Combined lineage tracing and scRNA-seq reveals unexpected first heart field predominance of human iPSC differentiation.

During mammalian development, the left and right ventricles arise from early populations of cardiac progenitors known as the first and second heart fields, respectively. While these populations have been extensively studied in non-human model systems, their identification and study in vivo human tissues have been limited due to the ethical and technical limitations of accessing gastrulation-stage human embryos. Human-induced pluripotent stem cells (hiPSCs) present an exciting alternative for modeling early human embryogenesis due to their well-established ability to differentiate into all embryonic germ layers. Here, we describe the development of a TBX5/MYL2 lineage tracing reporter system that allows for the identification of FHF- progenitors and their descendants including left ventricular cardiomyocytes. Furthermore, using single-cell RNA sequencing (scRNA-seq) with oligonucleotide-based sample multiplexing, we extensively profiled differentiating hiPSCs across 12 timepoints in two independent iPSC lines. Surprisingly, our reporter system and scRNA-seq analysis revealed a predominance of FHF differentiation using the small molecule Wnt-based 2D differentiation protocol. We compared this data with existing murine and 3D cardiac organoid scRNA-seq data and confirmed the dominance of left ventricular cardiomyocytes (>90%) in our hiPSC-derived progeny. Together, our work provides the scientific community with a powerful new genetic lineage tracing approach as well as a single-cell transcriptomic atlas of hiPSCs undergoing cardiac differentiation.

Parent Perception of School Meals in the San Joaquin Valley during COVID-19: A Photovoice Project.

School-based nutrition programs are crucial to reducing food insecurity. The COVID-19 pandemic adversely impacted students' school meal participation. This study seeks to understand parent views of school meals during COVID-19 to inform efforts to improve participation in school meal programs. Photovoice methodology was used to explore parental perception of school meals in San Joaquin Valley, California, a region of predominately Latino farmworker communities. Parents in seven school districts photographed school meals for a one-week period during the pandemic and then participated in focus group discussions and small group interviews. Focus group discussions and small group interviews were transcribed, and data were analyzed using a team-based, theme-analysis approach. Three primary domains emerged: benefits of school meal distribution, meal quality and appeal, and perceived healthfulness. Parents perceived school meals as beneficial to addressing food insecurity. However, they noted that meals were unappealing, high in added sugar, and unhealthy, which led to discarded meals and decreased participation in the school meal program. The transition to grab-and-go style meals was an effective strategy for providing food to families during pandemic school closures, and school meals remain an important resource for families experiencing food insecurity. However, negative parental perceptions of the appeal and nutritional content of school meals may have decreased school meal participation and increased food waste that could persist beyond the pandemic.

Mitigating childhood food insecurity during COVID-19: a qualitative study of how school districts in California's San Joaquin Valley responded to growing needs.

OBJECTIVES: To explore best practices and challenges in providing school meals during COVID-19 in a low-income, predominantly Latino, urban-rural region. DESIGN: Semi-structured interviews with school district stakeholders and focus groups with parents were conducted to explore school meal provision during COVID-19 from June to August 2020. Data were coded and themes were identified to guide analysis. Community organisations were involved in all aspects of study design, recruitment, data collection and analysis. SETTING: Six school districts in California's San Joaquin Valley. PARTICIPANTS: School district stakeholders (n 11) included food service directors, school superintendents and community partners (e.g. funders, food cooperative). Focus groups (n 6) were comprised of parents (n 29) of children participating in school meal programmes. RESULTS: COVID-19-related challenges for districts included developing safe meal distribution systems, boosting low participation, covering COVID-19-related costs and staying informed of policy changes. Barriers for families included transportation difficulties, safety concerns and a lack of fresh foods. Innovative strategies to address obstacles included pandemic-electronic benefits transfer (EBT), bus-stop delivery, community pick-up locations, batched meals and leveraging partner resources. CONCLUSIONS: A focus on fresher, more appealing meals and greater communication between school officials and parents could boost participation. Districts that leveraged external partnerships were better equipped to provide meals during pandemic conditions. In addition, policies increasing access to fresh foods and capitalising on United States Department of Agriculture waivers could boost school meal participation. Finally, partnering with community organisations and acting upon parent feedback could improve school meal systems, and in combination with pandemic-EBT, address childhood food insecurity.