Multi-step strategies for synergistic treatment of urinary tract infections based on D-xylose-decorated antimicrobial peptide carbon dots

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC), often reoccur due to the formation of intracellular bacterial colonies (IBCs) and antibiotic resistance. Given the significance of YadC for UPEC infection in our previous study, we developed D-xylose-decorated ɛ-poly-L-lysine (εPL)-based carbon dots (D-xyl@εPLCDs) that can be traced, and employed multi-step approaches to elucidate the functional roles of D-xyl@εPLCDs in UPEC infection. Compared to undecorated particles, D-xyl@εPLCDs demonstrate YadC-dependent bacterial targeting and exhibit enhanced bactericidal activities both intracellularly and extracellularly. Moreover, pre-treatment of D-xyl@εPLCDs before infection blocked the subsequent adhesion and invasion of UPEC to bladder epithelial cells 5637. Increase of ROS production and innate immune responses were observed in bladder epithelial cells 5637 treated with D-xyl@εPLCDs. In addition, treatment of D-xyl@εPLCDs post-infection facilitated clearance of UPEC in the bladders of the UTI mouse model, and reduced ultimate number of neutrophils, macrophages and inflammatory responses raised by invaded bacteria. Collectively, we presented a comprehensive evaluating system to show that D-xyl@εPLCDs exhibits superior bactericidal effects against UPEC, making them a promising candidate for drug development in clinical UTI therapeutics.

Bacterial indole-3-lactic acid affects epithelium-macrophage crosstalk to regulate intestinal homeostasis

Tryptophan and its derivatives perform a variety of biological functions; however, the role and specific mechanism of many tryptophan derivatives in intestinal inflammation remain largely unclear. Here, we identified that an Escherichia coli strain (Ec-TMU) isolated from the feces of tinidazole-treated individuals, and indole-3-lactic acid (ILA) in its supernatant, decreased the susceptibility of mice to dextran sulfate sodium-induced colitis. Ec-TMU and ILA contribute to the relief of colitis by inhibiting the production of epithelial CCL2/7, thereby reducing the accumulation of inflammatory macrophages in vitro and in vivo. Mechanistically, ILA downregulates glycolysis, NF-κB, and HIF signaling pathways via the aryl hydrocarbon receptor, resulting in decreased CCL2/7 production in epithelial cells. Clinical evidence suggests that the fecal ILA level is negatively correlated with the progression indicator of inflammatory bowel diseases. These results demonstrate that ILA has the potential to regulate intestinal homeostasis by modulating epithelium-macrophage interactions.

Aberrant metabolic processes promote the immunosuppressive microenvironment in multiple myeloma

Introduction

Multiple myeloma (MM) is still an incurable plasma cell malignancy. The efficacy of immunotherapy on MM remains unsatisfactory, and the underlying molecular mechanisms still are not fully understood.

Methods

In this study, we delineated the dynamic features of immune cell in MM bone marrow (BM) along with elevated tumor cell infiltration by single-cell RNA sequencing (scRNA-seq), and investigated the underlying mechanisms on dysfunction of immune cells associated with myelomagenesis.

Results

We found that immune cells were activated in those patients with low infiltration of tumor cells, meanwhile suppressed with elevated infiltration of MM cells, which facilitated MM escaping from immune surveillance. Besides PD-1, abnormal expression of PIM kinases, KLRB1 and KLRC1 were involved in the defect of immune cells in MM patients. Importantly, we found aberrant metabolic processes were associated with the immunosuppressive microenvironment in MM patients. Disordered amino acid metabolism promoted the dysfunction of cytotoxicity CD8 T cells as well as lipid metabolism disorder was associated with the dysregulation of NK and DCs in MM. As metabolic checkpoints, PIM kinases would be potential effective strategies for MM immunotherapy.

Discussion

In summary, redressing the disordered metabolism should be the key points to get promising effects in immune-based therapies.

Enterobacter ludwigii protects DSS-induced colitis through choline-mediated immune tolerance

Commensal intestinal bacteria play key roles in regulating host immune tolerance; however, bacterial strains and related metabolites directly involved in this regulation are largely unknown. Here, using a mouse model of dextran sulfate sodium (DSS)-induced colitis combined with different antibiotic treatment, Enterobacter ludwigii, abundant in microbiota of mice treated with metronidazole, is screened out to have prophylactic and therapeutic effects on DSS-induced colitis with or without the presence of complex intestinal bacteria. E. ludwigii is found to induce CD103⁺DC and regulatory T (Treg)-mediated immune tolerance for colitis remission using in vitro and in vivo experiments. Moreover, choline, one metabolite of E. ludwigii, is identified to increase dendritic cells' (DCs) immune tolerance to promote Treg differentiation. E. ludwigii is found to induce DCs' immune tolerance ability for Treg differentiation through choline and α7nAChR-mediated retinoic acid (RA) and transforming growth factor beta (TGF-β) upregulation, resulting in protecting mice against DSS-induced colitis. This study suggests potential therapeutic approaches for inflammatory bowel diseases (IBDs).

An infection-induced RhoB-Beclin 1-Hsp90 complex enhances clearance of uropathogenic Escherichia coli

Host cells use several anti-bacterial pathways to defend against pathogens. Here, using a uropathogenic Escherichia coli (UPEC) infection model, we demonstrate that bacterial infection upregulates RhoB, which subsequently promotes intracellular bacteria clearance by inducing LC3 lipidation and autophagosome formation. RhoB binds with Beclin 1 through its residues at 118 to 140 and the Beclin 1 CCD domain, with RhoB Arg133 being the key binding residue. Binding of RhoB to Beclin 1 enhances the Hsp90-Beclin 1 interaction, preventing Beclin 1 degradation. RhoB also directly interacts with Hsp90, maintaining RhoB levels. UPEC infections increase RhoB, Beclin 1 and LC3 levels in bladder epithelium in vivo, whereas Beclin 1 and LC3 levels as well as UPEC clearance are substantially reduced in RhoB^+/− and RhoB^−/− mice upon infection. We conclude that when stimulated by UPEC infections, host cells promote UPEC clearance through the RhoB-Beclin 1-HSP90 complex, indicating RhoB may be a useful target when developing UPEC treatment strategies.

Bacterial invasion can lead to multiple host cell responses. Here, the authors show that in a model of uropathogenic E. coli, RhoB is upregulated and induces autophagosome formation in a complex with Beclin1 and Hsp90, promoting bacterial clearance.

Herbal formula of Bushen Jianpi combined with sorafenib inhibits hepatocellular carcinoma growth by promoting cell apoptosis and blocking the cell cycle

OBJECTIVE

To investigate the efficacy of an herbal formula of Bushen Jianpi ( BSJP) combined with sorafenib on hepatocellular carcinoma (HCC) in vitro and in vivo, and to study the underlying mechanisms of action.

METHODS

BSJP, a mixture of 12 raw herbs, was extracted in 70% alcohol/30% water and freeze-dried into a powder. The in vitro effects of BSJP alone, sorafenib alone, and their combination on cell survival, apoptosis, and cell cycle distribution were evaluated in HCC cell lines HCCLM3, HepG2, and SMMC-7721. The expression of B-cell lymphoma-2 (Bcl-2), caspase-3, and caspase-9 in HCCLM3 cells was measured using Western blots after drug administration. The in vivo effects of BSJP and sorafenib were evaluated in a tumor surgical resection model using 4-week old male athymic BALB/c nude mice injected with HCCLM3 cells. Immunohistochemical analysis of tumor tissues was performed to evaluate the effects of BSJP alone, sorafenib alone, and their combination on the expression of caspase-3, caspase-9, and Bcl-2.

RESULTS

BSJP decreased the survival rate of HCC cell lines, and the combination of BSJP and sorafenib further decreased the survival rate. BSJP significantly promoted cell apoptosis and blocked cell-cycle progression in HCCLM3, HepG2, and SMMC-7721 cells in a dose-dependent manner. Furthermore, the administration of BSJP and sorafenib inhibited the growth of HCCLM3 cell xenografts in nude mice, with no reduction in body weight. In vivo and in vitro experiments showed that BSJP combined with sorafenib could significantly decrease the expression of Bcl-2.

CONCLUSION

Our findings suggest that the herbal formula of BSJP is a potential HCC antitumor agent.

Cytotoxic necrotizing factor 1 promotes bladder cancer angiogenesis through activating RhoC

Uropathogenic Escherichia coli (UPEC), a leading cause of urinary tract infections, is associated with prostate and bladder cancers. Cytotoxic necrotizing factor 1 (CNF1) is a key UPEC toxin; however, its role in bladder cancer is unknown. In the present study, we found CNF1 induced bladder cancer cells to secrete vascular endothelial growth factor (VEGF) through activating Ras homolog family member C (RhoC), leading to subsequent angiogenesis in the bladder cancer microenvironment. We then investigated that CNF1-mediated RhoC activation modulated the stabilization of hypoxia-inducible factor 1α (HIF1α) to upregulate the VEGF. We demonstrated in vitro that active RhoC increased heat shock factor 1 (HSF1) phosphorylation, which induced the heat shock protein 90α (HSP90α) expression, leading to stabilization of HIF1α. Active RhoC elevated HSP90α, HIF1α, VEGF expression, and angiogenesis in the human bladder cancer xenografts. In addition, HSP90α, HIF1α, and VEGF expression were also found positively correlated with the human bladder cancer development. These results provide a potential mechanism through which UPEC contributes to bladder cancer progression, and may provide potential therapeutic targets for bladder cancer.

Alpha-hemolysin of uropathogenic Escherichia coli induces GM-CSF-mediated acute kidney injury

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs), inducing acute pyelonephritis and may result in permanent renal scarring and failure. Alpha-hemolysin (HlyA), a key UPEC toxin, causes serious tissue damage; however, the mechanism through which HlyA induces kidney injury remains unclear. In the present study, granulocyte-macrophage colony-stimulating factor (GM-CSF) secreted by renal epithelial cells was upregulated by HlyA in vitro and in vivo, which induced M1 macrophage accumulation in kidney, and ADAM10 was found involved in HlyA-induced GM-CSF. Macrophage elimination or GM-CSF neutralization protected against acute kidney injury in mice, and increased GM-CSF was detected in urine of patients infected by hlyA-positive UPEC. In addition, HlyA was found to promote UPEC invasion into renal epithelial cells by interacting with Nectin-2 in vitro. However, HlyA did not affect bacterial titers during acute kidney infections, and HlyA-induced invasion did not contribute to GM-CSF upregulation in vitro, which indicate that HlyA-induced GM-CSF is independent of bacteria invasion. The role of GM-CSF in HlyA-mediated kidney injury may lead to novel strategies to treat acute pyelonephritis.

Cytotoxic Necrotizing Factor 1 Downregulates CD36 Transcription in Macrophages to Induce Inflammation During Acute Urinary Tract Infections

Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) induce cystitis, pyelonephritis, and can cause kidney scarring and failure if inflammation is not under control. The detailed effects of cytotoxic necrotizing factor 1 (CNF1), the key UPEC toxin, on the pathogenicity of UPEC remain unclear. CD36 is an important scavenger receptor, responsible for pathogen and apoptotic cell clearance, and plays an essential role in host immune defense and homeostasis. Regulation of CD36 by bacterial toxins has not been reported. In this study, using a pyelonephritis mouse model, CNF1 was observed to contribute to increasing neutrophils and bacterial titers in infected bladder and kidney tissues, resulting in severe inflammation and tissue damage. CD36 expression in macrophages was found to be decreased by CNF1 in vitro and in vivo. We demonstrated that CNF1 attenuated CD36 transcription by decreasing expressions of its upstream transcription factors LXRβ and C/EBPα and their recruitment to the CD36 promotor. In addition, Cdc42 was found to be involved in CNF1-mediated downregulation of LXRβ. Our study investigated the pathogenesis of cnf1-carrying UPEC, which affected host innate immune defenses and homeostasis through regulation of CD36 in macrophages during acute UTIs.

FBXL10 contributes to the development of diffuse large B-cell lymphoma by epigenetically enhancing ERK1/2 signaling pathway

Epigenetic modifiers have emerged as critical factors governing the biology of different cancers. Herein we show that FBXL10 (also called KDM2B or JHDM1B), an important member of Polycomb repressive complexes, is overexpressed in human diffuse large B-cell lymphoma (DLBCL) tissues and the derived cell lines. Knocking down FBXL10 by specific short hairpin RNAs in DLBCL cells inhibits cell proliferation and induces apoptosis in vitro. Moreover, FBXL10 depletion in DLBCL cells abrogates tumor growth in mouse xenograft models. Through the analysis of RNA sequencing, we find that one of the key derepressed genes by depletion of FBXL10 is DUSP6, encoding a phosphatase for ERK1/2. Mechanistically FBXL10 maintains the silencing of DUSP6 expression via recruitment of Polycomb group proteins and deposition of repressive histone modifications at the DUSP6 promoter. Consistently, FBXL10 is required for ERK1/2 phosphorylation in DLBCL cells. Furthermore, we show that ERK1/2 activation and the proliferation rate of FBXL10-depleted cells can be rescued by downregulation of DUSP6 expression. These findings indicate that FBXL10 may be a promising therapeutic target in DLBCL and establish a link of epigenetic regulators to kinase signaling pathways.

Cytotoxic necrotizing factor 1 promotes prostate cancer progression through activating the Cdc42-PAK1 axis

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections and plays a role in prostatic carcinogenesis and prostate cancer (PCa) progression. However, the mechanisms through which UPEC promotes PCa development and progression are unclear. Cytotoxic necrotizing factor 1 (CNF1) is one of the most important UPEC toxins and its role in PCa progression has never been studied. We found that UPEC-secreted CNF1 promoted the migration and invasion of PCa cells and PCa metastasis. In vitro studies showed that CNF1 promotes pro-migratory and pro-invasive activity through entering PCa cells and activating Cdc42, which subsequently induced PAK1 phosphorylation and up-regulation of MMP-9 expression. CNF1 also promoted pulmonary metastasis in a xenograft mouse model through these mechanisms. PAK1 phosphorylation correlated with advanced grades of PCa in human clinical PCa tissues. These results suggest that CNF1 derived from UPEC plays an important role in PCa progression through activating a Cdc42-PAK1 signal axis and up-regulating the expression of MMP-9. Therefore, surveillance for and treatment of cnf1-carrying UPEC strains may diminish PCa progression and thus have an important clinical therapeutic impact. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Effects of Tyroserleutide on phosphatidylinositol 3'-kinase/AKT pathway in human hepatocellular carcinoma cell

Tyroserleutide (YSL) is an active, low-molecular-weight polypeptide with in vitro and in vivo anticancer effects on human hepatocellular carcinoma BEL-7402 cells. In this study, we studied the effects of YSL on PI3K/AKT in the BEL-7402 cells to explore its anti-tumor mechanism. Results showed that YSL could up-regulate the mRNA and protein expression of tumor suppressor PTEN and increase their activities, meanwhile inhibited the mRNA and protein expression of oncogene AKT and decreased the kinase activities of AKT and PDK1. The resuming balance effect of YSL between PTEN and AKT could prevent the transmission of tumor cell proliferation signals in the PI3K/AKT pathway. Inhibition of AKT would change the status of downstream effectors in the PI3K/AKT pathway: (1) inhibition of AKT up-regulated expression of cell cycle regulatory factors of downstream - P21 and P27 which repressed cell cycle and inhibited proliferation of tumor cells. (2) Inhibition of AKT decreased the phosphorylation level of MDM2, and then increased the protein level of P53 which would accelerate death proceeding of tumor cells. (3) Inactivation of AKT removed its inhibition effect on phosphorylation of Bad, which might decrease protein level of apoptosis inhibitor Bcl-2 and Bcl-XL, damaging mitochondria of tumor cells and inducing apoptosis.

Expression, purification, and activity assay of peptide deformylase from Escherichia coli and Staphylococcus aureus

Peptide deformylase (PDF) is considered an attractive target for screening novel antibiotics. The PDF from Escherichia coli and Staphylococcus aureus are representative of the gram-negative species type of PDF (type I PDF) and the gram-positive species type of PDF (type II PDF), respectively. They could be used for screening broad-spectrum antibiotics. Herein, we cloned the def gene by PCR, inserted it into plasmid pET-22b-def, and transformed the plasmid into E. coli BL21 (DE3) cells, then the cells were induced by IPTG to express PDF. E. coli Ni(2+)-PDF was extracted and purified by ion-exchange chromatography and gel filtration chromatography. S. aureus PDFs were extracted and purified using the MagExtractor kit. The nickel form of S. aureus PDF was obtained by adding NiCl(2) to all reagents used for purification. Iron-enriched S. aureus PDF was obtained by adding FeCl(3) to the growth medium for E. coli BL21 (DE3) cells and adding FeCl(3) and catalase to all reagents used for purification. The activities of PDFs were analyzed, compared, and grouped according to the experimental conditions that produced optimal activity, and we used actinonin as an inhibitor of PDF and calculated the IC(50) value. We obtained high expression of E. coli and S. aureus PDF with high activity and stability. The function of PDFs was inhibited by actinonin in a dose-dependent manner. Results may be helpful for future mechanistic investigations of PDF as well as high-throughput screening for other PDF inhibitors.

Over-expression of protein kinase C isoforms (α, δ, θ and ζ) in squamous cervical cancer

Protein kinase C was found to be significantly over-expressed in cancer samples compared to adjacent normal cervical tissues by proteomics in our previous study. The aim of this study was to examine protein kinase C expression and to analyze the expression patterns of protein kinase C isoforms in squamous cervical cancer at the protein levels and their associations with clinical and pathologic factors of squamous cervical cancer. First, Western blotting was used to examine protein kinase C expression in the specimens of tumors and matched adjacent normal tissues which were collected from 12 patients with squamous cervical cancer. Protein kinase C isoforms (α, δ, θ and ζ) expression were then detected by immunohistochemistry in other 43 cases of squamous cervical cancer tissues, 32 cases of corresponding adjacent normal cervical squamous epithelial tissue and 31 cases of cervical intraepithelial neoplasia. Western blot analysis revealed that protein kinase C expression was positive in squamous cervical cancer while it was not expressed in normal cervical tissues. On the other hand, immunohistochemical analysis suggested that, protein kinase C isoforms (α, δ, θ and ζ) expression was significantly higher in squamous cervical cancer compared to cervical intraepithelial neoplasia, as well as in cervical intraepithelial neoplasia compared with normal tissues, respectively.High levels of protein kinase C α expression were associated with cellular differentiation(P<0.05). Protein kinase C δ was significantly associated with tumor stage (P<0.05) and protein kinase C ζ was associated with lymphatic metastasis (P < 0.05). These findings indicate that protein kinase C isoforms expression in cervical lesions was associated with carcinogenesis and might play important roles throughout the process of cervical cancer development.

The new immunosuppressant PLNPK prolongs allograft survival in mice

The pentapeptide PLNPK (Pro-Leu-Asn-Pro-Lys) is extracted from the spleen. Preliminary studies have shown that PLNPK could inhibit T lymphocyte transformation and antibody production. In the present study, we detected the inhibitory effect of PLNPK on one-way mixed leukocyte reaction (MLR) in vitro and observed the effect of PLNPK on the duration of allograft survival in mouse models of skin or cardiac transplantation. Pathological damage and T cell infiltration of the grafts were also detected. Results showed that PLNPK could significantly inhibit T lymphocyte proliferation, with an optimized inhibition of 40%. Also PLNPK could significantly prolong the mean survival time of skin allograft and cardiac allograft, producing survival rates of 42% and 38.7%, respectively. PLNPK at a dose of 200 μg/kg/d or 100 μg/kg/d could significantly suppress ConA-induced T cell proliferation and T cell IL-2 secretion in transplant recipient mice, compared to the saline group (P<0.05). This information suggests that PLNPK can effectively antagonize transplant rejection, possibly by reducing IL-2 secretion by T cells and inhibiting T cell proliferation and activation.

A new pentapeptide compound, PLNPK, ameliorates anti-glomerular basement membrane nephritis in Wistar rats

PLNPK is a pentapeptide compound extracted from pig spleen with a Pro-Leu-Asn-Pro-Lys molecular structure. The spleen is the biggest immune organ in the body, in which there are lots of immunocytes and immune molecules. Our pilot study showed that PLNPK could suppress the transformation and proliferation of T lymphocytes and the production of antibodies in mice. It is widely accepted that most types of glomerulonephritis are immunological diseases caused by the reaction of antigen and antibody. Both humoral immunity and cell-mediated immunity contribute to the progress of these diseases, and suppression of immunoreactions and inflammation is important to ameliorate nephritis. After the immunosuppressive effects of this compound were discovered, this study also examined whether PLNPK had beneficial effects on a rat model of glomerulonephritis. The results suggested PLNPK (200microg/kg/d and 400microg/kg/d) reduced urinary protein excretion, lessened the deposit of autoantibodies along the glomerular basement membrane (GBM), reduced formation of crescent and protein casts, and ameliorated glomerular fibrosis and GBM injury. After treatment with PLNPK (200microg/kg/d and 400microg/kg/d) for 7 days, macrophage infiltration in the glomeruli was markedly reduced. Our results suggest that PLNPK has a beneficial effect on rat anti-GBM nephritis.

Characterization of complete genome sequence of the spring viremia of carp virus isolated from common carp (Cyprinus carpio) in China

The complete genome of spring viraemia of carp virus (SVCV) strain A-1 isolated from cultured common carp (Cyprinus carpio) in China was sequenced and characterized. Reverse transcription-polymerase chain reaction (RT-PCR) derived clones were constructed and the DNA was sequenced. It showed that the entire genome of SVCV A-1 consists of 11,100 nucleotide base pairs, the predicted size of the viral RNA of rhabdoviruses. However, the additional insertions in bp 4633-4676 and bp 4684-4724 of SVCV A-1 were different from the other two published SVCV complete genomes. Five open reading frames (ORFs) of SVCV A-1 were identified and further confirmed by RT-PCR and DNA sequencing of their respective RT-PCR products. The 5 structural proteins encoded by the viral RNA were ordered 3'-N-P-M-G-L-5'. This is the first report of a complete genome sequence of SVCV isolated from cultured carp in China. Phylogenetic analysis indicates that SVCV A-1 is closely related to the members of the genus Vesiculovirus, family Rhabdoviridae.