Identification and regulation of circulating tumor-TCR-matched cytotoxic CD4⁺ lymphocytes by KLRG1 in bladder cancer

• Text
• PDF

Abstract

While cytotoxic CD4+ tumor-infiltrating lymphocytes have anticancer activity in patients, whether these can be noninvasively monitored and how these are regulated remains obscure. By matching single cells with T cell receptors (TCRs) in tumor and blood of patients with bladder cancer, we identified distinct pools of tumor-matching cytotoxic CD4+ T cells in the periphery directly reflecting the predominant antigenic specificities of intratumoral CD4+ tumor-infiltrating lymphocytes. On one hand, the granzyme B–expressing (GZMB-expressing) cytotoxic CD4+ subset proliferated in blood in response to PD-1 blockade but was separately regulated by the killer cell lectin-like receptor G1 (KLRG1), which inhibited their killing by interacting with E-cadherin. Conversely, a clonally related, GZMK-expressing circulating CD4+ population demonstrated basal proliferation and a memory phenotype that may result from activation of GZMB+ cells, but was not directly mobilized by PD-1 blockade. As KLRG1 marked the majority of circulating tumor-TCR-matched cytotoxic CD4+ T cells, this work nominates KLRG1 as a means to isolate them from blood and provide a window into intratumoral CD4+ recognition, as well as a putative regulatory receptor to mobilize the cytolytic GZMB+ subset for therapeutic benefit. Our findings also underscore ontogenic relationships of GZMB- and GZMK-expressing populations and the distinct cues that regulate their activity.

Authors

Serena S. Kwek, Hai Yang, Tony Li, Arielle Ilano, Eric D. Chow, Li Zhang, Hewitt Chang, Diamond Luong, Averey Lea, Matthew Clark, Alec Starzinski, Yimin Shi, Elizabeth McCarthy, Sima Porten, Maxwell V. Meng, Chun Jimmie Ye, Lawrence Fong, David Y. Oh

T cell phenotype and clonality changes in myeloma patients with short overall survival

• Text
• PDF

Abstract

Overall survival (OS) in multiple myeloma (MM) varies between a couple of months to more than 20 years, influenced by tumor characteristics, the tumor microenvironment (TME), and patient factors such as age and frailty. We analyzed sequential BM samples from 45 MM patients with OS less than 3 years versus more than 8 years using mass cytometry and bulk TCRβ sequencing. Patients with long OS demonstrated stability in the TME and T cell environments, while those with short OS had significant changes at relapse, including fewer T cells, increased Tregs, and more activated and exhausted CD8+ T cells. Notably, higher programmed cell death 1 expression in CD8+ T cells at diagnosis correlated with short OS. Additionally, short-OS patients exhibited a more monoclonal T cell environment at relapse, with abundance of hyperexpanded clones. These findings reveal distinct immune cell differences between patients with short and long OS.

Authors

Alenka Djarmila Behsen, Esten Nymoen Vandsemb, Tobias Schmidt Slørdahl, Karen Dybkær, Maja Zimmer Jakobsen, Muhammad Kashif, Johan Lund, Vincent Luong, Astrid Marta Olsnes, Anders Waage, Anne Marit Sponaas, Kristine Misund

Virus-induced RGMa expression drives neurodegeneration in HTLV-1–associated myelopathy

• Text
• PDF

Abstract

Human T-lymphotropic virus type 1–associated (HTLV-1–associated) myelopathy (HAM, also known as tropical spastic paraparesis) is a rare neurodegenerative disease with largely elusive molecular mechanisms, impeding targeted therapeutic advancements. This study aimed to identify the critical molecule responsible for neuronal damage in HAM, its source, and the regulatory mechanisms controlling its expression. Utilizing patient-derived cells and established cell lines, we discovered that HTLV-1 Tax, in conjunction with specificity protein 1 (Sp1), enhanced the expression of repulsive guidance molecule A (RGMa), a protein known to contribute to neuronal damage. RGMa expression was specifically upregulated in HTLV-1–infected cells from patients with HAM, particularly in those expressing HTLV-1 Tax. Furthermore, in CD4+ cells from patients with HAM, the level of H3K27me3 methylation upstream of the RGMA gene locus was reduced, making RGMA more prone to constitutive expression. We demonstrated that HTLV-1–infected cells in HAM inflict neuronal damage via RGMa. Crucially, the neutralizing antibody against RGMa, unasnemab (MT-3921), effectively mitigated this damage in a dose-responsive manner, highlighting RGMa’s pivotal role in neuronal damage and its potential as a therapeutic target for alleviating neuronal damage in HAM.

Authors

Natsumi Araya, Makoto Yamagishi, Makoto Nakashima, Naomi Asahara, Kazuhiro Kiyohara, Satoko Aratani, Naoko Yagishita, Erika Horibe, Izumi Ishizaki, Toshiki Watanabe, Tomoo Sato, Kaoru Uchimaru, Yoshihisa Yamano

Development of rat and mouse models of heme-iron absorption

• Text
• PDF

Abstract

Heme iron (HI), derived principally from hemoglobin (Hb) in animal foods, is a highly bioavailable source of dietary iron for humans. Despite several decades of focused research, however, molecular mechanisms governing HI absorption remain undefined. Previous studies in mice and rats have not produced a consensus, definitive model of efficient HI absorption/utilization. We hypothesized that a nutritional approach, using semipurified, HI-containing diets, could be utilized to establish a tractable rodent model of HI absorption that could ultimately be employed to test the roles of receptors, transporters, and enzymes using genetic engineering technology. Experiments were designed to assess HI utilization by feeding animals AIN-93G–based, HI-enriched experimental diets formulated with lyophilized porcine RBCs, containing approximately 85% HI and 15% nonheme iron (NHI). Total iron was within the physiological range (50–75 ppm) and precisely matched NHI control diets containing ferrous sulfate were utilized as comparators. Notably, in Sprague-Dawley (S-D) rats and C57BL/6 (B6) mice, dietary HI effectively (a) resolved iron-deficiency anemia; (b) supported normal pregnancy, lactation, and neonatal development; and (c) contributed to iron loading in Hamp-KO mice and rats (modeling hereditary hemochromatosis). A nutritional paradigm has thus been established that facilitates investigation into mechanisms of HI absorption by S-D rats and B6 mice.

Authors

Jennifer K. Lee, Yue He, Shireen R.L. Flores, Regina R. Woloshun, Xiaoyu Wang, Jacob S. Shine, Pearl O. Ebea-Ugwuanyi, Sitara Sriram, Melissa Fraga, Sean Zhu, Yang Yu, Iqbal Hamza, James F. Collins

CD154:CD11b blockade enhances CD8⁺ T cell differentiation during infection but not transplantation

• Text
• PDF

Abstract

CD154 is a promising target for immunosuppression in transplantation, autoimmunity, and inflammatory diseases. We previously identified CD11b as a novel alternative receptor for CD154 during alloimmunity. However, the impact of specific CD154:CD11b blockade on immune responses to infection has not been well characterized. Here, we have shown that in contrast with its immunosuppressive effect on graft-specific CD8+ T cells, CD154:CD11b blockade unexpectedly improved both the quantity and quality of murine herpesvirus-68–specific CD8+ T cells as measured by an increase in tetramer-positive KLRG1loCD127hi memory precursor effector cells. The differential effect of CD154:CD11b blockade on graft- versus virus-specific CD8+ T cells was underpinned by differences in phosphorylated S6 downstream of mTOR complex 1; however, differential expression of key transcription factors Eomes and TCF-1 was dictated by the type of antigen stimulus. These data demonstrate that priming conditions play an important role in determining the outcome of immunotherapy and suggest that specific inhibition of CD154:CD11b interactions could be effective for suppressing alloimmune responses while maintaining protective immunity to minimize infectious complications following transplantation.

Authors

Katie L. Alexander, Kelsey B. Bennion, Danya Liu, Mandy L. Ford

FTO inhibition enhances the therapeutic index of radiation therapy in head and neck cancer

• Text
• PDF

Abstract

Despite aggressive chemoradiation treatment, the overall survival rate for patients with HPV– head and neck squamous cell carcinoma (HNSCC) remains poor, highlighting the urgent need for more effective drug-radiotherapy combinations to improve the therapeutic index of radiation therapy (RT). The fat mass and obesity-related gene (FTO) is emerging as a promising cancer therapeutic target; however, its role in the RT response has been underexplored. In our study, we found that both genetic and pharmacologic inhibition of FTO enhanced the efficacy of RT in human and mouse HNSCC tumor xenografts. Mechanistically, inhibition of FTO improved the RT response in HPV– HNSCC cells, which was associated with increased DNA damage, reduced efficiency of homology directed repair, and decreased formation of RAD51 homolog 1 (RAD51) foci. Importantly, pharmacologic inhibition of FTO did not exacerbate radiation-induced oral mucositis, a significant normal-tissue toxicity associated with HNSCC RT. In summary, our results indicate a role for FTO in regulating homologous recombination while identifying FTO as a potential therapeutic target to enhance the therapeutic index of RT in HPV– HNSCC treatment.

Authors

Lu Ji, Leighton Pu, Jinglong Wang, Hongbin Cao, Stavros Melemenidis, Subarna Sinha, Li Guan, Eyiwunmi E. Laseinde, Rie von Eyben, Sara A. Richter, Jin-Min Nam, Christina Kong, Kerriann M. Casey, Edward E. Graves, Richard L. Frock, Quynh Thu Le, Erinn B. Rankin

Cellular immunophenotyping in human and primate tissues during healthy conditions and Ebola and Nipah infections

• Text
• PDF

Abstract

We developed a 29-color spectral cytometry panel to enhance nonhuman primate (NHP) models for cross-reactive immunophenotyping. This panel is suitable for biosafety level 4 (BSL-4) viruses and can be used with both human and NHP samples in BSL-2 research settings. Tissues from humans, rhesus monkeys (RhMs), crab-eating macaques (CEMs), and green monkeys (GMs) were stained with a 29-color immunophenotyping panel requiring only 2 clone substitutions. Comparable staining was observed for all samples. Unbiased analysis showed acceptable overlap in T cell phenotypes across samples, with differences in human and NHP B cells and granulocytes. In CEMs, most circulating CD8+ T cells were from effector memory cells, with significantly higher levels than in humans, RhMs, and GMs. Analysis of samples from various anatomical sites revealed distinct location-specific phenotypes. In Nipah virus–exposed animals, splenocytes showed a substantial increase in IgM+ B cells and a reduction in effector memory CD8+ T cells compared with unexposed controls. Lymph nodes from Ebola virus–exposed animals showed a loss of CXCR3+CD8+ T cells versus unexposed controls. This panel may guide the development of additional multicolor panels in preclinical and clinical settings and may increase understanding of the pathogenesis of diseases caused by emerging and reemerging viruses.

Authors

Andrew P. Platt, Bobbi Barr, Anthony Marketon, Rebecca Bernbaum, Deja F.P. Rivera, Vincent J. Munster, Daniel S. Chertow, Michael R. Holbrook, Scott M. Anthony, Bapi Pahar

LRP1 regulates asthmatic airway smooth muscle proliferation through FGF2/ERK signaling

• Text
• PDF

Abstract

Airway smooth muscle (ASM) hyperplasia is a hallmark of airway remodeling in asthma, which still lacks an effective treatment. Low-density lipoprotein receptor-related protein 1 (LRP1) is involved in regulating the proliferation of various cell types, and the intracellular domain of LRP1 (LRP1-ICD) also exhibits unique biological functions. However, the role of LRP1 in asthma airway remodeling remains unclear. In the present study, LRP1 was increased in ASM cells of mice with OVA-induced chronic asthma, with the elevation in LRP1-ICD protein levels being significantly greater than that of the LRP1 β chain. In vivo experiments demonstrated that inhibiting LRP1 reduced ASM proliferation in these mice. Mechanistically, LRP1 knockdown inhibited the FGF2/ERK signaling pathway, thereby arresting cell cycle progression and suppressing ASM cell proliferation. Additionally, in vitro experiments revealed that the inhibitory effect of LRP1-ICD overexpression on ASM cell proliferation was lost after adjusting the levels of LRP1. LRP1-ICD overexpression inhibited full-length LRP1 protein levels by promoting its protein degradation rather than by suppressing its transcription, thus preventing further exacerbation of asthma. In conclusion, this study clarifies the molecular biological mechanism by which LRP1 regulates ASM proliferation, suggesting targeting full-length LRP1 as a strategy for therapeutic intervention in asthma airway remodeling.

Authors

Ya Deng, Jiaying Zhao, Chen Gong, Wenqian Ding, Lulu Fang, Huaqing Liu, Ming Li, Bing Shen, Shenggang Ding

PAI-1 interaction with sortilin-related receptor 1 is required for lung fibrosis

• Text
• PDF

Abstract

Mutation studies of plasminogen activator inhibitor 1 (PAI-1) have previously implied that PAI-1 promotes lung fibrosis via a vitronectin-dependent (VTN-dependent) mechanism. In the present study, employing 2 distinct murine fibrosis models and VTN-deficient mice, we found that VTN is not required for PAI-1 to drive lung scarring. This result suggested the existence of a profibrotic interaction involving the VTN-binding site on PAI-1 with an unidentified ligand. Using an unbiased proteomic approach, we identified sortilin-related receptor 1 (SorLA) as the most highly enriched PAI-1 binding partner in the fibrosing lung. Investigating the role of SorLA in pulmonary fibrosis demonstrated that deficiency of this protein protected against lung scarring in a murine model. We further found that SorLA is required for PAI-1 to promote scarring in mice, that both SorLA and PAI-1 protein levels are increased in human idiopathic pulmonary fibrosis (IPF) explants, and that these proteins are associated in IPF tissue. Finally, confocal microscopy showed that expression of SorLA in CHO cells increased cellular uptake of PAI-1, and these proteins colocalized in the cytoplasm. Together, these data elucidate a mechanism by which the potent profibrotic mediator PAI-1 drives lung fibrosis and implicate SorLA as a potential therapeutic target in IPF treatment.

Authors

Thomas H. Sisson, John J. Osterholzer, Lisa Leung, Venkatesha Basrur, Alexey Nesvizhskii, Natalya Subbotina, Mark Warnock, Daniel Torrente, Ammara Q. Virk, Sergey S. Gutor, Jeffrey C. Horowitz, Mary Migliorini, Dudley K. Strickland, Kevin K. Kim, Steven K. Huang, Daniel A. Lawrence

G6PC3 promotes genome maintenance and is a candidate mammary tumor suppressor

• Text
• PDF

Abstract

Mutations in genome maintenance factors drive sporadic and hereditary breast cancers. Here, we searched for potential drivers based on germline DNA analysis from a cohort consisting of patients with early-onset breast cancer negative for BRCA1/BRCA2 mutations. This revealed candidate genes that subsequently were subjected to RNA interference–based (RNAi-based) phenotype screens to reveal genome integrity effects. We identified several genes with functional roles in genome maintenance, including Glucose-6-Phosphatase Catalytic Subunit 3 (G6PC3), SMC4, and CCDC108. Notably, G6PC3-deficient cells exhibited increased levels of γH2AX and micronuclei formation, along with defects in homologous recombination (HR) repair. Consistent with these observations, G6PC3 was required for the efficient recruitment of BRCA1 to sites of DNA double-strand breaks (DSBs). RNA-Seq analysis revealed that G6PC3 promotes the expression of multiple homologous recombination repair genes, including BRCA1. Through CRISPR-Select functional-genetic phenotype analysis of G6PC3 germline mutations, we identified 2 germline G6PC3 variants displaying partial loss of function. Furthermore, our study demonstrated that G6pc3 deficiency accelerates mammary tumor formation induced by Trp53 loss in mice. In conclusion, our cohort-based functional analysis has unveiled genome maintenance factors and identified G6PC3 as a potential candidate tumor suppressor in breast cancer.

Authors

Xin Li, Maria Rossing, Ana Moisés da Silva, Muthiah Bose, Thorkell Gudjónsson, Jan Benada, Jayashree Thatte, Jens Vilstrup Johansen, Judit Börcsök, Hanneke van der Gulden, Ji-Ying Song, Renée Menezes, Asma Tajik, Lucía Sena, Zoltan Szallasi, Morten Frödin, Jos Jonkers, Finn Cilius Nielsen, Claus Storgaard Sørensen

The gut microbiome enhances breast cancer immunotherapy following bariatric surgery

• Text
• PDF

Abstract

Bariatric surgery is associated with improved breast cancer (BC) outcomes, including greater immunotherapy effectiveness in a preclinical BC model. A potential mechanism of bariatric surgery–associated protection is the gut microbiota. Here, we demonstrate the dependency of improved immunotherapy response on the post–bariatric surgery gut microbiome via fecal microbiota transplantation (FMT). Response to αPD-1 immunotherapy was significantly improved following FMT from formerly obese bariatric surgery–treated mice. When stool from post–bariatric surgery patients was transplanted into recipient mice and compared to the patients’ presurgery transplants, postsurgery microbes significantly reduced tumor burden and doubled immunotherapy effectiveness. Microbes impact tumor burden through microbially derived metabolites, including branched-chain amino acids (BCAAs). Circulating BCAAs correlated significantly with natural killer T (NKT) cell content in the tumor microenvironment in donor mice after bariatric surgery and FMT recipients of donor cecal content after bariatric surgery compared with obese controls. BCAA supplementation replicated improved αPD-1 effectiveness in 2 BC models, supporting the role of BCAAs in increased immunotherapy effectiveness after bariatric surgery. Ex vivo exposure increased primary NKT cell expression of antitumor cytokines, demonstrating direct activation of NKT cells by BCAAs. Together, the findings suggest that reinvigorating antitumor immunity may depend on bariatric surgery–associated microbially derived metabolites, namely BCAAs.

Authors

Margaret S. Bohm, Sydney C. Joseph, Laura M. Sipe, Minjeong Kim, Cameron T. Leathem, Tahliyah S. Mims, Nathaniel B. Willis, Ubaid A. Tanveer, Joel H. Elasy, Emily W. Grey, Madeline E. Pye, Zeid T. Mustafa, Barbara Anne Harper, Logan G. McGrath, Deidre Daria, Brenda Landvoigt Schmitt, Jelissa A. Myers, Patricia Pantoja Newman, Brandt D. Pence, Marie Van der Merwe, Matthew J. Davis, Joseph F. Pierre, Liza Makowski

LRRC8 channel complexes counterbalance K_ATP channels to mediate swell-secretion coupling in mouse pancreatic β cells

• Text
• PDF

Abstract

Insulin secretion from pancreatic β cells is initiated by membrane potential depolarization, followed by activation of voltage-gated Ca2+ channels to trigger Ca2+-mediated insulin vesicle fusion with the β cell plasma membrane. Here, we show that β cell swelling associated with glucose metabolism was sensed by LRRC8 channel complexes and contributed to insulin secretion. Hypertonic perfusate (360–380 mOsm) dose dependently impaired glucose-stimulated insulin secretion by counteracting β cell swelling. Hypotonic perfusate alone, independent of glucose stimulation or KATP channel closure, was sufficient to increase β cell intracellular Ca2+ and trigger insulin secretion. Inhibition of sodium-potassium-chloride cotransporter-1 with bumetanide, which diminished the intracellular Cl– concentration in β cells and consequently reduced Cl– efflux via LRRC8 channel complexes, also significantly reduced hypotonic-stimulated insulin secretion. Finally, stimulation of insulin secretion by the glucokinase activator GKA50, which is known to induce β cell swelling, was entirely suppressed in β cell–targeted Lrrc8a KO islets. These data support a model wherein the LRRC8 channel complex senses β cell swelling triggered by glucose metabolism and regulates β cell insulin secretion through activation of LRRC8-mediated Cl– efflux.

Authors

Tarek Mohamed Abd El-Aziz, Chen Kang, Litao Xie, John D. Tranter, Sumit Patel, Rahul Chadda, Maria S. Remedi, Rajan Sah

New Pseudomonas infections drive Pf phage transmission in CF airways

• Text
• PDF

Abstract

Pf bacteriophages, lysogenic viruses that infect Pseudomonas aeruginosa (Pa), are implicated in the pathogenesis of chronic Pa infections; phage-infected (Pf+) strains are known to predominate in people with cystic fibrosis (pwCF) who are older and have more severe disease. However, the transmission patterns of Pf underlying the progressive dominance of Pf+ strains are unclear. In particular, it is unknown whether phage transmission commonly occurs horizontally between bacteria via viral particles within the airway or whether Pf+ bacteria are mostly acquired via de novo Pseudomonas infections. Here, we studied Pa genomic sequences from 3 patient cohorts totaling 662 clinical isolates from 105 pwCF. We identified Pf+ isolates and analyzed transmission patterns of Pf within patients between genetically similar groups of bacteria called “clone types.” We found that Pf was predominantly passed down vertically within Pa clone types and rarely via horizontal transfer between clone types within the airway. Conversely, we found extensive evidence of Pa de novo infection by a new, genetically distinct Pf+ Pa. Finally, we observed that clinical isolates showed reduced activity of type IV pili and reduced susceptibility to Pf in vitro. These results cast light on the transmission of virulence-associated phages in the clinical setting.

Authors

Julie D. Pourtois, Naomi L. Haddock, Aditi Gupta, Arya Khosravi, Hunter A. Martinez, Amelia K. Schmidt, Prema S. Prakash, Ronit Jain, Piper Fleming, Tony H. Chang, Carlos Milla, Patrick R. Secor, Giulio A. De Leo, Paul L. Bollyky, Elizabeth B. Burgener

The lectin-like domain of TNF reduces pneumonia-induced injury in the perfused human lung

• Text
• PDF

Abstract

Bacterial pneumonia is the most common cause of acute respiratory distress syndrome (ARDS), characterized by disrupted pulmonary endothelial barrier function, hyperinflammation, and impaired alveolar epithelial fluid clearance. ARDS has a high mortality rate and no proven pharmacological treatments, stressing the need for new targeted therapies. The TIP peptide, mimicking the lectin-like domain of TNF, directly binds to the α subunit of the epithelial Na+ channel, expressed in both alveolar epithelial and capillary endothelial cells, and may increase lung endothelial barrier function and alveolar fluid clearance during bacterial infection. This study tested these potential therapeutic mechanisms of the TIP peptide in a clinically relevant preparation of the ex vivo–perfused human lung injured by Streptococcus pneumoniae. Therapeutic administration of the TIP peptide reduced pulmonary barrier permeability to protein and lung edema formation, increased alveolar edema fluid clearance, and produced an antiinflammatory effect in the airspaces with reductions in IL-6 and IL-8 levels. Additionally, the TIP peptide reduced the translocation of bacteria into the circulation. These findings establish 3 mechanisms of benefit with the TIP peptide to reduce injury in the human lung and support the clinical relevance as a potential therapeutic for pneumococcal bacterial pneumonia.

Authors

Mazharul Maishan, Hiroki Taenaka, Bruno Evrard, Shotaro Matsumoto, Angelika Ringor, Carolyn Leroux, Rudolf Lucas, Michael A. Matthay

The cardiac METTL3/m6A pathway regulates the systemic response to Western diet

• Text
• PDF

Abstract

Regulation of organismal homeostasis in response to nutrient availability is a vital physiological process that involves interorgan communication. The role of the heart in controlling systemic metabolic health is not clear. Adopting a mouse model of diet-induced obesity, we found that the landscape of N6-methyladenosine (m6A) on cardiac mRNA was altered following high-fat/high-carbohydrate feeding (Western diet). m6A is a critical posttranscriptional regulator of gene expression, the formation of which is catalyzed by methyltransferase-like 3 (METTL3). Through parallel unbiased approaches of Nanopore sequencing, mass spectrometry, and protein array, we found regulation of circulating factors under the control of METTL3. Mice with cardiomyocyte-specific deletion of METTL3 showed a systemic inability to respond to nutritional challenge, thereby mitigating the detrimental effects of Western diet. Conversely, increasing cardiac METTL3 level exacerbated diet-induced body weight gain, adiposity, and glucose intolerance. Our findings position the heart at the center of systemic metabolism regulation and highlight an m6A-dependent pathway to be exploited for the battle against obesity.

Authors

Charles Rabolli, Jacob Z. Longenecker, Isabel S. Naarmann-de Vries, Joan Serrano, Jennifer M. Petrosino, George A. Kyriazis, Christoph Dieterich, Federica Accornero

The growth hormone/IGF-1 axis is a risk factor for long-term kidney allograft failure

• Text
• PDF

Abstract

INTRODUCTION Maladaptive hypertrophy, podocyte stress, and depletion contribute to kidney function decline. Although insulin-like growth factor 1 (IGF-1) plays a key role in early hypertrophic responses in the single kidney state, its impact on kidney transplant (KTx) outcomes remains uncertain. This report tests the hypothesis that early IGF-1 exposure reduces KTx survival. METHODS Population datasets compared incident death-censored graft failure (DCGF) rates by age at KTx (n = 366,404) with IGF-1 levels by age (n = 15,014). A clinical study of 216 KTx recipients evaluated the association of IGF-1 exposure with DCGF and secondary outcomes of proteinuria and biopsy-proven acute rejection. IGF-1 exposure was modeled using pre-KTx IGF-1 levels and donor kidney dose estimated from the donor/recipient body surface area ratio reflecting allograft hyperfiltration. The association of DCGF with an IGF1 SNP linked to high IGF-1 levels was assessed in 724 genotyped allograft recipients. Single-cell transcriptomic data from first-year post-KTx patients and binephric donors were compared to assess intrarenal cellular expression of IGF1, IGF1R, and growth hormone receptor (GHR) transcripts. RESULTS DCGF risk by age at KTx paralleled IGF-1 levels by age. Higher IGF-1 exposure was associated with significantly increased risks of DCGF, proteinuria, and T cell–mediated rejection. Genotypic analysis showed a 50% increase in DCGF risk per risk allele at IGF1 expression quantitative trait locus rs35767. First-year biopsy results revealed no increase in intrarenal IGF1 transcripts, while GHR and IGF1R transcripts were suppressed, consistent with circulating IGF-1 (vs. graft-derived IGF-1) being the primary source of IGF-1 exposure. CONCLUSION We identify a role for the growth hormone/IGF-1 axis in reducing KTx survival.

Authors

Matthew Cusick, Viji Nair, Damian Fermin, John Hartman, Jeffrey A. Beamish, Zeguo Sun, Zhongyang Zhang, Edgar Otto, Rajasree Menon, Sudha Nadimidla, Nicholas Demchuk, Kelly Shaffer, Peter Heeger, Weija Zhang, Madhav C. Menon, Matthias Kretzler, Roger C. Wiggins, Abhijit S. Naik

Neonatal diabetes–associated missense PDX1 variant disrupts chromatin association and protein-protein interaction

• Text
• PDF

Abstract

PDX1 mutations are associated with multiple forms of diabetes, including syndromic, neonatal, mature onset diabetes of the young (MODY), and type 2 diabetes. Two PDX1 missense mutations (Thr151Met and Asn196Thr) were identified in a pediatric female patient that cause permanent neonatal diabetes, pancreas hypoplasia, and a malformed gallbladder. We found that the mouse Pdx1 Asn197Thr variant (homologous to human PDX1 Asn196Thr), but not Pdx1 Thr152Met (homologous to human PDX1 Thr151Met), altered its nuclear localization and disrupted the PDX1-ONECUT1 interaction. Neither variant substantially affected PDX1 protein stability, but both reduced PDX1 binding to the Pdx1 gene promoter. Importantly, the Pdx1 Asn197Thr variant caused pancreas agenesis and reduced enteroendocrine cells in the duodenum in genetically engineered mice, due at least in part to reduced Pdx1 promoter binding and disrupted PDX1-ONECUT1 interaction.

Authors

Xiaodun Yang, Angela Zanfardino, Riccardo Schiaffini, Jeff Ishibashi, Bareket Daniel, Matthew W. Haemmerle, Novella Rapini, Alessia Piscopo, Emanuele Miraglia del Giudice, Maria Cristina Digilio, Raffaele Iorio, Mafalda Mucciolo, Stefano Cianfarani, Dario Iafusco, Fabrizio Barbetti, Doris A. Stoffers

De novo variant in RING finger protein 213 causes systemic vasculopathy

• Text
• PDF

Abstract

Systemic arterial stenosis, including moyamoya disease (MMD) and middle aortic syndrome (MAS), is a rare condition of unclear etiology. MMD is a cerebral angiopathy, and MAS affects the abdominal and thoracic aorta. Although some genetic associations with MAS have been identified, the causes remain elusive. In this study, de novo heterozygous missense variants of RING finger protein 213 (RNF213) (p.His4058Pro and p.Thr4155Pro) in 2 unrelated families with MAS and MMD were studied by whole-exome sequencing. To elucidate the significance of these variants, we produced knockin mice carrying the Rnf213 p.His4058Pro variant. Homozygous knockin mice exhibited perinatal lethality because of respiratory failure and lung dysplasia, suggesting that this variant is pathogenic. Lung dysplasia in homozygous knockin mice was associated with upregulated innate immunity and inflammatory responses and downregulated cell proliferation. These findings suggested that in mice, the RNF213 p.His4058Pro variant plays critical roles in regulation of innate immunity and inflammation that affect lung development, revealing the complexity of RNF213 function in various tissues and species. In conclusion, this study provides insights into the genetic basis of MAS and MMD, highlights the potential involvement of RNF213 variants in systemic vasculopathy, and identifies unexpected associations with lung development and immune processes.

Authors

Ayako Kashimada, Tomoko Mizuno, Eriko Tanaka, Susumu Hosokawa, Tomohiro Udagawa, Yuichi Hiraoka, Keisuke Uchida, Tomohiro Morio, Kenjiro Kosaki, Masatoshi Takagi

Annual PM_2.5 exposure and clinical, laboratory, and stroke-risk outcomes in pediatric sickle cell disease

• Text
• PDF

Abstract

Sickle cell disease (SCD) causes severe morbidity and early mortality, yet it varies phenotypically. Both air pollution and SCD affect the cardiorespiratory, inflammatory, and endothelial systems; however, limited evidence exists on the effect of long-term air pollution exposure in SCD. We hypothesized that annual ambient (outdoor) concentrations of fine particulate matter (PM2.5), particles with a diameter of 2.5 μm or less, at a child’s home would be significantly associated with worse clinical, laboratory, and stroke-risk imaging outcomes. Patient data for this retrospective study were obtained from a cohort of children with SCD (from 2010 to 2019). Annual PM2.5 exposure was estimated using remote-sensing air pollution datasets. Statistical analyses employed fixed effects multivariable models, offering a robust approach to isolate the effect of PM2.5 exposure. The final cohort included 1,089 children with SCD. Higher annual PM2.5 concentrations were significantly associated with more annual hospital days, higher likelihood of hospitalization and abnormal stroke-risk screening, and elevated inflammatory markers. Of note, hydroxyurea use mitigated the inflammatory response to PM2.5 but did not mitigate the effect of PM2.5 on clinical outcomes. Importantly, the elevated stroke risk associated with PM2.5 exposure persisted, even among children receiving hydroxyurea therapy, highlighting a critical concern in pediatric SCD management. These results underscore the clinical importance of addressing environmental factors for comprehensive SCD care.

Authors

Paul E. George, Grace Kalmus, Joseph Lipscomb, David H. Howard, Benjamin Kopp, Wilbur A. Lam, Stefanie Ebelt

Remdesivir postexposure prophylaxis limits measles-induced “immune amnesia” and measles antibody responses in macaques

• Text
• PDF

Abstract

Measles remains one of the most important causes of worldwide morbidity and mortality in children. Measles virus (MeV) replicates extensively in lymphoid tissue, and most deaths are due to other infectious diseases associated with MeV-induced loss of circulating antibodies to other pathogens. To determine whether remdesivir, a broad-spectrum direct-acting antiviral, affects MeV-induced loss of antibody to other pathogens, we expanded the VirScan technology to detect antibodies to both human and macaque pathogens. We measured the antibody reactivity to MeV and non-MeV viral peptides using plasma from MeV-infected macaques that received remdesivir either as postexposure prophylaxis (PEP) (d3–d14) or as late treatment (LT) (d11–d22) in comparison with macaques that were not treated. Remdesivir PEP, but not LT, limited the loss of antibody to non-MeV pathogens. Remdesivir PEP also limited the antibody response to MeV with a decrease in both the magnitude and breadth of the epitopes recognized. LT had little effect on the magnitude of the MeV-specific antibody response but affected the breadth of the response. Therefore, early, but not late, treatment of measles with the direct-acting antiviral remdesivir prevents the loss of antibody to other pathogens but decreases the response to MeV.

Authors

Andy Kwan Pui Chan, Liting Liu, William R. Morgenlander, Manjusha Thakar, Nadine A. Peart Akindele, Jacqueline Brockhurst, Shristi Ghimire, Maggie L. Bartlett, Kelly A. Metcalf Pate, Victor C. Chu, Meghan S. Vermillion, Danielle P. Porter, Tomas Cihlar, Michael J. Mina, H. Benjamin Larman, Diane E. Griffin

Interaction between native and prosthetic visual responses in optogenetic visual restoration

• Text
• PDF

Abstract

Degenerative retinal disorders leading to irreversible photoreceptor death are a common cause of blindness. Optogenetic gene therapy aims to restore vision in affected individuals by introducing light-sensitive opsins into the surviving neurons of the inner retina. While up until now, the main focus of optogenetic therapy has been on terminally blind individuals, treating at stages where residual native vision is present could have several advantages. However, it is still unknown how residual native and optogenetic vision would interact if present at the same time. Using transgenic mice expressing the optogenetic tool ReaChR in ON-bipolar cells, we herein examine this interaction through electroretinography (ERG) and visually evoked potentials (VEP). We find that optogenetic responses show a peculiar ERG signature and are enhanced in retinas without photoreceptor loss. Conversely, native responses are dampened in the presence of ReaChR. Moreover, in VEP recordings, we find that optogenetic responses reach the cortex asynchronous to the native response. These findings should be taken into consideration when planning future clinical trials and may direct future preclinical research to optimize optogenetic approaches for visual restoration. The identified ERG signatures, moreover, may serve to track treatment efficiency in clinical trials.

Authors

Eleonora Carpentiero, Steven Hughes, Jessica Rodgers, Nermina Xhaferri, Sumit Biswas, Michael J. Gilhooley, Mark W. Hankins, Moritz Lindner

Lactate programs PBX1 lactylation and mesangial proliferation in lupus nephritis

• Text
• PDF

Abstract

Lupus nephritis (LN) constitutes the most common organ-threatening manifestation of systemic lupus erythematosus (SLE), with the pathological proliferation of mesangial cells (MCs) recognized as a critical factor in its pathogenesis and progression. Self-DNA-containing immune complex (DNA-IC) represents a prime pathogenic factor in SLE, yet its pathological effect on MCs remains unclear. In the present study, we elucidated the mechanism underlying the excessive proliferation of MCs following the recognition of DNA-IC in patients with LN. Here, we pinpointed that the excessive proliferation of MCs was attributed to an anomalous transition from the G1 to the S phase of the cell cycle in patients with LN. Mechanically, the dysfunction of P27 protein resulted in the aberrant G1-S phase transition, and the phenomenon was closely related to the ubiquitin-mediated degradation of its key transcription factor, PBX1. This degradation was regulated by lactylation of PBX1 in the site of Lys40 residue. The elevated lactylation level of PBX1 protein was caused by the upregulation of glycolysis levels induced by DNA-IC. Accordingly, targeting lactate production in MCs from patients with LN effectively alleviated their renal inflammation and fibrosis progression. Elevated lactate resulted in PBX1 lactylation, leading to excessive proliferation of MCs and, thus, serving as a promising therapeutic target for LN.

Authors

Enzhuo Liu, Chenghua Weng, Chenchu Yan, Xingchen Zhu, Xinyue Li, Mengdi Liu, Zhenke Wen, Zhichun Liu

Single-cell transcriptional analysis reveals allergen-specific signatures in human γδ T cells

• Text
• PDF

Abstract

The role of gamma-delta T (γδ T) cells in immune responses to common allergens is poorly understood. Here, we utilized single-cell (sc) transcriptomic analysis of allergen-reactive γδ T cells in humans to characterize the transcriptional landscapes and TCR repertoires in response to cockroach (CR) and mouse (MO) allergens. Using a potentially novel activation-induced marker (AIM) assay that allows detection of γδ T cells combined with scRNA sequencing and TCR repertoire analysis, we identified both shared and allergen-specific γδ T cell activation patterns and gene expression profiles. While CR extract activated both Vδ1 and Vδ2 subsets, MO extract primarily stimulated Vδ2 cells. Our analysis revealed allergen-specific clusters with distinct functional signatures, including enhanced inflammatory responses and cytotoxic effector functions in MO-specific γδ T cells and natural killer cell–mediated immunity and IFN-γ signaling in CR-specific populations. Comparison of allergic and nonallergic individuals highlighted differences in gene expression and TCR repertoires, including a higher IFNG expression in the CR-allergic compared with nonallergic cohorts, suggesting that phenotypic and functional differences are associated with γδ T allergen responses. This study provides insights into the cellular and molecular heterogeneity and functionality of allergen-reactive γδ T cells, offering a foundation for understanding their role in allergic diseases and potential therapeutic interventions.

Authors

Kendall Kearns, Sloan A. Lewis, Esther Dawen Yu, Adam Abawi, Eric Wang, Synaida Maiche, Monalisa Mondal, Pandurangan Vijayanand, Grégory Seumois, Bjoern Peters, Alessandro Sette, Ricardo Da Silva Antunes