An integrated toolkit for human microglia functional genomics.

BACKGROUND: Microglia, the brain's resident immune cells, play vital roles in brain development, and disorders like Alzheimer's disease (AD). Human iPSC-derived microglia (iMG) provide a promising model to study these processes. However, existing iMG generation protocols face challenges, such as prolonged differentiation time, lack of detailed characterization, and limited gene function investigation via CRISPR-Cas9. METHODS: Our integrated toolkit for in-vitro microglia functional genomics optimizes iPSC differentiation into iMG through a streamlined two-step, 20-day process, producing iMG with a normal karyotype. We confirmed the iMG's authenticity and quality through single-cell RNA sequencing, chromatin accessibility profiles (ATAC-Seq), proteomics and functional tests. The toolkit also incorporates a drug-dependent CRISPR-ON/OFF system for temporally controlled gene expression. Further, we facilitate the use of multi-omic data by providing online searchable platform that compares new iMG profiles to human primary microglia: https://sherlab.shinyapps.io/IPSC-derived-Microglia/ . RESULTS: Our method generates iMG that closely align with human primary microglia in terms of transcriptomic, proteomic, and chromatin accessibility profiles. Functionally, these iMG exhibit Ca2 + transients, cytokine driven migration, immune responses to inflammatory signals, and active phagocytosis of CNS related substrates including synaptosomes, amyloid beta and myelin. Significantly, the toolkit facilitates repeated iMG harvesting, essential for large-scale experiments like CRISPR-Cas9 screens. The standalone ATAC-Seq profiles of our iMG closely resemble primary microglia, positioning them as ideal tools to study AD-associated single nucleotide variants (SNV) especially in the genome regulatory regions. CONCLUSIONS: Our advanced two-step protocol rapidly and efficiently produces authentic iMG. With features like the CRISPR-ON/OFF system and a comprehensive multi-omic data platform, our toolkit equips researchers for robust microglial functional genomic studies. By facilitating detailed SNV investigation and offering a sustainable cell harvest mechanism, the toolkit heralds significant progress in neurodegenerative disease drug research and therapeutic advancement.

A pharmacological toolkit for human microglia identifies Topoisomerase I inhibitors as immunomodulators for Alzheimer's disease.

While efforts to identify microglial subtypes have recently accelerated, the relation of transcriptomically defined states to function has been largely limited to in silico annotations. Here, we characterize a set of pharmacological compounds that have been proposed to polarize human microglia towards two distinct states - one enriched for AD and MS genes and another characterized by increased expression of antigen presentation genes. Using different model systems including HMC3 cells, iPSC-derived microglia and cerebral organoids, we characterize the effect of these compounds in mimicking human microglial subtypes in vitro. We show that the Topoisomerase I inhibitor Camptothecin induces a CD74high/MHChigh microglial subtype which is specialized in amyloid beta phagocytosis. Camptothecin suppressed amyloid toxicity and restored microglia back to their homeostatic state in a zebrafish amyloid model. Our work provides avenues to recapitulate human microglial subtypes in vitro, enabling functional characterization and providing a foundation for modulating human microglia in vivo.

Using Machine Learning to Determine a Suitable Patient Population for Anakinra for the Treatment of COVID-19 Under the Emergency Use Authorization.

A randomized, double-blind, placebo-controlled study (SAVEMORE trial) provided data to support an Emergency Use Authorization (EUA) of anakinra in hospitalized adults with positive results of direct severe acute respiratory syndrome-coronavirus 2 viral testing with pneumonia requiring supplemental oxygen (low- or high-flow oxygen) who are at risk of progressing to severe respiratory failure and likely to have an elevated plasma soluble urokinase plasminogen activator receptor (suPAR). Currently, the suPAR assay is not commercially available in the United States. An alternative method was needed to identify patients that best reflect the population in the clinical trial selected based on suPAR level ≥ 6 ng/mL at baseline. A machine learning approach based on data from the SAVEMORE trial was used to develop a scoring rule to identify patients who are likely to have a suPAR level ≥ 6 ng/mL at baseline. External validation of the scoring rule was conducted with data from a different trial (SAVE). This clinical scoring rule with high positive predictive value, high specificity, reasonable sensitivity, and biological relevance is expected to identify patients who are likely to have an elevated suPAR level ≥ 6 ng/mL at baseline. As such, it is included in the EUA to identify patients that fall within the authorized population for whom the known and potential benefits outweigh the known and potential risks of anakinra.

Regulatory T cell-derived IL-1Ra suppresses the innate response to respiratory viral infection.

Regulatory T (Treg) cell modulation of adaptive immunity and tissue homeostasis is well described; however, less is known about Treg cell-mediated regulation of the innate immune response. Here we show that deletion of ST2, the receptor for interleukin (IL)-33, on Treg cells increased granulocyte influx into the lung and increased cytokine production by innate lymphoid and γδ T cells without alteration of adaptive immunity to influenza. IL-33 induced high levels of the interleukin-1 receptor antagonist (IL-1Ra) in ST2+ Treg cells and deletion of IL-1Ra in Treg cells increased granulocyte influx into the lung. Treg cell-specific deletion of ST2 or IL-1Ra improved survival to influenza, which was dependent on IL-1. Adventitial fibroblasts in the lung expressed high levels of the IL-1 receptor and their chemokine production was suppressed by Treg cell-produced IL-1Ra. Thus, we define a new pathway where IL-33-induced IL-1Ra production by tissue Treg cells suppresses IL-1-mediated innate immune responses to respiratory viral infection.

Neighborhood built environments and cognition in later life.

Objectives: Maintaining good cognition is crucial in later life. However, most existing research has focused on individual factors impacting cognition, and few studies have investigated the association between neighborhood built environment and older adults' cognition. This study examined the association between neighborhood built environment and cognition among community-dwelling older adults and identified variations in this association between different age groups in the older population.Methods: Data were derived from a cross-sectional survey of 1873 people aged 65 years and above in Hong Kong. We merged individual data from the survey with neighborhood built environment data based on community auditing and geographical information system. After controlling for individual covariates, we used multivariable linear regression to examine the association between neighborhood built environment and cognition.Results: Residents aged 80 and younger in neighborhoods with a higher land-use mix and more public transport terminals exhibited better cognition. Only the number of community centers in a neighborhood was positively associated with cognition for people older than 80.Conclusion: The built environment creates diverse impacts on different age groups among older adults. Our findings provide useful information for urban planners and policymakers for planning community facilities and built environments that consider the needs of different age groups within the older population.

Spatial uncertainty and environment-health association: An empirical study of osteoporosis among "old residents" in public housing estates across a hilly environment.

BACKGROUND: Built environment can influence physical conditions of older adults (e.g. osteoporosis). However, traditional methods using 2-dimensional circular buffer as a spatial structure to measure neighbourhood effect may create bias in health estimation, especially for the hilly and compact environment across low-income neighbourhoods (e.g. public housing estates). METHODS: We evaluated the environmental influences on self-reported osteoporosis among "old residents" (age≥65) in Hong Kong (n = 2077). Twelve public housing estates across hilly neighbourhoods in Hong Kong were selected as study sites. A cross-validated approach was developed to evaluate four spatial structures (2D circular, 2D service area, 3D circular, 3D service area). To determine problems of spatial uncertainty, we compared odds ratios (OR) and differences in effect sizes from models using different spatial structures. When all adjusted models achieve significant results based on 95% confidence intervals (CI) and with all positive/negative ORs, this study reported to have reached "a result with consistency". Results from the 3D service area were then used to explain the environment-health relationship. RESULTS: Different spatial structures can yield different results. Particularly, circular buffers overestimated environmental effects on self-reported osteoporosis. Overestimated measures were related to walkability and accessibility but not greenery. Specifically, results from the 3D service area showed that more public space and health facilities within a walkable distance (500 m) from a location of subject's residence were negatively associated with self-reported osteoporosis (adjusted ORs: 0.44 [0.29, 0.66]; 0.94 [0.90, 0.99]). However, more major transport facilities at the immediate distance from residence (200 m) was positively associated with self-reported osteoporosis (adjusted OR: 1.11 [1.01, 1.23]). CONCLUSIONS: Physical conditions (e.g. osteoporosis) of older adults living in a hilly neighbourhood could be driven by walking behaviours. It is necessary to include local terrain and road network to define a walkable neighbourhood for environment-health estimations to minimize spatial bias.

Neighbourhood physical environment, intrinsic capacity, and 4-year late-life functional ability trajectories of low-income Chinese older population: A longitudinal study with the parallel process of latent growth curve modelling.

BACKGROUND: Knowledge of how intrinsic capacity (IC) and neighbourhood physical environment shape functional ability (FA) trajectories in later life remains understudied. We investigated four-year trajectories of IC and their impact on FA trajectories and the association between neighbourhood physical environment and FA trajectories among community-dwelling older adults in Hong Kong, China. METHODS: We conducted a four-wave longitudinal study from 2014 to 2017 in Hong Kong with 2,081 adults aged 65 and above. FA was assessed by The Chinese Lawton Instrumental Activities of Daily Living Scale. We used cognition, affect, locomotion, sensory capacity, and vitality to capture the multiple domains of IC. Neighbourhood physical environment attributes included green space, land use diversity, and availability of facilities, assessed within 200- and 500-meter buffers of respondents' homes. We used the parallel process of latent growth curve model. FINDINGS: IC (Unstandardized coefficient, ß = -0.02, p<0.001) and FA (ß = -0.20, p<0.001) each decreased significantly over time. Individuals with declines in IC experienced a faster decline in FA over time. Green space within a 200-meter buffer (ß = 1.15, p = 0.023), the number of leisure (ß = 0.03, p = .0.043) and public transport (ß = 0.08, p = .0.003) facilities within a 500-meter buffer slowed the rate of FA decline. INTERPRETATION: The level of FA decreased over time in later life. Changes in IC shaped FA trajectories. Increased residential green space and the number of leisure and public transport facilities in the neighbourhood may help slow FA decline over time. FUNDING: The Hong Kong Housing Society.

Longitudinal associations between neighbourhood physical environments and depressive symptoms of older adults in Hong Kong: The moderating effects of terrain slope and declining functional abilities.

Little is known about the accumulative impacts of neighbourhood physical environments on older adults' depressive symptoms over time. Based on a cohort study of 2081 older adults in Hong Kong, this study examined longitudinal relationships between neighbourhood physical environments and depressive symptoms among older adults, with a particular focus on the moderating effects of terrain slope and individual functional ability using latent growth curve modelling. Results indicated that the availability of community centres and passive leisure facilities reduced depressive symptoms over time. The protective effects of residential surrounding greenness on depressive symptoms among older adults differed by the terrain slope types. Longitudinal associations between neighbourhood physical environments and depressive symptoms varied between older adults with and without functional limitations. This study has implications for the Ecological Theory of Ageing by identifying the dynamic interplay of environment demands and individual functional ability. Planning policies for building age-friendly neighbourhoods are discussed.

Neighborhood Built Environment and Late-Life Depression: A Multilevel Path Analysis in a Chinese Society.

OBJECTIVES: Neighborhood built environments (BEs) are increasingly recognized as being associated with late-life depression. However, their pathways are still understudied. This study investigates the mediating effects of physical and social activities (PA and SA) and functional ability (FA) in the relationships between BEs and late-life depression. METHODS: We conducted a cross-sectional analysis with data from 2,081 community-dwellers aged 65 years and older in Hong Kong in 2014. Two road-network-based service area buffers (200- and 500-m buffers) adjusted by terrain and slope from participants' residences were created to define the scope of neighborhoods. BEs comprised population density in District Council Constituency Areas, urban greenness, land-use diversity, and neighborhood facilities within 200- and 500-m buffers. Multilevel path analysis models were used. RESULTS: More urban greenness within both buffers and more commercial facilities within a 500-m buffer were directly associated with fewer depressive symptoms. SA mediated the relationship between the number of community facilities and depressive symptoms within a 200-m buffer. Neighborhood urban greenness and the number of commercial facilities had indirect associations on depressive symptoms within a 500-m buffer, which were mediated by FA. DISCUSSION: Our findings have implications for the ecological model of aging. The mediating effects of SA and FA underscore the importance of promoting active social lifestyles and maintaining FA for older adults' mental health in high-density cities. Policy implications on how to build age-friendly communities are discussed.

The Contribution of Sense of Community to the Association Between Age-Friendly Built Environment and Health in a High-Density City: A Cross-Sectional Study of Middle-Aged and Older Adults in Hong Kong.

Sense of community may be shaped by the quality of the physical environment and has potential health implications. Based on a survey of 2,247 community-dwelling middle-aged and older adults living in Hong Kong, we tested the mediation effect of sense of community on the relationship between the quality of the built environment and physical and mental health using path analysis. The quality of the built environment was indicated by the age-friendliness of outdoor spaces and buildings. No direct association was found between the built environment and health outcomes, although age-friendly outdoor spaces were associated with better mental health. Sense of community mediated 14% of the total effect between outdoor spaces and mental health and 44.8% of the total effect between buildings and physical health, underscoring the importance of accommodating the social needs of middle-aged and older people in urban development in high-density cities.

Older Adults' Perceptions of Age-friendliness in Hong Kong.

BACKGROUND AND OBJECTIVES: There is little understanding about how rapid urban development has affected the extent to which communities are able to optimize health and participation opportunities for older adults in Hong Kong. Our objective was to examine what older residents perceive to be the shortcomings of their communities in meeting their psychosocial and physical needs as they age. RESEARCH DESIGN AND METHODS: In reference to the WHO Age-Friendly Cities Project Methodology: Vancouver Protocol, we conducted nine focus groups comprising 65 participants for an Age-Friendly City baseline assessment in two districts in Hong Kong, China. Participants were asked to share their views on their respective district of residence, and identify aspects of the city they found unfriendly. Data generated from interviews were analyzed using thematic analysis. RESULTS: Five of the following key themes were identified: the failure of public transportation to cater to the needs of older adults; a lack of public space for recreation and socializing; diminishing human interactions in welfare services; physical and financial challenges relating to housing; and workplace discrimination against older adults. DISCUSSION AND IMPLICATIONS: These findings underscore the importance of prioritizing the social welfare of older adults in building a more inclusive and age-friendly city. They also highlight the difficulties in fostering an inclusive environment while ensuring efficiency and profit maximization.