Post-translational modifications of vimentin reflect different pathological processes associated with non-small cell lung cancer and chronic obstructive pulmonary disease

Hot and cold fibrosis: The role of serum biomarkers to assess immune mechanisms and ECM-cell interactions in human fibrosis

Fibrosis is a pathological condition characterised by excessive accumulation of extracellular matrix (ECM) components, particularly collagens, leading to tissue scarring and organ dysfunction. In fibrosis, an imbalance between collagen synthesis (fibrogenesis) and degradation (fibrolysis) results in the deposition of fibrillar collagens disrupting the structural integrity of the ECM and, consequently, tissue architecture. Fibrosis is associated with a wide range of chronic diseases, including cirrhosis, kidney fibrosis, pulmonary fibrosis, and autoimmune diseases. Recently, the concept of "hot" and "cold" fibrosis has emerged, referring to the immune status within fibrotic tissues and the nature of fibrogenic signalling. Hot fibrosis is characterised by active immune cell infiltration and inflammation, while cold fibrosis is associated with auto- and paracrine myofibroblast activation, immune cell exclusion and quiescence. In this article, we explore the relationship between hot and cold fibrosis, the role of various types of collagens and their biologically active fragments in modulating the immune system, and how serological ECM biomarkers can help improve our understanding of the disease-relevant interactions between immune and mesenchymal cells in fibrotic tissues. Additionally, we draw lessons from immuno-oncology research in solid tumours to shed light on potential strategies for fibrosis treatment and highlight the advantage of having a "hot fibrotic environment" to treat fibrosis by enhancing collagen degradation through modulation of the immune system.

Identification of Novel Biomarkers for Ischemic Stroke Through Integrated Bioinformatics Analysis and Machine Learning

Ischemic stroke leads to permanent damage to the affected brain tissue, with strict time constraints for effective treatment. Predictive biomarkers demonstrate great potential in the clinical diagnosis of ischemic stroke, significantly enhancing the accuracy of early identification, thereby enabling clinicians to intervene promptly and reduce patient disability and mortality rates. Furthermore, the application of predictive biomarkers facilitates the development of personalized treatment plans tailored to the specific conditions of individual patients, optimizing treatment outcomes and improving prognoses. Bioinformatics technologies based on high-throughput data provide a crucial foundation for comprehensively understanding the biological characteristics of ischemic stroke and discovering effective predictive targets. In this study, we evaluated gene expression data from ischemic stroke patients retrieved from the Gene Expression Omnibus (GEO) database, conducting differential expression analysis and functional analysis. Through weighted gene co-expression network analysis (WGCNA), we characterized gene modules associated with ischemic stroke. To screen candidate core genes, three machine learning algorithms were applied, including Least Absolute Shrinkage and Selection Operator (LASSO), random forest (RF), and support vector machine-recursive feature elimination (SVM-RFE), ultimately identifying five candidate core genes: MBOAT2, CKAP4, FAF1, CLEC4D, and VIM. Subsequent validation was performed using an external dataset. Additionally, the immune infiltration landscape of ischemic stroke was mapped using the CIBERSORT method, investigating the relationship between candidate core genes and immune cells in the pathogenesis of ischemic stroke, as well as the key pathways associated with the core genes. Finally, the key gene VIM was further identified and preliminarily validated through four machine learning algorithms, including generalized linear model (GLM), Extreme Gradient Boosting (XGBoost), RF, and SVM-RFE. This study contributes to advancing our understanding of biomarkers for ischemic stroke and provides a reference for the prediction and diagnosis of ischemic stroke.

Characterization of lung function impairment and pathological changes induced by chronic lead and cadmium inhalation: Insights from a mouse model study

Exposure to environmental heavy metals such as lead (Pb) and cadmium (Cd) is a global concern due to their widespread presence. However, the specific pulmonary effects of inhaled exposure, especially related to long-term effects, remain poorly understood. In this study, we developed a novel mouse model of Pb and Cd inhalation to mimic real-world conditions and investigate pulmonary effects. Mice were exposed to Pb and Cd inhalation for 6 months using a whole-body exposure system, resulting in decreased lung compliance and progression from emphysematous changes to fibrosis. In addition, the blood Pb/Cd levels of mice exposed to Pb/Cd for 6 months are like those of humans occupationally exposed to heavy metals. Histology revealed inflammation and collagen deposition. Transcriptomic analysis highlighted immune responses and macrophage activity in developing fibrosis. These results confirm an association between Pb/Cd exposure and emphysema and fibrosis, reflecting clinical findings. The study highlights the importance of long-term exposure assessment and time-course analysis for understanding Pb/Cd-induced lung disease. The relevance of the mouse model in replicating human exposure scenarios underscores its value in studying fibrosis and emphysema simultaneously. These findings provide a basis for targeted therapeutic interventions against heavy metal-induced lung injury.

Citrullinated and MMP-degraded vimentin is associated with chronic pulmonary diseases and genetic variants in PADI3/PADI4 and CFH in postmenopausal women

Citrullinated vimentin has been linked to several chronic and autoimmune diseases, but how citrullinated vimentin is associated with disease prevalence and genetic variants in a clinical setting remains unknown. The aim of this study was to obtain a better understanding of the genetic variants and pathologies associated with citrullinated and MMP-degraded vimentin. Patient Registry data, serum samples and genotypes were collected for a total of 4369 Danish post-menopausal women enrolled in the Prospective Epidemiologic and Risk Factor study (PERF). Circulating citrullinated and MMP-degraded vimentin (VICM) was measured. Genome-wide association studies (GWAS) and phenome wide association studies (PheWAS) with levels of VICM were performed. High levels of VICM were significantly associated with the prevalence of chronic pulmonary diseases and death from respiratory and cardiovascular diseases (CVD). GWAS identified 33 single nucleotide polymorphisms (SNPs) with a significant association with VICM. These variants were in the peptidylarginine deiminase 3/4 (PADI3/PADI4) and Complement Factor H (CFH)/KCNT2 gene loci on chromosome 1. Serum levels of VICM, a marker of citrullinated and MMP-degraded vimentin, were associated with chronic pulmonary diseases and genetic variance in PADI3/PADI4 and CFH/ KCNT2. This points to the potential for VICM to be used as an activity marker of both citrullination and inflammation, identifying responders to targeted treatment and patients likely to experience disease progression.

Vimentin takes a hike - Emerging roles of extracellular vimentin in cancer and wound healing

Vimentin is a cytoskeletal protein important for many cellular processes, including proliferation, migration, invasion, stress resistance, signaling, and many more. The vimentin-deficient mouse has revealed many of these functions as it has numerous severe phenotypes, many of which are found only following a suitable challenge or stress. While these functions are usually related to vimentin as a major intracellular protein, vimentin is also emerging as an extracellular protein, exposed at the cell surface in an oligomeric form or secreted to the extracellular environment in soluble and vesicle-bound forms. Thus, this review explores the roles of the extracellular pool of vimentin (eVIM), identified in both normal and pathological states. It focuses specifically on the recent advances regarding the role of eVIM in wound healing and cancer. Finally, it discusses new technologies and future perspectives for the clinical application of eVIM.

Extracellular matrix remodeling proteins as biomarkers for clinical assessment and treatment outcomes in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic progressive inflammatory disease of the esophagus, characterized by extracellular matrix remodeling and fibrotic stricture formation. Disease monitoring requires multiple re-endoscopies with esophageal biopsies. Hence non-invasive methods for determining tissue fibrosis and treatment efficacy are warranted.

AIMS

To investigate the ability of extracellular matrix proteins in serum as potential biomarkers of tissue remodeling and clinical, endoscopic, and histological disease outcomes in adult EoE patients.

METHODS

Protein-fingerprint assays were used to measure neo-epitope specific fragments of collagen remodeling, human-neutrophil elastase degraded calprotectin, and citrullinated or non-citrullinated vimentin in the serum of an adult EoE-cohort. Biomarker analysis, symptoms, endoscopic features and histological disease activity (eosinophils(eos) per high-power-field(hpf)) were evaluated at baseline and after six weeks of dietary intervention.

RESULTS

Patients with a baseline (Endoscopic Reference score) EREFS fibrosis subscore ≥ 2 presented with increased fibrolysis of cross-linked type III collagen (CTX-III) (p < 0.01), whereas low CTX-III levels were observed in patients achieving histological remission (< 15 eos/hpf) (vs. no histological remission (p < 0.05). Progression of endoscopic fibrosis after intervention was associated with increased levels of type-III (PRO-C3) and -VI collagen (PRO-C6) formation (all; p < 0.05). A baseline EREFS inflammatory subscore ≥ 2 correlated with higher neutrophilic activity (Cpa9-HNE) at week 6 (p < 0.05). Moreover, increased degradation of type-III (C3M) and -IV (C4M/PRO-C4) collagens were associated with remission of food impaction after intervention (all; p < 0.05).

CONCLUSION

Serum extracellular matrix remodeling proteins demonstrated potential as surrogate biomarkers for assessing histological disease remission, endoscopic fibrosis, and remission of symptoms of food impaction after diet intervention in adult EoE patients.

Preliminary investigation of elevated collagen and blood-clotting markers as potential noninvasive biomarkers for small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is highly aggressive with limited therapeutic options and a poor prognosis. Moreover, noninvasive biomarker tools for detecting disease and monitoring treatment response are lacking. To address this, we evaluated serum biomarkers of extracellular matrix proteins not previously explored in SCLC.

METHODS

We measured biomarkers in the serum of 16 patients with SCLC before and after chemotherapy as well as in the serum of 11 healthy individuals.

RESULTS

Our findings demonstrated that SCLC serum had higher levels of collagen type I degradation, collagen type III formation, and collagen type XI formation than healthy controls. In addition, we observed higher levels of type XIX and XXII collagens, fibrinogen, and von Willebrand factor A formation in SCLC serum. The formation of type I collagen did not exhibit any discernible variation. However, we observed a decrease in the degradation of type I collagen following chemotherapy.

CONCLUSION

Overall, our findings revealed elevated levels of collagen and blood-clotting markers in the serum of SCLC patients, indicating the potential of ECM proteins as noninvasive biomarkers for SCLC.

Revisiting Circulating Extracellular Matrix Fragments as Disease Markers in Myelofibrosis and Related Neoplasms

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.

In Contrast to Anti-CCP, MMP-Degraded and Citrullinated Vimentin (VICM) Is Both a Diagnostic and a Treatment Response Biomarker

Protein citrullination and degradation by matrix metalloproteinases (MMP) plays a central role in the pathology of rheumatoid arthritis (RA). Autoantibodies are known to target citrullinated vimentin. The aim of this study was to investigate the relationship between the blood levels of MMP-degraded and citrullinated vimentin (VICM), as compared with the levels of MMP-degraded and non-citrullinated vimentin (VIM), and the standard anti-CCP biomarker in RA patients undergoing treatment. Thus, VIM, VICM and anti-CCP were quantified by ELISA in serum samples from baseline and week 8 of patients (n = 257) with RA, treated with either tocilizumab (8 mg/kg), methotrexate (7.5−15 mg/kg) or a placebo and compared with a reference cohort (n = 64). The three biomarkers were elevated in RA serum compared with the reference cohort: medians were 1.7 vs. 0.8 ng/mL (p < 0.05) for VIM; 7.5 vs. 0.7 ng/mL (p < 0.0001) for VICM; 57 vs. 4 RU/mL (p < 0.001) for anti-CCP. VICM was decreased in response to tocilizumab (2.9-fold, p < 0.0001) and to methotrexate (1.5-fold, p < 0.05) compared with the placebo, while anti-CCP was not. Serum VIM was also modulated by both drugs, although to a lesser degree. A high baseline level of VICM was predictive of a low disease activity response at week 8. In conclusion, VICM can differentiate between RA and healthy donors in a similar manner to anti-CCP; furthermore, VICM is also a pharmacodynamic marker.

Pathophysiological Role of Vimentin Intermediate Filaments in Lung Diseases

Vimentin intermediate filaments, a type III intermediate filament, are among the most widely studied IFs and are found abundantly in mesenchymal cells. Vimentin intermediate filaments localize primarily in the cytoplasm but can also be found on the cell surface and extracellular space. The cytoplasmic vimentin is well-recognized for its role in providing mechanical strength and regulating cell migration, adhesion, and division. The post-translationally modified forms of Vimentin intermediate filaments have several implications in host-pathogen interactions, cancers, and non-malignant lung diseases. This review will analyze the role of vimentin beyond just the epithelial to mesenchymal transition (EMT) marker highlighting its role as a regulator of host-pathogen interactions and signaling pathways for the pathophysiology of various lung diseases. In addition, we will also examine the clinically relevant anti-vimentin compounds and antibodies that could potentially interfere with the pathogenic role of Vimentin intermediate filaments in lung disease.

Considerations for understanding protein measurements: Identification of formation, degradation and more pathological relevant epitopes

OBJECTIVES

There is a need for precision medicine and an unspoken promise of an optimal approach for identification of the right patients for value-based medicine based on big data. However, there may be a misconception that measurement of proteins is more valuable than measurement of fewer selected biomarkers. In population-based research, variation may be somewhat eliminated by quantity. However, this fascination of numbers may limit the attention to and understanding of the single. This review highlights that protein measurements (with collagens as examples) may mean different things depending on the targeted epitope - formation or degradation of tissues, and even signaling potential of proteins.

DESIGN AND METHODS

PubMed was searched for collagen, neo-epitope, biomarkers.

RESULTS

Ample examples of assays with specific epitopes, either pathological such as HbA1c, or domain specific such as pro-peptides, which total protein arrays would not have identified were evident.

CONCLUSIONS

We suggest that big data may be considered as the funnel of data points, in which most important parameters will be selected. If the technical precision is low or the biological accuracy is limited, and we include suboptimal quality of biomarkers, disguised as big data, we may not be able to fulfill the promise of helping patients searching for the optimal treatment. Alternatively, if the technical precision of the total protein quantification is high, but we miss the functional domains with the most considerable biological meaning, we miss the most important and valuable information of a given protein. This review highlights that measurements of the same protein in different ways may provide completely different meanings. We need to understand the pathological importance of each epitope quantified to maximize protein measurements.

Noninvasive prognostic biomarker potential of quantifying the propeptides of Type XI collagen alpha-1 chain (PRO-C11) in patients with pancreatic ductal adenocarcinoma

Type XI collagen has been associated with tumor fibrosis and aggressiveness in patients with pancreatic ductal adenocarcinoma (PDAC). The propeptide on Type XI collagen is released into the circulation after proteolytic processing at either amino acid 253 or 511. This allows for a noninvasive biomarker approach to quantify Type XI collagen production. We developed two ELISA-based biomarkers, targeting the two enzymatic cleavage sites (PRO-C11-253 and PRO-C11-511). In a discovery cohort including serum from patients with PDAC (n = 39, Stages 1-4), chronic pancreatitis (CP, n = 12) and healthy controls (n = 20), PRO-C11-511, but not PRO-C11-253, was significantly upregulated in patients with PDAC and CP compared to healthy controls. Furthermore, PRO-C11-511 levels >75th percentile were associated with poor overall survival (OS) (HR, 95% CI: 3.40, 1.48-7.83). The PRO-C11-511 biomarker potential was validated in serum from 686 patients with PDAC. Again, high levels of PRO-C11-511 (>75th percentile) were associated with poor OS (HR, 95% CI: 1.68, 1.40-2.02). Furthermore, PRO-C11-511 remained significant after adjusting for clinical risk factors (HR, 95% CI: 1.50, 1.22-1.86). In conclusion, quantifying serum levels of Type XI collagen with PRO-C11-511 predicts poor OS in patients with PDAC. This supports that Type XI collagen is important for PDAC biology and that PRO-C11-511 has prognostic noninvasive biomarker potential for patients with PDAC.

Circulating Vimentin Is Associated With Future Incidence of Stroke in a Population-Based Cohort Study

BACKGROUND AND PURPOSE

VIM (vimentin) is a cytoskeletal intermediate filament protein, which has been linked to atherosclerosis and thrombosis; both are important causes of stroke. We examined the relationship between circulating VIM and incidence of stroke, and if carotid plaque could modify the association in a prospective population-based cohort.

METHODS

This prospective study was based on the Malmö Diet and Cancer Cohort. A total of 4688 participants (39.7% men; mean age, 57.6 years) were examined and blood samples were collected between 1991 and 1994. Incidence of stroke was followed up to 2018. Cox' proportional hazards regression was used to assess the relationship between VIM and stroke.

RESULTS

During a mean follow-up of 22.0 years, a total of 528 subjects were diagnosed with stroke, among which 434 were ischemic stroke. Participants in the highest quartile (vs 1^st quartile) had 1.34× higher risk of total stroke (95% CI, 1.03-1.74) and 1.47× higher of ischemic stroke (95% CI, 1.10-1.98) after adjustment for potential confounders. A significant interaction was found between carotid plaque and VIM with respect to incidence of both total stroke and ischemic stroke (P=0.041 and 0.011, respectively). After stratifying by carotid plaque, high VIM had stronger association with stroke in participants with carotid plaque, especially for the risk of ischemic stroke (adjusted hazard ratio,1.66 [95% CI, 1.23-2.25] for quartile 4 versus quartile 1 to 3).

CONCLUSIONS

VIM is positively associated with the incidence of stroke, especially in individuals with carotid plaque. Further studies are needed to confirm the observed associations.

Serum Type XIX Collagen is Significantly Elevated in Non-Small Cell Lung Cancer: A Preliminary Study on Biomarker Potential

Type XIX collagen is a poorly characterized collagen associated with the basement membrane. It is abnormally regulated during breast cancer progression and the NC1 (XIX) domain has anti-tumorigenic signaling properties. However, little is known about the biomarker potential of collagen XIX in cancer. In this study, we describe a competitive ELISA, named PRO-C19, targeting the C-terminus of collagen XIX using a monoclonal antibody. PRO-C19 was measured in serum of patients with a range of cancer types and was elevated in non-small cell lung cancer (NSCLC) (p < 0.0001), small cell lung cancer (p = 0.0081), breast (p = 0.0005) and ovarian cancer (p < 0.0001) compared to healthy controls. In a separate NSCLC cohort, PRO-C19 was elevated compared to controls when evaluating adenocarcinoma (AD) (p = 0.0003) and squamous cell carcinoma (SCC) (p < 0.0001) patients but was not elevated in chronic obstructive pulmonary disease patients. SCC also had higher PRO-C19 levels than AD (p = 0.0457). PRO-C19 could discriminate between NSCLC and healthy controls (AUROC:0.749 and 0.826 for AD and SCC, respectively) and maintained discriminatory performance in patients of tumor stages I+II (AUROC:0.733 and 0.818 for AD and SCC, respectively). Lastly, we confirmed the elevated type XIX collagen levels using gene expression data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) initiatives. In conclusion, type XIX collagen is released into circulation and is significantly elevated in the serum of cancer patients and PRO-C19 shows promise as a cancer biomarker.