Interaction profiling methods to map protein and pathway targets of bioactive ligands.

Recent advances in -omic profiling technologies have ushered in an era where we no longer want to merely measure the presence or absence of a biomolecule of interest, but instead hope to understand its function and interactions within larger signaling networks. Here, we review several emerging proteomic technologies capable of detecting protein interaction networks in live cells and their integration to draft holistic maps of proteins that respond to diverse stimuli, including bioactive small molecules. Moreover, we provide a conceptual framework to combine so-called 'top-down' and 'bottom-up' interaction profiling methods and ensuing proteomic profiles to directly identify binding targets of small molecule ligands, as well as for unbiased discovery of proteins and pathways that may be directly bound or influenced by those first responders. The integrated, interaction-based profiling methods discussed here have the potential to provide a unique and dynamic view into cellular signaling networks for both basic and translational biological studies.

High throughput discovery of functional protein modifications by Hotspot Thermal Profiling.

Mass spectrometry enables global analysis of posttranslationally modified proteoforms from biological samples, yet we still lack methods to systematically predict, or even prioritize, which modification sites may perturb protein function. Here we describe a proteomic method, Hotspot Thermal Profiling, to detect the effects of site-specific protein phosphorylation on the thermal stability of thousands of native proteins in live cells. This massively parallel biophysical assay unveiled shifts in overall protein stability in response to site-specific phosphorylation sites, as well as trends related to protein function and structure. This method can detect intrinsic changes to protein structure as well as extrinsic changes to protein-protein and protein-metabolite interactions resulting from phosphorylation. Finally, we show that functional 'hotspot' protein modification sites can be discovered and prioritized for study in a high-throughput and unbiased fashion. This approach is applicable to diverse organisms, cell types and posttranslational modifications.

A randomized controlled trial of oral chloral hydrate vs intranasal dexmedetomidine plus buccal midazolam for auditory brainstem response testing in children.

BACKGROUND: Moderate to deep sedation is required for an auditory brainstem response test when high-intensity stimulation is used. Chloral hydrate is the most commonly used sedative, whereas intranasal dexmedetomidine is increasingly used in pediatric non-painful procedural sedations. OBJECTIVE: The aim of this study was to compare the sedation success rate after oral chloral hydrate at 50 mg kg-1 and intranasal dexmedetomidine at 3 µg kg-1 plus buccal midazolam at 0.1 mg kg-1 for an auditory brainstem response test. METHODS: Children who required an auditory brainstem response test were recruited and randomly assigned to receive oral chloral hydrate at 50 mg kg-1 and intranasal placebo, or intranasal dexmedetomidine at 3 µg kg-1 with buccal midazolam 0.1 mg kg-1 . The primary outcome was the rate of successful sedation for auditory brainstem response tests. RESULTS: Fifty-seven out of 82 (69.5%) were successfully sedated after chloral hydrate, while 70 out of 78 (89.7%) children were successfully sedated with dexmedetomidine plus midazolam combination, with the odd ratio (95% CI) for successful sedation between dexmedetomidine plus midazolam combination and chloral hydrate estimated to be 3.84 (1.61-9.16), P = 0.002. Dexmedetomidine plus midazolam was associated with quicker onset with median onset time 15 (IQR 11.0-19.8) for dexmedetomidine plus midazolam and 20 (IQR 15.0-27.0) for chloral hydrate respectively, with difference between median (95% CI) of 5 [3-8], P < 0.0001). The behavior observed during drug administration of intranasal dexmedetomidine and buccal midazolam was better that of the children who had oral chloral hydrate. No children required oxygen therapy or medical intervention for hemodynamic disturbances in this study and the incidence of hypotension and bradycardia was similar. CONCLUSION: Intranasal dexmedetomidine plus buccal midazolam was associated with higher sedation success with deeper level of sedation, with similar discharge time and adverse event rate when compared to chloral hydrate.

Intranasal dexmedetomidine for sedation in children undergoing transthoracic echocardiography study--a prospective observational study.

BACKGROUND: Intranasal dexmedetomidine has been used for sedation in children undergoing nonpainful procedures. OBJECTIVE: The aim of this study was to determine the success rate of intranasal dexmedetomidine sedation for children undergoing transthoracic echocardiography examination. METHODS: This was a prospective observational study of 115 children under the age of 3 years undergoing echocardiography examination under sedation with intranasal dexmedetomidine at 3 mcg·kg(-1). RESULTS: Of the 115 children, 100 (87%) had satisfactory sedation with intranasal dexmedetomidine. The mean onset time was 16.7 ± 7 min (range 5-50 min). The mean wake up time was 44.3 ± 15.1 min (range 12-123 min). The wake up time was significantly correlated with duration of procedure with R = 0.540 (P < 0.001). Aside from one patient who required oxygen supplementation, all children in this investigation had an acceptable heart rate and blood pressure and required no medical intervention. CONCLUSION: Sedation by intranasal dexmedetomidine at 3 mcg·kg(-1) is associated with acceptable success rate in children undergoing echocardiography with no adverse events in this cohort.