Integrative analysis of microRNA and mRNA expression profiles in fetal rat model with anorectal malformation

Growth of the prefrontal cortical glioblastoma altered cognitive and emotional behaviors via mediating miRNAs and GABA-A receptor signaling pathways in rats

The present study investigated the impact of GABAergic signaling and miRNA expression on glioblastoma multiforme (GBM) growth within the medial prefrontal cortex (mPFC) and its associated cognitive and emotional impairments. The implantation of C6 cells into the mPFC induced GBM in this brain region (referred to as the mPFC-GBM) in male Wistar rats via stereotaxic surgery, as confirmed by Magnetic Resonance Imaging (MRI), and Hematoxylin and Eosin (H&E) staining. Repeated microinjections of muscimol, a potent GABAA receptor agonist, directly into the mPFC-GBM (1 µg/rat/2.5 μl) following tumor induction decreased tumor volume and weight, resulting in an increased survival rate. Conversely, a higher dose of muscimol (6 µg/rat/2.5 μl) increased tumor size and reduced survival. Behavioral alterations induced by GBM, including anxiety-like responses, exploratory behaviors, locomotor activity, and memory formation, were assessed using anxiety-like behavior task, the hole-board test, and the novel object recognition test. Muscimol treatment dose-dependently affected these behaviors in the animals with the mPFC-GBM, bringing their performance with that of the sham group at the dose of 1 µg/rat/2.5 μl. Changes in specific miRNAs expressions, including miR-208, -290-295, -345, -743 and -802 were associated with the growth of the mPFC-GBM under muscimol treatment. These findings suggest that GBM growth into the mPFC profoundly impacts cognitive and emotional behaviors which can be improved by muscimol treatment. Considering that the expression levels of targeted miRNAs could be influenced by the growth of the mPFC-GBM, both with or without muscimol treatment, these non-coding RNAs might serve as potential biomarkers for GBM.

Intra-amniotic delivery of tropomodulin 3 rescues cell apoptosis induced by miR-200b-3p upregulation via non-canonical nuclear factor kappa B pathways in ethylene thiourea induced anorectal malformations fetal rat

Ethylene thiourea (ETU), a metabolite of the fungicide ethylene bisdithiocarbamate (EBDC), has received great concern because of its harmful effects. ETU-induced anorectal malformations (ARMs) in rat models have been reported and widely used in the study of ARMs embryogenesis. Dysplasia of the lumbosacral spinal cord (LSSC), pelvic floor muscles (PFMs), and hindgut (HG) during intrauterine life affects postoperative defecation in patients with ARMs. However, the underlying toxic effects of ETU and pathological mechanisms in the three defecation-related tissues of fetuses with ARMs have not been reported. Thus, this study aimed to elucidate the molecular mechanisms involved in ARMs, with a focus on the dysregulation of miR-200b-3p and its downstream target tropomodulin 3 (TMOD3). The mRNA and protein levels of miR-200b-3p and TMOD3 in LSSC, PFMs, and HG of fetal rats with ARMs were evaluated by reverse transcription quantitative polymerase chain reaction and Western blotting (WB) on embryonic day 17 (E17). Further, a dual-luciferase reporter assay confirmed their targeting relationship. Gene silencing and overexpression of miR-200b-3p and TMOD3 were performed to verify their functions in HEK-293 T cells. Fetal rats with ARMs also received intra-amniotic microinjection of Ad-TMOD3 on E15, and key molecules in nuclear factor kappa (NF-κB) signaling and apoptosis were evaluated by WB on E21. Abnormally high levels of miR-200b-3p inhibited TMOD3 expression by binding with its 3'-untranslated region, leading to the activation of the non-canonical NF-κB signaling pathway, which is critical in the maldevelopment of LSSC, PFMs, and HG in ARMs rats. Furthermore, miR-200b-3p triggered apoptosis by directly targeting TMOD3. Notably, intra-amniotic Ad-TMOD3 microinjection revealed that the upregulation of TMOD3 expression mitigates the effects of miR-200b-3p on the activation of non-canonical NF-κB signaling and apoptosis in fetal rat model of ARMs. A novel miR-200b-3p/TMOD3/non-canonical NF-κB signaling axis triggered the massive apoptosis in LSSC, PFMs, and HG of ARMs, which was restored by the intra-amniotic injection of Ad-TMOD3 during embryogenesis. Our results indicate the potential of TMOD3 as a treatment target to restore defecation.

Rack1-mediated ferroptosis affects hindgut development in rats with anorectal malformations: Spatial transcriptome insights

Anorectal malformation (ARM), a common congenital anomaly of the digestive tract, is a result of insufficient elongation of the urorectal septum. The cytoplasmic protein Receptor of Activated C-Kinase 1 (Rack1) is involved in embryonic neural development; however, its role in embryonic digestive tract development and ARM formation is unexplored. Our study explored the hindgut development and cell death mechanisms in ARM-affected rats using spatial transcriptome analysis. We induced ARM in rats by administering ethylenethiourea via gavage on gestational day (GD) 10. On GDs 14-16, embryos from both normal and ARM groups underwent spatial transcriptome sequencing, which identified key genes and signalling pathways. Rack1 exhibited significant interactions among differentially expressed genes on GDs 15 and 16. Reduced Rack1 expression in the ARM-affected hindgut, verified by Rack1 silencing in intestinal epithelial cells, led to increased P38 phosphorylation and activation of the MAPK signalling pathway. The suppression of this pathway downregulated Nqo1 and Gpx4 expression, resulting in elevated intracellular levels of ferrous ions, reactive oxygen species (ROS) and lipid peroxides. Downregulation of Gpx4 expression in the ARM hindgut, coupled with Rack1 co-localisation and consistent mitochondrial morphology, indicated ferroptosis. In summary, Rack1, acting as a hub gene, modulates ferrous ions, lipid peroxides, and ROS via the P38-MAPK/Nqo1/Gpx4 axis. This modulation induces ferroptosis in intestinal epithelial cells, potentially influencing hindgut development during ARM onset.

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.

Peripheral Circulating Exosomal miRNAs Potentially Contribute to the Regulation of Molecular Signaling Networks in Aging

People are living longer than ever. Consequently, they have a greater chance for developing a functional impairment or aging-related disease, such as a neurodegenerative disease, later in life. Thus, it is important to identify and understand mechanisms underlying aging as well as the potential for rejuvenation. Therefore, we used next-generation sequencing to identify differentially expressed microRNAs (miRNAs) in serum exosomes isolated from young (three-month-old) and old (22-month-old) rats and then used bioinformatics to explore candidate genes and aging-related pathways. We identified 2844 mRNAs and 68 miRNAs that were differentially expressed with age. TargetScan revealed that 19 of these miRNAs are predicated to target the 766 mRNAs. Pathways analysis revealed signaling components targeted by these miRNAs: mTOR, AMPK, eNOS, IGF, PTEN, p53, integrins, and growth hormone. In addition, the most frequently predicted target genes regulated by these miRNAs were EIF4EBP1, insulin receptor, PDK1, PTEN, paxillin, and IGF-1 receptor. These signaling pathways and target genes may play critical roles in regulating aging and lifespan, thereby validating our analysis. Understanding the causes of aging and the underlying mechanisms may lead to interventions that could reverse certain aging processes and slow development of aging-related diseases.