Probing the function of melanosomal transporters in pigmentation using metabolic profiling

Grantee: David M. Sabatini, Whitehead Institute of Biomedical Research

Amount: DKK 1,278,270

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

Studies in human populations have identified dozens of pigmentation genes, many of which encode proteins with well-understood functions, such as in melanocyte development, melanin biosynthesis, and the biogenesis and trafficking of specialized melanin-containing organelles called melanosomes.

Yet, there are other pigmentation genes that we know much less about, such as those that encode putative transporter proteins on the melanosome surface. These putative melanosomal transporters have been reported to import precursor metabolites for melanin synthesis or regulate melanosomal pH; however, many of these findings have been controversial or speculative. Deciphering the molecular function of these putative transporters and their physiological substrates is crucial to our understanding of pigmentation.

To address this problem, we propose to determine the metabolite composition of melanosomes and define the role of individual transporters in melanosomal function. We will develop a purification method to rapidly isolate intact melanosomes and analyse them by liquid chromatography and mass spectrometry to compile the first catalog of melanosomal metabolites. We will subsequently characterize SLC45A2, a putative melanosomal transporter that modulates human pigmentation in response to sunlight. By comparing the metabolite profile of wild-type versus SLC45A2-deficient melanosomes, we will identify candidate SLC45A2 substrates and validate them using biochemical assays, a workflow that will be applied to other putative melanosomal transporters.

This study will present the first detailed analysis of melanosome metabolites, as well as identify key metabolites and their transporters essential for melanogenesis. This work could inform new ways to modulate pigmentation and treat pigmentation pathologies.

Nucleic Acid Ionic Liquids (NAILs) for Topical Skin Applications

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

Amount: DKK 2,000,043

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

We will develop a novel ionic-liquid formulation for topical delivery of nucleic acids into the skin.

Our ionic liquid enhances lipophilicity of nucleic acids by ~100,000,000 fold and enhances their penetration into the skin. We will demonstrate the feasibility of the platform through delivery and efficacy of two siRNAs. The resulting platform is expected to have broad applications to other nucleic acid drugs including mRNA for the treatment of a wide range of dermatological conditions.

Our ionic liquid platform will open new opportunities for the treatment of dermatological conditions.

Investigating the role of human periostin in healthy skin and severe eczema

Grantee: Jan J. Enghild, Aarhus University

Amount: DKK 3,045,231

Grant category: Research Grants in open competition

Year: 2018

Geography: Denmark

Severe eczema, also known as atopic dermatitis (AD) is the most common inflammatory skin disease resulting in itchy, inflamed, and swollen skin that is very susceptible to infection. It is estimated that 15-20% of all children and 2-10% of adults are affected, without effective treatment.

Because of this, significant public health burden and the lack of safe and effective treatments, there is a need for novel targeted therapeutics that can help manage symptoms and improve the quality of life for the patients.

The protein periostin is expressed in the skin and is implicated in AD. Significantly, studies have shown that the elimination of periostin in an AD mouse model reduces or completely removes the symptoms making periostin an apparent therapeutic target. However, the physiological functions of periostin remains unclear and a reduction or elimination of the protein in the skin could have severe side effects.

Therefore, a deeper understanding of the physiological role in healthy and diseased skin must be established. The interdisciplinary research team behind this project propose to address these issues and establish the function of periostin using in vitro and in vivo experimental setups including primary cell cultures, zebrafish, mouse models and human specimens combined with advanced biochemical methods. Novel therapeutics are urgently needed, and this project aim is to establish a strategy for the development of new treatment paradigms for AD, leading towards novel, innovative therapeutic strategies.

Endosomal Chemokine Receptor Signaling as Basis for Metastasis in Malignant Melanoma

Grantee: Alex Rojas Bie Thomsen, Columbia University Medical Center

Amount: DKK 3,600,308

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

Melanoma is the deadliest form of skin cancer with few treatment options to patients with advanced metastatic disease.

Melanoma metastasis to lymph nodes is associated with expression of the chemokine receptor CCR7, a member of the G protein-coupled receptors (GPCRs) superfamily that promote cell migration of immune cells. Classically, upon agonist stimulation, GPCRs at the cell membrane activate heterotrimeric G proteins, causing downstream signaling throughout the cell. In order to terminate G protein signaling, cells have devised a specialized desensitization mechanism that includes receptor phosphorylation by GPCR kinases and subsequent recruitment of β-arrestins (βarrs) to the phosphorylated receptors. The GPCR–βarrs interaction both blocks the G proteinbinding site and promotes receptor endocytosis.

However, we recently discovered that some GPCRs interact with G proteins and βarrs simultaneously to form GPCR–G protein–βarr ‘megaplexes’, which allows the receptor to continue to stimulate G protein signaling while being internalized into endosomes by βarrs. Our preliminary results suggest that CCR7 forms megaplexes and promotes G protein signaling from internalized compartments. Interestingly, endosomal signaling, in general, is highly involved in cell migration, and different proteins are trafficked between plasma membrane and endosomes during this process. Thus, the proposed project aims to investigate the involvement of endosomal CCR7 signaling in melanoma cell migration. Furthermore, using a combination of highly advanced cryo-electron tomography and APEX2 proteomics, we will visualize the mechanism of CCR7-mediated melanoma cell migration protein-by-protein. Such detailed mechanistic knowledge will assist in designing innovative therapeutics to treat metastatic malignant melanoma.

Developing a Cell-Based Therapy for Alopecia

Grantee: George Cotsarelis, Perelman School of Medicine, University of Pennsylvania, Philadelphia

Amount: DKK 3,793,808

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

Androgenetic alopecia (AGA, Male or Female Pattern Baldness) is the most common type of hair loss, affecting approximately 50% of men and 30% of women by the age of 50.

Current therapies, including pharmaceutical and surgical interventions, are either marginally effective or expensive with significant limitations. Over the last decade, breakthroughs made in the field of adult stem cells have laid the foundation for a cell-based approach to tissue and organ regeneration. Cell-based therapies will comprise a new wave of medical breakthroughs.

In this study we propose to produce human hair follicles from induced pluripotent stem (iPS) cells by directing these cells to form the two types of cells that are needed for human hair formation, namely the human hair follicle epidermal cells and the hair inductive dermal fibroblasts.

We will combine our hair biology and tissue-engineering expertise to generate early stage human hair follicles in culture that can be implanted into an animal model to grow into a mature hair. The long-term goals are to develop an innovative cell-based treatment for hair loss and an in vitro platform for testing hair growth compounds.

Psoriasis: a microbiome-driven disease?

Grantee: Patrick Zeeuwen, Radboud University Medical Center, Nijmegen

Amount: DKK 2,545,944

Grant category: Research Grants in open competition

Year: 2018

Geography: Netherlands

Psoriasis is highly prevalent and has a significant medical and socio-economic impact.

The prevailing dogma has been that abnormalities of the adaptive immune system were primary, but genetic studies have highlighted the importance of local skin-specific factors. We and others have identified epidermis-specific innate immunity genes, like beta-defensins and Late Cornified Envelope (LCE) genes, to be associated with disease development.

We recently made two exciting observations. First, deletion of LCE3B and LCE3C does not merely imply the loss of two genes but has a genomic effect that leads to a strong induction of the flanking LCE3A gene. Secondly, we found that LCE proteins, and LCE3A in particular, have broad-spectrum antimicrobial activity. We hypothesize that the LCE3B/C-del status affects the cutaneous host defense repertoire thereby shaping the skin microbiome. We aim to investigate the biology of LCE genes and to translate these findings to our understanding of psoriasis pathogenesis.

Key objectives are to:

  1. assess the antimicrobial activity and specificity of all LCEs and their synergy with other antimicrobial proteins. This will be investigated by metagenomic approaches and classical in vitro microbiological assays, using recombinant and synthetic LCE proteins and peptides derived thereof
  2. investigate LCE3B/C-del in isogenic 3D-skin equivalents in vitro generated from the immortalized human keratinocyte N/TERT cell line. Deletions of other LCE genes or their regulatory sequences will be made using CRISPR/Cas9 technology. Effects on epidermal biology relevant to psoriasis will be studied and include antimicrobial host defense, innate immune response and skin barrier function

Investigating the tumor suppressive functions of Notch signaling during skin cancer initiation and progression

Grantee: Sunny Y. Wong, Assistant Professor, University of Michigan, Ann Arbor

Amount: DKK 2,486,354

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

Basal cell carcinoma (BCC) is the world’s most common cancer and is defined by uncontrolled activation of the Hedgehog (Hh) signaling pathway.

Although previous studies have suggested that elevated Hh may be sufficient for BCC formation, mutations in the Notch pathway are also commonly observed. Furthermore, Notch-deficient mice are susceptible to forming BCCs, and our recent studies have shown that Notch can modulate tumor-drug response.

These studies seek to understand whether Notch affects multiple aspects of BCC tumorigenesis. Using a combination of animal studies and human BCC specimens, we will investigate how Notch modulates tumor progression and stem cell origin.

We will also model in mice a recent clinical trial, where Alzheimer’s patients treated with a Notch inhibitor reported increased incidence of BCC. We hypothesize that Notch may suppress tumorigenesis at multiple levels by controlling cell differentiation, apoptosis and turnover, similar to its function in normal skin and hair follicles.

These studies will ultimately build on the novel premise that BCCs may originate from a precursor lesion. Given that Notch mutations are the most commonly observed genetic aberrations in human skin, a deeper understanding of the tumor suppressive properties of this pathway is urgently needed.

Characterizing the disease memory in atopic dermatitis

Grantee: Patrick M. Brunner, Medical University of Vienna

Amount: DKK 2,920,541

Grant category: Research Grants in open competition

Year: 2018

Geography: Austria

Atopic dermatitis (AD), the most common chronic inflammatory skin disease, typically starts very early in life.

While many patients outgrow their disease, some develop chronic disease for the rest of their lives. Mechanisms responsible, however, are completely unknown, and no biomarker exists that can predict the course of the disease.

Thus, we want to compare skin from young adults that have outgrown their AD, with skin from patients with active disease (namely normal appearing AD under topical glucocorticoid treatment, which can be expected to flare up again after cessation of treatment, thus harbouring a “disease memory”).

Skin from healthy control subjects will serve as baseline comparators. Due to low immune cell numbers in this type of tissue, we want to use in vivo suction blistering of AD patients to obtain (i) skin resident immune cells and (ii) skin proteins. Suction blister fluid will be analysed with low cytometry and single cell RNAseq (for cells) as well as a proteomic multiplex assays (OLINK) for soluble proteins. The blister roof (i.e. the epidermis) will also be harvested, and keratinocytes will be stored in liquid nitrogen for functional experiments.

Results obtained from flow cytometry, single cell RNAseq and proteomic approaches will then be used for such functional in vitro experiments (e.g. co-culturing, skin equivalents, stimulation experiments) in future research projects.

Overall, we hope that the identification of cellular and/or molecular factors influencing the natural course of AD could possibly identify targets for novel therapeutic approaches in AD, that could induce long term remission – or even lead to a cure – of AD.

Compartmentalized and Systemic Interactions of the Skin Microbiome in Cancer Immunotherapy Response

Grantee: Julia Oh, Jackson Laboratory, Farmington, Connecticut

Amount: DKK 2,107,529

Grant category: Research Grants in open competition

Year: 2018

Geography: USA

My vision is to use metagenomics to better predict patient responses to immunotherapy and rationally design microbial adjuvant cocktails and engineered microbes to improve therapeutic outcomes.

However, a central question is the role of the local microbiota vs. systemic effects in potentiating these immunotherapeutics. In skin cancer, we have been studying how the skin microbiome affects predisposition and progression. Specific gut microbes have been implicated in the outcomes for immunotherapy response in melanoma skin cancer, supporting a role of systemic immune interactions via the gut in potentiating immunotherapy response.

However, because many aspects of cutaneous immunity are compartmentalized from systemic immune effects, we hypothesize that the skin microbiome could uniquely impact skin cancer outcomes during immunotherapy by modulating the cutaneous immune milieu.

GLP-1R signaling in T cells in relation to psoriasis

Grantee: Carsten Geisler, Professor and Head of Department, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen

Amount: DKK 2,000,000

Grant category: Research Grants in open competition

Year: 2017

Geography: Denmark

Recent studies of patients with psoriasis and type 2-diabetes have shown intriguing results: administration of glucagon-like peptide 1 (GLP-1) analogues was found to improve the severity of psoriasis. In another study, while not finding a significant beneficial effect of a GLP-1 analogue on disease score as compared to placebo, patients did report a significant decrease in their disease score as compared to baseline.

This has led a Denmark-based group to team up for further investigation of the effect of GLP-1 analogues on psoriasis, based on, among others, an assumption of a direct effect of GLP-1 analogues on the immune system – with the intention of clarifying if there may be a route to new treatment options for psoriatic patients.

More specifically, the team will investigate if the potential immunoregulatory effect of GLP-1R signalling on T cells in psoriatic plaques could be responsible for the patient-experienced alleviation of psoriasis. The team furthermore hypothesizes that vitamin D may play an important role in GLP-1R signaling and is important for alleviation of psoriasis as Vitamin D upregulates GLP-1R on T cells and low serum levels of vitamin D have been reported in psoriatic patients.

The majority of the experiments will be performed by Anna Kathrine Obelitz Rode under supervision of Martin Kongsbak-Wismann and Carsten Geisler, Department of Immunology and Microbiology, University of Copenhagen. Lone Skov, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen will be co-supervisor on the project. The project will be performed in close collaboration with Charlotte Menné Bonefeld, Department of Immunology and Microbiology, University of Copenhagen.

The clinical studies in humans will be performed at the Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen in collaboration with Lone Skov.