Search bioRxiv⌕ Search

Biology subjects

Hernandez-Vargas, H.

Publications and source records attributed to Hernandez-Vargas, H..

15 recordsLinked to original sources

Characterisation of CD4 Th subsets as well as dietary, exercise and lifestyle factors in an established Rheumatoid Arthritis cohort; pilot study.

BackgroundSex disparities in the incidence and severity of Rheumatoid Arthritis (RA) are well-documented, with females experiencing more aggressive disease and different responses to treatment. While underlying mechanisms remain elusive, immune factors and lifestyle components, such as diet and physical activity, could play a role in shaping disease outcomes. Since Th cells are key drivers of RA, this study characterised CD4 Th subset frequencies, including Th1, Th2, Th17 and Th1/17 cells, in a cohort of males and females with established RA. Considering the role of diet and lifestyle in RA development, we also evaluated participant diet and lifestyle patterns. MethodsAn observational cross-sectional cohort study profiling 39 individuals (19 RA and 20 age and sex matched controls) with no major co-morbidities was conducted. Percentages of Th1, Th2, Th17 and Th1/17 cells from peripheral blood were determined by flow cytometry as well as serum levels of RF and cytokines IL17, IFN-{gamma}, TNF-, GM-CSF, TGF-{beta}, IL-6, and CRP by ELISA. Dietary intake was assessed by Food Frequency Questionnaire (FFQ), the Dietary inflammatory Index (DII) calculated from nutrient intake. Physical activity levels were evaluated by Global Physical Activity Questionnaire (GPAQ). ResultsSex-specific differences of Th17, Th1 an Th2 cells were observed in RA groups. Males had lower levels of Th1 cells and higher levels of Th17 cells than control subjects, while females had lower levels of Th2 cells than controls. Female RA subjects had higher ratio of Th1:Th2 cells than controls, while male RA subjects had higher Th17:Th1 ratio than controls. Interestingly, circulating CD4 Th subset levels were predictive of RA in this cohort. No changes in cytokine levels were observed. The male RA group consumed 30% less carbohydrate (RA = 156g +/-57g, Control = 253g +/-59g; p=0.003), 37% less sugar (RA = 74.1g +/-29g, Control = 118g +/-33g; p=0.004) and 30% less dietary fibre (R = 33g +/-8g, Control = 48g +/-13 g; p=0.008) than the male control group. The female RA group had the lowest consumption of alcohol in comparison to female control group (RA = 0.31g, Control = 8.97g; p=0.047). Male subjects had a 4x higher DII than females (p=0.012). ConclusionsOur findings highlight potential sex-specific differences in CD4+ Th cell subsets in individuals with established RA, indicating that sex may influence immune cell composition in this disease. Furthermore, dietary components showed sex-specific consumption patterns, underscoring the potential role of tailored lifestyle interventions in modulating immune responses in RA. Evaluating immunological sex differences and dietary and lifestyle factors may be important for enhancing management strategies in RA.

immunology↗

Adaptive immunity shapes innate and epithelial cell landscapes by silencing tonic IFN-gamma in innate lymphoid cells during homeostasis.

During homeostasis, innate and epithelial cells undergo continuous maturation, shaped by microbial, molecular and cellular interactions. While these cells influence adaptive immunity during steady-state conditions, the reciprocal homeostatic role of adaptive immune cells in the maturation and function of innate and epithelial cells remains underexplored. Here, through computational approaches and murine models, we establish that adaptive immunity shapes innate immune and epithelial homeostatic landscapes. Mechanistically, adaptive immunity acts as a brake on type 1 polarization and diversification of innate lymphocytes (ILCs). Without adaptive immunity, the innate cellular interactions within the mesenteric lymph nodes are dominated by an interferon-gamma (IFN{gamma}) signaling network. Moreover, the innate immune and epithelial cells follow distinct phenotypic and functional trajectories, including ILCs acquiring myeloid markers, monocytes adopting an inflammatory path, and colonic epithelial cells expressing altered antimicrobial peptides and losing Paneth-like features. Depleting ILCs, abolishing IFN{gamma} signaling, or restoring adaptive immunity reduces these IFN{gamma}-driven changes. Thus, our findings highlight a homeostatic function of adaptive immunity in modulating innate and epithelial cell communication, diversity, composition, function, and differentiation, notably by limiting ILC-derived IFN{gamma}.

immunology↗

MYC shapes ER-mitochondria calcium transfer by directly targeting ITPR1: implications for MYC-induced safeguard mechanisms and cancer

The MYC and NMYC transcription factors (TFs) play a key role in cell proliferation and are overexpressed in most cancer cells. However, in normal cells their overexpression triggers safeguard mechanisms promoting cell death and cellular senescence, which are bypassed in cancer cells. The mechanisms of action of this TF family are only partially understood. Here, we reveal that in normal cells MYC binds to the Inositol 1,4,5-Trisphosphate Receptor type 1 (ITPR1) gene and upregulates its expression, triggering an ER-mitochondria calcium (Ca2+) transfer, which is involved in MYC-induced cell death and senescence. Supporting a tumor suppressive role of MYC/ITPR1 axis, ITPR1 expression is generally decreased in cancer and reactivation of this pathway induces cancer cell death. Nevertheless, some cancer cells, generally expressing high levels of MYCN and/or MYC, also express high level of ITPR1, which correlates with high expression of BCL2, encoding an inhibitor of ITPR1. Strikingly, in high-risk MYCN-amplified neuroblastoma, ITPR1 expression is controlled by NMYC and its level correlates with worse patient survival. In these cells, blocking the interaction between BCL2 and ITPR1 induces mitochondrial Ca2+ accumulation and cell death, and decreases tumor size. Collectively these data highlight a new function of MYC factors by controlling Ca2+ signaling, which could constitute an unsuspected vulnerability for some cancer cells, including high-risk MYCN-amplified neuroblastoma cells.

cancer biology↗

Atypical contribution of caspase-3 to melanoma cancer cell motility by regulation of coronin 1B activity

Recent studies have unveiled unexpected connections between cell death and cell motility. While traditionally recognized for their pro-apoptotic roles, caspases have emerged as regulators of physiological processes beyond cell death, including cellular differentiation and motility. In some particularly aggressive cancers like melanoma, caspase-3, a prominent executioner caspase, is unexpectedly and inexplicably highly expressed. Here, we describe a novel non-apoptotic role for caspase-3 in melanoma cell motility. Through comprehensive molecular and cellular analyses, we demonstrate that caspase-3 is constitutively associated with the cytoskeleton and crucially regulates melanoma cell migration and invasion in vitro and in vivo. Mechanistically, caspase-3 interacts with and modulates the activity of coronin 1B, a key regulator of actin polymerization, thereby promoting melanoma cell motility, independently of its apoptotic protease function. Furthermore, we identify specificity protein 1 (SP1) as a transcriptional regulator of CASP3 expression, and show that its inhibition reduces caspase-3 expression and impairs melanoma cell migration. Overall, this study provides insights into the multifaceted roles of caspase-3 in cancer progression, highlighting its relevance as a novel target for anti-metastatic therapies.

cancer biology↗

Selective capture of circulating metastatic cancer cell clusters from lung cancer patients reveals a unique genomic profile that identifies anti-metastatic molecular therapeutic targets.

Metastasis remains the leading cause of cancer deaths worldwide and lung cancer, known for its highly metastatic progression, remains among the most lethal of malignancies. The heterogeneous genomic profile of lung cancer metastases is often unknown. Since different metastatic events can selectively spread to multiple organs, strongly suggests more studies are needed to understand and target these different pathways. Unfortunately, access to the primary driver of metastases, the metastatic cancer cell clusters (MCCCs), remains difficult and limited. These metastatic clusters have been shown to be 100-fold more tumorigenic than individual cancer cells. Capturing and characterizing MCCCs is a key limiting factor in efforts to help treat and ultimately prevent cancer metastasis. Elucidating differentially regulated biological pathways in MCCCs will help uncover new therapeutic drug targets to help combat cancer metastases. We demonstrate a novel, proof of principle technology, to capture MCCCs directly from patients whole blood. Our platform can be readily tuned for different solid tumor types by combining a biomimicry-based margination effect coupled with immunoaffinity to isolate MCCCs. Adopting a selective capture approach based on overexpressed CD44 in MCCCs provides a methodology that preferentially isolates them from whole blood. Furthermore, we demonstrate a high capture efficiency of more than 90% when spiking MCCC-like model cell clusters into whole blood. Characterization of the captured MCCCs from lung cancer patients by immunofluorescence staining and genomic analyses, suggests highly differential morphologies and genomic profiles., This study lays the foundation to identify potential drug targets thus unlocking a new area of anti-metastatic therapeutics.

cancer biology↗

Single molecule DNA methylation and hydroxymethylation reveal unique epigenetic identity profiles of T helper cells

Both identity and plasticity of CD4 T helper (Th) cells are regulated in part by epigenetic mechanisms. However, a method that reliably and readily profiles DNA base modifications is still needed to finely study Th cell differentiation. Cytosine methylation (5mC) and cytosine hydroxymethylation (5hmC) are DNA modifications that identify stable cell phenotypes but their potential to characterize intermediate cell transitions has not yet been evaluated. To assess transition states in Th cells, we developed a new method to profile Th cell identity using cas9-targeted single molecule nanopore sequencing and found that 5mC and 5hmC can be used as markers of cellular identity. Targeting as few as 10 selected genomic loci, we were able to distinguish major differentiated T cell subtypes as well as intermediate phenotypes by their native DNA 5mC/5hmC patterns. Moreover, by using off-target sequences we were able to infer transcription factor activities relevant to each cell subtype. Our analysis demonstrates the importance of epigenetic regulation by 5mC and 5hmC modifications in the establishment of Th cell identity. Furthermore, our data highlight the potential to exploit this immune profiling application to elucidate the pathogenic role of Th transition states in autoimmune diseases.

immunology↗

Gene signature of circulating platelet-bound neutrophils is associated with poor prognosis in cancer patients

Beyond their critical role in hemostasis, platelets physically interact with neutrophils to form neutrophil-platelet aggregates (NPAs), enhancing neutrophil effector functions during inflammation. NPAs may also promote disease worsening in various inflammatory diseases. However, characterization of NPAs in cancer remains totally unexplored. Using ImageStream(R)X (ISX) imaging flow cytometer, we were not only allowed able to detect CD15+ CD14- CD36+ ITGA2B+ NPAs in both healthy donors (HDs) and cancer patients bloods, but we also showed that NPAs result from the binding of platelets preferentially to low-density neutrophils (LDNs) as opposed to normal-density neutrophils (NDNs). By re-analyzing two independent public scRNAseq data of whole blood leukocytes from cancer patients and HDs, we could identify a subset of neutrophils with high platelet gene expression that may correspond to NPAs. Moreover, we showed that cancer patients derived NPAs possessed a distinct molecular signature compared with the other neutrophil subsets, independently of platelet genes. Gene ontology (GO) term enrichment analysis of this NPAs-associated neutrophil transcriptomic signature revealed a significant enrichment of neutrophil degranulation, chemotaxis and trans-endothelial migration GO terms. Lastly, using The Cancer Genome Atlas (TCGA), we could show by multivariate Cox analysis that the NPAs-associated neutrophil transcriptomic signature was associated with a worse patient prognosis in several cancer types. These results suggest that neutrophils from NPAs are systemically primed by platelets empowering them with cancer progression capacities once at tumor site. NPAs may therefore hold clinical utility as novel non-invasive blood prognostic biomarker in cancer patients with solid tumors. Novelty and ImpactPlatelets physically interact with peripheral blood neutrophils to form neutrophil-platelet aggregates (NPAs), known to promote disease worsening in various inflammatory diseases. However, characterization of NPAs in cancer remains totally unexplored. We showed that NPAs-associated neutrophils were a yet-unreported unique subset of circulating neutrophils associated with a worse patient prognosis in several cancer types. NPAs may hold clinical utility as novel non-invasive blood prognostic biomarker in cancer patients with solid tumors.

immunology↗

Confined migration promotes cancer metastasis through resistance to anoikis and increased invasiveness

Mechanical stress is known to fuel several hallmarks of cancer, ranging from genome instability to uncontrolled proliferation or invasion. Cancer cells are constantly challenged by mechanical stresses not only in the primary tumour but also during metastasis. However, this latter has seldom been studied with regards to mechanobiology, in particular resistance to anoikis, a cell death programme triggered by loss of cell adhesion. Here, we show in vitro that migrating breast cancer cells develop resistance to anoikis following their passage through microporous membranes mimicking confined migration (CM), a mechanical constriction that cancer cells encounter during metastasis. This CM-induced resistance was mediated by Inhibitory of Apoptosis Proteins (IAPs), and sensitivity to anoikis could be restored after their inhibition using SMAC mimetics. Anoikis-resistant mechanically-stressed cancer cells displayed enhanced cell motility and evasion from natural killer cell-mediated immune surveillance, as well as a marked advantage to form lung metastatic lesions in mice. Our findings reveal that CM increases the metastatic potential of breast cancer cells.

cancer biology↗

SMAD4 governs a feedforward regulation of the TGF-beta effects in CD8 T cells that contributes to preventing chronic intestinal inflammation

SMAD4, a key mediator of TGF-{beta} signaling, plays a crucial role in T cells to prevent chronic gut inflammation. However, the molecular mechanisms underlying this control remain elusive. Using different genetic and epigenetic approaches, we unexpectedly reveal that SMAD4 in CD8 T cells prevents chronic intestinal inflammation by a feedforward mechanism that is TGF-{beta}-independent. Prior to any TGF-{beta}-receptor engagement, SMAD4 acts as an active and basal repressor of epigenetic, transcriptional and functional TGF-{beta} imprinting in CD8 T cells. Thus, in sharp opposition to total TGF-{beta} signaling deletion, SMAD4 deletion impairs naive CD8 T cell effector predisposition but promotes CD8 T cell accumulation and epithelial retention by promoting their response to IL-7 and their expression of integrins such as Itgae. Besides, SMAD4 deletion unleashes the induction of a wide range of TGF-{beta}-signaling-repressors such as Smad7, Ski, Skil, and Smurf2 and hampers TGF-{beta}-mediated CD8 T cell immunosuppression. Mechanistically, prior to any TGF-{beta} signal, SMAD4 binds to the loci of several TGF-{beta}-target genes, and by regulating histone acetylation, represses their expression. The massive gut epithelial colonization, associated with their escape from the immunoregulatory TGF-{beta} effects overtakes their poor effector preconditioning and elicits microbiota-driven chronic epithelial CD8 T cell activation. Hence, in an anticipatory manner, independently of TGF-{beta}, SMAD4 governs a feedforward regulation of TGF-{beta} effects in CD8 T cells, preventing chronic intestinal inflammation.

immunology↗

Minimal detection and low biological fluctuation of mitochondrial CpG methylation at the single-molecule level

Cytosine DNA methylation in the CpG context (5mCpG) is associated with the transcriptional status of nuclear DNA. Due to technical limitations, it has been less clear if mitochondrial DNA (mtDNA) is methylated and whether 5mCpG has a regulatory role in this context. The main aim of this work was to develop and validate a novel tool for determining methylation of mtDNA and to corroborate its existence across different biological contexts. Using long-read nanopore sequencing we found low levels of CpG methylation (with few exceptions) and little variation across biological processes: differentiation, oxidative stress, and cancer. 5mCpG was overall higher in tissues compared to cell lines, with small additional variation between cell lines of different origin. Although we do show several significant changes in all these conditions, 5mCpG is unlikely to play a major role in defining the transcriptional status of mitochondrial genes.

genomics↗

Long read sequencing and de novo assembly of Hepatitis B Virus identifies 5mCpG in CpG islands

Hepatitis B Virus (HBV) is a 3.2KB DNA virus that causes acute and chronic hepatitis. HBV infection is a world health problem, with 350 million chronically infected people at increased risk of developing liver disease and hepatocellular carcinoma (HCC). Methylation of HBV DNA in a CpG context (5mCpG) can alter the expression patterns of viral genes related to infection and cellular transformation. Moreover, it may also provide clues to why certain infections are cleared, or persist with or without progression to cancer. The detection of 5mCpG often requires techniques that damage DNA or introduce bias through a myriad of limitations. Therefore, we developed a method for the detection of 5mCpG on the HBV genome that does not rely on bisulfite conversion or PCR. With cas9 guided RNPs to specifically target the HBV genome, we enriched in HBV DNA from Primary Human Hepatocytes (PHH) infected with different HBV genotypes, as well as enriching in HBV from infected patient liver tissue; followed by sequencing with Oxford Nanopore Technologies MinION. Detection of 5mCpG by Nanopore sequencing was benchmarked with Bisulfite-quantitative Methyl Specific PCR (BS-qMSP). 5mCpG levels in HBV determined by BS-qMSP and Nanopore sequencing were highly correlated. Our Nanopore sequencing approach achieved a coverage of [~]2000x of HBV depending on infection efficacy, sufficient coverage to perform a de novo assembly and detect small fluctuations in HBV methylation, providing the first de novo assembly of native HBV DNA, as well as the first landscape of 5mCpG from native HBV sequences. Moreover, by capturing entire HBV genomes, we explored the epigenetic heterogeneity of HBV in infected patients and identified 4 epigenetically distinct clusters based on methylation profiles. This method is a novel approach that enables the enrichment of viral DNA in a mixture of nucleic acid material from different species and will serve as a valuable tool for infectious disease monitoring.

genomics↗

Failed apoptosis enhances melanoma cancer cells aggressiveness

Triggering apoptosis remains an efficient strategy to treat cancer. However, apoptosis is no longer a final destination, since cells can undergo partial apoptosis without dying. Recent evidence shows that partial mitochondrial permeabilization and non-lethal caspase activation occur under certain circumstances, though it remains unclear how failed apoptosis impacts established cancers. Using a cancer cell model to trigger non-lethal caspase activation based on either BH3-only protein expression or chemotherapy treatment, we found that melanoma cancer cells failing to undergo complete apoptosis have a particular transcriptomic signature associated with focal adhesions, transendothelial migration and modifications of actin cytoskeleton. In line with this, cancer cells surviving apoptosis have a gain in migratory and invasive properties both in vitro (random migration, chemotaxis, wound healing and invasion assays) and in vivo (in a model of zebrafish metastasis) We further demonstrate that the failed apoptosis-associated gain in invasiveness is regulated by the c-Jun N-terminal kinase (JNK) pathway while its RNA seq signature is found in metastatic melanoma. These findings are highly significant for understanding how cell death can both cure and promote cancer.

cancer biology↗

Genome-wide 5-hydroxymethylcytosine (5hmC) emerges at early stage of in vitro hepatocyte differentiation

How cells reach different fates despite using the same DNA template, is a basic question linked to differential patterns of gene expression. Since 5-hydroxymethylcytosine (5hmC) emerged as an intermediate metabolite in active DNA demethylation, there have been increasing efforts to elucidate its function as a stable modification of the genome, including a role in establishing such tissue-specific patterns of expression. Recently we described TET1-mediated enrichment of 5hmC on the promoter region of the master regulator of hepatocyte identity, HNF4A, which precedes differentiation of liver adult progenitor cells in vitro. Here we asked whether 5hmC is involved in hepatocyte differentiation. We found a genome-wide increase of 5hmC as well as a reduction of 5-methylcytosine at early hepatocyte differentiation, a time when the liver transcript program is already established. Furthermore, we suggest that modifying s-adenosylmethionine (SAM) levels through an adenosine derivative could decrease 5hmC enrichment, triggering an impaired acquisition of hepatic identity markers. These results suggest that 5hmC is a regulator of differentiation as well as an imprint related with cell identity. Furthermore, 5hmC modulation could be a useful biomarker in conditions associated with cell de-differentiation such as liver malignancies.\n\nGraphical AbstractIt has been suggested that 5-hydroxymethylcytosine (5hmC) is an imprint of cell identity. Here we show that commitment to a hepatocyte transcriptional program is characterized by a demethylation process and emergence of 5hmC at multiple genomic locations. Cells exposed to an adenosine derivative during differentiation did not reach such 5hmC levels, and this was associated with a lower expression of hepatocyte-markers. These results suggest that 5hmC enrichment is an important step on the road to hepatocyte cell fate.\n\nO_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

genomics↗

The DNA Methylome of Inflammatory Bowel Disease (IBD) reflects intrinsic and extrinsic factors in intestinal epithelial cells

Abnormal DNA methylation has been described in human inflammatory conditions of the gastrointestinal tract, such as inflammatory bowel disease (IBD). As other complex diseases, IBD results from the balance between genetic predisposition and environmental exposures. As such, DNA methylation may be placed as an effector of both, genetic susceptibility variants and/or environmental signals such as cytokine exposure. We attempted to discern between these two non-excluding possibilities by performing a meta-analysis of DNA methylation data in intestinal epithelial cells of IBD and control samples. We identified abnormal DNA methylation at different levels: deviation from mean methylation signals at site and region levels, and differential variability. A fraction of such changes are associated with genetic polymorphisms linked to IBD susceptibility. In addition, by comparing with another intestinal inflammatory condition (i.e. celiac disease) we propose that aberrant DNA methylation can also be the result of unspecific processes such as chronic inflammation. Our characterization suggests that IBD methylomes combine intrinsic and extrinsic responses in intestinal epithelial cells, and could point to knowledge-based biomarkers of IBD detection and progression. Graphical AbstractConceptual representation of the study. Using a meta-analysis strategy we identified differentially methylated positions or regions (DMP/DMR) in IBD. Our assumption is that gene expression changes (IBD phenotype) take place downstream of DNA methylation. In turn, abnormal DNA methylation can be explained by a direct effect of inflammatory cytokines ("signaling") and/or the result of a genetic polymorphism (SNP). SNP-DMP associations are called methylation quantitative trait loci (mQTL). O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/565200v1_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@b9fc96org.highwire.dtl.DTLVardef@7619c5org.highwire.dtl.DTLVardef@1961352org.highwire.dtl.DTLVardef@1ce9d84_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

Interplay between the epigenetic enzyme lysine (K)-specific demethylase 2B and Epstein-Barr virus infection.

Histone modifier lysine (K)-specific demethylase 2B (KDM2B) plays a role in hematopoietic cells differentiation and its expression appears to be deregulated in certain cancers of hematological and lymphoid origins. We have previously found that KDM2B gene is differentially methylated in cell lines derived from the Epstein-Barr virus (EBV) associated endemic Burkitts lymphomas (eBL) compared to EBV negative sporadic BL cells. However, whether KDM2B plays a role in eBL development has never been previously demonstrated. Oncogenic viruses have been shown to hijack the host cell epigenome to complete their life cycle and to promote the transformation process by perturbing cell chromatin organization. Here we investigated whether EBV would alter KDM2B levels to enable its life cycle and promote B-cells transformation. We show that infection of B-cells with EBV leads to down-regulation of KDM2B levels. We also show that LMP1, one of the main EBV transforming proteins, induces increased DNMT1 recruitment to KDM2B gene and augments its methylation. By altering KDM2B levels and performing chromatin immunoprecipitation in EBV infected B-cells, we were able to show that KDM2B is recruited to the EBV gene promoters and inhibits their expression. Furthermore, forced KDM2B expression in immortalized B-cells led to altered mRNA levels of some differentiation-related genes. Our data show that EBV deregulates KDM2B levels through an epigenetic mechanism and provide evidence for a role of KDM2B in regulating virus and host cell gene expression, warranting further investigations to assess the role of KDM2B in the process of EBV-mediated lymphomagenesis.\n\nIMPORTANCE. In Africa, Epstein-Barr virus infection is associated with endemic Burkitt lymphoma, a pediatric cancer. The molecular events leading to its development are poorly understood compared to the sporadic Burkitt lymphoma. In a previous study, by analyzing the DNA methylation changes in endemic compared to sporadic Burkitt lymphomas cell lines, we identified several differential methylated genomic positions in proximity of genes with a potential role in cancer, among them the KDM2B gene. KDM2B encodes a histone H3 demethylase already shown to be involved in some hematological disorders. However, whether KDM2B plays a role in the development of Epstein-Barr virus-mediated lymphoma has never been investigated before. In this study we show that Epstein-Barr virus deregulates KDM2B expression and describe the underlying mechanisms. We also reveal a role of the demethylase in controlling viral and B-cells genes expression, thus highlighting a novel interaction between the virus and the cellular epigenome.

microbiology↗