Psoriasis pathogenesis – Pso p27 constitutes a compact structure forming large aggregates

Psoriasis is a chronic inflammatory skin disease. The absence of microbial organisms as potential causal agents has given rise to the hypothesis that the inflammation is due to an autoimmune reaction. The defined inflamed areas of the skin lesions argue for an immunological disease with a local production of a causal antigen. Pso p27 is a protein generated in mast cells in psoriatic plaques, but not in uninvolved skin. We recently demonstrated that the Pso p27 is generated by cleavage of SerpinB3 (SCCA1) in the presence of mast cell associated chymase.In this communication we demonstrate by X-ray crystallographic analysis that the cleavage products associate into a complex similar to SCCA1, but with the reactive centre loop inserted into a 5-stranded central β-sheet.Native gel electrophoresis show that these Pso p27 complexes form large aggregates which may be of significance with respect to an immunogenic role of Pso p27.     

How is life history variation generated from the genetic resource allocation?

A simple quantitative genetic model is proposed to explain the observed genetic correlation structure of a bruchid beetleCallosobruchus chinensis in terms of two underlying variables: the resource acquisition and the resource allocation. Heritabilities and genetic correlations among age-specific, fecundities are regarded as consequences of genetic variations of the two variables. Genetic correlations are predominantly positive in both predictions and observations. Nonetheless, comparison between observed and predicted values in heritabilities, genetic correlations, and genetic principal components suggested significant genetic variances both of the resource allocation and the resource acquisition. The prediction of the model is discussed in relation, to experimental tests of trade-off in life history evolution.     

HIV-1 p24和SIV p27两种ELISA试剂盒检测SIV p27抗原的比较

目的由于检测SIV p27抗原试剂盒来源困难,有时不稳定,鉴于HIV-1 p24与SIVp27有较强的交叉抗原,本研究比较HIV-1 p24和SIV p27两种ELISA试剂盒检测SIV p27抗原得出的结果是否存在一定的相关性。方法 HIV-1 p24和SIV p27两种ELISA试剂盒定性和定量检测样品中SIV p27抗原,并对检测结果进行回归和相关分析。结果 HIV-1 p24和SIV p27两种ELISA试剂盒检测SIV p27抗原的灵敏度分别是150 pg/mL和62.5 pg/mL。两种试剂盒检测病毒液和血浆中SIV p27抗原的定性结果一致。定量结果的统计分析得出病毒液的直线回归决定系数R2=0.857,直线相关系数r=0.926,P〈0.01,直线正相关程度较高;血浆的直线回归决定系数R2=0.512,直线相关系数r=0.716,P〈0.05,直线正相关程度较低。结论 HIV-1 p24 ELISA试剂盒能够替代SIVp27 ELISA试剂盒定性检测病毒液和血浆中SIV p27抗原,但只能定量检测病毒液中SIV p27抗原。     

Physical activity is associated with slower epigenetic ageing—Findings from the Rhineland study

Epigenetic ageing, i.e., age-associated changes in DNA methylation patterns, is a sensitive marker of biological ageing, a major determinant of morbidity and functional decline. We examined the association of physical activity with epigenetic ageing and the role of immune function and cardiovascular risk factors in mediating this relation. Moreover, we aimed to identify novel molecular processes underlying the association between physical activity and epigenetic ageing. We analysed cross-sectional data from 3567 eligible participants (mean age: 55.5 years, range: 30–94 years, 54.8% women) of the Rhineland Study, a community-based cohort study in Bonn, Germany. Physical activity components (metabolic equivalent (MET)-Hours, step counts, sedentary, light-intensity and moderate-to-vigorous intensity activities) were recorded with accelerometers. DNA methylation was measured with the Illumina HumanMethylationEPIC BeadChip. Epigenetic age acceleration (Hannum's age, Horvath's age, PhenoAge and GrimAge) was calculated based on published algorithms. The relation between physical activity and epigenetic ageing was examined with multivariable regression, while structural equation modeling was used for mediation analysis. Moreover, we conducted an epigenome-wide association study of physical activity across 850,000 CpG sites. After adjustment for age, sex, season, education, smoking, cell proportions and batch effects, physical activity (step counts, MET-Hours and %time spend in moderate-to-vigorous activities) was non-linearly associated with slower epigenetic ageing, in part through its beneficial effects on immune function and cardiovascular health. Additionally, we identified 12 and 7 CpGs associated with MET-Hours and %time spent in moderate-to-vigorous activities, respectively (p < 1 × 10⁻⁵). Our findings suggest that regular physical activity slows epigenetic ageing by counteracting immunosenescence and lowering cardiovascular risk.     

Acetylcholinesterase is associated with apoptosis in β cells and contributes to insulin-dependent diabetes mellitus pathogenesis

Acetylcholinesterase (AChE) expression is pivotal during apoptosis. Indeed, AChE inhibitors partially protect cells from apoptosis. Insulin-dependent diabetes mellitus (IDDM) is characterized in part by pancreatic β-cell apoptosis. Here, we investigated the role of AChE in the development of IDDM and analyzed protective effects of AChE inhibitors. Multiple low-dose streptozotocin (MLD-STZ) administration resulted in IDDM in a mouse model. Western blot analysis, cytochemical staining, and immunofluorescence staining were used to detect AChE expression in MIN6 cells, primary β cells, and apoptotic pancreatic β cells of MLD-STZ-treated mice. AChE inhibitors were administered intraperitoneally to the MLD-STZ mice for 30 days. Blood glucose, plasma insulin, and creatine levels were measured, and glucose tolerance tests were performed. The effects of AChE inhibitors on MIN6 cells were also evaluated. AChE expression was induced in the apoptotic MIN6 cells and primary β cells in vitro and pancreatic islets in vivo when treated with STZ. Induction and progressive accumulation of AChE in the pancreatic islets were associated with apoptotic β cells during IDDM development. The administration of AChE inhibitors effectively decreased hyperglycemia and incidence of diabetes, and restored plasma insulin levels and plasma creatine clearance in the MLD-STZ mice. AChE inhibitors partially protected MIN6 cells from the damage caused by STZ treatment. Induction and accumulation of AChE in pancreatic islets and the protective effects of AChE inhibitors on the onset and development of IDDM indicate a close relationship between AChE and IDDM.     

Whole fruit staining with aniline blue at harvest is associated with superficial pathogenesis of “Fuji” apples after storage

Abstract

Whole “Fuji” apples (Malus domestica Borkh cv. Fuji) were treated with 0.2% aniline blue before storage in 2006, 2007 and 2008 to determine whether cuticular microcracking was associated with post-storage disorders. After storage for 7 months at 0° C and 90% relative humidity followed by 3 days at 20° C, a higher aniline blue staining scale value was associated with a higher peel browning and decay index. These results indicate that superficial disorders or diseases of apples may be related to cuticular microcracking that can be seen by aniline blue staining. Scanning electron microscopy was used to analyze the ultrastructure of stained portions of the cuticular complex. Disorders or diseases of the cuticle of epidermal tissue was associated with cracked lenticels, unhealed microcracks around the edge of the lenticel, and collapsed epicuticular wax; these areas stained more intensely. Our results indicated the potential of using an aniline blue staining prior to storing the fruit to predict the ultimate quality.     

E-Cadherin–dependent Growth Suppression is Mediated by the Cyclin-dependent Kinase Inhibitor p27KIP1

Recent studies have demonstrated the importance of E-cadherin, a homophilic cell–cell adhesion molecule, in contact inhibition of growth of normal epithelial cells. Many tumor cells also maintain strong intercellular adhesion, and are growth-inhibited by cell– cell contact, especially when grown in three-dimensional culture. To determine if E-cadherin could mediate contact-dependent growth inhibition of nonadherent EMT/6 mouse mammary carcinoma cells that lack E-cadherin, we transfected these cells with an exogenous E-cadherin expression vector. E-cadherin expression in EMT/6 cells resulted in tighter adhesion of multicellular spheroids and a reduced proliferative fraction in three-dimensional culture. In addition to increased cell–cell adhesion, E-cadherin expression also resulted in dephosphorylation of the retinoblastoma protein, an increase in the level of the cyclin-dependent kinase inhibitor p27^kip1 and a late reduction in cyclin D1 protein. Tightly adherent spheroids also showed increased levels of p27 bound to the cyclin E-cdk2 complex, and a reduction in cyclin E-cdk2 activity. Exposure to E-cadherin–neutralizing antibodies in three-dimensional culture simultaneously prevented adhesion and stimulated proliferation of E-cadherin transfectants as well as a panel of human colon, breast, and lung carcinoma cell lines that express functional E-cadherin. To test the importance of p27 in E-cadherin–dependent growth inhibition, we engineered E-cadherin–positive cells to express inducible p27. By forcing expression of p27 levels similar to those observed in aggregated cells, the stimulatory effect of E-cadherin–neutralizing antibodies on proliferation could be inhibited. This study demonstrates that E-cadherin, classically described as an invasion suppressor, is also a major growth suppressor, and its ability to inhibit proliferation involves upregulation of the cyclin-dependent kinase inhibitor p27.     

Tau pathogenesis is promoted by Aβ1-42 but not Aβ1-40

Background

The relationship between the pathogenic amyloid β-peptide species Aβ1–42 and tau pathology has been well studied and suggests that Aβ1–42 can accelerate tau pathology in vitro and in vivo. The manners if any in which Aβ1–40 interacts with tau remains poorly understood. In order to answer this question, we used cell-based system, transgenic fly and transgenic mice as models to study the interaction between Aβ1–42 and Aβ1–40.

Results

In our established cellular model, live cell imaging (using confocal microscopy) combined with biochemical data showed that exposure to Aβ1–42 induced cleavage, phosphorylation and aggregation of wild-type/full length tau while exposure to Aβ1–40 didn’t. Functional studies with Aβ1–40 were carried out in tau-GFP transgenic flies and showed that Aβ1–42, as previously reported, disrupted cytoskeletal structure while Aβ1–40 had no effect at same dose. To further explore how Aβ1–40 affects tau pathology in vivo, P301S mice (tau transgenic mice) were injected intracerebrally with either Aβ1–42 or Aβ1–40. We found that treatment with Aβ1–42 induced tau phosphorylation, cleavage and aggregation of tau in P301S mice. By contrast, Aβ1–40 injection didn’t alter total tau, phospho-tau (recognized by PHF-1) or cleavage of tau, but interestingly, phosphorylation at Ser²⁶² was shown to be significantly decreased after direct inject of Aβ1–40 into the entorhinal cortex of P301S mice.

Conclusions

These results demonstrate that Aβ1–40 plays different role in tau pathogenesis compared to Aβ1–42. Aβ1–40 may have a protective role in tau pathogenesis by reducing phosphorylation at Ser²⁶², which has been shown to be neurotoxic.

     

Protein Phosphatase 1 δ is Associated with Focal Adhesions

In all mammalian cells protein phosphatase-1 (PP1) exists in three isoforms, defined as α, γ1 and δ. Immunofluorescence studies with isoform-specific antibodies indicated that δ, but not α or γ1, is enriched at focal adhesions in HeLa cells, fibroblasts, endothelial cells and keratinocytes. This was confirmed also by interference reflection microscopy, which indicated that PP1δ was in areas of tight adhesion of the membrane to the extracellular matrix at sites where the microfilament cytoskeleton is organized. In all the cell types so far considered the PP1δ in focal adhesions represented only a small aliquot of the total PP1δ, which was predominantly localized to the nucleus. The association of PP1δ to focal adhesions was confirmed by the co-immunoprecipitation of PP1δ with the focal adhesion kinase pp125^FAK and with the αv integrin. Comparison between the amount of PP1δ associated with focal adhesion proteins and that of PP1δ recovered in an anti-PP1δ immunoprecipitate confirmed that only a minor amount of the enzyme was associated with the focal adhesions. Since some focal adhesion proteins are phosphorylated on Ser/Thr, it is likely that PP1δ may be involved in the regulation of focal adhesion functions and particularly in the signaling pathway generated by cell-substratum adhesion.     

CCL27 expression is regulated by both p38 MAPK and IKKβ signalling pathways

The skin-specific chemokine CCL27 is believed to play a pivotal role in establishing the inflammatory infiltrate characteristic for common inflammatory skin diseases. Through binding to the chemokine receptor 10 (CCR10), CCL27 mediates inflammation by promoting lymphocyte migration into the skin. Little is known about the regulation of CCL27 gene expression. The purpose of our study was to investigate the regulation of the IL-1β-induced CCL27 gene expression in normal human keratinocytes (NHEK). Preincubation of NHEK with the inhibitory κB (IκB) kinase (IKK) inhibitor, SC-514, or the p38 mitogen-activated protein kinase (MAPK) inhibitor, SB202190, revealed a profound reduction in both CCL27 mRNA and CCL27 protein expression indicating the significance of these pathways in the regulation of CCL27 expression. Furthermore, the impact of inhibitors of mitogen- and stress-activated kinase 1 (MSK1) or the mitogen-activated protein kinase-interacting kinases (Mnk1+2), downstream kinases of p38 MAPK, on IL-1β-induced CCL27 expression in NHEK were investigated. We identified seven NF-κB binding elements upstream from the CCL27 gene start codon using electrophoretic mobility shift assay (EMSA). Supershift analyses demonstrated the involvement of the p50/p65 NF-κB heterodimer. We conclude that IL-1β-induced CCL27 gene expression in NHEK is regulated through the p38 MAPK/MSK1/Mnk1+2 as well as the IKKβ/NF-κB signalling pathways.     

S100A6 is secreted from Wharton's jelly mesenchymal stem cells and interacts with integrin β1

S100A6 is a calcium binding protein belonging to the S100 family. In this work we examined the function of extracellular S100A6. Using mesenchymal stem cells isolated from Wharton's jelly of the umbilical cord (WJMS cells) we have shown that S100A6 is secreted by these cells, and when added to the medium, increases their adhesion and inhibits proliferation. The search for a potential target/receptor of S100A6 in the membrane fraction of WJMS cells allowed us to identify some proteins, among them integrin β1, which interacts with S100A6 in a calcium dependent manner. The interaction between S100A6 and integrin β1, was then confirmed by ELISA using purified proteins. Applying specific antibodies against integrin β1 reversed the effect on cell adhesion and proliferation observed in the presence of S100A6 which indicates that S100A6 exerts its function due to interaction with integrin β1. Since the data show the influence of extracellular S100A6 on cells isolated from Wharton's jelly, our results might help to establish molecular mechanisms leading to some pathologies characteristic for this tissue.     

p27kip1、Cyclin D1在卵巢癌中的表达及临床意义

目的探讨p27kip1、Cyclin D1在卵巢癌发生方面的意义.方法应用免疫组织化学方法及半定量分析方法,检测50例卵巢癌、19例卵巢良性上皮肿瘤、 13例正常卵巢组织中的p27kip1和Cyclin D1表达,并分析它们与良恶性肿瘤、病理学分级、临床分期的相关性. 结果正常卵巢和卵巢良性肿瘤间,p27和Cyclin D1的各自表达无明显差异;p27在正常卵巢组织和卵巢良性上皮肿瘤中高表达,在卵巢癌中表达降低(P<0.05),且随着肿瘤分级、分期增高(恶性程度增高),阳性表达率逐渐下降;而Cyclin D1的表达则相反;两者在肿瘤中的表达呈负相关.结论 p27kip表达下降、Cyclin D1过表达可能在卵巢癌的发生中起重要作用,检测p27kip1、Cyclin D1在卵巢癌中的表达可预测肿瘤生物学行为特征,可以作为判断预后的指标.     

Crystal structure of the p38α MAP kinase in complex with a docking peptide from TAB1

The mitogen-activated protein kinase (MAPK) p38α is a key regulator in many cellular processes, whose activity is tightly regulated by upstream kinases, phosphatases and other regulators. Transforming growth factor-β activated kinase 1 (TAK1) is an upstream kinase in p38α signaling, and its full activation requires a specific activator, the TAK1-binding protein (TAB1). TAB1 was also shown to be an inducer of p38α’s autophosphorylation and/or a substrate driving the feedback control of p38α signaling. Here we determined the complex structure of the unphosphorylated p38α and a docking peptide of TAB1, which shows that the TAB1 peptide binds to the classical MAPK docking groove and induces long-range conformational changes on p38α. Our structural and biochemical analyses suggest that TAB1 is a reasonable substrate of p38α, yet the interaction between the docking peptide and p38α may not be sufficient to trigger trans-autophosphorylation of p38α.     

Production of biofuels from C1-gases with Clostridium and related bacteria—Recent advances

Clostridium spp. are suitable for the bioconversion of C₁-gases (e.g., CO₂, CO and syngas) into different bioproducts. These products can be used as biofuels and are reviewed here, focusing on ethanol, butanol and hexanol, mainly. The production of higher alcohols (e.g., butanol and hexanol) has hardly been reviewed. Parameters affecting the optimization of the bioconversion process and bioreactor performance are addressed as well as the pathways involved in these bioconversions. New aspects, such as mixotrophy and sugar versus gas fermentation, are also reviewed. In addition, Clostridia can also produce higher alcohols from the integration of the Wood-Ljungdahl pathway and the reverse ß-oxidation pathway, which has also not yet been comprehensively reviewed. In the latter process, the acetogen uses the reducing power of CO/syngas to reduce C₄ or C₆ fatty acids, previously produced by a chain elongating microorganism (commonly Clostridium kluyveri), into the corresponding bioalcohol.     

Why is obesity associated with osteoarthritis? Insights from mouse models of obesity

Obesity is one of the most significant, and potentially most preventable, risk factors for the development of osteoarthritis, and numerous studies have shown a strong association between body mass index and osteoarthritis of the hip, knee, foot and hand. However, the mechanism(s) by which obesity contributes to the onset and progression of osteoarthritis are not fully understood. The strong association between body mass index, altered limb alignment, and osteoarthritis of the knee--and the protective effects of weight loss--support the classic hypothesis that the effects of obesity on the joint are due to increased biomechanical loading and associated alterations in gait. However, obesity is now considered to be a low-grade systemic inflammatory disease, and recent studies suggest that metabolic factors associated with obesity alter systemic levels of pro-inflammatory cytokines that are also associated with osteoarthritis. Thus, the ultimate influence of obesity on osteoarthritis may involve a complex interaction of genetic, metabolic, and biomechanical factors. In this respect, mouse models of obesity can provide excellent systems in which to examine causal relationships among these factors. In recent years, there have been surprisingly few reports examining the effects of obesity on osteoarthritis using mouse models. In this paper, we review studies on mice and other animal models that provide both direct and indirect evidence on the role of obesity and altered diet in the development of osteoarthritis. We also examine the use of different body mass indices for characterizing "obesity" in mice by comparing these indices to typical adiposity levels observed in obese humans. Taken together, evidence from studies using mice suggest that a complex interaction of environmental and genetic factors associated with obesity contribute to the incidence and severity of osteoarthritis. The ability to control these factors, together with the development of methods to conduct more intricate measures of local biomechanical factors, make mouse models an excellent system to study obesity and osteoarthritis.