Single-cell transcriptomics uncovers cellular architecture and developmental trajectories in hepatoblastoma.

BACKGROUND AND AIMS: Hepatoblastoma (HB) is the predominant type of childhood liver cancer. Treatment options for the clinically advanced HB remain limited. We aimed to dissect the cellular and molecular basis underlying HB oncogenesis and heterogeneity at the single-cell level, which could facilitate a better understanding of HB at both the biological and clinical levels. APPROACH AND RESULTS: Single-cell transcriptome profiling of tumor and paired distal liver tissue samples from five patients with HB was performed. Deconvolution analysis was used for integrating the single-cell transcriptomic profiles with the bulk transcriptomes of our HB cohort of post-neoadjuvant chemotherapy tumor samples. A single-cell transcriptomic landscape of early human liver parenchymal development was established for exploring the cellular root and hierarchy of HB oncogenesis. As a result, seven distinct tumor cell subpopulations were annotated, and an effective HB subtyping method was established based on their compositions. A HB tumor cell hierarchy was further revealed to not only fit with the classical cancer stem cell (CSC) model but also mirror the early human liver parenchymal development. Moreover, FACT inhibition, which could disrupt the oncogenic positive feedback loop between MYC and SSRP1 in HB, was identified as a promising epigenetic-targeted therapeutic strategy against the CSC-like HB1-Pro-like1 subpopulation and its related high-risk "Pro-like1" subtype of HB. CONCLUSIONS: Our findings illustrate the cellular architecture and developmental trajectories of HB via integrative bulk and single-cell transcriptome analyses, thus establishing a resourceful framework for the development of targeted diagnostics and therapeutics in the future.

Gestational age-specific hematological features in preterm infants with necrotizing enterocolitis.

BACKGROUND: This study aimed to investigate gestational age-specific hematological features in preterm infants with necrotizing enterocolitis (NEC) and identify predictive hematological biomarkers for surgical NEC. METHODS: We conducted a retrospective study comparing gestational age (GA)-specific clinical data between medical NEC (m-NEC) and surgical NEC (s-NEC) subgroups, stratified by GA as <28 weeks, 28 ≤ GA < 32 weeks, and 32 ≤ GA < 37 weeks. Multivariate logistic analysis and receiver operating characteristic curve were used to identify the independent predictors of s-NEC. RESULTS: In comparison to m-NEC at NEC onset, s-NEC infants exhibited the following findings: In GA < 28 weeks, s-NEC infants had lower platelet counts. In 28 ≤ GA < 32 weeks, lower absolute lymphocyte counts, and significant percent drop in platelets, lymphocytes, and monocytes were observed. In 32 ≤ GA < 37 weeks, lower absolute lymphocyte counts and significant percent drop in lymphocytes were found. Independent predictors were able to distinguish s-NEC from m-NEC. The area under the curve (AUC) for platelet counts in GA < 28 weeks was 0.880, while C-reactive protein in 28 ≤ GA < 32 weeks had an AUC of 0.889. The AUC for lymphocyte counts in 32 ≤ GA < 37 weeks was 0.892. CONCLUSION: This study identified hematological abnormalities in the development of NEC based on gestational age. Independent predictors may help clinicians distinguish surgical NEC from medical NEC. IMPACT: Necrotizing enterocolitis (NEC) patients with different gestational ages (GA) exhibit different hematological features and independent predictors of surgical NEC differ among different GAs. Our research made the current studies about peripheral hematological features with NEC more complete by analyzing peripheral data collected within 24 h of birth, at day 5-7, day 3-4, day 1-2 before NEC onset, at the time of NEC onset, day 1, day 2, day 3, day 4-5, day 6-7 after NEC onset. Our study is helpful to clinicians in developing a more detailed diagnostic strategy based on GA for the early identification of surgical NEC.

Targeted LC-MS/MS profiling of bile acids reveals primary/secondary bile acid ratio as a novel biomarker for necrotizing enterocolitis.

Bile acids (BAs) are involved in the development of necrotizing enterocolitis (NEC), which mainly occurs in preterm infants. We aim to identify the change of BAs in preterm infants and validate its potential value in the detection of NEC. Targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to measure the plasma BAs in healthy preterm infants and patients with NEC. By analyzing the level of BAs in healthy preterm infants, we found that the plasma concentrations of BAs were related to sex, gestational/postnatal age, birth weight, mode of birth, and feeding type after birth. The plasma levels of TCA, GCA, TCDCA, GCDCA, primary BAs, and total BAs and the primary/secondary BA ratio were decreased, while DCA, UDCA, and secondary BAs were increased in NEC. The primary/secondary BA ratio (cutoff point 62.9) can effectively differentiate NEC from healthy preterm infants, with an AUC of 0.9, a sensitivity of 94.5%, and a specificity of 78.1%. Combining the ratio with high-risk factors of NEC can better distinguish between NEC and control, with an AUC of 0.95. Importantly, significantly lower levels of primary/secondary BA ratio were found in infants with surgical NEC than in nonsurgical NEC cases. The cutoff point of 28.7 identified surgical NEC from nonsurgical NEC with sensitivity and specificity of 76.9% and 100%. Thus, our study identified that the primary/secondary BA ratio in the plasma can differentiate NEC from healthy preterm infants and effectively differentiate the surgical NEC from nonsurgical NEC. Therefore, LC-MS/MS was expected to be a novel measurement platform used to distinguish infants who are most in need of close monitoring or early surgical intervention.

Effectiveness of preoperative ultrasonography in predicting metachronous contralateral inguinal hernia in children: a single-arm prospective study using a historical control for comparison.

PURPOSE: To analyze the value of ultrasonography in predicting metachronous contralateral inguinal hernia (MCIH) and diagnosing contralateral persistent processus vaginalis (CPPV) in children with unilateral inguinal hernia, a prospective study was conducted. METHODS: All participants underwent a preoperative ultrasound on the contralateral groin. Patients in group A1 received operating procedure according to ultrasound results (patients with negative contralateral US results received hernia repair on the affected side), and patients in group A2 received operation according to laparoscopic results (patients received hernia repair and CPPV ligation). All patients were followed up 2 years and compared to a historical control (group B) who underwent open hernia repair only on the affected side regardless of contralateral US results. RESULTS: In groups A1 and A2, laparoscopic exploration revealed the presence of a CPPV in 490 cases. Ultrasound was found to be accurate in 104 out of the 490 cases with four false-positive and 386 false-negative results. This yielded an accuracy of 59.3%, a sensitivity of 21.2%, and a specificity of 99.2%. 10 patients in group A1, and 74 patients in group B developed MCIH. The accuracy, sensitivity, and specificity of the value of ultrasonography in predicting MCIH were 89.3%, 52.4%, and 92.5%, respectively. CONCLUSIONS: Preoperative ultrasonography of the contralateral groin is currently unable to accurately detect CPPV, but it appears to be a promising method in predicting MCIH by using rigorous diagnosing criteria.

Endoscopic Balloon Dilatation-Based Membrane Resection for Membranous Duodenal Stenosis: A Feasibility and Safety Study (With Video).

OBJECTIVES: Surgery is generally considered as the first-line therapy for membranous duodenal stenosis (MDS) in children. However, abdominal surgery leaves permanent scars and may even cause intestinal adhesion. Therefore, an effective, safe, and minimally invasive method is urgently needed. This study aimed to evaluate the safety, efficacy, and feasibility of endoscopic balloon dilatation-based membrane resection (EBD-MR) to treat MDS in children. METHODS: We retrospectively reviewed patients with MDS treated with EBD-MR in Shanghai Children's Hospital from May 2016 to August 2021. Primary study outcome was clinical success, defined as weight gain and complete remission of vomiting, without the need for repeat endoscopic or surgical intervention during follow-up. Secondary outcomes included technical success, diameter changes of the membrane opening, and adverse events. RESULTS: Nineteen children (9 females, mean age 14.5 ± 11.2 months) received endoscopic treatment for MDS, and clinical success was achieved in 18 of 19 patients (94.7%). No bleeding, perforation, and jaundice occurred. Diameters of the membrane opening increased from 2.97 ± 2.87 mm to 9.78 ± 1.27 mm after the treatment, symptoms of vomiting did not reappear during 10-73 months of follow-up, and body mass index of the children increased from 14.9 ± 2.2 kg/m 2 (pre-operation) to 16.2 ± 3.7 kg/m 2 (6 months after operation). One patient required surgical revision because of existence of a second web; three patients received 2-3 sessions of endoscopic treatment to obtain the final remission. CONCLUSIONS: The EBD-MR technique is safe, effective, and feasible for MDS, which provided an excellent alternative to surgical management for the disease in pediatric patients.

Misdiagnosis of scrotal and retroperitoneal lymphangioma in children.

BACKGROUND: Scrotal and retroperitoneal lymphangioma (SRL) in children is relatively rare and its clinical symptoms are usually difficult to distinguish from other conditions such as hydrocele and incarcerated inguinal oblique hernia. This study aimed to explore the clinical diagnosis and treatment of abdominal scrotal lymphangioma in children, and thus, to increase our understandings of this disease in clinical practice. METHOD: This study enrolled nine boys, aged 1-10, who were admitted to Shanghai Children's Hospital from January 2019 to December 2020 and who were finally confirmed with lymphangioma in the inguinal area. The clinical manifestations, diagnosis, and treatment of these children were analyzed retrospectively. The length of diagnostic process ranged from 3 weeks to 20 months. We also reviewed other cases of initially misdiagnosed cases of SRL in English publications from 2000 to 2022. RESULTS: The nine cases were misdiagnosed as hydrocele, hematoma, or inguinal hernia. Three patients received intracystic injection of bleomycin, three underwent laparoscopic mass resection, and three underwent resection of the inguinal lymphangioma under direct vision. Postoperative pathological analysis of the surgical specimens confirmed the diagnosis of benign cystic lesions and lymphangioma. Meanwhile, among the 14 cases of SRL in literature review, eight were misdiagnosed. Six were initially diagnosed as hydrocele, one as inguinal oblique hernia, and one as testicular tumor, all of which underwent ultrasonography scans. All cases were confirmed as lymphangioma after pathological examination. CONCLUSION: The non-specific clinical manifestations may contribute to the misdiagnosis of scrotal masses in children. A detailed and accurate medical history, careful physical examination, and imaging findings are important factors contributing to the preoperative differential diagnosis of scrotal lumps in children, but the final diagnosis is based on pathological examination.

Bifidobacterium alters the gut microbiota and modulates the functional metabolism of T regulatory cells in the context of immune checkpoint blockade.

Immune checkpoint-blocking antibodies that attenuate immune tolerance have been used to effectively treat cancer, but they can also trigger severe immune-related adverse events. Previously, we found that Bifidobacterium could mitigate intestinal immunopathology in the context of CTLA-4 blockade in mice. Here we examined the mechanism underlying this process. We found that Bifidobacterium altered the composition of the gut microbiota systematically in a regulatory T cell (Treg)-dependent manner. Moreover, this altered commensal community enhanced both the mitochondrial fitness and the IL-10-mediated suppressive functions of intestinal Tregs, contributing to the amelioration of colitis during immune checkpoint blockade.

DNA Methylome Mapping Identifies Epigenetic Abnormalities in Intestinal Lymphocyte Regulation in Human Necrotizing Enterocolitis.

BACKGROUND: Epigenetic changes occur in response to environmental factors during the pathogenesis of necrotizing enterocolitis (NEC) in animal models, but the DNA methylation signature in human patients with NEC has not been examined. AIM: To illustrate the signature and function of DNA methylation in the intestine of human NEC. METHODS: DNA methyltransferases (DNMTs) were compared between intestinal tissue with NEC and control. Genome-wide DNA methylation was analyzed by reduced representation bisulfite sequencing (RRBS). The biological functions of the potential methylation regulated genes were analyzed by Gene Ontology. Gene methylation and expression were confirmed by bisulfite genomic sequencing (BGS) and RT-qPCR. RESULTS: By screening the expression of DNMTs, we identified a marked reduction in DNMT3A at both the mRNA and protein levels in NEC. Genome-wide variation of DNA methylation was detected in NEC lesions. The CG methylation level in almost all unique regions except CpG islands (CGIs) was lower in NEC compared with control. A total of 287 differentially methylated regions (DMRs) were identified across the whole genome in NEC, 123 of them are located on the CGI in the promoter. The DMR-associated genes were linked to intestinal epithelial permeability, platelet aggregation, and lymphocyte proliferation. Four genes (ZNF335, MPL, RASAL3, and KDM6A) with roles in the regulation of lymphocytes that may predispose the intestine to imbalanced immune processes were further confirmed to be hypermethylated and transcriptionally downregulated. CONCLUSIONS: These findings underscore the novel relationship between epigenetic changes and lymphocyte regulation in human NEC, which may have potential diagnostic and therapeutic relevance for NEC.

DRG1 Maintains Intestinal Epithelial Cell Junctions and Barrier Function by Regulating RAC1 Activity in Necrotizing Enterocolitis.

BACKGROUND: An immature intestine is a high-risk factor for necrotizing enterocolitis (NEC), which is a serious intestinal disease in newborns. The regulation of developmentally regulated GTP-binding protein 1 (DRG1) during organ development suggests a potential role of DRG1 in the maturation process of the intestine. AIM: To illustrate the function of DRG1 during the pathogenesis of NEC. METHODS: DRG1 expression in the intestine was measured using immunohistochemistry and q-PCR. Immunoprecipitation coupled with mass spectrometry was used to identify the interacting proteins of DRG1. The biological functions of the potential interactors were annotated with the Database for Annotation, Visualization and Integrated Discovery. Caco2 and FHs74Int cells with stable DRG1 silencing or overexpression were used to investigate the influence of DRG1 on cell junctions and intestinal barrier permeability and to elucidate the downstream mechanism. RESULTS: DRG1 was constitutively expressed during the intestinal maturation process but significantly decreased in the ileum in the context of NEC. Protein interaction analysis revealed that DRG1 was closely correlated with cell junctions. DRG1 deficiency destabilized the E-cadherin and occludin proteins near the cell membrane and increased the permeability of the epithelial cell monolayer, while DRG1 overexpression prevented lipopolysaccharide-induced disruption of E-cadherin and occludin expression and cell monolayer integrity. Further investigation suggested that DRG1 maintained cell junctions, especially adherens junctions, by regulating RAC1 activity, and RAC1 inhibition with NSC23766 attenuated intestinal injury and led to improved barrier integrity in experimental NEC. CONCLUSIONS: Our findings illustrate the mechanism underlying the effect of DRG1 deficiency on epithelial cell permeability regulation and provide evidence supporting the application of RAC1 inhibitors for protection against NEC.

Role of image-defined risk factors in predicting surgical complications of localized neuroblastoma.

PURPOSE: To explore the relationship between image-defined risk factors and surgical complications of localized neuroblastoma. METHODS: We retrospectively evaluated 84 patients who met the inclusion criteria at our hospitals between June 2014 and June 2019. Patients' clinic data were collected and the common terminology criteria for adverse events were used to categorize complications as major (grade 3-4) or minor (grade 1-2). RESULTS: Four (11.8%) out of 34 stage L1 patients and 15 (30.0%) out of 50 stage L2 patients had surgical complications (P < 0.05). Seventy patents underwent primary surgery, including all stage L1 patients and 36 stage L2 patients. There were no significant differences between the two groups regarding surgical complications or major surgical complications. Among stage L2 patients, 2 (5.6%) out of 36 who underwent primary surgery and 2 (14.3%) out of 14 who underwent secondary surgery had major surgical complications (P < 0.05). Complete tumor resection was achieved in 18 (50%) and 7 (50%) patients in each group (P > 0.05). The mean numbers of IDRFs were 2.06 and 4.29, respectively (P < 0.05). CONCLUSIONS: Localized neuroblastoma patients with IDRFs have a greater surgical risk. And the number of IDRFs is not ignorable, especially in predicting major surgical complications.

The role of preoperative imaging and tumor markers in predicting malignant ovarian masses in children.

PURPOSE: To investigate the clinicopathololgic characteristics and the predicting value of preoperative imaging and tumor markers in children with ovarian masses. METHODS: Patients admitted in Shanghai children's hospital with ovary neoplasms between 2010.01 and 2015.12 were retrospectively analyzed. The medical records including age at operation, presentation of symptoms and signs, tumor marker, imaging, pathology, tumor diameter and surgical choice were reviewed. All data were analyzed using SPSS 17.0 RESULTS: A total of 139 patients were included, among which 116 were benign neoplasms and 23 malignant tumors. There was significance difference relation with the tumor diameter, character, torsion and tumor markers, but not the age, position, calculi, and symptoms. The risk factors include tumor diameters ≥ 10 cm, the odds ratio (OR) was 11, 95% confidence interval (CI) was 3-36, solid/complex tumor (OR 6, 95% CI 2, 14) and positive in tumor markers (OR 84, 95% CI 20, 345). Among the patients with benign neoplasms, 77 of them had laparoscopic ovarian cystectomy while 23 patients with malignant tumors had salpingo-oophorectomy and omentum resection. CONCLUSION: Preoperative imaging and tumor markers could help identifying the malignant ovarian masses in children. If tumor diameter ≥ 10 cm, solid/complex in imaging and tumor markers abnormal, a radical resection is mandatory; otherwise, an ovarian-sparing surgery is recommended.

Reoperation After Cyst Excision with Hepaticojejunostomy for Choledochal Cysts: Our Experience in 18 Cases.

BACKGROUND Complete cyst excision with biliary reconstruction is the treatment of choice for choledochal cyst (CC). The aim of this article is to review our experience in patients who underwent reoperation between January 1995 and December 2014. MATERIAL AND METHODS The records of 18 patients (female/male, 15/3) were retrospectively analyzed including age, sex, cyst type, initial procedure, lab and imaging findings, indications for reoperation, intraoperative findings, and results of reoperation. The median follow-up period was 6 years. RESULTS The rate of reoperation in this study was about 6.8%. Eighteen patients (7 type Ia, 2Ic, 9 IV-A) developed severe postoperative complications and required surgical intervention. The median time interval from primary surgery to reoperation was 19.5 months (range, 3 days to 8 years). Two early complications required surgery due to anastomotic bile leakage and intussusception. Sixteen late complications occurred, including 3 intrahepatic bile duct stenosis with calculi, 5 anastomotic strictures with/without stones, 4 intrapancreatic cyst remnants, 3 adhesive bowel obstructions, and 1 internal hernia. For patients with persistent dilatation of the intrahepatic bile duct or anastomotic stricture, removal of stones and revision of hepaticojejunostomy were performed, with additional hepatic ductoplasty when necessary. Radical excision of the dilated cystic remnant in the head of pancreas was performed in 4 patients, with 1 needing additional pancreaticojejunostomy procedure. No deaths occurred. Sixteen patients recovered uneventfully after reoperation, and 2 wound infections developed. CONCLUSIONS A wide hepaticojejunostomy with/without ductoplasty is essential to prevent cholangitis, anastomotic stricture, and calculi formation. Complete cyst excision, including the intrapancreatic portion, should be meticulously pursued.

Fn14 hepatic progenitor cells are associated with liver fibrosis in biliary atresia.

PURPOSE: The liver in biliary atresia (BA) is characterized by progressing fibrosis which is promoted by unclear reasons. We aimed to understand the factors influencing liver fibrosis. This study hypothesized that HPCs (hepatic progenitor cells) are activated and associated with liver fibrosis in biliary atresia. METHODS: Liver samples from biliary atresia patients are as BA group, and the normal liver derived from hepatoblastoma infants during operation are control group. The extent of fibrosis in liver samples was blindly evaluated by two experienced pathologists depending on Ishak system. The BA liver samples were divided into mild liver fibrosis group (grade I-IV, BAa) and severe liver fibrosis group (grade V-VI, BAb) to detect Fn14 protein expression. RESULTS: In mRNA level, Fn14 expression was 21.23 ± 8.3 vs. 1.00 ± 0.17, p = 0.023 < 0.05 and CD133 expression was 6.02 ± 2.16 vs. 1.14 ± 0.75, p = 0.008 < 0.01 between BA group and control group. Fn14 cells co-expressed the progenitor marker CD133 in liver, and activated in BA. Fn14 andα-SMA were co-location in fibrous area in liver. Compared to the control group, Fn14, CD133, and α-SMA protein expression were 2.10 ± 0.53 vs. 0.97 ± 0.2, p = 0.001, 2.23 ± 0.57 vs. 1.00 ± 0.03, p = 0.000, 4.96 ± 2.4 vs. 1.00 ± 0.22, p = 0.001. The Fn14 protein expression was 2.60 ± 0.35 vs. 1.86 ± 0.42, p = 0.012, between BAb and BAa group. CONCLUSION: Fn14 cells, which co-express the progenitor marker CD133 in liver, are HPCs and activated in BA. Fn14 + HPCs are associated with liver fibrosis in BA.

Human ß-defensin-3 promotes intestinal epithelial cell migration and reduces the development of necrotizing enterocolitis in a neonatal rat model.

BACKGROUND: The aim of this study was to investigate the effects of human ß-defensin-3 (hBD3) on intestinal wound healing and in a neonatal rat model of necrotizing enterocolitis (NEC). METHODS: Enterocyte migration and proliferation were detected in vitro and in vivo. The role of chemokine receptor CCR6 and its downstream signaling pathway was assessed. Newborn Sprague-Dawley rats were randomly divided into four groups: Control+NS, Control+hBD3, NEC+NS, and NEC+hBD3. Body weight, histological score, survival time, cytokines expression, and mucosal integrity were evaluated. RESULTS: hBD3 could stimulate enterocyte migration, but not proliferation, both in cultured enterocytes and in the NEC model. Neutralizing antibody and small interfering RNA confirmed this stimulatory effect was mediated by CCR6. Furthermore, hBD3 induced Rho activation, myosin light chain 2 phosphorylation, and F-actin accumulation. The bactericidal activity of hBD3 was maintained throughout a broad pH range. Strikingly, hBD3 administration decreased the incidence of NEC, increased the survival rate, and reduced the severity of NEC. Moreover, hBD3 reduced the proinflammatory cytokines expression in ileum and serum and preserved the intestinal barrier integrity. CONCLUSION: This study provided evidence that the antimicrobial peptide hBD3 might participate in intestinal wound healing by promoting enterocyte migration and show beneficial effects on newborn rats with NEC.

A study of two Chinese patients with tetrasomy and pentasomy 15q11q13 including Prader-Willi/Angelman syndrome critical region present with developmental delays and mental impairment.

BACKGROUND: The proximal chromosome 15q is prone to unequal crossover, leading to rearrangements. Although 15q11q13 duplications are common in patients with developmental delays and mental impairment, 15q aneusomies resulting in greater or equal to 4 copies of 15q11q13 are rare and no pentasomy 15q11q13 has been reported in the literature. Thus far, all reported high copy number 15q11q13 cases are from the West populations and no such study in Chinese patients have been documented. Dosage-response pattern of high copy number 15q11q13 on clinical presentations is still a subject for further study. CASE PRESENTATION: In this study, we characterized two Han Chinese patients with high copy number 15q11q13. Using chromosome banding, high resolution SNP-based cytogenomic array, Fluorescence in situ hybridization, and PCR-based microsatellite analysis, we identified two patients with tetrasomy 15q11q13 and pentasomy 15q11q13. Both 15q11q13 aneusomies resulted from a maternally inherited supernumerary marker chromosome 15, and each was composed of two different sized 15q11q13 segments covering the Prader-Willi/Angelman critical region: one being about 10 Mb with breakpoints at BP1 and BP5 regions on 15q11 and 15q13, respectively, and another about 8 Mb in size with breakpoints at BP1 and BP4 regions on 15q. Both patients presented with similar clinical features that included neurodevelopmental delays, mental impairment, speech and autistic behavior, and mild dysmorphism. The patient with pentasomy 15q11q13 was more severely affected than the patient with tetrasomy 15q11q13. Low birth weight was noted in patient with pentasomy 15q1q13. CONCLUSIONS: To the best of our knowledge, this is the first case of pentasomy 15q11q13 and the first study of high copy number 15q11q13 in Han Chinese patients. Our findings demonstrate that patients with tetrasomy and pentasomy of chromosome 15q11q13 share similar spectrum of phenotypes reported in other high copy number 15q11q13 patients in the West, and positive correlation between 15q11q13 copy number and degree of severity of clinical phenotypes. Low birth weight observed in the pentasomy 15q11q13 patient was not reported in other patients with high copy number 15q11q13. Additional studies would be necessary to further characterize high copy number 15q11q13 aneusomies.

Pathogenicity of p.Phe147del in RET in familial Hirschsprung's disease.

OBJECTIVE: The study aimed to explore the pathogenicity of RET p.Phe147del in a Hirschsprung'irschspru (HSCR) family and facilitate the deeper understanding of HSCR families. METHODS: Whole-exome sequencing (WES) was performed to decipher a HSCR family. We used a "GlycoEP" tool to analyze RET protein glycosylation. A series of molecular biological approaches including mutated plasmid construction, cell transfection, polymerase chain reaction, immunofluorescence and immunoblotting were introduced to determine the mutation status and altered expression of RET as well as its related genes or proteins. MG132 was applied to analyze the mechanism of mutated RET. RESULTS: WES and Sanger results revealed that p.Phe147del in-frame mutation (IM) was a potential pathogenetic factor for familial HSCR. Moreover, the IM led to disrupted N-glycosylation of RET accompanied with protein structural change, resulting in the decreased transcriptional and protein level of RET, CCND1, VEGF and BCL2, and the decreased protein level of phosphorylated ERK and STAT3. Further studies revealed that the IM-evoked RET decline was reversed by inhibiting proteosome in a dose dependent manner, thus suggesting that the decrease in intracellular RET protein levels interrupted the transportation of RET protein from the cytoplasm to the cell surface. CONCLUSION: The newly found p.Phe147del IM of RET is pathogenic to familial HSCR and it disrupts RET structure and abundance via the proteasome pathway, representing evidence for the early prevention, clinical diagnosis and treatment of HSCR.

RNA N6-methyladenosine reader IGF2BP3 interacts with MYCN and facilitates neuroblastoma cell proliferation.

Neuroblastoma (NB) is a kind of typical life-threatening extracranial tumor in children. N6-methyladenosine (m6A) modification is closely related to multiple cancer pathological processes. Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) is a top-ranked prognostic risk gene in NB; however, its function is uncertain. The expression of m6A-associated enzymes in patients with NB was analyzed using the Gene Expression Omnibus (GEO) and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. The IGF2BP3 level in NB cell lines and primary samples was tested using quantitative real-time polymerase chain reaction (qRT-PCR), western blot method, and immunohistochemical analysis. The IGF2BP3 function in cell proliferation was clarified based on many functional in vitro and in vivo experiments. The interaction between IGF2BP3 and N-myc was researched via RNA immunoprecipitation (RIP), m6A RNA immunoprecipitation (MeRIP), and chromatin immunoprecipitation (ChIP) assays. The 16 m6A-regulated enzymes in NB were researched, and the result indicated that IGF2BP3 overexpression was related to cancer progression, COG risk, and survival based on the GEO and TARGET databases. Besides, the IGF2BP3 and MYCN levels were positively correlated. IGF2BP3 expression levels increased in MYCN-amplified NB clinical samples and cells. Knockdown of IGF2BP3 inhibited N-myc expression and NB cell proliferation in vitro and in vivo. IGF2BP3 regulates MYCN RNA stability by modifying m6A. In addition, we demonstrated that N-myc is a transcription factor that directly promotes IGF2BP3 expression in NB cells. IGF2BP3 regulates the proliferation of NB cells via m6A modification of MYCN. N-myc also acts as a transcription factor that regulates IGF2BP3 expression. A positive feedback loop between IGF2BP3 and N-myc facilitates NB cell proliferation.