cis9, trans11-Conjugated Linoleic Acid Differentiates Mouse 3T3-L1 Preadipocytes into Mature Small Adipocytes through Induction of Peroxisome Proliferator-activated Receptor γ

Dietary conjugated linoleic acid (CLA) has been reported to exhibit a number of therapeutic effects in animal models and patients, such as anti-hypertensive, anti-hyperlipidemic, anti-arteriosclerotic, anti-carcinogenic, and anti-diabetic effects. However, the underlying mechanism is not well-characterized. In the present study, the effects of cis(c)9, trans(t)11-CLA on the differentiation of mouse 3T3-L1 preadipocytes into mature adipocytes were examined. Treatment with c9, t11-CLA in the presence of insulin, dexamethasone, and 3-isobutyl-1-methyl-xanthine (differentiation cocktail) significantly stimulated the accumulation of triacylglycerol. The microscopic observation of cells stained by Oil Red O demonstrated that c9, t11-CLA increases the amount and proportion of small mature adipocytes secreting adiponectin, a benign adipocytokine, when compared to the differentiation cocktail alone. Furthermore, c9, t11-CLA increased bioactive peroxisome proliferator-activated receptor γ (PPARγ) levels in a nuclear extract of 3T3-L1 cells, suggesting the enhancing effect of this fatty acid on the nuclear transmission of PPARγ, a master regulator of adipocyte differentiation, in 3T3-L1 cells. These results suggest that the therapeutic effects of c9, t11-CLA on lifestyle-related diseases are partially due to the enhanced formation of small adipocytes from preadipocytes via PPARγ stimulation

A Novel Role for hGas7b in Microtubular Maintenance: POSSIBLE IMPLICATION IN TAU-ASSOCIATED PATHOLOGY IN ALZHEIMER DISEASE*

Here, we report a novel role for hGas7b (human growth arrest specific protein 7b) in the regulation of microtubules. Using a bioinformatic approach, we studied the actin-binding protein hGas7b with a structural similarity to the WW domain of a peptidyl prolyl cis/trans isomerase, Pin1, that facilitates microtubule assembly. Thus, we have demonstrated that hGas7b binds Tau at the WW motif and that the hGas7b/Tau protein complex interacts with the microtubules, promoting tubulin polymerization. Tau, in turn, contributes to protein stability of hGas7b. Furthermore, we observed decreased levels of hGas7b in the brains from patients with Alzheimer disease. These results suggest an important role for hGas7b in microtubular maintenance and possible implication in Alzheimer disease