Biology subjects

Partida-Sanchez, S.

Publications and source records attributed to Partida-Sanchez, S..

4 recordsLinked to original sources

bioRxiv2026

Gelsolin protects mitochondria and regulates inflammation during Legionella pneumophila infection

Legionella pneumophila (L. pneumophila) is the causative agent of Legionnaires' disease, a severe bacterial pneumonia. Difficulty in diagnosing Legionnaires' disease leads to an underreporting of cases and delayed treatment. Rapid-acting, broad-spectrum therapies are needed to treat pathology while avoiding antibiotic resistance. We showed that gelsolin knockout (gsn-/-) mice succumb more quickly to severe L. pneumophila infection despite no difference in bacterial loads in the lung compared to wild type mice. There is an increase in CXCL1/KC production from macrophages from gsn-/- mice, which is accompanied by increased neutrophils and apoptosis in their lungs. Neutrophils lacking gelsolin produce fewer neutrophil extracellular traps, and their mitochondrial capacity is diminished in response to L. pneumophila. Gelsolin is required for maintaining mitochondrial network morphology and respiration in L. pneumophila infected macrophages. When given recombinant gelsolin protein, gsn-/- mice survive significantly longer during severe L. pneumophila infection, with reduced lung pathology, and the inflammatory signature of their macrophages was reduced in vitro. Together, gelsolin protects mice during severe L. pneumophila infection, dampens inflammation, promotes mitochondrial health, and maintains neutrophil function.

immunology↗

bioRxiv2025

CFTR mutation leads to intrinsic dysfunction in neutrophils from people with Cystic Fibrosis

Cystic fibrosis (CF), a common genetic disease, is caused by a defective CF-transmembrane conductance regulator (CFTR). People with CF (pwCF) are prone to develop infections by opportunistic pathogens, including Burkholderia cenocepacia, leading to chronic inflammation and lung function loss. Neutrophils, the most abundant cells in the chronically inflamed lungs of pwCF, release granular proteins and oxidative products that contribute to tissue damage. The CFTR modulators are a new treatment for pwCF aiming to correct the subcellular location and function of the CFTR ion channel. The triple modulator combination of Elexacaftor, Tezacaftor, and Ivacaftor (ETI) or Trikafta(R) has significantly improved clinical symptoms and overall provided a better quality of life for pwCF. The mechanism by which the CFTR modulators help to restore the antimicrobial functions of neutrophils is unknown. The present study demonstrates that neutrophils functionally express CFTR and reveals how ETI modifies subcellular CFTR trafficking in CF neutrophils. In addition, ETI treatment reduces intracellular chloride levels in human neutrophils, indicating activation of CFTR-dependent chloride efflux (outflow). Finally, ETI treatment also reestablished the intracellular antimicrobial killing of CF neutrophils by potentiating NADPH oxidase activity and producing Neutrophil Extracellular Traps (NETs). Together, our findings suggest that CFTR has an essential role in controlling neutrophil functions and that the CFTR modulators improve the health of pwCF by restoring the antimicrobial functions of CF neutrophils. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/656500v1_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@8469b5org.highwire.dtl.DTLVardef@1380609org.highwire.dtl.DTLVardef@1145117org.highwire.dtl.DTLVardef@d7c0a2_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract.C_FLOATNO (A) The F508del defective CFTR protein cannot reach the plasma membrane in CF neutrophils, which increases the intracellular concentrations of Cl- ions, and allows other ions to be internalized, including Na+ and Ca2+. This ionic imbalance affects the NADPH oxidase, leading to a reduced preactivation response and consequently impacting NADPH oxidase-dependent antimicrobial mechanisms, including intracellular antimicrobial killing and NETosis. (B) Treating with ETI restores the CFTR expression in the plasma membrane of CF neutrophils, increasing the Cl- efflux and regulating the intracellular levels of Na+ and Ca2+, leading to correcting the NADPH oxidase, which results in potentiating the intracellular antimicrobial killing and NETosis. BiorenderTM tools generated the images. C_FIG

immunology↗

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↗

bioRxiv2021

Caspase-4/11 exacerbates disease severity in SARS-CoV-2 infection by promoting inflammation and thrombosis

SARS-CoV-2 is a worldwide health concern, and new treatment strategies are needed 1. Targeting inflammatory innate immunity pathways holds therapeutic promise, but effective molecular targets remain elusive. Here, we show that human caspase-4 (CASP4), and its mouse homologue, caspase-11 (CASP11), are upregulated in SARS-CoV-2 infections, and that CASP4 expression correlates with severity of SARS-CoV-2 infection in humans. SARS-CoV-2-infected Casp11-/- mice were protected from severe weight loss and lung pathology, including blood vessel damage, compared to wild-type (WT) and gasdermin-D knock out (Gsdmd-/-) mice. GSDMD is a downstream effector of CASP11 and CASP1. Notably, viral titers were similar in the three genotypes. Global transcriptomics of SARS-CoV-2-infected WT, Casp11-/- and Gsdmd-/- lungs identified restrained expression of inflammatory molecules and altered neutrophil gene signatures in Casp11-/- mice. We confirmed that protein levels of inflammatory mediators IL-1{beta}, IL6, and CXCL1, and neutrophil functions, were reduced in Casp11-/- lungs. Additionally, Casp11-/- lungs accumulated less von Willebrand factor, a marker for endothelial damage, but expressed more Kruppel-Like Factor 2, a transcription factor that maintains vascular integrity. Overall, our results demonstrate that CASP4/11, promotes detrimental SARS-CoV-2-associated inflammation and coagulopathy, largely independently of GSDMD, identifying CASP4/11 as a promising drug target for treatment and prevention of severe COVID-19.

immunology↗