Evidence that TRPC1 contributes to calcium-induced differentiation of human keratinocytes. Pflugers Arch
ABSTRACT External calcium ion concentration is a major regulator of epidermal keratinocyte differentiation in vitro and probably also in vivo. Regulation of calcium-induced differentiation changes is proposed to occur via an external calcium-sensing, signaling pathway that utilizes increases in intracellular calcium ion concentration to activate differentiation-related gene expression. Calcium ion release from intracellular stores and calcium ion influx via store-operated calcium-permeable channels are key elements in this proposed signaling pathway; however, the channels involved have not yet been identified. The present report shows that human gingival keratinocytes (HGKs) also undergo calcium-induced differentiation in vitro as indicated by involucrin expression and morphological changes. Moreover, TRPC1, which functions as a store-operated calcium channel in a number of cell types, including epidermal keratinocytes, is expressed in both proliferating and differentiating HGKs. Transfection of HGKs with TRPC1 siRNA disrupted expression of TRPC1 mRNA and protein compared with transfection with scrambled TRPC1 siRNA. Cells with disrupted TRPC1 expression showed decreased calcium-induced differentiation as measured by involucrin expression or morphological changes, as well as decreased thapsigargin-induced calcium ion influx, and a decreased rate of store calcium release. These results indicate that TRPC1 is involved in calcium-induced differentiation of HGKs likely by supporting a store-operated calcium ion influx.
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- "On the right (in red) is a list of cell or whole tissue/body effects that have been suggested to be driven or potentiated by TRPC activity; in other words, if TRPC channels were to be inhibited, the opposite of the effect is predicted to occur (e.g. less pancreatitis). Example references for cell expression items: acinar gland cells (Liu et al., 2007); adipocytes (Sukumar et al., 2012); astrocytes (Shirakawa et al., 2010); cardiac myocytes (Eder and Molkentin, 2011); cochlea hair cells (Quick et al., 2012); endothelial cells (Ahmmed et al., 2004); epithelial cells (Kim et al., 2011); fibroblasts (Xu et al., 2008); hepatocytes (Rychkov and Barritt, 2011); keratinocytes (Cai et al., 2006); leukocytes (Yildirim et al., 2012); mast cells (Freichel et al., 2012); mesangial cells (Sours et al., 2006); neurones (Bollimuntha et al., 2011); osteoclasts/blasts (Abed et al., 2009); platelets (Ramanathan et al., 2012); podocytes (Dryer and Reiser, 2010); skeletal muscle (Gervasio et al., 2008); smooth muscle cells (Beech et al., 2004); and tumour cells (Thebault et al., 2006). Example references for effect items: angiogenesis (Yu et al., 2010); cancer cell drug resistance (Ma et al., 2012); cell adhesion (Smedlund et al., 2010); cell migration (Xu et al., 2006); cell proliferation (Sweeney et al., 2002); cell survival (Selvaraj et al., 2012); cell turning (Wang and Poo, 2005); efferocytosis (Tano et al., 2011); gastrointestinal motility (Tsvilovskyy et al., 2009); glomerular filtration (Dryer and Reiser, 2010); hypoadiponectinaemia (Sukumar et al., 2012); hypo-matrix metalloproteinase (Xu et al., 2008); hypertrophy (cardiac) (Eder and Molkentin, 2011); innate fear (Riccio et al., 2009); lung hyper-responsiveness (Yildirim et al., 2012); mast cell degranulation (Ma et al., 2008); motor coordination (Trebak, 2010); muscle endurance (Zanou et al., 2010); neointimal hyperplasia (Kumar et al., 2006); oedema (Weissmann et al., 2012); permeability (Tiruppathi et al., 2002); pancreatitis (Kim et al., 2011); saliva secretion (Liu et al., 2007); seizure (Phelan et al., 2013); survival after MI (myocardial infarction) (Jung et al., 2011); thrombosis (Ramanathan et al., 2012); vaso-modulation (e.g. "
ABSTRACT: The primary purpose of this review is to address the progress towards small molecule modulators of human Transient Receptor Potential Canonical proteins (TRPC1, TRPC3, TRPC4, TRPC5, TRPC6 and TRPC7). These proteins generate channels for calcium and sodium ion entry. They are relevant to many mammalian cell types including acinar gland cells, adipocytes, astrocytes, cardiac myocytes, cochlea hair cells, endothelial cells, epithelial cells, fibroblasts, hepatocytes, keratinocytes, leukocytes, mast cells, mesangial cells, neurones, osteoblasts, osteoclasts, platelets, podocytes, smooth muscle cells, skeletal muscle, and tumour cells. There are broad-ranging positive roles of the channels in cell adhesion, migration, proliferation, survival and turning, vascular permeability, hypertrophy, wound-healing, hypo-adiponectinaemia, angiogenesis, neointimal hyperplasia, oedema, thrombosis, muscle endurance, lung hyper-responsiveness, glomerular filtration, gastrointestinal motility, pancreatitis, seizure, innate fear, motor coordination, saliva secretion, mast cell degranulation, cancer cell drug resistance, survival after myocardial infarction, efferocytosis, hypo-matrix metalloproteinase, vasoconstriction and vasodilatation. Known small molecule stimulators of the channels include hyperforin, genistein and rosiglitazone, but there is more progress with inhibitors, some of which have promising potency and selectivity. The inhibitors include 2-aminoethoxydiphenyl borate, 2-aminoquinolines, 2-aminothiazoles, fatty acids, isothiourea derivatives, naphthalene sulphonamides, N-phenylanthranilic acids, phenylethylimidazoles, piperazine/piperidine analogues, polyphenols, pyrazoles, and steroids. A few of these agents are starting to be useful as tools for determining the physiological and pathophysiological functions of TRPC channels. We suggest that the pursuit of small molecule modulators for TRPC channels is important but that it requires substantial additional effort and investment before we can reap the rewards of highly potent and selective pharmacological modulators.British Journal of Pharmacology 06/2013; 170(3). DOI:10.1111/bph.12274 · 4.99 Impact Factor
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- "To explore if abnormalities in TRPC expression can also be demonstrated in non-lesional and lesional skin obtained from psoriasis patients using immunohistochemistry, we analyzed exemplary the expression of the TRPC1-, TRPC4-and TRPC6-channels which are known to be important players in CaR induced Ca 2+ influx (Cai et al. 2006; Fatherazi et al., 2007; Müller et al., 2008). TRPC1 was mainly expressed in stratum basale of the epidermis in skin biopsies from healthy controls and, to a somewhat lesser extent in lesional and lesional psoriatic skin (Fig. 3). "
ABSTRACT: Psoriasis is a characteristic inflammatory and scaly skin condition with typical histopathological features including increased proliferation and hampered differentiation of keratinocytes. The activation of innate and adaptive inflammatory cellular immune responses is considered to be the main trigger factor of the epidermal changes in psoriatic skin. However, the molecular players that are involved in enhanced proliferation and impaired differentiation of psoriatic keratinocytes are only partly understood. One important factor that regulates differentiation on the cellular level is Ca(2+). In normal epidermis, a Ca(2+) gradient exists that is disturbed in psoriatic plaques, favoring impaired keratinocyte proliferation. Several TRPC channels such as TRPC1, TRPC4, or TRPC6 are key proteins in the regulation of high [Ca(2+)](ex) induced differentiation. Here, we investigated if TRPC channel function is impaired in psoriasis using calcium imaging, RT-PCR, western blot analysis and immunohistochemical staining of skin biopsies. We demonstrated substantial defects in Ca(2+) influx in psoriatic keratinocytes in response to high extracellular Ca(2+) levels, associated with a downregulation of all TRPC channels investigated, including TRPC6 channels. As TRPC6 channel activation can partially overcome this Ca(2+) entry defect, specific TRPC channel activators may be potential new drug candidates for the topical treatment of psoriasis.PLoS ONE 02/2011; 6(2):e14716. DOI:10.1371/journal.pone.0014716 · 3.53 Impact Factor
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- "Keratinocytes cultured in low-calcium conditions (low calcium, 0.3 mM in K-SFM) prior to the addition of C. albicans appeared to be in the process of transitioning between the undifferentiated and early differentiated states. Keratin 19, a marker of undifferentiated keratinocytes (Larouche et al., 2005), and involucrin that is expressed in cells at an early stage of differentiation (Cai et al., 2006), were very prominent in the perinuclear region of the cell (Fig. 4A and 0 h, images 1 and 7; Fig. 4B and C), whereas levels of the late differentiation markers, SPRR3 and keratin 13, were low as expected for keratinocytes in the early stages of differentiation (Fig. 4A and 0 h, images 13 and 19; Fig. 4D and E). "
ABSTRACT: A hallmark of the mucosa of immunocompromized hosts in oral candidiasis is a hyperkeratinized region heavily colonized with fungi at the surface of the terminally differentiated epithelium. To gain insight into the processes important for promoting mucosal invasion by fungi, we characterized the response of keratinocytes to the presence of Candida albicans. Indirect immunofluorescence and kymographic analyses revealed a multifaceted keratinocyte response of OKF6/TERT-2 cells to C. albicans that consisted of: cytoskeletal reorganization within 3 h, motility and cell expansion with formation of E-cadherin-mediated cell-cell adhesions within 6 h, increased expression of late differentiation markers and decreased expression of calprotectin. The initial expansive phase was followed by dissolution of cell-cell adhesions and a decrease in cell size accompanied by loss of E-cadherin. The keratinocyte response depended on soluble factors associated with hyphal growth as demonstrated using the efg1Delta/efg1Delta, cap1Delta/cap1Delta, als3Delta/als3Delta, hwp1Delta/hwp1Deltaand sap4-6Delta/sap4-6Delta mutants and was not observed in the presence of the non-pathogenic yeast, Saccharomyces cerevisiae. These studies show the potential for C. albicans to manipulate the stratified epithelial cells to a state of differentiation that is more permissive of fungal colonization of oral tissue, which is likely to play an important role in the pathogenesis of candidiasis.Cellular Microbiology 03/2009; 11(6):946-66. DOI:10.1111/j.1462-5822.2009.01303.x · 4.82 Impact Factor