Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality

Daiji Kiyozumi, Yukimasa Taniguchi, Itsuko Nakano, Junko Toga, Emiko Yagi, Hidetoshi Hasuwa, Masahito Ikawa, and Kiyotoshi Sekiguchi, "Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality", Life Science Alliance, Vol.1, No.5, e201800064, Life Science Alliance, 201

Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality

Daiji Kiyozumi, Yukimasa Taniguchi, Itsuko Nakano, Junko Toga, Emiko Yagi, Hidetoshi Hasuwa, Masahito Ikawa, and Kiyotoshi Sekiguchi, "Laminin γ1 C-terminal Glu to Gln mutation induces early postimplantation lethality", Life Science Alliance, Vol.1, No.5, e201800064, Life Science Alliance, 201

Selective Laminin-Directed Differentiation of Human Induced Pluripotent Stem Cells into Distinct Ocular Lineages

Summary: The extracellular matrix plays a key role in stem cell maintenance, expansion, and differentiation. Laminin, a basement membrane protein, is a widely used substrate for cell culture including the growth of human induced pluripotent stem cells (hiPSCs). Here, we show that different isoforms of laminin lead to the selective differentiation of hiPSCs into different eye-like tissues. Specifically, the 211 isoform of the E8 fragment of laminin (LN211E8) promotes differentiation into neural crest cells via Wnt activation, whereas LN332E8 promotes differentiation into corneal epithelial cells. The immunohistochemical distributions of these laminin isoforms in the developing mouse eye mirrors the hiPSC type that was induced in vitro. Moreover, LN511E8 enables generation of dense hiPSC colonies due to actomyosin contraction, which in turn led to cell density-dependent YAP inactivation and subsequent retinal differentiation in colony centers. Thus, distinct laminin isoforms determine the fate of expanded hiPSCs into eye-like tissues. : Shibata et al. report that laminin isoforms differentially regulate the ocular cell differentiation from hiPSCs. The binding affinity of laminin and integrins determines the nature of expanded hiPSC colonies in terms of cell motility, cell-cell interactions, and cell density, with the involvement of Wnt and YAP signals. Keywords: human induced pluripotent stem cells, hiPSCs, laminin isoforms, YAP, Wnt, ocular cell differentiation, self-formed ectodermal autonomous multi-zone, SEA

Laminin-guided highly efficient endothelial commitment from human pluripotent stem cells.

細胞外マトリックスを用いてヒト多能性幹細胞から高効率に血管内皮細胞の誘導に成功. 京都大学プレスリリース. 2016-11-09.Obtaining highly purified differentiated cells via directed differentiation from human pluripotent stem cells (hPSCs) is an essential step for their clinical application. Among the various conditions that should be optimized, the precise role and contribution of the extracellular matrix (ECM) during differentiation are relatively unclear. Here, using a short fragment of laminin 411 (LM411-E8), an ECM predominantly expressed in the vascular endothelial basement membrane, we demonstrate that the directed switching of defined ECMs robustly yields highly-purified (>95%) endothelial progenitor cells (PSC-EPCs) without cell sorting from hPSCs in an integrin-laminin axis-dependent manner. Single-cell RNA-seq analysis revealed that LM411-E8 resolved intercellular transcriptional heterogeneity and escorted the progenitor cells to the appropriate differentiation pathway. The PSC-EPCs gave rise to functional endothelial cells both in vivo and in vitro. We therefore propose that sequential switching of defined matrices is an important concept for guiding cells towards desired fate

Rhinoceros beetle horn development reveals deep parallels with dung beetles

Beetle horns are attractive models for studying the evolution of novel traits, as they display diverse shapes, sizes, and numbers among closely related species within the family Scarabaeidae. Horns radiated prolifically and independently in two distant subfamilies of scarabs, the dung beetles (Scarabaeinae), and the rhinoceros beetles (Dynastinae). However, current knowledge of the mechanisms underlying horn diversification remains limited to a single genus of dung beetles, Onthophagus. Here we unveil 11 horn formation genes in a rhinoceros beetle, Trypoxylus dichotomus. These 11 genes are mostly categorized as larval head- and appendage-patterning genes that also are involved in Onthophagus horn formation, suggesting the same suite of genes was recruited in each lineage during horn evolution. Although our RNAi analyses reveal interesting differences in the functions of a few of these genes, the overwhelming conclusion is that both head and thoracic horns develop similarly in Trypoxylus and Onthophagus, originating in the same developmental regions and deploying similar portions of appendage patterning networks during their growth. Our findings highlight deep parallels in the development of rhinoceros and dung beetle horns, suggesting either that both horn types arose in the common ancestor of all scarabs, a surprising reconstruction of horn evolution that would mean the majority of scarab species (~35,000) actively repress horn growth, or that parallel origins of these extravagant structures resulted from repeated co-option of the same underlying developmental processes

A Mutation in Rab38 Small GTPase Causes Abnormal Lung Surfactant Homeostasis and Aberrant Alveolar Structure in Mice

The chocolate mutation, which is associated with oculocutaneous albinism in mice, has been attributed to a G146T transversion in the conserved GTP/GDP-interacting domain of Rab38, a small GTPase that regulates intracellular vesicular trafficking. Rab38 displays a unique tissue-specific expression pattern with highest levels present in the lung. The purpose of this study was to characterize the effects of Rab38-G146T on lung phenotype and to investigate the molecular basis of the mutant gene product (Rab38cht protein). Chocolate lungs exhibited a uniform enlargement of the distal airspaces with mild alveolar destruction as well as a slight increase in lung compliance. Alveolar type II cells were engorged with lamellar bodies of increased size and number. Hydrophobic surfactant constituents (ie, phosphatidylcholine and surfactant protein B) were increased in lung tissues but decreased in alveolar spaces, consistent with a malfunction in lamellar body secretion and the subsequent cellular accumulation of these organelles. In contrast to wild-type Rab38, native Rab38cht proteins were found to be hydrophilic and not bound to intracellular membranes. Unexpectedly, recombinant Rab38cht proteins retained GTP-binding activity but failed to undergo prenyl modification that is required for membrane-binding activity. These results suggest that the genetic abnormality of Rab38 affects multiple lysosome-related organelles, resulting in lung disease in addition to oculocutaneous albinism