The fibroblast in systemic sclerosis

Alterations in peripheral T- and B-cell subsets in patients with systemic sclerosis

OBJECTIVES

To determine the alteration of peripheral T and B cell subsets in patients with systemic sclerosis (SSc) and to evaluate their correlation with the progression of SSc.

METHODS

We recruited 47 SSc patients and 45 healthy controls (HCs) in this study. Demographic and clinical data were then collected. Flow cytometry was used to detect the proportions of 44 different T and B cell subsets in circulating blood.

RESULTS

The proportion of total B cells (p = .043) decreased in SSc patients, together with similar frequencies of total T cells, CD4+ T cells, and CD8+ T cells in both groups. Several subsets of T and B cells differed significantly between these two groups. Follicular helper T cells-1 (Tfh1) (p < .001), helper T cells-1 (Th1) (p = .001), regulatory T cells (Treg) (p = .004), effector memory CD8+ T cells (p = .041), and cytotoxic T cells-17 (Tc17) (p = .01) were decreased in SSc patients. Follicular helper T cells-2 (Tfh2) (p = .001) and, helper T cells-2 (Th2) (p = .001) levels increased in the SSc group. Regulatory B cells (Breg) (p = .015) were lower in the SSc group, together with marginal zone (MZ) B cells (p < .001), memory B cells (p = .001), and non-switched B cells (p = .005). The modified Rodnan skin score (mRSS) correlated with helper T cells-17 (Th17) (r = -.410, p = .004), Tfh1 (r = -.321, p = .028), peripheral helper T cells (Tph) (r = -.364, p = .012) and plasma cells (r = -.312, p = .033).

CONCLUSIONS

The alterations in T and B cells implied immune dysfunction, which may play an essential role in systemic sclerosis.

Anti-fibrotic effect of a selective estrogen receptor modulator in systemic sclerosis

Background

The rarity of systemic sclerosis (SSc) has hampered the development of therapies for this intractable autoimmune disease. Induced pluripotent stem cell (iPSC) can be differentiated into the key disease-affected cells in vitro. The generation of patient-derived iPSCs has opened up possibilities for rare disease modeling. Since these cells can recapitulate the disease phenotypes of the cell in question, they are useful high-throughput platforms for screening for drugs that can reverse these abnormal phenotypes.

Methods

SSc iPSC was generated from PBMC by Sendai virus. Human iPSC lines from SSc patients were differentiated into dermal fibroblasts and keratinocytes. The iPSC-derived differentiated cells from the SSc patients were used on high-throughput platforms to screen for FDA-approved drugs that could be effective treatments for SSc.

Results

Skin organoids were generated from these cells exhibited fibrosis that resembled SSc skin. Screening of the 770-FDA-approved drug library showed that the anti-osteoporotic drug raloxifene reduced SSc iPSC-derived fibroblast proliferation and extracellular matrix production and skin fibrosis in organoids and bleomycin-induced SSc-model mice.

Conclusions

This study reveals that a disease model of systemic sclerosis generated using iPSCs-derived skin organoid is a novel tool for in vitro and in vivo dermatologic research. Since raloxifene and bazedoxifene are well-tolerated anti-osteoporotic drugs, our findings suggest that selective estrogen receptor modulator (SERM)-class drugs could treat SSc fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02987-w.

Fibroblasts as confederates of the immune system

Fibroblastic stromal cells are as diverse, in origin and function, as the niches they fashion in the mammalian body. This cellular variety impacts the spectrum of responses elicited by the immune system. Fibroblast influence on the immune system keeps evolving our perspective on fibroblast roles and functions beyond just a passive structural part of organs. This review discusses the foundations of fibroblastic stromal-immune crosstalk, under the scope of stromal heterogeneity as a basis for tissue-specific tutoring of the immune system. Focusing on the skin as a relevant immunological organ, we detail the complex interactions between distinct fibroblast populations and immune cells that occur during homeostasis, injury repair, scarring, and disease. We further review the relevance of fibroblastic stromal cell heterogeneity and how this heterogeneity is central to regulate the immune system from its inception during embryonic development into adulthood.

Therapeutic efficacy of combined glucocorticoid, intravenous cyclophosphamide, and double-filtration plasmapheresis for skin sclerosis in diffuse systemic sclerosis

We treated skin sclerosis with triple therapy consisting of a glucocorticoid, intravenous cyclophosphamide, and double-filtration plasmapheresis. The objective of this study was to analyze its effectiveness in a case series of patients who received triple therapy.We enrolled 8 patients with diffuse cutaneous systemic sclerosis (dcSSc) who received triple therapy at our hospital from 2008 to 2016. We analyzed the mean change in the modified Rodnan skin score (mRSS), percentage of the predicted forced vital capacity (%FVC), percentage of the predicted carbon monoxide diffusing capacity (%DLCO), and serum KL-6 levels from baseline to follow-up.All patients were treated with an intermediate dose of oral prednisolone (30.6 ± 2.1 mg/day) initially. The mean cumulative dose of intravenous cyclophosphamide was 1.4 ± 0.2 g. The mean mRSS decreased significantly at follow-up compared with that at baseline (27.0 ± 3.3 vs 15.8 ± 3.5; P = .03). At the end of the treatment, the mean %FVC and %DLCO were improved moderately, although the differences were not significant. The serum KL-6 levels decreased from 578.9 ± 146.5 to 205.3 ± 43.1 U/ml (P = .02). No significant correlation was found between the change in mRSS or disease duration and the initial skin score severity.Triple therapy may improve skin sclerosis, with effectiveness equal or superior to other reported treatments. This preliminary case series demonstrates the potential of triple therapy for treating dcSSc. However, prospective studies with long-term follow-up should be performed to assess its role.

Radiological findings in gastrointestinal scleroderma

Gastrointestinal involvement is the most common visceral organ manifestation in systemic sclerosis. Symptoms from the gastrointestinal tract are very frequent among scleroderma patients and in many cases present a therapeutic challenge. However, gastrointestinal involvement may also be asymptomatic, presenting with complications later in the disease course. Early recognition of gastrointestinal scleroderma is therefore important both for symptomatic control and prevention of complications. Gastrointestinal imaging alongside clinical assessment forms the mainstay of diagnosis. Radiological investigations, traditionally plain radiographs and barium studies, with the more recent advances in computed tomography, magnetic resonance imaging and ultrasound, provide means for accurate evaluation of visceral organ involvement and more effective patient care. Awareness of the characteristic images is important not only for radiologists but also for the treating physicians and gastroenterologists.

Statins as Immunomodulators in Systemic Sclerosis

Systemic sclerosis (SSc) has the highest case-specific mortality among the rheumatic diseases. Vascular dysfunction and structural wall abnormalities are among the earliest and fundamental alterations in SSc. Statins have a number of immunomodulating effects on vascular wall cells, which may modify the progression of vascular injury. The aim of this study was to evaluate the potential efficacy of statin therapy in ameliorating endothelial dysfunction (ED) in SSc by investigating the effect of statins on some markers that reflect endothelial activation in SSc. Forty patients with SSc were randomized into two groups to receive 6 months' treatment with atorvastatin (n = 20; dose, 40 mg/day) or placebo (n = 20) as an adjuvant to existing therapy. Markers of ED including ET-1, plasma nitrate levels, and thrombomodulin (TM) were evaluated by the enzyme-linked immunosorbent assay (ELISA) technique. Fibrinogen, high-sensitivity C-reactive protein (hsCRP), ESR, lipid peroxide (LP), and malonylaldehyde (MDA) levels were also assessed. Brachial flow-mediated vasodilatation was assessed by ultrasonography. Patients were studied at base line and after 6 months of statin therapy. After 6 months of therapy, ET-1, ICAM-1, sE-selectin, vWF, fibrinogen, ESR, hsCRP as well as LP and MDA levels declined and NO increased significantly in the statin-treated SSc group when compared to the placebo-treated group. Endothelium-dependent vasodilatation (EDV) improved significantly in the atorvastatin-treated group. The findings of this study demonstrated statin-mediated improvements in the endothelial function of SSc patients as well as immunomodulating effects. Statins may thus prove to be an invaluable addition to the therapy of the vasculopathy of SSc.

Fibroblast heterogeneity: more than skin deep

Dermal fibroblasts are a dynamic and diverse population of cells whose functions in skin in many respects remain unknown. Normal adult human skin contains at least three distinct subpopulations of fibroblasts, which occupy unique niches in the dermis. Fibroblasts from each of these niches exhibit distinctive differences when cultured separately. Specific differences in fibroblast physiology are evident in papillary dermal fibroblasts, which reside in the superficial dermis, and reticular fibroblasts, which reside in the deep dermis. Both of these subpopulations of fibroblasts differ from the fibroblasts that are associated with hair follicles. Fibroblasts engage in fibroblast-epidermal interactions during hair development and in interfollicular regions of skin. They also play an important role in cutaneous wound repair and an ever-increasing role in bioengineering of skin. Bioengineered skin currently performs important roles in providing (1) a basic understanding of skin biology, (2) a vehicle for testing topically applied products and (3) a resource for skin replacement.

The scarring processes in mucosal tissues after immune injury

OBJECTIVES

An important feature of the healing processes is scar formation which may be necessary for organism survival. If it proceeds to the pathological state, it may impair normal function. The purpose of this review is to focus on some of the factors that may influence this process after immune injury, comparing it in the skin and mucosa.

METHODS

A detailed literature search of peer-reviewed journals was conducted. Studies reported in all languages considered relevant and important were used, including humans, animals, and tissue culture.

RESULTS

Analysis of the data indicate that the scarring process is mainly dependent on (1) the type of the lesion, (2) the cause and duration of injury, and (3) the tissue involved and its microenvironment. Equally important is the large spectrum and heterogenicity in the biological activity of fibroblasts and their role in scar formation.

CONCLUSIONS

The process of scar formation is complex and multistep process and is affected and influenced by local and systemic factors. Although it appears irreversible, there are pharmacological agents available, and under investigation, that may minimize its detrimental effects.

Scleroderma lung fibroblasts exhibit elevated and dysregulated type I collagen biosynthesis

OBJECTIVE

To examine whether scleroderma lung fibroblasts show a pattern of aberrant type I collagen (CI) biosynthesis similar to that observed previously in studies of dermal fibroblasts in this disease.

METHODS

CI secretion and steady-state pro alpha1(I) collagen messenger RNA (mRNA) levels and COL1A2 gene activation were examined in fibroblasts grown from lung biopsy specimens obtained from 16 scleroderma patients with lung fibrosis and from 10 histologically normal lung specimens (controls). The effect of culture in a 3-dimensional (3-D) CI gel matrix culture on CI mRNA levels was also examined.

RESULTS

The mean (+/- SEM) collagen secretion in monolayer culture for scleroderma lung fibroblasts was 90.9 +/- 56 ng/ml/10(6) cells, significantly greater (P < 0.05) than controls (40.2 +/- 17.5). Pro alpha1(I) collagen mRNA levels in monolayer cultures were higher in scleroderma (mean +/- SEM collagen:GAPDH ratio 3.7 +/- 0.9) compared with control (1.9 +/- 0.8) lung fibroblasts. Transient expression assays confirmed that genes coding for CI are transcriptionally activated in scleroderma lung fibroblasts compared with control strains. Although all lung fibroblasts induced equivalent contraction of 3-D CI gel matrices, scleroderma strains failed to show a reduction in steady-state pro alpha1(I) collagen mRNA levels in gel culture.

CONCLUSION

We have demonstrated elevated CI biosynthesis and impaired mRNA down-regulation for CI by scleroderma lung fibroblasts. These properties are likely to be highly relevant to the pathogenesis of scleroderma-associated lung fibrosis.

The nervous system in systemic sclerosis (scleroderma). Clinical features and pathogenetic mechanisms

The involvement of the nervous system in SSc is well recognized today. Different pathogenetic mechanisms are suggested that may alternatively explain the multiform appearance of the clinical spectrum (mononeuritis, mononeuritis multiplex, carpal tunnel syndrome, and so forth). It is now clear that the ANS is the earliest structure targeted by the disease in the gastrointestinal tract. The importance of this observation has not yet been adequately interpreted but may, together with the increasing evidence of the nervous system involvement in SSc, become a leading factor in understanding of the importance of the nervous system in the onset, development, and maintenance of the disease.

Effects of mebendazole on protein biosynthesis and secretion in human-derived fibroblast cultures

Previous results of our group revealed that mebendazole, a broad spectrum anthelmintic drug with antimicrotubular properties, used for the treatment of liver cirrhosis, decreased total collagen content and biosynthesis in liver upon treatment. In the present study, we have evaluated the effects of mebendazole (5-50 micrograms/mL) on protein synthesis, secretion, and deposition in human-derived fibroblast cultures. The results showed a decrease in cell viability (18.5 +/- 0.9%) at 50 micrograms/mL. [3H]Thymidine incorporation diminished gradually with increasing mebendazole concentrations, reaching a plateau (53.67%) between 30 and 50 micrograms/mL. In late logarithmic phase cultures, the drug caused a decrease of [3H]proline incorporation (43.10%) and collagen biosynthesis (58.61%) in the extracellular matrix. This correlated with an increase in radioactivity in total proteins (51.28%) of the intracellular fraction. Similar results were obtained when mebendazole was assayed in post-confluent fibroblast cultures. The electrophoretic patterns of the extracellular matrix showed a decrease of radioactive collagenous components (alpha chains and beta dimers). By contrast, in the intracellular fraction an increase of radioactive collagen precursors (pro alpha chains) was observed. Immunofluorescence studies and immunotransfer analysis, using polyclonal anti-type I collagen antibodies, revealed an accumulation of intracellular collagen which included: collagen pro alpha chains, alpha chains, and low molecular weight peptides. The results obtained suggest that mebendazole interferes with the transcellular mobilization of proteins, resulting in a decrease of secretion and deposition of extracellular matrix proteins, and an accumulation of intracellular collagenous components. The intracellular accumulation of newly synthesized proteins could cause a feedback regulation in fibroblast cultures.