Project description:Mechanisms controlling the proliferative activity of neural stem/progenitor cells (NSPCs) play a pivotal role to ensure life-long neurogenesis in the mammalian brain. How metabolic programs are coupled with NSPC activity remains unknown. Here we show that fatty acid synthase (FASN), the key enzyme of de novo lipogenesis, is highly active in adult NSPCs and that conditional deletion of FASN in NSPCs impairs adult neurogenesis. The rate of de novo lipid synthesis and subsequent proliferation of NSPCs is regulated by Spot14, a gene we found to be selectively expressed in low proliferating adult NSPCs. Spot14 reduces the availability of malonyl-CoA, which is an essential substrate for FASN to fuel lipogenesis. Thus, we here identified a functional coupling between the regulation of lipid metabolism and adult NSPC proliferation. 6 samples were analyzed. Spot14+: Spot14 GFP positive mouse neural stem cell, 3 biological rep Spot14-: Spot14 GFP negative mouse neural stem cell, 3 biological rep
Project description:Mechanisms controlling the proliferative activity of neural stem/progenitor cells (NSPCs) play a pivotal role to ensure life-long neurogenesis in the mammalian brain. How metabolic programs are coupled with NSPC activity remains unknown. Here we show that fatty acid synthase (FASN), the key enzyme of de novo lipogenesis, is highly active in adult NSPCs and that conditional deletion of FASN in NSPCs impairs adult neurogenesis. The rate of de novo lipid synthesis and subsequent proliferation of NSPCs is regulated by Spot14, a gene we found to be selectively expressed in low proliferating adult NSPCs. Spot14 reduces the availability of malonyl-CoA, which is an essential substrate for FASN to fuel lipogenesis. Thus, we here identified a functional coupling between the regulation of lipid metabolism and adult NSPC proliferation.
Project description:Fate and behaviour of neural progenitor cells is tightly regulated during mammalian brain development. Metabolic pathways, such as glycolysis and oxidative phosphorylation, that are required for supplying energy and providing molecular building blocks to generate cells, govern progenitor function. However, the role of de novo lipogenesis, which is the conversion of glucose into fatty acids through the multi-enzyme protein fatty acid synthase (FASN), for brain development remains unknown. Using Emx1Cre-mediated, tissue-specific deletion of Fasn in the mouse embryonic telencephalon, we show that loss of FASN causes severe microcephaly, largely due to altered polarity of apical, radial glia progenitors (APs) and reduced progenitor proliferation. Further, genetic deletion and pharmacological inhibition of FASN in human embryonic stem cell (ESC)-derived forebrain organoids identifies a conserved role of FASN-dependent lipogenesis for radial glia cell polarity and progenitor expansion in the developing human forebrain. Thus, our data establish a role of de novo lipogenesis for mouse and human brain development and identify a link between progenitor cell polarity and lipid metabolism.
Project description:Metabolic diseases are closely linked to aberrant synthesis of endogenous fatty acids in the liver, called de novo lipogenesis (DNL), which is mediated by the enzyme fatty acid synthase (FASN). The composition of complex lipids consists of saturated or monosaturated fatty acids, which can be endogenously produced, and polyunsaturated fatty acids (PUFA), which are strictly dietary. Compositional differences between individuals are insufficiently understood and may influence the onset and progression of metabolic and cardiovascular diseases. Here we show that DNL critically determines the use of dietary PUFA. A patient with a hypofunctional heterozygous de novo Arg2177Cys variant in FASN exhibited an elevated composition of PUFA, which was phenocopied by pharmacological inhibition of FASN with TVB-2640 in patients with nonalcoholic steatohepatitis (NASH). In mice, the incorporation rate of supplemented omega-3 PUFA during an obesogenic diet was increased by genetic or pharmacologic reduction of DNL. Mechanistically, we show that the FASN variant exhibited a cysteine-dependent, non-enzymatic acetylation of FASN, which resulted in hyperubiquitinylation and decreased protein stability. Our study further reveals that PUFA storage is an active, enzymatic process controlled by FASN, diacylglycerol O-acyltransferase 2 (DGAT2) and MFSD2A, a membrane-transport protein, and that combining FASN inhibition and PUFA supplementation exerts additive beneficial metabolic effects. These findings provide evidence that the success of PUFA supplementation may depend on the rate of endogenous DNL and that combined PUFA supplementation and FASN inhibition may be a promising approach targeting metabolic disease.
Project description:Failure of neural stem/progenitor cell (NSPC) activity and subsequently neurogenesis during brain development has been linked to cognitive impairment and intellectual disability. However, it remains unclear if changes in metabolism, recently discovered as a key regulator of somatic stem cell activity, contribute to altered neurogenesis and cognitive deficits in humans. To investigate a link between NSPC-associated lipid metabolism and brain development, we generated mice and human embryonic stem cells (hESCs) mimicking a variant in fatty acid synthase (FASN; R1819W), a metabolic regulator of rodent NSPC activity recently identified in humans with intellectual disability. Mice homozygous for the FASN R1812W variant have impaired hippocampal NSPC activity associated with cognitive impairment due to presumed toxic accumulation of lipids in NSPCs and subsequent lipogenic ER stress. Human NSPCs homozygous for the FASN R1819W variant show reduced rates of proliferation in embryonic 2D cultures and 3D forebrain regionalized organoids, revealing that the functional significance of lipid metabolism for neurogenic proliferation of progenitors is conserved between rodents and humans. By taking a disease modeling approach, using mouse and human tissue genome engineering, our data provide genetic evidence for a link between altered lipid metabolism, NSPC activity and brain function.
Project description:Within the adult mammalian dentate gyrus (DG) of the hippocampus, glutamate stimulates neural stem cell (NSC) self-renewing proliferation, providing a link between adult neurogenesis and local circuit activity. Here, we show that glutamate-induced self-renewal of adult DG NSCs requires glutamate transport via excitatory amino acid transporter 1 (EAAT1) to stimulate lipogenesis. Loss of EAAT1 prevented glutamate-induced self-renewing proliferation of NSCs in vitro and in vivo, with little role evident for canonical glutamate receptors. Transcriptomics and further pathway manipulation revealed that glutamate simulation of NSCs relied on EAAT1 transport-stimulated lipogenesis, likely secondary to intracellular Ca2+ release and glutamate metabolism. Our findings demonstrate a critical, direct role for EAAT1 in stimulating NSCs to support neurogenesis in adulthood, thereby providing insights into a non-canonical mechanism by which NSCs sense and respond their niche.