AZD6738 Inhibits fibrotic response of conjunctival fibroblasts by regulating checkpoint kinase 1/P53 and PI3K/AKT pathways

Pharmacological Stimulation of Soluble Guanylate Cyclase Counteracts the Profibrotic Activation of Human Conjunctival Fibroblasts

Conjunctival fibrosis is a serious clinical concern implicated in a wide spectrum of eye diseases, including outcomes of surgery for pterygium and glaucoma. It is mainly driven by chronic inflammation that stimulates conjunctival fibroblasts to differentiate into myofibroblasts over time, leading to abnormal wound healing and scar formation. Soluble guanylate cyclase (sGC) stimulation was found to suppress transforming growth factor β (TGFβ)-induced myofibroblastic differentiation in various stromal cells such as skin and pulmonary fibroblasts, as well as corneal keratocytes. Here, we evaluated the in vitro effects of stimulation of the sGC enzyme with the cell-permeable pyrazolopyridinylpyrimidine compound BAY 41-2272 in modulating the TGFβ1-mediated profibrotic activation of human conjunctival fibroblasts. Cells were pretreated with the sGC stimulator before challenging with recombinant human TGFβ1, and subsequently assayed for viability, proliferation, migration, invasiveness, myofibroblast marker expression, and contractile properties. Stimulation of sGC significantly counteracted TGFβ1-induced cell proliferation, migration, invasiveness, and acquisition of a myofibroblast-like phenotype, as shown by a significant downregulation of FAP, ACTA2, COL1A1, COL1A2, FN1, MMP2, TIMP1, and TIMP2 mRNA levels, as well as by a significant reduction in α-smooth muscle actin, N-cadherin, COL1A1, and FN-EDA protein expression. In addition, pretreatment with the sGC stimulator was capable of significantly dampening TGFβ1-induced acquisition of a contractile phenotype by conjunctival fibroblasts, as well as phosphorylation of Smad3 and release of the proinflammatory cytokines IL-1β and IL-6. Taken together, our findings are the first to demonstrate the effectiveness of pharmacological sGC stimulation in counteracting conjunctival fibroblast-to-myofibroblast transition, thus providing a promising scientific background to further explore the feasibility of sGC stimulators as potential new adjuvant therapeutic compounds to treat conjunctival fibrotic conditions.

Long non‑coding RNA PEG13 regulates endothelial cell senescence through the microRNA‑195/IRS1 axis

Atherosclerosis is a chronic inflammatory disease characterized by endothelial dysfunction and plaque formation. The present study aimed to elucidate the pathological role of the long non-coding RNA (lncRNA) paternally expressed 13 (PEG13) in the onset and progression of atherosclerosis. Specifically, its effects on human umbilical vein endothelial cell (HUVEC) proliferation, angiogenesis, senescence and senescence-associated secretory phenotype (SASP)-related factors were investigated using cell proliferation, cellular angiogenesis, β-galactosidase staining, reverse transcription-quantitative PCR and enzyme-linked immunosorbent assays. The results showed that oxidized low-density lipoprotein (ox-LDL) inhibited lncRNA PEG13 expression and HUVEC viability in a dose-dependent manner and PEG13 overexpression partially reversed these effects. Additionally, PEG13 overexpression ameliorated the ox-LDL-induced impairment of angiogenesis, cellular senescence and SASP. Furthermore, lncRNA PEG13 directly targeted microRNA (miR/miRNA)-195-5p, suppressing the ox-LDL-induced upregulation of the miRNA. The gene coding for insulin receptor substrate 1 (IRS1), an activator of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, was confirmed as a direct target of miR-195. PEG13 overexpression attenuated the ox-LDL-induced inhibition of IRS1 expression and PI3K/AKT signaling and its protective effects on HUVEC viability, angiogenesis and senescence were partially reversed by small interfering RNAs targeting IRS1. The present study demonstrated that lncRNA PEG13 attenuates ox-LDL-induced senescence in HUVECs by modulating the miR-195/IRS1/PI3K/AKT signaling pathway, suggesting a potential therapeutic target for the treatment of atherosclerosis.

Sulforaphane inhibits TGF-β-induced fibrogenesis and inflammation in human Tenon's fibroblasts

Purpose

Subconjunctival fibrosis is the main cause of failure after glaucoma filtration surgery. We explored the effects of sulforaphane (SFN) on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts, transforming growth factor (TGF)-β-induced contraction of collagen gel, and inflammation.

Methods

After treatment with the combination of TGF-β and SFN or TGF-β alone, primary HTFs were subjected to a three-dimensional collagen contraction experiment to examine their contractility. Levels of α smooth muscle actin (α-SMA), synthesis of extracellular matrix (ECM), and phosphorylation of various signaling molecules were determined by western blot or quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Fluorescence microscopy was employed to examine stress fiber formation in HTFs. The expressions of interleukin (IL)-6, IL-8, and connective tissue growth factor (CTGF) were determined using RT-qPCR.

Results

The contraction of myofibroblasts caused by TGF-β was significantly suppressed by SFN. This suppressive effect was exerted via the differentiation of HTFs into myofibroblasts by inhibiting the production of fibronectin and the expression of α-SMA. Moreover, SFN treatment reduced the expression of TGF-β-promoted integrins β1 and α5, myosin light chain (MLC) phosphorylation, and stress fiber formation, as well as the expression of IL-6, IL-8, and CTGF. Finally, TGF-β-induced Smad2/3 and extracellular signal-regulated kinase (ERK) phosphorylations were attenuated by SFN.

Conclusions

SFN inhibits HTF contractility, differentiation into myofibroblasts, and inflammation caused by TGF-β. These effects are mediated by both classic and non-classic signaling pathways. Our results indicate that SFN has potent anti-fibrotic and anti-inflammatory effects in HTFs and is a potential candidate for subconjunctival fibrosis therapy.