Single-cell mapping of lipid metabolites using an infrared probe in human-derived model systems.

Understanding metabolic heterogeneity is the key to uncovering the underlying mechanisms of metabolic-related diseases. Current metabolic imaging studies suffer from limitations including low resolution and specificity, and the model systems utilized often lack human relevance. Here, we present a single-cell metabolic imaging platform to enable direct imaging of lipid metabolism with high specificity in various human-derived 2D and 3D culture systems. Through the incorporation of an azide-tagged infrared probe, selective detection of newly synthesized lipids in cells and tissue became possible, while simultaneous fluorescence imaging enabled cell-type identification in complex tissues. In proof-of-concept experiments, newly synthesized lipids were directly visualized in human-relevant model systems among different cell types, mutation status, differentiation stages, and over time. We identified upregulated lipid metabolism in progranulin-knockdown human induced pluripotent stem cells and in their differentiated microglia cells. Furthermore, we observed that neurons in brain organoids exhibited a significantly lower lipid metabolism compared to astrocytes.

The landscape of the immunoglobulin repertoire in endemic pemphigus foliaceus.

Introduction: Primarily driven by autoreactive B cells, pemphigus foliaceus (PF) is an uncommon autoimmune blistering skin disease of sporadic occurrence worldwide. However, PF reaches a prevalence of 3% in the endemic areas of Brazil, the highest ever registered for any autoimmune disease, which indicates environmental factors influencing the immune response in susceptible individuals. We aimed to provide insights into the immune repertoire of patients with PF living in the endemic region of the disease, compared to healthy individuals from the endemic region and a non-endemic area. Methods: We characterized the B-cell repertoire in i) nontreated patients (n=5); ii) patients under immunosuppressive treatment (n=5); iii) patients in remission without treatment (n=6); and two control groups iv) from the endemic (n=6) and v) non-endemic areas in Brazil (n=4). We used total RNA extracted from peripheral blood mononuclear cells and performed a comprehensive characterization of the variable region of immunoglobulin heavy chain (IGH) in IgG and IgM using next-generation sequencing. Results: Compared to individuals from a different area, we observed remarkably lower clonotype diversity in the B-cell immune repertoire of patients and controls from the endemic area (p < 0.02), suggesting that the immune repertoire in the endemic area is under geographically specific and intense environmental pressure. Moreover, we observed longer CDR3 sequences in patients, and we identified differential disease-specific usage of IGHV segments, including increased IGHV3-30 and decreased IGHV3-23 in patients with active disease (p < 0.04). Finally, our robust network analysis discovered clusters of CDR3 sequences uniquely observed in patients with PF. Discussion: Our results indicate that environmental factors, in addition to disease state, impact the characteristics of the repertoire. Our findings can be applied to further investigation of the environmental factors that trigger pemphigus and expand the knowledge for identifying new targeted and more effective therapies.

Social Stigma: A Systematic Review of Cognitive Insights from Behavioral Economics (1940-2019).

There are minority and stigmatized groups who face particular challenges to their full participation in society. This study's objective was to conduct a systematic review to determine theoretical and methodological underpinnings in behavioral economics that explain how stigmatization emerges within the relationship processes and social structures of individuals. Data from 1940 to 2019 were sourced from 12 relevant electronic databases such as Scopus and Web of Science. Following PRISMA guidelines for systematic reviews, 26 studies out of 3459 met the inclusion criteria. Most of the studies applied experimental economics and were published between 2002 and 2018. Overall, the articles focus their research on the experiences of discrimination based on stereotypes and test their hypotheses through economic games. The data synthesis seems to reveal weak conceptual clarity, circular reasoning, and a hint of the problem of infinite regress. Thus, these issues open new and exciting avenues for future research to explore via an array of experimental applications.

Existen grupos minoritarios y estigmatizados que enfrentan retos particulares para lograr su completa participación en sociedad. El objetivo de este estudio fue conducir una revisión sistemática para determinar los cimientos teóricos y metodológicos en economía del comportamiento que explican cómo surge la estigmatización dentro de los procesos de relacionamiento y estructuras sociales de los individuos. Los datos abarcan el período de 1940 a 2019 y se obtuvieron de 12 bases de datos electrónicas relevantes, tales como Scopus y Web of Science. Siguiendo la guía de PRISMA para revisiones sistemáticas, 26 estudios de 3459 cumplieron con los criterios de inclusión. La mayoría de los estudios aplicó economía experimental y fueron publicados entre 2002 y 2018. En general, los artículos enfocan su investigación en experiencias de discriminación basadas en estereotipos y prueban sus hipótesis a través de juegos económicos. La síntesis de los datos parece revelar una débil claridad conceptual, razonamiento circular y un atisbo del problema de regresión infinita. Lo anterior abre nuevas y emocionantes vías de investigación futura para explorar a través de una variedad de aplicaciones experimentales.

Genetic association and differential expression of HLAComplexGroup lncRNAs in pemphigus.

BACKGROUND: Pemphigus is a group of bullous diseases characterized by acantholysis and skin blisters. As for other autoimmune diseases, the strongest genetic associations found so far for pemphigus foliaceus (PF) and vulgaris (PV) are with alleles of HLA genes. However, apart from protein-coding genes, the MHC region includes a set of poorly explored long non-coding RNA (lncRNA) genes, the HLA complex group (HCG). OBJECTIVES: To investigate if HCG lncRNA alleles are associated with pemphigus susceptibility. METHODS AND RESULTS: We analyzed SNPs in 13 HCG lncRNA genes, both in PV (Germany: 241 patients; 1,188 controls) and endemic PF (Brazil: 227 patients; 194 controls), applying multivariate logistic regression. We found 55 associations with PV (pcorr < 0.01) and nine with endemic PF (pcorr < 0.05), the majority located in TSBP1-AS1 (which includes HCG23) and HCG27 lncRNA genes, independently of HLA alleles previously associated with pemphigus. The association of TSBP1-AS1 rs3129949*A allele was further replicated in sporadic PF (p = 0.027, OR = 0.054; 75 patients and 150 controls, all from Germany). Next, we evaluated the expression levels of TSBP1-AS1, TSBP1, HCG23, and HCG27 in blood mononuclear cells of Brazilian patients and controls. HCG27 was upregulated in endemic PF (p = 0.035, log2 FC = 1.3), while TSBP1-AS1 was downregulated in PV (p = 0.029, log2 FC = -1.29). The same expression patterns were also seen in cultured keratinocytes stimulated with IgG antibodies from patients and controls from Germany. TSBP1 mRNA levels were also decreased in endemic PF blood cells (p = 0.042, log2 FC = -2.14). TSBP1-AS1 and HCG27 were also observed downregulated in CD19+ cells of endemic PF (p < 0.01, log2 FC = -0.226 and -0.46 respectively). CONCLUSIONS: HCG lncRNAs are associated with susceptibility to pemphigus, being TSBP1-AS1 and HCG27 also differentially expressed in distinct cell populations. These results suggest a role for HCG lncRNAs in pemphigus autoimmunity.

Pathogenic Tau Impairs Axon Initial Segment Plasticity and Excitability Homeostasis.

Dysregulation of neuronal excitability underlies the pathogenesis of tauopathies, including frontotemporal dementia (FTD) with tau inclusions. A majority of FTD-causing tau mutations are located in the microtubule-binding domain, but how these mutations alter neuronal excitability is largely unknown. Here, using CRISPR/Cas9-based gene editing in human pluripotent stem cell (iPSC)-derived neurons and isogenic controls, we show that the FTD-causing V337M tau mutation impairs activity-dependent plasticity of the cytoskeleton in the axon initial segment (AIS). Extracellular recordings by multi-electrode arrays (MEAs) revealed that the V337M tau mutation in human neurons leads to an abnormal increase in neuronal activity in response to chronic depolarization. Stochastic optical reconstruction microscopy of human neurons with this mutation showed that AIS plasticity is impaired by the abnormal accumulation of end-binding protein 3 (EB3) in the AIS submembrane region. These findings expand our understanding of how FTD-causing tau mutations dysregulate components of the neuronal cytoskeleton, leading to network dysfunction.