Biology subjects

Ulery, B. D.

Publications and source records attributed to Ulery, B. D..

8 recordsLinked to original sources

bioRxiv2024

Generalization of the Packing Parameter for Quantifying the Morphology of Peptide Amphiphile Micelles

We present a quantitative means for classifying the shape of molecular dynamics simulated peptide amphiphile micelles (PAMs) that is both consistent with existing metrics and extendable to estimating shape-dependent free energy contributions. The presented framework not only outlines an approach for characterizing the shape of simulated PAMs but also presents expressions that can readily be applied to quantify the shape of particles from experimental techniques where aspect ratios are measured. The generalization of the packing parameter introduces a characteristic length that, when applied to simulated PAMs, functions intuitively as an effective radius for a PAM whose core is a perfect sphere or an infinite cylinder. The presented shape assignment scheme is used to develop a model for the free energy penalty associated with packing the tails of the amphiphiles into a core whose shape is modeled by an ellipsoid. Good agreement with previous models and scaling behaviors is observed and the importance of accounting for the shape and size dependence of the core is illustrated. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/598326v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1b326d4org.highwire.dtl.DTLVardef@ba5e82org.highwire.dtl.DTLVardef@192e29forg.highwire.dtl.DTLVardef@5c63b1_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2024

Adjuvant Delivery Method and Nanoparticle Charge Influence Peptide Amphiphile Micelle Vaccine Bioactivity

Vaccines are an indispensable public health measure that have enabled the eradication, near elimination, and prevention of a variety of pathogens. As research continues and our understanding of immunization strategies develops, subunit vaccines have emerged as exciting alternatives to existing whole vaccine approaches. Unfortunately, subunit vaccines often possess weak antigenicity, requiring delivery devices and adjuvant supplementation to improve their utility. Peptide amphiphile micelles have recently been shown to function as both delivery devices and self-adjuvanting systems that can be readily associated with molecular adjuvants to further improve vaccine-mediated host immunity. While promising, many "design rules" associated with the plethora of underlying adjustable parameters in the generation of a peptide amphiphile micelle vaccine have yet to be uncovered. This work explores the impact micellar adjuvant complexation method and incorporated antigen type have on their ability to activate dendritic cells and induce antigen specific responses. Interestingly, electrostatic complexation of CpG to micelles resulted in improved in vitro dendritic cell activation over hydrophobic association and antigen|adjuvant co-localization influenced cell-mediated, but not antibody-mediated immune responses. These exciting results complement those previously published to build the framework of a micelle vaccine toolbox that can be leveraged for future disease-specific formulations.

bioengineering↗

bioRxiv2024

Vasoactive Intestinal Peptide Amphiphile Micelle Material Properties Influence Their Cell Association and Internalization

Vasoactive intestinal peptide (VIP) is a promising anti-inflammatory peptide therapeutic that is known to induce biological effects by interacting with its cognate receptor (i.e., VPAC) on the surface of antigen presenting cells (APCs). For VIP-based drug delivery technologies like nano- and microparticles, little is known about the effect VPAC targeting has on APC behavior. This is further influenced by the fact that particulate material properties including chemistry, shape, and size are all known to influence APC behavior. In this study, peptide amphiphile micelles (PAMs) were employed as a modifiable platform to study the impact VPAC targeting and physical particle properties have on their association with macrophages. VIP amphiphile micelles (VIPAMs) and their scrambled peptide amphiphile micelle analogs (SVIPAMs) were fabricated from various chemistries yielding particle batches that were comprised of spheres (10 - 20 nm in diameter) and/or cylinders of varying lengths (i.e., 20 - 9000 nm). Micelle surface attachment to and internalization by macrophages were observed using confocal microscopy and their association was characterized by flow cytometry. The enclosed work provides strong evidence that macrophages rapidly bind VPAC specific micelles independent of physical properties though micelle shape and size as well as receptor-specificity all influence their long-term macrophage association. Specifically, a mixture of spherical and short cylindrical VIPAMs were able to achieve the greatest cell association which may correlate to their capacity to fully bind the VPAC receptors available on the surface of macrophages. These results provide the foundation of how nano- and microparticle physical properties and targeting capacity synergistically influence their capacity to associate with APCs.

bioengineering↗

bioRxiv2024

M2e-Derived Peptidyl and Peptide Amphiphile Micelles as Novel Influenza Vaccines

A significant problem with current influenza vaccines is their reliance on predictions of what will be the most prevalent strains for the upcoming season. Mismatches between predictions and reality in any given year can greatly reduce the overall efficacy of an immunization campaign. A universal influenza vaccine, which leverages epitopes conserved across many, if not all, strains of influenza, can reduce the need for such accurate forecasting. The ectodomain of the M2 ion channel protein is highly conserved and includes a B cell epitope in the M22-16 region, making it a potentially viable candidate as a universal influenza vaccine. Unfortunately, the use of free peptide antigens as vaccines comes with several disadvantages including poor stability and weak immunogenicity in vivo. However, integrating peptide antigens into nanoparticles can avoid some of those drawbacks. Previous studies have shown that micellar nanoparticles can be generated from peptides by conjugating them with a lipid or lipids. Specifically, hydrophobically-driven, self-assembled peptide amphiphile micelles comprised of Palm2K-peptide-(KE)4 have been found to be immunostimulatory. Unlike other peptides previously used for this purpose, the M22-16 peptide interestingly formed micelles without any peptidyl or lipid modifications. Because this unmodified peptide self-assembled on its own, it enabled the decoupling of the effect of micellization on immunogenicity from the incorporation of non-vaccine components such as the addition of a lipid moiety (Palm2K) and a zwitterion-like peptide block ((KE)4). The enclosed work shows that M22-16 peptidyl micelles had some characteristic differences in shape, critical micelle concentration, and secondary structure when compared to M22-16 peptide amphiphile micelles, which produced a few differences in murine antibody responses. These results suggest that peptide amphiphile micelles could be leveraged as a one-dose vaccine, while either micelle formulation induced strong immunological responses with a prime-booster immunization regimen.

bioengineering↗

bioRxiv2024

Cytoprotective and Neuroinductive Effects of Thiol-Containing Simple Signaling Molecules

Around 20 million Americans, mostly young adults, have suffered from a peripheral nerve injury due to trauma or a medical condition. However, prevailing treatments, including those that employ exogenous growth factors, often exhibit drawbacks outweighing their benefits, highlighting the need for novel solutions. Non-complex agents that govern bioactivity, termed simple signaling molecules (SSMs), offer an exciting alternative when compared to traditional approaches due to their small size, ready availability, and influence on cellular pathways. This study explores the cytoprotective and neuroinductive effects of three thiol-containing SSMs: hydrogen sulfide (H2S), n-acetyl cysteine (NAC), and glutathione (GSH). Neural stem cells (NE-4Cs) were exposed to toxic levels of hydrogen peroxide (H2O2) while supplemented with different concentrations of H2S, NAC, or GSH to assess their cytoprotective effects. To study the neuroinductivity of H2S, NAC, and GSH with NE-4Cs, immunofluorescence microscopy for an early neuronal marker, {beta}3-tubulin, was employed to determine stem cell neural differentiation. Significant cytoprotection was found for NAC (2 - 8 mM) and GSH (2 - 12 mM), while H2S showed limited protective effects. Interestingly, the opposite result was observed for neuroinductivity as only H2S (7.75 - 125 M) achieved a desirable effect while NAC and GSH had minimal impact on neural differentiation. This research establishes therapeutic concentration ranges of H2S, NAC, and GSH for future drug delivery systems targeting neural regeneration, especially for peripheral nerve injuries. LAY SUMMARYApproximately 20 million Americans, mainly young adults, suffer from peripheral nerve injuries, necessitating new effective treatments. Currently emerging approaches, including growth factor-based therapies, unfortunately face considerable limitations. This study explores the potential of simple signaling molecules (SSMs) - small, readily available agents - specifically hydrogen sulfide (H2S), n-acetyl cysteine (NAC), and glutathione (GSH) for their potential to be used to address issues underlying peripheral nerve injuries. Our findings reveal NAC and GSH have cytoprotective effects, whereas H2S is neuroinductive. This research identifies optimal concentrations for future drug delivery targeting neural regeneration, especially beneficial for peripheral nerve injuries. FUTURE WORKSUpcoming investigation will concentrate on exploiting the potential of novel SSM-releasing monomers within degradable polymeric systems. This involves defining therapeutic windows and optimizing polymer chemistry to induce desired cytoprotective and neuroinductive effects in neural stem cells, crucial for peripheral nerve injury repair. Emphasizing controlled release, this approach holds promise for developing advanced therapeutic strategies utilizing H2S, NAC, and/or GSH in nerve guidance conduits. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/597935v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@187657dorg.highwire.dtl.DTLVardef@17ffa9org.highwire.dtl.DTLVardef@191dc67org.highwire.dtl.DTLVardef@11d0fd2_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2022

Spinal Fusion Properties of Mechanically-Reinforced, Osteomodulatory Chitosan Hydrogels

Lower back pain is a considerable medical problem that will impact 80% of the U.S. population at some point in their life. For the most severe cases, surgical repair is necessary and is associated with costs upwards of $10.2 billion annually in the United States. To alleviate back pain, spine fusions are a common treatment in which two or more vertebrae are biologically fused together often through the use of a graft material. Unfortunately, iliac crest bone autograft, the current gold standard graft material, can yield insufficient fusion and is associated with considerable donor site morbidity and pain as well as limited supply. Therefore, new materials need to be developed in order to better coordinate healing and new bone growth in the affected area to reduce unnecessary patient burden. In order to address this issue, the incorporation of allograft and one of two types of cellulose (i.e., 0CNCs and CNFs) into a dual-crosslinked chitosan hydrogel loaded with bioactive calcium phosphate was investigated. Hydrogels were then tested for both their material and biological properties. Specifically, hydrogel swelling ratio, mass loss, ion release profile, compressive strength, in vitro biocompatibility and osteoinduction as well as in vivo biocompatibility, and effectiveness in a spine fusion model were determined. Cellulose and allograft incorporation significantly improved hydrogel compressive strength and biocompatibility and CNFs were found to be a significantly more biocompatible form of cellulose than 0CNCs. Additionally, through the controlled delivery of osteoinductive simple signaling molecules (i.e., calcium and phosphate ions), DCF-loaded CNF/Chitosan hydrogels were able to induce osteoblast-like activity in murine mesenchymal stem cells. When evaluated in vivo, these hydrogels were found to be non-toxic though the subacute phase (14 days). A 6-week rabbit spine fusion found these materials to achieve near complete fusion when assessed radiographically. This research provides considerable support for the utility of our novel material for spine fusion procedures as well as other future bone applications.

bioengineering↗

bioRxiv2021

Vasoactive Intestinal Peptide Amphiphile Micelle Chemical Structure and Hydrophobic Domain Influence Immunomodulatory Potentiation

Vasoactive intestinal peptide (VIP) is a neuropeptide capable of downregulating innate immune responses in antigen presenting cells (APCs) by suppressing their pro-inflammatory cytokine secretion and cell surface marker expression. Though VIPs bioactivity could possibly be leveraged as a treatment for autoimmune disorders and transplant tolerance, drug delivery innovation is required to overcome its intrinsically limited cellular delivery capacity due to its short in vivo lifetime. One option is to employ peptide amphiphiles (PAs) which are lipidated peptides capable of self-assembling into micelles in water that can enhance cellular association. With this approach in mind, a series of triblock VIP amphiphiles (VIPAs) has been synthesized to explore the influence of block arrangement and hydrophobicity on micelle biocompatibility and bioactivity. VIPA formulation has been found to influence the shape, size, and surface charge of VIPA micelles (VIPAMs) as well as their cytotoxicity and immunomodulatory effects. Specifically, the enclosed work provides strong evidence that cylindrical VIPAMs with aspect ratios of 1.5 - 150 and moderate positive surface charge are able to potentiate the bioactivity of VIP limiting TNF- secretion and MHC II and CD86 surface expression on APCs. With this criteria, we have identified PalmK-(EK)4-VIP as our lead formulation, which showed comparable or enhanced anti-inflammatory effects relative to the unmodified VIP at all dosages evaluated. Additionally, the relationships between peptide block location and lipid block size provide further information on the chemistry-structure-function relationships of peptide amphiphile micelles for the delivery of VIP as well as potentially for other peptides more broadly.

bioengineering↗

bioRxiv2020

Lipidated poly(amino acid) nanostructures as versatile therapeutic delivery vehicles

Poly(amino acid)s are a diverse and capable class of polymers with significant potential for utilization in a wide variety of drug delivery applications. A sub-class of these biomaterials known as lipidated poly(amino acid)s (LPAAs) are amphiphiles composed of both hydrophobic and hydrophilic domains yielding interesting physical properties. In this article, we describe our efforts in developing a novel class of lysine and valine containing LPAAs synthesized via hexadecylamine initiated N-carboxyanhydride ring-opening polymerization (NCA-ROP). These highly hydrophobic LPAAs were found capable of undergoing hydrophobically-driven self-assembly into small nanostructures as well as being forced into larger nanostructures using a novel dump-and-stir nanoprecipitation process. This process yielded fine control over resulting nanoparticle size and cargo entrapment. Furthermore, cell-targeting DNA aptamer modification of doxorubicin-loaded LPAA nanoparticles induced significant death of co-incubated Non-Hodgkin Lymphoma cells providing exciting evidence of the therapeutic potential of this novel biomaterials-based delivery device.

bioengineering↗