SARS-CoV-2 infection of airway organoids reveals conserved use of Tetraspanin-8 by Ancestral, Delta, and Omicron variants

NF-κB inhibitor alpha controls SARS-CoV-2 infection in ACE2-overexpressing human airway organoids

As SARS-CoV-2 continues to spread worldwide, tractable primary airway cell models that recapitulate the cell-intrinsic response to arising viral variants are needed. Here we describe an adult stem cell-derived human airway organoid model overexpressing the ACE2 receptor (ACE2-OE) that supports robust viral replication while maintaining 3D architecture and cellular diversity of the airway epithelium. ACE2-OE organoids were infected with SARS-CoV-2 variants and subjected to single-cell RNA-sequencing. Interferon-lambda was upregulated in cells with low-level infection while the NF-kB inhibitor alpha gene (encoding IkBa) was consistently upregulated in infected cells, and its expression positively correlated with infection levels. Confocal microscopy showed more IkBa expression in infected than bystander cells, but found concurrent nuclear translocation of NF-kB that IkBa usually prevents. Overexpressing a nondegradable IkBa mutant reduced NF-kB translocation and increased viral infection. These data demonstrate the functionality of ACE2-OE organoids in SARS-CoV-2 research and underscore that the strength of the NF-kB feedback loop in infected cells controls viral replication.

Molecular Regulation and Oncogenic Functions of TSPAN8

Tetraspanins, a superfamily of small integral membrane proteins, are characterized by four transmembrane domains and conserved protein motifs that are configured into a unique molecular topology and structure in the plasma membrane. They act as key organizers of the plasma membrane, orchestrating the formation of specialized microdomains called "tetraspanin-enriched microdomains (TEMs)" or "tetraspanin nanodomains" that are essential for mediating diverse biological processes. TSPAN8 is one of the earliest identified tetraspanin members. It is known to interact with a wide range of molecular partners in different cellular contexts and regulate diverse molecular and cellular events at the plasma membrane, including cell adhesion, migration, invasion, signal transduction, and exosome biogenesis. The functions of cell-surface TSPAN8 are governed by ER targeting, modifications at the Golgi apparatus and dynamic trafficking. Intriguingly, limited evidence shows that TSPAN8 can translocate to the nucleus to act as a transcriptional regulator. The transcription of TSPAN8 is tightly regulated and restricted to defined cell lineages, where it can serve as a molecular marker of stem/progenitor cells in certain normal tissues as well as tumors. Importantly, the oncogenic roles of TSPAN8 in tumor development and cancer metastasis have gained prominence in recent decades. Here, we comprehensively review the current knowledge on the molecular characteristics and regulatory mechanisms defining TSPAN8 functions, and discuss the potential and significance of TSPAN8 as a biomarker and therapeutic target across various epithelial cancers.

Single cell proteomics characterization of bone marrow hematopoiesis with distinct Ras pathway lesions

Normal hematopoiesis requires constant prolific production of different blood cell lineages by multipotent hematopoietic stem cells (HSC). Stem- and progenitor- cells need to balance dormancy with proliferation. How genetic alterations impact frequency, lineage potential, and metabolism of HSC is largely unknown. Here, we compared induced expression of KRAS G12D or RasGRP1 to normal hematopoiesis. At low-resolution, both Ras pathway lesions result in skewing towards myeloid lineages. Single-cell resolution CyTOF proteomics unmasked an expansion of HSC- and progenitor- compartments for RasGRP1, contrasted by a depletion for KRAS G12D . SCENITH™ quantitates protein synthesis with single-cell precision and corroborated that immature cells display low metabolic SCENITH™ rates. Both RasGRP1 and KRAS G12D elevated mean SCENITH™ signals in immature cells. However, RasGRP1-overexpressing stem cells retain a metabolically quiescent cell-fraction, whereas this fraction diminishes for KRAS G12D . Our temporal single cell proteomics and metabolomics datasets provide a resource of mechanistic insights into altered hematopoiesis at single cell resolution.

Parents' Views on Autopsy, Organ Donation, and Research Donation After Neonatal Death

Importance

Parents who experience neonatal loss have the option to participate in autopsy, organ donation, and research donation. However, clinicians are uncomfortable discussing autopsy and may not be aware of research and organ donation opportunities.

Objective

To capture the perspectives of parents who had experienced neonatal loss about autopsy, organ donation, and research donation.

Design, Setting, and Participants

This qualitative study used virtual focus groups with parents who attended a local bereavement support group in the US. Participants were recruited from Helping After Neonatal Death, a support group with a local chapter. Participants self-selected from an email request if they met the following criteria: aged 18 years or older, English speaking, at least 6 months elapsed since neonatal death, and access to a video conference device with internet. Focus groups took place between April and September 2021. The recorded sessions were analyzed using a grounded theory-informed approach by the research team that included parents with experience of neonatal loss. Data were analyzed from December 2021 through December 2022.

Results

A total of 14 mothers engaged in the focus group; 9 (75%) were aged 30 to 39 years, and 8 (66%) were White. The mothers were overall well educated. The first main theme grew from the lived experience of neonatal loss, specifically the importance of offering all parents the option to donate, rather than prejudging who would or would not be interested. Parents of neonates who die have few opportunities to parent that child and make loving decisions for them. Participants emphasized that the conversation about autopsy, organ donation, and research donation, albeit difficult, can offer a meaningful parenting experience. A second main theme that emerged related to how organ or tissue donation could provide additional meaning to a child's life. These choices contributed to building a legacy to honor their child's memory, which also helped with grief and coping with their loss. A third theme included recommendations to clinicians and health systems for improving communication, including written information for parents and communication training for health care professionals.

Conclusions and Relevance

In this qualitative study, parents who experienced neonatal loss endorsed the importance of offering parents the choice of autopsy, organ donation, or research donation with skillful and empathetic communication. They provided practical recommendations to improve communication and empower families.