Increased Levels of Catalase and Cathepsin V/L2 but Decreased TIMP-1 in Keratoconus Corneas: Evidence that Oxidative Stress Plays a Role in This Disorder

Kenney, M. Cristina; Chwa, Marilyn; Atilano, Shari R.; Tran, Annie; Carballo, Marilee; Saghizadeh, Mehrnoosh; Vasiliou, Vasilis; Adachi, Wakako; Brown, Donald J.

doi:10.1167/iovs.04-0549

Cited by 172 publications

(152 citation statements)

References 63 publications

(71 reference statements)

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“…19 -21 Our previous study found a twofold increase in levels of catalase RNA and activity in KC corneas compared with age-matched normal corneas. 22 Because catalase is the major antioxidant enzyme functioning to eliminate H 2 O 2 , 19 -21 these findings imply elevated levels of H 2 O 2 within KC corneas. The consequences of increased H 2 O 2 levels within the cornea or corneal cell cultures are not known.…”

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confidence: 99%

“…[27][28][29][30][31] We wanted to determine the effect(s) of a H 2 O 2 challenge on normal and KC fibroblasts in vitro, including the effects on catalase levels, which are increased in intact KC corneas. 22 There are significant relationships among oxidative stress, ROS/RNS elements, and mitochondria. The accumulation of ROS/RNS can cause a vicious cycle of damage to the mtDNA, leading to mitochondrial dysfunction, decreased oxidative phosphorylation (OXPHOS) and increased ROS/RNS production.…”

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confidence: 99%

“…40 The triad of mitochondrial dysfunction, ROS production, and oxidative stress may play a role in the pathogenesis of KC. 22,40 In the present investigation, we examined whether one element of this triad, that is ROS production, is abnormal in KC fibroblast cultures. Our working hypothesis was that KC fibroblasts have an elevated ROS/RNS burden and, as a result, are more susceptible to stress-related challenges.…”

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confidence: 99%

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Increased Stress-Induced Generation of Reactive Oxygen Species and Apoptosis in Human Keratoconus Fibroblasts

Chwa

Atilano

Reddy

et al. 2006

Invest. Ophthalmol. Vis. Sci.

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138

124

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PURPOSE.To determine whether keratoconus (KC) corneal fibroblast cultures have increased reactive oxygen species (ROS) production and are more susceptible to stress-related challenges. METHODS. Normal (n ϭ 9) and KC (n ϭ 10) stromal fibroblast cultures were incubated in either neutral-or low-pH conditions, with or without hydrogen peroxide. Catalase activities were measured with a fluorescent substrate assay. Superoxide and ROS/reactive nitrogen species (RNS) productions were determined with an amine-reactive green-dye assay and 2Ј,7Ј-dichlorodihydrofluorescein diacetate (H 2 DCFDA) dye assay, respectively. Cell viability was analyzed by a dye-exclusion assay. Caspase 3 activity was measured by a fluorochrome inhibitor of caspase (FLICA) assay. A cationic (green) dye was used to measure the mitochondrial membrane potential (⌬⌿m). RESULTS. KC fibroblasts had increased superoxide and ROS/RNS production (6.2-fold, P Ͻ 0.001 and 1.8-fold, P Ͻ 0.001, respectively) and catalase activity (P Ͻ 0.01) with higher concentrations of H 2 O 2 compared with normal cultures (P ϭ 0.16). After a low-pH stress challenge, KC fibroblasts maintained higher ROS/RNS levels (3.3-fold, P Ͻ 0.02), showed higher caspase-3 activity (7.5-fold, P Ͻ 0.02) and decreased ⌬⌿m (2.6-fold, P Ͻ 0.04), and had decreased cell viability (37%, P Ͻ 0.005 vs. 20%, P Ͻ 0.27) compared with normal fibroblasts. CONCLUSIONS. Under identical conditions, KC fibroblasts had increased basal generation of ROS/RNS and were more susceptible to stressful challenges (low-pH and/or H 2 O 2 conditions) than were normal fibroblasts. In addition, the stressed KC fibroblasts possessed characteristics similar to those found in the intact KC corneas (increased catalase activity, ROS production, and apoptosis). These properties may play a role in the pathogenesis of KC. (Invest Ophthalmol Vis Sci.

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Increased Stress-Induced Generation of Reactive Oxygen Species and Apoptosis in Human Keratoconus Fibroblasts

Chwa

Atilano

Reddy

et al. 2006

Invest. Ophthalmol. Vis. Sci.

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138

124

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“…MMP-1, -2, -7, -9, -14, TIMP-2 and TIMP-3 mRNA levels did not differ between normal and keratoconic corneas 52 . There was, however, a 1.8 fold decrease in TIMP-1 mRNA and 2.8 fold decrease in TIMP-1 protein in keratoconus 52 .…”

Section: Whole Cornea Studies and Decreased Timp-1mentioning

confidence: 70%

Keratoconus Layer by Layer - Pathology and Matrix Metalloproteinases

Nelidova¹,

Sherwin²

2012

Advances in Ophthalmology

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“…MMP-1, -2, -3, -7, -9 and -13 have been found to be elevated in the tear film of patients with keratoconus (22)(23)(24)(25)43,44) and decreased levels of TIMP-1 have been found in keratoconus corneas and their cell cultures (6,45), indicating that MMPs and TIMPs may be involved in the pathogenesis of keratoconus. Our studies have focused primarily on MMP-1, MMP-3, TIMP-1, and TIMP-2.…”

Section: Discussionmentioning

confidence: 99%

Induction of MMP-1 and −3 by cyclical mechanical stretch is mediated by IL-6 in cultured fibroblasts of keratoconus

Du¹,

Chen²,

Li³

et al. 2017

Molecular Medicine Reports

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Abstract. In order to understand the effect of mechanical stretch on corneal extracellular matrix remodeling, human keratoconus fibroblasts (HKCFBs) were subjected to cyclic stretch in vitro and the expression of matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), and inflammatory cytokines were evaluated. HKCFBs were seeded into a flexible membrane base and subjected to a cyclic stretch regimen of 10% equibiaxial stretch at a stretching frequency of 1 Hz for 6 h using a Flexcell tension unit. An antibody directed against interleukin-6 (IL-6 Ab) was used to investigate the roles of IL-6 on mechanical stretch mediated regulation of MMP in HKCFBs. Culture supernatants were assayed using an enzyme-linked immunosorbent assay for MMP-1 and -3, TIMP-1 and -2, and IL-6. Total RNA from the cells was extracted, and quantitative polymerase chain reaction was used to determine mRNA for MMP-1 and -3, TIMP-1 and -2, and IL-6. In stretched cells, levels of MMP-1 and -3 demonstrated an increase compared with unstretched cells, but levels of TIMP-1, and -2 revealed a decrease. Mechanical stretch significantly increased the mRNA expression and protein synthesis of IL-6 compared with unstretched cells. IL-6 induced MMP-1 and -3 expression, whereas no significant effects were observed in levels of TIMP-1 and -2 compared with the untreated control groups. Additionally, the IL-6 Ab markedly inhibited the stretch-induced increase in MMP-1 and -3 in culture supernatants in a dose-dependent manner. No significant differences in TIMP-1 and -2 protein levels were detected between stretched cells treated with IL-6 Ab and stretched cells without IL-6 Ab treatment. These results indicate that cyclical mechanical stretch augments IL-6 production and MMP expression, and reduces levels of TIMP in HKCFBs. Thus, it is suggested that IL-6 mediates the stretch-induced MMP expression.

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Increased Levels of Catalase and Cathepsin V/L2 but Decreased TIMP-1 in Keratoconus Corneas: Evidence that Oxidative Stress Plays a Role in This Disorder

Cited by 172 publications

References 63 publications

Increased Stress-Induced Generation of Reactive Oxygen Species and Apoptosis in Human Keratoconus Fibroblasts

Increased Stress-Induced Generation of Reactive Oxygen Species and Apoptosis in Human Keratoconus Fibroblasts

Keratoconus Layer by Layer - Pathology and Matrix Metalloproteinases

Induction of MMP-1 and −3 by cyclical mechanical stretch is mediated by IL-6 in cultured fibroblasts of keratoconus

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