Hunger-promoting AgRP neurons trigger an astrocyte-mediated feed-forward autoactivation loop in mice.
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ABSTRACT:
SUBMITTER: Varela L
PROVIDER: S-EPMC8121506 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Agouti-related peptide (AGRP)-expressing neurons are activated by fasting-this causes hunger1-4, an aversive state that motivates the seeking and consumption of food5,6. Eating returns AGRP neuron activity towards baseline on three distinct timescales: rapidly and transiently following sensory detection of food cues6-8, slowly and longer-lasting in response to nutrients in the gut9,10, and even more slowly and permanently with restoration of energy balance9,11. The rapid regulation by food cues is of particular interest as its neurobiological basis and purpose are unknown. Given that AGRP neuron activity is aversive6, the sensory cue-linked reductions in activity could function to guide behaviour. To evaluate this, we first identified the circuit mediating sensory cue inhibition and then selectively perturbed it to determine function. Here, we show that a lateral hypothalamic glutamatergic → dorsomedial hypothalamic GABAergic (γ-aminobutyric acid-producing)12 → AGRP neuron circuit mediates this regulation. Interference with this circuit impairs food cue inhibition of AGRP neurons and, notably, greatly impairs learning of a sensory cue-initiated food-acquisition task. This is specific for food, as learning of an identical water-acquisition task is unaffected. We propose that decreases in aversive AGRP neuron activity6 mediated by this food-specific circuit increases the incentive salience13 of food cues, and thus facilitates the learning of food-acquisition tasks.
| S-EPMC8522184 | biostudies-literature
Project description:AgRP neurons drive hunger, and excessive nutrient intake is the primary driver of obesity and associated metabolic disorders. While many factors impacting central regulation of feeding behavior have been established, the role of microRNAs in this process is poorly understood. Utilizing unique mouse models, we demonstrate that miR-33 plays a critical role in the regulation of AgRP neurons, and that loss of miR-33 leads to increased feeding, obesity, and metabolic dysfunction in mice. These effects include the regulation of multiple miR-33 target genes involved in mitochondrial biogenesis and fatty acid metabolism. Our findings elucidate a key regulatory pathway regulated by a non-coding RNA that impacts hunger by controlling multiple bioenergetic processes associated with the activation of AgRP neurons, providing alternative therapeutic approaches to modulate feeding behavior and associated metabolic diseases.
| S-EPMC10923783 | biostudies-literature
Project description:Analysis of miRNA expression in human breast cancer samples with Agilent's miRNA arrays. These samples are part of a study where we have investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. We observed that indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Abstract of paper: Normal cell growth is governed by a complicated biological system, featuring multiple levels of control, often deregulated in cancers. The role of microRNAs in the control of gene expression is now increasingly appreciated, yet their involvement in controlling cell proliferation is still not well understood. Here we investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. Indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Furthermore, we show that these microRNAs silence anti-proliferative genes, which themselves are E2F1 targets. Thus, microRNAs and transcriptional regulators appear to cooperate in the framework of a multi-gene transcriptional and post-transcriptional feed-forward loop. Finally, we show that, similarly to p53 inactivation, overexpression of representative microRNAs promotes proliferation and delays senescence, manifesting the detrimental phenotypic consequence of perturbations in this circuit. Together these findings position microRNAs as novel key players in the mammalian cellular proliferation network. Keywords: Breast Cancer, miRNA, p53. 18 Primary human breast cancer samples analyzed for their miRNA expression. From two to four replicates were performed for each sample. Quality check (QC) were performed with Feature Extraction 9.1.3.44 and arrays not passing QC were excluded
| S-ECPF-GEOD-12848 | biostudies-other
Project description:miRNA expression profiles of WI38 primary human fibroblasts with an active or inactive p53. Cells were compared under normal untreated conditions (young and proliferating cells), after DNA damage with Doxorubicin, and upon entry into replicative senescence. Keywords: miRNA, WI-38, p53, GSE56, Senescence, Doxorubicin, Cancer, DNA-damage, fibroblasts. 6 samples of WI38 cells were analyzed on 12 Exiqon miRcurry LNA arrays in biological duplicates (2 different cell culture plates for each experimental condition). The six conditions included: 1. [Con_Young] - Primary Young WI38 cells (passage 20) with a control retroviral vector (pLXSN-NEO). Untreated. 2. [GSE_Young] -Primary Young WI38 cells (passage 20) with a retroviral vector encoding for the p53-inactivating peptide GSE56 (pLXSN-NEO-GSE56).Untreated. 3. [Con_Dox] -Primary Young WI38 cells (passage 20) with a control retroviral vector (pLXSN-NEO). Treated with Doxorubicin (0.2 micrograms/ml) for 24 hours). 4. [GSE_Dox] Primary Young WI38 cells (passage 20) with a retroviral vector encoding for the p53-inactivating peptide GSE56 (pLXSN-NEO-GSE56). Treated with Doxorubicin (0.2 micrograms/ml) for 24 hours). 5. [Con_Old] - Sesescent WI38 cells (passage 30) with a control retroviral vector (pLXSN-NEO). Untreated. 6. [GSE_Old] - Senescent WI38 cells (passage 26) with a retroviral vector encoding for the p53-inactivating peptide GSE56 (pLXSN-NEO-GSE56).Untreated. RNA was extracted with TRI-Reagent and sent for labeling and hybridization in Exiqon laboratories (In Denamark). Samples were labeled with Cy5. Reference sample (Cy3) was an RNA mix of all samples. Log2 for Ratio(Cy5/Cy3) was used for further analysis.
2010-05-19 | E-GEOD-12450 | biostudies-arrayexpress
Project description:There is a distinctive miRNA expression profile between early (young) and replicative senescence (old). We observed a cluster of miRNAs that were repressed upon senescence in both MRC-5 and WI-38 fibroblast cells. miRNAs profiling in young and senescence human emryonic fibroblasts (MRC-5 and WI-38)
2010-05-19 | E-GEOD-12821 | biostudies-arrayexpress
Project description:Analysis of miRNA expression in human breast cancer samples with Agilent's miRNA arrays. These samples are part of a study where we have investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. We observed that indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Abstract of paper: Normal cell growth is governed by a complicated biological system, featuring multiple levels of control, often deregulated in cancers. The role of microRNAs in the control of gene expression is now increasingly appreciated, yet their involvement in controlling cell proliferation is still not well understood. Here we investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. Indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Furthermore, we show that these microRNAs silence anti-proliferative genes, which themselves are E2F1 targets. Thus, microRNAs and transcriptional regulators appear to cooperate in the framework of a multi-gene transcriptional and post-transcriptional feed-forward loop. Finally, we show that, similarly to p53 inactivation, overexpression of representative microRNAs promotes proliferation and delays senescence, manifesting the detrimental phenotypic consequence of perturbations in this circuit. Together these findings position microRNAs as novel key players in the mammalian cellular proliferation network. Keywords: Breast Cancer, miRNA, p53. 18 Primary human breast cancer samples analyzed for their miRNA expression. From two to four replicates were performed for each sample. Quality check (QC) were performed with Feature Extraction 9.1.3.44 and arrays not passing QC were excluded
2008-09-22 | E-GEOD-12848 | biostudies-arrayexpress
Project description:Normal cell growth is governed by a complicated biological system, featuring multiple levels of control, often deregulated in cancers. The role of microRNAs (miRNAs) in the control of gene expression is now increasingly appreciated, yet their involvement in controlling cell proliferation is still not well understood. Here we investigated the mammalian cell proliferation control network consisting of transcriptional regulators, E2F and p53, their targets and a family of 15 miRNAs. Indicative of their significance, expression of these miRNAs is downregulated in senescent cells and in breast cancers harboring wild-type p53. These miRNAs are repressed by p53 in an E2F1-mediated manner. Furthermore, we show that these miRNAs silence antiproliferative genes, which themselves are E2F1 targets. Thus, miRNAs and transcriptional regulators appear to cooperate in the framework of a multi-gene transcriptional and post-transcriptional feed-forward loop. Finally, we show that, similarly to p53 inactivation, overexpression of representative miRNAs promotes proliferation and delays senescence, manifesting the detrimental phenotypic consequence of perturbations in this circuit. Taken together, these findings position miRNAs as novel key players in the mammalian cellular proliferation network.
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Project description:Cell competition induces the elimination of less-fit "loser" cells by fitter "winner" cells. In Drosophila, cells heterozygous mutant in ribosome genes, Rp/+, known as Minutes, are outcompeted by wild-type cells. Rp/+ cells display proteotoxic stress and the oxidative stress response, which drive the loser status. Minute cell competition also requires the transcription factors Irbp18 and Xrp1, but how these contribute to the loser status is partially understood. Here we provide evidence that initial proteotoxic stress in RpS3/+ cells is Xrp1-independent. However, Xrp1 is sufficient to induce proteotoxic stress in otherwise wild-type cells and is necessary for the high levels of proteotoxic stress found in RpS3/+ cells. Surprisingly, Xrp1 is also induced downstream of proteotoxic stress, and is required for the competitive elimination of cells suffering from proteotoxic stress or overexpressing Nrf2. Our data suggests that a feed-forward loop between Xrp1, proteotoxic stress, and Nrf2 drives Minute cells to become losers.
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Project description:Analysis of miRNA expression in human breast cancer samples with Agilent's miRNA arrays. These samples are part of a study where we have investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. We observed that indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Abstract of paper: Normal cell growth is governed by a complicated biological system, featuring multiple levels of control, often deregulated in cancers. The role of microRNAs in the control of gene expression is now increasingly appreciated, yet their involvement in controlling cell proliferation is still not well understood. Here we investigated the mammalian cell proliferation control network consisting of transcription regulators, E2F and p53, their targets, and a family of 14 microRNAs. Indicative of their significance, expression of these microRNAs is down-regulated in senescent cells and in breast cancers harboring wild-type p53. These microRNAs are repressed by p53 in an E2F1-mediated manner. Furthermore, we show that these microRNAs silence anti-proliferative genes, which themselves are E2F1 targets. Thus, microRNAs and transcriptional regulators appear to cooperate in the framework of a multi-gene transcriptional and post-transcriptional feed-forward loop. Finally, we show that, similarly to p53 inactivation, overexpression of representative microRNAs promotes proliferation and delays senescence, manifesting the detrimental phenotypic consequence of perturbations in this circuit. Together these findings position microRNAs as novel key players in the mammalian cellular proliferation network. Keywords: Breast Cancer, miRNA, p53.
2008-09-23 | GSE12848 | GEO
Project description:There is a distinctive miRNA expression profile between early (young) and replicative senescence (old). We observed a cluster of miRNAs that were repressed upon senescence in both MRC-5 and WI-38 fibroblast cells.
2008-09-25 | GSE12821 | GEO