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BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has poor prognosis due to its low surgical eligibility and resistance to chemotherapy. Abundant stroma is characteristic of PDAC, and cancer-associated fibroblasts (CAFs) are a major stromal constituent, contributing to chemoresistance. Because neoadjuvant chemotherapy (NAC) is included in PDAC treatment as a standard regimen, the role of CAFs in NAC resistance must be studied. Although type IV collagen (COLIV) is present in the tumor of PDAC, the association between COLIV and disease advancement of NAC-treated PDAC is unclear. METHODS: Using a cohort of NAC-treated patients with PDAC, we examined clinicopathological data and conducted immunohistochemical analysis of COLIV in tissue specimens prepared from surgically resected pancreas. RESULTS AND CONCLUSIONS: Our analysis revealed that ~50% of the cases were positive for COLIV in the stroma and diffuse COLIV staining was an independent poor prognosis factor alongside high serum CA19-9 before NAC treatment (>37 U/mL) and postsurgical residual tumors. Based on these findings, we propose that stromal COLIV staining can be used to predict prognosis in NAC-treated patients with PDAC after surgery. Additionally, these findings suggest a possibility that stromal COLIV staining indicates resistance to anticancer drugs and/or contributes to malignancy in PDAC.
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COVID-19 patients often suffer from post-COVID-19 acute sequelae (PASC). Pulmonary fibrosis has the most significant long-term impact on the respiratory health of patients, known as post-COVID-19 pulmonary fibrosis (PC19-PF). PC19-PF can be caused by acute respiratory distress syndrome (ARDS) or COVID-19-induced pneumonia. Individuals who experience COVID-19 pneumonia symptoms (including cough, shortness of breath, dyspnea on exertion, and desaturation) for at least 12 weeks after diagnosis, almost all develop PC19-PF. Extracellular matrix molecules: laminin (LN), type IV collagen (IV Col), procollagen III N-terminal peptide (PIIINP), and hyaluronic acid (HA) are involved in the development and progression of PC19-PF. This study aimed to investigate the relationship between the progression of PC19-PF and serum levels of laminin, IV COL, PIIINP, and hyaluronic acid. This retrospective study included 162 PC19-PF patients treated and 160 healthy controls who received treatment at Shenzhen Longgang District Third People's Hospital, Hebei PetroChina Central Hospital and Changzhi People's Hospital from January 2021 to December 2023. Serum levels of LN, IV COL, PIIINP, and HA were detected by chemiluminescence immunoassay using commercial kits. Predicted forced vital capacity percentage (FVC% pred), predicted carbon monoxide lung diffusion capacity percentage (DLCO% pred), high-resolution computed tomography (HRCT) scores were assessed, and patient mortality was compared with healthy controls. Serum levels of LN, IV Col, PIIINP, and HA were significantly higher in PC19-PF or CTD-ILD patients than in healthy controls (all p < 0.05), and they were further elevated in acute exacerbation cases (all p < 0.01). In patients, HA was positively associated with HRCT scores and negatively associated with FVC% pred and DLCO% pred (all p < 0.05). Serum levels of LN, IV COL, PIIINP, and HA were significantly lower in surviving patients than in those who deceased (all p > 0.05). Serum levels of LN, IV C, PIIINP, and HA may affect the progression of PC19-PF and may serve as indicators of PC19-PF severity.
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Alport syndrome (AS) is characterized by progressive kidney failure, hematuria, sensorineural hearing loss, and ocular abnormalities. Pathogenic variants in the COL4A3-5 genes result in a defective deposition of the collagen IV α3α4α5 protomers in the basement membranes of the glomerulus in the kidney, the cochlea in the ear and the cornea, lens capsule and retina in the eye. The presence of a large variety of COL4A3-5 gene(s) pathogenetic variants irrespective of the mode of inheritance (X-linked, autosomal recessive, autosomal dominant, or digenic) with and without syndromic features is better defined as the "Alport spectrum disorder", and represents the most common cause of genetic kidney disease and the second most common cause of genetic kidney failure. The clinical course and prognosis of individuals with AS is highly variable. It is influenced by gender, mode of inheritance, affected gene(s), type of genetic mutation, and genetic modifiers. This review article will discuss the epidemiology, classification, pathogenesis, diagnosis, clinical course with genotype-phenotype correlations, and current and upcoming treatment of patients with AS. It will also review current recommendations with respect to when to evaluate for hearing loss or ophthalmologic abnormalities.
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Néphropathie familiale avec surdité , Néphropathie familiale avec surdité/génétique , Néphropathie familiale avec surdité/diagnostic , Néphropathie familiale avec surdité/thérapie , Humains , Collagène de type IV/génétiqueRÉSUMÉ
BACKGROUND: Alport syndrome is a genetic disorder caused by mutations in the COL4A5 gene, which encodes type IV collagen α5 chain, leading to chronic nephritis, hearing loss, and ocular abnormalities. Recent reports suggest this genetic mutation may also increase the risk of cerebral aneurysms and fibromuscular dysplasia, indicating a potential association with vascular vulnerability. CASE PRESENTATION: A 66-year-old woman was admitted with recurrent transient weakness of the left hand, which had gradually worsened in duration over three months. Her medical history included chronic nephritis since childhood. Her two sons had end-stage renal disease and hearing loss since their 20s, and her mother also had chronic kidney disease and hearing loss. One son had a history of traumatic subarachnoid hemorrhage, and the other had spinal epidural hematoma. On admission, she had reduced renal function with proteinuria, acute cerebral infarction in the subcortical white matter of the right fronto-parietal and parieto-occipital lobes, and multiple intracranial arterial stenoses (ICAS), including the right middle and right posterior cerebral artery. Vessel wall imaging of the right middle cerebral artery showed a concentric stenotic pattern. Genetic tests identified a pathogenic missense mutation in exon 24 of COL4A5 (exon 24:c.G1700 >C: p.(Gly567Arg)) that was heterozygous for the patient and hemizygous for her son. She was diagnosed with Alport syndrome. CONCLUSION: It is important to consider Alport syndrome as a possible cause of ICAS in patients with a family history of renal failure or hearing loss and to conduct a genetic analysis of type IV collagen genes. (249/250 words).
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The periocular mesenchyme (POM) is a transient migratory embryonic tissue derived from neural crest cells (NCCs) and paraxial mesoderm that gives rise to most of the structures in front of the eye. Morphogenetic defects of these structures can impair aqueous humor outflow, leading to elevated intraocular pressure and glaucoma. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome - a multisystem disorder often characterized by variable cerebrovascular, ocular, renal, and neuromuscular manifestations. Approximately one-third of individuals with COL4A1 and COL4A2 mutations have ocular anterior segment dysgenesis (ASD), including congenital glaucoma resulting from abnormalities of POM-derived structures. POM differentiation has been a major focus of ASD research, but the underlying cellular mechanisms are still unclear. Moreover, earlier events including NCC migration and survival defects have been implicated in ASD; however, their roles are not as well understood. Vascular defects are among the most common consequences of COL4A1 and COL4A2 mutations and can influence NCC survival and migration. We therefore hypothesized that NCC migration might be impaired by COL4A1 and COL4A2 mutations. In this study, we used 3D confocal microscopy, gross morphology, and quantitative analyses to test NCC migration in Col4a1 mutant mice. We show that homozygous Col4a1 mutant embryos have severe embryonic growth retardation and lethality, and we identified a potential maternal effect on embryo development. Cerebrovascular defects in heterozygous Col4a1 mutant embryos were present as early as E9.0, showing abnormal cerebral vasculature plexus remodeling compared to controls. We detected abnormal NCC migration within the diencephalic stream and the POM in heterozygous Col4a1 mutants whereby mutant NCCs formed smaller diencephalic migratory streams and POMs. In these settings, migratory NCCs within the diencephalic stream and POM localize farther away from the developing vasculature. Our results show for the first time that Col4a1 mutations lead to cranial NCCs migratory defects in the context of early onset defective angiogenesis without affecting cell numbers, possibly impacting the relation between NCCs and the blood vessels during ASD development.
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Mouvement cellulaire , Collagène de type IV , Modèles animaux de maladie humaine , Malformations oculaires , Mutation , Crête neurale , Crête neurale/métabolisme , Crête neurale/anatomopathologie , Animaux , Collagène de type IV/génétique , Collagène de type IV/métabolisme , Mouvement cellulaire/génétique , Souris , Malformations oculaires/génétique , Malformations oculaires/anatomopathologie , Mutation/génétique , Pôle antérieur du bulbe oculaire/malformations , Pôle antérieur du bulbe oculaire/anatomopathologieRÉSUMÉ
Background: Previous studies have attempted to establish predictive models for post-hepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma (HCC) undergoing liver resection. However, a versatile and useful predictive model for PHLF remains to be developed. Therefore, we aimed to develop predictive models for PHLF based on type IV collagen 7s domain (7s collagen) in patients with HCC. Methods: We retrospectively collected data from 972 patients with HCC who had undergone initial curative liver resection between February 2000 and December 2020 at our hospital. Multivariate logistic regression analysis using a restricted cubic spline was performed to evaluate the effect of 7s collagen on the incidence of PHLF. A nomogram was developed based on 7s collagen. Results: PHLF grades B or C were identified in 104 patients (11%): 98 (10%) and 6 (1%) PHLF grades B and C, respectively. Multivariate logistic regression analysis revealed that the preoperative serum level of 7s collagen was significantly associated with a proportional increase in the risk of PHLF, which was confirmed in both laparoscopic and open liver resections. A nomogram was developed based on 7s collagen, with a concordance index of 0.768. The inclusion of 7s collagen values in the predictive model increased the predictive accuracy. Conclusion: The findings highlight the efficacy of the serum level of 7s collagen as a predictive factor for PHLF. Our novel nomogram using 7s collagen may be useful for predicting the risk of PHLF.
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Type IV collagen, a principal constituent of basement membranes, consists of six distinct α chains that assemble into both ABC and AAB-type heterotrimers. While collagen-like peptides have been investigated for heterotrimer formation, the construction of ABC-type heterotrimeric collagen mimetic peptides remains a formidable challenge, primarily due to the intricate composition and arrangement of the chains. We have herein for the first time reported the development of a versatile triblock peptide system to mimic ABC-type heterotrimeric collagen stabilized by salt bridges. The triblock peptides A, B, and C incorporate functional natural type IV collagen sequences in the center, along with charged amino acids at their N and C-terminals. By leveraging electrostatic repulsion at these charged termini, the formation of homotrimers is effectively inhibited, while stable ABC-type heterotrimers are generated through the establishment of salt bridges between oppositely charged terminals. Circular dichroism (CD) spectroscopy demonstrated that peptides A, B, and C existed as individual monomers, while they effectively formed stable ABC-type heterotrimers upon being mixed at a molar ratio of 1:1:1. Additionally, fluorescence quenching results indicated that fluorescence-labeled peptides A', B', and C' formed ABC-type heterotrimer, exhibiting comparable thermal stability as determined by CD spectroscopy. Molecular dynamics simulations elucidated the role of salt bridges between arginine and aspartic acid residues at N- and C-terminals in maintaining a unique chain register in the ABC-type heterotrimers. These triblock peptides offer a robust approach for replicating the structural and functional characteristics of type IV collagen, with promising applications in elucidating the biological roles and pathologies associated with heterotrimeric collagen.
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Peptides , Peptides/composition chimique , Multimérisation de protéines , Collagène de type IV/composition chimique , Sels/composition chimique , Séquence d'acides aminés , Stabilité protéique , Collagène/composition chimique , Dichroïsme circulaire , Simulation de dynamique moléculaireRÉSUMÉ
BACKGROUND: Alport syndrome (AS) is a common and heterogeneous genetic kidney disease, that often leads to end-stage kidney disease (ESKD). METHODS: This is a single-center, retrospective study that included 36 adults with type IV collagen (COL4) mutations. Our main scope was to describe how genetic features influence renal survival. RESULTS: A total of 24 different mutations were identified, of which eight had not been previously described. Mutations affecting each of the type IV collagen α chains were equally prevalent (33.3%). Most of the patients had pathogenic variants (61.1%). Most patients had a family history of kidney disease (71%). The most prevalent clinical picture was nephritic syndrome (64%). One-third of the subjects had extrarenal manifestations, 41.6% of patients had ESKD at referral, and another 8.3% developed ESKD during follow-up. The median renal survival was 42 years (95% CI, 29.98-54.01). The COL4A4 group displayed better renal survival than the COL4A3 group (p = 0.027). Patients with missense variants had higher renal survival (p = 0.023). Hearing loss was associated with lower renal survival (p < 0.001). CONCLUSIONS: Patients with COL4A4 variants and those with missense mutations had significantly better renal survival, whereas those with COL4A3 variants and those with hearing loss had worse prognoses.
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Collagène de type IV , Études d'associations génétiques , Défaillance rénale chronique , Néphropathie familiale avec surdité , Humains , Néphropathie familiale avec surdité/génétique , Néphropathie familiale avec surdité/anatomopathologie , Femelle , Mâle , Collagène de type IV/génétique , Adulte , Adulte d'âge moyen , Défaillance rénale chronique/génétique , Défaillance rénale chronique/anatomopathologie , Mutation , Études rétrospectives , AutoantigènesRÉSUMÉ
BACKGROUND: Alport syndrome (AS) is a genetic kidney disease caused by a mutation in type IV collagen α3, α4, and α5, which are normally secreted as heterotrimer α345(IV). Nonsense mutation in these genes causes severe AS phenotype. We previously revealed that the exon-skipping approach to remove a nonsense mutation in α5(IV) ameliorated the AS pathology. However, the effect of removing an exon on trimerization is unknown. Here, we assessed the impact of exon deletion on trimerization to evaluate their possible therapeutic applicability and to predict the severity of mutations associated with exon-skipping. METHODS: We produced exon deletion constructs (ΔExon), nonsense, and missense mutants by mutagenesis and evaluated their trimer formation and secretion activities using a nanoluciferase-based assay that we previously developed. RESULTS: Exon-skipping had differential effects on the trimer secretion of α345(IV). Some ΔExons could form and secrete α345(IV) trimers and had higher activity compared with nonsense mutants. Other ΔExons had low secretion activity, especially for those with exon deletion near the C-terminal end although the intracellular trimerization was normal. No difference was noted in the secretion of missense mutants and their ΔExon counterpart. CONCLUSION: Exon skipping is advantageous for nonsense mutants in AS with severe phenotypes and early onset of renal failure but applications may be limited to ΔExons capable of normal trimerization and secretion. This study provides information on α5(IV) exon-skipping for possible therapeutic application and the prediction of the trimer behavior associated with exon-skipping in Alport syndrome.
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Codon non-sens , Collagène de type IV , Exons , Néphropathie familiale avec surdité , Multimérisation de protéines , Néphropathie familiale avec surdité/génétique , Collagène de type IV/génétique , Collagène de type IV/métabolisme , Humains , Délétion de séquence , Mutation faux-sens , Cellules HEK293 , PhénotypeRÉSUMÉ
We report the case of a 48-year-old man who presented with fatigue and weight loss. A local physician observed elevated alkaline phosphatase levels, anemia, thrombocytopenia, and renal dysfunction. Fever also appeared, and the patient was admitted to our hospital. Computed tomography revealed hepatosplenomegaly, pleural and ascitic fluid, and left axillary lymphadenopathy. Bone marrow biopsy indicated hyperplasia with increased megakaryocytes and reticulin fibrosis. Axillary lymph node biopsy showed Castleman's disease-like features. Liver biopsy revealed proliferation of reticulin fibrosis. Therefore, TAFRO syndrome was diagnosed and treatment with 1 mg/kg prednisolone was started. Anemia and thrombocytopenia improved, and after 24 weeks of treatment, serum hyaluronic acid and type IV collagen decreased to the normal range. Bone marrow biopsy after 18 weeks of treatment showed decreased reticular fibers. In TAFRO syndrome, improvement of liver and bone marrow fibrosis can be expected with adequate intervention, and serum hyaluronic acid and type IV collagen are useful for evaluating fibrosis.
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Prednisolone , Humains , Mâle , Adulte d'âge moyen , Prednisolone/administration et posologie , Hyperplasie lymphoïde angiofolliculaire/traitement médicamenteux , Hyperplasie lymphoïde angiofolliculaire/anatomopathologie , Fibrose , Résultat thérapeutique , SyndromeRÉSUMÉ
Type IV collagen is a major component of the extracellular matrix in adipose tissue. It is secreted during the lipogenic differentiation of mesenchymal stem cells, but its direct impact and mechanism on the differentiation of adipose-derived stem cells (ASCs) into lipids are unclear. In this study, ASCs were obtained from human liposuction samples and cultured. Lipogenic induction of ASCs was achieved using lipogenic induction medium. Immunofluorescence analysis revealed differential expression of type IV collagen during the early and late stages of adipogenic induction, displaying a distinct morphological encapsulation of ASCs. Silencing of type IV collagen using siRNA resulted in a significant decrease in adipogenic capacity, as indicated by reduced lipid droplet formation and downregulation of adipogenic-related gene transcription. Conversely, supplementation of the culture medium with synthetic type IV collagen demonstrated enhanced adipogenic induction efficiency, accompanied by upregulation of YAP/TAZ protein expression and its downstream target gene transcription. Furthermore, inhibition of the YAP/TAZ pathway using the inhibitor Blebbistatin attenuated the functionality of type IV collagen, leading to decreased lipid droplet formation and downregulation of adipocyte maturation-related gene expression. These findings highlight the crucial role of type IV collagen in promoting adipogenic differentiation of ASCs and suggest its involvement in the YAP/TAZ-mediated Hippo pathway.No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
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Adipogenèse , Différenciation cellulaire , Collagène de type IV , Humains , Adipogenèse/physiologie , Adipogenèse/génétique , Collagène de type IV/génétique , Collagène de type IV/métabolisme , Cellules cultivées , Tissu adipeux/cytologie , Adipocytes , Femelle , Cellules souches , AdulteRÉSUMÉ
BACKGROUND: Clinical variability among individuals with heterozygous pathogenic/likely pathogenic (P/LP) variants in the COL4A3/COL4A4 genes (also called autosomal dominant Alport syndrome or COL4A3/COL4A4-related disorder) is huge; many individuals are asymptomatic or show microhematuria, while others may develop proteinuria and chronic kidney disease (CKD). The prevalence of simple kidney cysts (KC) in the general population varies according to age, and patients with advanced CKD are prone to have them. A possible association between heterozygous COL4A3, COL4A4 and COL4A5 P/LP variants and KC has been described in small cohorts. The presence of KC in a multicenter cohort of individuals with heterozygous P/LP variants in the COL4A3/COL4A4 genes is assessed in this study. METHODS: We evaluated the presence of KC by ultrasound in 157 individuals with P/LP variants in COL4A3 (40.7%) or COL4A4 (53.5%) without kidney replacement therapy. The association between presence of KC and age, proteinuria, estimated glomerular filtration rate (eGFR) and causative gene was analyzed. Prevalence of KC was compared with historical case series in the general population. RESULTS: Half of the individuals with P/LP variants in COL4A3/COL4A4 showed KC, which is a significantly higher percentage than in the general population. Only 3.8% (6/157) had cystic nephromegaly. Age and eGFR showed an association with the presence of KC (P < .001). No association was found between KC and proteinuria, sex or causative gene. CONCLUSIONS: Individuals with COL4A3/COL4A4 P/LP variants are prone to develop KC more frequently than the general population, and their presence is related to age and to eGFR. Neither proteinuria, sex nor the causative gene influences the presence of KC in these individuals.
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Autoantigènes , Collagène de type IV , Hétérozygote , Maladies kystiques rénales , Humains , Collagène de type IV/génétique , Femelle , Mâle , Prévalence , Adulte , Adulte d'âge moyen , Maladies kystiques rénales/génétique , Maladies kystiques rénales/épidémiologie , Autoantigènes/génétique , Néphropathie familiale avec surdité/génétique , Néphropathie familiale avec surdité/épidémiologie , Débit de filtration glomérulaire , Jeune adulte , Sujet âgé , Mutation , Kystes/génétique , Kystes/épidémiologie , Pronostic , AdolescentRÉSUMÉ
Focal segmental glomerulosclerosis (FSGS) lesions have been linked to variants in COL4A3/A4/A5 genes, which are also mutated in Alport syndrome. Although it could be useful for diagnosis, quantitative evaluation of glomerular basement membrane (GBM) type IV collagen (colIV) networks is not widely used to assess these patients. To do so, we developed immunofluorescence imaging for collagen α5(IV) and α1/2(IV) on kidney paraffin sections with Airyscan confocal microscopy that clearly distinguishes GBM collagen α3α4α5(IV) and α1α1α2(IV) as two distinct layers, allowing quantitative assessment of both colIV networks. The ratios of collagen α5(IV):α1/2(IV) mean fluorescence intensities (α5:α1/2 intensity ratios) and thicknesses (α5:α1/2 thickness ratios) were calculated to represent the levels of collagen α3α4α5(IV) relative to α1α1α2(IV). The α5:α1/2 intensity and thickness ratios were comparable across all 11 control samples, while both ratios were significantly and markedly decreased in all patients with pathogenic or likely pathogenic Alport COL4A variants, supporting validity of this approach. Thus, with further validation of this technique, quantitative measurement of GBM colIV subtype abundance by immunofluorescence, may potentially serve to identify the subgroup of patients with FSGS lesions likely to harbor pathogenic COL4A variants who could benefit from genetic testing.
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Glomérulonéphrite segmentaire et focale , Néphropathie familiale avec surdité , Humains , Membrane basale glomérulaire/anatomopathologie , Collagène de type IV/génétique , Glomérulonéphrite segmentaire et focale/génétique , Glomérulonéphrite segmentaire et focale/anatomopathologie , Paraffine , Néphropathie familiale avec surdité/diagnostic , Néphropathie familiale avec surdité/génétique , Néphropathie familiale avec surdité/anatomopathologie , Membrane basale/anatomopathologieRÉSUMÉ
Mural cell adhesion is important for the localization of basement membrane components during angiogenesis, and cell-cell interactions are thought to be critical for basement membrane formation. Type IV collagen, a component of the basement membrane, and non-triple helical type IV collagen α1 chain (NTH α1(IV)) co-localize in the basement membrane of neovascular vessels. However, it remains unclear how type IV collagen and NTH α1(IV) are produced around the basement membrane. In the present study, we developed a de novo angiogenesis model using human umbilical vein endothelial cell spheroids and TIG-1 fibroblast cells and demonstrated that NTH α1(IV), probably with α1(IV) chain before forming triple helix molecule, was localized in the fibroblasts in contact with vascular endothelial cells. This localization was disrupted by DAPT, a Notch signaling inhibitor. DAPT treatment also reduced type IV collagen and NTH α1(IV) secretion in TIG-1 fibroblasts, along with diminished COL4A1 and COL4A2 gene expression. Downregulation of Notch3 in TIG-1 fibroblasts decreased the secretion of type IV collagen and NTH α1(IV). Taken together, these findings suggest that heterogeneous and homogeneous intercellular Notch signaling via Notch3 induces type IV collagen and NTH α1(IV) expression in fibroblasts and contributes to basement membrane formation in neovascular vessels.
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Collagène de type IV , Cellules endothéliales de la veine ombilicale humaine , Néovascularisation physiologique , Récepteurs Notch , Transduction du signal , Collagène de type IV/métabolisme , Humains , Récepteurs Notch/métabolisme , Cellules endothéliales de la veine ombilicale humaine/métabolisme , Fibroblastes/métabolisme , Récepteur Notch3/métabolisme , Récepteur Notch3/génétique , Membrane basale/métabolisme ,RÉSUMÉ
Classical collagen type IV comprising of a heterotrimer of two collagen IV alpha 1 chains and one collagen IV alpha 2 chain is the principal type of collagen synthesized by endothelial cells (EC) and is a major constituent of vascular basement membranes. In mouse and man, mutations in genes that encode collagen IV alpha 1 and alpha 2 result in vascular dysfunction. In addition, mutations in genes that encode the Ephrin receptor B4 (EPHB4) and the p120 Ras GTPase-activating protein (RASA1) that cause increased activation of the Ras mitogen-activated protein kinase (MAPK) signaling pathway in EC result in vascular dysfunction as a consequence of impaired export of collagen IV. To understand the pathogenesis of collagen IV-related vascular diseases and phenotypes it is necessary to identify at which times collagen IV is actively synthesized by EC. For this purpose, we used CRISPR/Cas9 targeting in mice to include immediately after the terminal Col4a1 codon a sequence that specifies a P2A peptide followed by enhanced green fluorescent protein (eGFP). Analysis of eGFP expression in Col4a1-P2A-eGFP mice revealed active embryonic EC synthesis of collagen IV alpha 1 through mid to late gestation followed by a sharp decline before birth. These results provide a contextual framework for understanding the basis for the varied vascular abnormalities resulting from perturbation of EC expression and export of functional collagen IV.
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Collagène de type IV , Cellules endothéliales , Humains , Femelle , Grossesse , Cellules endothéliales/métabolisme , Collagène de type IV/génétique , Collagène de type IV/métabolisme , Protéines à fluorescence verte , Développement embryonnaire , Protéine p120 d'activation de la ras GTPase/génétique , Protéine p120 d'activation de la ras GTPase/métabolismeRÉSUMÉ
Alport syndrome is an genetic disorder that distresses the basement membrane of the kidneys and can also impact other organs, such as the cochlea of the inner ear and eyes. It is characterized by mutation causing abnormalities in the collagen within the basement membrane, which has a crucial role in the filtration process of the kidneys. These abnormalities lead to progressive kidney damage and often result in chronic kidney disease. In some cases of Alport syndrome, the abnormal collagen can also affect the cochlea in the inner ear, leading to sensorineural hearing loss. Additionally, changes in the ocular lens, named anterior lenticonus, can occur, causing vision problems. Alport syndrome can manifest differently among individuals, and its severity can vary. Some people may experience mild symptoms, while others may develop more severe kidney problems, including end-stage renal disease, which may need dialysis or kidney transplant. Treatment for Alport syndrome primarily focuses on managing its symptoms and complications. Regular monitoring of kidney function and blood pressure, along with medications to control hypertension, are crucial aspects of the management plan. In cases of severe kidney damage, kidney transplantation may be necessary. As with any medical condition, early detection and intervention can improve results and quality of life for persons with Alport syndrome. Therefore, if there is a family history of the disorder or any concerning symptoms, it is essential to seek medical attention promptly. Genetic testing can help confirm the diagnosis and identify affected family members, allowing for appropriate monitoring and management.
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Alport syndrome (AS) is a rare genetic disorder categorized by the progressive loss of kidney function, sensorineural hearing loss and eye abnormalities. It occurs due to mutations in three genes that encode for the alpha chains of type IV collagen. Globally, the disease is classified based on the pattern of inheritance into X-linked AS (XLAS), which is caused by pathogenic variants in COL4A5, representing 80% of AS. Autosomal recessive AS (ARAS), caused by mutations in either COL4A3 or COL4A4, represents 15% of AS. Autosomal dominant AS (ADAS) is rare and has been recorded in 5% of all cases due to mutations in COL4A3 or COL4A4. This review provides updated knowledge about AS including its clinical and genetic characteristics in addition to available therapies that only slow the progression of the disease. It also focuses on reported cases in Saudi Arabia and their prevalence. Moreover, we shed light on advances in genetic technologies like gene editing using CRISPR/Cas9 technology, the need for an early diagnosis of AS and managing the progression of the disease. Eventually, we provide a few recommendations for disease management, particularly in regions like Saudi Arabia where consanguineous marriages increase the risk.
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Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The JAK2V617F mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.
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X-Linked Alport Syndrome (XLAS) is an X-linked, dominant, hereditary nephropathy mainly caused by mutations in the COL4A5 gene, found on chromosome Xq22. In this study, we reported a pedigree with XLAS caused by a COL4A5 mutation. This family gave birth to a boy with XLAS who developed hematuria and proteinuria at the age of 1 year. We used next-generation sequencing (NGS) to identify mutations in the proband and his parents and confirmed the results using Sanger sequencing. This testing showed there was a single nucleotide missense variation, c.3659G>A (p.Gly1220Asp) (NM_033380.3), in the COL4A5 gene. To prevent the inheritance of the syndrome, we used eight embryos for trophoblast biopsy after assisted reproductive technology treatment, and whole genome amplification (WGA) was performed using multiple annealing and looping-based amplification cycles (MALBAC). Embryos were subjected to Preimplantation Genetic Testing (PGT) procedures, including Sanger sequencing, NGS-based single nucleotide polymorphism (SNP) haplotype linkage analysis, and chromosomal copy number variation (CNV) analysis. The results showed that three embryos (E1, E2, and E4) were free of CNV and genetic variation in the COL4A5 gene. Embryo E1 (4AA) was transferred after consideration of the embryo growth rate, morphology, and PGT results. Prenatal diagnosis in the second trimester showed that the fetus had a normal karyotype and did not carry the COL4A5 mutation (c.3659G>A). Ultimately, a healthy boy was born and did not carry the pathogenic COL4A5 mutation, which indicated that PGT prevented the intergenerational transmission of the causative mutation of XLAS.
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X-linked Alport syndrome is a hereditary progressive renal disease resulting from the disruption of collagen α3α4α5 (IV) heterotrimerization caused by pathogenic variants in the COL4A5 gene. This study aimed to report a male case of X-linked Alport syndrome with a mild phenotype accompanied by an atypical expression pattern of type IV collagen α5 [α5 (IV)] chain in glomerulus. A 38-year-old male presented with proteinuria (2.3 g/day) and hematuria. He has been detected urinary protein and occult blood since childhood. A renal biopsy was performed at the age of 29 years; however, a diagnosis of Alport syndrome was not considered. A renal biopsy 9 years later revealed diffuse thinning and lamellation of the glomerular basement membrane. Α staining for α5 (IV) revealed a normal expression pattern in the glomerular basement membrane and a complete negative expression in Bowman's capsule and distal tubular basement membrane. Using next-generation sequencing, we detected a COL4A5 missense variant within exon 35 (NM_000495.5: c.3088G>A, p. G1030S). The possibility of X-linked Alport syndrome should be considered when negative expression of α5 (IV) staining on Bowman's capsule was observed.