Discipline: Biological Sciences
Subcategory: Microbiology/Immunology/Virology
Session: 2
Room: Exhibit Hall A
Cassy M. Louis - Oakwood University
Co-Author(s): Morgan Narain, Oakwood University, AL; France Archange, Oakwood University, AL
Pathogenic microbes utilize strategies that enable them to evade host defenses, damage tissues and invade host cells. Cellular invasion is a well-orchestrated process in which bacterial proteins are tightly regulated and sorted to ensure proper invasion and survival post-invasion. Such process includes modulation of regulatory protein expression. There are gaps in understanding how microbial pathogens modulate certain regulatory proteins during invasion (or post-invasion) and how nanoparticles (NPs) can impede the cell invasion or survival post-invasion processes. The purpose of this study is to evaluate if NPs could reduce cell invasion strategies of HeLa cells caused by bacterial pathogens and to understand how NPs could regulate survival mechanisms post-cell invasion. Organisms used in this study include Streptococcus pyogenes, Staphylococcus aureus, and Methicillin-Resistant Staphylococcus aureus (MRSA). It is hypothesized that silver nanoparticles (AgNPs) can decrease cell invasion and alter the expression of regulatory and chaperones proteins during or post-cell invasion. To test the hypothesis, a cell invasion assay was performed using HeLa cell lines, protein expression levels were quantified using ELISA of Sortase A, (which displays virulent surface proteins needed for biofilm production and invasion), DnaK, (chaperone for highly structured protein folding), and HtrA Serine Protease A, (serine-activated proteases for protein regulation and protein folding especially under stressful environmental conditions). Data were analyzed by comparing NPs treated samples to untreated samples. Cell invasion assays show that AgNP reduces invasion of S. aureus by 79%. In NP-treated HeLa + S. pyogenes, the expression level of HtrA is downregulated by 12%, Dnak is upregulated by 40%, and Sortase A is downregulated by 20%. In NP-treated HeLa + S. aureus, HtrA is upregulated by 20%, DnaK is significantly increased by 900%, and sortase A is upregulated by 350%. In NP-treated Hela + MRSA, HtrA is upregulated by 50% and sortase A by 20%. In conclusion, AgNPs can alter the protein expression of HtrA, Sortase A and DNAk during or post-cell invasion. Future research involves measuring the expression of these regulatory proteins at the gene expression level in infected HeLa cells treated with NPs compared to non-treated infected HeLa cells. The findings of this study could be used to decrease complications associated with various pathogenic organisms. References: Singh V, Phukan UJ. 2019. Interaction of host and Staphylococcus aureus protease-system regulates virulence and pathogenicity. Med Microbiol Immunol. Oct;208(5):585-607. doi: 10.1007/s00430-018-0573-y; Willey, J. M., Sherwood, L., & Woolverton, C. J. (2017). Prescott’s microbiology. New York, NY: McGraw-Hill.
Funder Acknowledgement(s): NSF/HBCU-UP UNCF McBay
Faculty Advisor: Elaine Vanterpool, evanterpool@oakwood.edu
Role: I measured the protein expression levels of sortase A, HtrA and DNAk in NPs-treated Hela + S. aureus, S. pyrogenes and MRSA vs. untreated HeLa + S. aureus, S. pyrogenes and MRSA using ELISA and I analyzed the data.