Biology subjects

Espinosa, J. M.

Publications and source records attributed to Espinosa, J. M..

At least 19 recordsLinked to original sources

bioRxiv2026

A Trisomy 21 Model Atlas reveals conserved dosage effects and context-specific transcriptional responses across mouse and human models of Down syndrome

Trisomy 21, the genetic basis of Down syndrome, causes widespread transcriptional dysregulation with tissue-specific phenotypic consequences, but how this propagates across tissues, developmental stages, and model systems remains incompletely understood. We present the initial release of the Trisomy 21 Model Atlas, comprising bulk transcriptomic profiling and histopathology across seven tissues and three developmental timepoints in the Dp(16)1Yey mouse model along with transcriptional profiles from human iPSC-derived cell types. Triplicated genes show consistent, largely dosage-proportional increases in expression across tissues, developmental stages, sexes, and species. Nontriplicated genes, which account for the substantial majority of differential expression, are instead highly context-specific. Inflammatory and interferon-related gene sets are broadly enriched yet composed of distinct genes in each context, and integration with histopathology links expression signatures to tissue-specific pathological features. The Atlas is openly accessible and designed for expansion, providing a framework for interpreting conserved and context-specific consequences of chromosome 21 gene dosage.

genomics↗

bioRxiv2026

Altered follicular immunity in secondary lymphoid organs is associated with interferon hyperactivity in Down syndrome

Down syndrome, caused by trisomy 21, is characterized by chronic interferon-associated inflammation and immune dysregulation, yet the contribution of human secondary lymphoid organs to shaping this immune landscape remains unclear. Using multimodal single-cell and spatial profiling of human tonsils, we identify extensive remodeling of immune organization in trisomy 21. CD4 T cells are skewed away from canonical follicular helper (TFH) programs toward inflammatory TFH1-like and cytotoxic helper states enriched for interferon-responsive transcriptional programs. Tonsillar TFH cells exhibit increased interferon-{gamma} and interleukin-21 production, indicating inflammatory skewing toward type 1 helper immunity. These alterations are accompanied by changes in dendritic cell and CD8 T-cell compartments, reduced follicular size, increased extrafollicular TFH1-B-cell proximity and altered B-cell differentiation trajectories. Together, our findings identify trisomy 21 as a unique human context to investigate how chronic interferon-associated inflammation reshapes lymphoid tissue organization and adaptive immune cell fate decisions.

immunology↗

bioRxiv2026

Progressive deterioration of adaptive immune repertoires in Down syndrome linked to interferon hyperactivity and lymphoid tissue disorganization

Persons with Down syndrome (DS), the genetic condition caused by trisomy 21 (T21), display strong dysregulation of adaptive immunity, which underlies high risk of complications from infections, widespread autoimmunity, and poor vaccine responses. However, the mechanisms by which T21 dysregulates adaptive immunity across the lifespan remain poorly understood. We report here a multimodal analysis of adaptive immunity across development and aging in DS, including deep B cell profiling by mass cytometry matched to transcriptome and proteome data, B and T cell receptor sequencing (BCR, TCR), and spatial transcriptomics of tonsil tissue. T21 causes progressive shifts in B cell subsets together with accelerated age-dependent B cell loss linked to hyperactive interferon and JAK/STAT signaling. The peripheral immunoglobulin repertoire shows dysregulated class switching, progressive loss of diversity, differential VDJ usage, and imbalanced rates of somatic hypermutation across immunoglobulin isotypes mirrored by contraction and skewing of the TCR repertoire. In children with DS, tonsil tissues are highly disorganized with smaller germinal centers, fibrotic intrusions, lower rates of cell proliferation, strong inflammatory signaling, and transcriptional programs indicative of dysregulated lymphocyte homing and residence. Together, these results point to hyperactive interferon signaling as a driver of dysregulated adaptive immunity in DS amenable to early therapeutic intervention.

immunology↗

bioRxiv2026

Trisomy 21 cerebral organoids exhibit Alzheimer's disease amyloid and apolipoprotein E co-pathologies

Adults with Down syndrome (DS) develop Alzheimers disease (AD) brain pathology by age 40 due to triplication of the Amyloid Precursor Protein (APP) gene on chromosome 21. Inheritance of the apolipoprotein E-e4 (APOE4) allele of the APOE gene on chromosome 19 remains the greatest genetic risk factor for AD in the typical population, yet its role in DS-associated AD (DS-AD) neuropathogenesis in people with DS is unclear. We generated human induced pluripotent stem cell (hiPSC)-derived neurons, astrocytes, and cerebral organoids (COs) using cells from people with DS and from euploid individuals. Aged DS COs were smaller than aged euploid COs and showed robust amyloid-{beta} neuropathology that was positively correlated with the levels of apoE expression. We then captured extracellular vesicles (EVs) from the conditioned media of COs and observed a decrease in the levels of secreted AD-related proteins, including amyloid, contained within the EVs and in the media from which the EVs were isolated. We also identified distinct neuronal and astrocytic gene expression signatures in DS COs relative to euploid COs, including a set of genes known to interact with both APOE and APP at the gene and/or protein levels. Lastly, we determined that, despite differences in the expression levels of the specific genes involved, several common pathways were upregulated in T21 hiPSC-derived neurons, astrocytes, and COs, including apoptosis, the endolysosome, and structural stabilization pathways. Taken together, our findings provide novel insights into molecular mechanisms that may contribute to DS-AD and indicate that apoE plays an important role in the disease process.

neuroscience↗

bioRxiv2026

An AI-Powered Trisomy 21 Research Assistant

Down syndrome, caused by trisomy 21, increases the risk of diverse co-occurring conditions. With more than 34,000 related publications indexed in PubMed as of early 2026, keeping pace with this expanding literature is challenging. While general-purpose large language models are widely used for information retrieval, they often rely on broad training data rather than specific evidence. Retrieval-augmented generation (RAG) improves rigor and reliability of responses by linking model outputs to source texts. In research, source texts are peer-reviewed articles. Standard implementations treat all manuscript sections equally, allowing background text to rank as highly as experimental results. To focus model outputs on experimentally supported responses, we developed the T21 Research Assistant, a section-aware RAG system that prioritizes Results sections to ground responses in primary experimental evidence. The system draws exclusively from 1,789 open-access Down syndrome publications from PubMed Central, including 327 NIH INCLUDE-funded studies, and uses a multistage pipeline for query validation, retrieval, reranking, synthesis, and citation verification. Built on NVIDIA Nemotron models, it generates structured, cited responses. Evaluation using expert-curated questions demonstrated strong performance, achieving a BERTScore F1 of 0.712 and recall of 0.758, comparable to or exceeding leading proprietary and open-source models. T21 Research Assistant is available at: https://bioinformatics.cuanschutz.edu/t21-res-assi/

bioinformatics↗

bioRxiv2026

Attenuated estrogen signaling disrupts placentation and drives trophoblast defects in Down syndrome

Proper establishment of the primitive placenta and subsequent tissue homeostasis in the mature placenta are critical for successful pregnancy in humans. Placental insufficiency is associated with adverse pregnancy outcomes, including fetal growth restriction, preeclampsia, and pregnancy loss. Moreover, emerging evidence suggests that placental defects are associated with long-term health challenges that manifest well into adulthood; yet the etiologies of such diseases are largely unknown. Defining the mechanistic basis for placental deficiencies, therefore, has important implications for improving both reproductive health and the lifelong well-being of affected children. Down syndrome is characterized by placental defects of unknown mechanistic origin, and notably, individuals with Down syndrome are at increased risk of developing diseases commonly associated with placental insufficiency later in life. Using induced pluripotent stem cells from Down syndrome patients, we found that stem cell-based embryo models (i.e., blastoids) and directed differentiation systems recapitulate trophoblast cell fate defects observed in placentas affected by Down syndrome. Furthermore, we demonstrate that attenuated estrogen signaling contributes to placental syncytialization defects and identify NRIP1, a transcriptional corepressor of estrogen receptor that is located on chromosome 21, as a key driver of trophoblast cell fate defects. Increased gene dosage of NRIP1 in an otherwise diploid cell line phenocopies cell fate defects observed in trophoblasts affected by Down syndrome. Our study suggests that estrogen signaling is a crucial regulator of trophoblast development and may serve as a potential target for therapeutic intervention. Highlights and eTOC blurbO_LIEstrogen signaling mediates syncytiotrophoblast fusion C_LIO_LIHuman iPS cells provide a tractable model for trophoblast defects in Down syndrome C_LIO_LITrophoblast differentiation and estrogen signaling are disrupted in Down syndrome C_LIO_LIIncreased NRIP1 expression is sufficient to induce trophoblast defects C_LI Logsdon and colleagues apply patient-derived induced pluripotent stem cells to recapitulate placentation defects observed in Down syndrome. The authors demonstrate that attenuated estrogen signaling disrupts trophoblast differentiation and identify NRIP1, a gene found on chromosome 21 that dampens estrogen signaling, as a regulator of trophoblast maturation. NRIP1 and estrogen signaling may represent important therapeutic targets for infertility and Down syndrome.

developmental biology↗

bioRxiv2025

Altered Hepatic Metabolism in Down Syndrome

Trisomy 21 (T21) gives rise to Down syndrome (DS), the most commonly occurring chromosomal abnormality in humans. T21 affects nearly every organ and tissue system in the body, predisposing individuals with DS to congenital heart defects, autoimmunity, and Alzheimers disease, among other co-occurring conditions. Here, using multi-omic analysis of plasma from more than 400 people, we report broad metabolic changes in the population with DS typified by increased bile acid levels and protein signatures of liver dysfunction. In a mouse model of DS, we demonstrate conservation of perturbed bile acid metabolism accompanied by liver pathology. Bulk RNA-sequencing revealed widespread impacts of the Dp16 model on hepatic metabolism and inflammation, while single-cell transcriptomics highlighted cell types associated with these observations. Modulation of dietary fat profoundly impacted gene expression, bile acids, and liver pathology. Overall, these data represent evidence for altered hepatic metabolism in DS that could be modulated by diet.

genetics↗

bioRxiv2025

Elevated mitochondrial metabolism in Down syndrome iPSCs reduces commitment to neuroectoderm

A key feature of Down syndrome (DS) is reduced neurogenesis. Here, we provide evidence that increased mitochondrial metabolism in DS stem cells reduces their ability to commit to neuroectoderm (NE), one of the earliest steps in the development of the nervous system. We show that mitochondria in induced pluripotent stem cells derived from individuals with DS (3S-iPSCs) have a higher membrane potential and increased capacity for calcium uptake via the mitochondrial calcium uniporter (MCU) compared to isogenic, euploid controls. Consequently, 3S-iPSCs proliferate faster and spend less time in G1 of the cell cycle. This reduces the opportunity for growth of a primary cilium, an important developmental signaling hub. Inhibiting MCU or slowing proliferation of 3S-iPSCs is sufficient to increase ciliation and improve commitment to NE. In summary, we provide evidence that a mitochondria-to-cilia signaling axis important during the earliest steps of neurogenesis is dysregulated in DS, yet remains amenable to small molecule intervention.

developmental biology↗

bioRxiv2023

Mediator kinase inhibition suppresses hyperactive interferon signaling in Down syndrome

Hyperactive interferon (IFN) signaling is a hallmark of Down syndrome (DS), a condition caused by trisomy 21 (T21); strategies that normalize IFN signaling could benefit this population. Mediator-associated kinases CDK8 and CDK19 drive inflammatory responses through incompletely understood mechanisms. Using sibling-matched cell lines with/without T21, we investigated Mediator kinase function in the context of hyperactive IFN in DS over a 75min - 24h timeframe. Activation of IFN-response genes was suppressed in cells treated with the CDK8/CDK19 inhibitor cortistatin A (CA), via rapid suppression of IFN-responsive transcription factor (TF) activity. We also discovered that CDK8/CDK19 affect splicing, a novel means by which Mediator kinases control gene expression. To further probe Mediator kinase function, we completed cytokine screens and metabolomics experiments. Cytokines are master regulators of inflammatory responses; by screening 105 different cytokine proteins, we show that Mediator kinases help drive IFN-dependent cytokine responses at least in part through transcriptional regulation of cytokine genes and receptors. Metabolomics revealed that Mediator kinase inhibition altered core metabolic pathways in cell type-specific ways, and broad up-regulation of anti-inflammatory lipid mediators occurred specifically in kinase-inhibited cells during hyperactive IFN{gamma} signaling. A subset of these lipids (e.g. oleamide, desmosterol) serve as ligands for nuclear receptors PPAR and LXR, and activation of these receptors occurred specifically during hyperactive IFN signaling in CA-treated cells, revealing mechanistic links between Mediator kinases, lipid metabolism, and nuclear receptor function. Collectively, our results establish CDK8/CDK19 as context-specific metabolic regulators, and reveal that these kinases control gene expression not only via TFs, but also through metabolic changes and splicing. Moreover, we establish that Mediator kinase inhibition antagonizes IFN signaling through transcriptional, metabolic, and cytokine responses, with implications for DS and other chronic inflammatory conditions.

biochemistry↗

bioRxiv2023

Metabolic signatures of cardiorenal dysfunction in plasma from sickle cell patients, as a function of therapeutic transfusion and hydroxyurea treatment

Metabolomics studies in sickle cell disease (SCD) have been so far limited to tens of samples, owing to technical and experimental limitations. To overcome these limitations, we performed plasma metabolomics analyses on 596 samples from patients with sickle cell sickle cell disease (SCD) enrolled in the WALK-PHaSST study. Clinical covariates informed the biological interpretation of metabolomics data, including genotypes (hemoglobin SS, hemoglobin SC), history of recent transfusion (HbA%), response to hydroxyurea treatment (HbF%). We investigated metabolic correlates to the degree of hemolysis, cardiorenal function, as determined by tricuspid regurgitation velocity (TRV), estimated glomerular filtration rate (eGFR), and overall hazard ratio (unadjusted or adjusted by age). Recent transfusion events or hydroxyurea treatment were associated with elevation in plasma free fatty acids and decreases in acyl-carnitines, urate, kynurenine, indoles, carboxylic acids, and glycine- or taurine-conjugated bile acids. High levels of these metabolites, along with low levels of plasma S1P and L-arginine were identified as top markers of hemolysis, cardiorenal function (TRV, eGFR), and overall hazard ratio. We thus uploaded all omics and clinical data on a novel online portal that we used to identify a potential mechanism of dysregulated red cell S1P synthesis and export as a contributor to the more severe clinical manifestations in patients with the SS genotype compared to SC. In conclusion, plasma metabolic signatures - including low S1P, arginine and elevated kynurenine, acyl-carnitines and bile acids - are associated with clinical manifestation and therapeutic efficacy in SCD patients, suggesting new avenues for metabolic interventions in this patient population.

biochemistry↗

bioRxiv2022

Enhanced Effector Activity of Mediator Kinase Module Deficient CAR-T Cells

Adoptive T cell immune therapies mediate impressive clinical benefit in a fraction of patients, but anti-tumor effects are often limited by inadequate T cell potency. To identify genes limiting T cell effector function, we conducted genome-wide CRISPR knock-out screens in human primary CAR-T cells. The top hits were MED12 and CCNC, components of the cyclin-dependent kinase (CDK) module of the Mediator complex, an evolutionarily conserved regulator of gene transcription. MED12 or CCNC deficient CAR-T cells manifest increased expansion, cytokine production, metabolic fitness, effector function, anti-tumor activity and reduced terminal effector differentiation. Chemical inhibition of CDK8/19 kinase activity recapitulated some features of genetic loss of MED12, including increased T cell expansion. MED12 deficient CAR-T cells showed widespread but selective increases in chromatin accessibility, MED1 chromatin occupancy, and H3K27 acetylation at enhancers used by transcription factors playing a critical role in T cell fate, including several STAT and AP1 family members. The most pronounced enhancement was observed for STAT5 which manifested as increased sensitivity to IL-2 in MED12 deficient T cells. These results link Mediator induced transcriptional coactivation with T cell effector programming and identify the CDK module as a target for enhancing the potency of anti-tumor T cell responses. One Sentence SummaryThe Mediator kinase module is a primary regulator of T cell differentiation, and genetic or small molecule-based inhibition of this module enhances effector T cell potency.

immunology↗

bioRxiv2022

Interferon receptor gene dosage determines multiple hallmarks of Down syndrome

Trisomy 21 causes Down syndrome, a condition characterized by cognitive impairments, immune dysregulation, and atypical morphogenesis. Using whole blood transcriptome analysis, we demonstrate that specific overexpression of four interferon receptors encoded on chromosome 21 associates with chronic interferon hyperactivity and systemic inflammation in Down syndrome. To define the contribution of interferon receptor overexpression to Down syndrome phenotypes, we used genome editing to correct interferon receptor gene dosage in mice carrying triplication of a large genomic region orthologous to human chromosome 21. Normalization of interferon receptor copy number attenuated lethal antiviral responses, prevented heart malformations, decreased developmental delays, improved cognition and normalized craniofacial anomalies. Therefore, interferon receptor gene dosage determines major hallmarks of Down syndrome, indicating that trisomy 21 elicits an interferonopathy amenable to therapeutic intervention. One-Sentence SummaryCorrection of interferon receptor gene dosage rescues multiple key phenotypes in a mouse model of trisomy 21.

genetics↗

bioRxiv2021

Trisomy 21 induces pericentrosomal crowding disrupting early stages of primary ciliogenesis and mouse cerebellar development

Primary cilia are signaling organelles essential for development and homeostasis. Loss of primary cilia is lethal, and decreased or defective cilia cause multisystemic conditions called ciliopathies. Down syndrome shares clinical overlap with ciliopathies. We previously showed that trisomy 21 diminishes primary cilia formation and function due to elevated Pericentrin, a centrosome protein encoded on chromosome 21. Pericentrin is mislocalized, creating aggregates that disrupt pericentrosomal trafficking and microtubule organization. Here, we examine the cilia-related molecules and pathways disrupted in trisomy 21 and their in vivo phenotypic relevance. Utilizing ciliogenesis time course experiments, we reveal how Pericentrin, microtubule networks, and components of ciliary vesicles are reorganized for ciliogenesis in euploid cells. Early in ciliogenesis, chromosome 21 polyploidy results in elevated Pericentrin and microtubule networks away from the centrosome that ensnare MyosinVA and EHD1, blocking mother centriole uncapping that is essential for ciliogenesis. Ciliated trisomy 21 cells have persistent trafficking defects that reduce transition zone protein localization, which is critical for Sonic hedgehog signaling. Sonic hedgehog signaling is decreased and anticorrelates with Pericentrin levels in trisomy 21 primary mouse embryonic fibroblasts. Finally, we observe decreased ciliation in vivo. A mouse model of Down syndrome with elevated Pericentrin has fewer primary cilia in cerebellar granule neuron progenitors and thinner external granular layers. Our work reveals that elevated Pericentrin in trisomy 21 disrupts multiple early steps of ciliogenesis and creates persistent trafficking defects in ciliated cells. This pericentrosomal crowding results in signaling defects consistent with the neurological deficits found in individuals with Down syndrome.

cell biology↗

bioRxiv2021

Trisomy 21 increases microtubules and disrupts centriolar satellite localization

Trisomy 21, the cause of Down syndrome, causes a 0.5-fold protein increase of the chromosome 21-resident gene Pericentrin (PCNT) and reduces primary cilia formation and signaling. Here we investigate the mechanisms by which PCNT imbalances disrupt cilia. Using isogenic RPE-1 cells with increased chromosome 21 dosage, we find PCNT protein accumulates around the centrosome as a pericentrosomal cluster of enlarged cytoplasmic puncta that localize along and at MT ends. Cytoplasmic PCNT puncta impact the intracellular MT trafficking network required for primary cilia, as the PCNT puncta sequester cargo peripheral to centrosomes in what we call pericentrosomal crowding. The centriolar satellite proteins, PCM1, CEP131 and CEP290, important for ciliogenesis, accumulate at sites of enlarged PCNT puncta in trisomy 21 cells. Reducing PCNT when chromosome 21 ploidy is elevated is sufficient to decrease PCNT puncta, reestablish a normal density of MTs around the centrosome, restore ciliogenesis to wild type levels and decrease pericentrosomal crowding. A transient reduction in MTs also decreases pericentrosomal crowding and partially rescues ciliogenesis in trisomy 21 cells, indicating that increased PCNT leads to defects in the microtubule network deleterious to normal centriolar satellite distribution. We propose that chromosome 21 aneuploidy disrupts MT-dependent intracellular trafficking required for primary cilia. TOCMcCurdy et al explore why elevated Pericentrin in trisomy 21 negatively impacts primary cilia formation and signaling. They find that elevated Pericentrin produces more pericentrosomal puncta that associates with and increases microtubules. Changes to Pericentrin and microtubules mislocalizes centriolar satellites in a pericentrosomal crowd.

cell biology↗

bioRxiv2021

Sonic Hedgehog Pathway Modulation Normalizes Expression of Olig2 in Rostrally Patterned NPCs with Trisomy 21

The intellectual disability found in people with Down syndrome (DS) is associated with a decrease in white matter in the central nervous system. To study the mechanism of this myelination deficit, we differentiated two isogenic lines of induced pluripotent stem cells (iPSCs) derived from people with DS into brain-like and spinal cord-like neural progenitor cells (NPCs) and promoted a transition towards oligodendroglial fate by activating the Sonic hedgehog (SHH) pathway. In the spinal cord-like trisomic cells, we found no difference in expression of OLIG2 or NKX2.2, two transcription factors essential for commitment to the oligodendrocyte (OL) lineage. However, in the brain-like trisomic NPCs, OLIG2 is significantly upregulated and is associated with reduced expression of NKX2.2. We found that this gene dysregulation and block in NPC transition can be normalized by increasing the concentration of a SHH pathway agonist (SAG) during differentiation. These results underscore the importance of regional and cell type differences in gene expression in DS and demonstrate that modulation of SHH signaling in trisomic cells can rescue an early perturbed step in neural lineage specification in DS.

neuroscience↗

bioRxiv2020

HERC1 regulates breast cancer cells migration and invasion

Tumor cell migration and invasion into adjacent tissues is one of the hallmarks of cancer and the first step towards secondary tumors formation, which represents the leading cause of cancer-related deaths. This process is considered an unmet clinical need in the treatment of this disease, particularly in breast cancers characterized by high aggressiveness and metastatic potential. In order to identify and characterize genes with novel functions as regulators of tumor cell migration and invasion, we performed a genetic loss-of-function screen using a shRNA library directed against the Ubiquitin Proteasome System (UPS) in a highly invasive breast cancer derived cell line. Among the candidates, we validated HERC1 as a gene regulating cell migration and invasion. Furthermore, using animal models, our results indicated that HERC1 silencing affects primary tumor growth and lung colonization. Finally, we conducted an in-silico analysis using publicly available protein expression data and observed an inverse correlation between HERC1 expression levels and breast cancer patients overall survival. Altogether, our findings demonstrate that HERC1 might represent a novel therapeutic target for the development or improvement of breast cancer treatment.

cancer biology↗

bioRxiv2020

USP19 modulates cancer cell migration and invasion and acts as a novel prognostic marker in patients with early breast cancer

Tumor cell dissemination in cancer patients is associated with a significant reduction in their survival and quality of life. The ubiquitination pathway plays a fundamental role in the maintenance of protein homeostasis both in normal and stressed conditions and its dysregulation has been associated with malignant transformation and invasive potential of tumor cells, thus highlighting its value as a potential therapeutic target. In order to identify novel molecular targets of tumor cell migration and invasion we performed a genetic screen with an shRNA library against ubiquitination pathway-related genes. To this end, we set up a protocol to specifically enrich positive migration regulator candidates. We identified the deubiquitinase USP19 and demonstrated that its silencing reduces the migratory and invasive potential of highly invasive breast cancer cell lines. We extended our investigation in vivo and confirmed that mice injected with USP19 depleted cells display increased tumor-free survival, as well as a delay in the onset of the tumor formation and a significant reduction in the appearance of metastatic foci, indicating that tumor cell invasion and dissemination is impaired. In contrast, overexpression of USP19 increased cell invasiveness both in vitro and in vivo, further validating our findings. More importantly, we demonstrated that USP19 catalytic activity is important for the control of tumor cell migration and invasion, and that its molecular mechanism of action involves LRP6, a Wnt co-receptor. Finally, we showed that USP19 overexpression is a surrogate prognostic marker of distant relapse in patients with early breast cancer. Altogether, these findings demonstrate that USP19 might represent a novel therapeutic target in breast cancer.

cancer biology↗

bioRxiv2019

p53-induced apoptosis is specified by a translation program regulated by PCBP2 and DHX30.

Activation of p53 by the small molecule Nutlin can result in a combination of cell cycle arrest and apoptosis. The relative strength of these events is difficult to predict by classical gene expression analysis, leaving uncertainty as to the therapeutic benefits of Nutlin. Here, we report a new translational control mechanism shaping p53-dependent apoptosis. Using polysome profiling, we establish Nutlin-induced apoptosis to be associated with the enhanced translation of mRNAs carrying multiple copies of a newly identified 3UTR CG-rich motif mediating p53-dependent death (CGPD-motif). We identified PCBP2 and DHX30 as CGPD-motif interactors. We found that in cells undergoing persistent cell cycle arrest in response to Nutlin, CGPD-motif mRNAs are repressed by the PCBP2-dependent binding of DHX30 to the motif. Thus, upon DHX30 depletion in these cells, the translation of CGPD-motif mRNAs is increased, and the response to Nutlin shifts towards apoptosis. Instead, DHX30 inducible overexpression in SJSA1 cells, that undergo Nutlin-induced apoptosis, leads to decreased translation of CGPD-motif mRNAs. Overall, this work establishes the role of PCBP2-DHX30 in controlling the translation of CGPD-motif mRNAs and thus provide a new mechanism to modulate the induction of p53-dependent apoptosis.

molecular biology↗