Zhong et al. report the critical role of oncogenic KRAS/ERK/JUNB signaling in suppressing GATA6, the key regulator of differentiation in pancreatic cancers. Oncogenic KRAS-activated ERK stabilizes JUNB protein, which suppresses GATA6 transcription. Nuclear JUNB protein in pancreatic cancer xenografts was detected by immunohistochemical staining; the resulting photomicrographs were enhanced with the DeeVid AI tool. Image credit: Zheng Zhong and Xinang Cao.
Alternative splicing-triggered nonsense-mediated mRNA decay (AS-NMD) critically regulates gene expression, but the extent to which neuronal genes are regulated by AS-NMD remains understudied. Here, we identified more than 3,000 developmentally regulated AS-NMD exons in mouse and human brains, and validated them in cultured neurons. AS-NMD suppresses synaptic genes during brain development and differentially regulates more than 200 causal genes for neurodevelopmental disorders (NDDs). We detected an AS-NMD exon in GRIA2 and identified splice-switching antisense oligonucleotides that suppressed GRIA2 NMD and increased its functional isoforms. In summary, this study uncovers genes repressed by AS-NMD in the brain and nominates amenable splice-switching targets for treating dominant NDDs such as autism spectrum disorders and developmental epileptic encephalopathy.
Kaining Hu, Runwei Yang, Jiaming Qiu, Xinran Feng, Kayleigh J. LaPre, Jessica Tanouye, Yalan Yang, Xiaochang Zhang
Fibroblast growth factor receptor 1 (FGFR1) is recurrently mutated at p.N546 in neuroblastoma. We here sought to examine whether mutant FGFR1 is an oncogenic driver, a predictive biomarker, and an actionable vulnerability in this malignancy. FGFR1 mutations at p.N546 were associated with high-risk disease and rapid tumor progression, resulting in dismal outcome of these patients. Ectopic expression of FGFR1N546K induced constitutive down-stream signaling and interleukin-3-independent growth in Ba/F3 cells, indicating oncogene addicted proliferation. In FGFR1N546K;MYCN transgenic mice, neuroblastoma developed within the first days of life with fatal outcome within 3 weeks, reflecting the devastating clinical phenotypes of patients with FGFR1 mutant high-risk neuroblastoma. Treatment with FGFR inhibitors impaired proliferation and pathway activation in FGFR1N546K-expressing Ba/F3 and patient-derived FGFR1N546K mutant neuroblastoma cells, and inhibited tumor growth in FGFR1N546K;MYCN transgenic mice and in a chemotherapy-resistant patient-derived xenograft mouse model. In addition, partial regression of FGFR1N546K mutant tumor lesions occurred upon treatment with the FGFR inhibitor futibatinib and low-intensity chemotherapy in a patient with refractory neuroblastoma. Together, our data demonstrate that FGFR1N546K is a strong oncogenic driver in neuroblastoma that is associated with failure of current standard chemotherapy, and suggest potential clinical benefit of FGFR-directed therapies in FGFR1 mutant high-risk patients.
Lisa Werr, Jana Boland, Josephine Petersen, Fiorella Iglesias, Stefanie Höppner, Christoph Bartenhagen, Carolina Rosswog, Anna-Maria Hellmann, Yvonne Kahlert, Nadine Hemstedt, Nadliv Ibruli, Marcel A. Dammert, Boris Decarolis, Jan-Michael Werner, Florian Malchers, Kathrin Schramm, Olaf Witt, Klaus Hermann Beiske, Anne Gro Wesenberg Rognlien, Maria Winther Gunnes, Karin P.S. Langenberg, Jan Molenaar, Marie Bernkopf, Sabine Taschner-Mandl, Debbie Hughes, Sally L. George, Louis Chesler, Johannes H. Schulte, Giuseppe Barone, Mario Capasso, Lea F. Surrey, Rochelle Bagatell, Julien Masliah-Planchon, Gudrun Schleiermacher, Holger Grüll, Frank Westermann, Anne M. Schultheis, Reinhard Büttner, Anton G. Henssen, Angelika Eggert, Martin Peifer, Neerav N. Shukla, Thorsten Simon, Barbara Hero, H. Christian Reinhardt, Roman K. Thomas, Matthias Fischer
BACKGROUND. Susceptibility to human immunodeficiency virus type 1 (HIV-1) infection varies between individuals, but the biological determinants of acquisition risk remain poorly defined. METHODS. We conducted a case-control study nested within a high-risk cohort in Kenya. We compared the plasma extracellular RNA collected before HIV-1 acquisition with matched uninfected controls to identify immunological processes linked to infection risk. RESULTS. Individuals who later acquired HIV-1 exhibited upregulation of immune processes that facilitate viral infection, including T cell suppression, type II interferon and Th2 immune responses. In contrast, processes associated with antiviral defence and tissue repair, such as neutrophil and natural killer cell responses, type I interferon responses, wound healing, and angiogenesis, were downregulated. CONCLUSION. These findings highlight dampened antiviral immunity prior to exposure as a correlate of increased risk for subsequent HIV-1 acquisition. TRIAL NUMBERS. Not applicable. FUNDING. This work was supported by a Wellcome Trust Award (209289/Z/17/Z) and the Sub-Saharan African Network for TB/HIV Research Excellence (SANTHE) through the DELTAS Africa programme [Del-22-007], supported by the Science for Africa Foundation, Wellcome Trust, the UK Foreign, Commonwealth & Development Office, and the European Union. Additional support was provided by the Bill & Melinda Gates Foundation, Gilead Sciences Inc., Aidsfonds, and the Ragon Institute of Mass General, MIT, and Harvard. The cohort study was supported by PEPFAR through USAID. The views expressed are those of the authors.
Mwikali Kioko, Shaban Mwangi, Lynn Fwambah, Amin S. Hassan, Jason T. Blackard, Philip Bejon, Eduard J. Sanders, Thumbi Ndung'u, Eunice W. Nduati, Abdirahman I. Abdi
Obesity is accompanied by increases in free fatty acids (FFAs) in the systemic circulation, and obese patients often develop cardiac hypertrophy and diastolic dysfunction, termed obesity cardiomyopathy. Proinflammatory cytokines, including IL-6, have been implicated in the pathogenesis of the cardiac dysfunction associated with obesity cardiomyopathy. Elevation of FFAs induced by high fat diet (HFD) consumption induced diastolic dysfunction in the heart as early as after one month. HFD consumption directly stimulated IL-6 production in cardiomyocytes before local inflammation developed and induced diastolic dysfunction even in the presence of macrophage depletion with clodronate in the heart. PPARα played an essential role in mediating Il6 transcription in response to HFD consumption by forming a heterodimer with p50/RelA and binding to the NFκB element in cardiomyocytes. Local production of IL-6 in cardiomyocytes, in turn, mediated the development of diastolic cardiac dysfunction. HFD-induced diastolic dysfunction was attenuated by cardiac-specific deletion of either Ppara or Il6, as well as by interference with the PPARα-NFκB heterodimer formation by a molecular decoy. These results suggest that elevated FFAs directly upregulate Il6 through the PPARα-NFκB heterodimer in cardiomyocytes and highlight autocrine production of IL-6 as a key downstream mechanism in the initial development of diastolic dysfunction.
Shin-ichi Oka, Eun-Ah Sung, Peiyong Zhai, Kevin B. Schesing, Santosh Bhat, Adave Chin, Jiyeon Park, Yeun-Jun Chung, Akihiro Shirakabe, Takanobu Yamamoto, Yoshiyuki Ikeda, Wataru Mizushima, Shohei Ikeda, Mingming Tong, Jaemin Byun, Michinari Nakamura, Samuel I. Kim, Jamie Francisco, Dominic P. Del Re, Junichi Sadoshima
Prion diseases are a family of transmissible, neurodegenerative conditions caused by mis-folded proteins called prions. Human cerebral organoids can be infected with prions from sporadic Creutzfeldt-Jakob Disease (sCJD) brain tissue. Initial experiments indicated that the cerebral organoids may be able to differentiate biological properties of different sCJD subtypes and, if so, it would be possible to investigate the pathogenic similarities and differences. Herein, we investigated multiple infections of cerebral organoids with two sCJD subtypes, comparing hallmark features of disease as well as neuronal function and health. Our results show that while all infections produced seeding capable PrP, which increased from 90-180 days post infection, a sCJD subtype preference for protease resistant PrP deposition was observed. Both subtypes caused substantial electrophysiological dysfunction in the infected organoids, which appeared uncoupled from PrP deposition. Neuronal dysfunction was associated with changes in neurotransmitter receptors that differed between the subtypes but produced the same outcome of a shift from inhibitory toward excitatory neurotransmission. Further changes indicated shared deficits in mitochondrial dynamics, and subtype influenced alterations in intracellular signaling pathways, cytoskeletal structure, and the extracellular matrix. We conclude that cerebral organoids demonstrate both common mitochondrial deficits and sCJD subtype specific changes in neurotransmission and organoid architecture.
Katie Williams, Bradley R. Groveman, Simote T. Foliaki, Brent Race, Arielle Hay, Ryan O. Walters, Tina Thomas, Gianluigi Zanusso, James A. Carroll, Cathryn L. Haigh
Therapies targeting the glucagon-like peptide 1 (GLP-1) receptor have revolutionized the treatment of obesity and diabetes. This series of reviews, curated by Dr. Dan Drucker, describes the latest research in this fast-moving in field, from our evolving understanding of the mechanism of GLP-1 receptor signaling to the medicines’ impact on inflammation and the consequences for heart, kidney, and brain health. The reviews also explore the impact of these medicines on conditions beyond their initial indications, including cancer and neurodegenerative disease risk.
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In this episode, Dr. Seth J. Zost presents an antibody lineage from a single donor that binds the active site of influenza neuraminidase, cross-reacts with antigenically diverse viruses, and protects mice from infection...