In Silico Study of piRNA Interactions with the SARS-CoV-2 Genome

The potential emerging role of piRNA/PIWI complex in virus infection

P-element-induced wimpy testis-interacting RNAs (piRNAs), a class of small noncoding RNAs with about 24-32 nucleotides, often interact with PIWI proteins to form a piRNA/PIWI complex that could influence spermiogenesis, transposon silencing, epigenetic regulation, etc. PIWI proteins have a highly conserved function in a variety of species and are usually expressed in germ cells. However, increasing evidence has revealed the important role of the piRNA/PIWI complex in the occurrence and prognosis of various human diseases and suggests its potential application in the diagnosis and treatment of related diseases, becoming a prominent marker for these human diseases. Recent studies have confirmed that piRNA/PIWI complexes or piRNAs are abnormally expressed in some viral infections, effecting disease progression and viral replication. In this study, we reviewed the association between the piRNA/PIWI complex and several human disease-associated viruses, including human papillomavirus, human immunodeficiency virus, human rhinovirus, severe acute respiratory syndrome coronavirus 2, respiratory syncytial virus, and herpes simplex virus type 1.

Integrative role of small non-coding RNAs in viral immune response: a systematic review

Various viruses cause viral infection, and these viruses have different microscopic sizes, genetic material, and morphological forms. Due to a viral infection, the host body induces defense mechanisms that activate the innate and adaptive immune system. sncRNAs are involved in various biological processes and play an essential role in antiviral response in viruses including ZIKV, HCV, DENV, SARS-CoV, and West Nile virus, and regulate the complex interactions between the viruses and host cells. This review discusses the role of miRNAs, siRNAs, piRNAs, and tiRNAs in antiviral response. Cellular miRNAs bind with virus mRNA and perform their antiviral response in multiple viruses. However, the chemical modifications of miRNA necessary to avoid nuclease attack, which is then involved with intracellular processing, have proven challenging for therapeutic replacement of miRNAs. siRNAs have significant antiviral responses by targeting any gene of interest along the correct nucleotide of targeting mRNA. Due to this ability, siRNAs have valuable characteristics in antiviral response for therapeutic purposes. Additionally, the researchers noted the involvement of piRNAs and tiRNAs in the antiviral response, yet their findings were deemed insignificant.

Interactions of piRNAs with the mRNA of Candidate Genes in Esophageal Squamous Cell Carcinoma

Recently, a database of human piRNAs (piwi-interacting RNAs) was created, which allows the study of the binding of many piRNAs to the mRNAs of genes involved in many diseases, including cancer. In the present work, we identified the piRNAs that can interact with candidate esophageal squamous cell carcinoma (ESCC) genes. The binding of 480 thousand piRNAs with the mRNAs of 66 candidate ESCC genes was studied. Bioinformatic studies found that piRNAs bind only to the mRNAs of nine candidate genes: AURKA, BMP7, GCOM1, ERCC1, MTHFR, SASH1, SIX4, SULT1A1, and TP53. It has been shown that piRNAs can bind to mRNA by overlapping nucleotide sequences in limited 3'UTR and 5'UTR regions called clusters of binding sites (BSs). The existence of clusters of piRNA BSs significantly reduces the proportion of the nucleotide sequences of these sites in the mRNA of target genes. Competition between piRNAs occurs for binding to the mRNA of target genes. Individual piRNAs and groups of piRNAs that have separate BSs and clusters of BSs in the mRNAs of two or more candidate genes have been identified in the mRNAs of these genes. This organization of piRNAs BSs indicates the interdependence of the expression of candidate genes through piRNAs. Significant differences in the ability of genes to interact with piRNAs prevent the side effects of piRNAs on genes with a lack of the ability to bind such piRNAs. Individual piRNAs and sets of piRNAs are proposed and recommended for the diagnosis and therapy of ESCC.

Developmental Biology: Computational and Experimental Approaches

Developmental biology studies ontogenesis, the individual development of an organism from the time of fertilization in sexual reproduction or its expelling from the maternal organism in asexual reproduction to the end of an organism's life, with all phenotypical characters typical of this biological species and supporting the normal course of all biochemical processes and morphogenesis [...].

Endogenous piRNAs Can Interact with the Omicron Variant of the SARS-CoV-2 Genome

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which caused the COVID-19 pandemic, can still infect populations in many countries around the globe. The Omicron strain is the most mutated variant of SARS-CoV-2. The high transmissibility of the strain and its ability to evade immunity necessitate a priority study of its properties in order to quickly create effective means of preventing its spread. The current research aimed to examine the in silico interaction between PIWI-interacting RNAs (piRNAs) and the SARS-CoV-2 genome (gRNA) to identify endogenous piRNAs and propose synthetic piRNAs with strong antiviral activity for drug development. This study used validated bioinformatic approaches regarding the interaction of more than eight million piRNAs with the SARS-CoV-2 genome. The piRNAs’ binding sites (BSs) in the 5′UTR were located with overlapping nucleotide sequences termed clusters of BSs. Several BSs clusters have been found in the nsp3, nsp7, RNA-dependent RNA polymerase, endoRNAse, S surface glycoprotein, ORF7a, and nucleocapsid. Sixteen synthetic piRNAs that interact with gRNA have been proposed with free binding energy ranging from −170 kJ/mol to −175 kJ/mol, which can be used to create drugs that suppress the reproduction of SARS-CoV-2.