scholarly journals Bis-Benzimidazole Hits against Naegleria fowleri Discovered with New High-Throughput Screens

2015 ◽  
Vol 59 (4) ◽  
pp. 2037-2044 ◽  
Author(s):  
Christopher A. Rice ◽  
Beatrice L. Colon ◽  
Mehmet Alp ◽  
Hakan Göker ◽  
David W. Boykin ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
High Throughput ◽  
Lead Optimization ◽  
New Drugs ◽  
Naegleria Fowleri ◽  
Onset Of Action ◽  
Content Type ◽  
Nægleria Fowleri

ABSTRACTNaegleria fowleriis a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two newin vitroassays suitable for medium- or high-throughput drug discovery and used these forN. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono- and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC50) of 177 nM. Similarly, we identified 10 additional analogues with IC50s of <1 μM, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono- and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections withN. fowleri.

scholarly journals EdU incorporation to assess cell proliferation and drug susceptibility for the brain-eating amoeba, Naegleria fowleri

2021 ◽  
Author(s):  
Emma V Troth ◽  
Dennis E Kyle
Keyword(s):  
Cell Proliferation ◽  
Drug Discovery ◽  
Quantitative Methods ◽  
Click Reaction ◽  
New Drugs ◽  
Alternative Methods ◽  
Naegleria Fowleri ◽  
Screening Assay ◽  
Nægleria Fowleri

Naegleria fowleri is a pathogenic free-living amoeba that is commonly found in warm, freshwater and can cause a rapidly fulminant disease known as primary amoebic meningoencephalitis (PAM). New drugs are urgently needed to treat PAM, as the fatality rate is >97%. Until recently, few advances have been made in the discovery of new drugs for N. fowleri and one drawback is the lack of validated tools and methods to enhance drug discovery and diagnostics research. In this study we aimed to validate alternative methods to assess cell proliferation that are commonly used for other cell types and develop a novel drug screening assay to evaluate drug efficacy on N. fowleri replication. EdU (5-ethynyl-2´-deoxyuridine) is a pyrimidine analog of thymidine that can be used as a quantitative endpoint for cell proliferation. EdU incorporation is detected via a copper catalyzed click reaction with an Alexa Fluor linked azide. EdU incorporation in replicating N. fowleri was validated using fluorescence microscopy and quantitative methods for assessing EdU incorporation were developed by using an imaging flow cytometer. Currently used PAM therapeutics inhibited N. fowleri replication and EdU incorporation in vitro. EdA (5'ethynyl-2'-deoxyadenosine), an adenine analog, also was incorporated by N. fowleri, but was more cytotoxic than EdU. In summary, EdU incorporation could be used as a complimentary method for drug discovery for these neglected pathogens.

scholarly journals Synergistic Activities of Azithromycin and Amphotericin B against Naegleria fowleri In Vitro and in a Mouse Model of Primary Amebic Meningoencephalitis

2006 ◽  
Vol 51 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Shannon M. Soltow ◽  
George M. Brenner
Keyword(s):  
Central Nervous System ◽  
Mouse Model ◽  
Amphotericin B ◽  
Fixed Combination ◽  
Central Nervous System Infection ◽  
Naegleria Fowleri ◽  
Combined Use ◽  
Nægleria Fowleri ◽  
Primary Amebic Meningoencephalitis

ABSTRACT Naegleria fowleri is responsible for producing a rapidly fatal central nervous system infection known as primary amebic meningoencephalitis (PAM). To date, amphotericin B, an antifungal agent, is the only agent with established clinical efficacy in the treatment of PAM. However, amphotericin B is not always successful in treating PAM and is associated with severe adverse effects. We previously found azithromycin to be more effective than amphotericin B in a mouse model of PAM. We therefore investigated the combination of amphotericin B and azithromycin in vitro and in a mouse model of PAM. For the in vitro studies, 50% inhibitory concentrations were calculated for each drug alone and for the drugs in fixed combination ratios of 1:1, 3:1, and 1:3. We found amphotericin B and azithromycin to be synergistic at all three of the fixed combination ratios. In our mouse model of PAM, a combination of amphotericin B (2.5 mg/kg of body weight) and azithromycin (25 mg/kg) protected 100% of the mice, whereas amphotericin B alone (2.5 mg/kg) protected only 27% of mice and azithromycin alone (25 mg/kg) protected 40% of mice. This study indicates that amphotericin B and azithromycin are synergistic against the Lee strain of N. fowleri, suggesting that the combined use of these agents may be beneficial in treating PAM.

scholarly journals Naegleria fowleri: Pathogenesis, Diagnosis, and Treatment Options

2015 ◽  
Vol 59 (11) ◽  
pp. 6677-6681 ◽  
Author(s):  
Eddie Grace ◽  
Scott Asbill ◽  
Kris Virga
Keyword(s):  
Case Reports ◽  
Treatment Options ◽  
Clinical Manifestations ◽  
Naegleria Fowleri ◽  
Content Type ◽  
High Profile ◽  
Free Living Amoeba ◽  
Nægleria Fowleri ◽  
Amoebic Meningoencephalitis

ABSTRACTNaegleria fowlerihas generated tremendous media attention over the last 5 years due to several high-profile cases. Several of these cases were followed very closely by the general public.N. fowleriis a eukaryotic, free-living amoeba belonging to the phylum Percolozoa.Naegleriaamoebae are ubiquitous in the environment, being found in soil and bodies of freshwater, and feed on bacteria found in those locations. WhileN. fowleriinfection appears to be quite rare compared to other diseases, the clinical manifestations of primary amoebic meningoencephalitis are devastating and nearly always fatal. Due to the rarity ofN. fowleriinfections in humans, there are no clinical trials to date that assess the efficacy of one treatment regimen over another. Most of the information regarding medication efficacy is based on either case reports orin vitrostudies. This review will discuss the pathogenesis, diagnosis, pharmacotherapy, and prevention ofN. fowleriinfections in humans, including a brief review of all survivor cases in North America.

Efficacy of LY233053, a competitive glutamate antagonist, in experimental central nervous system ischemia

1992 ◽  
Vol 76 (1) ◽  
pp. 106-110 ◽  
Author(s):  
Kenneth P. Madden ◽  
Wayne M. Clark ◽  
Abha Kochhar ◽  
Justin A. Zivin
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Side Effects ◽  
Excitatory Amino Acids ◽  
Neurological Damage ◽  
Content Type ◽  
Glutamate Antagonist ◽  
Fine Print

✓ Antagonists of excitatory amino acids appear to serve a neuroprotective role during ischemic conditions in a variety of in vivo and in vitro models. The usefulness of such agents in the clinical setting, however, may be limited by poor central nervous system (CNS) entry and intolerable side effects. The authors report high efficacy in reducing neurological damage and relatively limited side effects of LY233053, a novel competitive glutamate antagonist, in two models of experimental CNS ischemia in the rabbit.

Immunotoxins and central nervous system neoplasia

1992 ◽  
Vol 76 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Walter A. Hall ◽  
Øystein Fodstad
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Malignant Disease ◽  
High Specificity ◽  
Intrathecal Administration ◽  
Treatment Modalities ◽  
Content Type ◽  
Toxic Agents ◽  
Cns Malignancy

✓ The poor prognosis associated with central nervous system (CNS) malignancy has led investigators to seek new, innovative treatment modalities. Immunotoxins, carrier molecules linked to toxic agents, combine high specificity for tumor-associated antigens with extreme potency. The rationale for both the development of these compounds and for their application to CNS neoplasia is explained. This report discusses the design and construction of immunoconjugates, using toxins that differ in their mechanism of action bound to ligands directed against various antigens. A comparison is made between the in vitro efficacy of standard chemotherapy and immunotoxins in glioblastoma- and medulloblastoma-derived cell lines. A review is included of the results of experiments in animals with leptomeningeal neoplasia, where prolongation of survival following intrathecal administration of immunotoxins has been reported. The obstacles encountered in clinical trials with other types of cancer are addressed and approaches to optimize the use of these novel agents in the context of treating malignant disease of the CNS are suggested.

scholarly journals EdU incorporation to assess cell proliferation and drug susceptibility in Naegleria fowleri.

2021 ◽  
Author(s):  
Emma V. Troth ◽  
Dennis E. Kyle
Keyword(s):  
Cell Proliferation ◽  
Drug Discovery ◽  
Quantitative Methods ◽  
Click Reaction ◽  
New Drugs ◽  
Alternative Methods ◽  
Naegleria Fowleri ◽  
Screening Assay ◽  
Nægleria Fowleri

Naegleria fowleri is a pathogenic free-living amoeba that is commonly found in warm, freshwater and can cause a rapidly fulminant disease known as primary amoebic meningoencephalitis (PAM). New drugs are urgently needed to treat PAM, as the fatality rate is >97%. Until recently, few advances have been made in the discovery of new drugs for N. fowleri and one drawback is the lack of validated tools and methods to enhance drug discovery and diagnostics research. In this study we aimed to validate alternative methods to assess cell proliferation that are commonly used for other cell types and develop a novel drug screening assay to evaluate drug efficacy on N. fowleri replication. EdU (5-ethynyl-2’-deoxyuridine) is a pyrimidine analog of thymidine that can be used as a quantitative endpoint for cell proliferation. EdU incorporation is detected via a copper catalyzed click reaction with an Alexa Fluor linked azide. EdU incorporation in replicating N. fowleri was validated using fluorescence microscopy and quantitative methods for assessing EdU incorporation were developed by using an imaging flow cytometer. Currently used PAM therapeutics inhibited N. fowleri replication and EdU incorporation in vitro. EdA (5’ethynyl-2’-deoxyadenosine), an adenine analog, also was incorporated by N. fowleri, but was more cytotoxic than EdU. In summary, EdU incorporation could be used as a complimentary method for drug discovery for these neglected pathogens.

Insulin and insulin-like growth factors in central nervous system tumors

1992 ◽  
Vol 77 (3) ◽  
pp. 445-450 ◽  
Author(s):  
Roberta P. Glick ◽  
Terry G. Unterman ◽  
Mary Van der Woude ◽  
Lisa Zollner Blaydes
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Growth Factor ◽  
Tumor Cell ◽  
Cns Tumors ◽  
Insulin Like Growth Factor ◽  
Content Type ◽  
Igf I ◽  
Fine Print

✓ The authors have previously reported the presence of insulin-like growth factor (IGF) receptors in central nervous system (CNS) tumors and the production of IGF's and their binding proteins by CNS tumors in situ. This study was designed to investigate whether CNS tumor cells are capable of autocrine secretion of IGF-I and IGF-II in vitro. Production of IGF's was studied by specific radioimmunoassay of tumor-cell-conditioned serum-free media from 34 CNS tumors: 12 gliomas, 12 meningiomas, and 10 miscellaneous tumors. Normal human serum and cerebrospinal fluid served as controls. Insulin-like growth factor I was detected in five of 12 meningiomas but in none of the gliomas studied. In contrast, IGF-II was detected in four of 12 gliomas and in six of 11 meningiomas studied. Four miscellaneous tumors produced IGF-I and/or IGF-II. These results suggest that CNS tumors differentially produce IGF-I and IGF-II in vitro. Preferential production of IGF's may be an important marker of the tumor-cell differentiation or malignancy and may be useful as a clinical diagnostic tool. These results add further support to the concept that IGF's may play a role in the regulation of the behavior of CNS tumors.

scholarly journals The Antidepressant Sertraline Provides a Promising Therapeutic Option for Neurotropic Cryptococcal Infections

2012 ◽  
Vol 56 (7) ◽  
pp. 3758-3766 ◽  
Author(s):  
Bing Zhai ◽  
Cheng Wu ◽  
Linqi Wang ◽  
Matthew S. Sachs ◽  
Xiaorong Lin
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Fungal Infections ◽  
Therapeutic Option ◽  
Susceptibility Gene ◽  
Content Type ◽  
Fungal Burden ◽  
Cell Extracts ◽  
Cns Penetration

ABSTRACTTherapeutic treatment for systemic mycoses is severely hampered by the extremely limited number of antifungals. The difficulty of treatment of fungal infections in the central nervous system is further compounded by the poor central nervous system (CNS) penetration of most antifungals due to the blood-brain barrier. Only a few fungistatic azole drugs, such as fluconazole, show reasonable CNS penetration. Here we demonstrate that sertraline (Zoloft), the most frequently prescribed antidepressant, displays potent antifungal activity againstCryptococcus neoformans, the major causative agent of fungal meningitis. Inin vitroassays, this neurotropic drug is fungicidal to all naturalCryptococcusisolates tested at clinically relevant concentrations. Furthermore, sertraline interacts synergistically or additively with fluconazole againstCryptococcus. Importantly, consistent with ourin vitroobservations, sertraline used alone reduces the brain fungal burden at an efficacy comparable to that of fluconazole in a murine model of systemic cryptococcosis. It works synergistically with fluconazole in reducing the fungal burden in brain, kidney, and spleen. In contrast to its potency againstCryptococcus, sertraline is less effective against strains ofCandidaspecies and its interactions with fluconazole againstCandidastrains are often antagonistic. Therefore, our data suggest the unique application of sertraline against cryptococcosis. To understand the antifungal mechanisms of sertraline, we screened a whole-genome deletion collection ofSaccharomyces cerevisiaefor altered sertraline susceptibility. Gene ontology analyses of selected mutations suggest that sertraline perturbs translation.In vitrotranslation assays using fungal cell extracts show that sertraline inhibits protein synthesis. Taken together, our findings indicate the potential of adopting this antidepressant in treating cryptococcal meningitis.

scholarly journals The Orotomide Olorofim Is Efficacious in an Experimental Model of Central Nervous System Coccidioidomycosis

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Rosie Jaramillo ◽  
Marcos Olivo ◽  
Michael Birch ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Oral Therapy ◽  
Vehicle Control ◽  
Coccidioides Immitis ◽  
Central Nervous System Infections ◽  
Content Type ◽  
Highly Active

ABSTRACT Olorofim (formerly F901318) is an advanced analog of the orotomide class that inhibits fungal pyrimidine biosynthesis. We evaluated the in vitro and in vivo activities of olorofim against Coccidioides species. In vitro activity was assessed against 59 clinical Coccidioides isolates. Central nervous system infections were established in mice via intracranial inoculation with Coccidioides immitis arthroconidia. Oral therapy began 48 h postinoculation and consisted of vehicle control, olorofim daily doses of 20 mg/kg (6.67 mg/kg three times daily or 10 mg/kg twice daily) or 40 mg/kg (13.3 mg/kg three times daily or 20 mg/kg twice daily), or fluconazole (25 mg/kg twice daily). Treatment continued for 7 and 14 days in the fungal burden and survival arms, respectively. Fungal burdens were assessed by CFU counts in brains. Olorofim demonstrated potent in vitro activity (MIC range, ≤0.008 to 0.06 μg/ml). Survival was significantly enhanced in mice treated with olorofim. Reductions in brain tissue fungal burdens were also observed on day 9 in the olorofim-treated groups. Improvements in survival and reductions in fungal burdens also occurred with fluconazole. More frequent dosing of olorofim was associated with enhanced survival and greater reductions in fungal burdens. In the group treated with 13.3 mg/kg olorofim three times daily, fungal burdens remained low on day 30 (15 days after treatment was stopped), with undetectable levels in 7 of 10 mice. In contrast, fungal burdens rebounded in all other groups after therapy stopped. Olorofim was highly active in vitro and in vivo against Coccidioides. These results demonstrate that olorofim may have a role in the treatment of coccidioidomycosis.

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