scholarly journals Pharmacological Modulation of Serotonin Levels in Zebrafish Larvae: Lessons for Identifying Environmental Neurotoxicants Targeting the Serotonergic System

Toxics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 118
Author(s):  
Melissa Faria ◽  
Eva Prats ◽  
Marina Bellot ◽  
Cristian Gomez-Canela ◽  
Demetrio Raldúa

This study examines the effects of acute pharmacological modulation of the serotonergic system over zebrafish larvae’s cognitive, basic, and defense locomotor behaviors, using a medium to high throughput screening assay. Furthermore, the relationship between behavior, enzyme activity related to neurotransmitter metabolism, neurotransmitter levels, and gene expression was also determined. Modulation of larvae serotonergic system was accomplished by 24 h exposure to single and opposite pharmacodynamics co-exposure to three model psychopharmaceuticals with antagonistic and agonistic serotonin signaling properties: 2.5 mM 4-Chloro-DL-phenylalanine (PCPA) and 5 µM deprenyl and 0.5 µM fluoxetine, respectively. Similar behavioral outcome was observed for deprenyl and fluoxetine, which was reflected as hypolocomotion, decrease in larvae defensive responses, and cognitive impairment. Contrarily, PCPA induced hyperlocomotion and increase in larvae escape response. Deprenyl exposure effects were more pronounced at a lower level of organization than fluoxetine, with complete inhibition of monoamine oxidase (MAO) activity, dramatic increase of 5-HT and dopamine (DA) levels, and downregulation of serotonin synthesis and transporter genes. PCPA showed mainly effects over serotonin and dopamine’s main degradation metabolites. Finally, co-exposure between agonistic and antagonist serotonin signaling drugs reviled full recovery of zebrafish impaired locomotor and defense responses, 5-HT synthesis gene expression, and partial recovery of 5-HT levels. The findings of this study suggest that zebrafish larvae can be highly sensitive and a useful vertebrate model for short-term exposure to serotonin signaling changes.

2018 ◽  
Vol 20 (9) ◽  
pp. 804-819 ◽  
Author(s):  
Mohamed Boudjelal ◽  
Ana Maria Ruiz-Avendano ◽  
Gonzalo Colmenarejo ◽  
Sergio A. Senar-Sancho ◽  
Ashley Barnes ◽  
...  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sadaf Kalsum ◽  
Blanka Andersson ◽  
Jyotirmoy Das ◽  
Thomas Schön ◽  
Maria Lerm

Abstract Background Efficient high-throughput drug screening assays are necessary to enable the discovery of new anti-mycobacterial drugs. The purpose of our work was to develop and validate an assay based on live-cell imaging which can monitor the growth of two distinct phenotypes of Mycobacterium tuberculosis and to test their susceptibility to commonly used TB drugs. Results Both planktonic and cording phenotypes were successfully monitored as fluorescent objects using the live-cell imaging system IncuCyte S3, allowing collection of data describing distinct characteristics of aggregate size and growth. The quantification of changes in total area of aggregates was used to define IC50 and MIC values of selected TB drugs which revealed that the cording phenotype grew more rapidly and displayed a higher susceptibility to rifampicin. In checkerboard approach, testing pair-wise combinations of sub-inhibitory concentrations of drugs, rifampicin, linezolid and pretomanid demonstrated superior growth inhibition of cording phenotype. Conclusions Our results emphasize the efficiency of using automated live-cell imaging and its potential in high-throughput whole-cell screening to evaluate existing and search for novel antimycobacterial drugs.


2021 ◽  
pp. 247255522110006
Author(s):  
Lesley-Anne Pearson ◽  
Charlotte J. Green ◽  
De Lin ◽  
Alain-Pierre Petit ◽  
David W. Gray ◽  
...  

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) represents a significant threat to human health. Despite its similarity to related coronaviruses, there are currently no specific treatments for COVID-19 infection, and therefore there is an urgent need to develop therapies for this and future coronavirus outbreaks. Formation of the cap at the 5′ end of viral RNA has been shown to help coronaviruses evade host defenses. Nonstructural protein 14 (nsp14) is responsible for N7-methylation of the cap guanosine in coronaviruses. This enzyme is highly conserved among coronaviruses and is a bifunctional protein with both N7-methyltransferase and 3′-5′ exonuclease activities that distinguish nsp14 from its human equivalent. Mutational analysis of SARS-CoV nsp14 highlighted its role in viral replication and translation efficiency of the viral genome. In this paper, we describe the characterization and development of a high-throughput assay for nsp14 utilizing RapidFire technology. The assay has been used to screen a library of 1771 Food and Drug Administration (FDA)-approved drugs. From this, we have validated nitazoxanide as a selective inhibitor of the methyltransferase activity of nsp14. Although modestly active, this compound could serve as a starting point for further optimization.


2021 ◽  
Vol 22 (3) ◽  
pp. 1231
Author(s):  
Ihab M. Abdallah ◽  
Kamal M. Al-Shami ◽  
Euitaek Yang ◽  
Amal Kaddoumi

In Alzheimer’s disease (AD), several studies have reported blood-brain barrier (BBB) breakdown with compromised function. P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are transport proteins localized at the BBB luminal membrane and play an important role in the clearance of amyloid-β (Aβ). The purpose of this study was to investigate the effect of pharmacological inhibition of Aβ efflux transporters on BBB function and Aβ accumulation and related pathology. Recently, we have developed an in vitro high-throughput screening assay to screen for compounds that modulate the integrity of a cell-based BBB model, which identified elacridar as a disruptor of the monolayer integrity. Elacridar, an investigational compound known for its P-gp and BCRP inhibitory effect and widely used in cancer research. Therefore, it was used as a model compound for further evaluation in a mouse model of AD, namely TgSwDI. TgSwDI mouse is also used as a model for cerebral amyloid angiopathy (CAA). Results showed that P-gp and BCRP inhibition by elacridar disrupted the BBB integrity as measured by increased IgG extravasation and reduced expression of tight junction proteins, increased amyloid deposition due to P-gp, and BCRP downregulation and receptor for advanced glycation end products (RAGE) upregulation, increased CAA and astrogliosis. Further studies revealed the effect was mediated by activation of NF-κB pathway. In conclusion, results suggest that BBB disruption by inhibiting P-gp and BCRP exacerbates AD pathology in a mouse model of AD, and indicate that therapeutic drugs that inhibit P-gp and BCRP could increase the risk for AD.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 767-768
Author(s):  
Vijay Varma ◽  
Youjin Wang ◽  
Yang An ◽  
Sudhir Varma ◽  
Murat Bilgel ◽  
...  

Abstract While Alzheimer’s disease (AD) and vascular dementia (VaD) may be accelerated by hypercholesterolemia, the mechanisms underlying this association is unclear. Using a novel, 3-step study design we examined the role of cholesterol catabolism in dementia by testing whether 1) the synthesis of the primary cholesterol breakdown products (bile acids (BA)) were associated with neuroimaging markers of dementia; 2) pharmacological modulation of BAs alters dementia risk; and 3) brain BA concentrations and gene expression were associated with AD. We found that higher serum concentrations of BAs are associated with lower brain amyloid deposition, slower WML accumulation, and slower brain atrophy in males. Opposite effects were observed in females. Modulation of BA levels alters risk of incident VaD in males. Altered brain BA signaling at the metabolite and gene expression levels occurs in AD. Dysregulation of peripheral cholesterol catabolism and BA synthesis may impact dementia pathogenesis through signaling pathways in the brain.


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