Fig. 5. Isomer-specific regulation of MEK/ERK signaling by CLA.

Cultures of SV cells containing newly differentiated human adipocytes were serum starved for 24 h and then treated (TRT) for the indicated time points with the indicated treatments. A, cultures were treated with 30 μm trans-10, cis-12 CLA for 30 min, 4 h, or 24 h. A 30-min treatment with TNF-α was used as a positive control for MAPK activation. Cell extracts were immunoblotted for the phosphorylated forms of p38 MAPK, JNK-MAPK, or p44/p42 (ERK1/2) MAPK. B, cultures were treated acutely (≤24 h) or chronically (12–72 h) with either a BSA vehicle or 30 μm trans-10, cis-12 CLA complexed to BSA. Cell extracts were immunoblotted for the phosphorylated forms of the MAPK kinase (P-MEK) and p44/p42 extracellular signal-related MAPK (P-ERK1/2) and subsequently were stripped and reprobed with antibodies recognizing total MEK (MEK), and total ERK (ERK1/2). C, cultures were treated with either a BSA vehicle (B), 30 μm cis-9, trans-11 CLA (9), or 30 μm trans-10, cis-12 CLA (10) complexed to BSA for 24–72 h. Cell extracts were immunoblotted for P-MEK, P-ERK1/2, total MEK, and total ERK1/2. Data shown are representative of three to seven independent experiments for each panel.