Tools for investigating the intra-axonal roles of miRNAs. (a) Schematics for distal axons isolation: Campenot chambers, microfluidic devices or manual removal of the explants in case of organoculture. (b) Techniques for studying miRNA function: by loss of function (LOF) approach blocking miRNA function (1–3), by gain of function (GOF) approach increasing miRNAs level with mimics (4); by blocking miRNA target recognition, masking the miRNA-responsive element (MREs) with a target protector (5); by studying with reporters the translational events potentially regulated by the miRNA under study (6,7); by measuring the miRNA activity using sensor plasmids (8). Abbreviations: ORF, open reading frame; ASOs, antisense oligonucleotides.