Nuclear AgNOR protein enhancement in nucleoplasms of peripheral blood lymphocytes of babies/children with down syndrome

Down syndrome (DS) is one of the most common chromosomal disorders. The factors contributing to the mental retardation together with other defects in this syndrome have not been fully explained. Individuals with DS have extra rRNA gene family since they carry an extra chromosome 21. The few reports available are on the relationship between the nucleolus organizer regions (NORs) and DS phenotype. The in vivo regulation of NORs expression on the extra chromosome 21 is not completely understood. Previous studies have shown that nucleoli of lymphocytes from infants (mostly neonates) with DS contain more in vivo and in vitro nucleolar AgNOR proteins when compared with healthy infants. The objective of this study is to compare the in vivo nuclear AgNOR protein level in nucleoplasms (also called as karyoplasm) of nonstimulated peripheral blood lymphocytes from babies/children with DS and healthy controls. Peripheral blood samples obtained from 20 babies/children with DS and 20 matched healthy controls were smeared on clean glass slides and then AgNOR staining was performed. The AgNOR protein level in nucleoplasms of lymphocytes from both groups was calculated using a computer program. Nearly 100 interphase nuclei per individual were analysed. Average nuclear AgNOR protein levels in nucleoplasms of lymphocytes from babies/children with DS were found to be significantly higher than those of the controls (P < 0.001). On the basis of our present results, we propose that the increase of nuclear AgNOR protein in in vivo conditions may contribute to the formation of DS phenotypes. Microsc. Res. Tech. 79:133–139, 2016. © 2016 Wiley Periodicals, Inc.     

Influence of the microenvironment on gene and protein expression of odontogenic-like and osteogenic-like cells

Progenitor cells play an important biological role in tooth and bone formation, and previous analyses during bone and dentine induction have indicated that they may be a good alternative for tissue engineering. Thus, to clarify the influence of the microenvironment on protein and gene expression, MDPC23 cells (mouse dental papilla cell line) and KUSA/A1 cells (bone marrow stromal cell line) were used, both in vitro cell culture and in intra-abdominal diffusion chambers implanted in 4-week-old male immunodefficient mice (SCID mice). Our results indicate that KUSA/A1 cells differentiated into osteoblast-like cells and induced bone tissue inside the chamber, whereas, MDPC-23 showed odontoblast-like characteristics but with a low ability to induce dentin formation. This study shows that MDPC-23 cells are especial cells, which possess morphological and functional characteristics of odontoblast-like cells expressing dentin sialophosphoprotein in vivo. In contrast, dentin sialophosphoprotein gene and protein expression was not detected in both cell lines in vitro. The intra-abdominal diffusion chamber appears as an interesting experimental model for studying phenotypic expression of dental pulp cells in vivo.     

An orientation‐independent DIC microscope allows high resolution imaging of epithelial cell migration and wound healing in a cnidarian model

Epithelial cell dynamics can be difficult to study in intact animals or tissues. Here we use the medusa form of the hydrozoan Clytia hemisphaerica, which is covered with a monolayer of epithelial cells, to test the efficacy of an orientation‐independent differential interference contrast microscope for in vivo imaging of wound healing. Orientation‐independent differential interference contrast provides an unprecedented resolution phase image of epithelial cells closing a wound in a live, nontransgenic animal model. In particular, the orientation‐independent differential interference contrast microscope equipped with a 40x/0.75NA objective lens and using the illumination light with wavelength 546 nm demonstrated a resolution of 460 nm. The repair of individual cells, the adhesion of cells to close a gap, and the concomitant contraction of these cells during closure is clearly visualized.     

KIF15, a key regulator of nasopharyngeal carcinoma development mediated by the P53 pathway

Background: Kinesin family member 15 (KIF15) is a protein that regulates cell mitosis and plays an important role in the development and progression of several types of human cancers. However, the role of KIF15 in the development of nasopharyngeal cancer (NPC) is still unclear. Methods: The differential expression of KIF15 in NPC and para-carcinoma tissues was evaluated based on data collected from Gene Expression Omnibus (GEO) database and immunohistochemical analysis of clinical specimens collected from a patient cohort. Cell lines 5-8F and CNE-2Z were selected for the construction of KIF15‑knockdown cell models. CCK8 assay, flow cytometry, wound healing, Transwell and clone formation assays were used to detect the proliferation, apoptosis, migration, invasion and colony formation of NPC cells in vitro. A mouse xenograft model and the tail intravenous mouse distant transfer model were constructed for in vivo study. Furthermore, the potential molecular mechanisms underlying the effects of KIF15 were explored through western blot analysis, and several in vitro and in vivo functional assays were performed to explore its role in NPC. Results: The results revealed significantly higher expression of KIF15 in NPC tissues compared to para-carcinoma tissues. High levels of KIF15 expression were also associated with short overall survival (OS) and progression-free survival (PFS). Knockdown of the KIF15 gene led to a cell cycle arrest in the growth 2 (G2) phase, inhibition of cell proliferation, migration, invasion, colony formation, and enhanced cell apoptosis. The in vivo murine xenograft experiments showed that down-regulation of the KIF15 gene could inhibit tumor growth and reduce the risk of liver and lung metastasis in NPC. Moreover, the evaluation of the molecular pathway showed that the mitogen-activated protein kinase/P53 pathways might be involved in the KIF15-induced regulation of NPC. Rescue assays indicated that Pifithrin-α could counteract the pro-proliferative and pro-apoptotic effects mediated by KIF15. Conclusion: This work indicated that KIF15 overexpression accelerated the progression of NPC and promoted the development of distant metastases. Therefore, KIF15 may have an important role as a prognostic indicator and a potential drug target for the treatment of NPC.     

Dual-mode reflectance and fluorescence near-video-rate confocal microscope for architectural, morphological and molecular imaging of tissue

We have developed a near‐video‐rate dual‐mode reflectance and fluorescence confocal microscope for the purpose of imaging ex vivo human specimens and in vivo animal models. The dual‐mode confocal microscope (DCM) has light sources at 488, 664 and 784 nm, a frame rate of 15 frames per second, a maximum field of view of 300 × 250 μm and a resolution limit of 0.31 μm laterally and 1.37 μm axially. The DCM can image tissue architecture and cellular morphology, as well as molecular properties of tissue, using reflective and fluorescent molecular‐specific optical contrast agents. Images acquired with the DCM demonstrate that the system has the sub‐cellular resolution needed to visualize the morphological and molecular changes associated with cancer progression and has the capability to image animal models of disease in vivo. In the hamster cheek pouch model of oral carcinogenesis, the DCM was used to image the epithelium and stroma of the cheek pouch; blood flow was visible and areas of dysplasia could be distinguished from normal epithelium using 6% acetic acid contrast. In human oral cavity tissue slices, DCM reflectance images showed an increase in the nuclear‐to‐cytoplasmic ratio and density of nuclei in neoplastic tissues as compared to normal tissue. After labelling tissue slices with fluorescent contrast agents targeting the epidermal growth factor receptor, an increase in epidermal growth factor receptor expression was detected in cancerous tissue as compared to normal tissue. The combination of reflectance and fluorescence imaging in a single system allowed imaging of two different parameters involved in neoplastic progression, providing information about both the morphological and molecular expression changes that occur with cancer progression. The dual‐mode imaging capabilities of the DCM allow investigation of both morphological changes as well as molecular changes that occur in disease processes. Analyzing both factors simultaneously may be advantageous when trying to detect and diagnose disease. The DCM's high resolution and near‐video‐rate image acquisition and the growing inventory of molecular‐specific contrast agents and disease‐specific molecular markers holds significant promise for in vivo studies of disease processes such as carcinogenesis.     

Limited utility of acetoxymethyl (AM)-based intracellular delivery systems, in vivo: interference by extracellular esterases

The use of acetoxymethyl (AM) groups to deliver and trap exogenous optical probes inside cells is an established tool in cell biology/physiology, however, these probes have not been used extensively in vivo. In this study, the use of the acetoxymethyl delivery system for optical probes was evaluated, in vivo. Initial studies revealed very little trapped probe in intact tissues even when near saturating levels of probe were injected in living animals. We tested the hypothesis that extracellular esterases rapidly cleave the acetoxymethyl groups preventing the probes from entering cells, in vivo. The rates of hydrolysis of 11 acetoxymethyl probes in diluted porcine plasma revealed an essentially first order high rate dye cleavage with half times on the order of minutes or less. Studies on mice and rabbits revealed rates 10‐ to 2‐fold higher, respectively. These plasma studies suggested that the acetoxymethyl probes were being cleaved before having a chance to enter cells in tissues in vivo. This was confirmed using intravital 2‐photon excitation microscopy in muscle tissue where several acetoxymethyl probes were found to rapidly cleave in the vascular space during infusion and not be trapped in the muscle cells. Studies with succinimidyl esters that should quickly bind to proteins on cleavage also failed to enter cells, in vivo, consistent with the notion that the cleavage was occurring in the extracellular space. These data suggest that the high level of plasma and extracellular esterase activity render the classical acetoxymethyl probes ineffective for monitoring intracellular events, in vivo. Different approaches to trapping exogenous probes will need to be explored for physiological studies using intravital microscopy.     

A novel whole tooth-in-jaw-bone culture of rat molars: Morphological, immunohistochemical, and laser capture microdissection analysis

In conventional whole‐tooth culture systems, limitation exists regarding maintenance of the vitality of the dental pulp, because this tissue is encased in rigid dentin walls that hinder nutrition supply. We here report a whole tooth‐in‐jaw‐bone culture system of rat mandibular first molars, where transcardiac perfusion with culture medium was carried out before placement of the jaw bone into culture medium, aiming to facilitate longer time preservation of the dental pulp tissue. Following 7 days of culture, the pulp tissues were analyzed by histology and immunohistochemistry to ED2 (antiresident macrophage). ED2‐positive macrophages were also analyzed for their Class II MHC, interleukin‐6 (IL‐6), and p53 mRNA expression levels by means of immune‐laser capture microdissection (immune‐LCM). Dentin sialophosphoprotein (DSPP) mRNA expression in odontobalstic layer was also examined by LCM. Teeth cultured following saline‐perfusion and nonperfusion served as cultured controls. Normal teeth also served as noncultured controls. Histological examination demonstrated that the structure of the pulp tissue was well preserved in the medium‐perfused explants in contrast to the cultured control groups. The Class II MHC, IL‐6, and p53 mRNA expression levels of ED2‐positive cells and DSPP expression levels of odontoblastic layer tissues in the pulp of medium‐perfused explants were not significantly different from those in the noncultured normal teeth. In conclusion, the structural integrity and mRNA expression in the pulp were maintained at the in vivo level in the ex vivo whole tooth‐in‐jaw‐bone culture system. The system may lay the foundation for studies aiming at defining further histological and molecular mechanism of the pulp. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

Reflectance in situ hybridization (RISH): detection,by confocal reflectance laser microscopy,of gold-labelled riboprobes in breast cancer cell lines and histological specimens

A method for reflectance in situ hybridization (RISH) is presented. The importance of the method is demonstrated by results obtained on cytological and histological breast cancer specimens. Scattering reflectance signals from 1-nm colloidal-gold particles after RNA/RNA in situ hybridization, using digoxigenin-labelled riboprobes, were detected by confocal scanning laser microscopy. The mRNA expression of two ras-related genes, rho B and rho C, was analysed in human histological breast cancer specimens and in human breast cancer cell lines. Horizontal (x, y) and vertical (z) optical sections after three-dimensional imaging were used for visualization. A marked heterogeneity (between individual cells and between specimens) was noted for the expression of the rho B gene, both in cytological and in histological samples. On the other hand, rho C was always expressed and showed no heterogeneity. This method allows the identification of several cellular constituents in an heterogeneous tissue structure, as demonstrated by the simultaneous detection of rho B (or rho C) by reflectance and of DNA, cytokeratin and/or vimentin by fluorescence.     

A method for automated detection of gene expression required for the establishment of a digital transcriptome-wide gene expression atlas

Acquiring information about the expression of a gene in different cell populations and tissues can provide key insight into the function of the gene. A high-throughput in situ hybridization (ISH) method was recently developed for rapid and reproducible acquisition of gene expression patterns in serial tissue sections at cellular resolution. Characterizing and analysing expression patterns on thousands of sections requires efficient methods for locating cells and estimating the level of expression in each cell. Such cellular quantification is an essential step in both annotating and quantitatively comparing high-throughput ISH results. Here we describe a novel automated and efficient methodology for performing this quantification on postnatal mouse brain.     

A semiautomated approach for artefact removal in serial tissue cryosections

Thinly sliced serial tissue sections of an organ can be imaged using optical microscopy at a resolution detailing individual cells. When the tissue sections are first subjected to in situ hybridization or immunohistochemistry, these data sets can be analysed for changes in gene expression and gene products. Such spatial information is important for understanding the functional effects of experimental or environmental challenges to the organism. However, a critical step in analysing these data sets is mitigating artefacts that result from the preparation of the tissue sections. In this paper, we describe an automated method with manual validation tools that together enable detecting and addressing artefacts including dust particles and air bubbles.     

Exosomal miR-218 regulates the development of endometritis in dairy cows by targeting TGIF2/TGF-β pathway

Endometritis affects the reproductive capacity of dairy cows and leads to serious economic losses in dairy farming. Clarification of the pathogenesis of endometritis is necessary to improve the reproductive efficiency of dairy cows. Exosomes and their miRNAs have been proven to play an important role in inflammatory regulation. Exosomal miR-218 is a differentially expressed miRNA found in endometrial epithelial cells (EECs) under endometrial inflammation. Therefore, we investigated the expression of miR-218 in the uterine tissue of dairy cows, lipopolysaccharide (LPS) treated EECs, exosomal vesicles, and regulation of exosomal miR-218 by targeting TGIF-2 inducible factor homology frame 2 (TGIF2)/transforming growth factor-beta (TGF-β). The expression of miR-218 was suppressed in inflammatory uterine tissues and LPS treated EECs. The expression of TGIF2 and TGF-β in inflammatory uterine tissues and LPS treated EECs was significantly higher than those in healthy uterine tissues and EECs (p < 0.01). Interestingly, miR-218 derived from donor cells was found to regulate the expression of the target gene TGIF2 in recipient cells through the fusion of exosomes. Concurrently, the expression of its target gene TGIF2 was also suppressed by miR-218 in donor cells resulting in fewer TGIF2 being transported into recipient cells with exosomal fusion. This may be a novel mechanism of miRNAs-mediated regulation and provides a new reference for analyzing the pathogenesis of endometritis in dairy cows.     

Editorial

Automated scanning microphotometry provides an objective assessment of the distribution of metal-bearing (MB) amoebocytes in various tissues of the Pacific oyster, Crassostrea gigas. Silver-staining of these cells in paraffin-embedded sections gave good histochemical enhancement for effective photometric discrimination. Metal-associated pixel fractions (MAPF) for 0.41 mm² tissue-fields were calculated from the results of microphotometric scans, giving an estimate of the metal content and an expression of the population density of MB cells. Gut-associated MB cells in oysters obtained from two geographically-separate metalliferous estuaries had similar distribution patterns, with MAPF values that correlated with metal concentrations in visceral mass determined by atomic absorption spectrophotometry (AAS). The metal content of other tissues varied by two orders of magnitude, the gill having the highest MAPF values. Intermediate MAPF values were found for digestive diverticula and the lowest values in the gonad. There was little difference between gut-associated MB cell populations in oysters from the two collection sites, despite differences in size, glycogen content and gonadal maturation. This non-destructive method of tissue microanalysis may provide a better way of assessing tissue metal-load in individual organisms, and one that is independent of physiological variables.     

Understanding the artefact problem in freeze-fracture replication: a review

Freeze-fracture and freeze-etching techniques do not provide artefact-free images of native in vivo or in vitro cells and tissues. Each preparation stage can produce specific artefacts which must be recognized and understood if these methods are to contribute meaningful information to cell biology. This paper reviews the latest information available on artefacts in freeze-fracture replication (and etching) methods and points to possibilities for avoiding some of them. Different specimens show different sensitivity to artefactual changes and the final images must be interpreted carefully with regard to the multi-event process that has led to their production.     

Receptor autoradiography and 2-deoxyglucose techniques in neuroscience

The use of the receptor autoradiography and 2-deoxyglucose (2-DG) techniques in neuroscience are reviewed. Receptors and other binding sites can be visualized autoradiographically in microtome tissue sections after labelling with radioligand in vivo or in vitro. Autoradiograms are generated by apposition of the labelled tissue to photographic emulsions. Combined with computerized image analysis, this technique can be used to analyse and quantify the microscopic distribution of receptors and receptor alterations associated with lesions or disease in human and animal tissues. The 2-DG technique permits microscopic analysis of modifications in brain glucose utilization induced by physiological and pharmacological manipulations. Limitations of these techniques and attempts to optimize their resolution are also discussed.     

Monitoring of neuronal and glial calcium activity using a novel direct-contact probe

In vivo neuronal and glial calcium activity was monitored using a novel direct‐contact probe that was designed for fluorescence detection deep within biological tissue. A small diameter fibre bundle direct‐contact probe was employed with a laser scanning confocal microscope to detect evoked neuronal and glial activity in the posteromedial barrel subfield of the rat somatosensory cortex in vivo. Resolution of the probe allowed discrimination of single cells, and calcium dynamics spanning milliseconds to several seconds were observed. Initial results indicate that the probe has useful practical applications in the imaging of individual cells and monitoring rapid calcium fluctuations within their cell body and large processes.