Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells
Background/Aims: High glucose activates spleen tyrosine kinase (Syk) in human proximal tubular epithelial cells (HK-2 cells), which leads to NF-κB activation and transforming growth factor-ß1 (TGF-ß1) production. We explored the signal transduction pathway from high glucose to Syk activatio...
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| Format: | Article |
| Language: | English |
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Cell Physiol Biochem Press GmbH & Co KG
2015-04-01
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| Series: | Cellular Physiology and Biochemistry |
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| Online Access: | http://www.karger.com/Article/FullText/374034 |
| _version_ | 1819011619954360320 |
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| author | Won Seok Yang Joon-Seok Kim Nam Jeong Han Mee Jeong Lee Su-Kil Park |
| author_facet | Won Seok Yang Joon-Seok Kim Nam Jeong Han Mee Jeong Lee Su-Kil Park |
| author_sort | Won Seok Yang |
| collection | DOAJ |
| description | Background/Aims: High glucose activates spleen tyrosine kinase (Syk) in human proximal tubular epithelial cells (HK-2 cells), which leads to NF-κB activation and transforming growth factor-ß1 (TGF-ß1) production. We explored the signal transduction pathway from high glucose to Syk activation. Methods: The pathway was evaluated by siRNA transfection, immunoprecipitation and Western blot. Results: High glucose stimulated Syk activation within 10 min. Depletion of toll-like receptor 4 (TLR4) attenuated high glucose-induced Syk activation, NF-κB p65 nuclear translocation, and TGF-ß1 production. In addition, TLR4 inhibitor (CLI-095), TLR4-neutralizing antibody, and depletion of myeloid differentiation factor 88 (MyD88) all attenuated high glucose-induced Syk activation. As an evidence of TLR4 activation, interleukin-1 receptor-associated kinase 1 was recruited to MyD88 and TLR4 upon exposure to high glucose. Syk was co-immunoprecipitated with TLR4, and Syk bound to TLR4 was activated by high glucose. High-mobility group box-1 (HMGB-1), an endogenous activator of TLR4, rapidly increased in TLR4 immunoprecipitates upon high glucose stimulation, and this association was reduced by N-acetylcysteine, an antioxidant. An HMGB-1 inhibitor glycyrrhizin suppressed high glucose-induced Syk activation. Conclusion: Syk is constitutively associated with TLR4. High glucose induces an immediate, reactive oxygen species-dependent, extracellular release of HMGB-1 which binds to TLR4 and activates it, leading to Syk activation. |
| first_indexed | 2024-12-21T01:31:03Z |
| format | Article |
| id | doaj.art-f6f0a3cf00644104b22b1373a77c5875 |
| institution | Directory Open Access Journal |
| issn | 1015-8987 1421-9778 |
| language | English |
| last_indexed | 2024-12-21T01:31:03Z |
| publishDate | 2015-04-01 |
| publisher | Cell Physiol Biochem Press GmbH & Co KG |
| record_format | Article |
| series | Cellular Physiology and Biochemistry |
| spelling | doaj.art-f6f0a3cf00644104b22b1373a77c58752022-12-21T19:20:22ZengCell Physiol Biochem Press GmbH & Co KGCellular Physiology and Biochemistry1015-89871421-97782015-04-013562309231910.1159/000374034374034Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial CellsWon Seok YangJoon-Seok KimNam Jeong HanMee Jeong LeeSu-Kil ParkBackground/Aims: High glucose activates spleen tyrosine kinase (Syk) in human proximal tubular epithelial cells (HK-2 cells), which leads to NF-κB activation and transforming growth factor-ß1 (TGF-ß1) production. We explored the signal transduction pathway from high glucose to Syk activation. Methods: The pathway was evaluated by siRNA transfection, immunoprecipitation and Western blot. Results: High glucose stimulated Syk activation within 10 min. Depletion of toll-like receptor 4 (TLR4) attenuated high glucose-induced Syk activation, NF-κB p65 nuclear translocation, and TGF-ß1 production. In addition, TLR4 inhibitor (CLI-095), TLR4-neutralizing antibody, and depletion of myeloid differentiation factor 88 (MyD88) all attenuated high glucose-induced Syk activation. As an evidence of TLR4 activation, interleukin-1 receptor-associated kinase 1 was recruited to MyD88 and TLR4 upon exposure to high glucose. Syk was co-immunoprecipitated with TLR4, and Syk bound to TLR4 was activated by high glucose. High-mobility group box-1 (HMGB-1), an endogenous activator of TLR4, rapidly increased in TLR4 immunoprecipitates upon high glucose stimulation, and this association was reduced by N-acetylcysteine, an antioxidant. An HMGB-1 inhibitor glycyrrhizin suppressed high glucose-induced Syk activation. Conclusion: Syk is constitutively associated with TLR4. High glucose induces an immediate, reactive oxygen species-dependent, extracellular release of HMGB-1 which binds to TLR4 and activates it, leading to Syk activation.http://www.karger.com/Article/FullText/374034High glucoseHigh-mobility group box-1MyD88Spleen tyrosine kinaseToll-like receptor 4Transforming growth factor-β1 |
| spellingShingle | Won Seok Yang Joon-Seok Kim Nam Jeong Han Mee Jeong Lee Su-Kil Park Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells Cellular Physiology and Biochemistry High glucose High-mobility group box-1 MyD88 Spleen tyrosine kinase Toll-like receptor 4 Transforming growth factor-β1 |
| title | Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells |
| title_full | Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells |
| title_fullStr | Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells |
| title_full_unstemmed | Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells |
| title_short | Toll-Like Receptor 4/Spleen Tyrosine Kinase Complex in High Glucose Signal Transduction of Proximal Tubular Epithelial Cells |
| title_sort | toll like receptor 4 spleen tyrosine kinase complex in high glucose signal transduction of proximal tubular epithelial cells |
| topic | High glucose High-mobility group box-1 MyD88 Spleen tyrosine kinase Toll-like receptor 4 Transforming growth factor-β1 |
| url | http://www.karger.com/Article/FullText/374034 |
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