Biology subjects

Gonzalez-Gonzalez, F. J.

Publications and source records attributed to Gonzalez-Gonzalez, F. J..

4 recordsLinked to original sources

bioRxiv2023

Myosin Light Chain Dephosphorylation by PPP1R12C Promotes Atrial Hypocontractility in Atrial Fibrillation

BackgroundAtrial fibrillation (AF), the most common sustained cardiac arrhythmia, increases thromboembolic stroke risk five-fold. Although atrial hypocontractility contributes to stroke risk in AF, the molecular mechanisms reducing myofilament contractile function remain unknown. We tested the hypothesis that increased expression of PPP1R12C, the PP1 regulatory subunit targeting atrial myosin light chain 2 (MLC2a), causes hypophosphorylation of MLC2a and results in atrial hypocontractility. MethodsRight atrial appendage tissues were isolated from human AF patients versus sinus rhythm (SR) controls. Western blots, co-immunoprecipitation, and phosphorylation studies were performed to examine how the PP1c-PPP1R12C interaction causes MLC2a de-phosphorylation. In vitro studies of pharmacologic MRCK inhibitor (BDP5290) in atrial HL-1 cells were performed to evaluate PP1 holoenzyme activity on MLC2a. Cardiac-specific lentiviral PPP1R12C overexpression was performed in mice to evaluate atrial remodeling with atrial cell shortening assays, echocardiography, and AF inducibility with EP studies. ResultsIn human patients with AF, PPP1R12C expression was increased two-fold versus SR controls (P=2.0x10-2, n=12,12 in each group) with > 40% reduction in MLC2a phosphorylation (P=1.4x10-6, n=12,12 in each group). PPP1R12C-PP1c binding and PPP1R12C-MLC2a binding were significantly increased in AF (P=2.9x10-2 and 6.7x10-3 respectively, n=8,8 in each group). In vitro studies utilizing drug BDP5290, which inhibits T560-PPP1R12C phosphorylation, demonstrated increased PPP1R12C binding with both PP1c and MLC2a, and dephosphorylation of MLC2a. Lenti-12C mice demonstrated a 150% increase in LA size versus controls (P=5.0x10-6, n=12,8,12), with reduced atrial strain and atrial ejection fraction. Pacing-induced AF in Lenti-12C mice was significantly higher than controls (P=1.8x10-2 and 4.1x10-2 respectively, n= 6,6,5). ConclusionsAF patients exhibit increased levels of PPP1R12C protein compared to controls. PPP1R12C overexpression in mice increases PP1c targeting to MLC2a and causes MLC2a dephosphorylation, which reduces atrial contractility and increases AF inducibility. These findings suggest that PP1 regulation of sarcomere function at MLC2a is a key determinant of atrial contractility in AF.

molecular biology↗

bioRxiv2023

Myeloid Zfhx3 Deficiency Protects Against Hypercapnia-induced Suppression of Host Defense Against Influenza A Virus

Hypercapnia, elevation of the partial pressure of CO2 in blood and tissues, is a risk factor for mortality in patients with severe acute and chronic lung diseases. We previously showed that hypercapnia inhibits multiple macrophage and neutrophil antimicrobial functions, and that elevated CO2 increases the mortality of bacterial and viral pneumonia in mice. Here, we show that normoxic hypercapnia downregulates innate immune and antiviral gene programs in alveolar macrophages (AMOs). We also show that zinc finger homeobox 3 (Zfhx3), mammalian ortholog of zfh2, which mediates hypercapnic immune suppression in Drosophila, is expressed in mouse and human MOs. Deletion of Zfhx3 in the myeloid lineage blocked the suppressive effect of hypercapnia on immune gene expression in AMOs and decreased viral replication, inflammatory lung injury and mortality in hypercapnic mice infected with influenza A virus. Our results establish Zfhx3 as the first known mammalian mediator of CO2 effects on immune gene expression and lay the basis for future studies to identify therapeutic targets to interrupt hypercapnic immunosuppression in patients with advanced lung diseases. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=151 SRC="FIGDIR/small/530480v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@f6f907org.highwire.dtl.DTLVardef@577795org.highwire.dtl.DTLVardef@6c0068org.highwire.dtl.DTLVardef@8ebb72_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2020

Hypercapnia Suppresses Macrophage Antiviral Activity and Increases Mortality of Influenza A 1 Infection via Akt1

Hypercapnia, elevation of the partial pressure of CO2 in blood and tissues, is a risk factor for mortality in patients with severe acute and chronic lung diseases. We previously showed that hypercapnia inhibits multiple macrophage and neutrophil antimicrobial functions, and that it increases the mortality of bacterial pneumonia in mice. Here, we show that normoxic hypercapnia increases viral replication, lung injury and mortality in mice infected with influenza A virus (IAV). Elevated CO2 increased IAV replication and inhibited antiviral gene and protein expression in macrophages in vivo and in vitro. Hypercapnia potentiated IAV-induced activation of Akt, while specific pharmacologic inhibition or shRNA knockdown of Akt1 in alveolar macrophages blocked hypercapnias effects on IAV growth and the macrophage antiviral response. Our findings suggest that targeting Akt1 or downstream pathways through which elevated CO2 signals could enhance macrophage antiviral host defense and improve clinical outcomes in hypercapnic patients with advanced lung disease.

immunology↗

bioRxiv2018

Single-Cell Transcriptomic Analysis of Human Lung Reveals Complex Multicellular Changes During Pulmonary Fibrosis

Pulmonary fibrosis is a devastating disorder that results in the progressive replacement of normal lung tissue with fibrotic scar. Available therapies slow disease progression, but most patients go on to die or require lung transplantation. Single-cell RNA-seq is a powerful tool that can reveal cellular identity via analysis of the transcriptome, but its ability to provide biologically or clinically meaningful insights in a disease context is largely unexplored. Accordingly, we performed single-cell RNA-seq on lung tissue obtained from eight transplant donors and eight recipients with pulmonary fibrosis and one bronchoscopic cryobiospy sample. Integrated single-cell transcriptomic analysis of donors and patients with pulmonary fibrosis identified the emergence of distinct populations of epithelial cells and macrophages that were common to all patients with lung fibrosis. Analysis of transcripts in the Wnt pathway suggested that within the same cell type, Wnt secretion and response are restricted to distinct non-overlapping cells, which was confirmed using in situ RNA hybridization. Single-cell RNA-seq revealed heterogeneity within alveolar macrophages from individual patients, which was confirmed by immunohistochemistry. These results support the feasibility of discovery-based approaches applying next generation sequencing technologies to clinically obtained samples with a goal of developing personalized therapies.\n\nOne Sentence SummarySingle-cell RNA-seq applied to tissue from diseased and donor lungs and a living patient with pulmonary fibrosis identifies cell type-specific disease-associated molecular pathways.

systems biology↗