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

Constitutive overexpression of periostin delays wound healing in mouse skin

Periostin is a matricellular protein involved in development, maintenance and regulation of tissues and organs via by binding to cell surface integrin receptors. Pathologically, periostin plays an important role in the process of wound healing: as a deficiency of the Postn gene delays wound closure and periostin is consistently upregulated in response to injury and skin diseases. However, the functional role of elevated periostin in the process of wound healing has not been tested. In this study, we generated Postn-transgenic mice under the control of the CAG promoter/enhancer to investigate the effects of constitutive overexpression of full length periostin during its pathophysiological roles. Transgenic mice showed significant overexpression of periostin in skin, lung, and heart, but no morphological changes were observed. However, when these transgenic mice were injured, periostin overexpression delayed the closure of excisional wounds. Expression of IL-1β and TNFα, pro-inflammatory cytokines important for wound healing, was significantly decreased in the transgenic mice, prior to delayed healing. Infiltration of neutrophils and macrophages, the main sources of IL-1β and TNFα, was also downregulated in the transgenic wound sites. From these data, we conclude that enforced expression of periostin delays wound closure due to reduced infiltration of neutrophils and macrophages followed by downregulation of IL-1β and TNFα expression. This suggests that regulated spatiotemporal expression of periostin is important for efficient wound healing and that constitutive periostin overexpression interrupts the normal process of wound closure

Induction of DNA Methylation by Artificial piRNA Production in Male Germ Cells

SummaryGlobal DNA demethylation and subsequent de novo DNA methylation take place in mammalian male embryonic germ cells [1–3]. P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs), which are germline-specific small RNAs, have been postulated to be critically important for de novo DNA methylation of retrotransposon genes, and many proteins, including PIWI family proteins, play pivotal roles in this process [4–6]. In the embryonic mouse testis, two mouse PIWI proteins, mouse PIWI-like (MILI) and mouse PIWI2 (MIWI2), are involved in the biogenesis of piRNAs through the so-called ping-pong amplification cycle [7–10], and long single-stranded RNAs transcribed from the gene regions of piRNA clusters have been proposed to be the initial material [11–16]. However, it remains unclear whether transcription from the piRNA clusters is required for the biogenesis of piRNAs. To answer this question, we developed a novel artificial piRNA production system by simple expression of sense and antisense EGFP mRNAs in embryonic male germ cells in the piRNA biogenesis phase. EGFP expression was silenced by piRNA-dependent DNA methylation, indicating that concomitant expression of sense and antisense RNA transcripts is necessary and sufficient for piRNA production and subsequent piRNA-dependent gene silencing. In addition, we demonstrated that this artificial piRNA induction paradigm could be applied to an endogenous gene essential for spermatogenesis, DNMT3L [3, 17, 18]. This study not only provides novel insights into the molecular mechanisms of piRNA production, but also presents an innovative strategy for inducing epigenetic modification in germ cells

Draft Genome Sequence of a Clinical Isolate of Streptococcus mutans Strain HM

We report the draft genome sequence of Streptococcus mutans strain HM isolated from a 4-year-old girl with infective endocarditis. The genomics information will provide information on the genetic diversity and virulence potential of S. mutans strain HM

Modest Expansion of Vβ2+CD4+ T Cells and No Expansion of Vβ7+CD4+ T Cells in a Subgroup of Kawasaki Disease Patients with Erythematic BCG Inoculation Site Lesions

Background: The similarities between Kawasaki disease (KD) and superantigen (SA) diseases indicate that a microbial SA might cause KD. Viral diseases can trigger an endogenous SA.Methods: We evaluated expression of Vβ2 (responding to staphylococcal TSST-1) and Vβ7 (responding to the endogenous SA induced by type-1 interferon or Epstein-Barr virus infection) on T cells from 70 KD patients along with the following control subjects: 18 non-vasculitic patients (NVs), 7 patients with anaphylactoid purpura (AP), and two with neonatal TSS-like exanthematous disease (NTED), a typical SA disease. We examined the correlation of clinical features of KD with Vβ2+ or Vβ7+CD4+T cell populations.Results: The Vβ2+CD4+T cell rates were comparable between KD patients (9.9±2.9%) and NVs (9.0±1.8%), but were lower in AP patients (6.6±1.8%). However, the Vβ2+CD4+T cell rate was significantly higher in KD patients with erythematic BCG inoculation site lesions (10.8±3.2%) than in those without (8.8±2.1%) and NVs (9.0±1.8%), but much lower than in NTED patients (25.2%, 16.9%). Multivariate linear regression analysis with elevation of Vβ2 expression as a dependent variable revealed significant correlations with BCG. In contrast, Vβ7+CD4+T cell rates were not significantly different between KD patients and other study subjects.Conclusion: While we were unable to find evidence supporting the involvement of the endogenous SA in the pathogenesis of KD in this study, modest expansion of the Vβ2+CD4+T cell population in a subgroup of KD with erythematic BCG inoculation site lesions implies the involvement of a microbial agent(s) different from TSST-1 as well as immunopathological heterogeneity of KD. (249 words

Expanding the Repertoire of Optogenetically Targeted Cells with an Enhanced Gene Expression System

Optogenetics has been enthusiastically pursued in recent neuroscience research, and the causal relationship between neural activity and behavior is becoming ever more accessible. Here, we established knockin-mediated enhanced gene expression by improved tetracycline-controlled gene induction (KENGE-tet) and succeeded in generating transgenic mice expressing a highly light-sensitive channelrhodopsin-2 mutant at levels sufficient to drive the activities of multiple cell types. This method requires two lines of mice: one that controls the pattern of expression and another that determines the protein to be produced. The generation of new lines of either type readily expands the repertoire to choose from. In addition to neurons, we were able to manipulate the activity of nonexcitable glial cells in vivo. This shows that our system is applicable not only to neuroscience but also to any biomedical study that requires understanding of how the activity of a selected population of cells propagates through the intricate organic systems

Hepatocyte Permissiveness to Plasmodium Infection Is Conveyed by a Short and Structurally Conserved Region of the CD81 Large Extracellular Domain

Invasion of hepatocytes by Plasmodium sporozoites is a prerequisite for establishment of a malaria infection, and thus represents an attractive target for anti-malarial interventions. Still, the molecular mechanisms underlying sporozoite invasion are largely unknown. We have previously reported that the tetraspanin CD81, a known receptor for the hepatitis C virus (HCV), is required on hepatocytes for infection by sporozoites of several Plasmodium species. Here we have characterized CD81 molecular determinants required for infection of hepatocytic cells by P. yoelii sporozoites. Using CD9/CD81 chimeras, we have identified in CD81 a 21 amino acid stretch located in a domain structurally conserved in the large extracellular loop of tetraspanins, which is sufficient in an otherwise CD9 background to confer susceptibility to P. yoelii infection. By site-directed mutagenesis, we have demonstrated the key role of a solvent-exposed region around residue D137 within this domain. A mAb that requires this region for optimal binding did not block infection, in contrast to other CD81 mAbs. This study has uncovered a new functionally important region of CD81, independent of HCV E2 envelope protein binding domain, and further suggests that CD81 may not interact directly with a parasite ligand during Plasmodium infection, but instead may regulate the function of a yet unknown partner protein

An integrated expression atlas of miRNAs and their promoters in human and mouse

MicroRNAs (miRNAs) are short non-coding RNAs with key roles in cellular regulation. As part of the fifth edition of the Functional Annotation of Mammalian Genome (FANTOM5) project, we created an integrated expression atlas of miRNAs and their promoters by deep-sequencing 492 short RNA (sRNA) libraries, with matching Cap Analysis Gene Expression (CAGE) data, from 396 human and 47 mouse RNA samples. Promoters were identified for 1,357 human and 804 mouse miRNAs and showed strong sequence conservation between species. We also found that primary and mature miRNA expression levels were correlated, allowing us to use the primary miRNA measurements as a proxy for mature miRNA levels in a total of 1,829 human and 1,029 mouse CAGE libraries. We thus provide a broad atlas of miRNA expression and promoters in primary mammalian cells, establishing a foundation for detailed analysis of miRNA expression patterns and transcriptional control regions

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