PUBLICATION

Altered Behavioral Performance and Live Imaging of Circuit-Specific Neural Deficiencies in a Zebrafish Model for Psychomotor Retardation

Authors

Zada, D., Tovin, A., Lerer-Goldshtein, T., Vatine, G.D., Appelbaum, L.

ID

ZDB-PUB-140926-1

Date

2014

Source

PLoS Genetics 10: e1004615 (Journal)

Registered Authors

Appelbaum, Lior, Tovin, Adi, Vatine, Gad, Zada, David

Keywords

Embryos, Larvae, Zebrafish, Axons, Motor neurons, Gene expression, Biological locomotion, Sleep

MeSH Terms

Gene Order
Monocarboxylic Acid Transporters/genetics
Thyroid Hormone Receptors alpha/genetics
Neurogranin/genetics
Zebrafish
X-Linked Intellectual Disability/diagnosis*
X-Linked Intellectual Disability/drug therapy
X-Linked Intellectual Disability/etiology*
Gene Expression Regulation/drug effects
Disease Models, Animal
Neurons/metabolism
Thyroid Gland
Animals
Pseudopodia/genetics
Pseudopodia/metabolism
Myelin Sheath/metabolism
Kruppel-Like Transcription Factors/genetics
Mutation
Thyroid Hormones/pharmacology
Motor Activity/genetics
Zinc Fingers
Animals, Genetically Modified
Gene Knockout Techniques
Hypothalamo-Hypophyseal System
Muscular Atrophy/diagnosis*
Muscular Atrophy/drug therapy
Muscular Atrophy/etiology*
Gene Targeting
Photoperiod
Muscle Hypotonia/diagnosis*
Muscle Hypotonia/drug therapy
Muscle Hypotonia/etiology*
Phenotype

(all 33)

PubMed

25255244 Full text @ PLoS Genet.

Abstract

The mechanisms and treatment of psychomotor retardation, which includes motor and cognitive impairment, are indefinite. The Allan-Herndon-Dudley syndrome (AHDS) is an X-linked psychomotor retardation characterized by delayed development, severe intellectual disability, muscle hypotonia, and spastic paraplegia, in combination with disturbed thyroid hormone (TH) parameters. AHDS has been associated with mutations in the monocarboxylate transporter 8 (mct8/slc16a2) gene, which is a TH transporter. In order to determine the pathophysiological mechanisms of AHDS, MCT8 knockout mice were intensively studied. Although these mice faithfully replicated the abnormal serum TH levels, they failed to exhibit the neurological and behavioral symptoms of AHDS patients. Here, we generated an mct8 mutant (mct8-/-) zebrafish using zinc-finger nuclease (ZFN)-mediated targeted gene editing system. The elimination of MCT8 decreased the expression levels of TH receptors; however, it did not affect the expression of other TH-related genes. Similar to human patients, mct8-/- larvae exhibited neurological and behavioral deficiencies. High-throughput behavioral assays demonstrated that mct8-/- larvae exhibited reduced locomotor activity, altered response to external light and dark transitions and an increase in sleep time. These deficiencies in behavioral performance were associated with altered expression of myelin-related genes and neuron-specific deficiencies in circuit formation. Time-lapse imaging of single-axon arbors and synapses in live mct8-/- larvae revealed a reduction in filopodia dynamics and axon branching in sensory neurons and decreased synaptic density in motor neurons. These phenotypes enable assessment of the therapeutic potential of three TH analogs that can enter the cells in the absence of MCT8. The TH analogs restored the myelin and axon outgrowth deficiencies in mct8-/- larvae. These findings suggest a mechanism by which MCT8 regulates neural circuit assembly, ultimately mediating sensory and motor control of behavioral performance. We also propose that the administration of TH analogs early during embryo development can specifically reduce neurological damage in AHDS patients.

Genes / Markers

Figures

Show all Figures

Expression

Gene	Fish	Conditions	Stage	Anatomy	Assay	Figure
EGFP	biu2Tg	standard conditions	Long-pec	motor neuron	IFL	Fig. 6
EGFP	biu3Tg; biu5Tg	standard conditions	Day 6	motor neuron synapse	ISH	Fig. 6
EGFP	biu3Tg; biu5Tg	standard conditions	Prim-15	motor neuron	ISH	Fig. 6
EGFP	biu3Tg; biu5Tg	standard conditions	Prim-15	spinal cord	ISH	Fig. 6
EGFP	slc16a2^biu4/biu4; biu3Tg; biu5Tg	standard conditions	Day 6	motor neuron synapse	ISH	Fig. 6
klf9	WT	standard conditions	Day 6	forebrain	ISH	Fig. 2
klf9	WT	standard conditions	Day 6	hindbrain	ISH	Fig. 2
klf9	WT	standard conditions	Day 6	midbrain	ISH	Fig. 2
mbpa	WT	standard conditions	Protruding-mouth	anterior lateral line	ISH	Fig. 3
mbpa	WT	standard conditions	Protruding-mouth	posterior lateral line	ISH	Fig. 3

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Phenotype

Fish	Conditions	Stage	Phenotype	Figure
slc16a2^biu4/biu4	standard conditions	Long-pec	Rohon-Beard neuron collateral sprouting decreased process quality, abnormal	Fig. 7
slc16a2^biu4/biu4	standard conditions	Long-pec	Rohon-Beard neuron collateral sprouting decreased process quality, abnormal	Fig. 8
slc16a2^biu4/biu4	standard conditions	Long-pec	Rohon-Beard neuron has fewer parts of type Rohon-Beard neuron dendritic filopodium, abnormal	Fig. 8
slc16a2^biu4/biu4	standard conditions	Long-pec	Rohon-Beard neuron neuron projection decreased branchiness, abnormal	Fig. 7
slc16a2^biu4/biu4	standard conditions	Long-pec	Rohon-Beard neuron neuron projection malformed, abnormal	Fig. 7
slc16a2^biu4/biu4	standard conditions	Protruding-mouth	myelination process quality, abnormal	Fig. 3
slc16a2^biu4/biu4	standard conditions	Day 6	locomotion involved in locomotory behavior process quality, abnormal	Fig. 4
slc16a2^biu4/biu4	standard conditions	Day 6	locomotion process quality, abnormal	Fig. 4
slc16a2^biu4/biu4	standard conditions	Day 6	sleep process quality, abnormal	Fig. 5
slc16a2^biu4/biu4; biu3Tg; biu5Tg	standard conditions	Day 6	motor neuron neuron projection has fewer parts of type motor neuron synapse, abnormal	Fig. 6

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
biu2Tg	Tg(slc16a2:EGFP)	Transgenic Insertion
biu3Tg	Tg(slc16a2:GAL4-VP16)	Transgenic Insertion
biu4		Small Deletion	slc16a2
biu5Tg	Tg(UAS:sypb-EGFP)	Transgenic Insertion
mde4Tg	Tg2(elavl3:GAL4-VP16)	Transgenic Insertion
mde6Tg	Tg(UAS-E1B:mYFP,mitoCFP)	Transgenic Insertion

1 - 6 of 6

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Human Disease / Model

Human Disease	Fish	Conditions	Evidence
Allan-Herndon-Dudley syndrome	slc16a2^biu4/biu4	standard conditions	TAS

Sequence Targeting Reagents

Fish

Fish
biu2Tg
biu3Tg
biu3Tg; biu5Tg
biu5Tg
mde4Tg
mde4Tg; mde6Tg
mde6Tg
slc16a2^biu4/biu4
slc16a2^biu4/biu4; biu3Tg; biu5Tg
slc16a2^biu4/biu4; mde4Tg; mde6Tg

Antibodies

Orthology

Engineered Foreign Genes

Marker	Marker Type	Name
EGFP	EFG	EGFP
GAL4	EFG	GAL4
mitoCFP	EFG	mitoCFP
mYFP	EFG	mYFP
YFP	EFG	YFP

Mapping

Zada et al., 2014 ZDB-PUB-140926-1 PMID:25255244

Altered Behavioral Performance and Live Imaging of Circuit-Specific Neural Deficiencies in a Zebrafish Model for Psychomotor Retardation

Zada et al., 2014

ZDB-PUB-140926-1
PMID:25255244