PUBLICATION

Rapamycin relieves the cataract caused by ablation of Gja8b through stimulating autophagy in zebrafish

Authors

Ping, X., Liang, J., Shi, K., Bao, J., Wu, J., Yu, X., Tang, X., Zou, J., Shentu, X.

ID

ZDB-PUB-210123-4

Date

2021

Source

Autophagy 17(11): 3323-3337 (Journal)

Registered Authors

Zou, Jian

Keywords

3-MA, GJA8, Gja8b, autophagy, cataract, lens, organelle degradation, rapamycin

MeSH Terms

Lens, Crystalline/abnormalities
Lens, Crystalline/growth & development
Lens, Crystalline/physiology
Animals
Zebrafish Proteins/antagonists & inhibitors*
Zebrafish Proteins/genetics*
Zebrafish Proteins/physiology
Cataract/genetics*
Cataract/pathology
Cataract/physiopathology
Sirolimus/pharmacology*
Adenine/analogs & derivatives
Adenine/pharmacology
Mutation
Autophagy/drug effects*
Autophagy/genetics*
Autophagy/physiology
Animals, Genetically Modified
Zebrafish/genetics*
Zebrafish/physiology*
Connexins/antagonists & inhibitors*
Connexins/genetics*
Connexins/physiology

(all 23)

PubMed

33472493 Full text @ Autophagy

Abstract

Macroautophagy/autophagy is known to be important for intracellular quality control in the lens. GJA8 is a major gap junction protein in vertebrate lenses. Mutations in GJA8 cause cataracts in humans. The well-known cataractogenesis mechanism is that mutated GJA8 leads to abnormal assembly of gap junctions, resulting in defects in intercellular communication among lens cells. In this study, we observed that ablation of Gja8b (a homolog of mammalian GJA8) in zebrafish led to severe defects in organelle degradation, an important cause of cataractogenesis in developing lens. The role of autophagy in organelle degradation in lens remains disputable. Intriguingly, we also observed that ablation of Gja8b induced deficient autophagy in the lens. More importantly, in vivo treatment of zebrafish with rapamycin, an autophagy activator that inhibits MAPK/JNK and MTORC1 signaling, stimulated autophagy in the lens and relieved the defects in organelle degradation, resulting in the mitigation of cataracts in gja8b mutant zebrafish. Conversely, inhibition of autophagy by treatment with the chemical reagent 3-MA blocked these recovery effects, suggesting the important roles of autophagy in organelle degradation in the lens in gja8b mutant zebrafish. Further studies in HLE cells revealed that GJA8 interacted with ATG proteins. Overexpression of GJA8 stimulated autophagy in HLE cells. These data suggest an unrecognized cataractogenesis mechanism caused by ablation of Gja8b and a potential treatment for cataracts by stimulating autophagy in the lens. Abbreviations: 3-MA: 3-methyladenine; ATG: autophagy related; AV: autophagic vacuoles; Dpf: days post fertilization; GJA1: gap junction protein alpha 1; GJA3: gap junction protein alpha 3; GJA8: gap junction protein alpha 8; Hpf: hours post fertilization; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PtdIns3K: class III phosphatidylinositol 3-kinase; WT: wild type.

Genes / Markers

Figures

Show all Figures

Expression

Phenotype

Fish	Conditions	Stage	Phenotype	Figure
AB	chemical treatment by environment: 3-methyladenine	Protruding-mouth	lens central region has extra parts of type lens fiber cell cytoskeleton, abnormal	Fig. 8
AB	chemical treatment by environment: 3-methyladenine	Protruding-mouth	lens central region has extra parts of type lens fiber cell endoplasmic reticulum, abnormal	Fig. 8
AB	chemical treatment by environment: 3-methyladenine	Protruding-mouth	lens central region has extra parts of type lens fiber cell nucleus, abnormal	Fig. 8
AB	chemical treatment by environment: 3-methyladenine	Protruding-mouth	lens development in camera-type eye decreased process quality, abnormal	Fig. 8
AB	chemical treatment by environment: 3-methyladenine	Protruding-mouth	lens fiber cell endoplasmic reticulum disassembly decreased process quality, abnormal	Fig. 8
gja8b^{zko933a/zko933a}	control	Protruding-mouth	lens ab1-mip labeling increased amount, abnormal	Fig. 7
gja8b^{zko933a/zko933a}	control	Protruding-mouth	lens Ab14-hspa5 labeling increased amount, abnormal	Fig. 7
gja8b^{zko933a/zko933a}	control	Protruding-mouth	lens central region has extra parts of type lens fiber cell cytoskeleton, abnormal	Fig. 7
gja8b^{zko933a/zko933a}	control	Protruding-mouth	lens central region has extra parts of type lens fiber cell endoplasmic reticulum, abnormal	Fig. 7
gja8b^{zko933a/zko933a}	control	Protruding-mouth	lens central region has extra parts of type lens fiber cell nucleus, abnormal	Fig. 7

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Mutations / Transgenics

Allele	Construct	Type	Affected Genomic Region
zko933a		Insertion	gja8b

Human Disease / Model

Human Disease	Fish	Conditions	Evidence
cataract			TAS

Sequence Targeting Reagents

Target	Reagent	Reagent Type
gja8b	CRISPR1-gja8b	CRISPR

Fish

Fish
AB
gja8b^{zko933a/zko933a}

Antibodies

Name	Type	Antigen Genes	Isotypes	Host Organism
Ab1-mip	polyclonal			Rabbit
Ab1-prkcz	polyclonal	prkci prkcz	IgG	Rabbit
Ab1-tjp1	monoclonal	tjp1a tjp1b	IgG1	Mouse
Ab4-map1lc3b	polyclonal			Rabbit
Ab14-hspa5	monoclonal		IgG2a	Mouse
zl-1	monoclonal		IgG1	Mouse

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Orthology

Engineered Foreign Genes

Mapping

Ping et al., 2021 ZDB-PUB-210123-4 PMID:33472493

Rapamycin relieves the cataract caused by ablation of Gja8b through stimulating autophagy in zebrafish

Ping et al., 2021

ZDB-PUB-210123-4
PMID:33472493