Growth of bifidobacteria and clostridia on human and cow milk saccharides

For healthy infants, which were born normally and fully breastfed, the dominant component of the intestinal microflora are bifidobacteria. However, infants born by caesarean section possess clostridia as a dominant intestinal bacterial group. The aim of the present study was to determine whether bifidobacteria and clostridia are able to grow on human milk oligosaccharides (HMOs) and other carbon sources - lactose, cow milk (CM) and human milk (HM). Both bifidobacteria and clostridia grew on lactose and in CM. Bifidobacteria grew in HM and on HMOs. In contrast, 3 out of 5 strains of clostridia were not able to grow in HM. No clostridial strain was able to utilise HMOs. While both bifidobacterial strains were resistant to lysozyme, 4 out of 5 strains of clostridia were lysozyme-susceptible. It seems that HMOs together with lysozyme may act as prebiotic-bifidogenic compounds inhibiting intestinal clostridia.     

Syndecan-4 associates with alpha-actinin

Cell adhesion to the extracellular matrix influences many cellular functions. The integrin family of matrix receptors plays major roles in the formation of adhesions, but other proteins modulate integrin signaling. Syndecan-4, a transmembrane proteoglycan, cooperatively signals with integrins during the formation of focal adhesions. To date, a direct link between syndecan-4 and the cytoskeleton has remained elusive. We now demonstrate by Triton X-100 extraction immunoprecipitation and in vitro binding assays that the focal adhesion component alpha-actinin interacts with syndecan-4 in a beta-integrin-independent manner.     

Exploring the oxidation and iron binding profile of a cyclodextrin encapsulated quercetin complex unveiled a controlled complex dissociation through a chemical stimulus

Background

Flavonoids possess a rich polypharmacological profile and their biological role is linked to their oxidation state protecting DNA from oxidative stress damage. However, their bioavailability is hampered due to their poor aqueous solubility. This can be surpassed through encapsulation to supramolecular carriers as cyclodextrin (CD). A quercetin- 2HP-β-CD complex has been formerly reported by us. However, once the flavonoid is in its 2HP-β-CD encapsulated state its oxidation potential, its decomplexation mechanism, its potential to protect DNA damage from oxidative stress remained elusive. To unveil this, an array of biophysical techniques was used.

Epigenetic silencing of miR-26A1 in chronic lymphocytic leukemia and mantle cell lymphoma: Impact on EZH2 expression

Downregulation of miR26A1 has been reported in various B-cell malignancies; however, the mechanism behind its deregulation remains largely unknown. We investigated miR26A1 methylation and expression levels in a well-characterized series of chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). From 450K methylation arrays, we first observed miR26A1 (cg26054057) as uniformly hypermethylated in MCL (n = 24) (all >75%), while CLL (n = 18) showed differential methylation between prognostic subgroups. Extended analysis using pyrosequencing confirmed our findings and real-time quantitative PCR verified low miR26A1 expression in both CLL (n = 70) and MCL (n = 38) compared to normal B-cells. Notably, the level of miR26A1 methylation predicted outcome in CLL, with higher levels seen in poor-prognostic, IGHV-unmutated CLL. Since EZH2 was recently reported as a target for miR26A1, we analyzed the expression levels of both miR26A1 and EZH2 in primary CLL samples and observed an inverse correlation. By overexpression of miR26A1 in CLL and MCL cell lines, reduced EZH2 protein levels were observed using both Western blot and flow cytometry. In contrast, methyl-inhibitor treatment led to upregulated miR26A1 expression with a parallel decrease of EZH2 expression. Finally, increased levels of apoptosis were observed in miR26A1-overexpressing cell lines, further underscoring the functional relevance of miR26A1. In summary, we propose that epigenetic silencing of miR26A1 is required for the maintenance of increased levels of EZH2, which in turn translate into a worse outcome, as shown in CLL, highlighting miR26A1 as a tumor suppressor miRNA.     

The preventive and therapeutic effects of molecular hydrogen in ocular diseases and injuries where oxidative stress is involved

Oxidative stress initiates, accompanies and contributes to the development of several human diseases and injuries, including ocular diseases. Reactive oxygen species (ROS) can generate oxidative stress via excessive ROS production and/or decreased physiologically occurring antioxidants. To replace these weakened antioxidants, substances with effective antioxidant properties are needed in order to suppress oxidative stress and enable healing. Molecular hydrogen (H₂) is very suitable for this purpose due to its unique properties. H₂ is the only antioxidant that crosses the blood–brain and blood-ocular barriers. It quickly penetrates through tissue due to its small molecular size and effectively removes ROS, mainly hydroxyl radicals and peroxynitrite. Apart from its antioxidant effects, H₂ also displays anti-inflammatory, antiapoptotic, cytoprotective and mitohormetic properties. A significant advantage of H₂ is its nontoxicity, even when applied at high concentrations. In this review, we present the results of studies utilising H₂ in the treatment of ocular diseases involving oxidative stress. These results, obtained in experimental animals as well as in human clinical studies, show that the suppression of oxidative stress by H₂ treatment leads to the prevention or improvement of ocular diseases. In severe degenerative diseases, H₂ slows disease progression.     

Transgenic mouse model expressing tdTomato under involucrin promoter as a tool for analysis of epidermal differentiation and wound healing

The epidermis is a stratified tissue composed of different keratinocyte layers that create a barrier protecting the body from external influences, pathogens, and dehydration. The barrier function is mainly achieved by its outermost layer, the stratum corneum. To create a mouse model to study pathophysiological processes in the outermost layers of the epidermis in vivo and in vitro we prepared a construct containing red fluorescent td-Tomato reporter sequence under the control of involucrin promoter and its first intron. Transgenic mice were generated by pronuclear injection and the expression and regulation of the transgene was determined by in vivo imaging and fluorescent microscopy. The promoter targeted the transgene efficiently and specifically into the outermost epidermal layers although weak expression was also found in epithelia of tongue and bladder. The regulation of expression in the epidermis, i.e. fluorescence intensity of the reporter, could be easily followed during wound healing and dermatitis. Thus, these transgenic mice carrying the tdTomato reporter could be used as a valuable tool to study impact of various genes dysregulating the epidermal barrier and to follow effects of therapeutic agents for treatment of skin diseases in vivo.     

Cellular retinol binding protein 1 modulates photoreceptor outer segment folding in the isolated eye

In a previous study, we used differential proteomics to identify retinal proteins whose steady‐state levels were altered in an experimental system in which photoreceptor outer segments were improperly folded. We determined that the steady‐state level of cellular retinol binding protein 1 (CRBP1) was downregulated in eyes lacking organized outer segments. The purpose of this study was to determine if CRBP1 is a plausible candidate for regulating outer segment assembly. We used Morpholinos to directly test the hypothesis that a decreased level of CRBP1 protein was associated with the misfolding of outer segments. Results from these studies indicate that downregulation of CRBP1 protein resulted in aberrant assembly of outer segments. Because CRBP1 plays a dual role in the retina—retinal recycling and generation of retinoic acid—we evaluated both possibilities. Our data demonstrate that outer segment folding was not modified by 11‐cis retinal supplementation, suggesting that CRBP1 influences outer segment assembly through a mechanism unrelated to rhodopsin regeneration. In contrast, retinoic acid is required for the proper organization of nascent outer segment membranes. The localization of CRBP1 within Muller cells and the RPE and its demonstrated role in modulating the proper folding of nascent outer segment membranes through retinoic acid further elucidates the role of these cells in directly influencing photoreceptor physiology. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 623–635, 2010