Issue published March 3, 2025 Previous issue
On the cover: Carnitine palmitoyl transferase 1a regulates hematopoietic stem cell maintenance
Li et al. report on the role of carnitine palmitoyl transferase 1a (Cpt1a) in maintaining stemness of hematopoietic stem cells and its regulation of mitochondrial metabolism by balancing fatty acid oxidation and glucose-fueled oxidative phosphorylation. The cover art depicts the contrasting effects of fatty acids and high-glucose concentrations on stem cell integrity. Pink droplets represent fatty acid–enriched microenvironments, where stem cells appear robust and stable. In contrast, blue droplets symbolize glucose-rich conditions, associated with loss of stemness and differentiation of stem cells. Image credit: Jue Li and Gang Huang.
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Reviews
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Implications of gene × environment interactions in post-traumatic stress disorder risk and treatment
Abstract
Exposure to traumatic stress is common in the general population. Variation in the brain’s molecular encoding of stress potentially contributes to the heterogeneous clinical outcomes in response to traumatic experiences. For instance, only a minority of those exposed to trauma will develop post-traumatic stress disorder (PTSD). Risk for PTSD is at least partially heritable, with a growing number of genetic factors identified through GWAS. A major limitation of genetic studies is that they capture only the genetic component of risk, whereas PTSD by definition requires an environmental traumatic exposure. Furthermore, the extent, timing, and type of trauma affects susceptibility. Here, we discuss the molecular mechanisms of PTSD risk together with gene × environment interactions, with a focus on how either might inform genetic screening for individuals at high risk for disease, reveal biological mechanisms that might one day yield novel therapeutics, and impact best clinical practices even today. To close, we discuss the interaction of trauma with sex, gender, and race, with a focus on the implications for treatment. Altogether, we suggest that predicting, preventing, and treating PTSD will require integrating both genotypic and environmental information.
Authors
Carina Seah, Anne Elizabeth Sidamon-Eristoff, Laura M. Huckins, Kristen J. Brennand
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Neuroendocrine tumors (NETs) are a diverse group of malignancies that can occur in various organs, with a notable prevalence in the lungs and gastrointestinal tract, which are the focus of this Review. Although NETs are rare in individual organs, their incidence has increased over recent decades, highlighting the urgent need for current classification systems to evolve by incorporating recent advances in the understanding of NET biology. Several omics studies have revealed molecular subtypes, which, when integrated into existing classification frameworks, may provide more clinically relevant insights for patients with NETs. This Review examines recent progress in elucidating the biology of NETs, with a particular emphasis on the tumor microenvironment and cells of origin. The existence of different cells of origin, which may contribute to distinct molecular groups, along with profiles of immune infiltration — despite being generally low — could explain the emergence of more aggressive cases and the potential for metastatic progression. Given the molecular heterogeneity of NETs and the diversity of their microenvironments and different cells of origin, there is an urgent need to develop morphomolecular classification systems. Such systems would make it possible to better characterize tumor progression, identify new therapeutic targets, and, ultimately, guide the development of personalized therapies.
Authors
Lynnette Fernandez-Cuesta, Nicolas Alcala, Emilie Mathian, Jules Derks, Chrissie Thirlwell, Talya Dayton, Ilaria Marinoni, Aurel Perren, Thomas Walter, Matthieu Foll
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Bacteriophage (phage) therapy has emerged as a promising solution to combat the growing crisis of multidrug-resistant (MDR) infections. There are several international centers actively engaged in implementation of phage therapy, and recent case series have reported encouraging success rates in patients receiving personalized, compassionate phage therapy for difficult-to-treat infections. Nonetheless, substantial hurdles remain in the way of more widespread adoption and more consistent success. This Review offers a comprehensive overview of current phage therapy technologies and therapeutic approaches. We first delineate the common steps in phage therapy development, from phage bank establishment to clinical administration, and examine the spectrum of therapeutic approaches, from personalized to fixed phage cocktails. Using the framework of a conventional drug development pipeline, we then identify critical knowledge gaps in areas such as cocktail design, formulation, pharmacology, and clinical trial design. We conclude that, while phage therapy holds promise, a structured drug development pipeline and sustained government support are crucial for widespread adoption of phage therapy for MDR infections.
Authors
Minyoung Kevin Kim, Gina A. Suh, Grace D. Cullen, Saumel Perez Rodriguez, Tejas Dharmaraj, Tony Hong Wei Chang, Zhiwei Li, Qingquan Chen, Sabrina I. Green, Rob Lavigne, Jean-Paul Pirnay, Paul L. Bollyky, Jessica C. Sacher
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Commentaries
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Abstract
N-methyl-d-aspartate (NMDA) receptor–mediated autoimmune encephalitis (NMDAR-AE) is the most common cause of autoimmune encephalitis, especially in children and young adults. The disorder is caused by antibodies directed against the GluN1 protein, an obligatory constituent of NMDA receptors, which are key signaling molecules in brain development, learning and memory, and executive function. The manuscript by Zhou et al. offers key insights into aberrant development of cortical pathways that may underly persistent sensorimotor deficits associated with this encephalitis in a newly generated mouse model. This study convincingly links transient exposure to a patient-derived anti-GluN1 mAb during a critical developmental period to lasting disruptions in interhemispheric connectivity through callosal projections. These findings provide insight into the impact of a prevalent autoimmune disorder on fundamental aspects of brain development and establish a model system that could be further employed to probe other aspects of NMDAR-AE pathogenesis.
Authors
Puneet Opal, Geoffrey T. Swanson
×Abstract
Cellular senescence is a cell state induced by irreparable cellular damage. The hallmark of senescence is cell cycle exit, yet neurons, which are postmitotic from birth, have also been found to undergo senescence. Neuronal senescence is prevalent in aging as well as in neurodegenerative disease. However, a role for senescence in epilepsy is virtually unexplored. In this issue of the JCI, Ge and authors used resected brain tissue from individuals with drug-resistant epilepsy, a genetic knockout mouse model, and a chemoconvulsant mouse model, to demonstrate a subset of cortical pyramidal senescent neurons that likely contribute to the pathophysiology of epilepsy. These findings highlight senescence as a possible target in precision-therapy approaches for epilepsy and warrant further investigation.
Authors
Gemma L Carvill
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Ischemic stroke causes scars in the CNS that impede functional recovery, and there is a need for therapeutics to improve recovery after the acute phase. Scar-resident myofibroblasts and the PDGF pathway have been implicated in stroke pathology. In this issue of the JCI, Protzmann et al. report that inhibition of PDGF-CC or its receptor, PDGFRα, reduces the myofibroblast population and improves functional recovery after ischemic stroke in mice. Importantly, PDGFRα inhibition was effective in improving functional recovery even when initiated 24 hours after stroke, which suggests opportunities for later treatment by targeting the PDGF pathway. This study demonstrates the therapeutic potential of enhancing stroke recovery even after acute damage and blood-brain barrier dysfunction has already occurred.
Authors
Hae Ryong Kwon, Lorin E. Olson
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Research Letters
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Abstract
Authors
Felicitas E. Hengel, Silke Dehde, Oliver Kretz, Jonas Engesser, Tom Zimmermann, Tobias B. Huber, Nicola M. Tomas
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Authors
Steven S. An, Gaoyuan Cao, Kwangmi Ahn, Jordan Lee, Dae Young Jung, Loren Denlinger, John Fahy, Elliot Israel, Wendy Moore, Brenda Phillips, David Mauger, Sally Wenzel, Reynold A. Panettieri Jr.
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Research Articles
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Abstract
Ischemic stroke is a major cause of disability in adults. Early treatment with thrombolytics and/or thrombectomy can significantly improve outcomes; however, following these acute interventions, treatment is limited to rehabilitation therapies. Thus, identification of therapeutic strategies that can help restore brain function in the post-acute phase remains a major challenge. Here we report that genetic or pharmacologic inhibition of the PDGF-CC/PDGFRα pathway, which has previously been implicated in stroke pathology, significantly reduced myofibroblast expansion in the border of the fibrotic scar and improved outcome in a sensory-motor integration test after experimental ischemic stroke. This was supported by gene expression analyses of cerebrovascular fragments showing upregulation of profibrotic/proinflammatory genes, including genes of the TGF pathway, after ischemic stroke or intracerebroventricular injection of active PDGF-CC. Further, longitudinal intravital 2-photon imaging revealed that inhibition of PDGFRα dampened the biphasic pattern of stroke-induced vascular leakage and enhanced vascular perfusion in the ischemic lesion. Importantly, we found PDGFRα inhibition to be effective in enhancing functional recovery when initiated 24 hours after ischemic stroke. Our data implicate the PDGF-CC/PDGFRα pathway as a crucial mediator modulating post-stroke pathology and suggest a post-acute treatment opportunity for patients with ischemic stroke targeting myofibroblast expansion to foster long-term CNS repair.
Authors
Jil Protzmann, Manuel Zeitelhofer, Christina Stefanitsch, Daniel Torrente, Milena Z. Adzemovic, Kirils Matjunins, Stella J.I. Randel, Sebastian A. Lewandowski, Lars Muhl, Ulf Eriksson, Ingrid Nilsson, Enming J. Su, Daniel A. Lawrence, Linda Fredriksson
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Multiple sclerosis (MS) is a debilitating autoimmune disease of the CNS, which is characterized by demyelination and axonal injury and frequently preceded by a demyelinating event called clinically isolated syndrome (CIS). Despite the importance of B cells and autoantibodies in MS pathology, their target specificities remain largely unknown. For an agnostic and comprehensive evaluation of autoantibodies in MS, we developed and employed what we believe to be a novel autoantigen discovery technology, the Antigenome Platform. This Platform is a high-throughput assay comprising large-fragment (approximately 100 amino acids) cDNA libraries, phage display, serum antibody screening technology, and robust bioinformatics analysis pipelines. For autoantibody discovery, we assayed serum samples from CIS patients who received either placebo or treatment who were enrolled in the REFLEX clinical trial, which assessed the effects of IFN-β-1a (Rebif) clinical and MRI activity in patients with CIS. Serum autoantibodies from patients with CIS were significantly and reproducibly enriched for known and previously unreported protein targets; 166 targets were selected by over 10% of patients’ sera. Further, 10 autoantibody biomarkers associated with disease activity and 17 associated with patient response to IFN-β-1a therapy. These findings indicate widespread autoantibody production in MS and provide biomarkers for continued study and prediction of disease progression.
Authors
Europe B. DiCillo, Evgueni Kountikov, Minghua Zhu, Stefan Lanker, Danielle E. Harlow, Elizabeth R. Piette, Weiguo Zhang, Brooke Hayward, Joshua Heuler, Julie Korich, Jeffrey L. Bennett, David Pisetsky, Thomas Tedder
×Abstract
N-methyl-d-aspartate (NMDA) receptor–mediated autoimmune encephalitis (NMDAR-AE) frequently results in persistent sensory-motor deficits, especially in children, yet the underlying mechanisms remain unclear. This study investigated the long-term effects of exposure to a patient-derived GluN1-specific mAb during a critical developmental period (from postnatal day 3 to day 12) in mice. We observed long-lasting sensory-motor deficits characteristic of NMDAR-AE, along with permanent changes in callosal axons within the primary somatosensory cortex (S1) in adulthood, including increased terminal branch complexity. This complexity was associated with paroxysmal recruitment of neurons in S1 in response to callosal stimulation. Particularly during complex motor tasks, mAb3-treated mice exhibited significantly reduced interhemispheric functional connectivity between S1 regions, consistent with pronounced sensory-motor behavioral deficits. These findings suggest that transient exposure to anti-GluN1 mAb during a critical developmental window may lead to irreversible morphological and functional changes in callosal axons, which could significantly impair sensory-motor integration and contribute to long-lasting sensory-motor deficits. Our study establishes a new model of NMDAR-AE and identifies novel cellular and network-level mechanisms underlying persistent sensory-motor deficits in this context. These insights lay the foundation for future research into molecular mechanisms and the development of targeted therapeutic interventions.
Authors
Jing Zhou, Ariele L. Greenfield, Rita P. Loudermilk, Christopher M. Bartley, Chun Chen, Xiumin Chen, Morgane A.H. Leroux, Yujun Lu, Deanna Necula, Thomas T. Ngo, Baouyen T. Tran, Patrick S. Honma, Kelli Lauderdale, Chao Zhao, Xiaoyuan Zhou, Hong Wang, Roger A. Nicoll, Cong Wang, Jeanne T. Paz, Jorge J. Palop, Michael R. Wilson, Samuel J. Pleasure
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Radiotherapy can be limited by pneumonitis, which is impacted by innate immunity, including pathways regulated by TRAIL death receptor DR5. We investigated whether DR5 agonists could rescue mice from toxic effects of radiation and found that 2 different agonists, parenteral PEGylated trimeric TRAIL (TLY012) and oral TRAIL-inducing compound (TIC10/ONC201), could reduce pneumonitis, alveolar wall thickness, and oxygen desaturation. Lung protection extended to late effects of radiation including less fibrosis at 22 weeks in TLY012-rescued survivors versus unrescued surviving irradiated mice. Wild-type orthotopic breast tumor–bearing mice receiving 20 Gy thoracic radiation were protected from pneumonitis with disappearance of tumors. At the molecular level, radioprotection appeared to be due to inhibition of CCL22, a macrophage-derived chemokine previously associated with radiation pneumonitis and pulmonary fibrosis. Treatment with anti-CCL22 reduced lung injury in vivo but less so than TLY012. Pneumonitis severity was worse in female versus male mice, and this was associated with increased expression of X-linked TLR7. Irradiated mice had reduced esophagitis characterized by reduced epithelial disruption and muscularis externa thickness following treatment with the ONC201 analog ONC212. The discovery that short-term treatment with TRAIL pathway agonists effectively rescues animals from pneumonitis, dermatitis, and esophagitis following high doses of thoracic radiation exposure has important translational implications.
Authors
Jillian Strandberg, Anna Louie, Seulki Lee, Marina Hahn, Praveen Srinivasan, Andrew George, Arielle De La Cruz, Leiqing Zhang, Liz Hernandez Borrero, Kelsey E. Huntington, Payton De La Cruz, Attila A. Seyhan, Paul P. Koffer, David E. Wazer, Thomas A. DiPetrillo, Stephanie L. Graff, Christopher G. Azzoli, Sharon I. Rounds, Andres J. Klein-Szanto, Fabio Tavora, Evgeny Yakirevich, Abbas E. Abbas, Lanlan Zhou, Wafik S. El-Deiry
×Abstract
The persistent emergence of COVID-19 variants and recurrent waves of infection worldwide underscores the urgent need for vaccines that effectively reduce viral transmission and prevent infections. Current intramuscular (IM) COVID-19 vaccines inadequately protect the upper respiratory mucosa. In response, we have developed a nonadjuvanted, IFN-armed SARS-CoV-2 fusion protein vaccine with IM priming and intranasal (IN) boost sequential immunization. Our study showed that this sequential vaccination strategy of the IM+IN significantly enhanced both upper respiratory and systemic antiviral immunity in a mouse model, characterized by the rapid increase in systemic and mucosal T and B cell responses, particularly the mucosal IgA antibody response. The IN boost triggered a swift secondary immune response, rapidly inducing antigen-specific IgA+ B cells. Further B cell receptor–seq (BCR-seq) analysis indicated that these IgA+ B cells primarily arose through direct class switching from preexisting IgG+ B cells in draining lymph nodes. Notably, our clinical studies revealed that the IN boost after IM vaccination elicited a robust systemic IgA antibody response in humans, as measured in serum. Thus, we believe that our cytokine-armed protein vaccine presents a promising strategy for inducing rapid and potent mucosal protection against respiratory viral infections.
Authors
Yifan Lin, Xuejiao Liao, Xuezhi Cao, Zhaoyong Zhang, Xiuye Wang, Xiaomeng He, Huiping Liao, Bin Ju, Furong Qi, Hairong Xu, Zhenhua Ren, Yanqun Wang, Zhenxiang Hu, Jiaming Yang, Yang-Xin Fu, Jincun Zhao, Zheng Zhang, Hua Peng
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Acetylsalicylic acid (ASA) can exert proanaphylactic effects, but the extent of this phenomenon and its underlying mechanisms are undefined. Yet, low homeostatic prostaglandin E2 (PGE2) levels have been associated with anaphylaxis. In this study, we investigated whether the proanaphylactic effect of ASA is PGE2 dependent. We assessed the effect of ASA in experimental anaphylaxis models, analyzed a large dataset of patients with anaphylaxis, and performed titrated allergen challenges in ASA-treated allergic individuals. Registry data indicated an increased risk for severe anaphylaxis in patients with ASA comedication. ASA pretreatment aggravated allergen-dependent anaphylaxis in mice, whereas histamine-induced anaphylaxis remained unaffected. Exacerbation was due to reduced PGE2, as its stabilization or the use of prostanoid E receptor (EP) agonists reversed the proanaphylactic effects of ASA. EP2-, EP3-, and EP4 receptor–deficient mice revealed that each receptor individually contributed to ASA susceptibility. In patients with allergy, prior ASA intake increased skin responsiveness to allergen but not to histamine. Conversely, the responses of basophils to ex vivo FcεRI aggregation remained unaltered, indicating that ASA operated by enhancing the stimulability of mast cells in a PGE2-dependent manner. Collectively, our data reveal a central role of the PGE2 network in ASA-aggravated anaphylaxis. EP receptors could be potential targets to prevent or alter the outcome of anaphylaxis.
Authors
Philipp Globig, Payam Morakabati, Veronika Höfer, Diana M. Willmes, Magda Babina, Margitta Worm
×Abstract
Eccentric contraction–induced (ECC-induced) force loss is a hallmark of murine dystrophin-deficient (mdx) skeletal muscle that is used to assess efficacy of potential therapies for Duchenne muscular dystrophy. While virtually all key proteins involved in muscle contraction have been implicated in ECC force loss, a unifying mechanism that orchestrates force loss across such diverse molecular targets has not been identified. We showed that correcting defective hydrogen sulfide (H2S) signaling in mdx muscle prevented ECC force loss. We also showed that the cysteine proteome of skeletal muscle functioned as a redox buffer in WT and mdx muscle during ECCs, but that buffer capacity in mdx muscle was significantly compromised by elevated basal protein oxidation. Finally, chemo-proteomic data suggested that H2S protected several proteins central to muscle contraction against irreversible oxidation through persulfidation-based priming. Our results support a unifying, redox-based mechanism of ECC force loss in mdx muscle.
Authors
W. Michael Southern, Erynn E. Johnson, Elizabeth K. Fasbender, Katherine S. Fallon, Courtney L. Cavazos, Dawn A. Lowe, George G. Rodney, James M. Ervasti
×Abstract
Tumor-initiating cells (TICs) play a key role in cancer progression and immune escape. However, how TICs evade immune elimination remains poorly characterized. Combining single-cell RNA-Seq (scRNA-Seq), dual-recombinase–based lineage tracing, and other approaches, we identified a WNT-activated subpopulation of malignant cells that act as TICs in vivo. We found intensive reciprocal interactions between TICs and immune-regulatory tumor-associated macrophages (Reg-TAMs) via growth arrest–specific 6/AXL receptor tyrosine kinase/MER proto-oncogene, tyrosine kinase (GAS6/AXL/MERTK) signaling pathways, which facilitated the immune escape of TICs. In this study, we used chemical inhibitors and Axl/Mertk conditional double-KO (cDKO) mice to demonstrate that inhibiting the interaction between TIC-derived GAS6 and AXL/MERTK in Reg-TAMs reactivated antitumor immune responses. We identified CCL8 as a critical mediator of the GAS6/AXL/MERTK pathway, primarily by inhibiting Treg infiltration into the tumor. Furthermore, the AXL/MERTK signaling blockade sensitized tumor cells to anti–programmed cell death 1 (anti–PD-1) treatment. Thus, we elucidated a detailed mechanism by which TICs evade tumor immunity, providing insights into strategies to eradicate TICs that escape conventional immunotherapy.
Authors
Shuang Chen, Chensong Huang, Kang Li, Maosheng Cheng, Caihua Zhang, Jianqi Xiong, Guoli Tian, Ruoxing Zhou, Rongsong Ling, Xiaochen Wang, Gan Xiong, Zhihui Zhang, Jieyi Ma, Yan Zhu, Bin Zhou, Liang Peng, Zhenwei Peng, Heping Li, Demeng Chen
×Abstract
The bone marrow (BM) niche is critical in regulating hematopoiesis, and sexual dimorphism and its underlying mechanism in the BM niche and its impact on hematopoiesis are not well understood. We show that male mice exhibited a higher abundance of leptin-receptor–expressing mesenchymal stromal cells (LepR-MSCs) compared with female mice. Sex-mismatched coculture and BM transplantation showed that the male BM niche provided superior support for in vitro colony formation and in vivo hematopoietic engraftment. The cotransplantation of male stromal cells significantly enhanced engraftment in female recipients. Single-cell RNA-seq revealed that the lower expression of the X-linked lysine H3K4 demethylase, Kdm5c, in male MSCs led to the increased expression of Cxcl12. In MSC-specific Kdm5c-KO mouse model, the reduction of KDM5C in female MSCs enhanced MSC quantity and function, ultimately improving engraftment to the male level. Kdm5c thus plays a role in driving sexual dimorphism in the BM niche and hematopoietic regeneration. Our study unveils a sex-dependent mechanism governing the BM niche regulation and its impact on hematopoietic engraftment. The finding offers potential implications for enhancing BM transplantation efficacy in clinical settings by harnessing the resource of male MSCs or targeting Kdm5c.
Authors
Xiaojing Cui, Liming Hou, Bowen Yan, Jinpeng Liu, Cuiping Zhang, Pinpin Sui, Sheng Tong, Larry Luchsinger, Avital Mendelson, Daohong Zhou, Feng-chun Yang, Hui Zhong, Ying Liang
×Abstract
Dravet syndrome (DS) is a developmental and epileptic encephalopathy (DEE) that begins in the first year of life. While most cases of DS are caused by variants in SCN1A, variants in SCN1B, encoding voltage-gated sodium channel β1 subunits, are also linked to DS or to the more severe early infantile DEE. Both disorders fall under the OMIM term DEE52. Scn1b-null mice model DEE52, with spontaneous generalized seizures and death in 100% of animals in the third postnatal week. Scn1b-null cortical parvalbumin-positive interneurons and pyramidal neurons are hypoexcitable. The goal of this study was to develop a proof-of-principle gene replacement strategy for DEE52. We tested an adeno-associated viral vector encoding β1 subunit cDNA (AAV-Navβ1) in Scn1b-null mice. We demonstrated that AAV-Navβ1 drives β1 protein expression in excitatory and inhibitory neurons in mouse brains. Bilateral intracerebroventricular administration of AAV-Navβ1 in Scn1b-null mice at postnatal day 2 (P2), but not at P10, reduced spontaneous seizure severity and duration, prolonged lifespan, prevented hyperthermia-induced seizures, and restored cortical neuron excitability. AAV-Navβ1 administration to WT mice resulted in β1 overexpression in brain but no obvious adverse effects. This work lays the foundation for future development of a gene therapeutic strategy for patients with SCN1B-linked DEE.
Authors
Chunling Chen, Yukun Yuan, Heather A. O’Malley, Robert Duba-Kiss, Yan Chen, Karl Habig, Yosuke Niibori, Samantha L. Hodges, David R. Hampson, Lori L. Isom
×Abstract
The biology centered around the TGF-β type I receptor activin receptor-like kinase (ALK) 1 (encoded by ACVRL1) has been almost exclusively based on its reported endothelial expression pattern since its first functional characterization more than 2 decades ago. Here, in efforts to better define the therapeutic context in which to use ALK1 inhibitors, we uncover a population of tumor-associated macrophages (TAMs) that, by virtue of their unanticipated Acvrl1 expression, are effector targets for adjuvant antiangiogenic immunotherapy in mouse models of metastatic breast cancer. The combinatorial benefit depended on ALK1-mediated modulation of the differentiation potential of bone marrow–derived granulocyte-macrophage progenitors, the release of CD14+ monocytes into circulation, and their eventual extravasation. Notably, ACVRL1+ TAMs coincided with an immunosuppressive phenotype and were overrepresented in human cancers progressing on therapy. Accordingly, breast cancer patients with a prominent ACVRL1hi TAM signature exhibited a significantly shorter survival. In conclusion, we shed light on an unexpected multimodal regulation of tumorigenic phenotypes by ALK1 and demonstrate its utility as a target for antiangiogenic immunotherapy.
Authors
Mehrnaz Safaee Talkhoncheh, Jonas Sjölund, Paulina Bolivar, Ewa Kurzejamska, Eugenia Cordero, Teia Vallès Pagès, Sara Larsson, Sophie Lehn, Gustav Frimannsson, Viktor Ingesson, Sebastian Braun, Jessica Pantaleo, Clara Oudenaarden, Martin Lauss, R. Scott Pearsall, Göran Jönsson, Charlotte Rolny, Matteo Bocci, Kristian Pietras
×Abstract
Hematopoietic stem cells (HSCs) rely on self-renewal to sustain stem cell potential and undergo differentiation to generate mature blood cells. Mitochondrial fatty acid β-oxidation (FAO) is essential for HSC maintenance. However, the role of carnitine palmitoyl transferase 1a (CPT1A), a key enzyme in FAO, remains unclear in HSCs. Using a Cpt1a hematopoiesis-specific conditional-KO (Cpt1aΔ/Δ) mouse model, we found that loss of Cpt1a led to HSC defects, including loss of HSC quiescence and self-renewal and increased differentiation. Mechanistically, we found that loss of Cpt1a resulted in elevated levels of mitochondrial respiratory chain complex components and their activity, as well as increased ATP production and accumulation of mitochondrial ROS in HSCs. Taken together, this suggests hyperactivation of mitochondria and metabolic rewiring via upregulated glucose-fueled oxidative phosphorylation (OXPHOS). In summary, our findings demonstrate an essential role for Cpt1a in HSC maintenance and provide insight into the regulation of mitochondrial metabolism via control of the balance between FAO and glucose-fueled OXPHOS.
Authors
Jue Li, Jie Bai, Vincent T. Pham, Michihiro Hashimoto, Maiko Sezaki, Qili Shi, Qiushi Jin, Chenhui He, Amy Armstrong, Tian Li, Mingzhe Pan, Shujun Liu, Yu Luan, Hui Zeng, Paul R. Andreassen, Gang Huang
×Abstract
The role of macrophages (MΦs) remains incompletely understood in kidney injury and repair. The plasticity of MΦs offers an opportunity to polarize them toward mediating injury resolution in both native and transplanted kidneys undergoing ischemia and/or rejection. Here, we show that infiltrating kidney MΦs augmented their own allograft inflammatory factor 1 (AIF-1) expression after injury. Aif1 genetic deletion led to MΦ polarization toward a reparative phenotype while halting the development of kidney fibrosis. The enhanced repair was mediated by higher levels of antiinflammatory and proregenerative markers, leading to a reduction in cell death and an increase in proliferation of kidney tubular epithelial cells after ischemia followed by reperfusion injury (I/RI). Adoptive transfer of Aif1–/– MΦs into Aif1+/+ mice conferred protection against I/RI. Conversely, depletion of MΦs reversed the tissue-reparative effects in Aif1–/– mice. We further demonstrated increased expression of AIF-1 in human kidney biopsies from native kidneys with acute kidney injury or chronic kidney disease, as well as in biopsies from kidney allografts undergoing acute or chronic rejection. We conclude that AIF-1 is a MΦ marker of renal inflammation, and its targeting uncouples MΦ reparative functions from profibrotic functions. Thus, therapies inhibiting AIF-1 when ischemic injury is inevitable have the potential to reduce the global burden of kidney disease.
Authors
Irma Husain, Holly Shah, Collin Z. Jordan, Naveen R. Natesh, Olivia K. Fay, Yanting Chen, Jamie R. Privratsky, Hiroki Kitai, Tomokazu Souma, Shyni Varghese, David N. Howell, Edward B. Thorp, Xunrong Luo
×Abstract
BACKGROUND Rapid diagnosis to facilitate urgent intervention is critical for treatment of acute spinal cord injury (SCI). We hypothesized that a multi-analyte blood biomarker would support point-of-care SCI diagnosis, correlate with injury severity, and predict long-term neurologic outcomes.METHODS Droplet digital PCR (ddPCR) assays were designed to amplify differentially hypomethylated genomic loci in spinal cord tissue. An optimized ddPCR assay was applied to cell-free DNA (cfDNA) from plasma samples collected from prospectively enrolled acute SCI patients. Targeted proteomic profiling was also performed. Spinal cord–derived cfDNA and plasma proteins were tested for their association with SCI and ability to predict conversion in American Spinal Injury Association (ASIA) score at 6 months.RESULTS A bespoke ddPCR assay detected spinal cord–derived cfDNA in plasma of 50 patients with acute SCI (AUC: 0.89, 95% CI 0.83–0.95, P < 0.0001). Levels of cfDNA were highest in patients with the most severe injury, i.e., ASIA A, compared with those with ASIA B (P = 0.04), ASIA C (P = 0.009), and ASIA D injuries (P < 0.001). Dimensionality reduction identified 4 candidate proteins (FABP3, REST, IL-6, NF-H) that were integrated with spinal cord–derived cfDNA to derive the Spinal Cord Injury Index (SCII), which has high sensitivity and specificity for SCI diagnosis (AUC: 0.91, 95% CI 0.82–0.99, P < 0.0001), correlates with injury severity (P < 0.0001), and predicts 6-month neurologic improvement (AUC: 0.77, 95% CI 0.61–0.93, P = 0.006).CONCLUSION The detection of spinal cord–derived cfDNA and plasma protein alterations as part of a multi-analyte blood test can inform SCI diagnosis and prognosis.FUNDING North American Spine Society Young Investigator Award; Morton Cure Paralysis Fund.
Authors
Tej D. Azad, Kathleen R. Ran, Joshua D. Materi, Divyaansh Raj, Timour Al-Khindi, Sameer Gabbita, Marvin Li, Elizabeth T. Wang, A. Karim Ahmed, Megan Parker, Anita L. Kalluri, Daniel Lubelski, Christopher M. Jackson, Daniel M. Sciubba, Jon D. Weingart, Ali Bydon, Timothy F. Witham, David W. Nauen, Srinivasan Yegnasubramanian, Nicholas Theodore, Chetan Bettegowda
×Abstract
Understanding the complexity of the tumor microenvironment is vital for improving immunotherapy outcomes. Here, we report that the T cell costimulatory molecule OX40 was highly expressed in tumor endothelial cells (ECs) and was negatively associated with the prognosis of patients, which is irrelevant to T cell activation. Analysis of conditional OX40 loss- and gain-of-function transgenic mice showed that OX40 signal in ECs counteracted the antitumor effects produced in T cells by promoting angiogenesis. Mechanistically, leucine-rich repeat–containing GPCR5 (Lgr5+ ) cancer stem cells induced OX40 expression in tumor ECs via EGF/STAT3 signaling. Activated OX40 interacted with Spns lysolipid transporter 2 (Spns2), obstructing the export of sphingosine 1-phosphate (S1P) and resulting in S1P intracellular accumulation. Increased S1P directly bound to Yes 1–associated protein (YAP), disrupting its interaction with large tumor suppressor kinase 1 (LATS1) and promoting YAP nuclear translocation. Finally, the YAP inhibitor verteporfin enhanced the antitumor effects of the OX40 agonist. Together, these findings reveal an unexpected protumor role of OX40 in ECs, highlighting the effect of nonimmune cell compartments on immunotherapy.
Authors
Baoyu He, Rou Zhao, Baogui Zhang, Hongli Pan, Jilan Liu, Lunhua Huang, Yingying Wei, Dong Yang, Jing Liang, Mingyi Wang, Mingsheng Zhao, Sen Wang, Fengyun Dong, Junfeng Zhang, Yanhua Zhang, Xu Zhang, Xiao Zhang, Guanjun Dong, Huabao Xiong, Qingli Bie, Bin Zhang
×Abstract
The histopathological neurons in the brain tissue of drug-resistant epilepsy exhibit aberrant cytoarchitecture and imbalanced synaptic circuit function. However, the gene expression changes of these neurons remain unknown, making it difficult to determine the diagnosis or to dissect the mechanism of drug-resistant epilepsy. By integrating whole-cell patch clamp recording and single-cell RNA-seq approaches, we identified a transcriptionally distinct subset of cortical pyramidal neurons. These neurons highly expressed genes CDKN1A (P21), CCL2, and NFKBIA, which associate with mTOR pathway, inflammatory response, and cellular senescence. We confirmed the expression of senescent marker genes in a subpopulation of cortical pyramidal neurons with enlarged soma size in the brain tissue of drug-resistant epilepsy. We further revealed the expression of senescent cell markers P21, P53, COX2, γ-H2AX, and β-Gal, and reduction of nuclear integrity marker Lamin B1 in histopathological neurons in the brain tissue of patients with drug-resistant epilepsy with different pathologies, but not in control brain tissue with no history of epilepsy. Additionally, chronic, but not acute, epileptic seizures induced senescent marker expression in cortical neurons in mouse models of drug-resistant epilepsy. These results provide important molecular markers for histopathological neurons and what we believe to be new insights into the pathophysiological mechanisms of drug-resistant epilepsy.
Authors
Qianqian Ge, Jiachao Yang, Fei Huang, Xinyue Dai, Chao Chen, Jingxin Guo, Mi Wang, Mengyue Zhu, Yijie Shao, Yuxian Xia, Yu Zhou, Jieqiao Peng, Suixin Deng, Jiachen Shi, Yiqi Hu, Huiying Zhang, Yi Wang, Xiaoqun Wang, Xiao-Ming Li, Zhong Chen, Yousheng Shu, Jun-Ming Zhu, Jianmin Zhang, Ying Shen, Shumin Duan, Shengjin Xu, Li Shen, Jiadong Chen
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Abstract
Although refrigerated storage slows the metabolism of volunteer donor RBCs, which is essential in transfusion medicine, cellular aging still occurs throughout this in vitro process. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSEhigh) and morphologically-normal RBCs (CFSElow), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSEhigh RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSEhigh RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSEhigh RBC membranes. CFSEhigh RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen perfusion ex vivo. Conversely, molecular, cellular, and circulatory properties of long-stored CFSElow RBCs resembled those of short-stored RBCs. CFSEhigh RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in these storage-induced senescent RBCs targeted for clearance.
Authors
Sandy Peltier, Mickaël Marin, Monika Dzieciatkowska, Michaël Dussiot, Micaela Kalani Roy, Johanna Bruce, Louise Leblanc, Youcef Hadjou, Sonia Georgeault, Aurélie Fricot, Camille Roussel, Daniel Stephenson, Madeleine Casimir, Abdoulaye Sissoko, François Paye, Safi Dokmak, Papa Alioune Ndour, Philippe Roingeard, Emilie-Fleur Gautier, Steven L. Spitalnik, Olivier Hermine, Pierre A. Buffet, Angelo D’Alessandro, Pascal Amireault
Abstract
Osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) has been recognized as the principal mechanism underlying vascular calcification (VC). Runt-related transcription factor 2 (RUNX2) in VSMCs plays a pivotal role because it constitutes an essential osteogenic transcription factor for bone formation. As a key DNA demethylation enzyme, ten-eleven translocation 2 (TET2) is crucial in maintaining the VSMC phenotype. However, whether TET2 involves in VC progression remains elusive. Here we identified a substantial downregulation of TET2 in calcified human and mouse arteries, as well as human primary VSMCs. In vitro gain- and loss-of function experiments demonstrated TET2 regulated VC. Subsequently, in vivo knockdown of TET2 significantly exacerbated VC in both vitamin D3 and adenine-diet-induced chronic kidney disease (CKD) mice models. Mechanistically, TET2 binds to and suppresses the activity of the P2 promoter within the RUNX2 gene, whereas an enzymatic loss-of-function mutation of TET2 has a comparable effect. Furthermore, TET2 forms a complex with histone deacetylases 1/2 (HDAC1/2 ) to deacetylate H3K27ac on the P2 promoter, thereby inhibiting its transcription. Moreover, SNIP1 is indispensable for TET2 to interact with HDAC1/2 to exert inhibitory effect on VC, and knockdown of SNIP1 accelerated VC in mice. Collectively, our findings imply that TET2 might serve as a potential therapeutic target for VC.
Authors
Dayu He, Jianshuai Ma, Ziting Zhou, Yanli Qi, Yaxin Lian, Feng Wang, Huiyong Yin, Huanji Zhang, Tingting Zhang, Hui Huang
Abstract
Biological targeting is crucial for effective cancer treatment with reduced toxicity but is limited by the availability of tumor surface markers. To overcome this, we developed a nanoparticle-based, Tumor-specific suRfACE maRker-independent (TRACER) targeting approach. Utilizing the unique biodistribution properties of nanoparticles, we encapsulated Ac4ManNAz to selectively label tumors with azide reactive groups. Surprisingly, while NP-delivered Ac4ManNAz was cleared by the liver, it did not label macrophages, potentially reducing off-target effects. To exploit this tumor-specific labeling, we functionalized anti-4-1BB antibodies with dibenzocyclooctyne (DBCO) to target azide-labeled tumor cells and activate the immune response. In syngeneic B16F10 melanoma and orthotopic 4T1 breast cancer models, TRACER enhanced anti-4-1BB’s therapeutic efficacy, increasing median survival time. Immunofluorescence analyses revealed increased tumor infiltration of CD8+ T and NK cells with TRACER. Importantly, TRACER reduced hepatotoxicity associated with anti-4-1BB, resulting in normal serum ALT and AST levels and decreased CD8+ T cell infiltration in the liver. Quantitative analysis confirmed a 4.5-fold higher tumor-to-liver ratio of anti-4-1BB accumulation with TRACER compared to conventional anti-4-1BB antibodies. Our work provides a promising approach for developing targeted cancer therapies that circumvent limitations imposed by the paucity of tumor-specific markers, potentially improving efficacy and reducing off-target effects to overcome liver toxicity associated with anti-4-1BB.
Authors
Hyesun Hyun, Bo Sun, Mostafa Yazdimamaghani, Albert Wielgus, Yue Wang, Stephanie Ann Montgomery, Tian Zhang, Jianjun Cheng, Jonathan S. Serody, Andrew Z. Wang
Abstract
Phosphorylation of Smad3 is a critical mediator of TGF-β signaling, which plays an important role in regulating innate immune responses. However, whether Smad3 activation can be regulated in innate immune cells in TGF-β-independent contexts remains poorly understood. Here, we show that Smad3 is activated through the phosphorylation of its C-terminal residues (pSmad3C) in murine and human macrophages in response to bacterial and viral ligands, which is mediated by Activin A in a TGF-β independent manner. Specifically, infectious ligands, such as LPS, induced secretion of Activin A through the transcription factor STAT5 in macrophages, and Activin A signaling in turn activated pSmad3C. This Activin A-Smad3 axis controlled the mitochondrial ATP production and ATP conversion into adenosine by CD73 in macrophages, enforcing an anti-inflammatory mechanism. Consequently, mice with a deletion of Activin A receptor 1b specifically in macrophages (Acvr1bf/f-Lyz2cre) succumbed more to sepsis due to uncontrolled inflammation and exhibited exacerbated skin disease in a mouse model of imiquimod-induced psoriasis. Thus, we have revealed a previously unrecognized natural brake to inflammation in macrophages that occurs through the activation of Smad3 in an Activin A-dependent manner.
Authors
Thierry Gauthier, Yun-Ji Lim, Wenwen Jin, Na Liu, Liliana C. Patiño, Weiwei Chen, James Warren, Daniel Martin, Robert J. Morell, Gabriela S. Dveksler, Gloria H. Su, WanJun Chen
Abstract
Multiple sclerosis (MS) is a complex genetically mediated autoimmune disease of the central nervous system where anti-CD20-mediated B cell depletion is remarkably effective in the treatment of early disease. While previous studies investigated the effect of B cell depletion on select immune cell subsets using flow cytometry-based methods, the therapeutic impact on patient immune landscape is unknown. In this study, we explored how B cell depleting therapies modulate the immune landscape using single-cell RNA sequencing (scRNAseq). We demonstrate that B cell depletion leads to cell type-specific changes in the abundance and function of CSF macrophages and peripheral blood monocytes. Specifically, a CSF-specific macrophage population with an anti-inflammatory transcriptomic signature and peripheral CD16+ monocytes increased in frequency post-B cell depletion. This was accompanied by increases in TNFα messenger RNA and protein in monocytes post-B cell depletion, consistent with the finding that anti-TNFα treatment exacerbates autoimmune activity in MS. In parallel, B cell depletion induced changes in peripheral CD4+ T cell populations, including increases in the frequency of TIGIT+ regulatory T cells and marked decreases in the frequency of myelin peptide loaded-tetramer binding CD4+ T cells. Collectively, this study provides an exhaustive transcriptomic map of immunological changes, revealing different cell-type specific reprogramming as a result of B cell depletion treatment in MS.
Authors
Jessica Wei, Jeonghyeon Moon, Yoshiaki Yasumizu, Le Zhang, Khadir Raddassi, Nicholas C. Buitrago-Pocasangre, M. Elizabeth Deerhake, Nicolas Strauli, Chun-Wei Chen, Ann Herman, Rosetta Pedotti, Catarina Raposo, Isaiah Yim, Jenna L. Pappalardo, Erin E. Longbrake, Tomokazu S. Sumida, Pierre-Paul Axisa, David A. Hafler
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Series edited by Eugene B. Chang
Microbiome in Health and Disease
Series edited by Eugene B. Chang
Host-microbe interactions are increasingly recognized for their roles in promoting health as well as in disease pathogenesis. This in-progress series was designed by current JCI Associate Editor Eugene B. Chang to highlight recent advances and challenges in understanding the human microbiome across different organ systems as well as the outlook for microbiome-targeted therapeutics.
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ISSN: 0021-9738 (print), 1558-8238 (online)