Characterization of the G-quadruplexes in the duplex nuclease hypersensitive element of the PDGF-A promoter and modulation of PDGF-A promoter activity by TMPyP4

The proximal 5′-flanking region of the human platelet-derived growth factor A (PDGF-A) promoter contains one nuclease hypersensitive element (NHE) that is critical for PDGF-A gene transcription. On the basis of circular dichroism (CD) and electrophoretic mobility shift assay (EMSA), we have shown that the guanine-rich (G-rich) strand of the DNA in this region can form stable intramolecular parallel G-quadruplexes under physiological conditions. A Taq polymerase stop assay has shown that the G-rich strand of the NHE can form two major G-quadruplex structures, which are in dynamic equilibrium and differentially stabilized by three G-quadruplex-interactive drugs. One major parallel G-quadruplex structure of the G-rich strand DNA of NHE was identified by CD and dimethyl sulfate (DMS) footprinting. Surprisingly, CD spectroscopy shows a stable parallel G-quadruplex structure formed within the duplex DNA of the NHE at temperatures up to 100°C. This structure has been characterized by DMS footprinting in the double-stranded DNA of the NHE. In transfection experiments, 10 μM TMPyP4 reduced the activity of the basal promoter of PDGF-A ∼40%, relative to the control. On the basis of these results, we have established that ligand-mediated stabilization of G-quadruplex structures within the PDGF-A NHE can silence PDGF-A expression

Inhibition of the Ubc9 E2 SUMO-conjugating enzyme-CRMP2 interaction decreases NaV1.7 currents and reverses experimental neuropathic pain

We previously reported that destruction of the small ubiquitin-like modifier (SUMO) modification site in the axonal collapsin response mediator protein 2 (CRMP2) was sufficient to selectively decrease trafficking of the voltage-gated sodium channel NaV1.7 and reverse neuropathic pain. Here, we further interrogate the biophysical nature of the interaction between CRMP2 and the SUMOylation machinery, and test the hypothesis that a rationally designed CRMP2 SUMOylation motif (CSM) peptide can interrupt E2 SUMO-conjugating enzyme Ubc9-dependent modification of CRMP2 leading to a similar suppression of NaV1.7 currents. Microscale thermophoresis and amplified luminescent proximity homogeneous alpha assay revealed a low micromolar binding affinity between CRMP2 and Ubc9. A heptamer peptide harboring CRMP2's SUMO motif, also bound with similar affinity to Ubc9, disrupted the CRMP2-Ubc9 interaction in a concentration-dependent manner. Importantly, incubation of a tat-conjugated cell-penetrating peptide (t-CSM) decreased sodium currents, predominantly NaV1.7, in a model neuronal cell line. Dialysis of t-CSM peptide reduced CRMP2 SUMOylation and blocked surface trafficking of NaV1.7 in rat sensory neurons. Fluorescence dye-based imaging in rat sensory neurons demonstrated inhibition of sodium influx in the presence of t-CSM peptide; by contrast, calcium influx was unaffected. Finally, t-CSM effectively reversed persistent mechanical and thermal hypersensitivity induced by a spinal nerve injury, a model of neuropathic pain. Structural modeling has now identified a pocket-harboring CRMP2's SUMOylation motif that, when targeted through computational screening of ligands/molecules, is expected to identify small molecules that will biochemically and functionally target CRMP2's SUMOylation to reduce NaV1.7 currents and reverse neuropathic pain

Therapeutic Molecular Targeting of Polo-Like Kinase 4 for Cancer Treatment

Class of 2015 AbstractObjectives: Two characterized peptide substrates were assayed with human Polo-like kinase 4 to determine phosphorylation activity. A pilot library of Type-II kinase inhibitors designed to fit into the ATP-binding pocket will be screened to determine HsPlk4 inhibition activity, which will help characterize a novel drug compound. Methods: Two peptide substrates of varying concentrations (2 uM, 1 uM, and 0.5 uM) were each combined with serial dilutions of HsPlk4 (1.25 uM, 0.625 uM, 0.313 uM, 0.156 uM, 0.078 uM, and 0.039 uM). EZ Reader detected phosphorylation activity by measuring fluorescence of both substrate and product, which separated at respective time points based on electrophoresis. The subsequent part of the experiment will be to inhibit the kinase activity with molecular inhibitors. Results: The results showed HsPlk4 activity with the modified PLKtide, (5FAM)KKKTPSDSLYDDGLSKK(CONH2). All reactions with the various concentrations of substrate 1 and HsPlk4 showed phosphorylation activity. The reaction started within the first 10 minutes, quickly reaching maximal phosphorylation of substrate. No p-values were calculated due to lack of data. Conclusions: No overall conclusions can be drawn based on the current results. Results showed the reaction reached its saturation point, so methods need to be refined to obtain data within the first 10 minutes. HsPlk4 phosphorylation of PLKtide confirmed the presumption that PLK family is a conserved family of Ser/Thr kinases. There are practical limitations for obtaining good kinetics data depicting enzyme activity, such as having EZ Reader quickly sample the reaction.This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Librarian and Clinical Instructor, Pharmacy Practice and Science, [email protected]

TIXT : an extensible testbed for tactile internet communication

The field of teleoperation coupled with force-feedback will undergo a paradigm shift in the forthcoming years with the advent of Tactile Internet (TI). Through TI, humankind will enjoy the ability to control and manipulate remote environments in real time by creating a perception of physical collocation for the human operator. While research and development in TI have seen a surge in the past few years, the overall progress is constrained by two major barriers. First, lack of a TI testbed has made it difficult to establish a performance benchmark. Second, asynchronous efforts led by sub-groups belonging to different research disciplines have severely impeded the overall progress of TI. In this work, we take the first step toward addressing these open issues by developing a common testbed for TI applications -- Tactile Internet eXtensible Testbed (TIXT). We begin by presenting a classification of the diverse range of TI applications. This helps in making TIXT generic, modular, and extensible. We then present the design principles of TIXT and shed light on its implementation guidelines. Finally, we present the proof of concept of TIXT through demonstration of two realistic use cases of TI

Melasma update

Melasma is an acquired pigmentary disorder characterized by symmetrical hyperpigmented macules on the face. Its pathogenesis is complex and involves the interplay of various factors such as genetic predisposition, ultraviolet radiation, hormonal factors, and drugs. An insight into the pathogenesis is important to devise treatment modalities that accurately target the disease process and prevent relapses. Hydroquinone remains the gold standard of treatment though many newer drugs, especially plant extracts, have been developed in the last few years. In this article, we review the pathogenetic factors involved in melasma. We also describe the newer treatment options available and their efficacy. We carried out a PubMed search using the following terms "melasma, pathogenesis, etiology, diagnosis, treatment" and have included data of the last few years

Toward enabling high-five over WiFi : a tactile internet paradigm

The next frontier for immersive applications is enabling sentience over the Internet. Tactile Internet (TI) envisages transporting skills by providing ultra-low-latency (ULL) communications for transporting touch senses. In this work, we focus our study on the first/last mile communication, where the future generation WiFi-7 is pitched as the front-runner for ULL applications. We discuss a few candidate features of WiFi-7 and highlight its major pitfalls with respect to ULL communication. Further, through a specific implementation of WiFi-7 (vanilla WiFi-7) in our custom simulator, we demonstrate the impact of one of the pitfalls - the standard practice of using jitter buffer in conjunction with frame aggregation - on TI communication. To circumvent this, we propose the Non-Buffered Scheme (NoBuS) - a simple MAC layer enhancement for enabling TI applications over WiFi-7. NoBuS trades off packet loss for latency, enabling swift synchronization between the master and controlled domains. Our findings reveal that employing NoBuS yields a significant improvement in RMSE of TI signals. Further, we show that the worst case WiFi latency with NoBuS is 3.72 ms - an order of magnitude lower than vanilla WiFi-7 even under highly congested network conditions