[Role and mechanism of IL-6/STAT3/Th17 signaling pathway in the intervention of forsythia in acute lung injury of septic rats]

Objective: To investigate the mechanism of interleukin-6 (IL-6) /signal transducers and activators of transcriptional 3 (STAT3) /helper T cell 17 (Th17) signaling pathway in lung injury of rats with sepsis intervened by forsythia, with a view to provide experimental basis for the role and mechanism of forsythia in the treatment of sepsis. Methods: In July 2021, 30 healthy Wistar male rats were selected and randomly divided into sham operation group, model group and treatment group, with 10 rats in each group. The rat model of sepsis was established by cecal ligation and puncture. 2 h after recovery, the rats were given traditional Chinese medicine forsythia orally, twice a day at an interval of 12 h. The wet/dry mass ratio (W/D) of lung tissue was detected 24 h after surgery. The morphological changes of lung tissue were detected by HE staining. Flow cytometry was used to detect Th17 population in peripheral blood. The expression levels of IL-6 and interleukin-17A (IL-17A) in serum were determined by enzyme-linked immunosorbent assay. The mRNA expression levels of IL-17A and IL-6 in lung tissues were detected by reverse transcription-polymerase chain reaction. The expression levels of STAT3 and IL-17A in lung tissue were determined by Western blotting. Results: Compared with model group, the W/D of lung tissue in treatment group was decreased, and the difference was statistically significant (P<0.05). HE staining of lung tissue showed that compared with the model group, the degree of lung lesion and injury was reduced in the treatment group. Compared with sham operation group, the proportion of Th17 cells in CD4 lymphocytes in peripheral blood of rats in model group was significantly increased (P<0.05). Compared with model group, the proportion of Th17 cells in CD4 lymphocytes in peripheral blood of rats in treatment group was significantly decreased (P<0.05). Compared with sham operation group, peripheral blood serum IL-6 and IL-17 of rats in model group were significantly increased (P<0.05). Compared with model group, IL-6 and IL-17 in peripheral blood serum of rats in treatment group were decreased (P<0.05). Compared with sham operation group, the expressions of IL-17A and IL-6 mRNA in lung tissue of model group were significantly increased (P<0.05). Compared with model group, the expressions of IL-17A and IL-6 mRNA in lung tissue of rats in treatment group were significantly decreased (P<0.05). Compared with sham operation group, the protein expressions of STAT3 and IL-17A in lung tissue in model group were significantly increased (P<0.05). Compared with model group, the pritein expressions of STAT3 and IL-17A in lung tissue in treatment group were significantly decreased (P<0.05) . Conclusion: Forsythia plays a role in alleviating lung injury by down-regulating the expressions of the signaling pathway IL-6/STAT3/Th17, which providing a new target for the treatment of sepsis induced lung injury.

FsHemF is involved in the formation of yellow Forsythia leaves by regulating chlorophyll synthesis in response to light intensity

The leaves of Forsythia koreana 'Suwon Gold' are yellow under natural light condition and can revert to green when the light intensity is reduced. To understand the molecular mechanism of leaf color changes in response to light intensity, we compared the chlorophyll content and precursor content between yellow- and green-leaf Forsythia under shade and light-recovery conditions. We identified the conversion of coproporphyrin III (Coprogen III) to protoporphyrin IX (Proto IX) as the primary rate-limiting step of chlorophyll biosynthesis in yellow-leaf Forsythia. Further analysis of the activity of the enzymes that catalyze this step and the expression pattern of the chlorophyll biosynthesis-related genes under different light intensities revealed that the negatively regulated expression of FsHemF by light intensity was the major cause affecting the leaf color change in response to light intensity in yellow-leaf Forsythia. To further understand the cause of differential expression pattern of FsHemF in yellow- and green-leaf lines, we compared the coding sequence and promoter sequence of FsHemF between yellow- and green-leaf Forsythia. We found that one G-box light-responsive cis-element was absent in the promoter region of green-leaf lines. To investigate the functional role of FsHemF, we performed virus-induced gene silencing (VIGS) of FsHemF in green-leaf Forsythia, which leads to yellowing leaf veins, decreased chlorophyll b content, and inhibition of chlorophyll biosynthesis. The results will assist in elucidating the mechanism of yellow-leaf Forsythia in response to light intensity.

Comparative transcriptome analysis identified ChlH and POLGAMMA2 in regulating yellow-leaf coloration in Forsythia

Leaf color is one of the most important features for plants used for landscape and ornamental purposes. However, the regulatory mechanism of yellow leaf coloration still remains elusive in many plant species. To understand the complex genetic mechanism of yellow-leaf Forsythia, we first compared the pigment content and leaf anatomical structure of yellow-leaf and green-leaf accessions derived from a hybrid population. The physiological and cytological analyses demonstrated that yellow-leaf progenies were chlorophyll deficient with defected chloroplast structure. With comparative transcriptome analysis, we identified a number of candidate genes differentially expressed between yellow-leaf and green-leaf Forsythia plants. Among these genes, we further screened out two candidates, ChlH (magnesium chelatase Subunit H) and POLGAMMA2 (POLYMERASE GAMMA 2), with consistent relative-expression pattern between different colored plants. To verify the gene function, we performed virus-induced gene silencing assays and observed yellow-leaf phenotype with total chlorophyll content reduced by approximately 66 and 83% in ChlH-silenced and POLGAMMA2-silenced plants, respectively. We also observed defected chloroplast structure in both ChlH-silenced and POLGAMMA2-silenced Forsythia. Transient over-expression of ChlH and POLGAMMA2 led to increased chlorophyll content and restored thylakoid architecture in yellow-leaf Forsythia. With transcriptome sequencing, we detected a number of genes related to chlorophyll biosynthesis and chloroplast development that were responsive to the silencing of ChlH and POLGAMMA2. To summarize, ChlH and POLGAMMA2 are two key genes that possibly related to yellow-leaf coloration in Forsythia through modulating chlorophyll synthesis and chloroplast ultrastructure. Our study provided insights into the molecular aspects of yellow-leaf Forsythia and expanded the knowledge of foliage color regulation in woody ornamental plants.

Network-based pharmacology to predict the mechanism of Ginger and Forsythia combined treatment of viral pneumonia

BACKGROUND

Viral pneumonia (VP) is a common inflammatory disease caused by a virus in the upper respiratory tract. However, current treatment options for pneumonia are limited because of the strong infectivity and lack of research.

METHOD

Based on various databases, the mechanisms of Ginger and Forsythia were predicted by network pharmacology. The possible active ingredients of Ginger and Forsythia were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and screened by pharmacokinetic parameters. Their possible targets were predicted by the TCMSP database. The VP-related targets were collected from the GeneCards and OMIM databases. The compound-target-disease network was visualized by Cytoscape 3.7.1. In addition, the protein functional annotation and identification of signalling pathways of possible targets were performed with Gene Ontology (GO) and KEGG enrichment analysis. Molecular docking was finally employed for in silico simulation matching between representative Ginger and Forsythia compounds and their core genes.

RESULTS

Twenty-eight active ingredients of Ginger and Forsythia were found and 30 common targets for the combined treatment of VP were obtained. The enrichment analysis of GO functions and KEGG pathways included 186 GO function entries and 56 KEGG pathways. Molecular docking showed that the main ingredients can closely bind three targets (CASP3, JUN, and ESR1). Thus, Ginger and Forsythia play significant roles in the prevention and treatment of VP, and this study showed their mechanism was "multicomponent, multitarget, and multipathway" for the prevention and treatment of VP.

CONCLUSION

We successfully predicted the active components and targets of Ginger and Forsythia for prevention and treatment of VP. This may systematically clarify its mechanism of action and provide a direction for future research.

Tissue-Specific Accumulation and Isomerization of Valuable Phenylethanoid Glycosides from Plantago and Forsythia Plants

A comparative phytochemical study on the phenylethanoid glycoside (PhEG) composition of the underground organs of three Plantago species (P. lanceolata, P. major, and P. media) and that of the fruit wall and seed parts of Forsythia suspensa and F. europaea fruits was performed. The leaves of these Forsythia species and six cultivars of the hybrid F. × intermedia were also analyzed, demonstrating the tissue-specific accumulation and decomposition of PhEGs. Our analyses confirmed the significance of selected tissues as new and abundant sources of these valuable natural compounds. The optimized heat treatment of tissues containing high amounts of the PhEG plantamajoside (PM) or forsythoside A (FA), which was performed in distilled water, resulted in their characteristic isomerizations. In addition to PM and FA, high amounts of the isomerization products could also be isolated after heat treatment. The isomerization mechanisms were elucidated by molecular modeling, and the structures of PhEGs were identified by nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry (HR-MS) techniques, also confirming the possibility of discriminating regioisomeric PhEGs by tandem MS. The PhEGs showed no cytostatic activity in non-human primate Vero E6 cells, supporting their safe use as natural medicines and allowing their antiviral potency to be tested.

The embryological insight into the relationship between Forsythia and Abeliophyllum (Forsythieae, Oleaceae)

Forsythia saxatilis, a Korean native Forsythia, is recognized as an endangered species in the Korean Red List. We carried out a comprehensive embryological investigation, including a study of the pericarp development, of F. saxatilis and compared it with previously acquired information on the family Oleaceae and also with Abeliophyllum distichum, a close relative of Forsythia. Our results revealed that several embryological features of Forsythia are exclusively comparable with the family Oleaceae, particularly in relation to A. distichum. Despite the differences in fruit types and pericarp ontogeny, Forsythia shares some unique embryological features with Abeliophyllum, for instance the basic type of anther wall development, formation of the nucellar cap, a long micropyle, formation of the obturator and hypostase, and the crushed endotesta. Furthermore, the loculicidal capsule of Forsythia seems to be primitive within the tribe Forsythieae and samara of Abeliophyllum might be evolved from it. In conclusion, a considerable number of synapomorphies of embryological characters supports recent molecular reports and provide additional embryological evidence for the sister-group relationship of Forsythia and Abeliophyllum.

Selection and validation of appropriate reference genes for gene expression studies in Forsythia

The qRT-PCR method has been widely used to detect gene expression level in plants, helping to understand the molecular mechanisms. However, there are few researches which focus on the selection of the internal reference genes in Forsythia. To select the appropriate reference genes of Forsythia aimed at qRT-PCR normalization, twelve candidate reference genes were selected from our transcriptome data. Their expression was assessed by RT-PCR analysis in 47 Forsythia samples, including 12 species cultivars, different organs and tissues. GeNorm, NormFinder, and BestKeeper software were used to select the appropriate reference genes, AG and PSY were used to verify the accuracy of the outcome. The results showed that UKN1 was a stable reference gene in leaves of twelve Forsythia germplasms and in different developmental stages of fruits. MTP, ABCT + MTP, and ABCT + MTP + TIP were stable reference genes in different organs. ACT and SDH were stable reference genes in different flower tissues and different developmental stages of the flower buds. When Forsythia plants were stressed with PEG or ABA, SDH + UKN1 + G6PD was the stable reference gene group for qRT-PCR. The results provided the basis for investigating the physiological and biochemical processes of Forsythia related to medicinal and ornamental properties, and drought-resistance in the level of gene expression.

Molecular Phylogeny and Dating of Forsythieae (Oleaceae) Provide Insight into the Miocene History of Eurasian Temperate Shrubs

Tribe Forsythieae (Oleaceae), containing two genera (Abeliophyllum and Forsythia) and 13 species, is economically important plants used as ornamentals and in traditional medicine. This tribe species occur primarily in mountainous regions of Eurasia with the highest species diversity in East Asia. Here, we examine 11 complete chloroplast genome and nuclear cycloidea2 (cyc2) DNA sequences of 10 Forsythia species and Abeliophyllum distichum using Illumina platform to provide the phylogeny and biogeographic history of the tribe. The chloroplast genomes of the 11 Forsythieae species are highly conserved, except for a deletion of about 400 bp in the accD-psaI region detected only in Abeliophyllum. Within Forsythieae species, analysis of repetitive sequences revealed a total of 51 repeats comprising 26 forward repeats, 22 palindromic repeats, and 3 reverse repeats. Of those, 19 repeats were common and 32 were unique to one or more Forsythieae species. Our phylogenetic analyses supported the monophyly of Forsythia and its sister group is Abeliophyllum using the concatenated dataset of 78 chloroplast genes. Within Forsythia, Forsythia likiangensis and F. giraldiana were basal lineages followed by F. europaea; the three species are characterized by minutely serrate or entire leaf margins. The remaining species, which are distributed in East Asia, formed two major clades. One clade included F. ovata, F. velutina, and F. japonica; they are morphologically supported by broadly ovate leaves. Another clade of F. suspensa, F. saxatilis, F. viridissima, and F. koreana characterized by lanceolate leaves (except F. suspensa which have broad ovate leaves). Although cyc2 phylogeny is largely congruent to chloroplast genome phylogeny, we find the discordance between two phylogenies in the position of F. ovata suggesting that introgression of the chloroplast genome from one species into the nuclear background of another by interspecific hybridization in East Asian Forsythia species. Molecular dating and biogeographic reconstructions suggest an origin of the Forsythieae species in East China in the Miocene. Distribution patterns in Forsythia indicated that the species were radially differentiated from East China, and the speciation of the European F. europaea was the result of both vicariance and dispersal in the late Miocene to Pliocene.