SUMMARY The molecular basis of the earliest neuronal changes that lead to Alzheimer’s disease (AD) is unclear. Here, we analyze neural cells derived from sporadic AD (SAD), APOE4 gene-edited and control induced pluripotent stem cells (iPSCs). We observe major differences in iPSC-derived neural progenitor (NP) cells and neurons in gene networks related to neuronal differentiation, neurogenesis, and synaptic transmission. The iPSC-derived neural cells from SAD patients exhibit accelerated neural differentiation and reduced progenitor cell renewal. Moreover, a similar phenotype appears in NP cells and cerebral organoids derived from APOE4 iPSCs. Impaired function of the transcriptional repressor REST is strongly implicated in the altered transcriptome and differentiation state. SAD and APOE4 expression result in reduced REST nuclear translocation and chromatin binding, and disruption of the nuclear lamina. Thus, dysregulation of neural gene networks may set in motion the pathologic cascade that leads to AD.

MicroRNAs (miRNA) are 21-23 nucleotide molecules not translated into proteins that bind and target the 3' untranslated regions of mRNA. These characteristics make them a possible tool for inhibiting protein translation. Different cellular pathways involved in cancer development, such as cellular proliferation, apoptosis, and migration, are regulated by miRNAs. The objective of this review is to discuss various miRNAs involved in breast cancer in detail as well as different therapeutic strategies from the clinic to industry. A comprehensive discussion is provided on various miRNAs involved in breast cancer development, progression, and metastasis as well as the roles, targets, and related therapeutic strategies of different miRNAs associated with breast cancer. miRNAs known to be clinically useful for the diagnosis and prognosis of breast cancer are also discussed. Different strategies and challenges, including nucleic acid-based (miRNA mimics, antagomiRs, and miRNA sponges) and drug-based (drug resistance, drugs/miRNA interaction, nanodelivery, and sensing systems) approaches to suppress specific oncogenes and/or activate target tumor suppressors are discussed. In contrast to other articles written on the same topic, this review focuses on the therapeutic and clinical value of miRNAs as well as their corresponding targets in order to explore how these strategies can overcome breast cancer, which is the second most frequent type of cancer worldwide. This review focuses on promising and validated miRNAs involved in breast cancer. In particular, two miRNAs, miR-21 and miR-34, are discussed as the most promising targets for RNA-based therapy in non-invasive and invasive breast cancer, respectively. Finally, relevant and commercialized therapeutic strategies are highlighted.

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BackgroundMicroRNAs (miRNAs) are small non-coding RNAs that can exert multilevel inhibition/repression at a post-transcriptional or protein synthesis level during disease or development. Characterisation of miRNAs in adult mammalian brains by deep sequencing has been reported previously. However, to date, no small RNA profiling of the developing brain has been undertaken using this method. We have performed deep sequencing and small RNA analysis of a developing (E15.5) mouse brain.ResultsWe identified the expression of 294 known miRNAs in the E15.5 developing mouse brain, which were mostly represented by let-7 family and other brain-specific miRNAs such as miR-9 and miR-124. We also discovered 4 putative 22-23 nt miRNAs: mm_br_e15_1181, mm_br_e15_279920, mm_br_e15_96719 and mm_br_e15_294354 each with a 70-76 nt predicted pre-miRNA. We validated the 4 putative miRNAs and further characterised one of them, mm_br_e15_1181, throughout embryogenesis. Mm_br_e15_1181 biogenesis was Dicer1-dependent and was expressed in E3.5 blastocysts and E7 whole embryos. Embryo-wide expression patterns were observed at E9.5 and E11.5 followed by a near complete loss of expression by E13.5, with expression restricted to a specialised layer of cells within the developing and early postnatal brain. Mm_br_e15_1181 was upregulated during neurodifferentiation of P19 teratocarcinoma cells. This novel miRNA has been identified as miR-3099.ConclusionsWe have generated and analysed the first deep sequencing dataset of small RNA sequences of the developing mouse brain. The analysis revealed a novel miRNA, miR-3099, with potential regulatory effects on early embryogenesis, and involvement in neuronal cell differentiation/function in the brain during late embryonic and early neonatal development.