A More Desirable Balanced Polyunsaturated Fatty Acid Composition Achieved by Heterologous Expression of Δ15/Δ4 Desaturases in Mammalian Cells

Arachidonic (ARA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids are the most biologically active polyunsaturated fatty acids, but their biosyntheses in mammals are very limited. The biosynthesis of DHA is the most difficult, because this undergoes the Sprecher pathway–a further elongation step from docosapentaenoic acid (DPA), a Δ6-desaturase acting on a C24 fatty acid substrate followed by a peroxisomal chain shortening step. This paper reports the successful heterologous expression of two non-mammalian genes (with modification of codon usage), coding for Euglena gracilis Δ4-desaturase and Siganus canaliculatus Δ4-desaturase respectively, in mammalian cells (HEK293 cell line). Both of the Δ4-desaturases can efficiently function, directly converting DPA into DHA. Moreover, the cooperation of the E. gracilis Δ4-desaturase with C. elegans Δ15-desaturase (able to convert a number of n-6 PUFAs to their corresponding n-3 PUFAs) in transgenic HEK293 cells made a more desirable fatty acid composition – a drastically reduced n-6/n-3 PUFAs ratio and a high level of DHA as well as EPA and ARA. Our findings provide a basis for potential applications of the gene constructs for expression of Δ15/Δ4-desaturases in transgenic livestock to produce such a fatty acid profile in the related products, which certainly will bring benefit to human health.     

载脂蛋白A-Ⅰ结合蛋白介导胆固醇流出调控血管新生

胆固醇流出在维持细胞正常结构和功能中发挥着关键的生理作用,然而其在调节血管新生中的作用一直未明. 近日,美国加州大学医学院的研究人员发现（Nature, 2013,498:118-122), 载脂蛋白A-I结合蛋白（apoA-I binding protein,AIBP）介导的内皮细胞胆固醇流出在调节血管新生中起着关键的作用. 研究者在小鼠离体主动脉和斑马鱼的血管新生实验中发现,AIBP和高密度脂蛋白（high density lipoprotein, HDL）协同调控胆固醇流出,抑制血管内皮生长因子（vascular endothelial growth factor,VEGF）刺激的血管新生.     

B Cells Regulate Neutrophilia during Mycobacterium tuberculosis Infection and BCG Vaccination by Modulating the Interleukin-17 Response

We have previously demonstrated that B cells can shape the immune response to Mycobacterium tuberculosis, including the level of neutrophil infiltration and granulomatous inflammation at the site of infection. The present study examined the mechanisms by which B cells regulate the host neutrophilic response upon exposure to mycobacteria and how neutrophilia may influence vaccine efficacy. To address these questions, a murine aerosol infection tuberculosis (TB) model and an intradermal (ID) ear BCG immunization mouse model, involving both the μMT strain and B cell-depleted C57BL/6 mice, were used. IL (interleukin)-17 neutralization and neutrophil depletion experiments using these systems provide evidence that B cells can regulate neutrophilia by modulating the IL-17 response during M. tuberculosis infection and BCG immunization. Exuberant neutrophilia at the site of immunization in B cell-deficient mice adversely affects dendritic cell (DC) migration to the draining lymph nodes and attenuates the development of the vaccine-induced Th1 response. The results suggest that B cells are required for the development of optimal protective anti-TB immunity upon BCG vaccination by regulating the IL-17/neutrophilic response. Administration of sera derived from M. tuberculosis-infected C57BL/6 wild-type mice reverses the lung neutrophilia phenotype in tuberculous μMT mice. Together, these observations provide insight into the mechanisms by which B cells and humoral immunity modulate vaccine-induced Th1 response and regulate neutrophila during M. tuberculosis infection and BCG immunization.     

Endémie bilharzienne à Schistosoma mansoni à la vallée du Kou : caractérisation du système de transmission et impact socioéconomique

Schistosomiasis is one of the waterborne diseases which benefit from environmental and behavioral changes induced by the mobilization of surface water resources in Sahelian countries, such as Burkina Faso. Studies have established the existence of human schistosomiasis in the Kou valley, one of the oldest hydro-agricultural zones in the country. However, the role of population behavior in the transmission pattern of this disease and its socioeconomic impact in this valley are poorly understood. It is in response to these questions that this study was undertaken. The objectives of this study were to identify activities that exposed most of the Valley's population to infection by schistosomiasis, and to contribute knowledge on the consequences of this disease. The study was conducted in the cold dry season at the Kou Valley, located in the South Sudanese area of Burkina Faso. It has adopted the strategy of direct observation to examine host–parasites interactions. The study of the socioeconomic consequences of the infection has been first to identify subjects that actually carry the parasite by screening the population by the Kato–Katz method. These were then subjected to a questionnaire. Data were analyzed using Epi Info 6.4. This work has revealed six activities at risk of infection for the residents of the Valley with an increased risk of factor for rice farming, household activities and swimming. In view of these activities, women and young people seem to be most vulnerable to infection. This disease causes significant economic losses as a function of socio-professional categories of infected persons.     

N-Acetylfarnesylcysteine is a novel class of peroxisome proliferator-activated receptor γ ligand with partial and full agonist activity in vitro and in vivo

The thiazolidedione (TZD) class of drugs is clinically approved for the treatment of type 2 diabetes. The therapeutic actions of TZDs are mediated via activation of peroxisome proliferator-activated receptor γ (PPARγ). Despite their widespread use, concern exists regarding the safety of currently used TZDs. This has prompted the development of selective PPARγ modulators (SPPARMs), compounds that promote glucose homeostasis but with reduced side effects due to partial PPARγ agonism. However, this also results in partial agonism with respect to PPARγ target genes promoting glucose homeostasis. Using a gene expression-based screening approach we identified N-acetylfarnesylcysteine (AFC) as both a full and partial agonist depending on the PPARγ target gene (differential SPPARM). AFC activated PPARγ as effectively as rosiglitazone with regard to Adrp, Angptl4, and AdipoQ, but was a partial agonist of aP2, a PPARγ target gene associated with increased adiposity. Induction of adipogenesis by AFC was also attenuated compared with rosiglitazone. Reporter, ligand binding assays, and dynamic modeling demonstrate that AFC binds and activates PPARγ in a unique manner compared with other PPARγ ligands. Importantly, treatment of mice with AFC improved glucose tolerance similar to rosiglitazone, but AFC did not promote weight gain to the same extent. Finally, AFC had effects on adipose tissue remodeling similar to those of rosiglitazone and had enhanced antiinflammatory effects. In conclusion, we describe a new approach for the identification of differential SPPARMs and have identified AFC as a novel class of PPARγ ligand with both full and partial agonist activity in vitro and in vivo.     

The role of electrical signals in murine corneal wound re-epithelialization

Ion flow from intact tissue into epithelial wound sites results in lateral electric currents that may represent a major driver of wound healing cell migration. Use of applied electric fields (EF) to promote wound healing is the basis of Medicare-approved electric stimulation therapy. This study investigated the roles for EFs in wound re-epithelialization, using the Pax6(+/-) mouse model of the human ocular surface abnormality aniridic keratopathy (in which wound healing and corneal epithelial cell migration are disrupted). Both wild-type (WT) and Pax6(+/-) corneal epithelial cells showed increased migration speeds in response to applied EFs in vitro. However, only Pax6(+/+) cells demonstrated consistent directional galvanotaxis towards the cathode, with activation of pSrc signaling, polarized to the leading edges of cells. In vivo, the epithelial wound site normally represents a cathode, but 43% of Pax6(+/-) corneas exhibited reversed endogenous wound-induced currents (the wound was an anode). These corneas healed at the same rate as WT. Surprisingly, epithelial migration did not correlate with direction or magnitude of endogenous currents for WT or mutant corneas. Furthermore, during healing in vivo, no polarization of pSrc was observed. We found little evidence that Src-dependent mechanisms of cell migration, observed in response to applied EFs in vitro, normally exist in vivo. It is concluded that endogenous EFs do not drive long-term directionality of sustained healing migration in this mouse corneal epithelial model. Ion flow from wounds may nevertheless represent an important component of wound signaling initiation.     

Lipases are soluble and active in glycerol carbonate as a novel biosolvent

Glycerol carbonate was synthesized as biosolvent for the development of soluble enzymatic system. The effects of various reaction parameters on activity and stability of lipases were investigated using the transesterification of ethyl butyrate with n-butanol as a model reaction. Enzymatic activity in glycerol carbonate was compared with that in water and in conventional organic solvents with different ionizing and dissociating abilities. The pK_a value of trichloroacetic acid and transesterification activities of Candida antarctica lipase B and Candida rugosa lipase in glycerol carbonate are similar to those in water, indicating that ionizing and dissociating powers are capable of satisfactorily predicting the biocompatibility of organic solvents for soluble enzymatic systems.     

FAM64A is an androgen receptor-regulated feedback tumor promoter in prostate cancer

Endocrine therapy for prostate cancer (PCa) mainly inhibits androgen receptor (AR) signaling, due to increased androgen synthesis and AR changes, PCa evolved into castration-resistant prostate cancer (CRPC). The function of Family With Sequence Similarity 64 Member A (FAM64A) and its association with prostate cancer has not been reported. In our research, we first reported that FAM64A is up-regulated and positively associated with poor prognosis of patients with prostate cancer (PCa) by TCGA database and immunohistochemistry staining. Moreover, knockdown of FAM64A significantly suppressed the proliferation, migration, invasion, and cell cycle of PCa cells in vitro. Mechanistically, FAM64A expression was increased by dihydrotestosterone (DHT) through direct binding of AR to FAM64A promoter, and notably promoted the proliferation, migration, invasion, and cell cycle of androgen-dependent cell line of PCa. In addition, abnormal expression of FAM64A affects the immune and interferon signaling pathway of PCa cells. In conclusion, FAM64A was up-regulated by AR through directly binding to its specific promoter region to promote the development of PCa, and was associated with the immune mechanism and interferon signaling pathway, which provided a better understanding and a new potential for treating PCa.Subject terms: Penile cancer, Predictive markers     

生物燃料系统分析模型

定量化系统分析模型是生物燃料潜力预测、影响分析及制定技术路线图和政策目标的重要工具。生物燃料供应链涉及很多行业,需要进行基于农 (林) 业、能源、经济和环境等多学科领域的综合分析。以下从生物燃料系统分析所需解决的问题出发,梳理了国内外生物燃料系统分析的一般方法,重点对农 (林) 业系统模型、能源系统模型、综合评价模型、微观成本、能耗和排放分析模型以及生物燃料专项宏观分析模型的主要优缺点和适用性进行了分析,给出了相应的应用实例,并强调根据特定的研究问题,选择具有不同适用性的模型和研究路线。有助于研究人员和政策制定者更好地了解生物燃料系统分析方法,也为我国学术研究机构建立生物燃料分析模型提供了参考。     

Transcriptional activation of endoplasmic reticulum chaperone GRP78 by HCMV IE1-72 protein

Glucose-regulated protein 78 (GRP78), a key regulator of endoplasmic reticulum (ER) stress, facilitates cancer cell growth and viral replication. The mechanism leading to grp78 gene activation during viral infection is largely unknown. In this study, we show that the immediate-early 1 (IE1-72) protein of the human cytomegalovirus (HCMV) is essential for HCMV-mediated GRP78 activation. IE1-72 upregulated grp78 gene expression depending on the ATP-binding site, the zinc-finger domain and the putative leucine-zipper motif of IE1-72, as well as the ER stress response elements (ERSEs) on the grp78 promoter. The purified IE1-72 protein bound to the CCAAT box within ERSE in vitro, whereas deletion mutants of IE1-72 deficient in grp78 promoter stimulation failed to do so. Moreover, IE1-72 binding to the grp78 promoter in infected cells accompanied the recruitment of TATA box-binding protein-associated factor 1 (TAF1), a histone acetyltransferase, and the increased level of acetylated histone H4, an indicator of active-state chromatin. These results provide evidence that HCMV IE1-72 activates grp78 gene expression through direct promoter binding and modulation of the local chromatin structure, indicating an active viral mechanism of cellular chaperone induction for viral growth.