BDNF and central nervous system disorder: In brain tissue, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a common environmental contaminant, induced the over-expression of miR-206, miR-30 and miR-195, which then inhibited the expression of the target BDNF gene and contributed to neuro-toxicity and CNS disorders.