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Amrita Saha, Ashrafali Mohamed Ismail, Xiaohong Zhou, James Chodosh, Jaya Rajaiya; High mobility group box 1 mediated crosstalk between infected corneal epithelial cells and stromal keratocytes. Invest. Ophthalmol. Vis. Sci. 2021;62(8):863.
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© ARVO (1962-2015); The Authors (2016-present)
Ocular surface infection by viruses within human adenovirus species D (HAdV-D) causes epidemic keratoconjunctivitis (EKC). Subepithelial infiltrate (SEI) formation in the cornea is the most significant long-term complication of EKC, and presents in about one-third of cases. However, the mechanism of SEI formation after adenoviral infection of the cornea remains uncertain. High-mobility group box protein 1 (HMGB1) is an endogenous danger signal molecule and chemokine that variably regulates inflammatory responses. Although HMGB1 has been implicated previously in viral infections, and may play a role in bacterial keratitis, its role in EKC has not been studied.
hTERT-immortalized human corneal epithelial (THE) cells and primary human corneal fibroblasts (HCFs) were infected with HAdV-D37 or HAdV-C5 at MOI = 5, and cell supernatants were collected through 48 hours post infection. Mass spectrometry (LC-MS/MS) analysis was performed on infected human corneal cells. Immunoblotting was performed on infected cell supernatants, and on cytoplasmic and nuclear cellular fractions, using acetylated HMGB1 antibody. ELISA for secreted HMGB1 was conducted on cell-free supernatants, and HMGB1 gene expression was studied using real-time qPCR. Confocal microscopy was performed to visualize HMGB1 translocation. Cytokine expression by HCFs treated with rHMGB1 was analyzed using human cytokine protein arrays.
HAdV-D37 infection resulted in HMGB1 translocation from the nucleus to the cytoplasm and then to the extracellular space in THE cells, but not in HCFs. HAdV-C5, a virus not associated with EKC, did not induce secretion of HMGB1 from either cell type. Finally, recombinant active HMGB1 treatment of HCFs triggered expression of pro-inflammatory mediators.
This study provides insights into possible mechanism of corneal SEI formation in EKC. Our results suggest that HMGB1 expressed by adenovirus infected corneal epithelial cells could induce underlying stromal cells to express pro-inflammatory mediators, leading indirectly to the development of SEI. HMGB1 may be a viable therapeutic target for preventing the corneal stromal complications of EKC.
This is a 2021 ARVO Annual Meeting abstract.
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