Exploring the potential targets of the Abrus cantoniensis Hance in the treatment of hepatitis E based on network pharmacology.

Hepatitis E is a disease of public health significance caused by the cross-species transmission of zoonotic hepatitis E virus (HEV) infection. There are no specific drugs. In this study, network pharmacology was used to reveal the mechanism of treatment of the active constituents of the Abrus cantoniensis Hance on hepatitis E. Based on the previously published representative components of A. cantoniensis Hance, we were screened the active components with OB ≥ 20% and DL ≥ 0.1 in A. cantoniensis Hance based on the TCMSP, predicted the target online through Swiss target prediction, and integrated the hepatitis E target in the GeneCards and DisGenet databases. Then, the core target was screened and the GO and KEGG enrichment and the network of the drug-active-ingredient-disease-pathway-target analysis were performed by the Cytoscape software. There were 11,046 hepatitis E targets, including PI3K-AKt, SRC, MAPK, PTPN11, EGFR, STAT1 and so on. The core ingredients include Oleanolic acid, Butin, ß-sitosterol, Soyasapogenol E, 5,7-dihydroxy-2-methyl-8-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-4-one, Stigmasterol, Emodin, Physcion, and Enoxolone. A total of 1,410 GO enrichment results of core targets, including 1,246 biological process, 51 cell composition and 113 molecular function results. KEGG pathway was enriched in 150 related pathways, suggesting that A. cantoniensis Hance acts on cancer signaling pathway, endocrine resistance pathway, PI3K-AKt signaling pathway, MAPK, TNF and other signaling pathway. Through key components such as Oleanolic acid, Butin, ß-sitosterol, Stigmasterol, and Enoxolone and other components interferes with AKT1, IL-6 and TNF, and regulates pathway in cancer, PI3K-AKt signaling pathway and MAPK pathway to play a therapeutic role in hepatitis E.

HpaP divergently regulates the expression of hrp genes in Xanthomonas oryzae pathovars oryzae and oryzicola.

The bacterial pathogens Xanthomonas oryzae pathovars oryzae (Xoo) and oryzicola (Xoc) cause leaf blight and leaf streak diseases on rice, respectively. Pathogenesis is largely defined by the virulence genes harboured in the pathogen genome. Recently, we demonstrated that the protein HpaP of the crucifer pathogen Xanthomonas campestris pv. campestris is an enzyme with both ATPase and phosphatase activities, and is involved in regulating the synthesis of virulence factors and the induction of the hypersensitive response (HR). In this study, we investigated the role of HpaP homologues in Xoo and Xoc. We showed that HpaP is required for full virulence of Xoo and Xoc. Deletion of hpaP in Xoo and Xoc led to a reduction in virulence and alteration in the production of virulence factors, including extracellular polysaccharide and cell motility. Comparative transcriptomics and reverse transcription-quantitative PCR assays revealed that in XVM2 medium, a mimic medium of the plant environment, the expression levels of hrp genes (for HR and pathogenicity) were enhanced in the Xoo hpaP deletion mutant compared to the wild type. By contrast, in the same growth conditions, hrp gene expression was decreased in the Xoc hpaP deletion mutant compared to the wild type. However, an opposite expression pattern was observed when the pathogens grew in planta, where the expression of hrp genes was reduced in the Xoo hpaP mutant but increased in the Xoc hpaP mutant. These findings indicate that HpaP plays a divergent role in Xoo and Xoc, which may lead to the different infection strategies employed by these two pathogens.

HpaP, a novel regulatory protein with ATPase and phosphatase activity, contributes to full virulence in Xanthomonas campestris pv. campestris.

The ability of the bacterial phytopathogen Xanthomonas campestris pv. campestris (Xcc) to cause disease is dependent on the type III secretion system (T3SS). Proteins of the Xcc T3SS are encoded by hrp (hypersensitive response and pathogenicity) genes and whose expression is mainly controlled by the regulators HrpG and HrpX. Here, we describe the identification and characterization of a previously unknown regulatory protein (named HpaP), which plays important role in hrp gene expression and virulence in Xcc. Clean deletion of hpaP demonstrated reduced virulence and HR (hypersensitive response) induction of Xcc and alterations in cell motility and stress tolerance. Global transcriptome analyses revealed that most hrp genes were down regulated in the hpaP mutant, suggesting HpaP positively regulates hrp genes. GUS activity assays implied that HpaP regulates the expression of hrp genes via controlling the expression of hrpX. Biochemical analyses revealed that HpaP protein had both ATPase and phosphatase activity. While further site-directed mutagenesis of conserved residues in the PTP loop (a protein tyrosine phosphatase signature) of HpaP resulted in the loss of both phosphatase activity and regulatory activity in virulence and HR. Taken together, the findings identify a new regulatory protein that controls hrp gene expression and virulence in Xcc.