Biomedical Research-tokyo最新文献

Gastrin and CCK (cholecystokinin), gut hormones first secreted after postprandial stages, share the C-terminal amino acids and some types of receptors to be stimulated. Both types of hormone-secreting cells are typical open-type cells which detect foods and their digested elements in the lumen and regulate the secretion of gastric acid and digestive enzymes, gut motility, and satiety. Gastrin cell granules are characterized by their heterogenous ultrastructure within the cell, while CCK cell granules show a uniform ultrastructural figure. Gastrin cells are equipped with peptone receptor GPR92, amino acid receptor GPRC6A, and a Ca-sensing receptor. In addition to nutrient receptors, the release of CCK is regulated by a unique negative feedback mechanism. Development of an antibody for CCK-specific receptor (CCK-1R) has revealed its exact localization throughout the body, but specific antibodies against CCK-2R remain unavailable. Gastrin affects differentiation and proliferation-including cancer cells, while CCK possesses trophic effects to target tissues. CCK is a peripheral satiety signal and acts either via the vagus or directly on the dorsal medulla via CCK-1R. In this review, endocrine cells secreting these unique and so-called old gut hormones are described on a morphological basis.

Seizure-like burst activities are induced by blockade of GABAA and/or glycine receptors in various spinal ventral roots of brainstem-spinal cord preparation from neonatal rodents. We found that this is not applicable to the phrenic nerve and that a new inhibitory descending pathway may suppress seizure-like activity in the phrenic nerve. Experiments were performed in brainstem-spinal cord preparation from newborn rats (age: 0-1 day). Left phrenic nerve and right C4 activities were recorded simultaneously. When GABAA and glycine receptors were blocked by 10 μM bicuculline and 10 μM strychnine (Bic+Str), seizure-like burst activities appeared in the fourth cervical ventral root (C4) but not the phrenic nerve. After making a transverse section at C1, the inspiratory burst activity disappeared from both C4 and the phrenic nerve, whereas seizure-like activity appeared in both nerves. We hypothesized that inhibitory descending pathways other than those via GABAA and/or glycine receptors (from the medulla to the spinal cord) work to avoid disturbance of regular respiratory-related diaphragm contraction by seizure-like activity. We found that cannabinoid receptor antagonist, AM251 was effective for the induction of seizure-like activity by Bic+Str in the phrenic nerve in brainstem-spinal cord preparation. Cannabinoid receptors may be involved in this descending inhibitory system.

GP (glycoprotein)-2, originally identified as a predominant membranous component of pancreatic acinar cells, has attracted the interest of researchers in mucosal immunology for its role as a functional molecule specific for antigen-sampling cells in the intestinal Peyer's patches. GP2 is involved in the detection of pathological bacteria and is also histologically useful for the identification of the M cell lineage and their differentiation in lymphoid tissues. Subsequent immunohistochemistry for GP2 has revealed a broad distribution of M cells and related cells in the nasopharyngeal lymphoid tissues, conjunctiva, tear duct, and airway. Especially, GP2 cells in the paranasal sinuses and tear duct have been identified as novel types of epithelial cells. The systematic administration of RANKL can induce extra-M cells in conventional epithelia of body. The production and release of GP2 by conjunctival goblet cells and several mucous glands suggests leading roles for mucous cells in protection, including the entrapment of microorganisms for infections. The ocular surface and conjunctiva are connected to the lacrimal sac, nasolacrimal duct, and further nasal cavity, comprising another canal that passes through the body. The broad distribution of GP2-expressingcells may indicate its function as a new guardian in the intestine, eyes, and nose, all of which are exposed to external milieu.

Whole genome sequencing (WGS) in cancer genomics has become widespread with recent technological innovations, and the amount and types of information obtained from WGS are increasing rapidly. Appropriate interpretation of results is becoming increasingly important in clinical applications. This study aimed to evaluate the accuracy of tumor content estimation and its impact on somatic variant detection, using 100 simulated tumor samples covering 10-100% tumor content constructed from the sequencing data of cell line models. Extensive analysis revealed that the estimation results varied among computational analytical methods. Notably, there was a large discrepancy in low tumor content (≤ 30%). The reproducibility decreased in cases wherein chromosome-scale copy number changes were observed in normal cells. The minimum tumor content required to detect somatic alterations was estimated to be 10-30%. Identification of whole genome doubling was achieved with the lowest tumor content, followed by single nucleotide variation/insertion or deletion, structural variation, and copy number variation. Tumor content had a significantly higher impact on the false negatives than the false positives in variant calls. Results should be interpreted cautiously for samples wherein tumor content is a concern. These results can form the basis of developing important guidelines for evaluating cancer WGS.

In recent years, bacterial DNA in formalin-fixed paraffin-embedded (FFPE) samples has been recognized as a valuable bioresource for microbiota studies. This study aimed to examine the effect of the FFPE process on microbiota profiling to evaluate whether FFPE samples could serve as an alternative bioresource to fresh samples in oral microbiota studies. Fresh saliva was collected from nine subjects. The pellets obtained by centrifuging the collected saliva were fixed in formalin, then dehydrated and embedded in paraffin to prepare FFPE samples. The abundance of the hypervariable regions V1-9, V1-2, and V3-4 of the 16S rRNA gene in fresh and FFPE samples was relatively compared. In addition, microbiota profiling was performed to compare the results between the two sample types. The results showed that the FFPE process resulted in a certain degree of fragmentation of the 16S rRNA gene. However, the V1-2 region was relatively well-preserved compared to the V1-9 and V3-4 regions, suggesting that short regions are suitable targets for oral microbiota analysis. Importantly, there were no significant differences in alpha and beta diversity of microbiota between fresh and FFPE samples, and microbiota profiles were similar between the two sample types, suggesting that FFPE samples could be a valuable bioresource for oral microbiota studies.

Trace amines (TAs) in the nervous system bind to TA-associated receptors (TAARs) and are involved in the regulation of monoaminergic functions. Among TAAR subtypes, TAAR1 has been implicated in the development of neurological disorders, such as schizophrenia. The present study investigated the effects of the TAAR1 agonist, 3-iodothyronamine (T1AM) on cerebral arterioles using fluctuations in the intracellular concentration of Ca2+ ([Ca2+]i) as an index of contractile responses. In cerebral arterioles, most of the TAAR agonists did not increase [Ca2+]i, while only T1AM elevated [Ca2+]i in vascular smooth muscle cells. This increase involved extracellular Ca2+ influx through T-type Ca2+ channels and inositol trisphosphate- and ryanodine-receptor-mediated Ca2+ release from intracellular stores. The inhibition of the cAMP sensor, exchange protein directly activated by cAMP (Epac) 2, and calmodulin kinase (CaMK) II strongly inhibited Ca2+ elevations. The present study revealed that T1AM acted not only on the TAAR1 receptor as previously suggested, but also on other G-protein coupled receptors and/or signal transduction systems to increase intracellular Ca2+ in cerebral arteriole smooth muscle cells. These results suggest that when using T1AM in clinical practice, attention should be paid to the early rise in blood pressure.

Aneuploidy has been recognized as one of hallmark of tumorigenesis since the early 20th century. Recent developments in structural variation analysis in the human genome have revealed the diversity of aneuploidy in cancer. However, the effects of gene mutation and expression in tumors on aneuploidy remain poorly understood. Here, we performed whole exome analysis of over 5,000 Japanese cancer cases and investigated the impact of somatic mutations and gene expression alterations on aneuploidy. First, we evaluated tumor content and genomic alterations that could influence aneuploidy. Next, we compared the aneuploidy frequency in 18 cancer types and observed that TP53 mutations were associated with the aneuploidy on specific chromosomes in colorectal and gastric cancers. Finally, we used expression analysis to isolate pathways involved in aneuploidy accumulation from tumors without TP53 mutations. Chromosomal instability and cell cycle aberration were associated with aneuploidy in TP53 wild-type tumors, and 26 commonly upregulated genes were identified in aneuploidy-high solid tumors without TP53 mutations. Among them, two cancer-related genes (CENPA and PBK) were involved in aneuploidy. Our integrated analysis revealed that both TP53 mutations and transcriptomic alterations independent of somatic mutations affect aneuploidy accumulation. Our findings will facilitate further understanding of diverse aneuploidies in the tumorigenesis.

Electrical stimulation (ES) is effective for disuse-induced muscle atrophy. However, the acute effect of ES on muscle protein synthesis (MPS) and muscle protein breakdown (MPB) remains unclear. We investigated the effect of a single-session ES treatment on mTORC1 signaling, MPS, and MPB in the soleus muscle of 2-week hindlimb unloaded rats. Sprague Dawley rats (n = 12 male) were randomly divided into control (CON) and hindlimb unloaded (HU) groups. After 2 weeks, the right soleus muscle was percutaneously stimulated and underwent supramaximal isometric contractions. The left soleus muscle served as an internal control. We collected soleus muscle samples 6 h after ES. Two weeks of HU decreased p70S6K and S6rp activation, downstream factors for mTORC1 signaling, and SUnSET method-assessed MPS, but increased the LC3-II/I ratio, an indicator of autophagy. ES on disused muscle successfully activated mTORC1 signaling but did not affect MPS. Contrary, ES decreased ubiquitinated proteins expression and LC3B-II/I ratio. HU might affect mTORC1 activation and MPS differently in response to acute ES possibly due to excessive ROS production caused by ES. Our findings suggest that ES applied to disused skeletal muscles may suppress MPB, but its effect on MPS appears to be attenuated.

Interleukin-33 (IL-33) is a member of the IL-1 cytokine family that has been studied primarily in the context of type 2 immune responses. Recent reports suggest that IL-33 also enhances the func- tions of various immune cells and contributes to the development of different inflammatory diseas- es. Interestingly, IL-33 and its receptor ST2 axis exerted either inhibitory or promotional effects on alveolar bone loss in various periodontitis models. Using a mouse model of ligature-induced periodontitis, we found that the levels of mRNAs encoding IL-33 and other inflammatory cyto- kines (IL-1α, IL-1β, IL-6, and TNFα) were augmented in gingival tissues of wild-type (WT) mice, and that the alveolar bone loss amount was lower in IL-33-deficient than WT mice. The numbers and proportions of IFN-γ-producing CD8+ T and regulatory T cells were decreased while those of Th17 cells were increased in the draining lymph nodes of IL-33-deficient mice compared to WT mice. Additionally, the level of RNA encoding an osteoclastogenic molecule, i.e., receptor activa- tor of nuclear factor kappa-B ligand (RANKL), in ligated gingival tissue was higher in IL-33-defi- cient than WT mice. These results suggest that IL-33 is involved in alveolar bone loss in the ligature-induced periodontitis model, although IL-33 may inhibit osteoclast differentiation.

This study mainly used human VSMCs and ECs cultured in vitro to investigate whether exosomes (Exos) are involved in the communication between ECs and VSMCs under hypoxia, and to explore the role and mechanism of ECs-derived exosomes in the abnormal proliferation of VSMCs. VSMCs proliferation and migration were assessed by a series of cell function assays after culturing VSMCs alone or co-culturing ECs under hypoxia or normoxia. Next, exosomes were extracted from ECs under hypoxia or normoxia and characterized. We then introduced ECs-Exos to observe their effects on VSMCs proliferation and migration, and further evaluated the expression of transforming growth factor-beta receptor 1 (TGFBR1) pathway-related proteins. Finally, the effect of ECs-Exos on VSMCs function was evaluated after knocking down TGFBR1 in ECs. VSMCs treated with ECs-Exos exhibited increased proliferation and migration ability in hypoxic environment, and the expression of TGFBR1 pathway-related proteins was upregulated. Administration of ECs-Exos with TGFβ1 knockdown conspicuously reversed the promoting effects of ECs-Exos on cell proliferation and migration under hypoxia. In summary, hypoxia affected the secretion of extracellular vesicles by endothelial cells, which can be internalized by VSMCs and accelerate the abnormal proliferation and migration of VSMCs by delivering TGFBR1.