[Molecular mechanism of locus coeruleus involved in acupuncture anti-myocardial ischemia based on transcriptome sequencing].

OBJECTIVE: To explore the molecular mechanism of locus coeruleus（LC） involved in electroacupuncture (EA) anti myocardial ischemia. METHODS: Twenty-four SD rats were randomly divided into sham-operation, model, EA and EA +lesion groups, with 6 rats in each group. The acute myocardial ischemia (AMI) model was established by ligation of the left anterior descending branch of coronary artery. EA (2 Hz/15 Hz, 1 mA) was applied to bilateral "Shenmen" (HT7) -"Tongli" (HT5) and the middle-point between HT7 and HT5 for 30 min, once daily for 3 days. For rats of the EA +lesion group, the virus (300 nL) was injected into bilateral LC before EA treatment. Serum aspartate aminotransferase (AST) was detected by ELISA. The gene expression profiles of rat heart were detected by transcriptome sequencing, the differentially expressed genes were screened, and Gene Ontology (GO) functional classification and Kyoto Encyclopedia of genes and genomes (KEGG) metabolic pathway enrichment analysis were performed. RESULTS: Compared with the sham-operation group, serum AST content was significantly increased in the model group (P<0.01). Following the intervention, serum AST was significantly reduced in the EA group (P<0.01), while the serum AST in the EA + lesion group was significantly higher compared with the EA group (P<0.05). Differential expression analysis showed that 1 138 differentially expressed genes were screened out between the model group and the sham-operation group, 1 330 differentially expressed genes between model and EA group, and 804 differentially expressed genes between EA and EA + lesion group. Among them, 218 differential genes were involved in the regulation of EA anti-myocardial ischemia in LC. GO functional classification analysis showed that these differentially expressed genes mainly involved in cell processes, metabolic processes and biological regulation in biological processes. KEGG pathway analysis showed that these differentially expressed genes were enriched in sulfur relay system, thiamine metabolism, glutathione metabolism, C5 branch dicarboxylic acid metabolism, cell adhesion molecules and Th1 and Th2 cell differentiation. CONCLUSION: EA intervention has a positive effect in anti-myocardial ischemia, which may be related to the sulfur relay system, thiamine metabolism, glutathione metabolism, C5 branch dicarboxylic acid metabolism, cell adhesion molecules and Th1 and Th2 cell differentiation involved in LC.

[Identification of potential genes involved in biosynthesis of flavonoid and analysis of biosynthetic pathway in Fagopyrum dibotrys].

In order to enrich the transcriptome data of Fagopyrum dibotrys plants, analyze the genes encoding key enzyme involved in flavonoid biosynthesis pathway, and mine their functional genes, in this study, we performed RNA sequencing analysis for the rhizomes, roots, flowers, leaves and stems of F. dibotrys on the BGISEQ-500 sequencing platform. After de novo assembly of transcripts, a total of 205 619 unigenes were generated and 132 372 unigenes were obtained and annotated into seven public databases, of which, 81 327 unigenes were mapped to the GO database and most of the unigenes were annotated in cellular process, biological regulation, binding and catalytic activity. Besides, 86 922 unigenes were enriched in 136 pathways using KEGG database' and we identified 82 unigenes that encodes key enzymes involved in flavonoid biosynthesis. Comparing rhizome with root, flower, leaf or stem in F. dibotrys, 27 962 co-expressed differentially expressed genes(DEGs) were obtained. Among them, 23 515 DEGs of rhizome tissue-specific were enriched into 132 pathways and 13 unigenes were significantly enriched in biosynthesis of flavone and flavonol. In addition, we also identified 3 427 unigenes encoding 60 transcription factor(TFs) families as well as four unigenes encoding bHLH TFs were enriched in flavonoid biosynthesis. Our results greatly enriched the transcriptome database of plants, provided a reference for the analysis of key enzymes involved in flavonoid biosynthesis in plants, and will facilitate the study of the functions and regulatory mechanisms of key enzymes involved in flavonoid biosynthesis in F. dibotrys at the genetic level.

[Identification of key enzyme genes involved in biosynthesis of steroidal saponins and analysis of biosynthesis pathway in Polygonatum cyrtonema].

Steroidal saponins, which are the characteristic and main active constituents of Polygonatum, exhibit a broad range of pharmacological functions, such as regulating blood sugar, preventing cardiovascular and cerebrovascular diseases and anti-tumor. In this study, we performed RNA sequencing(RNA-Seq) analysis for the flowers, leaves, roots, and rhizomes of Polygonatum cyrtonema using the BGISEQ-500 platform to understand the biosynthesis pathway of steroidal saponins and study their key enzyme genes. The assembly of transcripts for four tissues generated 129 989 unigenes, of which 88 958 were mapped to several public databases for functional annotation, 22 813 unigenes were assigned to 53 subcategories and 64 877 unigenes were annotated to 136 pathways in KEGG database. Furthermore, 502 unigenes involved in the biosynthesis pathway of steroidal saponins were identified, of which 97 unigenes encoding 12 key enzymes. Cycloartenol synthase, the first key enzyme in the pathway of phytosterol biosynthesis, showed conserved catalytic domain and substrate binding domain based on sequence analysis and homology modeling. Differentially expressed genes(DEGs) were identified in rhizomes as compared to other tissues(flowers, leaves or roots).The 2 437 unigenes annotated by KEGG showed rhizome-specific expression, of which 35 unigenes involved in the biosynthesis of steroidal saponins. Our results greatly extend the public transcriptome dataset of Polygonatum and provide valuable information for the identification of candidate genes involved in the biosynthesis of steroidal saponins and other important secondary metabolites.

[Cloning and characterization of chalcone synthase and chalcone isomerase genes in Arisaema heterophyllum].

Chalcone synthase( CHS) and chalcone isomerase( CHI) are key enzymes in the biosynthesis pathway of flavonoids. In this study,unigenes for CHS and CHI were screened from the transcriptome database of Arisaema heterophyllum. The open reading frame( ORFs) of chalcone synthase( Ah CHS) and chalcone isomerase( Ah CHI) were cloned from the plant by RT-PCR. The physicochemical properties,expression and structure characteristics of the encoded proteins Ah CHS and Ah CHI were analyzed. The ORFs of Ah CHS and Ah CHI were 1 176,630 bp in length and encoded 392,209 amino acids,respectively. Ah CHS functioned as a symmetric homodimer. The N-terminal helix of one monomer entwined with the corresponding helix of another monomer. Each CHS monomer consisted of two structural domains. In particular,four conserved residues define the active site. The tertiary structure of Ah CHI revealed a novel open-faced ß-sandwich fold. A large ß-sheet( ß4-ß11) and a layer of α-helices( α1-α7) comprised the core structure. The residues spanning ß4,ß5,α4,and α6 in the three-dimensional structure were conserved among CHIs from different species. Notably,these structural elements formed the active site on the protein surface,and the topology of the active-site cleft defined the stereochemistry of the cyclization reaction. The homology comparison showed that Ah CHS had the highest similarity to the CHS of Anthurium andraeanum,while Ah CHI had the highest similarity to the CHI of Paeonia delavayi. This study provided the basis for the functional study of Ah CHS and Ah CHI and the further study on plant flavonoid biosynthesis pathway.