The role of focal adhesion kinase in transforming growth factor-β2 induced migration of human lens epithelial cells

Radiation-Induced Alterations in Proliferation, Migration, and Adhesion in Lens Epithelial Cells and Implications for Cataract Development

The lens of the eye is one of the most radiosensitive tissues. Although the exact mechanism of radiation-induced cataract development remains unknown, altered proliferation, migration, and adhesion have been proposed as factors. Lens epithelial cells were exposed to X-rays (0.1-2 Gy) and radiation effects were examined after 12 h and 7 day. Proliferation was quantified using an MTT assay, migration was measured using a Boyden chamber and wound-healing assay, and adhesion was assessed on three extracellular matrices. Transcriptional changes were also examined using RT-qPCR for a panel of genes related to these processes. In general, a nonlinear radiation response was observed, with the greatest effects occurring at a dose of 0.25 Gy. At this dose, a reduction in proliferation occurred 12 h post irradiation (82.06 ± 2.66%), followed by an increase at 7 day (116.16 ± 3.64%). Cell migration was increased at 0.25 Gy, with rates 121.66 ± 6.49% and 232.78 ± 22.22% greater than controls at 12 h and 7 day respectively. Cell adhesion was consistently reduced above doses of 0.25 Gy. Transcriptional alterations were identified at these same doses in multiple genes related to proliferation, migration, and adhesion. Overall, this research began to elucidate the functional changes that occur in lens cells following radiation exposure, thereby providing a better mechanistic understanding of radiation-induced cataract development.

Fibronectin has multifunctional roles in posterior capsular opacification (PCO)

Fibrotic posterior capsular opacification (PCO), one of the major complications of cataract surgery, occurs when lens epithelial cells (LCs) left behind post cataract surgery (PCS) undergo epithelial to mesenchymal transition, migrate into the optical axis and produce opaque scar tissue. LCs left behind PCS robustly produce fibronectin, although its roles in fibrotic PCO are not known. In order to determine the function of fibronectin in PCO pathogenesis, we created mice lacking the fibronectin gene (FN conditional knock out -FNcKO) from the lens. While animals from this line have normal lenses, upon lens fiber cell removal which models cataract surgery, FNcKO LCs exhibit a greatly attenuated fibrotic response from 3 days PCS onward as assessed by a reduction in surgery-induced cell proliferation, and fibrotic extracellular matrix (ECM) production and deposition. This is correlated with less upregulation of Transforming Growth Factor β (TGFβ) and integrin signaling in FNcKO LCs PCS concomitant with sustained Bone Morphogenetic Protein (BMP) signaling and elevation of the epithelial cell marker E cadherin. Although the initial fibrotic response of FNcKO LCs was qualitatively normal at 48 h PCS as measured by the upregulation of fibrotic marker protein αSMA, RNA sequencing revealed that the fibrotic response was already quantitatively attenuated at this time, as measured by the upregulation of mRNAs encoding molecules that control, and are controlled by, TGFβ signaling, including many known markers of fibrosis. Most notably, gremlin-1, a known regulator of TGFβ superfamily signaling, was upregulated sharply in WT LCs PCS, while this response was attenuated in FNcKO LCs. As exogenous administration of either active TGFβ1 or gremlin-1 to FNcKO lens capsular bags rescued the attenuated fibrotic response of fibronectin null LCs PCS including the loss of SMAD2/3 phosphorylation, this suggests that fibronectin plays multifunctional roles in fibrotic PCO development.

Interleukin-2 induces extracellular matrix synthesis and TGF-β2 expression in retinal pigment epithelial cells

Macular fibrosis is a vital obstacle of vision acuity improvement of age‐related macular degeneration patients. This study was to investigate the effects of interleukin 2 (IL‐2) on epithelial‐mesenchymal transition (EMT), extracellular matrix (ECM) synthesis and transforming growth factor β2 (TGF‐β2) expression in retinal pigment epithelial (RPE) cells. 10 μg/L IL‐2 was used to induce fibrosis in RPE cells for various times. Western blot was used to detect the EMT marker α‐smooth muscle actin (α‐SMA), ECM markers fibronectin (Fn) and type 1 collagen (COL‐1), TGF‐β2, and the activation of the JAK/STAT3 and NF‐κB signaling pathway. Furthermore, JAK/STAT3 and NF‐κB signaling pathways were specifically blocked by WP1066 or BAY11‐7082, respectively, and the expression of α‐SMA, COL‐1, Fn and TGF‐β2 protein were detected. Wound healing and Transwell assays were used to measure cell migration ability of IL‐2 with or without WP1066 or BAY11‐7082. After induction of IL‐2, the expressions of Fn, COL‐1, TGF‐β2 protein were significantly increased, and this effect was correlated with IL‐2 treatment duration, while α‐SMA protein expression did not change significantly. Both WP1066 and BAY11‐7082 could effectively downregulate the expression of Fn, COL‐1 and TGF‐β2 induced by IL‐2. What's more, both NF‐κB and JAK/STAT3 inhibitors could suppress the activation of the other signaling pathway. Additionally, JAK/STAT3 inhibitor WP1066 and NF‐κB inhibitor BAY 11‐7082 could obviously decrease RPE cells migration capability induced by IL‐2. IL‐2 promotes cell migration, ECM synthesis and TGF‐β2 expression in RPE cells via JAK/STAT3 and NF‐κB signaling pathways, which may play an important role in proliferative vitreoretinopathy.

LncRNA FEZF1-AS1 Promotes TGF-β2-Mediated Proliferation and Migration in Human Lens Epithelial Cells SRA01/04

Posterior capsule opacification (PCO) is a common complication after cataract surgery attributed to the proliferation and migration of postoperative residual lens epithelial cells (LECs). The long noncoding RNA (lncRNA) FEZ family zinc finger 1 antisense RNA 1 (FEZF1-AS1) promotes the proliferation and migration of multiple types of cancer cells. Here, we discovered that FEZF1-AS1 is markedly upregulated in TGF-β2-treated SRA01/04 cells. In addition, the proliferation and migration of SRA01/04 cells were enhanced following TGF-β2 treatment. FEZF1-AS1 knockdown inhibited the TGF-β2-induced proliferation and migration of SRA01/04 cells. Accordingly, FEZF1-AS1 overexpression promoted the TGF-β2-induced proliferation and migration of SRA01/04 cells. Finally, FEZF1-AS1 upregulated TGF-β2-induced SRA01/04 cell proliferation and migration via boosting FEZF1 protein levels. Our findings indicate that the dysregulation of FEZF1-AS1 participates in the TGF-β2-induced proliferation and migration of human lens epithelial cells (HLECs), which might be achieved, at least in part, through the induction of FEZF1 expression.