Nr3C1-Bhlhb2 Axis Dysregulation Is Involved in the Development of Attention Deficit Hyperactivity.

Abstract

Attention deficit hyperactivity disorder (ADHD) is a child developmental and behavioral disorder which seriously hinders their education and development. To investigate the key regulators in the prefrontal cortex (PFC), the major affected areas of ADHD, microRNA (miR)-138,138*, 34c*, 296, and 494, were noted for their significant downregulation in ADHD model rats spontaneously hypertensive rats (SHRs) compared to Wistar Kyoto (WKY) rat control. Based on promoter sequence analysis and activity assay, glucocorticoid receptor (Nr3c1) was identified for the inhibition of the promoter activity of miR-138-1, 34c*, 296, and 494 genes and their transcription. In the PFC of ADHD model rats SHR, Nr3c1 expression was abnormally elevated and reversely correlated with the levels of miR-138-1, 34c, 296, and 494 expression. Luciferase report assays indicated that all miR-138, 138*, 34c*, 296, and 494 targeted the 3' untranslated region of transcription factor Bhlhb2 (Bhlhe40) messenger RNA (mRNA) in common and ectopic expression of miR-138,138*, 34c*, 296, and 494 further suppressed the expression of Bhlhb2 gene. Consistently, Bhlhb2 expression was significantly higher in PFC of ADHD model SHR than control. Overexpressed Bhlhb2 in vitro significantly suppressed PC12 cell differentiation, and silence of Bhlhb2 enhanced the growth of neurite axon and dendrite. To observe the roles of Bhlhb2 further in vivo, Bhlhb2 was silenced in the PFC of nine SHR rats. Interestingly, knockdown of Bhlhb2 significantly improved the hyperactivity behaviors in SHRs compared to control. These findings show that Nr3c1-Bhlhb2 axis dysregulation was involved in the development of attention deficit and hyperactivity.

• Authors: Li Hui Wu, Wei Cheng, Mei Yu, Bao Mei He, Hui Sun, Qi Chen, Yi Wei Dong, Xiao Ting Shao, Qian Qian Cai, Min Peng, Xing Zhong Wu
• Journal: Molecular neurobiology (Mol Neurobiol) Vol. 54 Issue 2 Pg. 1196-1212 (03 2017) ISSN: 1559-1182 [Electronic] United States
• PMID: 26820676 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Basic Helix-Loop-Helix Transcription Factors
• Bhlhe40 protein, rat
• Homeodomain Proteins
• NR3C1 protein, rat
• Receptors, Glucocorticoid

Topics

• Animals
• Attention Deficit Disorder with Hyperactivity (genetics, metabolism, physiopathology)
• Basic Helix-Loop-Helix Transcription Factors (biosynthesis, genetics)
• Gene Regulatory Networks (physiology)
• HEK293 Cells
• Homeodomain Proteins (biosynthesis, genetics)
• Humans
• Male
• PC12 Cells
• Prefrontal Cortex (metabolism, physiopathology)
• Rats
• Rats, Inbred SHR
• Rats, Inbred WKY
• Receptors, Glucocorticoid (biosynthesis, genetics)