C-Ret-mediated hearing loss in mice with Hirschsprung disease.
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ABSTRACT:
SUBMITTER: Ohgami N
PROVIDER: S-EPMC2919946 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The c-RET proto-oncogene encodes a receptor-tyrosine kinase. Loss-of-function mutations of RET have been shown to be associated with Hirschsprung disease and Down's syndrome (HSCR-DS) in humans. DS is known to involve cerebellar hypoplasia, which is characterized by reduced cerebellar size. Despite the fact that c-Ret has been shown to be associated with HSCR-DS in humans and to be expressed in Purkinje cells (PCs) in experimental animals, there is limited information about the role of activity of c-Ret/c-RET kinase in cerebellar hypoplasia. We found that a loss-of-function mutation of c-Ret Y1062 in PCs causes cerebellar hypoplasia in c-Ret mutant mice. Wild-type mice had increased phosphorylation of c-Ret in PCs during postnatal development, while c-Ret mutant mice had postnatal hypoplasia of the cerebellum with immature neurite outgrowth in PCs and granule cells (GCs). c-Ret mutant mice also showed decreased numbers of glial fibers and mitogenic sonic hedgehog (Shh)-positive vesicles in the external germinal layer of PCs. c-Ret-mediated cerebellar hypoplasia was rescued by subcutaneous injection of a smoothened agonist (SAG) as well as by reduced expression of Patched1, a negative regulator for Shh. Our results suggest that the loss-of-function mutation of c-Ret Y1062 results in the development of cerebellar hypoplasia via impairment of the Shh-mediated development of GCs and glial fibers in mice with HSCR-DS.
| S-EPMC7950328 | biostudies-literature
Project description:Patients with sporadic Hirschsprung disease (HSCR) show increased allele sharing at markers in the 5' region of the RET locus, indicating the presence of a common ancestral RET mutation. In a previous study, we found a haplotype of six SNPs that was transmitted to 55.6% of our patients, whereas it was present in only 16.2% of the controls we used. Among the patients with that haplotype, 90.8% had it on both chromosomes, which led to a much higher risk of developing HSCR than when the haplotype occurred heterozygously. To more precisely define the HSCR-associated region and to identify candidate disease-associated variant(s), we sequenced the shared common haplotype region from 10 kb upstream of the RET gene through intron 1 and exon 2 (in total, 33 kb) in a patient homozygous for the common risk haplotype and in a control individual homozygous for the most common nonrisk haplotype. A comparison of these sequences revealed 86 sequence differences. Of these 86 variations, 8 proved to be in regions highly conserved among different vertebrates and within putative transcription factor binding sites. We therefore considered these as candidate disease-associated variants. Subsequent genotyping of these eight variants revealed a strong disease association for six of the eight markers. These six markers also showed the largest distortions in allele transmission. Interspecies comparison showed that only one of the six variations was located in a region also conserved in a nonmammalian species, making it the most likely candidate HSCR-associated variant.
| S-EPMC1199373 | biostudies-literature
Project description:PurposeWe aimed to determine the frequency of RET mosaicism in Hirschsprung disease (HSCR), test whether it has been underestimated, and to assess its contribution to HSCR risk.MethodsTargeted exome sequencing (n = 83) and RET single-gene screening (n = 69) were performed. Amplicon-based deep sequencing was applied on multiple tissue samples. TA cloning and sequencing were conducted for validation.ResultsWe identified eight de novo mutations in 152 patients (5.2%), of which six were pathogenic mosaic mutations. Two of these patients were somatic mosaics, with mutations detected in blood, colon, and saliva (mutant allele frequency: 35-44%). In addition, germ-line mosaicism was identified in four clinically unaffected subjects, each with an affected child, in multiple tissues (mutant allele frequency: 1-28%).ConclusionSomatic mutations of the RET gene are underrecognized in HSCR. Molecular investigation of the parents of patients with seemingly sporadic mutations is essential to determine recurrence risk in these families.
| S-EPMC7814876 | biostudies-literature
Project description:Appropriately balanced RET signaling is of crucial importance during embryonic neural crest cell migration, proliferation and differentiation. RET deficiency, for example, leads to intestinal aganglionosis (Hirschsprung disease), whereas overactive RET can lead to multiple endocrine neoplasia (MEN) syndromes. Some RET mutations are associated with both intestinal aganglionosis and MEN-associated tumors. This seemingly paradoxical occurrence has led to speculation of a 'Janus mutation' in RET that causes overactivation or impairment of RET activity depending on the cellular context. Using an intestinal catenary culture system to test the effects of GDNF-mediated RET activation, we demonstrate the concurrent development of distal colonic aganglionosis and intestinal ganglioneuromas. Interestingly, the tumors induced by GDNF stimulation contain enteric neuronal progenitors capable of reconstituting an enteric nervous system when transplanted into a normal developmental environment. These results suggest that a Janus mutation may not be required to explain co-existing Hirschsprung disease and MEN-associated tumors, but rather that RET overstimulation alone is enough to cause both phenotypes. The results also suggest that reprogramming tumor cells toward non-pathological fates may represent a possible therapeutic avenue for MEN-associated neoplasms.
| S-EPMC7657479 | biostudies-literature
Project description:BackgroundHSCR is a complex genetic disorder characterized by the absence of ganglion cells in the intestine, leading to a functional obstruction. It is due to a disruption of complex signaling pathways within the gene regulatory network (GRN) during the development of the enteric nervous system (ENS), including SRY-Box Transcription Factor 10 (SOX10) and REarranged during Transfection (RET). This study evaluated the expressions of SOX10 and RET in HSCR patients in Indonesia.MethodsTotal RNA of 19 HSCR ganglionic and aganglionic colons and 16 control colons were analyzed using quantitative real-time polymerase chain reaction for SOX10 and RET with GAPDH as the reference gene. Livak's method (2-ΔΔCT) was used to determine the expression levels of SOX10 and RET.ResultsMost patients were males (68.4%), in the short aganglionosis segment (78.9%), and had undergone transanal endorectal pull-through (36.6%). There were significant upregulated SOX10 expressions in both ganglionic (2.84-fold) and aganglionic (3.72-fold) colon of HSCR patients compared to controls' colon (ΔCT 5.21 ± 2.04 vs. 6.71 ± 1.90; p = 0.032; and ΔCT 4.82 ± 1.59 vs. 6.71 ± 1.90; p = 0.003; respectively). Interestingly, the RET expressions were significantly downregulated in both ganglionic (11.71-fold) and aganglionic (29.96-fold) colon of HSCR patients compared to controls' colon (ΔCT 12.54 ± 2.21 vs. 8.99 ± 3.13; p = 0.0004; and ΔCT 13.90 ± 2.64 vs. 8.99 ± 3.13; p = 0.0001; respectively).ConclusionsOur study shows aberrant SOX10 and RET expressions in HSCR patients, implying the critical role of SOX10 and RET in the pathogenesis of HSCR, particularly in the Indonesian population. Our study further confirms the involvement of SOX10-RET within the GNR during the ENS development.
| S-EPMC10943800 | biostudies-literature
Project description:Background RET and Semaphorin 3 (SEMA3) common variants have been associated with Hirschsprung disease (HSCR), but their genetic interactions for development of HSCR is not established yet. To determine the joint effects of RET gene, rs2435357, and SEMA3 gene with three markers; rs1583147, rs12707682, and rs11766001 polymorphisms in Indonesian HSCR patients. Methods Sixty HSCR patients and 115 non-HSCR controls were included in this study. Four genetic markers of the RET and SEMA3 were examined in 175 DNAs using TaqMan Genotyping assay. Case-control analysis and transmission disequilibrium test (TDT) were used to determine an association between four genetic markers and HSCR. We used a P value of <0.013 for a significant association. Results There was a strong association between RET rs2435357 marker and HSCR either by case-control analysis (OR =4.46, P=2.5×10?8) or TDT (P=4.2×10?6), but not SEMA3 rs1583147 (OR =1.9, P=0.023 and P=0.11, respectively) and rs12707682 (OR =1.5, P=0.06 and P=0.041, respectively). Two locus analyses of variants revealed that RET rs2435357 (TT), in combination with SEMA3 rs1583147 (CT) or rs12707682 (CC), were associated with the augmented disease risks of HSCR (OR =2.88, P=0.016 and OR =19.9, P=0.005, respectively) compared with a single variant of SEMA3 rs1583147 or rs12707682. Moreover, the SEMA3 rs11766001 frequencies in HSCR patients and non-HSCR subjects were 1.7% and 0.8% (P=0.48), respectively. Conclusions The genetic effects of SEMA3 genotypes are epistatic to RET. The rarity of SEMA3 rs11766001 in Indonesia could be explained by the founder effect.
| S-EPMC5641808 | biostudies-literature
Project description:Background Hirschsprung disease (HSCR) is a complex genetic disorder, which characterized by absence of ganglion cells along variable lengths of the intestines in neonates, with the RET was identified as a major locus involved in HSCR. In this study, we investigated the joint effects of common variants within the RET transcriptional enhancer, rs2435357 and rs2506030, for development of HSCR in Indonesia. Methods Sixty HSCR patients and 122 non-HSCR controls was involved in this study. Two genetic markers of the RET were examined using TaqMan assay. We analyzed the case-control association tests between two genetic markers and HSCR using the statistic. A P value <0.025 is considered significant given that two tests (markers) were performed in the analysis. Results There was high correlation between RET rs2435357 marker and HSCR either by case-control analysis (OR =4.46, P=2.5×10?8) or transmission disequilibrium test (TDT, P=4.2×10?6), but not RET rs2506030 (OR =1.68, P=0.042 and P=0.034, respectively). Two locus analyses of variants revealed that RET rs2435357 (TT), in combination with rs2506030 (GG), were associated with the increased disease risks of HSCR (OR =5.42, P=3.9×10?6) compared with a single variant of rs2506030. Conclusions Our study shows that RET rs2435357 variant is a strong genetic risk factors for development of HSCR in Indonesia. In addition, the disease effects of RET rs2506030 genotypes are crucially dependent on the effects of rs2435357 genotypes.
| S-EPMC5641765 | biostudies-literature
Project description:Rare (RVs) and common variants of the RET gene contribute to Hirschsprung disease (HSCR; congenital aganglionosis). While RET common variants are strongly associated with the commonest manifestation of the disease (males; short-segment aganglionosis; sporadic), rare coding sequence (CDS) variants are more frequently found in the lesser common and more severe forms of the disease (females; long/total colonic aganglionosis; familial).Here we present the screening for RVs in the RET CDS and intron/exon boundaries of 601 Chinese HSCR patients, the largest number of patients ever reported. We identified 61 different heterozygous RVs (50 novel) distributed among 100 patients (16.64%). Those include 14 silent, 29 missense, 5 nonsense, 4 frame-shifts, and one in-frame amino-acid deletion in the CDS, two splice-site deletions, 4 nucleotide substitutions and a 22-bp deletion in the intron/exon boundaries and 1 single-nucleotide substitution in the 5' untranslated region. Exonic variants were mainly clustered in RET the extracellular domain. RET RVs were more frequent among patients with the most severe phenotype (24% vs. 15% in short-HSCR). Phasing RVs with the RET HSCR-associated haplotype suggests that RVs do not underlie the undisputable association of RET common variants with HSCR. None of the variants were found in 250 Chinese controls.
| S-EPMC3235168 | biostudies-literature
Project description:Disruptions in gene regulatory networks (GRNs), driven by multiple deleterious variants, potentially underlie complex traits and diseases. Hirschsprung disease (HSCR), a multifactorial disorder of enteric nervous system (ENS) development, is associated with at least 24 genes and seven chromosomal loci, with RET and EDNRB as its major genes. We previously demonstrated that RET transcription in the ENS is controlled by an extensive GRN involving the transcription factors (TFs) RARB, GATA2 and SOX10 and other HSCR genes. We now demonstrate, using human and mouse cellular and animal models, that EDNRB is transcriptionally regulated in the ENS by GATA2, SOX10 and NKX2.5 TFs. Significantly, RET and EDNRB expression is regulated by their shared use of GATA2 and SOX10, and in turn, these TFs are controlled by EDNRB and RET in a dose-dependent manner. This study expands the ENS development GRN to include both RET and EDNRB, uncovers the mechanistic basis for RET-EDNRB epistasis and emphasizes how functionally different genes associated with a complex disorder can be united through a common GRN.
| S-EPMC7275776 | biostudies-literature
Project description:Common variants in RET and NRG1 have been associated with Hirschsprung disease (HSCR), a congenital disorder characterised by incomplete innervation of distal gut, in East Asian (EA) populations. However, the allelic effects so far identified do not fully explain its heritability, suggesting the presence of epistasis, where effect of one genetic variant differs depending on other (modifier) variants. Few instances of epistasis have been documented in complex diseases due to modelling complexity and data challenges. We proposed four epistasis models to comprehensively capture epistasis for HSCR between and within RET and NRG1 loci using whole genome sequencing (WGS) data in EA samples. 65 variants within the Topologically Associating Domain (TAD) of RET demonstrated significant epistasis with the lead enhancer variant (RET+3; rs2435357). These epistatic variants formed two linkage disequilibrium (LD) clusters represented by rs2506026 and rs2506028 that differed in minor allele frequency and the best-supported epistatic model. Intriguingly, rs2506028 is in high LD with one cis-regulatory variant (rs2506030) highlighted previously, suggesting that detected epistasis might be mediated through synergistic effects on transcription regulation of RET. Our findings demonstrated the advantages of WGS data for detecting epistasis, and support the presence of interactive effects of regulatory variants in RET for HSCR.
| S-EPMC9705416 | biostudies-literature