Biology subjects

Takahashi, M.

Publications and source records attributed to Takahashi, M..

5 recordsLinked to original sources

bioRxiv2018

Straightjacket/α 2δ 3 deregulation is associated with cardiac conduction defects in Myotonic Dystrophy type 1

Cardiac conduction defects decrease life expectancy in myotonic dystrophy type 1 (DM1), a complex toxic CTG repeat disorder involving misbalance between two RNA- binding factors, MBNL1 and CELF1. How this pathogenic DM1 condition translates into cardiac conduction disorders remains poorly understood. Here, we simulated MBNL1 and CELF1 misbalance in the Drosophila heart and identified associated gene deregulations using TU-tagging based transcriptional profiling of cardiac cells. We detected deregulations of several genes controlling cellular calcium levels and among them increased expression of straightjacket/2{delta}3 that encodes a regulatory subunit of a voltage-gated calcium channel. Straightjacket overexpression in the fly heart leads to asynchronous heart beating, a hallmark of affected conduction, whereas cardiac straightjacket knockdown improves these symptoms in DM1 fly models. We also show that ventricular 2{delta}3 expression is low in healthy mice and humans but significantly elevated in ventricular muscles from DM1 patients with conduction defects. Taken together, this suggests that reducing the straightjacket/2{delta}3 transcript levels in ventricular cardiomyocytes could represent a strategy to prevent conduction defects and in particular intraventricular conduction delay associated with DM1 pathology.

genomics↗

bioRxiv2018

Integrative Transcription Start Site Analysis and Physiological Phenotyping Reveal Torpor-Specific Expressions in Mouse Skeletal Muscle

Mice enter an active hypometabolic state, called daily torpor, when they experience a lowered caloric intake under cool ambient temperature (TA). During torpor, the oxygen consumption rate (VO2) drops to less than 30% of the normal rate without harming the body. This safe but severe reduction in metabolism is attractive for various clinical applications; however, the mechanism and molecules involved are unclear. Therefore, here we systematically analyzed the expression landscape of transcription start sites (TSS) in mouse skeletal muscles under various metabolic states to identify torpor-specific transcription patterns. We analyzed the soleus muscles from 38 mice in torpid, non-torpid, and torpor-deprived conditions, and identified 287 torpor-specific promoters. Furthermore, we found that the transcription factor ATF3 was highly expressed during torpor deprivation and that the ATF3-binding motif was enriched in torpor-specific promoters. Our results demonstrate that the mouse torpor has a distinct hereditary genetic background and its peripheral tissues are useful for studying active hypometabolism.

physiology↗

bioRxiv2018

Implantation-Competent Blastocyst-Like Structures from Mouse Pluripotent Stem Cells

Soon after fertilization, the few totipotent cells of mammalian embryos diverge to form a structure called the blastocyst (BC). Although numerous types of cells, including germ cells and extended pluripotency stem cells, have been generated from pluripotent stem cells (PSCs) in-vitro, generating functional BCs only from PSCs has not yet been reported. Here we describe induced self-organizing 3D BC-like structures (iBCs) generated from mouse PSC culture in-vitro. Resembling natural BCs, iBCs have a blastocoel-like cavity and were formed with outer cells that are positive for trophectoderm lineage markers and with inner cells that are positive for pluripotency markers. iBCs transplanted to pseudopregnant mice uteruses implanted, induced decidualization, and exhibited growth and development before resorption, demonstrating that iBCs are implantation-competent. iBC production required the transcription factor Prdm14 and iBC precursor intermediates concomitantly activate the MERVL totipotency related cleavage stage reporter. Thus, our system may contribute to understanding molecular mechanisms underpinning totipotency, embryogenesis, and implantation.\n\nHIGHLIGHTS-Pluripotent cells self-organize blastocyst-like structures in defined conditions.\n-Structures have several extraembryonic and embryonic characteristics of blastocysts.\n-Structures can implant in the uterus and grow before resorption.\n-Totipotency is implicated concomitantly at loci that originate induced blastocysts.

developmental biology↗

bioRxiv2017

Engineering a Functional small RNA Negative Autoregulation Network with Model-guided Design

RNA regulators are powerful components of the synthetic biology toolbox. Here, we expand the repertoire of synthetic gene networks built from these regulators by constructing a transcriptional negative autoregulation (NAR) network out of small RNAs (sRNAs). NAR network motifs are core motifs of natural genetic networks, and are known for reducing network response time and steady state signal noise. Here we use cell-free transcription-translation (TX-TL) reactions and a computational model to design and prototype sRNA NAR constructs. Using parameter sensitivity analysis, we design a simple set of experiments that allow us to accurately predict NAR function in TX-TL. We transfer successful network designs in vivo and show that our sRNA transcriptional network reduces both network response time and noise in steady-state gene expression. This work broadens our ability to construct increasingly sophisticated RNA genetic networks with predictable function.

synthetic biology↗

bioRxiv2017

Can Human Embryonic Stem Cell-Derived Stromal Cells Serve A Starting Material For Myoblasts?

A large number of myocytes is necessary to treat intractable muscular disorders such as Duchenne muscular dystrophy with cell-based therapies. However, starting materials for cellular therapy products such as myoblasts, marrow stromal cells, menstrual blood-derived cells and placenta-derived cells have a limited lifespan and cease to proliferate in vitro. From the viewpoints of manufacturing and quality control, cells with a long lifespan are more suitable as a starting material. In this study, we generated stromal cells for future myoblast therapy from a working cell bank of human embryonic stem cells (ESCs). The ESC-derived CD105+ cells with extensive in vitro proliferation capability exhibited myogenesis and genetic stability in vitro. These results imply that ESC-derived CD105+ cells are another cell source for myoblasts in cell-based therapy for patients with genetic muscular disorders. Since ESCs are immortal, mesenchymal stromal cells generated from ESCs can be manufactured at a large scale in one lot for pharmaceutical purposes.

cell biology↗