Human genetic defects in SRP19 and SRPRA cause severe congenital neutropenia with distinctive proteome changes.

The mechanisms of coordinated changes in proteome composition and their relevance for the differentiation of neutrophil granulocytes are not well studied. Here, we discover 2 novel human genetic defects in signal recognition particle receptor alpha (SRPRA) and SRP19, constituents of the mammalian cotranslational targeting machinery, and characterize their roles in neutrophil granulocyte differentiation. We systematically study the proteome of neutrophil granulocytes from patients with variants in the SRP genes, HAX1, and ELANE, and identify global as well as specific proteome aberrations. Using in vitro differentiation of human induced pluripotent stem cells and in vivo zebrafish models, we study the effects of SRP deficiency on neutrophil granulocyte development. In a heterologous cell-based inducible protein expression system, we validate the effects conferred by SRP dysfunction for selected proteins that we identified in our proteome screen. Thus, SRP-dependent protein processing, intracellular trafficking, and homeostasis are critically important for the differentiation of neutrophil granulocytes.

Current advances in human-induced pluripotent stem cell-based models and therapeutic approaches for congenital heart disease.

Congenital heart disease (CHD) represents a significant risk factor with profound implications for neonatal survival rates and the overall well-being of adult patients. The emergence of induced pluripotent stem cells (iPSCs) and their derived cells, combined with CRISPR technology, high-throughput experimental techniques, and organoid technology, which are better suited to contemporary research demands, offer new possibilities for treating CHD. Prior investigations have indicated that the paracrine effect of exosomes may hold potential solutions for therapeutic intervention. This review provides a summary of the advancements in iPSC-based models and clinical trials associated with CHD while elucidating potential therapeutic mechanisms and delineating clinical constraints pertinent to iPSC-based therapy, thereby offering valuable insights for further deliberation.

Mammalian VPS45 orchestrates trafficking through the endosomal system.

Vacuolar protein sorting 45 homolog (VPS45), a member of the Sec1/Munc18 (SM) family, has been implicated in the regulation of endosomal trafficking. VPS45 deficiency in human patients results in congenital neutropenia, bone marrow fibrosis, and extramedullary renal hematopoiesis. Detailed mechanisms of the VPS45 function are unknown. Here, we show an essential role of mammalian VPS45 in maintaining the intracellular organization of endolysosomal vesicles and promoting recycling of cell-surface receptors. Loss of VPS45 causes defective Rab5-to-Rab7 conversion resulting in trapping of cargos in early endosomes and impaired delivery to lysosomes. In this context, we demonstrate aberrant trafficking of the granulocyte colony-stimulating factor receptor in the absence of VPS45. Furthermore, we find that lack of VPS45 in mice is not compatible with embryonic development. Thus, we identify mammalian VPS45 as a critical regulator of trafficking through the endosomal system and early embryogenesis of mice.

Rehabilitation of long-term mandibular defects by whole-process digital fibula flap combining with implants: A case report.

Currently, the gold standard and workhorse in mandibular reconstruction is the free vascularized fibula flap. Particularly for patients who have had mandibulectomy for a long time, it is still difficult to precisely reconstruct the mandibular contour and successfully restore the patient's chewing function and esthetics. For the restoration and rehabilitation of long-term mandibular abnormalities, three-dimensional (3D) virtual surgical planning (VSP) and 3D-printed surgical guides are essential. Digital design and manufacturing were used to improve the accuracy of prostheses and facilitate occlusal reconstruction. Therefore, equipped with the methods of 3D VSP, 3D-printed surgical guides, free vascularized fibular flap, and immediate dental implants, this clinical report provides a feasible solution for mandibular reconstruction.

Germline intergenic duplications at Xq26.1 underlie Bazex-Dupré-Christol basal cell carcinoma susceptibility syndrome.

BACKGROUND: Bazex-Dupré-Christol syndrome (BDCS; MIM301845) is a rare X-linked dominant genodermatosis characterized by follicular atrophoderma, congenital hypotrichosis and multiple basal cell carcinomas (BCCs). Previous studies have linked BDCS to an 11·4-Mb interval on chromosome Xq25-q27.1. However, the genetic mechanism of BDCS remains an open question. OBJECTIVES: To investigate the genetic aetiology and molecular mechanisms underlying BDCS. METHODS: We ascertained multiple individuals from eight unrelated families affected with BDCS (F1-F8). Whole-exome (F1 and F2) and genome sequencing (F3) were performed to identify putative disease-causing variants within the linkage region. Array comparative genomic hybridization and quantitative polymerase chain reaction (PCR) were used to explore copy number variations, followed by long-range gap PCR and Sanger sequencing to amplify the duplication junctions and to define the head-tail junctions. Hi-C was performed on dermal fibroblasts from two affected individuals with BDCS and one control. Public datasets and tools were used to identify regulatory elements and transcription factor binding sites within the minimal duplicated region. Immunofluorescence was performed in hair follicles, BCCs and trichoepitheliomas from patients with BDCS and sporadic BCCs. The ACTRT1 variant c.547dup (p.Met183Asnfs*17), previously proposed to cause BDCS, was evaluated with t allele frequency calculator. RESULTS: In eight families with BDCS, we identified overlapping 18-135-kb duplications (six inherited and two de novo) at Xq26.1, flanked by ARHGAP36 and IGSF1. Hi-C showed that the duplications did not affect the topologically associated domain, but may alter the interactions between flanking genes and putative enhancers located in the minimal duplicated region. We detected ARHGAP36 expression near the control hair follicular stem cell compartment, and found increased ARHGAP36 levels in hair follicles in telogen, in BCCs and in trichoepitheliomas from patients with BDCS. ARHGAP36 was also detected in sporadic BCCs from individuals without BDCS. Our modelling showed the predicted maximum tolerated minor allele frequency of ACTRT1 variants in control populations to be orders of magnitude higher than expected for a high-penetrant ultra-rare disorder, suggesting loss of function of ACTRT1 variants to be an unlikely cause for BDCS. CONCLUSIONS: Noncoding Xq26.1 duplications cause BDCS. The BDCS duplications most likely lead to dysregulation of ARHGAP36. ARHGAP36 is a potential therapeutic target for both inherited and sporadic BCCs. What is already known about this topic? Bazex-Dupré-Christol syndrome (BDCS) is a rare X-linked basal cell carcinoma susceptibility syndrome linked to an 11·4-Mb interval on chromosome Xq25-q27.1. Loss-of-function variants in ACTRT1 and its regulatory elements were suggested to cause BDCS. What does this study add? BDCS is caused by small tandem noncoding intergenic duplications at chromosome Xq26.1. The Xq26.1 BDCS duplications likely dysregulate ARHGAP36, the flanking centromeric gene. ACTRT1 loss-of-function variants are unlikely to cause BDCS. What is the translational message? This study provides the basis for accurate genetic testing for BDCS, which will aid precise diagnosis and appropriate surveillance and clinical management. ARHGAP36 may be a novel therapeutic target for all forms of sporadic basal cell carcinomas.

Human RIPK1 deficiency causes combined immunodeficiency and inflammatory bowel diseases.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a critical regulator of cell death and inflammation, but its relevance for human disease pathogenesis remains elusive. Studies of monogenic disorders might provide critical insights into disease mechanisms and therapeutic targeting of RIPK1 for common diseases. Here, we report on eight patients from six unrelated pedigrees with biallelic loss-of-function mutations in RIPK1 presenting with primary immunodeficiency and/or intestinal inflammation. Mutations in RIPK1 were associated with reduced NF-κB activity, defective differentiation of T and B cells, increased inflammasome activity, and impaired response to TNFR1-mediated cell death in intestinal epithelial cells. The characterization of RIPK1-deficient patients highlights the essential role of RIPK1 in controlling human immune and intestinal homeostasis, and might have critical implications for therapies targeting RIPK1.

miR-191 modulates B-cell development and targets transcription factors E2A, Foxp1, and Egr1.

The interdependence of posttranscriptional gene regulation via miRNA and transcriptional regulatory networks in lymphocyte development is poorly understood. Here, we identified miR-191 as direct upstream modulator of a transcriptional module comprising the transcription factors Foxp1, E2A, and Egr1. Deletion as well as ectopic expression of miR-191 resulted in developmental arrest in B lineage cells, indicating that fine tuning of the combined expression levels of Foxp1, E2A, and Egr1, which in turn control somatic recombination and cytokine-driven expansion, constitutes a prerequisite for efficient B-cell development. In conclusion, we propose that miR-191 acts as a rheostat in B-cell development by fine tuning a key transcriptional program.

A novel missense mutation of RPGR identified from retinitis pigmentosa affects splicing of the ORF15 region and causes loss of transcript heterogeneity.

Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene, are the major cause of X-linked retinitis pigmentosa (RP), in which exon open reading frame 15 (ORF15) of RPGR has been implicated to play a substantial role. We identified a novel hemizygous missense mutation E585K of RPGR from whole-exome sequencing of RP. RNA-Seq analysis and functional study were conducted to investigate the underlying pathogenic mechanism of the mutation. Our results showed that the mutation actually affected RPGR ORF15 splicing. RNA-Seq analysis of the human retina followed by validation in cells revealed a complex splicing pattern near the 3' boundary of RPGR exon 14 in the ORF15 region, resulting from a variety of alternative splicing events (ASEs). The wildtype RPGR mini-gene expressed in human 293T cells confirmed these ASEs in vitro. In contrast, without new RNA species detected, the mutant mini-gene disrupted the splicing pattern of the ORF15 region, and caused loss of RPGR transcript heterogeneity. The RNA species derived from the mutant mini-gene were predominated by a minor out-of-frame transcript that was also observed in wildtype RPGR, resulting from an upstream alternative 5' splice site in exon 14. Our findings therefore provide insights into the influence of RPGR exonic mutations on alternative splicing of the ORF15 region, and the underlying molecular mechanism of RP.

Novel NTRK1 mutations in Chinese patients with congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disorder, characterized by loss of algesthesis and inability to sweat. CIPA is known to be caused by mutations in the neurotrophic tyrosine kinase receptor type 1 gene ( NTRK1). However, the details of NTRK1 mutations in Chinese CIPA patients remain unclear. In the present study, we recruited 36 CIPA patients from 34 unrelated families in mainland China. Blood samples from these patients and their available familial members were collected and subjected to genetic analysis. We identified 27 mutations in NTRK1 from this cohort, including 15 novel mutations. Interestingly, we discovered two forms of novel recurrent mutations: the first was a large intragenic deletion c.429-374_717 + 485del mediated by recombination between Alu elements, and the second was a deep intronic substitutions c.[851-798C > T;851-794C > G]. All probands were homozygotes or compound heterozygotes of these mutations. Current findings expand our knowledge about the mutation spectrum of NTRK1 in Chinese CIPA patients and provide more evidence for precise diagnosis of the clinically suspected patients with CIPA.

Correction to: Novel Mutations in RASGRP1 Are Associated with Immunodeficiency, Immune Dysregulation, and EBV-Induced Lymphoma.

The original version of this article unfortunately contained mistakes in Author's name, in Table 1 and in result section.

Novel Mutations in RASGRP1 are Associated with Immunodeficiency, Immune Dysregulation, and EBV-Induced Lymphoma.

PURPOSE: RAS guanyl-releasing protein 1 (RASGRP1) deficiency has recently been shown to cause a primary immunodeficiency (PID) characterized by CD4+ T cell lymphopenia and Epstein-Barr virus (EBV)-associated B cell lymphoma. Our report of three novel patients widens the scope of RASGRP1 deficiency by providing new clinical and immunological insights on autoimmunity, immune cell development, and predisposition to lymphoproliferative disease. METHODS: One patient of Turkish origin (P1) and two Palestinian patients (P2, P3) were evaluated for immunodeficiency. To decipher the molecular cause of disease, whole exome sequencing was conducted. Identified mutations were validated by immunological and biochemical assays. RESULTS: We report three patients presenting with similar clinical characteristics of immunodeficiency and EBV-associated lymphoproliferative disease. In addition, P2 and P3 exhibited overt autoimmune manifestations. Genetic screening identified two novel loss-of-function mutations in RASGRP1. Immunoblotting and active Ras pull-down assays confirmed perturbed ERK1/2 signaling and reduced Ras-GTPase activity in heterologous Jurkat cells with ectopic expression of RASGRP1 mutants. All three patients had CD4+ T cell lymphopenia. P2 and P3 showed decreased mitogen-induced lymphocyte proliferation, reduced T cell receptor excision circles, abnormal T cell receptor (TCR) Vß repertoires, and increased frequencies of TCRγδ cells. TCR gamma repertoire diversity was significantly reduced with a remarkable clonal expansion. CONCLUSIONS: RASGRP1 deficiency is associated with life-threatening immune dysregulation, severe autoimmune manifestations, and susceptibility to EBV-induced B cell malignancies. Early diagnosis is critical and hematopoietic stem cell transplantation might be considered as curative treatment.

[Identification of a novel mutation of DSPP gene in a Chinese family affected with dentinogenesis imperfecta shields type II].

OBJECTIVE: To identify the causative mutation in a Chinese family affected with dentinogenesis imperfecta shields type II (DGI-II). METHODS: With informed consent obtained from all participants, peripheral blood or chorionic villi samples were collected from the family members. Genomic DNA was extracted using a standard SDS-proteinase K-phenol/chloroform method. The whole coding region and exon/intron boundaries of the DSPP gene were amplified with polymerase chain reaction (PCR) and subjected to Sanger sequencing. To confirm the pathogenicity of the identified mutation, an Alu I recognition sequence was introduced into the mutant allele using mismatch primers by semi-nested PCR. Restriction fragment length polymorphism (RFLP) analysis was then carried out for all family members and 60 unrelated healthy controls. Meanwhile, mini-DSPP constructs were conducted to confirm the effect of the mutation in vitro. RESULTS: A splicing site mutation, c.52-1G>A, which was located upstream of exon 3, was found in all three patients and the fetus of the proband. Restriction analysis confirmed that all unaffected individuals and the 60 healthy controls did not carry the same mutation. The expression of minigene showed that the exon 3 of the DSPP gene was skipped during the transcription. CONCLUSION: A novel pathogenic splicing-mutation c.52-1G>A has been detected in a Chinese family affected with DGI-II, which enabled prenatal diagnosis for the fetus of the proband.

Analysis of genetic regulation and cytokine expressions of distraction osteogenesis reconstruction for cleft palate.

Because cleft palate (CP) is one of the most common congenital deformities, surgeons have tried for longtime to achieve an ideal reconstruction of the palatal bone defects and restoration of muscle attachments. In this study, a new CP model on rhesus was established and corrected by an approach of distraction osteogenesis (DO), and then quantitative studies of regulation of osteogenesis genes and expression of alkaline phosphatase (ALP), insulin-like growth factor-I (IGF-I), osteopontin (OPN), and osteocalcin (OC) in different phases of new bone formation were preformed. The CP models (23 animals) were established surgically. In the experimental group (21 animals), the tissue defects were repaired by means of DO at the rhythm of 0.4 mm twice per day. The specimens were retrieved in 1, 2, 4, 6, 8, 12, and 24 weeks (3 animals each) after completion of distraction. The IGF-I, ALP, OPN, and OC messenger RNA (mRNA) were detected by real-time reverse transcription polymerase chain reaction, and their proteins were then analyzed by enzyme-linked immunosorbent assay tests. The results are compared with those of the experimental control and empty control groups (2 animals each). In the distraction gap, the mRNA and protein expressions levels of IGF-I and ALP were both highly upregulated and reaching apex in the early phase of new bone formation. Otherwise, the mRNA and protein expressions of OPN and OC demonstrated high level during intermediate and later remodeling stages. These results suggest that the reconstruction of CP bone defect by means of DO could get definitely intramembraneous new bone formation and eventually quite normal bone structure via consecutive remodeling in situ.

Performance of 3D printed porous polyetheretherketone composite scaffolds combined with nano-hydroxyapatite/carbon fiber in bone tissue engineering: a biological evaluation.

Polyetheretherketone (PEEK) has been one of the most promising materials in bone tissue engineering in recent years, with characteristics such as biosafety, corrosion resistance, and wear resistance. However, the weak bioactivity of PEEK leads to its poor integration with bone tissues, restricting its application in biomedical fields. This research effectively fabricated composite porous scaffolds using a combination of PEEK, nano-hydroxyapatite (nHA), and carbon fiber (CF) by the process of fused deposition molding (FDM). The experimental study aimed to assess the impact of varying concentrations of nHA and CF on the biological performance of scaffolds. The incorporation of 10% CF has been shown to enhance the overall mechanical characteristics of composite PEEK scaffolds, including increased tensile strength and improved mechanical strength. Additionally, the addition of 20% nHA resulted in a significant increase in the surface roughness of the scaffolds. The high hydrophilicity of the PEEK composite scaffolds facilitated the in vitro inoculation of MC3T3-E1 cells. The findings of the study demonstrated that the inclusion of 20% nHA and 10% CF in the scaffolds resulted in improved cell attachment and proliferation compared to other scaffolds. This suggests that the incorporation of 20% nHA and 10% CF positively influenced the properties of the scaffolds, potentially facilitating bone regeneration. In vitro biocompatibility experiments showed that PEEK composite scaffolds have good biosafety. The investigation on osteoblast differentiation revealed that the intensity of calcium nodule staining intensified, along with an increase in the expression of osteoblast transcription factors and alkaline phosphatase activities. These findings suggest that scaffolds containing 20% nHA and 10% CF have favorable properties for bone induction. Hence, the integration of porous PEEK composite scaffolds with nHA and CF presents a promising avenue for the restoration of bone defects using materials in the field of bone tissue engineering.

A female patient carrying a novel DMD mutation with non-random X-chromosome inactivation from a DMD family.

OBJECTIVE: To analyze the clinical phenotype and genetic characteristics of a female proband carrying a novel mutation in the DMD gene with non-random X-chromosome inactivation in a large pedigree with pseudohypertrophic muscular dystrophy. METHODS: Clinical information of the female proband, her monozygotic twin sister, and other family members were collected. Potential pathogenic variants were detected with Multiplex Ligation-dependent Probe Amplification (MLPA) and whole-exome sequencing (WES). Methylation-sensitive restriction enzyme (HhaI) was employed for X-chromosome inactivation analysis. RESULTS: The proband was a female over 5 years old, displayed clinical manifestations such as elevated creatine kinase (CK) levels and mild calf muscle hypertrophy. Her monozygotic twin sister exhibited normal CK levels and motor ability. Her uncle and cousin had a history of DMD. WES revealed that the proband carried a novel variant in the DMD (OMIM: 300,377) gene: NM_004006.3: c.3051_3053dup; NP_003997.2: p.Tyr1018*. In this pedigree, five out of six female members were carriers of this variant, while the cousin and uncle were hemizygous for this variant. X-chromosome inactivation analysis suggested non-random inactivation in the proband. CONCLUSION: The c.3051_3053dup (p.Tyr1018*) variant in the DMD gene is considered to be the pathogenic variant significantly associated with the clinical phenotype of the proband, her cousin, and her uncle within this family. Integrating genetic testing with clinical phenotype assessment can be a valuable tool for physicians in the diagnosis of progressive muscular dystrophies, such as Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD).

Engineered CBEs based on Macaca fascicularis A3A with improved properties for precise genome editing.

Cytidine deaminase defines the properties of cytosine base editors (CBEs) for C-to-T conversion. Replacing the cytidine deaminase rat APOBEC1 (rA1) in CBEs with a human APOBEC3A (hA3A) improves CBE properties. However, the potential CBE application of macaque A3A orthologs remains undetermined. Our current study develops and evaluates engineered CBEs based on Macaca fascicularis A3A (mA3A). Here, we demonstrate that BE4-mA3A and its RNA-editing-derived variants exhibit improved CBE properties, except for DNA off-target activity, compared to BE3-rA1 and BE4-rA1. Unexpectedly, deleting Ser-Val-Arg (SVR) in BE4-mA3A dramatically reduces DNA and RNA off-target activities and improves editing accuracy, with on-target efficiency unaffected. In contrast, a chimeric BE4-hA3A-SVR+ shows editing efficiency increased by about 50%, with other properties unaffected. Our findings demonstrate that mA3A-based CBEs could provide prototype options with advantages over rA1- and hA3A-based CBEs for further optimization, highlighting the importance of the SVR motif in defining CBE intrinsic properties.

A Chromosomal-Level Genome of Dermatophagoides farinae, a Common Allergenic Mite Species.

Background: Genome data have been used to find novel allergen from house dust mites. Here, we aim to construct a chromosome-level genome assembly of Dermatophagoides farinae, a common allergenic mite species. Methods: We achieved a chromosome-level assembly of D. farinae's genome by integrating PacBio single-molecule real-time sequencing, Illumina paired-end sequencing, and Hi-C technology, followed by annotating allergens and mapping them to specific chromosomes. Results: A 62.43 Mb genome was assembled with a 0.52% heterozygosity rate and a 36.11 Merqury-estimated quality value. The assembled genome represents 92.1% completeness benchmarking universal single-copy orthologs with a scaffold N50 value of 7.11 Mb. Hi-C scaffolding of the genome resulted in construction of 10 pseudochromosomes. The genome comprises 13.01% (7.66 Mb) repetitive sequences and predicts 10,709 protein-coding genes, 96.57% of which are functionally annotated. Moreover, we identified and located 36 allergen groups on specific chromosomes, including allergens Der f 1, Der f 2, Der f 23, Der f 4, Der f 5, Der f 7, and Der f 21 located on chromosomes 2, 1, 7, 3, 4, 6, and 4, respectively. Conclusion: This comprehensive genomic data provides valuable insights into mite biology and evolutionary adaptations, potentially advancing D. farinae allergy research and treatment strategies.

Application of 3D printed titanium mesh and digital guide plate in the repair of mandibular defects using double-layer folded fibula combined with simultaneous implantation.

Fibula transplantation plays an irreplaceable role in restoring the function and morphology of the defected mandible. However, the complex load-bearing environment of the mandible makes it urgent to accurately reconstruct the mandible, ensure the position of the condyle after surgery, and restore the patient's occlusal function and contour. The intervention of digital design and three-dimensional (3D) printed titanium mesh provides a more efficient method and idea to solve this problem. Digital design guides the accurate positioning, osteotomy, and simultaneous implant placement during surgery, and 3D printed titanium mesh ensures stable condyle position after surgery, restoring good mandibular function. The double-layer folded fibula maintains the vertical height of the mandible and a good facial contour, and simultaneous implant placement can establish a good occlusal relationship. This study conducted a retrospective analysis of five patients with jaw defects who underwent digital fibula reconstruction over the past 3 years. It was found that the surgical protocol combining digital design, 3D printed intraoperative guides, 3D printed titanium mesh, free fibula flap, immediate implant, and occlusal reconstruction to repair jaw defects had more ideal facial appearance and biological function. It will provide a more reliable surgical protocol for clinical management of large mandibular defects.

Preparation and properties of a 3D printed nHA/PLA bone tissue engineering scaffold loaded with a ß-CD-CHX combined dECM hydrogel.

Jaw defects, which can result from a multitude of causes, significantly affect the physical well-being and psychological health of patients. The repair of these infected defects presents a formidable challenge in the clinical and research fields, owing to their intricate and diverse nature. This study aims to develop a personalized bone tissue engineering scaffold that synergistically offers antibacterial and osteogenic properties for treating infected maxillary defects. This study engineered a novel temperature-sensitive, sustained-release hydrogel by amalgamating ß-cyclodextrin (ß-CD) with chlorhexidine (CHX) and a decellularized extracellular matrix (dECM). This hydrogel was further integrated with a polylactic acid (PLA)-nano hydroxyapatite (nHA) scaffold, fabricated through 3D printing, to form a multifaceted composite scaffold (nHA/PLA/dECM/ß-CD-CHX). Drug release assays revealed that this composite scaffold ensures prolonged and sustained release. Bacteriological studies confirmed that the ß-CD-CHX loaded scaffold exhibits persistent antibacterial efficacy, thus effectively inhibiting bacterial growth. Moreover, the scaffold demonstrated robust mechanical strength. Cellular assays validated its superior biocompatibility, attributed to dECM and nHA components, significantly enhancing the proliferation, adhesion, and osteogenic differentiation of osteogenic precursor cells (MC3T3-E1). Consequently, the nHA/PLA/dECM/ß-CD-CHX composite scaffold, synthesized via 3D printing technology, shows promise in inducing bone regeneration, preventing infection, and facilitating the repair of jaw defects, positioning itself as a potential breakthrough in bone tissue engineering.