Adipogenesis is the formation of adipocytes (fat cells) from stem cells.[1] It involves 2 phases, determination, and terminal differentiation. Determination is mesenchymal stem cells committing to the adipocyte precursor cells, also known as lipoblasts or preadipocytes which lose the potential to differentiate to other types of cells such as chondrocytes, myocytes, and osteoblasts.[2] Terminal differentiation is that preadipocytes differentiate into mature adipocytes. Adipocytes can arise either from preadipocytes resident in adipose tissue, or from bone-marrow derived progenitor cells that migrate to adipose tissue.[3]
Introduction
Adipocytes play a vital role in energy homeostasis and process the largest energy reserve as triglycerol in the body of animals.[4] Adipocytes stay in a dynamic state, they start expanding when the energy intake is higher than the expenditure and undergo mobilization when the energy expenditure exceeds the intake. This process is highly regulated by counter regulatory hormones to which these cells are very sensitive. The hormone insulin promotes expansion whereas the counter hormones epinephrine, glucagon, and ACTH promote mobilization. Adipogenesis is a tightly regulated cellular differentiation process, in which mesenchymal stem cells committing to preadipocytes and preadipocytes differentiating into adipocytes. Cellular differentiation is a change of gene expression patterns which multipotent gene expression alters to cell type specific gene expression. Therefore, transcription factors are crucial for adipogenesis. Transcription factors, peroxis proliferator-activated receptor γ (PPARγ) and CCAAT enhancer-binding proteins (C/EBPs) are main regulators of adipogenesis.[5] Comparing with cells from other lineage, the in vitro differentiation of fat cells is authentic and recapitulates most of the characteristic feature of in vivo differentiation. The key features of differentiated adipocytes are growth arrest, morphological change, high expression of lipogenic genes and production of adipokines like adiponectin, leptin, resistin (in the mouse, not in humans) and TNF-alpha.
Differentiation
In vitro studies on differentiation have used the pre-committed preadipocyte lineage, such as 3T3-L1 and 3T3-F442A cell line, or preadipocytes isolated from the stromal-vascular fraction of white adipose tissue. In vitro differentiation is a highly ordered process. Firstly, proliferating preadipocytes arrest growth usually by contact inhibition. The growth arrest followed by the earliest events, including a morphological change of preadipocyte from the fibroblast-shape to the round-shape and the induction of transcription factors C/EBPβ, and C/EBPδ. The second phase of growth arrest is the expression of two key transcription factors PPARγ and C/EBPα which promote expression of genes that confer the characteristics of mature adipocytes. These genes include adipocyte protein (aP2), insulin receptor, glycerophosphate dehydrogenase, fatty acid synthase, acetyl CoA carboxylase, glucose transporter type 4 (Glut 4) and so on.[6] Through this process, lipid droplets accumulate in the adipocyte. However, preadipocytes cell lines have difficult to different to differentiate into adipocytes. Preadipocytes display CD45− CD31− CD34+ CD29+ SCA1+ CD24+ surface markers can proliferate and differentiate to adipocytes in vivo.[7]
Hind limb muscles of fetal Swiss webster mouse[20]
Ectopic expression of PPAR-gamma + CEBP/alpha +D + I
FBS = Fetal Bovine Serum, D = Dexamethasone, I = Insulin, M = Methylisobutylxanthine T3 = Triiodothyronine
Transcriptional regulations
PPARγ
PPARγ is a member of the nuclear-receptor superfamily and is the master regulator of adipogenesis. PPARγ heterodimerizes with retinoid X receptor (RXR) and then binds to DNA, which activates the promoters of the downstream genes. PPARγ induces fat-cell specific genes, including aP2, adiponectin and phosphoenolpyruvate carboxykinase (PEPCK). PPARg activation has effects on several aspects of the mature adipocyte characteristics such as morphological changes, lipid accumulation, and the acquisition of insulin sensitivity.[21]PPARγ is necessary and sufficient to promote fat cell differentiation. PPARγ is required for embryonic stem cells (ES cells) differentiation to adipocytes.[22] The expression of PPARγ itself is sufficient to convert fibroblast into adipocytes in vitro.[23] Other pro-adipogenic factors like C/EBPs and Krüppel-like factors (KLFs) have been shown to induce the PPARγ promoter. Moreover, PPARγ is also required to maintain the expression of genes that characterize the mature adipocyte.[24] Thiazolidinediones (TZDs), antidiabetic agents which well used differentiation cocktail in vitro, promoting the activity of PPARγ.
C/EBPs
C/EBPs, transcription factors, are members of the basic-leucine zipper class. cAMP, an inducer of adipogenesis, can promote expression of C/EBPβ and C/EBPδ.[25] At the early stage of differentiation, the transient increase of C/EBPβ and C/EBPδ mRNA and protein levels are thought to activate the adipogenic transcription factors, PPARγ and C/EBPα. PPARγ and C/EBPα can feedback to induce the expression of each other as well as their downstream genes.[26]C/EBPα also plays an important role in the insulin sensitivity of adipocytes.[27] However, C/EBPγ suppresses differentiation which might due to inactivation by C/EBPβ.
Transcriptional cascade
Although PPARγ and C/EBPα are master regulators of adipogenesis, other transcription factors function in the progression of differentiation. Adipocyte determination and differentiation factor 1 (ADD1) and sterol regulatory element binding protein 1 (SREBP1) can activate PPARγ by the production of an endogenous PPARγ ligand or directly promote the expression of PPARγ. cAMP-responsive element binding protein promotes differentiation, while the activation of PPARγ and C/EBPα is also responsive to negative regulation. T-cell factor/lymphoid enhancer-binding factor (TCF/LEF),[28] GATA2/3,[29] retinoic acid receptor α,[30] and SMAD6/7[31] don't affect the expression of C/EBPβ and C/EBPδ but inhibit the induction of PPARγ and C/EBPα.
Insulin regulates adipogenesis through insulin-like growth factor 1 (IGF1) receptor signaling. Insulin/IGF1 promotes the induction transcription factors regulating terminal differentiation.
Wnt signaling
Wnt/β-catenin signaling suppresses adipogenesis, by promoting the differentiation of mesenchymal stem cells into myocytes and osteocytes but blocking the commitment to the adipocytic lineage.[35] Wnt/β-catenin inhibits the differentiation of preadipocytes by inhibiting the induction of PPARγ and C/EBPα.
BMPs
Bone morphogenetic proteins (BMPs) are transforming growth factor β (TGFβ) superfamily members. BMP2 can either stimulates the determination of multipotent cells or induce osteogenesis through different receptor heteromers.[36] BMPs also promotes the differentiation of preadipocytes.
Senescent cells
Senescent adipose progenitor cells in subcutaneous adipose tissue has been shown to suppress adipogenic differentiation.[37] Reduced adipogenesis in obese persons is due to increased senescent cells in adipose tissue rather than reduced numbers of stem/progenitor cells.[38]
^Darmon M, Serrero G, Rizzino A, Sato G (April 1981). "Isolation of myoblastic, fibro-adipogenic, and fibroblastic clonal cell lines from a common precursor and study of their requirements for growth and differentiation". Experimental Cell Research. 132 (2): 313–27. doi:10.1016/0014-4827(81)90107-5. PMID7215448.
^Aaronson SA, Todaro GJ (October 1968). "Development of 3T3-like lines from Balb-c mouse embryo cultures: transformation susceptibility to SV40". Journal of Cellular Physiology. 72 (2): 141–8. doi:10.1002/jcp.1040720208. PMID4301006. S2CID31332589.
^Reznikoff CA, Brankow DW, Heidelberger C (December 1973). "Establishment and characterization of a cloned line of C3H mouse embryo cells sensitive to postconfluence inhibition of division". Cancer Research. 33 (12): 3231–8. PMID4357355.
^Tontonoz P, Hu E, Spiegelman BM (December 1994). "Stimulation of adipogenesis in fibroblasts by PPAR gamma 2, a lipid-activated transcription factor". Cell. 79 (7): 1147–56. doi:10.1016/0092-8674(94)90006-x. PMID8001151. S2CID54387527.
Universitas Cambridge Edward Miller (16 Juli 1915 – 21 Desember 2000) adalah seorang sejarawan Inggris terkemuka. Ia mengenyam pendidikan dalam Universitas Cambridge di mana ia belajar sejarah abad pertengahan. Setelah sebuah kesuksesan berkarier dalam dunia akademis dan kehidupan publik, ia terpilih menjadi Master dari Kolese Fitzwilliam, Cambridge selama lebih dari satu dekade, antara 1971 dan 1981. Selama masa tersebut, Miller mengawasi sebuah perkembangan yang signifikan dari kolese ter...
Commune in Brittany, FranceRoscoff Rosko (Breton)CommuneCenter of Roscoff from Sainte Barbe chapel FlagCoat of armsLocation of Roscoff RoscoffShow map of FranceRoscoffShow map of BrittanyCoordinates: 48°44′00″N 3°59′00″W / 48.733333°N 3.983333°W / 48.733333; -3.983333CountryFranceRegionBrittanyDepartmentFinistèreArrondissementMorlaixCantonSaint-Pol-de-LéonIntercommunalityHaut-Léon CommunautéGovernment • Mayor (2020–2026) Odile Th...
Japanese television series He's ExpectingPromotional release posterGenre Comedy drama Based onHiyama Kentarô no Ninshin by Eri SakaiWritten by Yoshitatsu Yamada Yukiko Sode Chihiro Amano Directed by Yuko Hakota (lead) Takeo Kikuchi Starring Takumi Saitoh Juri Ueno ComposerMasaki HayashiCountry of originJapanOriginal languageJapaneseNo. of seasons1No. of episodes8 (list of episodes)ProductionExecutive producer Shinichi Takahashi (Netflix) Producers Yuriko Mamiya (TV Tokyo) Yu Ota (TV Tokyo) T...
National Educational TelevisionLogo National Educational Television.JenisJaringan televisi berlangganan terestrial gratisNegaraAmerika SerikatDidirikan21 November 1952 Washington, D.C., Amerika SerikatMarkasKota New YorkWilayah siarAmerika Serikat dan KanadaPemilikFord Foundation (1954–1970)Corporation for Public Broadcasting (1967–1970)Tanggal luncur16 Mei 1954Ditutup4 Oktober 1970 National Educational Television (disingkat NET) adalah jaringan televisi Amerika Serikat yang dimiliki oleh...
Anne of the Thousand DaysPoster layar lebar asliSutradaraCharles JarrottProduserHal B. WallisSkenarioBridget BolandJohn HaleRichard SokoloveBerdasarkanAnne of the Thousand Days byMaxwell AndersonPemeranRichard BurtonGeneviève BujoldAnthony QuayleJohn ColicosIrene PapasPenata musikGeorges DelerueSinematograferArthur Ibbetson, BSCDistributorUniversal PicturesTanggal rilis 18 Desember 1969 (1969-12-18) (Amerika Serikat) 23 Februari 1970 (1970-02-23) (Britania Raya) Duras...
Ab Tak ChhappanSutradaraShimit AminProduserRam Gopal VarmaDitulis olehSandeep SrivastavaPemeranNana Patekar Mohan Agashe Revathi Hrishitaa BhattPenata musikSalim-SulaimanSinematograferVishal SinhaPenyuntingMurad SiddiquiTanggal rilis 27 Februari 2004 (2004-02-27) Durasi129 minutesNegaraIndiaBahasaHindiMarathiAnggaran₹3 juta (US$42,000) (estimated)Pendapatankotor₹251,5 juta (US$3,5 juta) (14 May 2004) Ab Tak Chhappan (English: Fifty Six So Far) adalah film India produksi ta...
Zambian flag carrier Not to be confused with Zambian Airways. Zambia Airways IATA ICAO Callsign ZN AZB AIR ZAMBIA FoundedApril 1964 (1964-04)Commenced operations1 July 1964 (1964-07-01)HubsKenneth Kaunda International AirportFleet size2Destinations5Parent companyZambian Industrial Development CorporationHeadquartersLusaka, ZambiaWebsitewww.zambia-airways.com Zambia Airways is the flag carrier of the Republic of Zambia. The airline is based in Lusaka, Zambia with its h...
DE10Lokomotif DE10 1765 milik JR East pada September 2015Data teknisSumber tenagaDiesel hidrolikProdusenKisha Seizo, Nippon SharyoTanggal dibuat1966 - 1978Jumlah dibuat708Spesifikasi rodaKlasifikasi UICC'B'DimensiLebar sepur1.067 mm (3 ft 6 in)Diameter roda860 mmPanjang14,150 mmLebar2,950 mmTinggi maksimum3,965 mmBeratBahan bakarSistem mesinKinerjaTransmisiHidrolikDaya mesin1.250 hp (930 kW), 1.350 hp (1.005 kW) (DE10-1000 onward)Lai...
Військово-музичне управління Збройних сил України Тип військове формуванняЗасновано 1992Країна Україна Емблема управління Військово-музичне управління Збройних сил України — структурний підрозділ Генерального штабу Збройних сил України призначений для планува...
Overview of the influence of European colonial powers in Afghanistan This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: European influence in Afghanistan – news · newspapers · books · scholar · JSTOR (June 2013) (Learn how and when to remove this message) Part of a series on the History of Afghanistan Timeline ...
2014 Pure Michigan 400 Race details[1][2][3][4][5][6][7][8][9][10] Race 23 of 36 in the 2014 NASCAR Sprint Cup Series Michigan International SpeedwayDate August 17, 2014 (2014-08-17)Location Michigan International SpeedwayBrooklyn, MichiganCourse Permanent racing facility2.0 mi (3.2 km)Distance 200 laps, 400 mi (640 km)Weather Cloudy with a temperature of 71 °F (22 °C); wind out of the e...
Katalis Adams Nama Nama IUPAC Platina(IV) oksida Nama lain platina dioksida, platini oksida Penanda Nomor CAS 1314-15-4 Y Model 3D (JSmol) Gambar interaktif 3DMet {{{3DMet}}} ChemSpider 306130 Y Nomor EC PubChem CID 345198 Nomor RTECS {{{value}}} UNII 9U12312Y2C Y CompTox Dashboard (EPA) DTXSID40904275 InChI InChI=1S/2O.Pt YKey: YKIOKAURTKXMSB-UHFFFAOYSA-N YInChI=1/2O.Pt/rO2Pt/c1-3-2Key: YKIOKAURTKXMSB-FVLSDXBIAR SMILES O=[Pt]=O Sifat Rumus kimia PtO2 ...
Questa voce o sezione sugli argomenti piazze e Emilia-Romagna non cita le fonti necessarie o quelle presenti sono insufficienti. Puoi migliorare questa voce aggiungendo citazioni da fonti attendibili secondo le linee guida sull'uso delle fonti. Segui i suggerimenti del progetto di riferimento. Piazza GrandeLa piazza nel 1896LocalizzazioneStato Italia CittàModena Informazioni generaliTipopiazza Mappa Modifica dati su Wikidata · Manuale Bene protetto dall'UNESCOCattedral...
Gianni MeersmanMeersman al Tour de l'Ain 2013Nazionalità Belgio Altezza177[1] cm Peso63[1] kg Ciclismo SpecialitàStrada Termine carriera2016 CarrieraSquadre di club 2005Beveren 20002005 Davitamonstagista2006Beveren 20002007 Discovery Channel2008-2010 Française des Jeux2010-2011 FDJ2012 Lotto2013-2014 Omega Pharma2015-2016 Etixx-Quick Step Nazionale 2012 Belgio Carriera da allenatore 2017-2018Marlux2019-2020Pauwels Sauzen2021- Alp...
Status of a book title at a publishing house For the album, see Out of Print (The Forgotten album). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: Out of print – news · newspapers · books · scholar · JSTOR (February 2023) (Learn how and when to remove this message) Advertisement for the 1911 Encyclopædia B...
Questa voce sull'argomento tennisti brasiliani è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Guilherme ClezarClezar a Wimbledon 2015Nazionalità Brasile Altezza183 cm Peso77 kg Tennis Carriera Singolare1 Vittorie/sconfitte 1 – 14 (6.67%) Titoli vinti 0 ATP - 7 ITF Miglior ranking 153º (3 agosto 2015) Risultati nei tornei del Grande Slam Australian Open Q2 (2017) Roland Garros Q3 (2015) Wimbledon Q1 (2013, 2015, 2016, 2018) ...