Biology subjects

Moriyama, Y.

Publications and source records attributed to Moriyama, Y..

6 recordsLinked to original sources

bioRxiv2025

Influence of Substrate Elastic Modulus on Cell Shape and Displacement During the Motility Cycle

Cardiac fibroblasts play a pivotal role in heart tissue dynamics, responding to mechanical cues from their environment. This study examines how substrate elasticity influences the motility and shape of chicken embryonic cardiac fibroblasts on polydimethylsiloxane (PDMS) substrates of different stiffness (10 kPa and 400 kPa). Using time-lapse phase-contrast microscopy, we identified distinct motility cycles characterized by elongation, contraction, and retraction phases. On soft substrates, cells exhibited slower retraction speeds and longer motility cycles compared to those on hard substrates. Notably, cells on soft substrates left trailing edges upon retraction, leading to pronounced morphological oscillations, whereas cells on hard substrates adopted near-circular shapes with less coordinated motility. Quantitative analyses revealed that the duration of the static phase was significantly shorter on hard substrates, correlating with differences in cell shape parameters, including length, circularity, and area. These findings suggest that substrate elasticity modulates the balance between cell-substrate adhesion and contractile forces, influencing cell polarity and motility. Our work advances the understanding of how mechanical environments shape fibroblast dynamics, offering insights relevant to tissue engineering and fibrosis research. SIGNIFICANCEMechanical cues from the cellular microenvironment are known to regulate cell behavior, yet how substrate stiffness shapes the dynamic motility cycle of fibroblasts remains incompletely understood. Here, we use high-resolution time-lapse imaging to reveal that cardiac fibroblasts on soft (10 kPa) PDMS undergo polarized, oscillatory migration with prolonged static phases, while those on stiff (400 kPa) substrates exhibit rapid retraction and random-like displacement with reduced polarity. These findings highlight how substrate elasticity modulates the interplay between traction forces and adhesion stability, governing directionality and morphology. This work provides mechanobiological insights into fibroblast behavior with implications for designing biomaterials to guide tissue remodeling and fibrosis progression.

biophysics↗

bioRxiv2025

Extracellular stiffness regulates cell fate determination and drives the emergence of evolutionary novelty in teleost heart

The diversification of life is driven by the acquisition of new phenotypic traits, known as evolutionary novelties. While some genetic mechanisms underlying such traits have been identified, the role of physical properties of cellular and extracellular components remains largely unexplored. Here, we show that the evolution and development of the bulbus arteriosus (BA)-a teleost-specific, smooth muscle-rich heart outflow tract-is regulated by the mechanical properties of its extracellular environment. Specifically, we demonstrate that the teleost-specific extracellular matrix gene elastin b confers the uniquely low stiffness of the BA. In contrast to the BA, the homologous organ in non-teleost actinopterygians, the conus arteriosus (CA), and the ventricle are predominantly composed of cardiomyocytes, and exhibit higher extracellular stiffness. Loss of elastin b function by knockdown or knockout leads to ectopic cardiomyocyte formation in the BA, accompanied by increased extracellular stiffness comparable to that of the ventricle. Furthermore, artificial stiffening of the BA extracellular environment is sufficient to induce ectopic cardiomyocyte differentiation. Taken together, these findings demonstrate that extracellular stiffness governs cell fate determination and highlight its role in the emergence of evolutionary novelties in the teleost heart. Significant StatementThe acquisition of new phenotypic traits is a key driver for a diversification of life. While genetic underpinnings of such traits have been well studied, the contribution of physical properties remains elusive. Here, we show that extracellular stiffness plays a key role in the evolution and development of the bulbus arteriosus (BA), a smooth muscle-based cardiac outflow tract unique to teleost hearts. We demonstrate that elastin b, a teleost-specific gene, confers characteristically low stiffness to the BA, which is required for proper cell fate determination. Notably, such low stiffness is absent in non-teleost fishes and in teleosts with impaired elastin b function, and artificial stiffening alters cell fate. Our findings highlight the importance of physical properties in driving evolutionary novelties.

developmental biology↗

bioRxiv2024

hoxb genes determine the timing of cell ingression by regulating cell surface fluctuations during zebrafish gastrulation

During embryonic development, cell behaviors need to be tightly regulated in time and space. Yet, how the temporal and spatial regulations of cell behaviors are interconnected during embryonic development remains elusive. To address this, we turned to zebrafish gastrulation, the process where dynamic cell behaviors generate the three principal germ layers of the early embryo. Here, we show that hoxb cluster genes are expressed in a temporally collinear manner at the blastoderm margin of the embryo to regulate the timing of mesoderm and endoderm (mesendoderm) cell ingression. Under- or over-expression of hoxb genes perturb the timing of mesendoderm cell ingression and, consequently, the positioning of these cells along the forming anterior-posterior body axis. Finally, we found that hoxb genes control the timing of mesendoderm ingression by regulating cell surface fluctuations. Thus, hoxb genes interconnect the temporal and spatial pattern of cell behavior in the early embryo by controlling cell surface fluctuations. HighlightsO_LIhoxb gene expression shows temporal collinearity at the blastoderm margin during zebrafish gastrulation. C_LIO_LITemporal collinear expression of hoxb genes at the blastoderm margin regulates the timing of cell ingression and delineates spatial collinearity after gastrulation. C_LIO_LIhoxb genes regulate cell surface fluctuations and bleb formation at the blastoderm margin during cell ingression C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/579056v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@3a8517org.highwire.dtl.DTLVardef@1f7bda3org.highwire.dtl.DTLVardef@1c325a6org.highwire.dtl.DTLVardef@dce24d_HPS_FORMAT_FIGEXP M_FIG C_FIG hoxb genes are expressed at the blastoderm margin in a temporally collinear manner and determine the timing of mesendoderm ingression by triggering dynamic cell surface fluctuations and cell blebbing. This results in a spatial collinearity of mesendoderm cell positioning along the anterior-posterior extent of the forming body axis with early ingressing cells being positioned more anteriorly than late ingressing cells.

developmental biology↗

bioRxiv2022

Time-resolved transcriptomic profiling of senescence-associated secretory phenotype (SASP) in multiple senescent cell subtypes

Cellular senescence, irreversible cell cycle arrest, is induced by various triggers including telomere shortening, oncogene activation, and DNA damage. Senescent cells exhibit the senescence-associated secretory phenotype (SASP), a pathological feature that contributes to organismal aging. We previously showed that transient plasma membrane damage (PMD) induces a novel subtype of cellular senescence (PMDS) accompanied by SASP, but the overall expression profiles of SASP during PMDS induction was unknown. Here, using mRNA-seq, qPCR, and bioinformatics, we revealed the time-resolved SASP transcriptomic profile in PMDS in comparison with calcium influx-induced senescence, DNA damage response-induced senescence, and replicative senescence. Although the expression of SASP factors was postulated to increase steadily during senescence, we counterintuitively found that the variety of SASP peaks in early PMDS. The pathway comparison analyses and Ingenuity Pathway Analysis suggest that, in early PMDS, wound-healing SASP factors, namely Il-6, Mmp1, and Mmp3, inhibit the GPVI collagen signaling pathway, which in turn further upregulates the same SASP factors, forming a feedback loop. At late senescence, common SASP factors including Il-6 and Ccl2 are upregulated in all senescent cell subtypes. Thus, SASP is diverse at early senescence and becomes relatively uniform at late senescence. Diverse SASP may contribute to senescent cell subtype-specific paracrine/autocrine functions in vivo.

bioinformatics↗

bioRxiv2022

Canonical Wnt Signaling Induces Focal Adhesion and Integrin Beta-1 Endocytosis

During canonical Wnt signaling, the Lrp6 and Frizzled co-receptors bind to the Wnt growth factor and the complex is endocytosed and sequestered together with Glycogen Synthase Kinase 3 (GSK3), Dishevelled (Dvl), and Axin inside the intraluminal vesicles of late endosomes, known as multivesicular bodies (MVBs). Here we present experiments showing that Wnt causes the endocytosis of focal adhesion (FA) proteins and depletion of Integrin {beta} 1 (ITG{beta}1) from the cell surface. FAs and integrins link the cytoskeleton to the extracellular matrix. Wnt-induced endocytosis caused ITG{beta}1 depletion from the plasma membrane and was accompanied by striking changes in the actin cytoskeleton. In situ protease protection assays in cultured cells showed that ITG{beta}1 was sequestered within membrane-bounded organelles that corresponded to Wnt-induced MVBs containing GSK3 and FA-associated proteins. An in vivo model using Xenopus embryos dorsalized by Wnt8 mRNA showed that ITG{beta}1 depletion decreased Wnt signaling. The finding of a crosstalk between two mayor signaling pathways, canonical Wnt and focal adhesions, should be relevant to human cancer and cell biology.

cell biology↗

bioRxiv2021

Plasma membrane damage limits replicative lifespan in yeast and human fibroblasts

Plasma membrane damage (PMD) occurs in all cell types due to environmental perturbation and cell-autonomous activities. However, cellular outcomes of PMD remain largely unknown except for recovery or death. Here, using budding yeast and normal human fibroblasts, we show that cellular senescence, irreversible cell cycle arrest contributing to organismal aging, is the long-term outcome of PMD. To identify the genes essential for PMD response, we developed a simple PMD-damaging assay using a detergent and performed a systematic yeast genome-wide screen. The screen identified 48 genes. The top hits in the screen are the endosomal sorting complexes required for transport (ESCRT) genes, encoding the well-described plasma membrane repair proteins in eukaryotes. Unexpectedly, the replicative lifespan regulator genes are enriched in our 48 hits. This finding suggests a close genetic association between the PMD response and the replicative lifespan regulations. Indeed, we show that PMD limits the replicative lifespan in budding yeast; the ESCRT activator AAA-ATPase VPS4-overexpression extends it. These results suggest that PMD limits replicative lifespan in budding yeast. Moreover, in normal human fibroblasts, we find that PMD induces premature senescence via the Ca2+-p53 axis but not the major senescence pathway, ATM/ATR pathway. Consistent with the results in yeast, transient overexpression of ESCRT-III, CHMP4B, suppressed the PMD-dependent senescence in normal human fibroblasts. Our study proposes that PMD limits cellular lifespan in two different eukaryotic cell types and highlights an underappreciated but ubiquitous senescent cell subtype, namely PMD-dependent senescent cells.

cell biology↗