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Objectives: Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis and lack of biomarkers. A rich desmoplastic tumor stroma is considered a hallmark of PDAC and previous studies have indicated upregulated expression of collagen VI (COL6) in PDAC. COL6 is shown to associate with prognosis in many cancers but has been less extensively studied in PDAC., Materials and Methods: The expression of COL6 was analyzed by immunohistochemistry in tissue microarrays containing resected tumor tissue samples from PDAC patients (n = 164). Significance of COL6 was estimated with Kaplan-Meier survival estimates and multivariable Cox regression analysis. COL6 protein and mRNA expression patterns were further investigated in publicly available datasets., Results: There were no statistically significant ( P < 0.05) differences in survival when comparing high and low protein expression of any of the analyzed COL6 α-chains (α1(VI): hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.64-1.28; α2(VI): HR 1.28, 95% CI 0.86-1.89; α3(VI): HR 0.91, 95% CI 0.64-1.29). Similar results were obtained when assessing public data from the Cancer Proteome Atlas, Clinical Proteomic Tumor Analysis Consortium, and The Cancer Genome Atlas., Conclusions: In contrast with previous studies and some other cancers, we did not find any association of COL6 tissue expression and PDAC survival., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: The pathophysiology of nonsyndromic craniosynostosis remains poorly understood. The authors seek to understand the cause of this condition with a specific focus on how osteoclasts may contribute to craniosynostosis. Here, the authors characterize proteins differentially expressed in patent and fused cranial sutures by comparing their respective proteomes., Methods: Fused and patent suture samples were obtained from craniosynostotic patients undergoing surgery at a single academic medical center. Extracted protein from samples was interrogated using mass spectrometry. Differential protein expression was determined using maximum likelihood-based G-test with a q-value cutoffs of 0.5 after correction for multiple hypothesis testing. Immunolocalization of lead protein candidates was performed to validate proteomic findings. In addition, quantitative polymerase chain reaction analysis of corresponding gene expression of proteins of interest was performed., Results: Proteins differentially expressed in patent versus fused sutures included collagen 6A1 (Col6A1), fibromodulin, periostin, aggrecan, adipocyte enhancer-binding protein 1, and osteomodulin (OMD). Maximum likelihood-based G-test suggested that Col6A1, fibromodulin, and adipocyte enhancer-binding protein 1 are highly expressed in patent sutures compared with fused sutures, whereas OMD is up-regulated in fused sutures compared with patent sutures. These results were corroborated by immunohistochemistry. Quantitative polymerase chain reaction data point to an inverse relationship in proteins of interest to RNA transcript levels, in prematurely fused and patent sutures that potentially describes a feedback loop mechanism., Conclusions: Proteome analysis validated by immunohistochemistry may provide insight into the mechanism of cranial suture patency and disease from an osteoclast perspective. The authors results suggest a role of inflammatory mediators in nonsyndromic craniosynostosis. Col6A1 may aid in the regulation of suture patency, and OMD may be involved in premature fusion. Additional validation studies are required.

Background: To identify gastric cancer (GC)-associated genes and transcription factors (TFs) using RNA-sequencing (RNA-seq) data of Asians., Materials and Methods: The RNA-seq data (GSE36968) were downloaded from Gene Expression Omnibus database, including 6 noncancerous gastric tissue samples, 5 stage I GC samples, 5 stage II GC samples, 8 stage III GC samples, and 6 stage IV GC samples. The gene expression values in each sample were calculated using Cuffdiff. Following, stage-specific genes were identified by 1-way analysis of variance and hierarchical clustering analysis. Upstream TFs were identified using Seqpos. Besides, functional enrichment analysis of stage-specific genes was performed by DAVID. In addition, the underlying protein-protein interactions (PPIs) information among stage IV-specific genes were extracted from STRING database and PPI network was constructed using Cytoscape software., Results: A total of 3576 stage-specific genes were identified, including 813 specifically up-regulated genes in the normal gastric tissues, 2224 stage I and II-specific genes, and 539 stage IV-specific genes. Also, a total of 9 and 11 up-regulated TFs were identified for the stage I and II-specific genes and stage IV-specific genes, respectively. Functional enrichment showed SPARC, MMP17, and COL6A3 were related to extracellular matrix. Notably, 2 regulatory pathways HOXA4-GLI3-RUNX2-FGF2 and HMGA2-PRKCA were obtained from the PPI network for stage IV-specific genes. In the PPI network, TFs HOXA4 and HMGA2 might function via mediating other genes., Conclusion: These stage-specific genes and TFs might act in the pathogenesis of GC in Asians., Competing Interests: The authors have no funding and conflicts of interest to disclose.

Rationale: We previously reported that type VI collagen deposition increases in the infarcted myocardium in vivo. To date, a specific role for this nonfibrillar collagen has not been explored in the setting of myocardial infarction (MI)., Objective: To determine whether deletion of type VI collagen in an in vivo model of post-MI wound healing would alter cardiac function and remodeling in the days to weeks after injury., Methods and Results: Wild-type and Col6a1(-/-) mice were subjected to MI, followed by serial echocardiographic and histological assessments. At 8 weeks after MI, infarct size was significantly reduced, ejection fraction was significantly preserved (43.9% ± 3.3% versus 29.1% ± 4.3% for wild-type), and left ventricular chamber dilation was attenuated in the Col6a1(-/-) MI group (25.8% ± 7.9% increase versus 62.6% ± 16.5% for wild-type). The improvement in cardiac remodeling was evident as early as 10 days after MI in the Col6a1(-/-) mice. Myocyte apoptosis within the infarcted zones was initially greater in the Col6a1(-/-) group 3 days after MI, but by day 14 this was significantly reduced. Collagen deposition also was reduced in the infarcted and remote areas of the Col6a1(-/-) hearts. The reductions in chronic myocyte apoptosis and fibrosis are critical events leading to improved long-term remodeling and functional outcomes., Conclusions: These unexpected results demonstrate for the first time that deletion of type VI collagen in this knockout model plays a critical protective role after MI by limiting infarct size, chronic apoptosis, aberrant remodeling, and fibrosis, leading to preservation of cardiac function.

Background: Bethlem myopathy is a well-defined clinical entity among collagen VI disorders, featuring proximal muscle weakness and contractures of the fingers, wrists, and ankles. It is an early-onset, slowly progressive, and relatively mild disease, invariably associated to date with heterozygous dominant mutations in the 3 collagen VI genes. We have characterized the clinical, laboratory, and genetic features of autosomal recessive Bethlem myopathy in 2 unrelated patients., Methods: This study is based on clinical, histochemical, immunocytochemical, and electron microscope evaluation of the muscle and dermal fibroblasts, CT imaging of the muscles, and biochemical and molecular analysis., Results: Both patients carry a truncating COL6A2 mutation (Q819X; R366X) associated with missense changes in the partnering allele lying within the C2 domain of the alpha2(VI) chain (D871N; R843W-R830Q). They show decreased amounts of collagen VI in the basal lamina of muscle fibers and in dermal fibroblast cultures and altered behavior of collagen VI tetramers. Biochemical studies supported the pathogenic effect of identified amino acid substitutions, which involve strictly conserved residues., Conclusions: The reported patients illustrate the occurrence of Bethlem myopathy with a recessive mode of inheritance. This observation completes the hereditary pattern in collagen VI myopathies with both Ullrich congenital muscular dystrophy and Bethlem myopathy underlined by either recessive or dominant effecting mutations. This finding has relevant implications for genetic counseling and molecular characterization of patients with Bethlem myopathy, as well as for genotype-phenotype correlations in collagen VI disorders.

Objective: To determine the clinical and molecular features of a new phenotype related to collagen VI myopathies., Methods: We examined two patients belonging to a consanguineous family affected by myosclerosis myopathy, screened for mutations of collagen VI genes, and performed a detailed biochemical and morphologic analysis of the muscle biopsy and cultured fibroblasts., Results: The patients had a novel homozygous nonsense COL6A2 mutation (Q819X); the mutated messenger RNA escaped nonsense-mediated decay and was translated into a truncated alpha2(VI) chain, lacking the sole C2 domain. The truncated chain associated with the other two chains, giving rise to secreted collagen VI. Monomers containing the truncated chain were assembled into dimers, but tetramers were almost absent; secreted collagen VI was quantitatively reduced and structurally abnormal in cultured fibroblasts. Mutated collagen did not correctly localize in the basement membrane of muscle fibers and was absent in the capillary wall. Ultrastructural analysis of muscle showed an unusual combination of basement membrane thickening and duplication, and increased number of pericytes., Conclusions: This familial case has the characteristic features of myosclerosis myopathy and carries a homozygous COL6A2 mutation responsible for a peculiar pattern of collagen VI defects. Our study demonstrates that myosclerosis myopathy should be considered a collagen VI disorder allelic to Ullrich congenital muscular dystrophy and Bethlem myopathy.

Objective: Mutations in COL6A1, COL6A2, and COL6A3, the genes that encode the extracellular matrix component collagen VI, lead to Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). Unlike UCMD, BM is difficult to diagnose because of its clinical overlap with other contractural phenotypes and the lack of sensitivity of standard muscle biopsy immunohistochemical diagnostic techniques., Methods: We appraised two potential techniques for the diagnosis of BM: dual immunofluorescence (IF) for collagen VI and basal lamina-located perlecan in muscle, and immunofluorescent labeling of collagen VI in skin biopsy-derived fibroblast cultures, which was conducted in 40 patients by blinded investigators and correlated with genetic findings., Results: Dual IF was indistinguishable from normal controls in most BM patients. However, abnormalities in the IF labeling pattern of collagen VI were detected in more than 78% of genetically confirmed BM patient fibroblast cell lines. In addition, in a group of patients with unknown diagnosis studied prospectively, the fibroblast IF technique was highly predictive of the presence of a COL6A mutation, providing a positive predictive value of 75%, a sensitivity and negative predictive value of 100%, and a specificity of 63%., Conclusions: Immunofluorescent labeling of collagen VI in fibroblast cultures is a useful addition to current diagnostic services for Bethlem myopathy (BM). It can be used to guide molecular genetic testing, the gold standard diagnostic technique for BM, in a cost-effective and time-saving manner.

Purpose: To compare immunohistochemical findings in human donor corneas after successful laser in situ keratomileusis (LASIK) without clinical complications with a recently established human LASIK in vitro model., Methods: Donor corneas with prior LASIK treatment were investigated. Cryostat sections were stained immunohistochemically for collagen types I, III, and VI and laminin and fibronectin., Results: With light microscopy, the interface of the LASIK flap could hardly be detected. In all samples, fibronectin was consistently detected along the entire extent of the surgical wound. In contrast, collagen type III and laminin only stained the superficial portion of the LASIK incision site. Staining for collagen types I and VI showed no changes after LASIK., Conclusion: Histologic findings in donor corneas with prior LASIK treatment confirm histologic observations in a recently introduced human organ culture LASIK model. This strengthens the reliability of the latter LASIK model for further studies concerning wound healing after LASIK surgery.

Background: Ullrich congenital muscular dystrophy (UCMD) is a form of merosin-positive congenital muscular dystrophy characterized by proximal contractures, distal laxity, rigidity of the spine, and respiratory complications. Recently, a deficiency of collagen VI on muscle and skin biopsy together with recessive mutations in the collagen 6A2 gene were reported in three families with UCMD. However, the clinical spectrum, frequency, and level of heterogeneity of this disorder are not known., Subjects and Methods: The authors studied 15 patients (aged 3 to 23.6 years) with a clinical diagnosis of UCMD. Linkage analysis to the three collagen VI genes was performed in all informative families (n = 7), whereas immunohistochemical analysis of collagen VI expression in muscle was performed in the remaining cases., Results: An immunocytochemical reduction of collagen VI was observed in six patients. Three of the six patients belonged to informative families, and haplotype analysis clearly suggested linkage to the COL6A1/2 locus in two cases and to the COL6A3 loci in the third case. In the remaining nine patients, primary collagen VI involvement was excluded based on either the linkage analysis (four families) or considered unlikely based on normal immunolabeling of collagen VI. Age and presentation at onset, the distribution and severity of weakness and contractures, and the frequency of nonambulant patients were similar in the patients with and without collagen VI involvement. Distal laxity, rigidity of the spine, scoliosis, failure to thrive, and early and severe respiratory impairment were found in all patients by the end of the first decade of life, irrespective of their maximum motor functional ability or their collagen status., Conclusions: These results suggest that collagen VI involvement is relatively common in UCMD (40%); however, the role of this molecule was excluded in a number of cases, suggesting genetic heterogeneity of this condition.