Microbes, molecular mimicry and molecules of mood and motivation

The hypothesis proposed is that functional disorders, such as irritable bowel syndrome, chronic fatigue syndrome and anorexia nervosa are caused by auto-antibodies to neuronal proteins induced by molecular mimicry with microbial antigens. The age incidence of these conditions, the marked female excess, increase with economic and technological advance, precipitation by infection, and the paucity of histological changes are all consistent with the hypothesis. It can be tested directly using human sera to search for cross reaction with brain proteins in model systems such as Drosophila melanogaster. The conditions might be amenable to treatment using pooled immunoglobulin. Identification and elimination from the microbial flora of the bacteria that express the cross reacting antigens should be possible

The Drosophila insulin receptor independently modulates lifespan and locomotor senescence

The Insulin/IGF-like signalling (IIS) pathway plays an evolutionarily conserved role in ageing. In model organisms reduced IIS extends lifespan and ameliorates some forms of functional senescence. However, little is known about IIS in nervous system ageing and behavioural senescence. To investigate this role in Drosophila melanogaster, we measured the effect of reduced IIS on senescence of two locomotor behaviours, negative geotaxis and exploratory walking. Two long-lived fly models with systemic IIS reductions (daGAL4/UAS-InRDN (ubiquitous expression of a dominant negative insulin receptor) and d2GAL/UAS-rpr (ablation of insulin-like peptide producing cells)) showed an amelioration of negative geotaxis senescence similar to that previously reported for the long-lived IIS mutant chico. In contrast, exploratory walking in daGAL4/UAS-InRDN and d2GAL/UAS-rpr flies declined with age similarly to controls. To determine the contribution of IIS in the nervous system to these altered senescence patterns and lifespan, the InRDN was targeted to neurons (elavGAL4/UAS-InRDN), which resulted in extension of lifespan in females, normal negative geotaxis senescence in males and females, and detrimental effects on age-specific exploratory walking behaviour in males and females. These data indicate that the Drosophila insulin receptor independently modulates lifespan and age-specific function of different types of locomotor behaviour. The data suggest that ameliorated negative geotaxis senescence of long-lived flies with systemic IIS reductions is due to ageing related effects of reduced IIS outside the nervous system. The lifespan extension and coincident detrimental or neutral effects on locomotor function with a neuron specific reduction (elavGAL4/UAS-InRDN) indicates that reduced IIS is not beneficial to the neural circuitry underlying the behaviours despite increasing lifespan

Introducing Commensal Bacteria from Caenorhabditis elegans to Drosophila melanogaster : Effects on Health, Ageing and Insulin-like Signalling

Background: With the rise of age-related diseases and challenges associated with ageing, there is a growing demand for innovative approaches to promote healthspan. The gut microbiome, essential for health and homeostasis in vertebrates and invertebrates, emerges as a promising avenue for enhancing overall health and addressing age-related disorders. However, little is known about how gut commensals affect host biological processes, let alone what constitutes a healthy gut microbiome. Purpose: Given the shared ecological environments and co-evolutionary history between nematode roundworms and fruit flies, this study introduces Caenorhabditis elegans commensal bacteria (derived from the CeMbio database) to Drosophila melanogaster to probe for bacterial impacts on ageing and interactions with evolutionarily conserved nutrient-sensing pathway—insulin/insulin-like signalling pathway (IIS). Methods: To ascertain successful bacteria colonisation of the fly gut, fly media was adapted for bacteria growth and candidate bacteria were fluorescently transformed to enable direct observation under fluorescence microscopy. Using the optimal experimental conditions and bacterial combination, the impacts of the introduced bacteria on fly health and ageing were evaluated by assaying fly lifespan, exploratory walking behaviour, gut integrity, sleep, neuromuscular function, and fecundity. To gain insights into potential crosstalk between bacteria and IIS, bacteria were also introduced to flies with impaired IIS achieved through either ablating cells that produce Drosophila insulin‐like peptides 2-3 (d2-3GAL4/UAS-rpr) or downregulating insulin receptors expression in serotonergic neurons (trhGAL4/UAS-InRDN). Results: From 16 CeMbio bacteria, 11 bacteria grow on fly media in contingent that antifungals were omitted. Thus, all subsequent experiments utilised additive-free fly media. Out of 24 transformations, 6 new fluorescent bacteria were generated and validated for their correct identity. Three fluorescent bacteria—Ochrobactrum vermis (MYb71-sfGFP), Enterobacter ludwigii (MYb174-dTomato), and Enterobacter cloacae (CEent1-mPlum)— successfully colonised the fly gut. When introduced together, these three bacteria reduced fly median lifespan but increased early-age egg laying, resulting in earlier egg exhaustion. Across life, these bacteria attenuated changes to exploratory walking and sleep behaviour induced by IIS reduction. However, fly gut permeability and neuromuscular function remained unaffected. Conclusions: MYb71-sfGFP, MYb174-dTomato, and CEent1-mPlum may benefit adult flies during early age but be detrimental later as bacterial load increases. Regardless, these bacterial-host interactions crosstalk with IIS to affect complex behaviours like exploratory walking and sleep. These findings provide evidence that the study of ecologically relevant commensal bacteria from C. elegans can be translated onto D. melanogaster to further probe for interactions affecting evolutionarily conserved biological pathways and complex behaviours

An Empirical Charge Transfer Potential with Correct Dissociation Limits

The empirical valence bond (EVB) method [J. Chem. Phys. 52, 1262 (1970)] has always embodied charge transfer processes. The mechanism of that behavior is examined here and recast for use as a new empirical potential energy surface for large-scale simulations. A two-state model is explored. The main features of the model are: (1) Explicit decomposition of the total system electron density is invoked; (2) The charge is defined through the density decomposition into constituent contributions; (3) The charge transfer behavior is controlled through the resonance energy matrix elements which cannot be ignored; and (4) A reference-state approach, similar in spirit to the EVB method, is used to define the resonance state energy contributions in terms of "knowable" quantities. With equal validity, the new potential energy can be expressed as a nonthermal ensemble average with a nonlinear but analytical charge dependence in the occupation number. Dissociation to neutral species for a gas-phase process is preserved. A variant of constrained search density functional theory is advocated as the preferred way to define an energy for a given charge.Comment: Submitted to J. Chem. Phys. 11/12/03. 14 pages, 8 figure

Soil zinc content, groundwater usage, and prostate cancer incidence in South Carolina

Background Prostate cancer (PrCA) incidence in South Carolina (SC) exceeds the national average, particularly among African Americans (AAs). Though data are limited, low environmental zinc exposures and down-regulation of prostatic zinc transporter proteins among AAs may explain, in part, the racial PrCA disparity. Methods Age-adjusted PrCA rates were calculated by census tract. Demographic data were obtained from the 1990 census. Hazardous waste site locations and soil zinc concentrations were obtained from existing federal and state databases. A geographic information system and Poisson regression were used to test the hypothesis that census tracts with reduced soil zinc concentrations, elevated groundwater use, or more agricultural or hazardous waste sites had elevated PrCA risks. Results Census tracts with high groundwater use and low zinc concentrations had higher PrCA rate ratios (RR: 1.270; 95% confidence interval: 1.079, 1.505). This effect was not more apparent in areas populated primarily by AAs. Conclusion Increased PrCA rates were associated with reduced soil zinc concentrations and elevated groundwater use, although this observation is not likely to contribute to SC’s racial PrCA disparity. Statewide mapping and statistical modeling of relationships between environmental factors, demographics, and cancer incidence can be used to screen hypotheses focusing on novel PrCA risk factors

Ketamine Restores Thalamic-Prefrontal Cortex Functional Connectivity in a Mouse Model of Neurodevelopmental Disorder-Associated 2p16.3 Deletion

2p16.3 deletions, involving heterozygous NEUREXIN1 (NRXN1) deletion, dramatically increase the risk of developing neurodevelopmental disorders, including autism and schizophrenia. We have little understanding of how NRXN1 heterozygosity increases the risk of developing these disorders, particularly in terms of the impact on brain and neurotransmitter system function and brain network connectivity. Thus, here we characterize cerebral metabolism and functional brain network connectivity in Nrxn1α heterozygous mice (Nrxn1α+/− mice), and assess the impact of ketamine and dextro-amphetamine on cerebral metabolism in these animals. We show that heterozygous Nrxn1α deletion alters cerebral metabolism in neural systems implicated in autism and schizophrenia including the thalamus, mesolimbic system, and select cortical regions. Nrxn1α heterozygosity also reduces the efficiency of functional brain networks, through lost thalamic “rich club” and prefrontal cortex (PFC) hub connectivity and through reduced thalamic-PFC and thalamic “rich club” regional interconnectivity. Subanesthetic ketamine administration normalizes the thalamic hypermetabolism and partially normalizes thalamic disconnectivity present in Nrxn1α+/− mice, while cerebral metabolic responses to dextro-amphetamine are unaltered. The data provide new insight into the systems-level impact of heterozygous Nrxn1α deletion and how this increases the risk of developing neurodevelopmental disorders. The data also suggest that the thalamic dysfunction induced by heterozygous Nrxn1α deletion may be NMDA receptor-dependent

Understanding exogenous factors and biological mechanisms for cognitive frailty: A multidisciplinary scoping review

Cognitive frailty (CF) is the conjunction of cognitive impairment without dementia and physical frailty. While predictors of each element are well-researched, mechanisms of their co-occurrence have not been integrated, particularly in terms of relationships between social, psychological, and biological factors. This interdisciplinary scoping review set out to categorise a heterogenous multidisciplinary literature to identify potential pathways and mechanisms of CF, and research gaps. Studies were included if they used the definition of CF OR focused on conjunction of cognitive impairment and frailty (by any measure), AND excluded studies on specific disease populations, interventions, epidemiology or prediction of mortality. Searches used Web of Science, PubMed and Science Direct. Search terms included “cognitive frailty” OR ((“cognitive decline” OR “cognitive impairment”) AND (frail*)), with terms to elicit mechanisms, predictors, causes, pathways and risk factors. To ensure inclusion of animal and cell models, keywords such as “behavioural” or “cognitive decline” or “senescence”, were added. 206 papers were included. Descriptive analysis provided high-level categorisation of determinants from social and environmental through psychological to biological. Patterns distinguishing CF from Alzheimer's disease were identified and social and psychological moderators and mediators of underlying biological and physiological changes and of trajectories of CF development were suggested as foci for further research

Training the Workforce to Conduct Embedded Pragmatic Clinical Trials to Improve Care for People Living with Dementia and Their Caregivers

The National Institute on Aging IMbedded Pragmatic Alzheimer’s Disease and Alzheimer’s Disease-Related Dementias Clinical Trials (IMPACT) Collaboratory serves as a national resource for the conduct of embedded pragmatic clinical trials to improve the care of people living with dementia (PLWD) in partnership with the healthcare systems that serve them. Inherent in this objective is the need to train and support a cadre of investigators prepared to conduct this work now and in the future. The Training Core of the IMPACT Collaboratory supports the training of investigators to become experts in this field through three objectives: (1) curricula development and dissemination; (2) network generation and navigation; and (3) a career development award program. The innovative approach of the Training Core will require developing content and providing training experiences that recognize the unique challenges of research at the intersection of health systems, pragmatic trials, and PLWD and their caregivers. Ultimately, we seek to build the nation’s capacity to conduct research that bridges the gaps between efficacy studies to effectiveness research to implementation science. Although foundational resources in the methods of each of these areas are already available, few actually focus on pragmatic trials embedded within healthcare systems that focus on PLWD. To bring new interventions for PLWD from efficacy to widespread implementation, researchers must build diffusability, adaptability, heterogeneity, and scalability into the design of the intervention. In achieving these objectives, the Training Core will utilize the network of investigators, institutions, and stakeholders represented in the IMPACT Collaboratory

VISTA Deficiency Attenuates Antibody-induced Arthritis and Alters Macrophage Gene Expression in Response to Simulated Immune Complexes

In addition to activated T cells, the immune checkpoint inhibitor “V domain-containing Ig suppressor of T-cell activation” (VISTA) is expressed by myeloid cell types, including macrophages and neutrophils. The importance of VISTA expression by myeloid cells to antibody-induced arthritis and its potential for relevance in human disease was evaluated. Methods: VISTA was immunolocalized in normal and arthritic human synovial tissue sections and synovial tissue lysates were subjected to western blot analysis. The collagen antibody-induced arthritis model (CAIA) was performed with DBA/1 J mice treated with antibodies against VISTA and with VISTA-deficient mice (V-KO). Total mRNA from arthritic joints, spleens, and cultured macrophages was analyzed with NanoString arrays. Cytokines secreted by splenic inflammatory macrophages were determined. In-vitro chemotaxis and signal transduction assays were performed with cultured macrophages. Results: VISTA protein was localized to synovial membrane cells, neutrophils, and scattered cells in lymphocyte-rich foci and was detected by western blot analysis in normal synovium and synovium from rheumatoid arthritis patients. Deficiency of VISTA or treatment of mice with anti-VISTA monoclonal antibodies attenuated CAIA. Joint damage and MMP-3 expression were significantly reduced in V-KO mice. Surface expression of C5a receptor was reduced on monocytes, neutrophils, and cultured macrophages from V-KO. Upon Fc receptor engagement in vitro, gene expression by V-KO macrophages was altered profoundly compared to WT, including a significant induction of IL-1 receptor antagonist (IL1rn). Conclusions: VISTA expression supports immune-complex inflammation in CAIA and VISTA is expressed in human synovium. VISTA supports optimal responses to C5a and modulates macrophage responses to immune complexes