Biology subjects

Vivero, M.

Publications and source records attributed to Vivero, M..

4 recordsLinked to original sources

bioRxiv2025

EED Maintains the Small Cell Lung Cancer Neuroendocrine Phenotype and Drives Lung Cancer Histological Transformation

Lung cancer histological subtypes include lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC). While typically distinct, combined LUAD/SCLC histology tumors occur, and LUAD can transform into SCLC as a resistance mechanism to targeted therapies, especially in EGFR-Mutant LUADs with RB1/TP53-inactivation. Although PRC2 complex expression increases during this transformation, its functional role has remained unclear. Using CRISPR-based autochthonous immunocompetent GEMMs, we demonstrate that inactivation of EED, the core PRC2 scaffolding subunit, impairs SCLC tumorigenesis and drives histological transformation from ASCL1-positive SCLC to LUAD through a transient NEUROD1-positive intermediate state. Mechanistically, EED loss de-represses bivalent genes co-marked by H3K27me3 and H3K4me3, including LUAD oncogenic RAS, PI3K, and MAPK pathway genes, to promote transformation to LUAD. Consistently, these same signaling genes are bivalently repressed in human SCLC patient-derived xenograft (PDX) tumors, suggesting a conserved PRC2-dependent mechanism to repress LUAD lineage oncogenic signaling to maintain the SCLC neuroendocrine identity. In a complementary EGFR-mutant LUAD GEMM with RB1/TP53 inactivation, EED was required for LUAD-to-SCLC transformation and distant metastasis upon EGFR withdrawal. These findings identify the PRC2 complex as a key epigenetic enforcer of SCLC neuroendocrine identity and nominate EED inhibition as a potential strategy to block SCLC transformation in high-risk LUAD.

cancer biology↗

bioRxiv2025

MAPK Signaling and Angiopoietin-2 Contribute to Endothelial Permeability in Capillary Malformations

Capillary malformations (CM) are slow-flow vascular abnormalities present at birth and predominantly manifest as cutaneous lesions. In the rare neurocutaneous disorder known as Sturge Weber Syndrome (SWS), individuals exhibit CM not only on the skin but also within the leptomeninges of the brain and the choroid of the eye. >90% of CM are caused by a somatic R183Q mutation in GNAQ, the gene encoding Gq - a heterotrimeric G-protein subunit. The somatic GNAQ mutation is notably enriched in endothelial cells (ECs) isolated from CM-affected regions. Here we show blood vessels in cutaneous and leptomeningeal SWS lesions exhibit extravascular fibrin indicating a compromised endothelial barrier. Longitudinal MRI of the brain in one SWS patient further suggests vascular permeability. To explore this pathological phenotype, we employed the trans-endothelial electrical resistance (TEER) assay to measure permeability of the EC-EC barrier in vitro. Human EC CRISPR edited to create a GNAQ R183Q allele (EC-R183Q) exhibited a reduced barrier compared to mock edited EC (EC-WT). We sought to identify signaling molecules needed for EC barrier formation. Knockdown of angiopoietin-2 (ANGPT2), known to be significantly increased in EC-R183Q and in CM, partially yet significantly restored the barrier, while an anti-ANGPT2 function blocking antibody did not. We next tested the MEK1,2 inhibitor (Trametinib) because MAPK signaling is increased by GNAQ mutation. MEK1,2 inhibitors partially restored the EC barrier, implicating involvement of MAPK/ERK signaling. The combination of ANGPT2 knockdown and Trametinib significantly restored the EC barrier to near EC-WT levels. The additive impacts of ANGPT knockdown and MEK1,2 inhibition indicate the two operate in separate pathways. In summary, we discovered that GNAQ p.R183Q ECs exhibit compromised endothelial barrier formation, reflecting the compromised EC barrier in CM lesions, and that ANGPT2 knockdown combined with Trametinib effectively restores the EC-EC barrier. NONSTANDARD ABBREVIATIONS AND ACRONYMS O_TBL View this table: org.highwire.dtl.DTLVardef@e1081eorg.highwire.dtl.DTLVardef@1dc05b7org.highwire.dtl.DTLVardef@1fb6ac0org.highwire.dtl.DTLVardef@11d8f59org.highwire.dtl.DTLVardef@1ae5406_HPS_FORMAT_FIGEXP M_TBL C_TBL NOVELTY AND SIGNIFICANCEO_ST_ABSWhat is known?C_ST_ABSO_LIThe mutant Gq-R183Q in endothelial cells activates phospholipase {beta}3, contributing to increased angiopoietin-2, a pro-angiogenic, proinflammatory molecule that contributes to vascular permeability. C_LIO_LIEndothelial Gq-R183Q is sufficient to drive formation of enlarged blood vessels akin to what is observed in CM. ANGPT2 shRNA knockdown prevented the enlarged vessel phenotype in a xenograft model. C_LIO_LIAn EC-specific GNAQ p.R183Q mouse model showed permeability in brain vessels, detected by perfusion of Evans Blue dye, indicating reduced vascular integrity. C_LI What New Information Does This Article Contribute?O_LIReduced vascular integrity in CM is confirmed by Martius Scarlet Blue staining and longitudinal MRI imaging of SWS brain. C_LIO_LIGNAQ p.R183Q EC form a weaker endothelial barrier in vitro compared to control ECs. The weakened endothelial barrier in the mutant ECscan be rescued by Gq inhibitor, YM254890, confirming the compromised barrier is a consequence of the mutant Gq. C_LIO_LITitration experiments modeling the mosaic nature of the GNAQ p.R183Q in CMshow that 5- 10% GNAQ p.R183Q EC in the monolayer is sufficient to reduce endothelial barrier formation. C_LIO_LIKnockdown of ANGPT2 or MEK1,2 inhibition partially restored the endothelial barrier in GNAQ p.R183Q EC. C_LIO_LICombining knockdown of ANGPT2 and addition of a MEK inhibitor, Trametinib, restored the endothelial barrier to near what is seen in wild type ECs. C_LI What is the translational message?Sturge Weber Syndrome (SWS) is a neurocutaneous disorder that involves atypical blood vessel overgrowth in the skin, brain and eye. It is associated with facial CM (aka port wine birthmark), leptomeningeal CM in the brain visible with MRI, and glaucoma. Theneurological sequalae involve seizures, cerebral atrophies and calcification, and intellectual disorders. Currently there are no molecularly targeted therapies for non-syndromic CM or SWS. Our study shows the involvement of MAPK pathway and the proinflammatory molecule ANGPT2 in endothelial permeability and suggests a path to target GNAQ p.R183Q driven CM.

pathology↗

bioRxiv2024

Leukemia inhibitory factor (LIF) receptor amplifies pathogenic activation of fibroblasts in lung fibrosis

Fibrosis drives end-organ damage in many diseases. However, clinical trials targeting individual upstream activators of fibroblasts, such as TGF{beta}, have largely failed. Here, we target the leukemia inhibitory factor receptor (LIFR) as a "master amplifier" of multiple upstream activators of lung fibroblasts. In idiopathic pulmonary fibrosis (IPF), the most common fibrotic lung disease, we found that lung myofibroblasts had high LIF expression. Further, TGF{beta}1, one of the key drivers of fibrosis, upregulated LIF expression in IPF fibroblasts. In vitro anti-LIFR antibody blocking on human IPF lung fibroblasts reduced induction of profibrotic genes downstream of TGF{beta}1, IL-4 and IL-13. Further, siRNA silencing of LIFR in IPF precision cut lung slices reduced expression of fibrotic proteins. Together, we find that LIFR drives an autocrine positive feedback loop that amplifies and sustains pathogenic activation of IPF fibroblasts downstream of multiple external stimuli, implicating LIFR as a therapeutic target in fibrosis. Significance StatementFibroblasts have a central role in the pathogenesis of fibrotic diseases. However, due to in part to multiple profibrotic stimuli, targeting a single activator of fibroblasts, like TGF{beta}, has not yielded successful clinical treatments. We hypothesized that a more effective therapeutic strategy is identifying a downstream "master amplifier" of a range of upstream profibrotic stimuli. This study identifies the leukemia inhibitory factor receptor (LIFR) on fibrotic lung fibroblasts amplifies multiple profibrotic stimuli, such as IL-13 and TGF{beta}. Blocking LIFR reduced fibrosis in ex vivo lung tissue from patients with idiopathic pulmonary fibrosis (IPF). LIFR, acting as a master amplifier downstream of fibroblast activation, offers an alternative therapeutic strategy for fibrotic diseases.

cell biology↗

bioRxiv2021

Cross-tissue, single-cell stromal atlas identifies shared pathological fibroblast phenotypes in four chronic inflammatory diseases

Pro-inflammatory fibroblasts are critical to pathogenesis in rheumatoid arthritis, inflammatory bowel disease, interstitial lung disease, and Sjogrens syndrome, and represent a novel therapeutic target for chronic inflammatory disease. However, the heterogeneity of fibroblast phenotypes, exacerbated by the lack of a common cross-tissue taxonomy, has limited the understanding of which pathways are shared by multiple diseases. To investigate, we profiled patient-derived fibroblasts from inflamed and non-inflamed synovium, intestine, lung, and salivary glands with single-cell RNA-sequencing. We integrated all fibroblasts into a multi-tissue atlas to characterize shared and tissue-specific phenotypes. Two shared clusters, CXCL10+CCL19+ immune-interacting and SPARC+COL3A1+ vascular-interacting fibroblasts were expanded in all inflamed tissues and additionally mapped to dermal analogues in a public atopic dermatitis atlas. We further confirmed these human pro-inflammatory fibroblasts in animal models of lung, joint, and intestinal inflammation. This work represents the first cross-tissue, single-cell fibroblast atlas revealing shared pathogenic activation states across four chronic inflammatory diseases.

genomics↗