Possible association of elevated serum collagen type IV level with skin sclerosis in systemic sclerosis

Digital ulcers associated with scleroderma: A major unmet medical need

Scleroderma or systemic sclerosis (SSc)-associated digital ischaemic complications, such as digital ulcers (SSc-DUs), appear relatively early during the disease course and are a major burden with substantial deterioration of quality of life. Expert rheumatologist and wound specialists have defined a DU; however, international application of the definition is still disorganised. Appearance of SSc-DUs is secondary to the onset of Raynaud's phenomenon and as a consequence, recommended first-line of treatment mainly includes vasodilators; however, many DUs are refractory to this treatment. Despite important practical issues, such as a lack of well-characterised SSc-wound healing animal model, significant efforts are needed to mechanistically understand the pathogenesis of SSc-DUs for developing clinically targetable disease modifying therapies.

Testing a candidate composite serum protein marker of skin severity in systemic sclerosis

Objectives

Using an integrated multi-omic analysis, we previously derived a candidate marker that estimates the modified Rodnan Skin Score (mRSS) and thus the severity of skin involvement in SSc. In the present study we explore technical and biological validation of this composite marker in a well-characterized cohort of SSc patients.

Methods

Cartilage oligomeric matrix protein (COMP), collagen type IV (COL4A1), tenascin-C (TNC) and spondin-1 (SPON1) were examined in serum samples from two independent cohorts of patients with dcSSc. The BIOlogical Phenotyping of diffuse SYstemic sclerosis cohort had previously been used to derive the composite marker and Molecular Determinants to Improve Scleroderma (SSc) treatment (MODERNISE) was a novel validation cohort. Multiple regression analysis derived a formula to predict the mRSS based on serum ELISA protein concentration.

Results

The serum concentration of two of the proteins-COMP and TNC-positively correlated with the mRSS, particularly in early dcSSc patients. Interpretable data could not be obtained for SPON1 due to technical limitations of the ELISA. COL4A1 showed a correlation with disease duration but not overall mRSS. Patients receiving MMF showed lower serum concentrations of COMP, COL4A1 and TNC and a lower composite biomarker score not established on treatment. A revised ELISA-based three-protein composite formula was derived for future validation studies.

Conclusions

Although more validation is required, our findings represent a further step towards a composite serum protein assay to assess skin severity in SSc. Future work will establish its utility as a predictive or prognostic biomarker.

Requisite instruments for the establishment of three-dimensional epidermal human skin equivalents-A methods review

Human skin equivalents (HSEs) are three-dimensional skin organ culture models raised in vitro. This review gives an overview of common techniques for setting up HSEs. The HSE consists of an artificial dermis and epidermis. 3T3-J2 murine fibroblasts, purchased human fibroblasts or freshly isolated and cultured fibroblasts, together with other components, for example, collagen type I, are used to build the scaffold. Freshly isolated and cultured keratinocytes are seeded on top. It is possible to add other cell types, for example, melanocytes, to the HSE-depending on the research question. After several days and further steps, the 3D skin can be harvested. Additionally, we show possible markers and techniques for evaluation of artificial skin. Furthermore, we provide a comparison of HSEs to human skin organ culture, a model which employs human donor skin. We outline advantages and limitations of both models and discuss future perspectives in using HSEs.

Clinical Significance of Serum Collagen Type IV and Procollagen Type III N-Peptide Levels in Diagnosis and Differential Diagnosis of Lymphedema

Background: Lymphatic endothelial cells production or modification were closely related to the extracellular matrix (ECM) molecules. The serum hyaluronic acid (HA), laminin (LN), procollagen type III N-peptide (PIIINP), and collagen type IV (CGIV) levels were researched to explore the clinical significance of serum ECM proteins in the diagnosis and differentiation of lymphedema. Methods: Fifty-five patients were enrolled. They were divided into primary lymphedema (PLE), secondary lymphedema (SLE), and venous edema (VE) groups. Twenty-two healthy controls were also recruited as normal control (NC). Serum HA, LN, PIIINP, and CGIV levels of all subjects were assessed using chemiluminescence immunoassay. Statistical analysis and receiver operating characteristic (ROC) curves were used to data analysis. Results: The serum levels of CGIV were significantly decreased in both PLE and SLE groups compared with those in the NC group. Reduced serum CGIV levels were associated with the severity of lymphedema. The serum levels of CGIV and PIIINP were identified decreased in both PLE and SLE groups compared with those in the VE group. However, the levels of serum HA and LN were not observed significantly changed in both PLE and SLE groups than those in NC or VE group. Furthermore, ROC curve indicated that serum CGIV and PIIINP were capable of providing good diagnostic and differential diagnostic efficacy at the most appropriate cutoff point value. Conclusion: The serum levels of CGIV may have clinical significance in the diagnosis of lymphedema. CGIV and PIIINP may play a role in the differentiation of lymphedema from VE.

Integrated analysis of dermal blister fluid proteomics and genome-wide skin gene expression in systemic sclerosis: an observational study

Background

Skin fibrosis is a hallmark feature of systemic sclerosis. Skin biopsy transcriptomics and blister fluid proteomics give insight into the local environment of the skin. We have integrated these modalities with the aim of developing a surrogate for the modified Rodnan skin score (mRSS), using candidate genes and proteins from the skin and blister fluid as anchors to identify key analytes in the plasma.

Methods

In this single-centre, prospective observational study at the Royal Free Campus, University College London, London, UK, transcriptional and proteomic analyses of blood and skin were performed in a cohort of patients with systemic sclerosis (n=52) and healthy controls (n=16). Weighted gene co-expression network analysis was used to explore the association of skin transcriptomics data, clinical traits, and blister fluid proteomic results. Candidate hub analytes were identified as those present in both blister and skin gene sets (modules), and which correlated with plasma (module membership >0·7 and gene significance >0·6). Hub analytes were confirmed using RNA transcript data obtained from skin biopsy samples from patients with early diffuse cutaneous systemic sclerosis at 12 months.

Findings

We identified three modules in the skin, and two in blister fluid, which correlated with a diagnosis of early diffuse cutaneous systemic sclerosis. From these modules, 11 key hub analytes were identified, present in both skin and blister fluid modules, whose transcript and protein levels correlated with plasma protein concentrations, mRSS, and showed statistically significant correlation on repeat transcriptomic samples taken at 12 months. Multivariate analysis identified four plasma analytes as correlates of mRSS (COL4A1, COMP, SPON1, and TNC), which can be used to differentiate disease subtype.

Interpretation

This unbiased approach has identified potential biological candidates that might be drivers of local skin pathogenesis in systemic sclerosis. By focusing on measurable analytes in the plasma, we generated a promising composite plasma protein biomarker that could be used for assessment of skin severity, case stratification, and as a potential outcome measure for clinical trials and practice. Once fully validated, the biomarker score could replace a clinical score such as the mRSS, which carries substantial variability.

Funding

GlaxoSmithKline and UK Medical Research Council.

Autologous hematopoietic stem cell transplantation promotes connective tissue remodeling in systemic sclerosis patients

BACKGROUND

Autologous hematopoietic stem cell transplantation (AHSCT) treats patients with severe and progressive systemic sclerosis (SSc). However, basic mechanisms associated with the therapeutic efficacy of the procedure are not entirely understood. We aimed to evaluate how AHSCT affects skin fibrosis in SSc patients.

METHODS

Clinical data, serum, and skin samples from 39 SSc patients who underwent AHSCT were retrospectively evaluated. Skin biopsies were analyzed by immunohistochemistry with anti-MMP-1, -MMP-2, -MMP-3, -MMP-9, -TIMP-1, -α-SMA, -TGF-β, and -NF-κB p65 antibodies, and stained with hematoxylin and eosin and picrosirius red to assess skin thickness and collagen density, respectively. Serum samples were evaluated by Multiplex Assay for COL1A1, COL4A1, FGF-1, MMP-1, MMP-3, MMP-12, MMP-13, PDGF-AA, PDGF-BB, S100A9, and TIMP-1 levels and compared to healthy controls.

RESULTS

After AHSCT, SSc patients showed clinical improvement in skin involvement, assessed by modified Rodnan's skin score (mRSS). Histologically, collagen density and skin thickness decreased after AHSCT. Immunohistochemical analyses showed increased expression of MMP-2, MMP-3, MMP-9, and TIMP-1 after AHSCT, whereas expression of NF-κB p65 decreased. At baseline, serum levels of COL4A1 and S100A9 were higher than in healthy controls. Serum levels of S100A9 normalized after AHCST in SSc patients compared to controls. Serum levels of PDGF-AA, PDGF-BB, TIMP-1, and MMP-1 decreased, while COL1A1 increased after AHSCT in SSc patients. No changes were detected in MMP-3, MMP-12, MMP-13, and FGF-1 serum levels after AHSCT.

CONCLUSIONS

Our results suggest that the therapeutic effects of AHSCT on skin fibrosis are related to changes in molecules associated with connective tissue maintenance and inflammation in SSc.

The Roles of Noncoding RNAs in Systemic Sclerosis

Noncoding RNAs (ncRNAs) constitute more than 90% of the RNAs in the human genome. In the past decades, studies have changed our perception of ncRNAs from “junk” transcriptional products to functional regulatory molecules that mediate critical processes, including chromosomal modifications, mRNA splicing and stability, and translation, as well as key signaling pathways. Emerging evidence suggests that ncRNAs are abnormally expressed in not only cancer but also autoimmune diseases, such as systemic sclerosis (SSc), and may serve as novel biomarkers and therapeutic targets for the diagnosis and treatment of SSc. However, the functions and underlying mechanisms of ncRNAs in SSc remain incompletely understood. In this review, we discuss the current findings on the biogenetic processes and functions of ncRNAs, including microRNAs and long noncoding RNAs, as well as explore emerging ncRNA-based diagnostics and therapies for SSc.

The novel mechanisms and applications of exosomes in dermatology and cutaneous medical aesthetics

Exposure to the external environment may lead to instability and dysfunction of the skin, resulting in refractory wound, skin aging, pigmented dermatosis, hair loss, some immune-mediated dermatoses, and connective tissue diseases. Nowadays, many skin treatments have not achieved a commendable balance between medical recovery and cosmetic needs. Exosomes are cell-derived nanoscale vesicles carrying various biomolecules, including proteins, nucleic acids, and lipids, with the capability to communicate with adjacent or distant cells. Recent studies have demonstrated that endogenic multiple kinds of exosomes are crucial orchestrators in shaping physiological and pathological development of the skin. Besides, exogenous exosomes, such as stem cell exosomes, can serve as novel treatment options to repair, regenerate, and rejuvenate skin tissue. Herein, we review new insights into the role of endogenic and exogenous exosomes in the skin microenvironment and recent advances in applications of exosomes related to dermatology and cutaneous medical aesthetics. The deep understanding of the mechanisms by which exosomes perform biological functions in skin is of great potential to establish attractive therapeutic methods for the skin.

Clinical features of anti-transcription intermediary factor 1γ (TIF1γ)-positive dermatomyositis with internal malignancy and investigation of the involvement of TIF1γ expression in tumors in the pathogenesis of cancer-associated dermatomyositis

Anti-transcription intermediary factor 1γ (anti-TIF1γ) antibody (Ab) is significantly associated with internal malignancies in adult patients with dermatomyositis (DM). Although pathogenesis of cancer-associated DM is unknown, TIF1γ overexpression in tumors has been considered to be critical for the development of DM. The objective of this study was to investigate clinical characteristics of patients with anti-TIF1γ Ab-positive DM and elucidate risk factors that are potentially associated with internal malignancy. In addition, we compared the expression of TIF1γ in tumor tissues of patients with anti-TIF1γ Ab-positive DM, anti-TIF1γ Ab-negative DM and without DM in order to investigate the pathogenesis of cancer-associated DM. We analyzed 77 Japanese patients with DM, and found 19 patients to be positive for anti-TIF1γ Ab. Patients with anti-TIF1γ Ab-positive DM were older and presented heliotrope rash and flagellate erythema more frequently than patients without anti-TIF1γ Ab (P < 0.05). Interstitial lung disease (ILD) and rapidly progressive ILD, as well as palmar violaceous erythema, were less frequent in patients with anti-TIF1γ Ab than in patients without. Furthermore, internal malignancy and dysphagia were significantly more frequent in the anti-TIF1γ Ab-positive group (P < 0.01). Male sex and dysphagia were significantly associated with internal malignancy in patients with anti-TIF1γ Ab-positive DM (P < 0.01 and <0.05, respectively). Using immunohistochemistry, we examined the TIF1γ expression in tumors of 11 patients with cancer-associated DM (anti-TIF1γ Ab-positive, nine; anti-TIF1γ Ab-negative, two) and 25 patients without DM. TIF1γ was highly expressed in all tumors, and there was no significant difference in TIF1γ expression between patients with and without DM. Furthermore, TIF1γ expressions in tumors were similar irrespective of the presence of anti-TIF1γ Ab. These results suggest that anti-TIF1γ antibody may not be simply induced by overexpression of TIF1γ in tumors in patients with DM, but that other mechanisms may exist.

Type III, IV, and VI Collagens Turnover in Systemic Sclerosis - a Longitudinal Study

Tissue turnover, especially in the skin, is altered in systemic sclerosis (SSc), leading to tissue accumulation. The objective was to examine type III, IV, and VI collagens turnovers in SSc and investigate longitudinal alterations in relation to modified Rodnan Skin Score (mRSS). We included patients fulfilling the 2013 ACR/EULAR criteria for SSc (limited cutaneous [lcSSc, n = 20], diffuse cutaneous SSc [dcSSc, n = 23]) and healthy controls (HC, n = 10). Biomarkers of type III, IV, and VI collagens formation (PRO-C3, PRO-C4, PRO-C6) and degradation (C3M, C4M, C6M) were measured in serum. The fibrotic index of the individual collagens (FICol) were calculated. The fibrotic index of type III and VI collagens (FICol3 and FICol6) were increased in dcSSc compared to lcSSc (FICol3: 1.4 vs. 0.8, P = 0.0001; FICol6: 1.2 vs. 0.9, P = 0.03). The fibrotic index of type IV collagen (FICol4) was not different between the groups but was 1.5 times higher than HC (HC: 6.9, lcSSc 10.4, dcSSc: 10.5). Both FICol3 and FICol6 correlated with mRSS with rho's of 0.59 (P < 0.0001) and 0.35 (P = 0.04). Furthermore, FICol3 steadily decrease over the disease course. Examining collagen turnover and specific collagens could be beneficial in following patients' skin fibrosis and possibly identifying progressors.

Botulinum toxin B suppresses the pressure ulcer formation in cutaneous ischemia-reperfusion injury mouse model: Possible regulation of oxidative and endoplasmic reticulum stress

BACKGROUND

We previously identified that botulinum toxin A (BTX-A) suppressed pressure ulcer (PU) formation after cutaneous ischemia-reperfusion (I/R) injury; however, regulation of cutaneous I/R-induced oxidative and endoplasmic reticulum (ER) stress by BTX-B was not investigated. Additionally, the efficacy of BTX-B injection has never been examined.

OBJECTIVE

Objective was to assess the effects of BTX-B on the formation of PU by cutaneous I/R injury, and the regulation of oxidative and ER stress in I/R injury by BTX-B.

METHODS

BTX-B was subcutaneously injected into I/R area, and wound size, vascular damage, hypoxic area, and apoptotic cells in I/R area were analyzed. We evaluated the extent of oxidative and ER stress in I/R area by using OKD48 mice and ERAI mice, respectively, which enabled evaluating oxidative and ER stress through bioluminescence detection.

RESULTS

BTX-B injection significantly suppressed the formation of PU by cutaneous I/R injury. Cutaneous I/R-induced vascular damage, hypoxic area, and number of oxidative-damaged cells and apoptotic cells were suppressed by BTX-B injection. BTX-B administration significantly inhibited I/R-induced oxidative stress signal in OKD48 mice. BTX-B reduced the I/R-induced oxidative stress-associated factors. BTX-B significantly inhibited the oxidant-induced reactive oxygen species and apoptosis of endothelial cells and fibroblasts. BTX-B significantly inhibited I/R-induced ER stress signal in ERAI mice. Cutaneous I/R injury-induced ER stress-response factors and GRP78/BiP and CHOP-positive cells in I/R area were significantly decreased by BTX-B injection.

CONCLUSION

BTX-B injection might have protective effects against PU formation after cutaneous I/R injury by reducing vascular damage, hypoxia-induced oxidative and ER stress, and apoptosis.

Serum microRNA screening and functional studies reveal miR-483-5p as a potential driver of fibrosis in systemic sclerosis

OBJECTIVE

MicroRNAs (miRNAs) are regulatory molecules, which have been addressed as potential biomarkers and therapeutic targets in rheumatic diseases. Here, we investigated the miRNA signature in the serum of systemic sclerosis (SSc) patients and we further assessed their expression in early stages of the disease.

METHODS

The levels of 758 miRNAs were evaluated in the serum of 26 SSc patients as compared to 9 healthy controls by using an Openarray platform. Three miRNAs were examined in an additional cohort of 107 SSc patients and 24 healthy donors by single qPCR. MiR-483-5p expression was further analysed in the serum of patients with localized scleroderma (LoS) (n = 22), systemic lupus erythematosus (SLE) (n = 33) and primary Sjögren's syndrome (pSS) (n = 23). The function of miR-483-5p was examined by transfecting miR-483-5p into primary human dermal fibroblasts and pulmonary endothelial cells.

RESULTS

30 miRNAs were significantly increased in patients with SSc. Of these, miR-483-5p showed reproducibly higher levels in an independent SSc cohort and was also elevated in patients with preclinical-SSc symptoms (early SSc). Notably, miR-483-5p was not differentially expressed in patients with SLE or pSS, whereas it was up-regulated in LoS, indicating that this miRNA could be involved in the development of skin fibrosis. Consistently, miR-483-5p overexpression in fibroblasts and endothelial cells modulated the expression of fibrosis-related genes.

CONCLUSIONS

Our findings showed that miR-483-5p is up-regulated in the serum of SSc patients, from the early stages of the disease onwards, and indicated its potential function as a fine regulator of fibrosis in SSc.

Protective effect of mesenchymal stem cells on the pressure ulcer formation by the regulation of oxidative and endoplasmic reticulum stress

Cutaneous ischemia-reperfusion (I/R) injury is associated with the early pathogenesis of cutaneous pressure ulcers (PUs). The objective of this study was to investigate the effect of mesenchymal stem cells (MSCs) injection on the formation of PUs after I/R injury and determine the underlying mechanisms. We found that the subcutaneous injection of MSCs into areas of I/R injured skin significantly suppressed the formation of PUs. I/R-induced vascular damage, hypoxia, oxidative DNA damage, and apoptosis were decreased by MSCs injection. Oxidative stress signals detected after I/R in OKD48 (Keap1-dependent oxidative stress detector, No-48-luciferase) mice were decreased by the injection of MSCs. In cultured fibroblasts, MSCs-conditioned medium significantly inhibited oxidant-induced reactive oxygen species (ROS) generation and apoptosis. Furthermore, endoplasmic reticulum (ER) stress signals detected after I/R in ERAI (ER stress-activated indicator) mice were also decreased by the injection of MSCs. These results suggest that the injection of MSCs might protect against the development of PUs after cutaneous I/R injury by reducing vascular damage, oxidative cellular damage, oxidative stress, ER stress, and apoptosis.