Rationally Designed Peptoid Inhibitors of Amyloid-ß Oligomerization.

While plaques comprised of fibrillar Aß aggregates are hallmarks of Alzheimer's disease, soluble Aß oligomers present higher neurotoxicity. Thus, one therapeutic approach is to prevent the formation of Aß oligomers and reduce their associated harmful effects. We have proposed a peptoid mimic of the Aß hydrophobic KLVFF core as an ideal candidate aggregation inhibitor due to its ability to evade proteolytic degradation via repositioning of the side chain from the α-carbon to the amide nitrogen. This peptoid, JPT1, utilizes chiral sidechains to achieve a helical structure, while C-terminal addition of two phenylalanine residues places aromatic groups on two sides of the helix with spacing designed to facilitate interaction with amyloid ß-sheet structure. We have previously shown that JPT1 modulates Aß fibril formation. Here, we demonstrate that JPT1 also modulates Aß oligomerization, and we explore the role of the charge on the linker between the KLVFF mimic and the extended aromatic residues. Additionally, we demonstrate that peptoid-induced changes in Aß oligomerization correlate with attenuation of oligomer-induced nuclear factor-κB activation in SH-SY5Y human neuroblastoma cells. These findings support the therapeutic potential of peptoids to target early stages of Aß aggregation and impact the associated Aß-induced cellular response.

Modulating the RAGE-Induced Inflammatory Response: Peptoids as RAGE Antagonists.

While the primary pathology of Alzheimer's disease (AD) is defined by brain deposition of amyloid-ß (Aß) plaques and tau neurofibrillary tangles, chronic inflammation has emerged as an important factor in AD etiology. Upregulated cell surface expression of the receptor for advanced glycation end-products (RAGE), a key receptor of innate immune response, is reported in AD. In parallel, RAGE ligands, including Aß aggregates, HMGB1, and S100B, are elevated in AD brain. Activation of RAGE by these ligands triggers release of inflammatory cytokines and upregulates cell surface RAGE. Despite such observation, there are currently no therapeutics that target RAGE for treatment of AD-associated neuroinflammation. Peptoids, a novel class of potential AD therapeutics, display low toxicity, facile blood-brain barrier permeability, and resistance to proteolytic degradation. In the current study, peptoids were designed to mimic Aß, a ligand that binds the V-domain of RAGE, and curtail RAGE inflammatory activation. We reveal the nanomolar binding capability of peptoids JPT1 and JPT1a to RAGE and demonstrate their ability to attenuate lipopolysaccharide-induced pro-inflammatory cytokine production as well as upregulation of RAGE cell surface expression. These results support RAGE antagonist peptoid-based mimics as a prospective therapeutic strategy to counter neuroinflammation in AD and other neurodegenerative diseases.

Cysteine-rich granulin-3 rapidly promotes amyloid-ß fibrils in both redox states.

Granulins (GRNs 1-7) are cysteine-rich proteolytic products of progranulin (PGRN) that have recently been implicated in neurodegenerative diseases including frontotemporal dementia (FTD) and Alzheimer's disease (AD). Their precise mechanism in these pathologies remains uncertain, but both inflammatory and lysosomal roles have been observed for GRNs. Among the seven GRNs, GRN-3 is well characterized and is implicated within the context of FTD. However, the relationship between GRN-3 and amyloid-ß (Aß), a protein relevant in AD pathology, has not yet been explored. To gain insight into this mechanism, we investigated the effect of both oxidized and reduced GRN-3 on Aß aggregation and found that both GRN-3 (oxidized) and rGRN-3 (reduced) bind to monomeric and oligomeric Aß42 to promote rapid fibril formation with subtle rate differences. As low molecular weight oligomers of Aß are well-established neurotoxins, rapid promotion of fibrils by GRN-3 mitigates Aß42-induced cellular apoptosis. These data provide valuable insights in understanding GRN-3's ability to modulate Aß-induced toxicity under redox control and presents a new perspective toward AD pathology. These results also prompt further investigation into the role(s) of other GRNs in AD pathogenesis.

Impact of an emergency medicine pharmacist on empiric antibiotic prescribing for pneumonia and intra-abdominal infections.

PURPOSE: It is critical to engage ED providers in antimicrobial stewardship programs (ASP). Emergency medicine pharmacists (EMPs) play an important role in ASP by working with providers to choose empiric antimicrobials. This study aimed to determine the impact of an EMP on appropriate empiric antibiotic prescribing for community-acquired pneumonia (CAP) and intra-abdominal infections (CA-IAI). METHODS: A retrospective cohort study was conducted evaluating adult patients admitted with CAP or CA-IAI. The primary outcome of this study was to compare guideline-concordant empiric antibiotic prescribing when an EMP was present vs. absent. We also aimed to compare the impact of an EMP in an early-ASP vs. established-ASP. RESULTS: 320 patients were included in the study (EMP n = 185, no-EMP n = 135). Overall empiric antibiotic prescribing was more likely to be guideline-concordant when an EMP was present (78% vs. 61%, p = 0.001); this was true for both the CAP (95% vs. 79%, p = 0.005) and CA-IAI subgroups (62% vs. 44%, p = 0.025). Total guideline-concordant prescribing significantly increased between the early-ASP and established-ASP (60% vs. 82.5%, p < 0.001) and was more likely when an EMP was present (early-ASP: 68.3% vs. 45.8%, p = 0.005; established-ASP: 90.5% vs. 73.7%, p = 0.005). Patients receiving guideline-concordant antibiotics in the ED continued appropriate therapy upon admission 82.5% of the time vs. 18.8% if the ED antibiotic was inappropriate (p < 0.001). CONCLUSION: The presence of an EMP significantly improved guideline-concordant empiric antibiotic prescribing for CAP and CA-IAI in both an early and established ASP. Inpatient orders were more likely to be guideline-concordant if appropriate therapy was ordered in the ED.

Full-dose challenge of moderate, severe, and unknown beta-lactam allergies in the emergency department.

OBJECTIVE: This study aims to assess the outcome of challenging documented moderate, severe, or unknown beta-lactam allergies with full dose administration of a beta-lactam antibiotic in emergency department (ED) patients admitted for acute bacterial infection. METHODS: A single-center, retrospective, descriptive study of adult patients challenged with a full dose of beta-lactam in the ED from January 2021 to December 2022 was conducted. Included patients had at least one documented moderate, severe, or unknown beta-lactam allergy in the electronic medical record (EMR) without documentation of prior tolerance. Patient demographics, prior beta-lactam antibiotic reaction, beta-lactam administered in the ED, inpatient beta-lactam continuation, adverse drug reactions, and updates to allergy profiles were collected. Descriptive statistics for data analysis were performed using SPSS Version 22. RESULTS: Of the 184 ED encounters with full-dose beta-lactam challenges, five (2.7%) patients with documented moderate, severe, or unknown beta-lactam allergies experienced an allergic reaction after the challenge; one (0.5%) patient had an allergic reaction in the ED, and the remaining four (2.2%) occurred after admission. No anaphylactic reactions occurred. All allergic reactions were limited to mild rash or itching. Most patients (98.9%) were challenged with a cephalosporin. A beta-lactam was continued in 86.4% of cases, and the allergy profile was updated for future utilization in 73.4% of patients. CONCLUSIONS: This study suggests that full-dose challenge of moderate, severe, or unknown beta-lactam allergies can be safely accomplished in the ED. This approach avoids unnecessary penicillin allergy skin testing and reduces utilization of suboptimal alternative antibiotic regimens.

Feasibility evaluation to expand a collaborative practice agreement and discontinue antibiotics after an emergency department or urgent care visit.

PURPOSE: The impact of pharmacist-led culture follow-up programs for positive cultures is well established. The benefits and feasibility of evaluating negative cultures and deprescribing unnecessary antibiotics after emergency department (ED) and urgent care (UC) visits are unknown; therefore, this evaluation characterized the burden of negative urine cultures and chlamydia tests and estimated how many potential antibiotic days could be saved with deprescribing. METHODS: This retrospective, descriptive study evaluated patients discharged from an ED or UC location with a pharmacist-led culture follow-up program. The primary objective was to characterize the proportion of patients with a negative urine culture or chlamydia test where an opportunity would exist to deprescribe antibiotics at follow-up. Secondary endpoints included estimating the number of potential antibiotic days that could be saved, postvisit healthcare utilization, and documented adverse drug reactions (ADRs). RESULTS: For a 1-month period, pharmacists reviewed 398 cultures, of which 208 (52%) were urine cultures or chlamydia tests with negative results. Fifty patients (24%) with negative results had been prescribed empiric antibiotics. The median duration of antibiotic treatment was 7 days (interquartile range [IQR], 5-7 days), while the median time to culture finalization was 2 days (IQR, 1-2 days). There was an opportunity to save a median of 5 antibiotic days per patient. Thirty-two patients (15.3%) followed up with their primary care physician within 7 days; of these patients, 1 (0.05%) had their antibiotic prescription discontinued by the primary care physician. There were no documented ADRs. CONCLUSION: Expansion of pharmacist-led culture follow-up programs to deprescribe antibiotics for patients with negative cultures has the potential to save significant antibiotic exposure.

Pharmacist-led antimicrobial stewardship program in an urgent care setting.

PURPOSE: While many programs have demonstrated pharmacist-led antimicrobial stewardship successes in inpatient and emergency department (ED) settings, there is a paucity of literature exploring these initiatives in urgent care (UC) sites. This study aimed to determine the impact of implementing a pharmacist-led antimicrobial stewardship program (ASP) in the UC setting. METHODS: A retrospective quasi-experimental study was conducted evaluating UC patients with positive urine or wound cultures following discharge. A collaborative practice agreement was implemented in 2015 allowing for pharmacist-led UC culture follow-up via a stewardship-focused protocol. The primary outcome of this study was to compare guideline-concordant antibiotic prescribing between the pre-ASP and post-ASP groups. Secondary outcomes included comparing the number of patients who required follow-up, time to follow-up, UC or ED revisits within 72 hours, and hospital admission within 30 days between groups. RESULTS: A total of 300 patients were included in the study (pre-ASP, n = 150; post-ASP, n = 150). Total guideline-concordant prescribing for all diagnoses was significantly improved in the post-ASP group (pre-ASP, 41.3% versus post-ASP 53.3%, p = 0.037). Additionally, guideline-concordant antibiotic selection improved in the post-ASP group (pre-ASP, 51% versus post-ASP, 68%, p = 0.01). Follow-up was required for 27 (18%) patients in the pre-ASP group compared with 16 (10.7%) in the post-ASP group (p = 0.07). Median time to follow-up call was longer in the post-ASP group (38 versus 71 hours, p < 0.001). There were no differences in UC and ED revisits within 72 hours (p = 1.0) or hospital admissions within 30 days (p = 0.723). CONCLUSION: A pharmacist-led urgent care ASP was associated with significantly improved guideline-concordant antimicrobial prescribing.

Fully reduced granulin-B is intrinsically disordered and displays concentration-dependent dynamics.

Granulins (Grns) are a family of small, cysteine-rich proteins that are generated upon proteolytic cleavage of their precursor, progranulin (Pgrn). All seven Grns (A-G) contain 12 conserved cysteines that form 6 intramolecular disulfide bonds, rendering this family of proteins unique. Grns are known to play multi-functional roles, including wound healing, embryonic growth, and inflammation and are implicated in neurodegenerative diseases. Despite their manifold functions, there exists a dearth of information regarding their structure-function relationship. Here, we sought to establish the role of disulfide bonds in promoting structure by investigating the fully reduced GrnB (rGrnB). We report that monomeric rGrnB is an intrinsically disordered protein (IDP) at low concentrations. rGrnB undergoes dimerization at higher concentrations to form a fuzzy complex without a net gain in the structure-a behavior increasingly identified as a hallmark of some IDPs. Interestingly, we show that rGrnB is also able to activate NF-κB in human neuroblastoma cells in a concentration-dependent manner. This activation correlates with the observed monomer-dimer dynamics. Collectively, the presented data establish that the intrinsic disorder of rGrnB governs conformational dynamics within the reduced form of the protein, and suggest that the overall structure of Grns could be entirely dictated by disulfide bonds.