Burden In Mouse Model Research Articles

Senkyunolide B exhibits broad-spectrum antifungal activity against plant and human pathogenic fungi via inhibiting spore germination and destroying the mature biofilm.

Aspergillus infection seriously jeopardize the health and safety of life of immunocompromised patients. The emergences of antifungal resistance highlight a demand to find new effective antifungal drugs. Angelica sinensis is a medicine-food herb and phthalides are its characteristic components. A few of phthalides have been reported to display satisfactory antifungal activities against plant pathogenic fungi. However, the structure activity relationships and antifungal action mechanism of phthalides remain to be further explored and elucidated. The antifungal activities of five natural phthalides and four artificial analogues were investigated, and their structure activity relationships were preliminarily elucidated in current study. The benzene ring moiety played an essential role in their antifungal activities; the oxygen-containing substituents on the benzene ring obviously impact their activities, the free hydroxyl was favorable to the activity. Typical phthalide senkyunolide B (SENB) exhibited broad antifungal activities against human and plant pathogenic fungi, especially, Aspergillus fumigatus. SENB affected the spore germination and hyphae growth of A. fumigatus via downregulating phosphatidylinositol-PKC-calcineurin axis and the expression of ENG genes. Moreover, SENB disturbed the oxidation-reduction process in A. fumigatus to destroy the mature biofilms. In vivo experiments indicated SENB significantly prolonged survival and decreased fungal burden in mouse model of invasive pulmonary aspergillosis. Phthalides could be considered as the valuable leads for the development of antifungal drug to cure plant and human disease. This article is protected by copyright. All rights reserved.

A semisynthetic borrelidin analogue BN-3b exerts potent antifungal activity against Candida albicans through ROS-mediated oxidative damage

In the process of investigating the antifungal structure-activity relationships (SAR) of borrelidin and discovering antifungal leads, a semisynthetic borrelidin analogue, BN-3b with antifungal activity against Candida albicans, was achieved. In this study, we found that oxidative damage induced by endogenous reactive oxygen species (ROS) plays an important role in the antifungal activity of BN-3b. Further investigation indicated that BN-3b stimulated ROS accumulation, increased malondialdehyde (MDA) levels, and decreased reduced/oxidized glutathione (GSH/GSSG) ratio. Moreover, BN-3b decreased mitochondrial membrane potential (MMP) and ATP generation. Ultrastructure analysis revealed that BN-3b severely damaged the cell membrane of C. albicans. Quantitative PCR (RT-qPCR) analysis revealed that virulence factors of C. albicans SAPs, PLB1, PLB2, HWP1, ALSs, and LIPs were all down-regulated after BN-3b exposure. We also found that BN-3b markedly inhibited the hyphal formation of C. albicans. In addition, in vivo studies revealed that BN-3b significantly prolonged survival and decreased fungal burden in mouse model of disseminated candidiasis.

104. Zoledronic acid decreases infection burden in mouse model of spine implant Infection

BACKGROUND CONTEXT Bisphosphonates are commonly used in the orthopedic patient population to manage osteoporosis and other metabolic bone diseases. There is also increasing support for bisphosphonate use in the perioperative setting, to minimize osteolysis and bone loss. Additionally, bisphosphonates are known to affect the host immune system; however, their effect on implant infections, which are notoriously difficult to treat, remains largely unknown. PURPOSE The purpose of this study was to assess the effect of zoledronic acid (ZA) on spinal implant infection in our validated mouse model. METHODS Twenty-six 8-week-old C57BL/6 mice were included in the study. Twelve were treated with 250 ug/kg of ZA,12 with normal saline via retro-orbital injection on the day of surgery, and the remaining 2 were sterile controls. A stainless steel pin was then placed into the L4 spinous processes of all mice and site was inoculated with 1E+3 CFUs of bioluminescent Xen36 Staphylococcus aureus in experimental groups. Infection burden was monitored with in vivo bioluminescence imaging at pre-determined intervals. RESULTS Following an initial similar increase after surgery and inoculation, mice treated with ZA showed a decreased bacterial burden as compared to infected control group (p CONCLUSIONS The indications for ZA use continue to expand, and it is often used in the perioperative setting. In our validated mouse model of spine implant infection, ZA decreases bacterial burden as compared to controls. Further investigation is required to determine the effects of dosing, location of infection and to explore possible mechanisms by which ZA exerts this effect. These findings may suggest a further benefit to bisphosphonate use in the perioperative setting. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

Abstract A42: TWIST1 as a driver of accelerated tumor growth and drug resistance: Potential novel pathways and therapeutics.

Abstract Introduction: Epithelial ovarian cancer (EOC) is particularly deadly due to its fast rate of growth, dissemination, and chemoresistant recurrences. Novel therapies are urgently needed to limit metastasis and restore platinum sensitivity. We have investigated the role of TWIST1, a basic helix-loop-helix transcription factor, in these processes. TWIST1 is a well-documented regulator of metastasis from solid tumors, which has been linked to cancer stem cell phenotypes, drug resistance, and poor prognosis in several tumor types. Here we present in vitro and in vivo data supporting TWIST1's role in EOC growth and drug resistance, and propose a therapeutic modality to target TWIST1. Methodology: In vitro and in vivo studies: We created two cell lines, derived from the EOC line OVCAR8, that differ only in their TWIST1 expression. The cells were stably transfected with a G418-selectible vector containing either TWIST1 or an shRNA targeting TWIST1, under the control of the CMV viral promoter. Cells from each line were injected IP (intraperitoneally) into NSG mice, allowed to grow for 7 weeks, and tumor burden was evaluated at necropsy. In addition, RNA from each of these OVCAR8 cell lines (TWIST1 overexpressing versus knockdown) was isolated and used for RNA-seq analysis. Raw data was processed using the Galaxy online platform, and differentially expressed genes were further analyzed using Ingenuity Pathway Analysis. To determine the effect of TWIST1 on drug resistance, OVCAR8 cells with and without TWIST1 were treated with varying doses of cisplatin, and survival was quantified using colorimetric cytotoxicity assays. Therapeutic Application: Since we and others have shown that TWIST1's transactivation/protein binding (WR) domain is required for TWIST1 function, we produced a fusion protein comprised of GFP and the WR domain, and used CoIP to evaluate its ability to competitively inhibit TWIST1 binding in HEK 293 cells. Results: TWIST1 knockdown resulted in reduced tumor size and overall tumor burden in an NSG mouse model of EOC. Specifically, all mice receiving TWIST1-overexpressing cells developed primary ovarian tumors which were scored +4 on H&E by a veterinary pathologist, whereas only 50% of animals with TWIST1 knockdown developed ovarian tumors, and only 1 of 4 mice had a tumor that scored +4. In addition, fewer metastases were present in mice receiving TWIST knockdown cells, and no mice with TWIST1 knockdown tumors produced ascites. RNA-seq analysis of the TWIST overexpressing versus knockdown cell lines revealed marked differences in genes and pathways responsible for cell migration and cell survival, including upregulation of genes implicated in metastasis, DNA repair, and resistance to apoptosis in TWIST1 overexpressing cells. TWIST1 overexpressing cells also showed less cell death following cisplatin treatment. Finally, in our in vitro inhibitor tests, a GFP-WR domain fusion protein successfully reduced TWIST1 binding to its partner protein NFkB-p65 in HEK 293 cells. Conclusions: The importance of TWIST1 for tumor growth has been demonstrated for multiple tumor types – including ovarian cancer, as presented here. Our RNA-seq analysis reveals a complex network of TWIST1-mediated factors implicated in cell movement, survival, and resistance to DNA damaging agents, and we are working to determine the most important of these pathways in EOC. Most importantly, we have shown that TWIST1 expression in EOC cells leads to greater tumor burden in a mouse model, and by knocking down TWIST1, we were able to prevent peritoneal metastases and reduce tumor size. Therefore, we believe that TWIST1 is an attractive therapeutic target in EOC, owing to its roles at the crossroads of metastasis, drug resistance, and tumor growth. Citation Format: Cai M. Roberts, Michelle A. Tran, James Finlay, Sophia Allaf Shahin, Joana Loeza, Leslie Cisneros, Emily Ye, Thanh Dellinger, Carlotta A. Glackin. TWIST1 as a driver of accelerated tumor growth and drug resistance: Potential novel pathways and therapeutics. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A42.

Gene delivery of human apolipoprotein E alters brain Aβ burden in a mouse model of Alzheimer's disease

Apolipoprotein E (apoE) alleles are important genetic risk factors for Alzheimer's disease (AD), with the epsilon4 allele increasing and the epsilon2 allele decreasing risk for developing AD. ApoE has been shown to influence brain amyloid-beta peptide (Abeta) and amyloid burden, both in humans and in transgenic mice. Here we show that direct intracerebral administration of lentiviral vectors expressing the three common human apoE isoforms differentially alters hippocampal Abeta and amyloid burden in the PDAPP mouse model of AD. Expression of apoE4 in the absence of mouse apoE increases hippocampal Abeta(1-42) levels and amyloid burden. By contrast, expression of apoE2, even in the presence of mouse apoE, markedly reduces hippocampal Abeta burden. Our data demonstrate rapid apoE isoform-dependent effects on brain Abeta burden in a mouse model of AD. Gene delivery of apoE2 may prevent or reduce brain Abeta burden and the subsequent development of neuritic plaques.