Gastrointestinal (GI) enterochromaffin (EC) cells are specialised sensors of luminal stimuli. They secrete most of the body's serotonin (5-HT), and are critical for modulating GI motility, secretion, Show more
Gastrointestinal (GI) enterochromaffin (EC) cells are specialised sensors of luminal stimuli. They secrete most of the body's serotonin (5-HT), and are critical for modulating GI motility, secretion, and sensation, while also signaling satiety and intestinal discomfort. The aim of this study was to investigate mechanisms underlying the regulation of human EC cells, and the relative importance of direct nutrient stimulation compared with neuronal and paracrine regulation. Intestinal organoids from human duodenal biopsies were modified using CRISPR-Cas9 to specifically label EC cells with either the fluorescent protein Venus or the cyclic adenosine monophosphate (cAMP) sensor Epac1-S-H187. EC cells were purified by fluorescence-activated cell sorting for analysis by bulk RNA sequencing and liquid chromatography mass spectrometry peptidomics. The function of human EC cells was studied using single-cell patch clamp, calcium and cAMP imaging, and 5-hydroxytryptamine (5-HT) enzyme-linked immunosorbent assays (ELISAs). Human EC cells showed expression of receptors for nutrients (including GPR142, GPBAR1, GPR119, FFAR2, OR51E1, OR51E2), gut hormones (including SSTR1,2&5, NPY1R, GIPR) and neurotransmitters (ADRA2A, ADRB1). Functional assays revealed EC responses (calcium, cAMP, and/or secretion) to a range of stimuli, including bacterial metabolites, aromatic amino acids, and adrenergic agonists. Electrophysiological recordings showed that isovalerate increased action potential firing. 5-HT release from EC cells controls many physiological functions and is currently being targeted to treat disorders of the gut-brain axis. Studying ECs from human organoids enables improved understanding of the molecular mechanisms underlying EC cell activation, which is fundamental for the development of new strategies to target 5-HT-related gut and metabolic disorders. Show less
This study investigates how sorafenib induces toxicity in glomerular cells and examines the protective role of 8,9-epoxyeicosatrienoic acid (8,9-EET) analogs in reducing this kidney damage. Human rena Show more
This study investigates how sorafenib induces toxicity in glomerular cells and examines the protective role of 8,9-epoxyeicosatrienoic acid (8,9-EET) analogs in reducing this kidney damage. Human renal mesangial cells (HRMCs) and podocytes were treated with no treatment, sorafenib alone, or sorafenib combined with 8,9-EET analogs. Cell viability and apoptosis were measured in both cell types. Sorafenib (1-10 µM) lowered cell viability and increased caspase 3/7 activity in a dose-dependent way in HRMCs and podocytes. Five of twenty 8,9-EET analogs significantly enhanced cell survival and decreased apoptosis. RNA sequencing showed that sorafenib altered 1244 genes, including those involved in cell cycle and the Raf/MEK/ERK pathway. The 8,9-EET analog MDB-52a raised ANGPTL4 levels, linked to metabolism and vascular health, and reduced ACTA2, which could activate protective pathways. Nephroseq data correlated these gene changes with glomerulosclerosis. MDB-52 appears to counteract gene disruptions and protect against sorafenib-induced kidney damage. Overall, 8,9-EET analogs targeting glomerular cells could be potential therapeutic agents to lessen sorafenib-related nephrotoxicity. Show less