Human endogenous retroviruses (HERVs) and other long terminal repeat (LTR)-type retrotransposons (HERV/LTRs) have regulatory elements that possibly influence the transcription of host genes. We systematically identified and characterized these regulatory elements based on publicly available datasets of ChIP-Seq of 97 transcription factors (TFs) provided by ENCODE and Roadmap Epigenomics projects. We determined transcription factor-binding sites (TFBSs) using the ChIP-Seq datasets and identified TFBSs observed on HERV/LTR sequences (HERV-TFBSs). Overall, 794,972 HERV-TFBSs were identified. Subsequently, we identified “HERV/LTR-shared regulatory element (HSRE),” defined as a TF-binding motif in HERV-TFBSs, shared within a substantial fraction of a HERV/LTR type. HSREs could be an indication that the regulatory elements of HERV/LTRs are present before their insertions. We identified 2,201 HSREs, comprising specific associations of 354 HERV/LTRs and 84 TFs. Clustering analysis showed that HERV/LTRs can be grouped according to the TF binding patterns; HERV/LTR groups bounded to pluripotent TFs (e.g., SOX2, POU5F1, and NANOG), embryonic endoderm/mesendoderm TFs (e.g., GATA4/6, SOX17, and FOXA1/2), hematopoietic TFs (e.g., SPI1 (PU1), GATA1/2, and TAL1), and CTCF were identified. Regulatory elements of HERV/LTRs tended to locate nearby and/or interact three-dimensionally with the genes involved in immune responses, indicating that the regulatory elements play an important role in controlling the immune regulatory network. Further, we demonstrated subgroup-specific TF binding within LTR7, LTR5B, and LTR5_Hs, indicating that gains or losses of the regulatory elements occurred during genomic invasions of the HERV/LTRs. Finally, we constructed dbHERV-REs, an interactive database of HERV/LTR regulatory elements (http://herv-tfbs.com/). This study provides fundamental information in understanding the impact of HERV/LTRs on host transcription, and offers insights into the transcriptional modulation systems of HERV/LTRs and ancestral HERVs.

β-Glucans are a class of polysaccharides consisting of D-glucose units that are polymerized primarily via the β-1,3 glycosidic bonds, in addition to the β-1,4 and/or β-1,6 bonds. They are present in various food products such as cereals, mushrooms, and seaweeds and are known for their numerous effects on the human body, depending on their structures, which are diverse. The major physicochemical properties of β-glucans include their antioxidant property, which is responsible for the scavenging of reactive oxygen species, and their role as dietary fiber for preventing the absorption of cholesterol, for promoting egestion, and for producing short-chain fatty acids in the intestine. Dietary β-glucans also exert immunostimulatory and antitumor effects by activation of cells of the mucosal immune system via β-glucan receptors, such as dectin-1. In this review, we elaborate upon the diversity of the structures and functions of β-glucans present in food, along with discussing their proposed mechanisms of action. In addition to the traditional β-glucan-containing foods, recent progress in the commercial mass cultivation and supply of an algal species, Euglena gracilis, as a food material is briefly described. Mass production has enabled consumption of paramylon, a Euglena-specific novel β-glucan source. The biological effects of paramylon are discussed and compared with those of other β-glucans.

The gene ybhA of Escherichia coli encodes a phosphatase that has an in vitro specificity to dephosphorylate pyridoxal 5¢ ¢ ¢ ¢ ¢-phosphate (PLP or vitamin B 6 ), a co-factor for aminotransferases and other enzymes. In this study, we found that excess pyridoxal (PL) in a minimal medium resulted in excess PLP in vivo and growth inhibition, which was alleviated by YbhA overproduction. Conversely, the YbhA overproduction resulted in PLP shortage in vivo and the correlated reduction in growth rate, which was significantly negated by PL in the medium. In addition, the overproduction of a PL kinase, PdxK or PdxY, was inhibitory to cell growth only in the absence of the functional ybhA gene, and the growth defects were alleviated by casamino acids in the medium, which suggested that both the shortage of, and excess, PLP resulted in the disturbance of amino acid metabolism and cell growth, as revealed by a metabolome analysis.

Progression to non‐alcoholic steatohepatitis (NASH) manifests as hepatitis, fibrosis, and sometimes carcinoma, resulting in liver failure. Various clinical trials have indicated that several pharmacological agents, including angiotensin II receptor blockers (ARBs) or farnesoid X receptor (FXR) agonists, are effective in NASH treatment. In addition, functional foods are expected to be important alternatives for treating or preventing NASH. Recently, focus has been directed toward microalgae as dietary supplements, mainly for lifestyle‐related diseases, because they contain various nutrients and functional ingredients. Specifically, a unicellular microalga Euglena gracilis stores a unique β‐1,3‐glucan particle called paramylon that stimulates the immune system. In this study, we evaluated the effects of Euglena and paramylon on NASH in Stelic Animal Model (STAM) mice using Sirius red staining and confirmed that oral administration of Euglena or paramylon inhibits the process of liver fibrosis. Moreover, compared with controls, paramylon decreased non‐alcoholic fatty liver disease (NAFLD) activity scores related to inflammation. These results indicate that the oral administration of Euglena and paramylon inhibits fibrosis and ameliorates NASH.