Commentary
Abstract
Monoclonal antibodies (mAbs) targeting Plasmodium falciparum epitopes aim to address gaps in malaria prevention, with potential to profoundly impact high-risk populations. In this issue of the JCI, Tran et al. performed pharmacokinetic and pharmacodynamic analyses on the mAb CIS43LS, which targets a unique conserved hinge region on the sporozoite protein CSP and previously demonstrated a high level of durable protection in controlled human malaria infections. Their findings establish a solid benchmark for mAb protection, demonstrating 80% protection from liver-stage invasion for 4–6 months. A clinical correlate of protection was estimated at antibody levels over 64 μg/mL. Successful protection could also be achieved from subcutaneous injections requiring lower doses. While efficacy of individual mAbs is more straightforward to demonstrate, exploring combination approaches targeting variable regions and diverse effector functions seems prudent to address the problem of evolving microbial pathogens. Combining both mAbs and long-acting malaria drugs may improve efficacy and reduce resistance.
Authors
David J. Sullivan
Abstract
The ability of cancer cells to transition between epithelial and mesenchymal states, a process known as epithelial-to-mesenchymal transition (EMT), is a key driver of cancer metastasis and therapy resistance. While ataxia telangiectasia and Rad3-related (ATR) kinase was originally characterized as a responder to DNA damage and replication stress, recent discoveries implicate a critical role for ATR in EMT and metastasis. Two pivotal studies published in this issue of JCI provide key insights into how ATR intersects with EMT transcriptional reprogramming. Patel et al. demonstrated that ATR prevented R-loop accumulation at EMT-related gene loci, thereby facilitating the transcriptional reprogramming necessary for EMT as well as tumor growth and metastasis. Tu et al. further uncovered a role for ATR in ECM stiffness–induced EMT, which was associated with an immunosuppressive tumor microenvironment. Together, these studies highlight important therapeutic implications for ATR targeting in the context of metastasis and therapy resistance.
Authors
Aida Mestre-Farrera, Zhimin Hu, Jing Yang
Abstract
Pancreatic β cells regulate glucose homeostasis through insulin secretion, but nutrient overload and genetic defects can trigger ER stress and apoptosis, contributing to type 2 diabetes. Within β cells, the kinases PERK, IRE1α, and ATF6 initiate the unfolded protein response (UPR) as a result of ER stress, a process that is constitutively suppressed under nonstress conditions by GRP78 binding to these proteins. To gain insight into the mechanisms of β cell death upon dysregulated ER stress, Sharma et al. used β cell–specific GRP78 knockout models, revealing that hyperactivation of the UPR promoted β cell death primarily through the IRE1α/JNK/p53 signaling pathway. Pharmacological inhibition of JNK improved β cell survival, increased insulin levels, and lowered blood glucose in multiple diabetic mouse models. These findings highlight JNK signaling as a promising therapeutic target for preserving β cell function.
Authors
Jonathan M. Palozzi, Pere Puigserver
Abstract
Myxomatous degeneration of the mitral valve (MDMV) is a common cardiovascular manifestation of Marfan syndrome (MFS), yet the role of lymphatic vessels in the disease progression remains unknown. In this Commentary, we discuss the study by Tan, Kume, and colleagues, which identifies defective lymphangiogenesis as a previously unrecognized driver of MDMV. Their work demonstrates that impaired lymphatic development and drainage promote valve inflammation through reduced ZFP36-mediated antiinflammatory signaling, whereas restoration of lymphatic function or pharmacological activation of ZFP36 with the FDA-approved drug FTY720 ameliorates disease progression. These findings establish lymphatic vessels as critical regulators of mitral valve homeostasis and support exploration of lymphatic-targeted therapeutic opportunities for MFS-associated valvular disease.
Authors
Yanna Tian, Kathleen M. Caron
Abstract
Cardiac macrophages (CMs) preserve homeostasis in the heart by clearing cellular debris and facilitating electrical conduction. During tissue injury, embryonically derived CMs (em-CMs) have traditionally been deemed beneficial for promoting tissue repair, whereas monocyte-derived CMs (mo-CMs) are considered detrimental, contributing to inflammation and tissue damage. However, Kasam et al. challenge this binary classification using cardiac-specific strategies to expand either em-CM or mo-CM populations. As expected, mice with cardiac-specific mo-CM expansion exhibited adverse outcomes following transverse aortic constriction (TAC). Surprisingly, mice with expanded em-CMs also showed a marked decline in cardiac function after TAC, which was associated with an unexpected interaction with mo-CMs. This deterioration was temporally regulated, occurring only if em-CMs were expanded before TAC induction. Together, these findings suggest that simplistic classification of CMs as either beneficial or harmful underestimates their complex roles in cardiac pathology, highlighting the need to reassess current views of macrophage function in heart injury.
Authors
Janmes Karunamurthy, Ziyi Li, Ajitha Thanabalasuriar
Abstract
The liver plays a major role in regulating the metabolic fate of lipids and facilitates lipid secretion to peripheral organs in the form of VLDLs or lipid storage in lipid droplets (LDs). Hepatic regulation of excess lipids profoundly influences the development of atherosclerosis; thus, uncovering the regulatory mechanisms underlying lipid storage and secretion pathways may reveal additional therapeutic targets. In this issue of the JCI, Lu et al. identified a pathway involving SEC16B, showing that this protein functions as a lipid-responsive regulator and mediates VLDL secretion and LD formation to maintain lipid homeostasis. They also demonstrated that a reduction in SEC16B reduced serum lipid levels and atherosclerotic plaque area in Ldlr–/– mice. These results indicate that SEC16B connects VLDL and LD metabolism, positioning SEC16B as a potential therapeutic avenue for atherosclerosis.
Authors
Hossein Ardehali
Abstract
Malignant cells must rapidly synthesize nucleotides to grow and proliferate. Antimetabolite chemotherapies throw a wrench in this process by administering decoy molecules resembling nucleotide precursors that cells cannot use, such as 6-mercaptopurine (6MP) and methotrexate. While this approach remains an essential tool in the treatment of lymphoblastic leukemias and B cell non-Hodgkin lymphomas, approximately 1 in 3 patients will eventually develop therapy-resistant malignancies. In this issue of the JCI, Yang et al. investigated the metabolic adaptations that enable therapy-resistant tumors to grow in the presence of these drugs. Using their previously described mouse model of MYC-driven large B cell lymphoma, they identified that increased expression of the vesicular oligopeptide and histidine transporter SLC15A3 drives dipeptide accumulation in therapy-resistant cells. In lieu of finding other ways to make more nucleotides, these adaptations force cell growth by boosting mTOR signaling. This cunning adaptation, however, is also a vulnerability that can be targeted clinically.
Authors
Carlos Carmona-Fontaine
Abstract
Type 1 regulatory (Tr1) T cells are a major source of IL-10–mediated immune regulation, yet their phenotypic definition and role in human disease remain incompletely understood. In this issue of the Journal of Clinical Investigation, Nideffer et al. provide insight into human Tr1 cells during pediatric Plasmodium falciparum (Pf) infection. The authors identified Tr1 cells as a major component of the malaria-specific CD4+ T cell response, producing both IL-10 and IFN-γ. They proposed that, in this context, Tr1 cells may be better identified by CD127 downregulation combined with CXCR6 expression than by other surface markers. Importantly, Tr1 cells exhibited suppressive function and were associated with reduced symptomatic disease but also with prolonged infection. Together, these findings refine current models of Tr1 cell identity and establish a more rigorous framework for marker validation using single-cell transcriptomics while highlighting the role of Tr1 cells in balancing immunity and immunopathology during infection.
Authors
Leonie Brockmann
Abstract
Metabolic dysfunction–associated steatohepatitis (MASH) affects 1.5%–6.5% of the global population, yet its mechanisms remain incompletely understood. Cholesterol overload is a key driver of MASH, suggesting that targeting cholesterol sensing may offer therapeutic benefits. In this issue, Deng et al. identified nuclear factor erythroid 2–related factor 1 (NFE2L1) as a critical regulator linking cholesterol sensing to VLDL-mediated lipid export. Mechanistically, NFE2L1 interacts with insulin-induced gene 1 (INSIG1) and promotes its degradation in hepatocytes. This cholesterol-dependent NFE2L1-INSIG1 interaction sustains SREBP activation and VLDL secretion to maintain hepatic and systemic lipid homeostasis. Moreover, the study by Deng et al. indicates that hepatic NFE2L1 overexpression decreases INSIG1 abundance and ameliorates MASH progression, highlighting its therapeutic potential.
Authors
Mengwei Zang, Yu Li
Abstract
Members of the type 2 histone lysine methyltransferase family (KMT2s) are key drivers of enhancer activation and are the most mutated group of epigenetic regulators in different cancer types. Within this family, KMT2C and KMT2D have the highest mutational incidence across various cancers. To evaluate their role in gastric cancer, Wang et al. developed a Pten deficiency–driven genetically engineered mouse model with inducible loss of Kmt2c and Kmt2d in gastric epithelial cells. Through extensive in vitro, in vivo, and in silico analyses, the authors revealed that the concomitant loss of Kmt2c and Kmt2d promotes gastric carcinogenesis while enhancing antigen presentation and sensitivity to immunotherapy and targeted approaches like mTOR inhibition, highlighting the tumor-suppressive roles of KMT2C/D in gastric cancer and uncovering a vulnerability for this dismal condition.
Authors
Nicole M. Peña Ruiz, Martin E. Fernandez-Zapico
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