High mobility group B1 up-regulates angiogenic and fibrogenic factors in human retinal pigment epithelial ARPE-19 cells

• Published in: Cellular signalling Vol. 40; pp. 248 - 257
• Main Authors: Chang, Yo-Chen, Lin, Chia-Wei, Hsieh, Ming-Chu, Wu, Horng-Jiun, Wu, Wen-Sheng, Wu, Wen-Chuan, Kao, Ying-Hsien
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01.12.2017
• Subjects: Angiogenesis; Angiogenesis Inducing Agents - metabolism; Autocrine Communication - genetics; Cell Hypoxia - drug effects; Cell Hypoxia - genetics; Cell Proliferation - drug effects; Cobalt - administration & dosage; Diabetic Retinopathy - drug therapy; Diabetic Retinopathy - genetics; Diabetic Retinopathy - pathology; Gene Expression Regulation, Developmental - drug effects; HMGB1 Protein - administration & dosage; HMGB1 Protein - genetics; HMGB1 Protein - metabolism; Humans; Hypoxia; p38 Mitogen-Activated Protein Kinases - genetics; Peptides - administration & dosage; Peptides - genetics; Peptides - metabolism; RAGE; Retinal Pigment Epithelium - drug effects; Retinal Pigment Epithelium - metabolism; Signal transduction; Signal Transduction - drug effects; Tissue remodeling; TLR4; Angiogenesis; Signal transduction; Hypoxia; RAGE; TLR4; Tissue remodeling
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2017.09.019

Hypoxia-induced retinal neovascularization plays a central role in the pathogenesis of diabetic retinopathy. This study aimed to investigate whether hypoxia leads to the release of nuclear high mobility group box 1 (HMGB1) peptides from cultured retinal pigment epithelial ARPE-19 cells, to determine the effect of HMGB1 on angiogenic cytokine production and elucidate the involved signaling pathways. A chemical hypoxia mimetic agent, cobalt chloride, induced SIRT1 downregulation, HMGB1 nucleocytoplasmic relocation and extracellular release from ARPE-19 cells, implicating its autocrine function. Resveratrol treatment significantly reduced secretion of HMGB1 from ARPE-19 cells exposed to hypoxia. Cell proliferation and cell cycle analyses demonstrated that exogenous HMGB1 caused significant growth suppression and G1 cell cycle arrest in ARPE-19 cells. Morphological observations showed that HMGB1 enhanced adhesion, but suppressed migration of ARPE-19 cells. More intriguingly, HMGB1 up-regulated expression of angiofibrogenic factors in ARPE-19 cells, including VEGF, bFGF, TGF-β2, and CTGF. Signal profiling characterization indicated that HMGB1 triggered hyperphosphorylation of Akt, p38 MAPK, and NF-κB, but not that of ERK, JNK, and Smad2, whereas inhibition of PI3K, MAPK, or NF-κB significantly attenuated the HMGB1-driven cytokine overproduction in ARPE-19 cells. Functional neutralization with anti-TLR4 and -RAGE antibodies confirmed that both receptors were involved in the cytokine overproduction. In conclusion, chemically-mimicked hypoxia induced nucleocytoplasmic relocation and release of HMGB1 peptides, which in turn up-regulated the production of angiofibrogenic factors in RPE cells, thereby contributing to the pathogenesis of hypoxia-associated diabetic retinopathies. Conversely, blockades of intraocular HMGB1 bioavailability or signal activation may prevent angiofibrogenesis in development of diabetic retinopathy. [Display omitted] •CoCl2 mobilizes nuclear HMGB1 and induces its release from ARPE-19 cells.•HMGB1 up-regulates angiogenic and fibrogenic factor expression in ARPE-19 cells.•HMGB1 exerts MMP activation and tissue remodeling effect.•HMGB1 triggers hyperphosphorylation of Akt, p38 MAPK, and NF-κB.•Both TLR4 and RAGE receptors are involved in HMGB1-induced cytokine overproduction.