Biology subjects

Cirillo, J. D.

Publications and source records attributed to Cirillo, J. D..

4 recordsLinked to original sources

bioRxiv2024

Microbicidal Mechanisms for Light-Activated Molecular Nanomachines in Mycobacterium smegmatis: A Model for Pathogenic Bacteria

There is a global health crisis of antimicrobial resistance, with over a million deaths annually attributed to antimicrobial-resistant pathogens, and mycobacterial infections are a major cause of antimicrobial-resistant infections, leading to more deaths than any other single infectious agent. Notably, the rise of multidrug-resistant (MDR), extensively drug-resistant (XDR), and totally drug-resistant (TDR) strains of Mycobacterium tuberculosis led to higher mortality rates and challenge all existing antibiotic regimens. Light-activated molecular nanomachines (MNMs) represent a promising class of broad-spectrum antimicrobial agents that could help counter this rise in antimicrobial resistance. Addressing a key knowledge gap, this study explores the mechanisms of action for MNMs in Mycobacterium smegmatis, a surrogate model for pathogenic mycobacteria. We show that fast rotor MNMs kill up to 97% of M. smegmatis and co-localize with the bacteria as part of their mechanism of action. The ability to translate these observations to pathogenic mycobacteria was demonstrated by the ability of MNMs to kill 93.5% of M. tuberculosis under similar conditions. These findings suggest that MNMs may provide innovative sustainable antimicrobial agents for the treatment of drug-resistant mycobacterial infections. Graphical AbstractBacteria exposed to MNMs have two distinct outcomes when activated by 365 nm light. Slow motors (MNM 2 and 4) have no rotational action, remains outside the bacteria and have little to no effect on bacterial viability. Whereas fast motors (MNM 1 and 3) co-localize and embed into the bacterial cell wall causing disruptions that lead to a significant reduction in bacterial viability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/616754v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@70991corg.highwire.dtl.DTLVardef@541a36org.highwire.dtl.DTLVardef@18504bcorg.highwire.dtl.DTLVardef@1fa08c3_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2023

Peptide-mimetic treatment of Pseudomonas aeruginosa in a mouse model of respiratory infection

The rise of drug resistance has become a global crisis, with >1 million deaths due to resistant bacterial infections each year. Pseudomonas aeruginosa, in particular, remains a serious problem with limited solutions due to complex resistance mechanisms that now lead to more than 32,000 multidrug-resistant (MDR) infections and over 2,000 deaths annually. While the emergence of resistant bacteria has become concerningly common, identification of useful new drug classes has been limited over the past 40+ years. We found that a potential novel therapeutic, the peptide-mimetic TM5, is effective at killing P. aeruginosa and displays sufficiently low toxicity for mammalian cells to allow for use in treatment of infections. Interestingly, TM5 kills P. aeruginosa more rapidly than traditional antibiotics, within 30-60 minutes in vitro, and is effective against a range of clinical isolates. In vivo, TM5 significantly reduced bacterial load in the lungs within 24 hours compared to untreated mice and demonstrated few adverse effects. Taken together, these observations suggest that TM5 shows promise as an alternative therapy for MDR P. aeruginosa respiratory infections.

microbiology↗

bioRxiv2021

Relative Mutant N501Y SARS-CoV-2 Spike Protein RBD Inhibition of Anti-Spike Protein IgG and ACE-2 Binding to Spike Protein Species

In the SARS-CoV-2 coronavirus pandemic of 2019 (COVID-19), it has become evident that the ACE-2 receptor-binding domain (RBD) of the viral spike protein (SP) is the target of neutralizing antibodies that comprise a critical element of protective immunity to the virus. The most definitive confirmation of this contention is that the two mRNA COVID-19 vaccines in general use, which elicit antibodies specific for the RBD, exhibit approximately 95% protective efficacy against COVID-19. A potential challenge to vaccine efficacy is the emergence of SARS-CoV-2 variants possessing multiple mutations affecting amino acid residues in the RBD. Of concern are variants that arose in the United Kingdom, Brazil and South Africa. One of the variants, designated B.1.351, has shown a higher transmissibility due to greater affinity for the ACE-2 receptor and decreased neutralization by convalescent plasma, therapeutic monoclonal antibodies, and post-vaccination plasma. Common to several of the variants is the N501Y mutation in the RBD, which may be responsible for at least part of the observed variant properties. To test this hypothesis, we measured the ability of the Y501 RBD to inhibit binding of the wild type RBD and full SP (S1 + S2) to the ACE-2 protein and a human monoclonal IgG antibody elicited to the wild type RBD, relative to the wild type RBD in two enzyme-linked immunosorbent assays (ELISAs). We found no significant difference in the IC50 of the two RBD species inhibition of ACE-2 binding, but unexpectedly found that the IC50 of the wild type RBD inhibition of antibody binding was nearly twice that of the Y501 RBD, reflecting a lower affinity. These results suggest that the individual N501Y mutation does not contribute to altered viral properties by itself, but may contribute to a collective conformational shift produced by multiple mutations.

biochemistry↗

bioRxiv2019

Persistent DNA Hyper-methylation Dampens Host Anti-Mycobacterial Immunity

Mycobacterium tuberculosis (Mtb) has co-evolved with humans for millennia and developed multiple mechanisms to evade host immunity. Restoring host immunity in order to shorten existing therapy and improve outcomes will require identifying the full complement by which host immunity is inhibited. Perturbing host DNA methylation is a mechanism induced by chronic infections such as HIV, HPV, LCMV and schistosomiasis to evade host immunity. Here, we evaluated the DNA methylation status of TB patients and their asymptomatic household contacts demonstrating that TB patients have DNA hyper-methylation of the IL-2-STAT5, TNF-NF-{varkappa}B and IFN-{gamma} signaling pathways. By MSRE-qPCR, multiple genes of the IL-12-IFN-{gamma} signaling pathway (IL12B, IL12RB2, TYK2, IFNGR1, JAK1 and JAK2) were hyper-methylated in TB patients. The DNA hyper-methylation of these pathways is associated with decreased immune responsiveness with decreased mitogen induced upregulation of IFN-{gamma}, TNF, IL-6 and IL-1{beta} production. The DNA hyper-methylation of the IL-12-IFN-{gamma} pathway was associated with decreased IFN-{gamma} induced gene expression and decreased IL-12 inducible up-regulation of IFN-{gamma}. This work demonstrates that immune cells from TB patients are characterized by DNA hyper-methylation of genes critical to mycobacterial immunity resulting in decreased mycobacteria-specific and non-specific immune responsiveness.

immunology↗