Loss of CREST leads to neuroinflammatory responses and ALS-like motor defects in mice

Cheng Cheng,Shifang Shan,Anirvan Ghosh,Aaron Gitler,Zilong Qiu,Kan Yang,Xinwei Wu,Yuefang Zhang

doi:10.1186/s40035-019-0152-1

Abstract

BackgroundAmyotrophic lateral sclerosis (ALS) is a late onset neurodegenerative disease with fast progression. ALS has heavy genetic components in which a series of genetic mutations have been identified. In 2013, Mutations of the CREST gene (also known as SS18L1), which functions as a calcium-regulated transcriptional activator, were found in sporadic ALS patients. However, the pathogenic causality and mechanisms of ALS-associated mutations of CREST remain to be determined.MethodsIn this study, we constructed CREST knockout and Q394X knock-in mice with CRISPR/Cas9 system. Using biochemical and imaging tools, we illustrated core pathological phenotypes in CREST mutant mice and claimed the possible pathogenic mechanisms. Furthermore, we also observed locomotion defects in CREST mutant mice with behavioural tests.ResultsWe demonstrate that ALS-related CREST-Q388X mutation exhibits loss-of-function effects. Importantly, the microglial activation was prevalent in CREST haploinsufficiency mice and Q394X mice mimicking the human CREST Q388X mutation. Furthermore, we showed that both CREST haploinsufficiency and Q394X mice displayed deficits in motor coordination. Finally, we identified the critical role of CREST-BRG1 complex in repressing the expression of immune-related cytokines including Ccl2 and Cxcl10 in neurons, via histone deacetylation, providing the molecular mechanisms underlying inflammatory responses within mice lack of CREST.ConclusionOur findings indicate that elevated inflammatory responses in a subset of ALS may be caused by neuron-derived factors, suggesting potential therapeutic methods through inflammation pathways.

Highlights

Amyotrophic lateral sclerosis (ALS) is a late onset neurodegenerative disease with fast progression
There was no statistical difference between basal levels of Calcium-responsive transactivator (CREST) WT and Q388X mutant protein, we surprisingly found that the protein level of Q388X mutant was significantly reduced compared to WT if protein synthesis was blocked by cycloheximide (CHX) treatment, suggesting that protein stability of CREST-Q388X mutant is much lower compared to WT in cultured neurons in vitro (Fig. 1a and b)
We found that protein level of CREST declined about 20% in brain and spinal cord of Q394X mice compared to WT mice, indicating that Q394X mutation leads to instability of endogenous CREST protein in vivo (Fig. 1f and g)

Summary

Introduction

Amyotrophic lateral sclerosis (ALS) is a late onset neurodegenerative disease with fast progression. ALS has heavy genetic components in which a series of genetic mutations have been identified. The pathogenic causality and mechanisms of ALS-associated mutations of CREST remain to be determined. Amyotrophic lateral sclerosis (ALS) is one of the most severe neurodegenerative diseases characterized by the fast progressive degeneration of motor neurons in the central nervous system (CNS). ALS has heavy genetic components in which a series of genetic mutations have been. Several de novo and inherited mutations in CREST have been recently reported in ALS patients via NGS-based whole-exome sequencing or target gene sequencing approaches [8,9,10], suggesting that CREST may be a potential ALS-causing gene. We focus on one de novo missense mutation, CREST-Q388X, which leads to a truncation that lacks nine amino acids in the C-terminus [8]

Methods

Results

Discussion

Conclusion