title: Fat accumulation in differentiated brown adipocytes is linked with expression of Hox genes.
abstract: Homeobox (Hox) genes are involved in body plan of embryo along the anterior-posterior axis. Presence of several Hox genes in white adipose tissue (WAT) and brown adipose tissue (BAT) is indicative of involvement of Hox genes in adipogenesis. We propose that differentiation inducing agents viz. isobutyl-methyl-xanthine (IBMX), indomethacin, dexamethasone (DEX), triiodothyronine (T3) and insulin may regulate differentiation in brown adipose tissue through Hox genes. In vitro culture of brown fat stromalvascular fraction (SVF) in presence or absence of differentiation inducing agents was used for establishing relationship between fat accumulation in differentiated adipocytes and expression of Hox genes. Relative expression of Pref1, UCP1 and Hox genes was determined in different stages of adipogenesis. Presence or absence of IBMX, indomethacin and DEX during differentiation of proliferated pre-adipocytes resulted in marked differences in expression of Hox genes and lipid accumulation. In presence of these inducing agents, lipid accumulation as well as expression of HoxA1, HoxA5, HoxC4 &HoxC8 markedly enhanced. Irrespective of presence or absence of T3, insulin down regulates HoxA10. T3 results in over expression of HoxA5, HoxC4 and HoxC8 genes, whereas insulin up regulates expression of only HoxC8. Findings suggest that accumulation of fat in differentiated adipocytes is linked with expression of Hox genes.
authors.affiliation: Animal Biochemistry Division, National Dairy Researikch Institute, Karnal, Haryana, 132001, India.
authors.forename: Smita
authors.initials: S
authors.lastname: Singh
authors.affiliation: Animal Biochemistry Division, National Dairy Researikch Institute, Karnal, Haryana, 132001, India. Electronic address: ys_rajput@rediffmail.com.
authors.forename: Yudhishthir S
authors.initials: YS
authors.lastname: Rajput
authors.affiliation: Dairy Chemistry Division, National Dairy Research Institute, Karnal, Haryana, 132001, India.
authors.forename: Amit K
authors.initials: AK
authors.lastname: Barui
authors.affiliation: Dairy Chemistry Division, National Dairy Research Institute, Karnal, Haryana, 132001, India.
authors.forename: Rajan
authors.initials: R
authors.lastname: Sharma
authors.affiliation: Animal Biotechnology Centre, National Dairy Research Institute, Karnal, Haryana, 132001, India.
authors.forename: Tirtha K
authors.initials: TK
authors.lastname: Datta
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000008:administration & dosage; D052437:Adipocytes, Brown / Q000187:drug effects / Q000378:metabolism*; D050156:Adipogenesis / Q000187:drug effects / Q000235:genetics; D000273:Adipose Tissue / Q000187:drug effects / Q000254:growth & development*; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D003907:Dexamethasone / Q000008:administration & dosage; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D007213:Indomethacin / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism; D051379:Mice; D010750:Phosphoproteins / Q000096:biosynthesis*; D014157:Transcription Factors / Q000096:biosynthesis*; D014284:Triiodothyronine / Q000008:administration & dosage / Q000378:metabolism; D000099261:Homeobox A1 Protein
chemical_list: D015056:1-Methyl-3-isobutylxanthine; D003907:Dexamethasone; D018398:Homeodomain Proteins; D007213:Indomethacin; D007328:Insulin; D010750:Phosphoproteins; D014157:Transcription Factors; D014284:Triiodothyronine; D000099261:Homeobox A1 Protein; C059637:Hoxa5 protein, mouse; C490904:Hoxc4 protein, mouse; C489816:Hoxc8 protein, mouse
keywords: Adipogenesis; Brown fat differentiation; Hox genes; Induction medium; Insulin; Triiodothyronine