Chicken-derived RSPO1 and WNT3 contribute to maintaining longevity of chicken intestinal organoid cultures.

Intestinal organoids are advanced cellular models, which are widely used in mammalian studies to mimic and study in vivo intestinal function and host-pathogen interactions. Growth factors WNT3 and RSPO1 are crucial for the growth of intestinal organoids. Chicken intestinal organoids are currently cultured with mammalian Wnt3a and Rspo1, however, maintaining their longevity has shown to be challenging.

Flood Control: How Milk-Derived Extracellular Vesicles Can Help to Improve the Intestinal Barrier Function and Break the Gut-Joint Axis in Rheumatoid Arthritis.

Unlabelled: Many studies provided compelling evidence that extracellular vesicles (EVs) are involved in the regulation of the immune response, acting as both enhancers and dampeners of the immune system, depending on the source and type of vesicle. Research, including ours, has shown anti-inflammatory effects of milk-derived EVs, using human breast milk as well as bovine colostrum and store-bought pasteurized cow milk, in systems as well as therapeutically in animal models. Although it is not completely elucidated which proteins and miRNAs within the milk-derived EVs contribute to these immunosuppressive capacities, one proposed mechanism of action of the EVs is the modulation of the crosstalk between the (intestinal) microbiome and their host health.

Enterocytes, fibroblasts and myeloid cells synergize in anti-bacterial and anti-viral pathways with IL22 as the central cytokine.

IL22 is an important cytokine involved in the intestinal defense mechanisms against microbiome. By using ileum-derived organoids, we show that the expression of anti-microbial peptides (AMPs) and anti-viral peptides (AVPs) can be induced by IL22. In addition, we identified a bacterial and a viral route, both leading to IL22 production by T cells, but via different pathways.

Survival and cellular heterogeneity of epithelium in cultured mouse and rat precision-cut intestinal slices.

Precision-cut intestinal slices (PCIS) are used to study intestinal (patho)physiology, drug efficacy, toxicity, transport and metabolism ex vivo. One of the factors that limit the use of PCIS is a relatively short life-span. Moreover, culture-induced changes in cellular composition of PCIS remain largely uncharacterized.

Type 2 diabetes-related proteins derived from an in vitro model of inflamed fat tissue.

Currently, there is a worldwide increase of patients with type 2 diabetes (T2D). During the progression of healthy obese to T2D status, there is an influx of immune cells, in particular macrophages, into visceral adipose tissue, accompanied by an increase of inflammatory cytokines, such as, IL6, TNFα and Hp. To get a better insight in the underlying mechanisms, we performed a quantitative LCMS analysis on a modified in vitro assay, combining 3T3L1 adipocytes and activated RAW264.

N-Docosahexaenoyl Dopamine, an Endocannabinoid-like Conjugate of Dopamine and the n-3 Fatty Acid Docosahexaenoic Acid, Attenuates Lipopolysaccharide-Induced Activation of Microglia and Macrophages via COX-2.

Several studies indicate that the n-3 long-chain polyunsaturated fatty acid docosahexaenoic acid (DHA) contributes to an attenuated inflammatory status in the development of neurodegenerative disorders, such as Alzheimer's and Parkinson's disease. To explain these effects, different mechanisms are being proposed, including those involving endocannabinoids and related signaling molecules. Many of these compounds belong to the fatty acid amides, conjugates of fatty acids with biogenic amines.

The Noncaloric Sweetener Rebaudioside A Stimulates Glucagon-Like Peptide 1 Release and Increases Enteroendocrine Cell Numbers in 2-Dimensional Mouse Organoids Derived from Different Locations of the Intestine.

Background: Glucagon-like peptide 1 (GLP-1) contributes to satiety and plays a pivotal role in insulin secretion and glucose homeostasis. Similar to GLP-1, peptide YY (PYY) and cholecystokinin also influence food intake. The secretion of these hormones by enteroendocrine cells along the intestine is modulated by nutrients.

Docosahexaenoyl serotonin, an endogenously formed n-3 fatty acid-serotonin conjugate has anti-inflammatory properties by attenuating IL-23-IL-17 signaling in macrophages.

Conjugates of fatty acids and amines, including endocannabinoids, are known to play important roles as endogenous signaling molecules. Among these, the ethanolamine conjugate of the n-3 poly unsaturated long chain fatty acid (PUFA) docosahexaenoic acid (22:6n-3) (DHA) was shown to possess strong anti-inflammatory properties. Previously, we identified the serotonin conjugate of DHA, docosahexaenoyl serotonin (DHA-5-HT), in intestinal tissues and showed that its levels are markedly influenced by intake of n-3 PUFAs.

Rap2A links intestinal cell polarity to brush border formation.

The microvillus brush border at the apex of the highly polarized enterocyte allows the regulated uptake of nutrients from the intestinal lumen. Here, we identify the small G protein Rap2A as a molecular link that couples the formation of microvilli directly to the preceding cell polarization. Establishment of apicobasal polarity, which can be triggered by the kinase LKB1 in single, isolated colon cells, results in enrichment of PtdIns(4,5)P(2) at the apical membrane.

Rac controls PIP5K localisation and PtdIns(4,5)P₂ synthesis, which modulates vinculin localisation and neurite dynamics.

In N1E-115 cells, neurite retraction induced by neurite remodelling factors such as lysophosphatidic acid, sphingosine 1-phosphate and semaphorin 3A require the activity of phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks). PIP5Ks synthesise the phosphoinositide lipid second messenger phosphatidylinositol(4,5)bisphosphate [PtdIns(4,5)P₂], and overexpression of active PIP5K is sufficient to induce neurite retraction in both N1E-115 cells and cerebellar granule neurones. However, how PIP5Ks are regulated or how they induce neurite retraction is not well defined.

A Rac1 inhibitory peptide suppresses antibody production and paw swelling in the murine collagen-induced arthritis model of rheumatoid arthritis.

Introduction: The Rho family GTPase Rac1 regulates cytoskeletal rearrangements crucial for the recruitment, extravasation and activation of leukocytes at sites of inflammation. Rac1 signaling also promotes the activation and survival of lymphocytes and osteoclasts. Therefore, we assessed the ability of a cell-permeable Rac1 carboxy-terminal inhibitory peptide to modulate disease in mice with collagen-induced arthritis (CIA).

LKB1 and AMPK family signaling: the intimate link between cell polarity and energy metabolism.

Research on the LKB1 tumor suppressor protein mutated in cancer-prone Peutz-Jeghers patients has continued at a feverish pace following exciting developments linking energy metabolism and cancer development. This review summarizes the current state of research on the LKB1 tumor suppressor. The weight of the evidence currently indicates an evolutionary conserved role for the protein in the regulation of various aspects of cellular polarity and energy metabolism.

Mst4 and Ezrin induce brush borders downstream of the Lkb1/Strad/Mo25 polarization complex.

The human Lkb1 kinase, encoded by the ortholog of the invertebrate Par4 polarity gene, is mutated in Peutz-Jeghers cancer syndrome. Lkb1 activity requires complex formation with the pseudokinase Strad and the adaptor protein Mo25. The complex can induce complete polarization in a single isolated intestinal epithelial cell.

Rac1-induced cell migration requires membrane recruitment of the nuclear oncogene SET.

The Rho GTPase Rac1 controls cell adhesion and motility. The effector loop of Rac1 mediates interactions with downstream effectors, whereas its C-terminus binds the exchange factor beta-Pix, which mediates Rac1 targeting and activation. Here, we report that Rac1, through its C-terminus, also binds the nuclear oncogene SET/I2PP2A, an inhibitor of the serine/threonine phosphatase PP2A.

Targeting and localized signalling by small GTPases.

Polarized cellular responses, for example, cell migration, require the co-ordinated assembly of signalling complexes at a particular subcellular location, such as the leading edge of cells. Small GTPases of the Ras superfamily play central roles in many (polarized) responses to growth factors, chemokines or integrin ligands. These small GTPases are functionally distinct, yet remarkably homologous in their primary sequence and especially in their effector domains.

Interaction between Tiam1 and the Arp2/3 complex links activation of Rac to actin polymerization.

The Rac-specific GEF (guanine-nucleotide exchange factor) Tiam1 (T-lymphoma invasion and metastasis 1) regulates migration, cell-matrix and cell-cell adhesion by modulating the actin cytoskeleton through the GTPase, Rac1. Using yeast two-hybrid screening and biochemical assays, we found that Tiam1 interacts with the p21-Arc [Arp (actin-related protein) complex] subunit of the Arp2/3 complex. Association occurred through the N-terminal pleckstrin homology domain and the adjacent coiled-coil region of Tiam1.

Targeting and activation of Rac1 are mediated by the exchange factor beta-Pix.

Rho guanosine triphosphatases (GTPases) are critical regulators of cytoskeletal dynamics and control complex functions such as cell adhesion, spreading, migration, and cell division. It is generally accepted that localized GTPase activation is required for the proper initiation of downstream signaling events, although the molecular mechanisms that control targeting of Rho GTPases are unknown. In this study, we show that the Rho GTPase Rac1, via a proline stretch in its COOH terminus, binds directly to the SH3 domain of the Cdc42/Rac activator beta-Pix (p21-activated kinase [Pak]-interacting exchange factor).

Small GTP-binding protein Ral is involved in cAMP-mediated release of von Willebrand factor from endothelial cells.

Objective: von Willebrand factor (vWF) is synthesized by endothelial cells and stored in specialized vesicles called Weibel-Palade bodies (WPBs). Recently, we have shown that the small GTP-binding protein Ral is involved in thrombin-induced exocytosis of WPBs. In addition to Ca2+-elevating secretagogues such as histamine and thrombin, release of WPB is also observed after administration of cAMP-raising substances such as epinephrine and vasopressin.

Calcium signaling regulates translocation and activation of Rac.

Rac is activated in response to various stimuli including growth factors and by adhesion to the extracellular matrix. However, how these stimuli ultimately result in Rac activation is poorly understood. The increase in intracellular calcium [Ca2+]i represents a ubiquitous second messenger system in cells, linking receptor activation to downstream signaling pathways.

The C-terminal domain of Rac1 contains two motifs that control targeting and signaling specificity.

Rho-like GTPases control a wide range of cellular functions such as integrin- and cadherin-mediated adhesion, cell motility, and gene expression. The hypervariable C-terminal domain of these GTPases has been implicated in membrane association and effector binding. We found that cell-permeable peptides, encoding the C termini of Rac1, Rac2, RhoA, and Cdc42, interfere with GTPase signaling in a specific fashion in a variety of cellular models.

VCAM-1-mediated Rac signaling controls endothelial cell-cell contacts and leukocyte transmigration.

Leukocyte adhesion is mediated totally and transendothelial migration partially by heterotypic interactions between the beta1- and beta2-integrins on the leukocytes and their ligands, Ig-like cell adhesion molecules (Ig-CAM), VCAM-1, and ICAM-1, on the endothelium. Both integrins and Ig-CAMs are known to have signaling capacities. In this study we analyzed the role of VCAM-1-mediated signaling in the control of endothelial cell-cell adhesion and leukocyte transendothelial migration.

Reactive oxygen species mediate Rac-induced loss of cell-cell adhesion in primary human endothelial cells.

The integrity of the endothelium is dependent on cell-cell adhesion, which is mediated by vascular-endothelial (VE)-cadherin. Proper VE-cadherin-mediated homotypic adhesion is, in turn, dependent on the connection between VE-cadherin and the cortical actin cytoskeleton. Rho-like small GTPases are key molecular switches that control cytoskeletal dynamics and cadherin function in epithelial as well as endothelial cells.