Enhanced lipid metabolism serves as a metabolic vulnerability to polyunsaturated fatty acids in glioblastoma

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Abstract

Enhanced lipid metabolism, which involves the active import, storage, and utilization of fatty acids from the tumor microenvironment, plays a contributory role in malignant glioma transformation; thereby, serving as an important gain of function. In this work, through studies initially designed to understand and reconcile possible mechanisms underlying the anti-tumor activity of a high-fat ketogenic diet, we discovered that this phenotype of enhanced lipid metabolism observed in glioblastoma may also serve as a metabolic vulnerability to diet modification. Specifically, exogenous polyunsaturated fatty acids (PUFA) demonstrate the unique ability of short-circuiting lipid homeostasis in glioblastoma cells. This leads to lipolysis-mediated lipid droplet breakdown, an accumulation of intracellular free fatty acids, and lipid peroxidation-mediated cytotoxicity, which was potentiated when combined with radiation therapy. Leveraging this data, we formulated a PUFA-rich modified diet that does not require carbohydrate restriction, which would likely improve long-term adherence when compared to a ketogenic diet. The modified PUFA-rich diet demonstrated both anti-tumor activity and potent synergy when combined with radiation therapy in mouse glioblastoma models. Collectively, this work offers both a mechanistic understanding and a potentially translatable approach of targeting this metabolic phenotype in glioblastoma through diet modification and/or nutritional supplementation that may be readily integrated into clinical practice.

Authors

Shiva Kant, Yi Zhao, Pravin Kesarwani, Kumari Alka, Jacob F. Oyeniyi, Ghulam Mohammad, Nadia Ashrafi, Stewart F. Graham, C. Ryan Miller, Prakash Chinnaiyan

Protein-protein interaction interfering peptide rescues dysregulated NMDA receptor signaling

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Abstract

The complex and heterogeneous genetic architecture of neuropsychiatric illnesses compels us to look beyond individual risk genes for therapeutic strategies and target the interactive dynamics and convergence of their protein products. A mechanistic substrate for convergence of synaptic neuropsychiatric risk genes are protein-protein interactions (PPIs) in the NMDAR complex. NMDAR hypofunction in schizophrenia is associated with hypoactivity of Src kinase, resulting from convergent alterations in PPIs of Src with its partners. Of these, the association of Src with PSD-95, which inhibits the activity of this kinase in the NMDAR complex, is known to be increased in schizophrenia. Here, we devised a strategy to suppress the inhibition of Src by PSD-95 by employing a cell penetrating and Src activating PSD-95 inhibitory peptide (TAT-SAPIP). TAT-SAPIP enhanced synaptic NMDAR currents in Src+/- and Sdy-/- mice manifesting NMDAR hypofunction phenotypes. Chronic ICV injection of TAT-SAPIP rescued cognitive deficits in trace fear conditioning in Src +/- mice. Moreover, TAT-SAPIP enhanced Src activity in synaptoneurosomes derived from dorsolateral prefrontal cortex of 14 subjects including patients and healthy subjects. We propose blockade of the Src-PSD-95 interaction as a proof of concept for the use of interfering peptides as a therapeutic strategy to reverse NMDAR hypofunction in schizophrenia and other illnesses.

Authors

Robert E. Featherstone, Hongbin Li, Ameet S. Sengar, Karin E. Borgmann-Winter, Olya Melnychenko, Lindsey M. Crown, Ray L. Gifford, Felix Amirfathi, Anamika Banerjee, AiVi Tran, Krishna Parekh, Margaret Heller, Wenyu Zhang, Robert J. Gallop, Adam D. Marc, Pragya Komal, Michael W. Salter, Steven J. Siegel, Chang-Gyu Hahn

Transcriptional signature of induced neurons differentiates virologically suppressed people with HIV from people without HIV

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Abstract

Neurocognitive impairment is a prevalent co-morbidity in virologically suppressed people living with HIV (PLWH), yet the underlying mechanisms remain elusive and treatments lacking. We explored use of participant-derived directly induced neurons (iNs) to model neuronal biology and injury in PLWH. iNs retain age- and disease-related donor features, providing unique opportunities to reveal important aspects of neurological disorders. We obtained primary dermal fibroblasts from six virologically suppressed PLWH (range: 27-64 years, median: 53; 83% Male) and seven matched people without HIV (PWOH) (range: 27-66, median: 55; 71% Male). iNs were generated using transcription factors NGN2 and ASCL1, and validated by immunocytochemistry, single-cell-RNAseq, and electrophysiological recordings. Transcriptomic aging analyses confirmed retention of donor age-related signatures. Bulk-RNAseq identified 29 significantly differentially expressed genes between PLWH and PWOH iNs. Of these, 16 were downregulated and 13 upregulated in PLWH iNs. Protein-protein interaction network mapping indicates iNs from PLWH exhibit differences in extracellular matrix organization and synaptic transmission. IFI27 was upregulated in PLWH iNs, complementing independent post-mortem studies demonstrating elevated IFI27 expression in PLWH-derived brain tissue. FOXL2NB-FOXL2-LINC01391 expression was reduced in PLWH iNs and negatively correlated with neurocognitive impairment. Thus, we identified an iN gene signature of HIV revealing mechanisms of neurocognitive impairment in PLWH.

Authors

Philipp N. Ostermann, Youjun Wu, Scott Bowler, Samuel Martínez-Meza, Mohammad A. Siddiqui, David H. Meyer, Alberto Herrera, Brandon A. Sealy, Mega Sidharta, Kiran Ramnarine, Leslie Ann St. Bernard, Desiree Byrd, R. Jones, Masahiro Yamashita, Douglas F. Nixon, Lishomwa C. Ndhlovu, Ting Zhou, Teresa H. Evering

Cellular immune endophenotypes separating early and late-onset myasthenia gravis

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Abstract

The two main subgroups of autoimmune myasthenia gravis, a neuromuscular junction disorder associated with muscle weakness, are the early and late-onset forms, defined by onset before or after 50 years of age. Both carry acetylcholine-receptor autoantibodies, but differ in sex ratios, genetics and occurrence of disease-specific thymus inflammation. By applying multimodal techniques, including deep spectral cytometric phenotyping and single cell sequencing to peripheral blood and thymic lymphocyte samples we explored the possibility to discriminate the two forms by cellular immune phenotyping. Analyzing two independent cohorts we identified distinct immunological differences driven by three main lymphocyte populations. Lower frequencies of mucosa-associated invariant T cells and naïve CD8 T cells were observed in late-onset myasthenia, suggesting enhanced immune senescence. Further, a highly differentiated, canonical natural killer cell population was reduced in early-onset myasthenia, which was negatively correlated with the degree of thymic inflammation. Using only the frequency of these three populations, correct myasthenia subgroup assignment could be predicted with an accuracy of 90%. The NK cell population negatively associated to early-onset disease had a similar association to thymic hyperlasia, whereas the two T-cell populations point to enhanced immune senescence in late-onset myasthenia gravis. These distinct immunocellular endophenotypes for early- and late onset disease suggest differences in the immunopathogenic processes. Together with demographic factors and other disease subgroup-specific features, the frequency of the identified cell subpopulations may improve clinical classification, in turn of relevance for channeling to interventions.

Authors

Jakob Theorell, Nicolas Ruffin, Andrew Fower, Chiara Sorini, Philip Ambrose, Valentina Damato, Lahiru Handunnetthi, Isabel Leite, Sarosh R. Irani, Susanna Brauner, Adam E. Handel, Fredrik Piehl

FGF13 is not secreted from mouse neurons

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Abstract

FGF13, a noncanonical fibroblast growth factor (FGF) and member of the fibroblast growth factor homologous factor (FHF) subset, lacks a signal sequence and was previously reported to remain intracellular, where it regulates voltage-gated sodium channels (VGSCs) at least in part through direct interaction with the cytoplasmic C-terminus of VGSCs. Recent reports suggest that FGF13 is secreted and regulates neuronal VGSCs through interactions with extracellular domains of integral plasma membrane proteins, yet supportive data are limited. Using rigorous positive and negative controls, we showed that transfected FGF13 is not secreted from cultured cells in a heterologous expression system nor is endogenous FGF13 secreted from cultured neurons. Further, employing multiple unbiased screens including proximity protein proteomics, our results suggested FGF13 remains within membranes and is unavailable to interact directly with extracellular protein domains.

Authors

Mattia Malvezzi, Haiying Zhang, Patrick Towers, David C. Lyden, Steven O. Marx, Geoffrey S. Pitt

Daily locomotor activity declines with tumor growth and disease progression in glioblastoma

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Abstract

Glioblastoma (GBM) is an aggressive brain tumor that often progresses despite resection and treatment. Timely and continuous assessment of GBM progression is critical to expedite secondary surgery or enrollment in clinical trials. However, current progression detection requires costly and specialized magnetic resonance imaging (MRI), which, in the absence of new symptoms or signs, is usually scheduled every 2 to 3 months. Here, we hypothesized that changes in daily activity associate with GBM growth and disease progression. We found that wheel-running activity in GBM-bearing mice declined as tumors grew, and preceded weight loss and circadian breakdown by over a week. Temozolomide treatment in the morning, but not evening, significantly reduced tumor size and restored daily locomotion in mice. In a pilot study of six GBM patients wearing an actigraphy watch, wrist movement provided a feasible and continuous longitudinal indicator of daily activity with one-minute resolution. Following tumor resection and radiation, daily activity declined in two patients 19 and 55 days before detection of progression by MRI, but did not change for the four patients with stable disease. These results suggest that daily activity tracking using wearable devices may serve as a real-time indicator and potential monitoring tool for GBM progression and treatment efficacy.

Authors

Maria F. Gonzalez-Aponte, Sofia V. Salvatore, Anna R. Damato, Ruth G.N. Katumba, Grayson R. Talcott, Omar H. Butt, Jian L. Campian, Jingqin Luo, Joshua B. Rubin, Olivia J. Walch, Erik D. Herzog

Inhibition of the angiotensin-converting enzyme N-terminal catalytic domain prevents endogenous opioid degradation in brain tissue

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Abstract

Authors

Filip Hanak, Jessica L. Swanson, Krzysztof Felczak, Prakashkumar Dobariya, Ursula C.H. Girdwood, Kenneth E. Bernstein, Swati S. More, Patrick E. Rothwell

H3K18 lactylation potentiates microglial polarization via the TLR4 pathway in diabetes-induced cognitive impairment

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Abstract

The present study aims to explore the role and possible underlying mechanisms of histone lactylation modifications in diabetes-associated cognitive impairment (DACD). In this study, behavioral tests, Hematoxylin & Eosin (HE) staining, and immunohistochemistry were used to evaluate cognitive function and the extent of cerebral tissue injury. We quantified the levels of lactic acid and Pan-lysine lactylation (Pan Kla) in the brains of type 2 diabetes mellitus (T2DM) mice and in high glucose–treated microglia. We also identified all Kla sites in isolated microglia. Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were subsequently conducted to identify the functions and pathways that were enriched at the differentially expressed modification sites. cleavage under targets and tagmentation (CUT&Tag) technology was used to identify candidate genes that are regulated by H3K18la. Small interfering RNA (siRNA) and H3K18R mutant sequences were used to knock down crucial components in key signaling pathways to assess the effects of histone lactylation on microglial polarization. We found that lactic acid levels were significantly greater in the brains of T2DM mice and high glucose-treated microglia than in those of their corresponding controls, which increased the level of Pan-Kla. We discovered that lactate can directly stimulate an increase in H3K18la. The global landscape of the lactylome reveals information about modification sites, indicating a correlation between the upregulation of H3K18la and protein lactylation and Toll-like receptor signaling. CUT&Tag demonstrated that enhanced H3K18la directly stimulates the nuclear factor kappa-B (NF-κB) signaling pathway by increasing binding to the promoter of Toll Like Receptor 4 (TLR4), thereby promoting M1 microglial polarization. The present study demonstrated that enhanced H3K18la directly stimulates TLR4 signaling to promote M1 microglial polarization, thereby facilitating DACD phenotypes. Targeting such loop may be a potential therapeutic approach for the treatment of DACD.

Authors

Ying Yang, Fei Chen, Lulu Song, Liping Yu, Jinping Zhang, Bo Zhang

Effects of iron repletion on brain iron content, myelination, neural network activation, and cognition

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Abstract

BACKGROUND. Blood donation increases the risk of iron deficiency, but its impact on brain iron, myelination, and neurocognition remains unclear. METHODS. This ancillary study enrolled 67 iron-deficient blood donors, 19–73 years of age, participating in a double-blind, randomized trial. After donating blood, positive and negative susceptibility were measured using Quantitative Susceptibility Mapping (QSM) magnetic resonance imaging (MRI) to estimate brain iron and myelin levels, respectively. Furthermore, neurocognitive function was evaluated using the NIH Toolbox, and neural network activation patterns were assessed during neurocognitive tasks using functional MRI (fMRI). Donors were randomized to intravenous iron repletion (one-gram iron) or placebo, and outcome measures repeated approximately four months later. RESULTS. Iron repletion corrected systemic iron deficiency and led to trends toward increased whole brain iron (P=0.04) and myelination (P=0.02), with no change in the placebo group. Although overall cognitive performance did not differ significantly between groups, iron-treated participants showed improved engagement of functional neural networks (e.g., memory pattern activation during speed tasks, P<0.001). Brain region-specific changes in iron and myelin correlated with cognitive performance: iron in the putamen correlated with working memory scores (P<0.01), and thalamic myelination correlated with attention and inhibitory control (P<0.01). CONCLUSION. Iron repletion in iron-deficient blood donors may influence brain iron, myelination, and function, with region-specific changes in iron and myelination linked to distinct cognitive domains. REGISTRATION. ClinicalTrials.gov NCT02990559. FUNDING. NIH grants HL133049, HL139489, and UL1TR001873.

Authors

Eldad A. Hod, Christian Habeck, Hangwei Zhuang, Alexey Dimov, Pascal Spincemaille, Debra Kessler, Zachary C. Bitan, Yona Feit, Daysha Fliginger, Elizabeth F. Stone, David Roh, Lisa Eisler, Stephen Dashnaw, Elise Caccappolo, Donald J. McMahon, Yaakov Stern, Yi Wang, Steven L. Spitalnik, Gary M. Brittenham

Ryanodine receptor 2-mediated calcium leak is associated with increased glyoxalase I in the aging brain

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Abstract

Alzheimer’s disease (AD) is characterized by plaques and tangles, including calcium dysregulation and glycated products produced by reactive carbonyl compounds. AD brains have increased glyoxalase I (GLO1), a major scavenger of inflammatory carbonyl compounds, at early, but not later, stages of disease. Calcium dysregulation includes calcium leak from phosphorylated ryanodine receptor 2 (pS2808-RyR2), seen in aged macaques and AD mouse models, but the downstream consequences of calcium leak remain unclear. Here, we show that chronic calcium leak is associated with increased GLO1 expression and activity. In macaque, we found age-related increases in GLO1 expression in prefrontal cortex (PFC), correlating with pS2808-RyR2, and localized to dendrites and astrocytes. To examine the relationship between GLO1 and RyR2, we used S2808D-RyR2 mutant mice exhibiting chronic calcium leak through RyR2, and found increased GLO1 expression and activity in the PFC and hippocampus as early as 1-month and as late as 21-months of age, with a bell-shaped aging curve. These aged S2808D-RyR2 mice demonstrated impaired working memory. As with macaques, GLO1 was expressed in astrocytes and neurons. Proteomics data generated from S2808D-RyR2 synaptosomes confirmed GLO1 upregulation. Altogether, these data suggest potential association between GLO1 and chronic calcium leak, providing resilience in early stages of aging.

Authors

Elizabeth Woo, Dibyadeep Datta, Shveta Bathla, Hannah E. Beatty, Pinar B. Caglayan, Ashley Kristant Albizu, TuKiet T. Lam, Jean Kanyo, Mary Kate P. Joyce, Shannon N. Leslie, Stacy Uchendu, Jonathan H. DeLong, Qinyue Stacy Guan, Jiaxin Li, Efrat Abramson, Alison L. Herman, Dawson C. Cooper, Pawel Licznerski, Tamas L. Horvath, Elizabeth A. Jonas, Angus C. Nairn, Amy F.T. Arnsten, Lauren H. Sansing