Gieniec, K. A. | Search bioRxiv

bioRxiv2026

Macrophage calcium signaling dynamics revealed using genetically-encoded sensors

Macrophages (M{Phi}s) inhabit all mammalian organs, adapting to and influencing the tissues in which they reside. These versatile cells rapidly respond to tissue-specific signals, clean up debris and serve as the first line of defense against pathogens. Their ability to act quickly relates to their abundance and specific arrangement in tissues, as well as the systems they possess for detecting, processing and integrating emergent signals. Ca2+ is a fast second messenger that has been linked to many of the core functions of M{Phi}s. However, spatiotemporal features of physiologically-relevant Ca2+ signals in M{Phi}s remain largely uncharacterized. Using mouse models expressing genetic biosensors and fluorescently tagged channels, we visualize M{Phi} Ca2+ signal dynamics and heterogeneity, uncover a remarkable degree of mechanosensitivity in these cells, and characterize the physiological consequences of genetic ablation of Piezo1 channels via analysis of knockout models across their lifetime. Our in-depth investigation of M{Phi} Ca2+ signaling dynamics has broad relevance for the field of M{Phi} biology and the tissues that these cells support.

immunology↗

bioRxiv2020

The BMP antagonist Gremlin1 contributes to the development of cortical excitatory neurons, motor balance and fear responses

Bone morphogenetic protein (BMP) signaling is required for early forebrain development and cortical formation. How the endogenous modulators of BMP signaling regulate the structural and functional maturation of the developing brain remains unclear. Here we show that expression of the BMP antagonist, Grem1, marks a neuroprogenitor that gives rise to layer V and VI glutamatergic neurons in the embryonic mouse brain. Lineage tracing of Grem1-expressing cells in the embryonic brain was examined by administration of tamoxifen to pregnant Grem1creERT Rosa26LSLTdtomato mice at 13.5 days post coitum (dpc), followed by collection of embryos later in gestation. In addition, at 14.5 dpc, bulk mRNA seq analysis of differentially expressed transcripts between FACS sorted Grem1 positive and negative cells was performed. We also generated Emx1-cre mediated Grem1 conditional knockout mice (Emx1-Cre;Grem1flox/flox) in which the Grem1 gene was deleted specifically in the dorsal telencephalon. Grem1Emx1cKO animals had reduced cortical thickness, especially layers V and VI and impaired motor balance and fear sensitivity compared to littermate controls. This study has revealed new roles for Grem1 in the structural and functional maturation of the developing cortex. Summary statementThe BMP antagonist, Grem1, marks neuroprogenitors that give rise to deep layer glutamatergic neurons in the embryonic mouse brain. Grem1 conditional knockout mice display cortical and behavioural abnormalities.

developmental biology↗