bioRxiv Science⌕ Search

Biology subjects

Nasias, D.

Publications and source records attributed to Nasias, D..

2 recordsLinked to original sources

Cross-species analysis identifies genotype-driven vulnerabilities in lung adenocarcinoma

While three major genetic alteration subsets, characterized by mutations in STK11, KRAS, and EGFR, are seminal in driving tumorigenesis in LUAD, their distinct effects on tumor cells and the tumor microenvironment are not fully understood. Here, we map critical oncogenic subset-specific vulnerabilities by identifying conserved cell-type-specific reprogrammings between human and mouse LUAD. Through harmonized scRNA-seq analysis of 57 human and 18 mouse specimens, we unveil that genetic alterations impose genotype-specific immune imprints on the tumor microenvironment: KRAS is associated with a transitional immune state, whereas STK11 and EGFR mutations define discrete and contrasting immune phenotypes. We find that STK11-mutant tumors exhibit complement and interferon-rich immune microenvironments while EGFR-mutant tumors harbor a naive T cell-rich phenotype accompanied by a global HLA downregulation, stress-responsive alveolar macrophages marked by MARCO. In the epithelial compartments, cross-species analysis reveals metabolic dependencies, including OGDH in EGFR- and PDE4D in STK11-mutant cells. Statement of SignificanceThis study delineates oncogenotype-specific molecular and immune imprints in lung adenocarcinoma, revealing STK11-, KRAS-, and EGFR-mutated tumors as transcriptionally and immunologically discrete ecosystems. By mapping epithelial vulnerabilities alongside immune imprints, we unveil genotype-imposed dependencies that inform the rational development of precision therapies with direct translational relevance.

cancer biology↗

Extracellular vesicles from chylomicron-treated endothelial cells drive macrophage inflammation

BackgroundMovement of circulating lipids into tissues and arteries requires transfer across the endothelial cell barrier. This process allows the heart to obtain fatty acids (FAs), its chief source of energy and apolipoprotein B (apoB)-containing lipoproteins to cross the arterial endothelial barrier leading to cholesterol accumulation in the subendothelial space. Multiple studies have established elevated postprandial triglyceride-rich lipoproteins (TRLs) as an independent risk factor for cardiovascular disease (CVD). We explored how chylomicrons affect ECs and transfer their FAs across the EC barrier. MethodsWe had reported that media from chylomicron-treated ECs leads to lipid droplet (LD) formation in macrophages. To determine the responsible component of this media, we assessed whether removing the extracellular vesicles (EVs) would obviate this effect. EVs from control and treated cells were then characterized by protein, lipid and microRNA (miR) content. We also studied the EV-induced transcription changes in macrophages and ECs and whether knockdown of scavenger receptor-BI (SR-BI) altered these responses. In addition, using chylomicrons labeled with [13C]oleate, we studied the uptake and release of this labed by ECs. ResultsChylomicron treatment of ECs led to an inflammatory response that included production of EVs that drove macrophage LD accumulation. The EVs contained little free fatty acids and triglyceride, but abundant phospholipids and diacylglycerols. In concert with this, [13]C labeled chylomicron triglycerides exited ECs primarily in phospholipids. EVs from chylomicron treated versus untreated ECs were larger, more abundant, and contained specific miRs. Treatment of macrophages and naive ECs with media from chylomicron-treated ECs increased expression of inflammatory genes. ConclusionsEC chylomicron metabolism produces EVs that increase macrophage inflammation and create LDs. Media containing these EVs also increases EC inflammation, illustrating an autocrine inflammatory process. FAs within chylomicron triglycerides are converted to phospholipids within EVs. Thus, EC uptake of chylomicrons constitutes an important pathway for vascular inflammation and tissue lipid acquisition.

cell biology↗