Identification and characterization of the novel Col10a1 regulatory mechanism during chondrocyte hypertrophic differentiation

The majority of human skeleton develops through the endochondral pathway, in which cartilage-forming chondrocytes proliferate and enlarge into hypertrophic chondrocytes that eventually undergo apoptosis and are replaced by bone. Although at a terminal differentiation stage, hypertrophic chondrocytes have been implicated as the principal engine of bone growth. Abnormal chondrocyte hypertrophy has been seen in many skeletal dysplasia and osteoarthritis. Meanwhile, as a specific marker of hypertrophic chondrocytes, the type X collagen gene (COL10A1) is also critical for endochondral bone formation, as mutation and altered COL10A1 expression are often accompanied by abnormal chondrocyte hypertrophy in many skeletal diseases. However, how the type X collagen gene is regulated during chondrocyte hypertrophy has not been fully elucidated. We have recently demonstrated that Runx2 interaction with a 150-bp mouse Col10a1 cis-enhancer is required but not sufficient for its hypertrophic chondrocyte-specific reporter expression in transgenic mice, suggesting requirement of additional Col10a1 regulators. In this study, we report in silico sequence analysis of this 150-bp enhancer and identification of its multiple binding factors, including AP1, MEF2, NFAT, Runx1 and TBX5. Using this enhancer as bait, we performed yeast one-hybrid assay and identified multiple candidate Col10a1-interacting genes, including cyclooxygenase 1 (Cox-1) and Cox-2. We have also performed mass spectrometry analysis and detected EF1-alpha, Fus, GdF7 and Runx3 as components of the specific complex formed by the cis-enhancer and nuclear extracts from hypertrophic MCT (mouse chondrocytes immortalized with large T antigen) cells that express Col10a1 abundantly. Notably, some of the candidate genes are differentially expressed in hypertrophic MCT cells and have been associated with chondrocyte hypertrophy and Runx2, an indispensible Col10a1 regulator. Intriguingly, we detected high-level Cox-2 expression in hypertrophic MCT cells. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays confirmed the interaction between Cox-2 and Col10a1 cis-enhancer, supporting its role as a candidate Col10a1 regulator. Together, our data support a Cox-2-containing, Runx2-centered Col10a1 regulatory mechanism, during chondrocyte hypertrophic differentiation.

Effect of functional nuclear factor-kappaB genetic polymorphisms on hepatitis B virus persistence and their interactions with viral mutations on the risk of hepatocellular carcinoma

BACKGROUND

Nonresolving inflammation and viral mutations are important in hepatitis B virus (HBV)-induced hepatocarcinogenesis. However, the effects of genetic polymorphisms affecting nuclear factor-kappaB (NF-κB) on HBV persistence and generation of hepatocellular carcinoma (HCC)-related HBV mutations remain unknown.

PATIENTS AND METHODS

rs28362491 (NFKB1 -94Ins > Del), rs2233406 (NFKBIA -826C > T), rs3138053 (NFKBIA -881A > G), and rs696 (NFKBIA +2758G > A) were genotyped in 1342 healthy controls, 327 HBV-clearance subjects, and 3976 HBV-positive subjects including 1495 HCC patients, using quantitative PCR. HBV mutations were determined by sequencing. The NFKBIA promoter activity was assessed by transient transfection. Multiplicative interactions of the polymorphisms and viral mutations were assessed by multivariate logistic regression.

RESULTS

Compared with HBV-clearance subjects, rs2233406 (CT versus CC) and rs3138053 (AG or AG + GG versus AA) significantly decreased HBV persistence, especially in the genotype B HBV-infected subjects. In the genotype C HBV-infected subjects, rs2233406 variant genotypes were significantly associated with an increased risk of HCC [CT versus CC: age-, gender-adjusted odds ratio (AOR), 1.33; 95% confidence interval (CI) 1.01-1.75 in training set and AOR, 1.59; 95% CI 1.01-2.52 in validation set] compared with HCC-free HBV-infected subjects and significantly increased the frequencies of HCC-related HBV mutations (A1762T/G1764A, T1753V, preS1 start codon mutation, and preS deletion); rs28362491 (Del/Del or Ins/Del + Del/Del versus Ins/Ins) significantly increased the frequency of A1762T/G1764A and reduced the frequency of preS2 start codon mutation. The variant genotypes impaired NFKBIA promoter activity in hepatic cells. The interaction of rs2233406 variant genotypes (CT + TT versus CC) with A1762T/G1764A significantly increased HCC risk in genotype C HBV-infected subjects, with AOR of 2.61 (95% CI 1.09-6.26).

CONCLUSION

Genetic polymorphisms improving NF-κB activity contribute to genotype B HBV clearance. The rs2233406 variant genotypes significantly increase HCC risk, possibly via facilitating immune selection of the HBV mutations. The host-virus interactions are important in identifying HBV-infected subjects who are more likely to develop HCC.

Evaluation of a metal artifacts reduction algorithm applied to postinterventional flat panel detector CT imaging

BACKGROUND AND PURPOSE

Flat panel detector CT images are degraded by streak artifacts caused by radiodense implanted materials such as coils or clips. A new metal artifacts reduction prototype algorithm has been used to minimize these artifacts. The application of this new metal artifacts reduction algorithm was evaluated for flat panel detector CT imaging performed in a routine clinical setting.

MATERIALS AND METHODS

Flat panel detector CT images were obtained from 59 patients immediately following cerebral endovascular procedures or as surveillance imaging for cerebral endovascular or surgical procedures previously performed. The images were independently evaluated by 7 physicians for metal artifacts reduction on a 3-point scale at 2 locations: immediately adjacent to the metallic implant and 3 cm away from it. The number of visible vessels before and after metal artifacts reduction correction was also evaluated within a 3-cm radius around the metallic implant.

RESULTS

The metal artifacts reduction algorithm was applied to the 59 flat panel detector CT datasets without complications. The metal artifacts in the reduction-corrected flat panel detector CT images were significantly reduced in the area immediately adjacent to the implanted metal object (P = .05) and in the area 3 cm away from the metal object (P = .03). The average number of visible vessel segments increased from 4.07 to 5.29 (P = .1235) after application of the metal artifacts reduction algorithm to the flat panel detector CT images.

CONCLUSIONS

Metal artifacts reduction is an effective method to improve flat panel detector CT images degraded by metal artifacts. Metal artifacts are significantly decreased by the metal artifacts reduction algorithm, and there was a trend toward increased vessel-segment visualization.

Targeted resequencing of the microRNAome and 3'UTRome reveals functional germline DNA variants with altered prevalence in epithelial ovarian cancer

Ovarian cancer is a major cause of cancer deaths, yet there have been few known genetic risk factors identified, the best known of which are disruptions in protein coding sequences (BRCA1 and 2). Recent findings indicate that there are powerful genetic markers of cancer risk outside of these regions, in the noncoding mRNA control regions. To identify additional cancer-associated, functional non-protein-coding sequence germline variants associated with ovarian cancer risk, we captured DNA regions corresponding to all validated human microRNAs and the 3' untranslated regions (UTRs) of ~6000 cancer-associated genes from 31 ovarian cancer patients. Multiple single-nucleotide polymorphisms in the 3'UTR of the vascular endothelial growth factor receptor/FLT1, E2F2 and PCM1 oncogenes were highly enriched in ovarian cancer patients compared with the 1000 Genome Project. Sequenom validation in a case-control study (267 cases and 89 controls) confirmed a novel variant in the PCM1 3'UTR is significantly associated with ovarian cancer (P=0.0086). This work identifies a potential new ovarian cancer locus and further confirms that cancer resequencing efforts should not ignore the study of noncoding regions of cancer patients.

Schistosoma japonicum: susceptibility of neonate mice born to infected and noninfected mothers following subsequent challenge

This study was to investigate the differences between neonate mice born to Schistosoma japonicum-infected mothers and those born to noninfected mothers in subsequent challenge. The intensity of infection (evidenced by worm burden and liver egg burden) and liver immunopathology (number and size of liver granulomas) were significantly reduced in neonates from infected mothers (I.M.) compared with neonates from noninfected mothers (N.M.). Anti-soluble worm antigen of S. japonicum (SWA) IgG could be detected in sera of neonates from I.M. (N.N./I.M.) at 1 week after delivery, remained a plateau for 2 weeks and gradually decreased until 8 weeks of age. Parasite-specific IgM was not detected in sera from N.N./I.M. at any time after delivery. At 6 weeks after infection, the level of anti-SWA IgG in infected neonates from I.M. (I.N./I.M.) was significantly higher than that of infected neonates from N.M. (I.N./N.M.). In addition, production of IFN-γ, IL-12 and TGF-β by cultured splenocytes from I.N./I.M. was significantly increased, while the level of IL-4 was significantly decreased when compared to those from I.N./N.M.. These data demonstrate that congenital exposure to schistosomiasis japonica may render neonatal mice born to I.M. less susceptible to subsequent challenge and result in down-regulation of both infection intensity and immunopathology.

Detection and correction of assembly errors of rice Nipponbare reference sequence

A complete and high-quality genome reference sequence of an organism provides a solid foundation for a wide research community and determines the outcomes of relevant genomic, genetic, molecular and evolutionary research. Rice is an important food crop and a model plant for grasses, and therefore was the first chosen crop plant for whole genome sequencing. The genome of the japonica representative rice variety, Nipponbare, was sequenced using a gold standard, map-based clone-by-clone strategy. However, although the Nipponbare reference sequence (RefSeq) has the best quality for existing crop genome sequences, it still contains many assembly errors and gaps. To improve the Nipponbare RefSeq, first a robust method is required to detect the hidden assembly errors. Through alignments between BAC-end sequences (BESs) embedded in the Nipponbare bacterial artificial chromosome (BAC) physical map and the Nipponbare RefSeq, we detected locations on the Nipponbare RefSeq that were inversely matched with BESs and could therefore be candidates for spurious inversions of assembly. We performed further analysis of five potential locations and confirmed assembly errors at those locations; four of them, two on chr4 and two on chr11 of the Nipponbare RefSeq (IRGSP build 5), were found to be caused by reverse repetitive sequences flanking the locations. Our approach is effective in detecting spurious inversions in the Nipponbare RefSeq and can be applied for improving the sequence qualities of other genomes as well.

Overexpression of Ad5 precursor terminal protein accelerates recombinant adenovirus packaging and amplification in HEK-293 packaging cells

Recombinant adenoviruses are one of the most common vehicles for efficient in vitro and in vivo gene deliveries. Here, we investigate whether exogenous precursor terminal protein (pTP) expression in 293 cells improves the efficiency of adenovirus packaging and amplification. We used a piggyBac transposon-based vector and engineered a stable 293 line that expresses high level of Ad5 pTP, designated as 293pTP. Using the AdBMP6-GLuc that expresses green fluorescent protein (GFP), BMP6 and Gaussia luciferase, we found that the infectivity of AdBMP6-GLuc viral samples packaged in 293pTP cells was titrated up to 19.3 times higher than that packaged in parental 293 cells. AdBMP6-GLuc viral samples packaged in 293pTP cells exhibited significantly higher transduction efficiency in 143B and immortalized mouse embryonic fibroblast (iMEF) cells, as assessed by fluorescence-activated cell sorting analysis of GFP-positive cells, the luciferase activity assay and BMP6-induced osteogenic marker alkaline phosphatase activities in iMEFs. When adenovirus amplification efficiency was analyzed, we found that 293pTP cells infected with AdBMP6-GLuc yielded up to 12.6 times higher titer than that in parental 293 cells, especially at lower multiplicities of infection. These results strongly suggest that exogenous pTP expression may accelerate the packaging and amplification of recombinant adenoviruses. Thus, the engineered 293pTP cells should be a superior packaging line for efficient adenovirus production.

The tumor susceptibility gene TMEM127 is mutated in renal cell carcinomas and modulates endolysosomal function

TMEM127 is an endosome-associated tumor suppressor gene in pheochromocytomas, neuroendocrine tumors that can co-occur with renal cell carcinomas (RCCs). TMEM127 loss leads to increased mTOR signaling. However, the spectrum of tumors with TMEM127 mutation and how TMEM127 and mTOR interact in tumorigenesis remains unknown. Here, we report that germline TMEM127 mutations occur in RCCs and that some mutant proteins, unlike wild-type (WT) TMEM127, fail to cooperate with activated early endosomal GTPase, Rab5, to inhibit mTOR signaling. Tmem127-null mouse embryonic fibroblasts (MEFs) are deficient in generating early-to-late hybrid endosomes upon constitutive Rab5 activation, a defect rescued by WT, but not mutant, TMEM127. This endosomal dysfunction results in diminished mTOR colocalization with Rab5-positive vesicles. Conversely, active, lysosomal-bound mTOR is increased in Tmem127-null MEFs, which also display enhanced lysosomal biogenesis. Our data map the tumor-suppressive properties of TMEM127 to modulation of mTOR function in the endolysosome, a feature that may contribute to both pheochromocytoma and RCC pathogenesis.

Bose-Einstein condensates with cavity-mediated spin-orbit coupling

We propose a novel scheme to generate the spin-orbit coupling for a condensate placed inside an optical cavity by using a standing wave and a traveling wave. It is shown that the interplay of the laser lights and the cavity gives rise to rich quantum phases. Our scheme also generates a large synthetic magnetic field for the dressed spin state, which may facilitate the study of the quantum Hall effect in ultracold atomic gases.

Genetic variants of 17q21 are associated with childhood-onset asthma and related phenotypes in a northeastern Han Chinese population: a case-control study

A genome-wide association study (GWAS) suggested that variants on chromosome 17q21 were associated with childhood-onset asthma in white populations. Two replication studies had been conducted in southern Han Chinese population in 2009 and 2012. However, these two Chinese replication results were inconsistent. To further confirm the role of 17q21 common variants, an association study of 17q21 single nucleotide polymorphisms (SNPs) with the risk of childhood-onset asthma was performed in a Han population from northeastern China. In this study, rs3894194, rs12603332 and rs11650680 were genotyped in 435 asthmatic children and 601 healthy controls by using a SNaPshot method. Our data showed that the allelic frequency of rs12603332 and rs11650680 showed significant differences between asthmatic cases and healthy controls, with an odds ratio (OR) of 1.36 [95% confidence interval (CI) 1.12-1.65, P=0.002] and an OR of 1.36 (95% CI 1.07-1.74, P=0.01). Genotype distribution analysis also showed the significant associations of the above two loci with childhood asthma under dominant, recessive and additive model (dominant OR=1.57, 95% CI 1.04-2.36, P=0.032; recessive OR=1.41, 95% CI 1.09-1.83, P=0.009; additive OR=1.97, 95% CI 1.24-3.14, P=0.004; recessive OR=1.50, 95% CI 1.13-1.98, P=0.005). Besides, linear regression analysis showed that rs3894194 and rs12603332 were also significantly associated with asthma phenotypes such as log10 -transformed immunoglobulin E (IgE) level (IU/ml) and log10 -transformed eosinophil percentage (dominant, P=0.04; additive, P=0.01; recessive, P=0.04; recessive, P=0.03; additive, P=0.02). Collectively, our findings suggest that orosomucoid 1-like 3 (ORMDL3) locus on chromosome 17q21 is a risk factor for childhood-onset asthma in northeastern Han Chinese population. Further studies will be needed to elucidate the pathogenesis that ORMDL3 locus predisposes to childhood-onset asthma.

Cerebral vasodilator properties of Danshen and Gegen: a study of their combined efficacy and mechanisms of actions

Danshen and Gegen are two commonly used Chinese herbal medicines for treatment of cardiovascular diseases. The aim of the present study was to elucidate the combination effects of these two herbs on cerebral vascular tone and their underlying mechanisms of actions. Basilar artery rings were obtained from rats and precontracted with U46619. Cumulative administrations of aqueous extracts of Danshen, Gegen, or the two herbs combined (DG; ratio 7:3) produced concentration-dependent relaxation of the artery rings. Statistical analysis on these findings produced a combination index (CI) of 1.041 at ED50, which indicates the two herbs produced additive vasodilator effects when used as a combined decoction. Removal of the endothelium had no effect on the vasodilator properties of Danshen, Gegen, and DG. However, their maximum effects (Imax) were significantly blunted by a KATP channel inhibitor glibenclamide, a non-selective K(+) channel inhibitor tetraethylammonium (TEA), and by a combination of K(+) channel inhibitors (glibenclamide+TEA+iberiotoxin+4-aminopyridine+barium chloride). In addition, Danshen, Gegen, and DG produced augmentation of KATP currents and inhibited Ca(2+) influx in vascular smooth muscle cells isolated from rat basilar arteries. Furthermore, these agents inhibited CaCl2-induced contraction in the artery rings. In conclusion, the present study showed that Danshen and Gegen produced additive vasodilator effects on rat cerebral basilar arteries. These effects were independent of endothelium-derived relaxant factors (EDRF), but required the opening of KATP channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. It is suspected that the cerebral vasodilator effects of Danshen and Gegen produced either on their own or in combination, can help patients with obstructive cerebrovascular diseases.

The LIM protein fhlA is essential for heart chamber development in zebrafish embryos

Four-and-a-half LIM proteins FHL1-3 play important roles in cardiovascular pathophysiology. However, their roles in heart development remain unclear. Here, we report that fhlA, the zebrafish homolog of human FHL1, was found to be expressed around the 22-somite stage. After 24 hpf, expression was restricted to the heart. fhlA knockdown caused an enlarged cardiac chamber phenotype with up-regulated expression of the cardiac markers, but fhlA overexpression reduced the sizes of the cardiac chambers and down-regulated expression of the markers. The morphology associated with the cmlc2, amhc, and vmhc expression patterns at the 22 somite and 24 hpf stages included a broadened domain in embryos lacking fhlA and a smaller domain in embryos overexpressing fhlA. The changes in the sizes of the chambers were attributed to the changes in the number of ventricular and atrial cells. Loss of fhlA caused a longer heart period and pause between heartbeats in M-modes than in controls, but fhlA overexpression caused shorter systolic and diastolic intervals. Abnormal cardiac chambers and physiological function were found to be largely rescued. We also showed the expression of fhlA in the heart to be increased by retinoic acid (RA) and decreased by the RA synthase inhibitor DEAB. Both fhlA and RA signaling caused a phenotype characterized by the morphological alterations in the chamber sizes, suggesting that the role of fhlA in heart development is probably regulated by RA signaling. Taken together, these results showed that fhlA regulates the size of the heart chamber by reducing the number of cardiac cells.