Biology subjects

Eriksson, E. M.

Publications and source records attributed to Eriksson, E. M..

3 recordsLinked to original sources

bioRxiv2025

TRPV4 Promotes Histamine Receptor Signaling in Lymphatic Endothelial Cells

BackgroundThe control of lymphatic permeability and flow is essential for homeostatic regulation of tissue fluid balance and immune responses. Histamine has been identified as an important signaling mediator involved in the regulation of lymphatic function. Histamine is released from activated perilymphatic mast cells and may also be produced by lymphatic endothelial cells (LECs) in response to flow-induced shear stress. The non-selective cation channel Transient Receptor Potential Vanilloid 4 (TRPV4) is an important mediator of signaling by GPCRs, including histamine receptors. TRPV4 is activated in response to shear stress and is functionally expressed by LECs. We hypothesized that histamine receptors and TRPV4 interact in LECs, leading to activation of distinct downstream signaling pathways. This study examined the mechanistic link between TRPV4 activity and histaminergic signaling in LECs. Principle ResultsHistaminergic Ca2+ signaling was examined in primary human LECs. Responses to histamine were mainly driven by the H1R histamine receptor, with some contribution by the H4R subtype, as determined using selective antagonists. H4R signaling in response to 4-methylhistamine was effectively prevented by either removal of extracellular Ca2+ or block of TRPV4 activity, consistent with TRPV4-dependence. Conversely, activation of H4R resulted in marked sensitization of subsequent responses to the selective TRPV4 agonist GSK1016790A. This interaction was mediated through a PLA2-dependent mechanism. TRPV4 activity was required for histamine receptor-evoked translocation of the Ca2+-dependent transcription factor NFATc1 and for cytoskeletal remodeling. By contrast, the release of cytokines in response to activation of either histamine receptors or TRPV4 were largely independent processes. ConclusionsThis study identifies TRPV4 as an important mediator of histaminergic signaling in LECs. The findings provide further support for the involvement of TRPV4 in defining the nature and magnitude of endothelial signaling downstream of GPCRs. HighlightsO_LIHistamine receptors are functionally expressed by primary human LECs C_LIO_LITRPV4 is an important driver of H4R-evoked Ca2+ signaling in LECs C_LIO_LIHistamine receptor activation sensitizes TRPV4 signaling in LECs C_LIO_LITRPV4 promotes histamine-evoked NFATc1 translocation to the nucleus of LECs C_LIO_LIHistamine and TRPV4 evoked cytokine release from LECs involve distinct mechanisms C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/690563v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@409b49org.highwire.dtl.DTLVardef@192f58dorg.highwire.dtl.DTLVardef@136fdd0org.highwire.dtl.DTLVardef@15175c6_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract.C_FLOATNO Histamine exerts its effects on lymphatic endothelial cells through interaction with the H1R and H4R receptor subtypes. H1R activation promotes Ca2+ release from intracellular stores. Activation of the H4R leads to elevated intracellular Ca2+ through crosstalk with the non-selective cation channel TRPV4. Interaction between H4R and TRPV4 is mediated through a PLA2-dependent mechanism. TRPV4 enhances histamine-evoked NFATc1 activation and translocation and cytoskeletal remodeling. In contrast, histamine receptor- and TRPV4-mediated cytokine release appear to involve mechanistically independent processes. C_FIG

pharmacology and toxicology↗

bioRxiv2024

TRPV4 is expressed by enteric glia and muscularis macrophages of the colon but does not play a prominent role in colonic motility

BackgroundMechanosensation is an important trigger of physiological processes in the gastrointestinal tract. Aberrant responses to mechanical input are associated with digestive disorders, including visceral hypersensitivity. Transient Receptor Potential Vanilloid 4 (TRPV4) is a mechanosensory ion channel with proposed roles in visceral afferent signaling, intestinal inflammation, and gut motility. While TRPV4 is a potential therapeutic target for digestive disease, current mechanistic understanding of how TRPV4 may influence gut function is limited by inconsistent reports of TRPV4 expression and distribution. MethodsIn this study we profiled functional expression of TRPV4 using Ca2+ imaging of wholemount preparations of the mouse, monkey, and human intestine in combination with immunofluorescent labeling for established cellular markers. The involvement of TRPV4 in colonic motility was assessed in vitro using videomapping and contraction assays. ResultsThe TRPV4 agonist GSK1016790A evoked Ca2+ signaling in muscularis macrophages, enteric glia, and endothelial cells. TRPV4 specificity was confirmed using TRPV4 KO mouse tissue or antagonist pre-treatment. Calcium responses were not detected in other cell types required for neuromuscular signaling including enteric neurons, interstitial cells of Cajal, PDGFR+ cells, and intestinal smooth muscle. TRPV4 activation led to rapid Ca2+ responses by a subpopulation of glial cells, followed by sustained Ca2+ signaling throughout the enteric glial network. Propagation of these waves was suppressed by inhibition of gap junctions or Ca2+ release from intracellular stores. Coordinated glial signaling in response to GSK1016790A was also disrupted in acute TNBS colitis. The involvement of TRPV4 in the initiation and propagation of colonic motility patterns was examined in vitro. ConclusionsWe reveal a previously unappreciated role for TRPV4 in the initiation of distension-evoked colonic motility. These observations provide new insights into the functional role of TRPV4 activation in the gut, with important implications for how TRPV4 may influence critical processes including inflammatory signaling and motility. SummaryO_LITRPV4 is expressed by equivalent cell types in the rodent and primate (monkey and human) colon. This mechanosensitive ion channel has proposed roles in inflammation, visceral afferent signaling, and colonic motility. C_LIO_LINew analysis methods were developed to examine cellular communication in the enteric glial network. This approach revealed new insights into inflammation-associated changes in glial connectivity. C_LIO_LINew roles for TRPV4 in transduction of distension-evoked responses in the colon and colonic motility were identified. C_LI Key findingsWe have defined the cell types that functionally express TRPV4 in the gut wall. These include enteric glia, endothelia of blood and lymphatic vessels, mMac, and extrinsic afferent nerves. TRPV4- dependent Ca2+ signaling was not detected in enteric neurons, PDGFR cells, interstitial cells of Cajal and smooth muscle cells, which are important drivers of gut motility. These observations align with our experimental evidence for limited involvement of TRPV4 in neuromuscular transmission and propagating colonic motility. New and NoteworthyO_LINovel cellular sites of functional TRPV4 expression in the GI tract were identified and compared across multiple vertebrate species. New analytical approaches to characterize enteric glial communication in a spatiotemporal manner were developed. C_LIO_LIA supporting role for TRPV4 in the initiation of propagating colonic contractions in response to distension was demonstrated. Potential mechanisms that contribute to TRPV4-mediated effects on GI function were identified. C_LIO_LITRPV4-dependent activity in enteric glia is enhanced in inflammation, consistent with current evidence for inflammation-associated sensitization of TRPV4 on visceral afferents and a major role in mechanically evoked nociceptive signaling. C_LIO_LIPair correlation analysis was used to examine spatial connectivity of Ca2+ signaling, enabling demonstration of dysregulated glial communication in acute inflammation. C_LI

physiology↗

bioRxiv2020

Transcriptional memory-like imprints and enhanced functional activity in γδ T cells following resolution of malaria infection

{gamma}{delta} T cells play an essential role in the immune response to malaria infection. However, long-lasting effects of malaria infection on the {gamma}{delta} T cell population still remain inadequately understood. This study investigated transcriptional changes and memory-like functional capacity of malaria pre-exposed {gamma}{delta} T cells using a Plasmodium chabaudi infection model. We show that multiple genes associated with effector function (chemokines, cytokines and cytotoxicity) and antigen-presentation were upregulated in P. chabaudi-exposed {gamma}{delta} T cells compared to {gamma}{delta} T cells from naive mice. This transcriptional profile was positively correlated with profiles observed in conventional memory CD8+ T cells and was accompanied by enhanced reactivation upon secondary encounter with Plasmodium-infected red blood cells in vitro. Collectively our data demonstrate that Plasmodium exposure result in "memory-like imprints" in the {gamma}{delta} T cell population and also promotes {gamma}{delta} T cells that can support antigen-presentation during subsequent infections.

immunology↗