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result(s) for
"Martín-Fernández, Kevin"
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Explainable Automatic Detection of Fiber–Cement Roofs in Aerial RGB Images
2024
Following European directives, asbestos–cement corrugated roofing tiles must be eliminated by 2025. Therefore, identifying asbestos–cement rooftops is the first necessary step to proceed with their removal. Unfortunately, asbestos detection is a challenging task. Current procedures for identifying asbestos require human exploration, which is costly and slow. This has motivated the interest of governments and companies in developing automatic tools that can help to detect and classify these types of materials that are dangerous to the population. This paper explores multiple computer vision techniques based on Deep Learning to advance the automatic detection of asbestos in aerial images. On the one hand, we trained and tested two classification architectures, obtaining high accuracy levels. On the other, we implemented an explainable AI method to discern what information in an RGB image is relevant for a successful classification, ensuring that our classifiers’ learning process is guided by the right variables—color, surface patterns, texture, etc.—observable on asbestos rooftops.
Journal Article
Lysine methyltransferase 2D regulates pancreatic carcinogenesis through metabolic reprogramming
by
Huerta-Yepez, Sara
,
Fernández-Zapico, Martín E
,
Tirado-Rodriguez, Ana Belen
in
Animal models
,
Animals
,
Body mass index
2019
ObjectiveDespite advances in the identification of epigenetic alterations in pancreatic cancer, their biological roles in the pathobiology of this dismal neoplasm remain elusive. Here, we aimed to characterise the functional significance of histone lysine methyltransferases (KMTs) and demethylases (KDMs) in pancreatic tumourigenesis.DesignDNA methylation sequencing and gene expression microarrays were employed to investigate CpG methylation and expression patterns of KMTs and KDMs in pancreatic cancer tissues versus normal tissues. Gene expression was assessed in five cohorts of patients by reverse transcription quantitative-PCR. Molecular analysis and functional assays were conducted in genetically modified cell lines. Cellular metabolic rates were measured using an XF24-3 Analyzer, while quantitative evaluation of lipids was performed by liquid chromatography-mass spectrometry (LC-MS) analysis. Subcutaneous xenograft mouse models were used to evaluate pancreatic tumour growth in vivo.ResultsWe define a new antitumorous function of the histone lysine (K)-specific methyltransferase 2D (KMT2D) in pancreatic cancer. KMT2D is transcriptionally repressed in human pancreatic tumours through DNA methylation. Clinically, lower levels of this methyltransferase associate with poor prognosis and significant weight alterations. RNAi-based genetic inactivation of KMT2D promotes tumour growth and results in loss of H3K4me3 mark. In addition, KMT2D inhibition increases aerobic glycolysis and alters the lipidomic profiles of pancreatic cancer cells. Further analysis of this phenomenon identified the glucose transporter SLC2A3 as a mediator of KMT2D-induced changes in cellular, metabolic and proliferative rates.ConclusionTogether our findings define a new tumour suppressor function of KMT2D through the regulation of glucose/fatty acid metabolism in pancreatic cancer.
Journal Article
Tree-ring reconstructed dry season rainfall in Guatemala
by
Martin-Fernandez, Javier
,
Anchukaitis, Kevin J.
,
Taylor, Matthew J.
in
Abies guatemalensis
,
anthropogenic activities
,
Anthropogenic factors
2015
Drought in Guatemala has negative consequences for agriculture and potable water supplies, particularly in regions of the country with highly seasonal rainfall. General circulation models suggest that a decrease in both winter and summer rainfall over Central America is likely and imminent as a consequence of anthropogenic influences on the climate system. However, precipitation observations over the last several decades are equivocal. Here, we use an
Abies guatemalensis
tree-ring chronology from the Sierra de los Cuchumatanes to estimate January through March rainfall since the late seventeenth century. Our reconstruction shows that recent winter–spring rainfall from the region is not yet exceptional in the context of the last several centuries, has a significant yet variable decadal component, is associated with large-scale modes of ocean–atmosphere variability, and reveals evidence of past multiyear droughts.
Journal Article
Annual chronology and climate response in Abies guatemalensis Rehder (Pinaceae) in Central America
by
Anchukaitis, Kevin J
,
Martin-Fernandez, Javier
,
Castellanos, Edwin J
in
Abies guatemalensis
,
climate
,
Climate change
2013
The continued expansion of dendroclimatology into Mesoamerica requires the identification and evaluation of species whose rings can be precisely dated and then statistically compared with precipitation and temperature variability in order to make inferences about past climate. Here, we establish the basis for using Abies guatemalensis Rehder (Pinaceae) for climate reconstruction in Central America. Annual crossdating in this montane species is demonstrated at high-elevation sites in the Sierra de los Cuchumatanes in western Guatemala. We find that ring width is most strongly influenced by early growing season moisture conditions, controlled by late dry season rainfall, and negatively correlated with growing season temperature. Our chronology is also significantly negatively correlated with eastern tropical Pacific sea surface temperature anomalies. Our confirmation of annual chronology and the identification of a climatic signal in this species now allow its use in local and regional paleoclimate reconstructions, as well as ecological studies.
Journal Article
Reconstitution of human PDAC using primary cells reveals oncogenic transcriptomic features at tumor onset
2024
Animal studies have demonstrated the ability of pancreatic acinar cells to transform into pancreatic ductal adenocarcinoma (PDAC). However, the tumorigenic potential of human pancreatic acinar cells remains under debate. To address this gap in knowledge, we expand sorted human acinar cells as 3D organoids and genetically modify them through introduction of common PDAC mutations. The acinar organoids undergo dramatic transcriptional alterations but maintain a recognizable DNA methylation signature. The transcriptomes of acinar organoids are similar to those of disease-specific cell populations. Oncogenic
KRAS
alone do not transform acinar organoids. However, acinar organoids can form PDAC in vivo after acquiring the four most common driver mutations of this disease. Similarly, sorted ductal cells carrying these genetic mutations can also form PDAC, thus experimentally proving that PDACs can originate from both human acinar and ductal cells. RNA-seq analysis reveal the transcriptional shift from normal acinar cells towards PDACs with enhanced proliferation, metabolic rewiring, down-regulation of MHC molecules, and alterations in the coagulation and complement cascade. By comparing PDAC-like cells with normal pancreas and PDAC samples, we identify a group of genes with elevated expression during early transformation which represent potential early diagnostic biomarkers.
The cellular origin of human pancreatic ductal adenocarcinoma (PDAC) is still unclear. Here the authors used human primary acinar and ductal cells to successfully reconstitute PDAC tumorigenesis from both lineages and revealed transcriptional changes during early PDAC progression.
Journal Article
Autophagy receptor NDP52 alters DNA conformation to modulate RNA polymerase II transcription
2023
NDP52 is an autophagy receptor involved in the recognition and degradation of invading pathogens and damaged organelles. Although NDP52 was first identified in the nucleus and is expressed throughout the cell, to date, there is no clear nuclear functions for NDP52. Here, we use a multidisciplinary approach to characterise the biochemical properties and nuclear roles of NDP52. We find that NDP52 clusters with RNA Polymerase II (RNAPII) at transcription initiation sites and that its overexpression promotes the formation of additional transcriptional clusters. We also show that depletion of NDP52 impacts overall gene expression levels in two model mammalian cells, and that transcription inhibition affects the spatial organisation and molecular dynamics of NDP52 in the nucleus. This directly links NDP52 to a role in RNAPII-dependent transcription. Furthermore, we also show that NDP52 binds specifically and with high affinity to double-stranded DNA (dsDNA) and that this interaction leads to changes in DNA structure in vitro. This, together with our proteomics data indicating enrichment for interactions with nucleosome remodelling proteins and DNA structure regulators, suggests a possible function for NDP52 in chromatin regulation. Overall, here we uncover nuclear roles for NDP52 in gene expression and DNA structure regulation.
An autophagy receptor, NDP52, is recruited to the nucleus where it can bind DNA. The authors show this promotes changes in chromatin accessibility which supports transcription initiation, providing a direct link between autophagy and transcription regulation.
Journal Article
Estrogen receptor beta repurposes EZH2 to suppress oncogenic NFκB/p65 signaling in triple negative breast cancer
2022
Triple Negative Breast Cancer (TNBC) accounts for 15–20% of all breast cancer cases, yet is responsible for a disproportionately high percentage of breast cancer mortalities. Thus, there is an urgent need to identify novel biomarkers and therapeutic targets based on the molecular events driving TNBC pathobiology. Estrogen receptor beta (ERβ) is known to elicit anti-cancer effects in TNBC, however its mechanisms of action remain elusive. Here, we report the expression profiles of ERβ and its association with clinicopathological features and patient outcomes in the largest cohort of TNBC to date. In this cohort, ERβ was expressed in approximately 18% of TNBCs, and expression of ERβ was associated with favorable clinicopathological features, but correlated with different overall survival outcomes according to menopausal status. Mechanistically, ERβ formed a co-repressor complex involving enhancer of zeste homologue 2/polycomb repressive complex 2 (EZH2/PRC2) that functioned to suppress oncogenic NFκB/RELA (p65) activity. Importantly, p65 was shown to be required for formation of this complex and for ERβ-mediated suppression of TNBC. Our findings indicate that ERβ+ tumors exhibit different characteristics compared to ERβ− tumors and demonstrate that ERβ functions as a molecular switch for EZH2, repurposing it for tumor suppressive activities and repression of oncogenic p65 signaling.
Journal Article
Autoimmunity in Down’s syndrome via cytokines, CD4 T cells and CD11c+ B cells
by
Maillebouis, Louise
,
Malle, Louise
,
Trachtman, Rebecca
in
45/23
,
631/250/2152/569
,
631/250/248
2023
Down’s syndrome (DS) presents with a constellation of cardiac, neurocognitive and growth impairments. Individuals with DS are also prone to severe infections and autoimmunity including thyroiditis, type 1 diabetes, coeliac disease and alopecia areata
1
,
2
. Here, to investigate the mechanisms underlying autoimmune susceptibility, we mapped the soluble and cellular immune landscape of individuals with DS. We found a persistent elevation of up to 22 cytokines at steady state (at levels often exceeding those in patients with acute infection) and detected basal cellular activation: chronic IL-6 signalling in CD4 T cells and a high proportion of plasmablasts and CD11c
+
Tbet
high
CD21
low
B cells (Tbet is also known as TBX21). This subset is known to be autoimmune-prone and displayed even greater autoreactive features in DS including receptors with fewer non-reference nucleotides and higher
IGHV4-34
utilization. In vitro, incubation of naive B cells in the plasma of individuals with DS or with IL-6-activated T cells resulted in increased plasmablast differentiation compared with control plasma or unstimulated T cells, respectively. Finally, we detected 365 auto-antibodies in the plasma of individuals with DS, which targeted the gastrointestinal tract, the pancreas, the thyroid, the central nervous system, and the immune system itself. Together, these data point to an autoimmunity-prone state in DS, in which a steady-state cytokinopathy, hyperactivated CD4 T cells and ongoing B cell activation all contribute to a breach in immune tolerance. Our findings also open therapeutic paths, as we demonstrate that T cell activation is resolved not only with broad immunosuppressants such as Jak inhibitors, but also with the more tailored approach of IL-6 inhibition.
An autoimmune-prone state of steady-state cytokinopathy, hyperactivated CD4 T cells and ongoing B cell activation contributes to a breach in immune tolerance in individuals with Down’s syndrome.
Journal Article
Autophagy receptor NDP52 alters DNA conformation to modulate RNA Polymerase II transcription
NDP52 is an autophagy receptor involved in the recognition and degradation of invading pathogens and damaged organelles. Although NDP52 was first identified in the nucleus and is expressed throughout the cell, to date, there is no clear nuclear function for NDP52. Here, we use a multidisciplinary approach to characterise the biochemical properties and nuclear roles of NDP52. We found that NDP52 clusters with RNA Polymerase II (RNAPII) at transcription initiation sites and that its overexpression promotes the formation of additional transcriptional clusters. We also show that depletion of NDP52 impacts overall gene-expression levels in two model mammalian cells, and that transcription inhibition affects the spatial organisation and molecular dynamics of NDP52 in the nucleus. This directly links NDP52 to a role in RNAPII-dependent transcription. Furthermore, we also show that NDP52 binds specifically and with high affinity to double-stranded DNA (dsDNA) and that this interaction leads to changes in DNA structure in vitro. This, together with our proteomics data indicating enrichment for interactions with nucleosome remodelling proteins and DNA structure regulators, suggests a possible function for NDP52 in chromatin regulation. Overall, here we uncover novel nuclear roles for NDP52 in gene expression and DNA structure regulation.