Suchergebnisse

The mammalian circadian clock, expressed throughout the brain and body, controls daily metabolic homeostasis. Clock function in peripheral tissues is required, but not sufficient, for this task. Because of the lack of specialized animal models, it is unclear how tissue clocks interact with extrinsic signals to drive molecular oscillations. Here, we isolated the interaction between feeding and the liver clock by reconstituting Bmal1 exclusively in hepatocytes (Liver-RE), in otherwise clock-less mice, and controlling timing of food intake. We found that the cooperative action of BMAL1 and the transcription factor CEBPB regulates daily liver metabolic transcriptional programs. Functionally, the liver clock and feeding rhythm are sufficient to drive temporal carbohydrate homeostasis. By contrast, liver rhythms tied to redox and lipid metabolism required communication with the skeletal muscle clock, demonstrating peripheral clock cross-talk. Our results highlight how the inner workings of the clock system rely on communicating signals to maintain daily metabolism. ; C.M.G. was supported by the National Cancer Institute of the National Institutes of Health (NIH) under award number T32CA009054 and by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement 749869. K.B.K. was supported by NIH-NINDS F32DK121425, and J.G.S. was supported by the Zymo-CEM Postdoctoral Fellowship (Zymo Research). P.P. was supported by a scholarship from the Wenner-Gren Foundations. C.V. and M.M.S. are supported by NIH grants DK20AU4084 and HL138193.The work of S.C., M.S., and P.B. was in part supported by NIH grant GM123558 to P.B. Work in the W.L. laboratory was supported by NIH grants R01HG007538, R01CA193466, and R01CA228140. Work in the P.S.-C. laboratory is supported by NIH grants R21DK114652 and R21AG053592, a Challenge Grant from the Novo Nordisk Foundation (NNF-202585), and through access to the Genomics High Throughput Facility Shared Resource of the Cancer Center Support Grant (CA-62203) at the UCI and NIH-shared instrumentation grants 1S10RR025496-01, 1S10OD010794-01, and 1S10OD021718-01. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. P.-S.W. is supported by a "Ramon y Cajal" contract (RYC2019-026661-I) from the Spanish Ministry of Science and Innovation (MICINN). Research in the P.M.-C. laboratory is supported by MINECO-Spain (RTI2018-096068), ERC-2016-AdG-741966, AFM, MDA-USA, La Marató/TV3 Foundation, LaCaixa-HEALTH-HR17-00040, and UPGRADE-H2020-825825 and María-de-Maeztu-Program for Units of Excellence to UPF (MDM-2014-0370) and Severo-Ochoa-Program for Centers of Excellence to CNIC (SEV-2015-0505). Research in the S.A.B. laboratory is supported by the European Research Council (ERC), the Government of Cataluña (SGR grant), the Government of Spain (MINECO), the La Marató/TV3 Foundation, and The Worldwide Cancer Research Foundation (WCRF). Author contributions: C.M.G., K.B.K., J.G.S., P.B., S.M., S.A.B., P.M.-C., and P.S.-C. conceived and designed the study. C.M.G., K.B.K., J.G.S., S.A.B., P.M.-C., and P.S.-C. wrote and edited the manuscript. C.M.G., K.B.K., J.G.S., P.-S.W., V.M.Z., T.M., K.S., T.S., P.P., S.K.C., and K.A.D. performed experiments. O.D., A.K. and M.V.-D. provided technical support. D.L., J.M.M.K., C.V., and M.M.S. performed bioinformatic correlation analyses. S.C., M.S., P.K., R.C., J.S., and W.L. performed sequencing analysis.

Repair of damaged tissue requires the coordinated action of inflammatory and tissue-specific cells to restore homeostasis, but the underlying regulatory mechanisms are poorly understood. In this paper, we report new roles for MKP-1 (mitogen-activated protein kinase [MAPK] phosphatase-1) in controlling macrophage phenotypic transitions necessary for appropriate muscle stem cell-dependent tissue repair. By restricting p38 MAPK activation, MKP-1 allows the early pro- to antiinflammatory macrophage transition and the later progression into a macrophage exhaustion-like state characterized by cytokine silencing, thereby permitting resolution of inflammation as tissue fully recovers. p38 hyperactivation in macrophages lacking MKP-1 induced the expression of microRNA-21 (miR-21), which in turn reduced PTEN (phosphatase and tensin homologue) levels, thereby extending AKT activation. In the absence of MKP-1, p38-induced AKT activity anticipated the acquisition of the antiinflammatory gene program and final cytokine silencing in macrophages, resulting in impaired tissue healing. Such defects were reversed by temporally controlled p38 inhibition. Conversely, miR-21-AKT interference altered homeostasis during tissue repair. This novel regulatory mechanism involving the appropriate balance of p38, MKP-1, miR-21, and AKT activities may have implications in chronic inflammatory degenerative diseases. ; The authors acknowledge funding from The Ministry of Science and Innovation (PLE2009-0124, SAF2009-09782, FIS-PS09/01267, and SAF2010-21682), Association Française contre les Myopathies, Fundación Marató-TV3/R-Pascual, Muscular Dystrophy Association, and European Union Seventh Framework Programme (Myoage, Optistem, and Endostem). P. Sousa-Victor was supported by a predoctoral fellowship from Fundação para a Ciência e a Tecnologia

Genetic data indicate that abrogation of Notch-Rbpj or Wnt-β-catenin pathways results in the loss of the intestinal stem cells (ISCs). However, whether the effect of Notch is direct or due to the aberrant differentiation of the transit-amplifying cells into post-mitotic goblet cells is unknown. To address this issue, we have generated composite tamoxifen-inducible intestine-specific genetic mouse models and analyzed the expression of intestinal differentiation markers. Importantly, we found that activation of β-catenin partially rescues the differentiation phenotype of Rbpj deletion mutants, but not the loss of the ISC compartment. Moreover, we identified Bmi1, which is expressed in the ISC and progenitor compartments, as a gene that is co-regulated by Notch and β-catenin. Loss of Bmi1 resulted in reduced proliferation in the ISC compartment accompanied by p16(INK4a) and p19(ARF) (splice variants of Cdkn2a) accumulation, and increased differentiation to the post-mitotic goblet cell lineage that partially mimics Notch loss-of-function defects. Finally, we provide evidence that Bmi1 contributes to ISC self-renewal. ; This work has been supported by the Instituto de Salud Carlos III [PI10/01128], Ministerio de Ciencia e Innovación [ACI2009-0918], Agència de Gestió d'Ajuts Universitaris i de Recerca-Convocatòria Estratègica-2010-0006 and Red Temática de Investigación Cooperativa en Cáncer [RD06/0020/0098, RD12/0036/0054]. The Mar Institute of Medical Research (IMIM) Foundation financed V.R., and she is a recipient of a European Molecular Biology Organization (EMBO) short-term fellowship [ASTF 20-2010]. E.L.-A. is funded by 'Fundación la Caixa' (2010) and the Department of Education, Universities and Research of the Basque Government [BFI-2011]. L.L.E. is an investigator of the Spanish National Health System (SNS) [CES08/006]