Haase et al. report that H3.3-G34 mutations in pediatric high-grade glioma impair DNA repair, increasing susceptibility to DNA damage response inhibitors and inducing cGAS/STING-mediated immune responses. Image credit: Ella Marushchenko.
KRAS is one of the most frequently activated oncogenes in human cancers. While the role of KRAS mutation in tumorigenesis and tumor maintenance has been extensively studied, the relationship between KRAS and the tumor immune microenvironment is not fully understood. Herein, we identified a novel role of KRAS in driving tumor evasion from innate immune surveillance. In lung adenocarcinoma patient samples and Kras-driven genetic mouse models of lung cancer, mutant KRAS activated the expression of cluster of differentiation 47 (CD47), an antiphagocytic signal in cancer cells, leading to decreased phagocytosis of cancer cells by macrophages. Mechanistically, mutant KRAS activated PI3K-STAT3 signaling, which restrained miR-34a expression and relieved the post-transcriptional repression of miR-34a on CD47. In three independent lung cancer patient cohorts, KRAS mutation status positively correlated with CD47 expression. Therapeutically, disruption of the KRAS-CD47 signaling axis with KRAS siRNA, the KRASG12C inhibitor AMG 510 or miR-34a mimic suppressed CD47 expression, enhanced the phagocytic capacity of macrophages and restored innate immune surveillance. Our results revealed a direct mechanistic link between active KRAS and innate immune evasion and identified CD47 as a major effector underlying KRAS-mediated immunosuppressive tumor microenvironment.
Huanhuan Hu, Rongjie Cheng, Yanbo Wang, Xiaojun Wang, Jianzhuang Wu, Yan Kong, Shoubin Zhan, Zhen Zhou, Hongyu Zhu, Ranran Yu, Gaoli Liang, Qingyan Wang, Xiaoju Zhu, Chen-Yu Zhang, Rong Yin, Chao Yan, Xi Chen
BACKGROUND. Sanfilippo type B is a mucopolysaccharidosis (MPS) with a major neuronopathic component characterized by heparan sulfate (HS) accumulation due to mutations in the NAGLU gene encoding for alfa-N-acetyl-glucosaminidase. Enzyme replacement therapy for neuronopathic MPS requires efficient enzyme delivery throughout the brain in order to normalize HS, prevent brain atrophy and potentially delay cognitive decline. METHODS. In this phase 1/2, open-label study, subjects (n=22) affected with MPS IIIB were treated with tralesinidase alfa administered intracerebroventricularly (ICV). Subjects were monitored for drug exposure, total HS and HS non-reducing end (HS-NRE) levels in both cerebrospinal fluid (CSF) and plasma, anti-drug antibody response, brain, spleen and liver volumes as measured by magnetic resonance imaging and cognitive development as measured by age-equivalent (AEq) scores. RESULTS. In the Part 1 dose escalation (30, 100, and 300 mg) phase, tralesinidase alfa 300 mg was necessary to achieve normalization of HS and HS-NRE in CSF and plasma. In Part 2, tralesinidase alfa 300 mg sustained HS and HS-NRE normalization in the CSF and stabilized cortical grey matter volume (CGMV) over 48 weeks of treatment. Resolution of hepatomegaly and reduction in spleen volume were observed in most subjects. Significant correlations were also established between change in cognitive AEq and plasma drug exposure, plasma HS-NRE level and change in CGMV. CONCLUSION. ICV administration of tralesinidase alfa effectively normalized HS and HS-NRE as a prerequisite for clinical efficacy. Peripheral drug exposure data suggests a role for the glymphatic system in altering tralesinidase alfa efficacy. TRIAL REGISTRATION. Clinicaltrials.gov: NCT02754076.
Nicole Muschol, Anja Koehn, Katharina von Cossel, Ilyas Okur, Fatih Ezgu, Paul Harmatz, Maria Jose de Castro Lopez, Maria Luz Couce, Shuan-Pei Lin, Spyros Batzios, Maureen Cleary, Martha Solano, Igor Nestrasil, Brian D. Kaufman, Adam J. Shaywitz, Stephen M. Maricich, Bernice Kuca, Joseph Kovalchin, Eric H. Zanelli
BACKGROUND. Studies assessing the efficacy of therapies for neovascular age-related macular degeneration (nvAMD) have demonstrated that aflibercept may have a longer treatment interval than its lesser-expensive alternative, bevacizumab. However, whether this benefit justifies the additional cost of aflibercept remains under debate. We have recently reported that a “treat-and-extend-pause/monitor” (TEP/M) approach can be used to successfully wean 31% of nvAMD patients off anti-VEGF therapy. Here we examine whether the choice of therapy influences the outcomes of this approach. METHODS. In this retrospective analysis, 122 eyes of 106 patients with nvAMD underwent 3 consecutive monthly injections with either aflibercept (n=70) or bevacizumab (n=52) followed by a treat-and-extend protocol in which the decision to extend the interval between treatments was based on visual acuity, clinical exam, and the presence or absence of fluid on optical coherence tomography (OCT). Eyes that remained stable 12 weeks from their prior treatment were given a 6-week trial of holding further treatment, followed by quarterly monitoring. Treatment was resumed for worsening vision, clinical exam, or OCT findings. RESULTS. At the end of one year, eyes receiving bevacizumab had similar vision but required more injections (8.7 ±0.3 vs. 7.2 ±0.3) compared to aflibercept. However, eyes treated with aflibercept were almost 3-times more likely to be weaned off treatment (43% vs. 15%) compared to eyes treated with bevacizumab at the end of one year. CONCLUSIONS. These observations expose a previously unappreciated advantage of aflibercept over bevacizumab and have important clinical implications for the selection of therapy for patients with nvAMD.
Xuan Cao, Jaron Castillo Sanchez, Tapan P. Patel, Zhiyong Yang, Chuanyu Guo, Danyal Malik, Anuoluwapo Sopeyin, Silvia Montaner, Akrit Sodhi
BACKGROUND. The kynurenine pathway (KP) has been identified as a potential mediator linking acute illness to cognitive dysfunction by generating neuroactive metabolites in response to inflammation. Delirium (acute confusion) is a common complication of acute illness and is associated with increased risk of dementia and mortality. However, the molecular mechanism underlying delirium, particularly in relation to the KP, remain elusive. METHODS. We undertook a multi-center observational study with 586 hospitalized patients (248 with delirium) and investigated associations between delirium and KP metabolites measured in cerebrospinal fluid (CSF) and serum by targeted metabolomics. We also explored associations between KP metabolites and markers of neuronal damage and one-year mortality. RESULTS. In delirium, we found concentrations of the neurotoxic metabolite quinolinic acid in CSF (CSF-QA, OR 2.26 [1.78, 2.87], p<0.001) to be increased, as well as increases in several other KP metabolites in serum and CSF. In addition, CSF-QA was associated with the neuronal damage marker neurofilament light chain (NfL, β 0.43, p<0.001) and was a strong predictor of one-year mortality (HR 4.35 [2.93, 6.45] for CSF-QA ≥ 100 nmol/L, p<0.001). The associations between CSF-QA and delirium, neuronal damage, and mortality remained highly significant following adjustment for confounders and multiple comparisons. CONCLUSION. Our data identified how systemic inflammation, neurotoxicity, and delirium are strongly linked via the KP, and should inform future delirium prevention and treatment clinical trials that target enzymes of the KP. FUNDING. Norwegian Health Association and the South-Eastern Norway Regional Health Authorities
Leiv Otto Watne, Christian Thomas Pollmann, Bjorn Erik Neerland, Else Quist-Paulsen, Nathalie Bodd Halaas, Ane-Victoria Idland, Bjørnar Hassel, Kristi Henjum, Anne-Brita Knapskog, Frede Frihagen, Johan Raeder, Aasmund Godø, Per Magne Ueland, Adrian McCann, Wender Figved, Geir Selbæk, Henrik Zetterberg, Evandro Fei Fang, Marius Myrstad, Lasse M. Giil
Repeated or prolonged, but not short-term, general anesthesia during the early postnatal period causes long-lasting impairments in memory formation in various species. The mechanisms underlying long-lasting impairment in cognitive function are poorly understood. Here we showed that repeated general anesthesia in postnatal mice induces preferential apoptosis and subsequent loss of parvalbumin-positive inhibitory interneurons in the hippocampus. Each parvalbumin interneuron controls the activity of multiple pyramidal excitatory neurons, thereby regulating neuronal circuits and memory consolidation. Preventing the loss of parvalbumin neurons by deleting a pro-apoptotic protein MAPL (Mitochondrial Anchored Protein Ligase) selectively in parvalbumin neurons rescued anesthesia-induced deficits in pyramidal cell inhibition, and hippocampus-dependent long-term memory. Conversely, partial depletion of parvalbumin neurons in neonates was sufficient to engender long-lasting memory impairment. Thus, loss of parvalbumin interneurons in postnatal mice following repeated general anesthesia critically contributes to memory deficits in adulthood.
Patricia Soriano Roque, Carolina Thörn Perez, Mehdi Hooshmandi, Calvin Wong, Mohammad Javad Eslamizade, Shilan Heshmati, Nicole Brown, Vijendra Sharma, Kevin C. Lister, Vanessa Magalie Goyon, Laura E. Neagu-Lund, Cathy Shen, Nicolas Daccache, Hiroaki Sato, Tamaki Sato, Jeffrey S. Mogil, Karim Nader, Christos G. Gkogkas, Mihaela D. Iordanova, Masha Prager-Khoutorsky, Heidi M. McBride, Jean-Claude Lacaille, Linda Wykes, Thomas Schricker, Arkady Khoutorsky
JCI This Month is a digest of the research, reviews, and other features published each month.
Aging plays a central role in many chronic diseases affecting all systems of the body. Nine hallmarks of aging have been identified: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication. This new review series on Aging closely examines how these hallmarks contribute to the initiation and progression of disease. Curated by series editor Dr. James Kirkland, topics span aging’s role in immune system function, cancer, cognitive decline and neurodegenerative disease, and metabolism. The reviews also discuss the latest developments in senotherapeutic strategies that destroy senescent cells, reverse senescence, or target specific aging hallmarks with a critical eye.