TY - JOUR
T1 - Janus Kinase Inhibitor Brepocitinib Rescues Myelin Phagocytosis Under Inflammatory Conditions
T2 - In Vitro Evidence from Microglia and Macrophage Cell Lines
AU - Romero-Ramirez, Lorenzo
AU - Garcia-Rama, Concepcion
AU - Mey, Jorg
PY - 2024/2/1
Y1 - 2024/2/1
N2 - Central nervous system (CNS) injuries induce cell death and consequently the release of myelin and other cellular debris. Microglia as well as hematogenous macrophages actively collaborate to phagocyte them and undergo their degradation. However, myelin accumulation persists in the lesion site long after the injury with detrimental effects on axonal regeneration. This might be due to the presence of inhibitors of phagocytosis in the injury site. As we recently published that some proinflammatory stimuli, like interferon-gamma (IFN gamma) and lipopolysaccharide (LPS), inhibit myelin phagocytosis in macrophages, we have now studied the signaling pathways involved. A phagocytosis assay in Raw264.7 macrophages and N13 microglia cell lines with labeled myelin was developed with the pHrodo reagent that emits fluorescence in acidic cellular compartments (e.g.lysosomes). Pharmacological inhibition of Janus kinases (Jak) with Brepocitinib restored myelin phagocytosis and rescued the expression of genes related to phagocytosis, like triggering receptor expressed on myeloid cells 2 (TREM2), induced by IFN gamma or LPS. In addition, while pharmacological inhibition of the signal transducer and activator of transcription 3 (STAT3) rescued myelin phagocytosis and the expression of phagocytosis related genes in the presence of LPS, it did not have any effect on IFN gamma-treated cells. Our results show that Jak pathways participate in the inhibition of myelin phagocytosis by IFN gamma and LPS. They also indicate that the resolution of inflammation is important for the clearance of cellular debris by macrophages and subsequent regenerative processes.
AB - Central nervous system (CNS) injuries induce cell death and consequently the release of myelin and other cellular debris. Microglia as well as hematogenous macrophages actively collaborate to phagocyte them and undergo their degradation. However, myelin accumulation persists in the lesion site long after the injury with detrimental effects on axonal regeneration. This might be due to the presence of inhibitors of phagocytosis in the injury site. As we recently published that some proinflammatory stimuli, like interferon-gamma (IFN gamma) and lipopolysaccharide (LPS), inhibit myelin phagocytosis in macrophages, we have now studied the signaling pathways involved. A phagocytosis assay in Raw264.7 macrophages and N13 microglia cell lines with labeled myelin was developed with the pHrodo reagent that emits fluorescence in acidic cellular compartments (e.g.lysosomes). Pharmacological inhibition of Janus kinases (Jak) with Brepocitinib restored myelin phagocytosis and rescued the expression of genes related to phagocytosis, like triggering receptor expressed on myeloid cells 2 (TREM2), induced by IFN gamma or LPS. In addition, while pharmacological inhibition of the signal transducer and activator of transcription 3 (STAT3) rescued myelin phagocytosis and the expression of phagocytosis related genes in the presence of LPS, it did not have any effect on IFN gamma-treated cells. Our results show that Jak pathways participate in the inhibition of myelin phagocytosis by IFN gamma and LPS. They also indicate that the resolution of inflammation is important for the clearance of cellular debris by macrophages and subsequent regenerative processes.
KW - Brepocitinib
KW - Janus kinases
KW - IFN gamma
KW - LPS
KW - Macrophages
KW - Myelin phagocytosis
KW - TYROSINE PHOSPHORYLATION
KW - APOPTOTIC NEUTROPHILS
KW - ACTIVATION
KW - STAT3
KW - EXPRESSION
U2 - 10.1007/s12035-024-03963-6
DO - 10.1007/s12035-024-03963-6
M3 - Article
SN - 0893-7648
JO - Molecular Neurobiology
JF - Molecular Neurobiology
ER -