Epigenetic regulation of sebaceous gland development and homeostasis

Grantee: Brian Capell, Assistant Professor, University of Pennsylvania

Amount: DKK 2,885,457

Grant category: Research Grants in open competition

Year: 2024

Geography: USA

Brian Capell’s project seeks to better understand how epigenetic changes (modifications that do not change the sequence of genomic DNA) regulate the development of sebaceous glands.

Dysfunction of sebaceous glands (SGs) has been linked to a variety of common skin disorders ranging from atopic dermatitis to acne, sebaceous hyperplasia, seborrheic dermatitis and sebaceous tumors.

Brian Capell and his team have recently discovered that through genetic modification of the epigenome, they could promote a dramatic increase in the number and size of SGs (Ko, et al. Developmental Cell. In press. 2024). This surprising result demonstrated the direct role that epigenetics and chromatin organization plays in controlling SG development and abundance. It also suggested that targeting the epigenome might offer new ways to treat disorders characterized by aberrant SG development and activity.

Diseases related to aberrant SG development or activity can have a deleterious effect on both human physical and mental health. Despite this, very little is known of the role of epigenetics in SG development and homeostasis. To address this, Brian Capell’s project aims to test the influence of epigenomic modifiers and modifications upon SG development and disease to further dissect their contribution to the pathogenesis of these very common conditions.

Collectively, this project will address outstanding questions regarding the role of the epigenome in SG development and homeostasis and in common diseases driven by SG dysfunction – diseases that are both understudied and in need of better therapies.

Endothelial senescence in the pathogenesis of systemic sclerosis

Grantee: Eliza Pei-Suen Tsou, Assistant Professor, University of Michigan

Amount: DKK 3,990,092

Grant category: Research Grants in open competition

Year: 2024

Geography: USA

Understanding structural and functional differences between JAK family JH1 and JH2 domains

Grantee: Christopher Bunick, Associate Professor, Yale University

Amount: DKK 4,165,955

Grant category: Research Grants in open competition

Year: 2024

Geography: USA

Skin microbiome-metabolome modulation of skin homeostasis

Grantee: Julia Oh, Associate Professor, The Jackson Laboratory

Amount: DKK 3,953,521

Grant category: Research Grants in open competition

Year: 2024

Geography: USA

Investigate the onset of pathological remodeling events in SSc and assess their contribution to disease pathogenesis

Grantee: Valentina Greco, Professor, Yale University

Amount: DKK 3,818,950

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Valentina Greco’s project investigates the potential role of fibroblast and blood vessel maturation processes in systemic sclerosis (SSc) by monitoring development longitudinally in-vivo.

The skin protects organisms from their environment; it prevents water loss and infection and blocks physical insults. This barrier includes an outer layer and an inner, highly organized scaffold of fibers and blood vessels. Proper development of these two networks following birth is essential for health during adulthood; however, these processes are poorly understood.

Defects in the assembly and function of dermal fiber and blood vessel networks lead to severe diseases such as Systemic Sclerosis (SSc) or scleroderma. Identification of early SSc stages is crucial for the development of diagnostic, preventive, and therapeutic strategies. However, gaining this knowledge has been challenged by the inability to track these events longitudinally and in vivo.

Valentina Greco’s lab has overcome this roadblock and developed the ability for continuous visualization of skin networks, specifically how fibroblast and blood vessel networks develop after birth under healthy conditions. In this project – and building on this knowledge – they will utilize mouse models that mimic SSc in humans to investigate whether mechanisms crucial for postnatal skin maturation participate in this disease.

Valentina Greco’s project, if successful, will advance the understanding of the skin’s structural and blood vessel networks, shed light on their role in health and disease, and provide a solid foundation to improve clinical management of those suffering from often-lethal ailments such as scleroderma.

Modeling Hailey-Hailey disease to delineate its pathogenesis and identify therapeutic strategies

Grantee: Cory Simpson, Assistant Professor, University of Washington

Amount: DKK 4,054,629

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Cory Simpson’s project aims to investigate how mutations in the gene encoding the calcium pump SPCA1 cause the skin blistering disease Hailey-Hailey Disease (HHD) using human cellular and tissue models.

The epidermis forms the body’s outer armor from multiple layers of cells called keratinocytes, which assemble strong connections (desmosomes) to seal the skin tissue and prevent wounds. Several rare blistering disorders are linked to autoantibodies or gene mutations that disrupt desmosomes, causing keratinocyte splitting and skin breakdown. While autoimmune blistering diseases can be controlled by suppressing the immune system, treatments remain elusive for inherited blistering diseases.

One of these is Hailey-Hailey disease (HHD), which causes recurrent wounds, pain, and infections, leading to stigmatization of patients. Mutations in the ATP2C1 gene, which encodes the calcium pump SPCA1, were linked to HHD more than 20 years ago, yet the disease still lacks any approved therapies.

While it is known that SPCA1 resides in the Golgi apparatus (an organelle inside the cell responsible for protein processing and trafficking), our limited understanding of how SPCA1 deficiency compromises skin integrity has stalled drug development for HHD; moreover, mice engineered to lack SPCA1 did not replicate HHD.

Cory Simpson and his team at the University of Washington have built human cellular and tissue models of HHD to define what drives the disease and to discover new treatments. Their preliminary analysis of ATP2C1 mutant keratinocytes revealed impaired expression and trafficking of adhesive proteins, but also identified stress signals from mis-folded proteins and reactive oxygen species.

In this project, Cory Simpson and team will determine how these cellular dysfunctions compromise keratinocyte cohesion to cause skin blistering and test if cell stress pathways could serve as therapeutic targets for HHD.

Programming dermal fibroblasts to stimulate hair follicle regeneration

Grantee: Peggy Myung, Associate Professor, Yale University

Amount: DKK 2,135,432

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Peggy Myung’s project aims to elucidate how two key molecular signals regulate the development of dermal condensate cells, a group of cells pivotal for hair formation.

The hair follicle dermal condensate (DC) is a cluster of quiescent dermal cells that can induce new hair follicle formation and holds the potential to revolutionize hair loss treatments. However, a key barrier to exploiting DCs to make new hair is that the molecular and cellular mechanisms that lead to DC formation are poorly understood.

Peggy Myung and her team recently identified two morphogen signals that are necessary and sufficient to drive DC formation. These two signals cooperate to unfold an initial stage of progenitor proliferation followed by a stage of cell cycle exit and DC maturation. Importantly, these stages of differentiation depend on levels of these two signals: Low levels induce progenitor proliferation; higher levels induce quiescence and DC maturation.

They hypothesize that different signaling levels regulate these stages of differentiation by inducing distinct signature genes that cause either DC progenitor expansion or terminal differentiation. They recently established a high-throughput dermal culture system to test this hypothesis. Using this novel platform and in vivo hair reconstitution assays, they aim to define how modulation of levels of these two signals regulates dermal gene expression profiles, cell cycle dynamics and DC function.

If successful, Peggy Myung’s project may define tunable molecular targets to develop novel treatments for hair loss and to make DC organoids for drug testing.

Microbial impact on vitiligo development

Grantee: Caroline Le Poole, Professor, Northwestern University

Amount: DKK 2,979,828

Grant category: Research Grants in open competition

Year: 2023

Geography: USA

Caroline Le Poole’s project aims to investigate the potential link between the gut microbiome composition and vitiligo development.

The etiology of vitiligo involves a complex hereditary component, as well as environmental factors that precipitate disease. Caroline Le Poole and her team initially asked whether the gut microbiome impacts T cell-mediated autoimmune depigmentation. Manipulating the gut microbiome by oral antibiotics, they demonstrated a significant impact on vitiligo development in an established mouse model of the disease. Specifically, when using ampicillin to favor gut colonization by Pseudomonas species, they observed accelerated vitiligo development. Meanwhile, neomycin treatment was associated with an abundance of Bacteroides species in the gut, while mice in this group did not develop measurable depigmentation. These and other findings suggest that specific microbes can influence vitiligo development.

Here, they will test the hypothesis that the microbiome is a causative pathogenic factor fueling the autoimmune response to melanocytes causing the hallmark progressive depigmentation seen in vitiligo. The team will use mouse and human fecal transplants and manipulate the diet of vitiligo-prone mice. Moreover, individual microbial species will be introduced into germ-free mice before assessing depigmentation kinetics. Ultimately, therapeutic benefit may be derived from promoting the species that support regulatory T cell activity.

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.