Despite the rare appearance of potent HIV-neutralizing mAbs in infected individuals requiring prolonged affinity maturation, little is known regarding this process in the majority of viremic individuals. HIV-infected individuals with chronic HIV viremia have elevated numbers of nonconventional tissue-like memory (TLM) B cells that predominate in blood over conventional resting memory (RM) B cells. Accordingly, we investigated affinity maturation in these 2 memory B cell populations. Analysis of IgG-expressing TLM B cells revealed a higher number of cell divisions compared with RM B cells; however, TLM B cells paradoxically displayed significantly lower frequencies of somatic hypermutation (SHM). To assess Ab reactivity in TLM and RM B cells, single-cell cloning was performed on HIV envelope CD4–binding site–sorted (CD4bs-sorted) B cells from 3 individuals with chronic HIV viremia. Several clonal families were present among the 127 cloned recombinant mAbs, with evidence of crosstalk between TLM and RM B cell populations that was largely restricted to non-VH4 families. Despite evidence of common origins, SHM frequencies were significantly decreased in TLM-derived mAbs compared with SHM frequencies in RM-derived mAbs. However, both cell populations had lower frequencies of SHMs than did broadly neutralizing CD4bs–specific mAbs. There was a significant correlation between SHM frequencies and the HIV-neutralizing capacities of the mAbs. Furthermore, HIV neutralization was significantly higher in the RM-derived mAbs compared with that seen in the TLM-derived mAbs, and both SHM frequencies and neutralizing capacity were lowest in TLM-derived mAbs with high polyreactivity. Thus, deficiencies in memory B cells that arise during chronic HIV viremia provide insight into the inadequacy of the Ab response in viremic individuals.
Eric Meffre, Aaron Louie, Jason Bannock, Leo J.Y. Kim, Jason Ho, Cody C. Frear, Lela Kardava, Wei Wang, Clarisa M. Buckner, Yimeng Wang, Olivia R. Fankuchen, Kathleen R. Gittens, Tae-Wook Chun, Yuxing Li, Anthony S. Fauci, Susan Moir
The capacity of pancreatic β cells to maintain glucose homeostasis during chronic physiologic and immunologic stress is important for cellular and metabolic homeostasis. Insulin receptor substrate 2 (IRS2) is a regulated adapter protein that links the insulin and IGF1 receptors to downstream signaling cascades. Since strategies to maintain or increase IRS2 expression can promote β cell growth, function, and survival, we conducted a screen to find small molecules that can increase IRS2 mRNA in isolated human pancreatic islets. We identified 77 compounds, including 15 that contained a tricyclic core. To establish the efficacy of our approach, one of the tricyclic compounds, trimeprazine tartrate, was investigated in isolated human islets and in mouse models. Trimeprazine is a first-generation antihistamine that acts as a partial agonist against the histamine H1 receptor (H1R) and other GPCRs, some of which are expressed on human islets. Trimeprazine promoted CREB phosphorylation and increased the concentration of IRS2 in islets. IRS2 was required for trimeprazine to increase nuclear Pdx1, islet mass, β cell replication and function, and glucose tolerance in mice. Moreover, trimeprazine synergized with anti-CD3 Abs to reduce the progression of diabetes in NOD mice. Finally, it increased the function of human islet transplants in streptozotocin-induced (STZ-induced) diabetic mice. Thus, trimeprazine, its analogs, or possibly other compounds that increase IRS2 in islets and β cells without adverse systemic effects might provide mechanism-based strategies to prevent the progression of diabetes.
Alexandra Kuznetsova, Yue Yu, Jennifer Hollister-Lock, Lynn Opare-Addo, Aldo Rozzo, Marianna Sadagurski, Lisa Norquay, Jessica E. Reed, Ilham El Khattabi, Susan Bonner-Weir, Gordon C. Weir, Arun Sharma, Morris F. White
FMS-like tyrosine kinase 3–targeted (FLT3-targeted) therapies have shown initial promise for the treatment of acute myeloid leukemia (AML) expressing FLT3-activating mutations; however, resistance emerges rapidly. Furthermore, limited options exist for the treatment of FLT3-independent AML, demonstrating the need for novel therapies that reduce toxicity and improve survival. MERTK receptor tyrosine kinase is overexpressed in 80% to 90% of AMLs and contributes to leukemogenesis. Here, we describe MRX-2843, a type 1 small-molecule tyrosine kinase inhibitor that abrogates activation of both MERTK and FLT3 and their downstream effectors. MRX-2843 treatment induces apoptosis and inhibits colony formation in AML cell lines and primary patient samples expressing MERTK and/or FLT3-ITD, with a wide therapeutic window compared with that of normal human cord blood cells. In murine orthotopic xenograft models, once-daily oral therapy prolonged survival 2- to 3-fold over that of vehicle-treated controls. Additionally, MRX-2843 retained activity against quizartinib-resistant FLT3-ITD–mutant proteins with clinically relevant alterations at the D835 or F691 loci and prolonged survival in xenograft models of quizartinib-resistant AML. Together, these observations validate MRX-2843 as a translational agent and support its clinical development for the treatment of AML.
Katherine A. Minson, Catherine C. Smith, Deborah DeRyckere, Clara Libbrecht, Alisa B. Lee-Sherick, Madeline G. Huey, Elisabeth A. Lasater, Gregory D. Kirkpatrick, Michael A. Stashko, Weihe Zhang, Craig T. Jordan, Dmitri Kireev, Xiaodong Wang, Stephen V. Frye, H. Shelton Earp, Neil P. Shah, Douglas K. Graham
The 2p15p16.1 microdeletion syndrome has a core phenotype consisting of intellectual disability, microcephaly, hypotonia, delayed growth, common craniofacial features, and digital anomalies. So far, more than 20 cases of 2p15p16.1 microdeletion syndrome have been reported in the literature; however, the size of the deletions and their breakpoints vary, making it difficult to identify the candidate genes. Recent reports pointed to 4 genes (
Hani Bagheri, Chansonette Badduke, Ying Qiao, Rita Colnaghi, Iga Abramowicz, Diana Alcantara, Christopher Dunham, Jiadi Wen, Robert S. Wildin, Malgorzata J.M. Nowaczyk, Jennifer Eichmeyer, Anna Lehman, Bruno Maranda, Sally Martell, Xianghong Shan, Suzanne M.E. Lewis, Mark O’Driscoll, Cheryl Y. Gregory-Evans, Evica Rajcan-Separovic
Preeclampsia (PE) is a disorder of pregnancy that manifests as late gestational maternal hypertension and proteinuria and can be life-threatening to both the mother and baby. It is believed that abnormal placentation is responsible for the cascade of events leading to the maternal syndrome. Embryo implantation is critical to establishing a healthy pregnancy. Defective implantation can cause adverse “ripple effects,” leading to abnormal decidualization and placentation, retarded fetal development, and poor pregnancy outcomes, such as PE and fetal growth restriction. The precise mechanism(s) of implantation defects that lead to PE remain elusive. BPH/5 mice, which spontaneously develop the cardinal features of PE, show peri-implantation defects including upregulation of Cox2 and IL-15 at the maternal-fetal interface. This was associated with decreased decidual natural killer (dNK) cells, which have important roles in establishing placental perfusion. Interestingly, a single administration of a Cox2 inhibitor (celecoxib) during decidualization restrained Cox2 and IL-15 expression, restored dNK cell numbers, improved fetal growth, and attenuated late gestational hypertension in BPH/5 female mice. This study provides evidence that decidual overexpression of Cox2 and IL-15 may trigger the adverse pregnancy outcomes reflected in the preeclamptic syndrome, underscoring the idea that Cox2 inhibitor treatment is an effective strategy for the prevention of PE-associated fetal and maternal morbidity and mortality.
Jenny L. Sones, Jeeyeon Cha, Ashley K. Woods, Amanda Bartos, Christa Y. Heyward, Heinrich E. Lob, Catherine E. Isroff, Scott D. Butler, Stephanie E. Shapiro, Sudhansu K. Dey, Robin L. Davisson
Glioblastomas are highly infiltrated by diverse immune cells, including microglia, macrophages, and myeloid-derived suppressor cells (MDSCs). Understanding the mechanisms by which glioblastoma-associated myeloid cells (GAMs) undergo metamorphosis into tumor-supportive cells, characterizing the heterogeneity of immune cell phenotypes within glioblastoma subtypes, and discovering new targets can help the design of new efficient immunotherapies. In this study, we performed a comprehensive battery of immune phenotyping, whole-genome microarray analysis, and microRNA expression profiling of GAMs with matched blood monocytes, healthy donor monocytes, normal brain microglia, nonpolarized M0 macrophages, and polarized M1, M2a, M2c macrophages. Glioblastoma patients had an elevated number of monocytes relative to healthy donors. Among CD11b+ cells, microglia and MDSCs constituted a higher percentage of GAMs than did macrophages. GAM profiling using flow cytometry studies revealed a continuum between the M1- and M2-like phenotype. Contrary to current dogma, GAMs exhibited distinct immunological functions, with the former aligned close to nonpolarized M0 macrophages.
Konrad Gabrusiewicz, Benjamin Rodriguez, Jun Wei, Yuuri Hashimoto, Luke M. Healy, Sourindra N. Maiti, Ginu Thomas, Shouhao Zhou, Qianghu Wang, Ahmed Elakkad, Brandon D. Liebelt, Nasser K. Yaghi, Ravesanker Ezhilarasan, Neal Huang, Jeffrey S. Weinberg, Sujit S. Prabhu, Ganesh Rao, Raymond Sawaya, Lauren A. Langford, Janet M. Bruner, Gregory N. Fuller, Amit Bar-Or, Wei Li, Rivka R. Colen, Michael A. Curran, Krishna P. Bhat, Jack P. Antel, Laurence J. Cooper, Erik P. Sulman, Amy B. Heimberger
The cardioprotective inducible enzyme heme oxygenase-1 (HO-1) degrades prooxidant heme into equimolar quantities of carbon monoxide, biliverdin, and iron. We hypothesized that HO-1 mediates cardiac protection, at least in part, by regulating mitochondrial quality control. We treated WT and HO-1 transgenic mice with the known mitochondrial toxin, doxorubicin (DOX). Relative to WT mice, mice globally overexpressing human HO-1 were protected from DOX-induced dilated cardiomyopathy, cardiac cytoarchitectural derangement, and infiltration of CD11b+ mononuclear phagocytes. Cardiac-specific overexpression of HO-1 ameliorated DOX-mediated dilation of the sarcoplasmic reticulum as well as mitochondrial disorganization in the form of mitochondrial fragmentation and increased numbers of damaged mitochondria in autophagic vacuoles. HO-1 overexpression promotes mitochondrial biogenesis by upregulating protein expression of NRF1, PGC1α, and TFAM, which was inhibited in WT animals treated with DOX. Concomitantly, HO-1 overexpression inhibited the upregulation of the mitochondrial fission mediator Fis1 and resulted in increased expression of the fusion mediators, Mfn1 and Mfn2. It also prevented dynamic changes in the levels of key mediators of the mitophagy pathway, PINK1 and parkin. Therefore, these findings suggest that HO-1 has a novel role in protecting the heart from oxidative injury by regulating mitochondrial quality control.
Travis D. Hull, Ravindra Boddu, Lingling Guo, Cornelia C. Tisher, Amie M. Traylor, Bindiya Patel, Reny Joseph, Sumanth D. Prabhu, Hagir B. Suliman, Claude A. Piantadosi, Anupam Agarwal, James F. George
Over the past 8 years, the discovery of 11 new human polyomaviruses (HPyVs) has revived interest in this DNA tumor virus family. Although HPyV infection is widespread and largely asymptomatic, one of these HPyVs, Merkel cell polyomavirus (MCV), is a bona fide human tumor virus. JC virus (JCV), BK virus, HPyV7, and trichodysplasia-spinulosa virus (TSV) can cause nonneoplastic diseases in the setting of immunosuppression. Few specific reagents are available to study the biology of the newly discovered HPyVs. We developed a pan-HPyV-screening method using a cocktail of 3 antibodies that, when combined, recognize T antigen proteins of all HPyVs. We validated detection characteristics of the antibody cocktail by immunoblotting and immunohistochemistry and screened 1,184 cases, including well-defined diseases and tumor tissue microarrays. This assay robustly detected MCV, TSV, JCV, and HPyV7 in etiologically related diseases. We further identified WU polyomavirus in a case of chronic lymphocytic lymphoma-associated bronchitis. Except for scattered, incidentally infected cells in 5% of lung squamous cell carcinomas and colon adenocarcinomas, a broad panel of tumor tissues was largely negative for infection by any HPyV. This method eliminates known HPyVs as suspected causes of cancers investigated in this study. Pan-HPyV survey can be applied to identify diseases associated with recently discovered polyomaviruses.
Tuna Toptan, Samuel A. Yousem, Jonhan Ho, Yuki Matsushima, Laura P. Stabile, Maria-Teresa Fernández-Figueras, Rohit Bhargava, Akihide Ryo, Patrick S. Moore, Yuan Chang
Juvenile idiopathic arthritis (JIA) is the most common pediatric rheumatological condition. Although it has been proposed that JIA has an autoimmune component, the autoantigens are still unknown. Using biochemical and proteomic approaches, we identified the molecular chaperone transthyretin (TTR) as an antigenic target for B and T cell immune responses. TTR was eluted from IgG complexes and affinity purified from 3 JIA patients, and a statistically significant increase in TTR autoantibodies was observed in a group of 43 JIA patients. Three cryptic, HLA-DR1–restricted TTR peptides, which induced CD4+ T cell expansion and IFN-γ and TNF-α production in 3 out of 17 analyzed patients, were also identified. Misfolding, aggregation and oxidation of TTR, as observed in the synovial fluid of all JIA patients, enhanced its immunogenicity in HLA-DR1 transgenic mice. Our data point to TTR as an autoantigen potentially involved in the pathogenesis of JIA and to oxidation and aggregation as a mechanism facilitating TTR autoimmunity.
Cristina C. Clement, Halima Moncrieffe, Aditi Lele, Ginger Janow, Aniuska Becerra, Francesco Bauli, Fawzy A. Saad, Giorgio Perino, Cristina Montagna, Neil Cobelli, John Hardin, Lawrence J. Stern, Norman Ilowite, Steven A. Porcelli, Laura Santambrogio
Noelia Escobedo, Steven T. Proulx, Sinem Karaman, Miriam E. Dillard, Nicole Johnson, Michael Detmar, Guillermo Oliver
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