Scarring in RDEB

Research that could lead to the identification of future treatments to reduce some of the debilitating symptoms of RDEB that are caused by chronic scarring.

Dr Giovanna Zambruno works at Bambino Gesù Children’s Hospital in Rome, Italy on recessive dystrophic epidermolysis bullosa (RDEB). Some RDEB symptoms can be caused by skin cells making more scar tissue (fibrosis) than expected because the usual controls that prevent this are broken. This work is to understand some of those control mechanisms to see if they could be targeted by future treatments that could reduce the symptoms in RDEB that are due to scarring.

About our funding:

Research leader	Prof Giovanna Zambruno
Institution	Bambino Gesù Children's Hospital (IRCCS), Rome, Italy
Type of EB	RDEB
Patient involvement	None. This is pre-clinical work on cells grown in the laboratory
Funding amount	€196,500 co-funded with DEBRA Austria
Project length	3 years
Start date	March 2020
DEBRA internal ID	Zambruno2

Latest progress summary:

Skin cells (fibroblasts) from people with RDEB are being grown in the laboratory and the levels and types of molecules called microRNAs they produce are being investigated. The role of these molecules in controlling scarring (fibrosis) may make them targets for EB therapies. Four microRNA molecules have been chosen for further study because they are present at much higher (three of the four) or lower levels in cells from people with RDEB. They have been shown to affect fibrosis and inflammation processes.

Separately, a drug being developed to treat cancers has been shown to be a potential therapy for reducing scarring in RDEB.

This infographic, provided by the researcher in 2022, illustrates the work in progress:

About our researchers:

Prof Giovanna Zambruno (right) with Dr Angelo Giuseppe Condorelli in the cell culture room at Bambino Gesù Children's Hospital. Dr Condorelli is the post-doctoral researcher in charge of the project on a day-to-day basis in the lab.

Research Leader: Dr Giovanna Zambruno, Consultant, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
Dr. Zambruno graduated in Medicine at the University of Pavia, Italy (1982) and completed her residency training in Dermatology and Venereology in 1985 at the same University. Following a research fellowship at the INSERM Laboratory of Dermatological and Immunological Research and at the Department of Dermatology of Claude Bernard University, Lyon, France (1985-1986), she became staff member at the Department of Dermatology, University of Modena, where she established her first research group. In 1995, she moved to the Istituto Dermopatico dell’Immacolata (IDI), where she was Director of the Laboratory of Molecular and Cell Biology (1995-2015) and then Scientific Director (2017-2018). She is currently consultant at Bambino Gesù Children’s Hospital, Rome, where she collaborates with the Pathology and Dermatology Units and the Genetics and Rare Diseases Research Division. Over the past 25 years her clinical and research activity has been focused on rare skin diseases, in particular inherited epidermolysis bullosa. She has authored over 270 publications in peer-reviewed journals, 80 of which on epidermolysis bullosa.

Co-investigators: Dr Teresa Odorisio, Laboratory of Molecular and Cell Biology, IDI-IRCCS, Rome, Italy
Collaborator: Professor Leena Bruckner-Tuderman, Universitätsklinikum Freiburg – Hautklinik, Germany

Why this research is important:

Injury- and inflammation-driven fibrosis is a constant and progressive feature in RDEB. It is responsible for mitten hand formation, limb contractures and mucosal strictures, and is implicated in the development of early and aggressive skin squamous cell carcinoma. Counteracting fibrosis represents a strategy to improve disease course and patients’ quality of life. For the first time, our analyses will investigate the expression levels of a large number of miRNAs and their functional role in RDEB fibrosis. miRNA analysis will be the starting point to identify and disentangle novel druggable targets/pathway for future, innovative anti-fibrotic therapeutic strategies.

Dr Giovanna Zambruno

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Researcher's abstract:

Grant Title: MicroRNAs in dystrophic epidermolysis bullosa fibrosis: expression profiling, activity and therapeutic perspectives

Our DNA is made-up of genes that store the information to build proteins that form our body. The DNA instructions are transcribed into RNA molecules called messenger RNAs (mRNAs), which serve to produce these proteins (translation). However, some RNAs, called non-coding RNAs, are not translated into proteins but regulate the amount of proteins produced. MicroRNAs (miRNAs) are non-coding RNAs that block protein production by interacting with specific mRNAs. MiRNAs are key regulators of all biological processes and their abnormal function contributes to many diseases, including fibrotic (scarring) skin disorders.

In recessive dystrophic epidermolysis bullosa (RDEB) unremitting blistering leads to severe fibrosis that plays an important role in the development of the most severe disease complications. Our group has observed that some miRNAs are more abundant in fibroblasts from RDEB patients (RDEBFs) and exert a pro-fibrotic activity in vitro. Based on these preliminary studies, the present project aims at identifying additional miRNAs dysregulated in RDEBFs and at characterizing their role in key fibrotic processes such as the production and release of important pro-fibrotic molecules (e.g. the transforming growth factor-b1) and the dermal (skin) stiffening. This study will contribute to expand knowledge about disease pathomechanisms and to identify novel miRNAs and miRNA targets as potential targets for innovative therapies to limit fibrosis.

Researcher's progress update:

Our DNA is made-up of genes that store the information to build proteins forming our body. The DNA instructions are transcribed into RNA molecules called messenger RNAs (mRNAs), which serve to produce proteins. However, a family of small RNAs, called microRNAs, do not become proteins but regulate the amount of proteins produced. MicroRNAs block protein production by interacting with specific mRNAs, defined as microRNA targets. MicroRNAs are key regulators of all biological processes and their malfunctioning contributes to many diseases, including the recessive dystrophic epidermolysis bullosa (RDEB) and its severe clinical complications, such as skin inflammation, fibrosis and cancer development.

In fibrotic tissues, fibroblasts produce excessive amounts of “fibrotic” proteins, mainly collagens, which are deposited outside the cells, and display an increased capability to contract the tissue around them, leading to tissue stiffness and dysfunction. Our previous study showed that a microRNA named miR-145-5p, is more abundant in fibroblasts from RDEB patients and demonstrated its role in fibrotic processes. In this project we evaluated the abundance of hundreds of microRNAs at once and started to explore their functions. We identified a group of 36 microRNAs deregulated in RDEB fibroblasts (that is molecules at least two times more or less abundant with respect to cells from healthy donors). Thereafter, we selected for further investigations four microRNAs, present in increased or reduced amount in RDEB cells as compared to controls. We observed that the pharmacological modulation of these microRNAs is able to counteract the production of typical fibrotic proteins by RDEB fibroblasts.

In parallel, we deepened our studies on a newly identified molecular mechanism involved in RDEB fibrosis, named Notch pathway. A cellular pathway consists of a well-organized series of actions driven by specific molecules (named pathway members), causing different biological events, such as cell division, movement or fibrosis. Our studies revealed that the inhibition of Notch pathway by different approaches, including drugs commercially available but to date used to treat diseases different from RDEB, markedly attenuates several pro-fibrotic traits in RDEB cells. In detail, RDEB fibroblasts treated with specific molecules that reduce the activity of Notch exhibit a reduced capability i) to contract collagen gels (which represent a model of the ability of fibroblasts to shrink the surrounding tissue), ii) to deposit “fibrous” proteins (collagens) outside the cell, iii) to secrete the most important fibrotic molecule, i.e. the transforming growth factorbeta1, iv) to move and proliferate, and (v) to produce a wide range of molecules which are typically abundant in fibrotic tissues. Taken together, our data support the biological relevance of Notch pathway in RDEB-related disease processes, and its inhibition as an innovative therapeutic target to counteract skin fibrosis. (From 2022 progress report.)