Tape strip expression profiling of juvenile dermatomyositis skin reveals mitochondrial dysfunction contributing to disease endotype

• Text
• PDF

Abstract

Skin inflammation in juvenile dermatomyositis (JDM) can signal disease onset or flare, and the persistence of cutaneous disease can prevent complete disease remission. The non-invasive study of cutaneous expression signatures through tape stripping (TS) holds the potential to reveal mechanisms underlying disease heterogeneity and organ-specific inflammation. The objectives of this study were to 1) define TS expression signatures in lesional and non-lesional JDM skin, 2) analyze TS signatures to identify JDM disease endotypes and 3) compare TS and blood signatures. While JDM lesional skin demonstrated interferon signaling as the top upregulated pathway, non-lesional skin uniquely highlighted pathways involved in metabolism, angiogenesis and calcium signaling. Both lesional and non-lesional skin shared inflammasome pathway dysregulation. Using unsupervised clustering of skin expression data, we identified a treatment-refractory JDM subgroup distinguished by upregulation of genes associated with mitochondrial dysfunction. The treatment-refractory JDM subgroup also demonstrated higher interferon, angiogenesis and innate immune expression scores in skin and blood, although scores were more pronounced in skin as compared to blood. Tape-stripping expression signatures in JDM provided insight into disease mechanisms and molecular subgroups. Skin, as compared to blood, transcriptional profiles served as more sensitive markers to classify disease subgroups and identify candidate treatment targets.

Authors

Jessica L. Turnier, Sarah M.H. Vandenbergen, Madison E. McClune, Christine Goudsmit, Sophia Matossian, Meredith Riebschleger, Nadine Saad, Jacqueline A. Madison, Smriti Mohan, Johann E. Gudjonsson, Lam C. Tsoi, Celine C. Berthier, J. Michelle Kahlenberg

SPP1^hi macrophages, NKG7 T cells, CCL5^hi fibroblasts, and IgM plasma cells are dominant features of necrobiosis

• Text
• PDF

Abstract

Necrobiosis is a histologic term used to describe abnormal deposits of “degenerating” collagen within the skin. It can be found as an incidental finding in various granulomatous conditions, but is a hallmark of necrobiosis lipoidica (NL) and necrobiotic xanthogranuloma (NXG). There is limited prior research on necrobiosis. Here, we employed single-cell analysis of lesional and nonlesional skin to study the pathophysiology of necrobiosis. Our findings demonstrate that necrobiotic lesional skin is characterized by SPP1hi macrophages expressing MARCO; NKG7-expressing effector CD8+ T cells coexpressing CCL5, IFNG, GZMs, and PRF1; CCL5hi fibroblasts coexpressing CXCL9, diverse collagens (e.g., COL4A4, COL11A1, COL8A1), and TIMP1; and IGHM-expressing plasma cells. Integrative analysis of signaling ligands and receptor expression identified strong cell-cell communication between NKG7+ T cells, CCL5hi fibroblasts, and SPP1-expressing macrophages. In contrast, these cell populations were not dominant features of systemic sclerosis, another collagen deposition disease. Furthermore, although SPP1-expressing macrophages were detectable in sarcoidosis, IFNG-expressing T cells were a more defining feature of sarcoidosis compared with NL and NXG. From these findings, we speculate that necrobiosis results from the deposition of diverse collagens and ECM proteins through a process driven by CCL5-expressing fibroblasts and SPP1-expressing macrophages.

Authors

Stephanie T. Le, Alina I. Marusina, Alexander A. Merleev, Amanda Kirane, Olga Kruglinskaya, Andrey Kunitsyn, Nikolay Yu Kuzminykh, Xianying Xing, Sophie Y. Li, William Liakos, J. Michelle Kahlenberg, Andrea Gompers, Lauren Downing, Sahiti Marella, Allison C. Billi, Paul W. Harms, Lam C. Tsoi, Marie-Charlotte Brüggen, Iannis E. Adamopoulos, Johann E. Gudjonsson, Emanual Maverakis

PKM2-mediated collagen XVII expression is critical for wound repair

• Text
• PDF

Abstract

Chronic wounds have emerged as a tough clinical challenge. An improved understanding of wound healing mechanisms is paramount. Collagen XVII (COL17), a pivotal constituent of hemidesmosomes, holds considerable promise for regulating epidermal cell adhesion to the basement membrane, as well as for epidermal cell motility and self-renewal of epidermal stem cells. However, the precise role of COL17 in wound repair remains elusive, and the upstream regulatory mechanisms involved have not been fully elucidated. In this study, we delineated the temporal and spatial expression patterns of COL17 at the epidermal wound edge. Subsequently, we investigated the indispensable role of COL17 in keratinocyte activation and re-epithelialization during wound healing, demonstrating the restoration of the normal repair process by COL17 overexpression in diabetic wounds. Notably, we identified a key transcriptional signaling pathway for COL17, wherein PKM2 (Pyruvate kinase isozyme M2) promotes phosphorylation of STAT3, leading to its activation and subsequent induction of COL17 expression upon injury. Ultimately, by manipulating this pathway using the PKM2 nuclear translocator SAICAR, we revealed a promising therapeutic strategy for enhancing the healing of chronic wounds.

Authors

Yangdan Liu, Chia-kang Ho, Dongsheng Wen, Jiaming Sun, Yuxin Liu, Qing-Feng Li, Yifan Zhang, Ya Gao

Mindin/spondin-2 regulates fibroblast subpopulations through distinct Src family kinases during fibrogenesis

• Text
• PDF

Abstract

Fibrosis results from excessive extracellular matrix (ECM) deposition, causing tissue stiffening and organ dysfunction. Activated fibroblasts, central to fibrosis, exhibit increased migration, proliferation, contraction, and ECM production. However, it remains unclear if the same fibroblast performs all of the processes that fall under the umbrella term of "activation". Due to fibroblast heterogeneity in connective tissues, subpopulations with specific functions may operate under distinct regulatory controls. Using a transgenic mouse model of skin fibrosis, we found that Mindin (spondin-2), secreted by Snail transgenic keratinocytes, differentially regulates fibroblast subpopulations. Mindin promotes migration and inflammatory gene expression in SCA1+ dermal fibroblasts via Fyn kinase. In contrast, it enhances contractility and collagen production in papillary CD26+ fibroblasts through c-Src signalling. Moreover, in the context of the fibrotic microenvironment of the tumour stroma, we found that differential responses of resident fibroblasts subpopulations to Mindin extend to the generation of functionally heterogeneous cancer-associated fibroblasts (CAFs). This study unveils Mindin as a key orchestrator of dermal fibroblast heterogeneity, reshaping cellular dynamics and signalling diversity in the complex landscapes of skin fibrosis and cancer.

Authors

Sunny Kataria, Isha Rana, Krithika Badarinath, Rania F. Zaarour, Gaurav Kansagara, Sultan Ahmed, Abrar Rizvi, Dyuti Saha, Binita Dam, Abhik Dutta, Ravindra K. Zirmire, Edries Yousaf Hajam, Pankaj Kumar, Akash Gulyani, Colin Jamora

Reprogramming of epidermal keratinocytes by PITX1 transforms the cutaneous cellular landscape and promotes wound healing

• Text
• PDF

Abstract

Cutaneous wound healing is a slow process that often terminates with permanent scarring while oral wounds, in contrast, regenerate damage faster. Unique molecular networks in epidermal and oral epithelial keratinocytes contribute to the tissue-specific response to wounding, but key factors that establish those networks and how the keratinocytes interact with their cellular environment remain to be elucidated. The transcription factor PITX1 is highly expressed in the oral epithelium but is undetectable in cutaneous keratinocytes. To delineate if PITX1 contributes to oral keratinocyte identity, cell-cell interactions, and the improved wound healing capabilities, we ectopically expressed PITX1 in the epidermis of murine skin. Using comparative analysis of murine skin and oral (buccal) mucosa with scRNA-seq and spatial transcriptomics, we found that PITX1 expression enhances epidermal keratinocyte migration, proliferation, and alters differentiation to a quasi-oral keratinocyte state. PITX1+ keratinocytes reprogram intercellular communication between skin-resident cells to mirror buccal tissue while also stimulating the influx of neutrophils that establish a pro-inflammatory environment. Furthermore, PITX1+ skin heals significantly faster than control skin via increased keratinocyte activation and migration and a tunable inflammatory environment. These results illustrate that PITX1 programs oral keratinocyte identity and cellular interactions while also revealing critical downstream networks that promote wound closure.

Authors

Andrew M. Overmiller, Akihiko Uchiyama, Emma D. Hope, Subhashree Nayak, Christopher G. O'Neill, Kowser Hasneen, Yi-Wen Chen, Faiza Naz, Stefania Dell'Orso, Stephen R. Brooks, Kan Jiang, Maria I. Morasso.

ERK hyperactivation in epidermal keratinocytes impairs intercellular adhesion and drives Grover disease pathology

• Text
• PDF

Abstract

Grover disease is an acquired epidermal blistering disorder in which keratinocytes lose intercellular connections. While its pathologic features are well-defined, its etiology remains unclear and it lacks any FDA-approved therapy. Interestingly, Grover disease was a common adverse event in clinical trials for cancer using B-RAF inhibitors, but it remained unknown how B-RAF blockade compromised skin integrity. Here we identified ERK hyperactivation as a key driver of Grover disease pathology. We leveraged a fluorescent biosensor to confirm that B-RAF inhibitors, dabrafenib and vemurafenib, paradoxically activated ERK in human keratinocytes and organotypic epidermis, disrupting cell-cell junctions and weakening epithelial integrity. Consistent with clinical data showing that concomitant MEK blockade prevents Grover disease in patients receiving B-RAF inhibitors, we found that MEK inhibition suppressed ERK and rescued cohesion of B-RAF-inhibited keratinocytes. Validating these results, we demonstrated ERK hyperactivation in patient biopsies from vemurafenib-induced Grover disease, but also from spontaneous Grover disease, revealing a common etiology for both. Finally, in line with our recent identification of ERK hyperactivation in Darier disease, a genetic disorder with identical pathology to Grover disease, our studies uncovered that the pathogenic mechanisms of these two diseases converge on ERK signaling and support MEK inhibition as a therapeutic strategy.

Authors

Cory L. Simpson, Afua Tiwaa, Shivam A. Zaver, Christopher J. Johnson, Emily Y. Chu, Paul W. Harms, Johann E. Gudjonsson

CXCL9, CXCL10, and CCL19 synergistically recruit T-lymphocytes to skin in lichen planus

• Text
• PDF

Abstract

Lichen planus (LP) is a chronic, debilitating, inflammatory disease of the skin and mucous membranes that affects 1% to 2% of Americans. Its molecular pathogenesis remains poorly understood, and there are no FDA-approved treatments. We performed single cell RNA sequencing on paired blood and skin samples (lesional and non-lesional tissue) from 7 LP patients. We discovered that LP keratinocytes and fibroblasts specifically secrete a combination of CXCL9, CXCL10, and CCL19 cytokines. Using an in vitro migration assay with primary human T cells, we demonstrated that CCL19 in combination with either cytokine synergistically enhanced recruitment of CD8 T cells, more than the sum of individual cytokines. Moreover, exhausted T cells in lesional LP skin secreted CXCL13, which along with CCL19 also enhanced recruitment of T cells, suggesting a feed-forward loop in LP. Finally, LP blood revealed decreased circulating naïve CD8 T cells compared to healthy volunteers, consistent with recruitment to skin. Molecular analysis of LP skin and blood samples increased our understanding of disease pathogenesis and identified CCL19 as a new therapeutic target for treatment.

Authors

Anna E. Kersh, Satish Sati, Jianhe Huang, Christina Murphy, Olivia C. Ahart, Thomas H. Leung

Psoriatic arthritis subtypes are phenocopied in humanized mice

• Text
• PDF

Abstract

Psoriatic arthritis (PsA) is a complex inflammatory disease that challenges diagnosis and complicates the rational selection of effective therapies. Although T cells are considered active effectors in psoriasis and PsA, the role of CD8+ T cells in pathogenesis is not well understood. We selected the humanized mouse model NSG-SGM3 transgenic strain to examine psoriasis and PsA endotypes. Injection of PBMCs and sera from patients with psoriasis and PsA generated parallel skin and joint phenotypes in the recipient mouse. The transfer of human circulating memory T cells was followed by migration and accumulation in the skin and synovia of these immunodeficient mice. Unexpectedly, immunoglobulins were required for recapitulation of the clinical phenotype of psoriasiform lesions and PsA domains (dactylitis, enthesitis, bone erosion). Human CD8+ T cells expressing T-bet, IL-32 and CXCL14 were detected by spatial transcriptomics in murine synovia and by immunofluorescence in the human PsA synovia. Importantly, depletion of human CD8+ T cells prevented skin and synovial inflammation in mice humanized with PsA peripheral blood cells. The humanized model of psoriasis and PsA represents a valid platform for accelerating the understanding of disease pathogenesis, improving the design of personalized therapies, and revealing psoriatic disease targets.

Authors

Christopher T. Ritchlin, Javier Rangel-Moreno, Delaney Martino, Brian Isett, Ananta Paine, Soumyaroop Bhattacharya, Jeffrey Fox, Ernest M. Meyer, Riyue Bao, Tullia Bruno, Francisco Tausk, Maria de la Luz Garcia-Hernandez

ADAM17 variant causes hair loss via ubiquitin ligase TRIM47 mediated degradation

• Text
• PDF

Abstract

Hypotrichosis is a genetic disorder which characterized by a diffuse and progressive loss of scalp and/or body hair. Nonetheless, the causative genes for several affected individuals remain elusive, and the underlying mechanisms have yet to be fully elucidated. Here, we discovered a dominant variant in ADAM17 gene caused hypotrichosis with woolly hair. Adam17 (p.D647N) knock-in mice model mimicked the hair abnormality in patients. ADAM17 (p.D647N) mutation led to hair follicle stem cells (HFSCs) exhaustion and caused abnormal hair follicles, ultimately resulting in alopecia. Mechanistic studies revealed that ADAM17 binds directly to E3 ubiquitin ligase TRIM47. ADAM17 (p.D647N) variant enhanced the association between ADAM17 and TRIM47, leading to an increase in ubiquitination and subsequent degradation of ADAM17 protein. Furthermore, reduced ADAM17 protein expression affected Notch signaling pathway, impairing the activation, proliferation, and differentiation of HFSCs during hair follicle regeneration. Overexpression of NICD rescued the reduced proliferation ability caused by Adam17 variant in primary fibroblast cells.

Authors

Xiaoxiao Wang, Chaolan Pan, Luyao Zheng, Jianbo Wang, Quan Zou, Peiyi Sun, Kaili Zhou, Anqi Zhao, Qiaoyu Cao, Wei He, Yumeng Wang, Ruhong Cheng, Zhirong Yao, Si Zhang, Hui Zhang, Ming Li

Distinct T cell signatures are associated with Staphylococcus aureus skin infection in pediatric atopic dermatitis

• Text
• PDF

Abstract

Atopic dermatitis (AD) is an inflammatory skin condition with a childhood prevalence of up to 25%. Microbial dysbiosis is characteristic of AD, with Staphylococcus aureus the most frequent pathogen associated with disease flares and increasingly implicated in disease pathogenesis. Therapeutics to mitigate the effects of S. aureus have had limited efficacy and S. aureus–associated temporal disease flares are synonymous with AD. An alternative approach is an anti–S. aureus vaccine, tailored to AD. Experimental vaccines have highlighted the importance of T cells in conferring protective anti–S. aureus responses; however, correlates of T cell immunity against S. aureus in AD have not been identified. We identify a systemic and cutaneous immunological signature associated with S. aureus skin infection (ADS.aureus) in a pediatric AD cohort, using a combined Bayesian multinomial analysis. ADS.aureus was most highly associated with elevated cutaneous chemokines IP10 and TARC, which preferentially direct Th1 and Th2 cells to skin. Systemic CD4+ and CD8+ T cells, except for Th2 cells, were suppressed in ADS.aureus, particularly circulating Th1, memory IL-10+ T cells, and skin-homing memory Th17 cells. Systemic γδ T cell expansion in ADS.aureus was also observed. This study suggests that augmentation of protective T cell subsets is a potential therapeutic strategy in the management of S. aureus in AD.

Authors

Julianne Clowry, Daniel J. Dempsey, Tracey J. Claxton, Aisling M. Towell, Mary B. Turley, Martin Sutton, Joan A. Geoghegan, Sanja Kezic, Ivone Jakasa, Arthur White, Alan D. Irvine, Rachel M. McLoughlin