Background/Aim
A link between an impaired intestinal barrier, endotoxemia, and the pathogenesis of metabolic diseases, such as type 2 diabetes mellitus (T2DM), has been proposed. In previous work, we ...have demonstrated that the tight junction (TJ)-mediated intestinal barrier in ileum/colon was marginally changed in prediabetic mice; therefore, it does not seem to mainly contribute to the T2DM onset. In this study, the TJ-mediated epithelial barrier in the duodenum and jejunum was evaluated in mice during the development of type 2 prediabetes.
Methods/Results
HF diet induced prediabetes after 60 days associated with a significant rise in intestinal permeability to the small-sized marker Lucifer yellow in these mice, with no histological signs of mucosal inflammation or rupture of the proximal intestine epithelium. As revealed by immunofluorescence, TJ proteins, such as claudins-1, -2, -3, and ZO-1, showed a significant decrease in junctional content in duodenum and jejunum epithelia, already after 15 days of treatment, suggesting a rearrangement of the TJ structure. However, no significant change in total cell content of these proteins was observed in intestinal epithelium homogenates, as assessed by immunoblotting. Despite the changes in intestinal permeability and TJ structure, the prediabetic mice showed similar LPS, zonulin, and TNF-α levels in plasma or adipose tissue, and in intestinal segments as compared to the controls.
Conclusion
Disruption of the TJ-mediated paracellular barrier in the duodenum and jejunum is an early event in prediabetes development, which occurs in the absence of detectable endotoxemia/inflammation and may contribute to the HF diet-induced increase in intestinal permeability.
Pullulan has attracted considerable attention due to its immunogenicity, biodegradability, biocompatibility, and hydrophilic nature, making it useful in cosmetics and pharmaceutical applications. In ...addition, pullulan is considered a biopolymer capable of modification via chemical reactions, which is a promising strategy to expand the range of its applications. In this study, cationic pullulan-based polymers with hydrophilic or amphiphilic nature were successfully synthesized by nucleophilic replacement and ring-opening polymerization. Firstly, pullulan was partially modified with 2-Chloro-N,N-diethylethylamine (DEAE) to generate DEAE-modified pullulan (PULL-DEAE), a polymer with cationic and hydrophilic nature. Secondly, the remaining hydroxyl groups of PULL-DEAE were reacted with N-carbobenzyloxy-l-lysine N-carboxyanhydride (Lys(Z)-NCA), producing the grafted copolymer pullulan-DEAE-g-poly(Z-l-lysine) (PULL-DEAE-g-PZLL), a copolymer with cationic and amphiphilic properties. For the copolymerizations, different monomer concentrations (25, 40, and 55% w/w, relating to pullulan) were used, resulting in three copolymers with different sizes of hydrophobic segments. All polymers were characterized in terms of chemical composition, molar mass, thermal properties, critical aggregation concentration, and cytotoxicity. NMR confirmed the graft copolymerization, and the degree of substitution obtained for each copolymer was 0.13, 0.54, and 0.63, respectively. The results suggest that the physicochemical properties of both pullulan-based cationic derivatives (PULL-DEAE and PULL-DEAE-g-PZLL) could expand the application of modified pullulan for pharmaceutical fields such as drug delivery.
Display omitted
•Chemical modification of PULL to obtain hydrophilic cationic polymer (PULL-DEAE).•Synthesis of amphiphilic copolymer of PULL-DEAE-PZLL with different PZLL amount.•Evaluation of physical and chemical properties by NMR, FTIR, DSC, TGA, and XRD.•Investigation of the hydrophilic and amphiphilic properties by CAC.•Ascertainment of the biocompatibility with cytotoxicity test.
Tissue/cellular actions of butyrate on energy metabolism and intestinal barrier in normal metabolic conditions or prediabetes are still unclear. In this work, we investigated the beneficial effect of ...dietary supplementation with sodium butyrate on energy metabolism, body mass composition, and intestinal epithelial barrier mediated by tight junction (TJ) in chow diet-fed normal and high-fat diet (HF)-fed prediabetic mice, considering the well-known butyrate action as an epigenetic and inflammatory regulator. Butyrate significantly reduced the fat/lean mass ratio, slightly ameliorated dyslipidemia, restored oral glucose tolerance, and increased basal energy expenditure in prediabetic HF-fed mice but had no effect on control animals. Such effects were observed in the absence of significant alterations in the hypothalamic expression of orexigenic and anorexigenic genes and motor activity. Also, butyrate suppressed the whitening effect of HF on brown adipose tissue but did not affect cell bioenergetics in immortalized UCP1-positive adipocytes in vitro. Butyrate reinforced the intestinal epithelial barrier in HF-fed mice and in Caco-2 monolayers, which involved higher trafficking of TJ proteins to the cell-cell contact region of the intestinal epithelia, without affecting TJ gene expression or the acetylation level of histones H3 and H4 in vivo. All metabolic and intestinal effects of butyrate in prediabetic mice occurred in the absence of detectable changes in systemic or local inflammation, or alterations in endotoxemia markers. Butyrate has no effect on chow diet-fed mice but, in the context of HF-induced prediabetes, it prevents metabolic and intestinal dysfunctions independently of its anti-inflammatory and epigenetic actions.
The diet supplementation with sodium butyrate has no metabolic and intestinal effect on chow diet-fed mice but, in the context of high fat (HF) diet-induced prediabetes, it prevents metabolic and intestinal dysfunctions independently of its anti-inflammatory actions. Butyrate reinforces the intestinal epithelial barrier in HF-fed mice and in Caco-2 intestinal cell monolayers exposed to the intestinal luminal content of HF-fed mice treated with butyrate in comparison to those that did not receive this SCFA. The mechanism involves higher trafficking of tight junction (TJ) proteins (such as claudin-1, Cld-1) to the cell-cell contact region of the intestinal epithelium, without affecting TJ gene expression or the acetylation level of histones. Display omitted
The ORF XF2234 in the Xylella fastidiosa genome was identified as encoding a small heat‐shock protein of 17.9 kDa (HSP17.9). HSP17.9 was found as one of the proteins that are induced during X. ...fastidiosa proliferation and infection in citrus culture. Recombinant HSP17.9 was crystallized and surface atomic force microscopy experiments were conducted with the aim of better characterizing the HSP17.9 crystals. X‐ray diffraction data were collected at 2.7 Å resolution. The crystal belonged to space group P4322, with unit‐cell parameters a = 68.90, b = 68.90, c = 72.51 Å, and is the first small heat‐shock protein to crystallize in this space group.
The
Xylella fastidiosa genome program generated a large number of gene sequences that belong to pathogenicity, virulence and adaptation categories from this important plant pathogen. One of these ...genes (XF1729) encodes a protein similar to a superfamily of aldo–keto reductase together with a number of structurally and functionally related NADPH-dependent oxidoreductases. In this work, the similar sequence XF1729 from
X. fastidiosa was cloned onto the pET32Xa/LIC vector in order to overexpress a recombinant His-tag fusion protein in
Escherichia coli BL21(DE3). The expressed protein in the soluble fraction was purified by immobilized metal affinity chromatography (agarose–IDA–Ni resin). Secondary structure contents were verified by circular dichroism spectroscopy. Small angle X-ray scattering (SAXS) measurements furnish general structural parameters and provide a strong indication that the protein has a monomeric form in solution. Also, ab initio calculations show that the protein has some similarities with a previously crystallized aldo–keto reductase protein. The recombinant XF1729 purified to homogeneity catalyzed the reduction of
dl-glyceraldehyde (
K
cat 2.26
s
−1,
K
m 8.20
±
0.98
mM) and 2-nitrobenzaldehyde (
K
cat 11.74
s
−1,
K
m 0.14
±
0.04
mM) in the presence of NADPH. The amino acid sequence deduced from XF1729 showed the highest identity (40% or higher) with several functional unknown proteins. Among the identified AKRs, we found approximately 29% of identity with YakC (AKR13), 30 and 28% with AKR11A and AKR11B, respectively. The results establish XF1729 as the new member of AKR family, AKR13B1. Finally, the first characterization by gel filtration chromatography assays indicates that the protein has an elongated shape, which generates an apparent higher molecular weight. The study of this protein is an effort to fight
X. fastidiosa, which causes tremendous losses in many economically important plants.
In the search of new photoactive species that may be of use either in energy conversion or in photodynamic therapy, we studied the functionalization of silicon (10 0) with thionin using the ...glutaraldehyde coupling reaction. Surface properties were obtained by ellipsometric measurements, atomic force microscopy, and luminescence spectroscopy, which indicated the formation of a well organised monolayer in the silicon surface. In addition, the comparison of Raman spectroscopy data with first-principles pseudopotential calculations of the vibrational modes of the thionin molecule also indicate the formation of a monolayer of intact thionin molecules. Therefore, the simple functionalization process (involving only mild aqueous solution chemistry) described here works well and can be used to construct smooth monolayers of photoactive molecules with functional amine groups.
The small heat shock proteins (smHSPs) belong to a family of proteins that function as molecular chaperones by preventing protein aggregation and are also known to contain a conserved region termed ...α-crystallin domain. Here, we report the expression, purification, and partial characterization of a novel smHSP (HSP17.9) from the phytopathogen
Xylella fastidiosa, causal agent of the citrus variegated chlorosis (CVC). The gene was cloned into a pET32-Xa/LIC vector to over-express the protein coupled with fusion tags in
Escherichia coli BL21(DE3). The expressed HSP17.9 was purified by immobilized metal affinity chromatography (IMAC) and had its identity determined by mass spectrometry (MALDI-TOF). The correct folding of the purified recombinant protein was verified by circular dichroism spectroscopy. Finally, the HSP17.9 protein also proved to efficiently prevent induced aggregation of insulin, strongly indicating a chaperone-like activity.
Abstract Context Transcatheter ablation of atrial fibrillation (AF) has undergone important development, with acceptable midterm results in terms of the safety and recurrence. A meta-analysis was ...performed to identify the periprocedural complications, midterm success rates and predictors of recurrence after AF ablation. Methods and results 4357 patients with paroxysmal AF, 1083 with persistent AF and 1777 with long standing AF were included. The pooled analysis showed that there was an in-hospital complication rate of tamponade requiring drainage of 0.99% (0.44–1.54; CI 99%), stroke with neurological persistent impairment of 0.22% (0.04–0.47; CI 99%), and stroke without of 0.36% (0.03–0.70; CI 99%) After a follow up of 22 (13–28) months and 1.23 (1.19–1.5; CI 99%) procedures per patient, the AF recurrence rate was 31.20% (24.87–34.81; CI 99%). The persistent AF patients exhibited a greater risk of recurrence after the first ablation (OR 1.78 1.14, 2.77 CI 99%), but a trend towards non significance was present in the patients with more than one procedure (OR 1.69 0.95, 3.00 CI 99%). The most powerful predictors of an AF ablation failure in the overall population were a recurrence within 30-days (OR 4.30; 2.00–10.80), valvular AF (OR 5.20; 2.22–9.50) and a left atrium diameter of more than 50 mm (OR 5.10 2.00–12.90; all CI 95%). Conclusions Persistent AF remains burdened from higher recurrence rates, however not so following redo-procedures. Three predictors, valvular AF, a left atrium diameter longer than 50 mm and recurrence within 30 days, could be appraised to drive selection of patients and therapeutic strategy.
One hundred fifty-nine extracted single-rooted maxillary human teeth were instrumented and randomly divided into nine groups of 17 teeth each and 6 control teeth. Experimental groups were obturated ...with Thermafil, Obtura II, Ultrafil Regular Set gutta-percha, and Ultrafil Firm Set gutta-percha, each with or without root canal sealer. A control group was obturated using the lateral condensation technique and sealer. Teeth were immersed in a resorcinol-formaldehyde resin for 5 days at 4°C, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5, 2.5, and 3.5 mm from the anatomical apex, and examined under a stereomicroscope at ×25 magnification. The resin filled the spaces in the gap between the canal wall and the gutta-percha and this was measured at each of the three levels. The ratio of the area of the resin to the total area of the canal was obtained as the mean leakage area. The results showed no significant difference in the mean leakage area at the same level for the different obturation materials. However, the leakage was significantly less for all materials when root canal sealer was used.
PDF
