Heterogeneity in cell populations poses a major obstacle to understanding complex biological processes. Here we present a microfluidic platform containing thousands of nanoliter-scale chambers suitable for live-cell imaging studies of clonal cultures of nonadherent cells with precise control of the conditions, capabilities for in situ immunostaining and recovery of viable cells. We show that this platform mimics conventional cultures in reproducing the responses of various types of primitive mouse hematopoietic cells with retention of their functional properties, as demonstrated by subsequent in vitro and in vivo (transplantation) assays of recovered cells. The automated medium exchange of this system made it possible to define when Steel factor stimulation is first required by adult hematopoietic stem cells in vitro as the point of exit from quiescence. This technology will offer many new avenues to interrogate otherwise inaccessible mechanisms governing mammalian cell growth and fate decisions.

Chromatin modulators are emerging as attractive drug targets, given their widespread implication in human cancers and susceptibility to pharmacological inhibition. Here we establish the histone methyltransferase G9a/ EHMT2 as a selective regulator of fast proliferating myeloid progenitors with no discernible function in hematopoietic stem cells (HSCs). In mouse models of acute myeloid leukemia (AML), loss of G9a significantly delays disease progression and reduces leukemia stem cell (LSC) frequency. We connect this function of G9a to its methyltransferase activity and its interaction with the leukemogenic transcription factor HoxA9 and provide evidence that primary human AML cells are sensitive to G9A inhibition. Our results highlight a clinical potential of G9A inhibition as a means to counteract the proliferation and self-renewal of AML cells by attenuating HoxA9-dependent transcription.

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The coronavirus (COVID-19) pandemic temporarily suspended medical student involvement in clinical rotations, resulting in the need to develop virtual clinical experiences. The cancellation of clinical ophthalmology electives and away rotations reduces opportunities for exposure to the field, to network with faculty, conduct research, and prepare for residency applications. We review the literature and discuss the impact and consequences of COVID-19 on undergraduate medical education (UME) with an emphasis on ophthalmic UME. We also discuss innovative learning modalities used from medical schools around the world during the COVID-19 pandemic such as virtual didactics, online cases, and telehealth. Finally, we describe a novel, virtual neuro-ophthalmology elective created to educate medical students on neuro-ophthalmology foundational principles, provide research and presentation opportunities, and build relationships with faculty members. These innovative approaches represent a step forward in further improving medical education in ophthalmology during COVID-19 and beyond.