Issue published December 8, 2025
- Volume 10, Issue 23
- Previous Issue
Guo et al.report that lipin1 plays a protective role in the heart following ischemic injury via preservation of lipid metabolism in ischemic cardiomyocytes. The cover shows neonatal rat cardiomyocytes (red) treated with stearic acid. Lipid droplets were stained with BODIPY (green), and nuclei were stained with DAPI (blue). Image credit: Jiaxi Guo.
On the cover: Myocardial lipin1 protects the heart against ischemic injury by preserving lipid homeostasis
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Research Articles
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Abstract
Mitochondrial dysfunction is a major mechanism of acute kidney injury (AKI), and increased circulating interleukin 6 (IL-6) is associated with systemic inflammation and death due to sepsis. We tested whether kidney mitochondrial DNA (mtDNA) contributes to IL-6 release in sepsis-associated AKI via Toll-like receptor 9 (TLR9). In a murine model of sepsis via cecal ligation and puncture (CLP), we used next-generation sequencing of plasma mtDNA to inform the design of optimal target sequences for quantification by droplet digital PCR, and to identify single-nucleotide polymorphisms (SNPs) to infer tissue origin. We found significantly higher concentrations of plasma mtDNA after CLP versus shams and that plasma mtDNA SNPs matched kidney SNPs more than other organs. Kidney mtDNA contributed directly to IL-6 and mtDNA release from dendritic cells in vitro and kidney mitochondria solution led to higher IL-6 concentrations in vivo. IL-6 release was mitigated by a TLR9 inhibitor. Finally, plasma mtDNA was significantly higher in septic patients with AKI compared with those without AKI and correlated significantly with plasma IL-6. We conclude that AKI contributes to increased circulating IL-6 in sepsis via mtDNA release. Targeting kidney mitochondria and mtDNA release are potential translational avenues to decrease mortality from sepsis-associated AKI.
Authors
Avnee J. Kumar, Katharine Epler, Jing Wang, Alice Shen, Negin Samandari, Mark L. Rolfsen, Laura A. Barnes, Gerald S. Shadel, Alexandra G. Moyzis, Alva G. Sainz, Karlen Ulubabyan, Kefeng Li, Kristen Jepsen, Xinrui Li, Mark M. Fuster, Roger G. Spragg, Roman Sasik, Volker Vallon, Helen Goodluck, Joachim H. Ix, Prabhleen Singh, Mark L. Hepokoski
×Abstract
Clear cell renal cell carcinomas (ccRCCs) are largely driven by HIF2α and are avid consumers of glutamine. However, inhibitors of glutaminase 1 (GLS1), the first step in glutaminolysis, have not shown benefit in phase III trials, and HIF2α inhibition, recently FDA approved for treatment of ccRCC, shows significant but incomplete benefits. This highlights the need to better understand the interplay between glutamine metabolism and HIF2α in ccRCC. Here, we report that glutamine deprivation rapidly redistributed GLS1 into isolated clusters within mitochondria in diverse cell types, but not in ccRCC. GLS1 clustering occurred rapidly within 1–3 hours, was reversible, was specifically triggered by reduced intracellular glutamate, and was dependent on mitochondrial fission. Clustered GLS1 markedly enhanced glutaminase activity and promoted cell death under glutamine-deprived conditions. HIF2α prevented GLS1 clustering, independently of its transcriptional activity, thereby maintaining low GLS activity and protecting ccRCC cells from glutamine-deprivation-induced cell death. Forced clustering of GLS1, using constitutively clustering mutants, restored high GLS activity, promoted apoptosis, and suppressed ccRCC tumor growth in vivo. These findings reveal multiple insights into cellular glutamine handling, including a previously unrecognized process by which HIF2α promotes ccRCC: by suppressing GLS1 clustering and maintaining low GLS activity. This mechanism provides a potential explanation for the lack of clinical efficacy of GLS inhibitors in ccRCC and suggests a therapeutic avenue to combine HIF2α inhibition with strategies that restore GLS1 clustering.
Authors
Wencao Zhao, Sara M. Demczyszyn, Nathan J. Coffey, Yanqing Jiang, Boyoung Kim, Schuyler Bowers, Caitlyn Bowman, Michael C. Noji, Cholsoon Jang, M. Celeste Simon, Zoltan Arany, Boa Kim
×Abstract
Impaired cardiac lipid metabolism has been reported to cause heart failure. Lipin1, a multifunctional protein, is a phosphatidate phosphatase that generates diacylglycerol from phosphatidic acid and a transcriptional cofactor that regulates lipid metabolism-related gene expression. Here, we investigated the roles of lipin1 in cardiac remodeling after myocardial infarction (MI). The expression levels of lipin1 significantly decreased in cardiomyocytes of the human failing heart and murine ischemic myocardium. Cardiomyocyte-specific Lpin1 knockout (cKO) mice showed left ventricle enlargement and reduced fractional shortening after MI, compared with control mice. This was accompanied by elevated cardiac fibrosis, accumulation of reactive oxygen species, and increased expression of inflammatory cytokines. In contrast, cardiomyocyte-specific Lpin1 overexpression (cOE) mice showed reduced fibrosis and inflammation and improved cardiac function compared with control mice. Cardiac lipid droplets (LDs) were reduced after MI in WT mouse hearts and were further downregulated in the hearts of cKO mice with a decrease in triacylglycerol and free fatty acid content, while cOE mice hearts exhibited increased LDs and lipid content. Expression levels of genes involved in fatty acid oxidation, such as Ppargc1a (PGC1A) and Acaa2, were decreased and increased in the MI hearts of cKO mice and cOE mice, respectively. These results suggest the protective role of lipin1 against ischemic injury by maintaining lipid metabolism in ischemic cardiomyocytes.
Authors
Jiaxi Guo, Kohei Karasaki, Kazutaka Ueda, Manami Katoh, Masaki Hashimoto, Toshiyuki Ko, Masato Ishizuka, Satoshi Bujo, Chunxia Zhao, Risa Kishikawa, Haruka Yanagisawa-Murakami, Hiroyuki Sowa, Bowen Zhai, Mutsuo Harada, Seitaro Nomura, Norihiko Takeda, Brian N. Finck, Haruhiro Toko, Issei Komuro
×Abstract
Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. During early sepsis, kinins are released and bind to B1 (BDKRB1) and B2 (BDKRB2) bradykinin receptors, but the involvement of these receptors in sepsis remains incompletely understood. This study demonstrated that the genetic deletion of Bdkrb2 had no significant impact on sepsis induced by cecal ligation and puncture (CLP) compared to wild-type (WT) mice. In contrast, Bdkrb1−/− mice subjected to CLP exhibited decreased lethality and bacterial load, associated with an increased influx of neutrophils into the peritoneal cavity, compared with WT mice. Neutrophils from CLP-Bdkrb1−/− mice partially restored CXCR2 expression and reduced the upregulation of P110γ observed in WT CLP neutrophils. Pharmacologic inhibition of BDKRB1 combined with imipenem treatment substantially improved survival compared with antibiotic therapy alone. In human neutrophils, stimulation with LPS led to the upregulation of BDKRB1 expression, and antagonism of BDKRB1 restored neutrophil migration in response to CXCL8. These findings identify BDKRB1 as an important modulator of neutrophil dysfunction in sepsis and a promising therapeutic target whose inhibition improves bacterial clearance, restores neutrophil migration, and increases the efficacy of antibiotic treatment.
Authors
Raquel Duque do Nascimento Arifa, Carolina Braga Resende Mascarenhas, Lívia Caroline Resende Rossi, Maria Eduarda Freitas Silva, Larissa M. Lucas, João Paulo Pezzini Barbosa, Daiane Boff, Brenda Gonçalves Resende, Lívia Duarte Tavares, Alesandra Corte Reis, Vanessa Pinho, Flavio Almeida Amaral, Caio Tavares Fagundes, Cristiano Xavier Lima, Mauro Martins Teixeira, Daniele G Souza
×Abstract
A distinguishing feature of older mesenchymal stem cells (MSCs) from bone marrow (BM) is the transition in their differentiation capabilities from osteoblasts to adipocytes. However, the mechanisms underlying these cellular events during the aging process remain unclear. We identified angiopoietin-like protein 8 (ANGPTL8), an adipokine implicated in lipid metabolism, that influenced the fate of MSCs in BM during skeletal aging. Our studies revealed that ANGPTL8 steered MSCs toward adipogenic differentiation, overshadowing osteoblastogenesis. Mice with overexpressed ANGPTL8 exhibited reduced bone mass and increased BM adiposity, while those with transgenic depletion of ANGPTL8 showed lowered bone loss and less accumulation of BM fat. ANGPTL8 influenced the BM niche of MSCs by inhibiting the Wnt/β-catenin signaling pathway. Partial inhibition of PPARγ rescued some aspects of the phenotype in MSCs with ANGPTL8 overexpression. Furthermore, treatment with an Angptl8 antisense oligonucleotide improved the phenotype of aging mice. Our research suggests that ANGPTL8 is a crucial regulator of senesence-related changes in the BM niche and the cell-fate switch of MSCs.
Authors
Yaming Guo, Zeqing Zhang, Junyu He, Peiqiong Luo, Zhihan Wang, Yurong Zhu, Xiaoyu Meng, Limeng Pan, Ranran Kan, Yuxi Xiang, Beibei Mao, Yi He, Siyi Wang, Yan Yang, Fengjing Guo, Hongbo You, Feng Li, Danpei Li, Yong Chen, Xuefeng Yu
×Abstract
IgA protects the body from invaders in the mucosal sites, but its role in allergic diseases, such as hay fever, is poorly understood. We demonstrate an increased susceptibility to cedar-pollen-induced hay fever associated with increasing pollen penetration into the body in IgA-deficient mice, indicating that IgA prevents pollen invasion in the mucosa. We identified bryostatin 1, an anticarcinogenic protein kinase Cδ (PKCδ) activator, as an IgA/IgE class-switching regulator in B cells. Bryostatin 1 enhanced IgA production through induction of germline transcript α (GLTα) via the PKCδ/MEK/ERK/RUNX1 pathway and suppressed IgE by reducing GLTε through the PKCδ/STAT5/ID2 pathway. Production of Th2 cytokines and eosinophil infiltration in the lungs was also reduced. Furthermore, hay fever alleviation by bryostatin 1 demonstrated diminished symptoms in mice in vivo 3 months subsequent to intranasal administration.
Authors
Naoki Morita, Kohta Yamamoto, Ryutaro Tamano, Peng Gao, Takahiro Nagatake, Takenori Inomata, Tianxiang Huang, Yasuhiro Yamada, Takahiro Adachi, Manabu Sugai, Keiichi I. Nakayama, Hirotatsu Kojima, Reiko Shinkura
×Abstract
Anthracycline chemotherapy, widely used in cancer treatment, poses a significant risk of cardiotoxicity that results in functional decline. Current diagnostic methods poorly predict cardiotoxicity because they do not detect early damage that precedes dysfunction. Positron emission tomography (PET) is well suited to address this need when coupled with suitable imaging biomarkers. We used PET to evaluate cardiac molecular changes in male C57BL/6J mice exposed to doxorubicin (DOX). These mice initially developed cardiac atrophy, experienced functional deficits within 10 weeks of treatment, and developed cardiac fibrosis by 16 weeks. Elevated cardiac uptake of [68Ga]Ga-FAPI-04, a PET tracer targeting fibroblast activation protein α (FAP), was evident by 2 weeks and preceded the onset of functional deficits. Cardiac PET signal correlated with FAP expression and activity as well as other canonical indicators of cardiac remodeling. By contrast, cardiac uptake of [18F]DPA-714 and [18F]MFBG, which target translocator protein 18 kDa and the norepinephrine transporter, respectively, did not differ between the DOX animals and their controls. These findings identify FAP as an early imaging biomarker for DOX-induced cardiac remodeling in males and support the use of FAP PET imaging to detect some cancer patients at risk for treatment-related myocardial damage before cardiac function declines.
Authors
Chul-Hee Lee, Onorina L. Manzo, Luisa Rubinelli, Sebastian E. Carrasco, Sungyun Cho, Thomas M. Jeitner, John Babich, Annarita Di Lorenzo, James M. Kelly
×Abstract
The lung’s mechanosensitive immune response to alveolar overdistension impedes ventilation therapy for hypoxemic respiratory failure. Though mechanistically unclear, the prevailing hypothesis is that the immune response results when alveolar overdistension stretches alveolar macrophages (AMs). Since this hypothesis is untested in live lungs, we optically imaged live mouse alveoli to detect alveolus-adherent, sessile AMs that communicate with the alveolar epithelium through connexin 43-containing (Cx43-containing) gap junctions. Alveolar hyperinflation did not stretch the AMs, but it increased AM Ca2+. AM-specific Cx43 deletion blocked the Ca2+ response, as well as lung injury due to mechanical ventilation at high tidal volume (HTV). HTV-induced injury was also inhibited by AM-targeted delivery of liposomes containing the inhibitor of endosomal Ca2+ release, xestospongin C. We conclude Cx43- and Ca2+-dependent AM-epithelium interactions determine the lung’s mechanosensitive immunity, providing a basis for therapy for ventilator-induced lung injury.
Authors
Liberty Mthunzi, Mohammad N. Islam, Galina A. Gusarova, Brian Karolewski, Sunita Bhattacharya, Jahar Bhattacharya
×Abstract
Glycolysis fuels cytotoxic allogeneic T cells in acute graft-versus-host disease (aGvHD), but the downstream role of glucose metabolism in modulating aGvHD remains unclear. Targeting glycolysis or glucose receptors is toxic. Therefore, we explored alternative glucose-dependent pathways, focusing on the pentose phosphate pathway (PPP). Single-cell RNA sequencing revealed PPP upregulation in allogeneic T cells during allogeneic hematopoietic cell transplantation (allo-HCT). We showed that donor T cell deficiency in 6-phosphogluconate dehydrogenase (6PGD), the second rate-limiting enzyme in the PPP, significantly reduced aGvHD severity and mortality in murine models. Functional assays demonstrated that PPP blockade led to proliferation arrest without inducing apoptosis. PPP blockade shifted T cell metabolism away from T cell dependency on glycolysis for rapid T cell proliferation. Pharmacological inhibition of the PPP through 6PGD blockade with 6-aminonicotinamide (6AN) effectively reduced aGvHD severity, like donor 6PGD-deficient T cells in an allogeneic aGvHD model. Similarly, 6AN reduced xenogeneic GvHD lethality. 6PGD inhibition preserved the graft-versus-tumor (GvT) effect, with the generation of a small subset of granzyme Bhi effector T cells with potent antitumor activity. These findings highlight the PPP as a key regulator of allogeneic T cell proliferation and differentiation and identify 6PGD as a promising therapeutic target to mitigate aGvHD severity while preserving beneficial GvT effects.
Authors
Saeed Daneshmandi, Eun Ko, Qi Yan, Jee Eun Choi, Prashant K. Singh, Richard M. Higashi, Andrew N. Lane, Teresa W.M. Fan, Jingxin Qiu, Sophia Hani, Keli L. Hippen, Jianmin Wang, Philip L. McCarthy, Bruce R. Blazar, Hemn Mohammadpour
×Abstract
BACKGROUND Suboptimal fetal growth (SFG), being born small for gestational age (SGA), and catch-up (CU) growth are, individually and together, linked to cardiometabolic risks. However, not all develop adverse outcomes. This study aimed to validate a transcriptomic signature to identify individuals at greatest cardiometabolic risk.METHODS Using National Heart, Lung and Blood Institute (NHLBI) criteria to define cardiometabolic risk, healthy and prehypertensive 17-year-olds were identified in the Avon Longitudinal Study of Parents and Children (ALSPAC) (UK) childhood cohort. Epigenomic and transcriptomic differences were analyzed. A hypergraph identified functionally related genes, which were used in random forest classification to predict prehypertensive phenotypes. The BabyGRO (UK) cohort included 80 children aged 3–7 years, born at term following pregnancies with SFG risks. Anthropometric and cardiometabolic markers and transcriptomic profiles were collected, fetal and childhood weight trajectories and their relationship to cardiometabolic markers were assessed, and transcriptome was used for prediction.RESULTS Individuals with CU-SGA in ALSPAC were 1.6 times more likely than all others to be prehypertensive at 17 years (P < 1 × 10–5). A 42-gene hypergraph cluster was highly predictive of prehypertension (AUC 0.984, error rate 5.4%). In BabyGRO, 20 of these genes accurately predicted higher systolic blood pressure (AUC 0.971, error rate 3.6%). This transcriptomic signature could help identify children with adverse pre- and postnatal growth who may develop prehypertension.CONCLUSION A blood transcriptomic signature exists in childhood which distinguishes those at risk of adult cardiometabolic disease among children with adverse pre- and postnatal growth.TRIAL REGISTRATION Regional ethics committee reference 17/NW/0153, IRAS project ID 187679.FUNDING Centre grant to the Maternal and Fetal Health Research Centre by Tommy’s The Pregnancy and Baby Charity, Child Growth Foundation, European Research Council funding as part of the Health and Environment-wide Associations based on Large Population Surveys (HEALS) study
Authors
Reena Perchard, Terence Garner, Philip G. Murray, Amirul Roslan, Lucy E. Higgins, Edward D. Johnstone, Adam Stevens, Peter E. Clayton
×Abstract
Genetic variants in lipid metabolism influence the risk of developing metabolic dysfunction–associated steatotic liver disease (MASLD), cirrhosis, and end-stage liver disease (ESLD). The mechanisms by which these variants drive disease are poorly understood. Because of the PNPLA3-I148M variant’s strong correlation with all stages of the MASLD spectrum and the lack of tractable therapeutic targets, we sought to understand its impact on cellular function and liver metabolism. Primary human hepatocytes (HAHs) and induced pluripotent stem cell–derived (iPSC-derived) hepatocytes (iHeps) from healthy individuals possessing the PNPLA3-I148M mutation were characterized for changes in lipid metabolism, cellular stress, and survival. Using lipidomics, metabolomics, stable isotope tracing, and flux propensity analysis, we created a comprehensive metabolic profile of the changes associated with the PNPLA3-I148M variant. Functional analysis showed that the presence of the PNPLA3-I148M variant increased endoplasmic reticulum stress, mitochondrial dysfunction, and peroxisomal β-oxidation, ultimately leading to cell death via ferroptosis. Nutritional interventions, ferroptosis-specific inhibitors, and genetic approaches modulating GPX4 activity in PNPLA3-I148M HAHs and iHeps decreased programmed cell death. Our findings indicate that therapies targeting ferroptosis in patients carrying the PNPLA3-I148M variant could affect the development of MASLD and ESLD and highlight the utility of iPSC-based models for the study of genetic contributions to hepatic disorders.
Authors
Rodrigo M. Florentino, Olamide Animasahun, Nils Haep, Minal Nenwani, Kehinde Omoloja, Leyla Nurcihan Altay, Abhinav Achreja, Kazutoyo Morita, Takashi Motomura, Ricardo Diaz-Aragon, Lanuza A.P. Faccioli, Yiyue Sun, Zhenghao Liu, Zhiping Hu, Bo Yang, Fulei Wuchu, Ajay Shankaran, Miya Paserba, Annalisa M. Baratta, Shohrat Arazov, Zehra N. Kocas-Kilicarslan, Noah Meurs, Jaideep Behari, Edgar N. Tafaleng, Jonathan Franks, Alina Ostrowska, Takahiro Tomiyama, Kyohei Yugawa, Akinari Morinaga, Zi Wang, Kazuki Takeishi, Dillon C. Gavlock, Mark Miedel, D. Lansing Taylor, Ira J. Fox, Tomoharu Yoshizumi, Deepak Nagrath, Alejandro Soto-Gutierrez
×Abstract
BACKGROUND Blood donation increases the risk of iron deficiency, but its effect on brain iron, myelination, and neurocognition remains unclear.METHODS This ancillary study enrolled 67 iron-deficient blood donors, 19–73 years of age, participating in a double-blind, randomized trial. After donating blood, positive and negative susceptibility were measured using quantitative susceptibility mapping (QSM) MRI to estimate brain iron and myelin levels, respectively. Furthermore, neurocognitive function was evaluated using the NIH Toolbox, and neural network activation patterns were assessed during neurocognitive tasks using functional MRI (fMRI). Donors were randomized to i.v. iron repletion (1 g iron) or placebo, and outcome measures repeated approximately 4 months later.RESULTS Iron repletion corrected systemic iron deficiency and led to trends toward increased whole brain iron (P = 0.04) and myelination (P = 0.02), with no change in the placebo group. Although overall cognitive performance did not differ significantly between groups, iron-treated participants showed improved engagement of functional neural networks (e.g., memory pattern activation during speed tasks, P < 0.001). Brain region-specific changes in iron and myelin correlated with cognitive performance: iron in the putamen correlated with working memory scores (P < 0.01), and thalamic myelination correlated with attention and inhibitory control (P < 0.01).CONCLUSION Iron repletion in iron-deficient blood donors may influence brain iron, myelination, and function, with region-specific changes in iron and myelination linked to distinct cognitive domains.REGISTRATION ClinicalTrials.gov NCT02990559FUNDING This work was funded by the NIH.
Authors
Eldad A. Hod, Christian Habeck, Hangwei Zhuang, Alexey Dimov, Pascal Spincemaille, Debra Kessler, Zachary C. Bitan, Yona Feit, Daysha Fliginger, Elizabeth F. Stone, David Roh, Lisa Eisler, Stephen Dashnaw, Elise Caccappolo, Donald J. McMahon, Yaakov Stern, Yi Wang, Steven L. Spitalnik, Gary M. Brittenham
×Abstract
Obesity and type 2 diabetes (T2D) are metabolic diseases with increasing prevalence worldwide. Obesity often leads to T2D. Insulin resistance and impaired β cell function contribute to the onset of hyperglycemia. Previously, we reported that ablation of Gc, encoding a secreted protein with a primary role in vitamin D transport, improved pancreatic β cell function in models of diet-induced insulin resistance. Here, we show that Gc ablation had systemic insulin-sensitizing effects to prevent weight gain, hyperglycemia, and glucose intolerance; lower nonesterified fatty acids and triglycerides; and augment glucose uptake in skeletal muscle and adipose in male mice fed a high-fat diet. Interestingly, weight loss in Gc-ablated mice resulted from selective fat mass loss with preserved lean mass. Moreover, acute Gc inhibition prevented glucose intolerance caused by high-fat feeding. The data suggest that Gc inhibition can increase insulin production in β cells and insulin action in peripheral tissues, while reducing fat mass.
Authors
Richard Gill, Taiyi Kuo
×Abstract
Mammalian skin wounds typically heal with a scar, characterized by fibrotic tissue that disrupts original tissue architecture and function. Therapies that limit fibrosis and promote regenerative healing remain a major unmet clinical need. Rosemary extract, particularly in the form of topical oils and creams, has gained widespread public attention for its purported wound-healing properties. However, its efficacy and mechanism of action remain poorly understood. We show in adult wound healing mouse models that an ethanol-based rosemary extract accelerates the speed of wound healing and mitigates fibrosis. Mechanistically, we identify that carnosic acid, a major bioactive component of rosemary leaves, activates the transient receptor potential ankyrin 1 (TRPA1) nociceptor on cutaneous sensory neurons to enhance tissue regeneration. Mice lacking TRPA1 in sensory neurons do not exhibit these pro-regenerative responses, confirming its role as a critical mediator. Together, these findings suggest that topical rosemary extract may represent an effective and accessible therapeutic approach to improve skin repair outcomes.
Authors
Emmanuel Rapp, Jiayi Pang, Borna Saeednia, Stephen Marsh Prouty, Christopher A. Reilly, Thomas H. Leung
×Abstract
Pancreatic ductal adenocarcinoma (PDAC) is a rapidly metastasizing cancer characterized by a dense desmoplastic stroma composed of extracellular matrix (ECM) proteins, which complicates treatment. Upon stimulation, pancreatic stellate cells (PSCs) differentiated into cancer-associated fibroblasts (CAFs) that are the source of ECM and cytokines in PDAC. We previously reported that mechanical stress activates PSCs and induces fibrosis through mechanical ion channel PIEZO1-mediated TRPV4 channel activation, but its role in PDAC remains unclear. Here we report that pathological activation of PIEZO1 differentiated human PSCs into an inflammatory CAF phenotype that expresses chemoresistance and cancer stemness markers CD10 and GPR77. In an orthotopic PDAC model, TRPV4-KO mice exhibited a significant reduction in tumor size, circulating inflammatory cytokines, tissue inhibitor of metalloproteinases-1 (TIMP1), and premetastatic niche markers, serum amyloid A (SAA) proteins. A similar trend was observed in mice lacking functional PIEZO1 in PSCs. The livers of TRPV4-KO mice exhibited fewer cancer cell microlesions, lacked macrotumors, produced lower levels of inflammatory protein S100A8, and developed fewer inflammatory cell clusters. In orthotopic and genetically engineered models of PDAC, these mice also had improved survival, suggesting that blocking TRPV4 channels may be a promising therapeutic target for PDAC.
Authors
Joelle M.-J. Romac, Sandip M. Swain, Nidula Mullappilly, Bandana Bindhani, Rodger A. Liddle
×Abstract
Solute carrier family 26, member 9 (SLC26A9) is an epithelial chloride channel that was identified as a genetic modifier of disease severity of cystic fibrosis (CF) and other chronic muco-obstructive lung diseases. However, data on the in vivo role of SLC26A9 function in lung health and disease remain limited. Here, we investigated the effect of genetic deletion of Slc26a9 (Slc26a9–/–) on the pulmonary phenotype of neonatal mice. We found that lack of Slc26a9 causes severe neonatal respiratory distress with high mortality. Histology, immunohistochemistry, and micro-computed tomography imaging studies identified airway obstruction with MUC5B-positive mucus plugs in neonatal Slc26a9–/– mice. Bioelectric measurements demonstrated a reduced transepithelial potential difference indicative of reduced chloride secretion across tracheal explants of neonatal Slc26a9–/– compared with WT mice. In addition, neonatal Slc26a9–/– mice displayed hypoxic degeneration of airway epithelial cells associated with sterile neutrophilic airway inflammation. Collectively, our data show that SLC26A9-mediated chloride secretion is critical for proper mucociliary clearance, respiratory function, and survival after birth, and identify a role for SLC26A9 in neonatal adaptation during the transition from fetal to neonatal life.
Authors
Pamela Millar-Büchner, Johanna J. Salomon, Julia Duerr, Stephan Spahn, Pinelopi Anagnostopoulou, Willi L. Wagner, Mark O. Wielpütz, Hermann-Josef Groene, Anita Balázs, Marcus A. Mall
×Abstract
High-affinity antibody production depends on CD4+ T follicular helper (Tfh) cells. In humans, peripheral blood Tfh cells are heterogenous, as evidenced by differential expression of the chemokine receptors CXCR3 and CCR6, which to date have served to classify 3 subsets, pTfh1, pTfh2, and pTfh17. Although pTfh1 responses dominate during blood-stage Plasmodium infections, a clear association with protective antibody responses remains to be described. We hypothesized that pTfh cells exhibit greater phenotypic and functional heterogeneity than described by CXCR3/CCR6 and that more nuanced pTfh subsets play distinct roles during Plasmodium infection. We mapped pTfh cell heterogeneity in healthy individuals prior to and during controlled human malaria infection (CHMI) using parallel single-cell RNA-Seq and VDJ-Seq. We uncovered 2 pTfh1 subsets or differential phenotypic states, distinguishable by CCR7 expression. Prior to infection, Tfh1-CCR7– cells exhibited higher baseline expression of inflammatory cytokines and genes associated with cytotoxicity. Tfh1-CCR7+ cells had higher germinal center signatures. Indeed, during CHMI, Tfh1-CCR7+, Tfh1-CCR7–, and Tfh2 cells all clonally expanded and became activated. However, only Tfh1-CCR7+ and Tfh2 cells positively associated with protective antibody production. Hence, our data reveal further complexity among human Tfh cells and highlight 2 distinct subsets associated with antibody-mediated immunity to malaria.
Authors
Megan S.F. Soon, Damian A. Oyong, Nicholas L. Dooley, Reena Mukhiya, Zuleima Pava, Dean W. Andrew, Jessica R. Loughland, James S. McCarthy, Jo-Anne Chan, James G. Beeson, Christian R. Engwerda, Ashraful Haque, Michelle J. Boyle
×Abstract
The biological age of organs may better quantify risk for health deterioration compared with chronological age. We investigated organ-specific aging patterns in a community-based cohort and assessed the associations with adverse health outcomes. Biological ages of 11 organs were estimated for 11,757 participants of the Atherosclerosis Risk in Communities (ARIC) study (55.6% women, mean age, 57.1 years) using a circulating protein–based model. Older organ ages were significantly associated with related adverse outcomes, even after accounting for chronological age; for example, older arteries and hearts were associated with an increased risk for coronary heart disease (CHD; hazard ratio [HR] per 5-year-higher age gap, 1.22; 95% CI [1.13–1.31] and 1.16 [1.07–1.26], respectively, and older lungs with lung cancer (HR 1.12 [1.09–1.16]). Hierarchical agglomerative clustering based on organ ages revealed 3 patient phenotypes: those with older organs, normal/slightly older organs, and younger organs. The patients with older organs were at higher risk for cancer (HR 1.19; 95% CI [1.08–1.31]), death (HR 1.75 [1.64–1.86]), end-stage kidney disease (HR 6.12 [4.65–8.06]), CHD (HR 1.21 [1.06–1.38]), heart failure (HR 1.92 [1.73–2.13]), infection (HR 1.56 [1.44–1.68]), and stroke (HR 1.36 [1.16–1.61]). Proteomic organ aging signatures demonstrated significant associations with multiple adverse health outcomes and may be useful for health risk identification.
Authors
Celina S. Liu, Wan-Jin Yeo, Aditya Surapaneni, B. Gwen Windham, Hamilton S.-H. Oh, Anna Prizment, Sanaz Sedaghat, Pascal Schlosser, Eugene P. Rhee, Sushrut S. Waikar, Josef Coresh, Keenan A. Walker, Morgan E. Grams
×Abstract
Elite controllers (ECs) maintain undetectable levels of plasma viremia in the absence of treatment, but small reservoirs of replication-competent proviruses persist in the vast majority of these persons. We longitudinally studied paired blood and inguinal lymph node samples (LNMC) from 2 ECs to better characterize distinguishing features of viral reservoir cell dynamics in ECs. In both participants, we observed a 7- to 10-fold lower frequency of intact proviruses in LNMC samples relative to reservoir cells circulating in blood. The landscape of intact proviruses in both tissue compartments was dominated by shared large clones that were frequently integrated in noncoding DNA regions, but the frequency and diversity of intact proviruses was more limited in LNMCs. Of note, over 9–10 years of longitudinal follow-up, a 3- to 18-fold reduction of intact proviruses was observed. Together, these data support the hypothesis that viral reservoirs in EC blood and lymphoid tissues are under strong, likely immune-mediated selection pressure.
Authors
Samantha K. Marzi, Chloé M. Naasz, Leah Carrere, Carmen Gasca Capote, Isabelle C. Roseto, Ce Gao, Matthias Cavassini, Andrea Mastrangelo, Mathias Lichterfeld, Matthieu Perreau, Xu G. Yu
×Abstract
Angiopoietin-like 3 (ANGPTL3) is a major regulator of lipoprotein metabolism. ANGPTL3 deficiency results in lower levels of triglycerides, LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C), and may protect from cardiovascular disease. ANGPTL3 oligomerizes with ANGPTL8 to inhibit lipoprotein lipase (LPL), the enzyme responsible for plasma triglyceride hydrolysis. Independently of ANGPTL8, oligomers of ANGPTL3 can inhibit endothelial lipase (EL), which regulates circulating HDL-C and LDL-C levels through the hydrolysis of lipoprotein phospholipids. The N-terminal region of ANGPTL3 is necessary for both oligomerization and lipase inhibition. However, our understanding of the specific residues that contribute to these functions is incomplete. In this study, we performed mutagenesis of the N-terminal region to identify residues important for EL inhibition and oligomerization. We also assessed the presence of different ANGPTL3 species in human plasma. We identified a motif important for lipase inhibition, and protein structure prediction suggested that this region interacted directly with EL. We also found that recombinant ANGPTL3 formed a homotrimer and was unable to inhibit EL activity when trimerization was disrupted. Surprisingly, we observed that human plasma contained more monomeric ANGPTL3 than trimeric ANGPTL3. An important implication of these findings is that previous correlations between circulating ANGPTL3 and circulating triglyceride-rich lipoproteins need to be revisited.
Authors
Sydney G. Walker, Yan Q. Chen, Kelli L. Sylvers-Davie, Alex Dou, Eugene Y. Zhen, Yuewei Qian, Yi Wen, Mariam Ehsani, Sydney Smith, Rakshya Thapa, Maxwell J. Mercer, Lucy Langmack, Bharat Raj Bhattarai, Michael Ploug, Robert J. Konrad, Brandon S.J. Davies
×Abstract
Recombinant hepatitis B surface antigen (rHBsAg) vaccine with various adjuvants fails to break T and B cell tolerance in hosts with chronic hepatitis B (CHB). This study aims to explore the mechanisms to break immune tolerance that allows the host to respond to rHBsAg, achieving a cure for CHB. We engineered an anti–PD-L1–IFN-α (aPD-L1–IFN-α) heterodimeric fusion protein to allow rHBsAg to rejuvenate T and B cell responses in hepatitis B virus–tolerant (HBV-tolerant) mice. S.c. coimmunization with aPD-L1–IFN-α and rHBsAg significantly enhanced antigen uptake and maturation of both macrophage and dendritic cell (DC) subsets in draining lymph nodes. Macrophages drove early B cell activation, while cDC1s primed CD8+ T cells, breaking tolerance and leading to both B cell and cytotoxic T lymphocyte (CTL) differentiation. This strategy elicited not only anti-HBsAg neutralizing antibodies but also HBsAg-specific CD8+ T cell responses, achieving a functional cure without systemic toxicity. The efficacy of the aPD-L1–IFN-α adjuvant depended on both PD-L1 cis-targeting and IFN-α receptor signaling in antigen-presenting cells. These findings establish aPD-L1–IFN-α as a translatable adjuvant to break the strong tolerance induced by CHB, providing a dual-pathway strategy to induce HBV-specific T and B cell responses.
Authors
Chao-Yang Meng, Yong Liang, Longxin Xu, Hongjia Li, Jingya Guo, Hairong Xu, Fan Wang, Yang-Xin Fu, Hua Peng
