Biology subjects

McNulty, R.

Publications and source records attributed to McNulty, R..

5 recordsLinked to original sources

bioRxiv2025

Alpha hemolysin polymorphisms in methicillin-resistant Staphylococcus aureus clinical isolates regulate ADAM10-dependent neutrophil IL-1 beta secretion

Staphylococcus aureus -hemolysin (Hla) is a major virulence factor that utilizes cell surface ADAM10 to oligomerize and form a functional heptameric pore. We show here that Hla from strain USA300 is required to induce IL-1{beta} secretion by neutrophils and to cause severe corneal disease in mice. We also demonstrate that in contrast to USA300 and other clonal complex 8 (CC8) methicillin resistant S. aureus (MRSA) isolated from the skin, CC5 Hla from corneas of infected patients have single nucleotide polymorphisms (SNP) that result in two amino acid substitutions, D208E (Asp-Glu) and I275T (Ile-Thr). Structural modeling predicts CC5 Hla self-assembly and altered binding to ADAM10 that is distinct from CC8 Hla. The ADAM10 inhibitor GI254023X blocked neutrophil IL-1{beta} secretion induced by Hla-expressing CC8, but not by CC5 conditioned media, indicating that these Hla polymorphisms play an important role in Hla receptor binding and neutrophil IL-1{beta} secretion, and affect corneal disease severity.

microbiology↗

bioRxiv2025

RM1mAb avoids Intracellular degradation to Synergistically inhibit NLRP3 Inflammasome Activation in Familial Cold Autoinflammatory Syndrome

The NLRP3 inflammasome enables release of mitochondrial DNA to circulation. Circulating oxidized mitochondrial DNA generated in response to NLRP3 inflammasome activation functions as an alarmin that contributes to the maintenance of systemic inflammation. The discovery that NLRP3 could cleave oxidized mtDNA led to repurposed chemical inhibitors that dually target NLRP3 and DNA glycosylase OGG1, resulting in pro-survival type-1 interferon. Using molecular dynamics and immunology we show that RM1mAb, a full-length monoclonal antibody targeting the NLRP3 pyrin domain, can prevent NLRP3 from interacting with mitochondrial DNA. We further illustrate RM1mAb can exploit FC{gamma}Rs for cell entry and avoid destruction by the lysosomal pathway to inhibit IL-1{beta} secretion in peripheral mononuclear blood cells (PBMCs) isolated from patients with Familial Cold Autoinflammatory Syndrome harboring NLRP3 L353P gain of function mutation. We show RM1mAb and repurposed inhibitor TH5487 synergistically inhibit inflammasome activation. These findings illustrate the promise of exploiting FC{gamma}Rs as a means of IgG entry to target cytosolic proteins and improve human health. One-Sentence SummaryRM1mAb and TH5487 synergistically inhibit inflammasome activation in human FCAS PBMCs.

immunology↗

bioRxiv2025

TH5487 specifically targets NLRP3 in FCAS patients resistant to MCC950

The NLRP3 inflammasome plays a central role in innate immunity and is activated in response to mitochondrial dysfunction and oxidized DNA. Here, we demonstrate that repurposed small-molecule inhibitors originally developed for DNA glycosylases, TH5487 and SU0268, potently inhibit NLRP3 activation ex vivo in human Peripheral Blood Mononuclear Cells (PBMCs) with IC50 of 1.62 {micro}M and 3.24 {micro}M, respectively. We show that these inhibitors prevent mitochondrial localization of NLRP3 and directly block inflammasome assembly. They also reshape the immune landscape decreasing IL-1{beta}, while increasing IFN-{beta}. Structural and biophysical analyses reveal a two-site DNA binding model in which NLRP3 engages oxidized DNA with a KD1 of 0.268 nM and KD2 3.02 nM. Importantly, these inhibitors block IL-1{beta} secretion in L353P Familial Cold Autoinflammatory Syndrome (FCAS) patient PBMCs where MCC950 fails, demonstrating the therapeutic potential for inflammasome-driven diseases. Together, our findings reveal a novel druggable mechanism of inflammasome inhibition through interference with oxidized DNA sensing and localization, offering new opportunities for treatment of chronic inflammatory disorders.

immunology↗

bioRxiv2025

NLRP10 Cleaves Oxidized DNA inhibited by OGG1 inhibitors: A Newly Identified Role in DNA Damage Processing and Senescence Regulation.

Mitochondrial DNA (mtDNA) release into the cytosol is a critical event in innate immune activation, often acting as a damage-associated molecular pattern (DAMP) that triggers inflammasome assembly. Here, we demonstrate that NLRP3 plays a direct role in cleaving and facilitating the release of D-loop mtDNA into the cytosol. We further show that NLRP3 interacts with NLRP10. NLRP10-mediated ox-DNA cleavage involves a Schiff base intermediate and is inhibited by small molecules known to inhibit glycosylases. These findings support a model where NLRP10 interaction with oxidized DNA may contribute to long-term senescence secretory phenotype and modulate inflammasome activation. Our study highlights a novel mechanism by which NLRP10 can respond to mitochondrial stress signals to influence innate immunity and suggests therapeutic potential for targeting these interactions in inflammatory diseases.

immunology↗

bioRxiv2023

Small molecule inhibitor binds to NLRP3 and prevents inflammasome activation

Despite recent advances in the mechanism of oxidized DNA activating NLRP3, the molecular mechanism and consequence of oxidized DNA associating with NLRP3 remains unknown. Cytosolic NLRP3 binds oxidized DNA which has been released from the mitochondria, which subsequently triggers inflammasome activation. Human glycosylase (hOGG1) repairs oxidized DNA damage which inhibits inflammasome activation. The fold of NLRP3 pyrin domain contains amino acids and a protein fold similar to hOGG1. Amino acids that enable hOGG1 to bind and cleave oxidized DNA are conserved in NLRP3. We found NLRP3 could bind and cleave oxidized guanine within mitochondrial DNA. The binding of oxidized DNA to NLRP3 was prevented by small molecule drugs which also inhibit hOGG1. These same drugs also inhibited inflammasome activation. Elucidating this mechanism will enable design of drug memetics that treat inflammasome pathologies, illustrated herein by NLRP3 pyrin domain inhibitors which suppressed interleukin-1{beta} (IL-1{beta}) production in macrophages. One-Sentence SummaryNLRP3 cleaves oxidized DNA and small molecule drug binding inhibits inflammasome activation.

immunology↗