PPARgamma activity in subcutaneous abdominal fat tissue and fat mass gain during short-term overfeeding.

OBJECTIVE: As the peroxisome proliferator-activated receptor gamma (PPARgamma) plays a central role in fat mass regulation, we investigated whether initial subcutaneous PPARgamma activity is related to fat mass generation during overfeeding. SUBJECTS: Fourteen healthy female subjects (age 25 +/- 4 years, BMI 22.1 +/- 2.3 kg/m2). DESIGN AND MEASUREMENTS: Subjects were overfed with a diet supplying 50% more energy than baseline energy requirements for 14 days. Fasting blood samples were analyzed for leptin, insulin and glucose. Fasting subcutaneous abdominal fat biopsies were obtained for analysis of PPARgamma1, PPARgamma2, aP2 and UCP2 mRNAs. RESULTS: Initial PPARgamma1 and 2, aP2 and UCP2 mRNAs were not related to fat gain (P > 0.12). However, PPARgamma1, PPARgamma2 and aP2 mRNA changes were positively related to changes in plasma leptin (P < 0.05) and, except aP2 (P = 0.06), to fat gain (P < 0.05). PPARgamma and aP2 mRNA changes were positively related (P<0.01), indicating that PPARgamma mRNA levels reflected PPARgamma activity. CONCLUSION: These data suggest that the ability to increase PPARgamma activity might be involved in the susceptibility to gain weight during a positive energy balance.

An alternative splicing product of the lamin A/C gene lacks exon 10.

Expression of the A-type lamins was studied in the lung adenocarcinoma cell line GLC-A1. A-type lamins, consisting of lamin A and C, are two products arising from the same gene by alternative splicing. Northern blotting showed in GLC-A1 a relatively low expression level of lamin C and an even lower expression level of lamin A as compared to other adenocarcinoma cell lines. Immunofluorescence studies revealed highly irregular nuclear inclusions of lamin A, suggesting protein or gene expression abnormalities. Reverse transcriptase-polymerase chain reaction-based cDNA analysis followed by sequencing indicated the presence of an as yet unidentified alternative splicing product of the lamin A/C gene. This product differs from lamin A by the absence of the 5' part of exon 10 (90 nucleotides). Therefore we propose to designate this product lamin Adelta10. Deletion of the 30 amino acids encoded by exon 10 was predicted to result in a shift in pI of the protein from 7.4 to approximately 8.6, which was confirmed by two-dimensional immunoblotting. mRNA analysis in a variety of cell lines, normal colon tissue as well as carcinomas demonstrated the presence of lamin Adelta 10 in all samples examined, suggesting its presence in a variety of cell types.