ABSTRACT
Purpose: Ocular surface discomfort and dry eye disease are caused by a dysfunctional tear film. The efficacy of lubricating eye drops on the human eye is known, but the compositions may show differential effects on rescuing the tear film. Mucins form a critical layer of the tear film, a reduction of which may be causative for ocular surface conditions. Therefore, it is essential to develop relevant human?derived models to test mucin production. Methods: Human corneoscleral rims were obtained from a healthy donor (n = 8) post?corneal keratoplasty and cultured in DMEM/F12 media. Hyperosmolar stress mimicking dry eye disease was induced by exposing the corneoscleral rim tissues to +200 mOsml NaCl?containing media. The corneoscleral rims were treated with polyethylene glycol–propylene glycol (PEG–PG)?based topical formulation. Gene expression analysis was performed for NFAT5, MUC5AC, and MUC16. Secreted mucins were measured by enzyme?linked immunosorbent assay (ELISA) (Elabscience, Houston, TX, USA) for MUC5AC and MUC16. Results: The corneoscleral rims responded to hyperosmolar stress by upregulating NFAT5, a marker for increased osmolarity, as observed in the case of dry eye disease. The expression of MUC5AC and MUC16 was reduced upon an increase in hyperosmotic stress. The corneoscleral rim tissues showed induction of MUC5AC and MUC16 expression upon treatment with PEG–PG topical formulation but did not show significant changes in the presence of hyperosmolar treatments. Conclusion: Our findings showed that PEG–PG?based topical formulation slightly alleviated hyperosmolar stress?induced decrease in MUC5AC and MUC16 gene expression that is encountered in DED
ABSTRACT
Purpose: Dry eye disease (DED) is characterized by altered ocular surface proinflammatory and antiinflammatory factors. Interferons (IFNs) are a class of pleiotropic cytokines well known for their antimicrobial, inflammatory, and immunomodulatory roles. Hence, this study investigates the ocular surface expression of different types of IFNs in patients with DED. Methods: The cross?sectional, observational study included patients with DED and normal subjects. Conjunctival impression cytology (CIC) samples were obtained from the study subjects (controls, n = 7; DED, n = 8). The mRNA expression levels of type 1 IFN (IFN?, IFN?), type 2 IFN (IFN?), and type 3 IFN (IFN?1, IFN?2, IFN?3) were measured by quantitative PCR (polymerase chain reaction) in CIC samples. IFN? and IFN? expression under hyperosmotic stress was also studied in human corneal epithelial cells (HCECs) in vitro. Results: The mRNA expression levels of IFN? and IFN? were significantly lower and that of IFN? was significantly higher in DED patients compared to healthy controls. The mRNA levels of IFN?, IFN?, and IFN? were significantly lower compared to IFN? in DED patients. An inverse association between tonicity?responsive enhancer?binding protein (TonEBP; hyperosmotic stress maker) and IFN? or IFN? expression and a positive association between TonEBP and IFN? expression was observed in CIC samples. The expression of IFN? was lower than IFN? in HCECs undergoing hyperosmotic stress compared to HCECs without the stress. Conclusion: The presence of an imbalance between type 1 and type 2 IFNs in DED patients suggests newer pathogenic processes in DED, plausible ocular surface infection susceptibility in DED patients, and potential therapeutic targets in the management of DED
ABSTRACT
With various diseases ravaging internationally, the demands for recombinant adenoviral vector (Adv) vaccines have increased dramatically. To meet the demand for Adv vaccine, development of a new cell culture process is an effective strategy. Applying hyperosmotic stress in cells before virus infection could increase the yield of Adv in batch culture mode. Emerging perfusion culture can significantly increase the yield of Adv as well. Therefore, combining the hyperosmotic stress process with perfusion culture is expected to improve the yield of Adv at high cell density. In this study, a shake flask combined with a semi-perfusion culture was used as a scaled-down model for bioreactor perfusion culture. Media with osmotic pressure ranging from 300 to 405 mOsm were used to study the effect of hyperosmotic stress on cell growth and Adv production. The results showed that using a perfusion culture process with a hyperosmotic pressure medium (370 mOsm) during the cell growth phase and an isosmotic pressure medium (300 mOsm) during the virus production phase effectively increased the yield of Adv. This might be due to the increased expression of HSP70 protein during the late phases of virus replication. The Adv titer in a bioreactor with such a process reached 3.2×1010 IFU/mL, three times higher than that of the traditional perfusion culture process. More importantly, this is the first time that a strategy of combining the hyperosmotic stress process with perfusion culture is applied to the production of Adv in HEK 293 cells. It also reveals the reason why the hyperosmotic stress process increased the yield of Adv, which may facilitate the process optimization of for producing other Adv in HEK 293 cells.
Subject(s)
Humans , HEK293 Cells , Genetic Vectors/genetics , Batch Cell Culture Techniques , Bioreactors , PerfusionABSTRACT
Cells consistently face stressful conditions, which cause them to modulate a variety of intracellular processes and adapt to these environmental changes via regulation of gene expression. Hyperosmotic and oxidative stresses are significant stressors that induce cellular damage, and finally cell death. In this study, oligonucleotide microarrays were employed to investigate mRNA level changes in cells exposed to hyperosmotic or oxidative conditions. In addition, since heat shock protein 70 (HSP70) is one of the most inducible stress proteins and plays pivotal role to protect cells against stressful condition, we performed microarray analysis in HSP70 overexpressing cells to identify the genes expressed in a HSP70 dependent manner. Under hyperosmotic or oxidative stress conditions, a variety of genes showed altered expression. Down regulation of protein phosphatase1 beta (PP1 beta) and sphingosine 1 phosphate phosphatase 1 (SPPase1) was detected in both stress conditions. Microarray analysis of HSP70 overexpressing cells demonstrated that diverse mRNA species depend on the level of cellular HSP70. Genes encoding lysyl oxidase, thrombospondin 1, and procollagen displayed altered expression in all tested conditions. The results of this study will be useful to construct networks of stress response genes.