Project description:Dry eye is a common ocular inflammatory disorder characterized by tear film instability and reduced tear production. There is increasing evidence that homeostasis of the ocular surface is impacted by the intestinal microbiome. We are interested in investigating the potential role of microbially produced small molecules in mediating the interaction between the intestinal microbiota and the ocular surface. One such molecule is butyrate, a short-chain fatty acid (SCFA) produced by certain members of the gut microbiota through fermentation of dietary fiber. We have shown that oral administration of tributyrin, a prodrug form of butyrate, is protective of the ocular surface in mice undergoing desiccating stress. To gain insight into the mechanism, we analyzed gene expression in conjunctival tissue from mice treated with either tributyrgn or vehicle control.
Project description:Tears are a biological fluid that has diagnostic potential for ocular diseases. Extracellular vesicles (EVs), wildly detected in various biofluids including tears, are nanoparticles released by living cells and considered as promising detection sources for non-invasive liquid biopsy. Understanding the roles of tears and tear-EVs in ocular diseases such as dry eye can facilitate the studies of clinical diagnosis, which usually entails detecting such liquid objects with a rapid and effective method. In this study, we utilized a mass spectrometry based strategy to analyze peptidome/proteome profiles of tear and EVs for rapid dry eye diagnosis. Nano-sized EVs were isolated from tears of either healthy control (HC) individuals or dry eye syndrome (DES) patients, and the tear compositions were further analyzed by tracking their fingerprints with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS). The fingerprints of tear-EVs could be observed in a dose-dependent manner as well as tears, allowing comparing their discriminant peaks between tears and EVs. By analyzing these peaks, the fingerprints of both tear and tear-EVs were showed to have a capability of distinguishing DES patients from HC donors, and providing an efficient way for screening potential DES biomarkers. The proposed tear and EV fingerprinting approach is expected to be a potential tool in rapid diagnosis of ocular disease and in-depth researches of pathogenesis.
Project description:Corneal architecture is essential for vision and is greatly perturbed by the absence of tears due to the highly prevalent disorder dry eye. With no regenerative therapies available, pathological alterations of the ocular surface in response to dryness, including persistent epithelial defects and poor wound healing, result in lifelong morbidity. Here, using a mouse model of aqueous-deficient dry eye, we reveal that topical application of the synthetic tear protein lacripep reverses the pathological outcomes of dry eye through restoring the extensive network of corneal nerves that are essential for tear secretion, barrier function, epithelial homeostasis and wound healing. Intriguingly, the restorative effects of lacripep occur despite extensive immune cell infiltration, suggesting tissue reinnervation and regeneration can be achieved under chronic inflammatory conditions. In summary, our data highlight lacripep as a first-in-class regenerative therapy for returning the cornea to a near homeostatic state in individuals who suffer from dry eye.
Project description:Glycosylation of proteins is one of the most common post-translational modification (PTM) and plays important regulatory functions in diverse biological processes such as protein stability or cell signaling. Accordingly, glycoproteins are also a consistent part of the human tear film proteome maintaining the proper function of the ocular surface and forming the first defense barrier of the ocular immune system. Irregularities in the glycoproteomic composition of the tear film might promote development of chronic eye diseases indicating glycoproteins as valuable source for biomarker discovery or drug target identification. The present study aimed to develop a lectin-based affinity method for the enrichment and concentration of tear glycoproteins/glycopeptides and the characterization of their specific N-glycosylation sites by high-resolution mass spectrometry (MS). For method development and evaluation, we accumulated first native glycoproteins from human tear sample pools and assessed the enrichment efficiency of different lectin column systems by 1D gel electrophoresis and specific protein stainings (Coomassie and glycoproteins). The best-performing multi-lectin column system (comprising the four lectins ConA, JAC, WGA and UEA I, termed as 4L) was applied for glycopeptide enrichment from human tear sample digests followed by MS-based detection and localization of their specific N-glycosylation sites. As main result, the present study identified in total 26 N glycosylation sites of 11 N-glycoproteins in tear sample pools of healthy individuals (n=3 biological sample pools). Amongst others, we identified tear film proteins lactotransferrin (N497 and N642, LTF), Ig heavy chain constant α-1 (N144 and 340, IGHA1), prolactin-inducible protein (N105, PIP) as well as extracellular lacritin (N105, LACRT) as highly reliable and significant N glycoproteins, which were already associated with the pathogenesis of various chronic eye diseases such as the dry eye syndrome (DES). In conclusion, the results of the present study will serve as important tear film N-glycoprotein catalogue for future studies focusing the human tear film and ocular surface-related inflammatory diseases.
Project description:Aspergillus flavus and Fusarium sp. are primary causative agents of keratitis that results in corneal tissue damage leading to vision loss. The tear proteome of control and keratitis patients was profiled and compared. A total of 1873 proteins from control and 1400 proteins from patient tear were identified by mass spectrometry. While 847 proteins were found to be glycosylated in the patient tear, only 726 were glycosylated in control tear. Some tear proteins showed alterations in their glycosylation pattern after infection. Complement system proteins, proteins specific for neutrophil extracellular traps and proteins involved in would healing were found only in the patient tear. The presence of these innate immune system proteins in patient's tear supports previous data indicating the involvement of neutrophil and complement pathways in antifungal defense. High levels of wound healing proteins in keratitis patient tear implied activation of tissue repair. The early appearance of host defense proteins and wound healing response indicates that tear proteins could be used as an early marker system for monitoring the progression of pathogenesis. Identification of negative regulators of the defense pathways in keratitis tear indicates an intricate balance of pro and anti-defense mechanisms operating in fungal infection of the eye.
Project description:In humans, the lacrimal gland produces the aqueous component of the tear film, which e.g. moistens and nourishes the ocular surface to maintain ophthalmic health. Decreased production of the aqueous component leads to the development of dry eye disease, which affects over 250 million people worldwide. Despite the impact on patients, the availability of primary human material to study underlying disease mechanisms is severely constrained. Here, we report the development of an immortalized human lacrimal gland epithelial cell line that improves accessibility to study the molecular pathogenesis-mechanisms of dry eye disease and link them to causal treatments.
2024-04-17 | GSE239464 | GEO
Project description:Effects of Intense Pulsed Light on Tear Film TGF-beta and Microbiome in Ocular Rosacea with Dry Eye
Project description:Exposure to tear fluid can enhance corneal epithelial cells' ability to resist bacterial virulence mechanisms by upregulating epithelial-derived innate defense genes. The aim of this study was to further elucidate the mechanisms by which tear fluid modulates epithelial cell susceptibility to P. aeruginosa internalization and the relationship to known to be upregulated genes with tear fluid exposure. The hypothesis tested was that tear fluid effects on epithelial cells involve the induction of microRNA expression to modify innate defense gene responses to bacterial challenge. Human corneal epithelial cells were incubated in either 40 ul of fresh human tear fluid or high calcium KGM without antibiotics for 16 hours before extraction or before incubation with P. aeruginosa antigens for 3 h then extraction.
Project description:We performed RNA-seq on six samples of P20 Sprague Dawley rat superior colliculus, three control rats that underwent eye opening at P14 until P20 and three deprived rats which had their eyes glued closed from P14 until P20. Each sample was created from two pooled colliculi.