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Brasseale, K.

Publications and source records attributed to Brasseale, K..

2 recordsLinked to original sources

Spatiotemporal precise optical manipulation of intracellular molecular activities

Controlling chemical processes in live cells is a challenging task. The spatial heterogeneity of biochemical reactions in cells is often overlooked by conventional means of incubating cells with desired chemicals. A comprehensive understanding of spatially diverse biochemical processes requires precise control over molecular activities at the subcellular level. Herein, we develop a closed-loop optoelectronic control system that allows the manipulation of biomolecular activities in live cells at high spatiotemporal precision. Chemical-selective fluorescence signals are utilized to command lasers that trigger specific chemical reactions or control the activation of photoswitchable inhibitors at desired targets. We demonstrate the capability to selectively produce reactive oxygen species (ROS) solely at targeted organelles using blue light. Notably, the induction of ROS in the endoplasmic reticulum leads to a more pronounced disruption of tubulin polymerization and a reduction in green fluorescent protein signals, in comparison to that in lipid droplets. Moreover, when combined with a photoswitchable inhibitor, we selectively inhibit tubulin polymerization within subcellular compartments. This technology enables spatiotemporal control over chemical processes and drug activities, exclusively at desired targets, while minimizing undesired effects on non-targeted locations.

cell biology↗

Inducible overexpression of zebrafish microRNA-722 suppresses chemotaxis of human neutrophil like cells

Neutrophil migration is essential for battling against infections but also drives chronic inflammation. Since primary neutrophils are terminally differentiated and not genetically tractable, leukemia cells such as HL-60 are differentiated into neutrophil-like cells to study mechanisms underlying neutrophil migration. However, constitutive overexpression or inhibition in this cell line does not allow the characterization of the genes that affect the differentiation process. Here we apply the tet-on system to induce the expression of zebrafish miR-722 in differentiated HL-60. Overexpression of miR-722 reduced the mRNA level of genes in the chemotaxis and inflammation pathways, including RAC2. Consistently, cell migration is significantly inhibited upon induced miR-722 overexpression. Together, miR-722 is an evolutionarily conserved suppressor for neutrophil migration and signaling in zebrafish and human.

immunology↗