PD-1/PD-L1 checkpoint therapy for cancer is commonly considered to act by reactivating T cells in the tumor microenvironment. Here, we present data from 2 mouse tumor models demonstrating an essential involvement of tumor-draining lymph nodes in PD-1 and PD-L1 therapeutic efficacy. Immune activation induced by checkpoint treatment was predominantly observed in the tumor-draining, but not nondraining, lymph nodes and was reflected in local accumulation of CD8+ T cells. Surgical resection of these lymph nodes, but not contralateral lymph nodes, abolished therapy-induced tumor regressions and was associated with decreased immune infiltrate in the tumor microenvironment. Moreover, inhibitor FTY720, which locks lymphocytes in lymph organs, also abrogated checkpoint therapy, suggesting that the tumor-draining lymph nodes function as sites of T cell invigoration required for checkpoint blockade therapy. Now that PD-1/PD-L1 checkpoint treatment is applied in earlier clinical stages of cancer, our preclinical data advocate for enrolling patients with their tumor-draining lymph nodes still in place, to optimally engage the antitumor immune response and thereby enhance clinical benefit.
Marieke F. Fransen, Mark Schoonderwoerd, Philipp Knopf, Marcel G.M. Camps, Lukas J.A.C. Hawinkels, Manfred Kneilling, Thorbald van Hall, Ferry Ossendorp
OXTR modulates a variety of behaviors in mammals, including social memory and recognition. Genetic and epigenetic dysregulation of OXTR has been suggested to be implicated in neuropsychiatric disorders, including autism spectrum disorder (ASD). While the involvement of DNA methylation is suggested, the mechanism underlying epigenetic regulation of OXTR is largely unknown. This has hampered the experimental design and interpretation of the results of epigenetic studies of OXTR in neuropsychiatric disorders. From the generation and characterization of a new line of Tet1 mutant mice — by deleting the largest coding exon 4 (Tet1Δe4) — we discovered for the first time to our knowledge that Oxtr has an array of mRNA isoforms and a complex transcriptional regulation. Select isoforms of Oxtr are significantly reduced in the brain of Tet1Δe4–/– mice. Accordingly, CpG islands of Oxtr are hypermethylated during early development and persist into adulthood. Consistent with the reduced express of OXTR, Tet1Δe4–/– mice display impaired maternal care, social behavior, and synaptic responses to oxytocin stimulation. Our findings elucidate a mechanism mediated by TET1 protein in regulating Oxtr expression by preventing DNA hypermethylation of Oxtr. The discovery of epigenetic dysregulation of Oxtr in TET1-deficient mouse brain supports the necessity of a reassessment of existing findings and a value of future studies of OXTR in neuropsychiatric disorders.
Aaron J. Towers, Martine W. Tremblay, Leeyup Chung, Xin-lei Li, Alexandra L. Bey, Wenhao Zhang, Xinyu Cao, Xiaoming Wang, Ping Wang, Lara J. Duffney, Stephen K. Siecinski, Sonia Xu, Yuna Kim, Xiangyin Kong, Simon Gregory, Wei Xie, Yong-hui Jiang
Symptomatic distal sensory polyneuropathy (sDSP) is common and debilitating in people with HIV/AIDS, leading to neuropathic pain, although the condition’s cause is unknown. To investigate biomarkers and associated pathogenic mechanisms for sDSP, we examined plasma miRNA profiles in HIV/AIDS patients with sDSP or without sDSP in 2 independent cohorts together with assessing related pathogenic effects. Several miRNAs were found to be increased in the Discovery Cohort (sDSP, n = 29; non-DSP, n = 40) by array analyses and were increased in patients with sDSP compared with patients without sDSP. miR–455-3p displayed a 12-fold median increase in the sDSP group, which was confirmed by machine learning analyses and verified by reverse transcription PCR. In the Validation Cohort (sDSP n = 16, non-DSP n = 20, healthy controls n = 15), significant upregulation of miR–455-3p was also observed in the sDSP group. Bioinformatics revealed that miR–455-3p targeted multiple host genes implicated in peripheral nerve maintenance, including nerve growth factor (NGF) and related genes. Transfection of cultured human dorsal root ganglia with miR–455-3p showed a concentration-dependent reduction in neuronal β-III tubulin expression. Human neurons transfected with miR–455-3p demonstrated reduced neurite outgrowth and NGF expression that was reversed by anti–miR–455-3p antagomir cotreatment. miR–455-3p represents a potential biomarker for HIV-associated sDSP and might also exert pathogenic effects leading to sDSP.
Eugene L. Asahchop, William G. Branton, Anand Krishnan, Patricia A. Chen, Dong Yang, Linglong Kong, Douglas W. Zochodne, Bruce J. Brew, M. John Gill, Christopher Power
In this study, the circulating miRNome from diagnostic neuroblastoma serum was assessed for identification of noninvasive biomarkers with potential in monitoring metastatic disease. After determining the circulating neuroblastoma miRNome, 743 miRNAs were screened in 2 independent cohorts of 131 and 54 patients. Evaluation of serum miRNA variance in a model testing for tumor stage, MYCN status, age at diagnosis, and overall survival revealed tumor stage as the most significant factor impacting miRNA abundance in neuroblastoma serum. Differential abundance analysis between patients with metastatic and localized disease revealed 9 miRNAs strongly associated with metastatic stage 4 disease in both patient cohorts. Increasing levels of these miRNAs were also observed in serum from xenografted mice bearing human neuroblastoma tumors. Moreover, murine serum miRNA levels were strongly associated with tumor volume. These findings were validated in longitudinal serum samples from metastatic neuroblastoma patients, where the 9 miRNAs were associated with disease burden and treatment response.
Fjoralba Zeka, Anneleen Decock, Alan Van Goethem, Katrien Vanderheyden, Fleur Demuynck, Tim Lammens, Hetty H. Helsmoortel, Joëlle Vermeulen, Rosa Noguera, Ana P. Berbegall, Valérie Combaret, Gudrun Schleiermacher, Geneviève Laureys, Alexander Schramm, Johannes H. Schulte, Sven Rahmann, Julie Bienertová-Vašků, Pavel Mazánek, Marta Jeison, Shifra Ash, Michael D. Hogarty, Mirthala Moreno-Smith, Eveline Barbieri, Jason Shohet, Frank Berthold, Tom Van Maerken, Frank Speleman, Matthias Fischer, Katleen De Preter, Pieter Mestdagh, Jo Vandesompele
Mono-ADP-ribosylation of an (arginine) protein catalyzed by ADP-ribosyltransferase 1 (ART1) — i.e., transfer of ADP-ribose from NAD to arginine — is reversed by ADP-ribosylarginine hydrolase 1 (ARH1) cleavage of the ADP-ribose–arginine bond. ARH1-deficient mice developed cardiomyopathy with myocardial fibrosis, decreased myocardial function under dobutamine stress, and increased susceptibility to ischemia/reperfusion injury. The membrane repair protein TRIM72 was identified as a substrate for ART1 and ARH1; ADP-ribosylated TRIM72 levels were greater in ARH1-deficient mice following ischemia/reperfusion injury. To understand better the role of TRIM72 and ADP-ribosylation, we used C2C12 myocytes. ARH1 knockdown in C2C12 myocytes increased ADP-ribosylation of TRIM72 and delayed wound healing in a scratch assay. Mutant TRIM72 (R207K, R260K) that is not ADP-ribosylated interfered with assembly of TRIM72 repair complexes at a site of laser-induced injury. The regulatory enzymes ART1 and ARH1 and their substrate TRIM72 were found in multiple complexes, which were coimmunoprecipitated from mouse heart lysates. In addition, the mono-ADP-ribosylation inhibitors vitamin K1 and novobiocin inhibited oligomerization of TRIM72, the mechanism by which TRIM72 is recruited to the site of injury. We propose that a mono-ADP-ribosylation cycle involving recruitment of TRIM72 and other regulatory factors to sites of membrane damage is critical for membrane repair and wound healing following myocardial injury.
Hiroko Ishiwata-Endo, Jiro Kato, Akihiko Tonouchi, Youn Wook Chung, Junhui Sun, Linda A. Stevens, Jianfeng Zhu, Angel M. Aponte, Danielle A. Springer, Hong San, Kazuyo Takeda, Zu-Xi Yu, Victoria Hoffmann, Elizabeth Murphy, Joel Moss
RBC alloimmunization represents a significant immunological challenge for patients requiring lifelong transfusion support. The majority of clinically relevant non-ABO(H) blood group antigens have been thought to drive antibody formation through T cell–dependent immune pathways. Thus, we initially sought to define the role of CD4+ T cells in formation of alloantibodies to KEL, one of the leading causes of hemolytic transfusion reactions. Unexpectedly, our findings demonstrated that KEL RBCs actually possess the ability to induce antibody formation independent of CD4+ T cells or complement component 3 (C3), two common regulators of antibody formation. However, despite the ability of KEL RBCs to induce anti-KEL antibodies in the absence of complement, removal of C3 or complement receptors 1 and 2 (CR1/2) rendered recipients completely reliant on CD4+ T cells for IgG anti-KEL antibody formation. Together, these findings suggest that C3 may serve as a novel molecular switch that regulates the type of immunological pathway engaged following RBC transfusion.
Amanda Mener, Seema R. Patel, Connie M. Arthur, Satheesh Chonat, Andreas Wieland, Manjula Santhanakrishnan, Jingchun Liu, Cheryl L. Maier, Ryan P. Jajosky, Kathryn Girard-Pierce, Ashley Bennett, Patricia E. Zerra, Nicole H. Smith, Jeanne E. Hendrickson, Sean R. Stowell
Obesity is characterized by accumulation of adipose tissue and is one the most important risk factors in the development of insulin resistance. Carbon monoxide–releasing (CO-releasing) molecules (CO-RMs) have been reported to improve the metabolic profile of obese mice, but the underlying mechanism remains poorly defined. Here, we show that oral administration of CORM-401 to obese mice fed a high-fat diet (HFD) resulted in a significant reduction in body weight gain, accompanied by a marked improvement in glucose homeostasis. We further unmasked an action we believe to be novel, by which CO accumulates in visceral adipose tissue and uncouples mitochondrial respiration in adipocytes, ultimately leading to a concomitant switch toward glycolysis. This was accompanied by enhanced systemic and adipose tissue insulin sensitivity, as indicated by a lower blood glucose and increased Akt phosphorylation. Our findings indicate that the transient uncoupling activity of CO elicited by repetitive administration of CORM-401 is associated with lower weight gain and increased insulin sensitivity during HFD. Thus, prototypic compounds that release CO could be investigated for developing promising insulin-sensitizing agents.
Laura Braud, Maria Pini, Lucie Muchova, Sylvie Manin, Hiroaki Kitagishi, Daigo Sawaki, Gabor Czibik, Julien Ternacle, Geneviève Derumeaux, Roberta Foresti, Roberto Motterlini
The mitochondrial Ca2+ uniporter (MCU) complex mediates acute mitochondrial Ca2+ influx. In skeletal muscle, MCU links Ca2+ signaling to energy production by directly enhancing the activity of key metabolic enzymes in the mitochondria. Here, we examined the role of MCU in skeletal muscle development and metabolic function by generating mouse models for the targeted deletion of Mcu in embryonic, postnatal, and adult skeletal muscle. Loss of Mcu did not affect muscle growth and maturation or otherwise cause pathology. Skeletal muscle–specific deletion of Mcu in mice also did not affect myofiber intracellular Ca2+ handling, but it did inhibit acute mitochondrial Ca2+ influx and mitochondrial respiration stimulated by Ca2+, resulting in reduced acute exercise performance in mice. However, loss of Mcu also resulted in enhanced muscle performance under conditions of fatigue, with a preferential shift toward fatty acid metabolism, resulting in reduced body fat with aging. Together, these results demonstrate that MCU-mediated mitochondrial Ca2+ regulation underlies skeletal muscle fuel selection at baseline and under enhanced physiological demands, which affects total homeostatic metabolism.
Jennifer Q. Kwong, Jiuzhou Huo, Michael J. Bround, Justin G. Boyer, Jennifer A. Schwanekamp, Nasab Ghazal, Joshua T. Maxwell, Young C. Jang, Zaza Khuchua, Kevin Shi, Donald M. Bers, Jennifer Davis, Jeffery D. Molkentin
The mechanisms of J wave syndrome (JWS) are incompletely understood. Here, we showed that the concomitant activation of small-conductance calcium-activated potassium (SK) current (IKAS) and inhibition of sodium current by cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine (CyPPA) recapitulate the phenotypes of JWS in Langendorff-perfused rabbit hearts. CyPPA induced significant J wave elevation and frequent spontaneous ventricular fibrillation (SVF), as well as sinus bradycardia, atrioventricular block, and intraventricular conduction delay. IKAS activation by CyPPA resulted in heterogeneous shortening of action potential (AP) duration (APD) and repolarization alternans. CyPPA inhibited cardiac sodium current (INa) and decelerated AP upstroke and intracellular calcium transient. SVFs were typically triggered by short-coupled premature ventricular contractions, initiated with phase 2 reentry and originated more frequently from the right than the left ventricles. Subsequent IKAS blockade by apamin reduced J wave elevation and eliminated SVF. β-Adrenergic stimulation was antiarrhythmic in CyPPA-induced electrical storm. Like CyPPA, hypothermia (32.0°C) also induced J wave elevation and SVF. It facilitated negative calcium-voltage coupling and phase 2 repolarization alternans with spatial and electromechanical discordance, which were ameliorated by apamin. These findings suggest that IKAS activation contributes to the development of JWS in rabbit ventricles.
Mu Chen, Dong-Zhu Xu, Adonis Z. Wu, Shuai Guo, Juyi Wan, Dechun Yin, Shien-Fong Lin, Zhenhui Chen, Michael Rubart-von der Lohe, Thomas H. Everett IV, Zhilin Qu, James N. Weiss, Peng-Sheng Chen
Paramount to the efficacy of immune checkpoint inhibitors is proper selection of patients with adequate tumor immunogenicity and a robust but suppressed immune infiltrate. In colon cancer, immune-based therapies are approved for patients with DNA mismatch repair (MMR) deficiencies, in whom accumulation of genetic mutations results in increased neoantigen expression, triggering an immune response that is suppressed by the PD-L1/PD-1 pathway. Here, we report that characterization of the microenvironment of MMR-deficient metastatic colorectal cancer using multiplex fluorescent immunohistochemistry (mfIHC) identified increased infiltration of cytotoxic T lymphocytes (CTLs), which were more often engaged with epithelial cells (ECs) and improved overall survival. A subset of patients with intact MMR but a similar immune microenvironment to MMR-deficient patients was identified and found to universally express high levels of PD-L1, suggesting that they may represent a currently untreated, checkpoint inhibitor–responsive population. Further, PD-L1 expression on antigen-presenting cells (APCs) in the tumor microenvironment (TME) resulted in impaired CTL/EC engagement and enhanced infiltration and engagement of Tregs. Characterization of the TME by mfIHC highlights the interconnection between immunity and immunosuppression in metastatic colon cancer and may better stratify patients for receipt of immunotherapies.
Jenny Lazarus, Tomasz Maj, J. Joshua Smith, Mirna Perusina Lanfranca, Arvind Rao, Michael I. D’Angelica, Lawrence Delrosario, Alexander Girgis, Casey Schukow, Jinru Shia, Ilona Kryczek, Jiaqi Shi, Isaac Wasserman, Howard Crawford, Hari Nathan, Marina Pasca Di Magliano, Weiping Zou, Timothy L. Frankel
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