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

Focal DEPDC5 loss without disruption to cerebral cortical neuron migration recapitulates DEPDC5-related focal epilepsy

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Abstract

Focal cortical dysplasia (FCD) is a major cause of refractory epilepsy and is associated with pathogenic variants in mTOR pathway genes, including DEPDC5, the most common cause of familial focal epilepsy. The mechanisms of epileptogenesis associated with FCD and hyperactive mTOR signaling remain unclear in DEPDC5-related epilepsy. To test whether DEPDC5 loss leading to seizures require in utero cortical developmental defects or if postnatal neuronal dysfunction of mTORC1 is sufficient to drive seizures, we developed a postnatal focal cortical Depdc5 knockout mouse model. Postnatal day 0-1 Depdc5-floxed mice received unilateral motor cortex injections of either AAV-Cre-GFP or control AAV-GFP. The AAV-Cre-GFP injected hemisphere had decreased DEPDC5 levels with hyperactivation of mTOR that increased with age compared to both the contralateral hemisphere and the AAV-GFP injected mice. Cortical lamination was not disrupted by postnatal DEPDC5 loss. Pathologic hallmarks of FCDs were identified in the Depdc5 knockout hemisphere, including increased SMI-311 neurofilament staining, hypomyelination, astrogliosis, and microglial activation. Mice with postnatal cortical DEPDC5 loss exhibited lower seizure thresholds, increased focal seizures, and increased rates of seizure-induced death compared to control mice. This study demonstrates that postnatal DEPDC5 loss and subsequent mTOR hyperactivation without disruption of cortical migration is sufficient to cause epilepsy.

Authors

Karenna J. Groff, Yini Liang, Christopher Morici, Jinita Modasia, Leena Mehendale, Nishtha Gupta, Angelica D'Amore, Yongho Choe, Mustafa Q. Hameed, Alexander Rotenberg, Mustafa Sahin, Christopher J. Yuskaitis

In-utero rescue of neurological dysfunction in a mouse model of Wiedemann-Steiner syndrome

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Abstract

Wiedemann-Steiner syndrome (WDSTS) is a rare genetic cause of intellectual disability that is primarily caused by heterozygous loss of function variants in the gene encoding the histone lysine methyltransferase 2A (KMT2A). Prior studies have shown successful postnatal amelioration of disease phenotypes for Rett, Rubinstein-Taybi and Kabuki syndromes, which are related Mendelian disorders of the epigenetic machinery. To explore whether the neurological phenotype in WDSTS is treatable in-utero, we created a mouse model carrying a loss of function variant placed between two loxP sites. Kmt2a+/LSL mice demonstrated core features of WDSTS including growth retardation, craniofacial abnormalities, and hypertrichosis as well as hippocampal memory defects. The neurological phenotypes were rescued upon restoration of KMT2A in-utero following breeding to a nestin-Cre. Together, our data provided a mouse model to explore the potential therapeutic window in WDSTS. Our work suggested that WDSTS has a window of opportunity extending at least until the mid-point of in-utero development, making WDSTS an ideal candidate for future therapeutic strategies.

Authors

Tinna Reynisdottir, Kimberley J. Anderson, Katrin Möller, Stefán Pétursson, Andrew Brinn, Katheryn P. Franklin, Juan Ouyang, Asbjorg O. Snorradottir, Cathleen M. Lutz, Aamir R. Zuberi, Valerie B. DeLeon, Hans T. Bjornsson