Citations

Abstract Deep brain stimulation (DBS) of the subthalamic nucleus improves motor symptoms in patients with Parkinson’s disease. Using functional MRI, optimal DBS response networks have been characterized. However, neural activity associated with Parkinsonian symptoms is magnitudes faster than what can be resolved by this method. Although both spatial and temporal domains of these networks appear crucial, no single study has yet investigated both domains simultaneously. Here, we aimed at closing this gap by analysing electrophysiological data from a total of n = 127 hemispheres. Using subthalamic local field potentials that were recorded concurrently alongside whole-brain magnetoencephalography in a multi-centre cohort of patients who underwent subthalamic DBS for the treatment of Parkinson’s disease (n = 100 hemispheres), we analysed the DBS response network in both spatial and temporal domains. In every cortical vertex, cortico-subthalamic coupling was correlated with stimulation outcomes. This network spatially resembled functional MRI-based findings (R = 0.40, P = 0.039) and explained significant amounts of variance in clinical outcomes (βstd = 0.30, P = 0.002), whereas theta–alpha and low beta coupling did not show significant associations with DBS response (theta–alpha: βstd = −0.02, P = 0.805; low beta: βstd = −0.08, P = 0.426). The ‘optimal’ high beta coupling map was robust when subjected to various cross-validation designs (10-fold cross-validation: R = 0.29, P = 0.009; split-half design: R = 0.31, P = 0.026) and was able to predict outcomes across DBS centres [R = 0.74; P(1) = 8.9 × 10−5]. We identified a DBS response network that resembles the previously defined MRI network and operates in the high beta band. Maximal connectivity to this network was associated with optimal DBS outcomes and was able to cross-predict clinical improvements across DBS surgeons and centres.

Importance Assisted ventilation during delayed cord clamping (DCC) may improve the physiologic transition of extremely preterm infants immediately after birth. Objective To determine whether assisted ventilation during 120 seconds of DCC was associated with reduced higher-level resuscitative interventions (intubation, chest compressions, or epinephrine administration) compared with DCC for 30 to 60 seconds followed by resuscitation. Design, Setting, and Participants This was a secondary analysis of the VentFirst randomized clinical trial that was conducted from September 2, 2016, through February 21, 2023, at 12 centers in the US and Canada. Infants born at 23 weeks 0 days’ to 28 weeks 6 days’ gestational age (GA) were included. Intervention Infants randomized to the intervention received either positive-pressure ventilation or continuous positive airway pressure from 30 to 120 seconds after birth, followed by umbilical cord clamping. Those randomized to control received 30 to 60 seconds of DCC followed by assisted ventilation. Main Outcomes and Measures The main outcome was the odds of higher-level resuscitative interventions in the delivery room (DR). Intention-to-treat analyses within 2 a priori cohorts (infants breathing well and not breathing well 30 seconds after birth) used the Cochran-Mantel-Haenszel method to estimate the odds ratios (ORs) of intervention vs control. Results All 570 infants enrolled in the trial were included. Infants had a median (IQR) GA of 26.6 (25.2-27.9) weeks and 273 (47.9%) were female. A total of 271 infants (47.5%) were assessed as not breathing well 30 seconds after birth (150 intervention and 121 control), and 299 (52.5%) were assessed as breathing well 30 seconds after birth (128 intervention and 171 control). In the not-breathing-well cohort, 146 infants (53.9%) were intubated in the DR, 4 received chest compressions (2 intervention and 2 control), and 1 received epinephrine (control). Intubation was less frequent in the intervention group (71 infants [47.3%] vs 75 infants [62.0%]; OR, 0.52; 95% CI, 0.30-0.89). When adjusted by GA strata at randomization, infants in the 26 to 28 weeks’ GA stratum who were in the intervention group were less likely to be intubated in the DR (18 of 79 infants [22.8%] vs 29 of 60 infants [48.3%]; OR, 0.32; 95% CI, 0.15-0.65). However, there was no difference in intubation rates for infants in the 23 to 25 weeks’ GA stratum (53 of 71 infants [74.7%] vs 46 of 61 infants [75.4%]; OR, 0.96; 95% CI, 0.44-2.12). Among infants breathing well at 30 seconds, 74 (24.7%) were intubated in the DR, and none received compressions or epinephrine. Intubation rates were similar between intervention and control in the breathing-well cohort. Conclusions and Relevance While the VentFirst trial did not find a difference in death or intraventricular hemorrhage, this secondary analysis found that assisted ventilation during DCC was associated with less intubation in the DR, primarily among infants born at 26 to 28 weeks’ gestation who were not breathing well 30 seconds after birth. Additional studies are needed before implementing assisted ventilation during DCC in clinical practice. Trial Registration ClinicalTrials.gov Identifier: NCT02742454

Abstract Description Inflammatory bowel disease (IBD) affects between 1-3 million people in the United States, and patients present with symptoms including diarrhea, rectal bleeding, and fatigue. ST8Sia6 is a sialic acid transferase that adds terminal a2,8 disialic acids to O-linked glycoproteins, and a SNP in ST8Sia6 is associated with Crohn’s Disease. We have found that ST8Sia6 knockout (KO) and heterozygous (het) mice exhibit a 30-fold increase in small bowel immune infiltrate, along with an increased proportion of Th1 and pathogenic Th17 CD4 cells. These mice also exhibit activated gut epithelia, increased inflammatory cytokines, and increased innate cell activation, indicative of gut inflammation. Both ST8Sia6 KO and het mice exhibit increased weight loss and decreased survival when challenged with low dose dextran sodium sulfate-induced colitis. CellChat pathway analysis demonstrates enhanced TNF and IL-1 pathway activation in ST8Sia6 KO small bowel epithelium as compared to WT mice. In addition, ST8Sia6 KO small bowel epithelium produces significantly more CCL5, which may drive immune cell migration. These data demonstrate a role for ST8Sia6 in regulating gut immune homeostasis. As TNF blockade is a first line therapy for IBD patients, elucidating the role of ST8Sia6 in regulating this pathway is critical for a mechanistic understanding of IBD pathogenesis, and this may help to improve immunotherapy options for the disease. Funding Sources NIH R01CA243545 & NIH 5T32DK124190 Topic Categories Basic Autoimmunity (BA)

Abstract Description Peripheral nervous system innervation of various organs has been associated with the development and maintenance of the immune system. Various neurological insults including brain tumors induce thymic involution. Using flow cytometry and confocal microscopy, we identified a population of cells within the thymus that contained neuronal markers and morphology. Subsets expressed tyrosine hydroxylase, BIII tubulin and/or NeuN, distinguishing them from thymic epithelial cells. These cells do not express AIRE. Neuronal cell bodies and/or axonal processes were identified within the thymus. Using retrograde rabies vector neurotracers, we confirmed axonal connections and the identity of thymic neurons. To determine developmental T cell stages that support neuronal development, we evaluated RAG1/2 KO, TCRβ KO, TCRα KO, TCRγδ KO, CD4 KO, CD8 KO and OT-I and -II transgenics. RAG1/2 and TCRβ deficiency resulted in complete loss of thymic neurons. This is while TCRα KO, TCRγδ KO, CD4/8 KO and OT-II transgenics had normal thymic neuron development. Importantly, OT-I transgenics had a significant loss of neuron-like cells, indicating developing CD8 T cells pre-alpha arrangement control thymic innervation. Finally, introduction of healthy bone marrow into irradiated RAG KO mice can restore neuron development. To summarize, we describe a novel population of neuronal cells within the thymus that interact with developing thymocytes to establish optimal thymic innervation. Funding Sources R00NS117799 Topic Categories Neuroimmunology (NEUR)

Abstract Description Glioblastoma (GBM) is an aggressive brain cancer with poor survival. GBM patients have severe peripheral immunosuppression, including defective T cell responses. We showed that serum-derived factors were sufficient to inhibit T cell proliferation. This factor was nonsteroidal and larger than 100kDa. Mass-spectrometry and pathway analysis of suppressive serum implicated proteins involved in DNA response elements. We hypothesized that the suppressive factor is cell-free DNA (cfDNA). In support of this, serum levels of cfDNA are increased in glioma-bearing mice. Exposure to cfDNA from serum of glioma-bearing mice was sufficient to directly and potently inhibit T cell proliferation. Exposure to genomic DNA was not sufficient to induce proliferation defects in T cells, highlighting the unique features of cfDNA. Importantly, reducing cfDNA content using DNaseI was sufficient to partially restore proliferation capacity. We determined that the T cell proliferation defects were independent of AIM2 DNA sensing mechanisms, implicating a novel pathway of DNA sensing in T cells. Finally, to determine the origin of the cfDNA, we used methylation-seq and found that the majority of cfDNA originated from neutrophils, implicating NETosis. Together, we contend that cfDNA from neutrophils induces immunosuppressive effects in GBM. Our work highlights a potential role for targeting cfDNA, neutrophils, and/or NETs in order to reverse T cell dysfunction and improve patient outcomes in GBM. Funding Sources R00NS117799 Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract Description The live-attenuated measles virus (MeV) vaccine is one of the most efficacious vaccines ever developed and has the potential to eradicate MeV from the human population. While having been administered to millions of children over the past 60 years, the molecular mechanisms of its attenuation remain elusive. To determine these mechanisms, we have performed a comparative study of wild type (WT) and vaccine strain MeV infections in peripheral blood mononuclear cells (PBMCs) from human donors, the natural target cells of MeV. We performed in vitro growth kinetics, high-parameter spectral flow cytometry, next generation RNA-seq, and protein analyses. We found that the vaccine strain specifically activated cell intrinsic innate immunity signaling cascades causing a strong type-I interferon (IFN) signature. This resulted in 100-fold reduced titers of vaccine compared to WT virus. Surprisingly, while MeV vaccine infected B and T cells expressing the natural MeV receptor CD150 with similar efficiency as the WT virus, we found a subset of CD150-negative, CD11b+CD11c+CD123+ myeloid cells to become infected with the vaccine strain. We propose that these innate immune cells are highly specialized in pathogen sensing and prime the IFN response preventing vaccine from productive replication and generation of progeny virus in PBMCs. We currently investigate whether altered cell entry or innate immune control mechanisms are the underlying cause of attenuation. Funding Sources Supported by the German Research Foundation (DFG) Collaborative Research Center (SFB) 1021 (Project number 197785619/B12), internal funding of the German Ministry of Health, and by Mayo Clinic. Topic Categories Viral Immunology (VIR)

Abstract Description Bone marrow (BM) is the primary immune organ responsible for stem cell maintenance. Neurotropic infections elicit sequestration of T cells within the BM. Changes of the BM niche during brain viral infections are unknown. Intracranial infection with the neurotropic Theiler’s Murine Encephalomyelitis Virus (TMEV) in C57BL/6 mouse is cleared by 30 days due to generation of an antigen-specific CD8 T cell response. We determined that 1-10% of CD8 T cells present in the sternal, femoral, and cranial BM were virus antigen-specific 7 days post intracranial infection. Over 70% of these CD8 T cells were tissue resident. We determined antigen-specific CD8 T cells were generated in the BM within 4 days of infection, a timeline similar to lymph nodes. Continuous treatment with FTY720, which sequesters T cells outside of the blood, did not eliminate antigen-specific CD8 T cells in any BM compartment. CD8 T cells in the BM established durable memory populations and were reactivated upon antigen reencounter. Both acute infection and reactivation caused an increase in lineage-, Sca-1+, ckit + (LSK) cells in the BM. This LSK dysregulation was abrogated upon CD8 T cell depletion and was limited to the intracranial routes of infection. We conclude that brain viral infections induce in situ effector and memory T cell responses within the BM and cause stem cell dysregulation. Our data paves the way for crucial studies of BM resident antigen-specific CD8 T cells in health and disease. Topic Categories Viral Immunology (VIR)

Abstract Description Infants are vulnerable to infectious diseases due to the immaturity of their immune system, including a delay in producing pathogen-targeting antibodies. Maternal immunization strategies have increased in use to protect infants from disease by vertical transfer of protective pathogen-specific antibodies. Late-onset sepsis (LOS) is a substantial contributor to neonatal mortality that results from a bloodstream infection at least 72 hours after birth. The implicated pathogen is often a member of the intestinal microbiome before systemic infection, suggesting translocation from the intestine as the path to the bloodstream. We hypothesized that maternal immunization of animals prior to pregnancy could protect nursing pups in a murine model of LOS. Following maternal immunization against Enterobacteriaceae taxa implicated in sepsis, we observed significantly decreased pup mortality following an oral challenge with Escherichia coli. This protection was associated with increases in antigen-specific IgG and IgA in both the mammary tissue of vaccinated dams and stomach contents of nursing pups. Interestingly, we did not observe differences in the infant microbiota following maternal vaccination, suggesting increased pathogen-specific IgG and IgA did not perturb the developing microbiota. This work suggests maternal immunization may be useful to protect offspring from enteric pathogens, and further supports the role of human milk and human milk factors in protection from LOS. Funding Sources Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (CARB-X) Topic Categories Vaccines and Immunotherapy (VAC)

Abstract Description Innate immune sensing of viral double-stranded (ds) RNA induces the transcription of hundreds of interferon stimulated genes (ISGs) that shift the cell into an antiviral state. We have shown that measles virus (MeV) utilizes the 150 kDa isoform of adenosine deaminase acting on RNA 1 (ADAR1-p150) to prevent activation of protein kinase R (PKR), thereby subverting a type-I interferon response. Hypothesizing that cytoplasmic localization of ADAR1-p150 is required for this pro-viral activity, we generated cell lines expressing single isoforms and localization mutants of ADAR1. Based on MeV replication studies in these cells, we concluded that both nuclear and cytoplasmic ADAR1-p150 prevents PKR activation. However, only cytoplasmic but not nuclear ADAR1-p110 can efficiently prevent PKR activation. These observations suggest a bimodal activation of IFN responses. Initial sensing of viral dsRNA leads to upregulation of a subset of ISGs forming p150-specific self-RNA substrates driving PKR activation. Through ADAR editome analyses, we have identified candidate p150- and p110-specific self-RNA substrates that may be the drivers of this positive feedback loop. RNA immunoprecipitation studies to identify the specific substrates of ADAR1-p150 and PKR during MeV infection are underway to strengthen this novel model of a positive feedback loop driven by self-RNAs. Altogether, our findings shift the paradigm on the regulatory properties of self-RNA on amplifying antiviral innate immunity. Topic Categories Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)