p85α mediates p53 K370 acetylation by p300 and regulates its promoter-specific transactivity in the cellular UVB response

Inducible acetylation of p53 at lysine residues has a great impact on regulating the transactivation of this protein, which is associated with cell growth arrest and/or apoptosis under various stress conditions. However, the factor(s) for regulating p53 acetylation remains largely unknown. In the current study, we have shown that p85α, the regulatory subunit of phosphatidylinositol-3-kinase, has a critical role in mediating p53 acetylation and promoter-specific transactivation in the ultraviolet B (UVB) response. Depletion of p85α in mouse embryonic fibroblasts significantly impairs UVB-induced apoptosis, as well as p53 transactivation and acetylation at Lys370 (Lys373 of human p53); however, the accumulation, nuclear translocation and phosphorylation of p53 are not affected. Interestingly, p85α binds to p300, promotes the p300-p53 interaction and the subsequent recruitment of the p53/p300 complex to the promoter region of the specific p53 target gene in response to UVB irradiation. Moreover, ablation of p53 acetylation at Lys370 by site-directed mutagenesis dramatically suppresses UVB-induced expression of the specific p53-responsive gene as well as cell apoptosis. Therefore, we conclude that p85α is a novel regulator of p53-mediated response under certain stress conditions, and targeting the p85α-dependent p53 pathway may be promising for cancer therapy.

Cellular immune responses to recurring influenza strains have limited boosting ability and limited cross-reactivity to other strains

Influenza vaccine provides protection against infection with matched strains, and this protection correlates with serum antibody titres. In addition to antibodies, influenza-specific CD8+ T-lymphocyte responses are important in decreasing disease severity and facilitating viral clearance. Because this response is directed at internal, relatively conserved antigens, it affords some cross-protection within a given subtype of influenza virus. With the possibility of a broader A(H1N1) Mexico outbreak in the fall of 2009, it appeared worthwhile studying the degree of cellular immune response-mediated cross-reactivity among influenza virus isolates. The composition of the 2006-2007 influenza vaccine included the A/New Caledonia/20/1999 strain (comprising a virus that has been circulating, and was included in vaccine preparations, for 6-7 years) and two strains not previously included (Wisconsin and Malaysia). This combination afforded us the opportunity to determine the degree of cross-reactive cellular immunity after exposure to new viral strains. We analysed the antibody responses and the phenotype and function of the T cell response to vaccine components. The results obtained show that antibody responses to A/New-Caledonia were already high and vaccination did not increase antibody or cytotoxic T lymphocyte responses. These data suggest that repeated exposure to the same influenza stain results in limited boosting of humoral and cellular immune responses.

A comparison of batch effect removal methods for enhancement of prediction performance using MAQC-II microarray gene expression data

Batch effects are the systematic non-biological differences between batches (groups) of samples in microarray experiments due to various causes such as differences in sample preparation and hybridization protocols. Previous work focused mainly on the development of methods for effective batch effects removal. However, their impact on cross-batch prediction performance, which is one of the most important goals in microarray-based applications, has not been addressed. This paper uses a broad selection of data sets from the Microarray Quality Control Phase II (MAQC-II) effort, generated on three microarray platforms with different causes of batch effects to assess the efficacy of their removal. Two data sets from cross-tissue and cross-platform experiments are also included. Of the 120 cases studied using Support vector machines (SVM) and K nearest neighbors (KNN) as classifiers and Matthews correlation coefficient (MCC) as performance metric, we find that Ratio-G, Ratio-A, EJLR, mean-centering and standardization methods perform better or equivalent to no batch effect removal in 89, 85, 83, 79 and 75% of the cases, respectively, suggesting that the application of these methods is generally advisable and ratio-based methods are preferred.

Concomitant increases in spectrum and level of drug resistance in Mycobacterium tuberculosis isolates

OBJECTIVE

To determine the drug resistance spectrum and resistance levels of extensively drug-resistant (XDR-) and multidrug-resistant tuberculosis (MDR-TB) and TB resistant to either rifampicin (RMP, R) or isoniazid (INH, H; R/H-DR).

DESIGN

Of 142 drug-resistant clinical isolates examined, 13 were XDR-TB, 66 were MDR-TB and 63 were R/H-DR. The drug resistance spectrum was tested by the absolute two-concentration method. Minimum inhibitory concentrations (MICs) were determined for the strains by agar dilution method on Löwenstein-Jensen slants.

RESULTS

The drug resistance spectrum of XDR-TB, MDR-TB and R/H-DR TB isolates ranged from 4 to 9, 2 to 6 and 1 to 5 drugs, respectively. Over half of all XDR-TB (53.8%), MDR-TB (66.7%) and R/H-DR (54.0%) isolates were resistant to two other anti-tuberculosis drugs; 38.5% of XDR-TB, 24.2% of MDR-TB and 28.6% of R/H-DR TB isolates were resistant to ≥ 3 additional anti-tuberculosis drugs in addition to those originally defined, demonstrating that the MIC values and the proportions of strains with higher MICs followed a trend of XDR-TB > MDR-TB > R/H-DR for INH, RMP, ofloxacin and ethambutol.

CONCLUSION

XDR-TB, MDR-TB and R/H-DR TB isolates exhibited both increasingly broader resistance spectra and a higher percentage of strains with high MICs to more frequently resistant drugs, which might be related to patterns of TB chemotherapy.

Expression and activation of β-adrenoceptors in the colorectal mucosa of rat and human

BACKGROUND

The functions of the distal colon are regulated by local and extrinsic neural pathways. In previous studies, we have found that dopamine (DA) and norepinephrine (NE) could evoke colonic ion transport by activating β-adrenoceptors. The present study aims to investigate the segmental differences in expression and activation of β-adrenoceptors in the distal colon in physiological and pathophysiological conditions.

METHODS

Real-time PCR, immunofluorescence, and Western blotting were used to detect the expression of β-adrenoceptors in the rat and human distal colon. Short-circuit current measurements (Isc) were used to assess the role of β-adrenoceptors in ion transport.

KEY RESULTS

DA and NE caused greater suppression of baseline Isc in distal colon adjacent to the rectum than in segments further away from the anus. These responses were inhibited by selective antagonists of β₁- and β₂-adrenoceptors, but not β₃-adrenoceptor. The expression levels of β₁- and β₂-adrenoceptors in colonic mucosa were higher in colorectum than the regions away from the anus of rats and humans. In wrap-restraint stress (2 h), DA-, NE-induced ΔIsc and the expression of β-adrenoceptors in the colorectum were significantly reduced. However, when endogenous catecholamines were depleted by 6-hydroxydopamine (75 mg kg(-1), i.p., 3 days), DA-, NE-induced ΔIsc as well as the expression of β-adrenoceptors were significantly enhanced in the rat colorectum but not in more proximal regions of the distal colon.

CONCLUSIONS & INFERENCES

β₁- and β₂-adrenoceptors are predominantly expressed in the colorectal mucosa. Perturbation of endogenous catecholamine levels influences the expression and activation of β-adrenoceptors in the colorectal region.

Non-invasive monitoring of blood haemoglobin for analysis of fluid volume kinetics

BACKGROUND

A commercially available pulse oximeter that reports blood haemoglobin (Hb) concentration is evaluated. This study considers whether this device can provide serial Hb data that would be sufficiently reliable for volume kinetic analysis of infusion fluids.

METHODS

Forty infusions of 5 or 10 ml/kg of acetated Ringer's solution were given over 15 min in 10 healthy volunteers. Hb was measured on 17 different occasions over 120 min using the Radical 7 pulse oximeter and compared with the result of invasive blood sampling (control). A one-volume kinetic model was applied to each data series. The pulse oximeter also reported the perfusion index (PI).

RESULTS

The median deviation between the 680 invasive and non-invasive Hb samples (the accuracy) was 1.6% and the absolute median deviation (precision) was 4.6%. Between-subject factors explained half of the variation in the difference between non-invasive vs. invasive sampling. Ten of the 40 non-invasive series of Hb values were discarded from kinetic analysis due to poor quality. The remaining 30 series showed a smaller distribution volume for the infused fluid when kinetic analysis was based on the non-invasive method (3.0 vs. 5.3l; P<0.001). This was due to co-variance with the PI, which exaggerated the decrease in Hb caused by the infusions. The non-invasive method might provide useful kinetic data at the group level, but individual curves deviated too much from the invasive data to be reliable.

CONCLUSIONS

Non-invasive measurement of the Hb concentration during volume loading could not provide useful kinetic data for individuals.

Human adipose tissue-derived adult stem cells can lead to multiorgan engraftment

Recent studies have demonstrated the existence of a population of adipose tissue-derived adult stem cells that can undergo multilineage differentiation in vitro; however, it is unclear whether these cells maintain their multilineage differentiation in vivo. The objective of the present study was to examine the in vivo characteristics and behavior of a potential population of human adipose tissue-derived adult stem cells. Herein, we demonstrate that human adipose tissue-derived adult stem cells differentiate into the epithelium of the gastrointestinal tract, liver, and bronchi, and an endothelial lineage after transplantation into irradiated nonobese mice with diabetes or severe combined immunodeficiency. These findings may contribute to clinical tissue repair after injury.

Phenotypic spectrum of patients with PLA2G6 mutation and PARK14-linked parkinsonism

BACKGROUND

PLA2G6 is the causative gene for infantile neuroaxonal dystrophy, neurodegeneration associated with brain iron accumulation, and Karak syndrome. Based on previous reports, patients with PLA2G6 mutations could show axonal dystrophy, dystonia, dementia, and cerebellar signs. Recently, PLA2G6 was also reported as the causative gene for early-onset PARK14-linked dystonia-parkinsonism.

METHODS

To clarify the role of PLA2G6 mutation in parkinsonism, we conducted mutation analysis in 29 selected patients with very early-onset (≤ 30, mean 21.2 ± 8.4 years, ± SD) parkinsonism. These patients had other clinical features (e.g., mental retardation/dementia [14/29], psychosis [15/29], dystonia [11/29], and hyperreflexia [11/29]).

RESULTS

Two novel compound heterozygous PLA2G6 mutations were detected (patient A: p.F72L/p.R635Q; patients B1 and B2: p.Q452X/p.R635Q). All 3 patients had early-onset l-dopa-responsive parkinsonism with dementia and frontotemporal lobar atrophy. Disease progression was relatively rapid. SPECT in patient B1 showed frontotemporal lobar hypoperfusion. MRI in patient A showed iron accumulation in the substantia nigra and striatum.

CONCLUSIONS

Although the clinical presentation of PLA2G6-associated neurodegeneration was reported to be homogeneous, our findings suggest patients with PLA2G6 mutation could show heterogeneous phenotype such as dystonia-parkinsonism, dementia, frontotemporal atrophy/hypoperfusion, with or without brain iron accumulation. Based on the clinical heterogeneity, the functional roles of PLA2G6 and the roles of PLA2G6 variants including single heterozygous mutations should be further elucidated in patients with atypical parkinsonism, dementia, or Parkinson disease. PLA2G6 mutations should be considered in patients with early-onset l-dopa-responsive parkinsonism and dementia with frontotemporal lobar atrophy.

Endovascular treatment of intracranial aneurysms associated with moyamoya disease or moyamoya syndrome

Direct surgical clipping proves to be difficult and dangerous for intracranial aneurysms associated with moyamoya disease (MMD) or moyamoya syndrome (MMS). This study presents our clinical experience of endovascular embolization of intracranial aneurysms associated with these diseases. A total of 13 cases of intracranial aneurysms associated with MMD or MMS were treated by endovascular embolization between January 2001 and January 2009. Patients were divided into two groups: a saccular aneurysm group (n=10) and a pseudoaneurysm group (n=3). Different endovascular therapeutic strategies were employed for each type of case. Of the 13 cases, 11 received successful endovascular embolization and had an uneventful postoperative course during one to two years of follow-up. However, endovascular embolization failed in the other two cases, of whom one died from rebleeding after the five-month follow-up, while the other was conservatively treated and experienced no rebleeding during the two-year follow-up. A favorable prognosis may be secured through careful selection of endovascular treatment regimens for patients with intracranial aneurysms associated with MMD or MMS according to the site of intracranial aneurysms.

Molecular characterization of erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae in China and complete DNA sequence of Tn2010

AIMS

To characterize the erm(B)- and mef(E)-mediated erythromycin-resistant Streptococcus pneumoniae clinical isolates obtained from ten hospitals located different cities in China.

METHODS AND RESULTS

Totally 83 S. pneumoniae were collected, and eighteen representative strains of 66 strains that exhibited erythromycin resistance were used for further characterization by antibiograms, serotyping, PFGE, MLST, DNA sequencing of the macrolide-resistance elements and mapping of the elements on the chromosome. Twelve isolates showed a high-level resistance to erythromycin, and six other isolates showed a low-level resistance to erythromycin. Thirteen isolates harboured a Tn2010 transposon (26·4 kbp) encoding the erm(B), tet(M) and mef(E) genes and were classified into three types by Tn2010 structures. The remaining five isolates harboured a Tn6002 transposon (20·9 kbp) encoding the erm(B) and tet(M) genes and were classified into three types by Tn6002 locations on the chromosome. Three of the Tn6002 elements were located within the Tn5252-like element, implying that these composed a large mobile element. The MLST analyses showed that several clones had been disseminated and that the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China. Four new MLST strains, which were designated as ST3262, ST3263, ST3397 and ST3398 were also identified.

CONCLUSIONS

The erythromycin resistance determinant of S.pneumoniae that had been isolated in China was located in Tn2010 or the Tn6002 element and several clones had been disseminated, and the CC271 strains carrying the Tn2010 element expressing the high-level resistance to erythromycin were predominant in China.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first molecular analysis of erythromycin-resistant Streptococcus pneumoniae clinical isolates in China, and the first report of the complete nucleotide sequence of Tn2010 (26,390 bp).

Adaptive immune response in osteoclastic bone resorption induced by orally administered Aggregatibacter actinomycetemcomitans in a rat model of periodontal disease

There is mounting evidence that innate and adaptive immunity are critical for periodontal disease-mediated bone resorption. These studies examined the role of B and CD4 T cells in adaptive immunity of rats infected with Aggregatibacter actinomycetemcomitans (Aa). Sprague-Dawley male rats were fed Aa-containing mash or control-mash for 2 weeks. B and CD4 T cells were obtained from draining lymph nodes at 2, 4 and 12 weeks, postinoculation. Quantitative polymerase chain reaction-based messenger RNA expression was conducted for 89 cytokine family genes. Disease-relevance of the differentially expressed genes was assessed using a biological interaction pathway analysis software. B and CD4 T cells of Aa-infected rats increased and were activated, resulting in enhanced isotype-switched serum immunoglobulin G by 2 weeks postinoculation. Bone resorption was evident 12 weeks after Aa-feeding. In B cells, interleukin-2 (IL-2), macrophage-inhibiting factor, IL-19, IL-21, tumor necrosis factor (TNF), CD40 ligand (CD40L), CD70, bone morphogenetic protein 2 (BMP2), BMP3, and BMP10 were upregulated early; while IL-7, Fas ligand (FasL), small inducible cytokine subfamily E1, and growth differentiation factor 11 (GDF11; BMP11) were upregulated late (12 weeks). BMP10 was sustained throughout. In CD4 T cells, IL-10, IL-16, TNF, lymphotoxin-beta (LTbeta), APRIL, CD40L, FasL, RANKL and osteoprotegerin were upregulated early, whereas IL-1beta, IL-1RN, IL-1F8, IL-24, interferon-alpha1, GDF11 (BMP11), and GDF15 were upregulated late (12 weeks). Adaptive immunity appears crucial for bone resorption. Several of the deregulated genes are, for the first time, shown to be associated with bone resorption, and the results indicate that activated B cells produce BMP10. The study provides a rationale for a link between periodontal disease and other systemic diseases.

Enhancement of the critical temperature of HgBa₂CuO(4+δ) by applying uniaxial and hydrostatic pressure: implications for a universal trend in cuprate superconductors

It is well known that the superconducting transition temperature (T(c)) of cuprate superconductors can be enhanced by varying certain structural and electronic parameters, such as the flatness of the CuO₂ planes or their doping level. We determine the uniaxial and hydrostatic pressure derivatives of T(c) in the structurally simple tetragonal compound HgBa₂CuO(4+δ) near optimal doping. Our results provide experimental evidence for two further methods to enhance T(c): (i) reducing the area of the CuO₂ planes, and (ii) increasing the separation of the CuO₂ planar groups. T(c) is found to couple much more strongly to the ratio c/a of the lattice constants than to the unit cell volume. A comparison with prior results for structurally more complicated cuprates reveals a general trend of uniaxial pressure derivatives with T(c).

Expression of Osteoclastogenesis Inducers in a Tissue Model of Periodontal Ligament under Compression

There is increasing interest in the development of new in vitro tissue models. In this study, a tissue model of periodontal ligament (PDL) was established by 3-D-culturing human PDL cells in a thin sheet of porous poly (lactic-co-glycolic acid) scaffold. Growth of the model was evidenced by MTT assay and various microscopies. After being subjected to static compression of 5 ~ 35 g/cm2 for 6 hrs, the RANKL mRNA expression was significantly up-regulated by force ≥ 25 g/cm2 in the model. After being subjected to static compression of 25 g/cm2 for 6 ~ 72 hrs, the mRNA expression of PTHrP, IL-11, IL-8, and FGF-2, potential osteoclastogenesis inducers, was significantly up-regulated in the model, which was further verified by the compression of human PDL in vivo. However, when human gingival fibroblasts were substituted for PDL cells in the model, almost no osteoclastogenesis inducers were up-regulated by compression. This tissue model can serve as an effective tool for the study of PDL mechanoresponse. Abbreviations: periodontal ligament, PDL; periodontal ligament cells, PDLCs; poly (lactic-co-glycolic acid), PLGA; orthodontic tooth movement, OTM; extracellular matrix, ECM.

Negative regulation of the tumor suppressor p53 gene by microRNAs

The tumor suppressor p53, encoded by the TP53 gene, is recognized as the guardian of the human genome because it regulates many downstream genes to exercise its function in cell cycle and cell death. Recent reports have revealed that several microRNAs (miRNAs) are important components of the p53 tumor suppressor network with miR-125b and miR-504 directly targeting TP53. In this report, we use a screening method to identify that two miRNAs (miR-25 and miR-30d) directly target the 3'UTR of TP53 to down-regulate p53 protein levels and reduce the expression of genes that are transcriptionally activated by p53. Correspondingly, both miR-25 and miR-30d adversely affect apoptotic cell death, cell cycle arrest, and cellular senescence. Inhibition of either miR-25 or miR-30d expression increases endogenous p53 expression and elevates cellular apoptosis in several cell lines, including one from multiple myeloma that has little TP53 mutations. Thus, beyond miR-125b and miR-504, the human TP53 gene is negatively regulated by two more miRNAs: miR-25 and miR-30d.

Electrophoretic deposition of biomaterials

Electrophoretic deposition (EPD) is attracting increasing attention as an effective technique for the processing of biomaterials, specifically bioactive coatings and biomedical nanostructures. The well-known advantages of EPD for the production of a wide range of microstructures and nanostructures as well as unique and complex material combinations are being exploited, starting from well-dispersed suspensions of biomaterials in particulate form (microsized and nanoscale particles, nanotubes, nanoplatelets). EPD of biological entities such as enzymes, bacteria and cells is also being investigated. The review presents a comprehensive summary and discussion of relevant recent work on EPD describing the specific application of the technique in the processing of several biomaterials, focusing on (i) conventional bioactive (inorganic) coatings, e.g. hydroxyapatite or bioactive glass coatings on orthopaedic implants, and (ii) biomedical nanostructures, including biopolymer-ceramic nanocomposites, carbon nanotube coatings, tissue engineering scaffolds, deposition of proteins and other biological entities for sensors and advanced functional coatings. It is the intention to inform the reader on how EPD has become an important tool in advanced biomaterials processing, as a convenient alternative to conventional methods, and to present the potential of the technique to manipulate and control the deposition of a range of nanomaterials of interest in the biomedical and biotechnology fields.