Figure 5.

Expression patterns of selected miRNAs and BDNF in PFC across the lifespan. (A) Heatmap showing relative expression levels presented as quartiles (from higher to lower: red, yellow, green, blue) of (i) control miR-128a not predicted to target BDNF, (ii) 7 microRNAs each predicted to target BDNF and expressed in human PFC (data from qRT–PCR and normalized to 5S rRNA), (iii) average of weighted means of all 7 miRNAs shown in (ii), (iv) BDNF protein as measured by ELISA and (v) BDNF mRNA as measured by qRT–PCR and normalized to 18S rRNA. All samples from human PFC (gray matter, BA10) ranging in age from 21 estimated weeks of gestation (ewg) to 84 years (y). Brain Hemisphere (H), gender (G) and tissue pH (pH) are also shown for each sample. Notice the age-related expression changes of the BDNF-related miRNAs, including the decline in miR-30a levels in late adolescent—young adult group (15–41 years of age), which are distinct from the control miR-128a. (B–D) Bar graph summarizing the developmental expression data shown in (A) for miR-30a (B), BDNF protein (C), and BDNF mRNA levels (D). Graphs represent weighted means ± SEM. (n = 7–15 per age group) normalized to 5S rRNA for miRNAs and to 18S rRNA for BDNF mRNA, for (x-axis) four different age groups ranging from fetal to adult ages (n = 7–15/age group). Notice again the robust decline in miR-30a levels in the group of samples 15–41 years old and the significant increases in BDNF mRNA after birth (0–15 year) and in BDNF protein both after birth and between 15 and 41 years of age (B). *P < 0.05, (ANOVA post hoc Tukey).