PUBLICATION
Involvement of Cxcl12a/Cxcr4b Chemokine System in Mediating the Stimulatory Effect of Embryonic Ethanol Exposure on Neuronal Density in Zebrafish Hypothalamus
- Authors
- Collier, A.D., Khalizova, N., Chang, G.Q., Min, S., Campbell, S., Gulati, G., Leibowitz, S.F.
- ID
- ZDB-PUB-201020-50
- Date
- 2020
- Source
- Alcoholism, clinical and experimental research 44(12): 2519-2535 (Journal)
- Registered Authors
- Keywords
- Cxcl12a/Cxcr4b, Zebrafish, chemokine, ethanol, hypothalamus
- MeSH Terms
-
- Animals
- Benzylamines/pharmacology
- Cell Count
- Chemokine CXCL12/metabolism*
- Cyclams/pharmacology
- Embryo, Nonmammalian/drug effects
- Ethanol/pharmacology*
- Hypothalamus/cytology
- Hypothalamus/drug effects*
- Hypothalamus/embryology
- Neurogenesis/drug effects
- Neurons/drug effects*
- Receptors, CXCR4/metabolism*
- Zebrafish/embryology
- Zebrafish Proteins/metabolism*
- PubMed
- 33067812 Full text @ Alcoholism Clin. Exp. Res.
Citation
Collier, A.D., Khalizova, N., Chang, G.Q., Min, S., Campbell, S., Gulati, G., Leibowitz, S.F. (2020) Involvement of Cxcl12a/Cxcr4b Chemokine System in Mediating the Stimulatory Effect of Embryonic Ethanol Exposure on Neuronal Density in Zebrafish Hypothalamus. Alcoholism, clinical and experimental research. 44(12):2519-2535.
Abstract
Background Embryonic exposure to ethanol (EtOH) produces marked disturbances in neuronal development and alcohol-related behaviors, with low-moderate EtOH doses stimulating neurogenesis without producing apoptosis and high doses having major cytotoxic effects while causing gross morphological abnormalities. With the pro-inflammatory chemokine system, Cxcl12 and its main receptor Cxcr4, known to promote processes of neurogenesis, we examined here this neuroimmune system in the embryonic hypothalamus to test directly if it mediates the stimulatory effects low-moderate EtOH doses have on neuronal development.
Methods We used the zebrafish (Danio rerio) model, which develops externally and allows one to investigate the developing brain in vivo with precise control of dose and timing of EtOH delivery in the absence of maternal influence. Zebrafish were exposed to low-moderate EtOH doses (0.1, 0.25, 0.5% v/v), specifically during a period of peak hypothalamic development from 22-24 hours post fertilization, and in some tests were pre-treated from 2-22 hpf with the Cxcr4 receptor antagonist, AMD3100. Measurements in the hypothalamus at 26 hpf were taken of cxcl12a and cxcr4b transcription, signaling, and neuronal density using qRT-PCR, RNAscope, and live-imaging of transgenic zebrafish.
Results Embryonic EtOH exposure, particularly at the 0.5% dose, significantly increased levels of cxcl12a and cxcr4b mRNA in whole-embryos, number of cxcl12a and cxcr4b transcripts in developing hypothalamus, and internalization of Cxcr4b receptors in hypothalamic cells. Embryonic EtOH also stimulated an increase in the number of hypothalamic neurons and coexpression of cxcl12a and cxcr4b transcripts within these neurons. Each of these stimulatory effects of EtOH in the embryo were blocked by pretreatment with Cxcr4 antagonist AMD3100.
Conclusions These results provide clear evidence that EtOH's stimulatory effects at low-moderate doses on the number of hypothalamic neurons early in development are mediated, in part, by increased transcription and intracellular activation of this chemokine system, likely due to autocrine signaling of Cxcl12a at its Cxcr4b receptor within the neurons.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping