title: Expression of clock genes in human subcutaneous and visceral adipose tissues.
abstract: Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41 ± 11 yrs of age) presenting a wide range of BMI (21.4 to 48.6 kg/m(2)) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p < .0001) in SAT in comparison to VAT was PER1 of female (372%) and male (326%) subjects. Different patterns of expression between the AM and PM periods were observed, in particular REV-ERBα, which was reduced (p < .05) at the PM period in SAT and VAT of both women and men (women: ∼53% lower; men: ∼78% lower), whereas CLOCK expression was not altered. Relationships between clock genes were different in SAT vs. VAT. BMI was negatively correlated with SATPER1 (r = -.549; p = .001) and SATPER2 (r = -.613; p = .0001) and positively with VATCLOCK (r = .541; p = .001) and VATBMAL1 (r = .468; p = .007) only in women. These data suggest that the circadian clock machinery of adipose tissue depots differs between female and male subjects, with a sex-specific effect observed for some genes. BMI correlated with clock genes, but at this moment it is not possible to establish the cause-effect relationship.
authors.affiliation: Laboratório de Endocrinologia Celular e Molecular (LIM/25), Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. mzanquetta@gmail.com
authors.forename: Melissa Moreira
authors.initials: MM
authors.lastname: Zanquetta
authors.forename: Maria Lúcia
authors.initials: ML
authors.lastname: Correa-Giannella
authors.forename: Daniel
authors.initials: D
authors.lastname: Giannella-Neto
authors.forename: Paulino Alberto
authors.initials: PA
authors.lastname: Alonso
authors.forename: Ligia Maria Martins Vaz
authors.initials: LM
authors.lastname: Guimarães
authors.forename: Alberto
authors.initials: A
authors.lastname: Meyer
authors.forename: Sandra Mara Ferreira
authors.initials: SM
authors.lastname: Villares
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics; D000328:Adult; D015992:Body Mass Index; D056926:CLOCK Proteins / Q000235:genetics; D057906:Circadian Clocks / Q000235:genetics*; D056931:Cryptochromes / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006801:Humans; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1 / Q000235:genetics; D056950:Period Circadian Proteins / Q000235:genetics; D012727:Sex Characteristics; D050151:Subcutaneous Fat / Q000378:metabolism*
chemical_list: D056930:ARNTL Transcription Factors; C538960:BMAL1 protein, human; C538963:CRY1 protein, human; D056931:Cryptochromes; C064353:NR1D1 protein, human; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; C539022:PER1 protein, human; C421902:PER2 protein, human; D056950:Period Circadian Proteins; D056926:CLOCK Proteins; C538943:CLOCK protein, human