Biology subjects

Bruscia, E. M.

Publications and source records attributed to Bruscia, E. M..

5 recordsLinked to original sources

bioRxiv2026

An N, S-acetylated L-cysteine-cysteamine conjugate hinders pyocyanin redox cycling to weaken Pseudomonas aeruginosa biofilm and dampens LPS-driven acute pulmonary inflammation

The persistence of P. aeruginosa infections is largely driven by the secretion of several factors during invasion, including the redox-active phenazine pyocyanin (PYO), which promotes biofilm formation and oxidative stress. Biofilms contribute to chronic infections and antibiotic resistance, limiting the efficacy of conventional therapies. We found that a synthetic compound, I-152, a conjugate of N-acetyl-L-cysteine (NAC) and S-acetylcysteamine (also known as S-acetyl-{beta}-mercaptoethylamine; SMEA), effectively restored colistin susceptibility against P. aeruginosa by altering biofilm nanomechanical properties. These perturbations in matrix integrity were associated with I-152s ability to hinder the phenazine redox cycle, shifting PYO to a reduced state as well as enabling S-conjugate formation. The compound decreased PYO accumulation in bacterial cultures and PYO-generated reactive oxygen species (ROS) in macrophage cells. Together with PYO, LPS is another driver of ROS-dependent inflammatory signaling in the host, which leads to an uncontrolled cytokine response and organ damage, especially in patients with cystic fibrosis. I-152 treatment downregulated the expression of LPS-induced inflammatory cytokines, i.e., IL-6 and TNF-, in bone marrow-derived macrophages (BMDM) isolated from transgenic CFTR-/- and CFTR+/+ mice. Consistently, I-152 partially counteracted the inflammatory response in the P. aeruginosa LPS-induced acute lung injury murine model. Taken together, these results support I-152 as an adjunctive treatment for P. aeruginosa respiratory infections through a dual mechanism: combating antimicrobial resistance in biofilms and dampening host inflammation in the respiratory system. HighlightsO_LII-152 potentiates colistin activity against P. aeruginosa by compromising the biofilm surface C_LIO_LII-152 rewires the pyocyanin (PYO) redox state and forms covalent adducts with it C_LIO_LIPYO accumulation and PYO-induced ROS generation in macrophages is impaired by I-152 C_LIO_LIEx vivo, I-152 dampens excessive pro-inflammatory response to P. aeruginosa LPS in CFTR-/- and CFTR+/+ BM-derived macrophages C_LIO_LII-152 (140 mg/Kg) attenuates LPS-driven inflammation and lung damage in CFTR+/+ mice C_LI

pharmacology and toxicology↗

bioRxiv2024

ENaC contributes to macrophage dysfunction in cystic fibrosis

BackgroundCystic fibrosis (CF) is a chronic systemic disease caused by dysfunctional or absent cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is expressed in human immune cells and plays a role in regulating innate immunity both directly and indirectly. Besides CFTR, research indicates that the epithelial sodium channel (ENaC) also contributes to dysfunction in CF airway epithelial cells. However, the impact of non-CFTR ion channel dysfunction on CF immune responses is not yet fully understood. A precise understanding of how CF immune function is regulated by ion channels may allow antibiotic-and mutation-agnostic treatment approaches to chronic bacterial infection and inflammation. Therefore, we hypothesized that ENaC is aberrantly expressed in CF macrophages and directly contributes to impaired phagocytic and inflammatory functions. MethodsENaC expression was characterized in human immune cells isolated from CF and non-CF blood donors. Monocyte-derived macrophage (MDM) function and bacterial killing was tested in the setting of ENaC modulation. ResultsBaseline expression of ENaC in human CF MDMs, lymphocytes, and granulocytes was increased at both the transcript and protein level relative to non-CF controls and persisted after exposure to bacteria. Inhibition of CFTR in non-CF MDMs resulted in ENaC overexpression. CFTR modulator treatment reduced but did not eliminate ENaC overexpression in CF MDMs. Interestingly, ENaC inhibition with Amiloride increased CFTR expression. Amiloride-treated CF MDMs also showed normalized ROS production, improved autophagy, and decreased pro-inflammatory cytokine production. Finally, results from an ion channel microarray indicated that sodium channel expression in CF MDMs normalized after Amiloride treatment with minimal effect on other ion channels. DiscussionENaC is overexpressed in CF immune cells and is associated with abnormal macrophage function. ENaC modulation in immune cells is a novel potential therapeutic target for infection control in CF, either in combination with CFTR modulators, or as a sole agent for patients not currently eligible for CFTR modulators.

immunology↗

bioRxiv2024

CHRONIC LUNG INFLAMMATION LEADS TO MYELOID SKEWING OF HEMATOPOIETIC STEM CELLS IN A CYSTIC FIBROSIS MOUSE MODEL

Persistent lung inflammation is a hallmark of Cystic fibrosis (CF) lung disease. Inflammation can lead to functional decline in hematopoietic stem cell (HSCs), tipping the balance towards myelopoiesis and contributing to chronic inflammation. However, its unknown whether the HSCs are dysfunctional in CF. We tested whether chronic lung inflammation impacts hematopoietic stem and progenitor cells (HSPCs) in a CF mouse model. Wild-type (WT) and Cftr-/- mice were nebulized with lipopolysaccharide (LPS) from Pseudomonas aeruginosa for 5 weeks. The mice were euthanized before the exposure (T0), 24 hours after the last LPS nebulization (T1), or 6 weeks (T2) after the last LPS nebulization. The bone marrow (BM) and lung tissue were collected for flow cytometry analysis of the HSPC population and immune cells in the lungs, respectively. Peripheral blood was collected for complete blood count analysis. At baseline, Cftr-/- mice show a larger HSPC population with a myeloid bias, indicated by higher frequencies of LSK, LT-HSC, CD41+ LT-HSC, GMPs, and MkPs. Following chronic LPS nebulization, Cftr-/- mice exhibit greater HSPC expansion and myeloid differentiation, alongside increased peripheral myeloid cell counts. Post-recovery, while most HSPC populations return to baseline, Cftr-/- mice retain elevated myeloid-biased LT-HSCs, suggesting a persistent myeloid bias. These findings underscore a prominent shift toward myeloid hematopoiesis in CF, which is accentuated by chronic inflammation and remains even after recovery. Further experiments are underway to assess maladaptive epigenetic changes in HSC as well as if chronic lung inflammation impacts HSC functionality.

immunology↗

bioRxiv2022

Human neutrophil development and functionality are enabled in a humanized mouse model

Mice with a functional human immune system serve as an invaluable tool to study the development and function of human immune system in vivo. A major technological limitation of all current humanized mouse models is the lack of mature and functional human neutrophils in circulation and tissues. To overcome this, we generated a humanized mouse model named MISTRGGR, in which the mouse granulocyte colony stimulating factor (G-CSF) was replaced with human G-CSF and the mouse G-CSF receptor gene was deleted (G-CSFR) in existing MISTRG mice. By targeting the GCSF cytokine-receptor axis, we dramatically improved the reconstitution of mature circulating and tissue-infiltrating human neutrophils in MISTRGGR mice. Moreover, these functional human neutrophils in MISTRGGR are recruited upon inflammatory and infectious challenges and help reduce bacterial burden. MISTRGGR mice represent a unique mouse model that finally permits the study of human neutrophils in health and disease. Key PointsO_LITargeting the GCSF cytokine-receptor axis dramatically improves circulating and tissue-infiltrating human neutrophils in MISTRGGR mice. C_LIO_LIHuman neutrophils generated in MISTRGGR mice are functional and are able to respond robustly to inflammatory and infectious stimuli. C_LI

immunology↗

bioRxiv2018

A Highly Efficient and Faithful MDS Patient-Derived Xenotransplantation Model for Pre-Clinical Studies

Comprehensive preclinical studies of Myelodysplastic Syndromes (MDS) have been elusive due to limited ability of MDS stem cells to engraft current immunodeficient murine hosts. We developed a novel MDS patient-derived xenotransplantation model in cytokine-humanized immunodeficient \"MISTRG\" mice that for the first time provides efficient and faithful disease representation across all MDS subtypes. MISTRG MDS patient-derived xenografts (PDX) reproduce patients' dysplastic morphology with multi-lineage representation, including erythro- and megakaryopoiesis. MISTRG MDS-PDX replicate the original sample's genetic complexity and can be propagated via serial transplantation. MISTRG MDS-PDX demonstrate the cytotoxic and differentiation potential of targeted therapeutics providing superior readouts of drug mechanism of action and therapeutic efficacy. Physiologic humanization of the hematopoietic stem cell niche proves critical to MDS stem cell propagation and function in vivo. The MISTRG MDS-PDX model opens novel avenues of research and long-awaited opportunities in MDS research.

cancer biology↗