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Abstract
Development of gastric cancer is often preceded by chronic inflammation, but the immune cellular mechanisms underlying this process are unclear. Here we demonstrated that an inflammasome molecule, absent in melanoma 2 (Aim2), was upregulated in gastric cancer patients, and in spasmolytic polypeptide-expressing metaplasia (SPEM) of chronically Helicobacter felis (H. felis)-infected stomachs in mice. However, we found that Aim2 was not necessary for inflammasome function during gastritis. In contrast, Aim2 deficiency led to an increase in gastric CD8+ T cell frequency, which exacerbated metaplasia. These gastric CD8+ T cells from Aim2-/- mice were found to have lost their homing receptor expression (S1pr1 and CD62l), a feature of tissue resident memory T cells (TRM). The process was not mediated by Aim2-dependent regulation of IFN-β, or by dendritic cell-intrinsic Aim2. Rather, Aim2 deficiency contributed to an increased production of Cxcl16 by B cells, which could suppress S1pr1 and CD62l in CD8+ T cells. The study describes a novel function of Aim2 that regulates CD8+ T cell infiltration and retention within chronically inflamed solid organ tissue. This function operates independently of the inflammasome, IFN-β or dendritic cells. We provide evidence that B cells can contribute to this mechanism via Cxcl16.
Authors
Mohamad El-Zaatari, Shrinivas Bishu, Min Zhang, Helmut Grasberger, Guoqing Hou, Henry R. Haley, Brock A. Humphries, Li-Jyun Syu, Andrzej Dlugosz, Kathryn E. Luker, Gary Luker, Kathryn A. Eaton, Nobuhiko Kamada, Marilia Cascalho, John Y. Kao
Abstract
Small primary breast cancers can show surprisingly high potential for metastasis. Clinical decision making for tumor aggressiveness, including molecular profiling, relies primarily on analysis of the cancer cells. Here we show that this is insufficient; that the stromal microenvironment of the primary tumor plays a key role in tumor-cell dissemination and implantation at distant sites. We previously described two cancer-associated fibroblasts (CAFs) that either express (CD146pos) or lack (CD146neg) CD146 (official symbol MCAM; alias MUC18). We now find that when mixed with human breast cancer cells, each fibroblast subtype determines the fate of cancer-cells: CD146neg fibroblasts promote increased metastasis compared to CD146pos fibroblasts. Novel quantitative and qualitative proteomic analyses show that CD146pos CAFs produce an environment rich in basement membrane proteins, while CD146neg CAFs exhibit increases in FN1, LOX, and TNC; all over-expressed in aggressive disease. We also show clinically, that CD146neg CAFs predict for likelihood of lymph node involvement even in small primary tumors (<5 cm). Clearly small tumors enriched for CD146neg CAFs require aggressive treatments.
Authors
Heather M. Brechbuhl, Alexander S. Barrett, Etana Kopin, Jaime C. Hagen, Amy L. Han, Austin E. Gillen, Jessica Finlay-Schultz, Diana M. Cittelly, Philip Owens, Kathryn B. Horwitz, Carol A. Sartorius, Kirk C. Hansen, Peter Kabos
Abstract
BACKGROUND. The relative stabilities of the intact and defective HIV genomes over time during effective antiretroviral therapy (ART) have not been fully characterized. METHODS. We used the intact proviral DNA assay (IPDA) to estimate the rate of change of intact and defective proviruses in HIV-infected adults on ART over several years. We used linear spline models with a knot at seven years; these included a random intercept and slope up to the knot. We also estimated the influence of covariates on starting levels and rates of change. RESULTS. We studied 81 individuals for a median of 7.3 (IQR 5.9–9.6) years. In a model allowing for a change in the rate of decline, we found evidence for a more rapid rate of decline in intact genomes from initial suppression through seven years (15.7% per year decline; CI –22.8%, –8.0%) followed by a slower rate of decline after seven years (3.6% per year; CI –8.1%, +1.1%). The estimated half-life of the reservoir was 4.0 years (CI 2.7–8.3) until year seven and 18.7 years (CI 8.2–infinite) thereafter. There was substantial variability between individuals in the rate of decline until year seven. Intact provirus declined at a faster rate than defective provirus (P < 0.001). Individuals with higher CD4+ T cell nadir values had a faster rate of decline in intact provirus. CONCLUSIONS. These findings provide evidence that the biology of the replication-competent (intact) reservoir differs from that of the replication-incompetent (non-intact) pool of proviruses. The IPDA will likely be informative when investigating the impact of interventions targeting the reservoir. FUNDING. This work was supported the Delaney AIDS Research Enterprise (DARE; AI096109, A127966). The SCOPE cohort receives additional support from the UCSF/Gladstone Institute of Virology & Immunology CFAR (P30 AI027763), the CFAR Network of Integrated Systems (R24 AI067039) and the amfAR Institute for HIV Cure Research (amfAR 109301). Additional support was provided by the I4C and Beat-HIV Collaboratories, the Howard Hughes Medical Institute, Gilead, and the Bill and Melinda Gates Foundation.
Authors
Michael J. Peluso, Peter Bacchetti, Kristen D. Ritter, Subul A. Beg, Jun Lai, Jeffrey N. Martin, Peter W. Hunt, Timothy J. Henrich, Janet D. Siliciano, Robert F. Siliciano, Gregory M. Laird, Steven G. Deeks
Abstract
Altered bone marrow hematopoiesis and immune suppression is a hallmark of myelodysplastic syndrome (MDS). While the bone marrow microenvironment influences malignant hematopoiesis, the mechanism leading to MDS-associated immune suppression is unknown. We tested whether mesenchymal stromal cells (MSCs) contribute to this process. Here, we developed a model to study cultured MSCs from MDS patients compared to similar aged matched normal controls for regulation of immune function. MSCs from MDS patients (MDS-MSC) and healthy donor MSC (HD-MSC) exhibited a similar in vitro phenotype and neither had a direct effect on NK cell function. However, when MDS and HD-MSCs were cultured with monocytes, only the MDS-MSCs acquired phenotypic and metabolic properties of myeloid-derived suppressor cells (MDSCs), with resulting suppression of NK cell function, along with T cell proliferation. A unique MSC transcriptome was observed in MDS-MSCs compared to HD-MSCs, including increased expression of the reactive oxygen species (ROS) regulator, ENC1. High ENC1 expression in MDS-MSC induced suppressive monocytes with increased INHBA, a gene that encodes for a member of the TGFβ superfamily of proteins. These monocytes also had reduced expression of the TGFβ transcriptional repressor MAB21L2, further adding to their immune suppressive function. Silencing ENC1 or inhibiting ROS production in MDS-MSCs abrogated the suppressive function of MDS-MSC conditioned monocytes. In addition, silencing MAB21L2 in healthy MSC conditioned monocytes mimicked the MDS-MSC suppressive transformation of monocytes. Our data demonstrate that MDS-MSCs are responsible for inducing an immune suppressive microenvironment in MDS through an indirect mechanism involving monocytes.
Authors
Dhifaf Sarhan, Jinhua Wang, Upasana Sunil Arvindam, Caroline Hallstrom, Michael R. Verneris, Bartosz Grzywacz, Erica Warlick, Bruce R. Blazar, Jeffrey S. Miller
Abstract
Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently-discovered damage-associated molecular pattern. Understanding the precise mechanism by which it exacerbates inflammation is essential. Here we identified that eCIRP is a new biologically active endogenous ligand of triggering receptor expressed on myeloid cells-1 (TREM-1), fueling inflammation in sepsis. Surface plasmon resonance revealed a strong binding affinity between eCIRP and TREM-1, and FRET assay confirmed eCIRP’s interaction with TREM-1 in macrophages. Targeting TREM-1 by its siRNA or a decoy peptide LP17 or by using TREM-1-/- mice dramatically reduced eCIRP-induced inflammation. We developed a novel 7-aa peptide derived from human eCIRP, M3, which blocked the interaction of TREM-1 and eCIRP. M3 suppressed inflammation induced by eCIRP or agonist TREM-1 Ab crosslinking in murine macrophages or human peripheral blood monocytes. M3 also inhibited eCIRP-induced systemic inflammation and tissue injury. Treatment with M3 further protected mice from sepsis, improved acute lung injury, and increased survival. Thus, we have discovered a novel TREM-1 ligand and developed a new peptide M3 to block the eCIRP-TREM-1 interaction and improve the outcomes in sepsis.
Authors
Naomi-Liza Denning, Monowar Aziz, Atsushi Murao, Steven D. Gurien, Mahendar Ochani, Jose M. Prince, Ping Wang
Abstract
Extracellular cold-inducible RNA-binding protein (eCIRP) is a damage-associated molecular pattern, whose effect on macrophages is not entirely elucidated. Here we identified that eCIRP promotes macrophage endotoxin tolerance. Septic mice had higher serum levels of eCIRP; this was associated with a reduced ex vivo immune response of their splenocytes to LPS. Pretreatment of macrophages with recombinant murine (rm) CIRP resulted in a tolerance to LPS stimulation as demonstrated by a significant reduction of TNF-α production. We found that eCIRP increased phosphorylation of STAT3 (pSTAT3) in macrophages. A STAT3 inhibitor, Stattic, rescued macrophages from rmCIRP-induced tolerance by restoring the release of TNF-α in response to LPS stimulation. We discovered strong binding affinity between eCIRP and IL-6R as revealed by Biacore, FRET, and their co-localization in macrophages by immunostaining assays. Blockade of IL-6R with its neutralizing Ab significantly inhibited eCIRP-induced pSTAT3 and restored LPS-stimulated TNF-α release in macrophages. Incubation of macrophages with rmCIRP skewed them towards a M2 phenotype, while treatment with anti-IL-6R Ab prevented rmCIRP-induced M2 polarization. Thus, we have demonstrated that eCIRP activates pSTAT3 via a novel receptor IL-6R to promote macrophage endotoxin tolerance. Targeting eCIRP appears to be a new therapeutic option to correct immune-tolerance in sepsis.
Authors
Mian Zhou, Monowar Aziz, Naomi-Liza Denning, Hao-Ting Yen, Gaifeng Ma, Ping Wang
Abstract
Recent studies have presented compelling evidence that it is not tissue-resident, but rather monocyte-derived alveolar macrophages (TR-AMs vs. Mo-AMs) are essential to development of experimental lung fibrosis. However, whether Apolipoprotein E (ApoE), which is produced abundantly by Mo-AMs in the lung, plays a role in the pathogenesis is unclear. In this study, we found that pulmonary ApoE was almost exclusively produced by Mo-AMs in mice with bleomycin induced lung fibrosis. We showed although ApoE was not necessary for developing maximal fibrosis in bleomycin injured lung, it was required for the resolution of this pathology. We found that ApoE directly bound to Collagen I and mediated Collagen I phagocytosis in vitro and in vivo, and this process was dependent on low density lipoprotein receptor-related protein 1 (LPR1). Furthermore, interference of ApoE/LRP1 interaction impaired the resolution of lung fibrosis in bleomycin treated wild-type mice. In contrast, supplementation of ApoE promoted this process in ApoE–/– animals. In conclusion, Mo-AM derived ApoE is beneficial to the resolution of lung fibrosis, supporting the notion that Mo-AMs may have distinct functions in different phases of lung fibrogenesis. The findings also suggest a novel therapeutic target for treating lung fibrosis, to which effective remedies remain scarce.
Authors
Huachun Cui, Dingyuan Jiang, Sami Banerjee, Na Xie, Tejaswini Kulkarni, Rui-Ming Liu, Steven R. Duncan, Gang Liu
Abstract
The mitochondrial calcium uniporter is widely accepted as the primary route of rapid calcium entry into mitochondria, where increases in matrix calcium contribute to bioenergetics but also mitochondrial permeability and cell death. Hence, regulation of uniporter activity is critical to mitochondrial homeostasis. The uniporter subunit EMRE is known to be an essential regulator of the channel-forming protein MCU in cell culture, but EMRE’s impact on organismal physiology is less understood. Here we characterize a novel mouse model of EMRE deletion and show that EMRE is indeed required for mitochondrial calcium uniporter function in vivo. EMRE–/– mice are born less frequently; however, the mice which are born are viable, healthy, and do not manifest overt metabolic impairment, at rest or with exercise. Finally, to investigate the role of EMRE in disease processes, we examine the effects of EMRE deletion in a muscular dystrophy model associated with mitochondrial calcium overload.
Authors
Julia C. Liu, Nicole C. Syder, Nima S. Ghorashi, Thomas B. Willingham, Randi J. Parks, Junhui Sun, Maria M. Fergusson, Jie Liu, Kira M. Holmström, Sara Menazza, Danielle A. Springer, Chengyu Liu, Brian Glancy, Toren Finkel, Elizabeth Murphy
Abstract
Decades ago, investigators reported that mice lacking DLX1 and DLX2, transcription factors expressed in the enteric nervous system (ENS), die with possible bowel motility problems. These problems were never fully elucidated. We found that mice lacking DLX1 and DLX2 (Dlx1/2-/- mice) had slower small bowel transit and reduced or absent neurally-mediated contraction complexes. In contrast, small bowel motility seemed normal in adult mice lacking DLX1 (Dlx1-/-). Even with detailed anatomic studies, we found no defects in ENS precursor migration, or neuron and glia density, in Dlx1/2-/- or Dlx1-/- mice. However, RNA sequencing of Dlx1/2-/- ENS revealed dysregulation of many genes, including vasoactive intestinal peptide (Vip). Our study reveals a novel connection between Dlx genes and Vip and highlights the observation that dangerous bowel motility problems can occur in the absence of easily identifiable ENS structural defects. These findings may be relevant for disorders like chronic intestinal pseudo-obstruction (CIPO) syndrome.
Authors
Christina M. Wright, James P. Garifallou, Sabine Schneider, Heather L. Mentch, Deepika R. Kothakapa, Beth A. Maguire, Robert O. Heuckeroth
Abstract
Cell therapy raises high hopes for better treatment of brain disorders. However, the majority of transplanted cells often die soon after transplantation and those that survive initially continue to die in the subacute phase, diminishing the impact of transplantations. In this study, we genetically modified transplanted human neural stem cells (hNSCs), from two distant embryonic SCs lines (H9 and RC17) to express one of four prosurvival factors – Hif1a, Akt1, Bcl-2, or Bcl-xl – and studied how these modifications improve short- and long-term survival of transplanted hNSCs. All genetic modifications dramatically increased survival of the transplanted hNSCs. Importantly, three out of four modifications also enhanced the exit of hNSCs from the cell cycle, thus avoiding aberrant growth of the transplants. Bcl-xl expression provided the strongest protection of transplanted cells, reducing both immediate and delayed cell death, and stimulated hNSC differentiation towards neuronal and oligodendroglial lineages. By designing hNSCs with drug-controlled expression of Bcl-xl, we demonstrated that short-term expression of a prosurvival factor can ensure the long-term survival of transplanted cells. Importantly, transplantation of Bcl-xl expressing hNSCs into mice suffering from stroke improved behavioral outcome and recovery of motor activity in mice.
Authors
Irina Korshunova, Sina Rhein, Diego García-González, Ines Stölting, Ulrich Pfisterer, Anna Barta, Oksana Dmytriyeva, Agnete Kirkeby, Markus Schwaninger, Konstantin Khodosevich
Abstract
In recent years, CAR-T cell therapy has proven to be a promising approach against cancer. Nonetheless, this approach still faces multiple challenges in eliminating solid tumors, one of which being the immunosuppressive tumor microenvironment (TME). Here we demonstrated that knocking out the endogenous TGFβ receptor II (TGFBR2) in CAR-T cells with CRISPR/Cas9 technology could reduce the induced regulatory T-cell (iTreg) conversion and prevent the exhaustion of CAR-T cells. Meanwhile, TGFBR2 edited CAR-T cells had better in vivo tumor elimination efficacy, both in cell line derived xenograft (CDX) and patient derived xenograft (PDX) solid tumor models, whether administered locally or systemically. In addition, the TGFBR2 edited CAR-T cells could eliminate contralaterally re-inoculated xenografts in mice effectively with an increased proportion of central memory and effector memory subsets. In conclusion, we greatly improved the in vitro and in vivo function of CAR-T cells in TGFβ-rich tumor environments by knocking out endogenous TGFBR2, proposing a new method to improve the efficacy of CAR-T cell therapy for treating solid tumors.
Authors
Na Tang, Chen Cheng, Xingying Zhang, Miaomiao Qiao, Na Li, Wei Mu, Xiao-Fei Wei, Weidong Han, Haoyi Wang
Abstract
The HIV latent reservoir in resting memory CD4+ T cells prevents cure. Therapeutics to reactivate and eliminate this reservoir are in clinical trials in adults, but not in pediatric populations. We determined, ex vivo, the inducibility and size of the latent reservoir in perinatal compared with adult infections using the Tat/rev Induced Limiting Dilution Assay (TILDA), in which a single-round (12hr) of CD4+ T cell stimulation with PMA/ionomycin maximally activates T cells and leads to proviral expression with multiply-spliced HIV RNA production. Markers of immune activation and exhaustion were measured to assess interactions with inducibility. Despite similar rates of T cell activation with PMA/ionomycin, the latent reservoir in perinatal infection is slower to reactivate and of lower magnitude compared to adult infection, independent of proviral load. An enhanced TILDA with the addition of phytohemagglutin and for 18 hours augmented proviral expression in perinatal but not adult infection. Baseline HLA–DR+ CD4+ T cells was significantly lower in perinatal compared with adult infections, but not correlated with induced reservoir size. These data support differences in baseline immune activation and kinetics of latency reversal in perinatal compared with adult infections, with implications for latency reversal strategies towards reservoir clearance and remission.
Authors
Adit Dhummakupt, Jessica H. Rubens, Thuy Anderson, Laura Powell, Bareng A.S. Nonyane, Lilly V. Siems, Aleisha Collinson-Streng, Tricia L. Nilles, R. Brad Jones, Vicki Tepper, Allison Agwu, Deborah Persaud
Abstract
Inherited bone marrow failure syndromes (IBMFSs) such as Fanconi Anemia (FA) and Shwachman-Diamond syndrome (SDS) feature progressive cytopenia and a risk of acute myeloid leukemia (AML). Using deep phenotypic analysis of early progenitors in FA/SDS bone marrow samples we revealed selective survival of progenitors that phenotypically resembled granulocyte-monocyte progenitors (GMP). Whole exome and targeted sequencing of GMP-like cells in leukemia-free patients revealed a higher mutation load than in healthy controls and molecular changes that are characteristic of AML: increased G>A/C>T variants, decreased A>G/T>C variants, increased trinucleotide mutations at Xp(C>T)pT and decreased mutation rates at Xp(C>T)pG sites compared to other Xp(C>T)pX sites and enrichment for Cancer signature 1 (X indicates any nucleotide). Potential pre-leukemic targets in the GMP-like cells from FA/SDS patients included SYNE1, DST, HUWE1, LRP2, NOTCH2 and TP53. Serial analysis of GMPs from a SDS patient, who progressed to leukemia revealed a gradual increase in mutational burden, enrichment of G>A/C>T signature and emergence of new clones. Interestingly, the molecular signature of marrow cells from two FA/SDS patients with leukemia was similar to that of FA/SDS patients without transformation. The predicted founding clones in SDS-AML harbored mutations in several genes including TP53, while in FA-AML the mutated genes included ARID1B and SFPQ. We described an architectural change in the hematopoietic hierarchy of FA/SDS with remarkable preservation of GMP-like populations harboring unique mutation signatures. GMP-like cells might represent a cellular reservoir for clonal evolution.
Authors
Stephanie Claudia Heidemann, Brian Bursic, Sasan Zandi, Hongbing Li, Sagi Abelson, Robert J. Klaassen, Sharon Abish, Meera S Rayar, Vicky R. Breakey, Houtan Moshiri, Santhosh Dhanraj, Richard de Borja, Adam Shlien, John E. Dick, Yigal Dror
Chronic liver disease and impaired hepatic glycogen metabolism in argininosuccinate lyase deficiency
Abstract
Background: Liver disease in urea cycle disorders (UCDs) ranges from hepatomegaly and chronic hepatocellular injury to cirrhosis and end-stage liver disease. However, the prevalence and underlying mechanisms are unclear. Methods: We estimated the prevalence of chronic hepatocellular injury in UCDs using data from a multicenter, longitudinal, natural history study. We also used ultrasound with shear wave elastography and FibroTestTM to evaluate liver stiffness and markers of fibrosis in individuals with argininosuccinate lyase deficiency (ASLD), a disorder with high prevalence of elevated serum alanine aminotransferase (ALT). To understand the human observations, we evaluated the hepatic phenotype of the AslNeo/Neo mouse model of ASLD. Results: We demonstrate a high prevalence of elevated ALT in ASLD (37%). Hyperammonemia and use of nitrogen-scavenging agents, two markers of disease severity, were significantly (p<0.001; p=0.001) associated with elevated ALT in ASLD. In addition, ultrasound with shear wave elastography and FibroTestTM revealed increased echogenicity and liver stiffness even in individuals with ASLD and normal aminotransferases. The AslNeo/Neo mice mimic the human disorder with hepatomegaly, elevated aminotransferases, and excessive hepatic glycogen noted prior to death (3-5 weeks of age). This excessive hepatic glycogen is associated with impaired hepatic glycogenolysis and decreased glycogen phosphorylase and is rescued with helper-dependent adenovirus expressing Asl using a liver specific (ApoE) promoter. Conclusions: Our results link urea cycle dysfunction and impaired hepatic glucose metabolism and identify a mouse model of liver disease in the setting of urea cycle dysfunction. Trial Registration: NCT03721367, NCT00237315 Funding: NIH, Burroughs Wellcome Fund, NUCDF, Genzyme/ACMG Foundation, CPRIT
Authors
Lindsay C. Burrage, Simran Madan, Xiaohui Li, Saima Ali, Mahmoud A. Mohammad, Bridget M. Stroup, Ming-Ming Jiang, Racel Cela, Terry Bertin, Jian Dai, Danielle Guffey, Milton Finegold, Sandesh Nagamani, Charles G. Minard, Juan Marini, Prakash Masand, Deborah Schady, Benjamin L. Shneider, Daniel H. Leung, Deeksha Bali, Brendan Lee
Abstract
Group-2 innate lymphoid cells (ILC2s) are a critical innate source of type-2 cytokines in allergic inflammation. Although ILC2s are recognized as a critical cell population in the allergic inflammation, the regulatory mechanism(s) of ILC2s are less well understood. Here, we show that Regnase-1, an immune-regulatory RNase that degrades inflammatory mRNAs, negatively regulates ILC2 function, and that IkB kinase (IKK) complex-mediated Regnase-1 degradation is essential for IL-33– and IL-25–induced ILC2 activation. ILC2s from Regnase-1AA/AA mice expressing a Regnase-1 S435A/S439A mutant resistant to IKK complex-mediated degradation, accumulated Regnase-1 protein in response to IL-33 and IL-25. IL-33– and IL-25–stimulated Regnase-1AA/AA ILC2s showed reduced cell proliferation and type-2 cytokine (IL-5, IL-9, and IL-13) production and increased cell death. In addition, Il2ra and Il1rl1, but not Il5, Il9, or Il13, mRNAs were destabilized in IL-33–stimulated Regnase-1AA/AA ILC2s. In vivo, Regnase-1AA/AA mice showed attenuated acute type-2 pulmonary inflammation induced by the instillation of IL-33, IL-25, or papain. Furthermore, the expulsion of Nippostrongylus brasiliensis was significantly delayed in Regnase-1AA/AA mice. These results demonstrate that IKK complex-mediated Regnase-1 degradation is essential for ILC2s-mediated type-2 responses both in vitro and in vivo. Therefore, controlling Regnase-1 degradation is a potential therapeutic target for ILC2-contributed allergic disorders.
Authors
Kazufumi Matsushita, Hiroki Tanaka, Koubun Yasuda, Takumi Adachi, Ayumi Fukuoka, Shoko Akasaki, Atsuhide Koida, Etsushi Kuroda, Shizuo Akira, Tomohiro Yoshimoto
Abstract
Lesch–Nyhan disease (LND) is a rare monogenic disease caused by deficiency of the salvage pathway enzyme hypoxanthine–guanine phosphoribosyltransferase (HGPRT) and is characterized by severe neuropsychiatric symptoms that currently cannot be treated. Predictive in vivo models are lacking for screening and evaluating candidate drugs because LND-associated neurological symptoms are not recapitulated in HGPRT-deficient animals. Here, we used human neural stem cells and neurons derived from induced pluripotent stem cells (iPSCs) of children affected by LND to identify neural phenotypes of interest associated with HGPRT deficiency to develop a target-agnostic-based drug screening system. We screened more than 3000 molecules and identified 6 pharmacological compounds, all possessing an adenosine moiety, that corrected HGPRT deficiency-associated neuronal phenotypes by promoting metabolism compensations in an HGPRT-independent manner. This included S-adenosylmethionine (SAM), a compound that had already been used as a compassionate approach to ease the neuropsychiatric symptoms in LND. Interestingly, these compounds compensate abnormal metabolism in a manner complementary to the gold standard allopurinol and can be provided to LND patients via simple food supplementation. This experimental paradigm can be easily adapted to other metabolic disorders affecting normal brain development and functioning in the absence of a relevant animal model.
Authors
Valentin Ruillier, Johana Tournois, Claire Boissart, Marie Lasbareilles, Gurvan Mahé, Laure Chatrousse, Michel Cailleret, Marc Peschanski, Alexandra Benchoua
Abstract
Interleukin-3 (IL3) receptor α (IL3Rα) is the alpha subunit of the ligand-specific IL3 receptor and initiates intracellular signaling in response to IL3. IL3 amplifies pro-inflammatory signaling and cytokine storm in murine sepsis models. Here we found that RNFT2 (RING finger transmembrane-domain containing protein 2, also TMEM118), a previously uncharacterized RING finger ubiquitin E3 ligase, negatively regulated IL3-dependent cellular responses through IL3Rα ubiquitination and degradation in the proteasome. In vitro, IL3 stimulation promoted IL3Rα proteasomal degradation dependent on RNFT2, and we identified IL3Rα Lysine 357 as a ubiquitin acceptor site. We determined that LPS-priming reduces RNFT2 abundance, extends IL3Rα half-life, and sensitizes cells to the effects of IL3, acting synergistically to increase pro-inflammatory signaling. In vivo, IL3 synergized with LPS to exacerbate lung inflammation in LPS and Pseudomonas aeruginosa-challenged mice; conversely, IL3 neutralization reduced LPS-induce lung injury. Further, RNFT2 over-expression reduced lung inflammation and injury, whereas Rnft2 knockdown exacerbated inflammatory responses in LPS-induced murine lung injury. Lastly, we examined RNFT2 and IL3Rα in human lung explants from patients with Cystic Fibrosis, and also showed that IL3 is elevated in mechanically-ventilated critically ill humans at risk for Acute Respiratory Distress Syndrome (ARDS). These results identify RNFT2 as a negative regulator of IL3Rα, and show a potential role for the RNFT2/IL3Rα/IL3 axis in regulating innate immune responses in the lung.
Authors
Yao Tong, Travis B. Lear, John Evankovich, Yanwen Chen, James D. Londino, Michael M. Myerburg, Yingze Zhang, Iulia D. Popescu, John F. McDyer, Bryan J. McVerry, Karina C. Lockwood, Michael J. Jurczak, Yuan Liu, Bill B. Chen
Abstract
Community-acquired pneumonia is a widespread disease with significant morbidity and mortality. Alveolar macrophages are tissue-resident lung cells that play a crucial role in innate immunity against bacteria that cause pneumonia. We hypothesized that alveolar macrophages display adaptive characteristics after resolution of bacterial pneumonia. We studied mice one to six months after self-limiting lung infections with Streptococcus pneumoniae, the most common cause of bacterial pneumonia. Alveolar macrophages, but not other myeloid cells recovered from the lung, showed long-term modifications of their surface marker phenotype. The remodeling of alveolar macrophages was: (i) long-lasting (still observed 6 months post infection), (ii) regionally localized (only observed in the affected lobe after lobar pneumonia), and (iii) associated with macrophage-dependent enhanced protection against another pneumococcal serotype. Metabolomic and transcriptomic profiling revealed that alveolar macrophages of mice that recovered from pneumonia had new baseline activities and altered responses to infection that better resembled those of adult humans. The enhanced lung protection after mild and self-limiting bacterial respiratory infections includes a profound remodeling of the alveolar macrophage pool that is long-lasting, compartmentalized, and manifest across surface receptors, metabolites, and both resting and stimulated transcriptomes.
Authors
Antoine Guillon, Emad I. Arafa, Kimberly A. Barker, Anna C. Belkina, Ian M.C. Martin, Anukul T. Shenoy, Alicia K. Wooten, Carolina Lyon De Ana, Anqi Dai, Adam Labadorf, Jaileene Hernandez-Escalante, Hans Dooms, Helene Blasco, Katrina E. Traber, Matthew R. Jones, Lee J. Quinton, Joseph P. Mizgerd
Abstract
Alcohol abuse is a major public health problem worldwide causing a wide range of preventable morbidity and mortality. In this translational study, we show that heavy drinking (HD) (≥6 standard drinks/day) is independently associated to a worse outcome of ischemic stroke patients. To study the underlying mechanisms of this deleterious effect of HD, we then performed an extensive analysis of the brain inflammatory responses of mice exposed or not to 10% alcohol before and after ischemic stroke. Inflammatory responses were analyzed at the parenchymal, perivascular and vascular levels by using transcriptomic, immunohistochemical, in vivo two-photon microscopy and molecular MRI analyses. Alcohol-exposed mice show, in the absence of any other insult, a neurovascular inflammatory priming [i.e., an abnormal inflammatory status including an increase in brain perivascular macrophages (PVM)] associated to exacerbated inflammatory responses after a secondary insult (ischemic stroke or LPS challenge). Similar to our clinical data, alcohol-exposed mice showed larger ischemic lesions. We show here that PVM are key players on this aggravating effect of alcohol, since their specific depletion blocks the alcohol-induced aggravation of ischemic lesions. This study opens new therapeutic avenues aiming at blocking alcohol-induced exacerbation of the neurovascular inflammatory responses triggered after ischemic stroke.
Authors
Antoine Drieu, Anastasia Lanquetin, Damien Levard, Martina Glavan, Francisco Campos, Aurélien Quenault, Eloïse Lemarchand, Mikael Naveau, Anne Lise Pitel, José Castillo, Denis Vivien, Marina Rubio
Abstract
ADPKD is the most common genetic cause of end stage kidney disease (ESRD). The treatment options for ADPKD are limited. We observed an upregulation in several IGF-1 pathway genes in the kidney of the Pkd1RC/RC mice. Pregnancy-associated plasma protein-A (PAPP-A), a metalloproteinase which cleaves inhibitory insulin-like growth factor binding proteins (IGFBPs), increasing the local bioactivity of IGF-1 was highly induced in the kideny of ADPKD mice. PAPP-A levels were high in cystic fluid and kidneys of humans with ADPKD. Our studies further showed the PAPP-A transcription in ADPKD is mainly regulated through the cAMP/CREB/CBP/p300 pathways. Pappa deficiency effectively inhibited the development of cysts in Pkd1RC/RC model of ADPKD. The role of PAPP-A in cystic disease appears to be regulation of the IGF-1 pathway and cellular proliferation in the kidney. Finally, preclinical studies demonstrated that treatment with monoclonal antibody that blocks the proteolytic activity of PAPP-A against IGFBP4 ameliorated ADPKD cystic disease in vivo in Pkd1RC/RC mice and ex vivo in embryonic kidneys. These data clearly indicated that the PAPP-A/IGF-1 pathway plays an important role in the growth and expansion of cysts in ADPKD. Our findings introduce a new therapeutic strategy for ADPKD that is the inhibition of PAPP-A.
Authors
Sonu Kashyap, Kyaw Zaw Hein, Claudia C.S. Chini, Jorgo Lika, Gina M. Warner, Laurie K. Bale, Vicente E. Torres, Peter C. Harris, Claus Oxvig, Cheryl A. Conover, Eduardo N. Chini
