Biology subjects

Cabrera, C.

Publications and source records attributed to Cabrera, C..

6 recordsLinked to original sources

bioRxiv2026

A tumor-cell MHC-II program is associated with checkpoint-blockade outcomes across stages of bladder cancer

Purpose: A minority of patients with bladder cancer derive lasting benefit from immunotherapy, and current biomarkers capture only part of the biology. We evaluated whether tumor-cell MHC class II defines an immune state associated with outcome across disease stages and after PD-1/PD-L1 blockade. Experimental Design: We localized differential MHC-II activity to malignant epithelial cells by single-nucleus and single-cell RNA sequencing and confirmed HLA-DR expression by immunohistochemistry in 122 specimens. Chromatin profiling and IFN-{gamma} stimulation of cell lines and primary tumors supported derivation of an 11-gene tumor-cell program. Associations were tested in 434 patients with non-muscle-invasive disease, 82 receiving neoadjuvant pembrolizumab, and 288 receiving atezolizumab for metastatic disease. Results: Tumor-cell MHC-II was present in approximately one third of bladder cancers, and malignant cells accounted for the differential signal between MHC-II-high and MHC-II-low tumors. The program was inducible by IFN-{gamma} through JAK/STAT signaling. Within luminal non-muscle-invasive disease, MHC-II-low status was associated with progression (HR 3.31, 95% CI 1.37 to 7.99). In PURE-01, the 11-gene program was associated with pathological complete response (52% versus 24%, p = 0.018) and recurrence-free survival (p = 0.0054), retaining an independent association in models including tumor mutational burden and PD-L1. In bladder-primary metastatic disease, program-high status was associated with overall survival in unadjusted analysis (HR 0.62, 95% CI 0.44 to 0.89); the association did not extend to upper tract tumors (interaction p = 0.0018). Conclusions: Tumor-cell MHC-II defines an inducible state associated with outcomes across bladder cancer stages and after checkpoint blockade, supporting prospective evaluation by RNA and immunohistochemistry.

cancer biology↗

bioRxiv2022

Over the hills and far away: landscape factors affecting cavity digging by the Black woodpecker (Dryocopus martius, L. 1758)

The Black Woodpecker (Dryocopus martius, L. 1758) is the largest primary cavity excavator in Europe. Its cavities represent an essential microhabitat for many other forest species and the knowledge on landscape factors linked with cavity excavation by the Black Woodpecker is needed to support the conservation of this species and associated species. Such relationships should thus be quantified at different scales ranging from the stand to the extended home range. We used cavity maps established by foresters and naturalists to build a large (2689 cavity bearing trees) database distributed over several sites in France. Based on this and on a set of background points, i.e. randomly selected points devoid of cavity in the vicinity, we analysed the effects of stand composition and landscape features (forest cover, forest connectivity and fragmentation) at three different scales around each cavity and background point corresponding to a forest management unit (10ha), the core (100ha) and extended (250ha) home range scales. We showed that indices describing forest continuity (cohesion, landscape shape index) and forest tree species composition (especially the presence of mixed forests) had significant positive effects but that the magnitude varied across the three scales. We notably observed the strongest effects at the core home range scale (100ha), indicating that Black Woodpecker requirements for cavity excavation are more pronounced at this scale. The Black Woodpecker tends to avoid pure conifer-dominated stands to excavate cavities, but benefits from mixed forests, that couple favourable foraging and cavity excavation sites. The bird also prefers continuous forest landscapes with high cohesion and low edge densities. We also showed that the positive effects of forest landscape were generally at higher elevation, indicating context-dependence. Forest planning rarely integrates the landscape patterns. A better understanding of the features linked with cavity excavation by the Black Woodpecker may hence help to better integrate their conservation in forest management planning. Our results also show the importance to maintain mixed broadleaf-conifer forests as well as continuous and well-connected forest landscapes to favour features that benefit primary and secondary cavity nesters.

ecology↗

bioRxiv2020

SARS-CoV-2 infection suppresses ACE2 function and antiviral immune response in the upper respiratory tract of infected patients

There is an urgent need to elucidate the molecular mechanisms underlying the transmissibility and pathogenesis of SARS-CoV-2. ACE2 is a host ectopeptidase with well-described anti-inflammatory and tissue protective functions and the receptor for the virus. Understanding SARS-CoV-2-ACE2 interaction and the expression of antiviral host genes in early infection phase is crucial for fighting the pandemic. We tested the significance of soluble ACE2 enzymatic activity longitudinally in positive nasopharyngeal swabs at two time points after symptom consultation, along with gene expression profiles of ACE2, its proteases, ADAM17 and TMPRRS2, and interferon-stimulated genes (ISGs), DDX58, CXCL10 and IL-6. Soluble ACE2 activity decreased during infection course, in parallel to ACE2 gene expression. On the contrary, SARS-CoV-2 infection induced expression of the ISG genes in positive SARS-CoV-2 samples at baseline compared to negative control subjects, although this increase wanes with time. These changes positively correlated with viral load. Our results demonstrate the existence of mechanisms by which SARS-CoV-2 suppress ACE2 expression and function casting doubt on the IFN-induced upregulation of the receptor. Moreover, we show that initial intracellular viral sensing and subsequent ISG induction is also rapidly downregulated. Overall, our results offer new insights into ACE2 dynamics and inflammatory response in the human upper respiratory tract that may contribute to understand the early antiviral host response to SARS-CoV-2 infection.

immunology↗

bioRxiv2019

Enzymatic degradation of RNA causes widespread protein aggregation in cell and tissue lysates

Most proteins in cell and tissue lysates are soluble. Here, we show that many of these proteins, including several that are implicated in neurodegenerative diseases, are maintained in a soluble and functional state by association with endogenous RNA, as degradation of RNA invariably leads to protein aggregation. We identify the importance of nucleic acid structure, with single-stranded pyrimidine-rich bulges or loops surrounded by double-stranded regions being particularly efficient in this role, revealing an apparent one-to-one protein-nucleic acid stoichiometry. The relationship of these findings to pathological protein aggregation is suggested by our discovery that protein aggregates isolated from brain tissue from Amyotrophic Lateral Sclerosis patients can be rendered soluble after refolding by both RNA and synthetic oligonucleotides. Together, these findings open new avenues for understanding the mechanism behind protein aggregation and shed light on how certain proteins remain soluble.

molecular biology↗

bioRxiv2019

KCND3 is a novel susceptibility locus for early repolarization

The presence of an early repolarization pattern (ERP) on the surface electrocardiogram (ECG) is associated with risk of ventricular fibrillation and sudden cardiac death. Family studies have shown that ERP is a highly heritable trait but molecular genetic determinants are unknown. We assessed the ERP in 12-lead ECGs of 39,456 individuals and conducted a two-stage meta-analysis of genome-wide association studies (GWAS). In the discovery phase, we included 2,181 cases and 23,641 controls from eight European ancestry studies and identified 19 genome-wide significant (p<5E-8) variants in the KCND3 (potassium voltage gated channel subfamily D member 3) gene with a p-value of 4.6E-10. Replication of two loci in four additional studies including 1,124 cases and 12,510 controls confirmed the association at the KCND3 gene locus with a pooled odds ratio of 0.82, p=7.7E-12 (rs1545300 minor allele T). A subsequent GWAS meta-analysis combining all samples did not reveal additional loci. The lead SNP of the discovery stage (rs12090194) was in strong linkage disequilibrium with rs1545300 (r2=0.96, D=1). Summary statistics based conditional analysis did not reveal any secondary signals. Co-localization analyses indicate causal effects of KCND3 gene expression levels on ERP in both the left ventricle of the heart and in tibial artery.\n\nIn this study we identified for the first time a genome-wide significant association of a genetic variant with ERP. Our findings of a locus in the KCND3 gene not only provide insights into the genetic determinants but also into the pathophysiological mechanism of ERP, revealing a promising candidate for functional studies.

genetics↗

bioRxiv2017

Detecting pathogen exposure during the non-symptomatic incubation period using physiological data

Early pathogen exposure detection allows better patient care and faster implementation of public health measures (patient isolation, contact tracing). Existing exposure detection most frequently relies on overt clinical symptoms, namely fever, during the infectious prodromal period. We have developed a robust machine learning based method to better detect asymptomatic states during the incubation period using subtle, sub-clinical physiological markers. Starting with high-resolution physiological waveform data from non-human primate studies of viral (Ebola, Marburg, Lassa, and Nipah viruses) and bacterial (Y. pestis) exposure, we processed the data to reduce short-term variability and normalize diurnal variations, then provided these to a supervised random forest classification algorithm and post-classifier declaration logic step to reduce false alarms. In most subjects detection is achieved well before the onset of fever; subject cross-validation across exposure studies (varying viruses, exposure routes, animal species, and target dose) lead to 51h mean early detection (at 0.93 area under the receiver-operating characteristic curve [AUCROC]). Evaluating the algorithm against entirely independent datasets for Lassa, Nipah, and Y. pestis exposures un-used in algorithm training and development yields a mean 51h early warning time (at AUCROC=0.95). We discuss which physiological indicators are most informative for early detection and options for extending this capability to limited datasets such as those available from wearable, non-invasive, ECG-based sensors.

physiology↗