Abstract
Purpose :
Parainflammation or overt inflammation are associated with the onset and propagation of several ocular disorders. The purpose of this study was to test a peptide derived from suppressor of cytokine signaling 1 (SOCS1) for protection against inflammation and changes in tight junction properties in ARPE-19 cells.
Methods :
The kinase inhibitory region (KIR) of SOCS1 spanning from residues 53 to 68 was conjugated to polyarginine (R9) for cell penetration was tested for its anti-inflammatory properties in ARPE-19 cells treated with TNFα or IL-17A, the major culprits in several ocular pathologies. Induction of inflammatory cytokines and chemokine was evaluated by RT-qPCR. Concomitant secretion of inflammatory cytokine in the supernatant was measured by ELISA. Since these inflammatory cytokines act through the transcription factor, NF-kB, a luciferase reporter linked to NF-kB promoter was used to assess the effect on its activity. Integrity of the cell monolayer was assessed by immunostaining with zona occludin 1 (ZO-1) antibody and by transepithelial electrical resistance (TEER) measurement in cells treated with TNFα or IL-17A in the presence or absence of SOCS1 peptide.
Results :
RT-qPCR assays revealed significant induction of IL-1β, IL-6 and CCL-2 in TNFα treated cells, which was attenuated by SOCS1 peptide. Increased secretion of IL-1β in supernatants by TNFα treatment was suppressed when SOCS1 peptide was simultaneously present. Induction of NF-kB activity by TNFα was suppressed in the presence of SOCS1 peptide. Treatment with TNFα or IL-17A led to a decrease in TEER that was prevented in the presence of SOCS1 peptide. Protection of the integrity of the tight junctions was also documented by ZO-1 staining in cells treated with TNFα or IL-17 in the presence of SOCS1.
Conclusions :
Since the retinal pigment epithelium cells serve the crucial role of maintaining blood-retinal barrier, our demonstration that SOCS1 peptide exhibits anti-inflammatory properties and protects against the damage to barrier properties suggests that it will have therapeutic potential in treatment of ocular diseases such as autoimmune uveitis and age-related macular degeneration.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.