Table 2:
Micro-RNAs affecting axonal growth
| Neuron/tissue source | Approach | Pathway (Target mRNAs) | Reference |
|---|---|---|---|
| Spinal cord (36 miRs) – T12-T13 spinal cord contusion (1–14 days after-injury) | Microarray | De-differentiation of surviving neurons, emergent activation of stem cell niches. | (Strickland et al., 2011a) |
| DRGs (20 miRs) –sciatic nerve transection (7 days after-injury) | Microarray | Ras/Raf/ERK [Sprouty 2 (miR-21)] | (Strickland et al., 2011b) |
| DRGs (21 miRs)- sciatic nerve transection – (7 days after-injury) | Microarray | Slit-Robo-srGAP [Robo2 (miR-145), srGAP (miR-214)] | (Zhang et al., 2011) |
| DRGs (201 miRs) and Proximal stump (225 miRNAs) – sciatic nerve transection (0–14 days after-injury) | RNA-seq | Intrinsic growth capacity, Schwann cellneuron communication | (Yu et al., 2011) |
| DRGs (26 miRs) - sciatic nerve transection (0–14 days after-injury) | Microarray | cAMP/CREB-based signaling [Pten (miR-222)] | (Zhou et al., 2011) |
| DRGs (19 miRs) – sciatic nerve crush (4 days after-injury) | Microarray | Wnt/β-catenin signaling pathway [Kremen 1 (miR-431)] | (Wu and Murashov, 2013) |
| DRGs (49 miRs) – sciatic nerve crush (7 days after-injury) | RNA-seq | Morphogenesis, polarity, GTPase regulatory activity, actin cytoskeleton reorganization and neural tube formation | (Motti et al., 2017) |
| Sciatic nerve axoplasm (141 miRs; 10 pre-miRNA) – sciatic nerve crush (miRs: 1–14 days after-injury; pre-miRNA: 7 days after-injury) | RNA-seq | ER stress response, cytoskeleton dynamics, vesicle formation | (Kim et al., 2015a; Phay et al., 2015) |
*
Note that recent work from this group has also detected piRNAs in axons, though the functions of these slight larger ncRNAs in axons is not yet clear (Phay et al., 2018).