Biology subjects

Iovanna, J. L.

Publications and source records attributed to Iovanna, J. L..

7 recordsLinked to original sources

bioRxiv2024

EHMT2 Inactivation in Pancreatic Epithelial Cells Shapes the Transcriptional Landscape and Inflammation Response of the Whole Pancreas

The Euchromatic Histone Methyl Transferase Protein 2 (EHMT2), also known as G9a, deposits transcriptionally repressive chromatin marks that play pivotal roles in the maturation and homeostasis of multiple organs. Recently, we have shown that EHMT2 inactivation alters growth and immune gene expression networks, antagonizing KRAS-mediated pancreatic cancer initiation and promotion. Here, we elucidate the essential role of EHMT2 in maintaining a transcriptional landscape that protects organs from inflammation. Comparative RNA-seq studies between normal postnatal and young adult pancreatic tissue from EHMT2 conditional knockout animals (EHMT2fl/fl) targeted to the exocrine pancreatic epithelial cells (Pdx1-Cre and P48Cre/+), reveal alterations in gene expression networks in the whole organ related to injury-inflammation-repair, suggesting an increased predisposition to damage. Thus, we induced an inflammation repair response in the EHMT2fl/flpancreas and used a data science-based approach to integrate RNA-seq-derived pathways and networks, deconvolution digital cytology, and spatial transcriptomics. We also analyzed the tissue response to damage at the morphological, biochemical, and molecular pathology levels. The EHMT2fl/fl pancreas displays an enhanced injury-inflammation-repair response, offering insights into fundamental molecular and cellular mechanisms involved in this process. More importantly, these data show that conditional EHMT2 inactivation in exocrine cells reprograms the local environment to recruit mesenchymal and immunological cells needed to mount an increased inflammatory response. Mechanistically, this response is an enhanced injury-inflammation-repair reaction with a small contribution of specific EHMT2-regulated transcripts. Thus, this new knowledge extends the mechanisms underlying the role of the EHMT2-mediated pathway in suppressing pancreatic cancer initiation and modulating inflammatory pancreatic diseases.

cancer biology↗

bioRxiv2023

Spatially-resolved metabolomic identifies colibactin-specific principles of reprogrammed lipid metabolism to promote cancer progression.

Intratumoral bacteria locally contribute to cellular and molecular tumor heterogeneity that support cancer stemness through poorly understood mechanisms. This study aims to explore how Colibactin-producing Escherichia coli (CoPEC) flexibly alters the tumor microenvironment in right-sided colorectal cancer (CRC). Metabolomic and transcriptomic spatial profiling uncovered that CoPEC colonization establishes a high-glycerophospholipid microenvironment within the tumor that is conducive to exhaustion of infiltrated CD8+ T cell and has a lowered prognostic value in right-sided CRC. Mechanistically, the accumulation of lipid droplets in infected cancer cells relied on the production of colibactin as a measure to limit genotoxic stress and supply with sufficient energy for sustaining cell survival and lowering tumor immunogenicity. Specifically, a heightened phosphatidylcholine remodeling of CoPEC-infected cancer cells by the enzyme of the Lands cycle coincided with a lowered accumulation of proapoptotic ceramide and lysophosphatidylcholine. Consequently, a reduced infiltration of CD8+ T lymphocytes that produce the cytotoxic cytokines IFN-{gamma} was found where invading bacteria have been geolocated. By contrast, such an immunosuppressive dysmetabolic process was not observed when human colon cancer cells were infected with the mutant strain that did not produce colibactin (11G5{delta}ClbQ). This work revealed an unexpected property of CoPEC on lipid overload within tumors that could locally provide an inflammatory environment leading to immunosuppressive mechanisms and tumor expansion. This may pave the way for improving chemoresistance and subsequently outcome of CRC patients who are colonized by CoPEC.

cancer biology↗

bioRxiv2020

NUPR1 protects liver from lipotoxic injury by improving the endoplasmic reticulum stress response

Background and AimsNon-alcoholic fatty liver disease and related hepatic syndromes affect up to one third of the adult population. The molecular mechanisms underlying NAFL etiology remain elusive. Nuclear Protein 1 (NUPR1) expression increases upon cell injury in all organs and recently we report its active participation in the activation of the Unfolded Protein Response (UPR). The UPR typically maintains protein homeostasis, but downstream mediators of the pathway regulate metabolic functions, including lipid metabolism. NUPR1 and UPR increase have been reported in obesity and liver pathologies and the goal of this study was to investigate the roles of NUPR1 in this context. MethodsWe used patient-derived liver biopsies and in vitro and in vivo NUPR1 loss of functions models. First, we analysed NUPR1 expression in a cohort of morbidly obese patients (MOPs), with either simple fatty liver (NAFL) or more severe steatohepatitis (NASH). Next, we explored the metabolic roles of NUPR1 in wild type (Nupr1+/+) or Nupr1 knockout mice (Nupr1-/-) fed ad libitum with a high fat diet (HFD) for up to 15 weeks. ResultsNUPR1 expression is inversely correlated to hepatic steatosis progression. We found that NUPR1 participates in the activation of PPAR- signalling via UPR. PPAR- signalling, is involved in the maintenance of fat metabolism and proper lipid homeostasis and energy balance. As PPAR- signalling is controlled by UPR, collectively, these findings suggest a novel function for NUPR1 in protecting liver from metabolic distress by controlling lipid homeostasis, possibly through the UPR. ObjectiveNon-alcoholic fatty liver (NAFL) disease and related hepatic syndromes affect up to one third of the adult population in industrialised and developing countries. However, the molecular mechanisms underlying NAFL etiology remain elusive. Nuclear Protein 1 (NUPR1) expression increases upon cell injury in all organs including the liver. Recently, we report NUPR1 actively participates in activation of the Unfolded Protein Response (UPR). The UPR typically maintains protein homeostasis, but downstream mediators of the pathway regulate metabolic functions, including lipid metabolism. NUPR1 and UPR increase have been reported in obesity and liver pathologies and the goal of this study was to investigate the roles of NUPR1 in this context. DesignWe used patient-derived liver biopsies and in vitro and in vivo NUPR1 loss of functions models. First, we analysed NUPR1 expression in a cohort of morbidly obese patients (MOPs), with either simple fatty liver (NAFL) or more severe steatohepatitis (NASH). Next, we explored the metabolic roles of NUPR1 in wild type (Nupr1+/+) or Nupr1 knockout mice (Nupr1-/-) fed ad libitum with a high fat diet (HFD) for up to 15 weeks. ResultsNUPR1 expression is inversely correlated to hepatic steatosis progression. Mechanistically, we found NUPR1 participates in the activation of PPAR- signalling via UPR. PPAR- signalling, is involved in the maintenance of fat metabolism and proper lipid homeostasis and energy balance. As PPAR- signalling is controlled by UPR, collectively, these findings suggest a novel function for NUPR1 in protecting liver from metabolic distress by controlling lipid homeostasis, possibly through the UPR. ConclusionsAs PPAR- signalling is controlled by UPR, collectively, these findings suggest a novel function for NUPR1 in protecting liver from metabolic distress by controlling lipid homeostasis, possibly through the UPR. Lay summaryNUPR1 is activated during high caloric intake in both mice and patients. Decrease in expression or inhibition of NUPR1 worsens lipid deposition and hepatic damage. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=192 SRC="FIGDIR/small/350652v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@1d370c0org.highwire.dtl.DTLVardef@8f8dc9org.highwire.dtl.DTLVardef@a5aa49org.highwire.dtl.DTLVardef@4eb585_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LINUPR1 protects liver from high caloric intake hepatic damage C_LIO_LIThe function of NUPR1 in this context is to control the lipid homeostasis through the UPR and more specifically through PPAR- signalling. C_LIO_LINUPR1 could be used as a predictive marker for the gravity of NAFL progression. Moreover, as clinical interest is being raised around NUPR1 inhibitors to treat liver and pancreatic cancer, care should be taken in monitoring lipotoxic parameters. C_LI

cell biology↗

bioRxiv2020

Establishment of a pancreatic adenocarcinoma molecular gradient (PAMG) that predicts the clinical outcome of pancreatic cancer

BACKGROUNDA significant gap in pancreatic ductal adenocarcinoma (PDAC) patients care is the lack of molecular parameters characterizing tumors and allowing a personalized treatment. The goal of this study was to examine whole PDAC transcriptomic profiles to define a signature that would predict aggressiveness and treatment responsiveness better than done until now. METHODS AND PATIENTSTumors were obtained from 76 consecutive resectable (n=40) or unresectable (n=36) tumors. PDAC were transplanted in mice to produce patient-drived xenografts (PDX). PDX were classified according to their histology into five groups, from highly undifferentiated to well differentiated. This classification resulted strongly associated with tumors aggressiveness. A PDAC molecular gradient (PAMG) was constructed from PDX transcriptomes recapitulating the five histological groups along a continuous gradient. The prognostic and predictive value for PMAG was evaluated in: i/ two independent series (n=598) of resected tumors; ii/ 60 advanced tumors obtained by diagnostic EUS-guided biopsy needle flushing and iii/ on 28 biopsies from mFOLFIRINOX treated metastatic tumors. RESULTSA unique transcriptomic signature (PAGM) was generated with significant and independent prognostic value. PAMG significantly improves the characterization of PDAC heterogeneity compared to non-overlapping classifications as validated in 4 independent series of tumors (e.g. 308 consecutive resected PDAC, HR=0.321 95% CI [0.207;0.5] and 60 locally-advanced or metastatic PDAC, HR=0.308 95% CI [0.113;0.836]). The PAMG signature is also associated with progression under mFOLFIRINOX treatment (Pearson correlation to tumor response: -0.67, p-value < 0.001). CONCLUSIONWe identified a transcriptomic signature (PAMG) that, unlike all other stratification schemas already proposed, classifies PDAC along a continuous gradient. It can be performed on formalin-fixed paraffin-embedded samples and EUS-guided biopsies showing a strong prognostic value and predicting mFOLFIRINOX responsiveness. We think that PAMG could unify all PDAC preexisting classifications inducing a shift in the actual paradigm of binary classifications towards a better characterization in a gradient. Trial RegistrationThe PaCaOmics study is registered at www.clinicaltrials.gov with registration number NCT01692873. The validation BACAP study is registered at www.clinicaltrials.gov with registration number NCT02818829.

cancer biology↗

bioRxiv2020

The stress-induced protein NUPR1 orchestrates protein translation during ER-stress by interacting with eIF2-a

NUPR1 is a stress response protein overexpressed upon cell injury in virtually all organs including the exocrine pancreas. Despite NUPR1s well established role in the response to cell stress, the molecular and structural machineries triggered by NUPR1 activation remain largely unknown. In this study, we uncover an important role for NUPR1 in participating in the unfolded protein response pathway and the endoplasmic reticulum stress response. Biochemical results, confirmed by ultrastructural morphological observation, revealed alterations in the UPR in acinar cells of germline-deleted NUPR1 murine models, consistent with the inability to restore general protein translation. Bioinformatical analysis of NUPR1 interacting partners showed significant enrichment in translation initiation factors, including eukaryotic initiation factor (eIF) 2. Co-immunoprecipitation and proximity ligation assays both confirmed interaction between NUPR1 and eIF2 and its phosphorylated form (p-eIF2). Our. Moreover, our data also suggest loss of NUPR1 in cells results in maintained eIF2 phosphorylation and evaluation of nascent proteins by (peIF2), and click chemistry revealed that NUPR1-depleted PANC-1 cells displayed a slower post stress protein translational recovery compared to wild-type. Combined, this data proposes a novel role for NUPR1 in the integrated stress response pathway, at least partially through promoting efficient PERK-branch activity and resolution through a unique interaction with eIF2. SignificanceIn the pancreas, NUPR1 is required for a resolution of the ER stress response. During ER stress response, NUPR1 binds both eIF2 allowing for its dephosphorylation and restoration of new protein synthesis. HighlightsBiochemical analysis revealed a general reduction in the protein expression of downstream mediators of the unfolded protein response in the pancreas of mice lacking Nupr1. This finding suggests a novel role for NUPR1 in the UPR/ER stress response. Ultrastructural analysis of pancreata revealed reduced morphological alterations in tunicamycin-treated Nupr1-/- mice compared to Nupr1+/+ mice consistent with a maintained block in general protein translation. Co-immunoprecipitation of tagged NUPR1 confirmed a novel interaction with eIF2. Depletion of NUPR1 prolonged phosphorylation of eIF2, suggesting it may be involved in attenuation of the PERK branch of the UPR. NUPR1-depleted PANC-1 cells displayed a slower recovery of protein translation following UPR activation

cell biology↗

bioRxiv2020

Basal-like and Classical cells coexistence in pancreatic cancer revealed by single cell analysis

Pancreatic ductal adenocarcinoma (PDAC) is composed of stromal, immune and epithelial cells. Transcriptomic analysis of the epithelial compartment allows a binary classification into mainly two phenotypic subtypes, classical and basal-like. However, little is known about the intra-tumor heterogeneity of the epithelial component. Growing evidences suggest that this two side phenotypic segregation is not so clear and that both could coexist in a single tumor. In order to elucidate this hypothesis, we performed single-cell transcriptomic analyses using combinational barcoding on epithelial cells from 6 different classical PDAC obtained by Endoscopic Ultrasound (EUS) with Fine Needle Aspiration (FNA). In order to purify the epithelial compartment, PDAC were grown as Biopsy Derived Pancreatic Cancer Organoids. Single cell transcriptomic analysis allowed the identification of 4 main cell clusters present in different proportions in all tumors. Remarkably, although these tumors were classified as Classical, one of the clusters corresponded to a basal-like. These results depict the unanticipated high heterogeneity of pancreatic cancers and demonstrated that basal-like cells with a high aggressive phenotype are more widespread than expected.

cancer biology↗

bioRxiv2018

Inactivation of NUPR1 promotes cell death by coupling ER-stress responses with necrosis

Genetic inhibition of NUPR1 induces tumor growth arrest. Inactivation of NUPR1 expression in pancreatic cancer cells results in lower ATP production, higher consumption of glucose with a significant switch from OXPHOS to glycolysis followed by necrotic cell death. Importantly, induction of necrosis is independent of the caspase activity. We demonstrated that NUPR1 inactivation triggers a massive release of Ca2+ from the endoplasmic reticulum (ER) to the cytosol and a strong increase in ROS production by mitochondria with a concomitant relocalization of mitochondria to the vicinity of the ER. In addition, transcriptomic analysis of NUPR1-deficient cells shows the induction of an ER stress which is associated to a decrease in the expression of some ER stress response-associated genes. Indeed, during ER stress induced by the treatment with thapsigargin, brefeldin A or tunicamycin, an increase in the mitochondrial malfunction with higher induction of necrosis was observed in NUPR1-defficent cells. Finally, activation of NUPR1 during acute pancreatitis protects acinar cells of necrosis in mice. Altogether, these data enable us to describe a model in which inactivation of NUPR1 in pancreatic cancer cells results in an ER stress that induces a mitochondrial malfunction, a deficient ATP production and, as consequence, the cell death by necrosis.\n\nHighlightsNUPR1 expression promotes pancreatic cancer development and progression\n\nNUPR1-depletion is a promising therapeutic strategy to be used for treating cancers\n\nNUPR1-depletion induces ER stress, mitochondrial malfunction and a significant switch from OXPHOS to glycolysis followed by necrotic cell death\n\nInactivation of NUPR1 antagonizes cell growth by coupling a defective ER-stress response and a caspase-independent necrosis.

cell biology↗