Issue published March 17, 2025 Previous issue
- Volume 135, Issue 6
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On the cover: RNase L restrains regeneration in response to tissue injury
Kirby et al. show that the oligoadenylate synthetase (OAS)/RNase L pathway, which regulates the innate immune response to viral RNA, represses wound healing and epithelial regeneration. Loss of Rnase L or pharmacological inhibition of downstream signaling enhances regenerative capacity in mice. The cover shows Xenium spatial transcriptomics of Rnasel6-knockout mouse skin captured in Xenium Explorer using graph-based clustering.
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Reviews
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Abstract
Anomalies during angiogenesis can initiate the formation of arteriovenous malformations (AVMs), characterized by aberrant connections between arteries and veins and fast lesional blood flow. These anomalies can manifest anywhere in the body, including the brain, and they typically appear at birth and evolve alongside growth of the individual. Depending on their location and size, AVMs can induce progressive deformation, chronic pain, functional impairment, and ulceration and pose life-threatening risks such as hemorrhage and organ dysfunction. The primary treatment modalities entail surgical intervention or embolization followed by surgery. However, these approaches are often challenging and seldom offer definitive resolution. In addition, inadequately performed surgery may trigger angiogenic rebound, fostering AVM recurrence. Advancements in comprehending the molecular pathways underlying AVMs have sparked interest in repurposing targeted therapies initially devised for cancer treatment. The first results are promising, giving new hope to the patients affected with these often devastating and debilitating lesions, the management of which presents major clinical challenges.
Authors
Julien Coulie, Emmanuel Seront, Miikka Vikkula, Laurence M. Boon
×Abstract
In mammalian cells cholesterol can be synthesized endogenously or obtained exogenously through lipoprotein uptake. Plasma membrane (PM) is the primary intracellular destination for both sources of cholesterol, and maintaining appropriate membrane cholesterol levels is critical for cellular viability. The endoplasmic reticulum (ER) acts as a cellular cholesterol sensor, regulating synthesis in response to cellular needs and determining the metabolic fates of cholesterol. Upon reaching the ER, cholesterol can be esterified to facilitate its incorporation into lipoproteins and lipid droplets or converted into other molecules such as bile acids and oxysterols. In recent years, it has become clear that the intracellular redistribution of lipids, including cholesterol, is critical for the regulation of various biological processes. This Review highlights physiology and mechanisms of nonvesicular (protein-mediated) intracellular cholesterol trafficking, with a focus on the role of Aster proteins in PM to ER cholesterol transport.
Authors
Alessandra Ferrari, Peter Tontonoz
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Acute kidney injury (AKI) encompasses pathophysiology ranging from glomerular hypofiltration to tubular cell injury and outflow obstruction. This Review will focus on the tubulointerstitial processes that underlie most cases of AKI. Tubular epithelial cell (TEC) injury can occur via distinct insults, including ischemia, nephrotoxins, sepsis, and primary immune-mediated processes. Following these initial insults, tubular cells can activate survival and repair responses or they can develop mitochondrial dysfunction and metabolic reprogramming, cell-cycle arrest, and programmed cell death. Developing evidence suggests that the fate of individual tubular cells to survive and proliferate or undergo cell death or senescence is frequently determined by a biphasic immune response with initial proinflammatory macrophage, neutrophil, and lymphocyte infiltration exacerbating injury and activating programmed cell death, while alternatively activated macrophages and specific lymphocyte subsets subsequently modulate inflammation and promote repair. Functional recovery requires that this reparative phase supports proteolytic degradation of tubular casts, proliferation of surviving TECs, and restoration of TEC differentiation. Incomplete resolution or persistence of inflammation can lead to failed tubular repair, fibrosis, and chronic kidney disease. Despite extensive research in animal models, translating preclinical findings to therapies remains challenging, emphasizing the need for integrated multiomic approaches to advance AKI understanding and treatment.
Authors
Megan L. Baker, Lloyd G. Cantley
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Commentaries
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Abstract
Approximately one-quarter of the global population is estimated to be infected with Mycobacterium tuberculosis. New developments in vaccine design and therapeutics are urgently needed, particularly in the face of multidrug-resistant tuberculosis (TB). In this issue of the JCI, Sakai and colleagues used a multidisciplinary approach to determine that trehalose-6-monomycolate (TMM), a mycobacterial cell wall lipid, serves as a T cell antigen presented by CD1b. CD1b-TMM–specific T cells were characterized by conserved T cell receptor features and were present at elevated frequencies in individuals with active TB disease. These findings highlight the dual role of TMM in stimulating both innate and adaptive immunity and broaden our understanding of CD1-mediated lipid recognition by unconventional T cells.
Authors
Catarina F. Almeida, Jennifer A. Juno
×Abstract
Inherited bone marrow failure syndromes (IBMFSs) encompass a diverse group of hematological disorders characterized by a progressive single-lineage cytopenia or pancytopenia. Despite their heterogeneity, these syndromes often result from genetic errors affecting key biological mechanisms, including telomere maintenance, DNA repair and chromosomal stability, and ribosome assembly, generally leading to accelerated apoptosis of hematopoietic cells. Nevertheless, a genetic diagnosis remains elusive in more than half of the cases. The increased risk of myelodysplastic syndrome (MDS), acute leukemia, and solid tumors associated with IBMFS frequently prompts early hematopoietic stem cell transplantation (HSCT). In this issue of the JCI, Garrigue, Kermasson, and colleagues identified a homozygous variant in Oncostatin M (OSM) in 3 children from a consanguineous family presenting with IBMFS characterized by profound anemia, thrombocytopenia, and neutropenia. The findings suggest that the loss-of-function OSM variant affected hematopoietic stem cell function through changes to the bone marrow microenvironment (BMM).
Authors
Selket Delafontaine, Isabelle Meyts
×Abstract
Pulmonary hypertension (PH) encompasses a heterogenous group of disorders with the common feature of increased pulmonary arterial pressures. Patients with PH associated with lung disease and/or hypoxia undergo immune-mediated vascular remodeling that includes thickening of the muscular layer surrounding arteries and arterioles. In this issue of the JCI, Kumar and colleagues examined the role of interstitial macrophages in a model of high-altitude PH. Resident interstitial macrophages increased, proliferated, and expressed CCL2, a monocyte chemoattractant ligand. There was also a rise in CCR2+ macrophages expressing thrombospondin-1, which is known to activate vascular remodeling through TGF-β. Blocking monocyte recruitment partially reduced hypoxic PH, and corticosteroid treatment effectively reduced CCL2 expression and CCR2+ monocyte recruitment. Further, plasma samples collected from individuals ascending from low to high altitudes showed increased thrombospondin-1 and TGF-β levels, which were reduced with dexamethasone. These findings reveal interstitial macrophage populations as potential therapeutic targets in hypoxic PH.
Authors
Edda Spiekerkoetter
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Research Letter
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Abstract
Authors
Evi J.C. Koene, Amée M. Buziau, David Cassiman, Timothy M. Cox, Judith Bons, Jean L.J.M. Scheijen, Casper G. Schalkwijk, Steven J.R. Meex, Aditi R. Saxena, William P. Esler, Vera B. Schrauwen-Hinderling, Patrick Schrauwen, Martijn C.G.J. Brouwers
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Research Articles
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Abstract
Mammalian injury responses are predominantly characterized by fibrosis and scarring rather than functional regeneration. This limited regenerative capacity in mammals could reflect a loss of proregeneration programs or active suppression by genes functioning akin to tumor suppressors. To uncover programs governing regeneration in mammals, we screened transcripts in human participants following laser rejuvenation treatment and compared them with mice with enhanced wound-induced hair neogenesis (WIHN), a rare example of mammalian organogenesis. We found that Rnasel–/– mice exhibit an increased regenerative capacity, with elevated WIHN through enhanced IL-36α. Consistent with RNase L’s known role to stimulate caspase-1, we found that pharmacologic inhibition of caspases promoted regeneration in an IL-36–dependent manner in multiple epithelial tissues. We identified a negative feedback loop, where RNase L–activated caspase-1 restrains the proregenerative dsRNA-TLR3 signaling cascade through the cleavage of toll-like adaptor protein TRIF. Through integrated single-cell RNA-seq and spatial transcriptomic profiling, we confirmed OAS & IL-36 genes to be highly expressed at the site of wounding and elevated in Rnasel–/– mouse wounds. This work suggests that RNase L functions as a regeneration repressor gene, in a functional trade off that tempers immune hyperactivation during viral infection at the cost of inhibiting regeneration.
Authors
Charles S. Kirby, Nasif Islam, Eric Wier, Martin P. Alphonse, Evan Sweren, Gaofeng Wang, Haiyun Liu, Dongwon Kim, Ang Li, Sam S. Lee, Andrew M. Overmiller, Yingchao Xue, Sashank Reddy, Nathan K. Archer, Lloyd S. Miller, Jianshi Yu, Weiliang Huang, Jace W. Jones, Sooah Kim, Maureen A. Kane, Robert H. Silverman, Luis A. Garza
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Hypoxia is a major cause of pulmonary hypertension (PH) worldwide, and it is likely that interstitial pulmonary macrophages contribute to this vascular pathology. We observed in hypoxia-exposed mice an increase in resident interstitial macrophages, which expanded through proliferation and expressed the monocyte recruitment ligand CCL2. We also observed an increase in CCR2+ macrophages through recruitment, which express the protein thrombospondin-1, which functionally activates TGF-β to cause vascular disease. Blockade of monocyte recruitment with either CCL2-neutralizing antibody treatment or CCR2 deficiency in the bone marrow compartment suppressed hypoxic PH. These data were supported by analysis of plasma samples from humans who traveled from low (225 m) to high (3500 m) elevation, revealing an increase in thrombospondin-1 and TGF-β expression following ascent, which was blocked by dexamethasone prophylaxis. In the hypoxic mouse model, dexamethasone prophylaxis recapitulated these findings by mechanistically suppressing CCL2 expression and CCR2+ monocyte recruitment. These data suggest a pathologic cross talk between 2 discrete interstitial macrophage populations, which can be therapeutically targeted.
Authors
Rahul Kumar, Kevin Nolan, Biruk Kassa, Neha Chanana, Tsering Palmo, Kavita Sharma, Kanika Singh, Claudia Mickael, Dara Fonseca Balladares, Julia Nilsson, Amit Prabhakar, Aastha Mishra, Michael H. Lee, Linda Sanders, Sushil Kumar, Ari B. Molofsky, Kurt R. Stenmark, Dean Sheppard, Rubin M. Tuder, Mohit D. Gupta, Tashi Thinlas, Qadar Pasha, Brian B. Graham
×Abstract
Fibrosis of the lower abdominal muscle (LAM) contributes to muscle weakening and inguinal hernia formation, an ailment that affects a noteworthy 50% of men by age 75 and necessitates surgical correction as the singular therapy. Despite its prevalence, the mechanisms driving LAM fibrosis and hernia development remain poorly understood. Using a humanized mouse model that replicates the elevated skeletal muscle tissue estrogen concentrations seen in aging men, we identified estrogen receptor-α (ESR1) as a key driver of LAM fibroblast proliferation, extracellular matrix deposition, and hernia formation. Fibroblast-specific ESR1 ablation effectively prevented muscle fibrosis and herniation, while pharmacological ESR1 inhibition with fulvestrant reversed hernias and restored normal muscle architecture. Multiomics analyses of in vitro LAM fibroblasts from humanized mice unveiled an estrogen/ESR1-mediated activation of a distinct profibrotic cistrome and gene expression signature, concordant with observations in inguinal hernia tissues in human males. Our findings hold significant promise for prospective medical interventions targeting fibrotic conditions and present non-surgical avenues for addressing inguinal hernias.
Authors
Tanvi Potluri, Tianming You, Ping Yin, John Coon V, Jonah J. Stulberg, Yang Dai, David J. Escobar, Richard L. Lieber, Hong Zhao, Serdar E. Bulun
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Fibrosis is the final common pathway leading to end-stage chronic kidney disease (CKD). However, the function of protein palmitoylation in renal fibrosis and the underlying mechanisms remain unclear. In this study, we observed that expression of the palmitoyltransferase ZDHHC18 was significantly elevated in unilateral ureteral obstruction (UUO) and folic acid–induced (FA-induced) renal fibrosis mouse models and was significantly upregulated in fibrotic kidneys of patients with CKD. Functionally, tubule-specific deletion of ZDHHC18 attenuated tubular epithelial cells’ partial epithelial-mesenchymal transition (EMT) and then reduced the production of profibrotic cytokines and alleviated tubulointerstitial fibrosis. In contrast, ZDHHC18 overexpression exacerbated progressive renal fibrosis. Mechanistically, ZDHHC18 catalyzed the palmitoylation of HRAS, which was pivotal for its translocation to the plasma membrane and subsequent activation. HRAS palmitoylation promoted downstream phosphorylation of MEK/ERK and further activated Ras-responsive element–binding protein 1 (RREB1), enhancing SMAD binding to the Snai1 cis-regulatory regions. Taken together, our findings suggest that ZDHHC18 plays a crucial role in renal fibrogenesis and represents a potential therapeutic target for combating kidney fibrosis.
Authors
Di Lu, Gulibositan Aji, Guanyu Li, Yue Li, Wenlin Fang, Shuai Zhang, Ruiqi Yu, Sheng Jiang, Xia Gao, Yuhang Jiang, Qi Wang
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Oncostatin M (OSM) is a cytokine with the unique ability to interact with both the OSM receptor (OSMR) and the leukemia inhibitory factor receptor (LIFR). On the other hand, OSMR interacts with IL31RA to form the interleukin-31 receptor. This intricate network of cytokines and receptors makes it difficult to understand the specific function of OSM. While monoallelic loss-of-function (LoF) mutations in OSMR underlie autosomal dominant familial primary localized cutaneous amyloidosis, the in vivo consequences of human OSM deficiency have never been reported so far. Here, we identified 3 young individuals from a consanguineous family presenting with inherited severe bone marrow failure syndromes (IBMFS) characterized by profound anemia, thrombocytopenia, and neutropenia. Genetic analysis revealed a homozygous 1 base-pair insertion in the sequence of OSM associated with the disease. Structural and functional analyses showed that this variant causes a frameshift that replaces the C-terminal portion of OSM, which contains the FxxK motif that interacts with both OSMR and LIFR, with a neopeptide. The lack of detection and signaling of the mutant OSM suggests a LoF mutation. Analysis of zebrafish models further supported the role of the OSM/OSMR signaling in erythroid progenitor proliferation and neutrophil differentiation. Our study provides the previously uncharacterized and unexpectedly limited in vivo consequence of OSM deficiency in humans.
Authors
Alexandrine Garrigue, Laëtitia Kermasson, Sandrine Susini, Ingrid Fert, Christopher B. Mahony, Hanem Sadek, Sonia Luce, Myriam Chouteau, Marina Cavazzana, Emmanuelle Six, Marie-Caroline Le Bousse-Kerdilès, Adrienne Anginot, Jean-Baptiste Souraud, Valérie Cormier-Daire, Marjolaine Willems, Anne Sirvent, Jennifer Russello, Isabelle Callebaut, Isabelle André, Julien Y. Bertrand, Chantal Lagresle-Peyrou, Patrick Revy
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Early antibody therapy can prevent severe SARS-CoV-2 infection (COVID-19). However, the effectiveness of COVID-19 convalescent plasma (CCP) therapy in treating severe COVID-19 remains inconclusive. To test a hypothesis that some CCP units are associated with a coagulopathy hazard in severe disease that offsets its benefits, we tracked 304 CCP units administered to 414 hospitalized COVID-19 patients to assess their association with the onset of unfavorable post-transfusion D-dimer trends. CCP recipients with increasing or persistently elevated D-dimer trajectories after transfusion experienced higher mortality than those whose D-dimer levels were persistently low or decreasing after transfusion. Within the CCP donor-recipient network, recipients with increasing or persistently high D-dimer trajectories were skewed toward association with a minority of CCP units. In in vitro assays, CCP from “higher-risk” units had higher cross-reactivity with the spike protein of human seasonal betacoronavirus OC43. “Higher-risk” CCP units also mediated greater Fcγ receptor IIa signaling against cells expressing SARS-CoV-2 spike compared with “lower-risk” units. This study finds that post-transfusion activation of coagulation pathways during severe COVID-19 is associated with specific CCP antibody profiles and supports a potential mechanism of immune complex–activated coagulopathy.
Authors
Svenja Weiss, Hung-Mo Lin, Eric Acosta, Natalia L. Komarova, Ping Chen, Dominik Wodarz, Ian Baine, Ralf Duerr, Ania Wajnberg, Adrian Gervais, Paul Bastard, Jean-Laurent Casanova, Suzanne A. Arinsburg, Talia H. Swartz, Judith A. Aberg, Nicole M. Bouvier, Sean T.H. Liu, Raymond A. Alvarez, Benjamin K. Chen
×Abstract
BACKGROUND Immune checkpoint blockade (ICB) is an effective treatment in a subset of patients diagnosed with head and neck squamous cell carcinoma (HNSCC); however, the majority of patients are refractory.METHODS In a nonrandomized, open-label Phase 1b clinical trial, participants with recurrent and/or metastatic (R/M) HNSCC were treated with low-dose 5-azacytidine (5-aza) daily for either 5 or 10 days in combination with durvalumab and tremelimumab after progression on ICB. The primary objective was to assess the biologically effective dose of 5-aza as determined by molecular changes in paired baseline and on-treatment tumor biopsies; the secondary objective was safety.RESULTS Thirty-eight percent (3 of 8) of participants with evaluable paired tissue samples had a greater-than 2-fold increase from baseline in IFN-γ signature and CD274 (programmed cell death protein 1 ligand, PD-L1) expression within the tumor microenvironment (TME), which was associated with increased CD8+ T cell infiltration and decreased infiltration of CD4+ T regulatory cells. The mean neutrophil-to-lymphocyte ratio (NLR) decreased by greater than 50%, from 14.2 (SD 22.6) to 6.9 (SD 5.2). Median overall survival (OS) was 16.3 months (95% CI 1.9, NA), 2-year OS rate was 24.7% (95% CI: 4.5%, 53.2%), and 58% (7 of 12) of treated participants demonstrated prolonged OS of greater than 12 months.CONCLUSION Our findings suggest that low-dose 5-aza can reprogram systemic host immune responses and the local TME to increase IFN-γ and PD-L1 expression. The increased expression of these established biomarkers correlated with prolonged OS upon ICB rechallenge.TRIAL REGISTRATION ClinicalTrials.gov NCT03019003.FUNDING NIH/NCI P01 CA240239.
Authors
Tingting Qin, Austin K. Mattox, Jean S. Campbell, Jong Chul Park, Kee-Young Shin, Shiting Li, Peter M. Sadow, William C. Faquin, Goran Micevic, Andrew J. Daniels, Robert Haddad, Christopher S. Garris, Mikael J. Pittet, Thorsten R. Mempel, Anne ONeill, Maureen A. Sartor, Sara I. Pai
×Abstract
Viral mimicry refers to the activation of innate antiviral immune responses due to the induction of endogenous retroelements (REs). Viral mimicry augments antitumor immune responses and sensitizes solid tumors to immunotherapy. Here, we found that targeting what we believe to be a novel, master epigenetic regulator, Zinc Finger Protein 638 (ZNF638), induces viral mimicry in glioblastoma (GBM) preclinical models and potentiates immune checkpoint inhibition (ICI). ZNF638 recruits the HUSH complex, which precipitates repressive H3K9me3 marks on endogenous REs. In GBM, ZNF638 is associated with marked locoregional immunosuppressive transcriptional signatures, reduced endogenous RE expression, and poor immune cell infiltration. Targeting ZNF638 decreased H3K9 trimethylation, increased REs, and activated intracellular dsRNA signaling cascades. Furthermore, ZNF638 knockdown upregulated antiviral immune programs and significantly increased PD-L1 immune checkpoint expression in diverse GBM models. Importantly, targeting ZNF638 sensitized mice to ICI in syngeneic murine orthotopic models through innate IFN signaling. This response was recapitulated in recurrent GBM (rGBM) samples with radiographic responses to checkpoint inhibition with widely increased expression of dsRNA, PD-L1, and perivascular CD8 cell infiltration, suggesting that dsRNA signaling may mediate response to immunotherapy. Finally, low ZNF638 expression was a biomarker of clinical response to ICI and improved survival in patients with rGBM and patients with melanoma. Our findings suggest that ZNF638 could serve as a target to potentiate immunotherapy in gliomas.
Authors
Deepa Seetharam, Jay Chandar, Christian K. Ramsoomair, Jelisah F. Desgraves, Alexandra Alvarado Medina, Anna Jane Hudson, Ava Amidei, Jesus R. Castro, Vaidya Govindarajan, Sarah Wang, Yong Zhang, Adam M. Sonabend, Mynor J. Mendez Valdez, Dragan Maric, Vasundara Govindarajan, Sarah R. Rivas, Victor M. Lu, Ritika Tiwari, Nima Sharifi, Emmanuel Thomas, Marcus Alexander, Catherine DeMarino, Kory Johnson, Macarena I. De La Fuente, Ruham Alshiekh Nasany, Teresa Maria Rosaria Noviello, Michael E. Ivan, Ricardo J. Komotar, Antonio Iavarone, Avindra Nath, John Heiss, Michele Ceccarelli, Katherine B. Chiappinelli, Maria E. Figueroa, Defne Bayik, Ashish H. Shah
×Abstract
The cornerstone of functional cure for chronic hepatitis B (CHB) is hepatitis B surface antigen (HBsAg) loss from blood. HBsAg is encoded by covalently closed circular DNA (cccDNA) and HBV DNA integrated into the host genome (iDNA). Nucleos(t)ide analogs (NUCs), the mainstay of CHB treatment, rarely lead to HBsAg loss, which we hypothesized was due to continued iDNA transcription despite decreased cccDNA transcription. To test this, we applied a multiplex droplet digital PCR that identifies the dominant source of HBsAg mRNAs to 3,436 single cells from paired liver biopsies obtained from 10 people with CHB and HIV receiving NUCs. With increased NUC duration, cells producing HBsAg mRNAs shifted their transcription from chiefly cccDNA to chiefly iDNA. This shift was due to both a reduction in the number of cccDNA-containing cells and diminished cccDNA-derived transcription per cell; furthermore, it correlated with reduced detection of proteins deriving from cccDNA but not iDNA. Despite this shift in the primary source of HBsAg, rare cells remained with detectable cccDNA-derived transcription, suggesting a source for maintaining the replication cycle. Functional cure must address both iDNA and residual cccDNA transcription. Further research is required to understand the significance of HBsAg when chiefly derived from iDNA.
Authors
Maraake Taddese, Tanner Grudda, Giulia Belluccini, Mark Anderson, Gavin Cloherty, Hyon S. Hwang, Monika Mani, Che-Min Lo, Naomi Esrig, Mark S. Sulkowski, Richard K. Sterling, Yang Zhang, Ruy M. Ribeiro, David L. Thomas, Chloe L. Thio, Ashwin Balagopal
×Abstract
Protein arginine methyl transferases (PRMTs) are generally upregulated in cancers. However, the mechanisms leading to this upregulation and its biological consequences are poorly understood. Here, we identify PRMT5, the main symmetric arginine methyltransferase, as a critical driver of chemoresistance in high-grade serous ovarian cancer (HGSOC). PRMT5 levels and its enzymatic activity are induced in a platinum-resistant (Pt-resistant) state at the protein level. To reveal potential regulators of high PRMT5 protein levels, we optimized intracellular immunostaining conditions and performed unbiased CRISPR screening. We identified Kelch-like ECH-associated protein 1 (KEAP1) as a top-scoring negative regulator of PRMT5. Our mechanistic studies show that KEAP1 directly interacted with PRMT5, leading to its ubiquitin-dependent degradation under normal physiological conditions. At the genomic level, ChIP studies showed that elevated PRMT5 directly interacted with the promoters of stress response genes and positively regulated their transcription. Combined PRMT5 inhibition with Pt resulted in synergistic cellular cytotoxicity in vitro and reduced tumor growth in vivo in Pt-resistant patient-derived xenograft tumors. Overall, the findings from this study identify PRMT5 as a critical therapeutic target in Pt-resistant HGSOC cells and reveal the molecular mechanisms that lead to high PRMT5 levels in Pt-treated and chemo-resistant tumors.
Authors
Harun Ozturk, Fidan Seker-Polat, Neda Abbaszadeh, Yasemin Kingham, Sandra Orsulic, Mazhar Adli
×Abstract
BACKGROUND This study examined the underlying cellular mechanisms associated with insulin resistance (IR) and metabolic disease risk within subcutaneous adipose tissue (SAT) in youth with obesity and IR compared with those without IR.METHODS Thirteen adolescents who were insulin sensitive (IS) and 17 adolescents with IR and obesity underwent a 3-hour oral glucose tolerance test and MRI to measure abdominal fat distribution and liver fat content. Lipolysis was determined by glycerol turnover ([2H5]-glycerol infusion) and adipose triglyceride lipase (ATGL) phosphorylation (Western blot) from SAT samples biopsied prior to and 30-minutes following insulin infusion during a hyperinsulinemic-euglycemic clamp (HEC).RESULTS Glycerol turnover suppression during the HEC (first step) was lower in participants with IR compared with those with IS. Prior to insulin infusion, activated ATGL (reflected by the p-ATGL (Ser406)-to-ATGL ratio) was greater in participants with IR compared with those with IS and suppressed in response to a 30-minute insulin exposure in participants with IS, but not in those with IR. Lastly, greater ATGL inactivation is associated with greater glycerol suppression and lower liver fat.CONCLUSIONS Insulin-mediated inhibition of adipose tissue lipolysis via ATGL is dysregulated among adolescents with IR compared with those with IS, thereby serving as a vital mechanism linking glucose and insulin dysregulation and ectopic lipid storage within the liver.FUNDING This work was supported by funding from the NIH (R01-HD028016-25A1, T32- DK-007058, R01-DK124272, RO1-DK119968, R01MD015974, RO1-DK113984, P3-DK045735, RO1-DK133143, and RC2-DK120534) and the Robert E. Leet and Clara Guthrie Patterson Trust Mentored Research Award.
Authors
Aaron L. Slusher, Nicola Santoro, Alla Vash-Margita, Alfonso Galderisi, Pamela Hu, Fuyuze Tokoglu, Zhongyao Li, Elena Tarabra, Jordan Strober, Daniel F. Vatner, Gerald I. Shulman, Sonia Caprio
×Abstract
Constitutively active mutations of KRAS are prevalent in non–small cell lung cancer (NSCLC). However, the relationship between these mutations and resistance to platinum-based chemotherapy and the underlying mechanisms remain elusive. In this study, we demonstrate that KRAS mutants confer resistance to platinum in NSCLC. Mechanistically, KRAS mutants mediate platinum resistance in NSCLC cells by activating ERK/JNK signaling, which inhibits AlkB homolog 5 (ALKBH5) N6-methyladenosine (m6A) demethylase activity by regulating posttranslational modifications (PTMs) of ALKBH5. Consequently, the KRAS mutant leads to a global increase in m6A methylation of mRNAs, particularly damage-specific DNA-binding protein 2 (DDB2) and XPC, which are essential for nucleotide excision repair. This methylation stabilized the mRNA of these 2 genes, thus enhancing NSCLC cells’ capability to repair platinum-induced DNA damage and avoid apoptosis, thereby contributing to drug resistance. Furthermore, blocking KRAS-mutant–induced m6A methylation, either by overexpressing a SUMOylation-deficient mutant of ALKBH5 or by inhibiting methyltransferase-like 3 (METTL3) pharmacologically, significantly sensitizes KRAS-mutant NSCLC cells to platinum drugs in vitro and in vivo. Collectively, our study uncovers a mechanism that mediates KRAS-mutant–induced chemoresistance in NSCLC cells by activating DNA repair through the modulation of the ERK/JNK/ALKBH5 PTM-induced m6A modification in DNA damage repair–related genes.
Authors
Fang Yu, Shikan Zheng, Chunjie Yu, Sanhui Gao, Zuqi Shen, Rukiye Nar, Zhexin Liu, Shuang Huang, Lizi Wu, Tongjun Gu, Zhijian Qian
×Abstract
Rheumatoid arthritis (RA) is a systemic autoimmune disease currently with no universally highly effective prevention strategies. Identifying pathogenic immune phenotypes in at-risk populations prior to clinical onset is crucial to establishing effective prevention strategies. Here, we applied multimodal single-cell technologies (mass cytometry and CITE-Seq) to characterize the immunophenotypes in blood from at-risk individuals (ARIs) identified through the presence of serum antibodies against citrullinated protein antigens (ACPAs) and/or first-degree relative (FDR) status, as compared with patients with established RA and people in a healthy control group. We identified significant cell expansions in ARIs compared with controls, including CCR2+CD4+ T cells, T peripheral helper (Tph) cells, type 1 T helper cells, and CXCR5+CD8+ T cells. We also found that CD15+ classical monocytes were specifically expanded in ACPA-negative FDRs, and an activated PAX5lo naive B cell population was expanded in ACPA-positive FDRs. Further, we uncovered the molecular phenotype of the CCR2+CD4+ T cells, expressing high levels of Th17- and Th22-related signature transcripts including CCR6, IL23R, KLRB1, CD96, and IL22. Our integrated study provides a promising approach to identify targets to improve prevention strategy development for RA.
Authors
Jun Inamo, Joshua Keegan, Alec Griffith, Tusharkanti Ghosh, Alice Horisberger, Kaitlyn Howard, John F. Pulford, Ekaterina Murzin, Brandon Hancock, Salina T. Dominguez, Miranda G. Gurra, Siddarth Gurajala, Anna Helena Jonsson, Jennifer A. Seifert, Marie L. Feser, Jill M. Norris, Ye Cao, William Apruzzese, S. Louis Bridges, Vivian P. Bykerk, Susan Goodman, Laura T. Donlin, Gary S. Firestein, Joan M. Bathon, Laura B. Hughes, Andrew Filer, Costantino Pitzalis, Jennifer H. Anolik, Larry Moreland, Nir Hacohen, Joel M. Guthridge, Judith A. James, Carla M. Cuda, Harris Perlman, Michael B. Brenner, Soumya Raychaudhuri, Jeffrey A. Sparks, The Accelerating Medicines Partnership RA/SLE Network, V. Michael Holers, Kevin D. Deane, James Lederer, Deepak A. Rao, Fan Zhang
×Abstract
Despite advances in the development of direct KRAS inhibitors, KRAS-mutant cancers continue to exhibit resistance to the currently available therapies. Here, we identified REGγ as a mutant KRAS–associated factor that enhanced REGγ transcription through the KRAS intermediate NRF2, suggesting that the REGγ-proteasome is a potential target for pan-KRAS inhibitor development. We elucidated a mechanism involving the KRAS/NRF2/REGγ regulatory axis, which links activated KRAS to the ATP- and ubiquitin-independent proteasome. We subsequently developed RLY01, a REGγ-proteasome inhibitor that effectively suppressed tumor growth in KRAS-mutant cancer models and lung cancer organoids. Notably, the combination of RLY01 and the KRASG12C inhibitor AMG510 exhibited enhanced antitumor efficacy in KRASG12C cancer cells. Collectively, our data support the hypothesis that KRAS mutations enhance the capacity of the REGγ-proteasome by increasing REGγ expression, highlighting the potential of ubiquitin-independent proteasome inhibition as a therapeutic approach for pan-KRAS–mutant cancers.
Authors
Shihui Shen, Qiansen Zhang, Yuhan Wang, Hui Chen, Shuangming Gong, Yun Liu, Conghao Gai, Hansen Chen, Enhao Zhu, Bo Yang, Lin Liu, Siyuan Cao, Mengting Zhao, Wenjie Ren, Mengjuan Li, Zhuoya Peng, Lu Zhang, Shaoying Zhang, Juwen Shen, Bianhong Zhang, Patrick K.H. Lee, Kun Li, Lei Li, Huaiyu Yang
×Abstract
Adipose tissue lipolysis is the process by which triglycerides in lipid stores are hydrolyzed into free fatty acids (FFAs), serving as fuel during fasting or cold-induced thermogenesis. Although cytosolic lipases are considered the predominant mechanism of liberating FFAs, lipolysis also occurs in lysosomes via lysosomal acid lipase (LIPA), albeit with unclear roles in lipid storage and whole-body metabolism. We found that adipocyte LIPA expression increased in adipose tissue of mice when lipolysis was stimulated during fasting, cold exposure, or β-adrenergic agonism. This was functionally important, as inhibition of LIPA genetically or pharmacologically resulted in lower plasma FFAs under lipolytic conditions. Furthermore, adipocyte LIPA deficiency impaired thermogenesis and oxygen consumption and rendered mice susceptible to diet-induced obesity. Importantly, lysosomal lipolysis was independent of adipose triglyceride lipase, the rate-limiting enzyme of cytosolic lipolysis. Our data suggest a significant role for LIPA and lysosomal lipolysis in adipocyte lipid metabolism beyond classical cytosolic lipolysis.
Authors
Yu-Sheng Yeh, Trent D. Evans, Mari Iwase, Se-Jin Jeong, Xiangyu Zhang, Ziyang Liu, Arick Park, Ali Ghasemian, Borna Dianati, Ali Javaheri, Dagmar Kratky, Satoko Kawarasaki, Tsuyoshi Goto, Hanrui Zhang, Partha Dutta, Francisco J. Schopfer, Adam C. Straub, Jaehyung Cho, Irfan J. Lodhi, Babak Razani
×Abstract
Mycobacterium tuberculosis causes human tuberculosis (TB). As mycobacteria are protected by a thick lipid cell wall, humans have developed immune responses against diverse mycobacterial lipids. Most of these immunostimulatory lipids are known as adjuvants acting through innate immune receptors, such as C-type lectin receptors. Although a few mycobacterial lipid antigens activate unconventional T cells, the antigenicity of most adjuvantic lipids is unknown. Here, we identified that trehalose monomycolate (TMM), an abundant mycobacterial adjuvant, activated human T cells bearing a unique αβ T cell receptor (αβTCR). This recognition was restricted by CD1b, a monomorphic antigen-presenting molecule conserved in primates but not mice. Single-cell TCR-RNA-Seq using newly established CD1b-TMM tetramers revealed that TMM-specific T cells were present as CD4+ effector memory T cells in the periphery of uninfected donors but expressed IFN-γ, TNF, and anti-mycobacterial effectors upon TMM stimulation. TMM-specific T cells were detected in cord blood and PBMCs of donors without bacillus Calmette-Guérin vaccination but were expanded in patients with active TB. A cryo-electron microscopy study of CD1b-TMM-TCR complexes revealed unique antigen recognition by conserved features of TCRs, positively charged CDR3α, and long CDR3β regions. These results indicate that humans have a commonly shared and preformed CD4+ T cell subset recognizing a typical mycobacterial adjuvant as an antigen. Furthermore, the dual role of TMM justifies reconsideration of the mechanism of action of adjuvants.
Authors
Yuki Sakai, Minori Asa, Mika Hirose, Wakana Kusuhara, Nagatoshi Fujiwara, Hiroto Tamashima, Takahiro Ikazaki, Shiori Oka, Kota Kuraba, Kentaro Tanaka, Takashi Yoshiyama, Masamichi Nagae, Yoshihiko Hoshino, Daisuke Motooka, Ildiko Van Rhijn, Xiuyuan Lu, Eri Ishikawa, D. Branch Moody, Takayuki Kato, Shinsuke Inuki, Go Hirai, Sho Yamasaki
×Abstract
BACKGROUND B7H3, also known as CD276, is notably overexpressed in various malignant tumor cells in humans, with extremely high expression rates. The development of a radiotracer that targets B7H3 may provide a universal tumor-specific imaging agent and allow the noninvasive assessment of the whole-body distribution of B7H3-expressing lesions.METHODS We enhanced and optimized the structure of an affibody (ABY) that targets B7H3 to create the radiolabeled radiotracer [68Ga]Ga-B7H3-BCH, and then, we conducted both foundational experiments and clinical translational studies.RESULTS [68Ga]Ga-B7H3-BCH exhibited high affinity (equilibrium dissociation constant [KD] = 4.5 nM), and it was taken up in large amounts by B7H3-transfected cells (A549CD276 and H1975CD276 cells); these phenomena were inhibited by unlabeled precursors. Moreover, PET imaging of multiple xenograft models revealed extensive [68Ga]Ga-B7H3-BCH uptake by tumors. In a clinical study including 20 patients with malignant tumors, the [68Ga]Ga-B7H3-BCH signal aggregated in both primary and metastatic lesions, surpassing fluorine-18 fluorodeoxyglucose (18F-FDG) in overall diagnostic efficacy for tumors (85.0% vs. 81.7%), including differentiated hepatocellular and metastatic gastric cancers. A strong correlation between B7H3 expression and [68Ga]Ga-B7H3-BCH uptake in tumors was observed, and B7H3 expression was detected with 84.38% sensitivity and 100% specificity when a maximum standardized uptake value (SUVmax) of 3.85 was set as the cutoff value. Additionally, B7H3-specific PET imaging is expected to predict B7H3 expression levels in tumor cells, intratumoral stroma, and peritumoral tissues.CONCLUSION In summary, [68Ga]Ga-B7H3-BCH has potential for the noninvasive identification of B7H3 expression in systemic lesions in patients with malignant tumors. This agent has prospects for improving pretreatment evaluation, predicting therapeutic responses, and monitoring resistance to therapy in patients with malignancies.TRIAL REGISTRATION ClinicalTrials.gov NCT06454955.FUNDING This research was financially supported by the Natural Science Foundation of Beijing Municipality (no. 7242266), the National Natural Science Foundation of China (no. 82202201), and the Young Elite Scientists Sponsorship Program by China Association for Science and Technology (CAST) (no. YESS20220230).
Authors
Lei Xia, Yan Wu, Yanan Ren, Zhen Wang, Nina Zhou, Wenyuan Zhou, Lixin Zhou, Ling Jia, Chengxue He, Xiangxi Meng, Hua Zhu, Zhi Yang
×Abstract
BACKGROUND Mucus plugs form in acute asthma and persist in chronic disease. Although eosinophils are implicated in mechanisms of mucus pathology, many mechanistic details about mucus plug formation and persistence in asthma are unknown.METHODS Using histology and spatial, single-cell proteomics, we characterized mucus-plugged airways from nontransplantable donor lungs of 14 patients with asthma (9 with fatal asthma and 5 with nonfatal asthma) and individuals acting as controls (10 with chronic obstructive pulmonary disease and 14 free of lung disease). Additionally, we used an airway epithelial cell–eosinophil (AEC-eosinophil) coculture model to explore how AEC mucus affects eosinophil degranulation.RESULTS Asthma mucus plugs were tethered to airways showing infiltration with innate lymphoid type 2 cells and hyperplasia of smooth muscle cells and MUC5AC-expressing goblet cells. Asthma mucus plugs were infiltrated with immune cells that were mostly dual positive for eosinophil peroxidase (EPX) and neutrophil elastase, suggesting that neutrophils internalize EPX from degranulating eosinophils. Indeed, eosinophils exposed to mucus from IL-13–activated AECs underwent CD11b- and glycan-dependent cytolytic degranulation. Dual-positive granulocytes varied in frequency in mucus plugs. Whereas paucigranulocytic plugs were MUC5AC rich, granulocytic plugs had a mix of MUC5AC, MUC5B, and extracellular DNA traps. Paucigranulocytic plugs occurred more frequently in (acute) fatal asthma and granulocytic plugs predominated in (chronic) nonfatal asthma.CONCLUSION Together, our data suggest that mucin-rich mucus plugs in fatal asthma form because of acute goblet cell degranulation in remodeled airways and that granulocytic mucus plugs in chronic asthma persist because of a sustaining niche characterized by epithelial cell–mucin-granulocyte cross-talk.FUNDING NIH grants HL080414, HL107202, and AI077439.
Authors
Maude A. Liegeois, Aileen Hsieh, May Al-Fouadi, Annabelle R. Charbit, Chen Xi Yang, Tillie-Louise Hackett, John V. Fahy
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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)