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Biology subjects

Gari, M.

Publications and source records attributed to Gari, M..

2 recordsLinked to original sources

Generalized inference of noise-corrected state variability in single cells

Single-cell omics methods operate at their detection limit and are less conducive to technical controls than mini-bulk approaches, which combine cells of the same type before profiling. To integrate mini-bulk samples with paired split-pool controls more holistically, we built stochprofIC, an algorithm that considers data, noise, and covariates in a distributional-regression framework. We vet stochprofIC with synthetic datasets and compare against an adjusted-variance alternative using mini-bulk data in mouse brains and human breast cancers. The noise-batch corrections provided by stochprofIC enable inference of the single-cell populations comprising the mini-bulk, which are validated repeatedly by RNA FISH in different contexts. We use stochprofIC outputs as input to a systems model of nucleocytoplasmic transport and distinguish heterogeneous trafficking states. Pharmacologic inhibition of a MAP3K11-high state inhibits apoptosis in primary breast-cancer organoids, supporting relevance to phenotypes. By deconvolving changes in location and scale, stochprofIC supports mini-bulking when high-sensitivity and reliability profiles are important.

systems biology↗

Exosomes are specialized vehicles to induce fibronectin assembly

Fibronectin is a key stromal matrix molecule whose assembly into fibrils is thought to require cells. In contrast, we find that small exosome-type extracellular vesicles (EVs) are critical initiators of fibronectin assembly. Fibroblasts engineered to be deficient in exosome secretion showed greatly reduced assembly of fibronectin and other stromal matrix molecules in 2D, 3D, and in vivo environments, and led to reduced tumor growth and lung metastasis by breast cancer cells. Furthermore, transgenic mice with defects in exosome secretion had greatly reduced lung fibrosis after treatment with bleomycin. In a direct test of exosome function, we find that the addition of purified small EVs to purified soluble fibronectin in a cell-free system is sufficient to induce fibronectin assembly. The EV-induced fibronectin assembly requires the presence of fibronectin-binding integrins and Syndecan-1 in the EVs. We propose a new model in which secreted exosomes directly drive stromal matrix assembly and tissue fibrosis.

cell biology↗