Biology subjects

Brochiero, E.

Publications and source records attributed to Brochiero, E..

5 recordsLinked to original sources

bioRxiv2024

Sex and Disease Regulate MHC I Expression in Human Lung Epithelial Cells

Major histocompatibility complex class I (MHC I) molecules present endogenous peptides to CD8+ T-cells for immunosurveillance of infections and cancers. Recent studies revealed unexpected heterogeneity in MHC I expression among cells of different lineages. While respiratory diseases rank among the leading causes of mortality, studies in mice showed that lung epithelial cells (LECs) express lower MHC I levels than all other tested cell types. The present study aimed to evaluate MHC I expression in human LECs from parenchymal explants using single-cell RNA sequencing (scRNA-seq) and immunostaining of primary human LECs. After confirming the low constitutive MHC I expression in human LECs, we observed a significant upregulation of MHC I across three chronic respiratory diseases: chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and cystic fibrosis (CF). Additionally, we unveiled an unexpected sexual dimorphism in MHC I expression in both health and disease, with males exhibiting higher levels of MHC I under steady-state conditions. Gene expression analyses suggest that differential redox balance between sexes is instrumental in this dimorphism. Our study unveils the complex interplay between MHC I expression, sex, and respiratory diseases. Since, in other models, MHC I upregulation contributes to the development of immunopathologies, we propose that it might have a similar impact on chronic lung diseases. NEW & NOTEWORTHYThis study shows that MHC I expression is very low in healthy LECs but escalates significantly in three chronic respiratory diseases, potentially contributing to disease progression. Furthermore, sex-specific divergences in LEC MHC I levels hint at distinct susceptibilities to chronic lung inflammation between males and females. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/599895v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@44cfaborg.highwire.dtl.DTLVardef@19e1e29org.highwire.dtl.DTLVardef@1ce179aorg.highwire.dtl.DTLVardef@16f8063_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Intracellular Pseudomonas aeruginosa within the airway epithelium of Cystic Fibrosis lung tissues

RATIONALEPseudomonas aeruginosa (P.a.) is the major bacterial pathogen colonizing the airways of adult cystic fibrosis (CF) patients and causes chronic infections that persist despite antibiotic therapy. Intracellular bacteria may represent an unrecognized reservoir of bacteria that evades the immune system and antibiotic therapy. While the ability of P.a. to invade and survive within epithelial cells has been described in vitro in different epithelial cell models, evidence of this intracellular lifestyle in human lung tissues is currently lacking. OBJECTIVESTo detect and characterize intracellular P.a. in CF airway epithelium from human lung explant tissues. METHODSWe sampled the lung explant tissues from CF and non-CF patients undergoing lung transplantation and analyzed lung tissue sections for the presence of intracellular P.a. by quantitative culture and microscopy, in parallel to histopathology and airway morphometry. MEASUREMENTS AND MAIN RESULTSP.a. was isolated from the lungs of 7 CF patients undergoing lung transplantation. Microscopic assessment revealed the presence of intracellular P.a. within airway epithelial cells in 3 out of the 7 lungs analyzed, at a varying but rare frequency. We observed those events occurring in lung regions with high bacterial burden. CONCLUSIONThis is the first study describing the presence of intracellular P.a. in CF lung tissues. While intracellular P.a. in airway epithelial cells are likely relatively rare events, our findings highlight the plausible occurrence of this intracellular bacterial reservoir in chronic CF infections.

microbiology↗

bioRxiv2022

High Quality Phasing Using Linked-Read Whole Genome Sequencing of Patient Cohorts Informs Genetic Understanding of Complex Traits

Phasing of heterozygous alleles is critical for interpretation of cis-effects of disease-relevant variation. For population studies, phase is often inferred from external data but read-based phasing approaches that span long genomic distances would be more accurate because they enable both genotype and phase to be obtained from a single dataset. To demonstrate how read-based phasing can provide functional insights, we sequenced 477 individuals with Cystic Fibrosis (CF) using linked-read sequencing. We benchmark read-based phasing with different short- and long-read sequencing technologies, prioritize linked-read technology as the most informative and produce a benchmark phase call set from reference sample HG002 for the community. The 477 samples display an average phase block N50 of 4.39 Mb. We use these samples to construct a graph representation of CFTR haplotypes, which facilitates understanding of complex CF alleles. Fine-mapping and phasing of the chr7q35 trypsinogen locus associated with CF meconium ileus demonstrates a 20 kb deletion and a PRSS2 missense variant p.Thr8Ile (rs62473563) independently contribute to meconium ileus risk (p=0.0028, p=0.011, respectively) and are PRSS2 pancreas eQTLs (p=9.5e-7 and p=1.4e-4, respectively), explaining the mechanism by which these polymorphisms contribute to CF. Phase enables access to haplotypes that can be used for genome graph or reference panel construction, identification of cis-effects, and for understanding disease associated loci. The phase information from linked-reads provides a causal explanation for variation at a CF-relevant locus which also has implications for the genetic basis of non-CF pancreatitis to which this locus has been reported to contribute.

genetics↗

bioRxiv2021

Impact of temperature on the affinity of SARS-CoV-2 Spike for ACE2

The seasonal nature in the outbreaks of respiratory viral infections with increased transmission during low temperatures has been well established. The current COVID-19 pandemic makes no exception, and temperature has been suggested to play a role on the viability and transmissibility of SARS-CoV-2. The receptor binding domain (RBD) of the Spike glycoprotein binds to the angiotensin-converting enzyme 2 (ACE2) to initiate viral fusion. Studying the effect of temperature on the receptor-Spike interaction, we observed a significant and stepwise increase in RBD-ACE2 affinity at low temperatures, resulting in slower dissociation kinetics. This translated into enhanced interaction of the full Spike to ACE2 receptor and higher viral attachment at low temperatures. Interestingly, the RBD N501Y mutation, present in emerging variants of concern (VOCs) that are fueling the pandemic worldwide, bypassed this requirement. This data suggests that the acquisition of N501Y reflects an adaptation to warmer climates, a hypothesis that remains to be tested.

microbiology↗

bioRxiv2017

DUSP1 promotes apoptosis and suppresses cell migration, while leaving the JIP1-protected cytokine production intact, during paramyxovirus infection.

The host antiviral response involves the induction of interferons and proinflammatory cytokines, but also the activation of cell death pathways, including apoptosis, to limit viral replication and spreading. This host defense is strictly regulated to eliminate the infection while limiting tissue damage that is associated with virus pathogenesis. Post-translational modifications, most notably phosphorylation, are key regulators of the antiviral defense implying an important role of protein phosphatases. Here, we investigated the role of the dual-specificity phosphatase 1 (DUSP1) in the host defense against human respiratory syncytial virus (RSV), a pathogenic virus of the Pneumoviridae family, and Sendai virus (SeV), a model virus being developed as a vector for anti-RSV vaccine. We found that DUSP1 is upregulated before being subjected to proteasomal degradation. DUSP1 does not inhibit the antiviral response, but negatively regulates virus-induced JNK/p38 MAPK phosphorylation. Interaction with the JNK-interacting protein 1 scaffold protein prevents dephosphorylation of JNK by DUSP1, likely explaining that AP-1 activation and downstream cytokine production are protected from DUSP1 inhibition. Importantly, DUSP1 promotes SeV-induced apoptosis and suppresses cell migration in RSV-infected cells. Collectively, our data unveil a previously unrecognized selective role of DUSP1 in the regulation of tissue damage and repair during infections by RSV and SeV.

microbiology↗