Cisneros, B. | bioRxiv Science

bioRxiv2023

Paneth and Paneth-like cells undergoing necroptosis fuel intestinal epithelial cell proliferation following IFN-γ stimulation.

The quality of life in patients with inflammatory bowel diseases (IBD) is strongly impaired. Alterations of intestinal epithelial homeostasis contribute to the development and establishment of IBD. Intestinal Paneth and Paneth-like cells produce and secrete luminal proteins sustaining epithelial homeostasis. Here we show that IFN-{gamma} stimulates Paneth and Paneth-like cells degranulation that triggers the proliferation of intestinal epithelial cells (IEC) in a Wnt/{beta}-catenin independent manner. Degranulation in Paneth and Paneth-like cells was mTORC1 and necroptosis dependent. Remarkably, lack of IFN-{gamma}, inhibition of mTORC1, or impeding necroptosis reduces IEC proliferation cytokine-mediated. Our findings identify a new role for IFN-{gamma} in stimulating IEC proliferation through inducing degranulation of Paneth and Paneth-like cells which is mTORC1 and necroptosis- dependent. In a mouse model of colitis, mTORC1 activation and necroptosis regulate Paneth and Paneth-like cell secretion. Furthermore, the colitogenic environment triggers PC metaplasia in the distal region of the large intestine to simulate cell proliferation. HighlightsIFN-{gamma} stimulates proliferation, {beta}-catenin independent. IFN-{gamma} enhances mitochondrial activity and proliferation IFN-{gamma} regulates PC biogenesis. mTORC1-dependent necroptosis mediates secretion in Paneth and Paneth-like cells.

physiology↗

bioRxiv2020

Heterologous expression of methylxanthine synthesis enzymes in mammalian cells and their use as reporter proteins

This work demonstrates the reconstitution of active methylxanthine synthesis enzymes in human cells and their potential use as inducible reporter enzymes. A variety of plant enzymes involved in caffeine synthesis have been characterized in vitro and several of these methylxanthine synthesis enzymes have been heterologously-expressed in yeast or bacteria. In this work, enzymes from Coffea arabica, Camellia sinensis, and Paullinia cupana have been heterologously-expressed in human cells. We demonstrate that the enzymes tested exhibit similar patterns of activity with a set of xanthine substrates in human cells when compared to previous reports of in vitro activity. We demonstrate that the activity of these enzymes can be used as a reporter for juxtacrine signaling using synNotch-induced expression in the presence of an appropriate substrate. When used in combination with synthetic caffeine receptors, this work has potential for use as an in vivo reporter (e.g. enabling non-invasive monitoring of cell-cell interactions after a cellular transplant) or in synthetic intercellular signaling a methylxanthine, such as caffeine, acting as a synthetic paracrine hormone.

synthetic biology↗