.

RESULTS

CSK is a protective factor in gastric cancer, and its expression correlates with the level of immune cell infiltration and immune checkpoint molecules.

CONCLUSIONS

Our findings suggest that CSK is an independent prognostic factor in gastric cancer and may predict molecular targeting and immunotherapy and provide ideas for its therapeutic strategy.

Coordinate regulation of residual bone marrow function by paracrine trafficking of AML exosomes

We recently demonstrated that acute myeloid leukemia (AML) cell lines and patient-derived blasts release exosomes that carry RNA and protein; following an in vitro transfer, AML exosomes produce proangiogenic changes in bystander cells. We reasoned that paracrine exosome trafficking may have a broader role in shaping the leukemic niche. In a series of in vitro studies and murine xenografts, we demonstrate that AML exosomes downregulate critical retention factors (Scf, Cxcl12) in stromal cells, leading to hematopoietic stem and progenitor cell (HSPC) mobilization from the bone marrow. Exosome trafficking also regulates HSPC directly, and we demonstrate declining clonogenicity, loss of CXCR4 and c-Kit expression, and the consistent repression of several hematopoietic transcription factors, including c-Myb, Cebp-β and Hoxa-9. Additional experiments using a model of extramedullary AML or direct intrafemoral injection of purified exosomes reveal that the erosion of HSPC function can occur independent of direct cell-cell contact with leukemia cells. Finally, using a novel multiplex proteomics technique, we identified candidate pathways involved in the direct exosome-mediated modulation of HSPC function. In aggregate, this work suggests that AML exosomes participate in the suppression of residual hematopoietic function that precedes widespread leukemic invasion of the bone marrow directly and indirectly via stromal components.

Identification of quantitative trait loci conferring blast resistance in Bodao, a japonica rice landrace

Bodao, a japonica landrace from the Taihu Lake region of China, is highly resistant to most Chinese isolates of Magnaporthe oryzea, a form of rice blast. To effectively dissect the influence of genetics on this blast resistance, a population of 155 recombinant inbred lines (F2:8) derived from a cross of Bodao x Suyunuo was inoculated with 12 blast isolates. Using a quantitative trait locus (QTL) mapping approach, 13 QTL on chromosomes 1, 2, 9, 11, and 12 were detected from Bodao. Five QTL, including qtl11-1-1, qtl11-3-7, qtl11-4-9, qtl12-1-1, and qtl12-2-3, have not been previously reported. The qtl11-3-7 and qtl11-4-9 may be the two main effective QTL and resistant to 7 and 9 isolates, respectively. The results of the present study will be valuable for the fine mapping and cloning of these two new resistance genes.

Single-chain recombinant HLA-DQ2.5/peptide molecules block α2-gliadin-specific pathogenic CD4+ T-cell proliferation and attenuate production of inflammatory cytokines: a potential therapy for celiac disease

Celiac disease (CD) is a disorder of the small intestine caused by intolerance to wheat gluten and related proteins in barley and rye. CD4(+) T cells have a central role in CD, recognizing and binding complexes of HLA-DQ2.5 bearing gluten peptides that have survived digestion and that are deamidated by tissue transglutaminase (TG2), propagating a cascade of inflammatory processes that damage and eventually destroy the villous tissue structures of the small intestine. In this study, we present data showing that recombinant DQ2.5-derived molecules bearing covalently tethered α2-gliadin-61-71 peptide have a remarkable ability to block antigen-specific T-cell proliferation and inhibited proinflammatory cytokine secretion in human DQ2.5-restricted α2-gliadin-specific T-cell clones obtained from patients with CD. The results from our in vitro studies suggest that HLA-DQ2.5-derived molecules could significantly inhibit and perhaps reverse the intestinal pathology caused by T-cell-mediated inflammation and the associated production of proinflammatory cytokines.

Calcium-sensing receptor and recovery from hypocalcaemia in thyroparathyroidectomized rats

BACKGROUND

Plasma ionized calcium (p-Ca(2+)) is kept within a very narrow range and deviations are rapidly corrected by flux of Ca(2+) between extracellular fluid and the labile calcium pool at the quiescent bone surface. The calcium sensing at the bone surface represents a physiological interesting model for the rapid minute-to-minute regulation of p-Ca(2+). Our aim was to study whether the calcium-sensing receptor (CaR) has a role in the rapid recovery of p-Ca(2+) from acute induced hypocalcaemia.

MATERIAL AND METHODS

Male Wistar rats were thyroparathyroidectomized (TPTX). Acute hypocalcaemia in the animals was induced by infusion of EGTA (40-50 mM EGTA, 3.0 mL h(-1) for 30 min). Thereafter the recovery of p-Ca(2+) was followed. Vehicle or the CaR activators, R-568 (2 mg as a bolus twice) or gentamycin were administrated intravenously.

RESULTS

EGTA infusion resulted in significantly lower nadir of hypocalcaemia in R-568- or gentamycin-treated rats compared to vehicle-treated rats (P < 0.01). During recovery phase p-Ca(2+) remained significantly lower in R-568 rats (P < 0.001). As such p-Ca(2+) levels recovered to basal levels in the vehicle group within 70 min after stopping EGTA, while R-568 or gentamycin rats remained significantly hypocalcaemic.

CONCLUSIONS

The CaR activators R-568 and gentamycin, both significantly delayed the recovery of p-Ca(2+) from acute EGTA-induced hypocalcaemia in TPTX rats. This novel finding suggests the existence of calcium sensing by bone of importance for the rapid minute-to-minute regulation of p-Ca(2+).

Accurate classification of protein structural families using coherent subgraph analysis

Protein structural annotation and classification is an important problem in bioinformatics. We report on the development of an efficient subgraph mining technique and its application to finding characteristic substructural patterns within protein structural families. In our method, protein structures are represented by graphs where the nodes are residues and the edges connect residues found within certain distance from each other. Application of subgraph mining to proteins is challenging for a number reasons: (1) protein graphs are large and complex, (2) current protein databases are large and continue to grow rapidly, and (3) only a small fraction of the frequent subgraphs among the huge pool of all possible subgraphs could be significant in the context of protein classification. To address these challenges, we have developed an information theoretic model called coherent subgraph mining. From information theory, the entropy of a random variable X measures the information content carried by X and the Mutual Information (MI) between two random variables X and Y measures the correlation between X and Y. We define a subgraph X as coherent if it is strongly correlated with every sufficiently large sub-subgraph Y embedded in it. Based on the MI metric, we have designed a search scheme that only reports coherent subgraphs. To determine the significance of coherent protein subgraphs, we have conducted an experimental study in which all coherent subgraphs were identified in several protein structural families annotated in the SCOP database (Murzin et al, 1995). The Support Vector Machine algorithm was used to classify proteins from different families under the binary classification scheme. We find that this approach identifies spatial motifs unique to individual SCOP families and affords excellent discrimination between families.

[An experimental study on the recombinant composite skin graft consisting of human epithelium and acellular xeno-dermis]

OBJECTIVE

To observe the effects of the recombinant composite skin graft consisting of human epithelium and acellular xeno-dermis on full thickness skin loss wounds, so as to find a new wound covering material.

METHODS

Forty-two nude mice with full thickness skin loss on the back were grafted with the composite skin (compound skin grafting group, G) and human keratinocyte sheet (control group, C), respectively. The wound healing conditions, such as wound healing rate and wound contraction rate, were observed at different time points after the operation. Simultaneously, wound tissue samples were harvested for histological examination.

RESULTS

The wound healing rate in G group was much higher than that in C group. In contrast, the wound contraction rate in G group was obviously lower than that in C group (P < 0.05). It was indicated by histological examination that there was full differentiation of epithelium, orderly collagen proliferation and obvious reconstruction of the epithelial-dermal conjunction structure in G group. There was no obvious sign of acute immune rejection.

CONCLUSION

The wound covering with recombinant composite skin graft of human epithelium and acellular xeno-dermis could improve wound healing quality. The composite skin could be a new skin substitute.

[The effects of rhGH on macrophages in scalded mice]

OBJECTIVE

To investigate the effects of rhGH and IGF-1 on the CD14 mRNA expression and cytokine secretion of peritoneal macrophages (Mphi) in scalded rats.

METHODS

Reverse-transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosordent assay (ELISA) were employed to observe the postburn changes of CD14 expression and cytokines secretion of the Mphi treated in vivo and in vitro by rhGH and IGF-1.

RESULTS

It was demonstrated that in vivo postburn application of rhGH and IGF-1 could enhance the transcription of CD14 mRNA and the secretion of cytokines from the peritoneal Mphi in mice. But it seemed that there was no additive effect between the two factors. Additionally, rhGH (at 40 ng/ml) and IGF-1 (at all tested concentrations) could activate the secretion of TNF and IL-6 from cultured mice Mphi in vitro.

CONCLUSION

Postburn application of rhGH might activate Mphi by IGF-1 induction, enhancing Mphi CD14 expression, which promoted more secretion of cytokines, and promote the enhancement of immune function.

Inhibition of breast and brain cancer cell growth by BCCIPalpha, an evolutionarily conserved nuclear protein that interacts with BRCA2

BRCA2 is a tumor suppressor gene involved in mammary tumorigenesis. Although important functions have been assigned to a few conserved domains of BRCA2, little is known about the longest internal conserved domain encoded by exons 14-24. We identified a novel protein, designated BCCIPalpha, that interacts with part of the internal conserved region of human BRCA2. Human BCCIP represents a family of proteins that are evolutionarily conserved, and contain three distinct domains: an N-terminus acidic domain (NAD) of 30-60 amino acids, an internal conserved domain (ICD) of 180-220 amino acids, and a C-terminus variable domain (CVD) of 30-60 amino acids. The N-terminal half of the human BCCIP ICD shares moderate homology with regions of calmodulin and M-calpain, suggesting that BCCIP may also bind Ca. Human cells express both a longer, BCCIPalpha, and a shorter, BCCIPbeta, form of the protein, which differ in their CVD. BCCIP is a nuclear protein highly expressed in testis. Although BCCIPbeta expression is relatively consistent in cancer cells, the expression of BCCIPalpha varies in cancer cell lines. The BCCIPalpha gene is located at chromosome 10q25.3-26.2, a region frequently altered in brain and other cancers. Furthermore, expression of BCCIPalpha inhibits breast and brain cancer cell growth, but fails to inhibit HT1080 cells and a non-transformed human skin fibroblast. These results suggest that BCCIPalpha is an important cofactor for BRCA2 in tumor suppression.

Interactions in sheep between tall fescue ergot alkaloids and hepatotoxic carbon tetrachloride and Senecio pyrrolizidine alkaloids

The interaction between ergot alkaloids in endophyte-infected (E+) tall fescue (Festuca arundinacea) seed and pyrrolizidine alkaloids (PA) in tansy ragwort (TR; Senecio jacobaea) when simultaneously fed to sheep was investigated. Because of the hepatogenic effects of prolactin (PRL), it was hypothesized that low serum PRL induced by ergot alkaloids would increase the susceptibility of sheep to hepatotoxicity induced by PA. Sheep are normally resistant to PA-induced hepatotoxicity. Twenty-four wether lambs weighing 34.1 +/- 2.3 kg were used after being randomly assigned to 1 of 6 treatments of 4 wethers each. The diets offered were a control basal diet containing endophyte-free (E-) tall fescue seed, control + carbon tetrachloride (CCL4), E+ tall fescue basal diet, E+2CCl4, E(-)+TR, or E+2TR. The diets were composed of 50% alfalfa meal, 34.5% rolled barley, 5% soybean meal, 4% cane molasses, 0.5% trace mineralized salt and 6% tall fescue (E- or E+) seed. In the 2 TR treatments 25% of the alfalfa was replaced by TR. Interaction between ergot alkaloids in E+ tall fescue and PA in TR was assessed by gamma glutamyl transferase (GGTP) activity and/or sulfobromophthalein (BSP) clearance rate, both of which measure liver function. Serum GGTP activity was measured on days 14 and 28; plasma BSP clearance was monitored on days 28 and 70 by collection of blood at 4, 8 and 16 min after i.v. BSP injection. Serum PRL assays were performed on days 14, 70 and 84. Serum GGTP activity was elevated by CCl4 drenching on days 14 and 28. On day 28 TR feeding reduced GGTP activity, but there was no difference between the 2 TR treatments. There was no difference in the mean BSP half-times (t1/2) and % BSP retentions on day 28 among any of the 6 treatments. On day 70, there was no difference in the t1/2 or % BSP retention 4 min after BSP injection among any of the treatments. At 8 min after BSP injection, however, % BSP retention was significantly higher for the control +CCl4 than for the E+2CCl4 treatment. At 16 min after BSP injection, the E+ treatment had a higher mean % BSP retention value than the E+2CCl4 treatment; there were no differences among the other treatments. Serum PRL levels were reduced by E+ or CCl4 on all 3 dates of PRL evaluation. The lack of interaction between ergot alkaloids in E+ tall fescue seed and PA in TR as assessed by GGTP activity and/or BSP clearance in sheep may imply that the target sites o the 2 alkaloids are metabolically different. The low serum PRL with E+ did not increase susceptibility of sheep to CCl4 or PA.

[Activation of L-Arg: no pathway in canine brain by the damage from complete cerebral ischemia-reperfusion]

To ascertain whether complete cerebral ischemia-reperfusion activate L-Arg: NO pathway in canine brain, we anestherized nine adult dogs with ketamine and fentayle and randomly divided into two groups. Four dogs were nonischemic control group. Five dogs were complete cerebral ischemia-reperfusion group, they underwent a 18-minute cardiac arrest, and were resusciatation by standard CPR, supported by intensive care for 8 hours. At the end of each experiment, the parietal cortex was assayed for content of Nitrite and NADPH-positive neurons. Compared with the control group, the contents of Nitrite and NADPH-positive neurons of coxtex in complete cerebral ischemia-reperfusion group increased significantly (P < 0.01). The results suggest that complete cerebral ischemia-reperfusion activate the L-Arg: NO pathway in canine brain, and NO may play an important role in cerebral ischemia-reperfusion injury.

[Effects of thermal injury on heart sialic acid content in rats]

The myocardial sialic acid content, ATPase activities, and Ca2+ level were investigated in rats with full thickness burn of 30% TBSA. The results showed that the burned rats had a decreased level of myocardial sialic acid which was only 58.8% of controls at 3 h postburn. Myocardial Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase and Ca(2+)-ATPase activities were inhibited in burned rats. As compared to controls, the burned rats showed a higher level of Ca2+ in heart tissue. This study indicated that there were abnormal energy metabolism, dysfunction of ion pump, and paradox Ca2+ overload in burned rats, which may be associated with the decrease in sialic acid content in myocardium.

[Effects of thermal injury on production of nitric oxide in rat heart]

To elucidate the relationship between thermal injury and production of nitric oxide (NO), we measured the levels of heart No2-/NO3- (the stable and products of NO) and GMP in rats with full thickness burn of 30% TBSA. A higher level of heart tissue NO2-/NO3- was observed from 3 to 24 hours after burn injury. Parallel to the changes of NO2-/NO3-, there were increases of tissue cGMP level and heart tissue water content in burned rats. L-NMMA, a specific inhibitor of NO synthetase (NOS), can block the rise of heart NO2-/NO3- and the enhancement of heart water content. The results indicate that the heart injury caused by burn injury may be associated with induction of NOS and formation of NO.

[Effect of lysostaphin on phagocyte function in burn mice]

The ability of lysostaphin to prevent immunosuppression of phagocyte was assessed in burn mice. A full thickness burn covering 20% of TBSA was created on back of mouse, Lysostaphin was given intraperitoneally (400 micrograms/kg/day) for 3 days in treatment group. The results showed that lysostaphin treatment could restore the depression of phagocytosis of chick RBC by peritoneal macrophages. In the group treated by lysostaphin, peritoneal macrophage chemiluminescence expressed much greater peak value than that in both burn and normal groups. The a-value, which is a criterion of carbon clearance, was 1.63 x 10(-2) in lysostaphin treated mice, while that in burn and normal mice were 8.13 x 10(-4) and 2.76 x 10(-3), respectively. Results of the study indicated that lysostaphin was effective in improving phagocytosis by phagocytes.

[Changes in myocardial ATPase activity and Ca2+ content in burned rats]

The myocardial ATPase activity and Ca2+ content were investigated in rats with full thickness skin burn injury of 30% TBSA. The results showed that there were significant inhibitions of Na+, K(+)-ATPase,Ca2+, Mg(2+)-ATPase, and Ca(2+)-ATPase activities of myocardium after burn injury. The burn injury could result in increase of calcium content in myocardium. Burned rats also had a higher level of MDA in heart tissue when compared to controls. This study demonstrates that the membrane defects with respect to ATPase activity, oxygen free radical, and Ca2+ overload in myocardium may be associated with damage of myocardium after burns.

Protein kinase C isoforms in muscle cells and their regulation by phorbol ester and calpain

Objectives were to identify the PKC isoforms in cultured muscle cells, to examine roles of Ca(2+)-dependent proteinases (calpains) in processing of various muscle PKC isozymes and to obtain a mechanistic description of the processing of PKCs by examining the temporal relationships between phorbol ester-dependent translocation of muscle PKCs and calpains between cytosolic and membrane compartments. Using six isoform (alpha, beta, gamma, delta, epsilon, zeta)-specific polyclonal antibodies, PKC alpha, delta and zeta were detected in rat skeletal muscle and in L8 myoblasts and myotubes. PKC alpha and zeta were primarily localized in the cytosolic fraction of L8 myotubes whereas PKC delta was more abundant in the membrane fraction. Phorbol ester (TPA) caused rapid depletion of myotube PKC alpha and PKC alpha and PKC delta isoforms from the cytosolic compartment and rapid appearance of these isoforms in the membrane fraction. However, long-term exposure of myotubes to TPA eventually caused down-regulation of PKCs in the membrane compartment. Down-regulation of PKCs in the membrane fraction was partially blocked by calpain inhibitor II. However, the rapid TPA-dependent cytosolic depletion of PKCs was unaffected by calpain inhibitor. This suggests that calpains may be responsible for membrane-associated down-regulation of PKCs but not for cytosolic depletion. In the final study we assessed the effects of phorbol ester on compartmentation of m-calpain with PKCs in muscle cells. Like the PKCs, TPA caused rapid association of m-calpain with the membrane fraction followed by down-regulation. This demonstrates that phorbol esters cause translocation of both PKCs and calpains to membranes where processing of PKCs may occur via the limited proteolysis exerted by calpains.

[The character and clinical application of glutaraldehyde cross-linked collagen artificial skin]

The glutaraldehyde cross-linked collagen artificial skin was made with the modified Burke's method. It is an ideal artificial skin in that animal tests proved that it has the effect of bacteriostasis with strong adhesiveness and good porosity, is capable of decreasing vaporization and the loss of protein and electrolyte, and without rejection reaction. Clinical use of the artificial skin in 30 patients resulted in an average healing time of 24 +/- 3 days of the eschar-excised wound covered with the artificial skin and autograft of skin seeds. It is especially effective in Pseudomonas aeruginosa infected wound and chronic ulcer.

Dietary pyrrolizidine (Senecio) alkaloids and tissue distribution of copper and vitamin A in broiler chickens

The effect of feeding a diet containing 5% tansy ragwort (TR) (Senecio jacobaea), a poisonous plant containing pyrrolizidine alkaloids (PA), on the blood and liver levels of copper, zinc, iron and vitamin A in broiler chicks was examined. Serum and liver copper and liver iron concentrations were increased in chicks fed a diet with 5% TR, while serum and liver zinc and vitamin A decreased. When PA were removed from the diet, partial restoration of normal serum vitamin A level occurred, indicating that the ability to mobilize liver vitamin A is not irreversibly inhibited by PA. The decline in serum vitamin A occurred by 8 days of TR feeding with a concurrent decline in growth rate. When chicks were fed a diet high in vitamin A (25,000 IU/kg), followed by a basal diet containing TR, serum vitamin A levels were significantly (P < 0.01) decreased, while liver vitamin A level increased. This indicates that mobilization of previously stored vitamin A from the liver is impaired by PA. Prior feeding of a high vitamin A level resulted in protective effects against PA toxicity, as assessed by histopathology. This study shows that a dietary source of PA modifies metabolism and tissue distribution of minerals and vitamin A.