Abstract Objectives Contemporary adhesives lose their bond strength to dentin regardless of the bonding system used. This loss relates to the hydrolysis of collagen matrix of the hybrid layers. The ...preservation of the collagen matrix integrity is a key issue in the attempts to improve the dentin bonding durability. Methods Dentin contains collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins, which are responsible for the hydrolytic degradation of collagen matrix in the bonded interface. Results The identities, roles and function of collagenolytic enzymes in mineralized dentin has been gathered only within last 15 years, but they have already been demonstrated to have an important role in dental hard tissue pathologies, including the degradation of the hybrid layer. Identifying responsible enzymes facilitates the development of new, more efficient methods to improve the stability of dentin–adhesive bond and durability of bond strength. Significance Understanding the nature and role of proteolytic degradation of dentin–adhesive interfaces has improved immensely and has practically grown to a scientific field of its own within only 10 years, holding excellent promise that stable resin–dentin bonds will be routinely available in a daily clinical setting already in a near future.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract Objective Endogenous dentin collagenolytic enzymes, matrix metalloproteinases (MMPs) and cysteine cathepsins, are responsible for the time-dependent hydrolysis of collagen matrix of hybrid ...layers. As collagen matrix integrity is essential for the preservation of long-term dentin bond strength, inhibition of endogenous dentin proteases is necessary for durable resin-bonded restorations. Methods Several tentative approaches to prevent enzyme function have been proposed. Some of them have already demonstrated clinical efficacy, while others need to be researched further before clinical protocols can be proposed. This review will examine both the principles and outcomes of techniques to prevent collagen hydrolysis in dentin–resin interfaces. Results Chlorhexidine, a general inhibitor of MMPs and cysteine cathepsins, is the most tested method. In general, these experiments have shown that enzyme inhibition is a promising approach to improve hybrid layer preservation and bond strength durability. Other enzyme inhibitors, e.g. enzyme-inhibiting monomers, may be considered promising alternatives that would allow more simple clinical application than chlorhexidine. Cross-linking collagen and/or dentin matrix-bound enzymes could render hybrid layer organic matrices resistant to degradation. Alternatively, complete removal of water from the hybrid layer with ethanol wet bonding or biomimetic remineralization should eliminate hydrolysis of both collagen and resin components. Significance Understanding the function of the enzymes responsible for the hydrolysis of hybrid layer collagen has prompted several innovative approaches to retain hybrid layer integrity and strong dentin bonding. The ultimate goal, prevention of collagen matrix degradation with clinically applicable techniques and commercially available materials may be achievable in several ways.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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Cancer is recognized as the major cause of death worldwide and the most challenging public health issues. Tumor cells exhibit molecular adaptations and metabolic reprograming to ...sustain their high proliferative rate and autophagy plays a pivotal role to supply the high demand for metabolic substrates and for recycling cellular components, which has attracted the attention of the researchers. The modulation of the autophagic process sensitizes tumor cells to chemotherapy-induced cell death and reverts drug resistance. In this regard, many in vitro and in vivo studies having shown the anticancer activity of phenothiazine (PTZ) derivatives due to their potent cytotoxicity in tumor cells. Interestingly, PTZ have been used as antiemetics in antitumor chemotherapy-induced vomiting, maybe exerting a combined antitumor effect. Among the mechanisms of cytotoxicity, the modulation of autophagy by these drugs has been highlighted. Therefore, the use of PTZ derivatives can be considered as a repurposing strategy in antitumor chemotherapy. Here, we provided an overview of the effects of antipsychotic PTZ on autophagy in tumor cells, evidencing the molecular targets and discussing the underlying mechanisms. The modulation of autophagy by PTZ in tumor cells have been consistently related to their cytotoxic action. These effects depend on the derivative, their concentration, and also the type of cancer. Most data have shown the impairment of autophagic flux by PTZ, probably due to the blockade of lysosome-autophagosome fusion, but some studies have also suggested the induction of autophagy. These data highlight the therapeutic potential of targeting autophagy by PTZ in cancer chemotherapy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background: The disease caused by hepatitis C virus (HCV) is asymptomatic, silent, and progressive liver disease. In HCV-infected patients the increase in serum HA is associated with the development ...of hepatic fibrosis and disease progression. Methods: HCV-RNA detection was performed in all serological samples of blood donors that tested positive using HCV Ultra ELISA. Determination of hyaluronan (HA) was performed in positive HCV samples using ELISA-like fluorometric method. The HA content was compared to HCV viral load, genotype of the virus, liver fibrosis as well as ALT and GGT liver biomarkers. Results: Persistently normal ALT (<40 U/L) and GGT (<50 U/L) serum levels were detected in 75% and 69% of the HCV-Infected blood donors, respectively. Based on ROC analysis, the HA value < 34.2 ng/mL is an optimal cut-off point to exclude HCV viremia (specificity = 91%, NPV = 99%). Applying HA value ≥34.2 ng/mL significant liver fibrosis (≥F2) can be estimated in 46% of the HCV-infected blood donors. HA serum level (≥34.2 ng/mL) associated with a high ALT level (>40 U/mL) can correctly identify HCV infection and probable liver fibrosis (sensitivity = 96% and specificity = 90%) in asymptomatic blood donors. Conclusions: A high level of HA (≥34.2 ng/mL) in association with ALT (≥40 U/L) in serum can provide a good clinical opportunity to detect HCV-infected asymptomatic persons that potentially require a liver biopsy confirmation and antiviral treatment to prevent the development of advanced liver fibrosis or cirrhosis.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Evaluate molecularly the role of P11-4 self-assembly peptide in dentin remineralization and its interaction with collagen I. Methods: The calcium-responsive P11-4 peptide was analyzed by intrinsic ...fluorescence emission spectrum, circular dichroism spectrum (CD), and atomic force microscope (AFM). Differential light scattering was used to monitor the nucleation growth rate of calcium phosphate nanocrystals in the absence or in the presence of P11-4. AFM was used to analyze the radial size (nm) of calcium phosphate nanocrystals formed in the absence or in the presence of P11-4, as well as to verify the spatial structure of P11-4 in the absence or in the presence of Ca2+. Results: The interaction of Ca2+ with the P11-4 (KD = 0.58 ± 0.06 mM) promotes the formation of β-sheet antiparallel structure, leads to its precipitation in saturated solutions of Ca/P = 1.67 and induces the formation of parallel large fibrils (0.6 – 1.5 µm). P11-4 organized the HAP nucleation by reducing both the growth rate and size variability of nanocrystals, analyzed by the F test (p < 0.0001, N = 30). P11-4 interacts (KD = 0.75 ± 0.06 μM) with the KGHRGFSGL motif present at the C-terminal collagen telopeptide domain. P11-4 also increased the amount of HAP and collagen in the MDPC-23 cells. Significance: The presented data propose a mechanism that will help future clinical and/or basic research to better understand a molecule able to inhibit structural collagen loss and help the impaired tissue to remineralize.
•P11-4 is a self-assembled peptide that can form β-sheets when exposed to physiological stimuli.•P11-4 modulates the ACP in the OCP and the rate of the OCP conversion to HAP.•P11-4 binds at the KGHRGFSGL collagen I domain.•P11-4 can induce and guide hydroxyapatite mineralization in MDPC-23 odontoblast-like cell model.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Relapse and drug resistance is still major challenges in the treatment of leukemia. Promethazine, an antihistaminic phenothiazine derivative, has been used to prevent chemotherapy-induced emesis, ...although there is no report about its antitumor potential. Thus, we evaluated the promethazine cytotoxicity against several leukemia cells and the underlying mechanisms were investigated. Promethazine exhibited potent and selective cytotoxicity against all leukemia cell types in vitro at clinically relevant concentrations. Philadelphia positive chronic myeloid leukemia (CML) K562 cells were the most sensitive cell line. The cytotoxicity of promethazine in these cells was triggered by the activation of AMPK and inhibition of PI3K/AKT/mTOR pathway. The subsequent downstream effects were NOXA increase, MCL-1 decrease, and Beclin-1 activation, resulting in autophagy-associated apoptosis. These data highlight targeting autophagy may represent an interesting strategy in CML therapy, and also the antitumor potential of promethazine by acting in AMPK and PI3K/AKT/mTOR signaling pathways. Since this drug is currently used with relative low side effects, its repurposing may represent a new therapeutic opportunity for leukemia treatment.
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•Resistance to chemotherapy is a clinical challenge in leukemia therapy.•Antiallergic small molecule promethazine is used as antiemetic in cancer patients.•Promethazine induced a selective leukemia cell death through autophagy-apoptosis.•For the first time, the antitumor effects of promethazine were described.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Human plasma kallikrein-kinin system proteins are related to inflammation through bradykinin. In the proximity of its target cells, high molecular weight kininogen (H-kininogen) is the substrate of ...plasma kallikrein, which releases bradykinin from H-kininogen. Heparan sulfate proteoglycans (HSPGs) play a critical role in either recruiting kinin precursors from the plasma, or in the assembly of kallikrein-kinin system components on the cell surface. Furthermore, HSPGs mediate the endocytosis and activation of H-kininogen and plasma prekallikrein. In the presence of HSPGs (Chinese hamster ovary cell, CHO-K1, wild type cells) both heparin and heparan sulfate strongly inhibit the H-kininogen interaction with the cell membrane. H-kininogen is internalized in endosomal acidic vesicles in CHO-K1 but not in CHO-745 cells (mutant cells deficient in glycosaminoglycan biosynthesis). The endocytosis process is lipid raft-mediated and is dependent on caveolae. Both types of CHO cells do not internalize bradykinin-free H-kininogen. At pH 7.35, bradykinin is released from H-kininogen on the surface of CHO-745 cells only by serine proteases; however, in CHO-K1 cells either serine or cysteine proteases are found to be involved. The CHO-K1 cell lysate contains different kininogenases. Plasma prekallikrein endocytosis in CHO-K1 cells is independent of H-kininogen, and also prekallikrein is not internalized by CHO-745 cells. Plasma prekallikrein cleavage/activation is independent of glycosaminoglycans but plasma kallikrein formation is more specific on H-kininogen assembled on the cell surface through glycosaminoglycans. In this mini-review, the importance of HSPGs in the regulation of plasma kallikrein-kinin system proteins is shown.
Ischemia and reperfusion (I/R) causes tissue damage and intracellular calcium levels are a factor of cell death. Sodium calcium exchanger (NCX) regulates calcium extrusion and Trisulfated ...Disaccharide (TD) acts on NCX decreasing intracellular calcium through the inhibition of the exchange inhibitory peptide (XIP).
The aims of this research are to evaluate TD effects in liver injury secondary to I/R in animals and in vitro action on cytosolic calcium of hepatocytes cultures under calcium overload.
Wistar rats submitted to partial liver ischemia were divided in groups:
(n = 10): surgical manipulation with no liver ischemia; Saline: (n = 15): rats receiving IV saline before reperfusion; and TD: (n = 15): rats receiving IV TD before reperfusion. Four hours after reperfusion, serum levels of AST, ALT, TNF-α, IL-6, and IL-10 were measured. Liver tissue samples were collected for mitochondrial function and malondialdehyde (MDA) content. Pulmonary vascular permeability and histologic parameters of liver were determined. TD effect on cytosolic calcium was evaluated in BRL3A hepatic rat cell cultures stimulated by thapsigargin pre and after treatment with TD.
AST, ALT, cytokines, liver MDA, mitochondrial dysfunction and hepatic histologic injury scores were less in TD group when compared to Saline Group (p<0.05) with no differences in pulmonary vascular permeability. In culture cells, TD diminished the intracellular calcium raise and prevented the calcium increase pre and after treatment with thapsigargin, respectively.
TD decreases liver cell damage, preserves mitochondrial function and increases hepatic tolerance to I/R injury by calcium extrusion in Ca2+ overload situations.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cells undergoing hypoxia experience intense cytoplasmic calcium (Ca
2+
) overload. High concentrations of intracellular calcium (Ca
2+
i
) can trigger cell death in the neural tissue, a hallmark of ...stroke. Neural Ca
2+
homeostasis involves regulation by the Na
+
/Ca
2+
exchanger (NCX). Previous data published by our group showed that a product of the enzymatic depolymerization of heparin by heparinase, the unsaturated trisulfated disaccharide (TD; ΔU, 2S-GlcNS, 6S), can accelerate Na
+
/Ca
2+
exchange via NCX, in hepatocytes and aorta vascular smooth muscle cells. Thus, the objective of this work was to verify whether TD could act as a neuroprotective agent able to prevent neuronal cell death by reducing Ca
2+
i
. Pretreatment of N2a cells with TD reduced Ca
2+
i
rise induced by thapsigargin and increased cell viability under Ca
2+
I
overload conditions and in hypoxia. Using a murine model of stroke, we observed that pretreatment with TD decreased cerebral infarct volume and cell death. However, when mice received KB-R7943, an NCX blocker, the neuroprotective effect of TD was abolished, strongly suggesting that this neuroprotection requires a functional NCX to happen. Thus, we propose TD-NCX as a new therapeutic axis for the prevention of neuronal death induced by Ca
2+
i
overload.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The tissue engineering of dental oral tissue is tackling significant advances and the use of stem cells promises to boost the therapeutical approaches of regenerative dentistry. Despite advances in ...this field, the literature is still scarce regarding the modulatory effect of laser photobiomodulation (PBM) on genes related to inflammation and osteogenesis in Postnatal Human Dental Pulp Stem cells (DPSCs). This study pointedly investigated the effect of PBM treatment in proliferation, growth and differentiation factors, mineralization, and extracellular matrix remodeling genes in DPSCs. Freshly extracted human third molars were used as a source for DPSCs isolation. The isolated DPSCs were stimulated to an inflammatory state, using a lipopolysaccharide (LPS) model, and then subjected or not to laser PBM. Each experiment was statistically evaluated according to the sample distribution. A total of 85 genes related to inflammation and osteogenesis were evaluated regarding their expression by RT-PCR. Laser PBM therapy has shown to modulate several genes expression in DPSCs. PBM suppressed the expression of inflammatory gene TNF and RANKL and downregulated the gene expression for VDR and proteolytic enzymes cathepsin K, MMP-8 and MMP-9. Modulation of gene expression for proteinase-activated receptors (PARs) following PBM varied among different PARs. As expected, PBM blocked the odontoblastic differentiation of DPSCs when subjected to LPS model. Conversely, PBM has preserved the odontogenic potential of DPSCs by increasing the expression of TWIST-1/RUNEX-2/ALP signaling axis. PBM therapy notably played a role in the DPSCs genes expression that mediate inflammation process and tissue mineralization. The present data opens a new perspective for PBM therapy in mineralized dental tissue physiology.
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