MicroRNAs (miRNAs) are short RNA molecules that modulate post-transcriptional gene expression by partial or incomplete base-pairing to the complementary sequences on their target genes. Sequence-ba...

Germline mutations in Mir96, one of three co-expressed polycistronic miRNA genes (Mir96, Mir182, Mir183), cause hereditary hearing loss in humans and mice. Transgenic FVB/NCrl- Tg(GFAP-Mir183,Mir96,Mir182)MDW1 mice (Tg^1MDW), which overexpress this neurosensory-specific miRNA cluster in the inner ear, were developed as a model system to identify, in the aggregate, target genes and biologic processes regulated by the miR-183 cluster. Histological assessments demonstrate Tg^1MDW/1MDW homozygotes have a modest increase in cochlear inner hair cells (IHCs). Affymetrix mRNA microarray data analysis revealed that downregulated genes in P5 Tg^1MDW/1MDW cochlea are statistically enriched for evolutionarily conserved predicted miR-96, miR-182 or miR-183 target sites. ABR and DPOAE tests from 18 days to 3 months of age revealed that Tg^1MDW/1MDW homozygotes develop progressive neurosensory hearing loss that correlates with histologic assessments showing massive losses of both IHCs and outer hair cells (OHCs). This mammalian miRNA misexpression model demonstrates a potency and specificity of cochlear homeostasis for one of the dozens of endogenously co-expressed, evolutionally conserved, small non-protein coding miRNA families. It should be a valuable tool to predict and elucidate miRNA-regulated genes and integrated functional gene expression networks that significantly influence neurosensory cell differentiation, maturation and homeostasis.

Oral health is crucial to overall health, and periodontal disease (PDD) is a chronic inflammatory disease. Over the past decade, PDD has been recognized as a significant contributor to systemic inflammation. Here, we relate our seminal work defining the role of lysophosphatidic acid (LPA) and its receptors (LPARs) in the oral system with findings and parallels relevant to cancer. We discuss the largely unexplored fine-tuning potential of LPA species for biological control of complex immune responses and suggest approaches for the areas where we believe more research should be undertaken to advance our understanding of signaling at the level of the cellular microenvironment in biological processes where LPA is a key player so we can better treat diseases such as PDD, cancer, and emerging diseases.