Biology subjects

Loffredo, M.

Publications and source records attributed to Loffredo, M..

3 recordsLinked to original sources

bioRxiv2026

Regio-selective sulfation of heparin mimicking polymers defines in vivo activity

Heparin, a naturally derived glycosaminoglycan, is the most commonly used anti-thromboembolic in the world. However, the biological origin of heparin inherently results in batch-to-batch variability, large dispersity indexes, and potential contamination, leading to inconsistent activity and patient-dependent dose-response. As such, new synthetic anticoagulants are of keen interest, particularly those that mimic heparin while being amenable to alterations in polymer structure and composition for performance optimization. Herein, we report the strategy, synthesis, and evaluation of well-defined, regioselectively functionalized di-sulfated polyamidosaccharides (disulPASs) including exploration of the structure-function relationship of molecular weight and sulfation density on anticoagulant activity. Polymerization of an orthogonally protected y-lactam monomer via anionic ring-opening, followed by selective deprotection and sulfation reactions affords disulPAS. Similar to heparin, disulPASs elongate clotting time through the intrinsic and extrinsic pathways, showing molecular weight and dose-dependent responses in clotting time; are non-cytotoxic and non-hemolytic, partially neutralized by protamine sulfate, and unlike heparin, are not degraded by heparinases. As compared to less sulfated and randomly sulfated iterations of PAS, disulPAS performs superiorly, with in vitro and in vivo clotting activity most similar to native heparin.

bioengineering↗

bioRxiv2024

Tunable Universal OR-gated CAR T cells for AML

Abstract/SummaryAcute myeloid leukemia (AML) is a hematopoietic malignancy characterized by antigen heterogeneity and poor prognosis. A potential therapeutic approach to address this heterogeneity is targeting multiple surface antigens to prevent antigen escape and relapse. Chimeric antigen receptor (CAR) T cells are an adoptive cell therapy that have demonstrated remarkable clinical success in the treatment of B cell malignancies, and many efforts are underway to adapt them to myeloid malignancies. To tackle the heterogeneity of AML, logically targeting multiple antigens through an "A OR B" gated CAR circuit would be desirable. Here we combined FLT3 antigen targeting with the well characterized CD33 myeloid marker as a combinatorial OR gate approach using our split, universal, programmable (SUPRA) CAR platform. The split platform affords tunability over activation levels and multiplexed targeting that cannot be achieved through a tandem bispecific approach. We systematically characterized the specificity and sensitivity of different SUPRA CAR adapters against each target individually and in combination against a panel of target cell lines. Our results demonstrate that this CAR system can effectively target two antigens with equivalent efficacy to conventional CARs while reducing the engineering burden associated with designing CAR T cells against multiple antigens. Furthermore, we can characterize an effective dose range where off-target cytotoxicity against hematopoietic stem and progenitor cells is minimized. With the recent clinical advances in universal CAR designs, our SUPRA OR gate has the potential to provide an effective and safer solution to treating AML.

synthetic biology↗

bioRxiv2020

The Effect Of Famotidine On SARS-CoV-2 Proteases And Virus Replication

The lack of coronavirus-specific antiviral drugs has instigated multiple drug repurposing studies to redirect previously approved medicines for the treatment of SARS-CoV-2, the coronavirus behind the ongoing COVID-19 pandemic. A recent, large-scale, retrospective clinical study showed that famotidine, when administered at a high dose to hospitalized COVID-19 patients, reduced the rates of intubation and mortality. A separate, patient-reported study associated famotidine use with improvements in mild to moderate symptoms such as cough and shortness of breath. While a prospective, multi-center clinical study is ongoing, two parallel in silico studies have proposed one of the two SARS-CoV-2 proteases, 3CLpro or PLpro, as potential molecular targets of famotidine activity; however, this remains to be experimentally validated. In this report, we systematically analyzed the effect of famotidine on viral proteases and virus replication. Leveraging a series of biophysical and enzymatic assays, we show that famotidine neither binds with nor inhibits the functions of 3CLpro and PLpro. Similarly, no direct antiviral activity of famotidine was observed at concentrations of up to 200 M, when tested against SARS-CoV-2 in two different cell lines, including a human cell line originating from lungs, a primary target of COVID-19. These results rule out famotidine as a direct-acting inhibitor of SARS-CoV-2 replication and warrant further investigation of its molecular mechanism of action in the context of COVID-19.

pharmacology and toxicology↗