Passivating the Background of Living Microbes with a Zwitterionic Peptide for Therapies

Living microbial therapies have been proposed as a course of action for a variety of diseases. However, problematic interactions between the host immune system and the microbial organism present significant clinical concerns. Previously, we developed a genetically encoded superhydrophilic zwitterionic peptide, termed EKP, to mimic low-immunogenic zwitterionic materials, which have been used for the chemical modification of biologics such as protein and nucleic acid drugs to increase their in vivo circulation time and reduce their immunogenicity. Herein, we demonstrate the protective effects of the EKP polypeptide genetically cloaking the surface of Saccharomyces cerevisiae as a model microbe in both in vitro and in vivo systems. First, we show that EKP peptide cloaking suppresses the interactions between yeast cells and their specific antibodies, thereby illustrating its cloaking behavior. Then, we examine the in vitro interactions between EKP peptide surface cloaked yeast cells and murine macrophage cells, which exhibit phagocytotic behavior in the presence of foreign microbes. Our results indicate that EKP cloaking suppresses macrophage interactions and thus reduces phagocytosis. Furthermore, EKP cloaked yeast cells demonstrate a prolonged circulation time in mice in vivo.

Ocular manifestations of CHARGE syndrome in a pediatric cohort with genotype/phenotype analysis

CHARGE syndrome is a rare multi-system condition associated with CHD7 variants. However, ocular manifestations and particularly ophthalmic genotype-phenotype associations, are not well-studied. This study evaluated ocular manifestations and genotype-phenotype associations in pediatric patients with CHARGE syndrome. A retrospective chart review included pediatric patients under 20 years-old with clinical diagnosis of CHARGE syndrome and documented ophthalmic examination. Demographics, genetic testing, and ocular findings were collected. Comprehensive literature review enhanced the genotype-phenotype analysis. Forty-two patients (20 male) underwent eye examination at an average age of 9.45 ± 6.52 years-old. Thirty-nine (93%) had ophthalmic manifestations in at least one eye. Optic nerve/chorioretinal colobomas were most common (38 patients), followed by microphthalmia (13), cataract (6), and iris colobomas (4). Extraocular findings included strabismus (32 patients), nasolacrimal duct obstructions (11, 5 with punctal agenesis), and cranial nerve VII palsy (10). Genotype-phenotype analyses (27 patients) showed variability in ocular phenotypes without association to location or variant types. Splicing (10 patients) and frameshift (10) variants were most prevalent. Patients with CHARGE syndrome may present with a myriad of ophthalmic manifestations. There is limited data regarding genotype-phenotype correlations and additional studies are needed.

Extracellular vesicles incorporating retrovirus-like capsids for the enhanced packaging and systemic delivery of mRNA into neurons

The blood-brain barrier (BBB) restricts the systemic delivery of messenger RNAs (mRNAs) into diseased neurons. Although leucocyte-derived extracellular vesicles (EVs) can cross the BBB at inflammatory sites, it is difficult to efficiently load long mRNAs into the EVs and to enhance their neuronal uptake. Here we show that the packaging of mRNA into leucocyte-derived EVs and the endocytosis of the EVs by neurons can be enhanced by engineering leucocytes to produce EVs that incorporate retrovirus-like mRNA-packaging capsids. We transfected immortalized and primary bone-marrow-derived leucocytes with DNA or RNA encoding the capsid-forming activity-regulated cytoskeleton-associated (Arc) protein as well as capsid-stabilizing Arc 5'-untranslated-region RNA elements. These engineered EVs inherit endothelial adhesion molecules from donor leukocytes, recruit endogenous enveloping proteins to their surface, cross the BBB, and enter the neurons in neuro-inflammatory sites. Produced from self-derived donor leukocytes, the EVs are immunologically inert, and enhanced the neuronal uptake of the packaged mRNA in a mouse model of low-grade chronic neuro-inflammation.

Hidden hydrophobicity impacts polymer immunogenicity

Antibodies against poly(ethylene glycol) (PEG) have been found to be the culprit of side reactions and efficacy loss of a number of PEGylated drugs. Fundamental mechanisms of PEG immunogenicity and design principles for PEG alternatives still have not been fully explored. By using hydrophobic interaction chromatography (HIC) under varied salt conditions, we reveal the "hidden" hydrophobicity of those polymers which are generally considered as hydrophilic. A correlation between the hidden hydrophobicity of a polymer and its polymer immunogenicity is observed when this polymer is conjugated with an immunogenic protein. Such a correlation of hidden hydrophobicity vs. immunogenicity for a polymer also applies to corresponding polymer-protein conjugates. Atomistic molecular dynamics (MD) simulation results show a similar trend. Based on polyzwitterion modification and with this HIC technique, we are able to produce extremely low-immunogenic protein conjugates as their hydrophilicity is pushed to the limit and their hydrophobicity is eliminated, breaking the current barriers of eliminating anti-drug and anti-polymer antibodies.

Impacts of a Zwitterionic Peptide on its Fusion Protein

Therapeutic proteins frequently need to be modified with high-molecular-weight molecules to improve their pharmacokinetic properties. The genetic linkage of therapeutic proteins to a high-molecular-weight zwitterionic peptide, termed EKP, offers a promising approach. As with any protein modification, EKP could impact the structural behavior and receptor binding properties of the linked therapeutic protein, thereby altering its bioactivity. To evaluate the effects of EKP on therapeutic proteins, we study the receptor binding properties of high-molecular-weight EKP linked to the growth colony-stimulating factor (GCSF) using the genetically based yeast display platform. We find that yeast-displayed EKP-GCSF and GCSF exhibits similar binding to its receptor GCSF-R, suggesting that EKP does not hinder receptor binding. Furthermore, yeast-displayed EKP-GCSF demonstrates protection against thermal denaturation compared to GCSF. Similarly, to study the structural effects of EKP on GCSF, we employ in silico modeling using alphaFold2 in conjunction with molecular dynamics (MD) simulations. Likewise, in silico modeling reveals that EKP does not alter the structural behavior of GCSF. Finally, we demonstrate the functional benefits of EKP, by which the EKP-GCSF fusion protein produced in Escherichia coli exhibits improved pharmacokinetics and prolonged bioactivity in vivo.

Motif-based zwitterionic peptides impact their structure and immunogenicity

The linkage of zwitterionic peptides containing alternating glutamic acid (E) and lysine (K) amino acids exhibits protective effects on protein drugs due to their high hydration capacity. Previously, short EK peptides covering the surface of a protein drug showed significant protective effects and low immunogenicity. However, for high-molecular-weight single-chain (HMWSC) zwitterionic peptides, the incorporation of structure-disrupting amino acids such as proline (P), serine (S), and glycine (G) is necessary to improve their protective ability. Herein, we first probe the immunogenicity of eight EK-containing motif-based peptides, six of which incorporate structure-disrupting amino acids P, S, and G, linked to keyhole limpet hemocyanin (KLH). These studies uncover two sequence motifs, EKS and EKG, which show uniquely higher immunogenicity, while the other motifs, especially those containing P, exhibit lower immunogenicity. Additionally, the structure and dynamics of these sequence motifs are computationally modeled by Rosetta protein predictions and molecular dynamics (MD) simulations to predict properties of higher and lower immunogenicity peptides. These simulations revealed peptides with higher immunogenicity, namely EKS and EKG, exhibit regions of charge imbalance. Then, HMWSC zwitterionic sequences were linked to a typical protein drug, interferon-alpha 2a (IFN), which showed consistent immunogenic behaviors. Finally, epitope mapping and alanine scanning experiments using the serum collected from mice injected with HMWSC sequences also implicated a link between charge imbalance and peptide immunogenicity.

Structure breaking amino acids, P, S, and G, are incorporated into low immunogenic unstructured zwitterionic peptide fusion proteins. We find unique sequence motifs that exhibit charge balanced conformations and low immunogenicity.

Differential Susceptibility of Diverse Salix spp. to Melampsora americana and Melampsora paradoxa

Melampsora spp. willow rust is the most serious disease of shrub willow bioenergy production in the northeastern United States. Recent phylogenetic studies have identified several Melampsora spp. present on willow in the Northeast; however, in-depth understanding of Melampsora spp. host susceptibility remain unresolved. In this study, a panel of 82 rust isolates collected from the northeastern United States were genotyped via ribosomal DNA sequencing and a subset of these isolates were assayed for host susceptibility. This work revealed that Melampsora americana is the most prevalent species in the sampled geographic region and that there is potential for rust resistance breeding using the Salix spp. taxa assayed. Additionally, leaf morphology traits of these Salix spp. hosts were quantified for correlation analysis, revealing that trichome density and stomata density are possible contributors to resistance. This work provides foundational rust pathology information, which is crucial for M. americana resistance breeding.

De novo design of functional zwitterionic biomimetic material for immunomodulation

Superhydrophilic zwitterionic polymers are a class of nonfouling materials capable of effectively resisting any nonspecific interactions with biological systems. We designed here a functional zwitterionic polymer that achieves a trade-off between nonspecific interactions providing the nonfouling property and a specific interaction for bioactive functionality. Built from phosphoserine, an immune-signaling molecule in nature, this zwitterionic polymer exhibits both nonfouling and immunomodulatory properties. Its conjugation to uricase is shown to proactively eradicate all unwanted immune response, outperforming the zwitterionic polymers. On the other hand, this polymer could significantly prolong the half-life of protein drugs in vivo, overcoming the innate drawback of phosphoserine in inducing accelerated clearance. Our demonstration of a nonfouling zwitterionic material with built-in immunomodulatory functionality provides new insights into the fundamental design of biomaterials, as well as far-reaching implications for broad applications such as drug delivery, implants, and cell therapy.

Enhanced pulmonary systemic delivery of protein drugs via zwitterionic polymer conjugation

Pulmonary delivery of protein drugs into the systemic circulation is highly desirable as the lung provides a large absorption surface area and a more favorable environment for biologics compared to other delivery routes. However, pulmonary systemic delivery of proteins presents several challenges such as poor protein stability and limited bioavailability, especially for large proteins (molecular weight > 50 kDa), which exhibit an average bioavailability of 1% to 5% when delivered via the pulmonary route. Here, we demonstrated that with the conjugation of zwitterionic poly(carboxybetaine) (pCB) polymer, the bioavailability of organophosphate hydrolase (OPH) was significantly increased from 5% to 53%. OPH conjugated with pCB delivered through intubation-assisted intratracheal instillation (IAIS) into the lung exhibited improved pharmacokinetic properties and prophylactic efficacy against organophosphate poisoning, showing its application potential. Zwitterionic polymer conjugation provides the possibility for a favorable, non-invasive delivery of biological therapeutics into the systemic circulation.

A Chromatin-Mimetic Nanomedicine for Therapeutic Tolerance Induction

The undesirable immune response poses a life-threatening challenge to human health. It not only deteriorates the therapeutic performance of biologic drugs but also contributes to various diseases such as allergies and autoimmune diseases. Inspired by the role of chromatin in the maintenance of natural immune tolerance, here we report a DNA-protein polymeric nanocomplex that can mimic the tolerogenic function of chromatin and induce an immune tolerance to its protein cargos. We first proved that the chromatin-mimetic nanomedicine loaded with keyhole limpet hemocyanin (KLH), a highly immunogenic model protein, could elicit a durable antigen-specific immune tolerance to KLH lasting for at least five weeks in mice. Following the proof-of-concept study, we demonstrated that this nanomedicine could be applied to improve the safety and efficacy of a biologic drug, PEGylated uricase, by attenuating the relevant antibody (Ab) responses. Moreover, we also demonstrated that prophylactic treatments with this nanomedicine could tolerize the immune system with the allergen of ovalbumin (OVA) and thus inhibit the occurrence of airway inflammation in an OVA-induced allergic asthma murine model. Collectively, our work illustrates a nature-inspired concept of immune tolerance induction and establishes a useful tool to specifically suppress unwanted immune responses for therapeutic purposes.

Abstract OT2-04-01: An open label, phase II trial of continuous low-irradiance photodynamic therapy (CLIPT) using verteporfin for the treatment of cutaneous breast cancer metastases

Background

Cutaneous metastases occur in approximately 20% of patients (pts) with metastatic breast cancer (mBC) and can be highly symptomatic and distressing. Radiation therapy is frequently used, but progression often occurs quickly. Systemic therapies are also typically used, but also often result in limited benefit. Photodynamic therapy is a promising approach with encouraging results in small studies. Here we will evaluate a novel Continuous Low-Irradiance Photodynamic Therapy (CLIPT) system that emits 690nm LED via a handheld Power Pack attached to a single-use sterile Light Patch to deliver a total energy level of 20J/cm2. Verteporfin (Visudyne®) is a photosensitizer approved for ophthalmological use that, when combined with CLIPT, generates activated oxygen species which can destroy tumor cells with limited normal tissue reaction.

Methods

This open label, Phase 2 study will evaluate the efficacy and safety of CLIPT with verteporfin in 15 patients with cutaneous lesions from mBC. Patients will receive a single IV injection of Verteporfin on day 1. The 9x9cm Light Patch with an adhesive border is placed over the treatment site and attached to the CLIPT portable Power Pack. The patient turns the device on at home 6 hours after the Verteprofin injection and it automatically turns off after 24 hours. The patient then removes the Light Patch and returns to clinic on day 3. The primary endpoint is objective response rate (RR) at 3 weeks following CLIPT using a modified RECIST which accounts for nodular or diffuse plaque-like lesions. Response will be confirmed by independent dermatologist review. Secondary endpoints include RR at 2, 8 and 12 weeks, toxicity, and quality of life (using FACT-B and Brief Pain Inventory). A novel Participant Symptom Scale (PSS) will also be used in which the first 8 patients will list their most distressing symptoms from cutaneous metastases and score the severity of the symptoms from 1 to 10. The six most common symptoms among the first 8 patients will then be used in the PSS for the remaining 7 patients. The PSS will be assessed at baseline and at subsequent visits to explore any improvement in severity of symptoms after treatment with CLIPT. Patients who derive clinical benefit may be retreated up to 3 times to the same or different region. Eligible patients will have: cutaneous metastases from mBC with measurable disease by protocol defined modified RECIST 1.1, ≥ 1 line of prior systemic or local therapy for mBC, ≥ 14 days from prior systemic therapy or 60 days from radiation to target lesion, and no expectation for systemic therapy for ≥ 14 days after CLIPT. RR will be reported with 95% CI. With 15 patients, if ≥ 3 responses (RR ≥ 20%) are observed, the null hypothesis of RR ≤ 5% will be rejected. At the time of abstract submission, 4 patients have been accrued. Clinical Trials Reg: NCT02939274

Citation Format: Isakoff SJ, Rogers GS, Hill S, McMullen P, Habin KR, Chen ST, Bartenstein DW, Barry W, Overmoyer BA. An open label, phase II trial of continuous low-irradiance photodynamic therapy (CLIPT) using verteporfin for the treatment of cutaneous breast cancer metastases [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-04-01.

Applying 'omics technologies in chemicals risk assessment: Report of an ECETOC workshop

Prevailing knowledge gaps in linking specific molecular changes to apical outcomes and methodological uncertainties in the generation, storage, processing, and interpretation of 'omics data limit the application of 'omics technologies in regulatory toxicology. Against this background, the European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) convened a workshop Applying 'omics technologies in chemicals risk assessment that is reported herein. Ahead of the workshop, multi-expert teams drafted frameworks on best practices for (i) a Good-Laboratory Practice-like context for collecting, storing and curating 'omics data; (ii) the processing of 'omics data; and (iii) weight-of-evidence approaches for integrating 'omics data. The workshop participants confirmed the relevance of these Frameworks to facilitate the regulatory applicability and use of 'omics data, and the workshop discussions provided input for their further elaboration. Additionally, the key objective (iv) to establish approaches to connect 'omics perturbations to phenotypic alterations was addressed. Generally, it was considered promising to strive to link gene expression changes and pathway perturbations to the phenotype by mapping them to specific adverse outcome pathways. While further work is necessary before gene expression changes can be used to establish safe levels of substance exposure, the ECETOC workshop provided important incentives towards achieving this goal.

Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME

This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4α, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4α), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.

Modeling drug- and chemical-induced hepatotoxicity with systems biology approaches

We provide an overview of computational systems biology approaches as applied to the study of chemical- and drug-induced toxicity. The concept of “toxicity pathways” is described in the context of the 2007 US National Academies of Science report, “Toxicity testing in the 21st Century: A Vision and A Strategy.” Pathway mapping and modeling based on network biology concepts are a key component of the vision laid out in this report for a more biologically based analysis of dose-response behavior and the safety of chemicals and drugs. We focus on toxicity of the liver (hepatotoxicity) – a complex phenotypic response with contributions from a number of different cell types and biological processes. We describe three case studies of complementary multi-scale computational modeling approaches to understand perturbation of toxicity pathways in the human liver as a result of exposure to environmental contaminants and specific drugs. One approach involves development of a spatial, multicellular “virtual tissue” model of the liver lobule that combines molecular circuits in individual hepatocytes with cell–cell interactions and blood-mediated transport of toxicants through hepatic sinusoids, to enable quantitative, mechanistic prediction of hepatic dose-response for activation of the aryl hydrocarbon receptor toxicity pathway. Simultaneously, methods are being developing to extract quantitative maps of intracellular signaling and transcriptional regulatory networks perturbed by environmental contaminants, using a combination of gene expression and genome-wide protein-DNA interaction data. A predictive physiological model (DILIsym™) to understand drug-induced liver injury (DILI), the most common adverse event leading to termination of clinical development programs and regulatory actions on drugs, is also described. The model initially focuses on reactive metabolite-induced DILI in response to administration of acetaminophen, and spans multiple biological scales.

Prenatal care needs, availability, accessibility, use, and satisfaction: a comparison of military women within and outside the continental United States

This article presents the results of a survey distributed to military women within and outside the continental United States (CONUS and OCONUS) who had received prenatal care and delivered at one of six Army, Navy, or Air Force military facilities. This comparative descriptive study was undertaken to determine from the mothers' perspective (1) their needs, availability, accessibility, use, satisfaction, and preferences for prenatal care services, and (2) if prenatal care and birth outcomes were significantly different for CONUS versus OCONUS women. Both groups reported a high degree of satisfaction with services, clinics/offices, and health care staff. Significant group differences were reported in transportation, length of travel time, and cost of traveling, with the CONUS group reporting greater problems with each. For both groups, quality and consistency of health care were the two most important factors in their preference of provider. More than 20% of the mothers reported receiving no information on some of the common concerns of pregnancy. There were no significant group differences with regard to infant birth weight or length of hospital stay.

Exploration of facilitators and barriers to prenatal care among military women

Early and regular prenatal care has been shown to decrease the incidence of adverse pregnancy outcomes; however, little research has examined it experientially from the mother's perspective. The purpose of this qualitative study was to explore the experience of prenatal care from the military mother's perspective. Using purposive sampling, 16 women who had recently given birth were interviewed. The data were analyzed using a qualitative descriptive research methodology to elicit categories of substantive concepts, ideas, or themes. Data explored in this study included availability, use and satisfaction with prenatal care services, and barriers, preferences, and recommendations.

A guide to understanding informed consent

Anesthesia providers are expected to provide information to the patient during the preanesthesia interview that enables the patient to make informed choices. Adequate disclosure during the informed consent process ensures the equalization of the practitioner/patient relationship and the decision-making rights of the patient. Both certified registered nurse anesthetists (CRNAs) and anesthesiologists are not only legally required to provide information that will allow a patient to make an informed judgment about how to proceed with various anesthetic modalities but are also obligated by their standards of practice. This article informs the CRNA about the principles of informed consent so that they can better understand their role in the informed consent process.

Informed consent: an essential element of safe anesthesia practice

Generally, health care providers have viewed safety in terms of prevention of patient accidents. However, with the growth of patient consumerism and stress on quality improvement, the concept of "safety" has been expanded. This article examines the legal concept of informed consent and offers practical suggestions on increasing both patient and provider safety and improving quality of care. For reasons dictated by statute, case law, and professional ethics, informed consent should be part of the practice of every CRNA. With proper informed consent, misinformation, dissatisfaction, and subsequent legal action can be diminished. Information should be offered to the patient and family and reinforced with written educational materials and instructions. These procedures should be documented in the medical record to provide verification that the patient was informed of the risks and benefits and agreed to the procedure contemplated. Failure to do so could expose the CRNA to legal actions under legal theories that include not only negligence, but battery, and contract as well.