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Abstract
Complement activation is a relevant driver in the pathomechanisms of vasculitis. The involved proteins in the interaction between endothelia, complement and platelets in these conditions are only partially understood. Thrombospondin-1 (TSP-1), found in platelet α-granules and released from activated endothelial cells, interacts with factor H (FH) and von Willebrand factor (vWF). However, direct regulatory interaction with the complement cascade has not yet been described. We could show that TSP-1 is a potent, FH-independent inhibitor of the alternative complement pathway. TSP-1 binds to complement proteins, inhibits cleavage of C3 and C5 and the formation of the membrane attack complex. Complement-regulatory function is validated in blood samples from patients with primary complement defects. Physiological relevance of TSP-1 is demonstrated in ANCA-associated vasculitis (AAV) patients by significantly enhanced TSP-1 staining in glomerular lesions and increased complement activity and NETosis following TSP-1 deficiency in an in vitro and in vivo model of AAV. The newly described complement-inhibiting function of TSP-1 represents an important mechanism in the interaction of endothelia and complement. In particular, the interplay between released TSP-1 and the complement system locally, especially on surfaces, influences the balance between complement activation and inhibition and may be relevant in various vascular diseases.
Authors
Swagata Konwar, Sophie Schroda, Manuel Rogg, Jessika Kleindienst, Eva L. Decker, Martin Pohl, Barbara Zieger, Jens Peter Panse, Hong Wang, Robert Grosse, Christoph Schell, Sabine Vidal, Xiaobo Liu, Christian Gorzelanny, Todor Tschongov, Karsten Häffner
Abstract
We leveraged specimens from the RV217 prospective study that enrolled participants at high risk of HIV-1 acquisition to investigate how NK, conventional T cells, and unconventional T cells influence HIV-1 acquisition. We observed low levels of α4β7 expression on memory CD4 T cells and iNKT cells, two cell types highly susceptible to HIV-1 infection, in highly exposed seronegative (HESN) compared to highly exposed seroconverter (HESC) participants. NK cells from HESN had higher levels of α4β7 compared to HESC, presented a quiescent phenotype, and had a higher capacity to respond to opsonized target cells. We also measured translocated microbial products in plasma and found differences in phylum distribution between HESN and HESC that were associated with the immune phenotypes impacting the risk of HIV-1 acquisition. Finally, a logistic regression model combining features of NK cells activation, α4β7 expression on memory CD4 T cells, and Tbet expression by iNKT cells achieved the highest accuracy in identifying HESN and HESC participants. This immune signature comprised of increased α4β7 on cells susceptible to HIV infection combined with higher NK cells activation and lower gut homing potential could impact the efficacy of HIV-1 prevention strategies such as vaccines.
Authors
Kawthar Machmach, Kombo F. N'guessan, Rohit Farmer, Sucheta Godbole, Dohoon Kim, Lauren McCormick, Noemia S. Lima, Amy R. Henry, Farida Laboune, Isabella Swafford, Sydney K. Mika, Bonnie M. Slike, Jeffrey R. Currier, Leigh Anne Eller, Julie A. Ake, Sandhya Vasan, Merlin L. Robb, Shelly J. Krebs, Daniel C. Douek, Dominic Paquin-Proulx
Abstract
The activated JAK2/STAT pathway is characteristic of myeloproliferative neoplasms (MPNs). Pleckstrin-2 (PLEK2) signalosome is downstream of the JAK2/STAT5 pathway and plays an important role in MPN development. The detailed molecular composition of this signalosome is unclear. Here, we revealed peptidylprolyl isomerase-like 2 (PPIL2) as a critical component of the complex in regulating human and murine erythropoiesis. PPIL2 was a direct target of STAT5 and was upregulated in MPN patients and a Jak2V617F MPN mouse model. Mechanistically, PPIL2 interacted with and catalyzed p53 polyubiquitination and proteasome-mediated degradation to promote cell growth. Ppil2 deficiency, or inhibition by cyclosporin A, led to a marked upregulation of p53 in vivo and ameliorated myeloproliferative phenotypes in Jak2V617F mice. Cyclosporin A also markedly reduced JAK2 mutated erythroid and myeloid proliferation in an induced pluripotent stem cell-derived human bone marrow organoid model. Our findings revealed PPIL2 as a critical component of the PLEK2 signalosome in driving MPN pathogenesis through negatively regulating p53, thus providing a target and an opportunity for drug repurposing by using cyclosporin A to treat MPNs.
Authors
Pan Wang, Xu Han, Kehan Ren, Ermin Li, Honghao Bi, Inci Aydemir, Madina Sukhanova, Yijie Liu, Jing Yang, Peng Ji
Abstract
Phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, is a common cause of intellectual disability. However, the mechanisms by which elevated phenylalanine (Phe) levels cause cognitive impairment remain unclear. Here, we show that submillimolar Phe perturbs synaptic plasticity through the hyperactivation of GluN2B-containing NMDARs. PahEnu2 PKU model mice exhibited submillimolar and supramillimolar concentrations of Phe in the cerebrospinal fluid (CSF) and serum, respectively. L-Phe produced concentration-dependent bidirectional effects on NMDA-induced currents, without affecting synaptic NMDARs in hippocampal CA1 neurons. L-Phe-induced hyperactivation of extrasynaptic GluN2B resulted in activity-dependent downregulation of AMPARs during burst or sustained synaptic activity. Administration of L-Phe in mice decreased neural activity and impaired memory, which were blocked by pretreatment with GluN2B inhibitors. Furthermore, pharmacological and virus-mediated suppression of GluN2B reversed the impaired learning in PahEnu2 mice. Collectively, these results suggest that the concentration of Phe in the CSF of patients with PKU perturbs extrasynaptic NMDARs and synaptic plasticity, and that suppression of GluN2B may have the potential to improve cognitive function in patients with PKU.
Authors
Woo Seok Song, Young Sook Kim, Young-Soo Bae, Sang Ho Yoon, Jae Min Lim, Myoung-Hwan Kim
Abstract
Background: Tebentafusp is the first T-cell receptor-based bispecific protein approved for clinical use in HLA-A*02:01+ adult patients with unresectable/metastatic uveal melanoma. It redirects T-cells toward gp100-expressing target cells, frequently inducing skin-related early adverse events. Methods: This study investigated immunological and cellular responses using single-cell and spatial analysis of skin biopsies from patients with metastatic uveal melanoma treated with tebentafusp. Results: 81.8% of patients developed acute cutaneous adverse events, which correlated with improved survival. Multimodal analysis revealed a brisk infiltration of CD4+ and CD8+ T-cells, while melanocyte numbers declined. Single-cell RNA-sequencing revealed T-cell activation, proliferation, and IFN-γ/cytotoxic gene upregulation. CD8+ T-cells co-localized with melanocytes and upregulated LAG3, suggesting potential for combination therapies with tebentafusp. Melanocytes upregulated antigen presentation and apoptotic pathways, while pigmentation gene expression decreased. However, gp100 remained stably expressed. Conclusion: Sequential skin biopsies enable in vivo pharmacodynamic modeling of tebentafusp, offering insights into immune activation, toxicity, and treatment response. Examining the on-target effects of bispecifics in tissues amenable to longitudinal sampling enhances our understanding of toxicity and therapeutic escape mechanisms, guiding strategies for treatment optimization.
Authors
Ramon Staeger, Aizhan Tastanova, Adhideb Ghosh, Nicola Winkelbeiner, Prachi Shukla, Isabel Kolm, Patrick Turko, Adel Benlahrech, Jane Harper, Anna Broomfield, Antonio Camera, Marianna Ambrosio, Veronika Haunerdinger, Phil F. Cheng, Egle Ramelyte, James P. Pham, Stefanie Kreutmair, Burkhard Becher, Mitchell P. Levesque, Reinhard Dummer, Barbara Meier-Schiesser
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI190824.
Abstract
The rapid viral rebound observed following treatment interruption, despite prolonged time on antiretroviral therapy with plasma HIV-RNA levels <40 copies/mL, suggests persistent HIV-1 reservoir(s) outside of the blood. Studies of HIV-1 proviruses in autopsy tissue samples have hinted at their persistence. However, their distribution across different anatomical compartments and their transcriptional activity within tissues remains unclear. The present study has examined molecular DNA and RNA reservoirs of HIV-1 in autopsy samples from 13 individuals with HIV-1 infection. Of the 13, 5 had detectable levels of HIV-1 RNA in plasma while 8 did not. Cell associated HIV-RNA was detected in 12 out of 13 donors and in 27 of the 30 different tissues examined. HIV-specific DNA and RNA were widely distributed and predominantly associated with clonal expansions. No significant differences were noted between the groups and no tissues were preferentially affected. These data imply that a substantial seeding of tissues with cells harboring transcriptionally active proviral DNA can be seen in the setting of HIV-1 infection despite ART and highlight one of the challenges in achieving an HIV-1 cure.
Authors
Hiromi Imamichi, Ven Natarajan, Francesca Scrimieri, Mindy Smith, Yunden Badralmaa, Marjorie Bosche, Jack M. Hensien, Thomas Buerkert, Weizhong Chang, Brad T. Sherman, Kanal Singh, H. Clifford Lane
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI187862.
Abstract
Stem-like T cells selectively contribute to autoimmunity, but the activities that promote their pathogenicity are incompletely understood. Here, we identify the transcription coregulator OCA-B as a driver of the pathogenic maturation of stem-like CD4+ T cell to promote autoimmune demyelination. Using two human multiple sclerosis (MS) datasets, we show that POU2AF1, the gene encoding OCA-B, is elevated in CD4+ T cells from MS patients. We show that T cell-intrinsic OCA-B loss protects mice from experimental autoimmune encephalomyelitis (EAE) while preserving responses to viral CNS infection. In EAE models driven by antigen reencounter, OCA-B deletion nearly eliminates CNS infiltration, proinflammatory cytokine production and clinical disease. OCA-B-expressing CD4+ T cells of mice primed with autoantigen express an encephalitogenic gene program and preferentially confer disease. In a relapsing-remitting EAE model, OCA-B loss protects mice specifically at relapse. During remission, OCA-B promotes the expression of Tcf7, Slamf6, and Sell in proliferating CNS T cell populations. At relapse timepoints, OCA-B loss results in both the accumulation of an immunomodulatory CD4+ T cell population expressing Ccr9 and Bach2, and loss of pro-inflammatory gene expression from Th17 cells. These results identify OCA-B as a driver of pathogenic CD4+ T cells.
Authors
Erik P. Hughes, Amber R. Syage, Elnaz Mirzaei Mehrabad, Thomas E. Lane, Benjamin T. Spike, Dean Tantin
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI190855.
Abstract
Synovial sarcoma is an aggressive soft tissue cancer driven by the chimeric SS18::SSX fusion oncoprotein, which disrupts chromatin remodeling by combining two antagonistic transcriptional regulators. SS18 participates in BAF complexes that open chromatin, while the SSX genes are cancer-testis antigens that interface with chromatin decorated with monoubiquitinated histone H2A placed by Polycomb repressive complexes (PRCs) activity. Because KDM2B brings PRC to unmethylated CpG islands, it is plausible that methylation directly determines the distribution of SS18::SSX to target loci. Given that synovial sarcoma is also characterized by a peculiarly low DNA hypomethylation profile, we hypothesized that further disturbance of DNA methylation would have a negative impact on synovial sarcoma growth. DNMT1 disruption by CRISPR/Cas9 targeting or pharmacologic inhibition with cytidine analogs 5-aza-2ʹ-deoxycytidine (decitabine) and 5-azacytidine led to decreased genome-wide methylation, redistribution of SS18::SSX, and altered gene expression profiles, most prominently including upregulation of tumor suppressor genes, immune-related genes, and mesenchymal differentiation-related genes. These drugs suppressed growth of synovial sarcoma cell lines and drove cytoreduction in mouse genetic models. DNMT1 inhibitors, already approved for treating myelodysplastic syndromes, warrant further clinical investigation for synovial sarcoma as repurposed, targeted treatments exploiting a vulnerability in the intrinsic biology of this cancer.
Authors
Nobuhiko Hasegawa, Nezha S. Benabdallah, Kyllie Smith-Fry, Li Li, Sarah McCollum, Jinxiu Li, Caelen A. Jones, Lena Wagner, Vineet Dalal, Viola Golde, Anastasija Pejkovska, Lara Carroll, Malay Haldar, Seth M. Pollack, Scott W. Lowe, Torsten O. Nielsen, Ana Banito, Kevin B. Jones
Abstract
The ATP6V0A4 gene encodes the a4 subunit of Vacuolar H+-ATPase (V-ATPase), which mediates hydrogen ion transport across the membrane. Previous studies have suggested that mutations in ATP6V0A4 consistently result in a loss of function (LOF), impairing the hydrogen ion transport efficacy of V-ATPase and leading to distal renal tubular acidosis (dRTA) and sensorineural hearing loss. Here, we identified a 32-year-old male patient and his father, both of whom harbored a heterozygous ATP6V0A4 p.V512L mutation, and both exhibited with hypochloremic metabolic alkalosis, acidic urine and hypokalemia. Through a series of protein structural analyses and functional experiments, the V512L mutation was confirmed as a gain-of-function (GOF) mutation in the ATP6V0A4 gene. V512-a4 increased a4 subunit expression abundance by enhancing V512L-a4 stability and reducing its degradation, which in turn potentiated V-ATPase's capacity to acidify the tubular lumen, leading to acidic urine and metabolic alkalosis. Through mutant V512L-a4 subunit structure-based virtual and experimental screening, we discovered F351 (C25H26FN3O2S), a small-molecule inhibitor specifically targeting the V512L-a4 mutant. In conclusion, we identify a GOF mutation in the ATP6V0A4 gene, broadening its phenotypic and mutational spectrum, and provide valuable insights into potential therapeutic approaches for diseases associated with ATP6V0A4 mutations.
Authors
Si-qi Peng, Qian-qian Wu, Wan-yi Wang, Yi-Lin Zhang, Rui-ning Zhou, Jun Liao, Jin-xuan Wei, Yan Yang, Wen Shi, Jun-lan Yang, Xiao-xu Wang, Zhi-yuan Wei, Jia-xuan Sun, Lu Huang, Hong Fan, Hui Cai, Cheng-kun Wang, Xin-hua Li, Ting-song Li, Bi-Cheng Liu, Xiao-liang Zhang, Bin Wang
Abstract
Hormone receptor-positive and human epidermal growth factor receptor 2-negative breast cancer (HR+/HER2− BC) is the most common subtype, with high risk of long-term recurrence and metastasis. Endocrine therapy (ET) combined with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors is a standard treatment for advanced/metastatic HR+/HER2- BC, but resistance remains a major clinical challenge. We report that kinesin family member C2 (KIFC2) was amplified in approximately 50% HR+/HER2- BC, and its high expression was associated with poor disease outcome, increased tumor protein p53 (TP53) somatic mutation, and active pyrimidine metabolism. Function assays revealed that depletion of KIFC2 suppressed growth and enhanced sensitivity of HR+/HER2- BC cells to tamoxifen and CDK4/6 inhibitors. Mechanistically, KIFC2 stabilized CDK4 by enhancing its interaction with ubiquitin specific peptidase 9 X-linked (USP9X). Importantly, re-expression of CDK4 in KIFC2-depleted cells partially rescued the decreased growth and increased sensitivity to tamoxifen and CDK4/6 inhibitors caused by KIFC2 depletion. Clinically, high KIFC2 mRNA expression was negatively associated with survival rate of HR+/HER2- BC patients received adjuvant ET alone or in combination with CDK4/6 inhibitors. Collectively, these findings identify an important role for KIFC2 in HR+/HER2- BC growth and therapeutic resistance, and support its potential as a therapeutic target and predictive biomarker.
Authors
Shao-Ying Yang, Ming-Liang Jin, Lisa Andriani, Qian Zhao, Yun-Xiao Ling, Cai-Jin Lin, Min-Ying Huang, Jia-Yang Cai, Yin-Ling Zhang, Xin Hu, Zhi-Ming Shao, Fang-Lin Zhang, Xi Jin, A Yong Cao, Da-Qiang Li
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI191021.
Abstract
The progression of metabolic dysfunction-associated steatotic liver disease (MASLD) to metabolic dysfunction-associated steatohepatitis (MASH) involves alterations in both liver-autonomous and systemic metabolism that influence the liver’s balance of fat accretion and disposal. Here, we quantify the contributions of hepatic oxidative pathways to liver injury in MASLD-MASH. Using NMR spectroscopy, UHPLC-MS, and GC-MS, we performed stable-isotope tracing and formal flux modeling to quantify hepatic oxidative fluxes in humans across the spectrum of MASLD-MASH, and in mouse models of impaired ketogenesis. In humans with MASH, liver injury correlated positively with ketogenesis and total fat oxidation, but not with turnover of the tricarboxylic acid cycle. Loss-of-function mouse models demonstrated that disruption of mitochondrial HMG-CoA synthase (HMGCS2), the rate-limiting step of ketogenesis, impairs overall hepatic fat oxidation and induces a MASLD-MASH-like phenotype. Disruption of mitochondrial β-hydroxybutyrate dehydrogenase (BDH1), the terminal step of ketogenesis, also impaired fat oxidation, but surprisingly did not exacerbate steatotic liver injury. Taken together, these findings suggest that quantifiable variations in overall hepatic fat oxidation may not be a primary determinant of MASLD-to-MASH progression, but rather, that maintenance of ketogenesis could serve a protective role through additional mechanisms that extend beyond overall rates of fat oxidation.
Authors
Eric D. Queathem, David B. Stagg, Alisa B. Nelson, Alec B. Chaves, Scott B. Crown, Kyle Fulghum, D. Andre d'Avignon, Justin R. Ryder, Patrick J. Bolan, Abdirahman Hayir, Jacob R. Gillingham, Shannon Jannatpour, Ferrol I. Rome, Ashley S. Williams, Deborah M. Muoio, Sayeed Ikramuddin, Curtis C. Hughey, Patrycja Puchalska, Peter A. Crawford
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI168412.
Abstract
Patients with systemic lupus erythematosus (SLE) are photosensitive, developing skin inflammation with even ambient ultraviolet radiation (UVR), and this cutaneous photosensitivity can be associated with UVR-induced flares of systemic disease, which can involve increased autoantibodies and further end organ injury. Mechanistic insight into the link between the skin responses and autoimmunity is limited. Signals from skin are transmitted directly to the immune system via lymphatic vessels, and here we show evidence for potentiation of UVR-induced lymphatic flow dysfunction in SLE patients and murine models. Improving lymphatic flow by manual lymphatic drainage (MLD) or with a transgenic model with increased lymphatic vessels reduces both cutaneous inflammation and lymph node B and T cell responses, and long term MLD reduces splenomegaly and titers of a number of autoantibodies. Mechanistically, improved flow restrains B cell responses in part by stimulating a lymph node fibroblastic reticular cell-monocyte axis. Our results point to lymphatic modulation of lymph node stromal function as a link between photosensitive skin responses and autoimmunity and as a therapeutic target in lupus, provide insight into mechanisms by which the skin state regulates draining lymph node function, and suggest the possibility of MLD as an accessible and cost-effective adjunct to add to ongoing medical therapies for lupus and related diseases.
Authors
Mir J. Howlader, William G. Ambler, Madhavi Latha S. Chalasani, Aahna Rathod, Ethan S. Seltzer, Ji Hyun Sim, Jinyeon Shin, Noa Schwartz, William D. Shipman III, Dragos C. Dasoveanu, Camila B. Carballo, Ecem Sevim, Salma Siddique, Yurii Chinenov, Scott A. Rodeo, Doruk Erkan, Raghu P. Kataru, Babak J. Mehrara, Theresa T. Lu
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI185430.
Abstract
As antimicrobial resistance rises, new antibacterial candidates are urgently needed. Using sequence space information from over 14,743 functional antimicrobial peptides (AMPs), we improved the antimicrobial properties of citropin 1.1, an AMP with weak anti-methicillin resistant Staphylococcus aureus (MRSA) activity, producing a short and potent anti-staphylococcal peptide, CIT-8 (13 residues). At 40 μg/ml, CIT-8 eradicated 1 × 108 drug-resistant MRSA and VRSA (vancomycin resistant S. aureus) persister cells within 30 mins of exposure and reduced the number of viable biofilm cells of MRSA and VRSA by 3 log10 and 4 log10 in established biofilms, respectively. CIT-8 (at 32 μg/ml) depolarized and permeated the S. aureus MW2 membrane. In a mouse model of MRSA skin infection, CIT-8 (2% w/w in petroleum jelly) significantly reduced the bacterial burden by 2.3 log10 (p < 0.0001). Our methodology accelerates AMP design by combining traditional peptide design strategies, such as truncation, substitution, and structure-guided alteration, with machine learning (ML)-backed sequence optimization.
Authors
Biswajit Mishra, Anindya Basu, Fadi Shehadeh, LewisOscar Felix, Sai Sundeep Kollala, Yashpal Singh Chhonker, Mandar T. Naik, Charilaos Dellis, Liyang Zhang, Narchonai Ganesan, Daryl J. Murry, Jianhua Gu, Michael B. Sherman, Frederick M. Ausubel, Paul P. Sotiriadis, Eleftherios Mylonakis
Abstract
BACKGROUND. Adipose tissue-derived endotrophin, a peptide cleaved from the α3 chain of collagen VI during fibrogenesis, causes systemic insulin resistance in rodent models. Here, we evaluated the potential importance of endotrophin in regulating whole-body insulin sensitivity in people. METHODS. We evaluated: i) plasma endotrophin concentration, insulin sensitivity (assessed by using the hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled glucose tracer infusion) and adipose tissue expression of genes involved in endotrophin production in three groups of participants that were rigorously stratified by adiposity and insulin sensitivity [lean insulin-sensitive (Lean-IS; n=10), obese insulin-sensitive (Obese-IS; n=10), and obesity insulin-resistant (Obese-IR; n=10)]; ii) plasma endotrophin concentration and insulin sensitivity in 15 people with obesity and type 2 diabetes before and after marked (~18%) weight loss; and iii) the effect of endotrophin on insulin signaling (AKTser473 phosporylation) and insulin action (insulin-stimulated glucose uptake) in primary human skeletal muscle myotubes. RESULTS. Plasma endotrophin progressively increased from the Lean-IS to the Obese-IS to the Obese-IR group, was negatively associated with insulin sensitivity and positively associated with factors involved in adipose tissue endotrophin production, namely adipose tissue gene expression of matrix metalloproteinases and markers of hypoxia, inflammation, and fibrosis. Marked weight loss increased insulin sensitivity in conjunction with a decrease in plasma endotrophin concentration. Endotrophin inhibited insulin insulin-stimulated AKTser473 phosphorylation and insulin-stimulated glucose uptake in myotubes, which was restored by incubation with a neutralizing endotrophin antibody. CONCLUSIONS. These results suggest plasma endotrophin is both a biomarker and cause of whole-body insulin resistance in people with obesity.
Authors
Gordon I. Smith, Samuel Klein
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI170690.
Abstract
Colistin (COL) is a cationic cyclic peptide that disrupts negatively-charged Gram-negative bacterial cell membranes and frequently serves as an antibiotic of last resort to combat multidrug-resistant Gram-negative bacterial infections. Emergence of the horizontally transferable plasmid-borne mobilized colistin resistance (mcr) determinant and its spread to Gram-negative strains harboring extended-spectrum β-lactamase and carbapenemase resistance genes threatens futility of our chemotherapeutic arsenal. COL is widely regarded to have zero activity against mcr+ strains based on standard antimicrobial susceptibility testing (AST) performed in enriched bacteriological growth media; consequently, the drug is withheld from patients with mcr+ infections. However, these standard testing media poorly mimic in vivo physiology and omit host immune factors. Here we observed that COL exhibits bactericidal activities against mcr+ isolates of Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica in tissue culture media containing the physiological buffer bicarbonate. Moreover, COL promoted serum complement deposition on the mcr-1+ Gram-negative bacterial surface and synergized potently with active human serum in pathogen killing. At COL concentrations readily achievable with standard dosing, the peptide antibiotic killed mcr-1+ E. coli, K. pneumoniae, and S. enterica in freshly isolated human blood and proved effective as monotherapy in a murine model of E. coli bacteremia. Our results suggest that COL, currently ignored as a treatment option based on traditional AST, may in fact benefit patients with mcr-1+ Gram negative infections based on evaluations performed in a more physiologic context. These concepts warrant careful consideration in the clinical microbiology laboratory and for future clinical investigation of their merits in high-risk patients with limited therapeutic options.
Authors
Monika Kumaraswamy, Angelica Riestra, Anabel Flores, Samira Dahesh, Fatemeh Askarian, Satoshi Uchiyama, Jonathan Monk, Sean Jung, Gunnar Bondsäter, Victoria Nilsson, Melanie Chang, Jürgen B Bulitta, Yinzhi Lang, Armin Kousha, Elisabet Bjånes, Natalie Chavarria, Ty'Tianna Clark, Hideya Seo, George Sakoulas, Victor Nizet
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI190106.
Abstract
The presence of B cells is essential for the formation of CD8 T cell memory after infection and vaccination. In this study, we investigated whether B cells influence the programming of naïve CD8 T cells prior to their involvement in an immune response. RNA sequencing indicated that B cells are necessary for sustaining the FOXO1-controlled transcriptional program, which is critical for their homeostasis. Without an appropriate B cell repertoire, mouse naïve CD8 T cells exhibit a terminal, effector-skewed phenotype, which significantly impacts their response to vaccination. A similar effector-skewed phenotype with reduced FOXO1 expression was observed in naïve CD8 T cells from human patients undergoing B cell-depleting therapies. Furthermore, we show that patients without B cells have a defect in generating long-lived CD8 T cell memory following COVID vaccination. In summary, we demonstrate that B cells promote the quiescence of naïve CD8 T cells, poising them to become memory cells upon vaccination.
Authors
Cameron Manes, Miguel Guerrero Moreno, Jennifer Cimons, Marc A. D'Antonio, Tonya M. Brunetti, Michael G. Harbell, Sean Selva, Christopher Mizenko, Tyler L. Borko, Erika L. Lasda, Jay R. Hesselberth, Elena W.Y. Hsieh, Michael R. Verneris, Amanda L. Piquet, Laurent Gapin, Ross M. Kedl, Jared Klarquist
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI185126.
Abstract
Fanconi anemia (FA) is a rare genetic disease characterized by loss-of-function variants in any of the 22 previously identified genes (FANCA-FANCW) that encode proteins participating in the repair of DNA interstrand crosslinks (ICLs). Patient phenotypes are variable, but may include developmental abnormalities, early onset pancytopenia, and predisposition to hematologic and solid tumors. Here, we describe two unrelated families with multiple pregnancy losses and offspring presenting with severe developmental and hematologic abnormalities leading to death in utero or in early life. Homozygous loss-of-function variants in FAAP100 were identified in affected children of both families. The FAAP100 protein associates with FANCB and FANCL, the E3 ubiquitin ligase responsible for the monoubiquitination of FANCD2 and FANCI, which is necessary for FA pathway function. Patient-derived cells exhibited phenotypes consistent with FA. Expression of the wild-type FAAP100 cDNA, but not the patient-derived variants, rescued the observed cellular phenotypes. This establishes FAAP100 deficiency as a cause of Fanconi anemia, with FAAP100 gaining an alias as FANCX. The extensive developmental malformations of individuals with FAAP100 loss-of-function variants are among the most severe across previously described FA phenotypes, indicating that the FA pathway is essential for human development.
Authors
Benjamin A. Harrison, Emma Mizrahi-Powell, John Pappas, Kristen Thomas, Subrahmanya Vasishta, Shripad Hebbar, Anju Shukla, Shalini S. Nayak, Tina K. Truong, Amy Woroch, Yara Kharbutli, Bruce D. Gelb, Cassie S. Mintz, Gilad D. Evrony, Agata Smogorzewska
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI179395.
Abstract
Diffuse midline gliomas (DMGs) are lethal brain tumors characterized by p53-inactivating mutations and oncohistone H3.3K27M mutations that rewire the cellular response to genotoxic stress. We used RCAS/tv-a retroviruses and Cre recombinase to inactivate p53 and induce native H3.3K27M mutations in a lineage- and spatially-directed manner. We generated primary mouse tumors that recapitulate human DMG. Disrupting ataxia-telangiectasia mutated kinase (ATM) enhanced the efficacy of radiation therapy in murine and patient-derived DMG models which increased survival. Microscopy-based in situ sequencing was used to spatially resolve transcriptional profiles in >750,000 single cells with or without ATM disruption and radiation therapy, revealing altered immune-neoplastic and endothelial cell interactions after treatment. An allelic series of primary murine DMG models with different p53 mutations confirmed that transactivation-independent p53 activity is a key mediator of radiosensitivity after ATM disruption. Our findings contribute primary DMG mouse models with deep profiling and reveal the mechanisms of treatment response to an actionable therapeutic strategy.
Authors
Avani Mangoli, Vennesa Valentine, Spencer Maingi, Sophie R. Wu, Harrison Q. Liu, Michael Aksu, Vaibhav Jain, Bronwen E. Foreman, Joshua A. Regal, Loren B. Weidenhammer, Connor E. Stewart, Maria E. Guerra Garcia, Emily Hocke, Karen Abramson, Tal Falick Michaeli, Nerissa T. Williams, Lixia Luo, Megan Romero, Katherine Deland, Samantha Gadd, Eita Uchida, Laura Attardi, Kouki Abe, Rintaro Hashizume, David M. Ashley, Oren J. Becher, David G. Kirsch, Simon G. Gregory, Zachary J. Reitman
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI181471.
Abstract
The efficacy of T cell-activating therapies against glioma is limited by an immunosuppressive tumor microenvironment and tumor-induced T cell sequestration. We investigated whether peripherally infused non-antigen specific autologous lymphocytes (ALT) could accumulate in intracranial tumors. We observed that non-specific autologous CD8+ ALT cells can indeed accumulate in this context, despite endogenous T cell sequestration in bone marrow. Rates of intratumoral accumulation were markedly increased when expanding lymphocytes with IL-7 compared to IL-2. Pre-treatment with IL-7 ALT also enhanced the efficacy of multiple tumor-specific and non-tumor-specific T cell-dependent immunotherapies against orthotopic murine and human xenograft gliomas. Mechanistically, we detected increased VLA-4 on mouse and human CD8+ T cells following IL-7 expansion, with increased transcription of genes associated with migratory integrin expression (CD9). We also observed that IL-7 increases S1PR1 transcription in human CD8+ T cells, which we have shown to be protective against tumor-induced T cell sequestration. These observations demonstrate that expansion with IL-7 enhances the capacity of ALT to accumulate within intracranial tumors, and that pre-treatment with IL-7 ALT can boost the efficacy of subsequent T cell-activating therapies against glioma. Our findings will inform the development of future clinical trials where ALT pre-treatment can be combined with T cell-activating therapies.
Authors
Kirit Singh, Kelly M. Hotchkiss, Sarah L. Cook, Pamy Noldner, Ying Zhou, Eliese M. Moelker, Chelsea O. Railton, Emily E. Blandford, Bhairavy J. Puviindran, Shannon E. Wallace, Pamela K. Norberg, Gary E. Archer, Beth H. Shaz, Katayoun Ayasoufi, John H. Sampson, Mustafa Khasraw, Peter E. Fecci
Citation Information: J Clin Invest. 2025. https://doi.org/10.1172/JCI184636.
Abstract
Bardet-Biedl Syndrome (BBS), a ciliopathy characterized by obesity, hyperphagia, and learning deficits, arises from mutations in BBS genes. More exacerbated symptoms occur with mutations in genes encoding the BBSome, a complex regulating primary cilia function. We investigated the mechanisms underlying BBS-induced obesity using a novel BBS5 knockout (BBS5-/-) mouse model. BBS5-/- mice displayed hyperphagia, learning deficits, glucose/insulin intolerance, and disrupted metabolic hormones, phenocopying human BBS. They displayed an unique immunophenotype in white adipose tissue with increased proinflammatory macrophages and dysfunctional regulatory T cells, suggesting a distinct mechanism for adiposity compared to typical obesity models. Additionally, BBS5-/- mice exhibited pancreatic islet hyperplasia but failed to normalize blood glucose, suggesting defective insulin action. Hypothalamic transcriptomics revealed dysregulated endocrine signaling pathways with functional analyses confirming defects in insulin, leptin, and cholecystokinin (CCK) signalling, while preserving glucagon-like peptide-1 receptor (GLP-1R) responsiveness. Notably, treatment with a GLP-1R agonist effectively alleviated hyperphagia, body weight gain, improved glucose tolerance, and circulating metabolic hormones in BBS5-/- mice. This study establishes BBS5-/- mice as a valuable translational model of BBS to understand the pathogenesis and develop novel treatments. Our findings highlight the therapeutic potential of GLP-1R agonists for managing BBS-associated metabolic dysregulation, warranting further investigation for clinical application.
Authors
Arashdeep Singh, Naila Haq, Mingxin Yang, Shelby Luckey, Samira Mansouri, Martha Campbell-Thompson, Lei Jin, Sofia Christou-Savina, Guillaume de Lartigue
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)