Biology subjects

Kulkarni, V.

Publications and source records attributed to Kulkarni, V..

17 recordsLinked to original sources

bioRxiv2026

Maftivimab monotherapy is effective in a non-human primate model of Bundibugyo virus disease

The 2026 outbreak of Bundibugyo ebolavirus (BDBV) in the Democratic Republic of the Congo and Uganda has created an urgent need for treatments for BDBV disease, yet the only FDA-approved ebolavirus therapeutics, the monoclonal antibody (mAb) cocktail Inmazeb and the mAb Ebanga, are indicated for Zaire ebolavirus (EBOV). Maftivimab (REGN3479), the most potent neutralizing component of Inmazeb, targets ebolavirus species GPs broadly; however, how it engages BDBV GP, whether it neutralizes BDBV-2026, and whether it protects against BDBV disease in vivo are unknown. Here we show that Maftivimab binds to BDBV-2007 GP with high affinity and potently neutralizes pseudoviruses carrying GP from a 2007 reference strain and the 2026 outbreak lineage. Additionally, a cryo-electron microscopy structure of Maftivimab Fab bound to trimeric BDBV-2007 GP superimposes closely on the EBOV GP:Maftivimab complex; importantly, all GP contact residues are conserved between the 2007 and 2026 BDBV sequences. Finally, in cynomolgus macaques challenged with BDBV-2007, a single dose of Maftivimab monotherapy given 7 days after infection, after the onset of clinical disease, rescued 6 of 6 animals, whereas 5 of 6 placebo-treated animals succumbed. These findings demonstrate that Maftivimab neutralizes BDBV, binds to its epitope on BDBV GP and is efficacious in treating established BDBV disease in the macaque model. The data support its evaluation in clinical trials during the ongoing or future outbreak.

immunology↗

bioRxiv2026

Host ecological context influences taxonomic diversity and functional conservation of gut microbiome across anthropogenic habitats in macaques

Gut microbiome responses to anthropogenic disturbance vary across wildlife species, even within similarly disturbed landscapes. What drives this variation is unclear: whether it reflects anthropogenic exposure itself or broader ecological differences among hosts. We tested this using three macaque species with contrasting ecology, Bonnet, Rhesus, and Lion-tailed macaques, sampled across 12 sites in southern India spanning contrasting anthropogenic exposure, using 16S rRNA gene sequencing (n = 127) and shotgun metagenomics on a subset of samples. The two synurbanized species exhibited a similar magnitude of microbiome restructuring but differed in the taxa underlying these changes; no differentially abundant amplicon sequence variants were shared across all three species, indicating that shared anthropogenic exposure did not produce uniform microbial responses across hosts. The specialist Lion-tailed macaque showed a more extensive response, characterized by reduced diversity and phylogenetically structured compositional change. The Bonnet macaque showed greater microbial similarity with the Rhesus macaque than with the Lion-tailed macaque during sympatric co-occurrence. Despite taxonomic divergence, functional pathway architecture was broadly conserved across species and habitats, with selective shifts in pathways including vitamin B6 biosynthesis and fermentation. Together, these findings show that microbiome responses to anthropogenic environments are jointly shaped by ecological context and host ecology, with host differences in diet, habitat use, and ecological history influencing the magnitude and nature of microbial restructuring. These findings show that taxonomic diversity and functional potential respond as partially decoupled axes under anthropogenic pressure, with implications for assessing microbiome resilience across ecologically heterogeneous wildlife.

ecology↗

bioRxiv2026

Phosphorylated ubiquitin is a secondary messenger and an epigenetic mark mediating mitochondria to nucleus signaling

AbstractParkinsons disease (PD) is commonly associated with dysfunctional mitochondrial homeostasis. PINK1, a S/T kinase mutated in early-onset PD, generates phosphoserine 65 ubiquitin (pS65Ub) on damaged mitochondria facilitating their removal. Here, we show that pS65Ub translocates into the nucleus after generation at damaged mitochondria and is directly attached to substrates by resident E3 ligases. Histone H2A is a major substrate and is modified at lysine 119 (H2AK119) by the polycomb silencer, E3 ligase RING1B. At nucleosomes, pS65Ub simultaneously suppresses RING1B and potentiates H2A deubiquitinases USP16 and USP21. Epigenetic profiling and RNA sequencing reveal that pS65Ub is enriched at the promoters of poorly expressed yet dynamically regulated genes and is associated with H2AK119ub depletion. Functionally, we show that pS65Ub enrichment drives polycomb target gene expression, which accelerates the maturation of dopaminergic neurons. Importantly, post-mortem PD brains exhibit elevated nuclear pS65Ub, potentially linking nuclear pS65Ub accumulation with disease pathogenesis. Together, these data indicate that pS65Ub generated at damaged mitochondria regulates fundamental cellular processes at distant sites.

cell biology↗

bioRxiv2025

Polar ecosystems harbor highly divergent DNA viruses underrepresented in current reference databases

Viruses are the most abundant biological entities on Earth, yet most of their diversity remains unsampled and unevenly represented across ecosystems. To test whether viral novelty is structured more by biome or latitude, we analyzed 120 curated environmental DNA metagenomes spanning marine and terrestrial habitats across equatorial temperate, Arctic, and Antarctic regions. Using a unified metagenomic and phylogenomic workflow, we reconstructed viral protein families, linked environmental sequences to the IMGVR v4.1 reference collection, and quantified divergence using three complementary measures: within-clade patristic distance, the bridging edge to the nearest reference neighbor, and phylogenetic tree-shape statistics. Because distances within phylogenetic trees are not independent, all inference was performed at the sample level. Across all samples, reconstructed environmental viral sequences were substantially more divergent from current reference genomes than their database homologs. The dominant pattern was biome-driven: terrestrial viromes were consistently farther from IMGVR references than marine viromes in every latitudinal band, and this contrast was supported by both branch-length and topology-based metrics. Latitude modulated this baseline signal, with polar ecosystems, especially Antarctic terrestrial samples, occupying the most divergent end of the two-axis landscape. Tree imbalance statistics showed that terrestrial viral phylogenies were more deeply branching and more asymmetric than marine ones, providing independent support for the biome effect. In contrast, some previously reported polar contrasts weakened after correcting for pseudoreplication and using proper sample-level replication. These results argue that viral novelty is structured primarily by biome, with polar environments amplifying an already strong terrestrial-marine contrast. The findings also indicate that current reference databases remain disproportionately sparse for terrestrial, especially polar terrestrial, viromes. Expanding viral sampling in these environments will be essential for improving ecological inference, improving database coverage, and refining our understanding of global viral diversity.

evolutionary biology↗

bioRxiv2025

Ridge-assisted Micro Positioning of Cells and Particles in a Microchannel

The capability to deterministically and precisely control the lateral position of focused cell streams in a microchannel provides diverse opportunities for biomedical applications, including cell concentration, imaging flow cytometry, and cell-based liquid biopsy platforms. Inertial microfluidics introduced various high-throughput strategies for ordering particles and cells within microchannels. However, existing approaches do not permit precise control over the lateral focusing position of cells. By leveraging engineered microvortices generated by channel ridges and fluidic lift forces, we present a microfluidic method for deterministically positioning focused cell streams to desired lateral streamlines. Unlike inertial focusing, the ridge-assisted micro positioning (RAMP) is independent of particle size and flow rate, enabling polydisperse particles (10 to 30 m) to be focused to the same streamline across a broad range of flow rates (250-1000 L/min). The focusing position can be precisely adjusted by altering ridge placement and geometry, achieving both small (5 m) and large ([≥]15 m) lateral shifts in a controlled manner. Applying the RAMP concept, we developed clog-free microfluidic cell concentrators that can enrich single cells and clusters of cells to desired concentration factors and demonstrate the ability to focus particles in undiluted whole blood. Together, these results establish RAMP as a versatile platform for precise cell positioning in complex biological fluids. TeaserUse of designer vortices produced by ridges allows cells to be focused in user-defined streamlines across a microchannel over a wide range of flow rates.

bioengineering↗

bioRxiv2025

Single dose alum adjuvanted RBD protein vaccine provides protection against homologous challenge with SARS-CoV-2 Washington strain and heterologous rechallenge with Delta and Omicron BA.5 variants in K18 hACE2 mouse model

Most COVID-19 vaccination strategies require at least two doses-a primary vaccine followed by a booster dose with the updated variant-specific vaccine. However, vaccine and booster dose hesitancy make it challenging to administer multiple doses of vaccines in the unvaccinated and vaccinated populations, respectively. Thus, it is important to determine if vaccinated individuals exposed to SARS-CoV-2 infection develop immune responses that may protect them against emerging variants of concern (VoCs). We have developed mouse models to understand the protective efficacy of an RBD-based vaccine against challenge and rechallenge with SARS-CoV-2 VoCs. Mice were vaccinated with RBD protein vaccine formulated in 2% Alhydrogel (alum) adjuvant by subcutaneous route. To determine the efficacy of RBD vaccine, mice were challenged approximately 4 weeks post-vaccination with SARS-CoV-2 variants by intranasal route. To determine the efficacy of RBD vaccine against SARS-CoV-2 rechallenge, mice were rechallenged with SARS-CoV-2 Delta and Omicron BA.5 variants at day 14 post SARS-CoV-2 Washington (WA) strain challenge. Our data suggest that single dose alum adjuvanted RBD protein from Wuhan strain provides protection against homologous challenge with SARS-CoV-2 WA strain but failed to provide protection against heterologous challenge with Delta and Omicron BA.5 variants. Interestingly, vaccinated mice that survived homologous challenge with the WA strain showed protection against heterologous rechallenge with Delta and omicron BA.5 variants. Furthermore, infectious viral loads of Delta and Omicron BA.5 were not detected in the lung tissues collected from the rechallenged mice at 3 days post-rechallenge. The data suggest that a single dose RBD vaccine from the ancestral Wuhan strain together with survival from WA strain challenge induces protective immune responses against Delta and Omicron BA.5 variants rechallenge. These mouse models will be useful to determine the immune responses that correlate with protection against challenge and rechallenge with SARS-CoV-2 VoCs.

microbiology↗

bioRxiv2024

Directional Immobilisation of SpyTag Bacteriophage on PDMS surfaces for Phage based Microfluidics

The increasing incidence of bacterial infections caused by antibiotic-resistant pathogens worldwide underlines the need to develop novel diagnostic tools enabling the early initiation of targeted antimicrobial therapy. One promising possibility is to unite the high specificity and sensitivity of phage-based applications with the speed and sensitivity provided by microfluidic devices. As a prerequisite of developing such systems, we aimed at the directional immobilization of phages on the surface of Polydimethylsiloxane (PDMS), a material commonly used for building such devices. Our work utilised the covalent interaction between two proteins: SpyTag, genetically encoded on the capsid of the phage, and BslA-SpyCatcher fusion protein, purified and surface displayed on PDMS. We demonstrate a simple methodology for the directional tail up immobilisation of SpyTagged Phage on to user defined locations on the surface of a PDMS device and subsequent on chip capture and infection of a cognate host. Our technique serves to illustrate a generally applicable solution to develop the next generation of phage based bio-sensors.

bioengineering↗

bioRxiv2024

Immunotherapy with nebulized pattern recognition receptor agonists restores severe immune paralysis and improves outcomes in mice with influenza-associated pulmonary aspergillosis

Influenza-associated pulmonary aspergillosis (IAPA) is a potentially deadly super-infection in patients with influenza pneumonia, especially those with severe disease, underlying immunosuppression, corticosteroid therapy, or requiring intensive care support. Given the high mortality of IAPA, adjunct immunomodulatory strategies remain a critical unmet need. Previously, desensitization of pattern recognition pathways has been described as a hallmark of IAPA pathogenesis and predictor of mortality in IAPA patients. Therefore, we studied the impact of nebulized Toll-like receptor 2/6/9 agonists Pam2 CSK4 (Pam2) and CpG oligodeoxynucleotides (ODN) on infection outcomes and pulmonary immunopathology in a corticosteroid-immunosuppressed murine IAPA model. Mice with IAPA receiving mock therapy showed rapidly progressing disease and a paralyzed immune response to secondary A. fumigatus infection. Nebulized Pam2ODN was well tolerated and significantly prolonged event-free survival. Specifically, dual-dose Pam2ODN therapy before and after A. fumigatus infection led to 81% survival and full recovery of all survivors. Additionally, transcriptional analysis of lung tissue homogenates revealed induction of PRR signaling and several key effector cytokine pathways after Pam2ODN therapy. Moreover, transcriptional and flow cytometric analyses suggested enhanced recruitment of macrophages, natural killer cells, and T cells in Pam2ODN-treated mice. Collectively, immunomodulatory treatment with nebulized Pam2ODN strongly improved morbidity and mortality outcomes and alleviated paralyzed antifungal immunity in an otherwise lethal IAPA model. These findings suggest that Pam2ODN might be a promising candidate for locally delivered immunomodulatory therapy to improve outcomes of virus-associated mold infections such as IAPA.

immunology↗

bioRxiv2024

TXTL-Powered K1F Internal Capsid Protein Engineering for Specific, Orthogonal and Rapid Phage-based Pathogen Detection

The internal capsid proteins that reside within phage of the Podoviridae family hold high potential for being used as sensitive and reliable diagnostic tools. The concealed nature of the capsid interior ensures that any encapsulated signal or signal generating enzyme, e.g., fused to an internal capsid protein, is suppressed whilst the phage is unaccompanied by its host. Furthermore, the only naturally occurring mechanism for releasing the internal capsid proteins, and therefore exposing their amalgamated signal/enzyme, is for them to be passed through the tail and subsequently ejected out of the phage, a post-adsorption phenomenon which occurs when the host is present, thus presenting a precise model for signal/enzyme release only upon pathogen presence. Here, a small N terminal subunit of the NanoLuc luciferase is fused and incorporated into the K1F internal capsid structure using a simple, non-genomic method. This internalised subunit is exposed to the test solution containing its C terminal counterpart (natural complementation immediately forms the full NanoLuc enzyme) and substrate furimazine in an inducible manner which mimics the presence of the K1F host, E. coli K1 thereby presenting a novel method for rapidly detecting this disease causing pathogen. Finally, it is expected that by building upon this internal capsid protein engineering approach, which completely bypasses the time-inducing processes of intracellular nucleic acid transcription and translation, an unprecedentedly rapid detection device can be developed for an array of bacterial pathogens.

synthetic biology↗

bioRxiv2023

Dynamic Changes in Macrophage Polarization during the Resolution Phase of Periodontal Disease

Periodontal inflammation is largely governed by infiltration of myeloid cells, in particular macrophages. Polarization of M{varphi} within the gingival tissues is a well-controlled axis and has considerable consequences for how M{varphi} participate in inflammatory and resolution (tissue repair) phases. We hypothesize that periodontal therapy may instigate a pro-resolution environment favoring M2 M{varphi} polarization and contribute towards resolution of inflammation post-therapy. We aimed to evaluate the markers of macrophage polarization before and after periodontal therapy. Gingival biopsies were excised from human subjects with generalized severe periodontitis, undergoing routine non-surgical therapy. A second set of biopsies were excised after 4-6 weeks to assess the impact of therapeutic resolution at the molecular level. As controls, gingival biopsies were excised from periodontally healthy subjects, undergoing crown lengthening. Total RNA was isolated from gingival biopsies to evaluate pro- and anti-inflammatory markers associated with macrophage polarization by RT-qPCR. Mean periodontal probing depths, CAL and BOP reduced significantly after therapy and corroborated with the reduced levels of periopathic bacterial transcripts after therapy. Compared to heathy and treated biopsies, higher load of Aa and Pg transcripts were observed in disease. Lower expression of M1M{varphi} markers (TNF-, STAT1) were observed after therapy as compared to diseased samples. Conversely, M2M{varphi} markers (STAT6, IL-10) were highly expressed in post-therapy as opposed to pre-therapy, which correlated with clinical improvement. These findings corroborated with murine ligature-induced periodontitis and resolution model, comparing the respective murine M{varphi} polarization markers (M1 M{varphi}: cox2, iNOS2 and M2 M{varphi}: tgm2 and arg1). Our findings suggest that imbalance in M1 and M2 polarized macrophages by assessment of their markers can provide relevant clinical information on the successful response of periodontal therapy and can be used to target non-responders with exaggerated immune responses.

immunology↗

bioRxiv2022

Comparative immune responses to Mycobacterium tuberculosis in people with latent infection or sterilizing protection

Tuberculosis (TB) affects 2 billion people worldwide and causes 1.5 million deaths every year. There is great need for new TB vaccines that are more efficacious than the currently licensed BCG vaccine, which provides only limited protection. Our goal was to identify potential targets for new TB vaccines by characterizing the immune responses that distinguish individuals with sterilizing protection against TB (TB-resisters), defined by presence of TB-specific immune responses and absence of latent infection, from individuals with latent TB infection (LTBI-participants). Cryopreserved peripheral blood mononuclear cells (PBMC) from 13 TB-resisters and 10 LTBI-participants were analyzed by high dimensional spectral flow cytometry after overnight M. tuberculosis (Mtb) antigenic stimulation or unstimulated control. Activation of conventional and nonconventional T cells, NK cells, and antigen presenting cells (APC) was compared between the two groups. Compared with LTBI-participants, TB-resisters had significantly higher proportions of conventional and nonconventional T cells expressing granzyme B (GranzB) and PD-1, and of polyfunctional cells in unstimulated and Mtb-stimulated conditions. Conversely LTBI-participants had higher expression of CD25, CD69, CD107a, IL10 and IFN{gamma}. An unbiased cluster analysis revealed higher frequency of recently described CD8+GMM+GranzB+ T cells in unstimulated PBMC from TB-resisters than LTBI-participants. APC activation revealed very few differences between TB-resisters and LTBI-participants. An exploratory analysis of responses in 14 BCG-recipients with minimal exposure to TB showed multiple differences with TB-resisters and LTBI-participants in PBMC activation; lower polyfunctionality of T cells and APC in Mtb-stimulated PBMC; and absence of CD8+GMM+GranzB+ T cells. We conclude that combined increased T cell expression of GranzB and checkpoint inhibitors may contribute to immune protection against TB and may be targeted by new vaccines.

immunology↗

bioRxiv2021

Localization of infection in neonatal rhesus macaques after oral viral challenge

While vertical transmission of human immunodeficiency virus (HIV) can occur in utero and during delivery and through breastfeeding. We utilized Positron Emission Tomography (PET) imaging coupled with fluorescent microscopy of 64Cu-labeled photoactivatable-GFP-HIV (PA-GFP-BaL) to determine how HIV virions distribute and localize in neonatal rhesus macaques two and four hours after oral viral challenge. Our results show that by four hours after oral viral exposure, HIV virions localize to and penetrate the rectal mucosa. We also used a dual viral challenge with a non-replicative viral vector and a replication competent SHIV-1157ipd3N4 to examine viral transduction and dissemination at 96 hours. Our data show that while SHIV-1157ipd3N4 infection can be found in the oral cavity and upper gastrointestinal (GI) tract, the small and large intestine contained the largest number of infected cells. Moreover, we found that T cells were the biggest population of infected immune cells. Thus, thanks to these novel technologies, we are able to visualize and delineate of viral distribution and infection throughout the entire neonatal GI tract during acute viral infection. Author SummaryApproximately 1.8 million children are currently living with human immunodeficiency virus (HIV). While mother-to-child HIV transmission can occur in utero and during delivery, it most commonly occurs through breastfeeding, creating the need to understand how the virus moves throughout the body and infects the infant once breast milk is consumed. Here, we used multiple imaging techniques and PCR to determine how HIV distributes throughout the gastrointestinal tract after oral viral exposure and in which tissues and cell types become acutely infected. We found that HIV rapidly spreads throughout and penetrates the entire gastrointestinal tract as early as four hours after exposure. We also found that the intestine contained the largest number of infected cells at 96 hours and that most cells infected were T cells. Our study shows that these imaging technologies allow for the examination of viral distribution and infection in a rhesus macaque model.

cell biology↗

bioRxiv2021

Efficient inhibition of HIV using CRISPR/Cas13d nuclease system

Recently discovered Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas13 proteins are programmable RNA-guided ribonucleases that target single-stranded RNA (ssRNA). CRISPR/Cas13 mediated RNA targeting has emerged as a powerful tool for detecting and eliminating RNA viruses. Here, we demonstrate the effectiveness of CRISPR/Cas13d to inhibit HIV-1 replication. We designed guide RNAs (gRNAs) targeting highly conserved regions of HIV-1. RfxCas13d (CasRx) in combination with HIV-specific gRNAs efficiently inhibited HIV-1 replication in cell line models. Furthermore, simultaneous targeting of four distinct sites in the HIV-1 transcript resulted in robust inhibition of HIV-1 replication. We also show the effective HIV-1 inhibition in primary CD4+ T-cells and suppression of HIV-1 reactivated from latently infected cells using the CRISPR/Cas13d system. Our study demonstrates the utility of the CRISPR/Cas13d nuclease system to target acute and latent HIV infection and provides an alternative treatment modality against HIV.

molecular biology↗

bioRxiv2021

Rapid and Efficient Inactivation of SARS-CoV-2 from Surfaces using UVC Light Emitting Diode Device

Efforts are underway to develop countermeasures to prevent the environmental spread of COVID-19 pandemic caused by SARS-CoV-2. Physical decontamination methods like Ultraviolet radiation has shown to be promising. Here, we describe a novel device emitting ultraviolet C radiation (UVC), called NuvaWave, to rapidly and efficiently inactivate SARS-CoV-2. SARS-CoV-2 was dried on a chambered glass slides and introduced in a NuvaWave robotic testing unit. The robot simulated waving NuvaWave over the virus at a pre-determined UVC radiation dose of 1, 2, 4 and 8 seconds. Post-UVC exposure, virus was recovered and titered by plaque assay in Vero E6 cells. We observed that relative control (no UVC exposure), exposure of the virus to UVC for one or two seconds resulted in a >2.9 and 3.8 log10 reduction in viral titers, respectively. Exposure of the virus to UVC for four or eight seconds resulted in a reduction of greater than 4.7-log10 reduction in viral titers. The NuvaWave device inactivates SARS-CoV-2 on surfaces to below the limit of detection within one to four seconds of UVC irradiation. This device can be deployed to rapidly disinfect surfaces from SARS-CoV-2, and to assist in mitigating its spread in a variety of settings.

microbiology↗

bioRxiv2019

The Five-Primer Challenge: An inquiry-based laboratory module for synthetic biology

New technologies in DNA synthesis and assembly give genetic engineers complete freedom in genetic design, where virtually any plasmid DNA sequence can be created efficiently and economically. Learning how to design, construct, and test new DNA sequences is a critical skill for researchers in molecular biology and biotechnology. Here we present a student-centered, inquiry-based module in which students learn how to control bacterial gene expression by appplying various DNA assembly techniques. The central activity in this learning module is termed the Five-Primer Challenge. Each student is allowed to order up to five 60-mer oligonucleotide primers to then modify a GFP expression plasmid with the goal of increasing GFP expression as much as possible. This module was developed and implemented at the 2016 Cold Spring Harbor Laboratory Synthetic Biology Course, and was effective at engaging students in critical thinking and in promoting student learning.

scientific communication and education↗

bioRxiv2019

Interactions with presynaptic photoreceptors mediated by the Dpr11 and DIP-γ cell surface proteins control selection and survival of Drosophila amacrine neurons

Drosophila R7 UV photoreceptors (PRs) are divided into yellow (y) and pale (p) subtypes with different wavelength sensitivities. yR7 PRs express the Dpr11 cell surface protein and are presynaptic to Dm8 amacrine neurons (yDm8) that express Dpr11s binding partner DIP-{gamma}, while pR7 PRs synapse onto DIP-{gamma}-negative pDm8 neurons. Dpr11 and DIP-{gamma} expression patterns define yellow and pale medulla color vision circuits that project to higher-order areas. DIP- {gamma} and dpr11 mutations affect the morphology of yDm8 arbors in the yellow circuit. yDm8 neurons are generated in excess during development and compete for presynaptic yR7 partners. Transsynaptic interactions between Dpr11 and DIP-{gamma} are required for generation of neurotrophic signals that allow yDm8 neurons to survive. yDm8 and pDm8 neurons do not normally compete for neurotrophic support, but can be forced to do so by manipulating R7 subtype fates. DIP-{gamma}-Dpr11 interactions allow yDm8 neurons to select yR7 PRs as their home column partners.

neuroscience↗

bioRxiv2018

Inducible Lung Epithelial Resistance Requires Multisource Reactive Oxygen Species Generation to Protect against Bacterial Infections

Pneumonia remains a global health threat, in part due to expanding categories of susceptible individuals and increasing prevalence of antibiotic resistant pathogens. However, therapeutic stimulation of the lungs mucosal defenses by inhaled exposure to a synergistic combination of Toll-like receptor (TLR) agonists known as Pam2-ODN promotes mouse survival of pneumonia caused by a wide array of pathogens. This inducible resistance to pneumonia relies on intact lung epithelial TLR signaling, and inducible protection against viral pathogens has recently been shown to require increased production of epithelial reactive oxygen species (ROS) from multiple epithelial ROS generators. To determine whether similar mechanisms contribute to inducible antibacterial responses, the current work investigates the role of ROS in therapeutically-stimulated protection against Pseudomonas aerugnosa challenges. Inhaled Pam2-ODN treatment one day before infection prevented hemorrhagic lung cytotoxicity and mouse death in a manner that correlated with reduction in bacterial burden. The bacterial killing effect of Pam2-ODN was recapitulated in isolated mouse and human lung epithelial cells, and the protection correlated with inducible epithelial generation of ROS. Scavenging or targeted blockade of ROS production from either dual oxidase or mitochondrial sources resulted in near complete loss of Pam2-ODN-induced bacterial killing, whereas deficiency of induced antimicrobial peptides had little effect. These findings support a central role for multisource epithelial ROS in inducible resistance against bacterial pathogens and provide mechanistic insights into means to protect vulnerable patients against lethal infections.

immunology↗