Cazareth, J. | Search bioRxiv

bioRxiv2020

Agonist-induced Functional Analysis and Cell Sorting, a novel tool to select and analyze neurons: Fragile X as a proof of concept.

To get a better insight into the dynamic interaction between cells and their environment, we developed the agonist-induced Functional Analysis and Cell Sorting (aiFACS) technique, which allows the simultaneous recording and sorting of cells in real-time according to their immediate and individual response to a stimulus. By modulating the aiFACS selection parameters, testing different developmental times, using various stimuli and multiplying the analysis of readouts, it is possible to analyze cell populations of any tissue, including tumors. The association of aiFACS to single-cell transcriptomic allows to build a tissue cartography based on specific functional response/s of cells. As proof of concept, we used aiFACS on the dissociated mouse brain, a highly heterogenous tissue, enriching it in interneurons upon stimulation with an agonist of the glutamate receptors and upon sorting based on calcium levels. Further single-cell RNA-seq of these aiFACS-selected interneurons resulted in a nine-cluster classification. Furthermore, we used aiFACS on interneurons derived from the brain of the Fmr1-KO mouse, a rodent model of Fragile X syndrome. We show here that these interneurons manifest a generalized defective pharmacological response compared to wild type, affecting all the analyzed cell clusters at one specific post-natal developmental time.

genomics↗

bioRxiv2019

An oomycete effector impairs autophagy in evolutionary distant organisms and favors host infection

An arsenal of effector proteins from plant pathogenic Phytophthora species manipulates their host from inside the cells. Phytophthora parasitica produces the effector AVH195 during an initial, biotrophic phase of infection. The protein transiently impairs plant immune-associated hypersensitive cell death in Nicotiana. ATG8 Interaction Motifs in the protein indicate that the effector targets the autophagic core machinery. We selected a photosynthetic microalga with a single copy ATG8 gene as an alternative model to dissect AVH195-induced autophagic perturbation. AVH195 slows down autophagic flux in Chlamydomonas reinhardtii thus promoting the accumulation of cargo-rich vesicles. In yeast, membrane-associated AVH195 interacts with ATG8 from Chlamydomonas and with different ATG8 isoforms from Arabidopsis thaliana. The overexpression of Avh195 in Arabidopsis promotes growth of both infecting P. parasitica and Hyaloperonospora arabidopsidis, an obligate biotroph. To our knowledge, this report provides first evidence that an oomycete effector non-selectively targets ATG8 in different organisms from the green lineage to slow down autophagic flux for infection.

plant biology↗