ENGINEERING GENE EDITORS FOR IN VIVO THERAPEUTICS

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Photo-Attachment of Biomolecules for Miniaturization on Wicking Si-Nanowire Platform

We demonstrated the surface functionalization of a highly three-dimensional, superhydrophilic wicking substrate using light to immobilize functional biomolecules for sensor or microarray applications. We showed here that the three-dimensional substrate was compatible with photo-attachment and the performance of functionalization was greatly improved due to both increased surface capacity and reduced substrate reflectivity. In addition, photo-attachment circumvents the problems induced by wicking effect that was typically encountered on superhydrophilic three-dimensional substrates, thus reducing the difficulty of producing miniaturized sites on such substrate. We have investigated various aspects of photo-attachment process on the nanowire substrate, including the role of different buffers, the effect of wavelength as well as how changing probe structure may affect the functionalization process. We demonstrated that substrate fabrication and functionalization can be achieved with processes compatible with microelectronics processes, hence reducing the cost of array fabrication. Such functionalization method coupled with the high capacity surface makes the substrate an ideal candidate for sensor or microarray for sensitive detection of target analytes.National University of Singapore (Graduate School for Integrative Sciences and Engineering scholarship)GLOBALFOUNDRIES Singapore Pte. Ltd.Singapore-MIT Allianc

TRPV4-Mediated Calcium Influx into Human Bronchial Epithelia upon Exposure to Diesel Exhaust Particles

BACKGROUND: Human respiratory epithelia function in airway mucociliary clearance and barrier function and have recently been implicated in sensory functions. OBJECTIVE: We investigated a link between chronic obstructive pulmonary disease (COPD) pathogenesis and molecular mechanisms underlying Ca2+ influx into human airway epithelia elicited by diesel exhaust particles (DEP). METHODS AND RESULTS: Using primary cultures of human respiratory epithelial (HRE) cells, we determined that these cells possess proteolytic signaling machinery, whereby proteinase-activated receptor-2 (PAR-2) activates Ca2+-permeable TRPV4, which leads to activation of human respiratory disease-enhancing matrix metalloproteinase-1 (MMP-1), a signaling cascade initiated by diesel exhaust particles (DEP), a globally relevant air pollutant. Moreover, we observed ciliary expression of PAR-2, TRPV4, and phospholipase-Cβ3 in human airway epithelia and their DEP-enhanced protein-protein complex formation. We also found that the chronic obstructive pulmonary disease (COPD)-predisposing TRPV4P19S variant enhances Ca2+ influx and MMP 1 activation, providing mechanistic linkage between man-made air pollution and human airway disease. CONCLUSION: DEP evoked protracted Ca2+ influx via TRPV4, enhanced by the COPD-predisposing human genetic polymorphism TRPV4P19S. This mechanism reprograms maladaptive inflammatory and extracellular-matrix-remodeling responses in human airways. The novel concept of air pollution-responsive ciliary signal transduction from PAR-2 to TRPV4 in human respiratory epithelia will accelerate rationally targeted therapies, possibly via the inhalatory route

Atrasentan and renal events in patients with type 2 diabetes and chronic kidney disease (SONAR): a double-blind, randomised, placebo-controlled trial

Background: Short-term treatment for people with type 2 diabetes using a low dose of the selective endothelin A receptor antagonist atrasentan reduces albuminuria without causing significant sodium retention. We report the long-term effects of treatment with atrasentan on major renal outcomes. Methods: We did this double-blind, randomised, placebo-controlled trial at 689 sites in 41 countries. We enrolled adults aged 18–85 years with type 2 diabetes, estimated glomerular filtration rate (eGFR)25–75 mL/min per 1·73 m 2 of body surface area, and a urine albumin-to-creatinine ratio (UACR)of 300–5000 mg/g who had received maximum labelled or tolerated renin–angiotensin system inhibition for at least 4 weeks. Participants were given atrasentan 0·75 mg orally daily during an enrichment period before random group assignment. Those with a UACR decrease of at least 30% with no substantial fluid retention during the enrichment period (responders)were included in the double-blind treatment period. Responders were randomly assigned to receive either atrasentan 0·75 mg orally daily or placebo. All patients and investigators were masked to treatment assignment. The primary endpoint was a composite of doubling of serum creatinine (sustained for ≥30 days)or end-stage kidney disease (eGFR <15 mL/min per 1·73 m 2 sustained for ≥90 days, chronic dialysis for ≥90 days, kidney transplantation, or death from kidney failure)in the intention-to-treat population of all responders. Safety was assessed in all patients who received at least one dose of their assigned study treatment. The study is registered with ClinicalTrials.gov, number NCT01858532. Findings: Between May 17, 2013, and July 13, 2017, 11 087 patients were screened; 5117 entered the enrichment period, and 4711 completed the enrichment period. Of these, 2648 patients were responders and were randomly assigned to the atrasentan group (n=1325)or placebo group (n=1323). Median follow-up was 2·2 years (IQR 1·4–2·9). 79 (6·0%)of 1325 patients in the atrasentan group and 105 (7·9%)of 1323 in the placebo group had a primary composite renal endpoint event (hazard ratio [HR]0·65 [95% CI 0·49–0·88]; p=0·0047). Fluid retention and anaemia adverse events, which have been previously attributed to endothelin receptor antagonists, were more frequent in the atrasentan group than in the placebo group. Hospital admission for heart failure occurred in 47 (3·5%)of 1325 patients in the atrasentan group and 34 (2·6%)of 1323 patients in the placebo group (HR 1·33 [95% CI 0·85–2·07]; p=0·208). 58 (4·4%)patients in the atrasentan group and 52 (3·9%)in the placebo group died (HR 1·09 [95% CI 0·75–1·59]; p=0·65). Interpretation: Atrasentan reduced the risk of renal events in patients with diabetes and chronic kidney disease who were selected to optimise efficacy and safety. These data support a potential role for selective endothelin receptor antagonists in protecting renal function in patients with type 2 diabetes at high risk of developing end-stage kidney disease. Funding: AbbVie

Postnatal Genome Editing With CRISPR

Targeted genome editing holds tremendous promise for permanent correction of many genetic diseases. The recently developed CRISPR/Cas9 genome-editing tool exhibits facile programmability and robust gene-editing efficiency, and has been applied in cell cultures and animal tissues. However, multi-organ gene-editing in live mammals has not been examined or achieved. This study demonstrates genetic modification in multiple organs of postnatal mice by systemic delivery of CRISPR with adeno-associated viruses (AAVs). I resolved the AAV payload limitation by splitting Cas9 and reconstituting the native protein in vivo using scarless split-intein protein trans-splicing, which preserves full activity of Cas9. I determined that the delivery efficiency of AAV-CRISPR dictates gene-targeting rates in vivo, with the preferential gene-editing in liver and heart, and more modest editing efficiencies in skeletal muscle, brain and gonads, directly reflecting the infection profile of the virus serotype. To track CRISPR biodistribution, I established two reporter systems that apply in situ fluorescence activation to demarcate CRISPR-targeting events at single-cell resolution, identifying rare gene-edited cells that normally evade detection by sequencing. This exquisite detection sensitivity further allows evaluation of inter-generational transmission of gene-editing viruses. Finally, although Cas9 elicits host immune responses, these can be ameliorated by immunosuppression. I also identified a public Cas9-responsive T-cell clonotype and mapped the B-cell epitopes on Cas9 and AAV. Engineering tolerance to immunodominant epitopes may provide an avenue for avoiding immune rejection of AAV-CRISPR. The ability to create programmable genetic modifications in multiple organs of postnatal mammals provides a powerful tool for biological research, and foretells that the genomes of whole mammals may be rewritten at will.Medical Science

Anonymity, pen-name identified, and identified groups in group decision support systems : performance and perception measures

This research focused on the effect of using total anonymity and pen-names (a form of anonymity) in computer conferences for group decision making. The subjects are NTU Accountancy undergraduates. Totally identified control groups meetings were also conducted so that the 3 different groups can be compared based on a set of performance and perception measures.ACCOUNTANC

The underpricing of IPOs in Singapore

Our report provides a study of the degree of underpricing on a sample of initial public offerings (IPOs) listed on the Stock Exchange of Singapore (SES) and the impact of certain issue-related characteristics on the degree of underpricing. Examples include IPO size, number of shares issued, and oversubscription ratio. The conclusions reached are derived from the results of tests conducted on a set of published data from various SES publications. To provide a more comprehensive report on the issue of underpriced IPOs in Singapore, research is done on the process of issuing new shares, reasons for the underpricing of IPOs, problems of this phenomenon and possible solutions to remedy the problems.ACCOUNTANC

Miniature single-mode fiber refractive index interferometer sensor based on high order cladding mode and core-offset

A miniature single-mode fiber (SMF) refractive index (RI) interferometer sensor based on high order cladding mode and core offset is presented. The sensor is fabricated by first splicing a very short SMF to another SMF with core-offset to induce cladding mode propagation along the short SMF. The end of the SMF will be melted into a rounded tip to excite the propagating cladding mode into higher order at reflection which creates large phase delay. High RI sensitivity of 1.24 × 10-4 refractive index unit (RIU) and 8.35 × 10-5 RIU for RIU of 1.3350 and 1.3845, are obtained, respectively, for the physical length of 690- μm sensor