Project description:Cellular senescence impacts many physiological and pathological processes. A durable cell cycle arrest, inflammatory secretory phenotype, and metabolic reprogramming characterize it. Identifying common and specific metabolic liabilities in senescence provide novel inroads to exploit senescence targeting for health benefits. Here, we use dynamic transcriptome and metabolome profiling in different senescence subtypes to reveal common and specific metabolic signatures. Specifically, we pinpoint the homeostatic switch of glycerol-3-phosphate (G3P) and phosphoethanolamine (PEtn) accumulation, intimately linking lipid metabolism to the senescence gene expression program. Mechanistically, p53-dependent glycerol kinase (GK) activation and post-translational inactivation of Phosphate Cytidylyltransferase 2- Ethanolamine (PCYT2) regulate this metabolic switch, which is senogenic. Conversely, G3P phosphatase (G3PP) and Ethanolamine-Phosphate Phospho-Lyase (ETNPPL)-based scavenging of G3P and PEtn is senomorphic. Collectively, our study ties the G3P-PEtn homeostatic switch to controlling lipid droplet biogenesis and phospholipid flux in senescent cells, providing a potential, novel therapeutic avenue for senescence targeting in pathophysiology.
Project description:Cellular senescence impacts many physiological and pathological processes. A durable cell cycle arrest, inflammatory secretory phenotype, and metabolic reprogramming characterize it. Identifying common and specific metabolic liabilities in senescence provide novel inroads to exploit senescence targeting for health benefits. Here, we use dynamic transcriptome and metabolome profiling in different senescence subtypes to reveal common and specific metabolic signatures. Specifically, we pinpoint the homeostatic switch of glycerol-3-phosphate (G3P) and phosphoethanolamine (PEtn) accumulation, intimately linking lipid metabolism to the senescence gene expression program. Mechanistically, p53-dependent glycerol kinase (GK) activation and post-translational inactivation of Phosphate Cytidylyltransferase 2- Ethanolamine (PCYT2) regulate this metabolic switch, which is senogenic. Conversely, G3P phosphatase (G3PP) and Ethanolamine-Phosphate Phospho-Lyase (ETNPPL)-based scavenging of G3P and PEtn is senomorphic. Collectively, our study ties the G3P-PEtn homeostatic switch to controlling lipid droplet biogenesis and phospholipid flux in senescent cells, providing a potential, novel therapeutic avenue for senescence targeting in pathophysiology.
Project description:New chemotherapeutics are urgently required to control the tuberculosis pandemic fueled by the emergence of multidrug- and extensively-drug-resistant Mycobacterium tuberculosis strains and the bacterium`s catastrophic alliance with HIV. Here we describe a novel trehalose-to-α-glucan pathway in M. tuberculosis comprising four enzymatic steps mediated by TreS, Pep2, GlgB, and GlgE, identified as an essential maltosyltransferase capable of utilizing maltose 1-phosphate. Using traditional and chemical reverse genetics, we show that GlgE inactivation causes rapid death of M. tuberculosis in vitro and in mice, through self-poisoning by maltose 1-phosphate accumulation driven by a self-amplifying feedback loop promoting pleiotropic phosphosugar-induced stress responses. Moreover, this α-glucan pathway exhibited a synthetic lethal interaction with the glucosyltransferase Rv3032 involved in biosynthesis of specialized α-glucan derivatives. The unique combination of gene essentiality within a synthetic lethal pathway validates GlgE as a new class of drug targets, revealing novel synergistic mechanisms to induce death in M. tuberculosis. Transcriptional profiling was performed to characterize the lethality induced by maltose 1-phosphate accumulation. Triplicate 10 mL cultures of the conditional lethal Mtb mutant strain H37Rv Delta treS Delta glgE (pMV361::treS) and of the vector control strain H37Rv Delta treS Delta glgE (pMV361) were grown in liquid culture to log-phase in the presence of 5 mM validamycin A (VA) to suppress M1P formation. Subsequently, cells were washed to remove the inhibitor; after 48 h of starvation for VA cultures were harvested. Keywords: tuberculosis, trehalose, compound treatment design, genetic modification design, and stimulus or stress design
Project description:The dystrophin-glycoprotein complex connects the cytoskeleton with base membrane components such as laminin through unique O-glycans displayed on α-dystroglycan (α-DG). Genetic impairment of elongation of these glycans causes congenital muscular dystrophies. We previously identified that glycerol phosphate (GroP) can cap the core part of the α-DG O-glycans and terminate their further elongation. This study examined the possible roles of the GroP modification in cancer malignancy, focusing on colorectal cancer. We found that the GroP modification critically depends on PCYT2, which serves as cytidine 5'-diphosphate-glycerol (CDP-Gro) synthase. Furthermore, we identified a significant positive correlation between cancer progression and GroP modification, which also correlated positively with PCYT2 expression. Moreover, we demonstrate that GroP modification promotes the migration of cancer cells. Based on these findings, we propose that the GroP modification by PCYT2 disrupts the glycan-mediated cell adhesion to the extracellular matrix and thereby enhances cancer metastasis. Thus, the present study suggests the possibility of novel approaches for cancer treatment by targeting the PCYT2-mediated GroP modification.
Project description:The goal of the study is to use Next generation sequencing (RNA-seq) to study the underlying regulation of glycerol metabolism in mixed culture fermentation (glucose and glycerol) of Rhodosporidium toruloides. We sequenced the RNA from 4 different samples in the mixed culture (glucose and glycerol) with 2 replicates each. Transcriptional profiles showed that glycerol might be produced intracellularly and glycerol kinase (GUT1) and glycerol 3–phosphate dehydrogenase (GUT2) enzymes were not down-regulated in the presence of glucose at the transcriptional level. It also showed that this yeast has a different regulation compared to S.cerevisiae. Certain insights into lipid biosynthesis on these mixed cultures are provided at systems level. This analysis provides interesting targets for metabolic engineering in this organism growing on glucose and glycerol.
Project description:The genome of the osmophilic Aspergillus wentii, unlike that of the osmotolerant Aspergillus nidulans, contains only the gfdA but not the gfdB glycerol 3-phosphate dehydrogenase gene. Here, we studied transcriptomic changes of A. nidulans (reference strain and DgfdB gene deletion mutant) and A. wentii (reference strain and An-gfdB expressing mutant) elicited by high osmolarity. A. nidulans showed canonic hyperosmotic stress response characterized by upregulation of trehalose and glycerol metabolism genes (including gfdB) as well as genes of the high-osmolarity glycerol (HOG) map kinase pathway. Deletion of gfdB caused only negligible alterations in the transcriptome suggesting that the glycerol metabolism was flexible enough to compensate for the missing GfdB activity in this species. A. wentii responded differently to increased osmolarity than A. nidulans: E.g.; bulk upregulation of glycerol and trehalose metabolism genes as well as HOG pathway genes were not detected. Expression of An-gfdB in A. wentii did not abolish osmophilia, but it reduced growth and caused much bigger alterations in the transcriptome than the missing gfdB gene did in A. nidulans. Flexible glycerol metabolism and hence two differently regulated gfd genes may be more beneficial for osmotolerant (living under changing osmolarity) than for osmophilic (living under constantly high osmolarity) species.
Project description:5-methylcytosine (m5C) is emerging as an important epi-transcriptome modification involving RNA stability and translation efficiency in various biological processes. However, it remains unclear how m5C contributes to the dynamic regulation of transcriptome during the development of Plasmodium. Here, we identified the presence of 5-methylcytosine (m5C) modification in rodent (P. yoelii) and human (P. falciparum) malaria parasites transcriptome and depicted a comprehensive characterization landscape of m5C mRNA modification at single-nucleotide resolution (RNA-BisSeq) from asexual replicating stage to gametocyte development. Through transcriptome-wide profiling of mRNA m5C modification, we found that m5C modified mRNA displayed higher stability than non-m5C modified mRNA during the development of Plasmodium. We identified Plasmodium ortholog of NSUN2 as an mRNA m5C methyltransferase in malaria parasites. LC–MS/MS and RNA-BisSeq analysis revealed a large decrease in mRNA m5C modification at transcriptome-wide level upon Nsun2 knockout. Absence of Nsun2 severely reduced gametocyte production in either rodent (P. yoelii) or human (P. falciparum) malaria parasites. Meanwhile, some genes related to gametocytogenesis displayed a great reduction of m5C modification. Together, our data provides comprehensive mRNA m5C profiles in Plasmodium genus and reveals m5C modification-mediated mRNA stability as a novel mechanism regulating sexual differentiation of a unicellular eukaryote.
Project description:5-methylcytosine (m5C) is emerging as an important epi-transcriptome modification involving RNA stability and translation efficiency in various biological processes. However, it remains unclear how m5C contributes to the dynamic regulation of transcriptome during the development of Plasmodium. Here, we identified the presence of 5-methylcytosine (m5C) modification in rodent (P. yoelii) and human (P. falciparum) malaria parasites transcriptome and depicted a comprehensive characterization landscape of m5C mRNA modification at single-nucleotide resolution (RNA-BisSeq) from asexual replicating stage to gametocyte development. Through transcriptome-wide profiling of mRNA m5C modification, we found that m5C modified mRNA displayed higher stability than non-m5C modified mRNA during the development of Plasmodium. We identified Plasmodium ortholog of NSUN2 as an mRNA m5C methyltransferase in malaria parasites. LC–MS/MS and RNA-BisSeq analysis revealed a large decrease in mRNA m5C modification at transcriptome-wide level upon Nsun2 knockout. Absence of Nsun2 severely reduced gametocyte production in either rodent (P. yoelii) or human (P. falciparum) malaria parasites. Meanwhile, some genes related to gametocytogenesis displayed a great reduction of m5C modification. Together, our data provides comprehensive mRNA m5C profiles in Plasmodium genus and reveals m5C modification-mediated mRNA stability as a novel mechanism regulating sexual differentiation of a unicellular eukaryote.
Project description:5-methylcytosine (m5C) is emerging as an important epi-transcriptome modification involving RNA stability and translation efficiency in various biological processes. However, it remains unclear how m5C contributes to the dynamic regulation of transcriptome during the development of Plasmodium. Here, we identified the presence of 5-methylcytosine (m5C) modification in rodent (P. yoelii) and human (P. falciparum) malaria parasites transcriptome and depicted a comprehensive characterization landscape of m5C mRNA modification at single-nucleotide resolution (RNA-BisSeq) from asexual replicating stage to gametocyte development. Through transcriptome-wide profiling of mRNA m5C modification, we found that m5C modified mRNA displayed higher stability than non-m5C modified mRNA during the development of Plasmodium. We identified Plasmodium ortholog of NSUN2 as an mRNA m5C methyltransferase in malaria parasites. LC–MS/MS and RNA-BisSeq analysis revealed a large decrease in mRNA m5C modification at transcriptome-wide level upon Nsun2 knockout. Absence of Nsun2 severely reduced gametocyte production in either rodent (P. yoelii) or human (P. falciparum) malaria parasites. Meanwhile, some genes related to gametocytogenesis displayed a great reduction of m5C modification. Together, our data provides comprehensive mRNA m5C profiles in Plasmodium genus and reveals m5C modification-mediated mRNA stability as a novel mechanism regulating sexual differentiation of a unicellular eukaryote.