Non-coding RNAs known as microRNAs (miRNAs) are serious post-transcriptional gene controllers in a variety of neuronal degenerative disorders and are main in these physiological advancements. The lives and fitness of all people are seriously vulnerable by neurodegenerative conditions, including multiple sclerosis, Parkinson’s disease, Alzheimer’s disease, Huntington’s syndrome, and stroke. Given a number of recent study, some miRNAs can both role as biomarkers to prediction the conditions related with neuronal disorders and direct the progress of neurodegenerative diseases. In animal and cell models, endogenous miRNAs including miR-9, the miR-29 family, miR-15, and the miR-34 family are typically dysregulated. By disturbing a number of pathways and regulating many molecular targets, they are involved in directing the biological and biochemical processes in the nervous system. These miRNAs possibly will be used in future research to identify possible biomarkers for neurodegenerative illnesses, which may make them good candidates for therapeutic targeting(Li et al., 2023). Neural progenitor cells and neural stem cells cannot grow lacking of miRNAs. In case, the vastly expressed brain transcripts miR-9 and miR-124 are both affluent. By delaying the Toll-like receptor 4 pathway, high expression of miR-124 in neural precursor cells and neural stem cells initiates neurogenesis. In the intervening time, miR-124 can trigger microglia by targeting vesicle-associated membrane protein 3 and can also target the Tal1 axis to stimulate neuronal growth. Besides, miR-9 targets the nuclear receptor TLX, which accelerates the variation procedure and promotes glial and neuronal development. The growth and development of neurites, development of neurons, and the occurrence of synapses cartel to integrate nervous system activities and helpfully to regulate the body’s complex activity. In the meantime, miRNA is vital to each of these procedures. For example, dendritic spine development and dendritic growth are mediated by miR-132/miR-212 clusters. Additionally, the brain-specific expression of miR-134 goals LIM kinase 1, which stops dendritic spine growth and increases synaptic excitatory part. The dicer enzyme is important to the production of miRNAs (Song & Rossi, 2017). Neurodegenerative diseases ultimately end from the incapability to produce miRNAs caused by the elimination of the Dicer enzyme and knockdown of certain brain areas (Chmielarz et al. 2017). For example, in separated developed Purkinje cells, Dicer knockdown via Pcp2 promoter–Cre recombinase would end in cerebellar collapse and ataxia (Schaefer et al. 2007). This could be related to the downregulation of miRNAs that target spinal cerebellar ataxin 1, such as miR-130, miR-9, and miR-101 (Lee et al. 2008). MiRNAs are involved in many parts of the growth and development of brain tissue because a number of events, including transcription, maturation, and degradation, disturb the degree of miRNA expression (Diaz et al. 2014). A well controlling mechanism regulates the expression level of miRNA to make guaranteed that it is raised or downregulated through particular stages of biological development (J. Wang et al. 2020a, b). According to Bak et al. (2008), miRNA expression levels in the CNS is asymmetrical and limited. According to Shu et al. (2019), the expression level of some miRNAs varies with cell production, regional differentiation, and pathway formation during cortical development. Many miRNAs are expressed in the brain only occur during growth and development. The levels of miR-178, miR-125b, miR-9, and miR-131 touched their highest levels on embryonic day 21 of the embryonic development, while the levels of miR-124a and miR-266 upregulated during the embryonic stage growth and persist in a stable state after birth, and the expression levels of miR-103 rises over time, according to study conducted to investigate the development of the mouse cortex (Sempere et al. 2004). An embryo’s nervous system develops both physically and continually (de Lahunta et al. 2016). According to Braoudaki and Lambrou (2015), miRNAs might play an important role in monitoring the temporal and spatial growth outlines of the developing nervous system in the brain. For instance, miRNAs in the Hox gene cluster disturb the expression levels of the Hox gene, which in turn regulates the anterior and posterior growth modes of brain tissue. The Hox gene is associated in both of these growth modes.
(Mallo and Alonso 2013; Pearson et al. 2005).