Distinct fucosylation of M cells and epithelial cells by Fut1 and Fut2, respectively, in response to intestinal environmental stress

The intestinal epithelium contains columnar epithelial cells (ECs) and M cells, and fucosylation of the apical surface of ECs and M cells is involved in distinguishing the two populations and in their response to commensal flora and environmental stress. Here, we show that fucosylated ECs (F-ECs) were induced in the mouse small intestine by the pro-inflammatory agents dextran sodium sulfate and indomethacin, in addition to an enteropathogen derived cholera toxin. Although F-ECs showed specificity for the M cell-markers, lectin Ulex europaeus agglutinin-1 and our monoclonal antibody NKM 16-2-4, these cells also retained EC-phenotypes including an affinity for the EC-marker lectin wheat germ agglutinin. Interestingly, fucosylation of Peyer’s patch M cells and F-ECs was distinctly regulated by α(1,2)fucosyltransferase Fut1 and Fut2, respectively. These results indicate that Fut2-mediated F-ECs share M cell-related fucosylated molecules but maintain distinctive EC characteristics, Fut1 is, therefore, a reliable marker for M cells.     

Protective effect of urocortin on 1-methyl-4-phenylpyridinium-induced dopaminergic neuronal death

Recent studies have indicated that the corticotropin releasing hormone (CRF)-related peptide, urocortin, restores key indicators of damage in animal models for Parkinson’s disease (PD). However, the molecular mechanism for the neuroprotective effect of urocortin is unknown. 1-Methy-4-phenylpyridinium (MPP⁺) induces dopaminergic neuronal death. In the present study, MPP⁺-induced neuroblastoma SH-SY5Y cell death was significantly attenuated by urocortin in a concentration-dependent manner. The protective effect of urocortin involved the activation of CRF receptor type 1, resulting in the increase of cyclic AMP (cAMP) levels. Various cAMP-enhancing reagents mimicked the effect of urocortin, while inhibitors for protein kinase A (PKA) blocked the effect of urocortin, strongly implicating the involvement of cAMP-PKA pathway in the neuroprotective effect of urocortin on MPP⁺-induced cell death. As the downstream of this signal pathway, urocortin promoted phosphorylation of both glycogen synthase kinase 3β and extracellular signal-regulated kinases, which are known to promote cell survival. These neuroprotective signaling pathways of urocortin may serve as potential therapeutic targets for PD.     

Two-dimensional gel analysis of stress proteins identified in Chironomus flaviplumus (Diptera: Chironomidae) exposed to 4-nonylphenol

Toxicity of 4-nonylphenol (4-NP) in the Chironomidae Chironomus flaviplumus was analyzed using a proteomics approach that involved identifying proteins by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Proteome analysis of 4-NP-treated samples on silver stained gels found alterations in the expression levels of three proteins compared with control samples. Hsp70 proteins, so-called stress proteins, were studied in Chironomus flaviplumus exposed to different concentrations of 4-nonylphenol (0, 30, 100, 150, 300 and 600 mg/L) in the laboratory and in the field in captured animals from site 1 (1 km from a chemical factory) and site 3 (16 km from a chemical factory). Hsp70 proteins were found in all samples tested, including controls, but differed in their expression levels. At more polluted sites (site 1), the samples treated with higher concentrations of 4-NP more strongly expressed Hsp70. 2-D spots were induced or enhanced in gels following injection of 4-NP. Therefore, the induction of stress protein expression in Chironomus flaviplumus, in particular Hsp70, can be used as a biomarker for the evaluation of environmental conditions.     

External Structures of the Antennae and Mouth Parts of the Fourth Instar of Chironomus flaviplumus and Chironomus salinarius (Diptera: Chironomidae)

Chironomidae is usually the most abundant macroinvetebrate in freshwater. They form an important part of the foodweb, and also have long been known as indicators of water quality. However, there is a great deal of difficulty in its identification. Such is due to the complexity of larval taxonomy. The external fine structures of the mouth parts and antennae of 4th instar larva C. flaviplumus and C. salinarius were examined using scanning electron microscopy (SEM). The antennae of the fourth instar larvae of C. flaviplumus and C. salinarius are short and composed of five segments. They consist of a scape, pedical, and three flagellar subsegments. The maxilla palps have 10 sensilla basiconica on its distal surface. They show the three morphological groups in the following numbers: six apical sensillae, three medial sensillae, and one lateral sensillae. The mandibles have strong apical and lateral teeth. These sensory structures are situated on the head capsule, each of which are represented with images to elucidate the identification of chironomidae.     

Effect of low oxygen tension on the biological characteristics of human bone marrow mesenchymal stem cells

Culture of mesenchymal stem cells (MSCs) under ambient conditions does not replicate the low oxygen environment of normal physiological or pathological states and can result in cellular impairment during culture. To overcome these limitations, we explored the effect of hypoxia (1 % O₂) on the biological characteristics of MSCs over the course of different culture periods. The following biological characteristics were examined in human bone marrow-derived MSCs cultured under hypoxia for 8 weeks: proliferation rate, morphology, cell size, senescence, immunophenotypic characteristics, and the expression levels of stemness-associated factors and cytokine and chemokine genes. MSCs cultured under hypoxia for approximately 2 weeks showed increased proliferation and viability. During long-term culture, hypoxia delayed phenotypic changes in MSCs, such as increased cell volume, altered morphology, and the expression of senescence-associated-β-gal, without altering their characteristic immunophenotypic characteristics. Furthermore, hypoxia increased the expression of stemness and chemokine-related genes, including OCT4 and CXCR7, and did not decrease the expression of KLF4, C-MYC, CCL2, CXCL9, CXCL10, and CXCR4 compared with levels in cells cultured under normoxia. In conclusion, low oxygen tension improved the biological characteristics of MSCs during ex vivo expansion. These data suggest that hypoxic culture could be a useful method for increasing the efficacy of MSC cell therapies.     

The GPSM2/LGN GoLoco motifs are essential for hearing

The planar cell polarity (PCP) pathway is responsible for polarizing and orienting cochlear hair cells during development through movement of a primary cilium, the kinocilium. GPSM2/LGN, a mitotic spindle-orienting protein associated with deafness in humans, is a PCP effector involved in kinocilium migration. Here, we link human and mouse truncating mutations in the GPSM2/LGN gene, both leading to hearing loss. The human variant, p.(Trp326*), was identified by targeted genomic enrichment of genes associated with deafness, followed by massively parallel sequencing. Lgn ^ΔC mice, with a targeted deletion truncating the C-terminal GoLoco motifs, are profoundly deaf and show misorientation of the hair bundle and severe malformations in stereocilia shape that deteriorates over time. Full-length protein levels are greatly reduced in mutant mice, with upregulated mRNA levels. The truncated Lgn ^ΔC allele is translated in vitro, suggesting that mutant mice may have partially functioning Lgn. Gαi and aPKC, known to function in the same pathway as Lgn, are dependent on Lgn for proper localization. The polarization of core PCP proteins is not affected in Lgn mutants; however, Lgn and Gαi are misoriented in a PCP mutant, supporting the role of Lgn as a PCP effector. The kinocilium, previously shown to be dependent on Lgn for robust localization, is essential for proper localization of Lgn, as well as Gαi and aPKC, suggesting that cilium function plays a role in positioning of apical proteins. Taken together, our data provide a mechanism for the loss of hearing found in human patients with GPSM2/LGN variants.     

Serum amyloid A1 is involved in amyloid plaque aggregation and memory decline in amyloid beta abundant condition

Transgenic Research - Alzheimer's disease (AD) is a neurodegenerative disorder, characterized by cognitive impairment, progressive neurodegeneration, and amyloid-β (Aβ) lesion. In the...