Inhalable neutralizing antibodies – promising approach to combating respiratory viral infections

Monoclonal antibodies represent an exciting class of therapeutics against respiratory viral infections. Notwithstanding their specificity and affinity, the conventional parenteral administration is suboptimal in delivering antibodies for neutralizing activity in the airways due to the poor distribution of macromolecules to the respiratory tract. Inhaled therapy is a promising approach to overcome this hurdle in a noninvasive manner, while advances in antibody engineering have led to the development of unique antibody formats which exhibit properties desirable for inhalation. In this Opinion, we examine the major challenges surrounding the development of inhaled antibodies, identify knowledge gaps that need to be addressed and provide strategies from a drug delivery perspective to enhance the efficacy and safety of neutralizing antibodies against respiratory viral infections

UBR2 of the N-end rule pathway is required for chromosome stability via histone ubiquitylation in spermatocytes and somatic cells

The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells. © 2012 Kwon et al

Transplantation of Photoreceptor Precursors Isolated via a Cell Surface Biomarker Panel From Embryonic Stem Cell-Derived Self-Forming Retina.

Loss of photoreceptors due to retinal degeneration is a major cause of untreatable blindness. Cell replacement therapy, using pluripotent stem cell-derived photoreceptor cells, may be a feasible future treatment. Achieving safe and effective cell replacement is critically dependent on the stringent selection and purification of optimal cells for transplantation. Previously, we demonstrated effective transplantation of post-mitotic photoreceptor precursor cells labelled by fluorescent reporter genes. As genetically labelled cells are not desirable for therapy, here we developed a surface biomarker cell selection strategy for application to complex pluripotent stem cell differentiation cultures. We show that a five cell surface biomarker panel CD73(+)CD24(+)CD133(+)CD47(+)CD15(-) facilitates the isolation of photoreceptor precursors from three-dimensional self-forming retina differentiated from mouse embryonic stem cells. Importantly, stem cell-derived cells isolated using the biomarker panel successfully integrate and mature into new rod photoreceptors in the adult mouse retinae after subretinal transplantation. Conversely, unsorted or negatively selected cells do not give rise to newly integrated rods after transplantation. The biomarker panel also removes detrimental proliferating cells prior to transplantation. Notably, we demonstrate how expression of the biomarker panel is conserved in the human retina and propose that a similar selection strategy will facilitate isolation of human transplantation-competent cells for therapeutic application. Stem Cells 2015;33:2469-2482

Porphyromonas gingivalis suppresses adaptive immunity in periodontitis, atherosclerosis and Alzheimer’s disease

Porphyromonas gingivalis, a keystone pathogen in chronic periodontitis, has been found to associate with remote body organ inflammatory pathologies including atherosclerosis and Alzheimer’s disease (AD). Although P. gingivalis has a plethora of virulence factors, much of its pathogenicity is surprisingly related to the overall immunosuppression of the host. This review focuses on P. gingivalis aiding suppression of the host’s adaptive immune system involving manipulation of cellular immunological responses specifically T- and B-cells in periodontitis and related conditions. In periodontitis this bacterium inhibits the synthesis of IL-2 and increases humoral responses. This reduces inflammatory responses related to T- and B-cell activation, and subsequent IFN-ɤ secretion by a subset of T cells. The T cells further suppresses upregulation of programmed cell death-1 (PD-1)-receptor on CD+-cells and its ligand PD-L1 on CD11b+- subset of T-cells. IL-2 down-regulates immune response-regulated genes, induces a cytokine pattern in which the Th17 lineage is favored thereby modulating the Th17/ T-regulatory cell (Treg) imbalance. The suppression of IFN-ɤ stimulated release of interferon-inducible protein-10 (IP-10) chemokine ligands [ITAC (CXCL11) and Mig (CXCL9)] by P. gingivalis capsular serotypes, triggers distinct T-cell responses, and contributes to local immune evasion by release of its outer membrane vesicles. In atherosclerosis P. gingivalis reduces Tregs and transforming growth factor beta-1 (TGF-1) and causes imbalance in the Th17 lineage of the Treg population. In Alzheimer’s disease P. gingivalis may affect the blood-brain barrier permeability, and inhibit local IFN-ɤ response by preventing entry of immune cells into the brain. The scarcity of adaptive immune cells in Alzheimer’s disease neuropathology implies P. gingivalis infection of the brain likely causes impaired clearance of insoluble amyloid and induces immunosuppression. By the effective manipulation of the armory of adaptive immune suppression through a plethora of virulence factors P. gingivalis may act as a keystone organism in periodontitis and in related systemic diseases and other remote body inflammatory pathologies

Impact of Inpatient Care in Emergency Department on Outcomes: A Quasi-Experimental Cohort Study

BACKGROUND: Hospitals around the world are faced with the issue of boarders in emergency department (ED), patients marked for admission but with no available inpatient bed. Boarder status is known to be associated with delayed inpatient care and suboptimal outcomes. A new care delivery system was developed in our institution where boarders received full inpatient care from a designated medical team, acute medical team (AMT), while still residing at ED. The current study examines the impact of this AMT intervention on patient outcomes. METHODS: We conducted a retrospective quasi-experimental cohort study to analyze outcomes between the AMT intervention and conventional care in a 1250-bed acute care tertiary academic hospital in Singapore. Study participants included patients who received care from the AMT, a matched cohort of patients admitted directly to inpatient wards (non-AMT) and a sample of patients prior to the intervention (pre-AMT group). Primary outcomes were length of hospital stay (LOS), early discharges (within 24 h) and bed placement. Secondary outcomes included unplanned readmissions within 3 months, and patient’s bill size. χ2- and Mann-Whitney U tests were used to test for differences between the cohorts on dichotomous and continuous variables respectively. RESULTS: The sample comprised of 2279 patients (1092 in AMT, 1027 in non-AMT, and 160 in pre-AMT groups). Higher rates of early discharge (without significant differences in the readmission rates) and shorter LOS were noted for the AMT patients. They were also more likely to be admitted into a ward allocated to their discipline and had lower bill size compared to non AMT patients. CONCLUSIONS: The AMT intervention improved patient outcomes and resource utilization. This model was noted to be sustainable and provides a potential solution for hospitals’ ED boarders who face a gap in inpatient care during their crucial first few hours of admissions while waiting for an inpatient bed

Waterproof Flexible InP@ZnSeS Quantum Dot Light-Emitting Diode

The development of flexible displays for wearable electronics applications has created demand for high-performance quantum dot (QD) light-emitting diodes (QLEDs) based on QD core@shell structures. Emerging indium phosphide (InP)-based core@shell QDs show promise as lighting material in the field of optoelectronics because they are environmentally friendly material, can be produced in a cost-effective manner, and are capable of tunable emission. While efforts have been made to enhance the performance of InP-based QLED, the stabilities of InP@ZnSeS QDs film and InP@ZnSeS-based QLED in water/air are not yet fully understood, limiting their practical applications. Herein, a highly durable, flexible InP@ZnSeS QLED encapsulated in an ultrathin film of CYTOP, a solution-based amorphous fluoropolymer, is demonstrated. The CYTOP-encapsulated green flexible QLED shows an external quantum efficiency (EQE) of 0.904% and a high luminescence of 1593 cd/m2 as well as outstanding waterproof performance. The flexible device emits strong luminescence after being immersed in water for ~20 minutes. Even when subjected to continuous tensile stress with a 5 mm bending radius, the high luminescence is preserved. This waterproof architecture can be a promising strategy for wearable electronics applications

Performance of Monolayer Graphene Nanomechanical Resonators with Electrical Readout

The enormous stiffness and low density of graphene make it an ideal material for nanoelectromechanical (NEMS) applications. We demonstrate fabrication and electrical readout of monolayer graphene resonators, and test their response to changes in mass and temperature. The devices show resonances in the MHz range. The strong dependence of the resonant frequency on applied gate voltage can be fit to a membrane model, which yields the mass density and built-in strain. Upon removal and addition of mass, we observe changes in both the density and the strain, indicating that adsorbates impart tension to the graphene. Upon cooling, the frequency increases; the shift rate can be used to measure the unusual negative thermal expansion coefficient of graphene. The quality factor increases with decreasing temperature, reaching ~10,000 at 5 K. By establishing many of the basic attributes of monolayer graphene resonators, these studies lay the groundwork for applications, including high-sensitivity mass detectors

UBR2 of the N-End Rule Pathway Is Required for Chromosome Stability via Histone Ubiquitylation in Spermatocytes and Somatic Cells

The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells