Cell biology
Abstract
B cells contribute to the pathogenesis of food allergies as they induce allergen-specific antibody production. Clinically-used allergen-specific immunotherapies have shown to induce regulatory B cell (Bregs) subsets as well as target and reduce allergy-driving B cell functions. This report aims to elucidate the contribution of regulatory B cells to an allergen-encapsulating nanoparticle (aeNP) immunotherapy in a murine model of food allergy. In this model, B cells directly associated with aeNPs. CD20+ B cell depletion after aeNP treatment increased the number of mice with severe allergic reactions during oral food challenges and reduced the expansion of regulatory immune cells including CD103+ dendritic cells (DCs) and CCR9+ gut-homing regulatory T cells, indicating that B cells are a component of aeNP immunomodulation. B cell communication in the gastrointestinal tract of aeNP-treated mice identified CD23 signaling as a potential inducer of regulatory CD103+ DC functions and disrupter of allergy-driving B cell-T cell communication. These tolerogenic signaling patterns were also identified in IL-10+ B cells, which have been known to impart regulatory immune effects in both murine and human disease. Ultimately, B cells are a component of the complex immunomodulation leading to aeNP efficacy at reducing allergic reactivity.
Authors
Laila M. Rad, Michael N. Saunders, Laura A. Williams, Katarzyna W. Janczak, Chris L. Dorsett, Kate V. Griffin, Elizabeth J. Bealer, Jeffrey A. Ma, Sayre A. Tillery, Jyotirmoy Roy, Stephen D. Miller, Jessica J. O'Konek, Lonnie D. Shea
Abstract
YAP/TAZ signaling is required for initiation of lung alveolar repair, yet previous studies in idiopathic pulmonary fibrosis (IPF) predicted increased YAP/TAZ signaling in alveolar epithelial cells (AECs). We investigated whether persistent YAP/TAZ AEC signaling contributes to failed epithelial repair and persistent fibrotic remodeling. In IPF lungs, we identified increased YAP+/TAZ+ AECs and increased transcriptional target expression. Pharmacological YAP/TAZ activation in human AEC organoids and in murine AT2 cell organoids generated with genetic YAP/TAZ activation (YTactive) (via deletion of Hippo-kinases Stk3/4), resulted in phenotype shifts into aberrant transitional and airway-like states. Bleomycin injury of YTactive mice resulted in persistent fibrotic remodeling at 28- and 56-days post-bleomycin injury. Gene promoter activity associated with transitional cell markers (Krt19, Hopx, and Runx2) was increased in YTactive AT2 cells. Immunofluorescent staining showed a loss of AT2 associated Cebpa and increased Krt19 in YTactive lineage traced AT2 cells 28 days post-injury. Inhibition of YAP/TAZ using Verteporfin resulted in improved lung repair in YTactive mouse lungs, including restored Cebpa and decreased Krt19+ transitional cells. These findings demonstrate sustained YAP/TAZ activation drives abnormal alveolar repair and persistent fibrotic remodeling. Blocking aberrant persistent YAP/TAZ activity promotes adaptive repair and has potential as a therapeutic strategy for pulmonary fibrosis.
Authors
Isabella P. Gaona, A. Scott McCall, Natalie M. Geis, Arlo C. Colvard, Gianluca T. DiGiovanni, Taylor P. Sherrill, Ujjal K. Singha, David S. Nichols, Ana P. Serezani, Holly E. David, Jean-Philippe Cartailler, Shristi Shrestha, Sergey S. Gutor, Timothy S. Blackwell, Jonathan A. Kropski, Jason J. Gokey
Abstract
Human CD4+ T cells utilize nutrients, including lipids, to support their activation and polarization. Considering the pivotal role of lipoproteins in lipid transport, we reasoned that lipoprotein uptake and processing could effect CD4+ T cell function. Here, we demonstrate that activation of human CD4+ T cells induced expression of LDL receptor (LDLR) to facilitate LDLR-mediated endocytosis of LDL. Degradation of surface LDLR on CD4+ T cells with PCSK9 hampered activation and proliferation of the cells. Lipoprotein deprivation or blocking of lysosomal cholesterol egress impaired activation of mechanistic target of rapamycin complex 1 (mTORC1), affecting CD4+ T cell activation and proliferation. Furthermore, lipoprotein deprivation of cultured primary CD4+ T cells lead to reduced expression of c-MAF and FOXP3, key transcription factors for IL-10, accompanied by reduced IL-10 secretion. The pivotal role of LDLR-mediated lipoprotein uptake for mTORC1 activity, c-MAF and FOXP3 expression, and IL-10 secretion was confirmed using LDLR-dysfunctional CD4+ T cells from patients with homozygous familial hypercholesterolemia. Our study offers valuable insights into the lipoprotein metabolism of human CD4+ T cells and their reliance on the LDLR pathway for activation and polarization, a feature that may be leveraged to modulate CD4+ T cell function.
Authors
Angela Markovska, Niels S. van Heusden, Dagmar Duijzer, Alejandra Bodelón, Greta Rogani, Enric Mocholi, Edwin C.A. Stigter, Can Gulersonmez, Sander Kooijman, Leonie Van der Zee, Monique T. Mulder, Jeanine E. Roeters van Lennep, Patrick C.N. Rensen, Jorg van Loosdregt, Sebastiaan J. Vastert, Noam Zelcer, Marianne Boes, Henk S. Schipper
Abstract
Tumor cells are constantly confronted with nutrient deprivation; however, the effect of serum starvation on the remodeling of endosomal compartments and extracellular vesicles (EVs) in tumor cells remains unclear. Here, we found that serum starvation pronouncedly promotes multivesicular body (MVB) biogenesis, EV formation, and cargo selection. Specifically, by generating a constitutively active Rab5Q79L mutant to induce the enlargement of MVB, we revealed for the first time to our knowledge that ANXA3 is sorted into intraluminal vesicles (ILVs) of MVB. Mechanistically, we confirmed that serum starvation regulates the endosomal sorting complex required for transport–associated (ESCRT-associated) protein ALG-2 interacting protein X (ALIX), which recruits ESCRT-III to MVB and binds to annexin A3 (ANXA3) to mediate its sorting into ILVs of MVB. Our study highlights that serum starvation promotes an ALIX-dependent ESCRT-III recruitment pathway, which loads protumor ANXA3 cargo to exert a profound effect on tumor progression.
Authors
Xueqiang Peng, Jiaxing Liu, Guolong Zeng, Yafei Xiao, Zhixiong Hao, Guangpeng He, Hongyuan Jin, Yu Gao, Shilei Tang, Shibo Wei, Yan Li, Yifan Yu, Liang Yang, Hangyu Li
Abstract
Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related mortality worldwide, yet its molecular drivers are not fully defined. Emerging evidence highlights the importance of tumor-stroma interactions mediated by secreted glycoproteins. However, the mechanisms by which cancer cells regulate the secretion of these protumorigenic proteins remain largely unknown. Endoplasmic reticulum–resident (ER-resident) N-glycan–processing enzymes regulate proper protein folding, a prerequisite for glycoproteins to exit the ER and undergo secretion. By evaluating their prognostic significance in lung tumors and conducting functional screening in lung cancer cells, we identify α-glucosidase II (α-Glc II) as a key regulator of NSCLC progression. α-Glc II promotes tumor growth and dissemination in a glucosidase activity–dependent manner in orthotopic mouse lung tumor model. Genetic disruption of α-Glc II induced ER stress and reduced cell proliferation and motility. Mechanistically, α-Glc II–mediated N-glycan modification regulated the ER-to-Golgi trafficking and secretion of specific oncogenic glycoproteins, including lysyl hydroxylase 2 (LH2), Tissue Inhibitor of Metalloproteinase 1 (TIMP1), and TGF-β, which are known to be associated with extracellular matrix remodeling. These findings uncover a role for ER glycosylation machinery in shaping the NSCLC secretome and highlight α-Glc II as a potential therapeutic target.
Authors
Shike Wang, Na Ding, Angelo Chen, Derrick Cardin, Yuting Xu, Kate Grimley, William K. Russell, Jun Xu, Jonathan M. Kurie, Guan-Yu Xiao, Xiaochao Tan
Abstract
Tuberous sclerosis complex (TSC) and Lymphangioleiomyomatosis (LAM) lack well-defined cellular origins, limiting treatment options. In this report, scRNA-seq of Tsc2+/− mouse renal cystadenomas revealed an 80-fold increase in a tumor cell subpopulation with neural crest features, and expressing known cranial neural crest genes as SRY box transcription factor 9 (Sox9), transcription factor activator protein (Tfap2a), and candidate neurocristopathy markers, osteopontin (Spp1), lipocalin-2 (Lcn2), clusterin (Clu), and cytokeratin 18 (Krt18). These signatures were validated in mouse tumors, and LAM patient lesions and serum, identifying a tumor phenotype distinct from traditional VEGFD detection. Pathway analysis indicated activation of WNT/SHH signaling, nephric duct formation, and pro-tumorigenic signals, with transcription factor 7 (Tcf7) and ephrin-A ligands as key upstream regulators. Spp1 KO in cranial neural crest cells (CNCCs) significantly reduced proliferation (28–33%), migration (54-76%), and invasion (29-64%) without affecting viability, while Tsc2 KO increased viability 3 to 6-fold with minimal impact on chemotaxis. Elevated serum levels of SPP1 and KRT18 in some LAM patients, decreased LCN2 in nearly all, and distinct increases in VEGFD suggest complementary roles for these biomarkers. Overall, findings support a neurocristopathic model of tumor development in TSC and LAM and identify potential biomarkers and therapeutic targets beyond mTOR inhibition.
Authors
Uchenna J. Unachukwu, Enio B. Garcia, Nooralam Rai, Jeanine M. D'Armiento
Abstract
Hyperglycemia is a principal driver of β cell failure and multiple-organ complications in diabetes. Chronic exposure to hyperglycemia overstimulates mTORC1, disrupting glucose metabolism and promoting ER stress, oxidative stress, and inflammation; however, the upstream metabolic signal(s) linking glucose to mTORC1 activation remains unclear. Here, we identified glucosamine as a key metabolite connecting elevated glucose to mTORC1 signaling in pancreatic islets and kidney, both major targets of hyperglycemic damage. Using 13C6-glucose metabolic labeling in diabetic rodents treated with or without the SGLT2 inhibitor dapagliflozin or insulin, combined with targeted metabolomics and metabolic flux analysis, we found that tissue glucose concentrations strongly correlated with glucosamine. A similar correlation with plasma glucose was conserved in humans with or without type 2 diabetes, and inversely associated with β cell function. In vitro, low-dose glucosamine stimulated mTORC1 in islets and kidney proximal tubule cells in an O-GlcNAcylation–dependent manner. Broad phosphoproteomics and transcriptomics analyses in β cells showed that glucosamine activated mTORC1-regulating pathways, induced oxidative stress, ER stress, and dedifferentiation. Genetic inhibition of β cell mTORC1 via heterozygous Raptor knockout, as well as pharmacologic inhibition of the glucosamine/mTORC1 axis through SGLT2 inhibition, alleviated β cell stress, improved glycemic control, and restored β cell function. These findings identified the glucosamine/mTORC1 pathway as an important mediator of β cell and kidney dysfunction in diabetes.
Authors
Yael Riahi, Aviram Kogot-Levin, Ziv Teselpapa, Elisheva Zemelman, Fatema Gamal, Tamar Cohen, Abed Nasereddin, Idit Shiff, Ifat Abramovich, Bella Agranovich, Dana Avrahami, Liad Hinden, Erol Cerasi, Daljeet Kaur, Lihi Grinberg, Ron Piran, Joseph Tam, Ernesto Bernal-Mizrachi, Erez Dror, Gil Leibowitz
Abstract
Biallelic loss-of-function variants in the adaptor protein complex 4 (AP-4) disrupt trafficking of transmembrane proteins at the trans-Golgi network, including the autophagy-related protein 9A (ATG9A), leading to childhood-onset hereditary spastic paraplegia (AP-4-HSP). AP-4-HSP is characterized by features of both a neurodevelopmental and degenerative neurological disease. To investigate the molecular mechanisms underlying AP-4-HSP and identify potential therapeutic targets, we conducted an arrayed CRISPR/Cas9 loss-of-function screen of 8,478 genes, targeting the ‘druggable genome’, in a human neuronal model of AP-4 deficiency. Through this phenotypic screen and subsequent experiments, key modulators of ATG9A trafficking were identified, and complementary pathway analyses provided insights into the regulatory landscape of ATG9A transport. Knockdown of ANPEP and NPM1 enhanced ATG9A availability outside the trans-Golgi network, suggesting they regulate ATG9A localization. These findings deepen our understanding of ATG9A trafficking in the context of AP-4 deficiency and offer a framework for the development of targeted interventions for AP-4-HSP.
Authors
Marvin Ziegler, Cedric Günter, Julian E. Alecu, Xutong Xue, Hyo-Min Kim, Afshin Saffari, Alexandra K. Davies, Mustafa Sahin, Darius Ebrahimi-Fakhari
Abstract
Idiopathic pulmonary fibrosis (IPF) is characterized by parenchymal scarring reflecting an imbalance between collagen deposition by myofibroblasts (MFs) and its turnover. Although collagen clearance is essential for fibrosis resolution, this process and its potential for therapeutic modulation in IPF are poorly understood. Here we evaluated internalization of degraded collagen and the role of its requisite endocytic receptor mannose receptor C-type 2 (MRC2), in lung tissue and MFs from IPF patients and bleomycin-injured mice. Fibrotic human and murine lung tissue exhibited an accumulation of degraded collagen, highlighting a failure of its clearance. MFs from fibrotic lung demonstrated a reduced capacity to internalize extracellular degraded collagen, with a concomitant reduction in MRC2 expression and endolysosomal activity. Both diminished collagen uptake and MRC2 expression recovered to baseline levels during spontaneous resolution of bleomycin fibrosis. In vitro treatment of IPF or TGF-β-elicited MFs with a variety of mechanistically distinct agents known to effect phenotypic dedifferentiation restored defective collagen internalization. Although enhanced uptake was MRC2-dependent, it involved increased endolysosomal activity rather than increased MRC2 expression. These results implicate defective MRC2-dependent collagen internalization and endolysosomal function in MFs as important factors contributing to fibrosis that may be therapeutically targeted to promote resolution.
Authors
Natalie M. Walker, Sean M. Fortier, Jennifer Speth, Steven K. Huang, Sergey Gutor, Timothy S. Blackwell, Marc Peters-Golden
Abstract
Ubiquitin-Specific Protease 18 (USP18) is a deISGylation enzyme and antineoplastic target. To develop USP18 inhibitors, an enzymatically active human recombinant USP18 protein was engineered suitable for high-throughput screening of ~80,000 chemical compounds. Three of them substantially inhibited USP18 enzymatic activity with β-lapachone having prominent antineoplastic activity. Independent β-lapachone treatments of murine and human lung cancer cell lines statistically-significantly reduced proliferation and increased apoptosis. Gain of USP18 expression antagonized these effects. β-lapachone treatments statistically-significantly repressed lung cancer xenograft growth. β-lapachone increased reactive oxygen species (ROS), but antineoplastic effects occurred at dosages with negligible ROS production. ROS scavenger treatments did not rescue β-lapachone effects at these concentrations, consistent with an ROS-independent mechanism. Interferon-Stimulated Response Element (ISRE) reporter assays following β-lapachone treatment activated this reporter. USP18 co-transfection antagonized this activity. β-lapachone treatments increased global ISGylation. RNA sequencing of lung cancer cells engineered with or without enhanced USP18 expression showed specific pathways affected by β-lapachone treatment. Proteomic analysis of these treated cells revealed known and new ISGylated proteins. In silico modeling identified a unique USP18 pocket where these USP18 inhibitors bind. Engineered mutation of this pocket disrupted β-lapachone activity. Taken together, β-lapachone is an antineoplastic tool compound useful for USP18 inhibitor development.
Authors
Blessing O. Ogunlade, Kevin N. Dalby, Samuel C. Okpechi, Eun Jeong Cho, Liliya Tyutyunyk-Massey, Zibo Chen, Xiuxia Liu, Joseph Ivanic, Brian Luke, Shyamal D. Desai, Yair Alfaro, Ashwini K. Devkota, Rae M. Sammons, Gilbert G. Privé, Xi Liu, Ethan Dmitrovsky
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