Development of Peptide Glucosyltransferase Inhibitors With Comprehensive Coverage Across Clostridioides difficile Toxin B Sub-Types - Article

Sep 30, 2026

Clostridioides difficile infection increasingly threatens clinical care as hypervirulent, antibiotic-resistant strains spread. Colitis and diarrhea result from toxin release, mainly TcdA and TcdB, so peptide inhibitors that block these toxins are a promising therapeutic option alone or alongside standard antibiotics. This study reports rational discovery and optimization of potent TcdB peptide inhibitors that inhibit TcdB glucosyltransferase by competing with toxin targets, Rho proteins.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Introduction

CDI background and current therapies

Toxins and domains of TcdA/TcdB

Biotechnology and Bioengineering ARTICLE Development of Peptide Glucosyltransferase Inhibitors With Comprehensive Coverage Across Clostridioides difficile Toxin B Sub‐Types Carly M. Catella1 | Sudeep Sarma1 | Caroline M. Hinesley2 | Corey E. Febo1 | Keith A. Breau3 | Deniz Durmusoglu1 | Ethan Purnell1 | Scott T. Magness2,3,4 | Carol K. Hall1 | Stefano Menegatti1,5 | Nathan Crook1 1Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina, USA | 2Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA | 3Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA | 4Department of Medicine, University of North Carolina at Chapel Hill, North Carolina, USA | 5Biomanufacturing Training and Education Center (BTEC), North Carolina State University, Raleigh, North Carolina, USA Correspondence: Nathan Crook ([nccrook@ncsu.edu](nccrook@ncsu.edu)) Received: 23 July 2025 | Revised: 7 October 2025 | Accepted: 25 October 2025 Funding: National Institutes of Health; North Carolina Biotechnology Center; Novo Nordisk Fonden; National Science Foundation. ABSTRACT Clostridioides difficile infection presents an escalating clinical challenge due to the proliferation of hypervirulent and antibiotic‐ resistant strains. The primary symptoms of disease, namely colitis and diarrhea, are induced by the release of two toxins: TcdA and TcdB. Targeting these toxins with peptide inhibitors provides an attractive therapeutic strategy that can be used alone or synergistically with standard antibiotic treatments to alleviate severe symptoms and reduce the risk of resistance development. In this study, we present the rational discovery and optimization of potent TcdB peptide inhibitors. The lead sequences effectively inhibit TcdB glucosyltransferase activity, the crucial enzymatic process leading to disease symptoms, by directly competing with the toxin's molecular targets, Rho proteins. Detailed enzymatic studies also elucidate distinct Michaelis constants, KM, for each substrate, UDP‐glucose and Rho‐proteins, for multiple TcdB GTD subtypes. The selected peptides demonstrated broad efficacy against the three most common TcdB subtypes, which are used in over 90% of clinical isolates. Additionally, the peptides delayed TcdB‐induced loss of barrier integrity and decreased apoptosis in a primary human colon epithelial monolayer model. This study highlights a novel therapeutic avenue with significant potential to enhance the treatment and management of C. difficile infections. 1 | Introduction Clostridioides difficile (C. difficile) is a gastrointestinal pathogen that is recognized as an urgent threat by the US Centers for Disease Control and Prevention (CDC) due to the prevalence of antibiotic resistant and hypervirulent strains causing significant morbidity, mortality, and healthcare burden (Centers for Disease Control and Prevention U.S. 2019; Rupnik et al. 2009; Schäffler and Breitrück 2018) . C. difficile Infection (CDI) is characterized by colitis, diarrhea, inflammation, and increased epithelial permeability, which are primarily driven by the release of clostridial glucosylating toxins (Carter et al. 2015; Alonso et al. 2022; Aktories et al. 2017) . Current treatment guidelines for CDI recommend discontinuing the antibiotic therapy mediating the gut dysbiosis and initiating targeted antibiotic therapy for C. difficile (e.g., vancomycin or fidaxomicin)(Johnson et al. 2021) . However, these treatments are not always effective and may lead to recurrent infections, antibiotic | Carly M. Catella and Sudeep Sarma contributed equally to this study. | | --- | | This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

FAQs

What causes the key symptoms of C. difficile infection in this study?

The study links colitis and diarrhea to the release of clostridial toxins TcdA and TcdB.

How do the peptide inhibitors work against TcdB?

They inhibit TcdB glucosyltransferase activity by directly competing with the toxin’s molecular targets, Rho proteins.

What evidence supports broad effectiveness across TcdB subtypes?

The selected peptides show broad efficacy against three major TcdB subtypes that account for over 90% of clinical isolates.

Sep 30, 2026

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