Electrophoretic Deposition (EPD) of Lectin in the Presence of New Glycopolymers Aiming at Facile Detection of Carbohydrate–Protein Interactions

Atom transfer radical polymerization of allyl methacrylate followed by a thiol‐ene click reaction with 1‐thio‐β‐D‐glucose tetraacetate is performed to afford a new type of glycopolymers via deacetylation. Their interactions with a sugar‐binding protein are evaluated by electrophoretic deposition (EPD) procedures as well as fluorescence measurements. The deposition amount of concanavalin A (conA) in the presence of glucose or galactose measured by EPD is remarkably different from that in the presence of the synthesized glycopolymer, even though the concentration of sugar residue is the same. The deposition amount, as well as the electric current that flows during the EPD, is higher in the presence of the polymer, which confirms that interaction of conA with the glycopolymer is detected by the EPD procedure.     

Glycopolymer Polyelectrolyte Multilayers Composed of Heparin and Maltose‐Modified Poly(ethylene imine) as a Strong/Weak Polyelectrolyte System for Future Drug Delivery Coatings: Influence of pH and Sugar Architecture on Growth of Multilayers and Multilayer Swelling and Stability

Establishing highly sophisticated polymer films for delivery systems in a biological environment and bioanalytical tasks, the formation, thickness, swelling behavior, and (physiological) stability of highly biocompatible polyelectrolyte multilayers (PEMs) are described. These PEMs are composed of the very weak polycation maltose‐modified hyperbranched poly(ethylene imine) (PEI‐Mal) and the strong polyanion heparin sodium salt (HE^?Na⁺) deposited on Si wafer substrates . Two different glyco architectures for PEI‐Mal are used, characterized by two different degrees of maltose decoration on a PEI scaffold. Using two pH‐dependent deposition approaches for optimizing the (physiological) PEM stability and swelling, PEMs are characterized by (in situ) ellipsometry, atomic force microscopy (AFM), and (in situ) attenuated total reflection‐Fourier‐transform infrared (ATR‐FTIR). Thus, PEMs reveal significantly different thicknesses, growth mechanisms (linear versus exponential), and swelling behavior in dependence of both the polycation architectures and the deposition protocol. These PEMs will allow the study of their complexation and release properties as preswollen PEMs against anionic drug molecules, especially under physiological conditions in the future.

     

Microbiota and host immune responses: a love–hate relationship

A complex relationship between the microbiota and the host emerges early at birth and continues throughout life. The microbiota includes the prokaryotes, viruses and eukaryotes living among us, all of which interact to different extents with various organs and tissues in the body, including the immune system. Although the microbiota is most dense in the lower intestine, its influence on host immunity extends beyond the gastrointestinal tract. These interactions with the immune system operate through the actions of various microbial structures and metabolites, with outcomes ranging from beneficial to deleterious for the host. These differential outcomes are dictated by host factors, environment, and the type of microbes or products present in a specific ecosystem. It is also becoming clear that the microbes are in turn affected and respond to the host immune system. Disruption of this complex dialogue between host and microbiota can lead to immune pathologies such as inflammatory bowel diseases, diabetes and obesity. This review will discuss recent advances regarding the ways in which the host immune system and microbiota interact and communicate with one another.     

Intestinal microbiota and faecal transplantation as treatment modality for insulin resistance and type 2 diabetes mellitus

The prevalence of obesity and diabetes mellitus type 2 is increasing rapidly around the globe. Recent insights have generated an entirely new perspective that the intestinal microbiota may play a significant role in the development of these metabolic disorders. Alterations in the intestinal microbiota composition promote systemic inflammation that is a hallmark of obesity and subsequent insulin resistance. Thus, it is important to understand the reciprocal relationship between intestinal microbiota composition and metabolic health in order to eventually prevent disease progression. In this respect, faecal transplantation studies have implicated that butyrate‐producing intestinal bacteria are crucial in this process and be considered as key players in regulating diverse signalling cascades associated with human glucose and lipid metabolism.     

HIV-exposed uninfected children: a growing population with a vulnerable immune system?

Through the successful implementation of policies to prevent mother-to-child-transmission (PMTCT) of HIV-1 infection, children born to HIV-1-infected mothers are now much less likely to acquire HIV-1 infection than previously. Nevertheless, HIV-1-exposed uninfected (HEU) children have substantially increased morbidity and mortality compared with children born to uninfected mothers (unexposed uninfected, UU), predominantly from infectious causes. Moreover, a range of phenotypical and functional immunological differences between HEU and UU children has been reported. As the number of HEU children continues to increase worldwide, two questions with clear public health importance need to be addressed: first, does exposure to HIV-1 and/or ART in utero or during infancy have direct immunological consequences, or are these poor outcomes simply attributable to the obvious disadvantages of being born into an HIV-affected household? Secondly, can we expect improved maternal care and ART regimens during and after pregnancy, together with optimized infant immunization schedules, to reduce the excess morbidity and mortality of HEU children?     

Renal Agenesis in Kallmann Syndrome: A Network Approach

Kallmann syndrome (KS) is defined by the combination of isolated hypogonadotrophic hypogonadism (IHH) and anosmia, with renal agenesis occurring in 30% of KS cases with KAL1 gene mutations. Unlike other KS‐related disorders, renal agenesis cannot be directly associated with mutations in the KAL1 gene. We hypothesized that protein interaction networks may suggest a link between genes currently known to be associated with KS on the one hand and those associated with renal agenesis on the other hand. We created a STRING protein interaction network from KS‐related genes and renal‐agenesis‐associated genes and analyzed it with Cytoscape 3.0.1 network software. The STRING protein interaction network provided a conceptual framework for current knowledge on the subject of renal morphogenesis in Kallmann syndrome. In addition, STRING and Cytoscape 3.0.1 software identified new potential KS renal‐aplasia‐associated genes (PAX2, BMP4, and SOX10). The use of protein–protein interaction networks and network analysis tools provided interesting insights and possible directions for future studies on the subject of renal aplasia in Kallmann syndrome.     

Fasciola hepatica tegumental antigens induce anergic‐like T cells via dendritic cells in a mannose receptor‐dependent manner

FoxP3⁺ Treg cells and anergic T cells are the two regulatory phenotypes of T‐cell responses associated with helminth infection. Here, we examine the T‐cell responses in mice during Fasciola hepatica infection, and to its tegumental coat antigens (FhTeg) that are shed from the fluke every 2–3 h. FhTeg comprises a rich source of glycoproteins, mainly oligomannose N‐glycans that bind to mannose receptor. This study demonstrated a novel mechanism for the T‐cell unresponsiveness observed during F. hepatica infection and after injection with FhTeg. Markers of T‐cell anergy, such as GRAIL, EGR2, ICOS, and ITCH, are enhanced amongst CD4⁺ T‐cell populations during infection and following FhTeg injection. This is characterized by a lack of cytokine responses and reduced proliferative activity, which can be reversed with the addition of IL‐2. FhTeg‐activated dendritic cells (DCs) suppress T cells in vitro as measured by enhanced GRAIL and CTLA4 by RNA and suppressed cytokine expression in anti‐CD3 stimulated CD4⁺ T cells. FhTeg‐treated DCs have enhanced MR expression, which is critical for DC‐CD4⁺ T‐cell communication. Taken together, this study presents markers of anergy in a mouse model of F. hepatica infection, and improves our understanding of host–pathogen interactions and how helminths modulate host immunity.     

Auditory input modulates sleep: an intra‐cochlear‐implanted human model

To properly demonstrate the effect of auditory input on sleep of intra‐cochlear‐implanted patients, the following approach was developed. Four implanted deaf patients were recorded during four nights: two nights with the implant OFF, with no auditory input, and two nights with the implant ON, that is, with normal auditory input, being only the common night sounds present, without any additional auditory stimuli delivered. The sleep patterns of another five deaf people were used as controls, exhibiting normal sleep organization. Moreover, the four experimental patients with intra‐cochlear devices and the implant OFF also showed normal sleep patterns. On comparison of the night recordings with the implant ON and OFF, a new sleep organization was observed for the recordings with the implant ON, suggesting that brain plasticity may produce changes in the sleep stage percentages while maintaining the ultradian rhythm. During sleep with the implant ON, the analysis of the electroencephalographic delta, theta and alpha bands in the frequency domain, using the Fast Fourier Transform, revealed a diversity of changes in the power originated in the contralateral cortical temporal region. Different power shifts were observed, perhaps related to the exact position of the implant inside the cochlea and the scalp electrode location. In conclusion, this pilot study shows that the auditory input in humans can introduce changes in central nervous system activity leading to shifts in sleep characteristics, as previously demonstrated in guinea pigs. We are postulating that an intra‐cochlear‐implanted deaf patient may have a better recovery if the implant is maintained ON during the night, that is, during sleep.     

Understanding the Mechanism of Anomalous Viscosity–Molecular Weight Relationships of Diolic Perfluoropoly (Oxyethylene‐ran‐oxymethylene): What is Missing in the Debye–Bueche Model?

For decades, the viscosity (η)–molecular weight (M) relationship of linear polymer melts has been successfully described by the Debye–Bueche model when M is lower than critical molecular weight (Mc). However, recent studies on diolic perfluoropoly (oxyethylene‐ran‐oxymethylene) (DPFPO), a linear polymer with polar endgroups, raise uncertainty on the validity of Debye–Bueche model. Experimental results show that the Debye–Bueche model does not hold for DPFPO, which has been attributed to the fact that the strong intermolecular endgroup–endgroup coupling is not considered in original Debye–Bueche model. A modified molecular‐level model, in which the endgroup–endgroup coupling is taken into consideration, is proposed to interpret the anomalous η–M relationship of DPFPO.     

Using biological knowledge to uncover the mystery in the search for epistasis in genome-wide association studies

The search for the missing heritability in genome-wide association studies (GWAS) has become an important focus for the human genetics community. One suspected location of these genetic effects is in gene-gene interactions, or epistasis. The computational burden of exploring gene-gene interactions in the wealth of data generated in GWAS, along with small to moderate sample sizes, have led to epistasis being an afterthought, rather than a primary focus of GWAS analyses. In this review, I discuss some potential approaches to filter a GWAS dataset to a smaller, more manageable dataset where searching for epistasis is considerably more feasible. I describe a number of alternative approaches, but primarily focus on the use of prior biological knowledge from databases in the public domain to guide the search for epistasis. The manner in which prior knowledge is incorporated into a GWA study can be many and these data can be extracted from a variety of database sources. I discuss a number of these approaches and propose that a comprehensive approach will likely be most fruitful for searching for epistasis in large-scale genomic studies of the current state-of-the-art and into the future.     

Regulation of immune cell signaling by SHIP1: A phosphatase,scaffold protein,and potential therapeutic target

The phosphoinositide phosphatase SHIP is a critical regulator of immune cell activation. Despite considerable study, the mechanisms controlling SHIP activity to ensure balanced cell activation remain incompletely understood. SHIP dampens BCR signaling in part through its association with the inhibitory coreceptor Fc gamma receptor IIB, and serves as an effector for other inhibitory receptors in various immune cell types. The established paradigm emphasizes SHIP's inhibitory receptor‐dependent function in regulating phosphoinositide 3‐kinase signaling by dephosphorylating the phosphoinositide PI(3,4,5)P₃; however, substantial evidence indicates that SHIP can be activated independently of inhibitory receptors and can function as an intrinsic brake on activation signaling. Here, we integrate historical and recent reports addressing the regulation and function of SHIP in immune cells, which together indicate that SHIP acts as a multifunctional protein controlled by multiple regulatory inputs, and influences downstream signaling via both phosphatase‐dependent and ‐independent means. We further summarize accumulated evidence regarding the functions of SHIP in B cells, T cells, NK cells, dendritic cells, mast cells, and macrophages, and data suggesting defective expression or activity of SHIP in autoimmune and malignant disorders. Lastly, we discuss the biological activities, therapeutic promise, and limitations of small molecule modulators of SHIP enzymatic activity.     

Defining short and long sleep duration for future paediatric research: A systematic literature review

Short and long sleep patterns in children have been associated with a range of poor health outcomes. However, there is no consensus regarding the definitions of these abnormal sleep parameters in childhood for use in paediatric research. Given that there is a clear lack of definitions for sleep duration throughout paediatric sleep literature, this review aimed to establish recommendations for standard cut‐offs of short and long sleep for children aged 1–16 years to enable homogeneity in future studies of paediatric sleep duration. Four databases were systematically searched to identify prospective studies that defined short or long sleep patterns in children. Included papers (38) were assessed for methodological quality, and their definitions were extracted to examine the current applied cut‐offs in the literature for short or long sleep duration. The definitions were analysed in a regression model to summarize applied cut‐offs from subjective data into cut‐offs for short and long sleep duration. These models were fitted to reference values of three commonly cited paediatric population studies to establish new definitions of sleep duration for future use in research. Across the age groups there was little consensus in applied cut‐offs for short and long sleep duration. This study found the best compromise for short sleep was defined as the 2.5th centile (hours = 0.25*age + 11) and long sleep as the 97.5th centile (hours = 0.017*age² ? 0.68*age + 16) of sleep duration in children. Recommendations for the hourly cut‐offs of short and long sleep duration based on these percentiles were described.     

Redox and pH Dual‐Responsive Supramolecular Micelles with a Traditional Polymer Block and a Supramolecular Block for Drug Controlled Release

Redox and pH dual‐responsive supramolecular micelles are prepared through a traditional polymer block and a supramolecular block to completely release the drugs. Ferrocene‐introduced and hydrophobic‐modified β‐cyclodextrin (β‐CD‐Fc‐Ace, where β‐CD, Fc, and Ace refer to β‐cyclodextrin, ferrocene, and acetal, respectively) is used to build the supramolecular block. Adamantane‐terminated poly(ethylene glycol) methyl ether (mPEG‐Ada) is the traditional polymer block. The average diameter of supramolecular micelles is ≈100 nm. Supramolecular micelles are able to control the release of the drugs in the cancer cells due to pH and redox microenvironments.

     

A potentially dynamic lysosomal role for the endogenous TRPML proteins

Lysosomal storage disorders (LSDs) constitute a diverse group of inherited diseases that result from lysosomal storage of compounds occurring in direct consequence to deficiencies of proteins implicated in proper lysosomal function. Pathology in the LSD mucolipidosis type IV (MLIV), is characterized by lysosomal storage of lipids together with water‐soluble materials in cells from every tissue and organ of affected patients. Mutations in the mucolipin 1 (TRPML1) protein cause MLIV and TRPML1 has also been shown to interact with two of its paralogous proteins, mucolipin 2 (TRPML2) and mucolipin 3 (TRPML3), in heterologous expression systems. Heterogeneous lysosomal storage is readily identified in electron micrographs of MLIV patient cells, suggesting that proper TRPML1 function is essential for the maintenance of lysosomal integrity. In order to investigate whether TRPML2 and TRPML3 also play a role in the maintenance of lysosomal integrity, we conducted gene‐specific knockdown assays against these protein targets. Ultrastructural analysis revealed lysosomal inclusions in both TRPML2 and TRPML3 knockdown cells, suggestive of a common mechanism for these proteins, in parallel with TRPML1, in the regulation of lysosomal integrity. However, co‐immunoprecipitation assays revealed that physical interactions between each of the endogenous TRPML proteins are quite limited. In addition, we found that all three endogenous proteins only partially co‐localize with each other in lysosomal as well as extra‐lysosomal compartments. This suggests that native TRPML2 and TRPML3 might participate with native TRPML1 in a dynamic form of lysosomal regulation. Given that depletion of TRPML2/3 led to lysosomal storage typical to an LSD, we propose that depletion of these proteins might also underlie novel LSD pathologies not described hitherto. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

GSTP1 is a hub gene for gene–air pollution interactions on childhood asthma

There is growing evidence that multiple genes and air pollutants are associated with asthma. By identifying the effect of air pollution on the general population, the effects of air pollution on childhood asthma can be better understood. We conducted the Taiwan Children Health Study (TCHS) to investigate the influence of gene–air pollution interactions on childhood asthma. Complete monitoring data for the ambient air pollutants were collected from Taiwan Environmental Protection Agency air monitoring stations. Our results show a significant two‐way gene–air pollution interaction between glutathione S‐transferase P (GSTP1) and PM₁₀ on the risk of childhood asthma. Interactions between GSTP1 and different types of air pollutants have a higher information gain than other gene–air pollutant combinations. Our study suggests that interaction between GSTP1 and PM₁₀ is the most influential gene–air pollution interaction model on childhood asthma. The different types of air pollution combined with the GSTP1 gene may alter the susceptibility to childhood asthma. It implies that GSTP1 is an important hub gene in the anti‐oxidative pathway that buffers the harmful effects of air pollution.     

Accurate Targeting and Controllable Release of Hybrid Liposome Containing a Stretchable Copolymer

Developing an intelligent drug delivery/release system, which can transport drugs to the target tissues precisely and release drugs timely, is an important challenge in chemotherapy. A multistage sensitive drug delivery system is designed by inserting a folate (FA) modified lipid and a pH/temperature dual‐sensitive amphiphilic copolymer into a liposome bilayer. The stretchable copolymer plays a role in protection on FA ligand for more accurate targeting. Then, the stretch ability of the copolymer in the liposome bilayer is verified by using the Langmuir–Blodgett film technique. The interaction between the 1,2‐dipalmitoyl‐sn‐glycerol‐3‐phosphocholine (DPPC) monolayer and hybrid liposomes is found to increase, indicating the FA ligand is exposed due to the copolymer shrinking with increasing temperature. Fluorescence polarization measurements demonstrate that the insertion of the copolymer improves the stability of the liposome and offers pH‐controllability for drug release. As a result, the drug leakage of the hybrid liposome is restrained significantly at pH 7.4, while at an acidic pH, the drug release is accelerated. The designed pH/temperature dual‐sensitive copolymer is expected to provide more precise targeting and environmentally controlled drug release to drug delivery systems based on liposomes.     

Clinical and genetic characterization of Bardet–Biedl syndrome in Tunisia: defining a strategy for molecular diagnosis

Bardet–Biedl syndrome (BBS, OMIM 209900) is a rare genetic disorder characterized by obesity, retinitis pigmentosa, post axial polydactyly, cognitive impairment, renal anomalies and hypogonadism. The aim of this study is to provide a comprehensive clinical and molecular analysis of a cohort of 11 Tunisian BBS consanguineous families in order to give insight into clinical and genetic spectrum and the genotype–phenotype correlations. Molecular analysis using combined sequence capture and high‐throughput sequencing of 30 ciliopathies genes revealed 11 mutations in 11 studied families. Five mutations were novel and six were previously described. Novel mutations included c.1110G>A and c.39delA (p.G13fs*41) in BBS1, c.115+5G>A in BBS2, c.1272+1G>A in BBS6, c.1181_1182insGCATTTATACC in BBS10 (p.S396Lfs*6). Described mutations included c.436C>T (p.R146*) and c.1473+4A>G in BBS1, c.565C> (p.R189*) in BBS2, deletion of exons 4–6 in BBS4, c.149T>G (p.L50R) in BBS5, and c.459+1G>A in BBS8; most frequent mutations were described in BBS1 (4/11, 37%) and BBS2 (2/11, 18%) genes. No phenotype–genotype correlation was evidenced. This data expands the mutations profile of BBS genes in Tunisia and suggests a divergence of the genetic spectrum comparing Tunisian and other populations.