RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis
Abstract Background Nuclear factor κB (NF-κB) activity is a central component of inflammatory and innate immune responses, which plays a crucial role in sepsis. The inhibition of NF-κB signaling and the IκB kinase (IKK) complex is important for understanding the control of innate immunity and regula...
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| Format: | Article |
| Language: | English |
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BMC
2025-06-01
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| Series: | Cell Communication and Signaling |
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| Online Access: | https://doi.org/10.1186/s12964-025-02278-w |
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| author | Shu-jie Pang Tian-yi Jiang Nai-guo Wang Xiao-wen Cui Hui Wang Yu-fei Pan Ning Yang Li-wei Dong |
| author_facet | Shu-jie Pang Tian-yi Jiang Nai-guo Wang Xiao-wen Cui Hui Wang Yu-fei Pan Ning Yang Li-wei Dong |
| author_sort | Shu-jie Pang |
| collection | DOAJ |
| description | Abstract Background Nuclear factor κB (NF-κB) activity is a central component of inflammatory and innate immune responses, which plays a crucial role in sepsis. The inhibition of NF-κB signaling and the IκB kinase (IKK) complex is important for understanding the control of innate immunity and regulating the progress of sepsis. Methods We constructed transgenic mouse strains (Rmp f/f ; Lyz2-Cre + ), and then established lipopolysaccharide (LPS), cecal ligation and perforation (CLP)-induced sepsis models. Hematoxylin-eosin (HE) staining, ELISA, and flow cytometry assay were employed to evaluate the sepsis-related damage and the activation of the inflammatory-related signaling pathway. In vitro, differential expression of RMP cell lines and primary macrophage isolated from transgenic mice were utilized to assess the activation of the NF-κB signaling pathway by Western blot (WB), reverse transcription-polymerase chain reaction (RT-PCR), and ELISA tests. Co‑immunoprecipitation (Co-IP), WB, GST-pulldown, phosphorylation mass spectrometry, surface plasmon resonance (SPR), and IKK activity detection assay were employed to investigate the underlying molecular mechanism by which RMP restrains IKK-NF-κB pathway. Results We identified RNA polymerase II subunit 5 (RPB5)-mediating protein (RMP) as an inhibitor of the IKK complex, which thus inhibited NF-κB signaling in macrophages. In resting macrophages, RMP was directly bound to the kinase domain of IKKβ and inhibited its activity by recruiting protein phosphatase 2 A (PP2A) to the IKK complex. When mouse macrophages were treated with LPS, a Toll-like receptor 4 (TLR4) agonist that stimulates NF-κB signaling, RMP was phosphorylated by IKKβ at Ser439 and dissociated from the IKK complex, which further activated NF-κB signaling. Macrophage-specific deletion of Rmp reduced survival in mice due to an increased inflammatory response in experimental models of sepsis. Conclusions RMP inhibits TLR4-induced NF-κB activation and exerts homeostatic control of innate immunity, and may be promising as a therapeutic target in the limiting of NF-κB signaling and attenuating sepsis-related damage. |
| format | Article |
| id | doaj-art-2c4ac83b622c4d3499bc8bca60a3f2f2 |
| institution | Kabale University |
| issn | 1478-811X |
| language | English |
| publishDate | 2025-06-01 |
| publisher | BMC |
| record_format | Article |
| series | Cell Communication and Signaling |
| spelling | doaj-art-2c4ac83b622c4d3499bc8bca60a3f2f22025-08-20T03:45:32ZengBMCCell Communication and Signaling1478-811X2025-06-0123112010.1186/s12964-025-02278-wRNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsisShu-jie Pang0Tian-yi Jiang1Nai-guo Wang2Xiao-wen Cui3Hui Wang4Yu-fei Pan5Ning Yang6Li-wei Dong7Department of Surgery, Eastern Hepatobiliary Surgery Hospital, the Naval Medical UniversityInternational Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical UniversityDepartment of Spinal Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityNational Center for Liver CancerDepartment of Liver Medicine, Eastern Hepatobiliary Surgery Hospital, the Naval Medical UniversityInternational Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical UniversityDepartment of Surgery, Eastern Hepatobiliary Surgery Hospital, the Naval Medical UniversityInternational Cooperation Laboratory on Signal Transduction, Eastern Hepatobiliary Surgery Institute, the Naval Medical UniversityAbstract Background Nuclear factor κB (NF-κB) activity is a central component of inflammatory and innate immune responses, which plays a crucial role in sepsis. The inhibition of NF-κB signaling and the IκB kinase (IKK) complex is important for understanding the control of innate immunity and regulating the progress of sepsis. Methods We constructed transgenic mouse strains (Rmp f/f ; Lyz2-Cre + ), and then established lipopolysaccharide (LPS), cecal ligation and perforation (CLP)-induced sepsis models. Hematoxylin-eosin (HE) staining, ELISA, and flow cytometry assay were employed to evaluate the sepsis-related damage and the activation of the inflammatory-related signaling pathway. In vitro, differential expression of RMP cell lines and primary macrophage isolated from transgenic mice were utilized to assess the activation of the NF-κB signaling pathway by Western blot (WB), reverse transcription-polymerase chain reaction (RT-PCR), and ELISA tests. Co‑immunoprecipitation (Co-IP), WB, GST-pulldown, phosphorylation mass spectrometry, surface plasmon resonance (SPR), and IKK activity detection assay were employed to investigate the underlying molecular mechanism by which RMP restrains IKK-NF-κB pathway. Results We identified RNA polymerase II subunit 5 (RPB5)-mediating protein (RMP) as an inhibitor of the IKK complex, which thus inhibited NF-κB signaling in macrophages. In resting macrophages, RMP was directly bound to the kinase domain of IKKβ and inhibited its activity by recruiting protein phosphatase 2 A (PP2A) to the IKK complex. When mouse macrophages were treated with LPS, a Toll-like receptor 4 (TLR4) agonist that stimulates NF-κB signaling, RMP was phosphorylated by IKKβ at Ser439 and dissociated from the IKK complex, which further activated NF-κB signaling. Macrophage-specific deletion of Rmp reduced survival in mice due to an increased inflammatory response in experimental models of sepsis. Conclusions RMP inhibits TLR4-induced NF-κB activation and exerts homeostatic control of innate immunity, and may be promising as a therapeutic target in the limiting of NF-κB signaling and attenuating sepsis-related damage.https://doi.org/10.1186/s12964-025-02278-wIκB kinase β (IKKβ)RNA polymerase II subunit 5-mediating protein (RMP)NF-κBSepsisMacrophageProtein phosphatase 2A (PP2A) |
| spellingShingle | Shu-jie Pang Tian-yi Jiang Nai-guo Wang Xiao-wen Cui Hui Wang Yu-fei Pan Ning Yang Li-wei Dong RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis Cell Communication and Signaling IκB kinase β (IKKβ) RNA polymerase II subunit 5-mediating protein (RMP) NF-κB Sepsis Macrophage Protein phosphatase 2A (PP2A) |
| title | RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis |
| title_full | RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis |
| title_fullStr | RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis |
| title_full_unstemmed | RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis |
| title_short | RNA polymerase II subunit 5-mediating protein limits TLR4-induced innate immune activation in macrophages by inhibiting IKKβ/NF-κB signaling during sepsis |
| title_sort | rna polymerase ii subunit 5 mediating protein limits tlr4 induced innate immune activation in macrophages by inhibiting ikkβ nf κb signaling during sepsis |
| topic | IκB kinase β (IKKβ) RNA polymerase II subunit 5-mediating protein (RMP) NF-κB Sepsis Macrophage Protein phosphatase 2A (PP2A) |
| url | https://doi.org/10.1186/s12964-025-02278-w |
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