A translational precision-cut lung slice model for host-response and therapeutic testing in pneumocystis pneumonia

The National Institute of Allergy and Infectious Diseases awarded Mayo Clinic $242,100 on September 1, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to develop and validate a translational precision-cut lung slice (PCLS) model for testing host-response mechanisms and therapeutic agents in Pneumocystis pneumonia.

The project, titled "A Translational Precision-Cut Lung Slice Model for Host-Response and Therapeutic Testing in Pneumocystis Pneumonia," addresses drug development barriers created by Pneumocystis jirovecii's inability to be continuously cultured in vitro. The recipient has developed a novel ex vivo infection-preserving PCLS model derived from immunosuppressed mice with fulminant pneumocystis pneumonia that retains the infected lung microenvironment. This system enables concurrent quantification of host immune responses and testing of anti-Pneumocystis agents while using substantially less test material than whole-animal models. Preliminary data demonstrate that PCLS maintain viability and show reproducible reduction in fungal burden following treatment with pentamidine and the novel antifungal agent ISFP10, while also exhibiting suppression of inflammatory cytokine responses.

The work spans two primary aims: standardizing and validating an infection-preserving PCLS system for anti-Pneumocystis screening using benchmark agents and novel compounds, and integrating multiplexed host-response assays. The performance period runs from September 1, 2026, through August 31, 2028, with work performed in Rochester, Minnesota. This is a Project Grant award under the assistance type classification.

Abstract

Pneumocystis jirovecii pneumonia (PJP) remains a major cause of morbidity and mortality in HIV/AIDS1-4. The world health organization has classified pneumocystis jirovecii among its "fungal priority pathogens," emphasizing the urgent need for novel THERAPIES5. Drug development has been hindered by the organism's inability to be continuously cultured in vitro, limiting mechanistic studies and systematic drug screening. We have developed a novel EX vivo infection-preserving precision-cut lung slice (pcls) model derived from immunosuppressed mice with fulminate pneumocystis pneumonia (PCP). This system retains the infected lung microenvironment, allowing for concurrent quantification of host immune responses and testing of anti-pneumocystis agents, using far less test agents than in whole animals. Preliminary data demonstrate pcls maintain viability, and demonstrate reproducible reduction in fungal burden after treatment with pentamidine or the novel anti-fungal agent ISFP106-9, while also exhibiting suppression of inflammatory cytokine RESPONSES10-12. We hypothesize this EX vivo infection-preserving pcls platform will provide standardized and physiologically relevant screening for both anti-pneumocystis and anti-inflammatory agents during pneumocystis infection. Aim 1: standardize and validate an infection-preserving PCP pcls system for anti-pneumocystis screening. We will optimize our pcls model to yield reproducible, quantitative anti-pneumocystis readouts. We will prepare pcls (200-300 ΜM) from pneumocystis murina-infected lungs derived from aids-like CD4+- depleted mice and will assess viability and epithelial INTEGRITY13-15. We will also quantify reduced p. Murina burden by QPCR16,17 using benchmark anti-pneumocystis agents (e.g. pentamidine, TMP-SMX), and novel agents (ISFP10)18-20. Aim 2: integrate multiplexed host-response assessment to enable dual testing of agents for host inflammatory responses and anti-pneumocystis activity. Our preliminary data indicate that PCP pcls can recapitulate the antifungal activity of known anti-pneumocystis drugs (e.g., pentamidine) EX vivo and also measure host immune responses to anti-inflammatory agents 10,21,22,23,24. We will employ cytokine profiling (e.g., IL-6, IL-1Β, tnfa, IL-10) via LUMINEX25, confirmed by qpcr. Furthermore, we will evaluate small-molecule inhibitors targeting novel pneumocystis-induced host inflammatory signaling PATHWAYS10,12,26-30 during pcls INFECTION9. This approach will provide insight into the progression of infection and host immune responses and will be useful to identify agent that reduce fungal burden while tempering host inflammation. Exploratory aim 3: leverage the PCP pcls model for translational relevance by demonstrating that EX vivo PCP pcls reliably predicts conserved responses in human lung. We will assess the feasibility of generating human pcls from surgical tissue and subsequently expose the slices to p. Jirovecii derived from BAL28,31-36. We will quantify organism burden and host cytokine responses in the presence or absence of known and novel anti-pneumocystis and anti-inflammatory compounds in the EX vivo model of human PJP infection.