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Biology subjects

Cho, S.-h.

Publications and source records attributed to Cho, S.-h..

2 recordsLinked to original sources

Development of human iPSC-derived cardiomyocytes-based heart-on-a-chip with customized multi-electrode array for drug-induced cardiotoxicity evaluations

The heart is an essential organ at the beginning and end of life. Cardiotoxicity directly related to life is emphasized as an absolute safety factor in drug development, so it is indispensable to evaluate it accurately. That is why establishing a novel platform that can precisely recapitulate human cardiophysiological properties is necessary. Here, we report a human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes-based heart-on-a-chip integrated with a customized multi-electrode array (cMEA), capable of actualizing a cardiac muscle fascicle and surrounding capillaries tridimensionally. The differences in experimental reproducibility, scale of field potential wave, and gene expression patterns according to the two-dimensional cell-level and three-dimensional tissue-level culture are confirmed. Excellent accuracy of drug efficacy/toxicity of the chip is also verified relative to other conventional cell culture platforms by looking at heart rate changes depending on drug type and concentration/time. Additionally, we checked that kinetic/electrophysiological/molecular biological analysis can be performed with our chip by applying motion tracking, cMEA, and RNA sequencing. Thus, our platform is expected to be used as a tool for more exact cardiotoxicity tests with high reproducibility and multi-angle analysis in line with new pharmacological safety assessments such as comprehensive cardiac arrhythmias assessment (CiPA).

bioengineering↗

Proximal recolonization by self-renewing microglia re-establishes microglial homeostasis in the adult mouse brain

Microglia are resident immune cells that play critical roles in maintaining normal physiology of the central nervous system. Remarkably, microglia have intrinsic capacity to replenish after being acutely ablated. However, the underlying mechanisms that drive such microglial restoration remain elusive. Here, we removed microglia via CSF1R inhibitor PLX5622 and characterized repopulation both spatially and temporally. We also investigated the cellular origin of repopulated microglia and report that microglia are replenished via self-renewal, with little contribution from non-microglial lineage progenitors, including nestin+ progenitors and the circulating myeloid population. Interestingly, spatial analyses with multi-color labeling reveal that newborn microglia recolonize the parenchyma by forming distinctive clusters that maintain stable territorial boundaries over time, indicating proximal expansion nature of adult microgliogenesis and stability of microglia tiling. Temporal transcriptome profiling from newborn microglia at different repopulation stages revealed that the adult newborn microglia gradually regain steady-state maturity from an immature state that is reminiscent of neonatal stage and follow a series of maturation programs that include NF-{kappa}B activation, interferon immune activation and apoptosis, etc. Importantly, we show that the restoration of microglial homeostatic density requires NF-{kappa}B signaling as well as apoptotic egress of excessive cells. In summary, our study reports key events that take place from microgliogenesis to homeostasis re-establishment.

neuroscience↗