scholarly journals Clearance of apoptotic neurons without inflammation by microglial triggering receptor expressed on myeloid cells-2

2005 ◽  
Vol 201 (4) ◽  
pp. 647-657 ◽  
Author(s):  
Kazuya Takahashi ◽  
Christian D.P. Rochford ◽  
Harald Neumann

Elimination of apoptotic neurons without inflammation is crucial for brain tissue homeostasis, but the molecular mechanism has not been firmly established. Triggering receptor expressed on myeloid cells-2 (TREM2) is a recently identified innate immune receptor. Here, we show expression of TREM2 in microglia. TREM2 stimulation induced DAP12 phosphorylation, extracellular signal–regulated kinase phosphorylation, and cytoskeleton reorganization and increased phagocytosis. Knockdown of TREM2 in microglia inhibited phagocytosis of apoptotic neurons and increased gene transcription of tumor necrosis factor α and nitric oxide synthase-2, whereas overexpression of TREM2 increased phagocytosis and decreased microglial proinflammatory responses. Thus, TREM2 deficiency results in impaired clearance of apoptotic neurons and inflammation that might be responsible for the brain degeneration observed in patients with polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy/Nasu-Hakola disease.

Circulation ◽  
2002 ◽  
Vol 105 (13) ◽  
pp. 1537-1540 ◽  
Author(s):  
Dinesh K. Kalra ◽  
Xi Zhu ◽  
Mahesh K. Ramchandani ◽  
Gerald Lawrie ◽  
Michael J. Reardon ◽  
...  

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3573
Author(s):  
Lian-Chun Li ◽  
Zheng-Hong Pan ◽  
De-Sheng Ning ◽  
Yu-Xia Fu

Simonsinol is a natural sesqui-neolignan firstly isolated from the bark of Illicium simonsii. In this study, the anti-inflammatory activity of simonsinol was investigated with a lipopolysaccharide (LPS)-stimulated murine macrophages RAW264.7 cells model. The results demonstrated that simonsinol could antagonize the effect of LPS on morphological changes of RAW264.7 cells, and decrease the production of nitric oxide (NO), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) in LPS-stimulated RAW264.7 cells, as determined by Griess assay and enzyme-linked immunosorbent assay (ELISA). Furthermore, simonsinol could downregulate transcription of inducible nitric oxide synthase (iNOS), TNF-α, and IL-6 as measured by reverse transcription polymerase chain reaction (RT-PCR), and inhibit phosphorylation of the alpha inhibitor of NF-κB (IκBα) as assayed by Western blot. In conclusion, these data demonstrate that simonsinol could inhibit inflammation response in LPS-stimulated RAW264.7 cells through the inactivation of the nuclear transcription factor kappa-B (NF-κB) signaling pathway.


Author(s):  
Hanna Galganska ◽  
Wieslawa Jarmuszkiewicz ◽  
Lukasz Galganski

AbstractMitogen-activated protein kinase (MAPK) signalling pathways are crucial for developmental processes, oncogenesis, and inflammation, including the production of proinflammatory cytokines caused by reactive oxygen species and upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are no drugs that can effectively prevent excessive inflammatory responses in endothelial cells in the lungs, heart, brain, and kidneys, which are considered the main causes of severe coronavirus disease 2019 (COVID-19). In this work, we demonstrate that human MAPKs, i.e. extracellular signal-regulated kinases 1 and 2 (ERK1/2), are CO2 sensors and CO2 is an efficient anti-inflammatory compound that exerts its effects through inactivating ERK1/2 in cultured endothelial cells when the CO2 concentration is elevated. CO2 is a potent inhibitor of cellular proinflammatory responses caused by H2O2 or the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. ERK1/2 activated by the combined action of RBD and cytokines crucial for the development of severe COVID-19, i.e. interferon-gamma (IFNγ) and tumour necrosis factor-α (TNFα), are more effectively inactivated by CO2 than by dexamethasone or acetylsalicylic acid in human bronchial epithelial cells. Previously, many preclinical and clinical studies showed that the transient application of 5–8% CO2 is safe and effective in the treatment of many diseases. Therefore, our research indicates that CO2 may be used for the treatment of COVID-19 as well as the modification of hundreds of cellular pathways.


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