Non-Tuberculous Mycobacterial Skin and Soft Tissue Infections: Using a Site-of-Disease Approach to Understand Pathophysiology and Improve Outcome

Grantee: Arjan van Laarhoven, PhD, Radboud University Medical Center

Amount: DKK 3,987,136

Grant category: Research Grants in open competition

Year: 2023

Geography: Netherlands

Arjan van Laarhoven’s project aims to improve the treatment of patients infected with mycobacteria by looking at the patient’s individual immune responses to the infection and combining this with optimized treatment with antibiotics.

Non-tuberculous mycobacteria (NTM) can cause debilitating skin and soft tissue infections (SSTI). NTM SSTI incidence rises with an aged population and increased use of immunosuppression. These infections require treatment with multiple antibiotics for minimally 4-6 months. Still, non-response or worsening of skin lesions occurs frequently, because antibiotics fail or too much inflammation occurs.

Arjan van Laarhoven and his team hypothesize that differences in the patients’ immune systems, so-called ‘patient endotypes’, drive these diverging treatment courses. Currently, the involved immune processes in the skin are not identified for NTM SSTI. In addition, it is unknown what antibiotic concentrations in the skin are needed to kill the NTM.

In this study, the team will investigate the individual immune response in the skin of NTM SSTI patients by measuring the activity of genes in individual cells, and how these cells interact. They will compare this to the immune cells in the patients’ blood and will use the combined information to understand how patients differ in their immune response to the infection. These findings will be related to the clinical response to antibiotic treatment.

After eight weeks of antibiotic treatment, a second biopsy will be taken, in which measurement of the number of live mycobacteria and the local skin drug concentrations of azithromycin and clofazimine will be repeated.

By providing targets for optimizing treatment with both antibiotics and anti-inflammatory or immunostimulating drugs, this project aims to improve the outlook for NTM SSTI patients.

Developing a vaccine, and characterizing the protective immunity, to prevent skin infection with Streptococcus Pyogenes

Grantee: Jes Dietrich, Senior Scientist, Statens Serum Institut

Amount: DKK 3,920,493

Grant category: Research Grants in open competition

Year: 2023

Geography: Denmark

Jes Dietrich’s project aims to develop a vaccine against a common pathogenic bacterium.

Streptococcus Pyogenes (Group A streptococcus, GAS) is a human pathogen causing billions of infections each year throughout the world. GAS is one of the most important bacterial causes of skin and soft tissue infections worldwide. There is no vaccine against GAS and the optimal immunity to protect the skin against GAS infection is still not fully known.

Jes Dietrich and his team have recently characterized the recognition of all GAS proteins in previously infected human adults and children, and successfully identified several GAS antigens that showed protective potential against a GAS skin infection.

Here, they will follow up on these discoveries. The aim is to produce a vaccine hybrid construct that will target several antigens on the bacterial surface as well as several of the bacterium’s early key immune inhibiting functions. Moreover, they will also investigate the immune correlates of skin protection.

Thus, the goal for this project is to develop a vaccine that protects against a GAS skin infection, and which is ready to proceed towards future clinical trials.

Environmental pathobiology of a model inflammatory human stem cell disease: Can fragrances promote frontal fibrosing alopecia?

Grantee: Ralf Paus, Professor, University of Miami

Amount: DKK 3,868,632

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Ralf Paus’ project aims to elucidate the role of the fragrance linalool in the development of frontal fibrosing alopecia (a type of involuntary hair loss).

Frontal fibrosing alopecia (FFA) is an ever more common, disfiguring inflammatory hair disease of primarily post-menopausal women. Since many FFA patients are allergic to fragrances like linalool, contained in 63-90% of personal care/household products, Ralf Paus and his team investigated whether this lead fragrance can promote core FFA pathogenesis events in human scalp hair follicles (HFs), which express “smell” (olfactory) receptors (ORs) for this fragrance, and indeed linalool induced overexpression of a key inflammatory “danger/distress” signal (MICA), reduced the pool of HF stem cells, and transformed some of them into fibroblasts (EMT).

Thus, Ralf Paus and his team hypothesize that linalool causes overexpression of MICA and excessive chemokine secretion by stimulating specific ORs; this attracts MICA-responsive immune cells that induce bulge immune privilege (an anatomical area relatively protected from inflammatory immune responses) collapse and stem cell death or EMT, leading to hair loss and scarring.

In Aim 1, they will probe this hypothesis in organ-cultured healthy human HFs, and non-lesional scalp skin of linalool-sensitized FFA patients. In Aim 2, they will dissect mechanistically by OR1A1 or OR1C1 silencing (i.e., preventing certain ORs from being expressed) which linalool-induced, FFA-promoting events depend on OR signaling.

If they can confirm that linalool can promote or even initiate core FFA pathogenesis events, namely in sensitized individuals, this will identify a novel immunological stem cell damage mechanism and could have major consumer protection and preventive medicine implications.

The role of eosinophils in type 2-associated skin diseases

Grantee: Patrick Brunner, Associate Professor, Icahn School of Medicine at Mount Sinai

Amount: DKK 3,893,985

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Patrick Brunner’s project aims to better understand the role of eosinophils, a type of granulocyte, in inflammatory skin diseases.

Granulocytes are key components of the innate immune system, that can react rapidly to various infectious agents and noxious stimuli. Despite their central role in host defense, their mechanistic relevance to human skin disease is still only insufficiently understood. Particularly eosinophils are prominently found in various inflammatory skin conditions associated with type 2 immune skewing (i.e., a response governed by T helper cells type 2 and a characteristic set of released cytokines, like IL-4 and IL-13). These include atopic dermatitis, bullous pemphigoid, hypereosinophilic syndrome (HES), urticaria, allergic reactions including DRESS (Drug reaction with eosinophilia and systemic symptoms), or parasitic infestations.

IL-5 is believed to be a key growth and differentiation factor for eosinophils. While IL-5 blockade is effective in e.g., HES, urticaria and DRESS, it is largely ineffective in atopic dermatitis or bullous pemphigoid, suggesting substantial functional eosinophil heterogeneity across these conditions. However, underlying mechanisms remain entirely unexplored, due to the difficulty in isolating and propagating these cells.

By using novel high-throughput analysis techniques such as single-cell RNA sequencing (scRNAseq) and spatial transcriptomics, complemented by functional in vitro experiments, Patrick Brunner and his team want to characterize eosinophils from skin and blood of patients with classic type 2 diseases, and define their in-situ skin tissue niche (i.e., microenvironment).

With this study, they hope to better understand eosinophil heterogeneity across skin diseases, define yet unrecognized subtypes within the human immune system, and help to develop better future treatment approaches.

Commensal Polyomavirus as a Novel Therapeutic for Lupus

Grantee: Shadmehr Demehri, Associate Professor, Massachussets General Hospital, USA

Amount: DKK 4,000,000

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Shadmehr (Shawn) Demehri’s project aims to elucidate the potentially beneficial role of polyomavirus infections in lupus.

Lupus is a major autoimmune disease characterized by the immune system’s attack on the body’s tissues and organs. Lupus affects over 5 million individuals worldwide, with an estimated 16,000 new cases diagnosed annually in the United States alone. Chronic inflammation caused by lupus impacts the skin, kidneys, and brain. Despite significant progress in understanding the pathophysiology of autoimmune diseases, lupus patients continue to experience substantial morbidity affecting their quality of life.

Polyomaviruses are small DNA viruses that are commonly found in nature. In immunocompetent individuals, polyomaviruses persist at low levels in the host after the primary infection, usually without causing any noticeable symptoms. Clinical research suggests that lupus patients with polyomavirus DNA in their urine may exhibit reduced kidney inflammation and lupus antibodies.

These clinical observations, together with preliminary findings by Shawn Demehri and his team, suggest a potential protective role for commensal (i.e., naturally occurring and non-pathogenic) polyomaviruses in lupus. To investigate the role of polyomavirus as a novel lupus therapy, the group aims to: (a) elucidate the mechanisms by which polyomavirus suppresses inflammation, (b) examine the impact of polyomavirus on lupus development, and (c) determine the potential of polyomavirus to enhance the therapeutic effects of current lupus treatments.

By exploring these avenues, they hope to uncover new insights into the potential use of polyomavirus as a therapeutic strategy for lupus.

Outside-to-inside: understanding aberrant proteolysis in primary barrier defects as drivers of atopic dermatitis

Grantee: Ulrich auf dem Keller, Professor, Technical University of Denmark

Amount: DKK 2,865,186

Grant category: Research Grants in open competition

Year: 2023

Geography: Denmark

This project of Ulrich auf dem Keller aims to elucidate the potential role of a set of recently discovered proteins in atopic dermatitis that may contribute to disease development.

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects people of all ages. It is one of the most common skin diseases, affecting approximately 10-20% of children and 1-3% of adults worldwide. AD can be a frustrating and uncomfortable condition that can significantly impact a person’s quality of life.

Despite extensive research it is not fully clear, if AD is primarily caused by a defect barrier function of the skin, allowing uncontrolled entry of environmental allergens that trigger an immune response, or by immunological disorders that in turn weaken the skin’s protective barrier, exaggerating the disease in a vicious cycle. Most likely, both contribute to predisposition and development of AD, but there are differences between patients which call for customized therapies.

Together with basic skin researchers in Switzerland and dermatologists in Germany, Ulrich auf dem Keller has identified proteins in non-lesional skin of AD patients whose activities might impair skin barrier integrity mostly independent of an immune response. This project will use human skin models and advanced protein analytics to understand if and how they might exert these detrimental activities and thereby contribute to predisposition to AD in affected individuals. Moreover, they will test their findings in samples from AD patients with a long-term aim to contribute to new strategies for development of therapeutics as alternatives to frequently applied emollients in barrier repair therapy.

A Backpack-based Macrophage Therapy for Dermal Wound Healing

Grantee: Samir Mitragotri, Professor, Harvard John A Paulson School of Engineering and Applied Sciences

Amount: DKK 3,954,190

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Macrophages, especially anti-inflammatory macrophages, are essential biological players in the process of dermal wound healing. However, maintaining an M2 phenotype within the inflamed wound microenvironment is quite challenging due to secretion of inflammatory cytokines from the wound. To overcome this limitation, Samir Mitragotri and his team have invented polymer micro-disks (“backpacks”) that carry potent anti-inflammatory agents. These “backpacks” are uniquely designed to possess a discoidal shape which keeps them attached to the monocyte/macrophage surface without them being taken up by the cell, and ensures continuous delivery of the anti-inflammatory agents to the cell carrying the backpack without elevating systemic drug concentrations. The project aims to develop a protocol to deliver such “backpack”-laden monocytes only once into the wound, where they can differentiate into macrophages and maintain themselves in the anti-inflammatory phenotype for an adequate time period to induce wound healing. The “backpack” technology has been pioneered by Samir Mitragotri and his lab. This novel strategy appears to have a unique advantage to control macrophage phenotype only for a pre-determined time, thus representing a promising new approach to dermal wound healing treatment.

Skin bacteria lipopeptides: key modulators of keratinocyte immune responses and atopic dermatitis

Grantee: Peter Arkwright, Senior Lecturer, The University of Manchester

Amount: DKK 4,163,557

Grant category: Research Grants in open competition

Year: 2023

Geography: United Kingdom

Dr Peter Arkwright’s project aims to functionally characterize a group of recently discovered anti-inflammatory bacterial substances and investigate their potential therapeutic value in atopic dermatitis.

Staphylococcus aureus is unique in being the only bacterial species that consistently triggers flares in atopic dermatitis (AD). In previous work, also supported by the LEO Foundation, Dr Peter Arkwright, Dr Jo Pennock, and their team at the University of Manchester discovered “Sbi” as the unique factor produced by this bacterium that initiates AD in skin cells. Recently, they have identified factors produced by skin bacteria that completely block Staphylococcus aureus-induced AD, both in the lab and in an eczema mouse model. These factors are small, stable chemicals, made up of both fats and small proteins (lipopeptides).

In a collaboration with Professor Hiroshi Matsuda and Professor Akane Tanaka in Tokyo, Japan, they will apply lipopeptides derived from different bacteria to the skin of mice with AD to determine which are most effective at reducing the clinical dermatitis, itch, and skin damage. They will also explore how these factors work, using cell, protein, and lipid staining techniques. By purifying and characterizing these chemically stable immunosuppressive lipopeptides it is hoped that promising candidates identified here can be taken forward into clinical trials to develop novel therapies for AD.

Curing calcinosis: Dystrophic calcinosis in patients with Systemic Sclerosis undergoing treatment with Sodium Thiosulfate – Assessed by novel biomarkers and diagnostic imaging

Grantee: Mette Mogensen, Chief Consultant, Associate Professor, Bispebjerg and Frederiksberg Hospital

Amount: DKK 3,322,500

Grant category: Research Grants in open competition

Year: 2023

Geography: Denmark

This research project aims to synergistically improve patient treatment and improve understanding of the underlying biological and chemical mechanisms of cutaneous dystrophic calcinosis (DC) – a disease causing exaggerated deposition of calcium salts in skin.

These pathological calcifications cause severe ulcerations and pain in patients with systemic sclerosis (SSc) and negatively impact their quality of life. Today, reliable methods of quantifying the distribution, volume and composition of calcium crystal deposits are lacking.

Combining the expertise of data scientists and molecular biologists with medical experts in the field of radiology, dermatology, and rheumatology, Mette Mogensen and her team will create a new approach for quantifying calcium crystal deposits in skin and soft tissue in patients suffering from SSc, which is highly needed to monitor disease progression and potential treatment effects in future clinical trials. Several smaller studies have shown a potential for treating DC using sodium thiosulphate (STS). The aim of this study is to explore the characteristics of DC and investigate how STS treatment effects can be monitored over time with novel biomarkers (from blood and skin biopsies) and by advanced imaging technologies.

The vision is to cure calcinosis and the goal of this project is to increase quality of life for patients by development of an effective, targeted treatment that may offer therapeutic potential to all DC patients globally.

Citrullination in hair growth and alopecia

Grantee: Maria Genander, Assistant Professor, Karolinska Institutet

Amount: DKK 4,020,645

Grant category: Research Grants in open competition

Year: 2023

Geography: Sweden

Maria Genander’s project aims to understand the physiological role of the enzymes PADI3 and PADI4, which convert the amino acid arginine to citrulline, in normal hair growth – to ultimately better understand the changes that happen during unwanted hair loss, alopecia.

Hair follicle (HF) growth, leading to the generation of the hair shaft, requires coordinated development of the cells that make up hair. Protein modifications act to fine-tune the action of the signaling that leads to cellular maturation and differentiation and impacts directly on the properties of structural proteins required for hair formation. In this project, Maria Genander and her team investigate the expression of the protein-modifying enzymes PADI3 and PADI4 in the HF to understand the functional impact of PADI-mediated citrullination on cell differentiation and hair growth. Preliminary data indicate that PADI4 restricts proliferation of HF progenitor cells committed to the hair shaft lineage. Using sophisticated methodology, they aim to decipher mechanistically how PADI4 influences HF lineage progression. In addition, they will use in-utero lentiviral injections in mice to probe the function of PADI3a and PADI3b to understand how distinct PADI3 isoforms impacts hair formation and the development of alopecia.

Collectively, Maria Genander’s work will focus on addressing citrullination in hair follicle growth and hair formation. Understanding normal hair follicle development is a prerequisite for development of therapeutic strategies targeting alopecia.