Enrofloxacin is able to control Toxoplasma gondii infection in both in vitro and in vivo experimental models

The apicomplexan parasite Toxoplasma gondii is the causative agent of toxoplasmosis, a globally distributed infection with severe clinical consequences for immunocompromised individuals and developing fetuses. There are few available treatments, and these are associated with potentially severe adverse effects. Marinopyrrole A, a compound discovered in a marine Streptomyces species, has previously been found to exhibit potent antimicrobial activity, prompting our interest in exploring efficacy against Toxoplasma gondii . We found that marinopyrrole A was a highly potent anti- Toxoplasma molecule, with an in vitro 50% maximal inhibitory concentration (IC 50 ) of 0.31 μM corresponding to a higher potency than that of the current standard of care (pyrimethamine); however, addition of 20% serum led to abrogation of potency, and toxicity to human cell lines was observed. Yet, application of marinopyrrole A to an in vivo lethal acute infection model facilitated significantly enhanced survival at doses of 5, 10, and 20 mg/kg. We then tested a series of marinopyrrole A analogs—RL002, RL003, and RL125—demonstrating significantly increased potency in vitro , with IC 50 values ranging from 0.09-0.17 μM (3.6-6.8X increase relative to pyrimethamine). No detectable cytotoxicity was observed up to 50 μM in human foreskin fibroblasts, with cytotoxicity in HepG2 cells ranging from ∼28-50 μM, corresponding to >200X selectivity for parasites over host cells. All analogs additionally showed reduced sensitivity to serum. Further, RL003 potently inhibited in vitro -generated bradyzoites at 0.245 μM. Taken together, these data support further development of marinopyrrole A analogs as promising anti- Toxoplasma molecules to further combat this prevalent infection.

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Diacylglycerol kinase ζ regulates microbial recognition and host resistance to Toxoplasma gondii

Journal of Experimental Medicine ◽

10.1084/jem.20061856 ◽

2007 ◽

Vol 204 (4) ◽

pp. 781-792 ◽

Cited By ~ 45

Author(s):

Cheng-Hu Liu ◽

Fabiana S. Machado ◽

Rishu Guo ◽

Kim E. Nichols ◽

A. Wesley Burks ◽

...

Keyword(s):

Innate Immunity ◽

Toxoplasma Gondii ◽

Second Messengers ◽

Endotoxin Shock ◽

Microbial Infection ◽

Surface Receptors ◽

Toxoplasma Gondii Infection ◽

Factor Α

Mammalian Toll-like receptors (TLRs) recognize microbial pathogen-associated molecular patterns and are critical for innate immunity against microbial infection. Diacylglycerol (DAG) kinases (DGKs) regulate the intracellular levels of two important second messengers involved in signaling from many surface receptors by converting DAG to phosphatidic acid (PA). We demonstrate that the ζ isoform of the DGK family (DGKζ) is expressed in macrophages (Mφ) and dendritic cells. DGKζ deficiency results in impaired interleukin (IL) 12 and tumor necrosis factor α production following TLR stimulation in vitro and in vivo, increased resistance to endotoxin shock, and enhanced susceptibility to Toxoplasma gondii infection. We further show that DGKζ negatively controls the phosphatidylinositol 3–kinase (PI3K)–Akt pathway and that inhibition of PI3K activity or treatment with PA can restore lipopolysaccharide-induced IL-12 production by DGKζ-deficient Mφ. Collectively, our data provide the first genetic evidence that an enzyme involved in DAG/PA metabolism plays an important role in innate immunity and indicate that DGKζ promotes TLR responses via a pathway involving inhibition of PI3K.

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Evaluation of the anti-Toxoplasma gondii Activity of Hederagenin in vitro and in vivo

The Korean Journal of Parasitology ◽

10.3347/kjp.2021.59.3.297 ◽

2021 ◽

Vol 59 (3) ◽

pp. 297-301

Author(s):

Run-Hui Zhang ◽

Runhao Jin ◽

Hao Deng ◽

Qing-Kun Shen ◽

Zhe-Shan Quan ◽

...

Keyword(s):

Food Safety ◽

Toxoplasma Gondii ◽

Biochemical Parameters ◽

Animal Husbandry ◽

Selectivity Index ◽

In Vivo Experiments ◽

Low Cytotoxicity ◽

Toxoplasma Gondii Infection

Toxoplasma gondii infection is widespread worldwide, not only posing a serious threat to human food safety and animal husbandry, but also endangering human health. The selectivity index was employed to measure anti-T. gondii activity. Hederagenin (HE) exhibited potent anti-T. gondii activity and low cytotoxicity. For this reason, HE was selected for in vivo experiments. HE showed 64.8%±13.1% inhibition for peritoneal tachyzoites in mice, higher than spiramycin 56.8%±6.0%. Biochemical parameters such as alanine aminotransferase, aspartate aminotransferase, glutathione, and malondialdehyde, illustrated that HE was a good inhibitor of T. gondii in vivo. This compound was also effective in relieving T. gondii-induced liver damage. Collectively, it was demonstrated that HE had potential as an anti-T. gondii agent.

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Neutralization of a Low Molecular Weight Heparin (LHN-1) and Conventional Heparin by Protamine Sulfate in Rats

Thrombosis and Haemostasis ◽

10.1055/s-0038-1661675 ◽

1986 ◽

Vol 56 (03) ◽

pp. 318-322 ◽

Cited By ~ 18

Author(s):

V Diness ◽

P B Østergaard

Keyword(s):

Molecular Weight ◽

Low Molecular Weight Heparin ◽

Thrombus Formation ◽

Experimental Models ◽

Protamine Sulfate ◽

Low Molecular Weight ◽

Antithrombotic Effect ◽

Higher Doses

SummaryThe neutralization of a low molecular weight heparin (LHN-1) and conventional heparin (CH) by protamine sulfate has been studied in vitro and in vivo. In vitro, the APTT activity of CH was completely neutralized in parallel with the anti-Xa activity. The APTT activity of LHN-1 was almost completely neutralized in a way similar to the APTT activity of CH, whereas the anti-Xa activity of LHN-1 was only partially neutralized.In vivo, CH 3 mg/kg and LHN-1 7.2 mg/kg was given intravenously in rats. The APTT and anti-Xa activities, after neutralization by protamine sulfate in vivo, were similar to the results in vitro. In CH treated rats no haemorrhagic effect in the rat tail bleeding test and no antithrombotic effect in the rat stasis model was found at a protamine sulfate to heparin ratio of about 1, which neutralized APTT and anti-Xa activities. In LHN-1 treated rats the haemorrhagic effect was neutralized when APTT was close to normal whereas higher doses of protamine sulfate were required for neutralization of the antithrombotic effect. This probably reflects the fact that in most experimental models higher doses of heparin are needed to induce bleeding than to prevent thrombus formation. Our results demonstrate that even if complete neutralization of APTT and anti-Xa activities were not seen in LHN-1 treated rats, the in vivo effects of LHN-1 could be neutralized as efficiently as those of conventional heparin. The large fall in blood pressure caused by high doses of protamine sulfate alone was prevented by the prior injection of LHN-1.

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Antimicrobial peptides for the treatment of pulmonary tuberculosis, allies or foes?

Current Pharmaceutical Design ◽

10.2174/1381612824666180327162357 ◽

2018 ◽

Vol 24 (10) ◽

pp. 1138-1147

Author(s):

Bruno Rivas-Santiago ◽

Flor Torres-Juarez

Keyword(s):

Pulmonary Tuberculosis ◽

Antimicrobial Peptides ◽

Experimental Models ◽

New Drugs ◽

World Health ◽

Public Health Issue ◽

Health Organization ◽

Drug Resistant Strains

Tuberculosis is an ancient disease that has become a serious public health issue in recent years, although increasing incidence has been controlled, deaths caused by Mycobacterium tuberculosis have been accentuated due to the emerging of multi-drug resistant strains and the comorbidity with diabetes mellitus and HIV. This situation is threatening the goals of World Health Organization (WHO) to eradicate tuberculosis in 2035. WHO has called for the creation of new drugs as an alternative for the treatment of pulmonary tuberculosis, among the plausible molecules that can be used are the Antimicrobial Peptides (AMPs). These peptides have demonstrated remarkable efficacy to kill mycobacteria in vitro and in vivo in experimental models, nevertheless, these peptides not only have antimicrobial activity but also have a wide variety of functions such as angiogenesis, wound healing, immunomodulation and other well-described roles into the human physiology. Therapeutic strategies for tuberculosis using AMPs must be well thought prior to their clinical use; evaluating comorbidities, family history and risk factors to other diseases, since the wide function of AMPs, they could lead to collateral undesirable effects.

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Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses

Current Topics in Medicinal Chemistry ◽

10.2174/1568026618666180410125850 ◽

2018 ◽

Vol 18 (4) ◽

pp. 246-255 ◽

Cited By ~ 1

Author(s):

Lara Termini ◽

Enrique Boccardo

Keyword(s):

Three Dimensional ◽

Cell Types ◽

Experimental Models ◽

Biological Research ◽

Specific Gene ◽

Specific Cell ◽

Organotypic Cultures ◽

Skin Physiology

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.

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Experimental Models of Hepatocellular Carcinoma—A Preclinical Perspective

Cancers ◽

10.3390/cancers13153651 ◽

2021 ◽

Vol 13 (15) ◽

pp. 3651

Author(s):

Alexandru Blidisel ◽

Iasmina Marcovici ◽

Dorina Coricovac ◽

Florin Hut ◽

Cristina Adriana Dehelean ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Molecular Mechanisms ◽

Prediction Models ◽

3D Models ◽

Experimental Models ◽

Health Concern ◽

Liver Carcinoma ◽

Tumor Type

Hepatocellular carcinoma (HCC), the most frequent form of primary liver carcinoma, is a heterogenous and complex tumor type with increased incidence, poor prognosis, and high mortality. The actual therapeutic arsenal is narrow and poorly effective, rendering this disease a global health concern. Although considerable progress has been made in terms of understanding the pathogenesis, molecular mechanisms, genetics, and therapeutical approaches, several facets of human HCC remain undiscovered. A valuable and prompt approach to acquire further knowledge about the unrevealed aspects of HCC and novel therapeutic candidates is represented by the application of experimental models. Experimental models (in vivo and in vitro 2D and 3D models) are considered reliable tools to gather data for clinical usability. This review offers an overview of the currently available preclinical models frequently applied for the study of hepatocellular carcinoma in terms of initiation, development, and progression, as well as for the discovery of efficient treatments, highlighting the advantages and the limitations of each model. Furthermore, we also focus on the role played by computational studies (in silico models and artificial intelligence-based prediction models) as promising novel tools in liver cancer research.

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Current Status of Putative Animal Sources of SARS-CoV-2 Infection in Humans: Wildlife, Domestic Animals and Pets

Microorganisms ◽

10.3390/microorganisms9040868 ◽

2021 ◽

Vol 9 (4) ◽

pp. 868

Author(s):

Max Maurin ◽

Florence Fenollar ◽

Oleg Mediannikov ◽

Bernard Davoust ◽

Christian Devaux ◽

...

Keyword(s):

Animal Species ◽

Biological Properties ◽

Experimental Models ◽

Current Data ◽

The Body ◽

Receptor Expression ◽

Current Status ◽

Susceptible Animal

SARS-CoV-2 is currently considered to have emerged from a bat coronavirus reservoir. However, the real natural cycle of this virus remains to be elucidated. Moreover, the COVID-19 pandemic has led to novel opportunities for SARS-CoV-2 transmission between humans and susceptible animal species. In silico and in vitro evaluation of the interactions between the SARS-CoV-2 spike protein and eucaryotic angiotensin-converting enzyme 2 (ACE2) receptor have tentatively predicted susceptibility to SARS-CoV-2 infection of several animal species. Although useful, these data do not always correlate with in vivo data obtained in experimental models or during natural infections. Other host biological properties may intervene such as the body temperature, level of receptor expression, co-receptor, restriction factors, and genetic background. The spread of SARS-CoV-2 also depends on the extent and duration of viral shedding in the infected host as well as population density and behaviour (group living and grooming). Overall, current data indicate that the most at-risk interactions between humans and animals for COVID-19 infection are those involving certain mustelids (such as minks and ferrets), rodents (such as hamsters), lagomorphs (especially rabbits), and felines (including cats). Therefore, special attention should be paid to the risk of SARS-CoV-2 infection associated with pets.

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