Research Article
Abstract
Myelodysplastic syndromes (MDSs) are malignant hematopoietic stem and progenitor cell (HSPC) disorders that lead to ineffective blood production with poor outcomes. We previously showed that F-box only protein 11 (FBXO11) is downregulated in MDS, and here we report how this event contributes to disease progression. Integration of multiomics data revealed that the SCF-FBXO11 complex regulates spliceosome and ribosome components in a nucleophosmin 1 (NPM1)-centric network. FBXO11 facilitates the ubiquitylation of NPM1, whereby deletion of FBXO11 results in the reorganization of NPM1 and a de-repression of alternative splicing. Label-free total quantitative proteomics demonstrated that the FBXO11-NPM1 interactome was markedly downregulated in cells from patients with CD34+ MDS. In addition, we discovered that MYC was evicted from the FBXO11 promoter by TLR2 activation, revealing that it was a MYC target gene and explaining why FBXO11 expression was decreased in MDS. In MDS mouse models, genetic ablation of Fbxo11 exacerbated neutropenia concomitant with a profound decrease in NPM1 protein levels. Finally, we discovered rare mutations in FBXO11, which mapped to a previously unstudied functional intrinsically disordered region (IDR) in the N-terminus responsible for binding NPM1. These data support a model in which FBXO11 rewires RNA binding and ribosomal subnetworks through ubiquitylation of NPM1, ultimately restricting MDS progression.
Authors
Madeline Niederkorn, Lavanya Bezavada, Anitria Cotton, Lance E. Palmer, Lahiri Konada, Trent Hall, Vishwajeeth R. Pagala, Jinbin Zhai, Zuo-Fei Yuan, Yingxue Fu, Jacob A. Steele, Shilpa Narina, Andrew Schild, Chengzhou Wu, Sarah Aminov, Michael Schieber, Erin McGovern, Aaron B. Taylor, Sandeep Gurbuxani, Peng Xu, Peng Ji, Laura J. Janke, Anthony A. High, Guolian Kang, Shondra M. Pruett-Miller, Mitchell Weiss, Amit Verma, Raajit K. Rampal, John D. Crispino
Abstract
Despite overexpression of N-acetyltransferase 10 (NAT10) in colorectal cancer (CRC), its immunomodulatory role in the tumor microenvironment remains elusive. Here, we reveal that NAT10 promotes immune evasion through N4-acetylcytosine–dependent (ac4C-dependent) mRNA stabilization. Using syngeneic mouse models (MC38/CT-26), intestinal epithelial-cell specific Nat10 conditional KO (Nat10cKO) mice, patient-derived organoids, and clinical specimens, we show that Nat10 ablation enhanced CD8+ T cell–mediated antitumor immunity. Single-cell RNA-seq revealed increased cytotoxic CD8+ T cell infiltration in Nat10cKO tumors, which was corroborated by the inverse correlation of tumoral NAT10 expression and CD8+ T cell number in clinical specimens. Multi-omics integration analysis identified DKK2 as the predominant NAT10-regulated transcript. NAT10 stabilized DKK2 mRNA via ac4C modification, leading to high expression of the DKK2 protein. Secreted DKK2 engaged LRP6 receptors to activate AKT-mTOR signaling, inducing cholesterol accumulation in CD8+ T cells and impairing their cytotoxicity. Pharmacological NAT10 inhibition (Remodelin treatment) or DKK2 neutralization restored CD8+ T cell function and synergized with anti–PD-1 therapy. Our findings establish the NAT10/DKK2/LRP6/AKT-mTOR/cholesterol axis as a critical regulator of CD8+ T cell dysfunction in CRC, positioning NAT10/DKK2 as a potential target to enhance immunotherapy efficacy.
Authors
Mengmeng Li, Xiaoya Zhao, Jun Wu, Shimeng Zhou, Yao Fu, Chen Chen, Zhuang Ma, Jiawen Xu, Yun Qian, Zhangding Wang, Bo Wang, Qiang Wang, Qingqing Ding, Changyu Chen, Honggang Wang, Xiaozhong Yang, Weijie Dai, Wenjie Zhang, Shouyu Wang
Abstract
Protectin DX (PDX) is a member of the superfamily of specialized proresolving mediators and exerts anti-inflammatory actions in animal models; however, its signaling mechanism remains unclear. Here, we demonstrate the analgesic actions of PDX in a mouse model of tibial fracture–induced postoperative pain (fPOP). Intravenous early- and late-phase treatment of PDX (100 ng/mouse) effectively alleviated fPOP. Compared with protectin D1 (PD1)/neuroprotectin D1, DHA, steroids, and meloxicam, PDX provided superior pain relief. While dexamethasone and meloxicam prolonged fPOP, PDX shortened the pain duration. The analgesic effects of PDX were abrogated in Gpr37−/− mice, which displayed deficits in fPOP resolution. PDX was shown to bind GPR37 and induce calcium responses in peritoneal macrophages. LC-MS/MS–based lipidomic analysis revealed that endogenous PDX levels were approximately 10-fold higher than those of PD1 in muscle at the fracture site. PDX promoted macrophage polarization via GPR37-dependent phagocytosis and efferocytosis through calcium signaling in vitro, and it further enhanced macrophage viability and efferocytosis in vivo via GPR37. Finally, PDX rapidly modulated nociceptor neuron responses by suppressing C-fiber–induced muscle reflex in vivo and calcium responses in DRG neurons ex vivo and by reducing TRPA1/TRPV1-induced acute pain and neurogenic inflammation in vivo. Our findings highlight multiple benefits of PDX to manage postoperative pain and promote perioperative recovery.
Authors
Yize Li, Sangsu Bang, Jasmine Ji, Jing Xu, Min Lee, Sharat Chandra, Charles N. Serhan, Ru-Rong Ji
Abstract
Mutation-associated neoantigens (MANAs) are highly cancer-specific targets for immunotherapy where peptides derived from intracellular mutant proteins are presented on the cell surface via HLA molecules. T cell–engaging bispecific antibodies and CAR T cells can target MANAs to eliminate cancer cells via T cell activation. However, the low antigen density of MANAs on the cell surface can limit therapeutic efficacy. Here, we investigated whether increasing the affinity of the H2 single-chain variable fragment (scFv) targeting the p53 R175H MANA (HMTEVVRHC presented on HLA-A*02:01) improves its therapeutic effect. We identified higher-affinity H2 variants via phage biopanning and a thiocyanate elution method. Increasing bispecific antibody affinity to the low nanomolar range increased cancer cell killing and tumor control in mouse xenograft models without sacrificing antigen specificity. We next asked how increasing scFv affinity impacts CAR T cell function — a matter of debate. We appended each variant scFv to a CD28z CAR, CD3γ, or the T cell receptor. In striking contrast to the bispecific antibody results, increasing CAR affinity decreased function in each CAR format due to lower T cell activation upon interaction with target cancer cells. These results have important implications for the design of future immunotherapeutic approaches targeting low-density antigens.
Authors
Sarah R. DiNapoli, Katharine M. Wright, Brian J. Mog, Alexander H. Pearlman, Tushar D. Nichakawade, Nikita Marcou, Emily Han-Chung Hsiue, Michael S. Hwang, Jacqueline Douglass, Qiang Liu, Evangeline Watson, Marco Dal Molin, Joshua D. Cohen, Maria Popoli, Suman Paul, Maximilian F. Konig, Nicolas Wyhs, P. Aitana Azurmendi, Stephanie Glavaris, Jiaxin Ge, Tolulope O. Awosika, Jin Liu, Kathleen L. Gabrielson, Sandra B. Gabelli, Drew M. Pardoll, Chetan Bettegowda, Nickolas Papadopoulos, Kenneth W. Kinzler, Shibin Zhou, Bert Vogelstein
Abstract
Chimeric antigen receptor T cell (CAR-T) therapy has led to significant improvements in patient survival. However, a subset of patients experience high-grade toxicities, including cytokine release syndrome (CRS) and immune cell–associated hematological toxicity (ICAHT). We utilized IL-2Ra knockout mice to model toxicities with elevated levels of IL-6, IFN-γ, and TNF-α and increased M1-like macrophages. Onset of CRS was accompanied by a reduction in peripheral blood neutrophils due to disruption of bone marrow neutrophil homeostasis characterized by an increase in apoptotic neutrophils and a decrease in proliferative and mature neutrophils. Both nontumor-bearing and Em-ALL tumor-bearing mice recapitulated the cooccurrence of CRS and neutropenia. IFN-γ–blockade alleviated CRS and neutropenia without affecting CAR-T efficacy. Mechanistically, a Th1-Th17 imbalance was observed to drive cooccurrence of CRS and neutropenia in an IFN-γ–dependent manner leading to decreased IL-17A and G-CSF, neutrophil production, and neutrophil survival. In patients, we observed an increase in the IFN-γ–to–IL-17A ratio in the peripheral blood during high-grade CRS and neutropenia. We have uncovered a biological basis for ICAHT and provide support for the use of IFN-γ blockade to reduce both CRS and neutropenia.
Authors
Payal Goala, Yongliang Zhang, Nolan Beatty, Allan Pavy, Shannon McSain, Cooper Sailer, Muhammad Junaid Tariq, Showkat Hamid, Eduardo Cortes Gomez, Jianmin Wang, Duna Massillon, Maxwell Ilecki, Justin C. Boucher, Constanza Savid-Frontera, Sae Bom Lee, Hiroshi Kotani, Meredith L. Stone, Michael D. Jain, Marco L. Davila
Abstract
Mixed hematopoietic chimerism after allogeneic hematopoietic cell transplantation (HCT) promotes tolerance of transplanted donor-matched solid organs, corrects autoimmunity, and could transform therapeutic strategies for autoimmune type 1 diabetes (T1D). However, development of nontoxic bone marrow conditioning protocols is needed to expand clinical use. We developed a chemotherapy-free, nonmyeloablative (NMA) conditioning regimen that achieves mixed chimerism and allograft tolerance across MHC barriers in NOD mice. We obtained durable mixed hematopoietic chimerism in prediabetic NOD mice using anti–CD117 monoclonal antibody, T cell depleting antibodies, JAK1/2 inhibition, and low-dose total body irradiation prior to transplantation of MHC-mismatched B6 hematopoietic cells, preventing diabetes in 100% of chimeric NOD:B6 mice. In overtly diabetic NOD mice, NMA conditioning followed by combined B6 HCT and islet transplantation durably corrected diabetes in 100% of chimeric mice without chronic immunosuppression or graft-versus-host disease (GVHD). Chimeric mice remained immunocompetent, as assessed by blood count recovery and rejection of third-party allogeneic islets. Adoptive transfer studies and analysis of autoreactive T cells confirmed correction of autoimmunity. Analysis of chimeric NOD mice revealed central thymic deletion and peripheral tolerance mechanisms. Thus, with NMA conditioning and cell transplantation, we achieved durable hematopoietic chimerism without GVHD, promoted islet allograft tolerance, and reversed established T1D.
Authors
Preksha Bhagchandani, Stephan A. Ramos, Bianca Rodriguez, Xueying Gu, Shiva Pathak, Yuqi Zhou, Yujin Moon, Nadia Nourin, Charles A. Chang, Jessica Poyser, Brenda J. Velasco, Weichen Zhao, Hye-Sook Kwon, Richard Rodriguez, Diego M. Burgos, Mario A. Miranda, Everett Meyer, Judith A. Shizuru, Seung K. Kim
Abstract
Demyelination associated microglia (DMAM) orchestrate the regenerative response to demyelination by clearing myelin debris and promoting oligodendrocyte maturation. Peroxisomal metabolism has emerged as a candidate regulator of DMAMs, though the cell-intrinsic contribution in microglia remains undefined. Here we elucidate the role of peroxisome integrity in DMAMs, using cuprizone-mediated demyelination coupled with conditional KO of peroxisome biogenesis factor 5 (PEX5) in microglia. Absent demyelination, PEX5 conditional KO (PEX5cKO) had minimal impact on homeostatic microglia. However, during cuprizone-induced demyelination, the emergence of DMAMs unmasked a critical requirement for peroxisome integrity. At peak demyelination, PEX5cKO DMAMs exhibited increased lipid droplet burden and reduced lipophagy suggestive of impaired lipid catabolism. Although lipid droplet burden declined during the remyelination phase, PEX5cKO DMAMs accumulated intralysosomal crystals and curvilinear profiles, features that were largely absent in controls. Aberrant lipid processing was accompanied by elevated numbers of lysosomal damage markers and downregulation of the lipid exporter gene Apoe, consistent with defective lipid clearance. Furthermore, the disruptions in PEX5cKO DMAMs were associated with defective myelin debris clearance and impaired remyelination. Together, these findings delineate a stage-specific role for peroxisomes in coordinating lipid processing pathways essential to DMAM function and for enabling a pro-remyelinating environment.
Authors
Joseph A. Barnes-Vélez, Xiaohong Zhang, Yaren L. Peña Señeriz, Kiersten A. Scott, Yinglu Guan, Jian Hu
Abstract
The increased prevalence of GluA2-lacking, Ca2+-permeable AMPA receptors (CP-AMPARs) at spinal cord sensory synapses amplifies nociceptive transmission and maintains chronic neuropathic pain. Nerve injury–induced upregulation of α2δ-1 disrupts the assembly of GluA1/GluA2 heteromers, favoring the synaptic incorporation of GluA1 homotetramers in the spinal dorsal horn. Although GluA1-GluA3 subunits are broadly expressed, whether α2δ-1 regulates GluA3-containing AMPARs remains unknown. Here, we unexpectedly found that coexpression with α2δ-1 — but not α2δ-2 or α2δ-3 — diminished GluA3 AMPAR currents and protein levels, an effect blocked by pregabalin, an α2δ-1 C-terminus peptide, or proteasome inhibition. Both nerve injury and α2δ-1 overexpression reduced protein levels of GluA3 and GluA2/GluA3 heteromers in the spinal cord. Furthermore, α2δ-1 coexpression or nerve injury increased GluA3 ubiquitination, with K861 at the C-terminus of GluA3 identified as a key ubiquitination site mediating α2δ-1–induced GluA3 degradation. Additionally, intrathecal delivery of the Gria3 gene reversed nerve injury–induced nociceptive hypersensitivity and synaptic CP-AMPARs by restoring protein levels of GluA3 and GluA2/GluA3 heteromers in the spinal cord. These findings reveal that α2δ-1 promotes GluA1 homotetramer assembly and synaptic CP-AMPAR expression by driving ubiquitin-proteasome–mediated degradation of GluA3, providing insights into the molecular mechanisms of neuropathic pain and the therapeutic actions of gabapentinoids.
Authors
Meng-Hua Zhou, Shao-Rui Chen, Daozhong Jin, Yuying Huang, Hong Chen, Guanxing Chen, Jiusheng Yan, Hui-Lin Pan
Abstract
There is an urgent need to find targeted agents for T cell acute lymphoblastic leukemia (T-ALL). NOTCH1 is the most frequently mutated oncogene in T-ALL, but clinical trials showed that pan-Notch inhibitors caused dose-limiting toxicities. Thus, we shifted our focus to ETS1, which is one of the transcription factors that most frequently co-bind Notch-occupied regulatory elements in the T-ALL context. To identify the most essential enhancers, we performed a genome-wide CRISPRi screen of the strongest ETS1-dependent regulatory elements. The top-ranked element is located in an intron of AHI1 that interacts with the MYB promoter and is amplified with MYB in approximately 8.5% of patients with T-ALL. Using mouse models, we showed that this enhancer promoted self-renewal of hematopoietic stem cells and T cell leukemogenesis, maintained early T cell precursors, and restrained myeloid expansion with aging. We named this enhancer the hematopoietic stem cell MYB enhancer (H-Me). The H-Me showed limited activity and function in committed T cell progenitors but was accessed during leukemogenesis. In one T-ALL context, ETS1 bound the ETS motif in the H-Me to recruit cBAF to promote chromatin accessibility and activation. ETS1 or cBAF degraders impaired H-Me function. Thus, we identified a targetable stem cell element that was co-opted for T cell transformation.
Authors
Carea Mullin, Karena Lin, Elizabeth Choe, Cher Sha, Zeel Shukla, Koral Campbell, Anna C. McCarter, Annie Wang, Jannaldo Nieves-Salva, Sarah Khan, Theresa M. Keeley, Shannon Liang, Qing Wang, Ashley F. Melnick, Pearl Evans, Alexander C. Monovich, Ashwin Iyer, Rohan Kodgule, Yamei Deng, Felipe da Veiga Leprevost, Kelly R. Barnett, Petri Pölönen, Rami Khoriaty, Daniel Savic, David T. Teachey, Charles G. Mullighan, Marcin Cieslik, Alexey I. Nesvizhskii, Linda C. Samuelson, Morgan Jones, Qing Li, Russell J.H. Ryan, Mark Y. Chiang
Abstract
Chronic inflammation leads to tissue fibrosis, which can disrupt the function of the parenchyma of the organ and ultimately lead to organ failure. The most prevalent form of this occurs in chronic hepatitis, which leads to liver fibrosis and, ultimately, cirrhosis and hepatic failure. Although there is no specific treatment for fibrosis, the phosphodiesterase 4 (PDE4) competitive inhibitors have been shown to ameliorate fibrosis in rodent models. However, competitive inhibitors of PDE4 have shown significantly reduced effectiveness due to severe gastrointestinal side effects. The PDE4 family is composed of 4 genes (PDE4A–D), with each having up to 9 differentially spliced isoforms. Here, we report that PDE4D expression is specifically elevated during the hepatic fibrosis stage of liver disease progression. Furthermore, the expression of the long isoforms of PDE4D is selectively elevated in activated hepatic stellate cells, leading to the enhanced accumulation of extracellular matrix components. In a mouse model of liver fibrosis, genetic ablation of PDE4D or pharmacological inhibition using D159687, a selective allosteric inhibitor targeting the long isoforms of PDE4D, suppresses the expression of inflammatory and profibrogenic genes. These findings establish the long isoforms of PDE4D as key drivers of liver fibrosis and highlight their potential as therapeutic targets to ameliorate liver fibrosis.
Authors
Jeonghan Kim, Heeeun Yoon, Seoung Chan Joe, Antoine Smith, Jinsung Park, Geunhye Hong, Ji Myeong Ha, Eun Bae Kim, Ekihiro Seki, Myung K. Kim, Hae-Ock Lee, Ho-Shik Kim, Jay H. Chung
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ISSN: 0021-9738 (print), 1558-8238 (online)