Modulation by Cocaine of Dopamine Receptors through miRNA-133b in Zebrafish Embryos

Abstract

The use of cocaine during pregnancy can affect the mother and indirectly might alter the development of the embryo/foetus. Accordingly, in the present work our aim was to study in vivo (in zebrafish embryos) the effects of cocaine on the expression of dopamine receptors and on miR-133b. These embryos were exposed to cocaine hydrochloride (HCl) at 5 hours post-fertilization (hpf) and were then collected at 8, 16, 24, 48 and 72 hpf to study the expression of dopamine receptors, drd1, drd2a, drd2b and drd3, by quantitative real time PCR (qPCR) and in situ hybridization (ISH, only at 24 hpf). Our results indicate that cocaine alters the expression of the genes studied, depending on the stage of the developing embryo and the type of dopamine receptor. We found that cocaine reduced the expression of miR-133b at 24 and 48 hpf in the central nervous system (CNS) and at the periphery by qPCR and also that the spatial distribution of miR-133b was mainly seen in somites, a finding that suggests the involvement of miR-133b in the development of the skeletal muscle. In contrast, at the level of the CNS miR-133b had a weak and moderate expression at 24 and 48 hpf. We also analysed the interaction of miR-133b with the Pitx3 and Pitx3 target genes drd2a and drd2b, tyrosine hydroxylase (th) and dopamine transporter (dat) by microinjection of the Pitx3-3'UTR sequence. Microinjection of Pitx3-3'UTR affected the expression of pitx3, drd2a, drd2b, th and dat. In conclusion, in the present work we describe a possible mechanism to account for cocaine activity by controlling miR-133b transcription in zebrafish. Via miR-133b cocaine would modulate the expression of pitx3 and subsequently of dopamine receptors, dat and th. These results indicate that miRNAs can play an important role during embryogenesis and in drug addiction.

Epigenetic Signaling in Psychiatric Disorders

“…These expression changes were accompanied by decreased miR-133b, in both encephalon and in the periphery 191 . It will be interesting to validate these findings in mammalian systems and test whether miR-133b may be a useful biomarker for changes occurring within the developing brain reward circuitry.…”

“…Prenatal cocaine exposure in zebrafish altered mRNA levels of Drd1 , Drd2a , Drd2b , and Drd3 , Pitx3 , and Th , genes known to be relevant for drug taking behavior 191 . These expression changes were accompanied by decreased miR-133b, in both encephalon and in the periphery 191 .…”

Noncoding RNA Regulation of Dopamine Signaling in Diseases of the Central Nervous System

“…Parallel changes of dopamine and serotonin in this model is consistent with extensive cross-talk reported in synaptic signaling (Henstridge et al, 2016). Further, an independent study found this miRNA pathway is altered in another neuropsychiatric disorder, cocaine addiction (Barreto-Valer et al, 2012). Zebrafish embryos were exposed to cocaine followed by gene expression analysis at various developmental timepoints.…”

Zebrafish as an innovative model for neuroendocrine tumors

“…In zebrafish, 8 dopamine receptors have been cloned (Barreto-Valer et al 2012): D1-like receptor (Drd1), which shares 71% amino acid identity to humans (Li et al 2007); the D2-like receptors (Drd2a, Drd2b, Drd2c, Drd3, Drd4a, Drd4b, and Drd4rs), which show an amino acid identity with human sequence ranging 56-67% (Boehmler et al 2004(Boehmler et al , 2007.…”