In this issue, Liu et al. examine the neurological changes associated with hyperargininemia using an arginase-1-deficient mouse. They find that dysmyelination occurs shortly after birth but can be corrected by restoring hepatic arginase-1 via adeno-associated virus-mediated gene delivery, suggested a potential therapeutic approach that merits further study. The cover image shows restoration of basal dendritic arbors of layer V pyramidal tract neurons in an AAV-treated arginase-1-deficient mouse.
Sustained therapeutic responses from traditional and next-generation antiandrogen therapies remain elusive in clinical practice due to inherent and/or acquired resistance resulting in persistent androgen receptor (AR) activity. Antisense oligonucleotides (ASO) have the ability to block target gene expression and associated protein products and provide an alternate treatment strategy for castration-resistant prostate cancer (CRPC). We demonstrate the efficacy and therapeutic potential of this approach with a Generation-2.5 ASO targeting the mouse AR in genetically engineered models of prostate cancer. Furthermore, reciprocal feedback between AR and PI3K/AKT signaling was circumvented using a combination approach of AR-ASO therapy with the potent pan-AKT inhibitor, AZD5363. This treatment strategy effectively improved treatment responses and prolonged survival in a clinically relevant mouse model of advanced CRPC. Thus, our data provide preclinical evidence to support a combination strategy of next-generation ASOs targeting AR in combination with AKT inhibition as a potentially beneficial treatment approach for CRPC.
Marco A. De Velasco, Yurie Kura, Kazuko Sakai, Yuji Hatanaka, Barry R. Davies, Hayley Campbell, Stephanie Klein, Youngsoo Kim, A. Robert MacLeod, Koichi Sugimoto, Kazuhiro Yoshikawa, Kazuto Nishio, Hirotsugu Uemura
Dysregulated actions of bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) result in several inherited diseases, such as X-linked hypophosphatemia (XLH), and contribute substantially to the mortality in kidney failure. Mechanisms governing FGF23 production are poorly defined. We herein found that ablation of the Gq/11α–like, extralarge Gα subunit (XLαs), a product of GNAS, exhibits FGF23 deficiency and hyperphosphatemia in early postnatal mice (XLKO). FGF23 elevation in response to parathyroid hormone, a stimulator of FGF23 production via cAMP, was intact in XLKO mice, while skeletal levels of protein kinase C isoforms α and δ (PKCα and PKCδ) were diminished. XLαs ablation in osteocyte-like Ocy454 cells suppressed the levels of FGF23 mRNA, inositol 1,4,5-trisphosphate (IP3), and PKCα/PKCδ proteins. PKC activation in vivo via injecting phorbol myristate acetate (PMA) or by constitutively active Gqα-Q209L in osteocytes and osteoblasts promoted FGF23 production. Molecular studies showed that the PKC activation–induced FGF23 elevation was dependent on MAPK signaling. The baseline PKC activity was elevated in bones of Hyp mice, a model of XLH. XLαs ablation significantly, but modestly, reduced serum FGF23 and elevated serum phosphate in Hyp mice. These findings reveal a potentially hitherto-unknown mechanism of FGF23 synthesis involving a G protein–coupled IP3/PKC pathway, which may be targeted to fine-tune FGF23 levels.
Qing He, Lauren T. Shumate, Julia Matthias, Cumhur Aydin, Marc N. Wein, Jordan M. Spatz, Regina Goetz, Moosa Mohammadi, Antonius Plagge, Paola Divieti Pajevic, Murat Bastepe
It has been hypothesized that IL-1α is released from damaged cardiomyocytes following myocardial infarction (MI) and activates cardiac fibroblasts via its receptor (IL-1R1) to drive the early stages of cardiac remodeling. This study aimed to definitively test this hypothesis using cell type–specific IL-1α and IL-1R1–KO mouse models. A floxed Il1a mouse was created and used to generate a cardiomyocyte-specific IL-1α–KO (MIL1AKO) mouse line. A tamoxifen-inducible fibroblast-specific IL-1R1 hemizygous KO (FIL1R1KO) mouse line was also generated. Mice underwent experimental MI (permanent left anterior descending coronary artery ligation), and cardiac function was determined 4 weeks later by conductance pressure-volume catheter analysis. Molecular markers of remodeling were evaluated at various time points by real-time RT-PCR and histology. MIL1AKO mice showed no difference in cardiac function or molecular markers of remodeling after MI compared with littermate controls. In contrast, FIL1R1KO mice showed improved cardiac function and reduced remodeling markers after MI compared with littermate controls. In conclusion, these data highlight a key role for the IL-1R1/cardiac fibroblast signaling axis in regulating remodeling after MI and provide support for the continued development of anti–IL-1 therapies for improving cardiac function after MI. Cardiomyocyte-derived IL-1α was not an important contributor to remodeling after MI in this model.
Sumia A. Bageghni, Karen E. Hemmings, Nadira Y. Yuldasheva, Azhar Maqbool, Filomena O. Gamboa-Esteves, Neil E. Humphreys, Maj Simonsen Jackson, Christopher P. Denton, Sheila Francis, Karen E. Porter, Justin F.X. Ainscough, Emmanuel Pinteaux, Mark J. Drinkhill, Neil A. Turner
Many women with hyperandrogenemia suffer from irregular menses and infertility. However, it is unknown whether androgens directly affect reproduction. Since animal models of hyperandrogenemia-induced infertility are associated with obesity, which may impact reproductive function, we have created a lean mouse model of elevated androgen levels using implantation of low-dose 5α-dihydrotestosterone (DHT) pellets to separate the effects of elevated androgen levels from obesity. The hypothalamic-pituitary-gonadal axis controls reproduction. While we have demonstrated that androgens impair ovarian function, androgens could also disrupt neuroendocrine function at the level of brain and/or pituitary to cause infertility. To understand how elevated androgen levels might act on pituitary gonadotropes to influence reproductive function, female mice with disruption of the androgen receptor (Ar) gene specifically in pituitary gonadotropes (PitARKO) were produced. DHT-treated control mice with intact pituitary Ar (Con-DHT) exhibited disrupted estrous cyclicity and fertility with reduced pituitary responsiveness to gonadotropin-releasing hormone (GnRH) at the level of both calcium signaling and luteinizing hormone (LH) secretion. These effects were ameliorated in DHT-treated PitARKO mice. Calcium signaling controls GnRH regulation of LH vesicle exotocysis. Our data implicate upregulation of GEM (a voltage-dependent calcium channel inhibitor) in the pituitary as a potential mechanism for the pathological effects of androgens. These results demonstrate that gonadotrope AR, as an extraovarian regulator, plays an important role in reproductive pathophysiology.
Zhiqiang Wang, Mingxiao Feng, Olubusayo Awe, Yaping Ma, Mingjie Shen, Ping Xue, Rexford Ahima, Andrew Wolfe, James Segars, Sheng Wu
Although human cytomegalovirus (HCMV) is a known cause of sensorineural hearing loss in infants with congenital HCMV (cCMV) infections, mechanisms that contribute to sensorineural hearing loss (SNHL) in infants with cCMV infection are not well defined. Using a murine model of CMV infection during auditory development, we have shown that peripheral infection of newborn mice with murine CMV (MCMV) results in focal infection of the cochlea and virus-induced cochlear inflammation. Approximately 50%–60% of infected mice exhibited increased auditory brainstem response (ABR) thresholds across a range of sound frequencies. Histological analyses of the cochlea in MCMV-infected mice with elevated ABR thresholds revealed preservation of hair cell (HC) number and morphology in the organ of Corti. In contrast, the number of spiral ganglion neurons (SGN), synapses, and neurites connecting the cochlear HC and SGN nerve terminals were decreased. Decreasing cochlear inflammation by corticosteroid treatment of MCMV-infected mice resulted in preservation of SGN and improved auditory function. These findings show that virus-induced cochlear inflammation during early auditory development, rather than direct virus-mediated damage, could contribute to histopathology in the cochlea and altered auditory function without significant loss of HCs in the sensory epithelium.
Cathy Yea Won Sung, Maria C. Seleme, Shelby Payne, Stipan Jonjic, Keiko Hirose, William Britt
The mechanisms contributing to heart failure remain incompletely understood. d-dopachrome tautomerase (DDT) is a member of the macrophage migration inhibitory factor family of cytokines and is highly expressed in cardiomyocytes. This study examined the role of cardiomyocyte DDT in the setting of heart failure. Patients with advanced heart failure undergoing transplantation demonstrated decreased cardiac DDT expression. To understand the effect of loss of cardiac DDT in experimental heart failure, cardiomyocyte-specific DDT-KO (DDT-cKO) and littermate control mice underwent surgical transverse aortic constriction (TAC) to induce cardiac pressure overload. DDT-cKO mice developed more rapid cardiac contractile dysfunction, greater cardiac dilatation, and pulmonary edema after TAC. Cardiomyocytes from DDT-cKO mice after TAC had impaired contractility, calcium transients, and reduced expression of the sarcoplasmic reticulum calcium ATPase. The DDT-cKO hearts also exhibited diminished angiogenesis with reduced capillary density and lower VEGF-A expression after TAC. In pharmacological studies, recombinant DDT (rDDT) activated endothelial cell ERK1/2 and Akt signaling and had proangiogenic effects in vitro. The DDT-cKO hearts also demonstrated more interstitial fibrosis with enhanced collagen and connective tissue growth factor expression after TAC. In cardiac fibroblasts, rDDT had an antifibrotic action by inhibiting TGF-β–induced Smad-2 activation. Thus, endogenous cardiomyocyte DDT has pleiotropic actions that are protective against heart failure.
Yina Ma, Kevin N. Su, Daniel Pfau, Veena S. Rao, Xiaohong Wu, Xiaoyue Hu, Lin Leng, Xin Du, Marta Piecychna, Kenneth Bedi, Stuart G. Campbell, Anne Eichmann, Jeffrey M. Testani, Kenneth B. Margulies, Richard Bucala, Lawrence H. Young
Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal lung disease. A maladaptive epithelium due to chronic injury is a prominent feature and contributor to pathogenic cellular communication in IPF. Recent data highlight the concept of a “reprogrammed” lung epithelium as critical in the development of lung fibrosis. Extracellular vesicles (EVs) are potent mediators of cellular crosstalk, and recent evidence supports their role in lung pathologies, such as IPF. Here, we demonstrate that syndecan-1 is overexpressed by the epithelium in the lungs of patients with IPF and in murine models after bleomycin injury. Moreover, we find that syndecan-1 is a profibrotic signal that alters alveolar type II cell phenotypes by augmenting TGF-β and Wnt signaling among other profibrotic pathways. Importantly, we demonstrate that syndecan-1 controls the packaging of several antifibrotic microRNAs into EVs that have broad effects over several fibrogenic signaling networks as a mechanism of regulating epithelial plasticity and pulmonary fibrosis. Collectively, our work reveals new insight into how EVs orchestrate cellular signals that promote lung fibrosis and demonstrate the importance of syndecan-1 in coordinating these programs.
Tanyalak Parimon, Changfu Yao, David M. Habiel, Lingyin Ge, Stephanie A. Bora, Rena Brauer, Christopher M. Evans, Ting Xie, Felix Alonso-Valenteen, Lali K. Medina-Kauwe, Dianhua Jiang, Paul W. Noble, Cory M. Hogaboam, Nan Deng, Olivier Burgy, Travis J. Antes, Melanie Königshoff, Barry R. Stripp, Sina A. Gharib, Peter Chen
Dual PPARα/γ agonists that were developed to target hyperlipidemia and hyperglycemia in patients with type 2 diabetes caused cardiac dysfunction or other adverse effects. We studied the mechanisms that underlie the cardiotoxic effects of a dual PPARα/γ agonist, tesaglitazar, in wild-type and diabetic (leptin receptor–deficient, db/db) mice. Mice treated with tesaglitazar-containing chow or high-fat diet developed cardiac dysfunction despite lower plasma triglycerides and glucose levels. Expression of cardiac PPARγ coactivator 1-α (PGC1α), which promotes mitochondrial biogenesis, had the most profound reduction among various fatty acid metabolism genes. Furthermore, we observed increased acetylation of PGC1α, which suggests PGC1α inhibition and lowered sirtuin 1 (SIRT1) expression. This change was associated with lower mitochondrial abundance. Combined pharmacological activation of PPARα and PPARγ in C57BL/6 mice reproduced the reduction of PGC1α expression and mitochondrial abundance. Resveratrol-mediated SIRT1 activation attenuated tesaglitazar-induced cardiac dysfunction and corrected myocardial mitochondrial respiration in C57BL/6 and diabetic mice but not in cardiomyocyte-specific Sirt1–/– mice. Our data show that drugs that activate both PPARα and PPARγ lead to cardiac dysfunction associated with PGC1α suppression and lower mitochondrial abundance, likely due to competition between these 2 transcription factors.
Charikleia Kalliora, Ioannis D. Kyriazis, Shin-ichi Oka, Melissa J. Lieu, Yujia Yue, Estela Area-Gomez, Christine J. Pol, Ying Tian, Wataru Mizushima, Adave Chin, Diego Scerbo, P. Christian Schulze, Mete Civelek, Junichi Sadoshima, Muniswamy Madesh, Ira J. Goldberg, Konstantinos Drosatos
Steroid-refractory intestinal acute graft-versus-host disease (aGVHD) is a frequently fatal condition, with little known about mechanisms driving failed steroid responses in gut mucosa. To uncover molecular insights in steroid-refractory aGVHD, we compared gene expression profiles of rectosigmoid biopsies from patients at diagnosis of clinical stage 3–4 lower intestinal aGVHD with repeat biopsies when the patients became steroid refractory and normal controls. We also performed single-gene analyses of factors associated with tolerance (programmed cell death ligand 1 [PDL1], indoleamine 2,3-dioxygenase [IDO1], and T cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibition motif domains [TIGIT]) and found that significantly higher expression levels of these aGVHD inhibitory genes (PDL1, IDO1, TIGIT) at aGVHD onset became decreased in the steroid-refractory state. We examined genes triggered by microbial ligands to stimulate gut repair, amphiregulin (AREG) and the aryl hydrocarbon receptor (AhR), and found that both AREG and AhR gene expression levels were increased at aGVHD onset and remained elevated in steroid-refractory aGVHD. We also identified higher expression levels of metallothioneins, metal-binding enzymes induced in stress responses, and M2 macrophage genes in steroid-refractory aGVHD. We observed no differences in T cell subsets between onset and steroid-refractory aGVHD. Patients with a rapidly fatal course showed greater DNA damage and a distinct microbial signature at aGVHD onset, whereas patients with more prolonged survival exhibited a gene expression profile consistent with activation of Smoothened. Our results extend the paradigm beyond T cell–centric therapies for steroid-refractory gastrointestinal aGVHD and highlight potentially new mechanisms for therapeutic exploration.
Shernan G. Holtan, Ashraf Shabaneh, Brian C. Betts, Armin Rashidi, Margaret L. MacMillan, Celalletin Ustun, Khalid Amin, Byron P. Vaughn, Justin Howard, Alexander Khoruts, Mukta Arora, Todd E. DeFor, Darrell Johnson, Bruce R. Blazar, Daniel J. Weisdorf, Jinhua Wang
`NK cell–mediated regulation of antigen-specific T cells can contribute to and exacerbate chronic viral infection, but the protective mechanisms against NK cell–mediated attack on T cell immunity are poorly understood. Here, we show that progranulin (PGRN) can reduce NK cell cytotoxicity through reduction of NK cell expansion, granzyme B transcription, and NK cell–mediated lysis of target cells. Following infection with the lymphocytic choriomeningitis virus (LCMV), PGRN levels increased — a phenomenon dependent on the presence of macrophages and type I IFN signaling. Absence of PGRN in mice (Grn–/–) resulted in enhanced NK cell activity, increased NK cell–mediated killing of antiviral T cells, reduced antiviral T cell immunity, and increased viral burden, culminating in increased liver immunopathology. Depletion of NK cells restored antiviral immunity and alleviated pathology during infection in Grn–/– mice. In turn, PGRN treatment improved antiviral T cell immunity. Taken together, we identified PGRN as a critical factor capable of reducing NK cell–mediated attack of antiviral T cells.
Anfei Huang, Prashant V. Shinde, Jun Huang, Tina Senff, Haifeng C. Xu, Cassandra Margotta, Dieter Häussinger, Thomas E. Willnow, Jinping Zhang, Aleksandra A. Pandyra, Jörg Timm, Sascha Weggen, Karl S. Lang, Philipp A. Lang
Chemotherapy-induced peripheral neuropathy is one of the most prevalent dose-limiting toxicities of anticancer therapy. Development of effective therapies to prevent chemotherapy-induced neuropathies could be enabled by a mechanistic understanding of axonal breakdown following exposure to neuropathy-causing agents. Here, we reveal the molecular mechanisms underlying axon degeneration induced by 2 widely used chemotherapeutic agents with distinct mechanisms of action: vincristine and bortezomib. We showed previously that genetic deletion of SARM1 blocks vincristine-induced neuropathy and demonstrate here that it also prevents axon destruction following administration of bortezomib in vitro and in vivo. Using cultured neurons, we found that vincristine and bortezomib converge on a core axon degeneration program consisting of nicotinamide mononucleotide NMNAT2, SARM1, and loss of NAD+ but engage different upstream mechanisms that closely resemble Wallerian degeneration after vincristine and apoptosis after bortezomib. We could inhibit the final common axon destruction pathway by preserving axonal NAD+ levels or expressing a candidate gene therapeutic that inhibits SARM1 in vitro. We suggest that these approaches may lead to therapies for vincristine- and bortezomib-induced neuropathies and possibly other forms of peripheral neuropathy.
Stefanie Geisler, Ryan A. Doan, Galen C. Cheng, Aysel Cetinkaya-Fisgin, Shay X. Huang, Ahmet Höke, Jeffrey Milbrandt, Aaron DiAntonio
Broadly neutralizing antibodies (bNAbs) against HIV-1 are under evaluation for both prevention and therapy. HIV-1 sequence diversity observed in most HIV-infected individuals and archived variations in critical bNAb epitopes present a major challenge for the clinical application of bNAbs, as preexistent resistant viral strains can emerge, resulting in bNAb failure to control HIV. In order to identify viral resistance in patients prior to antibody therapy and to guide the selection of effective bNAb combination regimens, we developed what we believe to be a novel Bayesian machine-learning model that uses HIV-1 envelope protein sequences and foremost approximated glycan occupancy information as variables to quantitatively predict the half-maximal inhibitory concentrations (IC50) of 126 neutralizing antibodies against a variety of cross clade viruses. We then applied this model to peripheral blood mononuclear cell–derived proviral Env sequences from 25 HIV-1–infected individuals mapping the landscape of neutralization resistance within each individual’s reservoir and determined the predicted ideal bNAb combination to achieve 100% neutralization at IC50 values <1 μg/ml. Furthermore, predicted cellular viral reservoir neutralization signatures of individuals before an analytical antiretroviral treatment interruption were consistent with the measured neutralization susceptibilities of the respective plasma rebound viruses, validating our model as a potentially novel tool to facilitate the advancement of bNAbs into the clinic.
Wen-Han Yu, David Su, Julia Torabi, Christine M. Fennessey, Andrea Shiakolas, Rebecca Lynch, Tae-Wook Chun, Nicole Doria-Rose, Galit Alter, Michael S. Seaman, Brandon F. Keele, Douglas A. Lauffenburger, Boris Julg
BACKGROUND Autologous stem cell transplantation (ASCT) is the standard treatment for refractory/relapsed B cell non-Hodgkin’s lymphoma (R/R B-NHL), whereas chimeric antigen receptor T (CAR-T) therapy targeting CD19 is emerging as an alternative strategy. Here, we report a comparative analysis of the 2 strategies in a single center.METHODS We performed a prospective, single-arm study of CAR-T therapy in 29 patients with R/R B-NHL and compared the outcomes with 27 contemporaneous patients who received ASCT. NHL was diagnosed by histopathologic assessments, and the safety and efficacy of treatments were compared.RESULTS The CAR-T group exhibited better rates of complete response (CR) (48.0% vs. 20.8%, P = 0.046) and 1-year overall survival (OS) (74.4% vs. 44.5%, P = 0.044) compared with the ASCT group. Subpopulation analysis showed that patients with International Prognostic Index scores of at least 3 achieved a significantly higher objective response rate and CR rate in the CAR-T group than in the ASCT group (ORR 72.0% vs. 10.0%, P = 0.002, and CR 38.9% vs. 0%, P = 0.030, respectively). The most common severe adverse events in the CAR-T group were cytokine release syndrome, neurotoxicity, and infection compared with cytopenia, gastrointestinal toxicity, and infection in the ASCT group. Additionally, the incidence of nonhematologic severe adverse events was markedly lower in the CAR-T group than in the ASCT group (20.7% vs. 48.1%, P = 0.030).CONCLUSION CAR-T therapy exhibited superior clinical outcomes in safety and efficacy over ASCT in patients with R/R B-NHL, suggesting that CAR-T may be a recommended alternative to ASCT.TRIAL REGISTRATION ClinicalTrials.gov NCT03196830.FUNDING Funding was supplied by UniCar Therapy, National Natural Science Foundation of China (81730003), National Science and Technology Major Project (2017ZX09304021), and Science Planning Project of Suzhou (sys2018049).
Caixia Li, Ying Zhang, Changfeng Zhang, Jia Chen, Xiaoyan Lou, Xiaochen Chen, Liqing Kang, Nan Xu, Minghao Li, Jingwen Tan, Xiuli Sun, Jin Zhou, Zhen Yang, Xiangping Zong, Pu Wang, Ting Xu, Changju Qu, Haiwen Huang, Zhengming Jin, Lei Yu, Depei Wu
Deficiency of arginase is associated with hyperargininemia, and prominent features include spastic diplegia/tetraplegia, clonus, and hyperreflexia; loss of ambulation, intellectual disability and progressive neurological decline are other signs. To gain greater insight into the unique neuromotor features, we performed gene expression profiling of the motor cortex of a murine model of the disorder. Coexpression network analysis suggested an abnormality with myelination, which was supported by limited existing human data. Utilizing electron microscopy, marked dysmyelination was detected in 2-week-old homozygous Arg1-KO mice. The corticospinal tract was found to be adversely affected, supporting dysmyelination as the cause of the unique neuromotor features and implicating oligodendrocyte impairment in a deficiency of hepatic Arg1. Following neonatal hepatic gene therapy to express Arg1, the subcortical white matter, pyramidal tract, and corticospinal tract all showed a remarkable recovery in terms of myelinated axon density and ultrastructural integrity with active wrapping of axons by nearby oligodendrocyte processes. These findings support the following conclusions: arginase deficiency is a leukodystrophy affecting the brain and spinal cord while sparing the peripheral nervous system, and neonatal AAV hepatic gene therapy can rescue the defects associated with myelinated axons, strongly implicating the functional recovery of oligodendrocytes after restoration of hepatic arginase activity.
Xiao-Bo Liu, Jillian R. Haney, Gloria Cantero, Jenna R. Lambert, Marcos Otero-Garcia, Brian Truong, Andrea Gropman, Inma Cobos, Stephen D. Cederbaum, Gerald S. Lipshutz
Recent genetic examinations and multisteroid profiles have provided the basis for subclassification of aldosterone-producing adenomas (APAs). The objective of the current study was to produce a comprehensive, high-resolution mass spectrometry imaging (MSI) map of APAs in relation to morphometry, immunohistochemical profiles, mutational status, and clinical outcome. The study cohort comprised 136 patients with unilateral primary aldosteronism. Matrix-assisted laser desorption/ionization–Fourier transform–ion cyclotron resonance MSI was conducted, and metabolite profiles were analyzed with genotype/phenotype information, including digital image analysis from morphometry and IHC of steroidogenic enzymes. Distinct molecular signatures between KCNJ5- and CACNA1D-mutated APAs with significant differences of 137 metabolites, including metabolites of purine metabolism and steroidogenesis, were observed. Intratumor concentration of 18-oxocortisol and 18-hydroxycortisol were inversely correlated with the staining intensity of CYP11B1. Lower staining intensity of CYP11B1 and higher levels of 18-oxocortisol were associated with a higher probability of complete clinical success after surgery. The present study demonstrates distinct metabolomic profiles of APAs in relation to tumor genotype. In addition, we reveal an inverse correlation between cortisol derivatives and CYP11B1 and the impact of 18-oxocortisol and CYP11B1 on clinical outcome, which provides unprecedented insights into the pathophysiology, clinical features, and steroidogenesis of APAs.
Masanori Murakami, Yara Rhayem, Thomas Kunzke, Na Sun, Annette Feuchtinger, Philippe Ludwig, Tim Matthias Strom, Celso Gomez-Sanchez, Thomas Knösel, Thomas Kirchner, Tracy Ann Williams, Martin Reincke, Axel Karl Walch, Felix Beuschlein
Research shows that rats and humans on a high-fat diet (HFD) are less sensitive to satiety signals known to act via vagal afferent pathways. We hypothesize that HFD causes an upregulation of 2-pore domain potassium channels, resulting in hyperpolarization of nodose ganglia (NG) and decreased vagal response to satiety signals, which contribute to hyperphagia. We show that a 2-week HFD caused an upregulation of 2-pore domain TWIK-related spinal cord K+ (TRESK) and TWIK-related acid-sensitive K+ 1 (TASK1) channels by 330% ± 50% and 60% ± 20%, respectively, in NG. Patch-clamp studies of isolated NG neurons demonstrated a decrease in excitability. In vivo single-unit NG recordings showed that a 2-week HFD led to a 55% reduction in firing frequency in response to CCK-8 or leptin stimulation. NG electroporation with TRESK siRNA restored NG responsiveness to CCK-8 and leptin. Rats fed a 2-week HFD consumed ~40% more calories compared with controls. Silencing NG TRESK but not TASK1 channel expression in HFD-fed rats restored normal calorie consumption. In conclusion, HFD caused upregulation of TRESK channels, resulting in NG hyperpolarization and decreased vagal responsiveness to satiety signals. This finding provides a pharmacological target to prevent or treat HFD-induced hyperphagia.
Gintautas Grabauskas, Xiaoyin Wu, ShiYi Zhou, JiYao Li, Jun Gao, Chung Owyang
BACKGROUND. Aberrant expression of RNA processing genes may drive the alterative RNA profile in lower-grade gliomas (LGGs). Thus, we aimed to further stratify LGGs based on the expression of RNA processing genes. METHODS. This study included 446 LGGs from The Cancer Genome Atlas (training set) and 171 LGGs from the Chinese Glioma Genome Atlas (validation set). The least absolute shrinkage and selection operator (LASSO) Cox regression algorithm was conducted to develop a risk signature. The receiver operating characteristic curves and Kaplan-Meier curves were used to study the prognostic value of the risk signature. RESULTS. Among the tested 784 RNA processing genes, 276 were significantly correlated with the overall survival of LGGs. Further LASSO Cox regression identified a 19-gene risk signature, whose risk score was also an independent prognosis factor (P < 0.0001, multiplex Cox regression) in the validation data set. The signature had better prognostic value than the traditional factors “age,” “grade,” and “WHO 2016 classification” for 3- and 5-year survival both data sets (AUCs >85%). Importantly, the risk signature could further stratify the survival of LGGs in specific subgroups of WHO 2016 classification. Furthermore, alternative splicing events for genes such as EGFR and FGFR were found to be associated with the risk score. mRNA expression levels for genes, which participated in cell proliferation and other processes, were significantly correlated to the risk score. CONCLUSIONS. Our results highlight the role of RNA processing genes for further stratifying the survival of patients with LGGs and provide insight into the alternative splicing events underlying this role. FUNDING. The National Natural Science Foundation of China (81773208, 81402052), the Beijing Nova Program (Z16110004916082), and the National Key Research and Development Plan (2016YFC0902500).
Rui-Chao Chai, Yi-Ming Li, Ke-Nan Zhang, Yu-Zhou Chang, Yu-Qing Liu, Zheng Zhao, Zhi-Liang Wang, Yuan-Hao Chang, Guan-Zhang Li, Kuan-Yu Wang, Fan Wu, Yong-Zhi Wang
With increased life expectancy worldwide, there is an urgent need for improving preventive measures that delay the development of age-related degenerative diseases. Here, we report evidence from mouse and human studies that this goal can be achieved by maintaining optimal hydration throughout life. We demonstrate that restricting the amount of drinking water shortens mouse lifespan with no major warning signs up to 14 months of life, followed by sharp deterioration. Mechanistically, water restriction yields stable metabolism remodeling toward metabolic water production with greater food intake and energy expenditure, an elevation of markers of inflammation and coagulation, accelerated decline of neuromuscular coordination, renal glomerular injury, and the development of cardiac fibrosis. In humans, analysis of data from the Atherosclerosis Risk in Communities (ARIC) study revealed that hydration level, assessed at middle age by serum sodium concentration, is associated with markers of coagulation and inflammation and predicts the development of many age-related degenerative diseases 24 years later. The analysis estimates that improving hydration throughout life may greatly decrease the prevalence of degenerative diseases, with the most profound effect on dementia, heart failure (HF), and chronic lung disease (CLD), translating to the development of these diseases in 3 million fewer people in the United States alone.
Michele D. Allen, Danielle A. Springer, Maurice B. Burg, Manfred Boehm, Natalia I. Dmitrieva
Nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are liver manifestations of the metabolic syndrome and can progress to hepatocellular carcinoma (HCC). Loss of growth hormone (GH) signaling is reported to predispose to NAFLD and NASH through direct actions on the liver. Here, we report that aged mice lacking hepatocyte Jak2 (JAK2L), an obligate transducer of GH signaling, spontaneously develop the full spectrum of phenotypes found in patients with metabolic liver disease, beginning with insulin resistance and lipodystrophy and manifesting as NAFLD, NASH, and even HCC, independent of dietary intervention. Remarkably, insulin resistance, metabolic liver disease, and carcinogenesis are prevented in JAK2L mice via concomitant deletion of adipocyte Jak2. Further, we demonstrate that GH increases hepatic lipid burden but does so indirectly via signaling through adipocyte JAK2. Collectively, these data establish adipocytes as the mediator of GH-induced metabolic liver disease and carcinogenesis. In addition, we report what we believe to be a new spontaneous model of NAFLD, NASH, and HCC that recapitulates the natural sequelae of human insulin resistance–associated disease progression. The work presented here suggests that attention be paid to inhibition of adipocyte GH signaling as a therapeutic target of metabolic liver disease.
Kevin C. Corbit, Camella G. Wilson, Dylan Lowe, Jennifer L. Tran, Nicholas B. Vera, Michelle Clasquin, Aras N. Mattis, Ethan J. Weiss