Genetic studies of human-chimpanzee divergence using stem cell fusions.

Complete genome sequencing has identified millions of DNA changes that differ between humans and chimpanzees. Although a subset of these changes likely underlies important phenotypic differences between humans and chimpanzees, it is currently difficult to distinguish causal from incidental changes and to map specific phenotypes to particular genome locations. To facilitate further genetic study of human-chimpanzee divergence, we have generated human and chimpanzee autotetraploids and allotetraploids by fusing induced pluripotent stem cells (iPSCs) of each species. The resulting tetraploid iPSCs can be stably maintained and retain the ability to differentiate along ectoderm, mesoderm, and endoderm lineages. RNA sequencing identifies thousands of genes whose expression differs between humans and chimpanzees when assessed in single-species diploid or autotetraploid iPSCs. Analysis of gene expression patterns in interspecific allotetraploid iPSCs shows that human-chimpanzee expression differences arise from substantial contributions of both cis-acting changes linked to the genes themselves and trans-acting changes elsewhere in the genome. To enable further genetic mapping of species differences, we tested chemical treatments for stimulating genome-wide mitotic recombination between human and chimpanzee chromosomes, and CRISPR methods for inducing species-specific changes on particular chromosomes in allotetraploid cells. We successfully generated derivative cells with nested deletions or interspecific recombination on the X chromosome. These studies confirm an important role for the X chromosome in trans regulation of expression differences between species and illustrate the potential of this system for more detailed cis and trans mapping of the molecular basis of human and chimpanzee evolution.

Improving Cancer Patients' Insurance Choices (I Can PIC): A Randomized Trial of a Personalized Health Insurance Decision Aid.

BACKGROUND: Many cancer survivors struggle to choose a health insurance plan that meets their needs because of high costs, limited health insurance literacy, and lack of decision support. We developed a web-based decision aid, Improving Cancer Patients' Insurance Choices (I Can PIC), and evaluated it in a randomized trial. MATERIALS AND METHODS: Eligible individuals (18-64 years, diagnosed with cancer for ≤5 years, English-speaking, not Medicaid or Medicare eligible) were randomized to I Can PIC or an attention control health insurance worksheet. Primary outcomes included health insurance knowledge, decisional conflict, and decision self-efficacy after completing I Can PIC or the control. Secondary outcomes included knowledge, decisional conflict, decision self-efficacy, health insurance literacy, financial toxicity, and delayed care at a 3-6-month follow-up. RESULTS: A total of 263 of 335 eligible participants (79%) consented and were randomized; 206 (73%) completed the initial survey (106 in I Can PIC; 100 in the control), and 180 (87%) completed a 3-6 month follow-up. After viewing I Can PIC or the control, health insurance knowledge and a health insurance literacy item assessing confidence understanding health insurance were higher in the I Can PIC group. At follow-up, the I Can PIC group retained higher knowledge than the control; confidence understanding health insurance was not reassessed. There were no significant differences between groups in other outcomes. Results did not change when controlling for health literacy and employment. Both groups reported having limited health insurance options. CONCLUSION: I Can PIC can improve cancer survivors' health insurance knowledge and confidence using health insurance. System-level interventions are needed to lower financial toxicity and help patients manage care costs. IMPLICATIONS FOR PRACTICE: Inadequate health insurance compromises cancer treatment and impacts overall and cancer-specific mortality. Uninsured or underinsured survivors report fewer recommended cancer screenings and may delay or avoid needed follow-up cancer care because of costs. Even those with adequate insurance report difficulty managing care costs. Health insurance decision support and resources to help manage care costs are thus paramount to cancer survivors' health and care management. We developed a web-based decision aid, Improving Cancer Patients' Insurance Choices (I Can PIC), and evaluated it in a randomized trial. I Can PIC provides health insurance information, supports patients through managing care costs, offers a list of financial and emotional support resources, and provides a personalized cost estimate of annual health care expenses across plan types.

Decisional conflict associated with clinicians discouraging particular contraceptive methods.

RATIONALE, AIMS, AND OBJECTIVES: Approximately 45% of pregnancies in the United States are unintended. The use of contraception reduces the risk of unintended pregnancy. The initiation of several contraceptive methods requires seeing a clinician. This study explored how clinicians' expressed preferences against particular contraceptive methods impacted participants' confidence in their method choice and perception of shared contraceptive decision making. METHODS: Eligible individuals were 18 to 45 years of age, assigned female sex at birth, English speaking, and either using or had previously used contraception. Participants completed an anonymous survey via web link on Amazon Mechanical Turk. Primary self-reported outcomes were (a) proportion of participants being discouraged from a particular contraceptive method, (b) decisional conflict, and (c) extent of shared decision making. Secondary self-reported outcomes were (a) importance of contraceptive attributes and (b) self-reported quality of care. RESULTS: Six hundred sixty-nine participants completed the survey. Most were white (74.0%), non-Hispanic (84.5%), married or cohabitating (69.4%), and nulliparous (47.2%). A total of 33.8% reported that a clinician had discouraged them from using a particular contraceptive method, most commonly because of side effects, usability, and/or method effectiveness. Effectiveness, affordability, and side effects were the self-reported most important contraceptive features. Those who were discouraged from using a method (versus those who were not) were more likely to report decisional conflict (41.2% vs 30.0%, P = .004), yet reported a higher extent of shared decision making (median: 76 vs 71; P = .03). Adjusting for age and nulliparity did not impact results, except nulliparity made the relationship between being discouraged from using a method and shared decision making no longer significant (P = .06). CONCLUSIONS: Decisional conflict might arise when clinicians discourage individuals using particular contraceptive methods. Clinicians' reasons for discouraging methods might not always align with patients' preferences. More research is needed to examine how to reduce decisional conflict and support contraceptive method selection.

MLL1 is essential for retinal neurogenesis and horizontal inner neuron integrity.

Development of retinal structure and function is controlled by cell type-specific transcription factors and widely expressed co-regulators. The latter includes the mixed-lineage leukemia (MLL) family of histone methyltransferases that catalyze histone H3 lysine 4 di- and tri-methylation associated with gene activation. One such member, MLL1, is widely expressed in the central nervous system including the retina. However, its role in retinal development is unknown. To address this question, we knocked out Mll1 in mouse retinal progenitors, and discovered that MLL1 plays multiple roles in retinal development by regulating progenitor cell proliferation, cell type composition and neuron-glia balance, maintenance of horizontal neurons, and formation of functional synapses between neuronal layers required for visual signal transmission and processing. Altogether, our results suggest that MLL1 is indispensable for retinal neurogenesis and function development, providing a new paradigm for cell type-specific roles of known histone modifying enzymes during CNS tissue development.

Differential timing of granule cell production during cerebellum development underlies generation of the foliation pattern.

BACKGROUND: The mouse cerebellum (Cb) has a remarkably complex foliated three-dimensional (3D) structure, but a stereotypical cytoarchitecture and local circuitry. Little is known of the cellular behaviors and genes that function during development to determine the foliation pattern. In the anteroposterior axis the mammalian cerebellum is divided by lobules with distinct sizes, and the foliation pattern differs along the mediolateral axis defining a medial vermis and two lateral hemispheres. In the vermis, lobules are further grouped into four anteroposterior zones (anterior, central, posterior and nodular zones) based on genetic criteria, and each has distinct lobules. Since each cerebellar afferent group projects to particular lobules and zones, it is critical to understand how the 3D structure of the Cb is acquired. During cerebellar development, the production of granule cells (gcs), the most numerous cell type in the brain, is required for foliation. We hypothesized that the timing of gc accumulation is different in the four vermal zones during development and contributes to the distinct lobule morphologies. METHODS AND RESULTS: In order to test this idea, we used genetic inducible fate mapping to quantify accumulation of gcs in each lobule during the first two postnatal weeks in mice. The timing of gc production was found to be particular to each lobule, and delayed in the central zone lobules relative to the other zones. Quantification of gc proliferation and differentiation at three time-points in lobules representing different zones, revealed the delay involves a later onset of maximum differentiation and prolonged proliferation of gc progenitors in the central zone. Similar experiments in Engrailed mutants (En1 (-/+) ;En2 (-/-) ), which have a smaller Cb and altered foliation pattern preferentially outside the central zone, showed that gc production, proliferation and differentiation are altered such that the differences between zones are attenuated compared to wild-type mice. CONCLUSIONS: Our results reveal that gc production is differentially regulated in each zone of the cerebellar vermis, and our mutant analysis indicates that the dynamics of gc production plays a role in determining the 3D structure of the Cb.