Cereblon Control of Zebrafish Brain Size by Regulation of Neural Stem Cell Proliferation

Abstract

Summary Thalidomide is a teratogen that causes multiple malformations in the developing baby through its interaction with cereblon (CRBN), a substrate receptor subunit of the CRL4 E3 ubiquitin ligase complex. CRBN was originally reported as a gene associated with autosomal recessive non-syndromic mild mental retardation. However, the function of CRBN during brain development remains largely unknown. Here we demonstrate that CRBN promotes brain development by facilitating the proliferation of neural stem cells (NSCs). Knockdown of CRBN in zebrafish embryos impaired brain development and led to small brains, as did treatment with thalidomide. By contrast, overexpression of CRBN resulted in enlarged brains, leading to the expansion of NSC regions and increased cell proliferation in the early brain field and an expanded expression of brain region-specific genes and neural and glial marker genes. These results demonstrate that CRBN functions in the determination of brain size by regulating the proliferation of NSCs during development.

Early preclinical screening using zebrafish (Danio rerio) reveals the safety of the candidate anti-inflammatory therapeutic agent TnP

“…Behavioral studies as locomotor activity have identified strong associations between the functions of zebrafish and human brain regions [ 38 ]. Finally, we confirmed that 0 hpf embryos microinjected with Tn P presented at 28 and 48 hpf a developed brain with forebrain, midbrain, and hindbrain, suggesting that the formation of structures or neurogenesis [ 60 , 61 ] were not affected by Tn P.…”

Waking up quiescent neural stem cells: Molecular mechanisms and implications in neurodevelopmental disorders

“…Analogous to the microcephaly-like brains observed in Drosophila ddb1 mutants, in the mouse developing brain, a CNS-specific depletion of DDB1 leads to decreased NSC proliferation and the formation of smaller brains [153]. In zebrafish, the CRL4 complex with a substrate receptor named cereblon (CRBN) controls NSC proliferation and brain size [154,155]. Zebrafish ddb1or CRBN-depleted embryos develop smaller brains with a reduction of the number of proliferating cells [154,155].…”

“…In zebrafish, the CRL4 complex with a substrate receptor named cereblon (CRBN) controls NSC proliferation and brain size [154,155]. Zebrafish ddb1or CRBN-depleted embryos develop smaller brains with a reduction of the number of proliferating cells [154,155]. Variants of human Cul4B are associated with neurodevelopmental disorders, including X-linked ID, mental retardation, and cortical malformations [156][157][158][159].…”

Experimental Models to Study Autism Spectrum Disorders: hiPSCs, Rodents and Zebrafish

“…Regarding morphological characterization, the parameters to be analyzed may include a series of general observations such as body, heart, head, eyes otolith or jaw malformations, yolk deformation or edema and tail bending. Secondly, in order to determine if there exists a delay or abnormality in development some measures might be taken, such as body length, head, eye and yolk sac area or otolith–eye and jaw–eye distance, as well as the different brain regions thickness, area and weight [ 246 , 267 , 268 ]. This characterization is image-based and might be performed manually, or with available commercial image software.…”

“…With regard to gene expression patterns, many of the genes mentioned in transgenic lines in Table 8 can serve as markers in qPCR assays, which offer information about how much the gene is expressed, or in in situ hybridization (ISH) assays with RNA probes, which allow localizing where the gene is being expressed in a precise time point. Other markers to perform ISH or qPCR with, that may be useful in neurodevelopment research are sox2 (neural stem cells self-renewal and pluripotency cells), vglut2.2 (glutamatergic marker), th1 (dopaminergic marker), neurog1 (neuronal determination marker), c-fos (neuronal activator marker), crh (paraventricular nucleus neurons), c-myc (tectal proliferation zone and retina), emx1 (telencephalon) or otx2a and pax2a (diencephalon and midbrain–hindbrain boundary) [ 267 , 269 , 270 ]. In addition, immunofluorescence leads the researchers to know where the protein is acting, and if there are differences in the amount of protein among individuals, although these assays are relatively limited in zebrafish due to the absence of several specific antibodies.…”