Biology subjects

Guillen, Y.

Publications and source records attributed to Guillen, Y..

9 recordsLinked to original sources

bioRxiv2023

IKK1 kinase coordinates BRD4 and JAK/STAT signaling to subvert DNA damage-based anticancer therapy

Activation of the IKK kinase complex has recurrently been linked to colorectal cancer (CRC) initiation and progression. However, identification of downstream effectors other than NF-{kappa}B has remained elusive. Analysis of IKK-dependent substrates after UV-treatment revealed that BRD4 phosphorylation by IKK is required for chromatin-binding dynamics upon damage. Moreover, IKK induces the NF-{kappa}B-dependent transcription of LIF leading to STAT3 activation, association of BRD4 to STAT3 and recruitment to specific target genes. IKK abrogation results in defective BRD4 and STAT3 function leading to irreparable DNA damage and apoptotic cell death upon different stimuli. Simultaneous inhibition of BRAF-dependent IKK activity or BRD4 and the JAK/STAT pathway enhanced the therapeutic potential of 5-FU plus irinotecan in CRC cells, and is curative in a chemotherapy-resistant CRC xenograft model. Coordinated expression of LIF and IKK is a poor prognosis marker for CRC patients. Our data uncover a functional link between IKK, BRD4 and JAK/STAT signaling with clinical relevance.

cancer biology↗

bioRxiv2023

Radical fringe facilitates NOTCH1 and JAG1 cis interactions to sustain Hematopoietic stem cell fate

Hematopoietic stem cells (HSCs) develop within a short time window from the hemogenic endothelium in the aorta- gonads-and mesonephros (AGM) region during embryonic development. The first HSCs reside within Intra-aortic hematopoietic clusters (IAHC) along with hematopoietic progenitors (HPC). The signalling mechanisms that divert HSCs from HPCs are unknown. Notch signaling is essential for arterial specification, IAHC formation and HSC activity, but current studies on how Notch drives these different fates are inconsistent. To determine the role of Notch in the specification of hemogenic endothelium, HSC and/or HPCs, we extensively analyzed Notch dynamics in the period of HSC generation. We defined the expression pattern of Notch signalling molecules at the gene and protein level and established a molecular mechanism that reconcile previous studies demonstrating the loss of HSC activity in NOTCH1, JAG1 and RBPJ null mutants, the enhanced HSC generation by blocking specific Notch activities or the abrogation of emerging HSCs by high Notch activation. We now demonstrate that Notch activity is highest in a subset of Gfi1+ hemogenic endothelial cells and is gradually lost with HSC maturation. We uncover that the HSC phenotype is maintained through loss of Notch activity due to increasing levels of NOTCH1 and JAG1 interactions on the surface of the same cell (cis) that renders the NOTCH1 receptor from being activated. Forcing activation of the NOTCH1 receptor in IAHC cells activates a hematopoietic differentiation program and supports a cis-inhibitory function for JAG1 and NOTCH1. Furthermore, we demonstrate that this cis-inhibitory interaction is enabled by RADICAL FRINGE (RFNG), a glycosyltransferase that enhances the affinity of NOTCH1 to JAG1 in cis. Finally, our results indicate that NOTCH1-JAG1 cis-inhibition is necessary for preserving the HSC phenotype in the hematopoietic clusters of the aorta.

developmental biology↗

bioRxiv2022

IκBα controls dormancy induction in Hematopoietic stem cell development via retinoic acid

Recent findings are challenging the classical hematopoietic model in which long-term hematopoietic stem cells (LT-HSC) are the base of the hematopoietic system. Clonal dynamics analysis of the hematopoietic system indicate that LT-HSC are not the main contributors of normal hemapoiesis in physiological conditions and the hematopoietic system is mainly maintained by multipotent progenitors (MPPs, hereafter HPC) and LT-HSCs are mostly in a non-active state. The first HSCs emerge from the aorta-gonad and mesonephros (AGM) region along with hematopoietic progenitors (HPC) within hematopoietic clusters. Molecular pathways that determine the HSC fate instead of HPC are still unknown, although inflammatory signaling, including NF-{kappa}B has been implicated in the development of HSCs. Here, we identify a chromatin binding function for I{kappa}B (also known as the inhibitor of NF-{kappa}B) that is Polycomb repression complex 2 (PRC2)-dependent and specifically determines dormant vs proliferating HSCs from the onset of their emergence in the AGM. We find a specific reduction of LT-HSCs in the I{kappa}B knockout new-born pups. This defect is manifested at the FL stage already, and traceable to the first emerging HSCs in the E11.5 AGM, without affecting the general HPC population. I{kappa}B deficient LT-HSCs express dormancy signature genes, are less proliferative and can robustly respond to activation stimuli such as in vitro culture and serial transplantation. At the molecular level, we find decreased PRC2-dependent H3K27me3 at the promoters of several retinoic acid signaling elements in the I{kappa}B - deficient aortic endothelium and E14.5 FL LT-HSCs. Additionally, I{kappa}B binding itself is found in the promoters of retinoic acid receptors rar in the AGM, and rar{gamma} in the LT-HSC of FL. Overall, we demonstrate that the retinoic acid pathway is over-activated in the hematopoietic clusters of I{kappa}B-deficient AGMs leading to premature dormancy of LT-HSCs that persists in the FL LT-HSCs.

cell biology↗

bioRxiv2022

β-catenin activity induces an RNA biosynthesis program promoting therapy resistance in T Acute Lymphoblastic Leukemia

Understanding the molecular mechanisms that contribute to the appearance of chemotherapy resistant cell populations is necessary to improve cancer treatment. We have now investigated the role of {beta}-catenin/CTNNB1 in the evolution of T-Acute Lymphoblastic Leukemia (T-ALL) patients and its involvement in therapy resistance. We have identified a specific gene signature that is directly regulated by {beta}-catenin, TCF/LEF factors and ZBTB33/Kaiso in T-ALL cell lines, which is highly and significantly represented in 5 out of 6 refractory patients from a cohort of 40 children with T-ALL. By subsequent refinement of this gene signature, we found that a subset of {beta}-catenin target genes involved with RNA-processing function are sufficient to segregate T-ALL refractory patients in three independent cohorts. We demonstrate the implication of {beta}-catenin in RNA and protein synthesis in T-ALL and provide experimental evidence that {beta}-catenin is crucial for the cellular response to chemotherapy, mainly in the cellular recovery phase after treatment. We propose that combination treatments involving chemotherapy plus {beta}-catenin inhibitors will enhance chemotherapy response and prevent disease relapse in T-ALL patients.

cancer biology↗

bioRxiv2021

Gut Microbiome Signatures Linked to HIV-1 Reservoir Size and Viremia Control

BackgroundThe potential role of the gut microbiome as a predictor of immune-mediated HIV-1 control in the absence of antiretroviral therapy (ART) is still unknown. In the BCN02 clinical trial, which combined the MVA.HIVconsv immunogen with the latency-reversing agent romidepsin in early-ART treated HIV-1 infected individuals, 23% (3/13) of participants showed sustained low-levels of plasma viremia during 32 weeks of a monitored ART pause (MAP). Here, we present a multi-omics analysis to identify compositional and functional gut microbiome patterns associated with HIV-1 control in the BCN02 trial. ResultsViremic controllers during the MAP (controllers) exhibited higher Bacteroidales/Clostridiales ratio and lower microbial gene richness before vaccination and throughout the study intervention when compared to non-controllers. Longitudinal assessment indicated that the gut microbiome of controllers was enriched in pro-inflammatory bacteria and depleted in butyrate-producing bacteria and methanogenic archaea. Functional profiling also showed that metabolic pathways, including methanogenesis and carbohydrate biosynthesis, were significantly decreased in controllers. Fecal metaproteome analyses confirmed that baseline functional differences were mainly driven by Clostridiales. Participants with high baseline Bacteroidales/Clostridiales ratio had increased pre-existing immune activation-related transcripts. The Bacteroidales/Clostridiales ratio as well as host immune-activation signatures inversely correlated with HIV-1 reservoir size. ConclusionsThis proof-of-concept study suggests the Bacteroidales/Clostridiales ratio as a novel gut microbiome signature associated with HIV-1 reservoir size and immune-mediated viral control after ART interruption.

immunology↗

bioRxiv2021

Chemotherapy induces a YAP1-dependent fetal conversion to human Colorectal Cancer cells that is predictive of poor patient outcome

Current therapy against colorectal cancer is based on DNA-damaging agents that eradicate highly proliferative malignant cells. Whether sublethal chemotherapy affects tumor cell behavior and impacts on patient outcome is primarily unstudied. We now show that sublethal chemotherapy imposes a quiescent-like state to p53 wildtype human colorectal cancer (CRC) cells that is linked to the acquisition of a fetal phenotype downstream of YAP1, similar to that observed after intestinal damage. CRC cells displaying this fetal phenotype exhibit tumor- initiating activity comparable to untreated cells but superior metastatic capacity. Notably, nuclear YAP1 accumulation, or detection of the fetal signature in tumors predict poor prognosis in CRC patients carrying p53 wildtype tumors. Collectively, our results uncover a potential adverse response of tumor cells to suboptimal chemotherapy, and identify nuclear YAP1 and fetal conversion of colorectal tumors as biomarkers for prognosis and therapy prescription. Statement of significanceChemotherapy induces a quiescent-like phenotype to colorectal cancer cells that is linked to the acquisition of a YAP1-dependent fetal signature. Notably, this signature is predictive of patient outcome in different cohorts of human colorectal cancer.

cancer biology↗

bioRxiv2021

Dynamic association of IκBα to chromatin is regulated by acetylation and cleavage of histone H4

I{kappa}Bs exert a principal function as cytoplasmic inhibitors of the NF-kB transcription factors. Additional functions for I{kappa}B homologues have been described including association to chromatin and transcriptional regulatioin. Phosphorylated and SUMOylated I{kappa}B (pS-I{kappa}B) binds histones H2A and H4 in the stem and progenitor compartment of skin and intestine, but the mechanisms controlling its recruitment to chromatin are largely unstudied. We here show that serine 32-36 phosphorylation of I{kappa}B favors its binding with nucleosomes and demonstrated that p-I{kappa}B association to H4 is favored by acetylation at specific H4 lysine residues. N-terminal tail of H4 is lost during intestinal cell differentiation by proteolytic cleavage at residues 17-19 imposed ny trypsin or chymotrypsin, which interferes p-I{kappa}B binding. Paradoxically, inhibition of trypsin and chymotrypsin activity in HT29 cells increased p-I{kappa}B chromatin binding and impaired goblet cell differentiation, comparable to I{kappa}B deletion. Together our results indicate that dynamic binding of I{kappa}B to chromatin is a requirement for intestinal cell differentiation and provide a molecular base for the restricted nuclear distribution of p-I{kappa}B at specific stem cell compartments.

molecular biology↗

bioRxiv2020

Ancestral function of Inhibitors-of-kappaB regulates Caenorhabditis elegans development

Mammalian I{kappa}B proteins (I{kappa}Bs) exert their main function as negative regulators of NF-{kappa}B, a central signaling pathway controlling immunity and inflammation. An alternative chromatin role for I{kappa}Bs has been shown to affect stemness and cell differentiation. However, the involvement of NF-{kappa}B in this function has not been excluded. NFKI-1 and IKB-1 are I{kappa}B homologs in Caenorhabditis elegans, which lacks NF-{kappa}B nuclear effectors. We found that nfki-1 and ikb-1 mutants display developmental defects that phenocopy mutations in Polycomb and UTX-1 histone demethylase, suggesting a role for C. elegans I{kappa}Bs in chromatin regulation. Further supporting this possibility (i) we detected NFKI-1 in the nucleus of cells; (ii) NFKI-1 and IKB-1 bind to histones and Polycomb proteins, (iii) and associate with chromatin in vivo, and (iv) mutations in nfki-1 and ikb-1 alter chromatin marks. Based on these results, we propose that ancestral I{kappa}B inhibitors modulate Polycomb activity at specific gene subsets with an impact on development.

developmental biology↗

bioRxiv2018

Host genetic associations with the gut microbiota in HIV-1-infected subjects: a pilot exploratory study

The impact of host genetics on gut microbial dynamics is debated. No study to date has investigated the possible role of host genetics in shaping the gut microbiota in HIV-1 infected subjects. With the aim of generating preliminary data to inform future host genetic studies, we performed an exploratory host exome analysis of 147 subjects either infected or at risk of becoming infected with HIV-1 from the MetaHIV cohort in Barcelona. Using a DNA microarray chip, we sought to identify host genetic variants associated to three specific microbial features with a potentially inheritable component, and which were previously found to be associated with gut dysbiosis in HIV infection, i.e.: gut enterotype, presence of methanogenic archaea and microbial gene richness. After correction for multiple comparisons, we did not observe any statistically significant association between the hosts genetic landscape and the explored gut microbiome traits. These findings will help design future, adequately-powered studies to assess the influence of host genetics in the microbiome of HIV-1-infected subjects.

genomics↗