Biology subjects

Amengual, J.

Publications and source records attributed to Amengual, J..

9 recordsLinked to original sources

bioRxiv2025

ZEB1 regulates BCL2 in cancer-associated fibroblasts to promote cholangiocarcinoma chemoresistance to gemcitabine and cisplatin

Intrahepatic cholangiocarcinoma (iCCA) is an agressive tumour from the biliary tree that is characterized by a prominent desmoplastic stroma mainly composed of cancer-associated fibroblasts (CAF) and a poor prognosis due to its late clinical presentation and the lack of effective non-surgical treatments. Current therapies still include chemotherapeutic combinations of gemcitabine and cisplatin for the majority of the patients showing poor results due the apparition of resistance. This situation led us to interrogate the potential role in the development of chemoresistance of ZEB1, an EMT-inducing transcription factor (EMT-TF) that we previously identified as a pro tumorigenic factor in tumour cells and CAF of iCCA. By analysing human CCA samples and sc-RNAseq public databases, we show here that ZEB1 is present in the tumour microenvironment of all iCCA patients tested and is prominently expressed by CAF. Using cellular models of CAF, we show that cells depleted for ZEB1 are more sensitive to gemcitabine and cisplatin, via a mechanism involving the regulation of the anti-apoptotic gene BCL2. Moreover, ZEB1 expressing CAF protect iCCA tumour cells against the toxicity of the chemotherapeutic drugs, an event that could be reversed by a BCL2 inhibitor venetoclax. Therefore, our results point to the use of BCL2 inhibitors to improve the efficacy of current chemotherapeutic regimens of gemcitabine and cisplatin in iCCA patients.

cancer biology↗

bioRxiv2025

Astrocytic Ceruloplasmin Deficiency Triggers Iron Toxicity and Neurodegeneration in a LRRK2 Parkinson's Tri-Culture Model

Astrocytes and microglia carrying the LRRK2-G2019S mutation contribute to non-cell- autonomous dopaminergic neuron (DAn) degeneration in Parkinsons disease (PD), but the mechanisms underlying their interplay remain unclear. Here, we developed a novel induced pluripotent stem cell (iPSC)-derived tri-culture system comprising healthy DAn and either LRRK2-mutant or isogenic control iPSC-derived astrocytes and microglia. Using integrated functional assays and transcriptomic profiling, we found that mutant astrocytes adopt a hyperreactive state, driving microglial activation and subsequent DAn degeneration. Mechanistically, we identified a selective downregulation of ceruloplasmin (CP), a copper-dependent ferroxidase, in mutant astrocytes, leading to disrupted iron homeostasis with accumulation of Fe2+ and ROS. This iron dysregulation mediated both microglial reactivity and neurodegeneration. Notably, pharmacological restoration of CP re-established iron homeostasis, reduced microglial activation, and protected DAn from degeneration. Our findings uncover a novel astrocyte-microglia-neuron axis driving PD pathogenesis and showcase the power of our unique stem cell tri-culture platform for dissecting disease mechanisms and discovering therapeutic targets.

cell biology↗

bioRxiv2024

Computation-aided Design of Rod-Shaped Janus Base Nanopieces for Improved Tissue Penetration and Therapeutics Delivery

Despite the development of various drug delivery technologies, there remains a significant need for vehicles that can improve targeting and biodistribution in "hard-to-penetrate" tissues. Some solid tumors, for example, are particularly challenging to penetrate due to their dense extracellular matrix (ECM). In this study, we have formulated a new family of rod-shaped delivery vehicles named Janus base nanopieces (Rod JBNps), which are more slender than conventional spherical nanoparticles, such as lipid nanoparticles (LNPs). These JBNp nanorods are formed by bundles of DNA-inspired Janus base nanotubes (JBNts) with intercalated delivery cargoes. To develop this novel family of delivery vehicles, we employed a computation-aided design (CAD) methodology that includes molecular dynamics and response surface methodology. This approach precisely and efficiently guides experimental designs. Using an ovarian cancer model, we demonstrated that JBNps markedly improve penetration into the dense ECM of solid tumors, leading to better treatment outcomes compared to FDA-approved spherical LNP delivery. This study not only successfully developed a rod-shaped delivery vehicle for improved tissue penetration but also established a CAD methodology to effectively guide material design.

bioengineering↗

bioRxiv2023

FITM2 deficiency results in ER lipid accumulation, ER stress, reduced apolipoprotein B lipidation, and VLDL triglyceride secretion in vitro and in mouse liver

Structured AbstractO_ST_ABSObjectivesC_ST_ABSTriglyceride (TG) association with apolipoprotein B100 (apoB100) serves to form very low density lipoproteins (VLDL) in the liver. The repertoire of factors that facilitate this association is incompletely defined. FITM2, an integral endoplasmic reticulum (ER) protein, was originally discovered as a factor participating in cytoplasmic lipid droplets (LDs) in tissues that do not form VLDL. We hypothesized that in the liver, in addition to promoting cytosolic LD formation, FITM2 would also transfer TG from its site of synthesis in the ER membrane to nascent VLDL particles within the ER lumen. MethodsExperiments were conducted using a rat hepatic cell line (McArdle-RH7777, or McA cells), an established model of mammalian lipoprotein metabolism, and mice. FITM2 expression was reduced using siRNA in cells and by liver specific cre-recombinase mediated deletion of the Fitm2 gene in mice. Effects of FITM2 deficiency on VLDL assembly and secretion in vitro and in vivo were measured by multiple methods, including density gradient ultracentrifugation, chromatography, mass spectrometry, simulated Raman spectroscopy (SRS) microscopy, sub-cellular fractionation, immunoprecipitation, immunofluorescence, and electron microscopy. Main findings1) FITM2-deficient hepatic cells in vitro and in vivo secrete TG-depleted VLDL particles, but the number of particles is unchanged compared to controls; 2) FITM2 deficiency in mice on a high fat diet (HFD) results in decreased plasma TG levels. The number of apoB100-containing lipoproteins remains similar, but shift from VLDL to LDL density; 3) Both in vitro and in vivo, when TG synthesis is stimulated and FITM2 is deficient, TG accumulates in the ER, and despite its availability this pool is unable to fully lipidate apoB100 particles; 4) FITM2 deficiency disrupts ER morphology and results in ER stress. Principal conclusionsThe results suggest that FITM2 contributes to VLDL lipidation, especially when newly synthesized hepatic TG is in abundance. In addition to its fundamental importance in VLDL assembly, the results also suggest that under dysmetabolic conditions, FITM2 may be a limiting factor that ultimately contributes to non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH).

biochemistry↗

bioRxiv2023

The hepatocyte Epidermal Growth Factor Receptor (EGFR) pathway regulates the cellular interactome within the liver fibrotic niche

Background & AimsLiver fibrosis is the consequence of chronic liver injury in the presence of an inflammatory component. Although the main executors of this activation are known, the mechanisms that lead to the inflammatory process that mediates the production of profibrotic factors are not well characterized. The Epidermal Growth Factor Receptor (EGFR) signaling in hepatocytes is essential for the regenerative process of the liver; however, its potential role in regulating the fibrotic niche is not yet clear. Approach & ResultsOur group generated a mouse model that expresses an inactive truncated form of the EGFR specifically in hepatocytes ({Delta}EGFR mice). Here, we have analyzed the response of WT and {Delta}EGFR mice to chronic treatment with CCl4. Resultsindicated that the hallmarks of liver fibrosis were attenuated in CCl4-treated {Delta}EGFR mice when compared to WT mice, coinciding with a faster resolution of the fibrotic process and an ameliorated damage. The absence of EGFR activity in hepatocytes induced changes in the pattern of immune cells in the liver, with a notable change in the population of M2 macrophages, more related to fibrosis resolution, as well as an increase in the population of lymphocytes related to eradication of the damage. Transcriptomic analysis of hepatocytes and secretome studies from extracellular media in in vitro studies allowed to elucidate the specific molecular mechanisms regulated by EGFR that mediate hepatocyte production of both pro-inflammatory and pro-fibrotic mediators. ConclusionsOur results support a pro-inflammatory and pro-fibrogenic role for the hepatocyte EGFR pathway during chronic liver damage.

pathology↗

bioRxiv2023

β-carotene accelerates resolution of atherosclerosis by promoting regulatory T cell expansion in the atherosclerotic lesion

{beta}-carotene oxygenase 1 (BCO1) catalyzes the cleavage of {beta}-carotene to form vitamin A. Besides its role in vision, vitamin A regulates the expression of genes involved in lipid metabolism and immune cell differentiation. BCO1 activity is associated with the reduction of plasma cholesterol in humans and mice, while dietary {beta}-carotene reduces hepatic lipid secretion and delays atherosclerosis progression in various experimental models. Here we show that {beta}-carotene also accelerates atherosclerosis resolution in two independent murine models, independently of changes in body weight gain or plasma lipid profile. Experiments in Bco1-/- mice implicate vitamin A production in the effects of {beta}-carotene on atherosclerosis resolution. To explore the direct implication of dietary {beta}-carotene on regulatory T cells (Tregs) differentiation, we utilized anti-CD25 monoclonal antibody infusions. Our data show that {beta}-carotene favors Treg expansion in the plaque, and that the partial inhibition of Tregs mitigates the effect of {beta}-carotene on atherosclerosis resolution. Our data highlight the potential of {beta}-carotene and BCO1 activity in the resolution of atherosclerotic cardiovascular disease.

immunology↗

bioRxiv2021

Distractibility and impulsivity neural states are distinct from attention states and modulate the implementation of attention

In the context of visual attention, it has been classically assumed that missing the response to a target or erroneously selecting a distractor occurs as a consequence of the (miss)allocation of attention in space. In the present paper, we challenge this view and provide evidence that, in addition to encoding spatial attention, prefrontal neurons also encode a distractibility-to-impulsivity state. Using supervised dimensionality reduction techniques, we identify two partially overlapped neuronal subpopulations associated either with attention or overt behaviour. The degree of overlap accounts for the behavioural gain associated with the good allocation of attention. We further describe the neural variability accounting for distractibility-to-impulsivity behaviour by a two dimensional state associated with optimality in task and responsiveness. Overall, we thus show that behavioural performance arises from the integration of task-specific neuronal processes and pre-existing neuronal states describing task-independent behavioural states, shedding new light on attention disorders such as ADHD.

neuroscience↗

bioRxiv2021

Attentional brain rhythms during prolonged cognitive activity

As routine and lower demand cognitive tasks are taken over by automated assistive systems, human operators are increasingly required to sustain cognitive demand over long periods of time. This has been reported to have long term adverse effects on cardiovascular and mental health. However, it remains unclear whether prolonged cognitive activity results in a monotonic decrease in the efficiency of the recruited brain processes, or whether the brain is able to sustain functions over time spans of one hour and more. Here, we show that during working sessions of one hour or more, contrary to the prediction of a monotonic decline, behavioral performance in both humans and non-human primates consistently fluctuates between periods of optimal and suboptimal performance at a very slow rhythm of circa 5 cycles per hour. These fluctuations are observed in both high attentional (in non-human primates) and low attentional (in humans) demand conditions. They coincide with fluctuations in pupil diameter, indicating underlying changes in arousal and information-processing load. Accordingly, we show that these rhythmic behavioral fluctuations correlate, at the neurophysiological level, with fluctuations in the informational attention orientation and perception processing capacity of prefrontal neuronal populations. We further identify specific markers of these fluctuations in LFP power, LFP coherence and spike-field coherence, pointing towards long-range rhythmic modulatory inputs to the prefrontal cortex rather than a local prefrontal origin. These results shed light on the resilience of brain mechanisms to sustained effort and have direct implications on how to optimize high cognitive demand working and learning environments.

neuroscience↗

bioRxiv2019

Integrating When and What Information in the Left Parietal Lobe Allows Language Rule Generalization

A crucial aspect when learning a language is discovering the rules that govern how words are combined in order to convey meanings. Since rules are characterized by sequential co-occurrences between elements (e.g. These cupcakes are unbelievable), tracking the statistical relationships between these elements is fundamental. However, statistical learning alone cannot fully account for the ability to create abstract rule representations that can be generalized, a paramount requirement of linguistic rules. Here, we provide evidence that, after the statistical relations between words have been extracted, the engagement of goal-directed attention is key to enable rule generalization. Incidental learning performance during a rule-learning task on an artificial language revealed a progressive shift from statistical learning to goal-directed attention. In addition, and consistent with the recruitment of attention, fMRI analyses of late learning stages showed left parietal activity within a broad bilateral dorsal fronto-parietal network. Critically, rTMS on participants peak of activation within the left parietal cortex impaired their ability to generalize learned rules to a structurally analogous new language. No stimulation or rTMS on a non-relevant brain region did not have the same interfering effect on generalization. Performance on an additional attentional task showed that rTMS on the same parietal site hindered participants ability to integrate what (stimulus identity) and when (stimulus timing) information about an expected target. The present findings suggest that learning rules from speech is a two-stage process: following statistical learning, goal-directed attention -involving left parietal regions- integrates what and when stimulus information to facilitate rapid rule generalization.

neuroscience↗