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Abstract
Obesity is a chronic progressive disease strongly linked to numerous comorbidities. This is underpinned by a chronic inflammatory environment and significant immune dysregulation. γδ T cells are unconventional T cells that display innate and adaptive characteristics, the predominant one being their independence of MHC restriction. In humans, γδ T cells represent up to 5% of the peripheral blood T cell compartment and are capable of rapidly producing a range of effector cytokines and driving cytotoxic responses. This is critical for protection from both bacterial and viral infections. We investigated circulating γδ T cell metabolic and functional responses in cohorts of people living with obesity (PWO) and people without obesity. We showed that PWO have reduced Vδ2+ T cell frequencies, and their effector responses are diminished following stimulation. We identified that the CD98-LAMTOR5-mTORC1 metabolic axis was critical for functional responses, and demonstrated significant defects in each component of this axis in PWO. Furthermore, STAT5 the initiator of amino acid metabolism was also decreased in PWO. Finally, we showed restoration of this metabolic axis after bariatric surgery, combined with robust improvements in functional responses. Collectively, our data highlighted that obesity drives a reversible dysregulation of Vδ2+ T cells by disrupting cellular metabolism.
Authors
Ciara L. Flynn, Eimear K. Ryan, Cian Davis, Czara A. Kennedy, Katherine G. Egan, Aimee Brennan, Philip Mc Entee, Kirstan Murphy, Niamh Lynam-Lennon, Linda V. Sinclair, Nicholas Jones, Donal O'Shea, Helen M. Heneghan, Andrew E. Hogan
Abstract
Exposure of humans to food insecurity (FI), involving sporadic access and low nutritional quality, is associated with later life development of metabolic disease phenotypes, but mechanisms are poorly understood. We exposed very young rats to a 20-day FI intervention or ad-lib (AL) feeding, using either standard chow (SC) or high fat/high sucrose (HF/HS) diets, followed by continued AL feeding on the respective diets for 10-13 weeks. We found that male, but not female rats subjected to FI on the HF/HS diet had increased body fat percentage, ratio of adipose to body weight, and fat cell size compared to AL rats, coupled with metabolomic and transcriptomic profiles consistent with reduced fatty acid oxidation in the liver and maladaptive remodeling of adipose tissue. These changes were specific to HF/HS feeding and did not occur with SC diet. Our study defines sex- and diet-specific metabolic remodeling responses to FI that may contribute to future disease phenotypes.
Authors
Jie An, Jessica Cannavino, Ashley Williams, Akshay Bareja, Wenxin Tong, Olga Ilkayeva, Michael Muehlbauer, Danhong Lu, Robert A. Hollander, Sarah Armstrong, Rana K. Gupta, Christopher B. Newgard
Abstract
Bone morphogenetic protein-2 (BMP2) is used clinically to promote bone regeneration, but dose-limiting side effects restrict its clinical utility. Canonical Wnt signaling is essential for bone formation, and R-spondin-2 (RSPO2) is a secreted Wnt agonist highly expressed by osteoprogenitors. We found that BMP2 strongly induced RSPO2 during early human mesenchymal stem cell (hMSC) osteoblast differentiation. Recombinant RSPO2 synergized with BMP2 in both hMSCs and MC3T3-E1 preosteoblasts, whereas RSPO2 silencing impaired BMP2-driven osteogenic responses. In a murine critical-size calvarial defect model, co-delivery of RSPO2 and a suboptimal dose of BMP2 yielded significantly more new bone than BMP2 alone, while RSPO2 alone was ineffective. Enhanced canonical Wnt activation with BMP2-RSPO2 co-treatment was shown with an in vivo Wnt reporter mouse. Bulk RNA sequencing of MC3T3-E1 cells revealed that BMP2-RSPO2 co-treatment differentially activated osteogenesis-related genes and pathways compared to BMP2 alone. The guanine exchange factor (GEF), Prex1, was selectively upregulated by BMP2-RSPO2 co-treatment, and was required for RSPO2-mediated enhancement of BMP2-induced osteoblastogenesis. These findings identify RSPO2 as an enhancer of BMP2-driven osteogenesis, amplifying Wnt activation and involving PREX1-dependent signaling. RSPO2 or PREX1 activation may represent a co-therapy that could enhance BMP2 efficacy while mitigating the adverse effects of high-dose BMP2.
Authors
Buchan Jiang, Erin B. Meymarian, Shije Shahin, Jack T. Wilkening, Alexander J. Knights, Archana Sanjay, Tristan Maerz, Yadav Wagley, Kurt D. Hankenson
Abstract
The inflammasome is an innate immune complex responsible for aberrant interleukin-1β (IL-1β) signaling in numerous chronic inflammatory diseases, including gout and Alzheimer’s disease. The inflammasome is composed of several proteins, including the apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC). We developed vaccines targeting various regions of ASC using a Qβ virus-like particle (VLP) platform to assess the efficacy of anti-ASC antibodies for inhibiting inflammasome activity. Using a mouse model of gout, we assessed seven vaccines targeting mouse ASC for their ability to reduce inflammasome activation and neutrophil responses. Three vaccines targeting different regions of the ASC protein (pyrin domain, linker region, and the caspase activation and recruitment domain) successfully targeted ASC, reduced IL-1β, and reduced neutrophil activation. Combining these three vaccines into one cocktail vaccine yielded similar efficacy in the gout model with a favorable safety profile. The combined ASC vaccine also reduced inflammasome levels and pathologically phosphorylated tau in a transgenic mouse model of tauopathy and did not significantly impair host immune responses to bacterial or viral infections. Thus, Qβ-VLP vaccines against ASC can neutralize pathological inflammasome activity across multiple inflammatory disease models.
Authors
Jonathan Hulse, Zachary Villaseñor, Samuel Kress, Kathryn Sánchez, Julianne Peabody, Kimberly A. Morrissey, Alan McNolty, Benjamin Lantz, Laura Gonzalez Bosc, Judy L. Cannon, Seth Daly, Bryce Chackerian, Kiran Bhaskar
Abstract
Hemophagocytic Lymphohistiocytosis (HLH) is a hyperinflammatory syndrome with multiple contributors, often including an infectious trigger. The Macrophage Activation Syndrome (MAS) subtype is linked to marked IL-18 excess, cytotoxic T-lymphocyte (CTL) activation, and natural killer (NK) cell abnormalities. We asked how excess IL-18 shapes NK and CTL responses to viral challenge. Mice with chronic IL-18 overproduction (Il18tg), showed baseline NK-cytopenia and CTL activation resembling MAS-susceptible patients. NK transcriptomes reflected IL-18/IFNg-axis activation and cell cycle upregulation. LCMV infection of Il18tg mice causes HLH/MAS without affecting viral control, but is not a significant NK challenge. Early after infection with NK-dependent mousepox, Il18tg NKs failed to activate appropriately, but CTLs quickly hyperactivated and mousepox control remained intact. Mousepox-infected Il18tg mice then developed signs of HLH/MAS including hepatosplenic necrosis. Their viral control was impaired, possibly because they failed to expand mousepox-specific CTLs. Il18bpKO mice, despite more normal resting lymphocytes, succumbed similarly to viremic HLH/MAS. Transfer of pre-activated NKs into Il18tg mice partially rescued virus-specific CTL responses, viral control, and survival. Thus, excess IL-18 contributes to HLH/MAS via disparate effects on CTL and NK cells, demonstrating a novel, context-specific NK immunodeficiency and highlighting how subtle host-pathogen interactions can affect the mechanisms and treatment rationale of life-threatening HLH/MAS.
Authors
Jemy A. Varghese, Leonardo Huang, Stephen D. Carro, Emily E. Landy, Anastasia Frank-Kamenetskii, Hannah Klinghoffer, Jeremy A. Morrissette, Vinh Dang, Laurence C. Eisenlohr, Scott W. Canna
Abstract
Glioblastoma (GBM) is a lethal brain tumor with a 95% five-year mortality rate, and remains a major unmet clinical need. An innovative approach to target GBM is administration of chimeric antigen receptor (CAR) T cells. In this study we identified B7-H3 as a favorable target antigen for CAR T cell therapy of GBM and developed a B7-H3 targeting CAR T cell. This CAR demonstrates robust, antigen-specific cytolysis and cytokine production, low tonic signaling, and preservation of a stem/naïve cell phenotype. Using orthotopic xenograft models of GBM we show that a single intravenous administration of this B7-H3 targeted CAR confers tumor control, and long-term survival. We identified upregulation of T cell inhibitory ligands PD-L1 and PD-L2 as a mechanism of resistance, and modified our B7-H3 targeting CAR vector to include a secreted a PD-1 blocking scFv. We further demonstrate that concomitant PD-1 blockade by the secreted PD-1 blocking scFv augments the antitumor capabilities of B7-H3-targeting CAR T cells through increased intratumoral infiltration by the CAR T cells and improved effector function. These data demonstrate B7-H3 targeting CAR T cells with concomitant PD-1 blockade is a safe and efficient method for improving the antitumor capacity of CAR T cells for GBM.
Authors
Jonathan F. Khan, Parwiz Abrahimi, Winson Cai, Lauren Dong, Kenny Kwok-Hei Yu, Svena Verma, Yacine Marouf, Sadna Budhu, Tara Pal Chaudhuri, Valeria Estrada Navarro, Mamadou A. Bah, Kelsey Hopland, Yanhong Yang, Terence J. Purdon, Ileana C. Miranda, Viviane Tabar, Jedd D. Wolchok, Taha Merghoub, Renier J. Brentjens
Abstract
Authors
Rocio J. Jimenez-Valdes, Quoc Vo, Alison Morris, Chad Steele, Seyed Mehdi Nouraie, Jonathan K. Alder, Kambez H. Benam
Abstract
Although 95% of serotonin in the human body is produced in the gastrointestinal tract, most prior research work has focused on the brain. Despite its abundance in the gut, serotonin’s role in early intestinal development remains poorly understood. Here we show that serotonin is detected in both the small intestine and large intestine as early as 14 to 15 weeks gestational age. Using single-cell transcriptomics with histological validation, we generated a spatiotemporal atlas of serotonin and serotonin-related genes in the human gut from first trimester to late adulthood. The serotonin synthesis gene, TPH1, was exclusively expressed in enteroendocrine cells at all time points analyzed, with the highest expression in the second trimester. The serotonin reuptake gene, SLC6A4, was largely restricted to mature absorptive enterocytes and increased postnatally. Serotonin receptors also displayed distinct cellular and developmental expression patterns. HTR1E was confined to the first trimester during highly proliferative stage. HTR4 was enriched for in crypt regions, suggesting a role in proliferation for serotonin. Finally, HTR3E was associated with tuft cells throughout development. Together, these findings reveal the dynamic, cell-type-specific regulation of serotonin in the developing human gut, suggesting its importance in early intestinal development, and provide a framework to study its roles in intestinal development and diseases.
Authors
Long Phan, Lauren Smith, Kristin M. Milano, Weihong Gu, Madison S. Strine, Harvey J. Kliman, Liza Konnikova
Abstract
Testosterone is a key determinant of red blood cell (RBC) biology and susceptibility to hemolysis; however, its contribution to donor-dependent variation in RBC quality and transfusion effectiveness remains unclear. Using data from 2,357 male participants in the NHLBI REDS-III RBC-Omics study, we quantified plasma total testosterone, free testosterone (bioavailable form), and androstenedione and evaluated their associations with donor characteristics, RBC hemolysis, and recipient post-transfusion hemoglobin increments, a clinical measure of RBC transfusion effectiveness. Subphysiological testosterone concentrations were common (~35%) and independently associated with increased storage and osmotic hemolysis. Frequent blood donations were independently associated with lower circulating free testosterone concentrations, even after adjustment for demographic and hematologic factors. Genome-wide association analyses identified loci associated with circulating testosterone, including regions near SHBG, TNFSF12, and the long noncoding RNA BALR6. Several testosterone variants were associated with RBC transfusion effectiveness. Specifically, variants associated with lower testosterone (e.g., TNFSF12) corresponded to higher post-transfusion hemoglobin increments (+9%), whereas BALR6 variants associated with higher testosterone were linked to reduced hemoglobin increments (–40%). In contrast, androstenedione-associated variants were not related to hemolysis or transfusion outcomes. Together, these findings demonstrate that genetic and physiologic variation in testosterone contributes to inter-individual variability in RBC quality and transfusion effectiveness.
Authors
Fang Fang, Nareg Roubinian, Xutao Deng, Cassie Kemmler, Jost Klawitter, Jelena Klawitter, Touraj Shokati, Uwe Christians, Grier P. Page, Tamir Kanias
Abstract
The role of CD8+ T cells in filarial infections remains poorly understood. Given the chronic nature of these infections, individuals living in endemic regions are frequently exposed to other pathogens including viruses. Because CD8 cells are essential for antiviral immunity, understanding how filarial infections shape the cytotoxic compartment is essential to elucidate their impact on bystander immunity. We evaluated the phenotype and function of CD8+ T cells from Loa loa-infected (Fil+) and -uninfected (Fil–) individuals at baseline and following cytomegalovirus (CMV) re-stimulation. Filarial infection was associated with increased activation and proliferation of CD8+ T cells, characterized by elevated expression of Ki-67, CD107a, and production of type 1 and 17 cytokines. Upon CMV re-stimulation, Fil+ individuals showed markedly reduced expansion of antigen-experienced (CD137+) and polyfunctional (CD137+IFN-γ+TNF-α+, CD137+IFN-γ+TNF-α+IL-2+) CD8+ T cells, along with decreased cytotoxic activity. Unbiased clustering analysis revealed markedly reduced frequency of the CD8+CD45RA+CD57+ subset in Fil+ individuals- a population further defined through transcriptomic profiling that showed enrichment for cytolytic gene signatures (GZMB, GNLY, GZMH, CD244, CX3CR1). These results demonstrated that filarial infection is associated with an altered CD8+ T cell profile that is associated with failure to mount effective viral-specific effector responses, including impaired cytokine production and cytotoxic activity.
Authors
Camila Queiroz-Glauss, Justin Lack, Daniel E. Sturdevant, Thomas B. Nutman
Abstract
The hypothesized cellular and molecular mechanisms underlying dystonia are broad and include mutations that perturb Ca2+ signaling, including those affecting voltage gated calcium channels (VGCC). In mice, pharmacological activation of neuronal L-type VGCCs induces dystonia in a dose dependent manner. Here we demonstrate that mice expressing a gain-of-function mutation in the L-type VGCC CaV1.2, associated with Timothy syndrome (TS), exhibit motor dysfunction consistent with dystonia. Although CaV1.2 is broadly expressed throughout peripheral tissues and across the brain, we establish that the dystonia-like behavior is driven by neuronal expression of the mutant calcium channel and observe an associated potential excitatory/inhibitory (E/I) imbalance. Because patients with TS have profound metabolic dysregulation, which is associated with some dystonias, we measured changes in circulating metabolites. The dystonia-like events are sensitive to perturbations in pyruvate metabolism, reminiscent of a subset of dystonias associated with pyruvate dysregulation. Our study provides insight into the potential convergence of previously established causes of dystonia, calcium signaling and metabolic homeostasis.
Authors
Patrick Towers, Hong-Gang Wang, Maiko Matsui, Geoffrey S. Pitt
Abstract
Pneumocystis jirovecii pneumonia (PCP) remains a major cause of life-threatening respiratory failure in people with advanced HIV, yet the biological factors associated with mortality are incompletely understood. We performed integrated transcriptomic, proteomic, and metabolomic profiling of bronchoalveolar lavage fluid from 42 adults with HIV-associated PCP, relating molecular signatures to mortality. We found that fungal burden, measured by sputum immunofluorescence, Pneumocystis qPCR, and 1,3-β-D-glucan, did not differ between survivors and non-survivors or correlate with baseline gas exchange. Instead, non-survivors exhibited a bronchoalveolar immunometabolic failure signature characterised by marked depletion of immunoglobulins and complement, reduced pattern recognition receptors and fibroblast growth factor family proteins, and broad disruption of extracellular matrix organisation. Metabolomic profiling revealed enrichment of arginine-urea cycle and tricarboxylic acid pathways, with coordinated accumulation of arginine, citrulline, and TCA cycle intermediates consistent with nitrosative and mitochondrial stress. An integrated proteo-metabolomic score summarising this state was significantly higher in non-survivors and did not correlate with fungal burden or cytomegalovirus co-infection. In an immunodeficient precision-cut lung slice model, antigen-screened intravenous immunoglobulin restored macrophage-mediated Pneumocystis clearance, providing proof-of-concept for opsonic augmentation. Our findings indicate that mortality in HIV-PCP is defined by profound immunometabolic failure, highlighting humoral depletion and impaired alveolar repair as potential targets for host-directed adjunctive therapy.
Authors
Peter Rossi-Smith, Ayanda Trevor Mnguni, Dora Pungan, Robert J. Samuels, Vaishnavi R. Kumaran, Leena Syed, Trevor Ferris, Kamil Skirlo, Joseph N. Jarvis, Nelesh P. Govender, Graeme Meintjes, Sean Wasserman, Jay K. Kolls, Rachel P.J. Lai
Abstract
BACKGROUND. Body weight and insulin resistance in women increase in midlife. It is not known whether this is driven by the menopause transition or solely by chronological aging. We aimed to determine the role of the menopause transition and menopause-related BMI changes in the development of insulin resistance in midlife women. METHODS. Mixed effects, linear spline modeling of longitudinal data in 1315 women, 42- to 52-years-old, pre- or early perimenopausal in 1995 to 1996 with up to 16 follow up visits by 2018. Homeostatic-model-assessed-insulin-resistance (HOMA-IR) was measured up to 12 times. Date of final menstrual period (FMP) was prospectively determined. RESULTS. HOMA-IR increased faster over a 4-year interval extending from 1.5 years prior to 2.5 years after the FMP, than in the years before or after it; p value for both slope changes < 0.0001. In the referent woman (White, age 52 years at FMP, non-smoker, body mass index [BMI] 25.6 kg/m2 at baseline, and not on sex hormone therapy or statins), the average annualized rate of HOMA-IR increase, adjusted for covariates including changes in BMI, was 1.2%, 4.3%, and 0.9% respectively, before, during, and after the 4-year transition. CONCLUSION. Consistent with an independent effect of the menopause transition, insulin resistance increased significantly faster during the transition (from 1.5 years before the to 2.5 years after the FMP) than in the years preceding or following the transition. Future studies need to investigate mechanisms underpinning this observed association and determine the impact of lifestyle on dampening menopause-associated increases in insulin resistance. FUNDING. National Institutes of Health.
Authors
Arun S. Karlamangla, Wei Juan Han, Preethi Srikanthan, Albert Shieh, Duncan Thomas, Barbara Sternfeld, Monique M. Hedderson, Gail A. Greendale
Abstract
Chronic liver disease affects over a billion people worldwide. Despite diverse etiologies, a unifying feature of chronic liver disease is the liver’s impaired ability to regenerate during progression to cirrhosis, but no common molecular mechanism has been identified. Hepatocyte proliferation and liver regeneration depend on nucleoplasmic calcium (Ca2+) signals, and Ca2+ signals in hepatocytes depend on the type 2 inositol trisphosphate receptor (ITPR2) calcium release channel. Here, we found that ITPR2 was localized in part to the hepatocyte nucleus, and this localization depended on the presence of nucleoporin 62 (NUP62). Loss of either ITPR2 or NUP62 disrupted nuclear Ca2+ signaling, and impaired Ca2+ signals in the nucleus blunted nuclear entry of β-catenin. Remarkably, both ITPR2 and NUP62 are progressively lost from hepatocytes in patients with the four most common types of chronic liver disease. These findings identify a microdomain regulating Ca2+ signaling in the hepatocyte nucleus that becomes progressively disrupted as liver disease progresses. Preservation of this nuclear microdomain may be a novel approach to maintain liver regeneration and slow the progression to cirrhosis in chronic liver disease.
Authors
Jittima Weerachayaphorn, Mateus T. Guerra, Naotaka Kugiyama, Emma Kruglov, Dejian Zhao, Piyachat Chansela, Vitoon Saengsirisuwan, Marie E. Robert, Teruo Utsumi, Yasuko Iwakiri, Michael H. Nathanson
Abstract
Persistent production of type I interferons (IFN-Is) is a hallmark of cutaneous lupus erythematosus (CLE). Ultraviolet (UV) light stimulates IFN-I response in the skin and exacerbates CLE. Here, we identify V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA) as a negative regulator of both basal and UV-induced IFN-I response in the skin and show that VISTA limits skin photosensitivity in an IFN-I-dependent manner, in part through Stimulator of Interferon Genes (STING). Furthermore, we demonstrate a novel role for VISTA in keratinocytes both at steady state and in response to UV light. Conditional deletion of VISTA in epidermal keratinocytes results in a ~10-fold increase in basal skin IFN-I scores and a heightened UV-induced skin injury score, both of which are dependent on IFN-I signaling. VISTA-targeting monoclonal antibodies suppress the UV-induced IFN-I response in human keratinocytes and in mice expressing human VISTA in vivo, thereby reducing UV-induced skin injury scores. Together, these findings identify VISTA as a keratinocyte-intrinsic checkpoint that restrains STING-associated IFN-I response in the skin and suggest VISTA agonism as a therapeutic strategy to limit photosensitivity in CLE.
Authors
Zachary T. Peters, Lindsay K. Mendyka, J'Voughnn A. Blake, Himanshu B. Goswami, Angelique N. Cortez, Grace E. Crossland, Sicong Shan, Elizabeth C. Nowak, Myana Keusch, Mrinal K. Sarkar, Johann E. Gudjonsson, Christopher M. Burns, Dorothea T. Barton, Bruce R. Blazar, Tyler J. Curiel, Rodwell Mabaera, Victoria P. Werth, Andrea Kalus, Keith B. Elkon, Randolph J. Noelle, Sladjana Skopelja-Gardner
Abstract
Missense mutations in the UMOD gene are a well-established genetic cause of autosomal dominant tubulointerstitial kidney disease (ADTKD). Here, we report two ADTKD pedigrees carrying de novo UMOD mutations, p.His36Tyr (H36Y) and p.Trp31Cys (W31C). To elucidate the underlying pathogenic mechanisms and explore targeted therapeutic strategies, we generated a UMODH36Y/+ knock-in mouse model using CRISPR/Cas9 technology, which recapitulated the major clinical manifestations observed in patients. Through single-cell RNA sequencing and experimental validation, we demonstrated that uromodulin mutations triggered endoplasmic reticulum (ER) stress and the unfolded protein response, with ferroptosis identified as the predominant mode of cell death in this disease. These findings were further confirmed in plasmid-transfected cell models expressing UMODH36Y and UMODW31C. Moreover, the molecular chaperone HSPA1A was identified as a potential therapeutic target. Geranylgeranylacetone, targeting HSPA1A as a chaperone drug, effectively mitigated endoplasmic reticulum stress, alleviated ferroptosis, and delayed the progression of renal dysfunction. Based on novel uromodulin mutations, our study reveals a pathogenic ER-ferroptosis axis in ADTKD-UMOD, deepens the insight into the pathogenesis of ADTKD-UMOD, and provides a promising strategy for developing chaperone therapy with drug repurposing in genetic kidney diseases.
Authors
Wen Shi, Yan Yang, Xianli Wen, Qianqian Wu, Jinxuan Wei, Xin-Lu Wang, Junyuan Shen, Siqi Peng, Xiaoliang Zhang, Bi-Cheng Liu, Bin Wang
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis integrates central neural processing and responses to stress with endocrine and metabolic responses. We utilized a monoclonal antibody binding corticotrophin-releasing factor (anti-CRF) to achieve durable HPA axis modulation. In mice, anti-CRF treatment decreased plasma corticosterone, food-intake, body weight and fat mass, but preserved lean mass and improved metabolic parameters including insulin sensitization. These body composition effects were observed in middle aged mice on normal chow or high fat diet, aged mice, and Mc4r-/- and ob/ob mice. Single-dose studies demonstrated impacts on weight gain and body composition lasting beyond the period of pharmacological target engagement. Multi-organ transcriptomic and proteomic analyses revealed organ-specific effects of anti-CRF and are consistent with altered glucocorticoid receptor (GR) signaling as a mediator of the observed phenotypes. These studies support anti-CRF-mediated HPA-axis modulation as a metabolic and anti-obesity therapeutic approach distinct from incretins.
Authors
Zachary A. Krumm, Tariful Islam, Caroline M. Watson, Yong Ran, Yona Levites, Hunter S. Futch, Luming Yin, Edgardo Rodriguez-Lebron, Xuefei Liu, Kazi Farhana Afroz, Ariella Goloborodsky, Thomas B. Ladd, Kristy D. Dillon, Danny Ryu, Jennifer L. Bizon, Jada Lewis, Karen A. Scott, Annette de Kloet, Nicholas T. Seyfried, Eric G. Krause, Karen N. McFarland, Todd E. Golde
Anti-Notch plus endocrine therapy in ER+ breast cancer inhibits cancer stem cells by increasing DAXX
Abstract
Resistance to endocrine therapy (ET) in ER+ breast cancer is mediated by Notch signaling, but the clinical application of anti-Notch therapy has been limited by the lack of predictive biomarkers. To identify Notch-regulated biomarkers, we conducted a pre-surgical window study evaluating ET combined with the γ-secretase inhibitor (GSI) MK-0752. RNA expressions in tumors were measured using an Affymetrix array and by real-time PCR. ET plus GSI showed more genes were decreased than ET alone. Specifically, DAXX, NOXA, and LFNG RNAs were increased, while fifteen additional transcripts were decreased. Mechanistically, GSI reduced Notch1 occupancy at CSL-binding elements within HES1, HEY2, HEYL, CCND1, MKI67, and DAXX genes, and inhibited cancer stem cells (CSCs) by 90% to 100%. This anti-CSC effect required DAXX, while GSI treatment or Notch1/4 knockdown increased DAXX expression, suggesting transcriptional repression by Notch. Using mouse tumor xenograft studies, ET plus MK-0752 resulted in complete regression of MCF-7 tumors, with DAXX-high tumors showing greater treatment sensitivity. Clinically, high DAXX expression was associated with improved recurrence-free and overall survival. This study found that anti-Notch plus ET in ER+ breast cancer inhibits cancer stem cells by increasing DAXX, a promising predictive biomarker. These findings support clinical evaluation of therapies that increase DAXX expression.
Authors
Kathy S. Albain, Debra Wyatt, Andrei Zlobin, Susan G. Hilsenbeck, Cheryl M. Czerlanis, Daniel S. Peiffer, Kyle R. Convington, Constantine Godellas, Shelly S. Lo, Patricia A. Robinson, Kathy Czaplicki, Barbara Busby, Davide Bova, Ping Tang, Patrick J. Stiff, Suzanne A.W. Fuqua, Lucio Miele, Clodia Osipo
Serine palmitoyltransferase (SPT) inhibition in SPTSSA-related complex hereditary spastic paraplegia
Abstract
Defective feedback inhibition of serine palmitoyltransferase (SPT) caused by pathogenic SPTSSA variants underlies childhood-onset complex hereditary spastic paraplegia, yet the developmental timing and therapeutic reversibility of sphingolipid dysregulation remain unclear. We generated a knock-in mouse carrying the disease-associated SptssaT51I variant and show that heterozygous animals exhibit preserved intrinsic SPT activity but impaired ORMDL-mediated regulation, leading to sustained elevation of bioactive sphingolipid intermediates that peak during postnatal myelination. Although gross myelin formation was initially maintained, excess sphingolipid flux rendered oligodendrocytes and neurons selectively vulnerable. Dietary L-serine, which augments SPT substrate availability, amplified sphingolipid accumulation in mutant but not wild-type mice, unmasking progressive spasticity, axonal injury, myelin ultrastructural defects, and, when administered during early postnatal development, severe pulmonary pathology likely responsible for lethality. Pharmacologic SPT inhibition with myriocin normalized sphingolipid synthesis, prevented serine-induced lethality, and reversed neurological and metabolic abnormalities. Translating these findings, treatment of a child with SPTSSA-T51I–associated complex hereditary spastic paraplegia using the FDA approved SPT inhibitor D-Cycloserine resulted in sustained improvement in spasticity, reduced baclofen requirement, and decreased plasma levels of neurofilament light chain (NFL). These data define dysregulated sphingolipid biosynthesis as a developmentally and metabolically sensitive driver of neurodegeneration and suggest SPT inhibition as a mechanistically grounded therapeutic strategy.
Authors
Yi Gong, Robert Thompson, Ashley M. Glover, Kenneth Gable, Sita D. Gupta, Natalie Golovanov, Julie Tassinari, Nathan Casey, Brian D. Wishart, Elise L. Townsend, April Qian, Martin Selig, Armen Yerevanian, Teresa M. Dunn, Florian Eichler
Abstract
Premature infants often require supplemental oxygen therapy, a major risk factor for bronchopulmonary dysplasia and subsequent neurodevelopmental impairment. To determine how neonatal hyperoxia affects prefrontal cortex (PFC) development, we exposed neonatal mice to 85% oxygen (O₂) from postnatal day (P)1–P14 and performed integrated single-nucleus transcriptomic and chromatin accessibility profiling with in vivo and in vitro validation. Hyperoxia induced sex-dependent cellular remodeling, reducing L4/5 intratelencephalic projecting glutamatergic neurons in females and mature oligodendrocytes in males. Across both sexes, hyperoxia suppressed oligodendrocyte maturation, with decreased expression of the myelination genes proteolipid protein 1 (Plp1) and myelin basic protein (Mbp), altered chromatin accessibility, and increased oligodendrocyte transcription factor 2 (OLIG2) protein expression. Regulatory responses were sex specific, with tumor protein p53 (TP53)-regulated metabolic disruption and lysine demethylase 3A (Kdm3a) induction in females, and Netrin-1 signaling in males. Hyperoxia impaired oligodendrocyte progenitor cell (OPC) proliferation and differentiation. These abnormalities were recapitulated in postmortem PFC tissue from infants with BPD and human induced pluripotent stem cell (iPSC)-derived OPCs. These findings show that neonatal hyperoxia disrupts PFC development through sex-dependent effects on neuronal and oligodendrocyte lineages while converging on impaired myelination, highlighting oligodendrocyte dysfunction as a clinically relevant consequence of neonatal oxygen exposure.
Authors
Xingrao Ke, Wei Yu, Carl F. Schreck, Joseph M. Varberg, Melissa A. Gener, Daniel A. Louiselle, Sheng Xia, Sherry M. Mabry, Heather L. Menden, Venkatesh Sampath, Robert H. Lane, Kaela M. Varberg
