Competing itinerant and local spin interactions in kagome metal FeGe

The combination of a geometrically frustrated lattice, and similar energy scales between degrees of freedom endows two-dimensional Kagome metals with a rich array of quantum phases and renders them ideal for studying strong electron correlations and band topology. The Kagome metal, FeGe is a noted example of this, exhibiting A-type collinear antiferromagnetic (AFM) order at TN ≈ 400 K, then establishes a charge density wave (CDW) phase coupled with AFM ordered moment below TCDW ≈ 110 K, and finally forms a c-axis double cone AFM structure around TCanting ≈ 60 K. Here we use neutron scattering to demonstrate the presence of gapless incommensurate spin excitations associated with the double cone AFM structure of FeGe at temperatures well above TCanting and TCDW that merge into gapped commensurate spin waves from the A-type AFM order. Commensurate spin waves follow the Bose factor and fit the Heisenberg Hamiltonian, while the incommensurate spin excitations, emerging below TN where AFM order is commensurate, start to deviate from the Bose factor around TCDW, and peaks at TCanting. This is consistent with a critical scattering of a second order magnetic phase transition with decreasing temperature. By comparing these results with density functional theory calculations, we conclude that the incommensurate magnetic structure arises from the nested Fermi surfaces of itinerant electrons and the formation of a spin density wave order.

Out-of-set association analysis of lung cancer drugs and symptoms based on clinical case data mining

BACKGROUND

There are 1.8 million lung cancer deaths worldwide, accounting for 18% of global cancer deaths, including 710,000 in China, accounting for 23.8% of all cancer deaths in China.

OBJECTIVE

To explore the out-of-set association rules of lung cancer symptoms and drugs through text mining of traditional Chinese medicine (TCM) treatment of lung cancer, and form medical case analysis to analyze the experience of TCM syndrome differentiation in its treatment.

METHODS

The medical records of all patients diagnosed with lung cancer in Nanjing Chest Hospital from January to December 2018 were collected, and the out-of-set association analysis was performed using the MedCase v5.2 TCM clinical scientific research auxiliary platform based on the frequent pattern growth enhanced association analysis algorithm.

RESULTS

In terms of TCM treatment of lung cancer, the clinical symptoms with high correlation included cough, expectoration, chest distress, and white phlegm; and the drugs with high correlation included Pinellia ternata, licorice root, white Atractylodes rhizome, and Radix Ophiopogonis; with the prescriptions based on Erchen and Maimendong decoctions.

CONCLUSION

This analytical study of the medical cases of TCM treatment for lung cancer was performed using data mining techniques, and the out-of-set association rules between clinical symptoms and drugs were analyzed, including the understanding of lung cancer in TCM. Moreover, the essence of experience in drug use was gathered, providing significant scientific guidance for the clinical treatment of lung cancer.

Squamous–columnar junction of Von Ebner’s glands may be a significant origin of squamous cell carcinomas in the base of the tongue

Objectives

The histological origin of base of the tongue (BOT) carcinomas is still elusive, and most studies have been focusing on the lingual tonsil. In this study, we sought to identify the existence of the squamous–columnar junction (SCJ) in the human Von Ebner’s glandular duct and explored the potential of that in forming squamous cell carcinomas in BOT.

Materials and methods

The specific genomes of BOT carcinoma were acquired and screened out by The Cancer Genome Atlas (TCGA) database analysis. The 4-nitroquinoline-1-oxide (4-NQO)-treated mouse model was used to explore the transformation of SCJ during cancerization. We used immunohistochemistry to confirm the characteristics of SCJ in human Von Ebner’s gland, which were further compared with those in the anus and cervix.

Results

The SCJ in the human Von Ebner’s glandular duct was found to be similar to that of the cervix and anus. The transformation zone in the 4-NQO-treated mouse model had a multilayered epithelium structure similar to that of HPV16-transgenic mice. In human, the transformation zone of Von Ebner’s gland is also similar to that of the cervix and anus.

Conclusion

It is the first time that the existence of SCJ in the opening of the human Von Ebner’s glandular duct was confirmed. The SCJ of Von Ebner’s glands may be a significant origin of squamous cell carcinomas in BOT.

Poly-Lactide-Co-Glycolide-Polyethylene Glycol-Ginsenoside Rg3-Ag Exerts a Radio-Sensitization Effect in Non-Small Cell Lung Cancer

Radiotherapy is an effective anti-cancer therapy for patients with non-small cell lung cancer (NSCLC), however, the prognosis is unsatisfactory owing to radio-resistance and toxicity. It is crucial to improve radiotherapy efficacy. Ag nanoparticles (NPs) and ginsenoside Rg3 (Rg3) exerted antitumor and radio-sensitization effects. Therefore, we investigated whether poly-lactide-co-glycolide-polyethylene glycol (PLGA-PEG)-Rg3-Ag will function as a noninvasive, tracing, radiotherapy sensitizer. The morphology of NPs was visualized with transmission electron microscopy (TEM). The drug loading content, encapsulation efficiency, and cumulative drug release of Rg3 was determined by HPLC. Cellular uptake of NPs in A549 and SPCA-1 was measured by immunostaining. The radio-sensitization effect of PLGA-PEG-Rg3-Ag in vitro was determined in A549 by detecting proliferation, colony formation, and apoptosis with CCK-8, clonogenic survival assay, and flow cytometry, while in vivo was determined in nude mice by testing the body weight and tumor volume. PLGA-PEG-Rg3-Ag exerted radio-sensitization effect by reducing cell proliferation and colony formation while enhancing cell apoptosis in A549; reduced tumor volume in nude mice. PLGA-PEG-Rg3-Ag exhibits radio-sensitization effects in NSCLC.

VEGF gene transfection restores the angiogenesis of oral submucous fibrosis in mice

Background

To explore the effectiveness of adenovirus-enhanced green fluorescent protein-vascular endothelial growth factor165 (AD-EGFP-VEGF165) transfection on fibroblasts from mice, and we assessed whether VEGF165 restores the angiogenesis of oral submucous fibrosis (OSF) in mice.

Methods

AD-EGFP-VEGF165 and AD-EGFP were transfected into fibroblasts from mouse buccal tissues in vitro. The expression of VEGF before and after transfection was detected by RT-qPCR and ELISA in each group of fibroblasts. Fifteen OSF mice (pre-experimental construction) were randomly divided into 3 groups, and equal amounts of AD-EGFP-VEGF165 virus, AD-EGFP virus, and saline were injected into the buccal submucosal tissue of OSF mice. The expression of VEGF and local tissue angiogenesis were observed and measured in each group of animals.

Results

The Ad-EGFP-VEGF165-transfected fibroblasts increased human and mouse VEGF expression compared to the Ad-EGFP group and control group (P<0.05). The buccal submucosal tissue of mice was injected with Ad-EGFP-VEGF165 after the 6th day, and the expression of VEGF was effectively expressed in AD-EGFP-VEGF165 group (P<0.05), while no positive expression observed in other groups. and the number of microvessels in the AD-EGFP-VEGF165 group increased significantly compared to the other groups (P<0.05).

Conclusions

Ad-EGFP-VEGF165 can be successfully transfected into fibroblasts from mice, and restored the angiogenesis of OSF in mice.

The preliminary experience of methylene blue assisted laparoscopy in the treatment of renal parapelvic cysts

Renal cyst is a common disease in humans and laparoscopic renal cyst decortication is the gold standard for treatment. However, specialized surgical skills are required for the treatment of renal parapelvic cysts. In this study, we describe an improved laparoscopic method for the treatment of renal parapelvic cysts involving the use of continuous infusion of methylene blue. Sixteen patients with renal parapelvic cyst were enrolled in this study. All patients underwent retrograde ureteral catheterization, with continuous perfusion of the renal pelvis using a solution of 0.2% methylene blue and saline, during laparoscopic decortication of the parapelvic cyst. In one patient, the cyst communicated with the renal collection system which was injured, but this was immediately repaired intraoperatively. All operations were successful, and none was converted to open surgery. There were no occurrences of persistent urinary fistula, bleeding, or other complications postoperatively. All patients were followed-up for 3-24 months, and results of postoperative imaging investigations revealed that all of our patients experienced either complete recovery or a greater than 50% decrease in size of the cysts. Our study demonstrates that methylene blue-assisted laparoscopic treatment is a safe, effective and practical method for the treatment of renal parapelvic cysts.

Monitoring of lung malignant epithelial cells by gene methylation analysis in the conditionally reprogrammed cell cultures

Conditionally reprogrammed cell (CRC) technology is an effective method for culturing primary malignant cells and non-malignant epithelial cells in vitro. This can be useful for precision medicine applications, such as drug sensitivity assays. However, this approach is commonly hindered by the non-specific growth of non-malignant epithelial cells in CRC cultures and the lack of effective biomarkers/assays to distinguish them from primary tumor cells. In this study, we developed a DNA methylation-based, real-time PCR assay to investigate SHOX2 and PTGER4 gene promoters as sensitive markers for human lung cancer. We first found that in formalin-fixed, paraffin-embedded (FFPE) malignant lung samples, 90% (28/31) had increased SHOX2 and/or PTGER4 promoter methylation as compared with their adjacent non-malignant samples. We then applied this assay to fresh surgical tumors and found increased SHOX2 and/or PTGER4 promoter methylation in 80% (20/25) of tumor samples as compared with their corresponding adjacent non-malignant tissues. Increased methylation of SHOX2 or PTGER4 promoter regions was also detected in 52% (13/25) of CRC cultures. The presence of malignant cells was confirmed by growth in soft agar cultures, a hallmark of malignant transformation, as well by EGFR mutation analysis. These results demonstrate that SHOX2 and PTGER4 promoter methylation levels can be used to detect malignant lung epithelial cells in CRC cultures.

Development of a mouse model of arecoline-induced oral mucosal fibrosis

OBJECTIVE

To develop a BALB/c mouse model of oral submucous fibrosis (OSF) induced by arecoline and to exhibit an accumulation of collagen and angiogenesis changes.

METHODS

BALB/c mice were randomly assigned to either the control (distilled water) or experimental group (arecoline) (n = 40). Eight mice from each group were sacrificed every 4 weeks since 8 weeks post treatment. Changes in histopathologic features, levels of collagen type I and collagen type III, and angiogenesis were measured.

RESULTS

In the 8th week, epithelium atrophy, collagen cumulation and micrangium pathologic changes in the lamina propria were observed in the oral mucosa. In the 20th week, hyaline degeneration of the connective tissues was observed on the tongue and palate mucosa. The angiogenesis and collagen type I changed significantly as the diseases advanced (P < 0.05); however, collagen type III was not statistically different.

CONCLUSIONS

An OSF model involving mice can be rapidly induced by drinking a high-dose of arecoline. OSF angiogenic changes in mice primarily decrease and collagen accumulation is mainly collagen type I.

[Application of long term video electroencephalogram and resting-state functional magnetic resonance imaging in detection of cognition in patients with benign epilepsy of childhood with centrotemporal spikes]

Objective: To study the relationship between the changes of brain network and cognition in patients with benign epilepsy of childhood with centrotemporal spikes (BECTS) by using long term video electroencephalogram (VEEG) and resting-state functional magnetic resonance imaging (RS-fMRI) technology. Methods: Eleven patients with right-handed were recruited (from April 2015 to September 2016) from epilepsy specialist outpatients and functional department of neurosurgery of Tianjin Medical University General Hospital. They all underwent the long term VEEG monitoring (one sleep cycle was included at least). According to the spike-wave index (SWI) during slow ware sleep, they were divided into two groups: SWI<50% (5 cases) and SWI≥50% (6 cases). All the patients were assessed with cognitional test including language, execution, memory and attention. They also underwent the head MRI, RS-fMRI examinations. Then the results were comparatively analysed. Results: (1)There were no statisticaly significance in sex, age, age of onset, disease course, total number of seizures, years of education (P>0.05). The Full Intelligence Quotient (FIQ) (87±18), Verbal Intelligence Quotient (VIQ) (88±15) and Performance Intelligence Quotient (PIQ) (89±20) of SWI≥50% group were lower than SWI<50% group(118±8, 114±11, 119±5) and the differences were statistically significant(P<0.05). (2)There was a negative correlation between the FIQ (P=0.002), VIQ (P=0.006), PIQ (P=0.001) and SWI. The FIQ, VIQ and PIQ had no correlation with the sex, age, age of onset, disease course, total number of seizures, years of education (P>0.05). (3)Compared with SWI<50% group, SWI≥50% group showed increased regional homogeneity (ReHo) in the bilateral precentral gyrus, premotor area and the subcortical structure, the right temporal lobe and the bilateral insular lobe(P<0.05); while they showed decreased ReHo in the posterior cingulate gyrus, right posterior inferior temporal lobe and right occipital lobe(P<0.05). Conclusion: The change of the brain network which is caused by the paradoxical and constant discharge during slow ware sleep in patients with BECTS may affect the development of cognition.

Development of coding single nucleotide polymorphic markers in the pearl oyster Pinctada fucata based on next-generation sequencing and high-resolution melting analysis

The pearl oyster Pinctada fucata is an important commercial marine shellfish that is cultured for producing saltwater pearls. In this study, 468 single nucleotide polymorphisms (SNPs) were screened from P. fucata transcriptome data, and 119 polymorphic SNPs were successfully isolated by a two-step small-amplicon high-resolution melting assay. Of these, 88 were annotated with BLAST in the Nr database and 90 were in the open reading frame, including 16 non-synonymous SNPs and 74 synonymous SNPs; 12 SNPs were in the 3'-untranslated region (UTR) and 1 was in the 5'-UTR. Twenty-five SNPs were randomly chosen to test the genetic diversity of 40 wild individuals from Liusha Bay, China. All of the loci had two alleles. The observed and expected heterozygosities ranged from 0.0417 to 0.6042 and from 0.2945 to 0.5053, respectively. Minor allele frequencies ranged from 0.1771 to 0.5000, and the polymorphism information content ranged from 0.2516 to 0.3750. These novel SNP markers can contribute to P. fucata genetics and breeding studies.

Identification of 15 novel polymorphic microsatellite loci in pearl oyster (Pinctada fucata)

The pearl oyster Pinctada fucata is a commercially important marine shellfish. As a result, genetic improvement and selective-breeding program have been conducted for this species. Polymorphic microsatellites are effective molecular markers to investigate molecular marker-assisted selection and genetic variance. In this study, microsatellite DNAs were screened and characterized based on the partial genome sequence of P. fucata. We identified 111 microsatellite DNA motifs through mining the published draft genome sequence of P. fucata. Forty-two loci were screened with 8 P. fucata individuals, and 15 were found to be polymorphic and were therefore further evaluated using 40 wild individuals from the Daya Bay, Shenzhen City, Guangdong Province, China. The number of alleles per locus ranged from 3 to 8, with an average of 5.2667 for the 15 polymorphic loci. Observed and expected heterozygosities ranged from 0.1154 to 0.6216 (0.3321 on average) and 0.4950 to 0.8491 (0.6768 on average), respectively. Of the 15 polymorphic loci, 12 loci deviated from Hardy-Weinberg equilibrium after Bonferroni correction (P < 0.0033). Polymorphism information content ranged from 0.44 to 0.83 with a mean value of 0.63. The results suggest that the markers isolated in this study can be used for research on molecular marker-assisted selection and genetic variance of P. fucata.

Fyn is a redox sensor involved in solar ultraviolet light-induced signal transduction in skin carcinogenesis

Solar ultraviolet (UV) light is a major etiological factor in skin carcinogenesis, with solar UV-stimulated signal transduction inducing pathological changes and skin damage. The primary sensor of solar UV-induced cellular signaling has not been identified. We use an experimental system of solar simulated light (SSL) to mimic solar UV and we demonstrate that Fyn is a primary redox sensor involved in SSL-induced signal transduction. Reactive oxygen species (ROS) generated by SSL exposure directly oxidize Cys488 of Fyn, resulting in increased Fyn kinase activity. Fyn oxidation was increased in mouse skin after SSL exposure, and Fyn knockout (Fyn^−/−) mice formed larger and more tumors compared to Fyn wildtype mice when exposed to SSL for an extended period of time. Murine embryonic fibroblasts (MEFs) lacking Fyn as well as cells in which Fyn expression was knocked down were resistant to SSL-induced apoptosis. Furthermore, cells expressing mutant Fyn (C448A) were resistant to SSL-induced apoptosis. These findings suggest that Fyn acts as a regulatory nexus between solar UV, ROS and signal transduction during skin carcinogenesis.

Morphological analysis and muscle-associated gene expression during different muscle growth phases of Megalobrama amblycephala

Skeletal muscle growth is regulated by both positive and negative factors, such as myogenic regulatory factors (MRFs) and myostatin (MSTN), and involves both hyperplasia and hypertrophy. In the present study, morphological changes during muscle development in Megalobrama amblycephala were characterized and gene expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) analysis in juvenile [60, 90, 120, and 180 days post-hatching (dph)] and adult fish. Our results show that during muscle development, the frequency of muscle fibers with a diameter <20 μm dramatically decreased in both red and white muscles, with a concomitant increase in the frequency of >30 μm fibers in red muscle and >50 μm fibers in white muscle. At 90-120 dph, the ratio of hyperplastic to hypertrophic areas in red and white muscles increased, but later decreased at 120-180 dph. The effect of hypertrophy was significantly larger than hyperplasia during these phases. qRT-PCR indicated MRF and MSTN (MSTNa and MSTNb) genes had similar expression patterns that peaked at 120 dph, with the exception of MSTNa. This new information on the molecular regulation of muscle growth and rapid growth phases will be of value to the cultivation of M. amblycephala.

Co-expression of march5b and tlr7 in large yellow croaker Larimichthys crocea in response to Cryptocaryon irritans infection

In this study, molecular characteristics of march5b and co-expression of march5b and tlr7 in response to the infection of Cryptocaryon irritans in the large yellow croaker Larimichthys crocea were investigated. The full-length complementary (c)DNA of march5b was 1314 bp, including an open reading frame of 846 bp encoding a polypeptide of 281 amino acids, and the full-length genomic sequence was composed of 23,577 nucleotides, including six exons and five introns. The putative March5b protein contained a RINGv motif and four transmembrane domains. The march5b transcripts were broadly distributed in all detected tissues, with a strong expression in blood, brain and gills, and a weak expression in kidney by quantitative PCR analysis. The expression of march5b and tlr7 in the skin, gills, spleen and head kidney changed in the same manner at most time points post-primary infection with C. irritans. Significant increase was observed in the skin with march5b at days 2 and 3 by 26.10 and 6.88 fold, respectively, and with tlr7 at day 3 by 57.68 fold, when compared with the control. Their expressions, however, were decreased in the gills, especially at day 3 (march5b by 8.9%, tlr7 by 22.06%). In the spleen and head kidney, march5b and tlr7 transcripts were up-regulated early, then noticeably declined at day 3. These results suggested that march5b and tlr7 are co-expressed in response to parasite infection and March5b probably catalyses ubiquitination of some proteins of TLR7 signalling pathway.

Genome-wide DNA methylation and gene expression patterns provide insight into polycystic ovary syndrome development

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. However, the epigenetic mechanism involved in PCOS progression remains largely unknown. Here, combining the DNA methylation profiling together with transcriptome analysis, we showed that (i) there were 7929 differentially methylated CpG sites (β > 0.1, P < 0.05) and 650 differential transcripts (fold change > 1.5, P < 0.005) in PCOS compared to normal ovaries; (ii) 54 genes were identified with methylated levels that were correlated with gene transcription in PCOS; and (iii) there were less hypermethylated sites, but many more hypomethylated sites residing in CpG islands and N_Shore in PCOS. Among these genes, we identified that several significant pathways, including the type I diabetes mellitus pathway, p53 signaling pathway and NOD-like receptor signaling pathway, and some immune and inflammatory diseases may be highly involved in PCOS development. These results suggested that differences in genome-wide DNA methylation and expression patterns exist between PCOS ovaries and normal ovaries; epigenetic mechanisms may in part be responsible for the different gene expression and PCOS phenotype. All of this may improve our understanding of the basic molecular mechanism underlying the development of PCOS.

CDC42 inhibition suppresses progression of incipient intestinal tumors

Mutations in the APC or β-catenin genes are well-established initiators of colorectal cancer, yet modifiers that facilitate the survival and progression of nascent tumor cells are not well defined. Using genetic and pharmacologic approaches in mouse colorectal cancer and human colorectal cancer xenograft models, we show that incipient intestinal tumor cells activate CDC42, an APC-interacting small GTPase, as a crucial step in malignant progression. In the mouse, Cdc42 ablation attenuated the tumorigenicity of mutant intestinal cells carrying single APC or β-catenin mutations. Similarly, human colorectal cancer with relatively higher levels of CDC42 activity was particularly sensitive to CDC42 blockade. Mechanistic studies suggested that Cdc42 may be activated at different levels, including at the level of transcriptional activation of the stem cell-enriched Rho family exchange factor Arhgef4. Our results indicate that early-stage mutant intestinal epithelial cells must recruit the pleiotropic functions of Cdc42 for malignant progression, suggesting its relevance as a biomarker and therapeutic target for selective colorectal cancer intervention.

Targeted p16(Ink4a) epimutation causes tumorigenesis and reduces survival in mice

Cancer has long been viewed as a genetic disease; however, epigenetic silencing as the result of aberrant promoter DNA methylation is frequently associated with cancer development, suggesting an epigenetic component to the disease. Nonetheless, it has remained unclear whether an epimutation (an aberrant change in epigenetic regulation) can induce tumorigenesis. Here, we exploited a functionally validated cis-acting regulatory element and devised a strategy to induce developmentally regulated genomic targeting of DNA methylation. We used this system to target DNA methylation within the p16(Ink4a) promoter in mice in vivo. Engineered p16(Ink4a) promoter hypermethylation led to transcriptional suppression in somatic tissues during aging and increased the incidence of spontaneous cancers in these mice. Further, mice carrying a germline p16(Ink4a) mutation in one allele and a somatic epimutation in the other had accelerated tumor onset and substantially shortened tumor-free survival. Taken together, these results provide direct functional evidence that p16(Ink4a) epimutation drives tumor formation and malignant progression and validate a targeted methylation approach to epigenetic engineering.

The effect of total cholesterol on myocardial infarction in Chinese male hypertension population

OBJECTIVE

Total cholesterol (TC) is an important risk factor for myocardial infarction (MI), but the effect of TC on MI in Chinese male hypertension population has not been well documented. We conducted a prospective cohort study to determine the incidence and relative risk for MI across a wide range of TC levels in Chinese male hypertension population.

METHODS

A cohort of 5298 male employees aged 18-74 years recruited from Capital Steel and Iron Company in Beijing of China in 1974-1980 was followed up for an average of 20.84 years. A total of 122 incident MI cases were identified during the period of follow-up.

RESULTS

The incidence of MI among participants with elevated TC and those with desirable TC in male non-hypertension population was 137.20 and 63.81 per 100,000 person-years, respectively; and the corresponding incidence in male hypertension population was 279.80 and 130.96 per 100,000 person-years, respectively. After adjustment for important covariables, 10.38%, 16.71%, and 23.80% of MI cases were attributable to hypertension, elevated TC, and hypertension plus elevated TC, respectively. In male hypertension population, the multivariate adjusted hazard ratios of MI were 1.21, 2.39, 3.38, and 3.95 for participants with TC level of 5.17-5.68, 5.69-6.20, 6.21-6.71, and > or = 6.72 mmol/L, compared with those with TC < 5.17 mmol/L. The corresponding population attributable risks were 2.92%, 9.20%, 8.87%, and 9.84%, respectively.

CONCLUSION

Elevated TC is an important independent risk factor of MI both in male non-hypertension and hypertension populations. There is a linear association between TC level and MI incidence in Chinese male hypertension population.

Perilipin gene 1237 T > C polymorphism is not associated with obesity risk in northern Chinese Han adults

OBJECTIVE

To identify the association between PLIN 1237 polymorphism and obesity in Chinese Han adults.

METHODS

A total of 994 adults (157 obese subjects, 322 overweight subjects, and 515 normal controls) were recruited from two rural communities. PLIN 1237 polymorphism was genotyped by polymerase chain reaction-restriction-fragment-length-polymorphism (PCR-RFLP). Association between PLIN polymorphisms and obesity status was estimated by ordinal logistic regression.

RESULTS

The three genotypes of PLIN 1237 were detected with a percentage of 54.3%, 37.1%, and 8.6% in TT, TC, and CC genotypes, respectively. For the PLIN 1237 polymorphism locus, the frequency of alleles T and C was 0.73 and 0.27, respectively. The PLIN 1237 polymorphisms were in Hardy-Weinberg equilibrium. PLIN 1237 polymorphism was not associated with obesity. The odds ratio for overweight or obesity for the CC+TC genotype was 0.8 (0.4, 1.4) in women (P = 0.4) and 0.6 (0.3, 1.3) in men (P = 0.2) after adjustment for age, education, household income and alcohol consumption, smoking, and physical activity.

CONCLUSION

Chinese Han adults have a lower frequency of variant-allele C in PLIN 1237. PLIN 1237 T > C polymorphism is not significantly associated with obesity in northern Chinese adults.

A combined DNA vaccine provides protective immunity against Mycobacterium bovis and Brucella abortus in cattle

We evaluated the immunogenicity and protective efficacy of a combined DNA vaccine containing six genes encoding immunodominant antigens from Mycobacterium bovis and Brucella abortus. The number of lymph node and spleen cultures positive for M. bovis and B. abortus from calves immunized with the combined DNA vaccine was significantly reduced (p < 0.01) compared with unvaccinated calves after challenge with virulent M. bovis and B. abortus 544. The combined DNA vaccine group displayed stronger antigen-specific interferon-gamma (IFN-gamma) responses and antigen-specific IFN-gamma ELISPOT activities 2 months after final immunization and after challenge. Antigen-specific CD4(+) and CD8(+) T cell responses in the combined DNA vaccine group were higher than either the Bacillus Calmette-Guerin (BCG)-positive or S19-positive control group. Likewise, more calves in the DNA vaccine group exhibited antigen-specific IgG titers and had higher IgG titers than those in the BCG- or S19-immunized groups 2 months after the final immunization. Moreover, two antigens in the combined DNA vaccine induced significant antigen-specific IFN-gamma responses 6 months after challenge (p < 0.05). Bacterial counts and pathological analyses of the challenged animals indicated that the combined DNA vaccine provided significantly better protection than the BCG vaccine against M. bovis, and the protection level induced by the combined DNA vaccine was comparable to S19 against B. abortus. This is the first report to demonstrate that a single combined DNA vaccine protects cattle against two infectious diseases.

[Expression and significance of basic fibroblast growth factor in infant vascular anomalies]

PURPOSE

To investigate the expression of basic fibroblast growth factor (bFGF) in infant's peripheral blood and tumor blood of vascular malformation and peripheral venous blood of hemangioma, and the possibility to differentiate hemangioma from vascular malformations by detecting bFGF level in peripheral blood.

METHODS

The level of bFGF in peripheral blood(49 vascular malformations ,32 hemangioma cases and 23 normal cases) and tumor blood(14 venous malformations) of infants was measured by ELISA.SPSS11.5 software package was used to analyze the data and student's t test and ANOVA were used to determine the difference between different groups.

RESULTS

The expression of bFGF in tumor blood from infants with venous malformations was significantly higher than that in peripheral blood (P<0.05); No significant difference of bFGF level in peripheral blood was found between hemangioma,vascular malformation and normal infants(P>0.05).

CONCLUSIONS

The level of bFGF in tumor blood of from infants with venous malformation was higher than that in peripheral blood; Examination of bFGF in peripheral blood can not differentiate hemangioma from vascular malformations.

Structure of supramolecular assemblies formed by alpha,delta-tetramethylcucurbit[6]uril and 4-nitrophenol

A host-guest assembly, [(C(40)H(44)N(24)O(12)).(C(6)H(5)NO(3))(8).13(H(2)O)] (1), based on a partial substituted cucurbituril, alpha,delta-tetramethylcucurbit[6]uril (TMeQ[6]), and 4-nitrophenol was synthesized and structurally characterized by single-crystal X-ray diffraction. A combination of hydrogen-bonding between the latticed water molecule and the hydroxyl group of 4-nitrophenol, the hydroxyl group of 4-nitrophenol and the carbonyl groups lining the portals in additon, the C-H...pi interactions between the 4-nitrophenol molecules could be the driving forces of formation such an exclusion host-guest assembly.

Direct comparison of optical frequency combs using a comb-injection-lock technique

This paper demonstrates a direct comparison of optical frequency combs (OFCs) with different repetition rates without a stable intermediate laser using a single-mode comb-injection-lock technique. Two OFCs based on Ti:Sapphire mode-locked lasers were compared utilizing a single-mode diode laser for the selection and the amplification of one mode of an OFC by comb-injection, which makes the direct comb comparison possible. The frequencies of the two combs were found to agree within 0.019 Hz at 352 THz with the uncertainty of 0.25 Hz (7.1 x 10(-16) ). This is one of the best results among the comparisons of combs referenced to a microwave frequency. This technique simplifies the comb comparison utilities and can be applied even when repetition rates differ.

Polo-like kinase 1 may regulate G2/M transition of mouse fertilized eggs by means of inhibiting the phosphorylation of Tyr 15 of Cdc2

Polo-like kinase 1(Plk1) has been reported to be a multifunctional kinase that plays pivotal regulatory roles in microtubule assembly during mammalian early embryonic mitosis. In the present study, we examined the expression of Plk1 at protein and mRNA level in mouse fertilized eggs by Western blot and RT-PCR. We also examined the kinase activity of Plk1. At various developmental phases of mouse one-cell stage embryos, both the protein and the mRNA of Plk1 were uniformly distributed; but the kinase activity of Plk1 increased at G2/M phase and decreased at the end of M phase. At the meantime, the phosphorylation of Tyr 15 of Cdc2 was inhibited at M phase. To investigate its function in mammalian fertilized eggs further, we used specific short hairpin RNAs (shRNA) and scytonemin, the putative inhibitor of Plk1 to suppress the activity of Plk1 in mouse fertilized eggs. Upon blockage of the activation of with Plk1 shRNA and scytonemin in mouse one-cell stage embryos, the cleavage rate decreased and the phosphorylation level of Tyr 15 of Cdc2 increased. These results imply that the Plk1 may regulate cell cycle progression of mouse fertilized eggs by means of inhibiting the phosphorylation of Tyr 15 of Cdc2.

A combined DNA vaccine enhances protective immunity against Mycobacterium tuberculosis and Brucella abortus in the presence of an IL-12 expression vector

We examined the immunogenicity and protective efficacy of a combined DNA vaccine that included six genes encoding immunodominant antigens from Mycobacterium tuberculosis and Brucella abortus. The IL-12 adjuvant system was used for immunization in combination with the combined DNA vaccine (DNA-IL-12(+)). Mice immunized with DNA-IL-12(+) had significantly reduced CFU counts for M. tuberculosis and B. abortus in lung and spleen, respectively (P<0.001), and DNA-IL-12(+) elicited better protection than the combined DNA vaccine alone (DNA-IL-12(-)) or with the positive control groups after challenge with a virulent M. tuberculosis strain and B. abortus 2308 infection. The DNA-IL-12(+) group had stronger antigen-specific IFN-gamma ELISPOT activities and higher levels of antigen-specific CD4(+) and CD8(+) T cell responses than either the DNA-IL-12(-) or positive control groups. Likewise, antigen-specific IgG titers were also much higher than in other immunized groups. Moreover, DNA-IL-12(+) gave a stronger IgG2a-skewed response than did DNA-IL-12(-). In addition, its mean concentrations of IFN-gamma and IL-2 were about 2.5- to 4.5-fold higher than those observed in the DNA-IL-12(-)-treated mice, and were significantly higher than control groups (P<0.01 or P<0.001), whereas IL-4 and IL-10 secretion were lower. These results suggest that IL-12 acts as an adjuvant to enhance protective immunity against M. tuberculosis and B. abortus through the induction of stronger Th1-associated immune responses. This is the first report to show that a single combined DNA vaccine protects animals against two infectious diseases.

A Combined DNA Vaccine Encoding BCSP31, SOD, and L7/L12 Confers High Protection Against Brucella abortus 2308 by Inducing Specific CTL Responses

We constructed a combined DNA vaccine comprising genes encoding the antigens BCSP31, superoxide dismutase (SOD), and L7/L12 and evaluated its immunogenicity and protective efficacy. Immunization of mice with the combined DNA vaccine offered high protection against Brucella abortus (B. abortus) infection. The vaccine induced a vigorous specific immunoglobulin G (IgG) response, with higher IgG2a than IgG1 titers. Cytokine profiling performed at the same time showed a biased Th1-type immune response with significantly increased interferon-gamma and tumor necrosis factor-alpha stimulation. CD8(+), but not CD4(+), T cells accumulated at significantly higher levels after administration of the vaccine. Granzyme B-producing CD8(+) T cells were significantly higher in number in samples prepared from combined DNA-vaccinated mice compared with S19-vaccinated mice, demonstrating that the cytotoxicity lysis pathway is involved in the response to Brucella infection. The success of our combined DNA vaccine in a mouse model suggests its potential efficacy against brucellosis infection in large animals.

A combined DNA vaccine-prime, BCG-boost strategy results in better protection against Mycobacterium bovis challenge

In this study, we demonstrated that calves vaccinated with a combined DNA vaccine encoding Ag85B, MPT- 64, and MPT-83 antigens from the Mycobacterium tuberculosis for the priming and subsequently boosting with BCG prior to experimental challenge with virulent Mycobacterium bovis (M. bovis) resulted in improved immune responses over immunizing. Vaccination with the combined DNA/BCG induced higher levels of antigen- specific gamma interferon (IFN-gamma) in whole-blood cultures 4 weeks after final vaccination and the level of antigen-specific IFN-gamma in response to Ag85, MPT-64, and MPT-83 were still higher 4 weeks after challenge when compared to the combined DNA group. There was a significant bias toward induction of CD4+ T cells rather than CD8+ T cells responses, and the mean percentage of CD4+ T cells was increased about 2.6-fold in peripheral blood mononuclear cells (PBMC) cultures in DNA prime-BCG boost vaccination when compared to the nonvaccinated group. In addition, DNA prime-BCG boost vaccination resulted in stronger humoral immune responses, and the levels of the specific antibodies to three antigens were increased two- to 32- fold when compared to the combined DNA group. Vaccination with the combined DNA/BCG induced a high level of protection against an intratracheal challenge with virulent M. bovis, based on a significant enhancement of six pathological and microbiological parameters of protection compared to the nonvaccinated group. Finally, the combined DNA/BCG increased the protective efficacy by more than 10-100-fold as measured by reduced CFU counts in the lungs from calves challenged with M. bovis compared to the combined DNA and BCG groups. These results suggest that use of the prime-boost strategy offers better protection against bovine tuberculosis than does the combined DNA vaccines and BCG.

Expression and immunohistochemical localization of Cdc2 and P70S6K in different stages of mouse germ cells

In order to determine the function and possible relationship between Cdc2 and P(70)S6K, Western blot analysis and immunohistochemistry analysis were used to study the expression and kinase activity of Cdc2 and P(70)S6K in male mouse germ cells. With the maturation of germ cells in the testis, the expression of Cdc2 and P(70)S6K was relatively constant. However, the kinase activity of P(70)S6K was increased and the phosphorylation of Tyr15 residue of Cdc2 was enhanced, which suggests that the kinase activity of Cdc2 is decreasing. Immunohistochemistry analysis also showed that there was a P(70)S6K transfer from nucleus to cytoplasm during spermatogenesis. During spermatogenesis, cell division of the germ cell in male mouse is decelerated; nevertheless, cell growth is enhanced. Cdc2 and P(70)S6K are involved in these two processes. It could be an alternative mechanism to prepare for future fertilization that Cdc2 is able to maintain a subtle balance between the production and growth of male germ cells by regulating P(70)S6K.

Coadministration of Interleukin 2 Plasmid DNA with Combined DNA Vaccines Significantly Enhances the Protective Efficacy AgainstMycobacterium tuberculosis

Coadministration of interleukin 2(IL-2) plasmid DNA with combined DNA vaccines enhanced Th1-type cellular responses by producing higher amounts of IFN-gamma with a higher ratio of antigen-specific IgG2a/IgG1. The IFN-gamma specific for Ag85B, MPT64, and MPT83 in this group was 415, 267, and 255 U/ml, respectively, and was 1.6-, 1.8-, and 2.5-fold higher than that of the same vaccine without adding IL-2. The IgG2a/IgG1 ratio for Ag85B, MPT64, and MPT83 was 4, 8, and 4, respectively, upon addition of the genetic adjuvant in the DNA vaccine, which was four times higher for every antigen when IL-2 was not included. Fluorescence activated cell sorter (FACS) analysis showed that, in the presence of IL-2, CD8+ and CD4+ T cells increased significantly, whereas in the absence of the genetic adjuvant, only a mild increase was observed for CD8+ T cells compared to the vector DNA-treated group. Bacterial CFU was reduced to less than 1/100 in the lung and to about 1/10 in the spleen relative to the same combined DNA vaccine without IL-2. The lungs of this group of mice showed much less damage due to an influx of epithelioid macrophages and less lymphocytes. RT-PCR showed that antigen genes could be detected in more organs and for a longer period of time when treated with combined DNA vaccine formulated in IL-2. We suggest that IL-2 enhanced the immunigencity and protective efficacy in immunized mice by improving the Th1-type response and also by prolonging the antigen gene expression in different organs.

Diffuse cavernous hemangioma of the rectosigmoid colon

Diffuse cavernous hemangioma of the rectosigmoid colon is an uncommon benign vascular lesion. We report 5 cases of diffuse cavernous hemangioma, focusing on the clinical features, diagnosis procedure and treatment. Five patients have undergone sphincter-saving procedures, 3 cases had coloanal sleeve anastomoses and 1 patient each had pull-through anastomosis and lower anterior resection. During the follow-up, which ranged from 3 to 10 years, 3 patients had no further anal bleeding and 2 patients had minor intermittent anal bleeding. Continence for normal stool was satisfactory in all patients. In conclusion, sphincter-saving procedure is most appropriate and curative approach for the treatment of diffuse cavernous hemangioma. Imaging study plays an important role in the diagnosis, preoperative staging and follow-up.

Combined DNA vaccine encapsulated in microspheres enhanced protection efficacy against Mycobacterium tuberculosis infection of mice

In a study to develop novel vaccination strategies against tuberculosis, we encapsulated DNA encoding Ag85B, MPT-64 and MPT-83 antigens mixed with dimethyldioctyldecyl ammonium bromide (DDA) into biodegradable poly(dl-lactide-co-glycolide, PLGA) microspheres. Scanning electron microscopy (SEM) analysis demonstrated a uniform microsphere population with a mean diameter of <5microm. Using RT-PCR we were able to demonstrate antigen gene expression in selected tissue. Moreover, in mice injected with PLGA encapsulated DNA, the levels of expression appeared to be higher comparing to those injected with non-encapsulated DNA. Also, C57BL/6 mice immunized with a single dose of PLGA encapsulated DNA produced increased levels of IFN-gamma in the supernatant of spleen cells when cultured in the presence of the recombinant antigens. High levels of specific IgG antibody against the three antigens were also observed. In vaccine/challenge experiments, mice receiving a single dose of PLGA encapsulated DNA were protected against Mycobacterium tuberculosis challenge at levels comparable to groups of mice immunized with three doses of non-encapsulated DNA vaccine or with Mycobacterium bovis BCG.

Combined DNA vaccines formulated either in DDA or in saline protect cattle from Mycobacterium bovis infection

We tested the effectiveness of combined DNA vaccines encoding antigens Ag85B, MPT64 and MPT83 from Mycobacterium tuberculosis on cattle. Our results showed that calves treated with combined DNA vaccines in the presence of dimethyldioctyldecyl ammonium bromide (DDA) or saline elicited a strong gamma interferon (IFN-gamma) response 1 or 2 months after the third vaccination. All three antigens induced substantial levels of IFN-gamma production 1 month after the bacterial challenge, when the BCG-driven IFN-gamma levels dropped to less than one third of their peak values. Animals receiving combined DNA vaccines produced highest amounts of IgG antibody titer 2 months after the third vaccination. Steady state low IgG levels were found 2 months after bacterial challenge. A few small lung and lymph node lesions were detected in 1/5 animals treated with combined DNA vaccines, whereas 3/5 of BCG-treated and 5/5 of vector-control calves showed larger and significantly more lesions. About 70- to 100-fold fewer bacteria were found in the lungs and lymph nodes of combined DNA vaccine-treated animals compared to those of the control group. Histopathological analyses showed that vaccinated calves possessed substantially improved post-infection lung and lymph node pathology relative to the controls. Our data indicate that combined DNA vaccines may be used in cattle to combat bovine tuberculosis.

Electron exchange in dissociative excitation of molecular hydrogen using polarized electrons

The effects of electron exchange and spin orbit interaction in dissociative excitation processes in H2 molecules have been explored using excitation by polarized electrons. Observations of the circular and linear Stokes polarizations of the Balmer-alpha photons determined the alignment and orientation of the excited atomic hydrogen atoms, the excited molecular states, and the dissociative excitation processes via predissociation with short and long range transitions.

Effect of N-glycosylation on ligand binding affinity of rat V1a vasopressin receptor

A rat Vla vasopressin (rVla) receptor has two putative N-glycosylation sites at 14th and 27th amino acid asparagine in the extracellular N-terminus. In the present study, we examined the possible roles of N-glycosylation of the N-terminus in the receptor function. Three point mutants for deglycosylated rVla receptor were generated in which the 14th and/or the 27th asparagine was replaced with glutamine, namely N14Q, N27Q, and N14:27Q, each tagged with an enhanced green fluorescent protein (EGFP) at their C-termini, and transfected to COS-7 or HEK292 cells. The two single mutants and a double mutant have progressively smaller molecular mass compared to the wild-type receptor as determined by immunoblot analysis, indicating that the two sites are effectively glycosylated in vivo. The maximal ligand binding capacities of three mutant receptors were comparable to that of wild-type (17.02 +/- 1.32 pmol/g protein) with modest changes in ligand binding affinities: N27Q and N14:27Q had decreased binding affinities compared to N14Q and wild-type receptors. The reduced binding affinities of the deglycosylated mutants are not likely due to the impaired intracellular transport since their traffickings were indistinguishable from one another. Taken together, these results suggest that the N-glycosylation at the two sites of the N-terminus of rV1a receptor minimally affects the surface expression and trafficking of the receptor.

[Electroporation of sperm to introduce foreign DNA into the genome of Pinctada maxima (Jameson)]

Gene transfer was investigated in marine molluscs via electroporated sperm. Sperm of P. maxima (J.) was incubated with linear "all-fish" growth hormone gene (pCAgcGH and pCAgcGHc) for 30 min. Then, mature eggs were in-vitro fertilized with the sperm cells treated with electroporation at 10 kV and 2(7) pulses of six cycles. DNA was extracted from spat and analyzed by PCR and southern blot. The results indicated that the foreign DNA had been transferred into the genome of experimental molluscs. The transgenetic ration was 5.6%, 20% and 50% when 2 micrograms/mL, 6 micrograms/mL and 18 micrograms/mL of foreign DNA was used, respectively. It is suggested that the transferred efficiency is correlated with the amount of the foreign DNA.

Molecular mechanism for the Shp-2 tyrosine phosphatase function in promoting growth factor stimulation of Erk activity

We have previously shown that activation of extracellular signal-regulated kinase (Erk) by epidermal growth factor (EGF) treatment was significantly decreased in mouse fibroblast cells expressing a mutant Shp-2 molecule lacking 65 amino acids in the SH2-N domain, Shp-2(Delta46-110). To address the molecular mechanism for the positive role of Shp-2 in mediating Erk induction, we evaluated the activation of signaling components upstream of Erk in Shp-2 mutant cells. EGF-stimulated Ras, Raf, and Mek activation was significantly attenuated in Shp-2 mutant cells, suggesting that Shp-2 acts to promote Ras activation or to suppress the down-regulation of activated Ras. Biochemical analyses indicate that upon EGF stimulation, Shp-2 is recruited into a multiprotein complex assembled on the Gab1 docking molecule and that Shp-2 seems to exert its biological function by specifically dephosphorylating an unidentified molecule of 90 kDa in the complex. The mutant Shp-2(Delta46-110) molecule failed to participate in the Gab1-organized complex for dephosphorylation of p90, correlating with a defective activation of the Ras-Raf-Mek-Erk cascade in EGF-treated Shp-2 mutant cells. Evidence is also presented that Shp-2 does not appear to modulate the signal relay from EGF receptor to Ras through the Shc, Grb2, and Sos proteins. These results begin to elucidate the mechanism of Shp-2 function downstream of a receptor tyrosine kinase to promote the activation of the Ras-Erk pathway, with potential therapeutic applications in cancer treatment.

Regulation of neuregulin-mediated acetylcholine receptor synthesis by protein tyrosine phosphatase SHP2

Synapse-specific expression of the nicotinic acetylcholine receptor (AChR) is believed to be mediated by neuregulin, an epidermal growth factor-like trophic factor released by somatic motoneurons at the neuromuscular junction (NMJ). Neuregulin stimulates ErbB2, ErbB3, and ErbB4, members of the ErbB family of receptor tyrosine kinases. SHP2 is a cytoplasmic protein tyrosine phosphatase containing two Src homology 2 domains near its N terminus, and has been shown to be a positive mediator of mitogenic responses to various growth factors. We found that SHP2 interacted with ErbB2 and ErbB3 after neuregulin stimulation of muscle cells. Expression of SHP2 in C2C12 mouse muscle cells attenuated the neuregulin-induced expression of an AChR epsilon-promoter reporter gene, whereas a catalytically inactive SHP2 mutant or a mutant lacking the N-terminal Src homology 2 (SH2) domain enhanced reporter expression, suggesting that SHP2 negatively regulates the neuregulin signaling pathway. In fibroblast cells that express a mutant SHP2 with a targeted deletion of the N-terminal SH2 domain, neuregulin-mediated activation of the Ras/Raf/extracellular signal-regulated kinase cascade was enhanced. Furthermore, we found that SHP2 immunoreactivity colocalized with the staining of alpha-bungarotoxin, a marker of the NMJ. These results demonstrate a negative role of SHP2 in the neuregulin signal that leads to AChR gene expression at the NMJ.

Gab2, a new pleckstrin homology domain-containing adapter protein, acts to uncouple signaling from ERK kinase to Elk-1

We describe a novel human adapter molecule containing a pleckstrin homolgy (PH) domain at the N terminus that is closely related to human Grb2-associated binder 1, Gab1, and Drosophila daughter of sevenless. We designate this protein as Gab2. Northern blot analysis indicates that Gab2 is widely expressed and has an overlapping but distinctive expression pattern as compared with Gab1, with high levels of Gab2 mRNA detected in the heart, brain, placenta, spleen, ovary, peripheral blood leukocytes, and spinal cord. Upon tyrosine phosphorylation, Gab2 physically interacts with Shp2 tyrosine phosphatase and Grb2 adapter protein. Strikingly, Gab2 has an inhibitory effect on the activation of Elk-1-dependent transcription triggered by a dominant active Ras mutant (RasV12) or under growth factor stimulation, whereas Gab1 acts to potentiate slightly the Elk-1 activity in the same system. In contrast to the reciprocal effects of Gab1 and Gab2 in mediating Elk-1 induction, these two molecules have a similar function in extracellular signal-regulated kinase activation induced by either oncogenic Ras or growth factor stimulation. Taken together, these results argue that Gab1 and Gab2, two closely related PH-containing adapter proteins, might have distinct roles in coupling cytoplasmic-nuclear signal transduction. This is the first evidence that an intracellular molecule with a PH domain operates as a negative effector in signal relay to the regulation of gene expression.

Shp-2 tyrosine phosphatase functions as a negative regulator of the interferon-stimulated Jak/STAT pathway

Shp-2 is an SH2 domain-containing protein tyrosine phosphatase. Although the mechanism remains to be defined, substantial experimental data suggest that Shp-2 is primarily a positive regulator in cell growth and development. We present evidence here that Shp-2, while acting to promote mitogenic signals, also functions as a negative effector in interferon (IFN)-induced growth-inhibitory and apoptotic pathways. Treatment of mouse fibroblast cells lacking a functional Shp-2 with IFN-alpha or IFN-gamma resulted in an augmented suppression of cell viability compared to that of wild-type cells. To dissect the molecular mechanism, we examined IFN-induced activation of signal transducers and activators of transcription (STATs) by electrophoretic mobility shift assay, using a specific DNA probe (hSIE). The amounts of STAT proteins bound to hSIE upon IFN-alpha or IFN-gamma stimulation were significantly increased in Shp-2(-/-) cells. Consistently, tyrosine phosphorylation levels of Stat1 upon IFN-gamma treatment and, to a lesser extent, upon IFN-alpha stimulation were markedly elevated in mutant cells. Furthermore, IFN-gamma induced a higher level of caspase 1 expression in Shp-2(-/-) cells than in wild-type cells. Reintroduction of wild-type Shp-2 protein reversed the hypersensitivity of Shp-2(-/-) fibroblasts to the cytotoxic effect of IFN-alpha and IFN-gamma. Excessive activation of STATs by IFNs was also diminished in mutant cells in which Shp-2 had been reintroduced. Together, these results establish that Shp-2 functions as a negative regulator of the Jak/STAT pathway. We propose that Shp-2 acts to promote cell growth and survival through two mechanisms, i.e., the stimulation of growth factor-initiated mitogenic pathways and the suppression of cytotoxic effect elicited by cytokines, such as IFNs.

Protein-tyrosine phosphatase Shp-2 regulates cell spreading, migration, and focal adhesion

Shp-2, a widely expressed cytoplasmic tyrosine phosphatase with two SH2 domains, is believed to participate in signal relay downstream of growth factor receptors. We show here that this phosphatase also plays an important role in the control of cell spreading, migration, and cytoskeletal architecture. Fibroblast cells lacking a functional Shp-2 were impaired in their ability to spread and migrate on fibronectin compared with wild-type cells. Furthermore, Shp-2 mutant cells displayed an increased number of focal adhesions and condensed F-actin aggregation at the cell periphery, properties reminiscent of focal adhesion kinase (FAK)-deficient cells. This is consistent with our previous observations in vivo that mice homozygous for the Shp-2 mutation died at midgestation with similar phenotype to FAK and fibronectin-deficient embryos, having severe defects in mesodermal patterning, particularly the truncation of posterior structures. Biochemical analysis demonstrated that FAK dephosphorylation was significantly reduced in Shp-2 mutant cells in suspension. Furthermore, regulated association of Src SH2 domain with FAK and paxillin during cell attachment and detachment on fibronectin was disrupted in Shp-2 mutant cells. This report defines a unique role of the Shp-2 tyrosine phosphatase in cell motility, which might guide the design of a new strategy for pharmaceutical interference of tumor metastasis.