Non-coding RNAs (ncRNAs) are functional RNA molecules that are transcribed from mammalian genome but lack protein coding capacity. Nearly 80% of the human genome constitutes non-coding elements such as small non-coding RNAs, sncRNAs (miRNA, piRNA, SiRNA, SnRNA) and long non-coding RNAs, lncRNAs (linc RNA, NAT, eRNA, circ RNA, ceRNAs, PROMPTS). These ncRNAs have been extensively studied and are known to mediate the regulation of gene expression. In recent decades, lncRNAs have emerged as pivotal molecules that participate in the post-transcriptional regulation by acting as a signal, guide, scaffold and decoy molecules in addition to their role(s) in transcription. ncRNAs are known to play critical roles in defining DNA methylation patterns, imprinting as well as chromatin remodeling, thus having a substantial effect in epigenetic signaling. The expression of lncRNAs is regulated in a tissue specific and developmental stage specific manner and their mis-regulation is often associated with tumorigenesis. Henceforth, this chapter focuses mainly on the role(s) of ncRNAs in transcriptional and post-transcriptional regulation and their relevance in cancers.
Single-nucleotide polymorphisms (SNPs) are implicated in the complexity of understanding the genetics of diseases and their therapeutics. Here we have attempted to determine the impact of nonsynonymous SNPs (nsSNPs) on structure, dynamics, and ligand-binding properties of the human acetylcholinesterase (hAChE) protein, which has been targeted in the treatment of Alzheimer's disease. Of the reported 153 SNPs, 4 nsSNPs, namely, A415G, P104A, V302E, and Y119H, were prioritized to be functionally unfavorable by SIFT and PolyPhen algorithms. Molecular dynamics simulation revealed these nsSNP forms to be structurally stable, and they are also considered functionally active as they lie away from the catalytic triad. However, the aromatic amino acids lining the active-site gorge exhibited altered degrees of side chain dihedral angles. Such conformational alterations were evaluated for their ability to interfere with binding of hAChE inhibitors. The inhibitors (donepezil, galantamine, rivastigmine, and tacrine) were oriented differently in comparison to the native because of the steric hindrance offered by the altered dihedral angles. Interestingly, huperzine A alone exhibited higher efficiency in its binding to the AChE and retained similar orientation irrespective of the polymorphisms since the orientation of Asp74 involved in its binding and trafficking remained unaltered in all protein forms. Therefore, we conclude that nsSNPs confer changes to the dynamicity of proteins, which in turn affects their ligand-binding properties rather than their stability. Considering the diverse polymorphic nature of hAChE, while contemplating any structure-based drug design, the common, nonpathogenic nsSNPs should be considered for the utmost efficacy of drugs.
Osteoblast differentiation is an essential event in the developmental process, which is favoured by the production of extra cellular matrix proteins and various enzymes including discrete ones like acetylcholinesterase (AChE). Despite the fact that AChE facilitates osteoblast differentiation, the significance of its catalytic functions [esterase and aryl acylamidase (AAA) activities] in the process is yet to be ascertained. In this context, SaOS-2 cell line was used in the present study to implicate the catalytic activities of AChE in process of osteoblast differentiation and mineralization. During differentiation, it was found that the activity of both esterase and AAA increased 1.13 and 1.46 folds respectively, signifying the involvement of catalytic activities of AChE in the process. Inhibition of both the catalytic activities of AChE with edrophonium significantly reduced the amount of mineralization by decreasing the alkaline phosphatase (ALP) activity and expression of differentiation-related genes such as RUNX-2, COL1A, ALP, OC, and OP significantly (p < 0.05). Inhibition of esterase activity without altering the AAA activity using gallamine significantly increased the level ALP activity and expression of differentiation-associated genes (p < 0.05), thus favouring mineralization. Therefore, this study concludes and confirms that the AAA activity of AChE is actively involved in the process of osteoblast differentiation and mineralization.
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