MicroRNAs from Holarrhena pubescens stems: Identification by small RNA Sequencing and their Potential Contribution to Human Gene Targets.

Holarrhena pubescens is an effective medicinal plant from the Apocynaceae family, widely distributed over the Indian subcontinent and extensively used by Ayurveda and ethno-medicine systems without apparent side effects. We postulated that miRNAs, endogenous non-coding small RNAs that regulate gene expression at the post-transcriptional level, may, after ingestion into the human body, contribute to the medicinal properties of plants of this species by inducing regulated human gene expression to modulate. However, knowledge is scarce about miRNA in Holarrhena. In addition, to test the hypothesis on the potential pharmacological properties of miRNA, we performed a high-throughput sequencing analysis using the Next Generation Sequencing Illumina platform; 42,755,236 raw reads have been generated from H. pubescens stems from a library of small RNA isolated, identifying 687 known and 50 new miRNAs led. The novel H. pubescens miRNAs were predicted to regulate specific human genes, and subsequent annotations of gene functions suggested a possible role in various biological processes and signaling pathways, such as Wnt, MAPK, PI3K-Akt, and AMPK signaling pathways and endocytosis. The association of these putative targets with many diseases, including cancer, congenital malformations, nervous system disorders, and cystic fibrosis, has been demonstrated. The top hub proteins STAT3, MDM2, GSK3B, NANOG, IGF1, PRKCA, SNAP25, SRSF1, HTT, and SNCA show their interaction with human diseases, including cancer and cystic fibrosis. To our knowledge, this is the first report of uncovering H. pubescens miRNAs based on high-throughput sequencing and bioinformatics analysis. This study has provided new insight into a potential cross-species control of human gene expression. The potential for miRNA transfer should be evaluated as one possible mechanism of action to account for the beneficial properties of this valuable species.

Small RNA sequencing and identification of Andrographis paniculata miRNAs with potential cross­kingdom human gene targets.

Cross-species post-transcriptional regulatory potential of plant derived small non-coding microRNAs (miRNAs) has been well documented by plenteous studies. MicroRNAs are transferred to host cells via oral ingestion wherein they play a decisive role in regulation of host genes; thus, miRNAs have evolved as the nascent bioactive molecules imparting pharmacological values to traditionally used medicinal plants. The present study aims to investigate small RNA profiling in order to uncover the potential regulatory role of miRNAs derived from Andrographis paniculata, one of the most widely used herb by tribal communities for liver disorders and document the pharmacological properties of A. paniculata miRNAs. In this study, high-throughput sequencing method was used to generate raw data, ~ 60 million sequences were generated from A. paniculata leaves. Using computational tools and bioinformatics approach, analyses of 3,480,097 clean reads resulted in identification of 3440 known and 51 putative novel miRNAs regulating 1365 and 192 human genes respectively. Remarkably, the identified plausible novel miRNAs apa-miR-5, apa-miR-1, apa-miR-26, and apa-miR-30 are projected to target significant host genes including CDK6, IKBKB, TRAF3, CHD4, MECP2, and ADIPOQ. Subsequent annotations revealed probable involvement of the target genes in various pathways for instance p38-MAPK, AKT, AMPK, NF-Kß, ERK, WNT signalling, MYD88 dependant cascade, and pathways in cancer. Various diseases such as human papilloma virus infection, Alzheimer's, Non-alcoholic Fatty Liver, Alcoholic liver diseases, HepatoCellular Carcinoma (HCC), and numerous other cancers were predominantly found to be linked with target genes. Our findings postulate novel interpretations regarding modulation of human transcripts by A. paniculata miRNAs and exhibit the regulation of human diseases by plant-derived miRNAs. Though our study elucidates miRNAs as novel therapeutic agents, however, experimental validations for assessment of therapeutic potential of these miRNAs are still warranted.