Baba, R. | Search bioRxiv

bioRxiv2022

Quantitative live-cell imaging of secretion activity reveals dynamic immune responses

The measurement of cytokine secretions has contributed to the development of immunology; however, new methods that enable highly sensitive and efficient analysis are required for the precise characterisation of dynamic secretion activity when using rare cells or limited human specimens. Here, we report a new technology for quantitative live-cell imaging of secretion activity (qLCI-S), that enables high-throughput and dual-colour detection of prolonged secretion activity at the single-cell level, followed by transcriptome analysis for individual cells based on their phenotype. The power of the qLCI-S was demonstrated by visualising the individual and longitudinal cytokine secretion patterns of group 2 innate lymphoid cells, which comprised <0.01% human peripheral blood mononuclear cells, and identifying their minor subpopulations. This new technology will provide new insights into the spatiotemporal dynamic nature of various secretory functions and the development of fundamental tools for phenotypic drug discovery and regenerative and precision medicine.

biophysics↗

bioRxiv2020

Inhibition of KDM1A activity restores adult neurogenesis and improves hippocampal memory in a mouse model of Kabuki syndrome

Kabuki syndrome (KS) is a rare cause of intellectual disability primarily caused by loss of function mutations in lysine-specific methyltransferase 2D (KMT2D), which normally adds methyl marks to lysine 4 on histone 3. Previous studies have shown that a mouse model of KS (Kmt2d+/{beta}Geo) demonstrates disruption of adult neurogenesis and hippocampal memory. Proof-of-principle studies have shown postnatal rescue of neurological dysfunction following treatments that promote chromatin opening, however, these strategies are non-specific and do not directly address the primary defect of histone methylation. Since lysine-specific demethylase 1A (LSD1/KDM1A) normally removes the H3K4 methyl marks added by KMT2D, we hypothesize that inhibition of KDM1A demethylase activity may ameliorate molecular and phenotypic defects stemming from KMT2D loss. To test this hypothesis, we evaluated a recently developed KDM1A inhibitor (TAK-418) in Kmt2d+/{beta}Geo mice. We find that orally administered TAK-418 increases the numbers of newly born Doublecortin (DCX)+ cells and processes in hippocampus in a dose dependent manner. We also observe TAK-418-dependent rescue of histone modification defects in hippocampus both by Western blot and ChIP-Seq. Treatment rescues gene expression abnormalities including those of immediate early genes such as FBJ osteosarcoma oncogene (Fos) and FBJ osteosarcoma oncogene homolog B (Fosb). After 2 weeks of TAK-418, Kmt2d+/{beta}Geo mice demonstrate normalization of hippocampal memory defects. In summary, our data suggest that KDM1A inhibition is a plausible treatment strategy for KS and support the hypothesis that the epigenetic dysregulation secondary to KMT2D dysfunction plays a major role in the postnatal neurological disease phenotype in KS.

genetics↗