TY - JOUR
T1 - Expression of optineurin isolated from rat-injured dental pulp and the effects on inflammatory signals in normal rat kidney cells
AU - Senoo, Kyoko
AU - Yamashiro, Keisuke
AU - Yamamoto, Tadashi
AU - Myokai, Fumio
AU - Kawamura, Mari
AU - Takashiba, Shogo
PY - 2018/4/1
Y1 - 2018/4/1
N2 - We previously isolated rat 14.7K-interacting protein-2 (rFIP-2) from the rat-wounded pulp. The protein, homologous to human FIP-2, is known as optineurin and was initially identified as a novel tumor necrosis factor-α (TNF-α)-inducible protein, and more recently, as an autophagy receptor. However, the biological role of optineurin in dental pulp remains elusive. We hypothesized that optineurin has a crucial role in regulating molecular processes during pulp inflammatory responses induced by TNF-α. We examined the kinetics of optineurin expression in pulp inflammation. Optineurin localization and expression were examined using rat pulp fibroblasts. The cells were treated with pharmacological inhibitors for TNF-α-induced inflammatory signals or with hydrogen peroxide as apoptotic stimuli. Stable optineurin-knockdown cells (OPTN-KD cells) were established by transfecting normal rat kidney cells with a vector expressing optineurin-specific small interfering RNA. Cell proliferation and the profiles of cytokines and intracellular signaling molecules were examined using OPTN-KD cells stimulated by TNF-α. Optineurin was localized in the cytoplasm and then translocated into the nucleus upon apoptotic stimuli. Optineurin expression was increased by TNF-α and decreased by a specific inhibitor of c-Jun N-terminal kinase. The OPTN-KD cells secreted smaller amounts of monocyte chemotactic protein-1 (MCP-1) and intracellular MCP-1 mRNA, and cell proliferation was significantly increased. Apoptosis-related signaling molecules were downregulated in OPTN-KD cells. These results demonstrated that optineurin is a crucial molecule mediated by TNF-α, which induces the production of inflammatory factors and apoptosis signaling, suggesting the presence of signaling interactions between optineurin and a transcription factor for MCP-1.
AB - We previously isolated rat 14.7K-interacting protein-2 (rFIP-2) from the rat-wounded pulp. The protein, homologous to human FIP-2, is known as optineurin and was initially identified as a novel tumor necrosis factor-α (TNF-α)-inducible protein, and more recently, as an autophagy receptor. However, the biological role of optineurin in dental pulp remains elusive. We hypothesized that optineurin has a crucial role in regulating molecular processes during pulp inflammatory responses induced by TNF-α. We examined the kinetics of optineurin expression in pulp inflammation. Optineurin localization and expression were examined using rat pulp fibroblasts. The cells were treated with pharmacological inhibitors for TNF-α-induced inflammatory signals or with hydrogen peroxide as apoptotic stimuli. Stable optineurin-knockdown cells (OPTN-KD cells) were established by transfecting normal rat kidney cells with a vector expressing optineurin-specific small interfering RNA. Cell proliferation and the profiles of cytokines and intracellular signaling molecules were examined using OPTN-KD cells stimulated by TNF-α. Optineurin was localized in the cytoplasm and then translocated into the nucleus upon apoptotic stimuli. Optineurin expression was increased by TNF-α and decreased by a specific inhibitor of c-Jun N-terminal kinase. The OPTN-KD cells secreted smaller amounts of monocyte chemotactic protein-1 (MCP-1) and intracellular MCP-1 mRNA, and cell proliferation was significantly increased. Apoptosis-related signaling molecules were downregulated in OPTN-KD cells. These results demonstrated that optineurin is a crucial molecule mediated by TNF-α, which induces the production of inflammatory factors and apoptosis signaling, suggesting the presence of signaling interactions between optineurin and a transcription factor for MCP-1.
KW - Apoptosis
KW - Dental pulp
KW - FIP-2
KW - Inflammation
KW - Optineurin
UR - http://www.scopus.com/inward/record.url?scp=85026819196&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85026819196&partnerID=8YFLogxK
U2 - 10.1007/s10266-017-0314-5
DO - 10.1007/s10266-017-0314-5
M3 - Article
C2 - 28776281
AN - SCOPUS:85026819196
VL - 106
SP - 135
EP - 144
JO - Odontology / the Society of the Nippon Dental University
JF - Odontology / the Society of the Nippon Dental University
SN - 1618-1247
IS - 2
ER -