The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes
Keratinocytes can be activated by Cutibacterium acnes, leading to the production of proinflammatory cytokines via toll-like receptors (TLRs) 2 and 4. Although several studies have investigated keratinocytes, the mechanism of calcium-mediated activation remains unclear. Herein, we investigated whethe...
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| Format: | Article |
| Language: | English |
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Wiley
2024-01-01
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| Series: | Mediators of Inflammation |
| Online Access: | http://dx.doi.org/10.1155/mi/8892514 |
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| author | Eun-Ok Kim Dain Park In Jin Ha Se-Eun Bae Min Young Lee Miyong Yun Kyuseok Kim |
| author_facet | Eun-Ok Kim Dain Park In Jin Ha Se-Eun Bae Min Young Lee Miyong Yun Kyuseok Kim |
| author_sort | Eun-Ok Kim |
| collection | DOAJ |
| description | Keratinocytes can be activated by Cutibacterium acnes, leading to the production of proinflammatory cytokines via toll-like receptors (TLRs) 2 and 4. Although several studies have investigated keratinocytes, the mechanism of calcium-mediated activation remains unclear. Herein, we investigated whether calcium influx via TLR2 and TLR4 stimulation was involved in cytokine secretion by keratinocytes in HaCaT cells. Although TLR2 stimulation by peptidoglycan (PGN) increased intracellular calcium influx, TLR4 stimulation by lipopolysaccharide (LPS) did not increase it, as analyzed using flow cytometry with the calcium indicator Fluo-3. However, activation by either TLR2 or TLR4 ligands upregulated the intracellular calcium influx in THP-1 monocytes. Additionally, the expression of major proinflammatory cytokines and chemokines, such as interleukin (IL)-6, IL-8, IL-1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1), was significantly increased by TLR2 in HaCaT cells. Moreover, treatment with the intracellular calcium chelator, BAPTA-AM, disrupted PGN-mediated induction of IL-6, IL-8, and MCP-1 production. Real-time quantitative polymerase chain reaction (PCR) and western blotting revealed that TLR2 stimulation induced expression of the epidermal differentiation marker keratin 1. In conclusion, TLR2-induced intracellular calcium influx plays a pivotal role in the secretion of proinflammatory cytokines, such as IL-6 and MCP-1, in keratinocytes. Moreover, the continuous influx of calcium via TLR2 activation leads to keratinization. In vitro studies using HaCaT cells provide basic research on the effect of TLR2-induced calcium on C. acnes-mediated inflammation in keratinocytes. These studies are limited in their ability to clinically predict what happens in human keratinocytes. Clinical studies on patients with acne, including three-dimensional (3D) cultures of primary keratinocytes, are required to develop new diagnostic markers for determining the severity of acne vulgaris. |
| format | Article |
| id | doaj-art-7e5829079e05418da47b447ebe8041f3 |
| institution | Kabale University |
| issn | 1466-1861 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Mediators of Inflammation |
| spelling | doaj-art-7e5829079e05418da47b447ebe8041f32024-11-24T00:00:03ZengWileyMediators of Inflammation1466-18612024-01-01202410.1155/mi/8892514The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in KeratinocytesEun-Ok Kim0Dain Park1In Jin Ha2Se-Eun Bae3Min Young Lee4Miyong Yun5Kyuseok Kim6Medical Science Research CenterKorean Medicine Clinical Trial CenterKorean Medicine Clinical Trial CenterDepartment of AnatomyKorean Medicine Clinical Trial CenterDepartment of Bioindustry and Bioresource EngineeringDepartment of OphthalmologyKeratinocytes can be activated by Cutibacterium acnes, leading to the production of proinflammatory cytokines via toll-like receptors (TLRs) 2 and 4. Although several studies have investigated keratinocytes, the mechanism of calcium-mediated activation remains unclear. Herein, we investigated whether calcium influx via TLR2 and TLR4 stimulation was involved in cytokine secretion by keratinocytes in HaCaT cells. Although TLR2 stimulation by peptidoglycan (PGN) increased intracellular calcium influx, TLR4 stimulation by lipopolysaccharide (LPS) did not increase it, as analyzed using flow cytometry with the calcium indicator Fluo-3. However, activation by either TLR2 or TLR4 ligands upregulated the intracellular calcium influx in THP-1 monocytes. Additionally, the expression of major proinflammatory cytokines and chemokines, such as interleukin (IL)-6, IL-8, IL-1α, granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein-1 (MCP-1), was significantly increased by TLR2 in HaCaT cells. Moreover, treatment with the intracellular calcium chelator, BAPTA-AM, disrupted PGN-mediated induction of IL-6, IL-8, and MCP-1 production. Real-time quantitative polymerase chain reaction (PCR) and western blotting revealed that TLR2 stimulation induced expression of the epidermal differentiation marker keratin 1. In conclusion, TLR2-induced intracellular calcium influx plays a pivotal role in the secretion of proinflammatory cytokines, such as IL-6 and MCP-1, in keratinocytes. Moreover, the continuous influx of calcium via TLR2 activation leads to keratinization. In vitro studies using HaCaT cells provide basic research on the effect of TLR2-induced calcium on C. acnes-mediated inflammation in keratinocytes. These studies are limited in their ability to clinically predict what happens in human keratinocytes. Clinical studies on patients with acne, including three-dimensional (3D) cultures of primary keratinocytes, are required to develop new diagnostic markers for determining the severity of acne vulgaris.http://dx.doi.org/10.1155/mi/8892514 |
| spellingShingle | Eun-Ok Kim Dain Park In Jin Ha Se-Eun Bae Min Young Lee Miyong Yun Kyuseok Kim The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes Mediators of Inflammation |
| title | The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes |
| title_full | The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes |
| title_fullStr | The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes |
| title_full_unstemmed | The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes |
| title_short | The Secretion of Inflammatory Cytokines Triggered by TLR2 Through Calcium-Dependent and Calcium-Independent Pathways in Keratinocytes |
| title_sort | secretion of inflammatory cytokines triggered by tlr2 through calcium dependent and calcium independent pathways in keratinocytes |
| url | http://dx.doi.org/10.1155/mi/8892514 |
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