20.500.12556/RUL-145265 Cysteine peptidase cathepsin X as a therapeutic target for simultaneous TLR3/4-mediated microglia activation Microglia are resident macrophages in the central nervous system that are involved in immune responses driven by toll-like receptors (TLRs). Microglia-mediated inflammation can lead to central nervous system disorders, and more than one TLR might be involved in these pathological processes. The cysteine peptidase cathepsin X has been recognized as a pathogenic factor for inflammation-induced neurodegeneration. Here, we hypothesized that simultaneous TLR3 and TLR4 activation induces synergized microglia responses and that these phenotype changes affect cathepsin X expression and activity. Murine microglia BV2 cells and primary murine microglia were exposed to the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)) and the TLR4 ligand lipopolysaccharide (LPS), individually and simultaneously. TLR3 and TLR4 co-activation resulted in increased inflammatory responses compared to individual TLR activation, where poly(I:C) and LPS induced distinct patterns of proinflammatory factors together with different patterns of cathepsin X expression and activity. TLR co-activation decreased intracellular cathepsin X activity and increased cathepsin X localization at the plasma membrane with concomitant increased extracellular cathepsin X protein levels and activity. Inhibition of cathepsin X in BV2 cells by AMS36, cathepsin X inhibitor, significantly reduced the poly(I:C)- and LPS-induced production of proinflammatory cytokines as well as apoptosis. Additionally, inhibiting the TLR3 and TLR4 common signaling pathway, PI3K, with LY294002 reduced the inflammatory responses of the poly(I:C)- and LPS-activated microglia and recovered cathepsin X activity. We here provide evidence that microglial cathepsin X strengthens microglia activation and leads to subsequent inflammation-induced neurodegeneration. As such, cathepsin X represents a therapeutic target for treating neurodegenerative diseases related to excess inflammation. microglia toll-like receptors cathepsin X proinfammatory mediators neuroinfammation neuroprotection mikroglija receptorji TLR katepsin X protivnetni mediatorji nevrovnetje nevroprotekcija motnje živčnega sistema imunski odziv true false true Angleški jezik Slovenski jezik Članek v reviji 2023-04-14 11:02:59 2023-04-14 11:03:03 2023-04-15 03:35:48 0000-00-00 00:00:00 2022 0 0 Str. 2258–2276 iss. 4 Vol. 59 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 616-097:616.8 0893-7648 10.1007/s12035-021-02694-2 95406083 s12035-021-02694-2.pdf s12035-021-02694-2.pdf 1 B6A1F14256F78603B69F6FCE1A202178 b0c0eece3333f1be377f81a70bcd4e3526df6ae9bf821d44c37b4e9e85f614c3 4e3e95e5-daa3-11ed-a314-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=168013 https://link.springer.com/article/10.1007/s12035-021-02694-2 0 292f0742-daa3-11ed-a314-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=168012 Fakulteta za farmacijo 0 0 0