Browsing by Author "Schwarz, Adam J."

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    An acetylcholine alpha7 positive allosteric modulator rescues a schizophrenia-associated brain endophenotype in the 15q13.3 microdeletion, encompassing CHRNA7
    (Elsevier, 2016-07) Gass, Natalia; Weber-Fahr, Wolfgang; Sartorius, Alexander; Becker, Robert; Didriksen, Michael; Stensbøl, Tine Bryan; Bastlund, Jesper Frank; Meyer-Lindenberg, Andreas; Schwarz, Adam J.; Department of Radiology and Imaging Sciences, IU School of Medicine
    The 15q13.3 microdeletion copy number variation is strongly associated with schizophrenia and epilepsy. The CHRNA7 gene, encoding nicotinic acetylcholine alpha 7 receptors (nAChA7Rs), is hypothesized to be one of the main genes in this deletion causing the neuropsychiatric phenotype. Here we used a recently developed 15q13.3 microdeletion mouse model to explore whether an established schizophrenia-associated connectivity phenotype is replicated in a murine model, and whether positive modulation of nAChA7 receptor might pharmacologically normalize the connectivity patterns. Resting-state fMRI data were acquired from male mice carrying a hemizygous 15q13.3 microdeletion (N=9) and from wild-type mice (N=9). To study the connectivity profile of 15q13.3 mice and test the effect of nAChA7 positive allosteric modulation, the 15q13.3 mice underwent two imaging sessions, one week apart, receiving a single intraperitoneal injection of either 15 mg/kg Lu AF58801 or saline. The control group comprised wild-type mice treated with saline. We performed seed-based functional connectivity analysis to delineate aberrant connectivity patterns associated with the deletion (15q13.3 mice (saline treatment) versus wild-type mice (saline treatment)) and their modulation by Lu AF58801 (15q13.3 mice (Lu AF58801 treatment) versus 15q13.3 mice (saline treatment)). Compared to wild-type mice, 15q13.3 mice evidenced a predominant hyperconnectivity pattern. The main effect of Lu AF58801 was a normalization of elevated functional connectivity between prefrontal and frontal, hippocampal, striatal, thalamic and auditory regions. The strongest effects were observed in brain regions expressing nAChA7Rs, namely hippocampus, cerebral cortex and thalamus. These effects may underlie the antiepileptic, pro-cognitive and auditory gating deficit-reversal effects of nAChA7R stimulation.
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    Alzheimer disease brain atrophy subtypes are associated with cognition and rate of decline
    (American Academy of Neurology, 2017-11-21) Risacher, Shannon L.; Anderson, Wesley H.; Charil, Arnaud; Castelluccio, Peter F.; Shcherbinin, Sergey; Saykin, Andrew J.; Schwarz, Adam J.; Radiology and Imaging Sciences, School of Medicine
    OBJECTIVE: To test the hypothesis that cortical and hippocampal volumes, measured in vivo from volumetric MRI (vMRI) scans, could be used to identify variant subtypes of Alzheimer disease (AD) and to prospectively predict the rate of clinical decline. METHODS: Amyloid-positive participants with AD from the Alzheimer's Disease Neuroimaging Initiative (ADNI) 1 and ADNI2 with baseline MRI scans (n = 229) and 2-year clinical follow-up (n = 100) were included. AD subtypes (hippocampal sparing [HpSpMRI], limbic predominant [LPMRI], typical AD [tADMRI]) were defined according to an algorithm analogous to one recently proposed for tau neuropathology. Relationships between baseline hippocampal volume to cortical volume ratio (HV:CTV) and clinical variables were examined by both continuous regression and categorical models. RESULTS: When participants were divided categorically, the HpSpMRI group showed significantly more AD-like hypometabolism on 18F-fluorodeoxyglucose-PET (p < 0.05) and poorer baseline executive function (p < 0.001). Other baseline clinical measures did not differ across the 3 groups. Participants with HpSpMRI also showed faster subsequent clinical decline than participants with LPMRI on the Alzheimer's Disease Assessment Scale, 13-Item Subscale (ADAS-Cog13), Mini-Mental State Examination (MMSE), and Functional Assessment Questionnaire (all p < 0.05) and tADMRI on the MMSE and Clinical Dementia Rating Sum of Boxes (CDR-SB) (both p < 0.05). Finally, a larger HV:CTV was associated with poorer baseline executive function and a faster slope of decline in CDR-SB, MMSE, and ADAS-Cog13 score (p < 0.05). These associations were driven mostly by the amount of cortical rather than hippocampal atrophy. CONCLUSIONS: AD subtypes with phenotypes consistent with those observed with tau neuropathology can be identified in vivo with vMRI. An increased HV:CTV ratio was predictive of faster clinical decline in participants with AD who were clinically indistinguishable at baseline except for a greater dysexecutive presentation.
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    Alzheimer's Disease and Small Vessel Disease Differentially Affect White Matter Microstructure
    (Wiley, 2024) Tranfa, Mario; Lorenzini, Luigi; Collij, Lyduine E.; Vállez García, David; Ingala, Silvia; Pontillo, Giuseppe; Pieperhoff, Leonard; Maranzano, Alessio; Wolz, Robin; Haller, Sven; Blennow, Kaj; Frisoni, Giovanni; Sudre, Carole H.; Chételat, Gael; Ewers, Michael; Payoux, Pierre; Waldman, Adam; Martinez-Lage, Pablo; Schwarz, Adam J.; Ritchie, Craig W.; Wardlaw, Joanna M.; Domingo Gispert, Juan; Brunetti, Arturo; Mutsaerts, Henk J. M. M.; Meije Wink, Alle; Barkhof, Frederik; Radiology and Imaging Sciences, School of Medicine
    Objective: Alzheimer's disease (AD) and cerebral small vessel disease (cSVD), the two most common causes of dementia, are characterized by white matter (WM) alterations diverging from the physiological changes occurring in healthy aging. Diffusion tensor imaging (DTI) is a valuable tool to quantify WM integrity non-invasively and identify the determinants of such alterations. Here, we investigated main effects and interactions of AD pathology, APOE-ε4, cSVD, and cardiovascular risk on spatial patterns of WM alterations in non-demented older adults. Methods: Within the prospective European Prevention of Alzheimer's Dementia study, we selected 606 participants (64.9 ± 7.2 years, 376 females) with baseline cerebrospinal fluid samples of amyloid β1-42 and p-Tau181 and MRI scans, including DTI scans. Longitudinal scans (mean follow-up time = 1.3 ± 0.5 years) were obtained in a subset (n = 223). WM integrity was assessed by extracting fractional anisotropy and mean diffusivity in relevant tracts. To identify the determinants of WM disruption, we performed a multimodel inference to identify the best linear mixed-effects model for each tract. Results: AD pathology, APOE-ε4, cSVD burden, and cardiovascular risk were all associated with WM integrity within several tracts. While limbic tracts were mainly impacted by AD pathology and APOE-ε4, commissural, associative, and projection tract integrity was more related to cSVD burden and cardiovascular risk. AD pathology and cSVD did not show any significant interaction effect. Interpretation: Our results suggest that AD pathology and cSVD exert independent and spatially different effects on WM microstructure, supporting the role of DTI in disease monitoring and suggesting independent targets for preventive medicine approaches.
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    Changes in Distribution of Severe Neurologic Involvement in US Pediatric Inpatients With COVID-19 or Multisystem Inflammatory Syndrome in Children in 2021 vs 2020
    (American Medical Association, 2023) LaRovere, Kerri L.; Poussaint, Tina Y.; Young, Cameron C.; Newhams, Margaret M.; Kucukak, Suden; Irby, Katherine; Kong, Michele; Schwartz, Stephanie P.; Walker, Tracie C.; Bembea, Melania M.; Wellnitz, Kari; Havlin, Kevin M.; Cvijanovich, Natalie Z.; Hall, Mark W.; Fitzgerald, Julie C.; Schuster, Jennifer E.; Hobbs, Charlotte V.; Halasa, Natasha B.; Singh, Aalok R.; Mack, Elizabeth H.; Bradford, Tamara T.; Gertz, Shira J.; Schwarz, Adam J.; Typpo, Katri V.; Loftis, Laura L.; Giuliano, John S., Jr.; Horwitz, Steven M.; Biagas, Katherine V.; Clouser, Katharine N.; Rowan, Courtney M.; Maddux, Aline B.; Soma, Vijaya L.; Babbitt, Christopher J.; Aguiar, Cassyanne L.; Kolmar, Amanda R.; Heidemann, Sabrina M.; Harvey, Helen; Zambrano, Laura D.; Campbell, Angela P.; Randolph, Adrienne G.; Overcoming COVID-19 Investigators; Pediatrics, School of Medicine
    Importance: In 2020 during the COVID-19 pandemic, neurologic involvement was common in children and adolescents hospitalized in the United States for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related complications. Objective: To provide an update on the spectrum of SARS-CoV-2-related neurologic involvement among children and adolescents in 2021. Design, setting, and participants: Case series investigation of patients reported to public health surveillance hospitalized with SARS-CoV-2-related illness between December 15, 2020, and December 31, 2021, in 55 US hospitals in 31 states with follow-up at hospital discharge. A total of 2253 patients were enrolled during the investigation period. Patients suspected of having multisystem inflammatory syndrome in children (MIS-C) who did not meet criteria (n = 85) were excluded. Patients (<21 years) with positive SARS-CoV-2 test results (reverse transcriptase-polymerase chain reaction and/or antibody) meeting criteria for MIS-C or acute COVID-19 were included in the analysis. Exposure: SARS-CoV-2 infection. Main outcomes and measures: Patients with neurologic involvement had acute neurologic signs, symptoms, or diseases on presentation or during hospitalization. Life-threatening neurologic involvement was adjudicated by experts based on clinical and/or neuroradiological features. Type and severity of neurologic involvement, laboratory and imaging data, vaccination status, and hospital discharge outcomes (death or survival with new neurologic deficits). Results: Of 2168 patients included (58% male; median age, 10.3 years), 1435 (66%) met criteria for MIS-C, and 476 (22%) had documented neurologic involvement. Patients with neurologic involvement vs without were older (median age, 12 vs 10 years) and more frequently had underlying neurologic disorders (107 of 476 [22%] vs 240 of 1692 [14%]). Among those with neurologic involvement, 42 (9%) developed acute SARS-CoV-2-related life-threatening conditions, including central nervous system infection/demyelination (n = 23; 15 with possible/confirmed encephalitis, 6 meningitis, 1 transverse myelitis, 1 nonhemorrhagic leukoencephalopathy), stroke (n = 11), severe encephalopathy (n = 5), acute fulminant cerebral edema (n = 2), and Guillain-Barré syndrome (n = 1). Ten of 42 (24%) survived with new neurologic deficits at discharge and 8 (19%) died. Among patients with life-threatening neurologic conditions, 15 of 16 vaccine-eligible patients (94%) were unvaccinated. Conclusions and relevance: SARS-CoV-2-related neurologic involvement persisted in US children and adolescents hospitalized for COVID-19 or MIS-C in 2021 and was again mostly transient. Central nervous system infection/demyelination accounted for a higher proportion of life-threatening conditions, and most vaccine-eligible patients were unvaccinated. COVID-19 vaccination may prevent some SARS-CoV-2-related neurologic complications and merits further study.
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    Community-Onset Bacterial Coinfection in Children Critically Ill With Severe Acute Respiratory Syndrome Coronavirus 2 Infection
    (Oxford University Press, 2023-03-06) Moffitt, Kristin L.; Nakamura, Mari M.; Young, Cameron C.; Newhams, Margaret M.; Halasa, Natasha B.; Reed, J. Nelson; Fitzgerald, Julie C.; Spinella, Philip C.; Soma, Vijaya L.; Walker, Tracie C.; Loftis, Laura L.; Maddux, Aline B.; Kong, Michele; Rowan, Courtney M.; Hobbs, Charlotte V.; Schuster, Jennifer E.; Riggs, Becky J.; McLaughlin, Gwenn E.; Michelson, Kelly N.; Hall, Mark W.; Babbitt, Christopher J.; Cvijanovich, Natalie Z.; Zinter, Matt S.; Maamari, Mia; Schwarz, Adam J.; Singh, Aalok R.; Flori, Heidi R.; Gertz, Shira J.; Staat, Mary A.; Giuliano, John S., Jr.; Hymes, Saul R.; Clouser, Katharine N.; McGuire, John; Carroll, Christopher L.; Thomas, Neal J.; Levy, Emily R.; Randolph, Adrienne G.; Pediatrics, School of Medicine
    Background: Community-onset bacterial coinfection in adults hospitalized with coronavirus disease 2019 (COVID-19) is reportedly uncommon, though empiric antibiotic use has been high. However, data regarding empiric antibiotic use and bacterial coinfection in children with critical illness from COVID-19 are scarce. Methods: We evaluated children and adolescents aged <19 years admitted to a pediatric intensive care or high-acuity unit for COVID-19 between March and December 2020. Based on qualifying microbiology results from the first 3 days of admission, we adjudicated whether patients had community-onset bacterial coinfection. We compared demographic and clinical characteristics of those who did and did not (1) receive antibiotics and (2) have bacterial coinfection early in admission. Using Poisson regression models, we assessed factors associated with these outcomes. Results: Of the 532 patients, 63.3% received empiric antibiotics, but only 7.1% had bacterial coinfection, and only 3.0% had respiratory bacterial coinfection. In multivariable analyses, empiric antibiotics were more likely to be prescribed for immunocompromised patients (adjusted relative risk [aRR], 1.34 [95% confidence interval {CI}, 1.01-1.79]), those requiring any respiratory support except mechanical ventilation (aRR, 1.41 [95% CI, 1.05-1.90]), or those requiring invasive mechanical ventilation (aRR, 1.83 [95% CI, 1.36-2.47]) (compared with no respiratory support). The presence of a pulmonary comorbidity other than asthma (aRR, 2.31 [95% CI, 1.15-4.62]) was associated with bacterial coinfection. Conclusions: Community-onset bacterial coinfection in children with critical COVID-19 is infrequent, but empiric antibiotics are commonly prescribed. These findings inform antimicrobial use and support rapid de-escalation when evaluation shows coinfection is unlikely.
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    Criterion Validation of Tau PET Staging Schemes in Relation to Cognitive Outcomes
    (IOS Press, 2023) Hammers, Dustin B.; Lin, Joshua H.; Polsinelli, Angelina J.; Logan, Paige E.; Risacher, Shannon L.; Schwarz, Adam J.; Apostolova, Liana G.; Alzheimer’s Disease Neuroimaging Initiative; Neurology, School of Medicine
    Background: Utilization of NIA-AA Research Framework requires dichotomization of tau pathology. However, due to the novelty of tau-PET imaging, there is no consensus on methods to categorize scans into "positive" or "negative" (T+ or T-). In response, some tau topographical pathologic staging schemes have been developed. Objective: The aim of the current study is to establish criterion validity to support these recently-developed staging schemes. Methods: Tau-PET data from 465 participants from the Alzheimer's Disease Neuroimaging Initiative (aged 55 to 90) were classified as T+ or T- using decision rules for the Temporal-Occipital Classification (TOC), Simplified TOC (STOC), and Lobar Classification (LC) tau pathologic schemes of Schwarz, and Chen staging scheme. Subsequent dichotomization was analyzed in comparison to memory and learning slope performances, and diagnostic accuracy using actuarial diagnostic methods. Results: Tau positivity was associated with worse cognitive performance across all staging schemes. Cognitive measures were nearly all categorized as having "fair" sensitivity at classifying tau status using TOC, STOC, and LC schemes. Results were comparable between Schwarz schemes, though ease of use and better data fit preferred the STOC and LC schemes. While some evidence was supportive for Chen's scheme, validity lagged behind others-likely due to elevated false positive rates. Conclusions: Tau-PET staging schemes appear to be valuable for Alzheimer's disease diagnosis, tracking, and screening for clinical trials. Their validation provides support as options for tau pathologic dichotomization, as necessary for use of NIA-AA Research Framework. Future research should consider other staging schemes and validation with other outcome benchmarks.
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    Derivation, validation, and transcriptomic assessment of pediatric septic shock phenotypes identified through latent profile analyses: Results from a prospective multi-center observational cohort
    (Research Square, 2023-12-06) Atreya, Mihir R.; Huang, Min; Moore, Andrew R.; Zheng, Hong; Hasin-Brumshtein, Yehudit; Fitzgerald, Julie C.; Weiss, Scott L.; Cvijanovich, Natalie Z.; Bigham, Michael T.; Jain, Parag N.; Schwarz, Adam J.; Lutfi, Riad; Nowak, Jeffrey; Thomas, Neal J.; Quasney, Michael; Dahmer, Mary K.; Baines, Torrey; Haileselassie, Bereketeab; Lautz, Andrew J.; Stanski, Natalja L.; Standage, Stephen W.; Kaplan, Jennifer M.; Zingarelli, Basilia; Sweeney, Timothy E.; Khatri, Purvesh; Sanchez-Pinto, L. Nelson; Kamaleswaran, Rishikesan; Pediatrics, School of Medicine
    Background: Sepsis poses a grave threat, especially among children, but treatments are limited due to clinical and biological heterogeneity among patients. Thus, there is an urgent need for precise subclassification of patients to guide therapeutic interventions. Methods: We used clinical, laboratory, and biomarker data from a prospective multi-center pediatric septic shock cohort to derive phenotypes using latent profile analyses. Thereafter, we trained a support vector machine model to assign phenotypes in a hold-out validation set. We tested interactions between phenotypes and common sepsis therapies on clinical outcomes and conducted transcriptomic analyses to better understand the phenotype-specific biology. Finally, we compared whether newly identified phenotypes overlapped with established gene-expression endotypes and tested the utility of an integrated subclassification scheme. Findings: Among 1,071 patients included, we identified two phenotypes which we named 'inflamed' (19.5%) and an 'uninflamed' phenotype (80.5%). The 'inflamed' phenotype had an over 4-fold risk of 28-day mortality relative to those 'uninflamed'. Transcriptomic analysis revealed overexpression of genes implicated in the innate immune response and suggested an overabundance of developing neutrophils, pro-T/NK cells, and NK cells among those 'inflamed'. There was no significant overlap between endotypes and phenotypes. However, an integrated subclassification scheme demonstrated varying survival probabilities when comparing endophenotypes. Interpretation: Our research underscores the reproducibility of latent profile analyses to identify clinical and biologically informative pediatric septic shock phenotypes with high prognostic relevance. Pending validation, an integrated subclassification scheme, reflective of the different facets of the host response, holds promise to inform targeted intervention among those critically ill.
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    A Description of COVID-19-Directed Therapy in Children Admitted to US Intensive Care Units 2020
    (Oxford University Press, 2022) Schuster, Jennifer E.; Halasa, Natasha B.; Nakamura, Mari; Levy, Emily R.; Fitzgerald, Julie C.; Young, Cameron C.; Newhams, Margaret M.; Bourgeois, Florence; Staat, Mary A.; Hobbs, Charlotte V.; Dapul, Heda; Feldstein, Leora R.; Jackson, Ashley M.; Mack, Elizabeth H.; Walker, Tracie C.; Maddux, Aline B.; Spinella, Philip C.; Loftis, Laura L.; Kong, Michele; Rowan, Courtney M.; Bembea, Melania M.; McLaughlin, Gwenn E.; Hall, Mark W.; Babbitt, Christopher J.; Maamari, Mia; Zinter, Matt S.; Cvijanovich, Natalie Z.; Michelson, Kelly N.; Gertz, Shira J.; Carroll, Christopher L.; Thomas, Neal J.; Giuliano, John S., Jr.; Singh, Aalok R.; Hymes, Saul R.; Schwarz, Adam J.; McGuire, John K.; Nofziger, Ryan A.; Flori, Heidi R.; Clouser, Katharine N.; Wellnitz, Kari; Cullimore, Melissa L.; Hume, Janet R.; Patel, Manish; Randolph, Adrienne G.; Overcoming COVID-19 Investigators; Pediatrics, School of Medicine
    Background: It is unclear how acute coronavirus disease 2019 (COVID-19)-directed therapies are used in children with life-threatening COVID-19 in US hospitals. We described characteristics of children hospitalized in the intensive care unit or step-down unit (ICU/SDU) who received COVID-19-directed therapies and the specific therapies administered. Methods: Between March 15, 2020 and December 27, 2020, children <18 years of age in the ICU/SDU with acute COVID-19 at 48 pediatric hospitals in the United States were identified. Demographics, laboratory values, and clinical course were compared in children who did and did not receive COVID-19-directed therapies. Trends in COVID-19-directed therapies over time were evaluated. Results: Of 424 children in the ICU/SDU, 235 (55%) received COVID-19-directed therapies. Children who received COVID-19-directed therapies were older than those who did not receive COVID-19-directed therapies (13.3 [5.6-16.2] vs 9.8 [0.65-15.9] years), more had underlying medical conditions (188 [80%] vs 104 [55%]; difference = 25% [95% CI: 16% to 34%]), more received respiratory support (206 [88%] vs 71 [38%]; difference = 50% [95% CI: 34% to 56%]), and more died (8 [3.4%] vs 0). Of the 235 children receiving COVID-19-directed therapies, 172 (73%) received systemic steroids and 150 (64%) received remdesivir, with rising remdesivir use over the study period (14% in March/April to 57% November/December). Conclusion: Despite the lack of pediatric data evaluating treatments for COVID-19 in critically ill children, more than half of children requiring intensive or high acuity care received COVID-19-directed therapies.
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    Detrimental effects of PCSK9 loss-of-function in the pediatric host response to sepsis are mediated through independent influence on Angiopoietin-1
    (BMC, 2023-06-26) Atreya, Mihir R.; Cvijanovich, Natalie Z.; Fitzgerald, Julie C.; Weiss, Scott L.; Bigham, Michael T.; Jain, Parag N.; Schwarz, Adam J.; Lutfi, Riad; Nowak, Jeffrey; Allen, Geoffrey L.; Thomas, Neal J.; Grunwell, Jocelyn R.; Baines, Torrey; Quasney, Michael; Haileselassie, Bereketeab; Alder, Matthew N.; Lahni, Patrick; Ripberger, Scarlett; Ekunwe, Adesuwa; Campbell, Kyle R.; Walley, Keith R.; Standage, Stephen W.; Pediatrics, School of Medicine
    Background: Sepsis is associated with significant mortality. Yet, there are no efficacious therapies beyond antibiotics. PCSK9 loss-of-function (LOF) and inhibition, through enhanced low-density lipoprotein receptor (LDLR) mediated endotoxin clearance, holds promise as a potential therapeutic approach among adults. In contrast, we have previously demonstrated higher mortality in the juvenile host. Given the potential pleiotropic effects of PCSK9 on the endothelium, beyond canonical effects on serum lipoproteins, both of which may influence sepsis outcomes, we sought to test the influence of PCSK9 LOF genotype on endothelial dysfunction. Methods: Secondary analyses of a prospective observational cohort of pediatric septic shock. Genetic variants of PCSK9 and LDLR genes, serum PCSK9, and lipoprotein concentrations were determined previously. Endothelial dysfunction markers were measured in day 1 serum. We conducted multivariable linear regression to test the influence of PCSK9 LOF genotype on endothelial markers, adjusted for age, complicated course, and low- and high-density lipoproteins (LDL and HDL). Causal mediation analyses to test impact of select endothelial markers on the association between PCSK9 LOF genotype and mortality. Juvenile Pcsk9 null and wildtype mice were subject to cecal slurry sepsis and endothelial markers were quantified. Results: A total of 474 patients were included. PCSK9 LOF was associated with several markers of endothelial dysfunction, with strengthening of associations after exclusion of those homozygous for the rs688 LDLR variant that renders it insensitive to PCSK9. Serum PCSK9 was not correlated with endothelial dysfunction. PCSK9 LOF influenced concentrations of Angiopoietin-1 (Angpt-1) upon adjusting for potential confounders including lipoprotein concentrations, with false discovery adjusted p value of 0.042 and 0.013 for models that included LDL and HDL, respectively. Causal mediation analysis demonstrated that the effect of PCSK9 LOF on mortality was mediated by Angpt-1 (p = 0.0008). Murine data corroborated these results with lower Angpt-1 and higher soluble thrombomodulin among knockout mice with sepsis relative to the wildtype. Conclusions: We present genetic and biomarker association data that suggest a potential direct role of the PCSK9-LDLR pathway on Angpt-1 in the developing host with septic shock and warrant external validation. Further, mechanistic studies on the role of PCSK9-LDLR pathway on vascular homeostasis may lead to the development of pediatric-specific sepsis therapies.
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    Differential resting-state patterns across networks are spatially associated with Comt and Trmt2a gene expression patterns in a mouse model of 22q11.2 deletion
    (Elsevier, 2021) Gass, Natalia; Peterson, Zeru; Reinwald, Jonathan; Sartorius, Alexander; Weber-Fahr, Wolfgang; Sack, Markus; Chen, Junfang; Cao, Han; Didriksen, Michael; Stensbøl, Tine Bryan; Klemme, Gabriele; Schwarz, Adam J.; Schwarz, Emanuel; Meyer-Lindenberg, Andreas; Nickl-Jockschat, Thomas; Radiology and Imaging Sciences, School of Medicine
    Copy number variations (CNV) involving multiple genes are ideal models to study polygenic neuropsychiatric disorders. Since 22q11.2 deletion is regarded as the most important single genetic risk factor for developing schizophrenia, characterizing the effects of this CNV on neural networks offers a unique avenue towards delineating polygenic interactions conferring risk for the disorder. We used a Df(h22q11)/+ mouse model of human 22q11.2 deletion to dissect gene expression patterns that would spatially overlap with differential resting-state functional connectivity (FC) patterns in this model (N = 12 Df(h22q11)/+ mice, N = 10 littermate controls). To confirm the translational relevance of our findings, we analyzed tissue samples from schizophrenia patients and healthy controls using machine learning to explore whether identified genes were co-expressed in humans. Additionally, we employed the STRING protein-protein interaction database to identify potential interactions between genes spatially associated with hypo- or hyper-FC. We found significant associations between differential resting-state connectivity and spatial gene expression patterns for both hypo- and hyper-FC. Two genes, Comt and Trmt2a, were consistently over-expressed across all networks. An analysis of human datasets pointed to a disrupted co-expression of these two genes in the brain in schizophrenia patients, but not in healthy controls. Our findings suggest that COMT and TRMT2A form a core genetic component implicated in differential resting-state connectivity patterns in the 22q11.2 deletion. A disruption of their co-expression in schizophrenia patients points out a prospective cause for the aberrance of brain networks communication in 22q11.2 deletion syndrome on a molecular level.