The fatty acid 2-hydroxylase CsSCS7 is a key hyphal growth factor and potential control target in Colletotrichum siamense.

SCS7 is a fatty acid 2-hydroxylase required for the synthesis of inositol phosphorylceramide but is not essential for normal growth in Saccharomyces cerevisiae. Here, we demonstrate that the Colletotrichum siamense SCS7 homolog CsSCS7 plays a key role in hyphal growth. The CsSCS7 deletion mutant showed strong hyphal growth inhibition, small conidia, and marginally reduced sporulation and also resulted in a sharp reduction in the full virulence and increasing the fungicide sensitivity. The three protein domains (a cytochrome b5 domain, a transmembrane domain, and a hydroxylase domain) are important to CsSCS7 protein function in hyphal growth. The fatty acid assay results revealed that the CsSCS7 gene is important for balancing the contents of multiple mid-long- and short-chain fatty acids. Additionally, the retarded growth and virulence of C. siamense ΔCsSCS7 can be recovered partly by the reintroduction of homologous sequences from Magnaporthe oryzae and Fusarium graminearum but not SCS7 of S. cerevisiae. In addition, the spraying of C. siamense with naked CsSCS7-double-stranded RNA (dsRNAs), which leads to RNAi, increases the inhibition of hyphal growth and slightly decreases disease lesions. Then, we used nano material Mg-Al-layered double hydroxide as carriers to deliver dsRNA, which significantly enhanced the control effect of dsRNA, and the lesion area was obviously reduced. These data indicated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.IMPORTANCECsSCS7, which is homologous to yeast fatty acid 2-hydroxylase SCS7, was confirmed to play a key role in the hyphal growth of Colletotrichum siamense and affect its virulence. The CsSCS7 gene is involved in the synthesis and metabolism of fatty acids. Homologs from the filamentous fungi Magnaporthe oryzae and Fusarium graminearum can recover the retarded growth and virulence of C. siamense ΔCsSCS7. The spraying of double-stranded RNAs targeting CsSCS7 can inhibit hyphal growth and reduce the disease lesion area to some extent. After using nano material Mg-Al layered double hydroxide as carrier, the inhibition rates were significantly increased. We demonstrated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.

The Plasma Membrane H+ ATPase CsPMA2 Regulates Lipid Droplet Formation, Appressorial Development and Virulence in Colletotrichum siamense.

Plasma membrane H+-ATPases (PMAs) play an important role in the pathogenicity of pathogenic fungi. Lipid droplets are important storage sites for neutral lipids in fungal conidia and hyphae and can be used by plant pathogenic fungi for infection. However, the relationship between plasma membrane H+-ATPase, lipid droplets and virulence remains unclear. Here, we characterized a plasma membrane H+-ATPase, CsPMA2, that plays a key role in lipid droplet formation, appresorial development and virulence in C. siamense. Deletion of CsPMA2 impaired C. siamense conidial size, conidial germination, appressorial development and virulence but did not affect hyphal growth. ΔCsPMA2 increased the sensitivity of C. siamense to phytic acid and oxalic acid. CsPMA2 was localized to lipids on the plasma membrane and intracellular membrane. Deletion of CsPMA2 significantly inhibited the accumulation of lipid droplets and significantly affected the contents of some species of lipids, including 12 species with decreased lipid contents and 3 species with increased lipid contents. Furthermore, low pH can inhibit CsPMA2 expression and lipid droplet accumulation. Overall, our data revealed that the plasma membrane H+-ATPase CsPMA2 is involved in the regulation of lipid droplet formation and affects appressorial development and virulence in C. siamense.

p120-catenin promotes innate antiviral immunity through stabilizing TBK1-IRF3 complex.

TBK1-IRF3 complex plays vital roles in antiviral immune responses, its regulatory mechanisms are currently incompletely understood. p120-catenin (p120), an armadillo-repeat protein, mainly regulates the stability of classical cadherins and the development of epithelial-to-mesenchymal transitions (EMTs). Here we report that p120 is a positive regulator of type I IFN production. Ectopic expression of p120 enhanced Vesicular stomatitis virus and Sendai-virus-induced type I IFN production, whereas knockdown of p120 expression suppressed type I IFN production. Mechanistically, p120 promoted phosphorylation of IRF3 via stabilizing the TBK1-IRF3 complex. Consistently, p120 knock down mice are more susceptible to VSV infection as indicated by higher tissue viral titers, less IFN-I production and greater infiltration of immune cells. This study reveals p120 as an important positive regulator in innate immunity and identifies that p120 facilitates host antiviral response through stabilizing TBK1-IRF3 complex.

Diverse roles of UBE2T in cancer (Review).

As a leading cause of mortalities worldwide, cancer results from accumulation of both genetic and epigenetic alterations. Disruption of epigenetic regulation in cancer, particularly aberrant ubiquitination, has drawn increasing interest in recent years. The present study aimed to review the roles of ubiquitin­conjugating enzyme E2 T (UBE2T) and its associated pathways in the pathogenesis of pan­cancer, and the development of small­molecule modulators to regulate ubiquitination for treatment strategies. The current study comprehensively investigated the expression landscape and functional significance of UBE2T, as well as its correlation with cancer cell sensitivity to chemotherapy/radiotherapy. Multiple levels of evidence suggested that aberrant UBE2T played important roles in pan­cancer. Information was collected from 16 clinical trials on ubiquitin enzymes, and it was found that these molecules had an important role in the ubiquitin­proteasome system. Further studies are necessary to explore their feasibility and effectiveness as diagnostic and prognostic biomarkers, or as up/down­stream and therapeutic targets for cancer treatment.

NE-activated ß2-AR/ß-arrestin 2/Src pathway mediates duodenal hyperpermeability induced by water-immersion restraint stress.

Stress causes a rapid spike in norepinephrine (NE) levels, leading to gastrointestinal dysfunction. NE reduces the expression of tight junctions (TJs) and aggravates intestinal mucosal damage, but the regulatory mechanism is still unclear. The present study aimed to investigate the molecular mechanisms underlying the regulation of stress-associated duodenal hyperpermeability by NE. Fluorescein isothiocyanate-dextran permeability, transepithelial resistance, immunofluorescence, Western blot, and high-performance liquid chromatography analysis were used in water-immersion restraint stress (WIRS) rats in this study. The results indicate that the duodenal permeability, degradation of TJs, mucosal NE, and ß2-adrenergic receptor (ß2-AR) increased in WIRS rats. The duodenal intracellular cyclic adenosine monophosphate levels were decreased, whereas the expression of ß-arrestin 2 negatively regulates G protein-coupled receptors signaling, was significantly increased. Src recruitment was mediated by ß-arrestin; thus, the levels of Src kinase activation were enhanced in WIRS rats. NE depletion, ß2-AR, or ß-arrestin 2 blockade significantly decreased mucosal permeability and increased TJs expression, suggesting improved mucosal barrier function. Moreover, NE induced an increased duodenal permeability of normal rats with activated ß-arrestin 2/Src signaling, which was significantly inhibited by ß2-AR blockade. The present findings demonstrate that the enhanced NE induced an increased duodenal permeability in WIRS rats through the activated ß2-AR/ß-arrestin 2/Src pathway. This study provides novel insight into the molecular mechanism underlying the regulation of NE on the duodenal mucosal barrier and a new target for treating duodenal ulcers induced by stress.

A designed antimicrobial peptide with potential ability against methicillin resistant Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is a Gram-positive pathogenic bacterium, which persistently colonizes the anterior nares of approximately 20-30% of the healthy adult population, and up to 60% is intermittently colonized. With the misuse and overuse of antibiotics, large-scale drug-resistant bacteria, including methicillin-resistant S. aureus (MRSA), have been appeared. MRSA is among the most prevalent pathogens causing community-associated infections. Once out of control, the number of deaths caused by antimicrobial resistance may exceed 10 million annually by 2050. Antimicrobial peptides (AMPs) are regarded as the best solution, for they are not easy to develop drug resistance. Based on our previous research, here we designed a new antimicrobial peptide named GW18, which showed excellent antimicrobial activity against S. aureus, even MRSA, with the hemolysis less than 5%, no cytotoxicity, and no acute toxicity. Notably, administration of GW18 significantly decreased S. aureus infection in mouse model. These findings identify GW18 as the ideal candidate against S. aureus infection.

[Methods for the evaluation of intestinal mucosal permeability].

The intestinal mucosal barrier (IMB), which consists of mechanical barrier, chemical barrier, biological barrier and immune barrier, plays an important role in the maintenance of intestinal epithelium integrity and defense against invasion of bacteria, endotoxins and foreign antigens. Impaired IMB, characterized by increased intestinal mucosal permeability (IMP) and decreased transmembrane resistance (TR), has been implicated in the pathogenesis of various digestive, urinary, circulatory, neurological and metabolic dysfunctions. Electrophysiological recording of TR in the ex vivo intestinal tissues or cultured epithelial cell monolayers, or biochemical quantification of transepithelial movement of orally-administered molecular probes or specific endogenous protein molecules has frequently been used in the evaluation of IMB. In this paper, the composition and function of IMB will be summarized, with emphasis on the evaluation methods of IMP.

Reduced acetylcholine and elevated muscarinic receptor 2 in duodenal mucosa contribute to the impairment of mucus secretion in 6-hydroxydopamine-induced Parkinson's disease rats.

Patients with Parkinson's disease (PD) have a higher incidence rate of duodenal ulcers. The mucus barrier provides the first line of defense for duodenal mucosal protection. However, it is unknown whether duodenal mucus secretion is affected in PD. In the present study, we used the rats microinjected 6-hydroxydopamine (6-OHDA) into the bilateral substantia nigra to investigate duodenal mucus secretion and potential therapeutic targets in duodenal ulcer in PD. Alcian blue-periodic acid-Schiff, transmission electron microscopy, immunofluorescence, duodenal mucosal incubation, and enzyme-linked immunosorbent assays were used. The 6-OHDA rats exhibited mucin accumulation and retention in duodenal goblet cells. Mucin granules were unable to fuse with the apical membranes of goblet cells, and the exocytosis ratio of goblet cells was significantly reduced. Moreover, decreased acetylcholine and increased muscarinic receptor 2 (M2R) levels were detected in the duodenal mucosa of 6-OHDA rats. Bilateral vagotomy rats were also characterized by defective duodenal mucus secretion and decreased acetylcholine with increased M2R levels in the duodenal mucosa. Application of the cholinomimetic drug carbachol or blocking M2R with methoctramine significantly promoted mucus secretion by goblet cells and increased MUC2 content in duodenal mucosa-incubated solutions from 6-OHDA and vagotomy rats. We conclude that the reduced acetylcholine and increased M2R contribute to the impaired duodenal mucus secretion of 6-OHDA rats. The study provides new insights into the mechanism of duodenal mucus secretion and potential therapeutic targets for the treatment of duodenal ulcers in PD patients.

Clinical Value of Serum LHPP-associated miR-765 in the Prognosis of Laparoscopic or Open Hepatectomy for Hepatocellular Carcinoma.

PURPOSE: The current study aims to investigate the effect of tumor suppressor LHPP-associated microRNA (miR)-765 on the prognosis of laparoscopic hepatectomy (LH) or open hepatectomy (OH) for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 160 patients with HCC were enrolled and randomly divided into the LH or OH group. According to the operation time, these patients were followed up for 12 months, and the number of deaths and the corresponding death time during the follow-up period were counted. RESULTS: The authors found that the LHPP gene levels in HCC tissues were lower than that in adjacent normal tissues, whereas miR-765 was overexpressed in HCC tissue. Overexpression of miR-765 promoted the epithelial-mesenchymal transition and proliferation and inhibited apoptosis of HCC through directly downregulating LHPP expression. Serum miR-765 expression level was significantly associated with lymph node metastasis and histologic grading. Survival analysis showed that the overall survival rate in 12 months after the operation was significantly lower in the OH-high miR-765 group (P<0.05). CONCLUSION: For patients with a low miR-765 level, both LH and OH are available, otherwise, LH is more recommended.

Source of dopamine in gastric juice and luminal dopamine-induced duodenal bicarbonate secretion via apical dopamine D2 receptors.

BACKGROUND AND PURPOSE: Dopamine protects the duodenal mucosa. Here we have investigated the source of dopamine in gastric juice and the mechanism underlying the effects of luminal dopamine on duodenal bicarbonate secretion (DBS) in rodents. EXPERIMENTAL APPROACH: Immunofluorescence, UPLC-MS/MS, gastric incubation and perfusion were used to detect gastric-derived dopamine. Immunofluorescence and RT-PCR were used to examine the expression of dopamine receptors in the duodenal mucosa. Real-time pH titration and pHi measurement were performed to investigate DBS. KEY RESULTS: H+ -K+ -ATPase was co-localized with tyrosine hydroxylase and dopamine transporters in gastric parietal cells. Dopamine was increased in in vivo gastric perfusate after intravenous infusion of histamine and in gastric mucosa incubated, in vitro, with bethanechol chloride or tyrosine. D2 receptors were the most abundant dopamine receptors in rat duodenum, mainly distributed on the apical membrane of epithelial cells. Luminal dopamine increased DBS in a concentration-dependent manner, an effect mimicked by a D2 receptor agonist quinpirole and inhibited by the D2 receptor antagonist L741,626, in vivo D2 receptor siRNA and in D2 receptor -/- mice. Dopamine and quinpirole raised the duodenal enterocyte pHi . Quinpirole-evoked DBS and PI3K/Akt activity were inhibited by calcium chelator BAPTA-AM or in D2 receptor-/- mice. CONCLUSION AND IMPLICATIONS: Dopamine in the gastric juice is derived from parietal cells and is secreted along with gastric acid. On arrival in the duodenal lumen, dopamine increased DBS via an apical D2 receptor- and calcium-dependent pathway. Our data provide novel insights into the protective effects of dopamine on the duodenal mucosa.

Dopamine promotes colonic mucus secretion through dopamine D5 receptor in rats.

Dopamine regulates gastrointestinal mucosal barrier. Mucus plays important roles in the protection of intestinal mucosa. Here, the regulatory effect of dopamine on rat colonic mucus secretion was investigated. RT-PCR, immunofluorescence, Periodic Acid-Schiff reagent assay, Alcian blue-Periodic Acid-Schiff staining, and enzyme-linked immunosorbent assay were used to observe the expression of dopamine receptor and the direct effect of dopamine on the colonic mucus. Mice injected intraperitoneally with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) destroying enteric dopamine (DA) neurons, rats microinjected with 6-hydroxydopamine (6-OHDA) into the bilateral substantia nigra damaging central dopaminergic neurons, and dopamine D5 receptor-downregulated transgenic mice were used to detect the effect of endogenous enteric dopamine or dopamine receptors on distal colonic mucus. Our results indicated that D5 immunoreactivity was widely distributed on the colonic goblet cells. Dopamine dose-dependently increased rat distal colonic mucus secretion in vitro. D1-like receptor antagonist SCH23390 inhibited dopamine (1 µΜ)-induced distal colonic mucus secretion. D1-like receptor agonist SKF38393 promoted mucin 2 (MUC2) secretion and increased the intracellular cAMP level of colonic mucosa. D5 receptor-downregulated transgenic mice showed a decreased colonic MUC2 content. MPTP-treated mice exhibited lower colonic dopamine content and decreased colonic mucus content. 6-OHDA rats had an increase in the dopamine content in colonic mucosa but decreases in the protein levels of D1 and D5 receptors and MUC2 content in the colonic mucosa. These findings reveal that dopamine is able to promote distal colonic mucus secretion through the D5 receptor, which provides important evidence to better understand the possible role of dopamine in the colonic mucosal barrier.

Hyperlipidemia exacerbates cerebral injury through oxidative stress, inflammation and neuronal apoptosis in MCAO/reperfusion rats.

Recent studies showed that hyperglycemia enhanced brain damage when subjected to transient cerebral ischemic stroke. However, the etiologic link between them has been less known. In the present study, based on an experimental rat's model of hyperlipidemia combined with cerebral ischemia-reperfusion injury (I/R), we herein showed that hyperlipidemia induced by high-fat diet (HFD) resulted in considerable increase in serum triglycerides, cholesterol and low-density lipoprotein cholesterol, and remarkable decrease in serum high-density lipoprotein cholesterol, which associated with an exacerbation on neurological deficit, cerebral infarct and terminal deoxynucleotidyl transferase-mediated nick end labeling-positive cells in the ischemic hemisphere of cerebral I/R rats treated with HFD diet. The data showed that serum superoxide dismutase activity and glutathione peroxides content were significantly decreased, while malondialdehyde level was obviously increased by hyperlipidemia or cerebral I/R alone, especially by coexistence of hyperlipidemia and cerebral I/R; meantime, hyperlipidemia also enhanced cerebral I/R-induced protein expression of cytochrome P450 2E1 (CYP2E1) and the levels of pro-inflammatory factors tumor necrosis factor-α and IL-6 in the ischemic hemispheres. Furthermore, the combined action of hyperlipidemia and cerebral I/R resulted in a protein increase expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 compared to hyperlipidemia or cerebral I/R alone. Meanwhile, this study also showed that hyperlipidemia significantly enhanced cerebral I/R-induced transfer of cytochrome c from mitochondria to cytosolic and the protein expressions of Apaf-1 and caspase-3, but also decreased cerebral I/R-induced bcl-2 protein expression. The results reveal that hyperlipidemia exacerbates cerebral I/R-induced injury through the synergistic effect on CYP2E1 induction, which further induces reactive oxygen species formation, oxidative stress, inflammation and neuronal apoptosis by coexistence of hyperlipidemia and cerebral I/R.