A humanized knock-in Col6a1 mouse recapitulates a deep-intronic splice-activating variant

Antisense therapeutics such as splice-modulating antisense oligonucleotides (ASOs) are promising tools to treat diseases caused by splice-altering intronic variants. However, their testing in animal models is hampered by the generally poor sequence conservation of the intervening sequences between human and other species. Here we aimed to model in the mouse a recurrent, deep-intronic, splice-activating, COL6A1 variant, associated with a severe form of Collagen VI-related muscular dystrophies (COL6-RDs), for the purpose of testing human-ready antisense therapeutics in vivo. The variant, c.930+189C>T, creates a donor splice site and inserts a 72-nt-long pseudoexon, which, when translated, acts in a dominant-negative manner, but which can be skipped with ASOs. We created a unique humanized mouse allele (designated as "h"), in which a 1.9 kb of the mouse genomic region encoding the amino-terminus (N-) of the triple helical (TH) domain of collagen a1(VI) was swapped for the human orthologous sequence. In addition, we also created an allele that carries the c.930+189C>T variant on the same humanized knock-in sequence (designated as "h+189T"). We show that in both models, the human exons are spliced seamlessly with the mouse exons to generate a chimeric mouse-human collagen a1(VI) protein. In homozygous Col6a1 h+189T/h+189T mice, the pseudoexon is expressed at levels comparable to those observed in heterozygous patients' muscle biopsies. While Col6a1h/h mice do not show any phenotype compared to wildtype animals, Col6a1 h/h+189T and Col6a1 h+189T/h+189T mice have smaller muscle masses and display grip strength deficits detectable as early as 4 weeks of age. The pathogenic h+189T humanized knock-in mouse allele thus recapitulates the pathogenic splicing defects seen in patients' biopsies and allows testing of human-ready precision antisense therapeutics aimed at skipping the pseudoexon. Given that the COL6A1 N-TH region is a hot-spot for COL6-RD variants, the humanized knock-in mouse model can be utilized as a template to introduce other COL6A1 pathogenic variants. This unique humanized mouse model thus represents a valuable tool for the development of antisense therapeutics for COL6-RDs.

Retrospective clinical and genetic analysis of COL6-RD patients with a long-term follow-up at a single French center

Collagen type VI-related dystrophies (COL6-RD) are rare diseases with a wide phenotypic spectrum ranging from severe Ullrich's congenital muscular dystrophy Ullrich congenital muscular dystrophy to much milder Bethlem myopathy Both dominant and recessive forms of COL6-RD are caused by pathogenic variants in three collagen VI genes (COL6A1, COL6A2 and COL6A3). The prognosis of these diseases is variable and difficult to predict during early disease stages, especially since the genotype-phenotype correlation is not always clear. For this reason, studies with long-term follow-up of patients with genetically confirmed COL6-RD are still needed. In this study, we present phenotypic and genetic data from 25 patients (22 families) diagnosed with COL6-RD and followed at a single French center, in both adult and pediatric neurology departments. We describe three novel pathogenic variants and identify COL6A2:c.1970-9G>A as the most frequent variant in our series (29%). We also observe an accelerated progression of the disease in a subgroup of patients. This large series of rare disease patients provides essential information on phenotypic variability of COL6-RD patients as well as on frequency of pathogenic COL6A gene variants in Southern France, thus contributing to the phenotypic and genetic description of Collagen type VI-related dystrophies.

New Clinical and Immunofluoresence Data of Collagen VI-Related Myopathy: A Single Center Cohort of 69 Patients

Pathogenetic mechanism recognition and proof-of-concept clinical trials were performed in our patients affected by collagen VI-related myopathies. This study, which included 69 patients, aimed to identify innovative clinical data to better design future trials. Among the patients, 33 had Bethlem myopathy (BM), 24 had Ullrich congenital muscular dystrophy (UCMD), 7 had an intermediate phenotype (INTM), and five had myosclerosis myopathy (MM). We obtained data on muscle strength, the degree of contracture, immunofluorescence, and genetics. In our BM group, only one third had a knee extension strength greater than 50% of the predicted value, while only one in ten showed similar retention of elbow flexion. These findings should be considered when recruiting BM patients for future trials. All the MM patients had axial and limb contractures that limited both the flexion and extension ranges of motion, and a limitation in mouth opening. The immunofluorescence analysis of collagen VI in 55 biopsies from 37 patients confirmed the correlation between collagen VI defects and the severity of the clinical phenotype. However, biopsies from the same patient or from patients with the same mutation taken at different times showed a progressive increase in protein expression with age. The new finding of the time-dependent modulation of collagen VI expression should be considered in genetic correction trials.

Homozygous splice variant (c.1741-6G>A) of the COL6A1 gene in three patients with Ullrich congenital muscular dystrophy

The three major collagen VI genes: COL6A1, COL6A2, and COL6A3 encode microfibrillar components of extracellular matrices in multiple tissues including muscles and tendons. Pathogenic variants in the collagen VI genes cause collagen VI-related dystrophies representing a continuum of conditions from Bethlem myopathy at the milder end to Ullrich congenital muscular dystrophy at the more severe end. Here we describe a pathogenic variant in the COL6A1 gene (NM_001848.3; c.1741-6G>A) found in homozygosity in three patients with Ullrich congenital muscular dystrophy. The patients suffered from severe muscle impairment characterised by proximal weakness, distal hyperlaxity, joint contractures, wheelchair-dependency, and use of nocturnal non-invasive ventilation. The pathogenicity was verified by RNA analyses showing that the variant induced aberrant splicing leading to a frameshift and loss of function. The analyses were in line with immunocytochemistry studies of patient-derived skin fibroblasts and muscle tissue demonstrating impaired secretion of collagen VI into the extracellular matrix. Thereby, we add the variant c.1741-6G>A to the list of pathogenic, recessive, splice variants in COL6A1 causing Ullrich congenital muscular dystrophy. The variant is listed in ClinVar as of "uncertain significance" and "likely benign" and may presumably have been overlooked in other patients.

Collagen VI in the Musculoskeletal System

Collagen VI exerts several functions in the tissues in which it is expressed, including mechanical roles, cytoprotective functions with the inhibition of apoptosis and oxidative damage, and the promotion of tumor growth and progression by the regulation of cell differentiation and autophagic mechanisms. Mutations in the genes encoding collagen VI main chains, COL6A1, COL6A2 and COL6A3, are responsible for a spectrum of congenital muscular disorders, namely Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM) and myosclerosis myopathy (MM), which show a variable combination of muscle wasting and weakness, joint contractures, distal laxity, and respiratory compromise. No effective therapeutic strategy is available so far for these diseases; moreover, the effects of collagen VI mutations on other tissues is poorly investigated. The aim of this review is to outline the role of collagen VI in the musculoskeletal system and to give an update about the tissue-specific functions revealed by studies on animal models and from patients' derived samples in order to fill the knowledge gap between scientists and the clinicians who daily manage patients affected by collagen VI-related myopathies.

High expression of COL6A1 predicts poor prognosis and response to immunotherapy in bladder cancer

Extracellular matrix (ECM), as an important framework for tumor microenvironment, plays important roles in many critical processes, including tumor growth, invasion, immune suppression, and drug resistance. However, few biomarkers of ECM-related genes (ERGs) have been developed for prognosis prediction and clinical treatment of bladder cancer (BC) patients. Bioinformatics analysis and LC-MS/MS analysis were used to screen differentially expressed ERGs in BC. Multivariate Cox regression analysis and Lasso regression analysis were used to construct and validate an ERGs-based prognostic prediction model for BC. Immunohistochemistry was used to detect the protein expression of hub gene-COL6A1 in BC patients. Using bioinformatics analysis from The Cancer Genome Atlas (TCGA) database and proteomic analysis from our BC cohort, we constructed and validated an effective prognostic prediction model for BC patients based on four differentially expressed ERGs (MAP1B, FBN1, COL6A1, and MFAP5). Moreover, we identified human collagen VI-COL6A1 was a hub gene in this prognostic prediction model and found that COL6A1 was closely related to malignancy progression, prognosis, and response to PD-1 inhibitor immunotherapy in BC. Our findings highlight the satisfactory predictive value of ECM-related prognostic models in BC and suggested that COL6A1 may be a potential biomarker in predicting malignant progression, prognosis, and efficacy of immunotherapy in BC.

A Schematic Approach to Defining the Prevalence of COL VI Variants in Five Years of Next-Generation Sequencing

OBJECTIVE

To define the prevalence of variants in collagen VI genes through a next-generation sequencing (NGS) approach in undiagnosed patients with suspected neuromuscular disease and to propose a diagnostic flowchart to assess the real pathogenicity of those variants.

METHODS

In the past five years, we have collected clinical and molecular information on 512 patients with neuromuscular symptoms referred to our center. To pinpoint variants in COLVI genes and corroborate their real pathogenicity, we sketched a multistep flowchart, taking into consideration the bioinformatic weight of the gene variants, their correlation with clinical manifestations and possible effects on protein stability and expression.

RESULTS

In Step I, we identified variants in COLVI-related genes in 48 patients, of which three were homozygous variants (Group 1). Then, we sorted variants according to their CADD score, clinical data and complementary studies (such as muscle and skin biopsy, study of expression of COLVI on fibroblast or muscle and muscle magnetic resonance). We finally assessed how potentially pathogenic variants (two biallelic and 12 monoallelic) destabilize COL6A1-A2-A3 subunits. Overall, 15 out of 512 patients were prioritized according to this pipeline. In seven of them, we confirmed reduced or absent immunocytochemical expression of collagen VI in cultured skin fibroblasts or in muscle tissue.

CONCLUSIONS

In a real-world diagnostic scenario applied to heterogeneous neuromuscular conditions, a multistep integration of clinical and molecular data allowed the identification of about 3% of those patients harboring pathogenetic collagen VI variants.

P4HA1 Regulates CD31 via COL6A1 in the Transition of Glioblastoma Stem-Like Cells to Tumor Endothelioid Cells

Glioblastoma multiforme (GBM) is a common intracranial malignancy characterized by abundant and aberrant vasculature. The efficiency of existing antivascular treatments remains unsatisfactory. The transition of glioblastoma stem-like cells (GSCs) into tumor endothelioid cells (ECs) has been thought to cause glioma neovascularization and anti-angiogenesis tolerance, but the mechanisms regulating glioma transdifferentiation remains unclear. Our previous study found that P4HA1 regulates GSCs vascular mimicry in a hypoxic microenvironment, but the detailed molecular mechanism has not been determined. In this study, candidate protein COL6A1 was screened by mass spectrometry. In vitro experiments show that P4HA1 regulates the expression of CD31 via COL6A1, with the levels of expression of P4HA1, COL6A1 and the vascular endothelial molecular markers CD31 showing positive correlations in vivo assay. Altering the expression of P4HA1 in GSCs altered the expression of COL6A1 and CD31, thereby inducing glioma angiogenesis. In conclusion, this study revealed that the P4HA1/COL6A1 axis modulates the transdifferentiation process of GSCs into ECs. Interrupting this signaling axis can inhibit glioma angiogenesis, suggesting that this axis may be a novel target for antivascular therapy in patients with glioma.

CRISPR/Cas9-Mediated Allele-Specific Disruption of a Dominant COL6A1 Pathogenic Variant Improves Collagen VI Network in Patient Fibroblasts

Collagen VI-related disorders are the second most common congenital muscular dystrophies for which no treatments are presently available. They are mostly caused by dominant-negative pathogenic variants in the genes encoding α chains of collagen VI, a heteromeric network forming collagen; for example, the c.877G>A; p.Gly293Arg COL6A1 variant, which alters the proper association of the tetramers to form microfibrils. We tested the potential of CRISPR/Cas9-based genome editing to silence or correct (using a donor template) a mutant allele in the dermal fibroblasts of four individuals bearing the c.877G>A pathogenic variant. Evaluation of gene-edited cells by next-generation sequencing revealed that correction of the mutant allele by homologous-directed repair occurred at a frequency lower than 1%. However, the presence of frameshift variants and others that provoked the silencing of the mutant allele were found in >40% of reads, with no effects on the wild-type allele. This was confirmed by droplet digital PCR with allele-specific probes, which revealed a reduction in the expression of the mutant allele. Finally, immunofluorescence analyses revealed a recovery in the collagen VI extracellular matrix. In summary, we demonstrate that CRISPR/Cas9 gene-edition can specifically reverse the pathogenic effects of a dominant negative variant in COL6A1.

Identification of differentially expressed genes using microarray analysis and COL6A1 induction of bone metastasis in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a major cause of cancer-associated mortality worldwide, and bone metastasis is the most prevalent event observed in patients with advanced NSCLC. However, the pathogenesis of bone metastases has not been fully elucidated. In the present study, differentially expressed genes (DEGs) were identified by gene expression microarray analysis of NSCLC tissue samples with or without bone metastases. Subsequently, collagen type 6A1 (COL6A1) was chosen as the target gene through Ingenuity Pathway Analysis and reverse transcription-quantitative (RT-q) PCR validation of the top eight DEGs. COL6A1 was overexpressed or knocked down, and the proliferation and invasion of NSCLC cells was assessed using Cell Counting Kit-8, colony formation and Transwell invasion assays. Additionally, the osteogenic capacity of HOB and hES-MP 002.5 cells was assessed using RT-qPCR, western blotting, Alizarin Red and alkaline phosphatase staining. A total of 364 DEGs were identified in NSCLC tissues with bone metastases compared with NSCLC tissues without bone metastases, including 140 upregulated and 224 downregulated genes. Gene Ontology analysis results demonstrated that the upregulated and downregulated genes were primarily enriched in 'cellular process', 'metabolic process' and 'biological regulation'. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the upregulated genes were primarily enriched in 'cysteine and methionine metabolism', 'oxidative phosphorylation' and 'ribosome', whereas the downregulated genes were primarily enriched in the 'transcriptional misregulation in cancer', 'ribosome' and 'mitophagy-animal' pathways. COL6A1 was highly expressed in NSCLC tissue samples with bone metastases. Functionally, COL6A1 overexpression induced the proliferation and invasion of HARA cells, and its knockdown inhibited the proliferation and invasion of HARA-B4 cells. Finally, it was demonstrated that HOB and hES-MP 002.5 cells exhibited osteogenic capacity, and overexpression of COL6A1 in HARA cells increased the adhesion of these cells to the osteoblasts, whereas knockdown of COL6A1 in HARA-B4 cells reduced their adhesive ability. In conclusion, COL6A1 may serve as a potential diagnostic marker and therapeutic target for bone metastasis in NSCLC.

Association analysis and functional study of COL6A1 single nucleotide polymorphisms in thoracic ossification of the ligamentum flavum in the Chinese Han population

PURPOSE

Genetic factors play a crucial role in thoracic ossification of the ligamentum flavum (TOLF). This study aimed to better understand the association between single nucleotide polymorphisms (SNP) in functional regions of the collagen VI, alpha 1 gene (COL6A1) and TOLF, and to confirm COL6A1 as a TOLF susceptibility gene.

METHODS

Ten tag SNPs in COL6A1 were genotyped using the SNaPshot assay, and allele and genotype frequencies were compared between TOLF patients and control individuals. The function of SNPs associated with disease was studied. For COL6A1 promoter SNPs, the transcriptional activity of each haplotype was determined by luciferase reporter assays. For COL6A1 exonic SNPs, the effect of nucleotide substitutions on COL6A1 expression was determined by western blotting. COL6A1 mRNA expression in ligamentum flavum tissues from TOLF patients with different genotypes was examined using reverse transcription real-time PCR.

RESULTS

Four SNPs were associated or possibly associated with TOLF, with higher pathogenic allele and genotype frequencies seen in TOLF patients compared with controls. The rs17551710/rs7671-GG/GG genotype appeared to be related to disease severity. Nucleotide substitutions at rs17551710 and rs7671 increased COL6A1 transcriptional activity and nucleotide substitutions at rs1053312 and rs13051496 increased COL6A1 protein expression. COL6A1 mRNA expression was significantly up-regulated in individuals with rs17551710/rs7671-GG/GG and rs1053312/rs13051496-AA+AG/CC genotypes compared with other genotypes.

CONCLUSION

SNPs in the COL6A1 promoter and exonic regions are associated with TOLF in the Chinese Han population, and lead to up-regulated COL6A1 expression. We confirmed COL6A1 as a TOLF susceptibility gene that may be involved in TOLF pathology.

Identification of COL6A1 as the Key Gene Associated with Antivascular Endothelial Growth Factor Therapy in Glioblastoma Multiforme

Background: Vascular endothelial growth factors (VEGFs) are important for glioblastoma multiforme (GBM) growth and development. However, the effects of VEGF-targeting drugs in primary GBM remain poorly understood. Aim: We aimed to explore the key genes correlated with VEGF expression and prognosis and elucidate their potential implications in GBM anti-VEGF therapy. Materials and Methods: RNA-seq data with the corresponding clinicopathological information was retrieved from The Cancer Genome Atlas and the Chinese Glioma Genome Atlas. Weighted gene coexpression network analyses was performed on differentially expressed genes to construct coexpression modules and investigate their correlation with VEGFs. Functional enrichment analyses were performed based on the coexpressed genes from the most promising modules. CytoHubba and Kaplan-Meier analyses were implemented to identify the key genes in the modules of interest. The oncomine database, quantitative reverse transcription PCR, and the Human Protein Atlas were used to investigate the expression characteristics of the identified key genes. Results: Four modules (cyan, green, purple, and tan) correlated significantly with VEGF expression. Enrichment analyses suggested that extracellular matrix-receptor interaction, growth factor binding, and the PI3K-Akt pathways were involved in VEGF expression. Four hub genes (COL6A1, SNRPG, COL3A1, and AHI1) associated with VEGF were identified. Among them, COL6A1 was regarded as the key gene associated with anti-VEGF therapy. Further, COL6A1 was upregulated in GBM compared to that in normal brain tissues. COL6A1 overexpression was associated with a poor prognosis. Conclusion: COL6A1 was identified as the key gene associated with anti-VEGF therapy and may provide novel insight into GBM targeted therapy.

Tumor-associated macrophages promote the metastasis and growth of non-small-cell lung cancer cells through NF-κB/PP2Ac-positive feedback loop

Non‐small‐cell lung cancer (NSCLC), with its aggressive biological behavior, is one of the most diagnosed cancers. Tumor‐associated inflammatory cells play important roles in the interaction between chronic inflammation and lung cancer, however the mechanisms involved are far from defined. In the present study, by developing an orthotopic NSCLC mouse model based on chronic inflammation, we proved that an inflammatory microenvironment accelerated the growth of orthotopic xenografts in vivo. Tumor‐associated macrophages, the most abundant population of inflammatory cells, were identified. Treatment with macrophage‐conditioned medium (MCM) promoted the growth and migration of NSCLC cells. Using bioinformatics analysis, we identified downregulated PP2Ac expression in NSCLC cells upon treatment with MCM. We further confirmed that this downregulation was executed in an NF‐κB pathway‐dependent manner. As IκB kinase (IKK) has been proved to be a substrate of PP2Ac, inhibition on PP2Ac could result in amplification of NF‐κB pathway signaling. Overexpression of PP2Ac, or the dominant‐negative forms of IKK or IκB, attenuated the acceleration of growth and metastasis by MCM. Using bioinformatics analysis, we further identified that CXCL1 and COL6A1 could be downstream of NF‐κB/PP2Ac pathway. Luciferase assay and ChIP assay further confirmed the location of response elements on the promoter regions of CXCL1 and COL6A1. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted proliferation and migration.

A novel variant in the COL6A1 gene causing Ullrich congenital muscular dystrophy in a consanguineous family: a case report

Background

Collagen VI-related dystrophies are a subtype of congenital muscular dystrophy caused by pathogenic variants in COL6A1, COL6A2 or COL6A3 genes affecting skeletal muscles and connective tissue. The clinical phenotype ranges from the milder Bethlem myopathy to the severe Ullrich congenital muscular dystrophy (UCMD). Herein, we report the first consanguineous Sri Lankan family with two children affected with UCMD due to a novel variant in the COL6A1 gene.

Case presentation

Two sisters, aged 10-years and 7-years, presented with progressive, bilateral proximal muscle weakness. Both probands had delayed motor milestones and demonstrated difficulty in standing from a squatting position, climbing stairs and raising arms above the shoulders. Cognitive, language and social development were age appropriate. Examination showed proximal muscle weakness of the upper and lower extremities and hyperlaxity of the wrist and fingers in both with some variability in clinical severity noted between the two siblings. Serum creatine kinase levels were elevated, and electromyography showed low polyphasic motor unit potentials in the 10-year-old and myopathic features with short duration motor unit potentials with no polyphasia in the 7-year-old. Whole exome sequencing (WES) was performed and a novel, homozygous missense, likely pathogenic variant in exon 25 of COL6A1 gene [NM_001848: c.1667G > T;NP_001839.2:p.Gly556Val] was identified in both probands. This variant was validated by Sanger sequencing in proband 1 as well as proband 2, and the parents and an unaffected sibling were found to be heterozygote carriers for the same variant.

Conclusions

The findings in this family add to the expanding number of COL6A1 variants identified and provides a better understanding of the genotype-phenotype correlations associated with UCMD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02134-7.

Effect of Glucose Variability on Pancreatic Cancer Through Regulation of COL6A1

Background

Pancreatic cancer (PC), a devastating cancer worldwide, remains dismal prognosis due to its clinical elusiveness, especially in relation to diabetes mellitus (DM). The study aims to investigate the effect of glucose variability on COL6A1 in PC cancer cells and the prognostic potential of COL6A1 for PC patient associated with DM.

Methods

After PC cancer cell lines of AsPC-1 and BxPC-3 were treated with hyperglycemia and hypoglycemia, Giemsa staining and Transwell chamber were performed to assay plate clone formation, migration and invasion. Expressions of COL6A1 of PC cancer cell lines under different extracellular glucose levels were detected by qRT-PCR and Western blotting. The level of COL6A1 expression in PC patients with/without DM was further observed with immunohistochemistry. The prognostic impact of COL6A1 on PC patients with DM was assessed by Kaplan–Meier survival curve analysis.

Results

Hyperglycemia promoted proliferation, migration and invasion of PC cancer cells compared with hypoglycemia. Glucose variability could regulate expression of COL6A1 in PC cancer cells, both Col6a1 mRNA and COL6A1 protein upregulated in cancer cells cultured with hyperglycemic than that with hypoglycemic. The level of COL6A1 expression was higher in PC patients with DM than that without DM. Besides, COL6A1 was significantly associated with the clinical prognosis of PC patients with DM, higher COL6A1 leading to lower overall survival (OS).

Conclusion

Glucose variability had effect on PC cancer cells through regulation of COL6A1. Accordingly, COL6A1 was associated with poorer prognosis in PC patients with DM.

H3K27 acetylation activated-COL6A1 promotes osteosarcoma lung metastasis by repressing STAT1 and activating pulmonary cancer-associated fibroblasts

Background: Collagen type VI alpha 1 (COL6A1) has been found to be dysregulated in several human malignancies. However, the role of COL6A1 in osteosarcoma (OS) progression remains largely unclear. Here, we aimed to explore the clinical significance and biological involvement of COL6A1 in the OS cell migration and invasion. Material and Methods: We used immunohistochemistry, qRT-PCR and western blot to detect the expression of COL6A1 in 181 OS patient samples. Chromatin immunoprecipitation (ChIP) and PCR were carried out to verify the regulatory interaction of p300, c-Jun and COL6A1 promoter. The invasion and migration function of COL6A1 in OS was detected in vitro and in vivo. RNA sequence was performed to detect the downstream pathway of COL6A1, and then co-immunoprecipitation (co-IP), ubiquitination assays and rescue experiments were performed to determine the regulatory effect of COL6A1 and signal transducers and activators of transcription (STAT1). Exosomes derived from OS cell lines were assessed for the ability to promote cancer progression by co-cultured assay and exosomes tracing. Results: COL6A1 was commonly upregulated in OS tissues, especially in lung metastasis tissues, which was associated with a poor prognosis. c-Jun bound p300 increased the enrichment of H3K27ac at the promoter region of the COL6A1 gene, which resulted in the upregulation of COL6A1 in OS. Overexpression of COL6A1 promoted OS cell migration and invasion via interacting with SOCS5 to suppress STAT1 expression and activation in an ubiquitination and proteasomal degradation manner. Most interestingly, we found that exosomal COL6A1 derived from OS cells convert normal fibroblasts to cancer-associated fibroblasts (CAFs) by secreting pro-inflammatory cytokines, including IL-6 and IL-8. The activated CAFs could promote OS cell invasion and migration by mediating TGF-β/COL6A1 signaling pathway. Conclusion: Our data demonstrated that upregulation of COL6A1 activated by H3K27 acetylation promoted the cell migration and invasion by suppressing STAT1 pathway in OS cells. Moreover, COL6A1 can be packaged into OS cell-derived exosomes and activate CAFs to promote OS metastasis.

Intrafamilial Phenotypic Variability of Collagen VI-Related Myopathy Due to a New Mutation in the COL6A1 Gene

A family of five male siblings (three survivors at 48, 53 and 58 years old; two deceased at 8 months old and 2.5 years old) demonstrating significant phenotypic variability ranging from intermediate to the myosclerotic like Bethlem myopathy is presented. Whole-exome sequencing (WES) identified a new homozygous missense mutation chr21:47402679 T > C in the canonical splice donor site of the second intron (c.227 + 2T>C) in the COL6A1 gene. mRNA analysis confirmed skipping of exon 2 encoding 925 amino-acids in 94–95% of resulting transcripts. Three sibs presented with intermediate phenotype of collagen VI-related dystrophies (48, 53 and 2.5 years old) while the fourth sibling (58 years old) was classified as Bethlem myopathy with spine rigidity. The two older siblings with the moderate progressive phenotype (48 and 53 years old) lost their ability to maintain a vertical posture caused by pronounced contractures of large joints, but continued to ambulate throughout life on fully bent legs without auxiliary means of support. Immunofluorescence analysis of dermal fibroblasts demonstrated that no type VI collagen was secreted in any of the siblings’ cells, regardless of clinical manifestations severity while fibroblast proliferation and colony formation ability was decreased. The detailed genetic and long term clinical data contribute to broadening the genotypic and phenotypic spectrum of COL6A1 related disease.

The impact of COL1A1 and COL6A1 expression on hypospadias and penile curvature severity

BACKGROUND

Hypospadias, the most frequent congenital male external genitalia abnormality, is usually associated with curvature of the ventral penis, i.e. chordee. Abnormality of darto tissue has been suggested as the pathophysiology of chordees. Collagen is one of the most abundant fibrous proteins within the extracellular matrix. In this study, we determined the expression of collagen 1 (COL1A1) and COL6A1 in patients with hypospadias and associated them with the severity of penile curvature.

METHODS

We included 60 children < 18 years old, consisting of 20 distal hypospadias, 20 proximal hypospadias patients, and 20 controls in our institution from 2017 - 2020. The expression of COL1A1 and COL6A1 in darto tissue was determined by reverse-transcriptase polymerase chain reaction (qPCR). The penile curvature severity was classified as mild (< 30 degrees), moderate (30-60 degrees), and severe (> 60 degrees).

RESULTS

qPCR showed that COL1A1 and COL6A1 expression was significantly downregulated in the distal (0.88 (0.38-2.53) and 0.54 (0.16-4.35), respectively) and proximal 0.76 (0.33-2.57) and 0.57 (0.18-1.38), respectively) hypospadias groups compared to controls (1.85 (0.24-4.61) and 0.93 (0.17-4.06), respectively) with p-values of 0.024 and 0.018, respectively. Furthermore, there was a moderate correlation between COL1A1 and COL6A1 expression (r = 0.458, p < 0.0001). Interestingly, COL1A1 and COL6A1 were also significantly downregulated in the moderate and severe chordee groups compared to the mild chordee groups, with p-values of 0.003 and 0.037, respectively.

CONCLUSIONS

Aberrant COL1A1 and COL6A1 expression might affect abnormalities in darto tissue and penile curvature severity in hypospadias patients.

Congenital muscular dystrophy-associated inflammatory chemokines provide axes for effective recruitment of therapeutic adult stem cell into muscles

Background

Congenital muscular dystrophies (CMD) are a clinically and genetically heterogeneous group of neuromuscular disorders characterized by muscle weakness. The two most prevalent forms of CMD, collagen VI-related myopathies (COL6RM) and laminin α2 deficient CMD type 1A (MDC1A), are both caused by deficiency or dysfunction of extracellular matrix proteins. Previously, we showed that an intramuscular transplantation of human adipose-derived stem cells (ADSC) into the muscle of the Col6a1^−/− mice results in efficient stem cell engraftment, migration, long-term survival, and continuous production of the collagen VI protein, suggesting the feasibility of the systemic cellular therapy for COL6RM. In order for this therapeutic approach to work however, stem cells must be efficiently targeted to the entire body musculature. Thus, the main goal of this study is to test whether muscle homing of systemically transplanted ADSC can be enhanced by employing muscle-specific chemotactic signals originating from CMD-affected muscle tissue.

Methods

Proteomic screens of chemotactic molecules were conducted in the skeletal muscles of COL6RM- and MDC1A-affected patients and CMD mouse models to define the inflammatory and immune activities, thus, providing potential markers of disease activity or treatment effect. Also using a pre-clinical animal model, recapitulating mild Ullrich congenital muscular dystrophy (UCMD), the therapeutic relevance of identified chemotactic pathways was investigated in vivo, providing a basis for future clinical investigations.

Results

Comprehensive proteomic screens evaluating relevant human and mouse skeletal muscle biopsies offered chemotactic axes to enhance directional migration of systemically transplanted cells into CMD-affected muscles, including CCL5-CCR1/3/5, CCL2-CCR2, CXCL1/2-CXCR1,2, and CXCL7-CXCR2. Also, the specific populations of ADSC selected with an affinity for the chemokines being released by damaged muscle showed efficient migration to injured site and presented their therapeutic effect.

Conclusions

Collectively, identified molecules provided insight into the mechanisms governing directional migration and intramuscular trafficking of systemically infused stem cells, thus, permitting broad and effective application of the therapeutic adult stem cells for CMD treatment.

The Landscape of DNA Methylation Associated With the Transcriptomic Network of Intramuscular Adipocytes Generates Insight Into Intramuscular Fat Deposition in Chicken

Intramuscular fat (IMF), which regulated by genetics, nutrition and environment is an important factor that influencing meat quality. Up to now, the epigenetic regulation mechanism underlying poultry IMF deposition remains poorly understood. Here, we focused on the DNA methylation, which usually regulate genes in transcription level. To look into the essential role of DNA methylation on the IMF deposition, chicken intramuscular preadipocytes were isolated and cultured in vitro, and a model of intramuscular adipocyte differentiation was constructed. Combined the whole genome bisulfite sequencing (WGBS) and RNA-Seq technologies, we identified several methylated genes, which mainly affecting fatty acid metabolism and muscle development. Furthermore, we reported that DNA methylation regulate intramuscular adipogenesis by regulating the genes, such as collagen, type VI, alpha 1 (COL6A1) thus affecting IMF deposition. Overexpression of COL6A1 increases the lipid droplet and inhibits cell proliferation by regulating CHAD and CAMK2 in intramuscular adipocytes, while knockdown of COL6A1 shows the opposite effect. Taken together, our results reveal that DNA methylation plays an important role in poultry IMF deposition.

A new single nucleotide polymorphism affects the predisposition to thoracic ossification of the posterior longitudinal ligament

Background

Thoracic ossification of the posterior longitudinal ligament (T-OPLL) is one of the common factors that cause thoracic spinal stenosis, which results in intractable myelopathy and radiculopathy. Our previous study first reported rs201153092A site mutation in the collagen 6A1 (COL6A1) gene as a potentially pathogenic locus for T-OPLL. We aimed to determine whether the rs201153092A site mutation causes abnormal expression of the COL6A1 in Han Chinese patients with T-OPLL and whether this locus is also associated with cervical-OPLL.

Methods

Peripheral blood was collected from a total of 60 patients with T-OPLL disease (30 patients carrying the rs201153092A site mutation in COL6A1 and 30 wild-type patients) and 400 northern Chinese individuals (200 cervical-OPLL patients and 200 control subjects) using the Sequenom system. The expression of COL6A1 was analyzed by enzyme-linked immunosorbent assay, reverse transcription-quantitative polymerase chain reaction, and Western blotting.

Results

rs201153092A mutation resulted in markedly increased COL6A1 gene expression levels in peripheral blood samples. The allele frequency and genotype frequency results showed that this locus is no difference between cervical-OPLL patients and controls.

Conclusions

The rs201153092A site mutation of COL6A1 can significantly increase the expression of COL6A1. The COL6A1 gene rs201153092A site polymorphism is a potential pathogenic mutation in T-OPLL disease, which may be only associated with the occurrence of T-OPLL.

Collagen VI-related myopathy: Expanding the clinical and genetic spectrum

INTRODUCTION

We aimed to analyze the clinical and genetic characteristics of collagen VI-related myopathy.

METHODS

We analyzed the clinical course and mutation spectrum in patients with collagen VI gene mutations among our congenital muscular dystrophy cohort.

RESULTS

Among 24 patients with mutations in collagen VI coding genes, 13 (54.2%) were categorized as Ullrich type, and 11 (45.8%) as non-Ullrich type. Congenital orthopedic problems were similarly observed in both types, yet multiple joint contractures were found only in the Ullrich type. Clinical courses and pathology findings varied between patients. Mutations in COL6A1, COL6A2, and COL6A3 were found in 15 (65%), 3 (13%), and 5 (22%) patients, respectively, without genotype-phenotype association. Five novel variants were detected.

DISCUSSION

We verified clinical heterogeneity of collagen VI-related myopathy, which emphasizes the importance of genetic testing. Genotype-phenotype association or early predictors for progression were not identified. Multiple joint contractures predict rapid deterioration. Muscle Nerve 58: 381-388, 2018.

COL6A1 mutation leading to Bethlem myopathy with recurrent hematuria: a case report

Background

Collagen VI-related myopathies are a spectrum of muscular diseases with features of muscle weakness and atrophy, multiple contractures of joints, distal hyperextensibility, severe respiratory dysfunction and cutaneous alterations, attributable to mutations in the COL6A1, COL6A2, and COL6A3 genes. However, no case of collagen VI mutations with hematuria has been reported. We report a 14-year-old boy who had both Bethlem myopathy and recurrent hematuria and who carried a known de novo COL6A1 missense mutation c.877G > A (p.G293R).

Case presentation

The patient was a 14-year-old boy presenting with muscle weakness from 3 years of age without any family history. Six months before admission, he developed recurrent gross hematuria, three bouts in total, with the presence of blood clots in the urine. Next-generation sequencing of his whole-exome was performed. The result of sequencing revealed a de novo heterozygous G-to-A nucleotide substitution at position 877 in exon 10 of the COL6A1 gene. After treatment, the hematuria healed, but the muscle weakness failed to improve.

Conclusions

Hematuria in Bethlem myopathy can be caused by COL6 mutations, which may be related to the aberrant connection between collagen VI and collagen IV.

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1263-0) contains supplementary material, which is available to authorized users.

A novel de novo COL6A1 mutation emphasizes the role of intron 14 donor splice site defects as a cause of moderate-progressive form of ColVI myopathy - a case report and review of the genotype-phenotype correlation

Collagen VI-related myopathy is a group of disorders affecting skeletal muscles and connective tissue. The most common symptoms are muscle weakness and joint deformities which limit the movement and progress over time. Several forms of collagen VI-related myopathies have been described: Bethlem myopathy, an intermediate form and Ullrich congenital muscular dystrophy, which is the most severe. Here we report a novel de novo c.1056+3A>C substitution in intron 14 of the COL6A1 gene encoding alpha-chains of collagen VI in a 13-year-old girl suffering from collagen VI (ColVI) myopathy. Analysis performed on cDNA generated from the RNA obtained from the patient's blood cells showed that the reported variant leads to the entire exon 14 skipping and probably results in an in-frame deletion of 18 amino acids of the COL6A1 protein. Clinical presentation, abnormal secretion of the collagen demonstrated in muscle biopsy and the COL6A1 c.1056+3A>C mutation justify classification of the presented case as ColVI myopathy with moderate-progressive course. Analysis of the literature indicates that the donor splice site of COL6A1 intron 14, associated with the phenotype of Bethlem myopathy or intermediate form, is a hot spot for ColVI myopathies.

Association of IL17RC and COL6A1 genetic polymorphisms with susceptibility to ossification of the thoracic posterior longitudinal ligament in Chinese patients

Background

In our previous whole-genome sequencing study of 30 unrelated northern Chinese Han patients, we identified six single nucleotide polymorphisms (SNPs) in the interleukin 17 receptor C (IL17RC) and collagen type VI α1 chain (COL6A1) genes that were potentially associated with thoracic ossification of the posterior longitudinal ligament (T-OPLL). To determine whether these six SNPs are associated with susceptibility to T-OPLL in the northern Chinese Han population, we performed a case-control association study to confirm specific susceptible loci in the expanded samples.

Methods

The six SNPs in the IL17RC and COL6A1 genes were analyzed in 200 northern Chinese individuals (100 patients and 100 control subjects) using the Sequenom system.

Results

The genotype distributions and allele frequencies of each SNP in the control and patient groups were compared. rs201153092, rs13051496, rs199772854, rs76999397, and rs189013166 showed potential pathogenic loci for T-OPLL in the northern Chinese Han population, whereas rs151158105 did not. At the genotype level, the differences in the genotype frequencies of rs201153092, rs13051496, rs199772854, rs76999397, and rs189013166 between T-OPLL cases and controls reached statistical significance.

Conclusions

To the best of our knowledge, this is the first association study of susceptibility genes in Han Chinese patients with T-OPLL. The results revealed five SNPs in the IL17RC and COL6A1 genes that represented potentially pathogenic mutations in patients with T-OPLL.

Genetic and clinical findings in a Chinese cohort of patients with collagen VI-related myopathies

Collagen VI-related myopathy, caused by pathogenic variants in the genes encoding collagen VI, represents a clinical continuum from Ullrich congenital muscular dystrophy (UCMD) to Bethlem myopathy (BM). Clinical data of 60 probands and their family members were collected and muscle biopsies of 26 patients were analyzed. COL6A1, COL6A2 and COL6A3 exons were analyzed by direct sequencing or next generation sequencing (NGS). Sixty patients were characterized by delayed motor milestones, muscle weakness, skin and joint changes with 40 UCMD and 20 BM. Muscle with biopsies revealed dystrophic changes and showed completely deficiency of collagen VI or sarcolemma specific collagen VI deficiency. We identified 62 different pathogenic variants in these 60 patients, with 34 were first reported while 28 were previously known; 72 allelic pathogenic variants in COL6A1 (25/72, 34.7%), COL6A2 (33/72, 45.8%) and COL6A3 (14/72, 19.4%). We also found somatic mosaic variant in the parent of 1 proband by personal genome machine amplicon deep sequencing for mosaicism. Here we provide clinical, histological and genetic evidence of collagen VI-related myopathy in 60 Chinese patients. NGS is a valuable approach for diagnosis and accurate diagnosis provides useful information for genetic counseling of related families.

Upregulation of COL6A1 is predictive of poor prognosis in clear cell renal cell carcinoma patients

BACKGROUND

The extracellular matrix (ECM) is reported to play an important role in tumorigenesis and progression. Collagen VI is an important ECM protein. In this study, we investigated the potential role of the COL6A1 gene, which encodes the α1 polypeptide of collagen VI, in the biological functions involved in the progression and outcome of clear cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

A total of 288 ccRCC patients who underwent radical nephrectomy (RN) or nephron sparing nephrectomy (NSS) at Fudan University Shanghai Cancer Center (FUSCC) were enrolled. Total RNA was extracted from frozen samples obtained from the tissue bank of FUSCC and expression of COL6A1 was determined by qRT-PCR. The clinical relationship between COL6A1 expression and ccRCC prognosis was analyzed. These data were then validated in the Cancer Genome Atlas (TCGA) cohort. We also investigated the effect of COL6A1 overexpression in a xenografted tumor model in nude mice in vivo.

RESULTS

In multivariate analysis of TCGA cohorts, COL6A1 high expression was predictive of poor prognosis in ccRCC patients' overall survival (OS) (HR: 2.588 95%CI 1.616-4.146) and disease free survival(DFS) (HR: 3.106 95%CI 1.534-6.288). In FUSCC cohorts, after adjusted for relevant factors, the COL6A1 expression indicates poor prognosis in ccRCC patients's OS (HR 2.211; 95% CI, 1.360-8.060) and DFS (HR 3.052; 95%CI, 1.500-6.210). COL6A1 overexpression promoted tumor growth in xenografted nude mice.

CONCLUSION

Increased COL6A1 expression correlates with poor prognosis in ccRCC patients. Moreover, COL6A1 stimulates tumor growth in vivo.

Expression of COL6A1 predicts prognosis in cervical cancer patients

COL6A1 has been shown to play an important role in tumor initiation and progression. The present study is to investigate the clinical significance of COL6A1 in cervical cancer. In this study, the COL6A1 expression levels in 10 paired cervical cancer tissues and the adjacent non-tumor tissues were examined by real-time PCR. The expression of COL6A1 protein was examined in 162 cervical cancer samples by immunohistochemistry, and the correlation of COL6A1 expression with clinicopathologic factors was analyzed. The overall and recurrent-free survival rates were estimated using Kaplan-Meier method and compared with the log-rank test. The prognostic analysis was carried out with multivariate Cox regressions model. The result showed that COL6A1 expression was up-regulated in cervical cancer tissues in compared with that in non-tumor tissues. High expression of COL6A1 was significantly correlated with FIGO stage (P<0.001), tumor size (P=0.025) and lymph node metastasis (P=0.028) of the disease. Moreover, survival analysis showed that high expression of COL6A1 was significantly associated with poorer overall (OS) and recurrent free (RFS) survival (p=0.004 and =0.001, respectively) of cervical cancer patients. Multivariate analysis suggested that COL6A1 expression was an independent prognostic marker of cervical cancer (P=0.029). Thus, COL6A1 may serve as an oncogene in the initiation and progression of cervical cancer, and as a predictor of poor prognosis in cervical cancer patients.

Reactive stroma component COL6A1 is upregulated in castration-resistant prostate cancer and promotes tumor growth

Castration-resistant prostate cancer (CRPC) remains the most critical challenge in the clinical management of prostate cancer (PCa). Reactive stromal changes in PCa are likely involved in the emergence of CRPC. In the present study, we identified a novel oncogene termed COL6A1 which was upregulated in the reactive stroma of CRPC. We established an androgen-independent LNCaP (LNCaP-AI) cell line in steroid-reduced (SR) medium within 2 months. We examined COL6A1 expression with western blot during the LNCaP-AI induction, and studied the function of COL6A1 in vitro and in vivo. Immunohistochemical staining of COL6A1 was performed in ten pairs of androgen-sensitive PCa and CRPC samples. We demonstrated that COL6A1 expression was markedly increased in LNCaP-AI cells and CRPC tissues compared with LNCaP cells and paired androgen-sensitive PCa specimens. In vitro, COL6A1 knockdown resulted in G1-S cell cycle arrest and descended vitality. Overexpression of COL6A1 was associated with accelerated S phase entry and elevated vitality in prostate cancer cells. COL6A1 also promoted tumorigenesis of LNCaP cells in vivo. Taken together, these data suggest an important role of COL6A1 in the molecular etiology of castration-resistant prostate cancer, and support the potential use of COL6A1 in CRPC therapy.

Mosaicism for dominant collagen 6 mutations as a cause for intrafamilial phenotypic variability

Collagen 6-related dystrophies and myopathies (COL6-RD) are a group of disorders that form a wide phenotypic spectrum, ranging from severe Ullrich congenital muscular dystrophy, intermediate phenotypes, to the milder Bethlem myopathy. Both inter- and intrafamilial variable expressivity are commonly observed. We present clinical, immunohistochemical, and genetic data on four COL6-RD families with marked intergenerational phenotypic heterogeneity. This variable expression seemingly masquerades as anticipation is due to parental mosaicism for a dominant mutation, with subsequent full inheritance and penetrance of the mutation in the heterozygous offspring. We also present an additional fifth simplex patient identified as a mosaic carrier. Parental mosaicism was confirmed in the four families through quantitative analysis of the ratio of mutant versus wild-type allele (COL6A1, COL6A2, and COL6A3) in genomic DNA from various tissues, including blood, dermal fibroblasts, and saliva. Consistent with somatic mosaicism, parental samples had lower ratios of mutant versus wild-type allele compared with the fully heterozygote offspring. However, there was notable variability of the mutant allele levels between tissues tested, ranging from 16% (saliva) to 43% (fibroblasts) in one mosaic father. This is the first report demonstrating mosaicism as a cause of intrafamilial/intergenerational variability of COL6-RD, and suggests that sporadic and parental mosaicism may be more common than previously suspected.

Ullrich Congenital Muscular Dystrophy (UCMD): Clinical and Genetic Correlations

OBJECTIVE

Ullrich congenital muscular dystrophy (UCMD) corresponds to the severe end of the clinical spectrum of neuromuscular disorders caused by mutations in the genes encoding collagen VI (COL VI). We studied four unrelated families with six affected children that had typical UCMD with dominant and recessive inheritance.

MATERIALS & METHODS

Four unrelated Iranian families with six affected children with typical UCMD were analyzed for COLVI secretion in skin fibroblast culture and the secretion of COLVI in skin fibroblast culture using quantitative RT-PCR (Q-RT-PCR), and mutation identification was performed by sequencing of complementary DNA.

RESULTS

COL VI secretion was altered in all studied fibroblast cultures. Two affected sibs carried a homozygous nonsense mutation in exon 12 of COL6A2, while another patient had a large heterozygous deletion in exon 5-8 of COL6A2. The two other affected sibs had homozygote mutation in exon 24 of COL6A2, and the last one was homozygote in COL6A1.

CONCLUSION

In this study, we found out variability in clinical findings and genetic inheritance among UCMD patients, so that the patient with complete absence of COLVI was severely affected and had a large heterozygous deletion in COL6A2. In contrast, the patients with homozygous deletion had mild to moderate decrease in the secretion of COL VI and were mildly to moderately affected.