In this issue, Zaver et al. report on MEK as a therapeutic target for restoring intercellular adhesion among epidermal keratinocytes and potentially reducing skin blistering in Darier disease. The cover image displays normal human skin stained to highlight proteins critical for epidermal integrity, including the desmosomal cadherin desmoglein 1 (yellow), which is linked to the keratin 10 cytoskeleton (magenta). Nuclei are stained with DAPI (cyan).
New medicines are urgently required to treat the fatal neuromuscular disease, Duchenne muscular dystrophy (DMD). Dimethyl fumarate (DMF) is a potent immunomodulatory small molecule nuclear erythroid 2-related factor 2 (Nrf2) activator with current clinical utility in the treatment of multiple sclerosis and psoriasis that could be effective for DMD and rapidly translatable. Here, we tested two weeks of daily 100mg/kg DMF versus 5mg/kg standard care prednisone (PRED) treatment in juvenile mdx mice with early symptomatic DMD. Both drugs modulated seed genes driving the DMD disease program and improved force production in fast-twitch muscle. However, only DMF showed pro-mitochondrial effects, protected contracting muscles from fatigue, improved histopathology and augmented clinically compatible muscle function tests. DMF may be a more selective modulator of the DMD disease program than PRED warranting follow-up longitudinal studies to evaluate disease modifying impact.
Cara A. Timpani, Stephanie Kourakis, Danielle A. Debruin, Dean G. Campelj, Nancy Pompeani, Narges Dargahi, Angelo Patrick R. Bautista, Ryan M. Bagaric, Elya J. Ritenis, Lauren Sahakian, Didier Debrincat, Nicole Stupka, Patricia Hafner, Peter G. Arthur, Jessica R. Terrill, Vasso Apostolopoulos, Judy B. De Haan, Nuri Gueven, Dirk Fischer, Emma Rybalka
Variation in the preservation of β cell function in clinical trials in type 1 diabetes (T1D) has emphasized the need to define biomarkers to predict treatment response. The T1DAL trial targeted T cells with alefacept (LFA-3-Ig) and demonstrated C-peptide preservation in ~30% of new onset T1D subjects. We analyzed islet antigen reactive (IAR) CD4 T cells in PBMC samples collected prior to treatment from alefacept- and placebo-treated subjects using flow cytometry and single cell RNA-sequencing. IAR CD4 T cells at baseline had heterogenous phenotypes. Transcript profiles formed phenotypic clusters of cells along a trajectory based on increasing maturation and activation, and T cell receptor (TCR) chains showed clonal expansion. Notably, the frequency of IAR CD4 T cells with a memory phenotype and a unique transcript profile (Cluster 3) were inversely correlated with C-peptide preservation in alefacept-, but not placebo-treated subjects. Cluster 3 cells had a proinflammatory phenotype characterized by expression of the transcription factor BHLHE40 and the cytokines GM-CSF and TNF-α, and shared TCR chains with effector memory-like clusters. Our results suggest IAR CD4 T cells as a potential baseline biomarker of response to therapies targeting the CD2 pathway and warrant investigation for other T cell-related therapies.
Elisa Balmas, Janice Chen, Alex K. Hu, Hannah A. DeBerg, Mario G. Rosasco, Vivian H. Gersuk, Elisavet Serti, Cate Speake, Carla J. Greenbaum, Gerald T. Nepom, Peter S. Linsley, Karen Cerosaletti
Mucopolysaccharidosis VI (MPS VI) is a rare lysosomal disease arising from impaired function of the enzyme Arylsulfatase B (ARSB). This causes aberrant accumulation of dermatan sulfate, a glycosaminoglycan (GAG) abundant in cartilage. While clinical severity varies along with age at first symptom manifestation, MPS VI usually presents early and strongly affects the skeleton. Current enzyme replacement therapy (ERT) does not provide effective treatment for the skeletal manifestations of MPS VI. This lack of efficacy may be due to inability of ERT to reach affected cells, or irreversibility of disease. To address the question of reversibility of skeletal phenotypes, we generated a conditional by inversion (COIN) mouse model of MPS VI, ArsbCOIN/COIN, wherein Arsb is initially null and can be restored to wild type using Cre. We restored Arsb at different times during postnatal development, using a tamoxifen-dependent global Cre driver. By restoring Arsb at postnatal days 7, 21, and 56-70 (P7, P21, and P56-P70), we determined that skeletal phenotypes can be fully rescued if Arsb restoration occurs at P7, while only achieving partial rescue at P21, and no significant rescue at P56-70. This work has highlighted the importance of early intervention in MPS VI patients to maximize therapeutic impact.
Elizabeth Hwang-Wong, Gabrielle Amar, Nanditha Das, Xiaoli Zhang, Nina A. Aaron, Kirsten Gale, Nyanza J. Rothman, Massimo Fante, Andrew D. Baik, Ajay Bhargava, Arun D. Fricker, Michelle McAlister, Jeremy S. Rabinowitz, John Lees-Shepard, Kalyan Nannuru, Aris N. Economides, Katherine D. Cygnar
Tissue-resident lymphocytes (TRLs) are critical for local protection against viral pathogens in peripheral tissue. However, it is unclear if TRLs perform a similar role in transplanted organs under chronic immunosuppressed conditions. The present study aimed to characterize the TRL compartment in human kidney transplant nephrectomies and examine its potential role in antiviral immunity. The TRL compartment of kidney transplants contained diverse innate(-like) and adaptive TRL populations expressing the canonical residency markers CD69, CD103, and CD49a. Chimerism of donor and recipient cells was present in 43% of kidney transplants and occurred in all TRL subpopulations. Paired single-cell transcriptome and T-cell receptor (TCR) sequencing showed that donor and recipient tissue-resident memory T (TRM) cells exhibit striking similarities in their transcriptomic profiles and share numerous TCR clonotypes predicted to target viral pathogens. Virus dextramer staining further confirmed that CD8 TRM cells of both donor and recipient origin cexpress TCRs with specificities against common viruses, including CMV, EBV, BK polyomavirus, and influenza A. Overall, the study results demonstrate that a diverse population of TRLs resides in kidney transplants and offer compelling evidence that TRM cells of both donor and recipient origin reside within this TRL population and may contribute to local protection against viral pathogens.
Daphne M. Hullegie-Peelen, Hector Tejeda Mora, Dennis A. Hesselink, ERIC M.J. BINDELS, Thierry Paulus Pierre van den Bosch, Marian C. Clahsen-van Groningen, Marjolein Dieterich, Sebastiaan Heidt, Robert C. Minnee, Georges M.G.M. Verjans, Martin J. Hoogduijn, Carla C. Baan
Intratumoral B cell responses are associated with more favorable clinical outcomes in human pancreatic ductal adenocarcinoma (PDAC). However, the antigens driving these B cell responses are largely unknown. We sought to discover these antigens by using single-cell RNA sequencing (scRNA-Seq) and immunoglobulin (Ig) sequencing of tumor-infiltrating immune cells from seven primary PDAC samples. We identified activated T and B cell responses and evidence of germinal center reactions. Ig sequencing identified plasma cell (PC) clones expressing isotype-switched and hyper-mutated Igs, suggesting the occurrence of T cell-dependent B cell responses. We assessed the reactivity of 41 recombinant antibodies that represented the products of 235 PCs and 12 B cells toward multiple cell lines and PDAC tissues, and observed frequent staining of intracellular self-antigens. Three of these antigens were identified: the filamentous actin (F-actin), the nucleic protein, RUVBL2, and the mitochondrial protein, HSPD1. Antibody titers to F-actin and HSPD1 were significantly elevated in the plasma of PDAC patients (n=59) compared to healthy donors (n=61). Thus, PCs in PDAC produce auto-antibodies reacting with intracellular self-antigens, which may result from promotion of pre-existing, autoreactive B cell responses. These observations indicate that the chronic inflammatory microenvironment of PDAC can support the adaptive immune response.
Min Yao, Jonathan Preall, Johannes Yeh, Darryl J. Pappin, Paolo Cifani, Yixin Zhao, Sophia Shen, Philip Moresco, Brian He, Hardik Patel, Amber N. Habowski, Daniel A. King, Kara L. Raphael, Arvind Rishi, Divyesh V. Sejpal, Matthew Weiss, David Tuveson, Douglas T. Fearon
JCI This Month is a digest of the research, reviews, and other features published each month.