Development Of Peptide Inhibitors Targeting Clostridium Difficile Toxins A/b And Characterizing The Regulatory Role Of A Putative Negative Regulator Tcdc In Clostridium Difficile Toxin Gene Expression

<p>Clostridium difficile infections cause one of the most common and vital hospitalacquired</p> <p>diseases often associated with broad-spectrum antibiotic usage. TcdA and TcdB</p> <p>are the key virulence factors involved in major patho-physiology. While standard</p> <p>antibiotics provide some respite, due to the high relapse rates and the emergence of more</p> <p>severe disease presentations, antibiotics alone have often proven to be suboptimal.</p> <p>Therefore there is a desperate need to develop an effective non-antimicrobial</p> <p>therapeutics. Part of this work focuses on identification and further characterization of</p> <p>peptide therapeutic that target the major virulence factor TcdA/TcdB. Towards</p> <p>development of mechanistic-based anti-toxin agent, phage display was used to identify</p> <p>peptides that bind to the catalytic domain of C. difficile Toxin A. Characterization of the</p> <p>binding and inhibitory activity revealed that the lack of parent peptide ability to inhibit</p> <p>the cells in vivo. Further derivatization of above parent peptides in to irreversible binders</p> <p>lead to protects cells in vivo. Mass spectroscopy approaches revealed the peptide</p> <p>inhibition was mainly due to cross-linking of modified peptide in to key catalytic residues</p> <p>in active site. While there are still several steps required to further explore in terms of the</p> <p>stability of these compounds, agents like these could be potentially used prophylactically</p> <p>163</p> <p>to avoid extensive cellular damage during treatment with broad spectrum antibiotics or in</p> <p>populations prone to CDI.</p> <p>The other area, focused on this thesis, is identification of the functional role of a</p> <p>negative regulator (TcdC) involved in toxin gene expression. In this work, we used a</p> <p>variety of biochemical and genetic approaches and characterized TcdC is not repressor</p> <p>instead acts as an Extra Cytoplasmic Class (ECF) anti-sigma factor and was able to</p> <p>propose a new mechanistic model regarding the regulatory role of TcdC. As well as here</p> <p>we have successfully developed GFP-based reporter system which has a potential to be</p> <p>an adaptable tool for investigating fine details on toxin genes tuning. Being able to adopt</p> <p>in host environment is vital for survival and propagation of a pathogenic bacteria. Thus,</p> <p>exploring the regulatory nodes on PaLoc gene expression can be lead to exploit potential</p> <p>therapeutic opportunities hidden within such systems.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Open Access Dissertation

Discipline thesis:degree_discipline

Chemistry

Year dc:date.available

2013

Author dc:creator

• Abdeen, Sanofar Jainul

Contributors dc:contributor

• Andrew L. Feig

• Clostridium Difficile
• Negative regulator
• Peptide inhibitors
• ToxinC
• Toxins
• Biochemistry
• Chemistry

Repository record dc:identifier

https://digitalcommons.wayne.edu/oa_dissertations/627

OAI identifier oai:identifier

oai:digitalcommons.wayne.edu:oa_dissertations-1626