Temperature-responsive cell culture surfaces, which modulate cell attachment/detachment characteristics with temperature, have been used to fabricate cell sheets. Extensive study on fabrication of ...cell sheet with the temperature-responsive cell culture surface, manipulation, and transplantation of the cell sheet has established the interdisciplinary field of cell sheet engineering, in which engineering, biological, and medical fields closely collaborate. Such collaboration has pioneered cell sheet engineering, making it a promising and attractive technology in tissue engineering and regenerative medicine. This review introduces concepts of cell sheet engineering, followed by designs for the fabrication of various types of temperature-responsive cell culture surfaces and technologies for cell sheet manipulation. The development of various methods for the fabrication of temperature-responsive cell culture surfaces was also summarized. The availability of cell sheet engineering for the treatment and regeneration of damaged human tissue has also been described, providing examples of the clinical application of cell sheet transplantation in humans.
Background
Recurrent abdominal pain is a common and costly health‐care problem attributed, in part, to visceral hypersensitivity. Increasing evidence suggests that gut bacteria contribute to ...abdominal pain perception by modulating the microbiome‐gut‐brain axis. However, specific microbial signals remain poorly defined. γ‐aminobutyric acid (GABA) is a principal inhibitory neurotransmitter and a key regulator of abdominal and central pain perception from peripheral afferent neurons. Although gut bacteria are reported to produce GABA, it is not known whether the microbial‐derived neurotransmitter modulates abdominal pain.
Methods
To investigate the potential analgesic effects of microbial GABA, we performed daily oral administration of a specific Bifidobacterium strain (B. dentiumATCC 27678) in a rat fecal retention model of visceral hypersensitivity, and subsequently evaluated pain responses.
Key Results
We demonstrate that commensal Bifidobacterium dentium produces GABA via enzymatic decarboxylation of glutamate by GadB. Daily oral administration of this specific Bifidobacterium (but not a gadB deficient) strain modulated sensory neuron activity in a rat fecal retention model of visceral hypersensitivity.
Conclusions & Inferences
The functional significance of microbial‐derived GABA was demonstrated by gadB‐dependent desensitization of colonic afferents in a murine model of visceral hypersensitivity. Visceral pain modulation represents another potential health benefit attributed to bifidobacteria and other GABA‐producing species of the intestinal microbiome. Targeting GABAergic signals along this microbiome‐gut‐brain axis represents a new approach for the treatment of abdominal pain.
Increasing evidence suggests that gut bacteria contribute to abdominal pain perception by modulating the microbiome‐gut‐brain axis. Here, we demonstrate that commensal Bifidobacterium dentium produces GABA via enzymatic decarboxylation of glutamate by GadB. Daily oral administration of this specific Bifidobacterium (but not a gadB deficient) strain modulated sensory neuron activity in a rat fecal retention model of visceral hypersensitivity.
Intramembrane-cleaving proteases (I-CLiPs) are a group of membrane-associated proteases with a unique feature: they are believed to cleave their substrate within the hydrophobic lipid bilayer, even ...though peptide bond hydrolysis requires a water molecule. Escherichia coli RseP, which belongs to the S2P zinc metalloprotease family of I-CLiPs, plays an essential role in activation of a cell envelope stress response through cleavage of anti-σ
protein RseA, a single-span transmembrane protein. A recent study showed that it also cleaves remnant signal peptides generated upon membrane translocation of secretory proteins. Here, we describe several methods for characterization of the proteolytic functions and structure of RseP mainly in vivo, including a proteolytic activity assay using model substrates, an in vitro analysis of cleavage of signal peptides in a detergent solution and in the membrane vesicles, structural analysis of membrane-embedded RseP based on the thiol modifiability of introduced cysteine residues, and the protein interaction analysis by in vivo cross-linking protocols.
SOX transcription factors are essential for embryonic development and play critical roles in cell fate determination, differentiation and proliferation. We previously reported that the SOX2 protein ...is expressed in normal gastric mucosae but downregulated in some human gastric carcinomas. To clarify the roles of SOX2 in gastric carcinogenesis, we carried out functional characterisation of SOX2 in gastric epithelial cell lines. Exogenous expression of SOX2 suppressed cell proliferation in gastric epithelial cell lines. Flow cytometry analysis revealed that SOX2-overexpressing cells exhibited cell-cycle arrest and apoptosis. We found that SOX2-mediated cell-cycle arrest was associated with decreased levels of cyclin D1 and phosphorylated Rb, and an increased p27(Kip1) level. These cells exhibited further characteristics of apoptosis, such as DNA laddering and caspase-3 activation. SOX2 hypermethylation signals were observed in some cultured and primary gastric cancers with no or weak SOX2 expression. Among the 52 patients with advanced gastric cancers, those with cancers showing SOX2 methylation had a significantly shorter survival time than those without this methylation (P=0.0062). Hence, SOX2 plays important roles in growth inhibition through cell-cycle arrest and apoptosis in gastric epithelial cells, and the loss of SOX2 expression may be related to gastric carcinogenesis and poor prognosis.
In Escherichia coli, like in any organism, the cytoplasmic (inner or plasma) membrane proteins play essential roles in transport of small and macro-molecules as well as in transmission of ...environmental signals across the membrane. Their quality control is critically important for growth and survival of the cell. However, our knowledge about the players and mechanisms of the system is still limited. This review focuses on proteolytic quality control of membrane proteins, in which two membrane-integrated proteases, FtsH and HtpX, with different modes of action, play central roles. The prohibitin family membrane protein complexes (HflKC and QmcA) contribute to the quality control system as a regulatory factor of FtsH and also as a possible membrane-chaperone. Failure of the quality control system to function normally leads to accumulation of malfolded cytoplasmic membrane proteins, which in turn activate the stress response pathways previously believed to be specialized for sensing protein abnormalities outside the cytoplasmic membrane. In fact, many of the cytoplasmic membrane quality control factors are stress induced. Further characterization of them as well as of the stress-sensing mechanisms would prove useful to obtain an integrated picture of the membrane protein quality control system.
Diffuse-type gastric cancer (DGC) exhibits rapid disease progression and a poor prognosis. There are no effective serum biomarkers for early detection of DGC. We have established an E-cadherin/p53 ...double conditional knockout (DCKO) mouse line that recapitulates human DGC morphologically and molecularly. In this study we tried to identify circulating microRNAs (miRNAs) as non-invasive biomarkers for DGC diagnosis using DCKO mice.
We performed miRNA microarray and quantitative reverse transcription-PCR analyses of tissue and serum samples from DCKO mice with DGC and age-matched littermate controls.
Comparative analyses showed that mouse and human primary gastric cancers have similar miRNA expression patterns. Next, we selected some candidate miRNAs highly expressed in sera and cancer tissues of DCKO mice for further evaluation. TaqMan quantitative RT-PCR analyses indicated that four of them, miR-103, miR-107, miR-194 and miR-210, were significantly upregulated in sera of both early and advanced-stage DGC-bearing mice compared with in corresponding controls. Receiver-operating characteristic curve analyses demonstrated that these four miRNAs can discriminate DGC-positive cases from normal ones with high sensitivity and specificity.
These observations suggest that this mouse model of DGC is useful for identifying serum biomarkers, and we found circulating miRNAs that can accurately detect DGC at an early stage.
Heavy metals pollution has become one of the most serious environmental problems nowadays. Studies on the environmental pollution indicate that water pollution by heavy metals ions has reached ...unprecedented levels over the past decade in many countries, with highlights to African countries. Removal of these toxic metals from contaminated water can improve human being life quality and prevent from their adverse effects. This study aims to text the ability of magnetic activated carbon (MAC) and MAC coated with wastes of colloidal silica (MACSi) for adsorption of copper, manganese and zinc ions from water and its separation from water using magnetic separation technique. The adsorption results of MAC and MACSi showed that MACSi was more effective to adsorb the ions than MAC. FT-IR spectrum and XRD pattern of MACSi indicated that silica coating onto MAC surface is in amorphous form.
Jumonji domain-containing protein 2B (JMJD2B), directly targeted by hypoxia-inducible factor 1α, maintains the histone methylation balance important for the transcriptional activation of many ...oncogenes. Jumonji domain-containing protein 2B has been implicated in colorectal cancer (CRC) progression; however, the mechanism remains unclear.
Immunofluorescence and western blotting detected phosphorylated histone H2AX, characteristic of double-strand breaks, and comet assay was used to investigate DNA damage, in CRC cells after JMJD2B small interfering RNA (siRNA) transfection. We assessed the resulting in vitro responses, that is, cell cycle progression, apoptosis, and senescence coupled with JMJD2B silencing-induced DNA damage, studying the regulatory role of signal transducers and activators of transcription 3 (STAT3). The JMJD2B silencing anti-cancer effect was determined using an in vivo CRC xenograft model.
Jumonji domain-containing protein 2B knockdown induced DNA damage via ataxia telangiectasia-mutated (ATM) and ATM and Rad3-related pathway activation, resulting in cell cycle arrest, apoptosis, and senescence in both normoxia and hypoxia. Signal transducers and activators of transcription 3 suppression by JMJD2B silencing enhanced DNA damage. Intratumoural injection of JMJD2B siRNA suppressed tumour growth in vivo and activated the DNA damage response (DDR).
Jumonji domain-containing protein 2B has an essential role in cancer cell survival and tumour growth via DDR mediation, which STAT3 partially regulates, suggesting that JMJD2B is a potential anti-cancer target.
Gold nanoparticles (1−10 nm size range) were prepared with an appreciably narrow size distribution by in situ reduction of HAuCl4 in the presence of heterobifunctional poly(ethylene glycol) (PEG) ...derivatives containing both mercapto and acetal groups (α-acetal-ω-mercapto-PEG). The α-acetal-PEG layers formed on gold nanoparticles impart appreciable stability to the nanoparticles in aqueous solutions with elevated ionic strength and also in serum-containing medium. The PEG acetal terminal group was converted to aldehyde by gentle acid treatment, followed by the reaction with p-aminophenyl-β-d- lactopyranoside (Lac) in the presence of (CH3)2NHBH3. Lac-conjugated gold nanoparticles exhibited selective aggregation when exposed to Recinus communis agglutinin (RCA120), a bivalent lectin specifically recognizing the β-d-galactose residue, inducing significant changes in the absorption spectrum with concomitant visible color change from pinkish-red to purple. Aggregation of the Lac-functionalized gold nanoparticles by the RCA120 lectin was reversible, recovering the original dispersed phase and color by addition of excess galactose. Further, the degree of aggregation was proportional to lectin concentration, allowing the system to be utilized to quantitate lectin concentration with nearly the same sensitivity as ELISA. This simple, yet highly effective, derivatization of gold nanoparticles with heterobifunctional PEG provides a convenient method to construct various colloidal sensor systems currently applied in bioassays and biorecognition.
Direct heat and moisture conditions can lead to discomfort for humans and animals and can decrease health performance. The discomfort index or temperature-humidity index (THI) represents an important ...indicator that measures the heat sensed by humans for different climate conditions. In extreme situations, heatstroke may occur, which in unfortunate cases will lead to death. Many research studies have been conducted on the urban heat island (UHI) phenomenon, although a majority of such work focuses on regional-scale analyses and emphasizes the thermal trend through larger administrative units. Fewer micro-scale analyses have been performed at the local scale to detect the potential area for increased THI within a city. This work seeks to estimate the THI at the micro-scale level by utilizing the thermal camera on-board of unmanned aerial systems (UASs). Thermal information of the surface and visual images are collected by the UAS, while a thermohygrometer is used to collect the air temperature and the relative humidity at the ground surface for ground truth information. Solar radiation and wind exposure modeled from digital surface model (DSM) and normalized difference vegetation index (NDVI) data are used as explanatory variables, and a random forest machine learning method is implemented to model the spatial distribution of the THI. The results and discussion will provide future possibilities for micro-scale analyses of the UHI.
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