Insulin-like growth factor 1 differentially affects lithium sensitivity of lymphoblastoid cell lines from lithium responder and non-responder bipolar disorder patients

Milanesi E;Hadar A;Maffioletti E;Werner H;Shomron N;Gennarelli M;Schulze TG;Costa M;DEL ZOMPO, MARIA;SQUASSINA, ALESSIO;Gurwitz D.

2015-01-01

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Abstract

Bipolar disorder (BD) is a chronic psychiatric illness with an unknown etiology. Lithium is considered the cornerstone in the management of BD, though about 50–60 % of patients do not respond sufficiently to chronic treatment. Insulin-like growth factor 1 (IGF1) has been identified as a candidate gene for BD susceptibility, and its low expression has been suggested as a putative biomarker for lithium unresponsiveness. In this study, we examined the in vitro effects of insulin-like growth factor 1 (IGF-1) on lithium sensitivity in lymphoblastoid cell lines (LCLs) from lithium responder (R) and non-responder (NR) bipolar patients. Moreover, we evaluated levels of microRNA let-7c, a small RNA predicted to target IGF1. We found that exogenous IGF-1 added to serum-free media increased lithium sensitivity selectively in LCLs from NR BD patients. However, no significant differences were observed when comparing let-7c expression in LCLs from R vs. NR BD patients. Our data support a key role for IGF-1 in lithium resistance/response in the treatment of bipolar disorder.