TLR7 and neuroblastoma: To confirm the injurious effects of let-7 miRNAs on human-derived neurons and to ensure that the observed degenerative effects were cell-autonomous and not due to contamination with other cells, e.g. microglia, human neuroblastoma SH-SY5Y cells, which express TLR7 (S7 Fig), were incubated with various doses of let-7b and let-7e that were present at high copy levels in AD and MDE CSF (Fig 5D and 5E).