Scleroderma – More than Skin Deep

Scleroderma – More than Skin Deep

Scleroderma, or systemic sclerosis, is a chronic connective tissue disease generally classified as an autoimmune rheumatic disease. The disease can result in changes to the skin, blood vessels, muscles and internal organs. Symptoms vary greatly between patients and can range from extremely mild to life threatening and may include thickening of the skin, stiffness, fatigue and poor blood flow to the fingers and toes with cold exposure. The precise cause remains unknown but it is suspected that it is due to an abnormal immune response.

The Reality Behind the Research

Eliza Tsou, PhD, is a Research Assistant Professor and Research Fellow in the Division of Rheumatology at the University of Michigan with a sole focus on scleroderma research. She obtained her BS degree in pharmacy in Taiwan before receiving a PhD in Pharmaceutical Sciences from the University at Buffalo. She has been actively involved in several scleroderma research projects, examining the mechanisms of tissue fibrosis (the formation of excess fibrous connective tissue) and vasculopathy (abnormalities in the blood vessels) in scleroderma. She uses cells isolated from skin biopsies from healthy volunteers and biopsies from scleroderma patients to determine the key factors affecting the development of the disease. Each year, Dr. Tsou participates in a patient education event held at the University of Michigan, this giving her a glimpse of the real-life impact of the disease she is researching. “Interacting with the patients, knowing their stories, learning their daily struggles, motivates me to work harder so that we better understand this disease and find a cure for it soon.”

Building on a Solid Foundation

Funding received as an ANRF scholar has cemented Dr. Tsou’s role as a specialist scleroderma researcher with a focus on epigenetics (changes to gene expression due to non-genetic influences such as diet). The award has allowed this researcher to expand on a previously published study which yielded promising results. The extracellular matrix is a three-dimensional network of macromolecules, such as collagen, enzymes, and glycoproteins, that provide structural and biochemical support to the surrounding cells. A matricellular protein is one of these macromolecules occurring in the extracellular matrix. Rather than serving as a structural element, matricellular proteins have regulatory role, aiding in controlling the production of other proteins. CYR61 is one such matricellular protein. CRY61 plays three distinct roles. First, it prevents the formation of excessive connective tissue meaning it has anti-fibrosing properties. Second, it promotes the formation of new blood vessels so is pro-angiogenic. Third, it aids in the regulation and adjustment of immune responses. These three properties led Dr. Tsou to hypothesize that CYR61 could potentially address the three main aspects of scleroderma simultaneously, making it an ideal candidate as a novel drug target.

CYR61 – A Protein Triple Threat to Scleroderma

Fibroblasts are a type of connective tissue cell and are key in the synthesis of the extracellular matrix as they produce collagen. Collagen is the main structural protein within the extracellular matrix as well as in connective tissue. Collagen plays an important structural role in our skin. For these reasons it was important to look at differences in fibroblasts and dermal endothelial (skin) cells of scleroderma patients. As such, both types of cells were isolated from biopsies obtained from healthy patients and were compared to those taken from patients with scleroderma. Proteins that fulfil numerous roles in our bodies are produced based on our genetic code. In order for this code to leave the nucleus of the cell and be taken to the cell’s machinery which reads it and produces the proteins it must first be transformed into a readable form. This readable form of DNA is called messenger RNA (mRNA). Each piece of mRNA codes for a unique protein to be produced. Therefore, by measuring the amount of mRNA in a cell you can determine the level of the protein that it codes for. By measuring the mRNA levels in the above-mentioned biopsies, Dr. Tsou was able to determine that there were lower mRNA levels of CRY61 in both endothelial cells and fibroblasts in scleroderma patients than there were in the healthy patients. Based on this, the team looked at what happened if they artificially increased levels of CRY61 in fibroblasts from scleroderma patients. There was a significant reduction in the expression of genes that are profibrotic and thus cause excessive connective tissue, namely the COL1A1 and ACTA2 genes. Furthermore, it was also determined that there was an increase in the expression of MMP1 and MMP3 genes, which play a role in degrading the extracellular matrix, further preventing excessive formation of connective tissue. The expression of VGEF, a pro-angiogenic gene key in the formation of new blood vessels was also increased.

 

Connecting the Dots in Scleroderma Research

Further evidence of CRY61 having anti-fibrotic properties was demonstrated by showing there was a delay in wound healing in the presence of higher levels of this protein. Wound healing requires connective tissue to be produced, therefore a delay in this process shows decreased connective tissue production. Decreasing connective tissue formation would be beneficial to reduce production levels in scleroderma patients. Collagen is a factor which contributes to the thickening of skin, commonly seen in scar formation. To investigate the role of collagen in scleroderma the team used a collagen gel contraction assay. This investigative procedure places fibroblast cells in a collagen gel, and monitors changes that occur in the extracellular matrix. Contraction of the extracellular matrix is key in inflammation and wound healing, with greater contraction leading to scarring and thickening of the skin.  When CYR61 was present with the fibroblasts and collagen gel it inhibited contraction of the extracellular matrix, thus making it a definite possibility to reduce skin thickening in scleroderma patients. The TGFβ pathway signaling pathway is involved in multiple processes including cellular growth, cell differentiation and apoptosis (a form of programmed cell death). All of these processes contribute to the degradation and formation of new cells and tissues. Overexpression of the CRY61 protein caused inactivation of the TGFβ pathway thus having the potential to limit the overproduction of skin and connective tissue. Finally, increasing CRY61 in scleroderma patients led to fibroblasts showing early superoxide production. The production of superoxide is associated with senescence which is the permanent arrest of cellular growth, this again limiting the production of collagen in the extracellular matrix and demonstrating the anti-fibrotic effects of CRY61. Simply put, this is all evidence that supports the notion that CYR61 halts excessive production of fibrous connective tissue. These findings were presented at the American College of Rheumatology Meeting in Chicago in late 2019. Therapeutic intervention to promote CYR61 levels or increase its activity could be extremely beneficial in the treatment of scleroderma. Dr Tsou discussed plans to continue building on the momentum created by her findings. She said, “I plan to continue working on scleroderma, further exploring the epigenetic impacts in this disease, and establishing myself as an expert in scleroderma epigenetics in the future.” ANRF is proud to have Dr. Tsou as a member of its research family and we are in no doubt that her research will continue to have an impact in the fight against autoimmune conditions.  


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ANRF
Article Author
Arthritis National Research Foundation
arthritisresearch@curearthritis.org

The Arthritis National Research Foundation's mission is to provide initial research funding to brilliant, investigative scientists with new ideas to cure arthritis and related autoimmune diseases. Writing articles about the patients affected and the science being done to find a cure shows why we need to come together to #CureArthritis!

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