Effect of membrane characteristics on phase separation and domain formation in cholesterol-lipid mixtures

We examine, using an analytical mean-field model, the distribution of cholesterol in a lipid bilayer. The model accounts for the perturbation of lipid packing induced by the embedded cholesterol, in a manner similar to that of transmembrane proteins. We find that the membrane-induced interactions between embedded cholesterol molecules vary as a function of the cholesterol content. Thus, the effective lipid-cholesterol interaction is concentration-dependent. Moreover, it transitions from repulsive to attractive to repulsive as the cholesterol content increases. As the concentration of cholesterol in the bilayer exceeds a critical value, phase separation occurs. The coexistence between cholesterol-rich and cholesterol-poor domains is universal for any bilayer parameters, although the composition of the cholesterol-rich phase varies as a function of the lipid properties. Although we do not assume specific cholesterol-lipid interactions or the formation of a lipid-cholesterol cluster, we find that the composition of the cholesterol-rich domains is constant, independent of the cholesterol content in the bilayer.     

Effects of anaesthetic agents in interference of naloxone-induced opiate-withdrawal are dose-dependent in opiate-dependent rats

In opiate-dependent rats previous studies showed that anaesthetic agents, such as chloral hydrate, midazolam and ketamine interfere with naloxone-precipitated opiate withdrawal. Each anaesthetic induces a specific pattern of interference, indicating that the interference is agent-dependent. In order to further investigate these effects and highlight a potential pharmacological basis of opiate withdrawal interference through anaesthetic agents, we hypothesized that anaesthetic-mediated interference of opiate withdrawal is also dose-dependent. Three groups of rats were compared in an experimental procedure of rapid withdrawal induction by an antagonist under anaesthesia using sub-anaesthetic dosage of midazolam, ketamine or saline. We observed that sub-anaesthetic dosage of ketamine, or midazolam, interferes significantly with opiate withdrawal expression. This brings arguments in favour of a pharmacological basis underlying rapid antagonists induction in opiate dependent rats.     

RNA-binding proteins in neurological diseases

Emerging studies support that RNA-binding proteins(RBPs)play critical roles in human biology and pathogenesis.RBPs are essential players in RNA processing and metabolism,including pre-mRNA splicing,polyadenylation,transport,surveillance,mRNA localization,mRNA stability control,translational control and editing of various types of RNAs.Aberrant expression of and mutations in RBP genes affect various steps of RNA processing,altering target gene function.RBPs have been associated with various diseases,including neurological diseases.Here,we mainly focus on selected RNA-binding proteins including Nova-1/Nova-2,HuR/HuB/HuC/HuD,TDP-43,Fus,Rbfox1/Rbfox2,QKI and FMRP,discussing their function and roles in human diseases.     

Distribution and characteristics of telocytes as nurse cells in the architectural organization of engineered heart tissues

Interstitial Cajal-like cells are a distinct type of interstitial cell with a wide distribution in mammalian organs and tissues,and have been given the name"telocytes".Recent studies have demonstrated the potential roles of telocytes in heart development,renewal,and repair.However,further research on the functions of telocytes is limited by the complicated in vivo environment.This study was designed to construct engineered heart tissue(EHT)as a three-dimensional model in vitro to better understand the role of telocytes in the architectural organization of the myocardium.EHTs were constructed by seeding neonatal cardiomyocytes in collagen/Matrigel scaffolds followed by culture under persistent static stretch.Telocytes in EHTs were identified by histology,toluidine blue staining,immunofluorescence,and transmission electron microscopy.The results from histology and toluidine blue staining demonstrated widespread putative telocytes with compact toluidine blue-stained nuclei,which were located around cardiomyocytes.Prolongations from the cell bodies showed a characteristic dichotomous branching pattern and formed networks in EHTs.Immunofluorescence revealed positive staining of telocytes for CD34 and vimentin with typical moniliform prolongations.A series of electron microscopy images further showed that typical telocytes embraced the cardiomyocytes with their long prolongations and exhibited a marked appearance of nursing cardiomyocytes during the construction of EHTs.This finding highlights the great importance of telocytes in the architectural organization of EHTs.It also suggests that EHT is an appropriate physical and pathological model system in vitro to study the roles of telocytes during heart development and regeneration.     

Inter-chain disulfide bond improved protein trans-splicing increases plasma coagulation activity in C57BL/6 mice following portal vein FVIII gene delivery by dual vectors

Protein trans-splicing based dual-vector factor VIII(FVIII) gene delivery is adversely affected by less efficiency of protein splicing.We sought to increase the amount of spliced FVIII protein and plasma coagulation activity in dual-vector FVIII transgene in mice by means of strengthening the interaction of inteins,protein splicing elements,thereby facilitating protein trans-splicing.Dual-vector delivery of the FVIII gene in cultured cells showed that replacement of Met226 in the heavy chain and Asp1828 in the light chain with Cys residues could facilitate inter-chain disulfide linking and improve protein trans-splicing,increasing the levels of spliced FVIII protein.In this study,C57BL/6 mice were coadministered dual vectors of intein-fused human FVIII heavy chain and light chain with Cys mutations via portal vein injection into the liver.Forty-eight hours post-injection,plasma was collected and analyzed for FVIII antigen concentration and coagulation activity.These mice showed increased circulating FVIII heavy chain polypeptide(442±151 ng mL-1 vs.305±103 ng mL-1) and coagulation activity(1.46±0.37 IU mL-1 vs.0.85±0.23 IU mL-1) compared with control mice co-administered dual vectors expressing the heavy and light chains of wild-type FVIII.Moreover,coagulation activity was similar to that of mice receiving a single vector expressing FVIII(1.79±0.59 IU mL-1).These findings indicate that improving protein trans-splicing by inter-chain disulfide bonding is a promising approach for increasing the efficacy of dual-vector based FVIII gene transfer.     

Comprehensive proteome analysis of malignant pleural effusion for lung cancer biomarker discovery by using multidimensional protein identification technology

Malignant pleural effusion (MPE) obtained from lung adenocarcinoma may contain potentially useful biomarkers for detection of lung cancer. In this study, we used a removal system for high-abundance proteins followed by one-dimensional SDS-PAGE combined with nano-LC-MS/MS to generate a comprehensive MPE proteome data set with 482 nonredundant proteins. Next, we integrated the MPE proteome and secretome data sets from three adenocarcinoma cell lines, with a view to identifying potential PE biomarkers originating from malignant cells. Four potential candidates, alpha-2-HS-glycoprotein (AHSG), angiogenin, cystatin-C, and insulin-like growth factor-binding protein 2, (IGFBP2), were isolated for preclinical validation using ELISA. Both AHSG and IGFBP2 levels were increased in lung patients with MPE (n = 68), compared to those with nonmalignant pleural effusion (n = 119). Notably, the IGFBP2 level was higher in MPE, compared with that in benign diseases (bacteria pneumonia and tuberculosis pleuritis), and significantly associated with malignancy, regardless of the cancer type. Our data additionally support an extracellular function of IGFBP2 in migration in lung cancer cells. These findings collectively suggest that the adenocarcinoma MPE proteome provides a useful data set for malignancy biomarker research.     

Screening for active small molecules in mitochondrial complex I deficient patient's fibroblasts, reveals AICAR as the most beneficial compound

Congenital deficiency of the mitochondrial respiratory chain complex I (CI) is a common defect of oxidative phosphorylation (OXPHOS). Despite major advances in the biochemical and molecular diagnostics and the deciphering of CI structure, function assembly and pathomechanism, there is currently no satisfactory cure for patients with mitochondrial complex I defects. Small molecules provide one feasible therapeutic option, however their use has not been systematically evaluated using a standardized experimental system. In order to evaluate potentially therapeutic compounds, we set up a relatively simple system measuring different parameters using only a small amount of patient's fibroblasts, in glucose free medium, where growth is highly OXPOS dependent. Ten different compounds were screened using fibroblasts derived from seven CI patients, harboring different mutations.5-Aminoimidazole-4-carboxamide ribotide (AICAR) was found to be the most beneficial compound improving growth and ATP content while decreasing ROS production. AICAR also increased mitochondrial biogenesis without altering mitochondrial membrane potential (Δψ). Fluorescence microscopy data supported increased mitochondrial biogenesis and activation of the AMP activated protein kinase (AMPK). Other compounds such as; bezafibrate and oltipraz were rated as favorable while polyphenolic phytochemicals (resverastrol, grape seed extract, genistein and epigallocatechin gallate) were found not significant or detrimental. Although the results have to be verified by more thorough investigation of additional OXPHOS parameters, preliminary rapid screening of potential therapeutic compounds in individual patient's fibroblasts could direct and advance personalized medical treatment.     

Solid state amorphization kinetic of alpha lactose upon mechanical milling

It has been previously reported that α-lactose could be totally amorphized by ball milling. In this paper we report a detailed investigation of the structural and microstructural changes by which this solid state amorphization takes place. The investigations have been performed by Powder X-ray Diffraction, Solid State Nuclear Magnetic Resonance (¹³C CP-MAS) and Differential Scanning Calorimetry. The results reveal the structural complexity of the material in the course of its amorphization so that it cannot be considered as a simple mixture made of a decreasing crystalline fraction and an increasing amorphous fraction. Heating this complexity can give rise to a fully nano-crystalline material. The results also show that chemical degradations upon heating are strongly connected to the melting process.     

Information engineering infrastructure for life sciences and its implementation in China

Biological data,represented by the data from omics platforms,are accumulating exponentially.As some other data-intensive scientific disciplines such as high-energy physics,climatology,meteorology,geology,geography and environmental sciences,modern life sciences have entered the information-rich era,the era of the 4th paradigm.The creation of Chinese information engineering infrastructure for pan-omics studies(CIEIPOS) has been long overdue as part of national scientific infrastructure,in accelerating the further development of Chinese life sciences,and translating rich data into knowledge and medical applications.By gathering facts of current status of international and Chinese bioinformatics communities in collecting,managing and utilizing biological data,the essay stresses the significance and urgency to create a ’data hub’ in CIEIPOS,discusses challenges and possible solutions to integrate,query and visualize these data.Another important component of CIEIPOS,which is not part of traditional biological data centers such as NCBI and EBI,is omics informatics.Mass spectroscopy platform was taken as an example to illustrate the complexity of omics informatics.Its heavy dependency on computational power is highlighted.The demand for such power in omics studies is argued as the fundamental function to meet for CIEIPOS.Implementation outlook of CIEIPOS in hardware and network is discussed.