Natural variation in gene expression and viral susceptibility revealed by neural progenitor cell villages.

Human genome variation contributes to diversity in neurodevelopmental outcomes and vulnerabilities; recognizing the underlying molecular and cellular mechanisms will require scalable approaches. Here, we describe a "cell village" experimental platform we used to analyze genetic, molecular, and phenotypic heterogeneity across neural progenitor cells from 44 human donors cultured in a shared in vitro environment using algorithms (Dropulation and Census-seq) to assign cells and phenotypes to individual donors. Through rapid induction of human stem cell-derived neural progenitor cells, measurements of natural genetic variation, and CRISPR-Cas9 genetic perturbations, we identified a common variant that regulates antiviral IFITM3 expression and explains most inter-individual variation in susceptibility to the Zika virus. We also detected expression QTLs corresponding to GWAS loci for brain traits and discovered novel disease-relevant regulators of progenitor proliferation and differentiation such as CACHD1. This approach provides scalable ways to elucidate the effects of genes and genetic variation on cellular phenotypes.

Dementia literacy of racially minoritized people in a Chinese society: a qualitative study among South Asian migrants in Hong Kong.

OBJECTIVES: Research on dementia literacy in Chinese societies is still emerging, and this is especially the case among racially minoritized groups. The present study explored the knowledge, causal beliefs, and help-seeking behaviors of South Asian migrants in Hong Kong about dementia. It also investigated existing community barriers related to dementia knowledge and help-seeking. DESIGN: We conducted a qualitative study from a purposive sample of 38 older people and family caregivers from India, Pakistan, and Nepal who lived in Hong Kong. Focus groups and individual in-depth interviews were used to gather information, while thematic analysis was employed to analyze the data. RESULTS: Five main themes were identified: normalization with stigmatization of dementia; spiritual and psychosocial attributions of dementia; familial responsibility despite potential caregiving burden; uncertainties versus openness to professional care; and barriers and opportunities in dementia literacy. Ethnic minorities recognized dementia as a disease of normal aging or a mental disorder. They also perceived spiritual and psychosocial factors as their main causes. While participants recognized the potential burden of dementia caregiving, families were their first point of help-seeking, as many of them expressed contrasting feelings of confidence or doubt toward professional services. Utilization of health education strategies, together with collaboration with community leaders, could address the barriers to dementia literacy. CONCLUSIONS: This is the first study to explore how ethnic minorities in Asia perceive dementia and its related help-seeking behaviors in their communities. South Asian migrants in Hong Kong have a limited understanding of dementia and may experience delays in obtaining relevant community services. While culture influenced their knowledge, health education may address their misperceptions and help-seeking behaviors toward dementia. Culture- and language-specific programs could also improve dementia knowledge and health service access.

Growing Old as a Member of an Ethnic Minority in Hong Kong: Implications for an Inclusive Long-Term Care Policy Framework.

Hong Kong is experiencing significant demographic changes as a result of rapid population aging and immigration. Anecdotal evidence suggests that ethnic minorities, in particular aged members of South Asian ethnic minorities, face significant and diverse obstacles in accessing services important to their general welfare. This study is the first systematic attempt to explore the long-term care needs of Nepalese older adults in Hong Kong and the barriers they face in accessing long-term care services. Data were obtained through semi-structured interviews with 30 Nepalese older adults. We found that Nepalese older adults have similar physical and psychosocial needs as those of their local Chinese counterparts. However, participants face a range of structural, knowledge, and attitudinal barriers that together deter them from accessing long-term care services, despite their right to do so. Policy recommendations to mitigate these barriers are given, with reference to the World Health Organization's Age-Friendly Cities Framework.

A deleterious Nav1.1 mutation selectively impairs telencephalic inhibitory neurons derived from Dravet Syndrome patients.

Dravet Syndrome is an intractable form of childhood epilepsy associated with deleterious mutations in SCN1A, the gene encoding neuronal sodium channel Nav1.1. Earlier studies using human induced pluripotent stem cells (iPSCs) have produced mixed results regarding the importance of Nav1.1 in human inhibitory versus excitatory neurons. We studied a Nav1.1 mutation (p.S1328P) identified in a pair of twins with Dravet Syndrome and generated iPSC-derived neurons from these patients. Characterization of the mutant channel revealed a decrease in current amplitude and hypersensitivity to steady-state inactivation. We then differentiated Dravet-Syndrome and control iPSCs into telencephalic excitatory neurons or medial ganglionic eminence (MGE)-like inhibitory neurons. Dravet inhibitory neurons showed deficits in sodium currents and action potential firing, which were rescued by a Nav1.1 transgene, whereas Dravet excitatory neurons were normal. Our study identifies biophysical impairments underlying a deleterious Nav1.1 mutation and supports the hypothesis that Dravet Syndrome arises from defective inhibitory neurons.

A comparison of non-integrating reprogramming methods.

Human induced pluripotent stem cells (hiPSCs) are useful in disease modeling and drug discovery, and they promise to provide a new generation of cell-based therapeutics. To date there has been no systematic evaluation of the most widely used techniques for generating integration-free hiPSCs. Here we compare Sendai-viral (SeV), episomal (Epi) and mRNA transfection mRNA methods using a number of criteria. All methods generated high-quality hiPSCs, but significant differences existed in aneuploidy rates, reprogramming efficiency, reliability and workload. We discuss the advantages and shortcomings of each approach, and present and review the results of a survey of a large number of human reprogramming laboratories on their independent experiences and preferences. Our analysis provides a valuable resource to inform the use of specific reprogramming methods for different laboratories and different applications, including clinical translation.

Hydrogen-bonded His93 as a sensitive probe for identifying inhibitors of the endocannabinoid transport protein FABP7.

The human brain FABP (FABP7) has been shown to be an intracellular carrier protein that can significantly potentiate the uptake of the endocannabinoid anandamide. For this reason, there is a great interest in the discovery and development of FABP7 inhibitors for treating stress, pain, inflammation, and drug abuse. We found that in the (1) H-NMR spectrum of the protein, a well-separated downfield resonance arising from the hydrogen-bonded His93 side chain is very sensitive to ligand binding. Using this characteristic spectral marker together with another well-resolved upfield resonance from the side chain of Val84, we have identified that an adipocyte FABP (FABP4) inhibitor BMS309403 also binds tightly to FABP7. Our data demonstrated that this unique His93 downfield resonance can be used as a sensitive probe for rapidly and unambiguously identifying novel high-affinity FABP7 ligands. The findings should help accelerate the discovery of potential drug leads for the modulation of endocannabinoid transport.

Effects of inorganic nitrogen enrichment on mosquitoes (Diptera: Culicidae) and the associated aquatic community in constructed treatment wetlands.

Ammonium nitrogen (NH4-N) is a significant component of municipal and agricultural wastewaters, and nitrogen reduction is an important use of constructed treatment wetlands. The effects of ammonium nitrogen enrichment on resources of larval mosquitoes, larval mosquito abundance, adult mosquito production, and the abundance of related wetland organisms were examined in 0.1-ha replicate treatment wetlands. The hypothesis of a bottom-up effect induced by ammonium addition was not supported by bacterial abundance, mean bacterial cell size, or algal biomass in the water column. There was, however, a significant negative correlation between bacterial cell length and Culex tarsalis Coquillett (Diptera: Culicidae) larval abundance 1 wk later in wetlands enriched with ammonium nitrogen. Larval mosquito (Culex spp.) abundance in southern California wetlands enriched with NH4-N (mean approximately equal to 3 mg/liter) was significantly greater than in control wetlands at ambient nitrogen levels (8.3 mg NO3-N/liter, 0.1 mg NH4-N/liter). Adult mosquito production was nine-fold greater and chironomid larvae were significantly more abundant in wetlands enriched with NH4-N than in controls but other censused taxa exhibited no significant trends. Mosquitofish, Gambusia affinis (Baird & Girard), abundance was significantly reduced in enriched wetlands, but other potential mosquito predators were not significantly affected by ammonium enrichment.