Project description:Lacritin targets its coreceptor 'syndecan-1' in lacritin-dependent production of the important dry eye mucin 'MUC16'. Real-time PCR analysis suggests that this effect is post-transcriptional. In contrast, serum stimulation of MUC16 by these cells is transcriptionally dependent. Our goal is to determine whether this regulation is global to other heavily O-glycosylated proteins, and if so, if it is dependent on transcription of a Golgi glycosyltransferases. If not, the mechanism might be microRNA dependent.
Project description:Lacritin targets its coreceptor 'syndecan-1' in lacritin-dependent production of the important dry eye mucin 'MUC16'. Real-time PCR analysis suggests that this effect is post-transcriptional. In contrast, serum stimulation of MUC16 by these cells is transcriptionally dependent. Our goal is to determine whether this regulation is global to other heavily O-glycosylated proteins, and if so, if it is dependent on transcription of a Golgi glycosyltransferases. If not, the mechanism might be microRNA dependent. Among other glycogenes, expression of heparanases, sulfotransferases and epimerase are also of interest. Heparanase is required for lacritin binding to its co-receptor syndecan-1 and this binding site may require a sulfated iduronic acid. In request 1705, we recently asked core D whether they could generate this sulfate iduronic acid-containing glycan (iduronic acid (2-O-sulfated)-N-acetylglucosamine-glucuronic acid-N-acetylglucosamine-[glucuronic acid-N-acetylglucosamine]5-glucuronic acid-galactose-galactose-SERINE) to test as a competitive inhibitor in binding studies. Our experiment is to compare Glyco-gene expression by human corneal epithelial cells in response to cell communication glycoprotein 'lacritin' versus negative control deletion construct 'C-25 lacritin' and versus positive control serum.
Project description:Purpose. How vitamin A contributes to the maintenance of the wet-surfaced phenotype at the ocular surface is not well understood. We sought to identify vitamin A responsive genes in ocular surface epithelia using gene microarray analysis of cultures of a human conjunctival epithelial cell line (HCjE) grown with all-trans-retinoic acid (RA). The analysis showed that the membrane-associated mucin MUC16 was induced by RA and that secretory phospholipase A2 Group IIA (sPLA2-IIA), the gene most upregulated by RA, was induced earlier. Since eicosanoids, metabolites of arachidonic acid, which is produced by sPLA2 catalysis of membrane phospholipids, have been demonstrated to affect mucin production, we sought to determine if the sPLA2 induction in HCjE cells was associated with RA induction of MUC16. Methods. HCjE cells were cultured with or without RA for 3, 6, 24 and 48 hours. Complementary RNA prepared from RNA of the HCjE cells was hybridized to human gene chips (HG-U133A; Affymetrix) and analyzed using Rosetta Resolver software. Microarray data on mucin expression were validated by real-time PCR. To investigate whether sPLA2 is associated with RA-induced MUC16 upregulation, HCjE cells were incubated with RA and the broad spectrum PLA2 inhibitor, aristolochic acid (ArA) or the specific sPLA2-IIA inhibitor LY315920, followed by analysis of MUC16 mRNA and protein by real-time PCR and Western blot analysis. Results. After RA addition, 28 transcripts were upregulated and 6 downregulated by over 2.0-fold (p < 0.01) at both 3 and 6 hours (early phase). Eighty gene transcripts were upregulated and 45 downregulated at both 24 and 48 hours (late phase). Group IIA sPLA2, significantly upregulated by 24 hours, and MUC16 were the most upregulated RNAs by RA at 48 hours. sPLA2 upregulation by RA was confirmed by Western blot analysis. When HCjE cells were incubated with RA plus ArA or specific inhibitor of sPLA2-IIA, LY315920, the RA-induced MUC16 mRNA was significantly reduced (p < 0.01). Conclusion. The retinoic acid-associated upregulation of membrane-associated mucin MUC16 at late phase appears to be through sPLA2-IIA. Upregulation of this hydrophilic membrane-associated mucin may be one of the important mechanisms by which vitamin A facilitates maintenance of the wet-surfaced phenotype on the ocular surface. Experiment Overall Design: Time course of retinoic acid treatment of human conjunctival epithelial cells: 0 (control), 3, 6, 12, 24, and 48 hours. 2 samples per time point.
Project description:Dry eye syndrome (DES) is a complex ocular condition characterized by an unstable tear film and inadequate tear production, leading to tissue damage. Despite its common occurrence, there is currently no comprehensive in vitro model that accurately reproduce the cellular characteristics of DES. Here we modified a corneal epithelium-on-a-chip (CEpOC) model to recapitulate DES by subjecting HCE-T human corneal epithelial cells to an air-liquid (AL) interface stimulus. We then assessed the effects of AL stimulation both in the presence and absence of diclofenac (DCF). Transcriptomic analysis revealed distinct gene expression changes in response to AL and AL_DCF, affecting pathways related to development, epithelial structure, inflammation, and extracellular matrix remodeling. Both treatments upregulated PIEZO2, linked to corneal damage signaling, while downregulating OCLN, involved in cell-cell junctions. They increased the expression of inflammatory genes (e.g., IL6) and reduced mucin production genes (e.g., MUC16), reflecting dry eye characteristics. TGFB1, crucial for corneal wound healing, was slightly downregulated in AL_DCF, potentially affecting wound healing processes rather than reducing inflammation by DCF. Metabolomic analysis showed increased secretion of metabolites associated with cell damage and inflammation (e.g., methyl-2-oxovaleric acid, 3-methyl-2-oxobutanoic acid, lauroyl-carnitine) in response to AL and even more with AL_DCF, indicating a shift in cellular metabolism. This study showcases the utilization of AL stimulus within the CEpOC as a comprehensive approach to faithfully reproduce the cellular characteristics of DES.
Project description:Purpose. How vitamin A contributes to the maintenance of the wet-surfaced phenotype at the ocular surface is not well understood. We sought to identify vitamin A responsive genes in ocular surface epithelia using gene microarray analysis of cultures of a human conjunctival epithelial cell line (HCjE) grown with all-trans-retinoic acid (RA). The analysis showed that the membrane-associated mucin MUC16 was induced by RA and that secretory phospholipase A2 Group IIA (sPLA2-IIA), the gene most upregulated by RA, was induced earlier. Since eicosanoids, metabolites of arachidonic acid, which is produced by sPLA2 catalysis of membrane phospholipids, have been demonstrated to affect mucin production, we sought to determine if the sPLA2 induction in HCjE cells was associated with RA induction of MUC16. Methods. HCjE cells were cultured with or without RA for 3, 6, 24 and 48 hours. Complementary RNA prepared from RNA of the HCjE cells was hybridized to human gene chips (HG-U133A; Affymetrix) and analyzed using Rosetta Resolver software. Microarray data on mucin expression were validated by real-time PCR. To investigate whether sPLA2 is associated with RA-induced MUC16 upregulation, HCjE cells were incubated with RA and the broad spectrum PLA2 inhibitor, aristolochic acid (ArA) or the specific sPLA2-IIA inhibitor LY315920, followed by analysis of MUC16 mRNA and protein by real-time PCR and Western blot analysis. Results. After RA addition, 28 transcripts were upregulated and 6 downregulated by over 2.0-fold (p < 0.01) at both 3 and 6 hours (early phase). Eighty gene transcripts were upregulated and 45 downregulated at both 24 and 48 hours (late phase). Group IIA sPLA2, significantly upregulated by 24 hours, and MUC16 were the most upregulated RNAs by RA at 48 hours. sPLA2 upregulation by RA was confirmed by Western blot analysis. When HCjE cells were incubated with RA plus ArA or specific inhibitor of sPLA2-IIA, LY315920, the RA-induced MUC16 mRNA was significantly reduced (p < 0.01). Conclusion. The retinoic acid-associated upregulation of membrane-associated mucin MUC16 at late phase appears to be through sPLA2-IIA. Upregulation of this hydrophilic membrane-associated mucin may be one of the important mechanisms by which vitamin A facilitates maintenance of the wet-surfaced phenotype on the ocular surface. Keywords: time course
Project description:Purpose: To investigate the mechanism for developing dry eye disease in the Pinkie mouse strain with a loss of function RXR mutation. Methods: Measures of dry eye disease were assessed in the cornea and conjunctiva. Expression profiling by single-cell RNA sequencing (scRNA-seq)was performed to compare gene expression in conjunctival immune cells. Conjunctival immune cells were immunophenotyped by flow cytometry and confocal microscopy. Activity of RXR ligand 9-cis retinoic acid (RA) was evaluated in cultured monocytes and T cells. Results: Compared to wild type (WT) C57BL/6, Pinkie has increased signs of dry eye disease, including corneal barrier disruption, conjunctival cornification and goblet cell loss, and corneal vascularization, opacification, and ulceration with aging. scRNA-seq of conjunctival immune cells identified T cells as the predominant IL-17 expressing population in both strains and there is a 4-fold increased percentage of T cells in Pinkie. Compared to WT, significantly increased expression of IL-17a and IL-17f in conventional T cells and IL-17f in T cells was found in Pinkie. Flow cytometry and immunostaining revealed an increased number of IL-17+ T cells in Pinkie. Tear concentration of the IL-17 inducer IL-23 is significantly higher in Pinkie. 9-cis RA treatment suppresses stimulated IL-17 production by T and stimulatory activity of monocyte supernatant on T cell IL-17 production. Compared to WT bone marrow chimeras, Pinkie chimeras have increased IL-17+ T cells in the conjunctiva after desiccating stress and anti-IL-17 treatment suppresses dry eye induced corneal MMP-9 production/activity and conjunctival goblet cell loss. Conclusion: These findings indicate that RXR suppresses generation of dry eye disease inducing T17 cells in the conjunctiva and identifies RXR as a potential therapeutic target in dry eye.
Project description:In 2005, we determined the glyco-gene expression profile of three normal subjects ( www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE27593). This led to information on the biosynthesis of mucin O-glycans and glycoproteins that may be involved in the protection of the ocular surface. The interaction of the most highly expressed glycoprotein identified by the glyco-gene chip, galectin-3, with other ligands at the ocular surface (i.e., mucin O-glycans), is now under intense study in our laboratory, and has lead to a collaboration with another group in the glycobiology field. Patients with dry eye disease have an alteration of mucin O-glycans at the ocular surface, but the molecular mechanism(s) leading to this alteration remain unknown. In this experiment we (i) pooled three pathological samples per chip to reduce variability, and (ii) used three additional chips to include pooled control samples (normal subjects). Currently, we have RNA from 9 patients with dry eye disease, which have been divided it in 3 groups (D1, D2, and D3)—each group containing RNA pooled from 3 patients. We request three additional chips to include control samples (normal subjects). At this moment, we have RNA from 9 normal subjects, which have been divided it in 3 groups (N1, N2, and N3)—each group containing RNA pooled from 3 normal subjects. RNA was extracted in Trizol, purified using RNeasy column, and dissolved in water were sent to Microarray Core (E). The RNA was amplified, labeled, and hybridized to the GLYCOv3 microarrays. Data Analysis was done by Microarray Core (E).
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:In this study, we transferred gut microbiota of SS-like autoimmune dry eye disease model mice to conventional B6 mice (NOD-FMT). After the transfer, NOD-FMT mice experienced a dramatic change in the gut microbiomes and showed clinicopathological features of SS, including increased corneal fluorescein staining score, decreased tear production, elevated levels of IL-6 mRNA, decreased levels of MUC5AC mRNA encoding mucin. Additionally, we observed that NOD-FMT mice shared stereotypic B cell receptor (BCR) clonotypes with a much higher frequency compared to control group. B cell clones encoding these stereotypic BCR clonotypes developed and expanded locally in the lacrimal gland, and achieved systemic presence in certain clonotypes.