Biology subjects

Jeong, M.

Publications and source records attributed to Jeong, M..

3 recordsLinked to original sources

bioRxiv2022

Liver sinusoidal endothelial cells orchestrate NK cell recruitment and activation in acute inflammatory liver injury

In both steady-state and during endotoxicosis, liver sinusoidal endothelial cells (LSECs) can rapidly clear lipopolysaccharide (LPS) from the bloodstream. They are located along blood sinusoids of the liver, and establish intimate contact with circulating and tissue-resident immune cells. However, their role in regulating immune responses during LPS-induced endotoxicosis remains poorly understood. Here, we show that LSECs play a dual role in regulating inflammatory responses, acting as modulators of NK cell pro-inflammatory output and as major producers of immune cell-attracting chemokines. We demonstrate that LSECs switch their chemokine expression pattern driven by LPS and IFN-{gamma}, resulting in the production of the myeloid-attracting chemokine CCL2 and the lymphoid-attracting chemokine CXCL10, which accumulate in the serum of LPS-challenged animals. In livers of LPS-injected mice, monocytes and Kupffer cells expressed highest amounts of the pro-inflammatory cytokine Il12a and Il18 transcripts, while NK cells expressed the highest amounts of Ifng. NK cell exposure to LSECs in vitro led to global transcriptomic changes, and primed NK cells to produce higher amounts of IFN-{gamma} in response to IL-12 and IL-18. LSECs required exposure to IFN-{gamma} for Cxcl10 expression, and Cxcl10 gene-deletion in endothelial cells abrogated NK cell accumulation in the liver after LPS treatment. Thus, our data indicate that LSECs occupy a unique temporal and spatial position acting as central regulators that respond to both LPS and immune-derived inflammatory signals, and fuel a positive feedback loop of immune cell attraction and activation in the inflamed liver tissue. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/500206v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@653c53org.highwire.dtl.DTLVardef@5ba4bdorg.highwire.dtl.DTLVardef@9caad8org.highwire.dtl.DTLVardef@1945eb5_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Exercise reprograms the inflammatory landscape of multiple stem cell compartments during mammalian aging

Exercise has the ability to rejuvenate stem cells and improve tissue homeostasis and regeneration in aging animals. However, the cellular and molecular changes elicited by exercise have not been systematically studied across a broad range of cell types in stem cell compartments. To gain better insight into the mechanisms by which exercise affects niche and stem cell function, we subjected young and old mice to aerobic exercise and generated a single cell transcriptomic atlas of muscle, neural and hematopoietic stem cells with their niche cells and progeny. Complementarily, we also performed whole transcriptome analysis of single myofibers from these animals. We identified common and unique pathways that are compromised across these tissues and cell types in aged animals. We found that exercise has a rejuvenating effect on subsets of stem cells, and a profound impact in the composition and transcriptomic landscape of both circulating and tissue resident immune cells. Exercise ameliorated the upregulation of a number of inflammatory pathways as well as restored aspects of cell-cell communication within these stem cell compartments. Our study provides a comprehensive view of the coordinated responses of multiple aged stem cells and niche cells to exercise at the transcriptomic level.

cell biology↗

bioRxiv2021

Effects of Platycodon grandiflorum on Gut Microbiota and Immune System of Immunosuppressed Mouse

Platycodon grandiflorum (PG) has been used as a traditional remedy to control immune related diseases. However, there is limited information about its immune stimulating effects on the immunosuppressed model. The main bioactive components such as saponins are known to con-tribute to controlling immune activity. Thus, we developed an aged red PG (PGS) with 2.6 times of platycodin D, one of the saponins. We treated PG and PGS (PG-diets) to immunosuppressed mice via cyclophosphamide (CPA) injection. After 2weeks of the supplement, 16S rRNA sequencing was performed to investigate the effects of PG-diets on the gut microbiota and immune system in the immune suppressed model. PG-diets groups showed an increased abundance of microorganism in immune-deficient mice compared to the control NC group, indicating PG-diets have a distinct effect on microbial communities. Detection of specific genera related to the immune related biomarkers in PG-diets groups can support their effects on the immune system. Especially, the Akkermansia showed a significant decrease of abundance in response to the CPA treatment in the NC group at the genus level, but its abundance increased in response to the PG-diets treatment in the PG-diets groups. We also found that the modulation of gut microbiome by PG-diets was correlated with body weight as one of important immune biomarkers, though not much difference was found between PG and PGS effects. The results demonstrate that PG-diets may improve the health benefits of immune suppressed mice by altering the gut microbiome.

microbiology↗