Histological and Transcriptomic Analysis of Adult Japanese Medaka Sampled Onboard the International Space Station

To understand how humans adapt to the space environment, many experiments can be conducted on astronauts as they work aboard the Space Shuttle or the International Space Station (ISS). We also need animal experiments that can apply to human models and help prevent or solve the health issues we face in space travel. The Japanese medaka (Oryzias latipes) is a suitable model fish for studying space adaptation as evidenced by adults of the species having mated successfully in space during 15 days of flight during the second International Microgravity Laboratory mission in 1994. The eggs laid by the fish developed normally and hatched as juveniles in space. In 2012, another space experiment (“Medaka Osteoclast”) was conducted. Six-week-old male and female Japanese medaka (Cab strain osteoblast transgenic fish) were maintained in the Aquatic Habitat system for two months in the ISS. Fish of the same strain and age were used as the ground controls. Six fish were fixed with paraformaldehyde or kept in RNA stabilization reagent (n = 4) and dissected for tissue sampling after being returned to the ground, so that several principal investigators working on the project could share samples. Histology indicated no significant changes except in the ovary. However, the RNA-seq analysis of 5345 genes from six tissues revealed highly tissue-specific space responsiveness after a two-month stay in the ISS. Similar responsiveness was observed among the brain and eye, ovary and testis, and the liver and intestine. Among these six tissues, the intestine showed the highest space response with 10 genes categorized as oxidation–reduction processes (gene ontogeny term GO:0055114), and the expression levels of choriogenin precursor genes were suppressed in the ovary. Eleven genes including klf9, klf13, odc1, hsp70 and hif3a were upregulated in more than four of the tissues examined, thus suggesting common immunoregulatory and stress responses during space adaptation.     

Sense-overlapping lncRNA as a decoy of translational repressor protein for dimorphic gene expression

Long noncoding RNAs (lncRNAs) are vastly transcribed and extensively studied but lncRNAs overlapping with the sense orientation of mRNA have been poorly studied. We analyzed the lncRNA DAPALR overlapping with the 5´ UTR of the Doublesex1 (Dsx1), the male determining gene in Daphnia magna. By affinity purification, we identified an RNA binding protein, Shep as a DAPALR binding protein. Shep also binds to Dsx1 5´ UTR by recognizing the overlapping sequence and suppresses translation of the mRNA. In vitro and in vivo analyses indicated that DAPALR increased Dsx1 translation efficiency by sequestration of Shep. This regulation was impaired when the Shep binding site in DAPALR was deleted. These results suggest that Shep suppresses the unintentional translation of Dsx1 by setting a threshold; and when the sense lncRNA DAPALR is expressed, DAPALR cancels the suppression caused by Shep. This mechanism may be important to show dimorphic gene expressions such as sex determination and it may account for the binary expression in various developmental processes.     

Hypoxic preconditioning reinforces cellular functions of autologous peripheral blood-derived cells in rabbit hindlimb ischemia model

Peripheral blood mononuclear cell (PBMNC) is one of powerful tools for therapeutic angiogenesis in hindlimb ischemia. However, traditional approaches with transplanted PBMNCs show poor therapeutic effects in severe ischemia patients. In this study, we used autograft models to determine whether hypoxic pretreatment effectively enhances the cellular functions of PBMNCs and improves hindlimb ischemia. Rabbit PBMNCs were cultured in the hypoxic condition. After pretreatment, cell adhesion, stress resistance, and expression of angiogenic factor were evaluated in vitro. To examine in vivo effects, we autografted preconditioned PBMNCs into a rabbit hindlimb ischemia model on postoperative day (POD) 7. Preconditioned PBMNCs displayed significantly enhanced functional capacities in resistance to oxidative stress, cell viability, and production of vascular endothelial growth factor. In addition, autologous transplantation of preconditioned PBMNCs significantly induced new vessels and improved limb blood flow. Importantly, preconditioned PBMNCs can accelerate vessel formation despite transplantation on POD 7, whereas untreated PBMNCs showed poor vascularization. Our study demonstrated that hypoxic preconditioning of PBMNCs is a feasible approach for increasing the retention of transplanted cells and enhancing therapeutic angiogenesis in ischemic tissue.     

CD98hc regulates the development of experimental colitis by controlling effector and regulatory CD4 T cells

CD4⁺ T cell activation is controlled by signaling through the T cell receptor in addition to various co-receptors, and is also affected by their interactions with effector and regulatory T cells in the microenvironment. Inflammatory bowel diseases (IBD) are caused by the persistent activation and expansion of auto-aggressive CD4⁺ T cells that attack intestinal epithelial cells. However, the molecular basis for the persistent activation of CD4⁺ T cells in IBD remains unclear. In this study, we investigated how the CD98 heavy chain (CD98hc, Slc3a2) affected the development of colitis in an experimental animal model. Transferring CD98hc-deficient CD4⁺CD25⁻ T cells into Rag2^−/− mice did not cause colitis accompanied by increasing Foxp3⁺ inducible regulatory T cells. By comparison, CD98hc-deficient naturally occurring regulatory T cells (nTregs) had a decreased capability to suppress colitis induced by CD4⁺CD25⁻ T cells, although CD98hc-deficient mice did not have a defect in the development of nTregs. Blocking CD98hc with an anti-CD98 blocking antibody prevented the development of colitis. Our results indicate that CD98hc regulates the expansion of autoimmune CD4⁺ T cells in addition to controlling nTregs functions, which suggests the CD98hc as an important target molecule for establishing strategies for treating colitis.     

Mono- and triglycosylsterols from the leafy stem of rice

Two sterylglycosides have been isolated from rice plants and identified as β-d-glucopyranosyl (1 → 3)-sitosterol and β-d-glucopyranosyl(1     

Association of the Rv0679c protein with lipids and carbohydrates in <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis>/<Emphasis Type="Italic">Mycobacterium bovis</Emphasis> BCG

The Rv0679c gene in Mycobacterium tuberculosis H37Rv encodes a protein with a predicted molecular mass of 16,586 Da consisting of 165 amino acids which contains a putative N-terminal signal sequence and a consensus lipoprotein-processing motif. Globomycin treatment, Triton X-114 separation and mass spectrometry analyses clarified a property of the Rv0679c protein as a lipoprotein. In addition, trifluoromethanesulphonic acid treatment of the lysate revealed an association of the recombinant Rv0679c protein with carbohydrates. The Rv0679c protein homolog of Mycobacterium bovis BCG was also expressed as the protein associated with lipids and carbohydrates. In Western blot analysis, each of the protein homolog and Lipoarabinomannan (LAM) was detected as a similar pattern by anti-Rv0679c and anti-LAM antibodies, respectively. Interestingly, the Rv0679c protein was detected in commercially available LAM purified from M. tuberculosis. Inhibition assay of LAM synthesis in M. bovis BCG by ethambutol showed an altered migration pattern of the Rv0679c protein to low molecular mass similar to that of LAM. The results suggest that the Rv0679c protein exists as a tight complex with LAM in M. tuberculosis/M. bovis BCG.     

Brünnich's guillemots (Uria lomvia) maintain high temperature in the body core during dives

A major challenge for diving birds, reptiles, and mammals is regulating body temperature while conserving oxygen through a reduction in metabolic processes. To gain insight into how these needs are met, we measured dive depth and body temperatures at the core or periphery between the skin and abdominal muscles simultaneously in freely diving Brünnich's guillemots (Uria lomvia), an arctic seabird, using an implantable data logger (16-mm diameter, 50-mm length, 14-g mass, Little Leonardo Ltd., Tokyo). Guillemots exhibited increased body core temperatures, but decreased peripheral temperatures, during diving. Heat conservation within the body core appeared to result from the combined effect of peripheral vasoconstriction and a high wing beat frequency that generates heat. Conversely, the observed tissue hypothermia in the periphery should reduce metabolic processes as well as heat loss to the water. These physiological effects are likely one of the key physiological adaptations that makes guillemots to perform as an efficient predator in arctic waters.     

Isolation and characterization of the gene encoding a chitin synthase with a myosin motor-like domain from the edible basidiomycetous mushroom, <Emphasis Type="Italic">Lentinula edodes</Emphasis>, and its expression in the course of fruit-body formation

We isolated and characterized the genomic and complementary DNAs encoding a chitin synthase from an edible basidiomycetous mushroom, Lentinula edodes. The gene (which we designated Lechs1) contains a large open reading frame encoding a polypeptide of 1937 amino acid residues. The open reading frame is interrupted by 14 small introns (49–116 bp). The gene product (LeChs1) consists of a myosin motor-like domain in its N-terminal half and a chitin synthase domain in its C-terminal half, analogous to the class V and VI chitin synthases of other filamentous fungi. Phylogenetic analysis demonstrated that LeChs1 is classified into class VI chitin synthases. Southern blot analysis indicated that Lechs1 is a single-copy gene per haploid genome and that L. edodes has no other highly homologous chitin synthase genes. Northern blot analysis revealed that Lechs1 is expressed throughout the whole stages of fruit-body formation of L. edodes, but its expression level gradually declines in a fruit body-maturation-dependent manner with highest expression in vegetative mycelia and fruit body at the early stage of maturation (immature fruit body). This is the first report on the isolation and characterization of the gene encoding a chitin synthase with a myosin motor-like domain from basidiomycetes.     

Extra-embryonic endoderm cells derived from ES cells induced by GATA Factors acquire the character of XEN cells

Background  

Three types of cell lines have been established from mouse blastocysts: embryonic stem (ES) cells, trophoblast stem (TS) cells, and extra-embryonic endoderm (XEN) cells, which have the potential to differentiate into their respective cognate lineages. ES cells can differentiate in vitro not only into somatic cell lineages but into extra-embryonic lineages, including trophectoderm and extra-embryonic endoderm (ExEn) as well. TS cells can be established from ES cells by the artificial repression of Oct3/4 or the upregulation of Cdx2 in the presence of FGF4 on feeder cells. The relationship between these embryo-derived XEN cells and ES cell-derived ExEn cell lines remains unclear, although we have previously reported that overexpression of Gata4 or Gata6 induces differentiation of mouse ES cells into extra-embryonic endoderm in vitro.