MicroRNA-22 regulates thyroid cell growth and lipid accumulation via IL6R.

Thyroid stimulating hormone (TSH) is the main regulator of thyroid cell proliferation and endocrine function. Here, we tested the effect of mir-22 in TSH induced proliferation and lipid metabolism of thyroid cells. TSH significantly down-regulated miR-22-3p, promoted proliferation and inhibited apoptosis of thyroid epithelial cells line, FRTL-5; effects that were opposed by overexpression of miR-22-3p. Overexpression of miR-22-3p significantly inhibited TSH- induced expression of lipid metabolic marker genes and increased the expression of lipid catabolism markers and IL6R and led to accumulation of intracellular lipid. IL6R overexpression also led to excessive proliferation, restrained apoptosis and promoted lipid accumulation. In conclusion, miR-22 regulates TSH-induced thyroid cell proliferation and lipid metabolism disorder by impacting IL6R.