Circular RNAs: the Emerging Class of Non-coding RNAs and Their Potential Role in Human Neurodegenerative Diseases

Abstract

The exciting world of research with RNAs has to its credit some breakthrough findings that led to newer insights on multiple problems including that of human diseases. After the advent of siRNA, microRNA, and lncRNA, exciting novel molecules called circular RNAs (circRNAs) have been recently described. circRNAs are a class of non-coding RNAs, which are produced by scrambling of exons at the time of splicing. They are primarily produced in the brain region and are naturally present inside the cell. The best known ones so far include a particular type of circRNA namely "circular RNA sponge for miR-7" (ciRS-7 and CDR1as) which is the inhibitor of miR-7 microRNA-known to regulate various diseases like, cancer, neurodegenerative diseases, diabetes, and atherosclerosis. Similarly, another circRNA molecule called circmbl modulates the ratio of linear mRNA by competing with linear muscleblind gene through which it is synthesized. Considering the complex association of these molecules with critical microRNAs and gene families, circRNAs might have important roles in the cause and progression of human diseases. In particular, the multi-factorial nature of neurodegenerative diseases does warrant studies employing novel approaches towards identifying underlying root causes of these ailments. The non-coding RNAs, like circRNAs and microRNAs, could well present a common genetic trigger to multiple factors associated with neurodegenerative diseases. A specific fingerprint of a combination of various marker circRNAs could be explored for early diagnostic purpose as well. Herein, we review the possibility of exploring the role of circRNAs in the context of the central nervous system (CNS) and age-associated neurodegenerative diseases.

Retracted: Circular RNA circFNDC3B protects renal carcinoma by miR‐99a downregulation

“…In recent years, circular noncoding RNA (circRNA) which is originally thought to be genomic noise has been demonstrated to have vital biological efficacies (Kumar, Shamsuzzama, Haque, Baghel, & Nazir, 2017). Numerous studies have demonstrated that circRNAs can play a regulatory part in the translation and binding of miRNAs and so forth (Beermann, Piccoli, Viereck, & Thum, 2016).…”

Rat BodyMap transcriptomes reveal unique circular RNA features across tissue types and developmental stages

“…In addition, aberrant circRNA expression is related to 68 human diseases , including human cancers (Meng et al 2017), neural 69 degenerative diseases (Kumar et al 2017), hematological malignancies (Bonizzato et al 2016), 70 and infectious diseases (Qian et al 2018). However, these conclusions might be preliminary and premature, since the circRNA profiles 82 examined in these studies were derived from relatively small datasets, such as RNA sequencing 83…”

The Role of Circular RNAs in Immune-Related Diseases

“…Both mechanisms work together to promote VEGFB expression, which ultimately mediates the physiological process of neuropathic pain (61) ( Table 1). Moreover, circRNAs are associated with myotonic dystrophy and amyotrophic lateral sclerosis (ALS) (80).…”