Functional Antibodies Targeting IsaA ofStaphylococcus aureusAugment Host Immune Response and Open New Perspectives for Antibacterial Therapy

ABSTRACTStaphylococcus aureusis the most common cause of nosocomial infections. Multiple antibiotic resistance and severe clinical outcomes provide a strong rationale for development of immunoglobulin-based strategies. Traditionally, novel immunological approaches against bacterial pathogens involve antibodies directed against cell surface-exposed virulence-associated epitopes or toxins. In this study, we generated a monoclonal antibody targeting the housekeeping protein IsaA, a suggested soluble lytic transglycosylase ofS. aureus, and tested its therapeutic efficacy in two experimental mouse infection models. A murine anti-IsaA antibody of the IgG1 subclass (UK-66P) showed the highest binding affinity in Biacore analysis. This antibody recognized allS. aureusstrains tested, including hospital-acquired and community-acquired methicillin-resistantS. aureusstrains. Therapeutic efficacyin vivoin mice was analyzed using a central venous catheter-related infection model and a sepsis survival model. In both models, anti-IsaA IgG1 conferred protection against staphylococcal infection.Ex vivo, UK-66P activates professional phagocytes and induces highly microbicidal reactive oxygen metabolites in a dose-dependent manner, resulting in bacterial killing. The study provides proof of concept that monoclonal IgG1 antibodies with high affinity to the ubiquitously expressed, single-epitope-targeting IsaA are effective in the treatment of staphylococcal infection in different mouse models. Anti-IsaA antibodies might be a useful component in an antibody-based therapeutic for prophylaxis or adjunctive treatment of human cases ofS. aureusinfections.

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Nanocrystals of Fusidic Acid for Dual Enhancement of Dermal Delivery and Antibacterial Activity: In Vitro, Ex Vivo and In Vivo Evaluation

Pharmaceutics ◽

10.3390/pharmaceutics12030199 ◽

2020 ◽

Vol 12 (3) ◽

pp. 199 ◽

Cited By ~ 2

Author(s):

Iman S. Ahmed ◽

Osama S. Elnahas ◽

Nouran H. Assar ◽

Amany M. Gad ◽

Rania El Hosary

Keyword(s):

Fusidic Acid ◽

Therapeutic Efficacy ◽

Ex Vivo ◽

Skin Permeation ◽

Fold Increase ◽

Spherical Particles ◽

Resistant Bacteria ◽

Infection Model

With the alarming rise in incidence of antibiotic-resistant bacteria and the scarcity of newly developed antibiotics, it is imperative that we design more effective formulations for already marketed antimicrobial agents. Fusidic acid (FA), one of the most widely used antibiotics in the topical treatment of several skin and eye infections, suffers from poor water-solubility, sub-optimal therapeutic efficacy, and a significant rise in FA-resistant Staphylococcus aureus (FRSA). In this work, the physico-chemical characteristics of FA were modified by nanocrystallization and lyophilization to improve its therapeutic efficacy through the dermal route. FA-nanocrystals (NC) were prepared using a modified nanoprecipitation technique and the influence of several formulation/process variables on the prepared FA-NC characteristics were optimized using full factorial statistical design. The optimized FA-NC formulation was evaluated before and after lyophilization by several in-vitro, ex-vivo, and microbiological tests. Furthermore, the lyophilized FA-NC formulation was incorporated into a cream product and its topical antibacterial efficacy was assessed in vivo using a rat excision wound infection model. Surface morphology of optimized FA-NC showed spherical particles with a mean particle size of 115 nm, span value of 1.6 and zeta potential of −11.6 mV. Differential scanning calorimetry and powder X-ray diffractometry confirmed the crystallinity of FA following nanocrystallization and lyophilization. In-vitro results showed a 10-fold increase in the saturation solubility of FA-NC while ex-vivo skin permeation studies showed a 2-fold increase in FA dermal deposition from FA-NC compared to coarse FA. Microbiological studies revealed a 4-fofd decrease in the MIC against S. aureus and S. epidermidis from FA-NC cream compared to commercial Fucidin cream. In-vivo results showed that FA-NC cream improved FA distribution and enhanced bacterial exposure in the infected wound, resulting in increased therapeutic efficacy when compared to coarse FA marketed as Fucidin cream.

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Therapeutic efficacy of BO-3482, a novel dithiocarbamate carbapenem, in mice infected with methicillin-resistant Staphylococcus aureus.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.41.10.2278 ◽

1997 ◽

Vol 41 (10) ◽

pp. 2278-2281 ◽

Cited By ~ 25

Author(s):

R Nagano ◽

K Shibata ◽

T Naito ◽

A Fuse ◽

K Asano ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Therapeutic Efficacy ◽

Methicillin Resistant Staphylococcus Aureus ◽

Infection Model ◽

Dependent Manner ◽

Methicillin Resistant ◽

Mrsa Strains ◽

Systemic Infections

The in vivo activity of BO-3482, which has a dithiocarbamate chain at the C-2 position of 1beta-methyl-carbapenem, was compared with those of vancomycin and imipenem in murine models of septicemia and thigh infection with methicillin-resistant Staphylococcus aureus (MRSA). Because BO-3482 was more susceptible than imipenem to renal dehydropeptidase I in a kinetic study of hydrolysis by this renal enzyme, the therapeutic efficacy of BO-3482 was determined during coadministration with cilastatin. In the septicemia models, which involved two homogeneous MRSA strains and one heterogeneous MRSA strain, the 50% effective doses were, respectively, 4.80, 6.06, and 0.46 mg/kg of body weight for BO-3482; 5.56, 2.15, and 1.79 mg/kg for vancomycin; and >200, >200, and 15.9 mg/kg for imipenem. BO-3482 was also as effective as vancomycin in an MRSA septicemia model with mice with cyclophosphamide-induced immunosuppression. In the thigh infection model with a homogeneous MRSA strain, the bacterial counts in tissues treated with BO-3482-cilastatin were significantly reduced in a dose-dependent manner compared with the counts in those treated with vancomycin and imipenem-cilastatin (P < 0.001). These results indicate that BO-3482-cilastatin is as effective as vancomycin in murine systemic infections and is more bactericidal than vancomycin in local-tissue infections. The potent in vivo activity of BO-3482-cilastatin against such MRSA infections can be ascribed to the good in vitro anti-MRSA activity and improved pharmacokinetics in mice when BO-3482 is combined with cilastatin and to the bactericidal nature of the carbapenem.

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Serine-Aspartate Repeat Protein D Increases Staphylococcus aureus Virulence and Survival in Blood

Infection and Immunity ◽

10.1128/iai.00559-16 ◽

2016 ◽

Vol 85 (1) ◽

Cited By ~ 9

Author(s):

Fatemeh Askarian ◽

Satoshi Uchiyama ◽

J. Andrés Valderrama ◽

Clement Ajayi ◽

Johanna U. E. Sollid ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Ex Vivo ◽

Innate Immune ◽

Human Neutrophils ◽

Infection Model ◽

Bacterial Survival ◽

Bacterial Killing ◽

Content Type ◽

Repeat Protein

ABSTRACT Staphylococcus aureus expresses a panel of cell wall-anchored adhesins, including proteins belonging to the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) family, exemplified by the serine-aspartate repeat protein D (SdrD), which serve key roles in colonization and infection. Deletion of sdrD from S. aureus subsp. aureus strain NCTC8325-4 attenuated bacterial survival in human whole blood ex vivo, which was associated with increased killing by human neutrophils. Remarkably, SdrD was able to inhibit innate immune-mediated bacterial killing independently of other S. aureus proteins, since addition of recombinant SdrD protein and heterologous expression of SdrD in Lactococcus lactis promoted bacterial survival in human blood. SdrD contributes to bacterial virulence in vivo, since fewer S. aureus subsp. aureus NCTC8325-4 ΔsdrD bacteria than bacteria of the parent strain were recovered from blood and several organs using a murine intravenous infection model. Collectively, our findings reveal a new property of SdrD as an important key contributor to S. aureus survival and the ability to escape the innate immune system in blood.

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Ethanol Extract of Achillea fragrantissima Enhances Angiogenesis through Stimulation of VEGF Production

Endocrine Metabolic & Immune Disorders - Drug Targets ◽

10.2174/1871530321666201230113018 ◽

2020 ◽

Vol 21 ◽

Author(s):

Hana M. Hammad ◽

Amer Imraish ◽

Maysa Al-Hussaini ◽

Malek Zihlif ◽

Amani A. Harb ◽

...

Keyword(s):

Wound Healing ◽

Rural Communities ◽

Ex Vivo ◽

Ethanol Extract ◽

Aortic Ring ◽

Treated Group ◽

Control Group ◽

Dependent Manner ◽

Achillea Fragrantissima

Objective: Achillea fragrantissima L. (Asteraceae) is a traditionally used medicinal herb in the rural communities of Jordan. Methods: The present study evaluated the efficacy of the ethanol extract of this species on angiogenesis in both, ex vivo using rat aortic ring assay and in vivo using rat excision wound model. Results: In concentrations of 50 and 100 µg/ml, the ethanol extract showed angiogenic stimulatory effect and significantly increased length of capillary protrusions around aorta rings of about 60% in comparison to those of untreated aorta rings. In MCF-7 cells, the ethanol extract of A. fragrantissima stimulates the production of VEGF in a dose-dependent manner. 1% and 5% of ethanol extract of A. fragrantissima containing vaseline based ointment was applied on rat excision wounds for six days and was found to be effective in wound healing and maturation of the scar. Both preparations resulted in better wound healing when compared to the untreated control group and vaseline-treated group. This effect was comparable to that induced by MEBO, the positive control. Conclusion: The results indicate that A. fragrantissima has a pro-angiogenic effect, which may act through the VEGF signaling pathway.

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Eap1p, an Adhesin That Mediates Candida albicans Biofilm Formation In Vitro and In Vivo

Eukaryotic Cell ◽

10.1128/ec.00049-07 ◽

2007 ◽

Vol 6 (6) ◽

pp. 931-939 ◽

Cited By ~ 96

Author(s):

Fang Li ◽

Michael J. Svarovsky ◽

Amy J. Karlsson ◽

Joel P. Wagner ◽

Karen Marchillo ◽

...

Keyword(s):

Candida Albicans ◽

Cell Adhesion ◽

Biofilm Formation ◽

Fungal Infections ◽

Gene Dosage ◽

Venous Catheter ◽

Flow Chamber ◽

Dependent Manner

ABSTRACT Candida albicans is the leading cause of systemic fungal infections in immunocompromised humans. The ability to form biofilms on surfaces in the host or on implanted medical devices enhances C. albicans virulence, leading to antimicrobial resistance and providing a reservoir for infection. Biofilm formation is a complex multicellular process consisting of cell adhesion, cell growth, morphogenic switching between yeast form and filamentous states, and quorum sensing. Here we describe the role of the C. albicans EAP1 gene, which encodes a glycosylphosphatidylinositol-anchored, glucan-cross-linked cell wall protein, in adhesion and biofilm formation in vitro and in vivo. Deleting EAP1 reduced cell adhesion to polystyrene and epithelial cells in a gene dosage-dependent manner. Furthermore, EAP1 expression was required for C. albicans biofilm formation in an in vitro parallel plate flow chamber model and in an in vivo rat central venous catheter model. EAP1 expression was upregulated in biofilm-associated cells in vitro and in vivo. Our results illustrate an association between Eap1p-mediated adhesion and biofilm formation in vitro and in vivo.

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Uptake and Distribution of Administered Bone Marrow Mesenchymal Stem Cell Extracellular Vesicles in Retina

Cells ◽

10.3390/cells10040730 ◽

2021 ◽

Vol 10 (4) ◽

pp. 730

Author(s):

Biji Mathew ◽

Leianne A. Torres ◽

Lorea Gamboa Gamboa Acha ◽

Sophie Tran ◽

Alice Liu ◽

...

Keyword(s):

Stem Cell ◽

Mesenchymal Stem Cell ◽

Extracellular Vesicles ◽

Time Course ◽

Ganglion Cells ◽

Ex Vivo ◽

Dependent Manner ◽

Paracrine Effects

Cell replacement therapy using mesenchymal (MSC) and other stem cells has been evaluated for diabetic retinopathy and glaucoma. This approach has significant limitations, including few cells integrated, aberrant growth, and surgical complications. Mesenchymal Stem Cell Exosomes/Extracellular Vesicles (MSC EVs), which include exosomes and microvesicles, are an emerging alternative, promoting immunomodulation, repair, and regeneration by mediating MSC’s paracrine effects. For the clinical translation of EV therapy, it is important to determine the cellular destination and time course of EV uptake in the retina following administration. Here, we tested the cellular fate of EVs using in vivo rat retinas, ex vivo retinal explant, and primary retinal cells. Intravitreally administered fluorescent EVs were rapidly cleared from the vitreous. Retinal ganglion cells (RGCs) had maximal EV fluorescence at 14 days post administration, and microglia at 7 days. Both in vivo and in the explant model, most EVs were no deeper than the inner nuclear layer. Retinal astrocytes, microglia, and mixed neurons in vitro endocytosed EVs in a dose-dependent manner. Thus, our results indicate that intravitreal EVs are suited for the treatment of retinal diseases affecting the inner retina. Modification of the EV surface should be considered for maintaining EVs in the vitreous for prolonged delivery.

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Skeletal muscle phenotype signaling with ex vivo endurance-type dynamic contractions in rat muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.00107.2021 ◽

2021 ◽

Author(s):

Jesper Emil Jakobsgaard ◽

Jacob Andresen ◽

Frank V. de Paoli ◽

Kristian Vissing

Keyword(s):

Skeletal Muscle ◽

Translation Initiation ◽

Ex Vivo ◽

Contractile Activity ◽

Specific Protein ◽

Signaling Proteins ◽

Dependent Manner ◽

Metabolic Signaling ◽

Dynamic Endurance

Skeletal muscle phenotype may influence the response sensitivity of myocellular regulatory mechanisms to contractile activity. To examine this, we employed an ex vivo endurance-type dynamic contraction model to evaluate skeletal muscle phenotype-specific protein signaling responses in rat skeletal muscle. Preparations of slow-twitch soleus and fast-twitch extensor digitorum longus skeletal muscle from 4-wk old female Wistar rats were exposed to an identical ex vivo dynamic endurance-type contraction paradigm consisting of 40 minutes of stretch-shortening contractions under simultaneous low-frequency electrostimulation delivered in an intermittent pattern. Phosphorylation of proteins involved in metabolic signaling and signaling for translation initiation was evaluated at 0, 1, and 4 hours after stimulation by immunoblotting. For both muscle phenotypes, signaling related to metabolic events was upregulated immediately after stimulation, with concomitant absence of signaling for translation-initiation. Signaling for translation-initiation was then activated in both muscle phenotypes at 1-4 hours after stimulation, coinciding with attenuated metabolic signaling. The recognizable pattern of signaling responses support how our ex vivo dynamic muscle contraction model can be utilized to infer a stretch-shortening contraction pattern resembling stretch-shortening contraction of in vivo endurance exercise. Moreover, using this model, we observed that some specific signaling proteins adhering to metabolic events or to translation initation exhibited phosphorylation changes in a phenotype-dependent manner, whereas other signaling proteins exhibited phenotype-independent changes. These findings may aid the interpretation of myocellular signaling outcomes adhering to mixed muscle samples collected during human experimental trials.

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The NADPH Oxidase Nox4 Controls Macrophage Polarization in an NFκB-Dependent Manner

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/3264858 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

V. Helfinger ◽

K. Palfi ◽

A. Weigert ◽

K. Schröder

Keyword(s):

Ex Vivo ◽

Macrophage Polarization ◽

Dependent Manner ◽

Oxygen Species ◽

Superoxide Anions ◽

Wild Type ◽

Macrophage Population ◽

The Family ◽

High Level

The family of NADPH oxidases represents an important source of reactive oxygen species (ROS) within the cell. Nox4 is a special member of this family as it constitutively produces H2O2 and its loss promotes inflammation. A major cellular component of inflammation is the macrophage population, which can be divided into several subpopulations depending on their phenotype, with proinflammatory M(LPS+IFNγ) and wound-healing M(IL4+IL13) macrophages being extremes of the functional spectrum. Whether Nox4 is expressed in macrophages is discussed controversially. Here, we show that macrophages besides a high level of Nox2 indeed express Nox4. As Nox4 contributes to differentiation of many cells, we hypothesize that Nox4 plays a role in determining the polarization and the phenotype of macrophages. In bone marrow-derived monocytes, ex vivo treatment with LPS/IFNγ or IL4/IL13 results in polarization of the cells into M(LPS+IFNγ) or M(IL4+IL13) macrophages, respectively. In this ex vivo setting, Nox4 deficiency reduces M(IL4+IL13) polarization and forces M(LPS+IFNγ). Nox4-/- M(LPS+IFNγ)-polarized macrophages express more Nox2 and produce more superoxide anions than wild type M(LPS+IFNγ)-polarized macrophages. Mechanistically, Nox4 deficiency reduces STAT6 activation and promotes NFκB activity, with the latter being responsible for the higher level of Nox2 in Nox4-deficient M(LPS+IFNγ)-polarized macrophages. According to those findings, in vivo, in a murine inflammation-driven fibrosarcoma model, Nox4 deficiency forces the expression of proinflammatory genes and cytokines, accompanied by an increase in the number of proinflammatory Ly6C+ macrophages in the tumors. Collectively, the data obtained in this study suggest an anti-inflammatory role for Nox4 in macrophages. Nox4 deficiency results in less M(IL4+IL13) polarization and suppression of NFκB activity in monocytes.

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Peptidic degron for IMiD-induced degradation of heterologous proteins

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1818109116 ◽

2019 ◽

Vol 116 (7) ◽

pp. 2539-2544 ◽

Cited By ~ 9

Author(s):

Vidyasagar Koduri ◽

Samuel K. McBrayer ◽

Ella Liberzon ◽

Adam C. Wang ◽

Kimberly J. Briggs ◽

...

Keyword(s):

Protein Function ◽

Cultured Cells ◽

Ex Vivo ◽

Ease Of Use ◽

Dependent Manner ◽

Heterologous Proteins ◽

Ubiquitin Ligase Complex ◽

Dose Dependent ◽

Current Systems

Current systems for modulating the abundance of proteins of interest in living cells are powerful tools for studying protein function but differ in terms of their complexity and ease of use. Moreover, no one system is ideal for all applications, and the best system for a given protein of interest must often be determined empirically. The thalidomide-like molecules (collectively called the IMiDs) bind to the ubiquitously expressed cereblon ubiquitin ligase complex and alter its substrate specificity such that it targets the IKZF1 and IKZF3 lymphocyte transcription factors for destruction. Here, we mapped the minimal IMiD-responsive IKZF3 degron and show that this peptidic degron can be used to target heterologous proteins for destruction with IMiDs in a time- and dose-dependent manner in cultured cells grown ex vivo or in vivo.

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Enhancement in Site-Specific Delivery of Carvacrol against Methicillin Resistant Staphylococcus aureus Induced Skin Infections Using Enzyme Responsive Nanoparticles: A Proof of Concept Study

Pharmaceutics ◽

10.3390/pharmaceutics11110606 ◽

2019 ◽

Vol 11 (11) ◽

pp. 606 ◽

Cited By ~ 8

Author(s):

Maria Mir ◽

Naveed Ahmed ◽

Andi Dian Permana ◽

Aoife Maria Rodgers ◽

Ryan F. Donnelly ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Ex Vivo ◽

Infection Model ◽

Skin Infections ◽

Site Specific ◽

Methicillin Resistant ◽

Hydrogel Matrix ◽

Skin Retention

Methicillin resistant Staphylococcus aureus (MRSA) induced skin infections have become a challenging problem due to the escalating antibiotic resistance. Carvacrol (CAR) has been reported to be effective against MRSA. However, due to its characteristics, CAR exhibits low skin retention. In this study, CAR was formulated into site-specific nanoparticle (NPs) delivery system using poly(ε-caprolactone) (PCL), following incorporation into a hydrogel matrix to facilitate dermal delivery. The release study exhibited significantly higher release of CAR from PCL NPs in the presence of bacterial lipase, highlighting its potential for differential delivery. Moreover, encapsulation of CAR in PCL NPs resulted in a two-fold increase in its anti-MRSA activity. Dermatokinetic studies revealed that the NPs loaded hydrogel was able to enhance skin retention of CAR after 24 h (83.29 ± 3.15%), compared to free CAR-loaded hydrogel (0.85 ± 0.14%). Importantly, this novel approach exhibited effective antimicrobial activity in an ex-vivo skin infection model. Hence, these findings have proven the concept that the loading of CAR into a responsive NPs system can lead to sustained antimicrobial effect at the desired site, and may provide a novel effective approach for treatment of MRSA induced skin infections. However, further studies must be conducted to investigate in-vivo efficacy of the developed system in an appropriate infection model.

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