Hair follicle epithelial stem cells contribute to interfollicular epidermis during homeostasis
Ghotbi et al. demonstrate that transcription factor KROX20 marks a stem cell population in the hair follicle whose lineages contribute to the interfollicular epidermis. In the cover image, the green spheres within the upper hair follicle region represent KROX20-positive stem cells that migrate up to maintain proper epidermal homeostasis. Image credit: Elnaz Ghotbi, generated using ChatGPT.
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Research Letter
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Abstract
Authors
Sanjna Singh, Célia Fourrier, Kathryn J. Hattersley, Leanne K. Hein, Jemima Gore, Alexis Martin, Linh V.P. Dang, Barbara King, Rachael A. Protzman, Paul J. Trim, Leonie K. Heilbronn, Julien Bensalem, Timothy J. Sargeant
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Review
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Abstract
Long COVID is a debilitating condition that can develop after a SARS-CoV-2 infection and is characterized by a wide range of chronic symptoms, including weakness, neurocognitive impairment, malaise, fatigue, and many others, that affect multiple organ systems. At least 10% of individuals with a previous infection may develop long COVID, which affects their ability to perform daily functions and work. Despite its severity and widespread impact, this multisystemic condition remains poorly understood. Recent studies suggest that dysregulation of the complement system, a key component of the innate immune response, may contribute to the pathogenesis of long COVID, particularly in connection with coagulation, inflammation, and vascular injury. In this Review, we examine the evidence linking complement system dysregulation to long COVID and explore its potential role in driving disease pathology.
Authors
Rafael Bayarri-Olmos, William Bain, Akiko Iwasaki
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Research Articles
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Abstract
Hematopoietic protein-1 (Hem1) is a component of the WASp family verprolin-homologous protein (WAVE) actin regulatory complex, which is activated downstream of multiple immune receptors. Mutations in the NCKAP1L gene encoding HEM1 have recently been found to result in severe primary immunodeficiency disease (PID), characterized by recurrent respiratory infections, hyperinflammation, autoimmunity, and high mortality. However, how loss of Hem1 results in PID is unclear. To define the importance of Hem1 specifically in T cells, we generated constitutive and T cell–specific Hem1-null mice. Hem1-deficient T cells exhibited an increased shift from naive to memory T cells and increased ratio of immunosuppressive regulatory to effector T cells. Loss of Hem1 resulted in hallmarks of T cell exhaustion, including T cell lymphopenia, decreased activation and proliferation, increased expression of PD-1 and Tim3, and increased IL-10 production. In vitro TCR stimulation of CD4+ T cells resulted in increased production of Th1 (IFN-γ), Th2 (IL-5, IL-13), Th17 (IL-17, IL-22), and Treg (IL-10) cytokines. This correlated with reduced F-actin, increased expression of CD107a, and increased granzyme release indicative of increased granule membrane fusion and exocytosis. These results suggest that Hem1 is critical for maintaining T cell activation, homeostasis, and regulated cytokine production following antigen encounter.
Authors
Alexandra Christodoulou, Nutthakarn Suwankitwat, Jacob T. Tietsort, Ryan Culbert, Julia Y. Tsai, Fatima Tarbal, Chengsong Zhu, Brian M. Iritani
×Abstract
Ehlers-Danlos syndromes (EDS) comprise a genetically and clinically heterogenous group of rare diseases that cause severe, often fatal, damage to connective tissue. The molecular basis of EDS implicates defects in extracellular matrix components, including various fibrillar collagens and glycosaminoglycans (GAGs). However, the precise pathogenic mechanisms behind EDS remain elusive. Here, we have implemented a multi-tiered approach to demonstrate the functional impact of B3GALT6 mutations on biochemical and developmental processes, ultimately leading to the spondylodysplastic subtype of EDS (spEDS), characterized by severe musculoskeletal symptoms. We show that the loss of function of β1,3-galactosyltransferase 6 (β3GalT6) is partially compensated by β1,3-glucuronosyltransferase 3 (GlcAT-I), the next enzyme in the GAG biosynthetic pathway. In addition, results from transcriptomics, collagen analysis, and biophysical experiments revealed that impaired collagen maturation, including defective glycosylation of collagen XII, contributes to altered tissue structure and biomechanics, the hallmarks of spEDS. Our findings unravel a new pathogenic mechanism of spEDS and bring us one step closer to therapeutic strategies, including cell and tissue engineering.
Authors
Roméo Milan Diana, Benjamin Jolivet, Jean-Baptiste Vincourt, Sébastien Hergalant, Grégory Francius, Yasaman Karami, Hamed Khakzad, Rebekka Wild, Marie Bourgeais, Anne Robert, Alison Wurtz, Guillermo Barreto, Nick Ramalanjaona, Déborah Helle, Rachel Onifarasoaniaina, Sophie Front, Chrystel Lopin-Bon, Delfien Syx, Fransiska Malfait, Sylvie Fournel-Gigleux, Sandrine Gulberti, Catherine Bui
×Abstract
While the accumulation of tumor-associated macrophages (TAMs) in glioblastoma (GBM) has been well documented, targeting TAMs has thus far yielded limited clinical success in slowing GBM progression due, in part, to an incomplete understanding of TAM function. Using an engineered 3D hydrogel–based model of the brain tumor microenvironment (TME), we show that M2-polarized macrophages stimulate transcriptional and phenotypic changes in GBM stem cells (GSCs) closely associated with the highly aggressive and invasive mesenchymal subtype. By combining proteomics with GBM patient single-cell transcriptomics, we identify multiple TAM-secreted proteins with putative proinvasive functions and validate TGF-β induced (TGFBI, also known as BIGH3) as a targetable TAM-secreted tumorigenic factor. Our work highlights the utility of coupling multiomics analyses with engineered TME models to investigate TAM–cancer cell crosstalk and offers insights into TAM function to guide TAM-targeting therapies.
Authors
Erin A. Akins, Dana Wilkins, Zaki Abou-Mrad, Kelsey Hopland, Robert C. Osorio, Kenny K.H. Yu, Manish K. Aghi, Sanjay Kumar
×Abstract
Uracil DNA glycosylase (UNG) excises uracil and 5-fluorouracil bases from DNA and is implicated in fluorodeoxyuridine (FdU) resistance. Here we explore the effects of inhibiting UNG activity, or depleting the UNG protein, in 2 mouse syngeneic models for colorectal cancer. Overexpressing the small UNG inhibitor protein (UGI) in mismatch repair–deficient (MMR-deficient) MC38 cells injected into C57BL/6J mice delayed tumor growth and prolonged survival when combined with FdU. Combining UNG inhibition with FdU numerically increased CD4+ T lymphocytes and B cells compared with FdU or UNG inhibition alone, suggesting an immune component to the effects. In contrast, shRNA depletion of UNG in the absence of FdU treatment resulted in 70% of mice clearing their tumors, and a 3-fold increase in overall survival compared with FdU. Analysis of MC38 tumor–infiltrating immune cells showed UNG depletion increased monocyte and dendritic cell populations, with CD8+ T cells also numerically increased. shRNA depletion of UNG in MMR-proficient CT-26 cells injected into BALB/c mice produced minimal benefit; the addition of anti–PD-1 antibody synergized with UNG depletion to increase survival. Cytotoxic T cell depletion abolished the benefits of UNG depletion in both models. These findings suggest UNG inhibition and/or depletion could enhance antitumor immune responses in humans.
Authors
Eric S. Christenson, Brandon E. Smith, Thanh J. Nguyen, Alens Valentin, Soren Charmsaz, Nicole E. Gross, Sarah M. Shin, Alexei Hernandez, Won Jin Ho, Srinivasan Yegnasubramanian, James T. Stivers
×Abstract
Cancer-associated fibroblasts (CAFs) are part of the tumor microenvironment (TME) that enable cancer cells to establish metastases, but the mechanisms of these interactions are not fully known. Herein, we identified a paracrine mechanism in which CAF-secreted asporin (ASPN) activated ErbB signaling and subsequent migration of adjacent prostate cancer cells. Our data support that ASPN bound directly to the ligand binding domain of human epidermal growth factor 3 (HER3) and induced HER2/HER3 heterodimerization and activation of the PI3K, MAPK, and calcium pathways. Genetic and therapeutic inhibition of HER2/HER3 ablated ASPN-induced signaling and migration. Clinically, ASPN was detected in the stroma of HER2/HER3-expressing human metastatic prostate cancer, supporting the clinical relevance of these findings and highlighting a potential therapeutic vulnerability. Antibody-drug conjugate (ADC) therapies designed to target HER2 (trastuzumab-deruxtecan) or HER3 (patritumab-deruxtecan) significantly diminished prostate cancer cell growth in vitro and tumor size in vivo, despite Aspn in the TME. Collectively, these findings indicate ASPN functions as a HER3 ligand to induce cellular migration, and inhibition with anti-HER2 or anti-HER3 ADC therapies highlights potential clinical utility for patients with metastatic castration-resistant prostate cancer that expresses HER2 or HER3.
Authors
Amanda B. Hesterberg, Hong Yuen Wong, Jorgen Jackson, Monika Antunovic, Brenda L. Rios, Evan Watkins, Riley E. Bergman, Brad A. Davidson, Sarah E. Ginther, Diana Graves, Elliott F. Nahmias, Jared A. Googel, Lillian B. Martin, Violeta Sanchez, Paula I. Gonzalez-Ericsson, Quanhu Sheng, Benjamin P. Brown, Jens Meiler, Kerry R. Schaffer, Jennifer B. Gordetsky, Ben H. Park, Paula J. Hurley
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T cells rely on different metabolic pathways to differentiate into effector or memory cells, and metabolic intervention is a promising strategy to optimize T cell function for immunotherapy. Pyruvate dehydrogenase (PDH) is a nexus between glycolytic and mitochondrial metabolism, regulating pyruvate conversion to either lactate or acetyl-CoA. Here, we retrovirally transduced pyruvate dehydrogenase kinase 1 (PDK1) or pyruvate dehydrogenase phosphatase 1 (PDP1), which control PDH activity, into CD8+ T cells to test effects on T cell function. Although PDK1 and PDP1 were expected to influence PDH in opposing directions, by several criteria they induced similar changes relative to control T cells. Seahorse metabolic flux assays showed both groups exhibited increased glycolysis and oxidative phosphorylation. Both groups had improved primary and memory recall responses following infection with murine gammaherpesvirus-68. However, metabolomics using labeled fuels indicated differential usage of key fuels by metabolic pathways. Importantly, CD8+ T cell populations after B cell lymphoma challenge were smaller in both groups, resulting in poorer protection, which was rescued by glutamine and acetate supplementation. Overall, this study indicates that PDK1 and PDP1 both enhance metabolic capacity, but the context of the antigenic challenge significantly influences the consequences for T cell function.
Authors
Taewook Kang, Young-Kwang Usherwood, Julie A. Reisz, Sukrut C. Kamerkar, Rachel Culp-Hill, Owen M. Wilkins, Andreia F. Verissimo, Fred W. Kolling IV, Anton M. Hung, Shawn C. Musial, Pamela C. Rosato, Angelo D’Alessandro, Henry N. Higgs, Edward J. Usherwood
×Chronic integrated stress response causes dysregulated cholesterol synthesis in white matter disease
Abstract
Maladaptive integrated stress response (ISR) activation is observed in human diseases of the brain. Genetic mutations of eIF2B, a critical mediator of protein synthesis, cause chronic pathway activation resulting in a leukodystrophy, but the precise mechanism is unknown. We generated N208Y eIF2B-α mice and found that this metabolite binding mutation led to destabilization of eIF2B-α, a systemic ISR, and neonatal lethality. 2BAct, an eIF2B activator, rescued lethality and significantly extended the lifespan of this severe model, underscoring its therapeutic potential in pediatric disease. Continuous treatment was required for survival, as withdrawal led to ISR induction in all tissues and rapid deterioration, thereby providing a model to assess the impact of the ISR in vivo by tuning drug availability. Single nuclei RNA-seq of the CNS identified astrocytes, oligodendrocytes, and ependymal cells as the cell types most susceptible to eIF2B dysfunction and revealed dysfunctional maturation of oligodendrocytes. Moreover, ISR activation decreased cholesterol biosynthesis, a process critical for myelin formation and maintenance. As such, persistent ISR engagement may contribute to pathology in other demyelinating diseases.
Authors
Karin Lin, Nina Ly, Rejani B. Kunjamma, Ngoc Vu, Bryan King, Holly M. Robb, Eric G. Mohler, Janani Sridar, Qi Hao, José Zavala-Solorio, Chunlian Zhang, Varahram Shahryari, Nick van Bruggen, Caitlin F. Connelly, Bryson D. Bennett, James J. Lee, Carmela Sidrauski
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We assessed the therapeutic efficacy of a semiallogeneic dendritic cell (DC) vaccine in comparison to a syngeneic one for suppression of B16-F10 and TC-1 tumors. Syngeneic bone marrow–derived DCs (BMDCs) were generated from C57BL/6J mice and semiallogeneic BMDCs with a mutation in either MHC class I or II were generated from B6.C-H2-Kbm1/ByJ or B6(C)-H2-Ab1bm12/KhEgJ mice, respectively. We demonstrated in vivo and in vitro that the MHC class II semiallogeneic BMDC vaccine had superior efficacy over the syngeneic and the MHC class I semiallogeneic BMDC vaccine, providing allogeneic CD4+ T cell help to enhance the antitumor CD8+ T cell response through allogeneic stimulation by the mutant MHC class II molecules. We discovered that this help was induced only at an early stage of tumor growth and at a later stage of tumor growth; combining our BMDC vaccine with Treg depletion enhanced tumor suppression. We demonstrated the improved efficacy of a semiallogeneic BMDC vaccine that kept tumor-peptide presentation intact on syngeneic MHC class I molecules so that mutant MHC class II could provide allogeneic help. This strategy should enable promising new DC-based cancer immunotherapies, offering an alternative to autologous DC vaccines by incorporating allogenicity as an adjuvant.
Authors
Noriko Seishima, William Becker, Purevdorj B. Olkhanud, Hoyoung M. Maeng, Miguel A. Lopez-Lago, William V. Williams, Jay A. Berzofsky
×Abstract
Acute kidney injury (AKI) is characterized by a rapid decline in renal function. In severe or recurrent cases, AKI can progress to chronic kidney disease (CKD), marked by renal inflammation and fibrosis. Despite the severity of these outcomes, early-stage diagnostic tools and pharmacological interventions for AKI-to-CKD progression remain limited. In this study, we examined circular RNA (circRNA) expression profiles in mouse renal cortex tissues 14 days after ischemia/reperfusion (I/R) injury using circRNA-Seq. The renal biopsy samples of patients after AKI exhibited reduced CircNSD1 expression, which was inversely associated with inflammation and fibrosis. Overexpression of CircNSD1 attenuated ferroptosis in vivo and in vitro, while slowing AKI-to-CKD progression. Mechanistically, CircNSD1 downregulated ACSL4 and SLC39A14 expression through histone H3 lysine 36 (H3K36) methylation, a critical pathway regulating ferroptosis after AKI or hypoxia/reoxygenation (H/R) injury. Furthermore, we identified that CircNSD1 encoded a NSD1-916aa peptide, which may functionally contribute to its observed effect. Collectively, these findings demonstrated that CircNSD1 may serve as a diagnostic and therapeutic target for early detection of AKI-to-CKD transition.
Authors
Li Gao, Junsheng Zhang, Chaoyi Chen, Sai Zhu, Xianglong Wei, Guiqin Tang, Sheng Wang, Yukai Wang, Xinran Liu, Ling Jiang, Yonggui Wu
×Abstract
Nonresolving inflammation and maladaptive renal repair contribute to the pathogenesis of acute kidney injury (AKI) transition to chronic kidney disease (CKD). Few therapies have been identified that can modulate these injurious pathways following AKI. Spleen tyrosine kinase (SYK) is an immune regulator expressed in the kidney and a potential therapeutic target for AKI. The effect of the selective SYK inhibitor entospletinib was studied in AKI-to-CKD transition. Entospletinib was administered to mice undergoing unilateral renal ischemia-reperfusion injury (IRI), with kidneys analyzed over 14 days. Single-cell RNA sequencing, digital spatial profiling, intravital microscopy, and flow cytometry were employed to study renal phenotypes. Entospletinib administered before and after IRI protected ischemic kidneys and significantly attenuated the transition to CKD. Entospletinib targeted leukocyte-expressed SYK and prevented neutrophil/monocyte recruitment to the kidney. Entospletinib reduced nonresolving tubulointerstitial inflammation after AKI by blocking activation of mannose receptor-1– and C-type lectin domain family 7 member A–expressing proinflammatory macrophages. The resolution of renal inflammation mediated by entospletinib was associated with a reciprocal increase in resident macrophages, reparative gene expression, preserved tubular integrity, and reduced renal fibrosis. The SYK inhibitor entospletinib resolves renal inflammation and promotes repair following AKI.
Authors
Esteban E. Elias, Arthur Lau, Sisay Getie Belay, Afshin Derakhshani, Graciela Andonegui, Craig N. Jenne, Antoine Dufour, Nathan A. Bracey, Justin Chun, Daniel A. Muruve
×Abstract
Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease with no effective pharmacological interventions. While single-cell transcriptomics has advanced our understanding of AAA, it lacks spatial context. Here, we employed Seq-Scope, an ultra-high-resolution spatial transcriptomic technology, to decipher the spatial landscape of angiotensin II–induced AAA in Apoe–/– mice. Our analysis revealed the heterogeneity of macrophages, fibroblasts, and smooth muscle cells (SMCs), with specific responses in different layers of the AAA tissue. SMCs in the inner layers showed associations with Mgp-expressing fibroblasts and GPNMB-expressing macrophages, whereas the outer layers had different dominant cell types. Notably, GPNMB-expressing macrophages were concentrated near SMCs in regions of severe elastic lamina damage. Immunofluorescent staining confirmed their colocalization, and scRNA-seq reanalysis independently validated the presence of GPNMB-high macrophages in AAA tissues, highlighting their involvement in inflammation and tissue remodeling. Moreover, we discovered that macrophage-derived soluble GPNMB induces SMC phenotypic switching, reducing contractile markers while increasing cytokines and metalloproteinases. This effect was partly mediated by CD44 signaling. These findings suggest that GPNMB-high macrophages contribute to AAA development by driving SMC dysfunction. This study highlights the importance of high-resolution spatial transcriptomics in complementing single-cell transcriptomics, offering valuable insights into molecular and cellular responses in the AAA microenvironment.
Authors
Guizhen Zhao, Chun-Seok Cho, Hongyu Liu, Yongha Hwang, Yichen Si, Myungjin Kim, Yongjie Deng, Yang Zhao, Chao Xue, Yanhong Guo, Lin Chang, Dogukan Mizrak, Bo Yang, Hyun Min Kang, Jifeng Zhang, Jun Hee Lee, Y. Eugene Chen
×Abstract
The tumor microenvironment (TME) is highly heterogeneous and can dictate the success of therapeutic interventions. Identifying TMEs that are susceptible to specific therapeutic interventions paves the way for more personalized and effective treatments. In this study, using a spontaneous murine model of breast cancer, we characterize a TME that is responsive to inhibitors of the heme degradation pathway mediated by heme oxygenase (HO), resulting in CD8+ T cell– and NK cell–dependent tumor control. A hallmark of this TME is a chronic type I interferon (IFN) signal that is directly involved in orchestrating the antitumor immune response. Importantly, we identify that similar TMEs exist in human breast cancer that are associated with patient prognosis. Leveraging these observations, we demonstrate that combining a STING agonist, which induces type I IFN responses, with an HO inhibitor produces a synergistic effect leading to superior tumor control. This study highlights HO activity as a potential resistance mechanism for type I IFN responses in cancer, supporting a therapeutic rationale for targeting the heme degradation pathway to enhance the efficacy of STING agonists.
Authors
Dominika Sosnowska, Tik Shing Cheung, Jit Sarkar, James W. Opzoomer, Karen T. Feehan, Joanne E. Anstee, Chloé A. Woodman, Mohamed Reda Keddar, Kalum Clayton, Samira Ali, William Macmorland, Dorothy D. Yang, James Rosekilly, Cheryl E. Gillett, Francesca D. Ciccarelli, Richard Buus, James Spicer, Anita Grigoriadis, James N. Arnold
×Abstract
Parathyroid hormone (PTH) regulates serum calcium and phosphate through its actions in bone and kidney and is used to increase bone in osteoporosis treatment. In bone, PTH targets osteoblasts and osteocytes to regulate bone remodeling but also bone marrow stromal cells (BMSCs), regulating their differentiation in the osteoblast or the adipocyte lineage. PTH exerts its action through the PTH/PTH-related peptide (PTHrP) receptor, a G protein–coupled receptor (GPCR), activating adenylyl cyclase and phospholipase C (PLC). Although the effects of cAMP and PKA are well characterized, little is known about the effects of PLC activation or on the crosstalk between PTH signaling and other pathways. Here, bulk RNA-Seq of PTH-treated murine BMSC line (W-20) revealed significant changes in the Hippo pathway. In addition to increasing its transcription, PTH stabilized YAP protein, a key target of Hippo, by decreasing YAP/LArge Tumor Suppressor kinase 1 (LATS1) interaction, YAPS127 phosphorylation, and YAP ubiquitination, leading to YAP nuclear translocation and expression of YAP target genes. Similar events occurred in osteocyte cell lines. This occurred via an increase in Src kinase activity: We identified YAPY428 as a key tyrosine residue phosphorylated by Src in response to PTH. Preventing YAPY428 phosphorylation led to YAP instability, blocking both osteogenic and adipogenic differentiation of W-20 cells. These results demonstrate active crosstalk between the PTH/PTHrP and the Hippo signaling pathways and reveal that PTH signaling utilizes the PLC/Ca2+/Src tyrosine kinase signaling cascade to influence YAP stability, antagonizing Hippo signaling and favoring stromal cell differentiation. Thus, PTH signaling counteracts the effects of Hippo signaling in BMSCs to favor their differentiation.
Authors
Sara Monaci, Mengrui Wu, Hiroyuki Okada, Kedkanya Mesil, Byeong-Rak Keum, Maisa Monseff Rodrigues da Silva, Clifford J. Rosen, Francesca Gori, Roland Baron
×Abstract
Epilepsy is a common neurological disorder resulting from an imbalance between neuronal excitation and inhibition. Synapses play a pivotal role in the pathogenesis of epilepsy. Src-homology 2 (SH2) domain–containing protein 5 (SH2D5) is highly expressed in the brain and is implicated in the regulation of synaptic function. However, its role and mechanism in epilepsy remain unclear. In this study, we found that SH2D5 was predominantly localized to pyramidal neurons in the mouse hippocampus and was upregulated in the hippocampus of epileptic brains. KO of Sh2d5 in the hippocampus alleviated both the susceptibility to and severity of epileptic activity. Mechanistically, SH2D5 regulated N-methyl-D-aspartate receptor–mediated (NMDAR–mediated) excitatory synaptic transmission by altering the protein expression levels of NMDAR subunits. We further demonstrated that SH2D5 modulated the transcription of NMDARs by promoting the autophagic degradation of STAT1. These findings suggest that targeting the SH2D5/STAT1/NMDAR pathway may offer a potential therapeutic strategy for epilepsy.
Authors
Haokun Guo, Hui Zhang, Chenlu Zhang, Yuanyuan Shen, Liumi Jiang, Min Yang, Yuansong Zhang, Ningning Zhang, Ruirui Zhang, Ran Yu, Yong Yang, Xin Tian
×Abstract
Yellow fever virus (YFV) infection is fatal in 5%–10% of the 200,000 yearly cases. There is currently no available antiviral treatment. We showed previously that administration of 50 mg/kg of a YFV-specific neutralizing monoclonal antibody (nmAb) at 2 days postinfection (dpi), prior to the onset of severe disease, protected YFV-infected rhesus macaques from death. To further explore the clinical applicability of our nmAb MBL-YFV-01, we treated rhesus macaques with a lower dose (10 mg/kg) of this nmAb prophylactically or therapeutically at 3.5 dpi. We show that a single prophylactic or therapeutic i.v. dose of our nmAb protects rhesus macaques from death following challenge. A comprehensive analysis of 167 inflammatory cytokine and chemokines revealed that protection was associated with significantly reduced expression of 125 of these markers, including type I IFN, IL-6, and CCL2. This study further expands the potential clinical use of our YFV-specific nmAb, which could be used during an outbreak for immediate prophylactic immunity or for patients with measurable serum viremia.
Authors
Lauren N. Rust, Michael J. Ricciardi, Savannah S. Lutz, Sofiya Yusova, Johan J. Louw, Aaron Yrizarry-Medina, Sreya Biswas, Miranda Fischer, Aaron Barber-Axthelm, Gavin Zilverberg, Lauren Bailey, Tonya Swanson, Rachael Tonelli, G.W. McElfresh, Brandon C. Rosen, Thomas B. Voigt, Christakis Panayiotou, Jack T. Mauter, Noor Ghosh, Jenna Meanor, Giovana Godoy, Michael Axthelm, Jeremy Smedley, Mark K. Slifka, Esper G. Kallas, Gabriela Webb, Robert Zweig, Caralyn S. Labriola, Benjamin N. Bimber, Jonah B. Sacha, David I. Watkins, Benjamin J. Burwitz
×Abstract
The aryl hydrocarbon receptor (AhR) is proposed to mediate the frailty-promoting effects of the tryptophan metabolite kynurenine, which increases with age in mice and humans. The goal of the current study was to test whether administration of pharmacological AhR inhibitors, BAY2416964 and CH-223191, could abrogate musculoskeletal decline in aging mice. Female C57BL/6 mice (18 months old) were treated with vehicle (VEH) or 30 mg/kg BAY2416964 (BAY) via daily oral gavage 5 days/week for 8 weeks. A second AhR antagonist, CH-223191, was administered to 16-month-old male and female C57BL/6 mice via intraperitoneal injections (3.3 mg/kg) 3 days/week for 12 weeks. While grip strength declined over time in VEH-treated mice, BAY preserved grip strength in part by improving integrity of neuromuscular junctions (NMJs), an effect replicated during in vitro studies with siRNA against AhR. Cortical bone mass was also greater in BAY- than VEH-treated mice. Similarly, CH-223191 treatment improved cortical bone and showed beneficial effects in skeletal muscle, including reducing oxidative stress as compared with VEH-treated animals. Transcriptomic and proteomic data from BAY-treated mice supported a positive impact of BAY on molecular targets that affect NMJ function. Taken together, these data support AhR as a therapeutic target for improving musculoskeletal health during aging.
Authors
Kanglun Yu, Sagar Vyavahare, Dima Alhamad, Husam Bensreti, Ling Ruan, Anik Tuladhar, Caihong Dai, Joseph C. Shaver, Alok Tripathi, Kehong Ding, Rafal Pacholczyk, Marion A. Cooley, Roger Zhong, Maribeth H. Johnson, Jie Chen, Wendy B. Bollag, Carlos M. Isales, William D. Hill, Mark W. Hamrick, Sadanand Fulzele, Meghan E. McGee-Lawrence
×Abstract
Hereditary cardiomyopathies are the prototypic forms of heart failure and major causes of sudden cardiac death. The genome in cardiomyopathies is exposed to internal stressors, which damage the DNA and activate the DNA damage response (DDR) pathways. We set out to determine whether the DDR pathways were activated and pathogenic in an established mouse model of desmoplakin (DSP) cardiomyopathy generated upon deletion of the Dsp gene in cardiomyocytes (Myh6-MerCreMerTam Dspfl/fl; Myh6-McmTam Dspfl/fl). The mice exhibited premature death, cardiac dysfunction, myocardial cell death, fibrosis, and increased expression levels of the pro-inflammatory cytokines, consistent with the phenotype of human DSP cardiomyopathy. Cytosolic nuclear self-DNA (nDNA) and mitochondrial DNA (mtDNA) were increased in cardiomyocyte cytosol in the Myh6-McmTam Dspfl/fl mice. Likewise, the DDR pathway proteins, including the cyclic GMP-AMP synthase (CGAS)/stimulator of interferon response 1, were upregulated, as were the transcript levels of interferon response factor 3 and the NF-κB target genes. Deletion of the Mb21d1 gene encoding CGAS in the Myh6-McmTam Dspfl/fl mice prolonged survival, improved cardiac function, attenuated fibrosis, and reduced cell death. Thus, cytosolic nDNA and mtDNA are increased and the DDR pathways are activated and pathogenic in a mouse model of DSP cardiomyopathy, whereas genetic blockade of CGAS is salubrious.
Authors
Weiyue Wang, Benjamin Cathcart, Quoc D. Nguyen, Loi Q. Lao, Amelia Bryans, Sara E. Coleman, Leila Rouhi, Priyatansh Gurha, Ali J. Marian
×Abstract
Tumor immunosuppression affects survival and treatment efficacy. Tumor NOS2/COX2 coexpression strongly predicts poor outcome in estrogen receptor–negative (ER–) breast cancer by promoting metastasis, drug resistance, cancer stemness, and immune suppression. Herein, a spatially distinct NOS2/COX2 and CD3+CD8+PD1– T effector (TEff) cell landscape correlated with poor survival in ER– tumors. NOS2 was primarily expressed at the tumor margin, whereas COX2 together with B7H4 was associated with immune desert regions lacking TEff cells, where a higher ratio of tumor NOS2 or COX2 to TEff cells predicted poor survival. Also, programmed cell death ligand 1/programmed cell death 1, regulatory T cells (TRegs), and IDO1 were primarily associated with stroma-restricted TEff cells. Regardless of the survival outcome, CD4+ T cells and macrophages were primarily in stromal lymphoid aggregates. Finally, in a 4T1 model, COX2 inhibition led to increased CD8+ TEff/CD4+ TReg ratio and CD8+ TEff infiltration while Nos2 deficiency had no significant effect, thus reinforcing our observations that COX2 is an essential component of immunosuppression through CD8+ TEff cell exclusion from the tumor. Our study indicates that tumor NOS2/COX2 expression plays a central role in tumor immune evasion, suggesting that strategies combining clinically available NOS2/COX2 inhibitors with immune therapy could provide effective options for the treatment of aggressive and drug-resistant ER– breast tumors.
Authors
Lisa A. Ridnour, Robert Y.S. Cheng, William F. Heinz, Milind Pore, Ana L. Gonzalez, Elise L. Femino, Rebecca L. Moffat, Adelaide L. Wink, Fatima Imtiaz, Leandro L. Coutinho, Donna Butcher, Elijah F. Edmondson, M. Cristina Rangel, Stephen T.C. Wong, Stanley Lipkowitz, Sharon A. Glynn, Michael P. Vitek, Daniel W. McVicar, Xiaoxian Li, Stephen K. Anderson, Nazareno Paolocci, Stephen M. Hewitt, Stefan Ambs, Timothy R. Billiar, Jenny C. Chang, Stephen J. Lockett, David A. Wink
×Abstract
Mammalian skin is a vital barrier with the epidermis serving as its protective outer layer, continually undergoing renewal. Given that loss of the epidermis or its barrier function is lethal for mammals, multiple stem cell populations likely exist for the interfollicular epidermis (IFE), enhancing evolutionary survival. Here, we demonstrate that transcription factor KROX20 marks a heterogeneous stem cell population in the upper and middle mouse hair follicle (HF), partially overlapping with known HF stem cell markers in those regions. Lineage tracing in mice using different reporter lines shows that Krox20-lineage cells migrate from the HF to the IFE, contributing to both basal and suprabasal layers during adulthood. Spatial transcriptomics data corroborate our findings. Depletion of epithelial Krox20-expressing cells leads to epidermal hyperplasia and a disruption of stratification during homeostasis. Our study highlights the contribution of hair follicle Krox20-lineage cells to the IFE and the regulation of epidermal homeostasis.
Authors
Elnaz Ghotbi, Edem Tchegnon, Ze Yu, Tracey Shipman, Zhiguo Chen, Yumeng Zhang, Renee M. McKay, Chao Xing, Chung-Ping Liao, Lu Q. Le
×Abstract
X-linked Lymphoproliferative Syndromes (XLP), arising from mutations in SH2D1A or XIAP genes, are characterized by fulminant Epstein-Barr virus (EBV) infection. Lymphomas occur frequently in XLP-1 and in other congenital conditions with heightened EBV susceptibility, but not in XLP-2. Why XLP-2 patients are apparently protected from EBV-driven lymphomagenesis remains a key open question. To gain insights, newly EBV-infected versus receptor-stimulated primary B cells from XLP-2 patients or with XIAP CRISPR editing were compared with healthy controls. XIAP perturbation impeded outgrowth of newly EBV-infected B cells, but not of CD40 ligand and interleukin-21–stimulated B cells. XLP-2–deficient B cells showed significantly lower EBV transformation efficiency than cells from healthy controls. Interestingly, EBV-immortalized lymphoblastoid cell proliferation was not impaired by XIAP knockout, implicating a XIAP role in early EBV B cell transformation. Mechanistically, nascent EBV infection activated p53-mediated apoptosis signaling, which was counteracted by XIAP in control cells. With XIAP deficiency, EBV markedly elevated apoptosis rates over the first 2 weeks of infection. IFN-γ, whose levels are increased with severe XLP2 EBV infection, markedly increased newly EBV-infected B cell apoptosis. These findings underscored XIAP’s crucial role in support of the earliest stages of EBV-mediated B cell immortalization and provide insights into the curious absence of EBV+ lymphoma in patients with XLP-2.
Authors
Yizhe Sun, Janet Chou, Kevin D. Dong, Steven P. Gygi, Benjamin E. Gewurz
×Abstract
Metabolic health is influenced by adipose tissue, and obesity and lipodystrophy are characterized by inflammation and metabolic dysfunction. Whereas obesity and lipodystrophy treatments involve pharmacological approaches and lifestyle changes, these therapies require long-term, repeated dosing and are not successful for all patients. Gene therapy with targets such as FGF21 and soluble TGF-β receptor 2 (sTGFBR2) provides an alternative approach, specifically in lipodystrophy. Preclinical experiments in mice housed at 22°C are confounded by a mild cold stress not generally experienced by humans, which can negatively affect translation of metabolic therapeutics. In this study, we investigated effects of FGF21/sTGFBR2 combination gene therapy on obese and lipodystrophic mice and how housing temperature influences therapeutic efficacy. In obese mice, FGF21/sTGFBR2 improved insulin resistance and hyperlipidemia more dramatically at warmer temperatures. In lipodystrophic mice on a high-fat diet, combination therapy required adipose tissue to improve insulin resistance at 30°C, whereas FGF21 alone improved insulin resistance at 22°C. Transcriptomic analyses revealed that lipodystrophic mice had upregulated hepatic cell proliferation and fibrosis pathways and that FGF21 promoted hepatic metabolism. Thus, metabolic dysfunction caused by lipodystrophy is improved by targeting FGF21 and TGFB signaling, but effectiveness in preclinical models may be dependent upon environmental temperature and presence of adipose tissue.
Authors
Jessica N. Maung, Yang Chen, Keegan S. Hoose, Rose E. Adler, Hadla Hariri, Mia J. Dickson, Taryn A. Hetrick, Gabriel A. Ferguson, Rebecca L. Schill, Hiroyuki Mori, Romina M. Uranga, Kenneth T. Lewis, Isabel D.K. Hermsmeyer, Donatella Gilio, Christopher de Solis, Amber Toliver, Noah Davidsohn, Elif A. Oral, Ormond A. MacDougald
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Abstract
Authors
Jayanta Mondal, Patrick Nylund, Prit Benny Malgulwar, William E. Johnson, Jason T. Huse
Abstract
We conceived of a type of antitumor mechanism of action by which a soluble target in the tumor microenvironment, such as a tumor-driving growth factor, can be phagocytized along with cancer cells via antibody-dependent cellular phagocytosis (ADCP) using an antibody bispecific for the soluble target and a solid target overexpressed on the cancer cell surface. We explored this concept through engineering bispecific antibodies (BsAbs) co-targeting human epidermal growth factor receptor-2 (HER2) and vascular endothelial growth factor A (VEGFA) in an scFv-IgG format (VHS). We showed that the HER2-VEGFA BsAbs but not the parental antibodies alone or in combination induced co-phagocytosis of VEGFA and HER2-overexpressing cancer cells by tumor-associated macrophages via ADCP. In both immunocompromised and immunocompetent mice with aggressive tumors, the BsAbs demonstrated greater anti-metastasis activity and produced a greater survival benefit than the parental antibodies alone or in combination, in a manner dependent on Fcγ receptors on the macrophages. Our results provide proof of the concept that HER2-VEGFA BsAbs achieve enhanced antitumor activity by leveraging HER2 overexpressed on the cancer cell surface to induce co-phagocytosis of VEGFA. Our findings warrant clinical testing of the strategy to treat metastasis and recurrence of HER2-overexpressing solid tumors that respond to anti-VEGFA therapy.
Authors
Yang Lu, Songbo Qiu, Zhen Fan
Abstract
BACKGROUND. Understanding age-associated differences in acute and memory adaptive immunity to SARS-CoV-2 and how this contributes to more favorable outcomes in children is critically important. METHODS. We evaluated SARS-CoV-2–specific T cell, B cell, and antibody responses in 329 peripheral blood samples collected from non-hospitalized children, adolescents, and adults at three timepoints, including acute and memory timepoints. RESULTS. Most children produced robust CD4+ T cell responses during infection and developed memory CD4+ T cells; however, young children <4 years old often had undetectable CD4+ T cell responses compared to older children and adults. Young children also generated reduced frequencies of memory B cells; despite this, they mounted substantial and durable neutralizing antibody responses. CD4+ T cell responses in children were biased towards non-spike epitopes, especially in asymptomatic cases. Memory B cells in children were preferentially classical memory or, paradoxically, CXCR3+. CONCLUSION. These findings support the concept that the kinetics and composition of T and B cell responses shift across age groups and may be associated with milder COVID-19 outcomes in children.
Authors
L. Benjamin Hills, Numana Bhat, Jillian H. Hurst, Amber Myers, Thomas W. Burke, Micah T. McClain, Elizabeth Petzold, Alexandre T. Rotta, Nicholas A. Turner, Alba Grifoni, Daniela Weiskopf, Yvonne Dogariu, Genevieve G. Fouda, Sallie R. Permar, Alessandro Sette, Christopher W. Woods, Matthew S. Kelly, Shane Crotty
Abstract
Maternal low thyroxine (T4) serum levels during the first trimester of pregnancy correlate with cerebral cortex volume and mental development of the progeny, but why neural cells during early fetal brain development are vulnerable to maternal T4 levels remains unknown. In this study, using iPSCs obtained from a boy with a loss-of-function mutation in MCT8—a transporter previously identified as critical for thyroid hormone uptake and action in neural cells—we demonstrate that thyroid hormones induce transcriptional changes that promote the progression of human neural precursor cells along the dorsal projection trajectory. Consistent with these findings, single-cell, spatial, and bulk transcriptomics from MCT8-deficient cerebral organoids and cultures of human neural precursor cells underscore the necessity for optimal thyroid hormone levels for these cells to differentiate into neurons. The controlled intracellular activation of T4 signaling occurs through the transient expression of the enzyme type 2 deiodinase, which converts T4 into its active form, T3, alongside the coordinated expression of thyroid hormone nuclear receptors. The intracellular activation of T4 in NPCs results in transcriptional changes important for their division mode and cell cycle progression. Thus, T4 is essential for fetal neurogenesis, highlighting the importance of adequate treatment for mothers with hypothyroidism.
Authors
Federico Salas-Lucia, Sergio Escamilla, Amanda Charest, Hanzi Jiang, Randy Stout, Antonio C. Bianco
Abstract
In vitro studies have implicated orphan receptor GPRC5B in β-cell survival, proliferation and insulin secretion, but its relevance for glucose homeostasis in vivo is largely unknown. Using tamoxifen-inducible, β-cell-specific GPRC5B knockout mice (Ins-G5b-KOs) we show here that loss of GPRC5B does not affect β-cell function in the lean state, but results in strongly reduced insulin secretion and disturbed glucose tolerance in mice subjected to high fat diet for 16 weeks. Flow cytometry and single-cell expression analyses in islets from obese mice show a reduced β-cell abundance and a less mature β-cell phenotype in Ins-G5b-KOs. Expression of β-cell-specific transcription factor MafA is reduced both on the RNA and protein level, as are transcripts of MafA target genes. Mechanistically, we show that phosphorylation of cAMP response element-binding protein (CREB), a major regulator of MafA expression, is reduced in islets of obese Ins-G5b-KOs, and that this phenotype precedes the downregulation of MafA and MafA target genes. Taken together, GPRC5B helps to maintain mature β-cell function in obesity through cAMP/CREB-dependent regulation of MafA expression.
Authors
Tianpeng Wang, Remy Bonnavion, Janett Piesker, Stefan Günther, Nina Wettschureck
