The Expression of Shh, Ptch1, and Gli1 in the Developing Caudal Spinal Cord of Fetal Rats With Anorectal Malformations

Transcriptome analysis reveals the spinal expression profiles of non-coding RNAs involved in anorectal malformations in rat fetuses

BACKGROUND

Despite improvements in anorectal malformation (ARM) therapy, patients might still experience post-operative problems such as fecal incontinence, constipation, and soiling. In particular, the dysplasia of the lumbosacral spinal cord in ARM patients is a major disorder that affects fecal function post-operation. However, the pathological mechanisms involved are still unclear.

METHODS

The non-coding RNAs (ncRNAs) in the lumbosacral spinal cord of fetal rats with ethylenethiourea-induced ARM were identified using RNA sequencing (RNA-seq) and examined to determine their potential function. The lumbosacral spinal cord was isolated on embryonic day 17 for subsequent RNA extraction and RNA-seq. The transcriptome data was analyzed using bioinformatics analysis, followed by validation using quantitative reverse transcription PCR.

RESULTS

Compared to the control group, 26 differentially expressed microRNAs (DEMs; 22 upregulated, 4 downregulated) and 112 differentially expressed long non-coding RNAs (63 upregulated, 49 downregulated) were identified in the ARM group. Several DEMs related to development, namely miR-200a-3p, miR-200b-3p, miR-200c-3p, miR-200a-5p, and miR-429, were selected for further analysis. Notably, compared to the control, the relative expression of miR-200 family members was highly upregulated in ARM fetal rats. Furthermore, GO and KEGG enrichment and miRNA-transcription factor-lncRNA/mRNA network analysis was explored to show molecular mechanism underlying DEMs.

CONCLUSIONS

Our findings suggest the involvement of ncRNAs, especially the miR-200 family members, in the pathogenesis of lumbosacral spinal cord dysplasia in ARM fetal rats.

Global Development of Research on Anorectal Malformations over the Last Five Decades: A Bibliometric Analysis

Purpose: Anorectal malformations (ARM) are one of the most challenging congenital malformations in pediatric surgery. We aimed to assess the research activity on ARM over the last five decades. Methods: Data on original research publications were retrieved from the Web of Science Core Collection (1970–2020), and analyzed for countries, authors, scientific journals, and top-ten papers. Scientific quantity was assessed by the number of publications. Research quality was estimated from the number of citations, average citation rate per item (ACI), and h-index. Results: A total number of 1595 articles with 19,419 citations (ACI = 12.2; h-index = 54) were identified. The annual number of publications and citations significantly increased over time (p < 0.0001). The USA (n = 386; 24.2%), Japan (n = 153; 9.6%), and China (n = 137; 8.6%) were the most productive countries; and the USA (n = 7850; ACI = 20.3; h-index = 44), Japan (n = 1937; ACI = 12.6; h-index = 21), and the Netherlands (n = 1318; ACI = 17.3; h-index = 22) were the top cited countries. Articles were preferentially published in JPS (n = 391; 24.5%), PSI (n = 181; 11.3%), and EJPS (n = 56; 3.5%). Top-ten cited papers focused on classification (n = 1), surgical technique (n = 3), associated syndromes (n = 2), postoperative outcome (n = 3), and basic research (n = 1). Conclusion: This bibliometric study provides valuable insights into the global development of ARM research, and shows that clinical studies and international collaborations dominate in this field.

Bioinformatics analysis of candidate genes involved in ethanol-induced microtia pathogenesis based on a human genome database: GeneCards

OBJECTIVE

Ethanol used by women during pregnancy increases the risk for microtia in the foetus. Traditionally, laboratory experiments and Mouse Genome Informatics (MGI) have been used to explore microtia pathogenesis. The aim of this study was to screen and verify hub genes involved in ethanol-induced microtia and to explore the potential molecular mechanisms.

METHODS

Overlapping genes related to ethanol and microtia were acquired from the GeneCards database and filtered by confidence score. These genes were further analysed via bioinformatics. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results were visualized with the clusterProfiler R package. A protein-protein interaction (PPI) network was constructed based on data from the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database.

RESULTS

Overall, 41 genes related to both ethanol and microtia were identified. The genes most relevant to ethanol-induced microtia pathogenesis included FGFR-2, FGFR-3, FGF-8, TP53, IGF1, SHH, CTNNB1, and PAX6, among others. Most genes were strongly enriched for tissue and organ development in GO analysis. Additionally, many genes were enriched in the Ras, FoxO, MAPK, and PI3K-Akt signalling pathways in KEGG analysis.

CONCLUSIONS

Bioinformatics analysis was conducted on genes currently known to be related to ethanol-induced microtia pathogenesis. We propose that mechanisms involving FGF-family genes, TP53, IGF1 and SHH contribute significantly to ethanol-induced microtia and the accompanying malformation of other structures.

Spatiotemporal expression of neurogenic locus notch homolog protein 1 in developing caudal spinal cord of fetuses with anorectal malformations from ETU-fed rats

Complications, such as fecal soiling, incontinence, and constipation, are major health issues for patients with anorectal malformations (ARMs) after surgery. Dysplasia of the caudal spinal cord is an increasingly pivotal area in the field of postoperative complications for patients with ARMs. However, the existing research has not fully defined the mechanism underlying ARMs development. The neurogenic locus notch homolog (Notch) signaling pathway comprises several highly conserved proteins that are involved in spinal cord developmental processes. In the present study, the emerging role of Notch1 in fetal lumbosacral spinal cords was investigated in a rat model of ARMs using ethylene thiourea. Immunohistochemical staining, western blot and quantitative reverse transcription real-time polymerase chain reaction were utilized to analyze spatiotemporal expression of Notch1 on embryonic days (E) 16, E17, E19, and E21. The expression levels of the neuronal marker neurofilament and recombination signal-binding protein-J protein were evaluated for temporal correlations to Notch1 expression. The results implied that Notch1 expression was reduced in lumbosacral spinal cord neurons of ARMs embryos compared to control embryos. These results showed that, in ARMs embryos decreased Notch1 expression is related to the dysplasia of the caudal spinal cord during embryogenesis, indicating that Notch signaling may participate pathogenic embryonic lumbosacral spinal development and may be associated with postoperative complications of ARMs.

Sonic Hedgehog-Gli1 Signaling and Cellular Retinoic Acid Binding Protein 1 Gene Regulation in Motor Neuron Differentiation and Diseases

Cellular retinoic acid-binding protein 1 (CRABP1) is highly expressed in motor neurons. Degenerated motor neuron-like MN1 cells are engineered by introducing SOD^G93A or AR-65Q to model degenerated amyotrophic lateral sclerosis (ALS) or spinal bulbar muscular atrophy neurons. Retinoic acid (RA)/sonic hedgehog (Shh)-induced embryonic stem cells differentiation into motor neurons are employed to study up-regulation of Crabp1 by Shh. In SOD^G93A or AR-65Q MN1 neurons, CRABP1 level is reduced, revealing a correlation of motor neuron degeneration with Crabp1 down-regulation. Up-regulation of Crabp1 by Shh is mediated by glioma-associated oncogene homolog 1 (Gli1) that binds the Gli target sequence in Crabp1′s neuron-specific regulatory region upstream of minimal promoter. Gli1 binding triggers chromatin juxtaposition with minimal promoter, activating transcription. Motor neuron differentiation and Crabp1 up-regulation are both inhibited by blunting Shh with Gli inhibitor GANT61. Expression data mining of ALS and spinal muscular atrophy (SMA) motor neurons shows reduced CRABP1, coincided with reduction in Shh-Gli1 signaling components. This study reports motor neuron degeneration correlated with down-regulation in Crabp1 and Shh-Gli signaling. Shh-Gli up-regulation of Crabp1 involves specific chromatin remodeling. The physiological and pathological implication of this regulatory pathway in motor neuron degeneration is supported by gene expression data of ALS and SMA patients.

BMP7 is Downregulated in Lumbosacral Spinal Cord of Rat Embryos With Anorectal Malformation

BACKGROUND

Bone morphogenetic proteins (BMPs) comprise a highly conserved signaling protein family, which are involved in spinal cord formation, development and differentiation. Malformations of the lumbosacral spinal cord are associated with postoperation complications of anorectal malformation (ARM). However, the mechanism underlying the development of these malformations remains elusive.

MATERIALS AND METHODS

Embryonic rat ARM model induced by ethylenethiourea (ETU) was introduced to investigate BMP7 expression in lumbosacral spinal cord. BMP7 expression was analyzed by immunohistochemical staining, qRT-PCR, and Western blot analysis on embryonic (E) days 16, 17, 19, and 21. The expression of the neuronal marker neurofilament (NF) and pSmad1/5 was determined by immunofluorescence double staining and Western blot analysis during peak BMP7 expression.

RESULTS

BMP7 mRNA (E16, 1.041 ± 0.169 versus 0.758 ± 0.0423, P < 0.05; E17, 1.889 ± 0.444 versus 1.601 ± 0.263, P < 0.05; E19, 2.898 ± 0.434 versus 1.981 ± 0.068, P < 0.01; and E21, 2.652 ± 0.637 versus 1.957 ± 0.09, P < 0.05;) and protein (E16, 1.068 ± 0.065 versus 0.828 ± 0.066, P < 0.01; E17, 1.728 ± 0.153 versus1.4 ± 0.148, P < 0.05; E19, 2.313 ± 0.141 versus 1.696 ± 0.21, P < 0.01; and E21, 2.021 ± 0.13 versus 1.43 ± 0.128, P < 0.01) were downregulated, and their expressions were specifically low in interneurons (IN) located in the dorsal horn of the lumbosacral spinal cord in embryos with ARM. On E19, Western blot analysis revealed reduced P-Smad1/5(1.13 ± 0.08 versus 0.525 ± 0.06, P < 0.01).

CONCLUSIONS

An implication of this study is the possibility that BMP7 downregulation contributes to maldevelopment of the lumbosacral spinal cord during embryogenesis in fetal rats with ARM, indicating that BMP7 may play an important role in ARM pathogenesis and the complications thereof.