The Pathogenicity of Fusobacterium nucleatum Modulated by Dietary Fibers-A Possible Missing Link between the Dietary Composition and the Risk of Colorectal Cancer

The dietary composition has been approved to be strongly associated with the risk of colorectal cancer (CRC), one of the most serious malignancies worldwide, through regulating the gut microbiota structure, thereby influencing the homeostasis of colonic epithelial cells by producing carcinogens, i.e., ammonia or antitumor metabolites, like butyrate. Though butyrate-producing Fusobacterium nucleatum has been considered a potential tumor driver associated with chemotherapy resistance and poor prognosis in CRC, it was more frequently identified in the gut microbiota of healthy individuals rather than CRC tumor tissues. First, within the concentration range tested, the fermentation broth of F. nucleatum exhibited no significant effects on Caco-2 and NCM460 cells viability except for a notable up-regulation of the expression of TLR4 (30.70%, p < 0.0001) and Myc (47.67%, p = 0.021) and genes encoding proinflammatory cytokines including IL1B (197.57%, p < 0.0001), IL6 (1704.51%, p < 0.0001), and IL8 (897.05%, p < 0.0001) in Caco-2 cells exclusively. Although no marked effects of polydextrose or fibersol-2 on the growth of F. nucleatum, Caco-2 and NCM460 cells were observed, once culture media supplemented with polydextrose or fibersol-2, the corresponding fermentation broths of F. nucleatum significantly inhibited the growth of Caco-2 cells up to 48.90% (p = 0.0003, 72 h, 10%) and 52.96% (p = 0.0002, 72 h, 10%), respectively in a dose-dependent manner. These two kinds of fibers considerably promoted butyrate production of F. nucleatum up to 205.67% (p < 0.0001, 6% polydextrose at 24 h) and 153.46% (p = 0.0002, 6% fibersol-2 at 12 h), which explained why and how the fermentation broths of F. nucleatum cultured with fibers suppressing the growth of Caco-2 cells. Above findings indicated that dietary fiber determined F. nucleatum to be a carcinogenic or antitumor bacterium, and F. nucleatum played an important role in the association between the dietary composition, primarily the content of dietary fibers, and the risk of CRC.

[Genetic diagnosis of microcephaly]

Objective: To explore the diagnostic value of chromosome karyotype analysis, chromosomal microarray analysis (CMA) and whole exome sequencing (WES) in microcephaly. Methods: A total of 9 cases of microcephaly fetuses diagnosed by prenatal ultrasound or children with microcephaly diagnosed after birth were selected from the Sixth Affiliated Hospital of Guangzhou Medical University from January 2014 to August 2022.Karyotype analysis and/or CMA were used to detect. The cases with negative karyotype analysis and CMA results were further sequenced by trio-based WES (Trio-WES). Then the coding genes contained in the pathogenic copy number variation (CNV) fragments were analyzed by gene ontology (GO) enrichment. The genes related to the development of the central nervous system contained in the pathogenic CNV and the pathogenic genes found by Trio-WES were combined for gene interaction network analysis. Results: In this study, 9 cases of microcephaly were recruited, with the time of diagnosis ranged from 23 weeks of gestation to 7 years after birth, and the head circumference of fetus or children ranged from 18.3 to 42.5 cm (-7SD to -2SD). Karyotype analysis was detected in all 9 cases and no abnormality result was found. Eight cases were detected by CMA, and one abnormal was found. Five cases were detected by Trio-WES, and two cases were detected with likely pathogenic genes. The GO enrichment analysis of the coding gene in the 4p16.3 microdeletion (pathogenic CNV) region showed that: in biological process, it was mainly concentrated in phototransduction, visible light; in terms of molecular function, it was mainly concentrated in fibroblast growth factor binding; in terms of cell components, it was mainly concentrated in rough endoplasmic reticulum. Gene interaction network analysis suggested that CDC42 gene could interact with CTBP1, HTT and ASPM gene. Conclusions: CMA could be used as a first-line detection technique for microcephaly. When the results of chromosome karyotype analysis and/or CMA are negative, Trio-WES could improve the detection rate of pathogenicity of microcephaly.

Screening of a novel autophagy-related prognostic signature and therapeutic targets in hepatocellular carcinoma

BACKGROUND

Many studies have indicated that autophagy plays an important role in multiple cancers, including hepatocellular carcinoma (HCC). This study aimed to establish a prognostic signature for HCC based on autophagy-related genes (ARGs) to predict the prognosis of patients.

METHODS

The list of ARGs was derived from screening National Center for Biotechnology Information (NCBI)-Gene and Molecular Signatures Database (MSigDB) datasets. Differential analysis was conducted via the R limma package in HCC patients based on The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analysis were conducted to identify key prognostic ARGs via the survival package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed by clusterProfiler package. The Estimation of Stromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) algorithm was used to conduct immune analysis. Finally, the correlation between the prognostic model and clinical characteristics was also assessed, including age, tumor-node-metastasis (TNM) stages, and tumor grades.

RESULTS

Firstly, 106 differential ARGs were identified and 10 candidates were further confirmed via Cox regression analysis, including BAMBI, HIF1A, SERPINE1, EZH2, SLC9A3R1, IGFBP3, HSPB8, DAB2, CXCL1 and PRNP. The receiver operating characteristic (ROC) curve analysis revealed that the ARGs risk model had a well diagnostic positive rate with 1-year area under the curve (AUC) =0.688 and 3-year AUC =0.674. Correlation analysis indicated that only advanced tumor stages were positively associated with high ARGs scores with P=0.0227. There were also significant differences in tumor purity (P=6.71e-05), infiltrating cell analysis (P=7.77e-05), immune analysis (P=7.9e-05), and stromal cells analysis (P=0.0015) in high- and low-risk ARGs samples. The genes HIF1A, IGFBP3, and DAB2 were found to have high frequent missense mutations in samples with high-risk ARGs scores. Lastly, we also established a nomogram to predict overall survival (OS) of HCC by integrating ARGs scores and other clinical parameters.

CONCLUSIONS

Our study established an autophagy-related signature for predicting the prognosis of HCC patients, providing a thorough understanding of the underlying mechanisms of autophagy in HCC.

[NEK2 gene expression in mouse cryptorchidism model and its mechanism involved in apoptosis]

Objective: To observe the expression of NEK2 mRNA and protein in the cryptorchidism mice model, and to explore its role in apoptosis of testicular tissue. Methods: A mouse cryptorchid model was constructed, and the spermatids in the spermatic tubules were observed by HE staining. Apoptosis was detected by Tunel test, and expression of NEK2 mRNA and protein was detected by RT-PCR and immunohistochemistry, respectively. Results: After the mouse cryptorchidism model was successfully constructed, the HE staining results showed that the damage of spermatogonia cells, primary spermatocytes and sperm cells in the seminiferous tubules became more severe with time. The results of Tunel test showed that the number of apoptotic cells first increased and then decreased, 1, 3, 6, 9 and 15 d apoptotic cells were 3.67±2.08 (t=2, P=0.0412), 7.67±1.53 (t=6.325, P=0.003), 17.67±3.51 (t=7.906, P=0.001), 30.67±3.51 (t=14.072, P<0.001) and 14.33±3.21 (t=6.860, P=0.002). The results of immunohistochemistry showed that NEK2 protein was expressed in the nucleus and cytoplasm in normal testis and cryptorchidism. RT-PCR and immunohistochemistry showed that expression of NEK2 mRNA and protein gradually increased after modeling. After reaching the peak, the expression gradually decreased with time, and was significantly lower than the normal control group. Conclusion: The trend of NEK2 expression in cryptorchidism tissue is consistent with the trend of cell apoptosis in cryptorchidism tissue, suggesting that abnormal expression of NEK2 may affect the damage of sperm cells in the seminiferous tubules through apoptosis, leading to infertility in patients with cryptorchidism.

Gender differences in vascular reactivity of mesenteric arterioles in portal hypertensive and non-portal hypertensive rats

BACKGROUND

Portal hypertension (PHT) is primarily caused by an increase in resistance to portal outflow and secondarily by an increase in splanchnic blood flow. Vascular hyporeactivity both in systemic circulation and in the mesenteric artery plays a role in the hyperdynamic circulatory syndrome.

AIM

To explore gender differences and the role of endogenous sex hormones in PHT and vascular reactivity of mesenteric arterioles in rats.

METHODS

Cirrhosis and PHT were established by subcutaneous injection of carbon tetrachloride (CCl₄) in both male and female integral and castrated rats (ovariectomized [OVX] in female rats, orchiectomy [ORX] in male rats). The third-order branch of the mensenteric artery was divided and used to measure vascular reactivity to vasoconstrictors.

RESULTS

No significant difference in portal pressure was observed between integral and castrated male PHT rats (15.2 ± 2.1 mmHg vs 16.7 ± 2.7 mmHg, P > 0.05). The portal pressure in integral female PHT rats was lower than that in OVX female PHT rats (12.7 ± 2.7 mmHg vs 16.5 ± 2.4 mmHg, P < 0.05). In PHT rats, the concentration response curves of the mesenteric arterioles to norepinephrine were shifted to the right, and the maximal responses (E_max) values were decreased and effective concentrations causing half maximum responses (EC₅₀) values were increased, compared to those of non-PHT rats, both in male and female rats. Compared to non-PHT integral male rats, the sensitivity of the mesenteric arterioles of non-PHT ORX male rats to norepinephrine was decreased (P > 0.05). However, there was no difference between integral and ORX male rats with PHT. In integral female PHT rats, the concentration response curves were shifted to the left (P < 0.05), and the E_max values were increased and EC₅₀ values were decreased compared to OVX female PHT rats.

CONCLUSION

Clear gender differences were observed in mesenteric vascular reactivity in CCl₄-induced cirrhotic and PHT rats. Conservation of estrogen can retain the sensitivity of the mesenteric arterioles to vasoconstrictors and has a protective effect on splanchnic vascular function in PHT.

[The expression of VHL/HIF signaling pathway in the erythroid progenitor cells with chronic mountain sickness]

Objective: To investigate the expression and interaction of VHL/HIF-α pathways including HIF-1α, HIF-2α as well as VHL in erythroid progenitor cells of bone marrow from chronic mountain sickness (CMS) patients. Methods: A total of 25 patients with CMS and 21 healthy controls were recruited for this study. The CD71(+)CD235a(+) cells in bone marrow mononuclear cells, marked as erythroid progenitor cells, were isolated using MACS separation technology. The expression levels of HIF-1α, HIF-2α and VHL in erythroid progenitor cells were detected by Western blotting and real-time fluorescence quantitative PCR. Results: The mRNA levels of HIF-2α were higher in erythroid progenitor cells of CMS than in healthy controls [1.68 (0.81, 2.22) vs 0.98 (0.60, 1.19), P<0.05], while HIF-1α and VHL mRNA levels were similar between the two groups (P>0.05). Spearman analyses indicated that HIF-2α mRNA was positively associated with hemoglobin (Hb) levels in the erythroid progenitor cells of CMS (ρ=0.504, P<0.05). Furthermore, the mRNA level of HIF-2α was correlated with the mRNA level of VHL in the erythroid progenitor cells of CMS (ρ=0.647, P<0.05).The protein levels of HIF-2α in the erythroid progenitor cells of CMS were higher than that of healthy controls [0.94(0.68, 3.30) vs 0.59(0.30, 0.88), P<0.05], but the protein levels of HIF-1α and VHL were similar between the two groups (P>0.05). Conclusions: The abnormal increased expression of HIF-2α in the erythroid progenitor cells of CMS patients leads to the abnormal expression of hypoxia sensitive genes downstream, participating in the occurrence and development of CMS.

[Effect of ERK1/2 Signaling Pathway Inhibitor PD98059 on the Expression of Ras, BRaf, MEK, ERK1/2 in Marrow Nucleated Red Blood Cells of CMS Patients]

OBJECTIVE

To investigate the effect of ERK1 / 2 signaling pathway inhibitor PD98059 on Ras, Raf, MEK, ERK1, ERK2 expression in order to explore a new way for basic research and clinical treatment of the chronic mountain sickness(CMS).

METHODS

Sixteen CMS patients were selected, the bone marrow was collected for isolation of monomuclear cells (MNC), the cells were sorted by using CD71 and CD235a antibody magnetic beads, then positive cells were diveded into 5 groups: blank control, DMSO and PD98059 5, 10 and 20 µmol/L, and were cultured in hypoxid condition for 72 hours. The Ras-GTP levels in supernatant was detected by ELISA, the RT-PCR was used to determine the expression of BRaf, MEK, ERK1, ERK2 mRNA in nucleated red blood cells, and the Western blot method was used to detect expression of BRaf, MEK, ERK1, ERK2 protein.

RESULTS

PD98059 had no effect on the level of Ras-GTP in each groups. Compared with the blank control group, the expression levels of BRaf, MEK mRNA in DMSO group were not statistically significant (P values were 0.826, 0.298). Compared with the PD98059 20 mol/L group, the expression level of ERK1/2 mRNA was statistically significant (P=0.001, 0.002). Compared with the blank control group, expression levels of p-BRaf, p-MEK protein in DMSO group were not statistically significant (P=0.370, 0.351). Compared with the PD98059 20 mol/L group, the difference of p-ERK1/2 protein level in other 4 groups were statistically significant (P values were <0.001, 0.007).

CONCLUSION

PD98059 can up-regulate the expressions of ERK1/2 miRNA and p-ERK1/2 protein in bone marrow nucleated red blood cells, the Ras / Raf / MEK / ERK 1/2 pathway is the main signal transduction pathway in regulating bone marrow nucleated red blood cells, suggesting that Ras/Raf /MEK /ERK 1/2 pathway may be involved in the pathogenesis of chronic mountain sickness process.

[The expressions of VEGF and VEGFR signaling pathway in the bone marrow mononuclear cells with chronic mountain sickness]

Objective: This study was aimed at investigating the levels and relationships of vascular endothelial growth factor (VEGF) and its receptor(VEGFR) in the bone marrow mononuclear cells (MNC) of chronic mountain sickness (CMS). Methods: A total of 34 patients with CMS and 30 controls residing at altitudes of 3 000-4 500 m were recruited for this study. The levels of VEGF, VEGFR1 and VEGFR2 in bone marrow MNC were detected by flow cytometry technique and RT-qPCR. Results: The percentage of VEGFR2 positive cells in the bone marrow MNC of CMS were higher than that of the controls[20.7% (8.1%, 67.6%) vs 8.1% (2.2%, 14.9%), P<0.05], but that of VEGFR1-positive and VEGF-positive were similar in CMS and controls. The mRNA levels of VEGFR2 were higher in the bone marrow MNC of CMS than in the controls[1.7(1.0, 5.1) vs 1.0(0.4, 2.7), P<0.05], while VEGF and VEGFR1 mRNA levels were similar between the two groups. The percentage of VEGFR2 positive cells in CMS were significantly correlated with hemoglobin (r=0.453, P=0.007) and the percentage of VEGF-positive cells (r=0.373, P=0.030). Conclusions: Bone marrow MNC of CMS may show enhanced activity of the VEGF-VEGFR2 pathway, and it appears to be involved in the pathogenesis of CMS.

Estrogen receptor β selective agonist ameliorates liver cirrhosis in rats by inhibiting the activation and proliferation of hepatic stellate cells

BACKGROUND AND AIM

The aim of this study is to explore the roles of estrogen receptor (ER) subtypes and corresponding agonists/antagonists on the development of cirrhosis and activation and proliferation of hepatic stellate cells (HSCs).

METHODS

Carbon tetrachloride (CCl₄ )-induced cirrhotic ovariectomized rats were administered non-selective ER agonist (β-estradiol, E2), ER selective agonists (ERα agonist, propylpyrazoletriol; ERβ agonist, diarylpropionitrile [DPN]; and G-protein-coupled ER [GPER] agonist, G1), or E2 + ER selective antagonists (ERα antagonist, MPP; ERβ antagonist, PHTPP; and GPER antagonist, G15) for 12 weeks. The expression of the three ER subtypes in livers and HSCs and the effects of the drugs on hepatic fibrosis, isolated HSCs, and uteri were evaluated.

RESULTS

Selective ER agonists/antagonists had various effects on CCl₄ -induced cirrhosis. The cirrhotic rats in the CCl₄  + E2, CCl₄  + DPN, CCl₄  + E2 + MPP, and CCl₄  + E2 + G15 groups presented reduced fibrosis scores, compared with those in the CCl₄ group. The cirrhotic rats in the E2 + PHTPP group presented increased fibrosis scores that similar to those in the CCl₄ group. The ovariectomized rats had enlarged uteri with increased uterus indexes after E2 administration; however, the proliferative effects of E2 were partially blocked by MPP or G15, but not PHTPP. In the in vitro study, DPN attenuated the transformation of quiescent HSCs to activated phenotype, suppressed collagen I, and α-smooth muscle actin expression. DPN also suppressed platelet-derived growth factor-induced proliferation in cultured HSCs, which was reversed by PHTPP.

CONCLUSIONS

The antifibrogenic effects of estrogen were mediated by ERβ but not ERα or GPER. The ERβ selective agonist exerted a fibrosuppressive effect by inhibiting the activation and proliferation of HSCs, but did not induce uterine hyperplasia.

[Influence of HIF- 2α on the expression of GATA- 1 in bone marrow CD71(+) cell of high altitude polycythemia rat model]

OBJECTIVE

To explore the influence of hypoxia-inducible factor-2 αlpha (HIF-2α) on the expression of erythroid-specific transcription factor GATA-1 in bone marrow CD71(+) cells of rat model with high altitude polycythemia (HAPC).

METHODS

A total of 48 male SD rats were selected and randomly divided into normal control group and HAPC group. HAPC model was established at an altitude of 4 300 meters in the natural environment and verified by bone marrow cell classification and counting, hematologic parameters and serum EPO detection. Bone marrow CD71 (+) cells were separated by a combination of methods with density gradient centrifugation and magnetic activated cell sorting. The changes of expression level of HIF-2α, GATA-1 mRNA and proteins were detected by Q-PCR and Western blot. CD71 (+) cells were cultured under hypoxia condition and transfected with selected optimal HIF- 2α shRNAi3 for 96 h. And the expression level of HIF-2α and GATA-1 mRNA and proteins were detected by Q- PCR and Western blot.

RESULTS

The results of bone marrow cell counts, the hematologic parameters and the serum EPO content showed that the HAPC rat model was successfully established. The expression of HIF-2α and GATA-1 mRNA and protein in bone marrow CD71(+) cells of HAPC group was higher than that in control group (P<0.05). And HIF-2α and GATA-1 of HAPC group were positively correlated at the expression levels of mRNA and protein, respectively (r=0.923, P<0.01; r=0.838, P<0.01). However, the expression of HIF-2α and GATA-1 mRNA and protein in HAPC group was significantly lower than that in control groups after interfered by HIF-2α shRNAi3 for 96 h (P<0.05).

CONCLUSION

The effect of HIF-2α on GATA-1 expression may be correlated with the pathogenesis of HAPC.

[Effect of Rabbit Anti-human Thymocyte Immunoglobulin Combined with Cyclosporin A on Severe Aplastic Anemia]

OBJECTIVE

To study the efficacy and safety of anti-human thymocyte immunoglobulin(ATG-F) combined with cyclosporin A(CsA) on patients with severe aplastic anemia (SSA), so as to provide support for clinical work.

METHODS

From January 2010 to December 2015, 78 patients with SAA admitted in our hospital were divided into 2 groups: ATG-F+CsA group(40 cases) and ATG-F group(38 cases). After treatment for 6 months, the effective rate, side reaction rate and time of effect initiation were compared between 2 groups. The follow-up results were compared between 2 groups.

RESULTS

The effective rate and side reaction rate in ATG-F+CsA group were 100.00% and 32.50% respectively, those in ATG-F group were 94.74% and 44.74% respectively and without statistical significant difference(P>0.05). In ATG-F+CsA group, the time of effect initiation in cured patients, remission and obvious inprovement were (44.9±15.4) d, (68.8±15.9) d and (85.4±17.6) d; in ATG-F group, patients with those were (59.6±11.5) d, (94.7±17.8) d and (119.8±21.4) d respectively, the difference showed statistical significance(P<0.05). The follow-up results were not statistically significantly different between 2 groups(P>0.05).

CONCLUSION

ATG-F combined with CsA can shorten the time of effect initiation, and demonstrates reliable safety.

[Influence of GATA-1 on Expression of EpoR in Bone Marrow CD71+ Cells of Rat Model with High Altitude Polycythemia]

OBJECTIVE

To explore the influence of GATA-1 on expression of EpoR in bone marrow CD71+ cells of rat model with high altitude polycythemia (HAPC).

METHODS

Forty-eight male SD rats were randomly divided into normal control and HAPC model group. HAPC model was established at the altitude of 4 300 meters in the natural environment, and verified by bone marrow cell counts and hematological parameters. Myeloid CD71+ cells were separated by the density gradient centrifugation combined with magnetic activated cell sorting. The expression of EpoR on cell membrane was detected by flow cytometry and cell immunofluorescence. The expression changes of GATA-1 and EpoR mRNA and protein were detected by Q-PCR and Western blot, respectively. CD71+ cells were cultured under normoxia and hypoxia, respectively. After transfection for 96 h, the optimal interference sequence GATA-1 shRNA1 was selected. And the mRNA and protein expression level of GATA-1 and EpoR were detected by Q-PCR and Western blot respectively.

RESULTS

The animal model with HAPC was established successfully and comfirmed by the bone marrow cell counting and the hematologic parameters in comparison with that of the normal control. EpoR expression on the myeloid CD71+ cell membrane in HAPC group was significantly higher than that in normal control (P<0.05). The expression of GATA-1 and EpoR in myeloid CD71+ cells of HAPC group was higher than that in control group (P<0.05). The mRNA and protein expression of GATA-1 and EpoR in two groups positively correlated (control group, r=0.929, P<0.01, r=0.802, P<0.05; HAPC group, r=0.822, P<0.05, r=0.839, P<0.01). However, the mRNA and protein expression of EpoR at normoxia and hypoxia was significantly lower than that in negative control group after interfernce with GATA-1 shRNA1 for 96 h (P<0.05). And the expression of GATA-1 and EpoR under hypoxia was higher than that in normoxia.

CONCLUSION

The effect of GATA-1 on EpoR expression may be correlated with the pathogenesis of HAPC.

[Clinical Therapeutic Efficacy of Rituximab Combined with Methotrexate on Primary Central Nervous System Lymphoma]

OBJECTIVE

To investigate the therapeutic efficacy of rituximab combined with methotrexate on patients with primary central nervous system lymphoma.

METHODS

Fifty eight patients with central nervous system lymphoma treated in our hospital from February 2008 to September 2011 years were randomly divided into the observation group and the control group. The control group was treated with methotrexate combined with whole brain radiotherapy; the observation group was treated by rituximab combined with methotrexate. The curative efficacy, adverse effects, life quality, and the 1 and 3 year survival rate after 2 cycles of treatment were compared between 2 groups.

RESULTS

The total effective rate of observation group was 82.76%, which significantly higher than 58.62% of the control group (P < 0.05). In observation group, the incidences of anemia, liver damage, gastrointestinal side effect and oral ulcer were significantly lower than that in control group, respectively (P < 0.05). The physiological function, physical function, health status, social and emotional function in the observation group were significantly higher than those in the control group (P < 0.05), 1 and 3 years survival rates in the observation group were 86.21% and 62.07%, significantly higher than 58.62% and 31.03% in the control group (P < 0.05).

CONCLUSION

Targeted therapy combined with chemotherapy for the primary central nervous system lymphoma can improve the patients' outcomes, reduce adverse effects, and improve the quality of life and survival rate.

[Effect of PD98059 on Proliferation and Apoptosis of CD71(+),CD235a(+) Nucleated Erythrocytes in the Patients with High Altitude Polycythemia]

Objective： To study the effect of PD98059, a specific inhibitor of Ras/Raf/MEK/ERK signaling pathway, on the proliferation and apoptisis of bone marrow CD71(+), CD235a(+) nucleated erythrocytes in patients with high altitude polycythemia (HAPC) and the pathogenesis of HAPC.

METHODS

The CD71(+) and CD235a(+) nucleated erythrocytes in HAPC patients and controls (patients with simple obsolete stracture) were sorted by using the immunemagnetic beads, then were added with 5, 10, 20 µmol/L of PD98059 and DMSO (as control) and were cultured for 72 h under hypoxia. The cell apoptosis was detected by flow cytometry with Annexin V and PI double staining, the cell proliferation was detected by CCK8 method, at same time the erythroid colong-formation ability of bone marrow mononuclear cells (BMMNC) treated with 5, 10, 20 µmol/L of PD98059 and DMSO was observed.

RESULTS

With the increase of PD98059 concentration, the apoptosis rate of bone marrow CD71(+) and CD235a(+) nucleated erythrocytes in HAPC patients was enhanced (r=0.807,P<0.01), while the proliferation rate of CD71(+) and CD235a(+) nucleated erythrocytes in HAPC patients dereased (r=0.502,P<0.01). The erythroid colong-formation ability of BMMNC in HAPC patients decreased with the increase of PD98059 concentration (r=0.504,P<0.01). There were statistic differences among different groups at 7 and 14 d.

CONCLUSION

The MEK specific inhibitor PD98059 can inhibit the proliferation and promote the apoptosis of CD71(+) and CD235a(+) nucleated erythrocytes in HAPC patients, then inhibit the excessive accumulation of erythrocytes.

Skp2-RNAi suppresses proliferation and migration of gallbladder carcinoma cells by enhancing p27 expression

AIM: To explore the role of S-phase kinase-associated protein-2 (Skp2) in gallbladder carcinoma and to identify whether depletion of Skp2 by Skp2-RNAi could attenuate proliferation and migration of gallbladder carcinoma.

METHODS: Skp2-RNAi was transduced into cells of the gallbladder carcinoma cell line GBC-SD, using a lentiviral vector. The effect of Skp2-RNAi on the proliferation, migration, invasion and cell cycle of GBC-SD cells was studied using in vitro assays for cell proliferation, colony formation, wound healing and cell cycle. The expression of Skp2 and p27 was detected by real-time polymerase chain reaction and Western immunoblotting. The effect of Skp2-RNAi on the proliferation of GBC-SD cells in vivo was investigated by tumorigenicity experiments in nude mice.

RESULTS: Lentivirus-mediated RNAi reduced the expression of Skp2 in cultured cells. The expression of the p27 protein increased along with the down-regulation of Skp2, although no significant difference was found in p27 mRNA expression. Flow cytometry revealed that Skp2-RNAi transfection significantly increased the proportion of cells in the S phase and significantly decreased the proportion of cells in the G₂/M phase. No significant difference in the frequency of cells in the G₀/G₁ phase was observed. The results from the cell proliferation, colony formation and wound healing assays revealed that Skp2-RNAi transfection markedly inhibited the proliferation and migration of GBC-SD cells in vitro. Additionally, tumorigenicity experiments showed that suppression of Skp2 significantly decreased the weights of the tumors (0.56 ± 0.11 and 0.55 ± 0.07 g in the control and Scr-RNAi groups vs 0.37 ± 0.09 and 0.35 ± 0.08 g in the Skp2-RNAi-L and Skp2-RNAi-H groups).

CONCLUSION: The expression of Skp2 in GBC-SD cells was inhibited following Skp2-RNAi transfection. Silencing of the Skp2 gene inhibited proliferation, migration and invasiveness of GBC-SD cells by mechanisms dependent on enhanced expression of the p27 protein.

[Changes of serum angiogenesis in patients with chronic mountain sickness]

AIM

The clinical manifestation of chronic mountain sickness (CMS) is polycythemia, pulmonary hypertension and mionectic blood. However, the pathogenesis of it is not identified now. So it is necessary to investigate the effects of the angiogenic growth factors on the pathophysiologic development of CMS.

METHODS

The serum levels of basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) in 13 healthy Tibetan natives (Native), 17 healthy people in Xining (control group) and 35 CMS patients were determined by quantitative sandwich enzyme immunoassay. Meanwhile, the levels of Hb, Hct and SaO2 were determined.

RESULTS

The serum levels of bFGF (107.26 +/- 7.86) ng/L, PDGF (630.18 +/- 9.89) ng/L and VEGF (543.74 +/- 6.76) ng/L in CMS were significantly higher than those in Natives (37.01 +/- 9.16; 292.16 +/- 6.88; 125.51 +/- 7.26) ng/L, and in control group (40.58 +/- 5.34; 287.68 +/- 8.33; 76.26 +/- 4.60) ng/L, respectively (P < 0.01). There was no difference between the natives and the control group in bFGF and PDGF (P > 0.05), while there was predominant difference between the Natives and the control group in VEGF (P < 0.01). There was a predominant positive correlation between the serum levels of bFGF, PDGF or VEGF and hemoglobin concentrations in CMS respectively (P < 0.01). And there were positive relations between angiogenic growth factors each other.

CONCLUSION

The serum levels of bFGF, PDGF and VEGF in patients with CMS significantly increase, these angiogenic growth factors may play important role on the pathophysiologic development of CMS; the VEGF level likely contributes to the adaptation to plateau hypoxia in healthy Tibetan natives; the elevated bFGF, PDGF and VEGF levels are likely associated with excessive erythropoiesis in CMS.

[Increment of chemokine CXCL9/Mig in plasma correlated with acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation]

To investigate the relationship between the plasma levels of chemokine CXCL9/Mig and acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The plasma levels of CXCL9/Mig of 35 patients who received all-HSCT were detected by using ELISA assay, these patients included 13 patients with grade 0-I, 12 patients with grade II and 10 patients with grade III - IV aGVHD, respectively. The four different time points including prior to allo-HSCT, one week before aGVHD onset, the plateau of aGVHD and time after completely controlled, were studied. The results showed that the plasma levels of CXCL9/Mig in the patients with serious aGVHD (grade II - IV) were significantly increased during aGVHD than those in the patients without aGVHD or with slight aGVHD (P < 0.001). It was found that CXCL9/Mig levels were significantly correlated with the severity of grade aGVHD (P < 0.001). Another important finding was that CXCL9/Mig levels obviously increased at one week before aGVHD was diagnosed. CXCL9/Mig level was not obviously correlated with CMV infection or other infectious complication (P > 0.05). It is concluded that the plasma level of CXC19/Mig significantly correlated with the severity of aGVHD and plays a critical role in pathogenesis of aGVHD, the changes in plasma level of CXCL9/Mig after allo-HSCT may be used as a valuable indicator for early diagnosis of aGVHD, finally, provide a early therapeutic approach to reduce aGVHD severity and improve the outcome for patients after allo-HSCT.

The suppressor of transgene RNA silencing encoded by Cucumber mosaic virus interferes with salicylic acid-mediated virus resistance

The Cucumber mosaic virus (CMV)-encoded 2b protein (Cmv2b) is a nuclear protein that suppresses transgene RNA silencing in Nicotiana benthamiana. Cmv2b is an important virulence determinant but nonessential for systemic spread in N. glutinosa, in contrast to its indispensable role for systemic infections in cucumber. Here, we report that Cmv2b became essential for systemic infections in older N. glutinosa plants or in young seedlings pretreated with salicylic acid (SA). Expression of Cmv2b from the genome of either CMV or Tobacco mosaic virus significantly reduced the inhibitory effect of SA on virus accumulation in inoculated leaves and systemic leaves. A close correlation is demonstrated between Cmv2b expression and a reduced SA-dependent induction of the alternative oxidase gene, a component of the recently proposed SA-regulated antiviral defense. These results collectively reveal a novel activity of Cmv2b in the inhibition of SA-mediated virus resistance. We used a N. tabacum line expressing a bacterial nahG transgene that degrades SA to provide evidence for a Cmv2b-sensitive antiviral defense mechanism in tobacco in which SA acts as a positive modifier but not as an essential component. We propose that SA induces virus resistance by potentiating a RNA-silencing antiviral defense that is targeted by Cmv2b.

Strong host resistance targeted against a viral suppressor of the plant gene silencing defence mechanism

The 2b protein encoded by cucumber mosaic cucumovirus (Cmv2b) acts as an important virulence determinant by suppressing post-transcriptional gene silencing (PTGS), a natural plant defence mechanism against viruses. We report here that the tomato aspermy cucumovirus 2b protein (Tav2b), when expressed from the unrelated tobacco mosaic tobamovirus (TMV) RNA genome, activates strong host resistance responses to TMV in tobacco which are typical of the gene-for-gene disease resistance mechanism. Domain swapping between Cmv2b, which does not elicit these responses, and Tav2b, revealed functional domains in Tav2b critical for triggering virus resistance and hypersensitive cell death. Furthermore, substitution of two amino acids from Tav2b by those found at the same positions in Cmv2b, Lys21-->Val and Arg28-->Ser, abolished the ability to induce hypersensitive cell death and virus resistance. However, in Nicotiana benthamiana, a species related to tobacco, Tav2b functions as a virulence determinant and suppresses PTGS. Thus, a viral suppressor of the host gene silencing defence mechanism is the target of another independent host resistance mechanism. Our results provide new insights into the complex molecular strategies employed by viruses and their hosts for defence, counter-defence and counter counter-defence.

Viral pathogenicity determinants are suppressors of transgene silencing in Nicotiana benthamiana

Post-transcriptional gene silencing (PTGS) of a green fluorescent protein (GFP) transgene is suppressed in Nicotiana benthamiana plants infected with potato virus Y (PVY) or with cucumber mosaic virus (CMV), but not in plants infected with potato virus X (PVX). By expressing PVY and CMV-encoded proteins in a PVX vector we have shown that the viral suppressors of gene silencing are the HCPro of PVY and the 2b protein of CMV. The HCPro acts by blocking the maintenance of PTGS in tissues where silencing had already been set, whereas the 2b protein prevents initiation of gene silencing at the growing points of the plants. Combined with previous findings that viruses are both activators and targets of PTGS, these data provide compelling evidence that PTGS represents a natural mechanism for plant protection against viruses.

Ilarviruses encode a Cucumovirus-like 2b gene that is absent in other genera within the Bromoviridae

We found that RNA 2 of the four ilarviruses sequenced to date encodes an additional conserved open reading frame (ORF), 2b, that overlaps the 3' end of the previously known ORF, 2a. A novel RNA species of 851 nucleotides was found to accumulate to high levels in plants infected with spinach latent virus (SpLV). Further analysis showed that RNA 4A is a subgenomic RNA of RNA 2 and encodes all of ORF 2b. Moreover, a protein species of the size expected for SpLV ORF 2b was translated in vitro from the RNA 4A-containing virion RNAs. The data support the suggestion that the SpLV 2b protein is translated in vivo. The 2b gene of ilarviruses, which is not encoded by alfamoviruses and bromoviruses, shares several features with the previously reported cucumovirus 2b gene; however, their encoded proteins share no detectable sequence similarities. The evolutionary origin of the 2b gene is discussed.

Toward a free-space parallel optoelectronic computer: a 300-MHz optoelectronic counter using holographic interconnects

We built and tested one of the key components of a free-space holographically interconnected stored-program optoelectronic computer: a counter. The counter is constructed with 1-ns-latency optoelectronic NOR gates and is interconnected with holographic optical elements. Two synchronization methods were also demonstrated: the gate-and-strobe method and the time-of-flight method. These counters represent prototypical optoelectronic finite-state controllers. They were developed to demonstrate the feasibility of providing optoelectronic controllers for optoelectronic processors.

An early meiosis cDNA clone from wheat

Meiosis occupies only a very short period of the life cycle of higher plants but it is a crucial process ensuring the correct passage and maintenance of genetic information from parent to offspring. A clone (designated pAWJL3) has been isolated from a cDNA library generated from RNA prepared from young wheat florets at early meiosis. The clone was identified through cross-hybridisation to a cDNA clone from maize that, in turn, had been isolated by hybridisation to a Lilium meiosis-specific cDNA clone. The genes encoding the sequence represented in the wheat cDNA clone have been assigned to chromosomes in wheat. The clone, pAWJL3, represents a small family of genes with about 20 members located on the short arms of group 3 and 5 chromosomes. The chromosomal regions harbour genes known to control chromosomal pairing in wheat. DNA prepared from a deletion mutation affecting one of the major genes controlling pairing, Ph2 located on the short arm of 3DS, lacks the 3DS-specific members of the pAWJL3 family bands. The genes are shown to be expressed only after leptotene and predominantly at zygotene and pachytene of meiosis I. The deduced amino acid sequence encoded by the cDNA clone shows two domains, one with three leucine-rich, 24-amino acid repeats and the other with four leucine heptad repeats that resemble those found in basic leucine zipper proteins.