Biology subjects

Kim, A.-R.

Publications and source records attributed to Kim, A.-R..

21 records · Page 2Linked to original sources

bioRxiv2023

Monitoring and maturation of cardiomyocyte differentiated from human induced pluripotent stem cells using a multi-functional tissue engineering platform

BackgroundThe use of human induced pluripotent stem cells (hiPSCs) is attracting attention as a potential personalized therapy for damaged myocardium, as they are accessible and compatible with the human body. The hiPSCs can be effectively differentiated into cardiomyocytes (CMs), which are essential for myocardial regeneration. However, current approaches have been unable to fully replicate the electro-mechanical functions of natural CMs. MethodsAlthough several methods have been used to stimulate hiPSC-CMs for maturation, the ability to integrate multiple stimuli that influence myocardial cell function has been limited. To address this challenge, we have developed a multi-functional tissue engineering system for CMs that is based on a stretchable multielectrode array (SMEA). The SMEA is housed in a mini-incubator and is stretchable, durable and autoclavable. ResultsThe system can independently control co-stimulation parameters of electrical and mechanical stimuli simultaneously. Furthermore, the system can monitor the status of the cells throughout their proliferation and differentiation of hiPSCs, as well as the stimulation of hiPSC-CMs, through electrochemical cell impedance spectroscopy. By applying co-stimulation, we have observed the enhanced maturation of hiPSC-CMs. ConclusionsOur innovative system holds great potential as a tool for improving the culture and engineering of electrogenic cells with enhanced maturity.

bioengineering↗

bioRxiv2021

Protein visualization and manipulation in Drosophila through the use of epitope tags recognized by nanobodies

Expansion of the available repertoire of reagents for visualization and manipulation of proteins will help understand their function. Short epitope tags linked to proteins of interest and recognized by existing binders such as nanobodies facilitate protein studies by obviating the need to isolate new antibodies directed against them. Nanobodies have several advantages over conventional antibodies, as they can be expressed and used as tools for visualization and manipulation of proteins in vivo. Here, we characterize two short (<15 aa) NanoTag epitopes, 127D01 and VHH05) and their corresponding high-affinity nanobodies. We demonstrate their use in Drosophila for in vivo protein detection and re-localization, direct and indirect immunofluorescence, immunoblotting, and immunoprecipitation. We further show that CRISPR-mediated gene targeting provides a straightforward approach to tagging endogenous proteins with the NanoTags. Single copies of the NanoTags, regardless of their location, suffice for detection. This versatile and validated toolbox of tags and nanobodies will serve as a resource for a wide array of applications, including functional studies in Drosophila and beyond.

genetics↗

bioRxiv2018

Somatic uniparental disomy with a rare EFL1 variant causes Shwachman-Diamond syndrome through dysregulating ribosomal protein synthesis

Shwachman-Diamond syndrome (SDS; OMIM: #260400) is caused by variants in SBDS (Shwachman-Bodian-Diamond syndrome gene), which encodes a protein that plays an important role in ribosome assembly. Recent reports suggest that recessive variants in EFL1 are also responsible for SDS. However, the precise genetic mechanism that leads to EFL1-induced SDS remains incompletely understood. Here we present three unrelated Korean SDS patients that carry biallelic pathogenic variants in EFL1 with biased allele frequencies, resulting from a bone marrow-specific somatic uniparental disomy (UPD) in chromosome 15. The recombination events generated cells that were homozygous for the relatively milder variant, allowing for the evasion of catastrophic physiological consequences. Still, the milder EFL1 variant was solely able to impair 80S ribosome assembly and induce SDS features in cell line, zebrafish, and mouse models. The loss of EFL1 resulted in a pronounced inhibition of terminal oligo-pyrimidine element-containing ribosomal protein transcript 80S assembly. Therefore, we propose a more accurate pathogenesis mechanism of EFL1 dysfunction that eventually leads to aberrant translational control and ribosomopathy.

genetics↗