Serotonin as a biomarker of toxin-induced Parkinsonism

BACKGROUND

Loss of dopaminergic neurons underlies the motor symptoms of Parkinson's disease (PD). However stereotypical PD symptoms only manifest after approximately 80% of dopamine neurons have died making dopamine-related motor phenotypes unreliable markers of the earlier stages of the disease. There are other non-motor symptoms, such as depression, that may present decades before motor symptoms.

METHODS

Because serotonin is implicated in depression, here we use niche, fast electrochemistry paired with mathematical modelling and machine learning to, for the first time, robustly evaluate serotonin neurochemistry in vivo in real time in a toxicological model of Parkinsonism, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

RESULTS

Mice treated with acute MPTP had lower concentrations of in vivo, evoked and ambient serotonin in the hippocampus, consistent with the clinical comorbidity of depression with PD. These mice did not chemically respond to SSRI, as strongly as control animals did, following the clinical literature showing that antidepressant success during PD is highly variable. Following L-DOPA administration, using a novel machine learning analysis tool, we observed a dynamic shift from evoked serotonin release in the hippocampus to dopamine release. We hypothesize that this finding shows, in real time, that serotonergic neurons uptake L-DOPA and produce dopamine at the expense of serotonin, supporting the significant clinical correlation between L-DOPA and depression. Finally, we found that this post L-DOPA dopamine release was less regulated, staying in the synapse for longer. This finding is perhaps due to lack of autoreceptor control and may provide a ground from which to study L-DOPA induced dyskinesia.

CONCLUSIONS

These results validate key prior hypotheses about the roles of serotonin during PD and open an avenue to study to potentially improve therapeutics for levodopa-induced dyskinesia and depression.

APE1 redox function is required for activation of Yes-associated protein 1 under reflux conditions in Barrett's-associated esophageal adenocarcinomas

BACKGROUND

Esophageal adenocarcinoma (EAC) is characterized by poor prognosis and low survival rate. Chronic gastroesophageal reflux disease (GERD) is the main risk factor for the development of Barrett's esophagus (BE), a preneoplastic metaplastic condition, and its progression to EAC. Yes-associated protein 1 (YAP1) activation mediates stem-like properties under cellular stress. The role of acidic bile salts (ABS) in promoting YAP1 activation under reflux conditions remains unexplored.

METHODS

A combination of EAC cell lines, transgenic mice, and patient-derived xenografts were utilized in this study. mRNA expression and protein levels of APE1 and YAP1 were evaluated by qRT-PCR, western blot, and immunohistochemistry. YAP1 activation was confirmed by immunofluorescence staining and luciferase transcriptional activity reporter assay. The functional role and mechanism of regulation of YAP1 by APE1 was determined by sphere formation assay, siRNA mediated knockdown, redox-specific inhibition, and co-immunoprecipitation assays.

RESULTS

We showed that YAP1 signaling is activated in BE and EAC cells following exposure to ABS, the mimicry of reflux conditions in patients with GERD. This induction was consistent with APE1 upregulation in response to ABS. YAP1 activation was confirmed by its nuclear accumulation with corresponding up-regulation of YAP1 target genes. APE1 silencing inhibited YAP1 protein induction and reduced its nuclear expression and transcriptional activity, following ABS treatment. Further investigation revealed that APE1-redox-specific inhibition (E3330) or APE1 redox-deficient mutant (C65A) abrogated ABS-mediated YAP1 activation, indicating an APE1 redox-dependent mechanism. APE1 silencing or E3330 treatment reduced YAP1 protein levels and diminished the number and size of EAC spheroids. Mechanistically, we demonstrated that APE1 regulated YAP1 stability through interaction with β-TrCP ubiquitinase, whereas APE1-redox-specific inhibition induced YAP1 poly-ubiquitination promoting its degradation.

CONCLUSION

Our findings established a novel function of APE1 in EAC progression elucidating druggable molecular vulnerabilities via targeting APE1 or YAP1 for the treatment of EAC.

The resting behavior of malaria vectors in different ecological zones of Ghana and its implications for vector control

BACKGROUND

In sub-Saharan Africa there is widespread use of long-lasting insecticidal nets and indoor residual spraying to help control the densities of malaria vectors and decrease the incidence of malaria. This study was carried out to investigate the resting behavior, host preference and infection with Plasmodium falciparum of malaria vectors in Ghana in the context of the increasing insecticide resistance of malaria vectors in sub-Saharan Africa.

METHODS

Indoor and outdoor resting anopheline mosquitoes were sampled during the dry and rainy seasons in five sites in three ecological zones [Sahel savannah (Kpalsogo, Pagaza, Libga); coastal savannah (Anyakpor); and forest (Konongo)]. Polymerase chain reaction-based molecular diagnostics were used to determine speciation, genotypes for knockdown resistance mutations (L1014S and L1014F) and the G119S ace1 mutation, specific host blood meal origins and sporozoite infection in the field-collected mosquitoes.

RESULTS

Anopheles gambiae sensu lato (s.l.) predominated (89.95%, n = 1718), followed by Anopheles rufipes (8.48%, n = 162) and Anopheles funestus s.l. (1.57%, n = 30). Sibling species of the Anopheles gambiae s.l. revealed Anopheles coluzzii accounted for 63% (95% confidence interval = 57.10-68.91) and 27% (95% confidence interval = 21.66-32.55) was Anopheles gambiae s. s.. The mean resting density of An. gambiae s.l. was higher outdoors (79.63%; 1368/1718) than indoors (20.37%; 350/1718) (Wilcoxon rank sum test, Z = - 4.815, P < 0.0001). The kdr west L1014F and the ace1 mutation frequencies were higher in indoor resting An. coluzzii and An. gambiae in the Sahel savannah sites than in the forest and coastal savannah sites. Overall, the blood meal analyses revealed that a larger proportion of the malaria vectors preferred feeding on humans (70.2%) than on animals (29.8%) in all of the sites. Sporozoites were only detected in indoor resting An. coluzzii from the Sahel savannah (5.0%) and forest (2.5%) zones.

CONCLUSIONS

This study reports high outdoor resting densities of An. gambiae and An. coluzzii with high kdr west mutation frequencies, and the presence of malaria vectors indoors despite the use of long-lasting insecticidal nets and indoor residual spraying. Continuous monitoring of changes in the resting behavior of mosquitoes and the implementation of complementary malaria control interventions that target outdoor resting Anopheles mosquitoes are necessary in Ghana.

Liquid-liquid phase separation of Tau by self and complex coacervation

The liquid-liquid phase separation (LLPS) of Tau has been postulated to play a role in modulating the aggregation property of Tau, a process known to be critically associated with the pathology of a broad range of neurodegenerative diseases including Alzheimer's Disease. Tau can undergo LLPS by homotypic interaction through self-coacervation (SC) or by heterotypic association through complex-coacervation (CC) between Tau and binding partners such as RNA. What is unclear is in what way the formation mechanisms for self and complex coacervation of Tau are similar or different, and the addition of a binding partner to Tau alters the properties of LLPS and Tau. A combination of in vitro experimental and computational study reveals that the primary driving force for both Tau CC and SC is electrostatic interactions between Tau-RNA or Tau-Tau macromolecules. The liquid condensates formed by the complex coacervation of Tau and RNA have distinctly higher micro-viscosity and greater thermal stability than that formed by the SC of Tau. Our study shows that subtle changes in solution conditions, including molecular crowding and the presence of binding partners, can lead to the formation of different types of Tau condensates with distinct micro-viscosity that can coexist as persistent and immiscible entities in solution. We speculate that the formation, rheological properties and stability of Tau droplets can be readily tuned by cellular factors, and that liquid condensation of Tau can alter the conformational equilibrium of Tau.

Impact of sodium glucose linked cotransporter-2 inhibition on renal microvascular oxygen tension in a rodent model of diabetes mellitus

BACKGROUND

The mechanisms whereby inhibitors of sodium-glucose linked cotransporter-2 (SGLT2) exert their nephroprotective effects in patients with diabetes are incompletely understood but have been hypothesized to include improved tissue oxygen tension within the renal cortex. The impact of SGLT2 inhibition is likely complex and region specific within the kidney. We hypothesize that SGLT2 inhibitors have differential effects on renal tissue oxygen delivery and consumption in specific regions of the diabetic kidney, including the superficial cortex, containing SGLT2-rich components of proximal tubules, versus the deeper cortex and outer medulla, containing predominantly SGLT1 receptors.

METHODS

We measured glomerular filtration rate (GFR), microvascular kidney oxygen tension (Pk O2 ), erythropoietin (EPO) mRNA, and reticulocyte count in diabetic rats (streptozotocin) treated with the SGLT2 inhibitor, dapagliflozin. Utilizing phosphorescence quenching by oxygen and an intravascular oxygen sensitive probe (Oxyphor PdG4); we explored the effects of SGLT2 inhibition on Pk O2 in a region-specific manner, in vivo, in diabetic and non-diabetic rats. Superficial renal cortical or deeper cortical and outer medullary Pk O2 were measured utilizing excitations with blue and red light wavelengths, respectively.

RESULTS

In diabetic rats treated with dapagliflozin, measurement within the superficial cortex (blue light) demonstrated no change in Pk O2 . By contrast, measurements in the deeper cortex and outer medulla (red light) demonstrated a significant reduction in Pk O2 in dapagliflozin treated diabetic rats (p = 0.014). Consistent with these findings, GFR was decreased, hypoxia-responsive EPO mRNA levels were elevated and reticulocyte counts were increased with SGLT2 inhibition in diabetic rats (p < 0.05 for all).

CONCLUSIONS

These findings indicate that microvascular kidney oxygen tension is maintained in the superficial cortex but reduced in deeper cortical and outer medullary tissue, possibly due to the regional impact of SGLT-2 inhibition on tissue metabolism. This reduction in deeper Pk O2 had biological impact as demonstrated by increased renal EPO mRNA levels and circulating reticulocyte count.

Review article: diagnosis, management and patient perspectives of the spectrum of constipation disorders

BACKGROUND

Chronic constipation is a common, heterogeneous disorder with multiple symptoms and pathophysiological mechanisms. Patients are often referred to a gastroenterology provider after laxatives fail. However, there is limited knowledge of the spectrum and management of constipation disorders.

AIM

To discuss the latest understanding of the spectrum of constipation disorders, tools for identifying a pathophysiologic-based diagnosis in the specialist setting, treatment options and the patient's perspective of constipation.

METHODS

Literature searches were conducted using PubMed for constipation diagnostic criteria, diagnostic tools and approved treatments. The authors provided insight from their own practices.

RESULTS

Clinical assessment, stool diaries and Rome IV diagnostic criteria can facilitate diagnosis, evaluate severity and distinguish between IBS with constipation, chronic idiopathic constipation and dyssynergic defecation. Novel smartphone applications can help track constipation symptoms. Rectal examinations, anorectal manometry and balloon expulsion, assessments of neuromuscular function with colonic transit time and colonic manometry can provide mechanistic understanding of underlying pathophysiology. Treatments include lifestyle and diet changes, biofeedback therapy and pharmacological agents. Several classes of laxatives, as well as prokinetic and prosecretory agents, are available; here we describe their mechanisms of action, efficacy and side effects.

CONCLUSIONS

Constipation includes multiple overlapping subtypes identifiable using detailed history, current diagnostic tools and smartphone applications. Recognition of individual subtype(s) could pave the way for optimal, evidence-based treatments by a gastroenterology provider.

Risk of dietary and breastmilk exposure to mycotoxins among lactating women and infants 2-4 months in northern India

Mycotoxins are carcinogenic secondary metabolites of fungi that have been linked to infant growth faltering. In this study, we quantified co-occurring mycotoxins in breast milk and food samples from Haryana, India, and characterized determinants of exposure. Deterministic risk assessment was conducted for mothers and infants. We examined levels of eight mycotoxins (Aflatoxin B1 , B2 , G1 , G2 , M1 , M2 ; Ochratoxin A, B) in 100 breast milk samples (infants 2-4 months) using ultra-high-performance liquid chromatography tandem mass spectrometry. Aflatoxin B1 (AFB1 ), fumonisin B1 (FB1 ) and deoxynivalenol (DON) were detected in several food items (n = 298) using enzyme-linked immunosorbent assays. We report novel data on the presence of mycotoxins in breast milk samples from India. Whereas breast milk concentrations (AFM1 median: 13.7; range: 3.9-1200 ng/L) remain low, AFM1 was detected above regulatory limits in 27% of animal milk samples. Additionally, 41% of infants were above provisional maximum tolerable daily intake (PMTDI) limits for AFM1 due to consumption of breast milk (mean: 3.04, range: 0.26-80.7 ng kg-1 bw day-1 ). Maternal consumption of breads (p < 0.05) was associated with breast milk AFM1 exposure. AFB1 (μg/kg) was detected in dried red chilies (15.7; 0-302.3), flour (3.13; 0-214.9), groundnuts (0; 0-249.1), maize (56.0; 0-836.7), pearl millet (1.85; 0-160.2), rice (0; 0-195.6), wheat (1.9; 0-196.0) and sorghum (0; 0-63.5). FB1 (mg/kg) was detected in maize (0; 0-61.4), pearl millet (0; 0-35.4) and sorghum (0.95; 0-33.2). DON was not detected in food samples. Mothers in our study exceeded PMTDI recommendations for AFB1 due to consumption of rice and flour (mean: 75.81; range: 35.2-318.2 ng kg-1 bw day-1 ). Our findings show the presence of Aflatoxin B1 and M1 at various levels of the food chain and in breast milk, with estimated intakes exceeding PMTDI recommendations. Aflatoxins are known carcinogens and have also been linked to stunting in children. Their presence across the food system and in breast milk is concerning, thus warranting further research to replicate and expand on our findings and to understand implications for maternal and child health.

Fine-tuning p53 activity by modulating the interaction between eukaryotic translation initiation factor eIF4E and RNA-binding protein RBM38

p53 is critical for tumor suppression but also elicits detrimental effects when aberrantly overexpressed. Thus, multiple regulators, including RNA-binding protein RBM38, are found to tightly control p53 expression. Interestingly, RBM38 is unique in that it can either suppress or enhance p53 mRNA translation via altered interaction with eIF4E potentially mediated by serine-195 (S195) in RBM38. Thus, multiple RBM38/eIF4E knock-in (KI) cell lines were generated to investigate the significance of eIF4E-RBM38 interaction in controlling p53 activity. We showed that KI of RBM38-S195D or -Y192C enhances, whereas KI of RBM38-S195K/R/L weakens, the binding of eIF4E to p53 mRNA and subsequently p53 expression. We also showed that KI of eIF4E-D202K weakens the interaction of eIF4E with RBM38 and thereby enhances p53 expression, suggesting that D202 in eIF4E interacts with S195 in RBM38. Moreover, we generated an Rbm38 S193D KI mouse model in which human-equivalent serine-193 is substituted with aspartic acid. We showed that S193D KI enhances p53-dependent cellular senescence and that S193D KI mice have a shortened life span and are prone to spontaneous tumors, chronic inflammation, and liver steatosis. Together, we provide in vivo evidence that the RBM38-eIF4E loop can be explored to fine-tune p53 expression for therapeutic development.

Post-eclosion temperature effects on insect cuticular hydrocarbon profiles

The insect cuticle is the interface between internal homeostasis and the often harsh external environment. Cuticular hydrocarbons (CHCs) are key constituents of this hard cuticle and are associated with a variety of functions including stress response and communication. CHC production and deposition on the insect cuticle vary among natural populations and are affected by developmental temperature; however, little is known about CHC plasticity in response to the environment experienced following eclosion, during which time the insect cuticle undergoes several crucial changes. We targeted this crucial to important phase and studied post-eclosion temperature effects on CHC profiles in two natural populations of Drosophila melanogaster. A forty-eight hour post-eclosion exposure to three different temperatures (18, 25, and 30°C) significantly affected CHCs in both ancestral African and more recently derived North American populations of D. melanogaster. A clear shift from shorter to longer CHCs chain length was observed with increasing temperature, and the effects of post-eclosion temperature varied across populations and between sexes. The quantitative differences in CHCs were associated with variation in desiccation tolerance among populations. Surprisingly, we did not detect any significant differences in water loss rate between African and North American populations. Overall, our results demonstrate strong genetic and plasticity effects in CHC profiles in response to environmental temperatures experienced at the adult stage as well as associations with desiccation tolerance, which is crucial in understanding holometabolan responses to stress.

TEAD-YAP Interaction Inhibitors and MDM2 Binders from DNA-Encoded Indole-Focused Ugi Peptidomimetics

DNA-encoded combinatorial synthesis provides efficient and dense coverage of chemical space around privileged molecular structures. The indole side chain of tryptophan plays a prominent role in key, or "hot spot", regions of protein-protein interactions. A DNA-encoded combinatorial peptoid library was designed based on the Ugi four-component reaction by employing tryptophan-mimetic indole side chains to probe the surface of target proteins. Several peptoids were synthesized on a chemically stable hexathymidine adapter oligonucleotide "hexT", encoded by DNA sequences, and substituted by azide-alkyne cycloaddition to yield a library of 8112 molecules. Selection experiments for the tumor-relevant proteins MDM2 and TEAD4 yielded MDM2 binders and a novel class of TEAD-YAP interaction inhibitors that perturbed the expression of a gene under the control of these Hippo pathway effectors.

Prodromal Markers of Upper Limb Deficits in FMR1 Premutation Carriers and Quantitative Outcome Measures for Future Clinical Trials in Fragile X-associated Tremor/Ataxia Syndrome

BACKGROUND

Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a rare, late-onset neurodegenerative disorder characterized by tremor and cerebellar gait ataxia, affecting premutation carriers (PMC) of CGG expansions (range, 55-200) in the fragile X mental retardation 1 (FMR1) gene. Discovery of early predictors for FXTAS and quantitative characterization of motor deficits are critical for identifying disease onset, monitoring disease progression, and determining efficacy of interventions.

METHODS

A total of 39 PMC with FXTAS, 20 PMC without FXTAS, and 27 healthy controls performed a series of upper extremity (UE) motor tasks assessing tremor, bradykinesia, and rapid alternating movements that were quantified using an inertial-based sensor system (Kinesia One; Great Lakes NeuroTechnologies, Cleveland, OH, USA). Sub-scores from the clinician-rated FXTAS Rating Scale were correlated with the severity scores generated by the sensor system to determine its validity in FXTAS.

RESULTS

PMC with FXTAS had significantly worse postural and kinetic tremor compared with PMC without FXTAS (P = 0.02, 0.03) and controls (P = 0.001, 0.0001), respectively, and slower finger tap (P = 0.001), hand movement (P = 0.0001), and rapid alternating movement speed (P = 0.003) and amplitude (P = 0.04) than controls. PMC without FXTAS had significantly worse right finger tap (P = 0.004), hand movement (P = 0.01), and rapid alternating movement speed (P = 0.003) and amplitude (P = 0.02) than controls. FXTAS Rating Scale subscores significantly correlated with all tremorography scores except for finger taps and left rapid alternating movement.

CONCLUSIONS

These findings support the use of inertial sensor quantification systems as promising measures for preclinical FXTAS symptom detection in PMC, characterization of the natural history of FXTAS, assessment of medication responses, and outcome assessment in clinical trials.

Gut microbiota from androgen-altered donors alter pulmonary responses to ozone in female mice

In mice, both androgens and the gut microbiota modify pulmonary responses to ozone. We hypothesized that androgens affect gut microbiota and thereby impact pulmonary responses to ozone. To address this hypothesis, we transferred cecal microbiota from male castrated or sham castrated C57BL/6J mice into female germ-free recipient C57BL/6J mice. Four weeks later mice were exposed to ozone (2 ppm) or room air for 3 hr. The gut microbiomes of castrated versus sham castrated donors differed, as did those of recipients of microbiota from castrated versus sham castrated donors. In recipients, ozone-induced airway hyperresponsiveness was not affected by donor castration status. However, compared to mice receiving microbiota from sham castrated donors, mice receiving microbiota from castrated donors had elevated numbers of bronchoalveolar lavage (BAL) neutrophils despite evidence of reduced lung injury as measured by BAL protein. Serum concentrations of IL-17A and G-CSF were significantly greater in recipients of castrated versus sham castrated microbiota. Furthermore, BAL neutrophils correlated with both serum IL-17A and serum G-CSF. Our data indicate that androgen-mediated effects on the gut microbiota modulate pulmonary inflammatory responses to ozone and suggest a role for circulating IL-17A and G-CSF in these events.

Prospective associations, longitudinal patterns of childhood socioeconomic status, and white matter organization in adulthood

The association between childhood socioeconomic status (SES) and brain development is an emerging area of research. The primary focus to date has been on SES and variations in gray matter structure with much less known about the relation between childhood SES and white matter structure. Using a longitudinal study of SES, with measures of income-to-needs ratio (INR) at age 9, 13, 17, and 24, we examined the prospective relationship between childhood SES (age 9 INR) and white matter organization in adulthood using diffusion tensor imaging. We also examined how changes in INR from childhood through young adulthood are associated with white matter organization in adult using a latent growth mixture model. Using tract-based spatial statistics (TBSS) we found that there is a significant prospective positive association between childhood INR and white matter organization in the bilateral uncinate fasciculus, bilateral cingulum bundle, bilateral superior longitudinal fasciculus, and corpus callosum (p < .05, FWE corrected). The probability that an individual was in the high-increasing INR profile across development compared with the low-increasing INR profile was positively associated with white matter organization in the bilateral uncinate fasciculus, left cingulum, and bilateral superior longitudinal fasciculus. The results of the current study have potential implications for interventions given that early childhood poverty may have long-lasting associations with white matter structure. Furthermore, trajectories of socioeconomic status during childhood are important-with individuals that belong to the latent profile that had high increases in INR having greater regional white matter organization in adulthood.

Lineage-specific differentiation of osteogenic progenitors from pluripotent stem cells reveals the FGF1-RUNX2 association in neural crest-derived osteoprogenitors

Human pluripotent stem cells (hPSCs) can provide a platform to model bone organogenesis and disease. To reflect the developmental process of the human skeleton, hPSC differentiation methods should include osteogenic progenitors (OPs) arising from three distinct embryonic lineages: the paraxial mesoderm, lateral plate mesoderm, and neural crest. Although OP differentiation protocols have been developed, the lineage from which they are derived, as well as characterization of their genetic and molecular differences, has not been well reported. Therefore, to generate lineage-specific OPs from human embryonic stem cells and human induced pluripotent stem cells, we employed stepwise differentiation of paraxial mesoderm-like cells, lateral plate mesoderm-like cells, and neural crest-like cells toward their respective OP subpopulation. Successful differentiation, confirmed through gene expression and in vivo assays, permitted the identification of transcriptomic signatures of all three cell populations. We also report, for the first time, high FGF1 levels in neural crest-derived OPs-a notable finding given the critical role of fibroblast growth factors (FGFs) in osteogenesis and mineral homeostasis. Our results indicate that FGF1 influences RUNX2 levels, with concomitant changes in ERK1/2 signaling. Overall, our study further validates hPSCs' power to model bone development and disease and reveals new, potentially important pathways influencing these processes.

Cells of origin of lung cancers: lessons from mouse studies

As one of the most common forms of cancer, lung cancers present as a collection of different histological subtypes. These subtypes are characterized by distinct sets of driver mutations and phenotypic appearance, and they often show varying degrees of heterogenicity, aggressiveness, and response/resistance to therapy. Intriguingly, lung cancers are also capable of showing features of multiple subtypes or converting from one subtype to another. The intertumoral and intratumoral heterogeneity of lung cancers as well as incidences of subtype transdifferentiation raise the question of to what extent the tumor characteristics are dictated by the cell of origin rather than the acquired driver lesions. We provide here an overview of the studies in experimental mouse models that try to address this question. These studies convincingly show that both the cell of origin and the genetic driver lesions play a critical role in shaping the phenotypes of lung tumors. However, they also illustrate that there is far from a direct one-to-one relationship between the cell of origin and the cancer subtype, as most epithelial cells can be reprogrammed toward diverse lung cancer fates when exposed to the appropriate set of driver mutations.

Spectral graph theory of brain oscillations

The relationship between the brain's structural wiring and the functional patterns of neural activity is of fundamental interest in computational neuroscience. We examine a hierarchical, linear graph spectral model of brain activity at mesoscopic and macroscopic scales. The model formulation yields an elegant closed-form solution for the structure-function problem, specified by the graph spectrum of the structural connectome's Laplacian, with simple, universal rules of dynamics specified by a minimal set of global parameters. The resulting parsimonious and analytical solution stands in contrast to complex numerical simulations of high dimensional coupled nonlinear neural field models. This spectral graph model accurately predicts spatial and spectral features of neural oscillatory activity across the brain and was successful in simultaneously reproducing empirically observed spatial and spectral patterns of alpha-band (8-12 Hz) and beta-band (15-30 Hz) activity estimated from source localized magnetoencephalography (MEG). This spectral graph model demonstrates that certain brain oscillations are emergent properties of the graph structure of the structural connectome and provides important insights towards understanding the fundamental relationship between network topology and macroscopic whole-brain dynamics. .

Agent-based modelling reveals strategies to reduce the fitness and metastatic potential of circulating tumour cell clusters

Metastasis-the ability of cancer cells to disperse throughout the body and establish new tumours at distant locations-is responsible for most cancer-related deaths. Although both single and clusters of circulating tumour cells (CTCs) have been isolated from cancer patients, CTC clusters are generally associated with higher metastatic potential and worse prognosis. From an evolutionary perspective, being part of a cluster can provide cells with several benefits both in terms of survival (e.g. protection) and reproduction (group dispersal). Thus, strategies aimed at inducing cluster dissociation could decrease the metastatic potential of CTCs. However, finding agents or conditions that induce the dissociation of CTC clusters is hampered by the fact that their detection, isolation and propagation remain challenging. Here, we used a mechanistic agent-based model to (a) investigate the response of CTC clusters of various sizes and densities to different challenges-in terms of cell survival and cluster stability, and (b) make predictions as to the combination of factors and parameter values that could decrease the fitness and metastatic potential of CTC clusters. Our model shows that the resilience and stability of CTC clusters are dependent on both their size and density. Also, CTC clusters of distinct sizes and densities respond differently to changes in resource availability, with high-density clusters being least affected. In terms of responses to microenvironmental threats (such as drugs), increasing their intensity is, generally, least effective on high-density clusters. Lastly, we found that combining various levels of resource availability and threat intensity can be more effective at decreasing the survival of CTC clusters than each factor alone. We suggest that the complex effects that cluster density and size showed on both the resilience and stability of the CTC clusters are likely to have significant consequences for their metastatic potential and responses to therapies.

Wound healing across the animal kingdom: Crosstalk between the immune system and the extracellular matrix

Tissue regeneration is widespread in the animal kingdom. To date, key roles for different molecular and cellular programs in regeneration have been described, but the ultimate blueprint for this talent remains elusive. In animals capable of tissue regeneration, one of the most crucial stages is wound healing, whose main goal is to close the wound and prevent infection. In this stage, it is necessary to avoid scar formation to facilitate the activation of the immune system and remodeling of the extracellular matrix, key factors in promoting tissue regeneration. In this review, we will discuss the current state of knowledge regarding the role of the immune system and the interplay with the extracellular matrix to trigger a regenerative response.

Programmable CRISPR-Cas transcriptional activation in bacteria

Programmable gene activation enables fine-tuned regulation of endogenous and synthetic gene circuits to control cellular behavior. While CRISPR-Cas-mediated gene activation has been extensively developed for eukaryotic systems, similar strategies have been difficult to implement in bacteria. Here, we present a generalizable platform for screening and selection of functional bacterial CRISPR-Cas transcription activators. Using this platform, we identified a novel CRISPR activator, dCas9-AsiA, that could activate gene expression by more than 200-fold across genomic and plasmid targets with diverse promoters after directed evolution. The evolved dCas9-AsiA can simultaneously mediate activation and repression of bacterial regulons in E. coli. We further identified hundreds of promoters with varying basal expression that could be induced by dCas9-AsiA, which provides a rich resource of genetic parts for inducible gene activation. Finally, we show that dCas9-AsiA can be ported to other bacteria of clinical and bioindustrial relevance, thus enabling bacterial CRISPRa in more application areas. This work expands the toolbox for programmable gene regulation in bacteria and provides a useful resource for future engineering of other bacterial CRISPR-based gene regulators.

Open-Label Phase 1 Futility Studies of Salsalate and Young Plasma in Progressive Supranuclear Palsy

BACKGROUND

Progressive supranuclear palsy (PSP) is a neurodegenerative disease without approved therapies, and therapeutics are often tried off-label in the hope of slowing disease progression. Results from these experiences are seldom shared, which limits evidence-based knowledge to guide future treatment decisions.

OBJECTIVES

To describe an open-label experience, including safety/tolerability, and longitudinal changes in biomarkers of disease progression in PSP-Richardson's syndrome (PSP-RS) patients treated with either salsalate or young plasma and compare to natural history data from previous multicenter studies.

METHODS

For 6 months, 10 PSP-RS patients received daily salsalate 2,250 mg, and 5 patients received monthly infusions of four units of young plasma. Every 3 months, clinical severity was assessed with the Progressive Supranuclear Palsy Rating Scale (PSPRS), and MRI was obtained for volumetric measurement of midbrain. A range of exploratory biomarkers, including cerebrospinal fluid levels of neurofilament light chain, were collected at baseline and 6 months. Interventional data were compared to historical PSP-RS patients from the davunetide clinical trial and the 4-Repeat Tauopathy Neuroimaging Initiative.

RESULTS

Salsalate and young plasma were safe and well tolerated. PSPRS change from baseline (mean ± standard deviation [SD]) was similar in salsalate (+5.6 ± 9.6), young plasma (+5.0 ± 7.1), and historical controls (+5.6 ± 7.1), and change in midbrain volume (cm3 ± SD) did not differ between salsalate (-0.07 ± 0.03), young plasma (-0.06 ± 0.03), and historical controls (-0.06 ± 0.04). No differences were observed between groups on any exploratory endpoint.

CONCLUSIONS

Neither salsalate nor young plasma had a detectable effect on disease progression in PSP-RS. Focused open-label clinical trials incorporating historical clinical, neuropsychological, fluid, and imaging biomarkers provide useful preliminary data about the promise of novel PSP-directed therapies.

Remodeling adipose tissue inflammasome for type 2 diabetes mellitus treatment: Current perspective and translational strategies

Obesity-associated type 2 diabetes mellitus (T2DM) is characterized by low-grade chronic systemic inflammation that arises primarily from the white adipose tissue. The interplay between various adipose tissue-derived chemokines drives insulin resistance in T2DM and has therefore become a subject of rigorous investigation. The adipocytokines strongly associated with glucose homeostasis include tumor necrosis factor-α, various interleukins, monocyte chemoattractant protein-1, adiponectin, and leptin, among others. Remodeling the adipose tissue inflammasome in obesity-associated T2DM is likely to treat the underlying cause of the disease and bring significant therapeutic benefit. Various strategies have been adopted or are being investigated to modulate the serum/tissue levels of pro- and anti-inflammatory adipocytokines to improve glucose homeostasis in T2DM. These include use of small molecule agonists/inhibitors, mimetics, antibodies, gene therapy, and other novel formulations. Here, we discuss adipocytokines that are strongly associated with insulin activity and therapies that are under investigation for modulation of their levels in the treatment of T2DM.

A step toward engineering thick tissues: Distributing microfibers within 3D printed frames

Microfiber mats for tissue engineering scaffolds support cell growth, but are limited by poor cell infiltration and nutrient transport. Three-dimensional printing, specifically fused deposition modeling (FDM), can rapidly produce customized constructs, but macroscopic porosity resulting from low resolution reduces cell seeding efficiency and prevents the formation of continuous cell networks. Here we describe the fabrication of hierarchical scaffolds that integrate a fibrous microenvironment with the open macropore structure of FDM. Biodegradable tyrosine-derived polycarbonate microfibers were airbrushed iteratively between layers of 3D printed support structure following optimization. Confocal imaging showed layers of airbrushed fiber mats supported human dermal fibroblast growth and extracellular matrix development throughout the scaffold. When implanted subcutaneously, hierarchical scaffolds facilitated greater cell infiltration and tissue formation than airbrushed fiber mats. Fibronectin matrix assembled in vitro throughout the hierarchical scaffold survived decellularization and provided a hybrid substrate for recellularization with mesenchymal stromal cells. These results demonstrate that by combining FDM and airbrushing techniques we can engineer customizable hierarchical scaffolds for thick tissues that support increased cell growth and infiltration.

Association of moderate and vigorous physical activity with incidence of type 2 diabetes and subsequent mortality: 27 year follow-up of the Whitehall II study

AIMS/HYPOTHESIS

This work examined the role of physical activity in the course of diabetes using data spanning nearly three decades. Our first aim was to examine the long-term association of moderate and vigorous physical activity with incidence of type 2 diabetes. Our second aim was to investigate the association of moderate-to-vigorous physical activity post-diabetes diagnosis with subsequent risk of all-cause and cardiovascular disease mortality.

METHODS

A total of 9987 participants from the Whitehall II cohort study free of type 2 diabetes at baseline (1985-1988) were followed for incidence of type 2 diabetes, based on clinical assessments between 1985 and 2016 and linkage to electronic health records up to 31 March 2017. We first examined the association of moderate and vigorous physical activity measured by questionnaire in 1985-1988 (mean age 44.9 [SD 6.0] years; women, 32.7%) with incident type 2 diabetes, using the interval-censored, illness-death model, a competing risk analysis that takes into account both competing risk of death and intermittent ascertainment of diabetes due to reliance on data collection cycles (interval-censored). The second analysis was based on individuals with type 2 diabetes over the follow-up period where we used Cox regression with inverse probability weighting to examine the association of moderate-to-vigorous physical activity after diagnosis of type 2 diabetes with risk of all-cause and cardiovascular disease mortality.

RESULTS

Of the 9987 participants, 1553 developed type 2 diabetes during a mean follow-up of 27.1 (SD 6.3) years. Compared with participants who were inactive in 1985-1988, those who undertook any duration of moderate-to-vigorous physical activity had a lower risk of type 2 diabetes (HR 0.85 [95% CI 0.75, 0.97], p = 0.02; analysis adjusted for sociodemographic, behavioural and health-related factors). In 1026 participants with a diagnosis of type 2 diabetes over the follow-up period, data on moderate-to-vigorous physical activity after diabetes diagnosis were available; 165 all-cause deaths and 55 cardiovascular disease-related deaths were recorded during a mean follow-up of 8.8 (SD 6.1) years. In these participants with diabetes, any duration of moderate-to-vigorous physical activity was associated with lower all-cause mortality (HR 0.61 [95% CI 0.41, 0.93], p = 0.02) while the association with cardiovascular mortality was evident only for physical activity undertaken at or above recommendations (≥2.5 h per week of moderate-to-vigorous physical activity or ≥1.25 h per week of vigorous physical activity; HR 0.40 [95% CI 0.16, 0.96], p = 0.04) in fully adjusted models.

CONCLUSIONS/INTERPRETATION

Moderate-to-vigorous physical activity plays an important role in diabetes, influencing both its incidence and prognosis. A protective effect on incidence was seen for durations of activity below recommendations and a marginal additional benefit was observed at higher durations. Among individuals with type 2 diabetes, any duration of moderate-to-vigorous physical activity was associated with reduced all-cause mortality while recommended durations of physical activity were required for protection against cardiovascular disease-related mortality.

DATA AVAILABILITY

Whitehall II data, protocols and other metadata are available to the scientific community. Please refer to the Whitehall II data sharing policy at https://www.ucl.ac.uk/epidemiology-health-care/research/epidemiology-and-public-health/research/whitehall-ii/data-sharing.

The incidence of orthostatic intolerance after bariatric surgery

AIMS

Every year, over 200 000 individuals undergo bariatric surgery for the treatment of extreme obesity in the United States. Several retrospective studies describe the occurrence of orthostatic intolerance (OI) syndrome after bariatric surgery. However, the incidence of this syndrome remains unknown.

MATERIALS AND METHODS

We used a prospective, de-identified registry of 4547 patients who have undergone bariatric surgery at Vanderbilt to identify cases of new-onset OI. Structured chart reviews were conducted for all subjects who reported new-onset OI post surgery. Cases of OI were confirmed using an operational case definition developed by the Vanderbilt Autonomic Dysfunction Center, and autonomic function tests results were examined for evidence of impaired autonomic function. The cumulative incidence of post-bariatric surgery OI syndrome was estimated using a life table.

RESULTS

Seven hundred forty-one of 4547 (16.3%) patients included in our cohort reported new OI symptoms after surgery. After the chart review, we confirmed the presence of post-bariatric surgery OI syndrome in 85 patients, 14 with severe OI requiring pressor agents. At 5 years post surgery, follow-up is reduced to 15%; the unadjusted 5-year prevalence of OI was 1.9%. The cumulative incidence of OI syndrome adjusted for loss of follow-up was 4.2%. Most OI cases developed during weight-stable months (±5 kg). At the time of identification, 13% of OI cases showed evidence of impaired sympathetic vasoconstrictor activity.

CONCLUSION

OI is frequent in the bariatric population, affecting 4.2% of patients within the first 5 years postoperatively. In 13% of post-bariatric surgery OI patients, there was evidence of impaired sympathetic vasoconstriction activity.

Diaphragm muscle sarcopenia into very old age in mice

Sarcopenia is the age-related decline of skeletal muscle mass and function. Diaphragm muscle (DIAm) sarcopenia may contribute to respiratory complications, a common cause of morbidity and mortality in the elderly. From 6 to 24 months (mo) of age, representing ~100% and ~80% survival in C57BL/6 × 129 male and female mice, there is a significant reduction in DIAm force generation (~30%) and cross-sectional area (CSA) of type IIx and/or IIb muscle fibers (~30%), impacting the ability to perform high force, non-ventilatory behaviors. To date, there is little information available regarding DIAm sarcopenia in very old age groups. The present study examined DIAm sarcopenia in C57BL/6 × 129 male and female mice at 24, 27, and 30 mo, representing ~80%, ~60%, and ~30% survival, respectively. We hypothesized that survival into older ages will show no further worsening of DIAm sarcopenia and functional impairment in 30 mo mice compared to 24 or 27 mo C57BL/6 × 129 mice. Measurements included resting ventilation, transdiaphragmatic pressure (Pdi) generation across a range of motor behaviors, muscle fiber CSA, and proportion of type-identified DIAm fibers. Maximum Pdi and resting ventilation did not change into very old age (from 24 to 30 mo). Type IIx and/or IIb fiber CSA and proportions did not change into very old age. The results of the study support a critical threshold for the reduction in DIAm force and Pdi such that survival into very old age is not associated with evidence of progression of DIAm sarcopenia or impairment in ventilation.

Nuclear localization of the tyrosine kinase BMX mediates VEGFR2 expression

Vascular endothelial growth factor receptors (VEGFRs) are major contributors to angiogenesis and lymphangiogenesis through the binding of VEGF ligands. We have previously shown that the bone marrow tyrosine kinase BMX is critical for inflammatory angiogenesis via its direct transactivation of VEGFR2. In the present study, we show that siRNA-mediated silencing of BMX led to a significant decrease in the total levels of VEGFR2 mRNA and protein, without affecting their stability, in human endothelial cells (ECs). Interestingly, BMX was detected in the nuclei of ECs, and the SH3 domain of BMX was necessary for its nuclear localization. Luciferase assays showed a significant decrease in the Vegfr2 (kdr) gene promoter activity in ECs after BMX silencing, indicating that BMX is necessary for Vegfr2 transcription. In addition, we found that wild-type BMX, but not a catalytic inactive mutant BMX-K445R, promoted Vegfr2 promoter activity and VEGF-induced EC migration and tube sprouting. Mechanistically, we show that the enhancement of Vegfr2 promoter activity by BMX was mediated by Sp1, a transcription factor critical for the Vegfr2 promoter. Loss of BMX significantly reduced Sp1 binding to the Vegfr2 promoter as assayed by chromatin immunoprecipitation assays. Wild-type BMX, but not a kinase-inactive form of BMX, associated with and potentially phosphorylated Sp1. Moreover, a nuclear-targeted BMX (NLS-BMX), but not cytoplasm-localized form (NES-BMX), bound to Sp1 and augmented VEGFR2 expression. In conclusion, we uncovered a novel function of nuclear-localized BMX in regulating VEGFR2 expression and angiogenesis, suggesting that BMX is a therapeutic target for angiogenesis-related diseases.

Selective memory and behavioral alterations after ambient ultrafine particulate matter exposure in aged 3xTgAD Alzheimer's disease mice

BACKGROUND

A growing body of epidemiological literature indicates that particulate matter (PM) air pollution exposure is associated with elevated Alzheimer's disease (AD) risk and may exacerbate AD-related cognitive decline. Of concern is exposure to the ultrafine PM (UFP) fraction (≤100 nm), which deposits efficiently throughout the respiratory tract, has higher rates of translocation to secondary organs, like brain, and may induce inflammatory changes. We, therefore, hypothesize that exposure to UFPs will exacerbate cognitive deficits in a mouse model of AD. The present study assessed alterations in learning and memory behaviors in aged (12.5 months) male 3xTgAD and non-transgenic mice following a 2-week exposure (4-h/day, 4 days/week) to concentrated ambient UFPs using the Harvard ultrafine concentrated ambient particle system (HUCAPS) or filtered air. Beginning one month following exposure, locomotor activity, spatial learning and memory, short-term recognition memory, appetitive motivation, and olfactory discrimination were assessed.

RESULTS

No effects on locomotor activity were found following HUCAPS exposure (number concentration, 1 × 104-4.7 × 105 particles/cm3; mass concentration, 29-132 μg/m3). HUCAPS-exposed mice, independent of AD background, showed a significantly decreased spatial learning, mediated through reference memory deficits, as well as short-term memory deficits in novel object recognition testing. AD mice displayed diminished spatial working memory, potentially a result of olfactory deficits, and short-term memory. AD background modulated HUCAPS-induced changes on appetitive motivation and olfactory discrimination, specifically enhancing olfactory discrimination in NTg mice. Modeling variation in appetitive motivation as a covariate in spatial learning and memory, however, did not support the conclusion that differences in motivation significantly underlie changes in spatial learning and memory.

CONCLUSIONS

A short-term inhalation exposure of aged mice to ambient UFPs at human-relevant concentrations resulted in protracted (testing spanning 1-6.5 months post-exposure) adverse effects on multiple memory domains (reference and short-term memory) independent of AD background. Impairments in learning and memory were present when accounting for potential covariates like motivational changes and locomotor activity. These results highlight the need for further research into the potential mechanisms underlying the cognitive effects of UFP exposure in adulthood.

Neuropathological lesions in the very old: results from a large Brazilian autopsy study

OBJECTIVE

To compare neuropathological correlates of cognitive impairment between very old and younger individuals from a Brazilian clinicopathological study.

METHODS

We assessed the frequency of neuropathological lesions and their association with cognitive impairment (Clinical Dementia Rating scale ≥0.5) in the 80 or over age group compared to younger participants, using logistic regression models adjusted for sex, race and education.

RESULTS

Except for infarcts and siderocalcinosis, all neuropathological lesions were more common in the 80 or over age group (n = 412) compared to 50-79 year olds (n = 677). Very old participants had more than twice the likelihood of having ≥2 neuropathological diagnoses than younger participants (OR = 2.66, 95% CI = 2.03-3.50). Neurofibrillary tangles, infarcts and hyaline arteriolosclerosis were associated with cognitive impairment in the two age groups. Siderocalcinosis was associated with cognitive impairment in the younger participants only, while Lewy body disease was associated with cognitive impairment in the very old only. In addition, we found that the association of infarcts and multiple pathologies with cognitive impairment was attenuated in very old adults (Infarcts: P for interaction = 0.04; and multiple pathologies: P = 0.05). However, the predictive value for the aggregate model with all neuropathological lesions showed similar discrimination in both age groups [Area under Receiver Operating Characteristic curve (AUROC) = 0.778 in younger participants and AUROC = 0.765 in the very old].

CONCLUSION AND RELEVANCE

Despite a higher frequency of neuropathological findings in the very old group, as found in studies with high-income populations, we found attenuation of the effect of infarcts rather than neurofibrillary tangles and plaques as reported previously.

Non-additive effects of ACVR2A in preeclampsia in a Philippine population

BACKGROUND

Multiple interrelated pathways contribute to the pathogenesis of preeclampsia, and variants in susceptibility genes may play a role among Filipinos, an ethnically distinct group with high prevalence of the disease. The objective of this study was to examine the association between variants in maternal candidate genes and the development of preeclampsia in a Philippine population.

METHODS

A case-control study involving 29 single nucleotide polymorphisms (SNPs) in 21 candidate genes was conducted in 150 patients with preeclampsia (cases) and 175 women with uncomplicated normal pregnancies (controls). Genotyping for the GRK4 and DRD1 gene variants was carried out using the TaqMan Assay, and all other variants were assayed using the Sequenom MassARRAY Iplex Platform. PLINK was used for SNP association testing. Multilocus association analysis was performed using multifactor dimensionality reduction (MDR) analysis.

RESULTS

Among the clinical factors, older age (P <  1 × 10-4), higher BMI (P <  1 × 10-4), having a new partner (P = 0.006), and increased time interval from previous pregnancy (P = 0.018) associated with preeclampsia. The MDR algorithm identified the genetic variant ACVR2A rs1014064 as interacting with age and BMI in association with preeclampsia among Filipino women.

CONCLUSIONS

The MDR algorithm identified an interaction between age, BMI and ACVR2A rs1014064, indicating that context among genetic variants and demographic/clinical factors may be crucial to understanding the pathogenesis of preeclampsia among Filipino women.

Neural specialization of phonological and semantic processing in young children

This study aimed to examine early specialization of brain regions for phonological and semantic processing of spoken language in young children. Thirty-five typically developing children aged from 5 to 6 years performed auditory phonological (same sound judgment) and semantic (related meaning judgment) word-level tasks. Using functional magnetic resonance imaging, we examined specialization within the language network, by conducting three levels of analysis. First, we directly compared activation between tasks and found a greater sound judgment as compared to meaning judgment activation in left superior temporal gyrus (STG) and supramarginal gyrus. In contrast, greater meaning judgment as compared to sound judgment task activation was found in left middle temporal gyrus (MTG). Second, we examined the brain-behavior correlations and found that phonological skill was correlated with the task difference in activation in left superior temporal sulcus, whereas semantic skill was correlated with the task difference in activation in left MTG. Third, we compared between two experimental conditions within each task and found a parametric effect in left STG for the sound judgment task, and a parametric effect in left MTG for the meaning judgment task. The results of this study indicate that, by the age of 5-6 years, typically developing children already show some specialization of temporo-parietal brain regions for phonological and semantic processes. However, there were no task differences in the left inferior frontal gyrus suggesting that the frontal cortex may not yet be specialized in this age range, which is consistent with the delayed maturation of the frontal cortex.

Universal microbial diagnostics using random DNA probes

Early identification of pathogens is essential for limiting development of therapy-resistant pathogens and mitigating infectious disease outbreaks. Most bacterial detection schemes use target-specific probes to differentiate pathogen species, creating time and cost inefficiencies in identifying newly discovered organisms. We present a novel universal microbial diagnostics (UMD) platform to screen for microbial organisms in an infectious sample, using a small number of random DNA probes that are agnostic to the target DNA sequences. Our platform leverages the theory of sparse signal recovery (compressive sensing) to identify the composition of a microbial sample that potentially contains novel or mutant species. We validated the UMD platform in vitro using five random probes to recover 11 pathogenic bacteria. We further demonstrated in silico that UMD can be generalized to screen for common human pathogens in different taxonomy levels. UMD's unorthodox sensing approach opens the door to more efficient and universal molecular diagnostics.