ABSTRACT
Successful generation of induced pluripotent stem cells entails a major metabolic switch from mitochondrial oxidative phosphorylation to glycolysis during the reprogramming process. The mechanism of this metabolic reprogramming, however, remains elusive. Here, our results suggest that an Atg5-independent autophagic process mediates mitochondrial clearance, a characteristic event involved in the metabolic switch. We found that blocking such autophagy, but not canonical autophagy, inhibits mitochondrial clearance, in turn, preventing iPSC induction. Furthermore, AMPK seems to be upstream of this autophagic pathway and can be targeted by small molecules to modulate mitochondrial clearance during metabolic reprogramming. Our work not only reveals that the Atg5-independent autophagy is crucial for establishing pluripotency, but it also suggests that iPSC generation and tumorigenesis share a similar metabolic switch.
Subject(s)
Autophagy , Cellular Reprogramming , Induced Pluripotent Stem Cells/metabolism , Microtubule-Associated Proteins/metabolism , Mitochondria/metabolism , AMP-Activated Protein Kinases/metabolism , Aminoimidazole Carboxamide/analogs & derivatives , Aminoimidazole Carboxamide/pharmacology , Animals , Autophagy-Related Protein 5 , Blotting, Western , Cells, Cultured , Embryo, Mammalian/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/ultrastructure , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Induced Pluripotent Stem Cells/drug effects , Mice, Inbred C57BL , Mice, Knockout , Microscopy, Electron , Microscopy, Fluorescence , Microtubule-Associated Proteins/genetics , Octamer Transcription Factor-3/genetics , Octamer Transcription Factor-3/metabolism , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , Ribonucleotides/pharmacology , Sirolimus/pharmacologyABSTRACT
In an effort to expand the stereochemical and structural complexity of chemical libraries used in drug discovery, the Center for Chemical Methodology and Library Development at Boston University has established an infrastructure to translate methodologies accessing diverse chemotypes into arrayed libraries for biological evaluation. In a collaborative effort, the NIH Chemical Genomics Center determined IC(50)'s for Plasmodium falciparum viability for each of 2,070 members of the CMLD-BU compound collection using quantitative high-throughput screening across five parasite lines of distinct geographic origin. Three compound classes displaying either differential or comprehensive antimalarial activity across the lines were identified, and the nascent structure activity relationships (SAR) from this experiment used to initiate optimization of these chemotypes for further development.
Subject(s)
Antimalarials , Malaria, Falciparum/drug therapy , Plasmodium falciparum/growth & development , Antimalarials/chemical synthesis , Antimalarials/chemistry , Antimalarials/pharmacology , Humans , Structure-Activity RelationshipABSTRACT
Chloroazaphilone is a common structure found in a number of natural products. Reported herein is a practical synthesis of a model chloroazaphilone that utilizes Pb(OAc)4 oxidation of HClO4/HOAc pyrinium salt in a key one-pot operation. Reaction of this chloroazaphilone with various primary amines to afford the corresponding vinylogous gamma-pyridones was also fully investigated. The isolation of stable enamine intermediates provided direct evidence of reaction mechanisms.
