Project description:Transcriptionnal profiling of C. perfringens 13 strain comparing growth in minimal medium with 1 mM homocysteine with growth in minimal medium with 0.5 mM cystine.
Project description:Transcriptional profiling of C. perfringens 13 strain compared with strain 13∆cpe1786 erm after growth in minimal medium with 0.5 mM cystine.
Project description:Vascular calcification is a common manifestation of atherosclerosis and involves cell-mediated processes similar to the formation of bone (osteogenesis). Elevated plasma levels of homocysteine are an independent risk factor for atherosclerotic vascular disease but the underlying mechanisms remain unclear. We postulated that hcy can modulate the cells involved in atherosclerosis to promote calcification. Cell experiments were performed to assess the effect of homocysteine on the osteogenic differentiation of aortic smooth muscle cells (AoSMC). Keywords: dose repsonse comparison To study the ability of homocysteine to induce osteogenic differentiation, AoSMC were cultured in T75 flasks (7.5x10E5 /mL) in growth medium with 0, 10 and 100 μmol/L DL-homocysteine. Four biological replicates were prepared for each condition. After 14 days, RNA was extracted from cells and the expression levels of osteogenic genes were compared between the different conditions of homocysteine concentration.
Project description:Altered metabolism is an important part of malignant transformation of tumor cells. Oncogenic transformation may reprogram tumor metabolism and render tumor cells addicted to extracellular nutrients. Such nutrient addictions associated with oncogenic mutations may offer therapeutic opportunities; however, it remains difficult to predict these nutrient addictions. Here, we performed a nutrigenetic screen to determine the phenotypes of isogenic pairs of clear-cell renal cancer cells (ccRCC) with or without VHL upon the deprivation of individual amino acids. We identified that cystine deprivation triggered rapid programmed necrosis in VHL-deficient RCC, but not in their VHL-restored counterparts. Similar cystine addiction was also observed in VHL-deficient primary RCC tumors cells. Blockage of cystine uptake significantly delayed xenograft growth of ccRCC. Importantly, cystine deprivation triggered similar metabolic changes regardless of VHL status. Therefore, metabolic differences due to cystine deprivation are not different enough to readily explain the distinct fate of life vs. death in VHL-deficient and restored cell.. Instead, we found that increased levels of TNFα associated with VHL loss in the VHL-deficient RCC force them to rely on intact RIPK1 to inhibit apoptosis. However, this pre-existing elevated TNFα in the VHL-deficient ccRCC renders these cells susceptible to the necrosis signaling triggered by cystine deprivation. In addition, we identified that cystine-deprived necrosis in VHL-deficient RCC depends on reciprocal amplification of the Src-p38-Noxa signaling and TNFα-RIP1/3-MLKL necrosis pathways that culminate in MLKL oligomerization and programmed necrosis. Together, our data reveal that the contextual cystine-addictions in VHL-deficient ccRCC is dependent on activating pre-existing oncogenic pathways to trigger programmed necrosis. RNA was extracted by RNAeasy kits (Qiagen) from the RCC4 Vec and VHL-reconstituted cells which were exposed to the control full DMEM or cystine deprived DMEM media for 6 hours (three replicates in each condition).
Project description:Transcriptional profiling of C. perfringens 13 strain compared with strain 13?cpe1786 erm after growth in minimal medium with 0.5 mM cystine. two-condition experiment, 13 vs 13?cpe1786 erm, 4 biological replicates for each condition
Project description:The amino acid homocysteine increases in the serum when there is insufficient folic acid or vitamin B12, or with certain mutations in enzymes important in methionine metabolism. Elevated homocysteine is related to increased risk for cardiovascular and other diseases in adults and elevated maternal homocysteine increases the risk for certain congenital defects, especially those that result from abnormal development of the neural crest and neural tube. Experiments with the avian embryo model have shown that elevated homocysteine perturbs neural crest / neural tube migration in vitro and in vivo. While there have been numerous studies of homocysteine-induced changes in gene expression in adult cells, there is no previous report of a homocysteine-responsive transcriptome in the embryonic neural crest. We treated neural crest cells in vitro with exogenous homocysteine in a protocol that induces significant changes in neural crest cell migration. We used microarray analysis and expression profiling to identify 65 transcripts of genes of known function that were altered by homocysteine. The largest set of effected genes (19) included those with a role in cell migration and adhesion. Other major groups were genes involved in metabolism (13); DNA / RNA interaction (11); cell proliferation / apoptosis (10); and transporter / receptor (6). Although the genes identified in this experiment were consistent with prior observations of the effect of homocysteine upon neural crest cell function, none had been identified previously as response to homocysteine in adult cells. Keywords: homocysteine ● microarray ● expression profiling ● embryo ● neural crest
Project description:The amino acid cysteine and its oxidized dimeric form cystine are commonly believed to be synonymous in metabolic functions. Cyst(e)ine depletion not only induces amino acid response, but also triggers ferroptosis, a non-apoptotic cell death. Here we report that, unlike general amino acid starvation, cyst(e)ine deprivation triggers ATF4 induction at the transcriptional level. Unexpectedly, it is the shortage of lysosomal cystine, but not the cytosolic cysteine, that elicits the adaptative ATF4 response. The lysosome-nucleus signaling pathway involves the aryl hydrocarbon receptor (AhR) that senses lysosomal cystine via the kynurenine pathway. A blockade of lysosomal cystine efflux attenuates ATF4 induction and sensitizes ferroptosis. To potentiate ferroptosis in cancer, we develop a synthetic mRNA reagent CysRx that converts cytosolic cysteine to lysosomal cystine. CysRx maximizes cancer cell ferroptosis and effectively suppresses tumor growth in vivo. Thus, intracellular nutrient reprogramming has the potential to induce selective ferroptosis in cancer without systematic perturbation.