Publications by authors named "Shigeru Kakuta"

In light of the emerging importance of the gut microbiome in human health, there is a need to improve the colonization efficiency of therapeutic bacteria called probiotics. Despite their recognized potential, artificially administered bacteria exhibit poor colonization in the intestine, limiting their therapeutic efficacy. Addressing this challenge requires innovative strategies; however, reported examples are limited.

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Background: Transgenic (Tg) mice are widely used in biomedical research, and they are typically generated by injecting transgenic DNA cassettes into pronuclei of one-cell stage zygotes. Such animals often show unreliable expression of the transgenic DNA, one of the major reasons for which is random insertion of the transgenes. We previously developed a method called "pronuclear injection-based targeted transgenesis" (PITT), in which DNA constructs are directed to insert at pre-designated genomic loci.

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The clustered regularly interspaced short palindromic repeats (CRISPR) technology has made it possible to produce genome-edited (GE) animals more easily and rapidly than before. In most cases, GE mice are produced by microinjection (MI) or by in vitro electroporation (EP) of CRISPR reagents into fertilized eggs (zygotes). Both of these approaches require ex vivo handling of isolated embryos and their subsequent transfer into another set of mice (called recipient or pseudopregnant mice).

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HSF (heat shock transcription factor or heat shock factor) was discovered as a transcription factor indispensable for heat shock response. Although four classical HSFs were discovered in mammals and two major HSFs, HSF1 and HSF2, were cloned in the same year of 1991, only HSF1 was intensively studied because HSF1 can give rise to heat shock response through the induction of various HSPs' expression. On the other hand, HSF2 was not well studied for some time, which was probably due to an underestimate of HSF2 itself.

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Although hair loss is not a horrible disease, it sometimes reduces the patients' quality of life (QOL) and increases their mental stress. Currently, there is no effective treatment for hair loss. It is known that honeybee propolis has various biological activities, including stimulating the proliferation of hair matrix keratinocytes.

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Article Synopsis
  • The study investigates the link between intestinal inflammation and osteoporosis, focusing on a specific food-allergic model using mice that express OVA-specific T-cell receptors.* -
  • Findings show that feeding these mice an egg-white diet leads to bone loss and increased pathogenic T cells in both mesenteric lymph nodes (MLNs) and bone marrow.* -
  • The research highlights that IL-4 production from these immune cells plays a crucial role in promoting bone damage, with anti-IL-4 treatment showing potential to mitigate bone loss during initial inflammation.*
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Euglena gracilis is widely utilized as food or supplement to promote human and animal health, as it contains rich nutrients. In this study, we administered spray-dried powder of E. gracilis and paramylon, β-glucan stored in E.

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Understanding the host anti-fungal immunity induced by beta-glucan has been one of the most challenging conundrums in the field of biomedical research. During the last couple of decades, insights on the role of beta-glucan in fungal disease progression, susceptibility, and resistance have been greatly augmented through the utility of various beta-glucan cognate receptor-deficient mouse models. Analysis of dectin-1 knockout mice has clarified the downstream signaling pathways and adaptive effector responses triggered by beta-glucan in anti-fungal immunity.

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Proximal tubular cells (PTCs) are crucial for maintaining renal homeostasis, and tubular injuries contribute to progression of diabetic kidney disease (DKD). However, the roles of visceral adipose tissue-derived serine protease inhibitor (vaspin) in the development of DKD is not known. We found vaspin maintains PTCs through ameliorating ER stress, autophagy impairment, and lysosome dysfunction in DKD.

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The protective property of propolis across a wide spectrum of diseases has long been realized, yet the anti-tumor efficacy of this bioactive substance from Philippine stingless bees has remained poorly understood. Here, we showed the tumor-suppressing potential of crude ethanolic extract of Philippine stingless bee propolis (EEP) in in vitro models of gastric cancer highlighting the first indication of remarkable subtype specificity towards differentiated-type human gastric cancer cell lines but not the diffuse-type. Mechanistically, this involved the profound modulation of several cell cycle related gene transcripts, which correlated with the prominent cell cycle arrest at the G0/G1 phase.

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Article Synopsis
  • Gastric adenocarcinoma cells produce sulfomucins, but their exact function in cancer development is not well understood, prompting researchers to investigate using double-knockout (DKO) mice lacking these compounds.
  • DKO mice showed severe gastric erosion and developed gastritis cystica profunda (GCP) by three weeks old, indicating that the absence of sulfomucins leads to more severe gastric conditions at a young age.
  • Findings revealed that sulfomucins play a protective role against severe gastric erosion and inflammation but are not directly linked to the progression of gastric cancer itself, as evidenced by changes in gene expression in different age groups of DKO mice.
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The cytokines IL-17A and IL-17F have 50% amino-acid identity and bind the same receptor; however, their functional differences have remained obscure. Here we found that Il17f mice resisted chemically induced colitis, but Il17a mice did not, and that Il17f CD45RBCD4 T cells induced milder colitis in lymphocyte-deficient Rag2 mice, accompanied by an increase in intestinal regulatory T cells (T cells). Clostridium cluster XIVa in colonic microbiota capable of inducing T cells was increased in both Il17f mice and mice given transfer Il17f T cells, due to decreased expression of a group of antimicrobial proteins.

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β-Glucan refers to a heterogeneous group of chemically defined storage polysaccharides containing β-(1,3)-d-linked glucose polymers with branches connected by either β-(1,4) or β-(1,6) glycosidic linkage. To date, an extensive amount of scientific evidence supports their multifunctional biological activities, but their potential involvement in the progression of premalignant lesions remains to be clarified. A4gnt KO mice that lack α1,4-N-acetylglucosamine-capped O-glycans in gastric gland mucin are a unique animal model for gastric cancer because the mutant mice spontaneously develop gastric cancer through hyperplasia-dysplasia-adenocarcinoma sequence.

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F-box and WD40 domain protein 7 (FBXW7) is a component of the SKP1-CUL1-F-box protein (SCF) complex that mediates the ubiquitination of diverse oncogenic target proteins. The exploration of FBXW7 mutations in human primary cancer has revealed three mutation hotspots at conserved arginine residues (Arg, Arg, and Arg) in the WD40 domain, which are critical for substrate recognition. To study the function of human FBXW7 , the most frequent mutation in human malignancies, we generated a novel conditional knockin mouse line of murine Fbxw7 corresponding to human FBXW7 .

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PKC-potentiated phosphorylation-dependent inhibitory protein of protein phosphatase 1 (CPI-17), an endogenous myosin phosphatase inhibitory protein, is considered a key molecule for Ca sensitization of the contractile apparatus. Here, we have used clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 to generate CPI-17-deficient [knockout (KO)] and threonine 38 (T38)-phospho-resistant mice [threonine mutant into alanine (TA)], and then effects of CPI-17 on vascular contractility in vitro and mean blood pressure (MBP) in vivo were investigated. In isolated thoracic aorta, phorbol 12, 13-dibutyrate induced a sustained contraction of wild-type (WT) mice, whereas no contraction showed from TA or KO mice.

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Herpes simplex virus-1 (HSV-1) is the most common cause of sporadic viral encephalitis, which can be lethal or result in severe neurological defects even with antiviral therapy. While HSV-1 causes encephalitis in spite of HSV-1-specific humoral and cellular immunity, the mechanism by which HSV-1 evades the immune system in the central nervous system (CNS) remains unknown. Here we describe a strategy by which HSV-1 avoids immune targeting in the CNS.

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An endoscopic examination revealed a mass in the distal esophagus of a 9-year-old intact male bulldog. Histopathologically, the mass was composed of cuboidal to columnar neoplastic epithelial cells and extended from the squamous epithelium of the esophageal mucosa, indicating that the tumor was derived from Barrett's esophagus. Moreover, highly atypical foci that exhibited a cribriform pattern and high mitotic indices were also observed.

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Sickness responses to lipopolysaccharide (LPS) were examined in mice with deletion of the interleukin (IL)-1 type 1 receptor (IL-1R1). IL-1R1 knockout (KO) mice displayed intact anorexia and HPA-axis activation to intraperitoneally injected LPS (anorexia: 10 or 120µg/kg; HPA-axis: 120µg/kg), but showed attenuated but not extinguished fever (120µg/kg). Brain PGE synthesis was attenuated, but Cox-2 induction remained intact.

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Probiotics, such as lactic acid bacteria (LAB) and var. , have been shown to modulate immune responses. It is important to understand how probiotic bacteria impact intestinal epithelial cells (IECs), because IECs are the first line of defense at the mucosal surface barrier and their activities substantially affect the gut microenvironment and immunity.

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Hematopoietic stem cell (HSC) transplantation (HSCT) for malignancy requires toxic pre-conditioning to maximize anti-tumor effects and donor-HSC engraftment. While this induces bone marrow (BM)-localized inflammation, how this BM environmental change affects transplanted HSCs in vivo remains largely unknown. We here report that, depending on interval between irradiation and HSCT, residence within lethally irradiated recipient BM compromises donor-HSC reconstitution ability.

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Mammalian zygote-mediated genome-engineering by CRISPR/Cas is currently used for the generation of genome-modified animals. Here we report that a Streptococcus thermophilus-1 derived orthologous CRISPR/Cas system, which recognizes the 5'-NNAGAA sequence as a protospacer adjacent motif (PAM), is useful in mouse zygotes and is applicable for generating knockout mice (87.5%) and targeted knock-in mice (45.

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The complement system is important for the host defence against infection as well as for the development of inflammatory diseases. Here we show that C1q/TNF-related protein 6 (CTRP6; gene symbol C1qtnf6) expression is elevated in mouse rheumatoid arthritis (RA) models. C1qtnf6(-/-) mice are highly susceptible to induced arthritis due to enhanced complement activation, whereas C1qtnf6-transgenic mice are refractory.

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Dectin-1, the receptor for β-glucans, protects the host against fungal infection; however, its role in intestinal immunity is incompletely understood. We found that Dectin-1-deficient (Clec7a(-/-)) mice were refractory to both dextran sodium sulfate (DSS)- and CD45RB(high)CD4(+) T cell-induced colitis, and that this resistance was associated with an increase in regulatory T (Treg) cells. The proportion of lactobacilli, especially Lactobacillus murinus, in the commensal microflora was increased in Clec7a(-/-) mouse colons, and accompanied by a decrease in antimicrobial peptides induced by Dectin-1 signaling.

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Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor containing a carbohydrate recognition domain in its extracellular portion and an immunoreceptor tyrosine–based inhibitory motif, which transduces negative signals into cells, in its cytoplasmic portion. Previously, we showed that Dcir(–/–) mice spontaneously develop autoimmune diseases such as enthesitis and sialadenitis due to excess expansion of dendritic cells (DCs), suggesting that DCIR is critically important for the homeostasis of the immune system. In this report, we analyzed the role of DCIR in the development of experimental autoimmune encephalomyelitis (EAE), an autoimmune disease model for multiple sclerosis.

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