[Dynamic changes and effect of primary cilia on adipogenesis during 3T3-L1 cell differentiation into adipocytes]

To investigate the dynamic changes and effect of primary cilia on adipogenesis during 3T3-L1 cell differentiation into adipocyte.

Chloral hydrate was applied to inhibit primary cilia on day 0 and 4 of 3T3-L1 cell differentiation into adipocyte. The expression levels of primary cilia key proteins like kinesin family member 3a (Kif3a), intraflagellar transport protein 88 (IFT88), acetylated α-tubulin (acAT) and adipogenic key protein peroxisome proliferator activated receptor γ (PPARγ) were detected by Western blotting. The number of primary cilia was analyzed by immunofluorescence assay. The promoter activity of PPARγ gene was measured with dual-luciferase reporter assay system. The lipid accumulation was observed by oil red O staining.

The levels of primary cilia key proteins, including Kif3a, IFT88, acAT, and the number of the primary cilia were higher on day 0 of cell differentiation, decreased on day 2, and then increased to the beginning levels on day 4, and significantly decreased again on day 8. Incubation with chloral hydrate on day 0 of differentiation significantly reduced the levels of Kif3a, IFT88, acAT proteins and the number of primary cilia, dramatically enhanced the promoter activity of PPARγ gene, level of PPAR γ protein and lipid accumulation. However, although primary cilia was significantly inhibited by the incubation with chloral hydrate on day 4 of differentiation, the promoter activity and protein expression of PPARγ, lipid accumulation had no obvious changes compared with vehicle groups.

Primary cilia presented a dynamic change during 3T3-L1 cell differentiation into adipocytes. Few primary cilia in the early differentiation led to significantly enhanced adipogenesis, but once the differentiation was under way, the decrease of primary cilia would not affect adipogenesis.