Παρασκευή, 28 Ιουνίου 2019

Biomedicines, Vol. 7, Pages 46: Protein Nanotubes: From Bionanotech towards Medical Applications
Nanobiotechnology involves the study of structures found in nature to construct nanodevices for biological and medical applications with the ultimate goal of commercialization. Within a cell most biochemical processes are driven by proteins and associated macromolecular complexes. Evolution has optimized these protein-based nanosystems within living organisms over millions of years. Among these are flagellin and pilin-based systems from bacteria, viral-based capsids, and eukaryotic microtubules and amyloids. While carbon nanotubes (CNTs), and protein/peptide-CNT composites, remain one of the most researched nanosystems due to their electrical and mechanical properties, there are many concerns regarding CNT toxicity and biodegradability. Therefore, proteins have emerged as useful biotemplates for nanomaterials due to their assembly under physiologically relevant conditions and ease of manipulation via protein engineering. This review aims to highlight some of the current research employing protein nanotubes (PNTs) for the development of molecular imaging biosensors, conducting wires for microelectronics, fuel cells, and drug delivery systems. The translational potential of PNTs is highlighted.
Biomedicines, Vol. 7, Pages 45: Evidence for Contamination of Silica Microparticles in Advanced Platelet-Rich Fibrin Matrices Prepared Using Silica-Coated Plastic Tubes
Platelet-rich fibrin (PRF) therapy has been widely applied in regenerative dentistry, and PRF preparation has been optimized to efficiently form fibrin clots using plain glass tubes. Currently, a shortage of commercially available glass tubes has forced PRF users to utilize silica-coated plastic tubes. However, most plastic tubes are approved by regulatory authorities only for diagnostic use and remain to be approved for PRF therapy. To clarify this issue, we quantified silica microparticles incorporated into the PRF matrix. Blood samples were collected into three different brands of silica-containing plastic tubes and were immediately centrifuged following the protocol for advanced-PRF (A-PRF). Advanced-PRF-like matrices were examined using a scanning electron microscope (SEM), and silica microparticles were quantified using a spectrophotometer. Each brand used silica microparticles of specific size and appearance. Regardless of tube brands and individual donors, significant, but not accidental, levels of silica microparticles were found to be incorporated into the A-PRF-like matrix, which will be consequently incorporated into the implantation sites. Presently, from the increasing data for cytotoxicity of amorphous silica, we cannot exclude the possibility that such A-PRF-like matrices negatively influence tissue regeneration through induction of inflammation. Further investigation should be performed to clarify such potential risks.
Biomedicines, Vol. 7, Pages 44: The Role of Wnt and R-spondin in the Stomach During Health and Disease
The Wnt signaling pathway is one of the most prominent developmental signals. In addition to its functions in development, there is emerging evidence that it is also crucial for various organ functions in adult organisms, where Wnt signaling controls tissue stem cell behavior, proliferation and differentiation. Deregulation of Wnt signaling is involved in various pathological conditions and has been linked to malignant tissue transformation in different organ systems. The study of the Wnt signaling pathway has revealed a complex regulatory network that tightly balances the quality and strength of Wnt signaling in tissues. In this context, R-spondins are secreted proteins that stabilize Wnt receptors and enhance Wnt signaling. In this review we focus on new insights into the regulatory function of Wnt and R-spondin signaling in the stomach. In addition to its function in the healthy state, we highlight the connection between Wnt signaling and infection with Helicobacter pylori (H. pylori), a pathogen that colonizes the stomach and is the main risk factor for gastric cancer. In addition to experimental data that link Wnt signaling to carcinogenesis, we discuss that Wnt signaling is affected in a substantial proportion of patients with gastric cancer, and provide examples for potential clinical implications for altered Wnt signaling in gastric cancer.
Biomedicines, Vol. 7, Pages 43: Periodontitis Stage III–IV, Grade C and Correlated Factors: A Histomorphometric Study
Background: Periodontitis is a disease that leads to serious functional and esthetic dysfunctions. Periodontitis exists in different forms, and its etiology is related to multiple component causes. Two key processes involved in the evolution of this pathology are angiogenesis and inflammatory infiltrate. The aim of this study was to understand if important factors such as smoking, gender, age, plaque, pus, and probing pocket depth could influence the histomorphological pattern of generalized stage III–IV, grade C periodontitis (GPIII–IVC), which is a particular form of periodontitis. Methods: Eighteen subjects with GPIII–IVC were enrolled in this study. The percentage of inflammatory cells and the vascular area were measured and evaluated in relation to each periodontal disease-associated factor. Results: Females showed a significant increase in the percentage of inflammatory cells compared to males (6.29% vs. 2.28%, p-value = 0.020) and it was higher in non-smokers than in smokers (4.56% vs. 3.14%, p-value = 0.048). Young patients showed a significant increase in vascular area percentage compared to older patients (0.60% vs. 0.46%, p-value = 0.0006) and this percentage was also higher in non-smokers compared to smokers (0.41% vs. 0.55%, p-value = 0.0008). The vascular area was also more than halved in subjects with residual plaque on tooth surfaces (0.74% vs. 0.36%, p-value = 0.0005). Conclusions: These results suggested that even if these factors are commonly related to the worsening of periodontal status, some of them (pus and periodontal probing depth (PPD)) do not affect the inflammatory and vascular patterns.
Biomedicines, Vol. 7, Pages 42: Neuromyelitis Optica Spectrum Disorder and Anti-MOG Syndromes
Neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein (anti-MOG) syndromes are immune-mediated inflammatory conditions of the central nervous system that frequently involve the optic nerves and the spinal cord. Because of their similar clinical manifestations and habitual relapsing course they are frequently confounded with multiple sclerosis (MS). Early and accurate diagnosis of these distinct conditions is relevant as they have different treatments. Some agents used for MS treatment may be deleterious to NMOSD. NMOSD is frequently associated with antibodies which target aquaporin-4 (AQP4), the most abundant water channel in the CNS, located in the astrocytic processes at the blood-brain barrier (BBB). On the other hand, anti-MOG syndromes result from damage to myelin oligodendrocyte glycoprotein (MOG), expressed on surfaces of oligodendrocytes and myelin sheaths. Acute transverse myelitis with longitudinally extensive lesion on spinal MRI is the most frequent inaugural manifestation of NMOSD, usually followed by optic neuritis. Other core clinical characteristics include area postrema syndrome, brainstem, diencephalic and cerebral symptoms that may be associated with typical MRI abnormalities. Acute disseminated encephalomyelitis and bilateral or recurrent optic neuritis are the most frequent anti-MOG syndromes in children and adults, respectively. Attacks are usually treated with steroids, and relapses prevention with immunosuppressive drugs. Promising emerging therapies for NMOSD include monoclonal antibodies and tolerization.
Biomedicines, Vol. 7, Pages 41: Reporter Cell Assessment of TLR4-Induced NF-κB Responses to Cell-Free Hemoglobin and the Influence of Biliverdin
Hemoglobin (Hb) released during red blood cell lysis can initiate TLR4-dependent signaling and trigger NF-κB activation in surrounding cells. Observations of chronic bleeding in various cancers leads us to hypothesize that Hb and Hb degradation products released from lysed RBC near cancer nests might modulate local TLR4-positive cells. We addressed the hypothesis in vitro by measuring Hb- and biliverdin (Bv)-induced NF-κB signaling in an engineered human TLR4 reporter cell model (HEK-BlueTM hTLR4). Therein, TLR4 stimulation was assessed by measuring NF-κB-dependent secreted alkaline phosphatase (SEAP). hTLR4 reporter cells incubated with 8 ηM lipopolysaccharide (LPS) or 20-40 μM fungal mannoprotein (FM) produced significant amounts of SEAP. hTLR4 reporter cells also produced SEAP in response to human, but not porcine or bovine, Hb. HEK-Blue Null2TM reporter cells lacking TLR4 did not respond to LPS, FM, or Hb. Bv was non-stimulatory in reporter cells. When Bv was added to Hb-stimulated reporter cells, SEAP production was reduced by 95%, but when Bv was applied during LPS and FM stimulation, SEAP production was reduced by 33% and 27%, respectively. In conclusion, Hb initiated NF-κB signaling that was dependent upon TLR4 expression and that Bv can act as a TLR4 antagonist. Moreover, this study suggests that hemorrhage and extravascular hemolysis could provide competitive Hb and Bv signaling to nearby cells expressing TLR4, and that this process could modulate NF-κB signaling in TLR4-positive cancer cells and cancer-infiltrating leukocytes.
Biomedicines, Vol. 7, Pages 40: Controlling Nuclear NF-κB Dynamics by β-TrCP—Insights from a Computational Model
The canonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway regulates central processes in mammalian cells and plays a fundamental role in the regulation of inflammation and immunity. Aberrant regulation of the activation of the transcription factor NF-κB is associated with severe diseases such as inflammatory bowel disease and arthritis. In the canonical pathway, the inhibitor IκB suppresses NF-κB’s transcriptional activity. NF-κB becomes active upon the degradation of IκB, a process that is, in turn, regulated by the β-transducin repeat-containing protein (β-TrCP). β-TrCP has therefore been proposed as a promising pharmacological target in the development of novel therapeutic approaches to control NF-κB’s activity in diseases. This study explores the extent to which β-TrCP affects the dynamics of nuclear NF-κB using a computational model of canonical NF-κB signaling. The analysis predicts that β-TrCP influences the steady-state concentration of nuclear NF-κB, as well as changes characteristic dynamic properties of nuclear NF-κB, such as fold-change and the duration of its response to pathway stimulation. The results suggest that the modulation of β-TrCP has a high potential to regulate the transcriptional activity of NF-κB.
Biomedicines, Vol. 7, Pages 39: Differential Expression of CD3, TNF-α, and VEGF Induced by Olanzapine on the Spleen of Adult Male Albino Rats and the Possible Protective Role of Vitamin C
Olanzapine is an antipsychotic drug effective in the treatment of stress-associated psychiatric illnesses, but its effect on the spleen remains unclear. Vitamin C is essential for the optimum function of the immune system. We aim to investigate the effect of Olanzapine on spleen structures and to assess the protective effect of vitamin C. Forty adult male albino rats were divided into four groups: group (I), a control; group (II), rats were given vitamin C at 40 mg/kg body weight; group (III), rats were given Olanzapine at 2 mg/kg body weight; and group (IV), rats were given vitamin C and Olanzapine at the same dose of group (II) and group (III) for one month. The hematoxylin and eosin (H&E) of the olanzapine treated group showed focal areas of cellular depletion and a decrease in the size of the white pulp. The red pulp was expanded and showed marked congestion and dilatation of blood sinusoids. Cluster of differentiation 3 (CD3) was significantly reduced, however both tumor necrosis factor alpha (TNF-α), and vascular endothelial growth factor (VEGF) were significantly higher. The administration of vitamin C repaired structural and immunohistochemical changes via increased CD3 and decreased TNF-α and VEGF. Therefore, the oxidative and the inflammatory pathways may be the possible mechanisms underlying olanzapine immunotoxicity. Vitamin C exerted immune modulator and antioxidant effects against olanzapine.
Biomedicines, Vol. 7, Pages 38: Hosts for Hostile Protein Production: The Challenge of Recombinant Immunotoxin Expression
For the recombinant expression of toxin-based drugs, a crucial step lies not only in the choice of the production host(s) but also in the accurate design of the protein chimera. These issues are particularly important since such products may be toxic to the expressing host itself. To avoid or limit the toxicity to productive cells while obtaining a consistent yield in chimeric protein, several systems from bacterial to mammalian host cells have been employed. In this review, we will discuss the development of immunotoxin (IT) expression, placing special emphasis on advantages and on potential drawbacks, as one single perfect host for every chimeric protein toxin or ligand does not exist.
Biomedicines, Vol. 7, Pages 37: Evaluation of Angiogenesis Assays
Angiogenesis assays allow for the evaluation of pro- or anti-angiogenic activity of endogenous or exogenous factors (stimulus or inhibitors) through investigation of their pro-or anti- proliferative, migratory, and tube formation effects on endothelial cells. To model the process of angiogenesis and the effects of biomolecules on that process, both in vitro and in vivo methods are currently used. In general, in vitro methods monitor specific stages in the angiogenesis process and are used for early evaluations, while in vivo methods more accurately simulate the living microenvironment to provide more pertinent information. We review here the current state of angiogenesis assays as well as their mechanisms, advantages, and limitations.

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