Bioinformatic analysis of miRNA mechanisms in circadian rhythm using a zebrafish (Danio Rerio) model

MicroRNAs are noncoding RNAs found in cells and the bloodstream, which help to maintain proper protein production and overall gene expression1. Typically, microRNAs bind to messenger RNA (mRNA) in the cell cytoplasm, acting as post-transcriptional regulators, and either degrade or repress mRNA2. Due to microRNAs playing a vital role in gene expression by repressing protein production of target genes, if they are underexpressed then the protein it regulates could be overexpressed as a result. miRNAs have the potential to be biomarkers for numerous neurodegenerative diseases. Neurodegeneration can be seen in many forms such as Dementia, Alzheimer’s (AD), Huntington’s Disease (HD), Creutzfeldt-Jakob Disease (CJD), Vascular Dementia (VD), Dementia With Lewy Bodies (DLB), and Parkinson\u27s Disease Dementia (PD). Early diagnosis of neurodegenerative disease is difficult due to the inability to analyze the diseased tissue. Tissue in the central nervous system cannot be biopsied without using invasive techniques. miRNAs originating from not easily accessible locations, such as neurons in the brain and spinal cord, have the ability to detect early biomarkers for dementia. With the analysis of miRNAs as biomarkers for dementia, early diagnosis of neurodegeneration may be facilitated. Sleep deprivation (SD) is one of the many side effects, and causes, of neurodegeneration and it adversely affects the circadian physiology3. To investigate abnormal microRNA expression, Danio rerio (zebrafish) will be used as a model organism and will be exposed to altered circadian rhythms in order to mimic SD. Collection of brain tissue from zebrafish will be conducted to assess for dysregulation of miRNAs

MicroRNA Networks in Cognition and Dementia

The change from viewing noncoding RNA as “junk” in the genome to seeing it as a critical epigenetic regulator in almost every human condition or disease has forced a paradigm shift in biomedical and clinical research. Small and long noncoding RNA transcripts are now routinely evaluated as putative diagnostic or therapeutic agents. A prominent role for noncoding microRNAs in the central nervous system has uncovered promising new clinical candidates for dementia-related disorders, treatments for which currently remain elusive even as the percentage of diagnosed patients increases significantly. Cognitive decline is a core neurodegenerative process in Alzheimer’s Disease, Frontotemporal Dementia, Lewy body dementia, vascular dementia, Huntington’s Disease, Creutzfeldt–Jakob disease, and a significant portion of Parkinson’s Disease patients. This review will discuss the microRNA-associated networks which influence these pathologies, including inflammatory and viral-mediated pathways (such as the novel SARS-CoV-2 virus implicated in COVID-19), and their current status in clinical trials