Characterizing Relevant MicroRNA Editing Sites in Parkinson's Disease.

MicroRNAs (miRNAs) are extensively edited in human brains. However, the functional relevance of the miRNA editome is largely unknown in Parkinson's disease (PD). By analyzing small RNA sequencing profiles of brain tissues of 43 PD patients and 88 normal controls, we found that the editing levels of five A-to-I and two C-to-U editing sites are significantly correlated with the ages of normal controls, which is disrupted in PD patients. We totally identified 362 miRNA editing sites with significantly different editing levels in prefrontal cortices of PD patients (PD-PC) compared to results of normal controls. We experimentally validated that A-to-I edited miR-497-5p, with significantly higher expression levels in PD-PC compared to normal controls, directly represses OPA1 and VAPB. Furthermore, overexpression of A-to-I edited miR-497-5p downregulates OPA1 and VAPB in two cell lines, and inhibits proliferation of glioma cells. These results suggest that the hyperediting of miR-497-5p in PD contributes to enhanced progressive neurodegeneration of PD patients. Our results provide new insights into the mechanistic understanding, novel diagnostics, and therapeutic clues of PD.

Gut microbiota and metabolites of α-synuclein transgenic monkey models with early stage of Parkinson's disease.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease. However, it is unclear whether microbiota and metabolites have demonstrated changes at early PD due to the difficulties in diagnosis and identification of early PD in clinical practice. In a previous study, we generated A53T transgenic monkeys with early Parkinson's symptoms, including anxiety and cognitive impairment. Here we analyzed the gut microbiota by metagenomic sequencing and metabolites by targeted gas chromatography. The gut microbiota analysis showed that the A53T monkeys have higher degree of diversity in gut microbiota with significantly elevated Sybergistetes, Akkermansia, and Eggerthella lenta compared with control monkeys. Prevotella significantly decreased in A53T transgenic monkeys. Glyceric acid, L-Aspartic acid, and p-Hydroxyphenylacetic acid were significantly elevated, whereas Myristic acid and 3-Methylindole were significantly decreased in A53T monkeys. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (KO0131) and the oxidative phosphorylation reaction (KO2147) were significantly increased in metabolic pathways of A53T monkeys. Our study suggested that the transgenic A53T and α-syn aggregation may affect the intestine microbiota and metabolites of rhesus monkeys, and the identified five compositional different metabolites that are mainly associated with mitochondrial dysfunction may be related to the pathogenesis of PD.

A developmental landscape of 3D-cultured human pre-gastrulation embryos.

Our understanding of how human embryos develop before gastrulation, including spatial self-organization and cell type ontogeny, remains limited by available two-dimensional technological platforms1,2 that do not recapitulate the in vivo conditions3-5. Here we report a three-dimensional (3D) blastocyst-culture system that enables human blastocyst development up to the primitive streak anlage stage. These 3D embryos mimic developmental landmarks and 3D architectures in vivo, including the embryonic disc, amnion, basement membrane, primary and primate unique secondary yolk sac, formation of anterior-posterior polarity and primitive streak anlage. Using single-cell transcriptome profiling, we delineate ontology and regulatory networks that underlie the segregation of epiblast, primitive endoderm and trophoblast. Compared with epiblasts, the amniotic epithelium shows unique and characteristic phenotypes. After implantation, specific pathways and transcription factors trigger the differentiation of cytotrophoblasts, extravillous cytotrophoblasts and syncytiotrophoblasts. Epiblasts undergo a transition to pluripotency upon implantation, and the transcriptome of these cells is maintained until the generation of the primitive streak anlage. These developmental processes are driven by different pluripotency factors. Together, findings from our 3D-culture approach help to determine the molecular and morphogenetic developmental landscape that occurs during human embryogenesis.

Identifying microRNAs and Their Editing Sites in Macaca mulatta.

MicroRNAs (miRNAs) are small non-coding RNAs that are critical in post-transcriptional regulation. Macaca mulatta is an important nonhuman primate that is often used in basic and translational researches. However, the annotation of miRNAs in Macaca mulatta is far from complete, and there are no reports of miRNA editing events in Macaca mulatta, although editing may affect the biogenesis or functions of the miRNAs. To improve miRNA annotation and to reveal editing events of miRNAs in Macaca mulatta, we generated 12 small RNA profiles from eight tissues and performed comprehensive analysis of these profiles. We identified 479 conserved pre-miRNAs that have not been reported in Macaca mulatta and 17 species specific miRNAs. Furthermore, we identified 3386 editing sites with significant editing levels from 471 pre-miRNAs after analyzing the 12 self-generated and 58 additional published sRNA-seq profiles from 17 different types of organs or tissues. In addition to 16 conserved A-to-I editing sites, we identified five conserved C-to-U editing sites in miRNAs of Macaca mulatta and Homo sapiens. We also identified 11 SNPs in the miRNAs of Macaca mulatta. The analysis of the potential targets of 69 miRNAs with editing or mutation events in their seed regions suggest that these editing or mutation events severely changed their targets and their potential functions. These results significantly increase our understanding of miRNAs and their mutation/editing events in Macaca mulatta.

Analysis of microRNAs, phased small interfering RNAs and their potential targets in Rosarugosa Thunb.

BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs that play important roles by regulating other genes. Rosa rugosa Thunb. is an important ornamental and edible plant, yet there are only a few studies on the miRNAs and their functions in R. rugosa. RESULTS: We sequenced 10 samll RNA profiles from the roots, petals, pollens, stamens, and leaves and 4 RNA-seq profiles in leaves and petals to analysis miRNA, phasiRNAs and mRNAs in R. rugosa. In addition, we acquired a degradome sequencing profile from leaf of R. rugosa to identify miRNA and phasiRNA targets using the SeqTar algorithm. We have identified 321 conserved miRNA homologs including primary transcripts for 25 conserved miRNAs, and 22 novel miRNAs. We identified 592 putative targets of the conserved miRNAs or tasiRNAs that showed significant accumulations of degradome reads. We found differential expression patterns of conserved miRNAs in five different tissues of R. rugosa. We identified three hundred and thirty nine 21 nucleotide (nt) PHAS loci, and forty nine 24 nt PHAS loci, respectively. Our results suggest that miR482 triggers generations of phasiRNAs by targeting nucleotide-binding, leucine-rich repeat (NB-LRR) disease resistance genes in R. rugosa. Our results also suggest that the deregulated genes in leaves and petals are significantly enriched in GO terms and KEGG pathways related to metabolic processes and photosynthesis. CONCLUSIONS: These results significantly enhanced our knowledge of the miRNAs and phasiRNAs, as well as their potential functions, in R. rugosa.

Genome-wide identification and comprehensive analysis of microRNAs and phased small interfering RNAs in watermelon.

BACKGROUND: MicroRNAs (miRNAs) are a class of endogenous small non-coding RNAs involved in the post-transcriptional gene regulation and play a critical role in plant growth, development and stress responses. Watermelon (Citrullus lanatus L.) is one of the important agricultural crops worldwide. However, the watermelon miRNAs and phasiRNAs and their functions are not well explored. RESULTS: Here we carried out computational and experimental analysis of miRNAs and phased small interfering RNAs (phasiRNAs) in watermelon by analyzing 14 small RNA profiles from roots, leaves, androecium, petals, and fruits, and one published small RNA profile of mixed tissues. To identify the targets of miRNAs and phasiRNAs, we generated a degradome profile for watermelon leaf which is analyzed using the SeqTar algorithm. We identified 97 conserved pre-miRNAs, of which 58 have not been reported previously and 348 conserved mature miRNAs without precursors. We also found 9 novel pre-miRNAs encoding 18 mature miRNAs. One hundred and one 21 nucleotide (nt) PHAS loci, and two hundred and forty one 24 nt PHAS loci were also identified. We identified 127 conserved targets of the conserved miRNAs and TAS3-derived tasiRNAs by analyzing a degradome profile of watermelon leaf. CONCLUSIONS: The presented results provide a comprehensive view of small regulatory RNAs and their targets in watermelon.

Phased secondary small interfering RNAs in Panaxnotoginseng.

BACKGROUND: Recent results demonstrated that either non-coding or coding genes generate phased secondary small interfering RNAs (phasiRNAs) guided by specific miRNAs. Till now, there is no studies for phasiRNAs in Panax notoginseng (Burk.) F.H. Chen (P. notoginseng), an important traditional Chinese herbal medicinal plant species. METHODS: Here we performed a genome-wide discovery of phasiRNAs and its host PHAS loci in P. notoginseng by analyzing small RNA sequencing profiles. Degradome sequencing profile was used to identify the trigger miRNAs of these phasiRNAs and potential targets of phasiRNAs. We also used RLM 5'-RACE to validate some of the identified phasiRNA targets. RESULTS: After analyzing 24 small RNA sequencing profiles of P. notoginseng, 204 and 90 PHAS loci that encoded 21 and 24 nucleotide (nt) phasiRNAs, respectively, were identified. Furthermore, we found that phasiRNAs produced from some pentatricopeptide repeat-contain (PPR) genes target another layer of PPR genes as validated by both the degradome sequencing profile and RLM 5'-RACE analysis. We also found that miR171 with 21 nt triggers the generations of 21 nt phasiRNAs from its conserved targets. CONCLUSIONS: We validated that some phasiRNAs generated from PPRs and TASL genes are functional by targeting other PPRs in trans. These results provide the first set of PHAS loci and phasiRNAs in P. notoginseng, and enhance our understanding of PHAS in plants.

Genotype- and tissue-specific miRNA profiles and their targets in three alfalfa (Medicago sativa L) genotypes.

BACKGROUND: Alfalfa (Medicago sativa L.) is a forage legume with significant agricultural value worldwide. MicroRNAs (miRNAs) are key components of post-transcriptional gene regulation and essentially regulate many aspects of plant growth and development. Although miRNAs were reported in alfalfa, their expression profiles in different tissues and the discovery of novel miRNAs as well as their targets have not been described in this plant species. RESULTS: To identify tissue-specific miRNA profiles in whole plants, shoots and roots of three different alfalfa genotypes (Altet-4, NECS-141and NF08ALF06) were used. Small RNA libraries were generated and sequenced using a high-throughput sequencing platform. Analysis of these libraries enabled identification of100 miRNA families; 21 of them belong to the highly conserved families while the remaining 79 families are conserved at the minimum between M. sativa and the model legume and close relative, M. truncatula. The profiles of the six abundantly expressed miRNA families (miR156, miR159, miR166, miR319, miR396 and miR398) were relatively similar between the whole plants, roots and shoots of these three alfalfa genotypes. In contrast, robust differences between shoots and roots for miR160 and miR408 levels were evident, and their expression was more abundant in the shoots. Additionally, 17 novel miRNAs were identified and the relative abundance of some of these differed between tissue types. Further, the generation and analysis of degradome libraries from the three alfalfa genotypes enabled confirmation of 69 genes as targets for 31 miRNA families in alfalfa. CONCLUSIONS: The miRNA profiles revealed both similarities and differences in the expression profiles between tissues within a genotype as well as between the genotypes. Among the highly conserved miRNA families, miR166 was the most abundantly expressed in almost all tissues from the three genotypes. The identification of conserved and novel miRNAs as well as their targets in different tissues of multiple genotypes increased our understanding of miRNA-mediated gene regulation in alfalfa and could provide valuable insights for practical research and plant improvement applications in alfalfa and related legume species.