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Abstract
Glucokinase (GK) is highly expressed in the hypothalamic paraventricular nucleus (PVN); however its role is currently unknown. We found that glucokinase in the PVN acts as part of a glucose sensing mechanism within the PVN that regulates glucose homeostasis by controlling glucagon like peptide 1 (GLP-1) release. GLP-1 is released from enteroendocrine L-cells in response to oral glucose. Here we identify a brain mechanism critical to the release of GLP-1 in response to oral glucose. We show that increasing expression of GK or injection of glucose into the PVN increases GLP-1 release in response to oral glucose. On the contrary decreasing expression of GK or injection of non-metabolisable glucose into the PVN prevents GLP-1 release. Our results demonstrate that glucosensitive GK neurones in the PVN, are critical to the response to oral glucose and subsequent release of GLP-1.
Authors
Yue Ma, Risheka Ratnasabapathy, Ivan De Backer, Chioma Izzi-Engbeaya, Marie-Sophie Nguyen-Tu, Joyceline Cuenco, Ben Jones, Christopher D. John, Brian Y. H. Lam, Guy A. Rutter, Giles Yeo, Waljit Dhillo, James Gardiner
Abstract
Capicua (CIC), a member of the high mobility group (HMG)-box superfamily of transcriptional repressors, is frequently mutated in human oligodendrogliomas. But its function in brain development and tumorigenesis remains poorly understood. Here, we report that brain-specific deletion of Cic compromises developmental transition of neuroblast to immature neurons in mouse hippocampus and compromises normal neuronal differentiation. Combined gene expression and ChIP-seq analyses identified VGF as an important CIC-repressed transcriptional surrogate involved in neuronal lineage regulation. Aberrant VGF expression promotes neural progenitor cell proliferation by suppressing their differentiation. Mechanistically, we demonstrated that CIC represses VGF expression by tethering SIN3-HDAC to form a transcriptional corepressor complex. Mass spectrometry analysis of CIC-interacting proteins further identified BRG1 containing mSWI/SNF complex whose function is necessary for transcriptional repression by CIC. Together, this study uncovers a novel regulatory pathway of CIC-dependent neuronal differentiation and may implicate these molecular mechanisms in CIC-dependent brain tumorigenesis.
Authors
Inah Hwang, Heng Pan, Jun Yao, Olivier Elemento, Hongwu Zheng, Jihye Paik
Abstract
Hydrocephalus is characterized by abnormal accumulation of cerebrospinal fluid (CSF) in the ventricular cavity. The circulation of CSF in brain ventricles is controlled by the coordinated beating of motile cilia at the surface of ependymal cells (ECs). Here we show that MT1-MMP is highly expressed in olfactory bulb, rostral migratory stream, and ventricular system. Mice deficient for Membrane type-1-MMP (MT1-MMP) develop typical phenotypes observed in hydrocephalus such as dome-shaped skull, dilated ventricles, corpus callosum agenesis and astrocyte hypertrophy during the first two weeks of postnatal development. MT1-MMP deficient mice exhibits reduced and disorganized motile cilia with the impaired maturation of ECs, leading to abnormal CSF flow. Consistent with the defects in motile cilia morphogenesis, the expressions of pro-multiciliogenic genes are significantly decreased with a concomitant hyper-activation of Notch signaling in the wall of lateral ventricles in Mmp14-/- brains. Inhibition of Notch signaling by γ-secretase inhibitor restores ciliogenesis in Mmp14-/- ECs. Taken together, these data suggest that MT1-MMP is required for ciliogenesis and ependymal cell maturation by suppressing Notch signaling during early brain development. Our findings implicate that MT1-MMP is critical for early brain development and loss of MT1-MMP activity gives rise to hydrocephalus.
Authors
Zhixin Jiang, Jin Zhou, Xin Qin, Huiling Zheng, Bo Gao, Xin-guang Liu, Guoxiang Jin, Zhongjun Zhou
Abstract
Background: Specific features of the tumor microenvironment (TME) may provide useful prognostic information. We conducted a systematic investigation of the cellular composition and prognostic landscape of TME in gastric cancer. Methods: We evaluated the prognostic significance of major stromal and immune cells within TME. We proposed a composite TME-based risk score and tested it in six independent cohorts of 1,678 patients with gene expression or immunohistochemistry measurements. Further, we devised a new patient classification system based on TME characteristics. Results: We identified natural killer cells, fibroblasts, and endothelial cells as the most robust prognostic markers. The TME risk score combining these cell types was an independent prognostic factor when adjusted for clinicopathologic variables (gene expression: HR [95% CI]: 1.42 [1.22–1.66]; immunohistochemistry: 1.34 [1.24–1.45], P<0.0001). Higher TME risk scores consistently associated with worse survival within every pathologic stage (HR range: 2.18-3.11, P<0.02) and among patients who received surgery only. The TME risk score provided additional prognostic value beyond stage, and combination of the two improved prognostication accuracy (likelihood-ratio test χ2 = 235.4 vs. 187.6, P<0.0001; net reclassification index: 23%). The TME risk score can predict the survival benefit of adjuvant chemotherapy in non-metastatic patients (stage I-III) (interaction test P<0.02). Patients were divided into four TME subtypes that demonstrated distinct genetic and molecular patterns and complemented established genomic and molecular subtypes. Conclusion: We developed and validated a TME-based risk score as an independent prognostic and predictive factor, which has the potential to guide personalized management of gastric cancer.
Authors
Bailiang Li, Yuming Jiang, Guoxin Li, George A. Fisher, Ruijiang Li
Abstract
BACKGROUND. Lower-grade gliomas (LGGs) vary widely in terms of the patient’s overall survival (OS). There is a lack of valid method that could exactly predict the survival. The effects of intratumoral immune infiltration on clinical outcome have been widely reported. Thus, we aim to develop an immune infiltration signature to predict the survival of LGG patients. METHODS. We analyzed 1216 LGGs from 5 public datasets, including 2 RNA-Seq datasets and 3 microarray datasets. Least absolute shrinkage and selection operator (LASSO) Cox regression was used to select an immune infiltration signature and build a risk score. The performance of the risk score was assessed in the training set (329 patients), internal validation set (140 patients), and 4 external validation sets (405, 118, 88, and 136 patients). RESULTS. An immune infiltration signature consisting of 20 immune metagenes was used to generate a risk score. The performance of the risk score was thoroughly verified in the training and validation sets. Additionally, we found that the risk score was positively correlated with the expression levels of TGFβ and PD-L1, which were important targets of combination immunotherapy. Furthermore, a nomogram incorporating the risk score, patient’s age, and tumor grade was developed to predict the OS, and it performed well in all the training and validation sets (C-index: 0.873, 0.881, 0.781, 0.765, 0.721, and 0.753, respectively). CONCLUSIONS. The risk score based on the immune infiltration signature has reliable prognostic and predictive value for patients with LGGs and might be a potential biomarker for the co-targeting immunotherapy. FUNDING. The National Natural Science Foundation of China (Grant No. 81472370 and 81672506), the Natural Science Foundation of Beijing (Grant No. J180005), the National High Technology Research and Development Program of China (863 Program, Grant No. 2014AA020610) and the National Basic Research Program of China (973 Program, Grant No. 2014CB542006).
Authors
Lai-Rong Song, Jian-Cong Weng, Cheng-Bei Li, Xu-Lei Huo, Huan Li, Shu-Yu Hao, Zhen Wu, Liang Wang, Da Li, Jun-Ting Zhang
Abstract
Familial Hypocalciuric Hypercalcemia (FHH) is a genetic condition associated with hypocalciuria, hypercalcemia and in some cases inappropriately high levels of circulating parathyroid hormone (PTH). FHH is associated with inactivating mutations in CaSR encoding the Ca2+ sensing receptor (CaSR), a G protein coupled receptor (GPCR) and GNA11 encoding G protein subunit alpha 11 (Gα11), implicating defective GPCR signaling as the root pathophysiology for FHH. However, the downstream mechanism by which CaSR activation inhibits PTH production/secretion is incompletely understood. Here, we show that mice lacking the transient receptor potential canonical channel 1 (TRPC1) develop chronic hypercalcemia, hypocalciuria, and elevated PTH levels mimicking human FHH. Ex vivo and in vitro studies reveal that TRPC1 serves a necessary and sufficient mediator to suppress PTH secretion from parathyroid glands (PTG) downstream of CaSR in response to high extracellular Ca2+ concentration. Gα11 physically interacts with both the N- and C-termini of TRPC1 and enhances CaSR-induced TRPC1 activity in transfected cells. These data identify TRPC1-mediated Ca2+ signaling as an essential component of the cellular apparatus controlling PTH secretion in the PTG downstream of CaSR.
Authors
Marta Onopiuk, Bonnie Eby, Vasyl Nesin, Peter Ngo, Megan Lerner, Caroline M. Gorvin, Victoria J. Stokes, Rajesh V. Thakker, Maria Luisa Brandi, Wenhan Chang, Mary Beth Humphrey, Leonidas Tsiokas, Kai Lau
Abstract
Septic cardiomyopathy is a life-threatening organ dysfunction caused by sepsis. Ribonuclease 1 (RNase 1) belongs to a group of host-defense peptides that specifically cleave extracellular RNA (eRNA). The activity of RNase1 is inhibited by ribonuclease-inhibitor 1 (RNH1). The role of RNase 1 in septic cardiomyopathy and associated cardiac apoptosis, however, is completely unknown. Here, we showed that sepsis resulted in a significant increase in RNH1 and eRNA serum levels compared to those of healthy subjects (p < 0.05). Treatment with RNase 1 resulted in a significant decrease of apoptosis, induced by the intrinsic pathway, and TNF expression in murine cardiomyocytes exposed to either necrotic cardiomyocytes or serum of septic patients for 16 h (p < 0.05). Furthermore, treatment of septic mice with RNase 1 resulted in a reduction in cardiac apoptosis, TNF expression and septic cardiomyopathy (p < 0.05). These data demonstrate that eRNA plays a crucial role in the pathophysiology of the organ (cardiac) dysfunction in sepsis and RNase and RNH1 may be new therapeutic targets/strategies to reduce the cardiac injury and dysfunction caused by sepsis.
Authors
Elisabeth Zechendorf, Caroline E O'Riordan, Lara Stiehler, Natalie Wischmeyer, Fausto Chiazza, Debora Collotta, Bernd Denecke, Sabrina Ernst, Gerhard Müller-Newen, Sina M. Coldewey, Bianka Wissuwa, Massimo Collino, Tim-Philipp Simon, Tobias Schuerholz, Christian Stoppe, Gernot Marx, Christoph Thiemermann, Lukas Martin
Abstract
Over 55,000 people in the US are diagnosed with pancreatic ductal adenocarcinoma (PDAC) yearly, and fewer than 20% of these patients survive a year beyond diagnosis. Chemotherapies are considered or used in nearly every PDAC case, but there is limited understanding of the complex signaling responses underlying resistance to these common treatments. Here, we take an unbiased approach to study protein kinase network changes following chemotherapies in patient-derived xenograft (PDX) models of PDAC to facilitate design of rational drug combinations. Proteomics profiling following chemotherapy regimens reveals that activation of JNK-JUN signaling occurs after 5-fluorouracil plus leucovorin (5-FU) and FOLFOX (5-FU plus oxaliplatin (OX)), but not after OX alone or gemcitabine. Cell and tumor growth assays with the irreversible inhibitor JNK-IN-8 and genetic manipulations demonstrate that JNK and JUN each contribute to chemoresistance and cancer cell survival after FOLFOX. Active JNK1 and JUN are specifically implicated in these effects, and synergy with JNK-IN-8 is linked to FOLFOX-mediated JUN activation, cell cycle dysregulation, and DNA damage response. This study highlights the potential for JNK-IN-8 as a biological tool and potential combination therapy with FOLFOX in PDAC and reinforces the need to tailor treatment to functional characteristics of individual tumors.
Authors
Matthew B. Lipner, Xianlu L. Peng, Chong Jin, Yi Xu, Yanzhe Gao, Michael P. East, Naim U. Rashid, Richard A. Moffitt, Silvia G. Herrera Loeza, Ashley B. Morrison, Brian T. Golitz, Cyrus Vaziri, Lee M. Graves, Gary L. Johnson, Jen Jen Yeh
Abstract
Infections due to carbapenem-resistant Klebsiella pneumoniae have emerged as a global threat due to its wide-spread antimicrobial resistance. Transplant recipients and patients with hematologic malignancies have high mortality rate suggesting host factors in susceptibility. We developed a model of pulmonary infection using ST258 C4, KPC-2 clone, which are predominant Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria, and demonstrated that Rag2-/-Il2rg-/- mice, but not wildtype C57BL/6 or Rag2-/- mice, were susceptible to this opportunistic infection. Using single-cell RNA-seq in infected Rag2-/- mice, we identified distinct clusters of Ifng+ NK cells and Il17a+, Il22+, and inducible T-cell costimulatory molecule (ICOS)+ group 3 innate lymphoid cells (ILCs) that were critical for host resistance. As solid organ transplantation is a risk factor, we generated a more clinically relevant model using FK506 in wildtype C57BL/6 mice. We further demonstrated that immunotherapy with recombinant IL-22 treatment ameliorated the ST258 pulmonary infection in both FK506 treated WT mice and Rag2-/-Il2rg-/- mice via hepatic IL-22ra1 signaling. These data support the development of host directed immunotherapy as an adjunct treatment to new antibiotics.
Authors
Naoki Iwanaga, Ivy Sandquist, Alanna Wanek, Janet E. McCombs, Kejing Song, Jay Kolls
Abstract
Abnormal wound repair has been observed in the airway epithelium of patients with chronic respiratory diseases including asthma. Therapies focusing on repairing vulnerable airways, particularly in early life, present an extremely novel treatment strategy. We report defective lower airway epithelial cell repair to strongly associate with common pre-school and school-aged wheezing phenotypes, characterised by aberrant migration patterns and reduced α5β1 integrin expression. Next generation sequencing identified the PI3K/Akt pathway as the top upstream transcriptional regulator of α5β1 integrin, where Akt activation enhanced repair and α5β1 integrin expression in primary cultures from children with wheeze. Conversely, inhibition of PI3K/Akt signaling in primary cultures from children without wheeze reduced α5β1 expression and attenuated repair. Importantly, the FDA-approved drug celecoxib, and its non-COX2-inhibiting analogue dimethyl-celecoxib, stimulated the PI3K/Akt-integrin α5β1 axis and restored airway epithelial repair in cells from children with wheeze. When compared with published clinical datasets the identified transcriptomic signature was also associated with viral-induced wheeze exacerbations highlighting the clinical potential of such therapy. Collectively, these results identify airway epithelial restitution via targeting the PI3K/Akt-integrin axis as a novel therapeutic avenue for childhood wheeze and asthma. We propose that the next step in the therapeutic development process should be a proof-of-concept clinical trial since relevant animal models to test the crucial underlying premise are unavailable.
Authors
Thomas Iosifidis, Erika N. Sutanto, Alysia Buckley, Laura A. Coleman, Erin E. Gill, Amy H. Lee, Kak-Ming Ling, Jessica Hillas, Kevin Looi, Luke W. Garratt, Kelly M. Martinovich, Nicole C. Shaw, Samuel T. Montgomery, Elizabeth Kicic-Starcevich, Yuliya V. Karpievitch, Peter Le Souef, Ingrid A. Laing, Shyan Vijayasekaran, Francis J. Lannigan, Paul J. Rigby, Robert E.W. Hancock, Darryl Knight, Stephen M. Stick, Anthony Kicic, on behalf of WAERP, on behalf of AusREC
Abstract
Increased subchondral bone angiogenesis with blood vessels breaching the tidemark into the avascular cartilage is a diagnostic feature of human osteoarthritis. However, the mechanisms that initiate subchondral bone angiogenesis remain unclear. We show that abnormally increased platelet-derived growth factor-BB (PDGF-BB) secretion by mononuclear preosteoclasts induces subchondral bone angiogenesis, contributing to osteoarthritis development. In mice after destabilization of the medial meniscus (DMM), aberrant joint subchondral bone angiogenesis developed during an early stage of osteoarthritis, before articular cartilage damage occurred. Mononuclear preosteoclasts in subchondral bone secrete excessive amounts of PDGF-BB, which activates platelet-derived growth factor receptor β (PDGFRβ) signaling in pericytes for neo-vessel formation. Selective knockout of PDGF-BB in preosteoclasts attenuates subchondral bone angiogenesis and abrogates joint degeneration and subchondral innervation induced by DMM. Transgenic mice that express PDGF-BB in preosteoclasts recapitulate pathological subchondral bone angiogenesis and develop joint degeneration and subchondral innervation spontaneously. Our study provides the first evidence that PDGF-BB derived from preosteoclasts is a key driver of pathological subchondral bone angiogenesis during osteoarthritis development and offers a new avenue for developing early treatments for this disease.
Authors
Weiping Su, Guanqiao Liu, Xiaonan Liu, Yangying Zhou, Qi Sun, Gehua Zhen, Xiao Wang, Yihe Hu, Peisong Gao, Shadpour Demehri, Xu Cao, Mei Wan
Abstract
Heart failure (HF) remains a grievous illness with poor prognosis even with optimal care. The apelin receptor (APJ) counteracts the pressor effect of angiotensin II, attenuates ischemic injury and has the potential to be a novel target to treat HF. Intravenous administration of apelin improves cardiac function acutely in HF patients. However, its short half-life restricts its use to infusion therapy. To identify a longer acting APJ agonist, we conducted a medicinal chemistry campaign leading to the discovery of potent small-molecule APJ agonists with comparable activity to apelin by mimicking the C-terminal portion of apelin-13. Acute infusion increased systolic function and reduced systemic vascular resistance in two rat models of impaired cardiac function. Similar results were obtained in an anesthetized but not a conscious canine HF model. Chronic oral dosing in a rat myocardial infarction model reduced myocardial collagen content and improved diastolic function to a similar extent as losartan, a RAS antagonist standard of care therapy, but lacked additivity with co-administration. Collectively, this work demonstrates the feasibility of developing clinical viable potent small molecule agonists that mimic the endogenous APJ ligand with more favorable drug-like properties and highlight potential limitations for APJ agonism for this indication.
Authors
Brandon Ason, Yinhong Chen, Qi Guo, Kimberly M Hoagland, Ray W. Chui, Mark Fielden, Weston Sutherland, Rhonda Chen, Ying Zhang, Shirley Mihardja, Xiaochuan Ma, Xun Li, Yaping Sun, Dongming Liu, Khanh Nguyen, Jinghong Wang, Ning Li, Sridharan Rajamani, Yusheng Qu, BaoXi Gao, Andrea Boden, Vishnu Chintalgattu, Jim R. Turk, Joyce C. Y. Chan, Liaoyuan A. Hu, Paul Dransfield, Jonathan B. Houze, Jing Man Wong, Ji Ma, Vatee Pattaropong, Murielle M. Veniant, Hugo M Vargas, Gayathri Swaminath, Aarif Khakoo
Abstract
Neutrophil extracellular traps (NETs) promote inflammation and atherosclerosis progression. NETs are increased in diabetes and impair the resolution of inflammation during wound healing. Atherosclerosis resolution, a process resembling wound healing, is also impaired in diabetes. Thus, we hypothesized that NETs impede atherosclerosis resolution in diabetes by increasing plaque inflammation. Indeed, transcriptomic profiling of plaque macrophages from NET positive and negative areas in low-density lipoprotein receptor-deficient (Ldlr-/-) mice revealed inflammasome and glycolysis pathway upregulation, indicating a heightened inflammatory phenotype. We found that NETs decline during atherosclerosis resolution, which was induced by reducing hyperlipidemia in non-diabetic mice, but they persist in diabetes, exacerbating macrophage inflammation and impairing resolution. In diabetic mice deoxyribonuclease 1 (DNase1) treatment reduced plaque NETs content and macrophage inflammation, promoting atherosclerosis resolution after lipid-lowering. Given that humans with diabetes also exhibit impaired atherosclerosis resolution with lipid-lowering, these data suggest that NETs contribute to the increased cardiovascular disease risk in this population and are a potential therapeutic target.
Authors
Tatjana Josefs, Tessa J. Barrett, Emily J. Brown, Alexandra Quezada, Xiaoyun Wu, Maud Voisin, Jaume Amengual, Edward A. Fisher
Abstract
Acinetobacter baumannii is an extremely versatile multidrug resistant pathogen with a very high mortality rate therefore, it has become crucial to understand the host response during its infection. Given the importance of mice for modelling infection and their role in pre-clinical drug development equal emphasis should be placed on the utilization of both sexes. Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced neutrophil and alveolar macrophage numbers compared to male mice. Depletion of either neutrophils or alveolar macrophages was important for bacterial clearance however, depletion of alveolar macrophages further exacerbated female susceptibility due to severe alterations in metabolic homoeostasis. Our data highlights the importance of utilizing both sexes when assessing host immune pathways.
Authors
Silvia Pires, Adeline C. Peignier, Jeremy Seto, Davida S. Smyth, Dane Parker
Abstract
C5a is a potent inflammatory mediator, which binds C5aR1 and C5aR2. Although pathogenic roles of C5a/C5aR1 axis in inflammatory disorders are well-documented, the roles for C5a/C5aR2 axis in inflammatory disorders and underlying mechanisms remain unclear. Here, we show that C5a/C5aR2 axis contributes to renal inflammation and tissue damage in a mouse model of acute pyelonephritis. Compared with WT littermates, C5ar2-/- mice had significantly reduced renal inflammation, tubular damage and renal bacterial load following bladder inoculation with uropathogenic E coli. The decrease in inflammatory responses in the kidney of C5ar2-/- mice was correlated with reduced intrarenal levels of high mobility group box 1 protein (HMGB1), NLRP3 inflammasome components, cleaved caspase-1 and IL-1β. In vitro, C5a stimulation of macrophages from C5ar1-/- mice (lacking C5aR1 but expressing C5aR2) led to significant upregulation of HMGB1 release, NLRP3/caspase-1 inflammasome activation and IL-1β secretion. Furthermore, blockade of HMGB1 significantly reduced C5a-mediated upregulation of NLRP3/caspase-1 inflammasome activation and IL-1β secretion in the macrophages, implying a HMGB1-dependent upregulation of NLRP3/caspase-1 inflammasome activation in macrophages. Our findings demonstrate a pathogenic role for C5a/C5aR2 axis in renal injury following renal infection and suggest that C5a/C5aR2 axis contributes to renal inflammation and tissue damage through up-regulation of HMGB1 and NLRP3/caspase-1 inflammasome.
Authors
Ting Zhang, Kun-yi Wu, Ning Ma, Lin-ling Wei, Malgorzata A. Garstka, Wuding Zhou, Ke Li
Abstract
A GLP-2 analogue is used in individuals with intestinal failure at risk for liver disease, yet the hepatic actions of GLP-2 are not understood. Treatment of high fat diet (HFD)-fed mice with GLP-2 did not modify development of hepatosteatosis or hepatic inflammation. In contrast, Glp2r-/- mice exhibited increased hepatic lipid accumulation, deterioration in glucose tolerance, and upregulation of biomarkers of hepatic inflammation. Both mouse and human liver expressed the canonical GLP-2R, and hepatic Glp2r expression was upregulated in mice with hepatosteatosis. Cell fractionation localized the Glp2r to hepatic stellate cells (HSC), and markers of HSC activation and fibrosis were increased in livers from Glp2r-/- mice. Moreover, GLP-2 directly modulated gene expression in isolated HSCs ex vivo. Taken together, these findings define an essential role for the GLP-2R in hepatic adaptation to nutrient excess and unveil a gut hormone-HSC axis, linking GLP-2R signaling to control of hepatic stellate cell activation.
Authors
Shai Fuchs, Bernardo Yusta, Laurie L. Baggio, Elodie M. Varin, Dianne Matthews, Daniel J. Drucker
Abstract
Acute Graft-Versus-Host Disease (aGVHD) is a T cell mediated immunological disorder and the leading cause of non-relapse mortality in patients who receive allogeneic hematopoietic cell transplants. Based on recent observations that PRMT5 and arginine methylation is upregulated in activated memory T cells, we hypothesized that PRMT5 is involved in the pathogenesis of aGVHD. Here, we show that PRMT5 expression and enzymatic activity is upregulated in activated T cells in vitro and in T cells from mice developing aGVHD after allogeneic transplant. PRMT5 expression is also upregulated in T cells of patients who developed aGVHD after allogeneic hematopoietic cell transplant compared to those who did not develop aGVHD.PRMT5 inhibition using a selective small-molecule inhibitor (C220) significantly reduces mouse and human allogeneic T cell proliferation and inflammatory IFN-γ and IL-17 cytokine production. Administration of PRMT5 small-molecule inhibitors significantly improves survival, reducing disease incidence and clinical severity in mouse models of aGVHD without adversely affecting engraftment. Importantly, we show that PRMT5 inhibition retains the beneficial graft versus leukemia (GVL) effect by maintaining cytotoxic CD8 T cell responses. Mechanistically, we show that PRMT5 inhibition potently reduces STAT-1 phosphorylation as well as transcription of pro-inflammatory genes including Interferon Stimulated Genes (ISG) and IL-17. Additionally, PRMT5 inhibition deregulates cell-cycle in activated T cells and disrupts signaling by impacting ERK1/2 phosphorylation. Thus, we have identified PRMT5 as a regulator of T cell responses and as a therapeutic target in aGVHD.
Authors
Katiri Snyder, Nina C. Zitzer, Yandi Gao, Hannah K. Choe, Natalie E. Sell, Lotus Neidemire-Colley, Anora Ignaci, Charuta Kale, Raymond D. Devine, Maria G. Abad, Maciej Pietrzak, Min Wang, Hong Lin, Yang W. Zhang, Gregory K. Behbehani, Jane E. Jackman, Ramiro Garzon, Kris Vaddi, Robert A. Baiocchi, Parvathi Ranganathan
Abstract
Background: Metabolic disorders such as type 2 diabetes have been associated with a decrease in insulin pulse frequency and amplitude. We hypothesized that the T-allele at rs7903146 in TCF7L2, previously associated with β–cell dysfunction, would be associated with changes in these insulin pulse characteristics. Methods: 29 nondiabetic subjects (age = 46 ± 2, BMI = 28 ± 1 Kg/M2) participated in this study. Of these, 16 were homozygous for the C allele at rs7903146 and 13 were homozygous for the T allele. Deconvolution of peripheral C-peptide concentrations allowed the reconstruction of portal insulin secretion over time. This data was used for subsequent analyses. Pulse orderliness was assessed by Approximate Entropy (ApEn) and the dispersion of insulin pulses was measured by a Frequency Dispersion Index (FDI) applied to a Fourier Transform of individual insulin secretion rates. Results: During fasting conditions, the CC genotype group exhibited decreased pulse disorderliness compared to the TT genotype group (1.10 ± 0.03 vs. 1.19 ± 0.04, p = 0.03). FDI decreased in response to hyperglycemia in the CC genotype group, perhaps reflecting less entrainment of insulin secretion during fasting.Conclusion: Diabetes-associated variation in TCF7L2 is associated with decreased orderliness and pulse dispersion unchanged by hyperglycemia. Quantification of ApEn and FDI could represent novel markers of β-cell health.
Authors
Marcello C. Laurenti, Chiara Dalla Man, Ron T. Varghese, James C. Andrews, Robert A. Rizza, Aleksey Matveyenko, Giuseppe De Nicolao, Claudio Cobelli, Adrian Vella
Abstract
Leptin receptor (LepRb)-expressing neurons of the nucleus tractus solitarius (NTS; LepRbNTS neurons) receive gut signals that synergize with leptin action to suppress food intake. NTS neurons that express preproglucagon (Ppg) (and which produce the food intake-suppressing PPG cleavage product, glucagon-like peptide-1 (GLP1)) represent a subpopulation of mouse LepRbNTS cells. Using Leprcre, Ppgcre, and Ppgflox mouse lines, along with designer receptors exclusively activated by designer drugs (DREADDs), we examined roles for Ppg in GLP1NTS and LepRbNTS cells for the control of food intake and energy balance. We found that the cre-dependent ablation of NTS Ppgflox early in development or in adult mice failed to alter energy balance, suggesting the importance of pathways independent of NTS GLP1 for the long-term control of food intake. Consistently, while activating GLP1NTS cells decreased food intake, LepRbNTS cells elicited larger and more durable effects. Furthermore, while the ablation of NTS Ppgflox blunted the ability of GLP1NTS neurons to suppress food intake during activation, it did not impact the suppression of food intake by LepRbNTS cells. While Ppg/GLP1-mediated neurotransmission plays a central role in the modest appetite-suppressing effects of GLP1NTS cells, additional pathways engaged by LepRbNTS cells dominate for the suppression of food intake.
Authors
Wenwen Cheng, Ermelinda Ndoka, Chelsea R. Hutch, Karen Roelofs, Andrew Mackinnon, Basma Khoury, Irwin J. Magrisso, Ki-Suk Kim, Christopher J. Rhodes, David P. Olson, Randy J. Seeley, Darleen A. Sandoval, Martin G. Myers Jr.
Abstract
Renal cysts are the defining feature of autosomal dominant polycystic kidney disease (ADPKD); however, the substantial interstitial inflammation is an often-overlooked aspect of this disorder. Recent studies suggest that immune cells in the cyst microenvironment impact ADPKD progression. Here we report that microRNAs (miRNAs) are new molecular signals in this crosstalk. We found that miR-214 and its host long non-coding RNA Dnm3os are upregulated in orthologous ADPKD mouse models and cystic kidneys from humans with ADPKD. In situ hybridization revealed that interstitial cells in the cyst microenvironment are the primary source of miR-214. While genetic deletion of miR-214 does not affect kidney development or homeostasis, surprisingly, its inhibition in Pkd2 and Pkd1 mutant mice aggravates cyst growth. Mechanistically, the pro-inflammatory TLR4/INF-γ/STAT1 pathways transactivate the miR-214 host gene. miR-214, in turn as a negative feedback loop, directly inhibits Tlr4. Accordingly, miR-214 deletion is associated with increased Tlr4 expression and enhanced peri-cystic macrophage accumulation. Thus, miR-214 upregulation is a compensatory protective response in the cyst microenvironment that restrains inflammation and cyst growth.
Authors
Ronak Lakhia, Matanel Yheskel, Andrea Flaten, Harini Ramalingam, Karam Aboudehen, Silvia Ferrè, Laurence M. Biggers, Abheepsa Mishra, Christopher Paul Chaney, Darren P. Wallace, Thomas Carroll, Peter Igarashi, Vishal Patel
