Near-perfect precise on-target editing of human hematopoietic stem and progenitor cells.

Precision gene editing in primary hematopoietic stem and progenitor cells (HSPCs) would facilitate both curative treatments for monogenic disorders as well as disease modelling. Precise efficiencies even with the CRISPR/Cas system, however, remain limited. Through an optimization of guide RNA delivery, donor design, and additives, we have now obtained mean precise editing efficiencies >90% on primary cord blood HSCPs with minimal toxicity and without observed off-target editing. The main protocol modifications needed to achieve such high efficiencies were the addition of the DNA-PK inhibitor AZD7648, and the inclusion of spacer-breaking silent mutations in the donor in addition to mutations disrupting the PAM sequence. Critically, editing was even across the progenitor hierarchy, did not substantially distort the hierarchy or affect lineage outputs in colony-forming cell assays or the frequency of high self-renewal potential long-term culture initiating cells. As modelling of many diseases requires heterozygosity, we also demonstrated that the overall editing and zygosity can be tuned by adding in defined mixtures of mutant and wild-type donors. With these optimizations, editing at near-perfect efficiency can now be accomplished directly in human HSPCs. This will open new avenues in both therapeutic strategies and disease modelling.

Expression of cell type incongruent alpha-cardiac actin 1 subunit in medulloblastoma reveals a novel mechanism for cancer cell survival and control of migration.

BACKGROUND: Alterations in actin subunit expression have been reported in multiple cancers, but have not been investigated previously in medulloblastoma. METHODS: Bioinformatic analysis of multiple medulloblastoma tumor databases was performed to profile ACTC1 mRNA levels. Western blot was used to verify protein expression in established medulloblastoma cell lines. Immunofluorescence microscopy was performed to assess ACTC1 localization. Stable cell lines with ACTC1 overexpression were generated and shRNA knockdown of ACTC1 was accomplished. We used PARP1 cleavage by Western blot as a marker of apoptosis and cell survival was determined by FACS viability assay and colony formation. Cell migration with overexpression or knockdown of ACTC1 was determined by the scratch assay. Stress fiber length distribution was assessed by fluorescence microscopy. RESULTS: ACTC1 mRNA expression is highest in SHH and WNT medulloblastoma among all subgroups. ACTC1 protein was confirmed by Western blot in SHH subgroup and Group 3 subgroup cell lines with the lowest expression in Group 3 cells. Microscopy demonstrated ACTC1 co-localization with F-actin. Overexpression of ACTC1 in Group 3 cells abolished the apoptotic response to Aurora kinase B inhibition. Knockdown of ACTC1 in SHH cells and in Myc overexpressing SHH cells induced apoptosis, impaired colony formation, and inhibited migration. Changes in stress fiber length distribution in medulloblastoma cells are induced by alterations in ACTC1 abundance. CONCLUSIONS: Alpha-cardiac actin (ACTC1) is expressed in SHH medulloblastoma. Expression of this protein in medulloblastoma modifies stress fiber composition and functions in promoting resistance to apoptosis induced by mitotic inhibition, enhancing cell survival, and controlling migration.

Building Sangha in the American Healthcare Setting for Persons with Chronic Disease.

BACKGROUND: For persons with chronic disease, participation in meditation interventions can reduce anxiety, depression, and chronic disease symptoms in a dose dependent fashion. Unfortunately, information about how to support long-term participation in such an intervention is lacking. Therefore, a recent discovery of persons with chronic lung disease who have maintained a self-led meditation group for more than four years created an opportunity to analyze experiences, meanings and relationship dynamics of this community-based meditation group. METHODS: A focused ethnography was conducted using the following techniques: participant observation of four group meditation sessions, semi-structured interviews of six group participants, the interviewer's reflective practice and collection of demographic information. Analysis of transcribed audio-recordings followed an iterative approach. RESULTS: Findings highlighted the inclusive nature of the group sessions that supported meditation practice through the processing of ancient wisdom traditions similar to a traditional Sangha. Reflecting the current culture of non-affiliation, the group often moved beyond religious teachings to use the environment, literature and pop culture representations to teach wisdom traditions. Data analysis revealed that the holistic group characteristics of wisdom circling, non-Stopping, organic way-finding and sacred space were supported by identifiable yet inseparable individual and group actions. This holistic pattern is best described through the metaphor of flocking birds. CONCLUSIONS: This self-led group supports long term meditation practice and provides a sense of eudemonic well-being for a diverse group of individuals in an accessible community setting.