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There is an urgent need for simple and non-invasive identification of live neural stem/progenitor cells (NSPCs) in the developing and adult brain as well as in disease, such as in brain tumors, due to the potential clinical importance in prognosis, diagnosis, and treatment of diseases of the nervous system. Here, we report a luminescent conjugated oligothiophene (LCO), named p-HTMI, for non-invasive and non-amplified real-time detection of live human patient-derived glioblastoma (GBM) stem cell-like cells and NSPCs. While p-HTMI stained only a small fraction of other cell types investigated, the mere addition of p-HTMI to the cell culture resulted in efficient detection of NSPCs or GBM cells from rodents and humans within minutes. p-HTMI is functionalized with a methylated imidazole moiety resembling the side chain of histidine/histamine, and non-methylated analogues were not functional. Cell sorting experiments of human GBM cells demonstrated that p-HTMI labeled the same cell population as CD271, a proposed marker for stem cell-like cells and rapidly migrating cells in glioblastoma. Our results suggest that the LCO p-HTMI is a versatile tool for immediate and selective detection of neural and glioma stem and progenitor cells.

There is an intimate body-brain connection in ageing, and obesity is a key risk factor for poor cardiometabolic health and neurodegenerative conditions. Although research has demonstrated deleterious effects of obesity on brain structure and function, the majority of studies have used conventional measures such as waist-to-hip ratio, waist circumference, and body mass index. While sensitive to gross features of body composition, such global anthropometric features fail to describe regional differences in body fat distribution and composition. The sample consisted of baseline brain magnetic resonance imaging (MRI) acquired from 790 healthy participants aged 18-94 years (mean +/- standard deviation (SD) at baseline: 46.8 +/- 16.3), and follow-up brain MRI collected from 272 of those individuals (two time-points with 19.7 months interval, on average (min = 9.8, max = 35.6). Of the 790 included participants, cross-sectional body MRI data was available from a subgroup of 286 participants, with age range 19-86 (mean = 57.6, SD = 15.6). Adopting a mixed cross-sectional and longitudinal design, we investigated cross-sectional body magnetic resonance imaging measures of adipose tissue distribution in relation to longitudinal brain structure using MRI-based morphometry (T1) and diffusion tensor imaging (DTI). We estimated tissue-specific brain age at two time points and performed Bayesian multilevel modelling to investigate the associations between adipose measures at follow-up and brain age gap (BAG) - the difference between actual age and the prediction of the brains biological age - at baseline and follow-up. We also tested for interactions between BAG and both time and age on each adipose measure. The results showed credible associations between T1-based BAG and liver fat, muscle fat infiltration (MFI), and weight-to-muscle ratio (WMR), indicating older-appearing brains in people with higher measures of adipose tissue. Longitudinal evidence supported interaction effects b, Funding Agencies|Research Council of Norway [223273, 249795, 248238, 276082]; South-Eastern Norway Regional Health Authority [2014097, 2015044, 2015073, 2016083, 2018037, 2018076]; Norwegian ExtraFoundation for Health and Rehabilitation [2015/FO5146]; KG Jebsen Stiftelsen; Swiss National Science Foundation [PZ00P3_193658]; German Federal Ministry of Education and Research (BMBF) [01ZX1904A]; ERA-Net Cofund through the ERA PerMed project IMPLEMENT (Research Council of Norway) [298646]; European Research Council under the European Unions Horizon 2020 Research and Innovation program (ERC StG) [802998, 847776]

Background & Aims Obesity and associated morbidities, metabolic associated liver disease (MAFLD) included, constitute some of the largest public health threats worldwide. Body composition and related risk factors are known to be heritable and identification of their genetic determinants may aid in the development of better prevention and treatment strategies. Recently, large-scale whole-body MRI data has become available, providing more specific measures of body composition than anthropometrics such as body mass index. Here, we aimed to elucidate the genetic architecture of body composition, by conducting the first genome-wide association study (GWAS) of these MRI-derived measures. Methods We ran both univariate and multivariate GWAS on fourteen MRI-derived measurements of adipose and muscle tissue distribution, derived from scans from 34,036 White European UK Biobank participants (mean age of 64.5 years, 51.5% female). Results Through multivariate analysis, we discovered 108 loci with distributed effects across the body composition measures and 256 significant genes primarily involved in immune system functioning. Liver fat stood out, with a highly discoverable and oligogenic architecture and the strongest genetic associations. Comparison with 21 common cardiometabolic traits revealed both shared and specific genetic influences, with higher mean heritability for the MRI measures (h2=.25 vs. .16, p=1.4×10−6). We found substantial genetic correlations between the body composition measures and a range of cardiometabolic diseases, with the strongest correlation between liver fat and type 2 diabetes (rg=.48, p=1.6×10−22). Conclusions These findings show that MRI-derived body composition measures complement conventional body anthropometrics and other biomarkers of cardiometabolic health, highlighting the central role of liver fat, and improving our knowledge of the genetic architecture of body composition and related diseases., Preprint distributet via bioRxiv

Objectives As meditation is increasingly employed for the promotion of good health, there is a growing interest in using neuroimaging methods to investigate the neural mechanisms by which meditation acts. In the wake of this rising interest, criticism regarding the lack of clarity concerning theory, definitions, and taxonomy, as well as deficient or poorly reported methodology, has arisen. The aim of this study was to investigate trends in current neuroimaging research on meditation and to provide guidelines for future studies. Methods We made a literature search for articles published during 2016-2019 using the search phrases "meditation" and "functional magnetic resonance imaging or fMRI". Inclusion criteria were limited to meditation studies using resting-state fMRI or such task-based fMRI examinations that were specifically targeting meditative states in healthy participants. Text analysis was performed using Nvivo 12 Mac (QSR International). Results Twenty-eight articles were included from which we identified four different intention-based dimensions of meditation practice: The present moment, Wholesome qualities to cultivate, Unwholesome qualities to avoid, and Attitudes. Half of the studies do not make assessments of subjective experience. The results were related to networks and brain regions describing cognitive, affective, somatic, and self domains of brain function. Most studies describe meditation-related brain function in terms of "processes". Conclusions We defined five areas of potential improvement regarding research methodology: (1) Provide clear and unambiguous definitions of constructs and practices, (2) Include measures of subjective experience, (3) Perform correct assessment of processes, (4) Combine methodologies for more substantiated conclusions, (5) Avoid the risk of overinterpretation., Funding Agencies|Linkoping University

Vasoactive intestinal polypeptide (VIP) is a neuroendocrine peptide distributed throughout the human body, including the CNS, where it is particularly abundant in brain regions associated with anxiety and depression. Based on earlier studies indicating that peripheral VIP may cross through the blood-brain barrier, we hypothesized plasma VIP levels to be associated with symptoms of anxiety and depression, as well as brain volume and resting-state functional connectivity in the amygdala, hippocampus, parahippocampus, and orbitofrontal cortex. Plasma VIP concentrations and anxiety/depression symptoms were measured in 37 healthy females. Functional and structural magnetic resonance imaging were used to evaluate functional connectivity and brain volume respectively, and their associations with VIP concentrations within brain regions associated with anxiety and depression. Negative correlations were found between VIP levels and symptoms of anxiety (r=- 0.44, p=0.002) and depression (r=- 0.50, p=0.001). Functional connectivity demonstrated significant VIP-dependent positive associations between the amygdala seed region with both the right parahippocampus (t((33))=3.1, p(FDR)=0.02) and right lateral orbitofrontal cortex (OFC; t((33))=2.9, p(FDR)=0.02). Moreover, VIP concentrations were significantly, positively correlated with brain volume in the left amygdala (r=0.28, p=0.007) and left lateral OFC (r=0.29, p=0.004). The present findings highlight a potential role for VIP in the neurobiology of affective symptoms., Funding Agencies|Linkoping University Library

Magnetotactic bacteria (MTB), ubiquitous in soil and fresh and saltwater sources have been identified in the microbiome of humans and many animals. MTB endogenously produce magnetic nanocrystals enabling them to orient and navigate along geomagnetic fields. Similar magnetite deposits have been found throughout the tissues of the human brain, including brain regions associated with orientation such as the cerebellum and hippocampus, the origins of which remain unknown. Speculation over the role and source of MTB in humans, as well as any association with the brain, remain unanswered. We performed a metagenomic analysis of the gut microbiome of 34 healthy females as well as grey matter volume analysis in magnetite-rich brain regions associated with orientation and navigation with the goal of identifying specific MTB that could be associated with brain structure in orientation and navigation regions. We identified seven MTB in the human gut microbiome: Magnetococcus marinus, Magnetospira sp. QH-2, Magnetospirillum magneticum, Magnetospirillum sp. ME-1, Magnetospirillum sp. XM-1, Magnetospirillum gryphiswaldense, and Desulfovibrio magneticus. Our preliminary results show significant negative associations between multiple MTB with bilateral flocculonodular lobes of the cerebellum and hippocampus (adjusted for total intracranial volume, uncorrected P<0.05). These findings indicate that MTB in the gut are associated with grey matter volume in magnetite-rich brain regions related to orientation and navigation. These preliminary findings support MTB as a potential biogenic source for brain magnetite in humans. Further studies will be necessary to validate and elucidate the relationship between these bacteria, magnetite concentrations, and brain function., Funded by: The AFA Insurance Research Foundation, the County Council of Östergotland, a Bengt Ihre Research Fellowship and the Ruth and Richard Julin Foundation. DAB was supported by the US National Science Foundation (No. EAR-1423939)

We present an application, and its development process, for interactive visual analysis of brain imaging data and clinical measurements. The application targets neuroscientists interested in understanding the correlations between active brain regions and physiological or psychological factors. The application has been developed in a participatory design process and has subsequently been released as the free software VisualNeuro. From initial observations of the neuroscientists workflow, we concluded that while existing tools provide powerful analysis options, they lack effective interactive exploration requiring the use of many tools side by side. Consequently, our application has been designed to simplify the workflow combining statistical analysis with interactive visual exploration. The resulting environment comprises parallel coordinates for effective overview and selection, Welchs t-test to filter out brain regions with statistically significant differences and multiple visualizations for comparison between brain regions and clinical parameters. These exploration concepts enable neuroscientists to interactively explore the complex bidirectional interplay between clinical and brain measurements and easily compare different patient groups. A qualitative user study has been performed with three neuroscientists from different domains. The study shows that the developed environment supports simultaneous analysis of more parameters, provides rapid pathways to insights and is an effective tool for hypothesis formation., Funding Agencies|grants Seeing Organ Function from the Knut and Alice Wallenberg Foundation (KAW) [2013-0076]; Swedish research councilSwedish Research Council [2015-05462]; SeRC (Swedish e-Science Research Centre); ELLIIT environment for strategic research in Sweden; Center for Medical Image science and Visualization (CMIV) at Linkoping University

n/a, Funding Agencies|Region Ostergotland; Bengt-Ihre Fond

Knowledge about the neural underpinnings of the negative blood oxygen level dependent (BOLD) responses in functional magnetic resonance imaging (fMRI) is still limited. We hypothesized that pharmacological GABAergic modulation attenuates BOLD responses, and that blood concentrations of a positive allosteric modulator of GABA correlate inversely with BOLD responses in the cingulate cortex. We investigated whether or not pure task-related negative BOLD responses were co-localized with pharmacologically modulated BOLD responses. Twenty healthy adults received either 5 mg diazepam or placebo in a double blind, randomized design. During fMRI the subjects performed a working memory task. Results showed that BOLD responses in the cingulate cortex were inversely correlated with diazepam blood concentrations; that is, the higher the blood diazepam concentration, the lower the BOLD response. This inverse correlation was most pronounced in the pregenual anterior cingulate cortex and the anterior mid-cingulate cortex. For subjects with diazepam plasma concentration > 0.1 mg/L we observed negative BOLD responses with respect to fixation baseline. There was minor overlap between cingulate regions with task-related negative BOLD responses and regions where the BOLD responses were inversely correlated with diazepam concentration. We interpret that the inverse correlation between the BOLD response and diazepam was caused by GABA-related neural inhibition. Thus, this study supports the hypothesis that GABA attenuates BOLD responses in fMRI. The minimal overlap between task-related negative BOLD responses and responses attenuated by diazepam suggests that these responses might be caused by different mechanisms., Funding agencies: Linkoping University; County Council of Ostergotland

Ligands for identifying protein aggregates are of great interest as such deposits are the pathological hallmark of a wide range of severe diseases including Alzheimers and Parkinsons disease. Here we report the synthesis of an azide functionalized fluorescent pentameric oligothiophene that can be utilized as a ligand for multimodal detection of disease-associated protein aggregates. The azide functionalization allows for attachment of the ligand to a surface by conventional click chemistry without disturbing selective interaction with protein aggregates and the oligothiophene-aggregate interaction can be detected by fluorescence or surface plasmon resonance. In addition, a methodology where the oligothiophene ligand is employed as a capturing molecule selective for aggregated proteins in combination with an antibody detecting a distinct peptide/protein is also presented. We foresee that this methodology will offer the possibility to create a variety of multiplex sensing systems for sensitive and selective detection of protein aggregates, the pathological hallmarks of several neurodegenerative diseases., Funding Agencies|Swedish Foundation for Strategic Research; Ehrling Persson Foundation; ERC Starting Independent Researcher grant (Project: MUMID)

The default mode network (DMN) is a group of anatomically separate regions in the brain found to have synchronized patterns of activation in functional magnetic resonance imaging (fMRI). Mentation associated with the DMN includes processes such as mind wandering, autobiographical memory, self-reflective thought, envisioning the future, and considering the perspective of others. Abnormalities in the DMN have been linked to symptom severity in a variety of mental disorders indicating that the DMN could be used as a biomarker for diagnosis. These correlations have also led to the use of DMN modulation as a biomarker for assessing pharmacological treatments. Concurrent research investigating the neural correlates of meditation, have associated DMN modulation with practice. Furthermore, meditative practice is increasingly understood to have a beneficial role in the treatment of mental disorders. Therefore we propose the use of DMN measures as a biomarker for monitoring the therapeutic effects of meditation practices in mental disorders. Recent findings support this perspective, and indicate the utility of DMN monitoring in understanding and developing meditative treatments for these debilitating conditions.

A wide range of neurodegenerative diseases are characterized by the deposition of multiple protein aggregates. Ligands for molecular characterization and discrimination of these pathological hallmarks are thus important for understanding their potential role in pathogenesis as well as for clinical diagnosis of the disease. In this regard, luminescent conjugated oligothiophenes (LCOs) have proven useful for spectral discrimination of amyloid-beta (Aβ) and tau neurofibrillary tangles (NFTs), two of the pathological hallmarks associated with Alzheimer’s disease. Herein, the solvatochromism of a library of anionic pentameric thiophene-based ligands, as well as their ability to spectrally discriminate Aβ and tau aggregates, were investigated. Overall, the results from this study identified distinct solvatochromic and viscosity-dependent behavior of thiophene-based ligands that can be applied as indices to direct the chemical design of improved LCOs for spectral separation of Aβ and tau aggregates in brain tissue sections. The results also suggest that the observed spectral transitions of the ligands are due to their ability to conform by induced fit to specific microenvironments within the binding interface of each particular protein aggregate. We foresee that these findings might aid in the chemical design of thiophene-based ligands that are increasingly selective for distinct disease-associated protein aggregates.

Luminescent conjugated oligothiophenes (LCOs) represent a useful and interesting class of materials well known for their abilities as transducers for colorimetric and fluorometric reporting. Specifically, they have the ability to produce a conformation-dependent spectral signature reflective of changes in their local environment. This physical property makes conjugated polymers an indispensible tool in the toolbox of fluorescent reporters used for distinguishing protein aggregates. Because fluorescence measurements provide a number of parameters for observing changes within a system (e.g., changes in intensity, wavelength, energy transfer, and emission lifetime), the coupling of such measurements with the unique fluorescence reporting capabilities of LCOs has been successful in a number of biological systems. The Nilsson group has demonstrated the use of both polydisperse and monodisperse conjugated polythiophenes for the purpose of amyloid protein aggregate detection both in vitro and ex vivo. My doctoral studies have included synthesis and the photophysical evaluation of pentameric substituted oligothiophenes for utilization as molecular probes for investigating the structure and conformation of amyloid protein aggregates. Through the synthesis of a library of pentameric probes with variations in side-chain substituents, we have studied the effects of pH, solvent, and viscosity on probe behavior and spectral shifts to elucidate the role of chemical structure on probe performance. Through a clearer understanding of the nature of LCOs and their individual chromic responses, we hope to provide researchers and clinicians additional tools for investigating and “bringing to light” the multifaceted nature of amyloids.

Understanding the photo-physical processes in fluorescent probes are essential as such dyes are widely utilized in molecular biology. Here we report the pH-dependent optical transitions of a library of anionic pentameric luminescent conjugated oligothiophenes (LCOs) that have been used for fluorescent identification of protein aggregates, the pathological hallmark of many devastating diseases. Absorption-, excitation- and emission spectra were recorded for all LCOs in different buffers with a pH range from 3.5 to 7. p-FTAA, a LCO having a central core consisting of a trimeric thiophene building block with head-to-head acetic acid functionalization as well as terminal carboxyl groups extending the pentameric thiophene backbone, displayed pH/dependent optical characteristics correlating to a non-planar to planar transition of the conjugated backbone as well as aggregation between adjacent thiophene chain upon protonation of the acetic acid side chains. In contrast, chemically related analogues to p-FTAA lacking the terminal carboxyl groups extending the pentameric thiophene backbone or the conformational ability to undergo a non/planar to planar transition of the conjugated backbone, displayed different optical characteristics compared to p-FTAA. Overall these studies highlighted that minor chemical alteration of LCOs can result in major difference in the optical characteristics obtained from the dyes and the results might aid in designing novel LCOs that have superior optical performance as amyloid ligands.

Molecular and electronic structures and optical absorption properties of oligothiophenes used for spectral assignment of amyloid deposits have been investigated for a family of probes known as luminescent conjugated oligothiophenes (LCOs). Theoretical absorption spectra have been determined using conformational averaging, combining classical molecular dynamics (MD) simulations with quantum mechanical/molecular mechanics (QM/MM) time-dependent density functional theory (TD-DFT) spectrum calculations. Theoretical absorption spectra are in excellent agreement with experiments, showing average errors below 5 nm for absorption maxima. To couple observed properties to molecular structures, a measure of planarity is defined, revealing a strong correlation between the transition wavelength of the first and dominating electronically excited state and dihedral rotations. It is shown that from this correlation, predictions can be made of the absorption properties of probes based only on information from MD trajectories. We show experimentally that red shifts observed in the excitation maxima of LCOs when bound to amyloid protein aggregates are also evident in absorption spectra. We predict that these red shifts are due to conformational restriction of the LCO in a protein binding pocket, causing a planarization of the conjugated backbone. On the basis of our studies of planarity, it is shown that such shifts are both possible and realistic., At the time for thesis presentation publication was in status: ManuscriptFunding agencies: We acknowledge financial support from the Swedish Research Council (Grant No. 621-2010-5014) as well as a grant for computing time at the National Supercomputer Centre (NSC), Sweden. M.L. thanks the Swedish e-Science Research Center (SeRC) for financial support. Our work is supported by the Swedish Foundation for Strategic Research (K.P.R.N., R.A.S.). K.P.R.N. is financed by an ERC Starting Independent Researcher Grant (Project: MUMID) from the European Research Council. R.A.S. is enrolled in the doctoral program Forum Scientum. M.L. is grateful to Linkoping University for a guest professorship. Parts of this work were supported by the LUPAS project supported by the EU FP7 program.

The disease-associated prion protein (PrP) forms aggregates which vary in structural conformation yet share identical primary sequence. These variations in PrP conformation are believed to manifest in prion strains exhibiting distinctly different periods of disease incubation as well as regionally specific aggregate deposition within the brain. The anionic luminescent conjugated polythiophene (LCP), polythiophene acetic acid (PTAA) has previously been used to distinguish PrP deposits associated with distinct mouse adapted strains via distinct fluorescence emission profiles from the dye. Here we employed PTAA and 3 structurally related chemically defined luminescent conjugated oligothiophenes (LCOs) to stain brain tissue sections from mice inoculated with 2 distinct prion strains. Our results showed that in addition to emission spectra, excitation, and fluorescence lifetime imaging microscopy (FLIM) can fruitfully be assessed for optical distinction of PrP deposits associated with distinct prion strains. Our findings support the theory that alterations in LCP/LCO fluorescence are due to distinct conformational restriction of the thiophene backbone upon interaction with PrP aggregates associated with distinct prion strains. We foresee that LCP and LCO staining in combination with multimodal fluorescence microscopy might aid in detecting structural differences among discrete protein aggregates and in linking protein conformational features with disease phenotypes for a variety of neurodegenerative proteinopathies.

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Molecular probes for selective identification of protein aggregates are important to advance our understanding of the molecular pathogenesis underlying protein aggregation diseases. Here we report the chemical design of a library of anionic luminescent conjugated oligothiophenes (LCOs), which can be utilized as ligands for detection of protein aggregates. Certain molecular requirements were shown to be necessary for detecting (i) early non-thioflavinophilic protein assemblies of A beta 1-42 and insulin preceding the formation of amyloid fibrils and (ii) for obtaining distinct spectral signatures of the two main pathological hallmarks observed in human Alzheimers diease brain tissue (A beta plaques and neurofibrillary tangles). Our findings suggest that a superior anionic LCO-based ligand should have a backbone consisting of five to seven thiophene units and carboxyl groups extending the conjugated thiophene backbone. Such LCOs will be highly useful for studying the underlying molecular events of protein aggregation diseases and could also be utilized for the development of novel diagnostic tools for these diseases.

BACKGROUND andamp; AIMS: Mallory-Denk bodies (MDBs) are cytoplasmic protein aggregates in hepatocytes in steato-hepatitis and other liver diseases. We investigated the molecular structure of keratin 8 (K8) and 18 (K18), sequestosome 1/p62, and ubiquitin, which are the major constituents of MDBs, to investigate their formation and role in disease pathogenesis. METHODS: Luminescent conjugated oligothiophenes (LCOs), h-HTAA, and p-FTAA are fluorescent amyloid ligands that specifically bind proteins with cross beta-sheet conformation. We used LCOs to investigate conformational changes in MDBs in situ in human and murine livers as well as in transfection studies. RESULTS: LCO analysis showed cross beta-sheet conformation in human MDBs from patients with alcoholic and nonalcoholic steatohepatitis or hepatocellular carcinoma, but not in intracellular hyaline bodies, alpha(1)-antitrypsin deficiency, or ground-glass inclusions. LCOs bound to MDBs induced by 3,5diethoxycarbonyl-1,4-dihydrocollidine feeding of mice at all developmental stages. CHO-K1 cells transfected with various combinations of SQSTM1/p62, ubi, and Krt8/Krt18 showed that K8 was more likely to have cross beta-sheet conformation than K18, whereas p62 never had cross beta-sheet conformation. The different conformational properties of K8 and K18 were also shown by circular dichroism analysis. CONCLUSIONS: K8 can undergo conformational changes from predominantly alpha-helical to cross beta-sheet, which would allow it to form MDBs. These findings might account for the observation that krt8(-/-) mice do not form MDBs, whereas its excess facilitates MDB formation. LCOs might be used in diagnosis of liver disorders; they can be applied to formalin-fixed, paraffin-embedded tissues to characterize protein aggregates in liver cells., Funding Agencies|Austrian Genome Program (GEN-AU)||Medical University of Graz||Swedish Foundation for Strategic Research||Knut and Alice Wallenberg Foundation