Human Post-Translational SUMOylation Modification of SARS-CoV-2 Nucleocapsid Protein Enhances Its Interaction Affinity with Itself and Plays a Critical Role in Its Nuclear Translocation.

Viruses, such as Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), infect hosts and take advantage of host cellular machinery for genome replication and new virion production. Identifying and elucidating host pathways for viral infection is critical for understanding the development of the viral life cycle and novel therapeutics. The SARS-CoV-2 N protein is critical for viral RNA (vRNA) genome packaging in new virion formation.

Human SUMOylation Pathway Is Critical for Influenza B Virus.

The identification and elucidation of host pathways for viral infection are critical for understanding the viral infection processes and novel therapeutics development. Here, for the first time, we discover that the human SUMOylation pathway is essential for the IBV viral life cycle. First, IBV viruses were completely inhibited by a novel SUMOylation specific inhibitor, STE025, discovered from our FRET-based high-throughput screening, and the inhibition was very potent, with IC~ 0.

Encapsulating Polyethyleneimine-DNA Nanoplexes into PEGylated Biodegradable Microparticles Increases Transgene Expression In Vitro and Reduces Inflammatory Responses In Vivo.

Encapsulating genetic material into biocompatible polymeric microparticles is a means to improving gene transfection while simultaneously decreasing the tendency for inflammatory responses; and can be advantageous in terms of delivering material directly to the lungs via aerosolization for applications such as vaccinations. In this study, we investigated the advantages of using polymeric microparticles carrying the luciferase reporter gene in increasing transfection efficiency in the readily transfectable HEK293 cell line and the difficult to transfect RAW264.7 cell line.

Implantable Osmotic Transport Device Can Reduce Edema After Severe Contusion Spinal Cord Injury.

Recent findings from the ISCoPe study indicate that, after severe contusion to the spinal cord, edema originating in the spinal cord accumulates and compresses the tissue against the surrounding dura mater, despite decompressive laminectomy. It is hypothesized that this compression results in restricted flow of cerebrospinal fluid (CSF) in the subarachnoid space and central canal and ultimately collapses local vasculature, exacerbating ischemia and secondary injury. Here we developed a surgically mounted osmotic transport device (OTD) that rests on the dura and can osmotically remove excess fluid at the injury site.

The latency of peroxisomal catalase in terms of effectiveness factor for pancreatic and glioblastoma cancer cell lines in the presence of high concentrations of HO: Implications for the use of pharmacological ascorbate in cancer therapy.

Previous research has identified variation in cancer cell line response to high levels of extracellular HO (eHO) exposure. This directly contributes to our understanding cellular efficacy of pharmacological ascorbate (P-AscH) therapy. Here we investigate the factors contributing to latency of peroxisomal catalase of a cell and the importance of latency in evaluating cell exposure to eHO.

Single and binary protein electroultrafiltration using poly(vinyl-alcohol)-carbon nanotube (PVA-CNT) composite membranes.

Electrically conductive composite ultrafiltration membranes composed of carbon nanotubes have exhibited efficient fouling inhibition in wastewater treatment applications. In the current study, poly(vinyl-alcohol)-carbon nanotube membranes were applied to fed batch crossflow electroultrafiltration of dilute (0.1 g/L of each species) single and binary protein solutions of α-lactalbumin and hen egg-white lysozyme at pH 7.

Finding the optimal design of a passive microfluidic mixer.

The ability to thoroughly mix two fluids is a fundamental need in microfluidics. While a variety of different microfluidic mixers have been designed by researchers, it remains unknown which (if any) of these mixers are optimal (that is, which designs provide the most thorough mixing with the smallest possible fluidic resistance across the mixer). In this work, we automatically designed and rationally optimized a microfluidic mixer.

Development and applications of a concentrating membrane osmometer for colloid solutions.

The membrane concentration osmometer coupled with multiple sample preparations has been used for over a century to determine a number of colloidal properties. At the dilute region, this method has been used to determine solute molecular mass. When the solution is proteinaceous, in the intermediate region, the osmotic pressure profile provides the second virial coefficient, useful for estimating protein crystallization and salting out.

Tunable Properties of Poly-DL-Lactide-Monomethoxypolyethylene Glycol Porous Microparticles for Sustained Release of Polyethylenimine-DNA Polyplexes.

Direct pulmonary delivery is a promising step in developing effective gene therapies for respiratory disease. Gene therapies can be used to treat the root cause of diseases, rather than just the symptoms. However, developing effective therapies that do not cause toxicity and that successfully reach the target site at therapeutic levels is challenging.

Interrogating the Osmotic Pressure of Self-Crowded Bovine Serum Albumin Solutions: Implications of Specific Monovalent Anion Effects Relative to the Hofmeister Series.

The free-solvent-based (FSB) model and osmotic pressure were used to probe the ion binding and protein hydration for self-crowded bovine serum albumin in 0.15 M NaF, NaCl, NaI, and NaSCN solutions. All experiments were conducted with solutions at pH 7.

Calculated cell-specific intracellular hydrogen peroxide concentration: Relevance in cancer cell susceptibility during ascorbate therapy.

The high extracellular hydrogen peroxide (HO) concentrations generated during pharmacological ascorbate (P-AscH) therapy has been shown to exhibit a high flux into susceptible cancer cells leading to a decrease in clonogenic survival. It is hypothesized that the intracellular HO concentration for susceptibility is independent of cell type and that the variation observed in dosing is associated with differences in the cell-specific overall steady-state intracellular HO concentration values. The steady-state variation in intracellular HO concentration is coupled to a number of cellular specific transport and reaction factors including catalase activity and membrane permeability.

Instantaneous simulation of fluids and particles in complex microfluidic devices.

Microfluidics researchers are increasingly using computer simulation in many different aspects of their research. However, these simulations are often computationally intensive: simulating the behavior of a simple microfluidic chip can take hours to complete on typical computing hardware, and even powerful workstations can lack the computational capabilities needed to simulate more complex chips. This slows the development of new microfluidic chips for new applications.

MOPSA: A microfluidics-optimized particle simulation algorithm.

Computer simulation plays a growing role in the design of microfluidic chips. However, the particle tracers in some existing commercial computational fluid dynamics software are not well suited for accurately simulating the trajectories of particles such as cells, microbeads, and droplets in microfluidic systems. To address this issue, we present a microfluidics-optimized particle simulation algorithm (MOPSA) that simulates the trajectories of cells, droplets, and other particles in microfluidic chips with more lifelike results than particle tracers in existing commercial software.

Peroxiporin Expression Is an Important Factor for Cancer Cell Susceptibility to Therapeutic H2O2: Implications for Pharmacological Ascorbate Therapy.

Cancer cell toxicity to therapeutic H2O2 varies widely depending on cell type. Interestingly, it has been observed that different cancer cell types have varying peroxiporin expression. We hypothesize that variation in peroxiporin expression can alter cell susceptibility to therapeutic H2O2 concentrations.

MECs: "Building Blocks" for Creating Biological and Chemical Instruments.

The development of new biological and chemical instruments for research and diagnostic applications is often slowed by the cost, specialization, and custom nature of these instruments. New instruments are built from components that are drawn from a host of different disciplines and not designed to integrate together, and once built, an instrument typically performs a limited number of tasks and cannot be easily adapted for new applications. Consequently, the process of inventing new instruments is very inefficient, especially for researchers or clinicians in resource-limited settings.

Reduction of Cerebral Edema via an Osmotic Transport Device Improves Functional Outcome after Traumatic Brain Injury in Mice.

Traumatic brain injury (TBI), the foremost cause of morbidity and mortality in persons under 45 years of age worldwide, leads to about 200,000 victims requiring hospitalization and approximately 52,000 deaths per year in the United States. TBI is characterized by cerebral edema leading to raised intracranial pressure, brain herniation, and subsequent death. Current therapies for TBI treatment are often ineffective, thus novel therapies are needed.

Comparative endothelial cell response on topographically patterned titanium and silicon substrates with micrometer to sub-micrometer feature sizes.

In this work, we evaluate the in vitro response of endothelial cells (EC) to variation in precisely-defined, micrometer to sub-micrometer scale topography on two different substrate materials, titanium (Ti) and silicon (Si). Both substrates possess identically-patterned surfaces composed of microfabricated, groove-based gratings with groove widths ranging from 0.5 to 50 µm, grating pitch twice the groove width, and groove depth of 1.

Reduction of cerebral edema after traumatic brain injury using an osmotic transport device.

Traumatic brain injury (TBI) is significant, from a public health standpoint, because it is a major cause of the morbidity and mortality of young people. Cerebral edema after a TBI, if untreated, can lead to devastating damage of the remaining tissue. The current therapies of severe TBI (sTBI), as outlined by the Brain Trauma Foundation, are often ineffective, thus a new method for the treatment of sTBI is necessary.

A generalized free-solvent model for the osmotic pressure of multi-component solutions containing protein-protein interactions.

The free-solvent model has been shown to have excellent predictability of the osmotic pressure for single and binary non-interactive proteins in aqueous solutions. Here the free-solvent model is extended to be more generalized by including the contributions of intra- and inter-protein interactions to the osmotic pressure of a solution in the form of homo- and hetero-multimers. The solute-solvent interactions are considered to be unique for each homo- and hetero-multimer in solution.

Predicting the activity coefficients of free-solvent for concentrated globular protein solutions using independently determined physical parameters.

The activity coefficient is largely considered an empirical parameter that was traditionally introduced to correct the non-ideality observed in thermodynamic systems such as osmotic pressure. Here, the activity coefficient of free-solvent is related to physically realistic parameters and a mathematical expression is developed to directly predict the activity coefficients of free-solvent, for aqueous protein solutions up to near-saturation concentrations. The model is based on the free-solvent model, which has previously been shown to provide excellent prediction of the osmotic pressure of concentrated and crowded globular proteins in aqueous solutions up to near-saturation concentrations.

Interpretation of negative second virial coefficients from non-attractive protein solution osmotic pressure data: an alternate perspective.

A negative second virial coefficient has long been a predictor of potential protein crystallization and salting out. However, the assumption that this is due to attractive solute-solute interactions remains a source of debate. Here we reexamine the second virial coefficient from protein osmometry in terms of the free-solvent model.

Electrostatic properties of confluent Caco-2 cell layer correlates to their microvilli growth and determines underlying transcellular flow.

Recently, Rajapaksa et al. (2010) showed that the rate of uptake of potential vaccine delivery nanoparticles in the mucosal layer is a function of the electrostatic properties of the corresponding solvent. This fundamentally implies that the dominant driving forces that may be capitalized on for mucosal vaccine strategies are electrostatic in nature.

Novel in situ normal streaming potential device for characterizing electrostatic properties of confluent cells.

The characteristics of transport across confluent cell monolayers may often be attributed to its electrostatic properties. While tangential streaming potential is often used to quantify these electrostatic properties, this method is not effective for transport normal to the apical cell surface where the charge properties along the basolateral sides may be important (i.e.

Engineering excellence in breakthrough biomedical technologies: bioengineering at the University of California, Riverside.

The Department of Bioengineering at the University of California, Riverside (UCR), was established in 2006 and is the youngest department in the Bourns College of Engineering. It is an interdisciplinary research engine that builds strength from highly recognized experts in biochemistry, biophysics, biology, and engineering, focusing on common critical themes. The range of faculty research interests is notable for its diversity, from the basic cell biology through cell function to the physiology of the whole organism, each directed at breakthroughs in biomedical devices for measurement and therapy.

Protein interaction affinity determination by quantitative FRET technology.

The dissociation constant, K(d) , is an important parameter for characterizing protein-protein interaction affinities. SUMOylation is one of the important protein post-translational modifications and it involves a multi-step enzymatic cascade reaction, resulting in peptide activation and substrate conjugation. Multiple covalent and non-covalent protein-protein interactions are involved in this cascade.