Integrating scRNA-seq and bulk RNA-seq to explore the differentiation mechanism of human nail stem cells mediated by onychofibroblasts.

Introduction: Nail stem cell (NSC) differentiation plays a vital role in maintaining nail homeostasis and facilitating digit regeneration. Recently, onychofibroblasts (OFs), specialized mesenchymal cells beneath the nail matrix, have emerged as potential regulators of NSC differentiation. However, limited understanding of OFs' cellular properties and transcriptomic profiles hinders our comprehension of their role. This study aims to characterize human OFs and investigate their involvement in NSC differentiation. Methods: Human OFs were isolated and characterized for their mesenchymal stem cell (MSC)-like phenotype through flow cytometry and multilineage differentiation assays. Bulk RNA-seq analysis was conducted on three samples of OFs and control fibroblasts from human nail units to delineate their molecular features. Integrated analysis with scRNA-seq data was performed to identify key signaling pathways involved in OF-induced NSC differentiation. Co-culture experiments, siRNA transfection, RT-qPCR, and immunocytochemistry were employed to investigate the effect of OF-derived soluble proteins on NSC differentiation. Drug treatments, RT-qPCR, western blotting, and immunocytochemistry were used to verify the regulation of candidate signaling pathways on NSC differentiation in vitro. Results: Human OFs exhibited slow cell cycle kinetics, expressed typical MSC markers, and demonstrated multilineage differentiation potential. Bulk RNA-seq analysis revealed differential gene expression in OFs compared to control fibroblasts, highlighting their role in coordinating nail development. Integrated analysis identified BMP4 as a pivotal signal for OFs to participate in NSC differentiation through mesenchymal-epithelial interactions, with the TGF-beta pathway possibly mediating this signal. OFs synthesized and secreted more BMP4 than control fibroblasts, and BMP4 derived from OFs induced NSC differentiation in a co-culture model. Recombinant human BMP4 activated the TGF-beta pathway in NSCs, leading to cell differentiation, while the BMP type I receptor inhibitor LDN193189 attenuated this effect. Discussion: This study characterizes the cellular and molecular features of human OFs, demonstrating their ability to regulate NSC differentiation via the TGF-beta signaling pathway. These findings establish a connection between the dermal microenvironment and NSC differentiation, suggesting the potential of OFs, in conjunction with NSCs, for developing novel therapies targeting nail and digit defects, even severe limb amputation.

A retrospective study on the correction of distal arthrogryposis with a progressive extension brace.

Purpose: Camptodactyly, clasped thumbs, and windblown hands are distinctive features of distal arthrogryposis (DA). Current therapeutic interventions often yield suboptimal effects, predisposing patients to relapses and complications. This study explicates a corrective approach involving a progressive extension brace for the management of DA and evaluates its clinical outcomes. Methods: Between 2015 and 2023, progressive extension braces were used in 32 DA patients, with an average follow-up of 4.8 years. Patients were stratified by age into four groups: 0-1, 1-3, 3-7, and above 7 years. The correction of camptodactyly was assessed based on the total active movement (TAM) of metacarpophalangeal joints (MPJ) and proximal interphalangeal joints (PIPJ), as well as the extensor lag of PIPJ. Clasped thumb correction was evaluated by measuring the thumb-to-index finger metacarpal angle (M1M2 angle) and the degree of deviation at the first MPJ (M1P1 angle). The quality of life for the children was measured using PedsQL 4.0, while parental satisfaction was gauged using the FACE questionnaire. Results: Earlier intervention with a progressive extension brace yielded superior corrective results. Infants aged 0-1 year and toddlers aged 1-3 years achieved average TAM scores of 152° and 126° after correction; however, patients older than 3 years experienced a significant decrease in TAM with the same treatment. Infants and toddlers with DA showed improvement in the average extensor lag from 46° to 6°. The M1M2 angle increased from an average of 38° to 65°, with the M1P1 angle decreasing from an average of 43° to 5°. After the treatment, average PedsQL scores of 94.7 (parent-reported) and 89.3 (child-reported) were achieved. Among the 32 parents, 24 expressed high satisfaction, 5 expressed moderate satisfaction, and 3 expressed fair satisfaction. Conclusion: The early, progressive, and consistent use of an extension brace significantly improved joint mobility and corrected camptodactyly and clasped thumbs. It can be an effective approach to addressing hand deformities in patients with DA.

Antimicrobial and Antiviral Nanofibers Halt Co-Infection Spread via Nuclease-Mimicry and Photocatalysis.

The escalating spread of drug-resistant bacteria and viruses is a grave concern for global health. Nucleic acids dominate the drug-resistance and transmission of pathogenic microbes. Here, imidazolium-type poly(ionic liquid)/porphyrin (PIL-P) based electrospun nanofibrous membrane and its cerium (IV) ion complex (PIL-P-Ce) are developed. The obtained PIL-P-Ce membrane exhibits high and stable efficiency in eradicating various microorganisms (bacteria, fungi, and viruses) and decomposing microbial antibiotic resistance genes and viral nucleic acids under light. The nuclease-mimetic and photocatalytic mechanisms of the PIL-P-Ce are elucidated. Co-infection wound models in mice with methicillin-resistant S. aureus and hepatitis B virus demonstrate that PIL-P-Ce integrate the triple effects of cationic polymer, photocatalysis, and nuclease-mimetic activities. As revealed by proteomic analysis, PIL-P-Ce shows minimal phototoxicity to normal tissues. Hence, PIL-P-Ce has potential as a "green" wound dressing to curb the spread of drug-resistant bacteria and viruses in clinical settings.

Reconstruction of Type IIIB Thumb Hypoplasia Using a Vascularized Hemi-Metatarsal Composite Tissue Flap.

BACKGROUND: The aim of this study was to determine the clinical outcomes of vascularized hemi-metatarsal composite tissue transfer for the reconstruction of type IIIB hypoplastic thumbs. METHODS: Twenty-eight patients with type IIIB hypoplastic thumbs treated with vascularized hemi-metatarsal composite tissue transfer were included in this retrospective study with a mean follow-up of 2.4 years. Preoperative digital subtraction angiography was performed to examine the vessel variance. Clinical measures included grip and pinch strength, scar status, and Kapandji thumb opposition score. Subjective Pediatric Outcomes Data Collection Instrument scores and parent satisfaction were also evaluated. RESULTS: Radial arteries were hypoplastic in 82.1% of the cases, and the common palmar digital artery was chosen as the recipient vessel for the tissue transfer. There was no neurovascular complication. The only donor-site complication was a metatarsal fracture that healed with casting. Key pinch and tripod pinch were 29.5% and 45.8% of the normal side, respectively. The mean grip strength was 51.7% of the unaffected side. The mean Kapandji score was 6. The Pediatric Outcomes Data Collection Instrument scores were high for global function; upper extremity function; transfer; and basic mobility, happiness, and comfort. The Vancouver Scar Scale showed an average score of 2.1. All parents were satisfied with the clinical outcomes. CONCLUSION: Vascularized hemi-metatarsal composite tissue transfer for type IIIB thumb hypoplasia can provide improved subjective outcomes and is a feasible method for the attainment of a five-digit hand. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

The inhibitory role of microRNA-141-3p in human cutaneous melanoma growth and metastasis through the fibroblast growth factor 13-mediated mitogen-activated protein kinase axis.

Human cutaneous melanoma (CM) is a highly invasive malignancy arising from melanocytes, and accompanied by ever-increasing incidence and mortality rates worldwide. Interestingly, microRNAs (miRNAs) possess the ability to regulate CM cell biological functions, resulting in the aggressive progression of CM. Nevertheless, a comprehensive understanding of the underlying mechanism remains elusive. Accordingly, the current study sought to elicit the functional role of miR-141-3p in human CM cells in association with fibroblast growth factor 13 (FGF13) and the MAPK pathway. First, miR-141-3p expression patterns were detected in human CM tissues and cell lines, in addition to the validation of the targeting relationship between miR-141-3p and FGF13. Subsequently, loss- and gain-of-function studies of miR-141-3p were performed to elucidate the functional role of miR-141-3p in the malignant features of CM cells. Intriguingly, our findings revealed that FGF13 was highly expressed, whereas miR-141-3p was poorly expressed in the CM tissues and cells. Further analysis highlighted FGF13 as a target gene of miR-141-3p. Meanwhile, overexpression of miR-141-3p inhibited the proliferative, invasive, and migratory abilities of CM cells, while enhancing their apoptosis accompanied by downregulation of FGF13 and the MAPK pathway-related genes. Collectively, our findings highlighted the inhibitory effects of miR-141-3p on CM cell malignant properties via disruption of the FGF13-dependent MAPK pathway, suggesting a potential target for treating human CM.

A Novel Missense Variant of HOXD13 Caused Atypical Synpolydactyly by Impairing the Downstream Gene Expression and Literature Review for Genotype-Phenotype Correlations.

Synpolydactyly (SPD) is a hereditary congenital limb malformation with distinct syndactyly designated as SPD1, SPD2, and SPD3. SPD1 is caused by mutations of HOXD13, which is a homeobox transcription factor crucial for limb development. More than 143 SPD patients have been reported to carry HOXD13 mutations, but there is a lack of genotype-phenotype correlation. We report a novel missense mutation of c. 925A > T (p.I309F) in an individual with atypical synpolydactyly inherited from her father with mild clinodactyly and three other different alanine insertion mutations in HOXD13 identified by whole exome sequencing (WES) in 12 Chinese SPD families. Unlike polyalanine extension, which tends to form α-helix and causes protein aggregation in the cytoplasm as shown by molecular simulation and immunofluorescence, the c. 925A > T mutation impairs downstream transcription of EPHA7. We compiled literature findings and analyzed genotype-phenotype features in 173 SPD individuals of 53 families, including 12 newly identified families. Among the HOXD13-related individuals, mutations were distributed in three regions: polyalanine, homeobox, and non-homeobox. Polyalanine extension was the most common variant (45%), followed by missense mutations (32%) mostly in the homeobox compared with the loss-of-function (LOF) variants more likely in non-homeobox. Furthermore, a more severe degree and classic SPD were associated with polyalanine mutations although missense variants were associated with brachydactyly and syndactyly in hands and feet and LOF variants with clinodactyly in hands. Our study broadens the HOXD13 mutation spectrum and reveals the profile of three different variants and their severity of SPD, the genotype-phenotype correlation related to the HOXD13 mutation site provides clinical insight, including for genetic counseling.