Publications by authors named "Young Yon Kwon"

Article Synopsis
  • - The study investigates how caloric restriction (CR) influences the lifespan of yeast mutants with single gene deletions linked to key metabolic pathways like glycolysis, the TCA cycle, and the glyoxylate cycle.
  • - Results show that CR lengthens the chronological lifespan mainly in mutants tied to glycolysis and the TCA cycle, while no lifespan benefit is observed in mutants lacking essential enzymes for the glyoxylate cycle.
  • - Notably, CR boosts the activity of isocitrate lyase, an enzyme in the glyoxylate cycle, but rapamycin (a known lifespan-extending compound) does not enhance this enzyme's activity, indicating that CR operates through a unique metabolic pathway.
View Article and Find Full Text PDF

Various cytokines have been implicated in cancer cachexia. One such cytokine is IL-6, deemed as a key cachectic factor in mice inoculated with colon carcinoma 26 (C26) cells, a widely used cancer cachexia model. Here we tested the causal role of IL-6 in cancer cachexia by knocking out the IL-6 gene in C26 cells.

View Article and Find Full Text PDF

The bacterial determinants that facilitate Mycobacterium tuberculosis (Mtb) adaptation to the human host environment are poorly characterized. We have sought to decipher the pressures facing the bacterium in vivo by assessing Mtb genes that are under positive selection in clinical isolates. One of the strongest targets of selection in the Mtb genome is lldD2, which encodes a quinone-dependent L-lactate dehydrogenase (LldD2) that catalyzes the oxidation of lactate to pyruvate.

View Article and Find Full Text PDF

Unlabelled: Mammalian tissues feed on nutrients in the blood circulation. At the organism-level, mammalian energy metabolism comprises of oxidation, storage, interconverting, and releasing of circulating nutrients. Though much is known about the individual processes and nutrients, a holistic and quantitative model describing these processes for all major circulating nutrients is lacking.

View Article and Find Full Text PDF

The role of glutathione peroxidase 4 (GPX4) in ferroptosis and various cancers is well-established; however, its specific contribution to colorectal cancer has been unclear. Surprisingly, in a genetic mouse model of colon tumors, the deletion of GPX4 specifically in colon epithelial cells increased tumor burden but decreased oxidized glutathione. Notably, this specific GPX4 deletion did not enhance susceptibility to dextran sodium sulfate (DSS)-induced colitis in mice with varied iron diets but showed vulnerability in mice with a vitamin E-deficient diet.

View Article and Find Full Text PDF

The bacterial determinants that facilitate (Mtb) adaptation to the human host environment are poorly characterized. We have sought to decipher the pressures facing the bacterium by assessing Mtb genes that are under positive selection in clinical isolates. One of the strongest targets of selection in the Mtb genome is , which encodes a quinone-dependent L-lactate dehydrogenase (LldD2) that catalyzes the oxidation of lactate to pyruvate.

View Article and Find Full Text PDF

Various cytokines have been implicated in cancer cachexia. One such cytokine is IL-6, which has been deemed a key cachectic factor in mice inoculated with the colon carcinoma 26 (C26) cells, one of the most widely used models of cancer cachexia. Here to test the causal role of IL-6 in cancer cachexia, we used CRISPR/Cas9 editing to knock out in C26 cells.

View Article and Find Full Text PDF
Article Synopsis
  • The study aimed to create a model to predict the age of dogs by analyzing CD4+ and CD8+ cells and certain humoral components in their blood.
  • The research involved 27 dogs of two breeds (Belgian Malinois and German Shepherd) aged 1 to 12 years, measuring various myokines and the ratio of T-lymphocytes.
  • Results showed a significant correlation between the T-lymphocyte ratio and age, with a quadratic mixed model providing better age prediction using the CD4+/CD8+ ratio and GDF8 levels.
View Article and Find Full Text PDF

Senescent cells exhibit a reduced response to intrinsic and extrinsic stimuli. This diminished reaction may be explained by the disrupted transmission of nuclear signals. However, this hypothesis requires more evidence before it can be accepted as a mechanism of cellular senescence.

View Article and Find Full Text PDF

Budding yeast generate heterogeneous cells that can be separated into two distinctive cell types: short-living low-density and long-living high-density (HD) cells by density gradient centrifugation. We found that ethanol and acetate induce formation of HD cells, and mitochondrial respiration is required. From their transcriptomes and metabolomes, we found upregulated differentially expressed genes in HD cells involved in the RGT2/RGT1 glucose sensing pathway and its downstream genes encoding hexose transporters.

View Article and Find Full Text PDF

Caloric restriction (CR) has been shown to extend lifespan and prevent cellular senescence in various species ranging from yeast to humans. Many effects of CR may contribute to extend lifespan. Specifically, CR prevents oxidative damage from reactive oxygen species (ROS) by enhancing mitochondrial function.

View Article and Find Full Text PDF
Article Synopsis
  • Mitochondria are essential for energy production in eukaryotic cells through the electron transport chain (ETC), but they also produce harmful reactive oxygen species (ROS) that contribute to aging by damaging cellular components.
  • A study on 33 yeast strains with deleted ETC components revealed that 14 of the strains exhibited significantly shorter lifespans, associated with specific mutations affecting the ETC complexes and ATP synthase stability.
  • These short-lived strains were found to have increased levels of superoxide and reduced ATP production, indicating that mutations in the ETC lead to decreased mitochondrial efficiency and accelerated aging.
View Article and Find Full Text PDF

Down-regulation of intracellular nutrient signal pathways was proposed to be a primary mechanism of caloric restriction (CR)-mediated lifespan extension. However, the link between lifespan and glucose sensors in the plasma membrane was poorly understood in yeast. Herein, a mutant that lacked glucose sensors (snf3Δrgt2Δ) had impaired glucose fermentation, showed decreased chronological lifespan (CLS), and reduced CLS extension by CR.

View Article and Find Full Text PDF

Caloric restriction mimetics (CRMs) have been developed to mimic the effects of caloric restriction (CR). However, research reports for the effects of CRMs are often times inconsistent across different research groups. Therefore, in this study, we compared seven identified CRMs which extend the lifespans of various organisms including caffeine, curcumin, dapsone, metformin, rapamycin, resveratrol, and spermidine to CR for mitochondrial function in a single model, Saccharomyces cerevisiae.

View Article and Find Full Text PDF
Article Synopsis
  • * Researchers identified critical time periods where CR positively impacts cellular longevity by switching glucose-based media to water, and they analyzed gene expression changes connected to CR's lifespan effects.
  • * They discovered several genes, including AZF1 and XBP1, that play crucial roles in regulating the benefits of CR, with deletions of these genes reducing the lifespan extension associated with CR in specific genetic backgrounds.
View Article and Find Full Text PDF

Activation of Janus kinases (JAKs) and Signal Transducers and Activators of Transcription (STATs) plays a crucial role in cell survival and proliferation. The JAK/STAT signaling pathway has received a great deal of attention as a therapeutic target for the treatment of cancer. Thus, the identification of a compound that blocks this pathway would contribute significantly to growth inhibition and apoptosis of tumor cells.

View Article and Find Full Text PDF