Supplementary Material for: Alterations in serum miR-126-3p levels over time, a marker of pituitary insufficiency following head trauma

TBI is a condition caused by a head injury that poses a high risk of developing pituitary insufficiency in patients. We have previously reported alterations in miR-126-3p levels in sera from patients with TBI-induced pituitary deficiency. To investigate why TBI-induced pituitary deficiency develops in only some patients and to reveal the relationship of miR-126-3p with the hormone axes, we used mice epigenetically modified with miR-126-3p at the embryonic stage in this study. These modified mice were subjected to mild-TBI(mTBI) according to the Marmarou-weight-drop model. The alterations of miR-126-3p levels after mTBI of both wild-type and modified-miR-126-3p* lines of mice validated our human results. In addition, the hypothalamus, pituitary, and adrenal tissues were analyzed for the related transcripts and serum hormone levels.
We report that mir-126-3p directly affects the upregulation of the Hypothamus-Pituitary-Adrenal (HPA) axis and ACTH secretion in the acute phase after mTBI. We have also demonstrated that miR-126-3p suppresses Gnrh transcripts in the hypothalamus and pituitary, but this is not reflected in FSH/LH serum levels. The increase in ACTH levels in the acute phase may indicate that the up-regulation of miR-126-3p has a protective effect on the HPA axis after TBI. Notably, the most prominent transcript response is found in the adrenals, highlighting their role in the pathophysiology of TBI. Our study revealed the role of miR-126-3p in TBI and pituitary deficiency developing after TBI, and the data obtained will significantly contribute to unraveling the mechanism of pituitary deficiency developing after TBI and developing new diagnostic and treatment strategies.