Biology subjects

Lee, M.-s.

Publications and source records attributed to Lee, M.-s..

3 recordsLinked to original sources

bioRxiv2023

ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation

We studied lysosomal Ca2+ in inflammasome. LPS+palmitic acid (PA) decreased lysosomal Ca2+ ([Ca2+]Lys) and increased [Ca2+]i through mitochondrial ROS, which was suppressed in Trpm2-KO macrophages. Inflammasome activation and metabolic inflammation in adipose tissue of high-fat diet (HFD)-fed mice were ameliorated by Trpm2 KO. ER[->]lysosome Ca2+ refilling occurred after lysosomal Ca2+ release whose blockade attenuated LPS+PA-induced inflammasome. Subsequently, store-operated Ca2+entry (SOCE) was activated whose inhibition suppressed inflammasome. SOCE was coupled with K+ efflux whose inhibition reduced ER Ca2+ content ([Ca2+]ER) and impaired [Ca2+]Lys recovery. LPS+PA activated KCa3.1 channel, a Ca2+-activated K+ channel. Inhibitors of KCa3.1 channel or Kcnn4 KO reduced [Ca2+]ER, attenuated increase of [Ca2+]i or inflammasome activation by LPS+PA, and ameliorated HFD-induced inflammasome or metabolic inflammation. Lysosomal Ca2+ release induced delayed JNK and ASC phosphorylation through CAMKII-ASK1. These results suggest a novel role of lysosomal Ca2+ release sustained by ER[->]lysosome Ca2+ refilling and K+ efflux through KCa3.1 channel in inflammasome activation and metabolic inflammation.

immunology↗

bioRxiv2021

TET1 controls Cxcl1 induction by DNA demethylation and promotes neutrophil recruitment during acute lung injury

Neutrophils are rapidly recruited from the peripheral blood to the inflammatory site to initiate inflammatory response against pathogenic infections. The process to recruit neutrophils must be properly regulated since the abnormal accumulation of neutrophils can cause organ damage and dysfunction. The acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) is a common cause of respiratory failure that is characterized by the infiltration of neutrophils and epithelial integrity disruption. Indeed, recent studies suggest a pathogenic role of neutrophils in the clinic severity of the coronavirus disease 2019 (COVID-19) ARDS. The chemokine CXCL1, which is rapidly induced by inflammatory stimuli, plays a key role in neutrophil influx during lung inflammation. The molecular basis of Cxcl1 induction is not fully understood. Here we report that TET1, a member of the ten eleven translocation (TET) methylcytosine dioxygenase protein family, displays a striking specificity in the regulation of gene expression in macrophages. RNA sequencing (RNA-seq) analysis showed that Tet1 disruption significantly altered the expression of only 48 genes that include Cxcl1 and several other genes known to be important for cell migration and trafficking in bone marrow derived macrophages (BMDMs) in response to LPS stimulation. TET1 regulates the induction of Cxcl1 by facilitating the DNA demethylation of the Cxcl1 promoter. In Tet1-/- mice, the induction of Cxcl1 was suppressed, resulting in defective neutrophil recruitment to the lung during LPS-induced acute lung injury. Our results identify a novel epigenetic mechanism that selectively controls Cxcl1 induction and neutrophil recruitment during acute lung injury. Key PointsO_LITET1 has a striking specificity in macrophage gene regulation and controls Cxcl1 induction by inflammatory stimuli via DNA demethylation C_LIO_LINeutrophil recruitment is defective in Tet1 deficient mice during acute lung injury C_LI

immunology↗

bioRxiv2021

CRTC2 regulates plasma cell metabolism and survival

Antibody secreting cell (ASC) function and longevity determines the strength and durability of a humoral immune response. Previously, we identified the inactivation of the CREB-regulated transcriptional coactivator-2 (CRTC2) in an in vitro B cell differentiation assay that produced functional ASCs. However, the requirement for CRTC2 inactivation in ASC physiology in vivo remains unknown. Using transgenic (TG) mice that express a constitutively active form of CRTC2 (Crtc2-AA) as an experimental tool, we demonstrate that Crtc2 repression in plasma cells (PCs) is an intrinsic requirement for ASC metabolic fitness. Sustained CRTC2 activity shortens the survival of splenic and bone marrow PCs, resulting in reduced numbers of long-lived PCs and antibody deficits against T cell dependent and independent antigens, and an acute viral infection. TG PCs resemble short-lived PCs with reductions in glycolysis, oxidative metabolism, spare respiratory capacity, and antibody secretion. Mechanistically, Crtc2 repression is necessary for the fidelity of PC gene expression and mRNA alternative-splicing programs. Combined, Crtc2 repression in PCs must occur to support PC metabolism and extend ASC survival during a humoral immune response.

immunology↗