Kayo Nakamura

Long non-coding RNA TSIX is upregulated in scleroderma dermal fibroblasts and controls collagen mRNA stabilization

Long non‐coding RNAs (lncRNAs) are thought to have various functions other than RNA silencing. We tried to evaluate the expression of lncRNAs in patients with systemic sclerosis (SSc) and determined whether lncRNAs controls collagen expression in dermal fibroblasts. lncRNA expression was determined by real‐time PCR and in situ hybridization. Protein and mRNA levels of collagen were analysed using immunoblotting and real‐time PCR. We found TSIX, one of the lncRNAs, was overexpressed in SSc dermal fibroblasts both in vivo and in vitro, which was inhibited by the transfection of transforming growth factor (TGF)‐β1 siRNA. TSIX siRNA reduced the mRNA expression of type I collagen in normal and SSc dermal fibroblasts, but not the levels of major disease‐related cytokines. In addition, TSIX siRNA significantly reduced type I collagen mRNA stability, but not protein half‐lives. Furthermore, we first investigated serum lncRNA levels in patients with SSc, and serum TSIX levels were significantly increased in SSc patients. TSIX is a new regulator of collagen expression which stabilizes the collagen mRNA. The upregulation of TSIX seen in SSc fibroblasts may result from activated endogenous TGF‐β signalling and may play a role in the constitutive upregulation of collagen in these cells. Further studies on the regulatory mechanism of tissue fibrosis by lncRNAs in SSc skin lead to a better understanding of the pathogenesis, new diagnostic methods by their serum levels and new therapeutic approaches using siRNAs.

Altered expression of CD63 and exosomes in scleroderma dermal fibroblasts

BACKGROUND Exosomes are small vesicles shed from various cells. They contain proteins, lipids, and nucleic acids, and are regarded as a tool of cell-cell communication. OBJECTIVES To reveal the putative role of exosomes in systemic sclerosis (SSc), and to elucidate the effect of exosomes on wound healing. METHODS The expression of common markers for exosomes (CD63, CD9, and CD81) and type I collagen were examined with real-time PCR, immunohistochemical analysis, ELISA, immunoblotting, and flow cytometry. The effect of serum-derived exosomes on wound healing was tested on full-thickness wounds in the mid-dorsal skin of BALB/c mice. RESULTS The expression levels of CD63 as well as CD9 and CD81 tended to be increased in SSc dermal fibroblasts compared to normal fibroblasts. Increased exosomes in a cultured media of SSc fibroblasts stimulated the expression levels of type I collagen in normal fibroblasts. As the mechanism, collagen-related microRNA levels in SSc fibroblast-derived exosomes were dysregulated, indicating that both the amount and the content of exosomes were altered in SSc. On the other hand, SSc sera showed significantly decreased exosome levels compared to normal sera. The frequencies of vascular involvements, including skin ulcers or pitting scars, were significantly increased in patients with decreased serum exosome levels. The healing of mice wounds was accelerated by treatment with serum-derived exosomes. CONCLUSIONS Vascular abnormalities in SSc may account for the decreased serum exosome levels by the disturbed transfer of exosomes from the skin tissue to the blood stream. Our study suggests the possibility that SSc patients with vascular involvements have decreased serum exosome levels, which causes the delay of wound healing due to down-regulation of collagen, resulting in higher susceptibility to pitting scars and/or ulcers. Exosome research will lead to a detailed understanding of SSc pathogenesis and new therapeutic approaches.

Dysregulated interleukin-23 signalling contributes to the increased collagen production in scleroderma fibroblasts via balancing microRNA expression

Objectives. The overexpression of IL-12 family cytokines is implicated in the pathogenesis of SSc, but their exact role is still unclear. The aim of this study was to investigate the regulation of extracellular matrix expression by IL-23 and its contribution to the phenotype of SSc. Methods. The mRNA expression was determined by PCR array and real-time PCR. The expression levels of proteins were determined by immunoblotting and immunohistochemical staining. The effect of IL-23 on dermal fibrosis in vivo was examined in a mouse model of SSc induced by bleomycin injection. Results. Among the IL-12 family members, IL-23 decreased expression of type I collagen protein in cultured normal dermal fibroblasts. We found that miR-4458 and miR-18a mediated the reduction of collagen expression by IL-23. On the contrary, IL-23 up-regulated type I collagen expression in SSc fibroblasts. The paradoxical effects of IL-23 in SSc fibroblasts were also mediated by the balance between miR-4458 and miR-18a expression. Moreover, we revealed that injection of IL-23 into the mouse skin accelerated skin fibrosis. Conclusion. This is the first study to report that the balance of two miRNAs is involved in the collagen dysregulation in SSc fibroblasts. Clarification of the regulatory mechanism of tissue fibrosis by IL-23 in SSc skin may lead to a better understanding of this disease and new therapeutic approaches.

microRNA level is raised in the hair shafts of patients with dematomyositis in comparison with normal subjects and patients with scleroderma.

The diagnosis of dermatomyositis is sometimes difficult. We tried to evaluate the possibility that levels of Homo sapiens microRNA‐214 (hsa‐miR‐214) in hair roots or hair shafts can be a useful marker of the disease.

Cell division cycle-associated protein 1 as a new melanoma-associated antigen.

Immune checkpoint inhibitors have increased the median survival of melanoma patients. To improve their effects, antigen‐specific therapies utilizing melanoma‐associated antigens should be developed. Cell division cycle‐associated protein 1 (CDCA1), which has a specific function at the kinetochores for stabilizing microtubule attachment, is overexpressed in various cancers. CDCA1, which is a member of cancer–testis antigens, does not show detectable expression levels in normal tissues. Quantitative reverse transcription polymerase chain reaction and immunoblotting analyses revealed that CDCA1 was expressed in all of the tested melanoma cell lines, 74% of primary melanomas, 64% of metastatic melanomas and 25% of nevi. An immunohistochemical analysis and a Cox proportional hazards model showed that CDCA1 could be a prognostic marker in malignant melanoma (MM) patients. CDCA1‐specific siRNA inhibited the cell proliferation of SKMEL2 and WM115 cells, but did not reduce the migration or invasion activity. These results suggest that CDCA1 may be a new therapeutic target of melanoma.

Establishment and gene expression analysis of disease-derived induced pluripotent stem cells of scleroderma

BACKGROUND We recently generated induced pluripotent stem cells (iPSCs) from cultured dermal fibroblasts of systemic sclerosis (SSc-iPSC) to study the disease mechanisms. OBJECTIVE In the present study, we have performed gene expression analysis using cultured SSc dermal fibroblasts, SSc-iPSC, and fibroblasts re-differentiated from SSc-iPSC (SSc-iPSC-FB). METHODS mRNA and protein levels of collagen and integrins were analyzed using PCR array, PCR, immunoblotting, and immunofluorescence. RESULTS We compared expression pattern of TGF-β-related genes between normal iPSC (NS-iPSC) and SSc-iPSC by PCR array, and found constitutive and significant down-regulation of S100A8, Smad6, and TGF-β2 in SSc-iPSC. The expression of these genes was not altered in cultured SSc fibroblasts or SSc-iPSC-FB compared to NS fibroblasts or NS-iPSC-FB, respectively. On the other hand, the expression of collagen, integrin α and β was up-regulated in SSc fibroblasts, while SSc-iPSC-FB showed normalized levels of collagen and integrin β. CONCLUSIONS So far, there have been no reports investigating disease-derived iPSCs of SSc. Our results suggest that S100A8, Smad6, and TGF-β2 may be the key molecules of this disease. On the other hand, the normalization of collagen and integrins by iPSC reprogramming suggests that epigenetic modifications of genes may play a role in the mechanism of collagen accumulation seen in SSc fibroblasts, and that gene reprogramming may become novel therapeutic approach. As the limitation of this study, we established only one iPSC line from each patient, which may not be enough to discuss disease-specific phenotypes. Larger studies including increased number of iPSC lines are needed in the future.

The role of PSMB9 upregulated by interferon signature in the pathophysiology of cutaneous lesions of dermatomyositis and systemic lupus erythematosus.

Dermatomyositis (DM) and systemic lupus erythematosus (SLE) have common skin features, including dermal mucin deposition and interferon signature, although their roles are unknown.

Serum levels of genomic DNA of α1(I) collagen are elevated in scleroderma patients

Recent studies have indicated that various nucleic acids are present in human sera, and attracted attention for their potential as novel disease markers in many human diseases. In this study, we tried to evaluate the possibility that DNA and RNA of collagens exist in human sera, and determined whether their serum levels can be useful biomarkers in scleroderma patients. The RNA or DNA of collagens were purified from sera, and detected by polymerase chain reaction or quantitated by real‐time polymerase chain reaction. Among approximately 18 360 bases of full‐length α1(I) collagen DNA, various regions were detected by polymerase chain reaction in human sera. However, α2(I) collagen DNA, α1(I) collagen RNA or α2(I) collagen RNA were not detectable. α1(I) Collagen DNA in sera was quantitative using our method. The levels of serum α1(I) collagen DNA were significantly increased in scleroderma patients compared with healthy control subjects or systemic lupus erythematosus patients. According to the receiver–operator curve analysis, serum α1(I) collagen DNA levels were shown to be effective as a diagnostic marker of scleroderma. Furthermore, when we determined the association of serum α1(I) collagen DNA levels with clinical/laboratory features in scleroderma patients, those with elevated α1(I) collagen DNA levels showed significantly higher prevalence of pitting scars/ulcers. In summary, elevation of serum α1(I) collagen DNA levels in scleroderma patients may be useful as the diagnostic marker, reflecting the presence of vasculopathy.

Serum concentrations of Flt-3 ligand in rheumatic diseases

Fms-like tyrosine kinase 3 (Flt-3) is a cytokine receptor expressed on the surface of bone-marrow progenitor of hematopoietic cells. Flt-3 ligands are produced by peripheral blood mononuclear cells, and found in various human body fluids. Flt-3 signal is involved in the regulation of vessel formation as well as B cell differentiation, suggesting that Flt-3 signal contributes to the pathogenesis of vascular abnormalities and immune dysregulation in rheumatic diseases. The aim of the present study is to examine serum Flt-3 ligand levels in patients with various rheumatic diseases, and to evaluate the possibility that serum Flt-3 ligand levels can be a useful disease marker. Sera were obtained from 20 dermatomyositis (DM) patients, 36 systemic sclerosis (SSc) patients, 10 systemic lupus erythematosus (SLE) patients, 10 scleroderma spectrum disorder (SSD) patients, 4 mixed connective tissue disease (MCTD) patients, and 12 normal subjects. Flt-3 ligand levels were determined with ELISA. Serum Flt-3 ligand levels were significantly elevated in patients with DM, SSc, SSD and MCTD compared to those in normal subjects. DM patients with elevated Flt-3 ligand levels were accompanied with significantly increased CRP levels and increased frequency of heliotrope rash than those with normal levels. In addition, SSc patients with elevated Flt-3 ligand levels showed significantly reduced frequency of nailfold bleeding. Serum Flt-3 ligand levels can be a marker of cutaneous manifestation in DM and a marker of microangiopathy in SSc. Clarifying the role of Flt-3 ligand in rheumatic diseases may lead to further understanding of these diseases and new therapeutic approaches.