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Annelise  Barron

    Annelise Barron

    Antimicrobial peptides (AMPs) are promising therapeutics in the fight against multidrug‐resistant bacteria. As a mimic of AMPs, peptoids with N‐substituted glycine backbone have been utilized for antimicrobials with resistance against... more
    Antimicrobial peptides (AMPs) are promising therapeutics in the fight against multidrug‐resistant bacteria. As a mimic of AMPs, peptoids with N‐substituted glycine backbone have been utilized for antimicrobials with resistance against proteolytic degradation. Antimicrobial peptoids are known to kill bacteria by membrane disruption; however, the nonspecific aggregation of intracellular contents is also suggested as an important bactericidal mechanism. Here,structure‐activity relationship (SAR) of a library of indole side chain‐containing peptoids resulting in peptoid 29 as a hit compound is investigated. Then, quantitative morphological analyses of live bacteria treated with AMPs and peptoid 29 in a label‐free manner using optical diffraction tomography (ODT) are performed. It is unambiguously demonstrated that both membrane disruption and intracellular biomass flocculation are primary mechanisms of bacterial killing by monitoring real‐time morphological changes of bacteria. These multitarget mechanisms and rapid action can be a merit for the discovery of a resistance‐breaking novel antibiotic drug.
    A novel, replaceable polymer matrix based on a new N-substituted acrylamide monomer Duramide™ has been synthesized for application in DNA separations by microchannel electrophoresis. The monomer was found to be more hydrophilic than both... more
    A novel, replaceable polymer matrix based on a new N-substituted acrylamide monomer Duramide™ has been synthesized for application in DNA separations by microchannel electrophoresis. The monomer was found to be more hydrophilic than both acrylamide and N, N-dimethylacrylamide (DMA). Polymers were synthesized by free radical polymerization in aqueous solution and characterized by tandem gel permeation chromatography — multi-angle laser light scattering. PolyDuramide™ exhibits good capillary-coating ability via adsorption from aqueous solution, efficiently suppressing electroosmotic flow (EOF) in a manner comparable to that of poly-N,N-dimethylacrylamide (PDMA). Under DNA sequencing conditions, adsorptive polyDuramide™ coatings proved to be stable and to maintain negligible EOF for over 600 hours of electrophoresis. Resolution of DNA sequencing fragments, particularly fragments > 500 bases, in the novel matrix generally improves with increasing polymer concentration and decreasing electric field strength. Using polyDuramide both as a separation matrix and as a dynamic coating in bare fused silica capillaries, the matrix can resolve over 620 bases of contiguous DNA sequence within about 3 hours. Within a glass chip, the same results could likely be achieved in ∼30 minutes. These results demonstrate the potential of the novel matrix for use in DNA separation, as well as proteins, by microchannel electrophoresis.
    This work is motivated by the need to develop integrated point-of-care devices that can quickly and accurately screen users for possible health risks ranging from cancer to biological agent exposure. Commercially available screening... more
    This work is motivated by the need to develop integrated point-of-care devices that can quickly and accurately screen users for possible health risks ranging from cancer to biological agent exposure. Commercially available screening techniques, such as ELISA, take several hours to complete and are not capable of achieving the sensitivities necessary for early detection of many diseases. The use of microfluidics is a possible solution to overcome these limitations, but much is still unknown about this area. We are investigating ...
    Peptidomimetics offer opportunities for molecular engineers and materials scientists to complement and even to supersede biological polymers. An overview of some interesting classes of peptidomimetics is given and important considerations... more
    Peptidomimetics offer opportunities for molecular engineers and materials scientists to complement and even to supersede biological polymers. An overview of some interesting classes of peptidomimetics is given and important considerations guiding the development of ‘peptoids’ (sequence-specific poly-N-substituted glycines) are highlighted. We discuss the synthesis, purification, and characterization of peptoid oligomers and polymers made on solid phase and in solution phase. We review applications in which peptoids provide alternatives to natural biopolymers, for example, mimicry of the anti-infective properties of natural host defense peptides. The potential of the same polypeptoids as anticancer agents is also demonstrated and discussed.
    Visceral leishmaniasis (VL) is among the most neglected tropical diseases in the world. Drug cell permeability is essential for killing the intracellular residing parasites responsible for VL, making cell‐permeating peptides a logical... more
    Visceral leishmaniasis (VL) is among the most neglected tropical diseases in the world. Drug cell permeability is essential for killing the intracellular residing parasites responsible for VL, making cell‐permeating peptides a logical choice to address VL. Unfortunately, the limited biological stability of peptides restricts their usage. Sequence‐specific oligo‐N‐substituted glycines (‘peptoids’) are a class of peptide mimics that offers an excellent alternative to peptides in terms of ease of synthesis and good biostability. We tested peptoids against the parasite Leishmania donovani in both forms, that is, intracellular amastigotes and promastigotes. N‐alkyl hydrophobic chain addition (lipidation) and bromination of oligopeptoids yielded compounds with good antileishmanial activity against both forms, showing the promise of these antiparasitic peptoids as potential drug candidates to treat VL.
    Background There is an urgent need for therapeutic approaches that can prevent or limit neuroinflammatory processes and prevent neuronal degeneration. Photobiomodulation (PBM), the therapeutic use of specific wavelengths of light, is a... more
    Background There is an urgent need for therapeutic approaches that can prevent or limit neuroinflammatory processes and prevent neuronal degeneration. Photobiomodulation (PBM), the therapeutic use of specific wavelengths of light, is a safe approach shown to have anti-inflammatory effects. The current study was aimed at evaluating the effects of PBM on LPS-induced peripheral and central inflammation in mice to assess the potential of PBM as an anti-inflammatory treatment. Methods Effects of PBM were evaluated in group-housed C57BL/6J mice. Mice were divided into three groups: (a) a control group receiving no PBM, (b) a group receiving PBM utilizing red/NIR light at 640 and 880 nm (RL), and (c) a group receiving RL with a 40 Hz gamma frequency flicker (RLG). PBM was administered over 12 days (5 days per week for 2 weeks; no treatment on days 6 and 7). Each PBM treatment was 30 minutes. On day 11, mice were dosed by intraperitoneal injection with either vehicle or LPS (1 mg/kg). Brain...
    Bacterial contamination of an exposed implantable medical device by the atmosphere of an operating room (OR) is increasingly implicated as a cause of device‐associated infection. Here, OR contamination is modeled in vitro using an... more
    Bacterial contamination of an exposed implantable medical device by the atmosphere of an operating room (OR) is increasingly implicated as a cause of device‐associated infection. Here, OR contamination is modeled in vitro using an aerosolizing system to spray small quantities of staphylococci onto titanium rods. Contaminated rods always manifest culturable bacteria. Self‐assembly is used to create a self‐defensive Ti surface that substantially enhances the rod's resistance to such contamination. Poly(acrylic acid) microgels are electrostatically deposited onto small Ti rods and subsequently loaded by complexation with a cationic antimicrobial peptoid (TM1). The microgels are visualized in situ by optical microscopy, and changes in microgel diameter indicate the loading state. These measurements show that TM1 can be quickly loaded from low‐ionic‐strength buffer and subsequently remained sequestered within the microgels for up to 4 weeks when soaked in phosphate buffered saline. T...
    The rising incidence of antibiotic-resistant lung infections has instigated a much-needed search for new therapeutic strategies. One proposed strategy is the use of exogenous surfactants to deliver antimicrobial peptides (AMPs), like... more
    The rising incidence of antibiotic-resistant lung infections has instigated a much-needed search for new therapeutic strategies. One proposed strategy is the use of exogenous surfactants to deliver antimicrobial peptides (AMPs), like CATH-2, to infected regions of the lung. CATH-2 can kill bacteria through a diverse range of antibacterial pathways and exogenous surfactant can improve pulmonary drug distribution. Unfortunately, mixing AMPs with commercially available exogenous surfactants has been shown to negatively impact their antimicrobial function. It was hypothesized that the phosphatidylglycerol component of surfactant was inhibiting AMP function and that an exogenous surfactant, with a reduced phosphatidylglycerol composition would increase peptide mediated killing at a distal site. To better understand how surfactant lipids interacted with CATH-2 and affected its function, isothermal titration calorimetry and solid-state nuclear magnetic resonance spectroscopy as well as bac...
    Amyloid self‐assembly of islet amyloid polypeptide (IAPP) is linked to pancreatic inflammation, β‐cell degeneration, and the pathogenesis of type 2 diabetes (T2D). The multifunctional host‐defence peptides (HDPs) cathelicidins play... more
    Amyloid self‐assembly of islet amyloid polypeptide (IAPP) is linked to pancreatic inflammation, β‐cell degeneration, and the pathogenesis of type 2 diabetes (T2D). The multifunctional host‐defence peptides (HDPs) cathelicidins play crucial roles in inflammation. Here, we show that the antimicrobial and immunomodulatory polypeptide human cathelicidin LL‐37 binds IAPP with nanomolar affinity and effectively suppresses its amyloid self‐assembly and related pancreatic β‐cell damage in vitro. In addition, we identify key LL‐37 segments that mediate its interaction with IAPP. Our results suggest a possible protective role for LL‐37 in T2D pathogenesis and offer a molecular basis for the design of LL‐37‐derived peptides that combine antimicrobial, immunomodulatory, and T2D‐related anti‐amyloid functions as promising candidates for multifunctional drugs.
    Apart from their role in the immune defence against pathogens evidence of a role of antimicrobial peptides (AMPs) in autoimmune diseases has accumulated in the past years. The aim of this project was to examine the functional impact of... more
    Apart from their role in the immune defence against pathogens evidence of a role of antimicrobial peptides (AMPs) in autoimmune diseases has accumulated in the past years. The aim of this project was to examine the functional impact of the human cathelicidin LL-37 and the mouse cathelicidin-related AMP (CRAMP) on the pathogenesis of lupus and arthritis. Serum LL-37 and anti-LL-37 levels were measured by ELISA in healthy donors and patients with Systemic Lupus Erythematosus (SLE) and Rheumatoid arthritis (RA). Pristane-induced lupus was induced in female wild type (WT) and cathelicidin-deficient (CRAMP-/-) mice. Serum levels of anti-Sm/RNP, anti-dsDNA, and anti-histone were determined via ELISA, cytokines in sera and peritoneal lavages were measured via Multiplex. Expression of Interferon I stimulated genes (ISG) was determined by real-time PCR. Collagen-induced arthritis (CIA) was induced in male WT and CRAMP-/- mice and arthritis severity was visually scored and analysed histomorph...
    Research Interests:
    Background Alzheimer’s disease (AD) is the most common neurodegenerative disease ultimately manifesting as clinical dementia. Despite considerable effort and ample experimental data, the role of neuroinflammation related to systemic... more
    Background Alzheimer’s disease (AD) is the most common neurodegenerative disease ultimately manifesting as clinical dementia. Despite considerable effort and ample experimental data, the role of neuroinflammation related to systemic inflammation is still unsettled. While the implication of microglia is well recognized, the exact contribution of peripheral monocytes/macrophages is still largely unknown, especially concerning their role in the various stages of AD. Objectives AD develops over decades and its clinical manifestation is preceded by subjective memory complaints (SMC) and mild cognitive impairment (MCI); thus, the question arises how the peripheral innate immune response changes with the progression of the disease. Therefore, to further investigate the roles of monocytes/macrophages in the progression of AD we assessed their phenotypes and functions in patients at SMC, MCI and AD stages and compared them with cognitively healthy controls. We also conceptualised an idealise...
    Many organisms rely on antimicrobial peptides (AMPs) as a first line of defense against pathogens. In general, most AMPs are thought to kill bacteria by binding to and disrupting cell membranes. However, certain AMPs instead appear to... more
    Many organisms rely on antimicrobial peptides (AMPs) as a first line of defense against pathogens. In general, most AMPs are thought to kill bacteria by binding to and disrupting cell membranes. However, certain AMPs instead appear to inhibit biomacromolecule synthesis, while causing less membrane damage. Despite an unclear understanding of mechanism(s), there is considerable interest in mimicking AMPs with stable, synthetic molecules. Antimicrobial N-substituted glycine (peptoid) oligomers ("ampetoids") are structural, functional and mechanistic analogs of helical, cationic AMPs, which offer broad-spectrum antibacterial activity and better therapeutic potential than peptides. Here, we show through quantitative studies of membrane permeabilization, electron microscopy, and soft X-ray tomography that both AMPs and ampetoids trigger extensive and rapid non-specific aggregation of intracellular biomacromolecules that correlates with microbial death. We present data demonstrat...
    <p>LC<sub>50</sub> means lethal concentrations causing 50% of the cell death. The maximum peptoid and peptide concentration tested was 100 µM. Cell viability was measured via MTS assay in cells treated with compounds for... more
    <p>LC<sub>50</sub> means lethal concentrations causing 50% of the cell death. The maximum peptoid and peptide concentration tested was 100 µM. Cell viability was measured via MTS assay in cells treated with compounds for 72 h, and LC<sub>50</sub> of peptoids was derived from peptoids' viability curves. HC<sub>10</sub> **, concentration causing 10% hemolysis of human red blood cells, all the numbers were cited from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090397#pone.0090397-Czyzewski2" target="_blank">[25]</a>. “—”, data not measured. Peptoids labeled with asterisk have been reported previously to possess antimicrobial activities <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090397#pone.0090397-Patch1" target="_blank">[23]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090397#pone.0090397-Chongsiriwatana1" target="_blank">[24]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0090397#pone.0090397-Czyzewski2" target="_blank">[25]</a>.</p
    DNA molecules cannot be separated by free-solution electrophoresis [1], because in free solution the ratio of net molecular charge to friction coefficient (the electrophoretic mobility) is nearly equal for all DNA molecules regardless of... more
    DNA molecules cannot be separated by free-solution electrophoresis [1], because in free solution the ratio of net molecular charge to friction coefficient (the electrophoretic mobility) is nearly equal for all DNA molecules regardless of their chain length [2, 3]. However, it was discovered in 1967 [4] that if electrophoresis is performed within a properly-formulated slab gel matrix (e.g., agarose or crosslinked Polyacrylamide), it is possible to separate differently-sized DNA molecules into distinct zones, where electrophoretic mobility is a decreasing function of DNA chain length. In addition to providing size-based separation of DNA, the crosslinked Polyacrylamide or agarose network of a slab gel serves as a physical support during electrophoresis, substantially reducing diffusion and convection of migrating DNA molecules. This allows the separated zones of differently-sized DNA molecules to remain relatively sharp, if gel formulation and electrophoresis conditions are chosen properly.
    An optimized microchip electrophoresis system for mutation detection by tandem SSCP and heteroduplex analysis for p53 gene exons 5–9 With the complete sequencing of the human genome, there is a growing need for rapid, highly sensitive... more
    An optimized microchip electrophoresis system for mutation detection by tandem SSCP and heteroduplex analysis for p53 gene exons 5–9 With the complete sequencing of the human genome, there is a growing need for rapid, highly sensitive genetic mutation detection methods suitable for clinical implementa-tion. DNA-based diagnostics such as single-strand conformational polymorphism (SSCP) and heteroduplex analysis (HA) are commonly used in research laboratories to screen for mutations, but the slab gel electrophoresis (SGE) format is ill-suited for routine clinical use. The translation of these assays from SGE to microfluidic chips offers significant speed, cost, and sensitivity advantages; however, numerous param-eters must be optimized to provide highly sensitive mutation detection. Here we pres-ent a methodical study of system parameters including polymer matrix, wall coating, analysis temperature, and electric field strengths on the effectiveness of mutation detection by tandem SSCP...
    COVID-19 is characterized by hyperactivation by inflammatory cytokines and recruitment of macrophages, neutrophils, and other immune cells, all hallmarks of a strong inflammatory response that can lead to severe complications and... more
    COVID-19 is characterized by hyperactivation by inflammatory cytokines and recruitment of macrophages, neutrophils, and other immune cells, all hallmarks of a strong inflammatory response that can lead to severe complications and multi-organ damage. Mortality in COVID-19 patients is associated with a high prevalence of neutrophil extracellular trap (NET) formation and microthrombosis that are exacerbated by hyperglycemia, diabetes, and old age. SARS-CoV-2 infection in humans and non-human primates have revealed long-term neurological consequences of COVID-19, possibly concomitant with the formation of Lewy bodies in the brain and invasion of the nervous system via the olfactory bulb. In this paper, we review the relevance of the human cathelicidin LL-37 in SARS-CoV-2 infections. LL-37 is an immunomodulatory, host defense peptide with direct anti-SARS-CoV-2 activity, and pleiotropic effects on the inflammatory response, neovascularization, Lewy body formation, and pancreatic islet ce...
    This article reviews research results and ideas presented at a special symposium at the International Association of Gerontology and Geriatrics (IAGG) Congress held in July 2017 in San Francisco. Five researchers presented their results... more
    This article reviews research results and ideas presented at a special symposium at the International Association of Gerontology and Geriatrics (IAGG) Congress held in July 2017 in San Francisco. Five researchers presented their results related to infection and Alzheimer\u27s disease (AD). Prof. Itzhaki presented her work on the role of viruses, specifically HSV-1, in the pathogenesis of AD. She maintains that although it is true that most people harbor HSV-1 infection, either latent or active, nonetheless aspects of herpes infection can play a role in the pathogenesis of AD, based on extensive experimental evidence from AD brains and infected cell cultures. Dr. Miklossy presented research on the high prevalence of bacterial infections that correlate with AD, specifically spirochete infections, which have been known for a century to be a significant cause of dementia (e.g., in syphilis). She demonstrated how spirochetes drive senile plaque formation, which are in fact biofilms. Prof...
    Lipid composition greatly affects the in vitro surface activity of lung surfactant protein mimics

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