Rebecca Howell

Bio: Rebecca Howell is an academic researcher from Yale University. The author has contributed to research in topics: Asialoglycoprotein receptor & Neutrophil extracellular traps. The author has an hindex of 2, co-authored 4 publications receiving 10 citations.

Bifunctional small molecules that mediate the degradation of extracellular proteins.

Abstract: Targeted protein degradation (TPD) has emerged as a promising therapeutic strategy. Most TPD technologies use the ubiquitin-proteasome system, and are therefore limited to targeting intracellular proteins. To address this limitation, we developed a class of modular, bifunctional synthetic molecules called MoDE-As (molecular degraders of extracellular proteins through the asialoglycoprotein receptor (ASGPR)), which mediate the degradation of extracellular proteins. MoDE-A molecules mediate the formation of a ternary complex between a target protein and ASGPR on hepatocytes. The target protein is then endocytosed and degraded by lysosomal proteases. We demonstrated the modularity of the MoDE-A technology by synthesizing molecules that induce depletion of both antibody and proinflammatory cytokine proteins. These data show experimental evidence that nonproteinogenic, synthetic molecules can enable TPD of extracellular proteins in vitro and in vivo. We believe that TPD mediated by the MoDE-A technology will have widespread applications for disease treatment.

Multi-site Validation of a SARS-CoV-2 IgG/IgM Rapid Antibody Detection Kit

Abstract: Deaths from coronavirus disease (COVID-19) have exceeded 300,000 persons globally, calling for rapid development of mobile diagnostics that can assay widespread prevalence and infection rates. Data provided in this study supports the utility of a newly-designed lateral flow immunoassay (LFA) for detecting SARS-CoV-2 IgM and IgG antibodies. We employed a clinical cohort of 1,892 SARS-CoV-2 patients and controls, including individuals diagnosed by RT-qPCR at Yale New Haven Hospital, The First Affiliated Hospital of Anhui Medical University, the Chinese Center for Disease Control and Prevention of Hefei City (Hefei CDC), Anhui Province (Anhui Province CDC), and Fuyang City (Fuyang CDC). The LFA studied here detects SARS-CoV-2 IgM and IgG antibodies with a specificity of 97.9-100% for IgM, 99.7-100% for IgG, and sensitivities ranging from 94.1-100% for patients >14-days post symptom onset. Sensitivity decreases in patients

Quantification of bronchoalveolar neutrophil extracellular traps and phagocytosis in murine pneumonia

Abstract: The past two decades have witnessed a resurgence in neutrophil research, inspired in part by the discovery of neutrophil extracellular traps (NETs) and their myriad roles in health and disease. Wit...

Fluorescent stem peptide mimics: In situ probes for peptidoglycan crosslinking.

Abstract: Understanding the mechanisms of bacterial cell wall synthesis is essential for microbiology and medicine alike. A key step in this process is peptidoglycan crosslinking, which confers mechanical strength to the cell wall and represents a target for numerous classes of antibiotics. However, the biology of crosslinking remains poorly understood due to a lack of tools for studying the reaction in vivo. Recently, we developed a class of synthetic probes called fluorescent stem peptide mimics (FSPMs) that meet this need, allowing quantification and localization of crosslinking activity in live bacteria. We have utilized FSPMs to describe novel aspects of peptidoglycan synthesis in the human pathogen, Staphylococcus aureus. To enable wider use of our methodology, we provide detailed protocols herein for the synthesis of FSPMs, labeling of live bacteria, and evaluation of crosslinking by flow cytometry and super-resolution microscopy. We believe that FSPMs, together with complementary biosynthetic probes and traditional bacteriologic methods, will help to advance our understanding of peptidoglycan biology and accelerate the search for new antibiotics.

Infectious Diseases Society of America Guidelines on the Diagnosis of COVID-19:Serologic Testing.

Abstract: Background The availability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologic testing has rapidly increased. Current assays use a variety of technologies, measure different classes of immunoglobulin or immunoglobulin combinations and detect antibodies directed against different portions of the virus. The overall accuracy of these tests, however, has not been well-defined. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the coronavirus disease 2019 (COVID-19) serology literature and construct best practice guidance related to SARS-CoV-2 serologic testing. This guideline is the fourth in a series of rapid, frequently updated COVID-19 guidelines developed by IDSA. Objective IDSA's goal was to develop evidence-based recommendations that assist clinicians, clinical laboratories, patients and policymakers in decisions related to the optimal use of SARS-CoV-2 serologic tests in a variety of settings. We also highlight important unmet research needs pertaining to the use of anti-SARS-CoV-2 antibody tests for diagnosis, public health surveillance, vaccine development and the selection of convalescent plasma donors. Methods A multidisciplinary panel of infectious diseases clinicians, clinical microbiologists and experts in systematic literature review identified and prioritized clinical questions related to the use of SARS-CoV-2 serologic tests. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. Results The panel agreed on eight diagnostic recommendations. Conclusions Information on the clinical performance and utility of SARS-CoV-2 serologic tests are rapidly emerging. Based on available evidence, detection of anti-SARS-CoV-2 antibodies may be useful for confirming the presence of current or past infection in selected situations. The panel identified three potential indications for serologic testing including: 1) evaluation of patients with a high clinical suspicion for COVID-19 when molecular diagnostic testing is negative and at least two weeks have passed since symptom onset; 2) assessment of multisystem inflammatory syndrome in children; and 3) for conducting serosurveillance studies. The certainty of available evidence supporting the use of serology for either diagnosis or epidemiology was, however, graded as very low to moderate.

β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium.

Abstract: The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.

Emerging targeted protein degradation tools for innovative drug discovery: From classical PROTACs to the novel and beyond.

Abstract: Targeted protein degradation technology has evolved a brand-new therapeutic modality from an innovative drug discovery perspective. Though the classical PROTACs has pioneered the way for protein degraders, certain inherent defects such as poor druggability, uncontrollable catalysis caused off-targets, and limited E3 ubiquitin ligases available constitute obstacles that impede further advances. Recent medicinal chemists have preferred to investigate a type of optimized degraders beyond the classical PROTACs, bypassing such disadvantages to better facilitate targeted protein degradation. In this perspective, we comprehensively spotlighted the emerging approaches and techniques applied to the targeted protein degradation, specifically the PROTACs-derived strategies and other alternatives to realize protein degradation via proteasome or lysosome. Besides, contemporary confronted opportunities as well as challenges were further analyzed, with the aim to guide future discovery of novel protein degraders.

Emerging degrader technologies engaging lysosomal pathways

Abstract: Targeted protein degradation (TPD) provides unprecedented opportunities for drug discovery. While the proteolysis-targeting chimera (PROTAC) technology has already entered clinical trials and changed the landscape of small-molecule drugs, new degrader technologies harnessing alternative degradation machineries, especially lysosomal pathways, have emerged and broadened the spectrum of degradable targets. We have recently proposed the concept of autophagy-tethering compounds (ATTECs) that hijack the autophagy protein microtubule-associated protein 1A/1B light chain 3 (LC3) for targeted degradation. Other groups also reported degrader technologies engaging lysosomal pathways through different mechanisms including AUTACs, AUTOTACs, LYTACs and MoDE-As. In this review, we analyse and discuss ATTECs along with other lysosomal-relevant degrader technologies. Finally, we will briefly summarize the current status of these degrader technologies and envision possible future studies.