Gianluca Moroncini

Oxidative stress and the pathogenesis of scleroderma : the Murrell's hypothesis revisited

Systemic sclerosis (SSc, scleroderma) is a devastating, immune-mediated, multisystem disorder characterized by microvasculature damage, circulating autoantibodies, and fibroblast activation, leading to massive fibrosis of skin, vessels, muscles, and visceral organs. Scleroderma causes disability and death as the result of end-stage organ failure. At present, no specific diagnostic nor therapeutic tools are available to handle the disease. In spite of significant effort, the etiology and pathogenesis of SSc remain obscure and, consequently, the disease outcome is unpredictable. Several years ago, Murrell suggested a unifying hypothesis linking the pathogenesis of scleroderma to the generation of a large excess of reactive oxygen species. This hypothesis has been substantiated by several reports indicating the presence of an abnormal redox state in patients with scleroderma. This review will summarize the available evidence supporting the link between free radicals and the main pathological features of scleroderma.

New Insights into the Role of Oxidative Stress in Scleroderma Fibrosis

Systemic sclerosis (Scleroderma – SSc) is a connective tissue disorder of unknown aetiology characterized by extensive fibrosis of the skin and visceral organs, by vascular abnormalities and immunological manifestations. Recent evidence suggest that the cellular redox state may play a significant role in the progression of scleroderma fibrosis. Mechanisms involved include an autoamplification circuit linking ROS, Ras and ERK 1-2 which in turn amplifies and maintains the autocrine loop made up by cytokines, growth factors and their cognate receptors. This review summarizes the recent progress on the role of oxidative stress in the pathophysiology of scleroderma and disorders characterised by organ fibrosis

A Reactive Oxygen Species–Mediated Loop Maintains Increased Expression of NADPH Oxidases 2 and 4 in Skin Fibroblasts From Patients With Systemic Sclerosis

Reactive oxygen species (ROS) contribute to the pathogenesis of fibrosis in systemic sclerosis (SSc; scleroderma), and NADPH oxidase (NOX) is an important source of ROS. Since the role of single NOX isoforms has not been previously investigated in SSc, this study was undertaken to assess the expression of NOX in SSc fibroblasts compared to normal healthy cells and to analyze their role in cell activation.

Oxidative DNA damage induces the ATM-mediated transcriptional suppression of the Wnt inhibitor WIF-1 in systemic sclerosis and fibrosis

DNA damage not only promotes a mitotic checkpoint response but also activates a pathway that can produce fibrotic disease. Connecting DNA Damage to Fibrotic Skin Thickening Systemic sclerosis (SSc) is an autoimmune disease characterized by the accumulation of collagen in the connective tissue, a process known as fibrosis. Fibrosis affects skin and internal organs and is frequently associated with activation of the Wnt signaling pathway. Svegliati et al. found loss of the Wnt inhibitor WIF-1 in skin biopsies from SSc patients compared with healthy skin. Antibodies in serum from SSc patients or oxidative DNA-damaging agents triggered a transcriptional suppression pathway that suppressed WIF-1 expression and promoted collagen production in normal fibroblasts. In fibroblasts cultured from SSc patients, inhibiting this pathway restored WIF-1 expression and reduced collagen production; in a mouse model of fibrosis, inhibiting this pathway prevented fibrotic skin thickening. Systemic sclerosis (SSc) is an autoimmune disease characterized by extensive visceral organ and skin fibrosis. SSc patients have increased production of autoreactive antibodies and Wnt signaling activity. We found that expression of the gene encoding Wnt inhibitor factor 1 (WIF-1) was decreased in fibroblasts from SSc patient biopsies. WIF-1 deficiency in SSc patient cells correlated with increased abundance of the Wnt effector β-catenin and the production of collagen. Knocking down WIF-1 in normal fibroblasts increased Wnt signaling and collagen production. WIF-1 loss and DNA damage were induced in normal fibroblasts by either SSc patient immunoglobulins or oxidative DNA-damaging agents, such as ultraviolet light, hydrogen peroxide, or bleomycin. The DNA damage checkpoint kinase ataxia telangiectasia mutated (ATM) mediated WIF-1 silencing through the phosphorylation of the transcription factor c-Jun, which in turn activated the expression of the gene encoding activating transcription factor 3 (ATF3). ATF3 and c-Jun were recruited together with histone deacetylase 3 (HDAC3) to the WIF-1 promoter and inhibited WIF-1 expression. Preventing the accumulation of reactive oxygen species or inhibiting the activation of ATM, c-Jun, or HDACs restored WIF-1 expression in cultured SSc patient cells. Trichostatin A, an HDAC inhibitor, prevented WIF-1 loss, β-catenin induction, and collagen accumulation in an experimental fibrosis model. Our findings suggest that oxidative DNA damage induced by SSc autoreactive antibodies enables Wnt activation that contributes to fibrosis.

Pathologic prion protein is specifically recognized in situ by a novel PrP conformational antibody

Prion diseases are characterized by the accumulation in the brain of abnormal conformers (PrP(Sc)) of the cellular prion protein (PrP(C)). PrP(Sc) immunohistochemistry, currently based on antibodies non-distinguishing between PrP(C) and PrP(Sc), requires pre-treatments of histological sections to eliminate PrP(C) and to denature PrP(Sc). We employed the PrP(Sc)-specific antibody 89-112 PrP motif-grafted IgG on mildly fixed, untreated brain sections from several cases of human prion diseases. The results confirmed specific binding of IgG 89-112 to a structural determinant found exclusively on native disease-associated PrP conformations and lost following tissue denaturation or cross-linking fixation. Importantly, IgG 89-112 demonstrated no reactivity with normal brain tissue or with amyloid deposits in Alzheimer disease brain sections. Thus, immunohistochemical detection of native PrP(Sc) deposits was obtained by means of a PrP(Sc)-specific antibody. Such unique reagent may have many applications in the study of prion biology and in the diagnosis and prevention of prion diseases.

Regional Implantation of Autologous Adipose Tissue-Derived Cells Induces a Prompt Healing of Long-Lasting Indolent Digital Ulcers in Patients with Systemic Sclerosis:

Digital ulcers (DUs) are a rather frequent and invalidating complication in systemic sclerosis (SSc), often showing a very slow or null tendency to heal, in spite of the commonly used systemic and local therapeutic procedures. Recently, stem cell therapy has emerged as a new approach to accelerate wound healing. In the present study, we have tentatively treated long-lasting and poorly responsive to traditional therapy SSc-related DUs by implantation of autologous adipose tissue-derived cell (ATDC) fractions. Fifteen patients with SSc having a long-lasting DU in only one fingertip who were unresponsive to intensive systemic and local treatment were enrolled in the study. The grafting procedure consisted of the injection, at the basis of the corresponding finger, of 0.5-1 ml of autologous ATDC fractions, separated by centrifugation of adipose tissue collected through liposuction from subcutaneous abdominal fat. Time to heal after the procedure was the primary end point of the study, while reduction of pain intensity and of analgesic consumption represented a secondary end point. Furthermore, the posttherapy variation of the number of capillaries, observed in the nailfold video capillaroscopy (NVC) exam and of the resistivity in the digit arteries, measured by high-resolution echocolor-Doppler, were also taken into account. A rather fast healing of the DUs was reached in all of the enrolled patients (mean time to healing 4.23 weeks; range 2-7 weeks). A significant reduction of pain intensity was observed after a few weeks (p < 0.001), while the number of capillaries was significantly increased at 3- and 6-month NVC assessment (p < 0.0001 in both cases). Finally, a significant after-treatment reduction of digit artery resistivity was also recorded (p < 0.0001). Even with the limitations related to the small number of patients included and to the open-label design of the study, the observed strongly favorable outcome suggests that local grafting with ATDCs could represent a promising option for the treatment of SSc-related DUs unresponsive to more consolidated therapies.

Contributions of neuronal prion protein on sleep recovery and stress response following sleep deprivation.

In order to gain insights on the function of the cellular prion protein (PrP(C)) sleep and the levels of the stress hormones corticosterone (CORT) and the adrenocorticotropic hormone (ACTH) before and after sleep deprivation (SD) were compared in two wild type (WT) mice strains and the following three PrP(C) transgenic lines: mice null for PrP(C) (mPrP(0/0)) and mice with specific and central expression of PrP in neurons (NSE-HPrP/mPrP(0/0)) or in glia cells (GFAP-HPrP/mPrP(0/0)). After SD mPrP(0/0) mice showed a larger degree of sleep fragmentation and of latency to enter rapid eye movement (REM) and non-REM sleep (NREM) than WT. During sleep recovery, the amount of NREM sleep and the slow-wave activity (SWA) were reduced in mPrP(0/0) mice. After SD, CORT and ACTH levels have distinct patterns in WT and mPrP(0/0). The NREM and SWA deficit was restored in NSE-HPrP/mPrP(0/0) mice but not in GFAP-HPrP/mPrP(0/0). Hormonal profile was only partially restored in NSE-HPrP/mPrP(0/0) mice and was similar to that of mPrP(0/0) and GFAP-HPrP/mPrP(0/0) mice. These findings demonstrate that neuronal, but not non-neuronal, PrP(C) is involved in sleep homeostasis and sleep continuity. They also suggest that neuronal PrP(c)-dependent hormonal regulation of HPA axis may contribute to the sleep homeostasis.

Induction of Scleroderma Fibrosis in Skin‐Humanized Mice by Administration of Anti−Platelet‐Derived Growth Factor Receptor Agonistic Autoantibodies

To describe a skin–SCID mouse chimeric model of systemic sclerosis (SSc; scleroderma) fibrosis based on engraftment of ex vivo–bioengineered skin using skin cells derived either from scleroderma patients or from healthy donors.

Epitope Specificity Determines Pathogenicity and Detectability of Anti–Platelet-Derived Growth Factor Receptor α Autoantibodies in Systemic Sclerosis

To identify the epitopes recognized by autoantibodies targeting platelet‐derived growth factor receptor α (PDGFRα) in systemic sclerosis (SSc) and develop novel assays for detection of serum anti‐PDGFRα autoantibodies.

Induction of scleroderma fibrosis in skin‐humanized mice by anti‐Platelet‐Derived Growth Factor receptor agonistic autoantibodies

To describe a skin–SCID mouse chimeric model of systemic sclerosis (SSc; scleroderma) fibrosis based on engraftment of ex vivo–bioengineered skin using skin cells derived either from scleroderma patients or from healthy donors.