Induction of interleukin-8 in human retinal pigment epithelial cells after denuding injury

Role of T cell-induced autoimmune response in the pathogenesis of glaucoma

PURPOSE

This review aims to elucidate the role of T cell-induced autoimmune responses in the pathogenesis of glaucoma, focusing on the immunological changes contributing to retinal ganglion cell (RGC) damage.

METHODS

A comprehensive review of recent studies examining immunological mechanisms in glaucoma was conducted. This included analyses of T cell interactions, heat shock proteins (HSPs), and resultant autoimmune responses. Key findings from experimental models and clinical observations were synthesized to present a coherent understanding of immune dynamics in glaucoma.

RESULTS

Glaucoma is a neurodegenerative disease marked by optic nerve atrophy and irreversible vision loss due to RGC damage. The disease is etiologically heterogeneous, with multiple risk factors and pathogenic mechanisms. Recent research highlights the dual immunomodulatory role of T cells in immune protection and injury. T cells, pre-sensitized by bacterial HSPs, can cross-react with endogenous HSPs in RGCs under stress, leading to autoimmune damage. Elevated levels of HSP autoantibodies and abnormal T cell activity have been observed in glaucoma patients, indicating a significant autoimmune component in disease progression.

CONCLUSIONS

T cell-induced autoimmune responses are crucial in the pathogenesis of glaucoma, contributing to RGC degeneration beyond the effects of elevated intraocular pressure. Understanding these immunological mechanisms is vital for developing targeted neuroprotective therapies for glaucoma.

Vitreous Olink proteomics reveals inflammatory biomarkers for diagnosis and prognosis of traumatic proliferative vitreoretinopathy

Background

The aim of this study was to identify inflammatory biomarkers in traumatic proliferative vitreoretinopathy (TPVR) patients and further validate the expression curve of particular biomarkers in the rabbit TPVR model.

Methods

The Olink Inflammation Panel was used to compare the differentially expressed proteins (DEPs) in the vitreous of TPVR patients 7-14 days after open globe injury (OGI) (N = 19) and macular hole patients (N = 22), followed by correlation analysis between DEPs and clinical signs, protein-protein interaction (PPI) analysis, area under the receiver operating characteristic curve (AUC) analysis, and function enrichment analysis. A TPVR rabbit model was established and expression levels of candidate interleukin family members (IL-6, IL-7, and IL-33) were measured by enzyme-linked immunosorbent assay (ELISA) at 0, 1, 3, 7, 10, 14, and 28 days after OGI.

Results

Forty-eight DEPs were detected between the two groups. Correlation analysis showed that CXCL5, EN-RAGE, IL-7, ADA, CD5, CCL25, CASP8, TWEAK, and IL-33 were significantly correlated with clinical signs including ocular wound characteristics, PVR scoring, PVR recurrence, and final visual acuity (R = 0.467-0.699, p < 0.05), and all with optimal AUC values (0.7344-1). Correlations between DEP analysis and PPI analysis further verified that IL-6, IL-7, IL-8, IL-33, HGF, and CXCL5 were highly interactive (combined score: 0.669-0.983). These DEPs were enriched in novel pathways such as cancer signaling pathway (N = 14, p < 0.000). Vitreous levels of IL-6, IL-7, and IL-33 in the rabbit TPVR model displayed consistency with the trend in Olink data, all exhibiting marked differential expression 1 day following the OGI.

Conclusion

IL-7, IL-33, EN-RAGE, TWEAK, CXCL5, and CD5 may be potential biomarkers for TPVR pathogenesis and prognosis, and early post-injury may be an ideal time for TPVR intervention targeting interleukin family biomarkers.

Minimally interface vitrectomy for rhegmatogenous retinal detachment with a single break in young patients

Purpose

This study evaluates a new surgical technique consisting of minimal vitreous removal under air (minimal interface vitrectomy; MIV) to reduce postoperative complications while preserving the ability to address surgical factors at the retinal break.

Methods

This retrospective analysis examined the outcomes of minimal interface vitrectomies in consecutive cases, with a minimum 12-month follow-up period, of primary rhegmatogenous retinal detachment (RRD), recurrent RRD after pars plana vitrectomy (PPV), or failed surgery after primary scleral buckling surgery (SBS).

Results

Twelve eyes of 12 patients with RRD underwent MIV. The total surgical duration was 190–300 s (mean, 245.25 s). Eight (66.7%) eyes were treated with cryotherapy, and 4 (33.3%) with endolaser to seal the retinal break. Successful, complete retinal reattachment was achieved in all eyes and maintained during follow-up. No intra- or postoperative complications occurred and no patients developed inflammation or cataract during follow-up.

Conclusion and Importance

We effectively removed traction and subretinal fluid and treated breaks with endolaser or cryotherapy by using a novel minimal interface vitrectomy technique in this selected population.

Acute mechanical stress in primary porcine RPE cells induces angiogenic factor expression and in vitro angiogenesis

Background

Choroidal neovascularization (CNV) is a major cause of blindness in patients with age-related macular degeneration. CNV is characterized by new blood vessel growth and subretinal fluid accumulation, which results in mechanical pressure on retinal pigment epithelial (RPE) cells. The overexpression of RPE-derived angiogenic factors plays an important role in inducing CNV. In this work, we investigated the effect of mechanical stress on the expression of angiogenic factors in porcine RPE cells and determined the impact of conditioned medium on in-vitro angiogenesis.

Results

The goal of this study was to determine whether low levels of acute mechanical stress during early CNV can induce the expression of angiogenic factors in RPE cells and accelerate angiogenesis. Using a novel device, acute mechanical stress was applied to primary porcine RPE cells and the resulting changes in the expression of major angiogenic factors, VEGF, ANG2, HIF-1α, IL6, IL8 and TNF-α, were examined using immunocytochemistry, qRT-PCR, and ELISA. An in vitro tube formation assay was used to determine the effect of secreted angiogenic proteins due to mechanical stress on endothelial tube formation by human umbilical vein endothelial cells (HUVECs). Our results showed an increase in the expression of VEGF, ANG2, IL-6 and IL-8 in response to mechanical stress, resulting in increased in vitro angiogenesis. Abnormal epithelial-mesenchymal transition (EMT) in RPE cells is also associated with CNV and further retinal degeneration. Our qRT-PCR results verified an increase in the expression of EMT genes, CDH2, VIM and FN1, in RPE cells.

Conclusions

In conclusion, we showed that acute mechanical stress induces the expression of major angiogenic and EMT factors and promotes in vitro angiogenesis, suggesting that mechanical stress plays a role in promoting aberrant angiogenesis in AMD.

Peripheral blood mononuclear cells from neovascular age-related macular degeneration patients produce higher levels of chemokines CCL2 (MCP-1) and CXCL8 (IL-8)

Background

Infiltrating immune cells including monocytes/macrophages have been implicated in the pathogenesis of neovascular age-related macular degeneration (nAMD). The aim of this study was to investigate the cytokine and chemokine expression and secretion profile of peripheral blood mononuclear cells (PBMCs) from nAMD patients and the relationship between the cytokine/chemokine expression profile and clinical phenotype of nAMD, including macular fibrosis, macular atrophy or the responsiveness to anti-VEGF therapy.

Methods

One hundred sixty-one nAMD patients and 43 controls were enrolled in this study. nAMD patients were divided into subgroups based on the presence/absence of (1) macular atrophy, (2) macular fibrosis and (3) responsiveness to anti-VEGF therapy; 25–30 ml of peripheral blood were obtained from all participants and 5 ml were used for serum collection, and the remaining were used for PBMC isolation using density gradient centrifugation. Intracellular cytokine expressions by PBMCs following phorbol 12-myristate 13-acetate (PMA) and ionomycin stimulation were examined using flow cytometry. Cytokine productions in lipopolysaccharides (LPS)-or 1% oxygen -treated PBMC were measured using cytometric bead array (CBA) assay. In addition, cytokine and chemokine levels in the serum were also measured by CBA assay.

Results

PBMCs from nAMD patients secreted higher levels of IL-8, CCL2 and VEGF, especially following LPS and 1% oxygen stimulation, than those from controls. 60~80% of IL-8 producing cells were CD11b⁺CD3⁻ monocytes. The percentage of CD11b⁺CD3⁻ IL-8⁺ was significantly increased in nAMD patients compared to controls. PBMCs from nAMD patients without macular fibrosis produced the highest levels of IL-8 and CCL2, whilst PBMCs from nAMD patients with macular atrophy produced highest levels of VEGF. In addition, PBMCs from patients who partially responded to anti-VEGF produced higher levels of IL-8 compared to the cells from complete responders. Interestingly, serum level of CCL2 was not increased in nAMD patients although there was a trend of increased IL-8 in nAMD patients.

Conclusions

PBMCs, in particular monocytes, may contribute to CNV development in nAMD through secreting elevated levels of IL-8, CCL2 and VEGF after they are recruited to the macula. Apart from VEGF, IL-8 and CCL2 may be additional targets for nAMD management.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-017-0820-y) contains supplementary material, which is available to authorized users.

Nicotine alters morphology and function of retinal pigment epithelial cells in mice

To study the effects of nicotine on retinal pigment epithelium (RPE) cells in vivo and in vitro, (Balb/c x C57Bl/6) F1 mice were given water containing 100 microg/mL nicotine for six months. Cultured fetal RPE cells were treated with nicotine or lipopolysaccharide for seventy-two hours. Expression of matrix metalloproteinase protein (MMP)2, MMP9, and VEGF was measured using Western blot. Expression of IL6 and IL8 was measured using real-time polymerase chain reaction or enzyme-linked immunosorbent assay. Electron microscopy was performed to observe the effects of nicotine on morphological changes of mice retina or cultured RPE cells, and filamentous actin in RPE cells was stained with phalloidin. Electron microscopy revealed that nicotine-treated mice showed thinner outer nuclear layers, fewer pigment granules in RPE cells, and a damaged photoreceptor-RPE interface when compared with age-control mice. When added to cultured RPE cells, nicotine induced accumulation of osmiophilic lamellated intracellular inclusions in cytoplasm, mitochondrion hypertrophy and vacuolar degeneration, and redistribution of actin in cells without affecting cell proliferation. Expression of MMP2 and MMP9 in nicotine-treated RPE cells was decreased. Nicotine-induced changes in RPE morphology and function provide insight into pathogenesis of smoking-related retinal diseases.

Modulation of migration and Ca2+ signaling in retinal pigment epithelium cells by recombinant human CTGF

PURPOSE

The migration of retinal pigment epithelium (RPE) cells is an initial step in the development of proliferative vitreoretinopathy (PVR). We investigated the expression of connective tissue growth factor (CTGF) in an in vitro model of wound healing and effects of recombinant human CTGF (rhCTGF) on modulating migration and Ca(2+) signaling in RPE cells.

METHODS

Cultured human RPE monolayers were used to establish a wound-healing model. Western blot and in situ hybridization were used to detect the CTGF expression in RPE cells. Migration of RPE cells was measured under the stimulation of rhCTGF alone or in combination with dexamethasone (DEX) or 8-Br-cAMP. To determine the concentration of cytoplasmic-free Ca(2+) ([Ca(2+)]i) responding to CTGF, the fluo-3/AM-loaded RPE cells were observed with a laser scanning confocal microscope.

RESULTS

The CTGF expression first increased after being wounded in RPE cells, then reached a peak and maintained at a high level. The positive expression was mainly at the edge of scrape and in motile RPE cells. rhCTGF-stimulated RPE cells migrated in a dose-dependent manner, and both DEX and 8-Br-cAMP could significantly inhibit the CTGF-induced migrations. CTGF induced a (Ca(2+))i elevation in RPE cells in a concentration-dependent manner. Moreover, stimulation of RPE cells with CTGF and DEX or 8-Br-cAMP counteracted the elevation of (Ca(2+))i induced by CTGF.

CONCLUSIONS

The CTGF expression could be induced by an in vitro model of scrape wounding. rhCTGF stimulated the migration and Ca(2+) signal pathway in RPE cells in a dose-dependent manner, and DEX and 8-Br-cAMP suppressed this effect. Our results indicate that CTGF is involved in the wound-healing process and plays an important role in the pathogenesis of intraocular proliferative diseases.

Efficacy of early systemic betamethasone or cyclosporin A after corneal alkali injury via inflammatory cytokine reduction

PURPOSE

To evaluate the effects of early systemic administration of betamethasone or cyclosporin A (CsA) on inflammatory cytokine expression and corneal damage after alkali injury.

METHODS

Sixty-five Wistar rat corneas injured with 1N NaOH were divided into three groups: untreated, betamethasone-treated and CsA-treated. Both agents were administered systemically and daily during the first 7 days after injury. Interleukin (IL)-1alpha, -6 and -8 concentrations in the injured corneas were measured with ELISA at 2, 4 and 7 days after injury. Corneal damage was evaluated by scoring clinical findings.

RESULTS

In untreated injured corneas, IL-1alpha, -6 and -8 were markedly elevated during the 7-day period following injury. Both betamethasone and CsA significantly suppressed IL-1alpha and IL-8 at day 4. Only betamethasone significantly suppressed IL-6 at days 4 and 7. Both agents significantly reduced corneal opacity at day 4.

CONCLUSION

Early systemic administration of betamethasone or CsA after alkali injury may be of benefit by suppressing inflammatory cytokine expression in the cornea.

Pharmacological modulation of interleukin-17-induced GCP-2-, GRO-alpha- and interleukin-8 release in human bronchial epithelial cells

The cytokine interleukin-17 may play a role in the recruitment of airway neutrophils, and interleukin-17 protein is increased in the airways of patients with asthma. In this study, we characterised the effect of interleukin-17 on the release of the neutrophil-recruiting cytokines granulocyte chemotactic protein (GCP)-2, growth-related oncogene (GRO)-alpha and interleukin-8 in human bronchial epithelial (HBE) cells. We also characterised the involvement of mitogen-activated protein (MAP) kinases as well as the effect of beta-adrenoceptor and glucocorticoid receptor stimulation and calcineurin and P-glycoprotein inhibition on these epithelial responses to interleukin-17. We found that interleukin-17 (1-1000 ng/ml) increased the release of GCP-2, GRO-alpha and interleukin-8 in a concentration-dependent manner. This interleukin-17-induced release of C-X-C chemokines was sensitive to inhibition of the p38 MAP kinase pathway and to stimulation of glucocorticoid receptors. In contrast, stimulation of beta-adrenoceptors increased the release of interleukin-8 and did not markedly alter the release of GCP-2 and GRO-alpha. Inhibition of calcineurin and of P-glycoproteins did not exert any substantial effect on the release of C-X-C chemokines. In conclusion, interleukin-17 bears the potential to increase neutrophil recruitment into the airways by releasing several, different C-X-C chemokines, including GCP-2, GRO-alpha and interleukin-8 in human bronchial epithelial cells. Inhibition of the p38 MAP kinase pathway and glucocorticoid receptor stimulation constitute two credible therapeutic strategies against this interleukin-17-induced release of neutrophil-recruiting cytokines.

Proliferative vitreoretinopathy: risk factors and pathobiology

Proliferative vitreoretinopathy (PVR) is still a major cause of failure of retinal detachment surgery. Despite a dramatic increase in our pathobiologic knowledge of PVR during the last 10 years, little of this information has been used to modify the surgical management of the disease, and, thus, the anatomic and functional results are still unsatisfactory. Collaborative research involving clinicians and basic researchers must be encouraged. PVR must be considered a multifactorial disease caused by interaction of several cells and intra- and extraocular factors. Therefore, therapeutic options based on the inhibition of one factor or phenomenon may be regarded with scepticism. To prevent PVR, it is necessary to determine the factors involved in its development, and because of its relatively small prevalence, large, prospective, multicenter studies seem necessary. In addition, clinical research must not be underestimated. PVR affects both sides of the retina and the retina itself, a point to which little attention has been paid and that is critical for surgical results. Therefore, a new classification that provides information about clinical relevance, such as the evolutionary stages of the disease (biologic activity) and the degree of surgical difficulty (location of the fibrotic process), seems necessary.