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Biomolecules, Volume 9, Issue 8 (August 2019)

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Cover Story (view full-size image) Primordial germ cells (PGCs), the progenitors of gametes, migrate to genital ridges during early [...] Read more.
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Open AccessFeature PaperReview
A Stage-Based Approach to Therapy in Parkinson’s Disease
Biomolecules 2019, 9(8), 388; https://doi.org/10.3390/biom9080388 - 20 Aug 2019
Viewed by 526
Abstract
Parkinson’s disease (PD) is a neurodegenerative disorder that features progressive, disabling motor symptoms, such as bradykinesia, rigidity, and resting tremor. Nevertheless, some non-motor symptoms, including depression, REM sleep behavior disorder, and olfactive impairment, are even earlier features of PD. At later stages, apathy, [...] Read more.
Parkinson’s disease (PD) is a neurodegenerative disorder that features progressive, disabling motor symptoms, such as bradykinesia, rigidity, and resting tremor. Nevertheless, some non-motor symptoms, including depression, REM sleep behavior disorder, and olfactive impairment, are even earlier features of PD. At later stages, apathy, impulse control disorder, neuropsychiatric disturbances, and cognitive impairment can present, and they often become a heavy burden for both patients and caregivers. Indeed, PD increasingly compromises activities of daily life, even though a high variability in clinical presentation can be observed among people affected. Nowadays, symptomatic drugs and non-pharmaceutical treatments represent the best therapeutic options to improve quality of life in PD patients. The aim of the present review is to provide a practical, stage-based guide to pharmacological management of both motor and non-motor symptoms of PD. Furthermore, warning about drug side effects, contraindications, as well as dosage and methods of administration, are highlighted here, to help the physician in yielding the best therapeutic strategies for each symptom and condition in patients with PD. Full article
(This article belongs to the Special Issue Advances in Parkinson's Disease Drugs)
Open AccessReview
Stabilin Receptors: Role as Phosphatidylserine Receptors
Biomolecules 2019, 9(8), 387; https://doi.org/10.3390/biom9080387 - 20 Aug 2019
Viewed by 480
Abstract
Phosphatidylserine is a membrane phospholipid that is localized to the inner leaflet of the plasma membrane. Phosphatidylserine externalization to the outer leaflet of the plasma membrane is an important signal for various physiological processes, including apoptosis, platelet activation, cell fusion, lymphocyte activation, and [...] Read more.
Phosphatidylserine is a membrane phospholipid that is localized to the inner leaflet of the plasma membrane. Phosphatidylserine externalization to the outer leaflet of the plasma membrane is an important signal for various physiological processes, including apoptosis, platelet activation, cell fusion, lymphocyte activation, and regenerative axonal fusion. Stabilin-1 and stabilin-2 are membrane receptors that recognize phosphatidylserine on the cell surface. Here, we discuss the functions of Stabilin-1 and stabilin-2 as phosphatidylserine receptors in apoptotic cell clearance (efferocytosis) and cell fusion, and their ligand-recognition and signaling pathways. Full article
(This article belongs to the Special Issue Physiological Functions of Stabilin Receptors)
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Open AccessArticle
Proinflammatory Action of a New Electronegative Low-Density Lipoprotein Epitope
Biomolecules 2019, 9(8), 386; https://doi.org/10.3390/biom9080386 - 20 Aug 2019
Viewed by 410
Abstract
The electronegative low-density lipoprotein, LDL (−), is an endogenously modified LDL subfraction with cytotoxic and proinflammatory actions on endothelial cells, monocytes, and macrophages contributing to the progression of atherosclerosis. In this study, epitopes of LDL (−) were mapped using a phage display library [...] Read more.
The electronegative low-density lipoprotein, LDL (−), is an endogenously modified LDL subfraction with cytotoxic and proinflammatory actions on endothelial cells, monocytes, and macrophages contributing to the progression of atherosclerosis. In this study, epitopes of LDL (−) were mapped using a phage display library of peptides and monoclonal antibodies reactive to this modified lipoprotein. Two different peptide libraries (X6 and CX8C for 6- and 8-amino acid-long peptides, respectively) were used in the mapping. Among all tested peptides, two circular peptides, P1A3 and P2C7, were selected based on their high affinities for the monoclonal antibodies. Small-angle X-ray scattering analysis confirmed their structures as circular rings. P1A3 or P2C7 were quickly internalized by bone marrow-derived murine macrophages as shown by confocal microscopy. P2C7 increased the expression of TNFα, IL-1 β and iNOS as well as the secretion of TNFα, CCL2, and nitric oxide by murine macrophages, similar to the responses induced by LDL (−), although less intense. In contrast, P1A3 did not show pro-inflammatory effects. We identified a mimetic epitope associated with LDL (−), the P2C7 circular peptide, that activates macrophages. Our data suggest that this conformational epitope represents an important danger-associated molecular pattern of LDL (−) that triggers proinflammatory responses. Full article
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Open AccessFeature PaperReview
Unchain My Blood: Lessons Learned from Self-Assembled Dendrimers as Nanoscale Heparin Binders
Biomolecules 2019, 9(8), 385; https://doi.org/10.3390/biom9080385 - 20 Aug 2019
Viewed by 319
Abstract
This review work reports a collection of coupled experimental/computational results taken from our own experience in the field of self-assembled dendrimers for heparin binding. These studies present and discuss both the potentiality played by this hybrid methodology to the design, synthesis, and development [...] Read more.
This review work reports a collection of coupled experimental/computational results taken from our own experience in the field of self-assembled dendrimers for heparin binding. These studies present and discuss both the potentiality played by this hybrid methodology to the design, synthesis, and development of possible protamine replacers for heparin anticoagulant activity reversal in biomedical applications, and the obstacles this field has still to overcome before these molecules can be translated into nanomedicines available in clinical settings. Full article
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Open AccessArticle
Study of the Combination of Self-Activating Photodynamic Therapy and Chemotherapy for Cancer Treatment
Biomolecules 2019, 9(8), 384; https://doi.org/10.3390/biom9080384 - 20 Aug 2019
Viewed by 611
Abstract
Cancer is a very challenging disease to treat, both in terms of treatment efficiency and side-effects. To overcome these problems, there have been extensive studies regarding the possibility of improving treatment by employing combination therapy, and by exploring therapeutic modalities with reduced side-effects [...] Read more.
Cancer is a very challenging disease to treat, both in terms of treatment efficiency and side-effects. To overcome these problems, there have been extensive studies regarding the possibility of improving treatment by employing combination therapy, and by exploring therapeutic modalities with reduced side-effects (such as photodynamic therapy (PDT)). Herein, this work has two aims: (i) to develop self-activating photosensitizers for use in light-free photodynamic therapy, which would eliminate light-related restrictions that this therapy currently possesses; (ii) to assess their co-treatment potential when combined with reference chemotherapeutic agents (Tamoxifen and Metformin). We synthesized three new photosensitizers capable of self-activation and singlet oxygen production via a chemiluminescent reaction involving only a cancer marker and without requiring a light source. Cytotoxicity assays demonstrated the cytotoxic activity of all photosensitizers for prostate and breast tumor cell lines. Analysis of co-treatment effects revealed significant improvements for breast cancer, producing better results for all combinations than just for the individual photosensitizers and even Tamoxifen. By its turn, co-treatment for prostate cancer only presented better results for one combination than for just the isolated photosensitizers and Metformin. Nevertheless, it should be noted that the cytotoxicity of the isolated photosensitizers in prostate tumor cells was already very appreciable. Full article
(This article belongs to the Special Issue Multidrug Combinations)
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Open AccessArticle
Preparation and Coagulation Performance of Carboxypropylated and Carboxypentylated Lignosulfonates for Dye Removal
Biomolecules 2019, 9(8), 383; https://doi.org/10.3390/biom9080383 - 20 Aug 2019
Viewed by 310
Abstract
In this work, 1-carboxypropyled (1-CPRLS) and 5-carboxypentyled lignosulfonates (5-CPELS) were synthesized using 2-chlorobutanoic acid and 6-chlorohexanoic acid as carboxylate group donors via SN1 and SN2 mechanisms, respectively. 1-Carboxypropyl and 5-carboxypentyl lignosulfonates with the charge densities of −3.45 and −2.94 [...] Read more.
In this work, 1-carboxypropyled (1-CPRLS) and 5-carboxypentyled lignosulfonates (5-CPELS) were synthesized using 2-chlorobutanoic acid and 6-chlorohexanoic acid as carboxylate group donors via SN1 and SN2 mechanisms, respectively. 1-Carboxypropyl and 5-carboxypentyl lignosulfonates with the charge densities of −3.45 and −2.94 meq g−1 and molecular weights of 87,900 and 42,400 g·mol−1 were produced, respectively, under mild conditions. The carboxylate content and degree of substitution (DS) of the 1-CPRLS product were 2.37 mmol·g−1 and 0.70 mol·mol−1, while those of 5-CPELS products were 2.13 mmol·g−1 and 0.66 mol·mol−1, respectively. The grafting of carboxypropyl and carboxypentyl groups to lignosulfonate was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR and 13C-NMR) spectroscopies. In addition, 1-CPRLS and 5-CPELS were applied as coagulants for removing ethyl violet (EV) dye from a simulated solution, and their performance was related to their charge densities and molecular weights. Furthermore, fundamental discussion is provided on the advantages of (1) producing 1-CPRLS and (2) the superior properties and performance of 1-CPRLS to carboxyethylated lignosulfonate. Full article
(This article belongs to the Section Natural and Bio-inspired Molecules)
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Open AccessArticle
Thimet Oligopeptidase (EC 3.4.24.15) Key Functions Suggested by Knockout Mice Phenotype Characterization
Biomolecules 2019, 9(8), 382; https://doi.org/10.3390/biom9080382 - 19 Aug 2019
Viewed by 439
Abstract
Thimet oligopeptidase (THOP1) is thought to be involved in neuropeptide metabolism, antigen presentation, neurodegeneration, and cancer. Herein, the generation of THOP1 C57BL/6 knockout mice (THOP1−/−) is described showing that they are viable, have estrus cycle, fertility, and a number of puppies [...] Read more.
Thimet oligopeptidase (THOP1) is thought to be involved in neuropeptide metabolism, antigen presentation, neurodegeneration, and cancer. Herein, the generation of THOP1 C57BL/6 knockout mice (THOP1−/−) is described showing that they are viable, have estrus cycle, fertility, and a number of puppies per litter similar to C57BL/6 wild type mice (WT). In specific brain regions, THOP1-/- exhibit altered mRNA expression of proteasome beta5, serotonin 5HT2a receptor and dopamine D2 receptor, but not of neurolysin (NLN). Peptidomic analysis identifies differences in intracellular peptide ratios between THOP1-/- and WT mice, which may affect normal cellular functioning. In an experimental model of multiple sclerosis THOP1-/- mice present worse clinical behavior scores compared to WT mice, corroborating its possible involvement in neurodegenerative diseases. THOP1-/- mice also exhibit better survival and improved behavior in a sepsis model, but also a greater peripheral pain sensitivity measured in the hot plate test after bradykinin administration in the paw. THOP1-/- mice show depressive-like behavior, as well as attention and memory retention deficits. Altogether, these results reveal a role of THOP1 on specific behaviors, immune-stimulated neurodegeneration, and infection-induced inflammation. Full article
(This article belongs to the Section Biochemistry)
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Open AccessFeature PaperArticle
Effect of Photobiomodulation in Rescuing Lipopolysaccharide-Induced Dopaminergic Cell Loss in the Male Sprague–Dawley Rat
Biomolecules 2019, 9(8), 381; https://doi.org/10.3390/biom9080381 - 19 Aug 2019
Viewed by 509
Abstract
Photobiomodulation (PBM) provides neuroprotection against dopaminergic cell death and associated motor deficits in rodent and primate models of Parkinson’s disease (PD). However, it has not yet been tested in the lipopolysaccharide (LPS) model of PD, which leads to dopaminergic cell death through microglia-evoked [...] Read more.
Photobiomodulation (PBM) provides neuroprotection against dopaminergic cell death and associated motor deficits in rodent and primate models of Parkinson’s disease (PD). However, it has not yet been tested in the lipopolysaccharide (LPS) model of PD, which leads to dopaminergic cell death through microglia-evoked neuroinflammation. We investigated whether transcranial PBM could protect against dopaminergic cell death within the substantia nigra in male Sprague–Dawley rats following supranigral LPS injection. PBM fully protected rats from 10 µg LPS which would have otherwise caused 15% cell loss, but there was no significant neuroprotection at a 20 µg dose that led to a 50% lesion. Cell loss at this dose varied according to the precise site of injection and correlated with increased local numbers of highly inflammatory amoeboid microglia. Twenty microgram LPS caused motor deficits in the cylinder, adjusted stepping and rotarod tests that correlated with dopaminergic cell loss. While PBM caused no significant improvement at the group level, motor performance on all three tests no longer correlated with the lesion size caused by 20 µg LPS in PBM-treated rats, suggesting extranigral motor improvements in some animals. These results provide support for PBM as a successful neuroprotective therapy against the inflammatory component of early PD, provided inflammation has not reached a devastating level, as well as potential benefits in other motor circuitries. Full article
(This article belongs to the Special Issue Photobiomodulation for Parkinson's Disease)
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Open AccessArticle
The Protective Effect of Hispidin against Hydrogen Peroxide-Induced Oxidative Stress in ARPE-19 Cells via Nrf2 Signaling Pathway
Biomolecules 2019, 9(8), 380; https://doi.org/10.3390/biom9080380 - 19 Aug 2019
Viewed by 445
Abstract
Hispidin, a polyphenol compound isolated from Phellinus linteus, has been reported to possess antioxidant activities. In this study, we aimed to investigate the mechanisms underlying the protective effect of hispidin against hydrogen peroxide (H2O2)-induced oxidative stress on Adult [...] Read more.
Hispidin, a polyphenol compound isolated from Phellinus linteus, has been reported to possess antioxidant activities. In this study, we aimed to investigate the mechanisms underlying the protective effect of hispidin against hydrogen peroxide (H2O2)-induced oxidative stress on Adult Retinal Pigment Epithelial cell line-19 (ARPE-19) cells. Hispidin was not cytotoxic to ARPE-19 cells at concentrations of less than 50 μM. The levels of intracellular reactive oxygen species (ROS) were analyzed by dichlorofluorescin diacetate (DCFDA) staining. Hispidin significantly restored H2O2-induced cell death and reduced the levels of intracellular ROS. The expression levels of antioxidant enzymes, such as NAD(P)H:Quinine oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (GCLC), and glutamate-cysteine ligase modifier subunit (GCLM) were examined using real-time PCR and Western blotting. Our results showed that hispidin markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), HO-1, NQO-1, GCLM, and GCLC in a dose-dependent manner. Furthermore, knockdown experiments revealed that transfection with Nrf2 siRNA successfully suppresses the hispidin activated Nrf2 signaling in ARPE-19 cells. Moreover, activation of the c-Jun N-terminal kinase (JNK) pathway is involved in mediating the protective effects of hispidin on the ARPE-19 cells. Thus, the present study demonstrated that hispidin provides protection against H2O2-induced damage in ARPE-19 cells via activation of Nrf2 signaling and up-regulation of its downstream targets, including Phase II enzymes, which might be associated with the activation of the JNK pathway. Full article
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Open AccessArticle
Exploring Structure-Activity Relationship in Tacrine-Squaramide Derivatives as Potent Cholinesterase Inhibitors
Biomolecules 2019, 9(8), 379; https://doi.org/10.3390/biom9080379 - 19 Aug 2019
Viewed by 382
Abstract
Tacrine was the first drug to be approved for Alzheimer’s disease (AD) treatment, acting as a cholinesterase inhibitor. The neuropathological hallmarks of AD are amyloid-rich senile plaques, neurofibrillary tangles, and neuronal degeneration. The portfolio of currently approved drugs for AD includes acetylcholinesterase inhibitors [...] Read more.
Tacrine was the first drug to be approved for Alzheimer’s disease (AD) treatment, acting as a cholinesterase inhibitor. The neuropathological hallmarks of AD are amyloid-rich senile plaques, neurofibrillary tangles, and neuronal degeneration. The portfolio of currently approved drugs for AD includes acetylcholinesterase inhibitors (AChEIs) and N-methyl-d-aspartate (NMDA) receptor antagonist. Squaric acid is a versatile structural scaffold capable to be easily transformed into amide-bearing compounds that feature both hydrogen bond donor and acceptor groups with the possibility to create multiple interactions with complementary sites. Considering the relatively simple synthesis approach and other interesting properties (rigidity, aromatic character, H-bond formation) of squaramide motif, we combined this scaffold with different tacrine-based derivatives. In this study, we developed 21 novel dimers amalgamating squaric acid with either tacrine, 6-chlorotacrine or 7-methoxytacrine representing various AChEIs. All new derivatives were evaluated for their anti-cholinesterase activities, cytotoxicity using HepG2 cell line and screened to predict their ability to cross the blood-brain barrier. In this contribution, we also report in silico studies of the most potent AChE and BChE inhibitors in the active site of these enzymes. Full article
(This article belongs to the Special Issue Advances in Cholinesterases)
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Open AccessReview
There Is Treasure Everywhere: Reductive Plastid Evolution in Apicomplexa in Light of Their Close Relatives
Biomolecules 2019, 9(8), 378; https://doi.org/10.3390/biom9080378 - 19 Aug 2019
Viewed by 622
Abstract
The phylum Apicomplexa (Alveolates) comprises a group of host-associated protists, predominately intracellular parasites, including devastating parasites like Plasmodium falciparum, the causative agent of malaria. One of the more fascinating characteristics of Apicomplexa is their highly reduced (and occasionally lost) remnant plastid, termed [...] Read more.
The phylum Apicomplexa (Alveolates) comprises a group of host-associated protists, predominately intracellular parasites, including devastating parasites like Plasmodium falciparum, the causative agent of malaria. One of the more fascinating characteristics of Apicomplexa is their highly reduced (and occasionally lost) remnant plastid, termed the apicoplast. Four core metabolic pathways are retained in the apicoplast: heme synthesis, iron–sulfur cluster synthesis, isoprenoid synthesis, and fatty acid synthesis. It has been suggested that one or more of these pathways are essential for plastid and plastid genome retention. The past decade has witnessed the discovery of several apicomplexan relatives, and next-generation sequencing efforts are revealing that they retain variable plastid metabolic capacities. These data are providing clues about the core genes and pathways of reduced plastids, while at the same time further confounding our view on the evolutionary history of the apicoplast. Here, we examine the evolutionary history of the apicoplast, explore plastid metabolism in Apicomplexa and their close relatives, and propose that the differences among reduced plastids result from a game of endosymbiotic roulette. Continued exploration of the Apicomplexa and their relatives is sure to provide new insights into the evolution of the apicoplast and apicomplexans as a whole. Full article
(This article belongs to the Special Issue Evolutionary and Molecular Aspects of Plastid Endosymbioses)
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Open AccessReview
Changes in Mitochondrial Genome Associated with Predisposition to Atherosclerosis and Related Disease
Biomolecules 2019, 9(8), 377; https://doi.org/10.3390/biom9080377 - 18 Aug 2019
Cited by 1 | Viewed by 463
Abstract
Atherosclerosis-related cardiovascular diseases remain the leading cause of morbidity and mortality, and the search for novel diagnostic and therapeutic methods is ongoing. Mitochondrial DNA (mtDNA) mutations associated with atherosclerosis represent one of the less explored aspects of the disease pathogenesis that may bring [...] Read more.
Atherosclerosis-related cardiovascular diseases remain the leading cause of morbidity and mortality, and the search for novel diagnostic and therapeutic methods is ongoing. Mitochondrial DNA (mtDNA) mutations associated with atherosclerosis represent one of the less explored aspects of the disease pathogenesis that may bring some interesting opportunities for establishing novel molecular markers and, possibly, new points of therapeutic intervention. Recent studies have identified a number of mtDNA mutations, for which the heteroplasmy level was positively or negatively associated with atherosclerosis, including the disease at its early, subclinical stages. In this review, we summarize the results of these studies, providing a list of human mtDNA mutations potentially involved in atherosclerosis. The molecular mechanisms underlying such involvement remain to be elucidated, although it is likely that some of them may be responsible for the increased oxidative stress, which plays an important role in atherosclerosis. Full article
Open AccessArticle
Aortic Oxidative Stress, Inflammation and DNA Damage Following Pulmonary Exposure to Cerium Oxide Nanoparticles in a Rat Model of Vascular Injury
Biomolecules 2019, 9(8), 376; https://doi.org/10.3390/biom9080376 - 17 Aug 2019
Viewed by 404
Abstract
Pulmonary exposure to cerium oxide nanoparticles (CeO2 NPs) can occur either at the workplace, or due to their release in the environment. Inhaled CeO2 NPs are known to cross the alveolar–capillary barrier and reach various parts of the body, including the [...] Read more.
Pulmonary exposure to cerium oxide nanoparticles (CeO2 NPs) can occur either at the workplace, or due to their release in the environment. Inhaled CeO2 NPs are known to cross the alveolar–capillary barrier and reach various parts of the body, including the vasculature. The anticancer drug cisplatin (CP) causes vascular damage. However, the effects CeO2 NPs on vascular homeostasis in a rat model of CP-induced vascular injury remain unclear. Here, we assessed the impact and underlying mechanism of pulmonary exposure to CeO2 NPs on aorta in rats given a single intraperitoneal injection of cisplatin (CP, 6 mg/kg) to induce vascular damage. Six days later, the rats were intratracheally instilled with either CeO2 NPs (1 mg/kg) or saline (control), and various variables were studied 24 h thereafter in the aortic tissue. The concentration of reduced glutathione and the activity of catalase were significantly increased in the CP + CeO2 NPs group compared with both the CP + saline and the CeO2 NPs groups. The activity of superoxide dismutase was significantly decreased in the CP + CeO2 NPs group compared with both the CP + saline and CeO2 NPs groups. The expression of nuclear factor erythroid-derived 2-like 2 (Nrf2) by the nuclei of smooth muscles and endocardial cells assessed by immunohistochemistry was significantly augmented in CeO2 NPs versus saline, in CP + saline versus saline, and in CP + CeO2 NPs versus CeO2 NPs. Moreover, the concentrations of total nitric oxide, lipid peroxidation and 8-hydroxy-2-deoxyguanosine were significantly elevated in the CP + CeO2 NPs group compared with both the CP + saline and the CeO2 NPs groups. Similarly, compared with both the CP + saline and CeO2 NPs groups, the combination of CP and CeO2 NPs significantly elevated the concentrations of interleukin-6 and tumour necrosis factor-α. Additionally, aortic DNA damage assessed by Comet assay was significantly increased in CeO2 NPs compared with saline, and in CP + saline versus saline, and all these effects were significantly aggravated by the combination of CP and CeO2 NPs. We conclude that pulmonary exposure to CeO2 NPs aggravates vascular toxicity in animal model of vascular injury through mechanisms involving oxidative stress, Nrf2 expression, inflammation and DNA damage. Full article
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Open AccessArticle
Inactivation of Aldehyde Dehydrogenase by Disulfiram in the Presence and Absence of Lipoic Acid or Dihydrolipoic Acid: An in Vitro Study
Biomolecules 2019, 9(8), 375; https://doi.org/10.3390/biom9080375 - 16 Aug 2019
Viewed by 379
Abstract
The inhibition of aldehyde dehydrogenase (ALDH) by disulfiram (DSF) in vitro can be prevented and/or reversed by dithiothreitol (DTT), which is a well-known low molecular weight non-physiological redox reagent commonly used in laboratory experiments. These observations inspired us to ask the question whether [...] Read more.
The inhibition of aldehyde dehydrogenase (ALDH) by disulfiram (DSF) in vitro can be prevented and/or reversed by dithiothreitol (DTT), which is a well-known low molecular weight non-physiological redox reagent commonly used in laboratory experiments. These observations inspired us to ask the question whether the inhibition of ALDH by DSF can be preserved or abolished also by dihydrolipoic acid (DHLA), which is the only currently known low molecular weight physiological dithiol in the body of humans and other animals. It can even be metaphorized that DHLA is an “endogenous DTT”. Lipoic acid (LA) is the oxidized form of DHLA. We investigated the inactivation of ALDH derived from yeast and rat liver by DSF in the presence or absence of LA or DHLA. The results clearly show that DHLA is able both to restore and protect ALDH activity blocked by DSF. The proposed mechanism is discussed. Full article
(This article belongs to the Section Biochemistry)
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Open AccessArticle
Proteomic Insights into Phycobilisome Degradation, A Selective and Tightly Controlled Process in The Fast-Growing Cyanobacterium Synechococcus elongatus UTEX 2973
Biomolecules 2019, 9(8), 374; https://doi.org/10.3390/biom9080374 - 16 Aug 2019
Viewed by 580
Abstract
Phycobilisomes (PBSs) are large (3–5 megadalton) pigment-protein complexes in cyanobacteria that associate with thylakoid membranes and harvest light primarily for photosystem II. PBSs consist of highly ordered assemblies of pigmented phycobiliproteins (PBPs) and linker proteins that can account for up to half of [...] Read more.
Phycobilisomes (PBSs) are large (3–5 megadalton) pigment-protein complexes in cyanobacteria that associate with thylakoid membranes and harvest light primarily for photosystem II. PBSs consist of highly ordered assemblies of pigmented phycobiliproteins (PBPs) and linker proteins that can account for up to half of the soluble protein in cells. Cyanobacteria adjust to changing environmental conditions by modulating PBS size and number. In response to nutrient depletion such as nitrogen (N) deprivation, PBSs are degraded in an extensive, tightly controlled, and reversible process. In Synechococcus elongatus UTEX 2973, a fast-growing cyanobacterium with a doubling time of two hours, the process of PBS degradation is very rapid, with 80% of PBSs per cell degraded in six hours under optimal light and CO2 conditions. Proteomic analysis during PBS degradation and re-synthesis revealed multiple proteoforms of PBPs with partially degraded phycocyanobilin (PCB) pigments. NblA, a small proteolysis adaptor essential for PBS degradation, was characterized and validated with targeted mass spectrometry. NblA levels rose from essentially 0 to 25,000 copies per cell within 30 min of N depletion, and correlated with the rate of decrease in phycocyanin (PC). Implications of this correlation on the overall mechanism of PBS degradation during N deprivation are discussed. Full article
(This article belongs to the Section Natural and Bio-inspired Molecules)
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Open AccessBrief Report
Human FcRn Tissue Expression Profile and Half-Life in PBMCs
Biomolecules 2019, 9(8), 373; https://doi.org/10.3390/biom9080373 - 15 Aug 2019
Viewed by 846
Abstract
System-wide quantitative characterization of human neonatal Fc receptor (FcRn) properties is critical for understanding and predicting human PK (pharmacokinetics) as well as the distribution of mAbs and Fc-fusion proteins using PBPK (physiologically-based pharmacokinetic) modeling. To this end, tissue-specific FcRn expression and half-life are [...] Read more.
System-wide quantitative characterization of human neonatal Fc receptor (FcRn) properties is critical for understanding and predicting human PK (pharmacokinetics) as well as the distribution of mAbs and Fc-fusion proteins using PBPK (physiologically-based pharmacokinetic) modeling. To this end, tissue-specific FcRn expression and half-life are important model inputs. Herein, human FcRn tissue expression was measured by peptide immunoaffinity chromatography coupled with high-resolution mass spectrometry. FcRn concentrations across 14 human tissues ranged from low to 230 pmol per gram of tissue. Furthermore, the FcRn half-life was determined to be 11.1 h from a human stable isotope labelled leucine pulse labeling experiment. The spatial and temporal quantitative human FcRn data now promise to enable a refined PBPK model with improved accuracy of human PK predictions for Fc-containing biotherapeutics. Full article
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Open AccessArticle
Gold Nanoparticle Size-Dependent Enhanced Chemiluminescence for Ultra-Sensitive Haptoglobin Biomarker Detection
Biomolecules 2019, 9(8), 372; https://doi.org/10.3390/biom9080372 - 14 Aug 2019
Viewed by 499
Abstract
Bovine mastitis (BM) is a frequent disease in the dairy industry that causes staggering economical losses due to decreased milk production and increased health care costs. Traditionally, BM detection depends on the efficacy and reliability of analytical techniques that measure somatic cell counts [...] Read more.
Bovine mastitis (BM) is a frequent disease in the dairy industry that causes staggering economical losses due to decreased milk production and increased health care costs. Traditionally, BM detection depends on the efficacy and reliability of analytical techniques that measure somatic cell counts (SCC), detect pathogens, and reveal inflammatory status. Herein, we demonstrate the detection of bovine haptoglobin, a well-documented acute phase protein for evaluating BM clinical status, by utilizing hemoglobin-binding capacity within luminol chemiluminescence (CL) system. The resulting haptoglobin–hemoglobin complex reduces the CL signal proportionally to inherent haptoglobin concentrations. Different sizes of cross-linked gold nanoparticles (GNPs) were examined for enhanced CL (eCL) signal amplification, presenting over 30-fold emitted radiation enhancement for optimized size within real milk samples with respect to nanoparticle-free assay. The eCL values were proportionally related to nanoparticle size and content, influenced by SCC and pathogen type (e.g., Escherichia coli and coagulase-negative staphylococci). The optimized bioassay showed a broad linear response (1 pg mL−1–10 µg mL−1) and minute detection limit of 0.19 pg mL−1, while presenting quantitative performance in agreement with commercial ELISA kit. Finally, the resulting optimized eCL concept offers an efficient label-free detection of haptoglobin biomarker, offering means to diagnose the severity of the associated diseases. Full article
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Open AccessCommunication
Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions
Biomolecules 2019, 9(8), 371; https://doi.org/10.3390/biom9080371 - 14 Aug 2019
Viewed by 510
Abstract
The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between [...] Read more.
The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites. Full article
(This article belongs to the Section Molecular Structure and Dynamics)
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Open AccessFeature PaperReview
Integrative Approaches in Structural Biology: A More Complete Picture from the Combination of Individual Techniques
Biomolecules 2019, 9(8), 370; https://doi.org/10.3390/biom9080370 - 14 Aug 2019
Viewed by 583
Abstract
With the recent technological and computational advancements, structural biology has begun to tackle more and more difficult questions, including complex biochemical pathways and transient interactions among macromolecules. This has demonstrated that, to approach the complexity of biology, one single technique is largely insufficient [...] Read more.
With the recent technological and computational advancements, structural biology has begun to tackle more and more difficult questions, including complex biochemical pathways and transient interactions among macromolecules. This has demonstrated that, to approach the complexity of biology, one single technique is largely insufficient and unable to yield thorough answers, whereas integrated approaches have been more and more adopted with successful results. Traditional structural techniques (X-ray crystallography and Nuclear Magnetic Resonance (NMR)) and the emerging ones (cryo-electron microscopy (cryo-EM), Small Angle X-ray Scattering (SAXS)), together with molecular modeling, have pros and cons which very nicely complement one another. In this review, three examples of synergistic approaches chosen from our previous research will be revisited. The first shows how the joint use of both solution and solid-state NMR (SSNMR), X-ray crystallography, and cryo-EM is crucial to elucidate the structure of polyethylene glycol (PEG)ylated asparaginase, which would not be obtainable through any of the techniques taken alone. The second deals with the integrated use of NMR, X-ray crystallography, and SAXS in order to elucidate the catalytic mechanism of an enzyme that is based on the flexibility of the enzyme itself. The third one shows how it is possible to put together experimental data from X-ray crystallography and NMR restraints in order to refine a protein model in order to obtain a structure which simultaneously satisfies both experimental datasets and is therefore closer to the ‘real structure’. Full article
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Open AccessReview
Post-Translational Modifications in NETosis and NETs-Mediated Diseases
Biomolecules 2019, 9(8), 369; https://doi.org/10.3390/biom9080369 - 14 Aug 2019
Viewed by 727
Abstract
Neutrophils undergo a unique form of cell death that generates neutrophil extracellular traps (NETs) that may help to neutralize invading pathogens and restore homeostasis. However, uncontrolled NET formation (NETosis) can result in numerous diseases that adversely affect health. Recent studies further elucidate the [...] Read more.
Neutrophils undergo a unique form of cell death that generates neutrophil extracellular traps (NETs) that may help to neutralize invading pathogens and restore homeostasis. However, uncontrolled NET formation (NETosis) can result in numerous diseases that adversely affect health. Recent studies further elucidate the mechanistic details of the different forms of NETosis and their common end structure, as NETs were constantly found to contain DNA, modified histones and cytotoxic enzymes. In fact, emerging evidence reveal that the post translational modifications (PTMs) of histones in neutrophils have a critical role in regulating neutrophil death. Histone citrullination is shown to promote a rapid form of NET formation independent of NADPH oxidase (NOX), which relies on calcium influx. Interestingly, few studies suggest an association between histone citrullination and other types of PTMs to control cell survival and death, such as histone methylation. Even more exciting is the finding that histone acetylation has a biphasic effect upon NETosis, where histone deacetylase (HDAC) inhibitors promote baseline, NOX-dependent and -independent NETosis. However, increasing levels of histone acetylation suppresses NETosis, and to switch neutrophil death to apoptosis. Interestingly, in the presence of NETosis-promoting stimuli, high levels of HDACis limit both NETosis and apoptosis, and promote neutrophil survival. Recent studies also reveal the importance of the PTMs of neutrophils in influencing numerous pathologies. Histone modifications in NETs can act as a double-edged sword, as they are capable of altering multiple types of neutrophil death, and influencing numerous NET-mediated diseases, such as acute lung injury (ALI), thrombosis, sepsis, systemic lupus erythematosus, and cancer progression. A clear understanding of the role of different PTMs in neutrophils would be important for an understanding of the molecular mechanisms of NETosis, and to appropriately treat NETs-mediated diseases. Full article
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Open AccessArticle
Heterodimerization of Mu Opioid Receptor Protomer with Dopamine D2 Receptor Modulates Agonist-Induced Internalization of Mu Opioid Receptor
Biomolecules 2019, 9(8), 368; https://doi.org/10.3390/biom9080368 - 14 Aug 2019
Viewed by 680
Abstract
The interplay between the dopamine (DA) and opioid systems in the brain is known to modulate the additive effects of substances of abuse. On one hand, opioids serve mankind by their analgesic properties, which are mediated via the mu opioid receptor (MOR), a [...] Read more.
The interplay between the dopamine (DA) and opioid systems in the brain is known to modulate the additive effects of substances of abuse. On one hand, opioids serve mankind by their analgesic properties, which are mediated via the mu opioid receptor (MOR), a Class A G protein-coupled receptor (GPCR), but on the other hand, they pose a potential threat by causing undesired side effects such as tolerance and dependence, for which the exact molecular mechanism is still unknown. Using human embryonic kidney 293T (HEK 293T) and HeLa cells transfected with MOR and the dopamine D2 receptor (D2R), we demonstrate that these receptors heterodimerize, using an array of biochemical and biophysical techniques such as coimmunoprecipitation (co-IP), bioluminescence resonance energy transfer (BRET1), Fӧrster resonance energy transfer (FRET), and functional complementation of a split luciferase. Furthermore, live cell imaging revealed that D2LR, when coexpressed with MOR, slowed down internalization of MOR, following activation with the MOR agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO). Full article
(This article belongs to the Special Issue Dopamine Receptor in Health and Diseases)
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Open AccessArticle
Ziziphora taurica subsp. taurica: Analytical Characterization and Biological Activities
Biomolecules 2019, 9(8), 367; https://doi.org/10.3390/biom9080367 - 14 Aug 2019
Viewed by 546
Abstract
The Lamiaceae family comprises many flowering plants classified into about 236 genera. The genus Ziziphora is one of the well-known genera of this family and its species are important in different fields of pharmaceutical, chemical, traditional, and folk medicines. The phytochemicals present in [...] Read more.
The Lamiaceae family comprises many flowering plants classified into about 236 genera. The genus Ziziphora is one of the well-known genera of this family and its species are important in different fields of pharmaceutical, chemical, traditional, and folk medicines. The phytochemicals present in Ziziphora include monoterpenic essential oils, triterpenes, and phenolic substances. The aim of this paper was to study the phytochemical profile of Ziziphora taurica subsp. taurica and compare and evaluate the biological activities of its ethyl acetate (ZTT-EtOAc), methanolic (ZTT-MeOH), and aqueous (ZTT-W) extracts based on their enzyme inhibition and antioxidant capacities. Determination of total phenolic (TPC) and total flavonoid (TFC) contents as well as biological activities were determined using spectrophotometric procedures. Subsequently, the individual phenolic compounds were detected by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS). In total, twenty-two different phenolic compounds were identified, including apigenin, ferulic acid, and luteolin which were the most common. ZTT-MeOH extract showed the best antioxidant activity, whereas ZTT-EtOAc extract was the most effective against tyrosinase and α-amylase. Ziziphora taurica subsp. taurica represents a potential source of natural compounds with positive effects on human health. Full article
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Open AccessArticle
The Early Phase of β2m Aggregation: An Integrative Computational Study Framed on the D76N Mutant and the ΔN6 Variant
Biomolecules 2019, 9(8), 366; https://doi.org/10.3390/biom9080366 - 14 Aug 2019
Viewed by 529
Abstract
Human β2-microglobulin (b2m) protein is classically associated with dialysis-related amyloidosis (DRA). Recently, the single point mutant D76N was identified as the causative agent of a hereditary systemic amyloidosis affecting visceral organs. To get insight into the early stage of the β2m aggregation mechanism, [...] Read more.
Human β2-microglobulin (b2m) protein is classically associated with dialysis-related amyloidosis (DRA). Recently, the single point mutant D76N was identified as the causative agent of a hereditary systemic amyloidosis affecting visceral organs. To get insight into the early stage of the β2m aggregation mechanism, we used molecular simulations to perform an in depth comparative analysis of the dimerization phase of the D76N mutant and the ΔN6 variant, a cleaved form lacking the first six N-terminal residues, which is a major component of ex vivo amyloid plaques from DRA patients. We also provide first glimpses into the tetramerization phase of D76N at physiological pH. Results from extensive protein–protein docking simulations predict an essential role of the C- and N-terminal regions (both variants), as well as of the BC-loop (ΔN6 variant), DE-loop (both variants) and EF-loop (D76N mutant) in dimerization. The terminal regions are more relevant under acidic conditions while the BC-, DE- and EF-loops gain importance at physiological pH. Our results recapitulate experimental evidence according to which Tyr10 (A-strand), Phe30 and His31 (BC-loop), Trp60 and Phe62 (DE-loop) and Arg97 (C-terminus) act as dimerization hot-spots, and further predict the occurrence of novel residues with the ability to nucleate dimerization, namely Lys-75 (EF-loop) and Trp-95 (C-terminus). We propose that D76N tetramerization is mainly driven by the self-association of dimers via the N-terminus and DE-loop, and identify Arg3 (N-terminus), Tyr10, Phe56 (D-strand) and Trp60 as potential tetramerization hot-spots. Full article
(This article belongs to the Section Molecular Structure and Dynamics)
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Open AccessReview
Neutrophil Extracellular Trap Formation: Physiology, Pathology, and Pharmacology
Biomolecules 2019, 9(8), 365; https://doi.org/10.3390/biom9080365 - 14 Aug 2019
Cited by 1 | Viewed by 667
Abstract
Neutrophil extracellular traps (NETs), a unique DNA framework decorated with antimicrobial peptides, have been in the scientific limelight for their role in a variety of pathologies ranging from cystic fibrosis to cancer. The formation of NETs, as well as relevant regulatory mechanisms, physiological [...] Read more.
Neutrophil extracellular traps (NETs), a unique DNA framework decorated with antimicrobial peptides, have been in the scientific limelight for their role in a variety of pathologies ranging from cystic fibrosis to cancer. The formation of NETs, as well as relevant regulatory mechanisms, physiological factors, and pharmacological agents have not been systematically discussed in the context of their beneficial and pathological aspects. Novel forms of NET formation including vital NET formation continue to be uncovered, however, there remain fundamental questions around established mechanisms such as NADPH-oxidase (Nox)-dependent and Nox-independent NET formation. Whether NET formation takes place in the tissue versus the bloodstream, internal factors (e.g. reactive oxygen species (ROS) production and transcription factor activation), and external factors (e.g. alkaline pH and hypertonic conditions), have all been demonstrated to influence specific NET pathways. Elements of neutrophil biology such as transcription and mitochondria, which were previously of unknown significance, have been identified as critical mediators of NET formation through facilitating chromatin decondensation and generating ROS, respectively. While promising therapeutics inhibiting ROS, transcription, and gasdermin D are being investigated, neutrophil phagocytosis plays a critical role in host defense and any therapies targeting NET formation must avoid impairing the physiological functions of these cells. This review summarizes what is known in the many domains of NET research, highlights the most relevant challenges in the field, and inspires new questions that can bring us closer to a unified model of NET formation. Full article
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Open AccessArticle
Identification of SWI2/SNF2-Related 1 Chromatin Remodeling Complex (SWR1-C) Subunits in Pineapple and the Role of Pineapple SWR1 COMPLEX 6 (AcSWC6) in Biotic and Abiotic Stress Response
Biomolecules 2019, 9(8), 364; https://doi.org/10.3390/biom9080364 - 13 Aug 2019
Viewed by 568
Abstract
Chromatin remodeling complex orchestrates numerous aspects of growth and development in eukaryotes. SWI2/SNF2-Related 1 chromatin remodeling complex (SWR1-C) is a member of the SWI/SNF ATPase-containing chromatin remodeling complex responsible for the exchange of H2A for H2A.Z. In plants, SWR1-C plays a crucial role [...] Read more.
Chromatin remodeling complex orchestrates numerous aspects of growth and development in eukaryotes. SWI2/SNF2-Related 1 chromatin remodeling complex (SWR1-C) is a member of the SWI/SNF ATPase-containing chromatin remodeling complex responsible for the exchange of H2A for H2A.Z. In plants, SWR1-C plays a crucial role by transcriptionally regulating numerous biological and developmental processes. However, SWR1-C activity remains obscure in pineapple. Here, we aim to identify the SWR1-C subunits in pineapple. By genome-wide identification, we found a total of 11 SWR1-C subunits in the pineapple. The identified SWR1-C subunits were named and classified based on the sequence similarity and phylogenetic analysis. RNA-Seq analysis showed that pineapple SWR1-C subunits are expressed differentially in different organs and at different stages. Additionally, the qRT-PCR of pineapple SWR1-C subunits during abiotic stress exposure showed significant changes in their expression. We further investigated the functions of pineapple SWR1 COMPLEX 6 (AcSWC6) by ectopically expressing it in Arabidopsis. Interestingly, transgenic plants ectopically expressing AcSWC6 showed susceptibility to fungal infection and enhanced resistance to salt and osmotic stress, revealing its involvement in biotic and abiotic stress. Moreover, the complementation of mutant Arabidopsis swc6 by pineapple SWC6 suggested the conserved function of SWC6 in plants. Full article
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Open AccessArticle
Wood-Based Cellulose Nanofibrils: Haemocompatibility and Impact on the Development and Behaviour of Drosophila melanogaster
Biomolecules 2019, 9(8), 363; https://doi.org/10.3390/biom9080363 - 13 Aug 2019
Viewed by 470
Abstract
Wood-based cellulose nanofibrils (CNF) offer an excellent scaffold for drug-delivery formulation development. However, toxicity and haemocompatibility of the drug carrier is always an important issue. In this study, toxicity-related issues of CNF were addressed. Different doses of CNF were orally administered to Drosophila [...] Read more.
Wood-based cellulose nanofibrils (CNF) offer an excellent scaffold for drug-delivery formulation development. However, toxicity and haemocompatibility of the drug carrier is always an important issue. In this study, toxicity-related issues of CNF were addressed. Different doses of CNF were orally administered to Drosophila and different tests like the developmental cycle, trypan blue exclusion assay, larva crawling assay, thermal sensitivity assay, cold sensitivity assay, larval light preference test, climbing behaviour, nitroblue tetrazolium (NBT) reduction assay, adult phenotype, and adult weight were conducted to observe the impact on its development and behaviour. A haemocompatibility assay was done on the blood taken from healthy Wistar rats. In Drosophila, the abnormalities in larval development and behaviour were observed in the behavioural assays. However, the cytotoxic effect could not be confirmed by the gut staining and level of reactive oxygen species. The larvae developed into an adult without any abnormality in the phenotype. The CNF did cause loss of weight in the adult flies and did not cause much toxicity within the body since there was no phenotypic defect. Hemolysis data also suggested that CNF was safe at lower doses, as the data was well within acceptable limits. All these results suggest that cellulose nanofibres have no significant cytotoxic effects on Drosophila. However, the developmental and behavioural abnormalities suggest that CNF may act as a behavioural teratogen. Full article
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Open AccessArticle
The Methodological Trends of Traditional Herbal Medicine Employing Network Pharmacology
Biomolecules 2019, 9(8), 362; https://doi.org/10.3390/biom9080362 - 13 Aug 2019
Cited by 1 | Viewed by 733
Abstract
Natural products, including traditional herbal medicine (THM), are known to exert their therapeutic effects by acting on multiple targets, so researchers have employed network pharmacology methods to decipher the potential mechanisms of THM. To conduct THM-network pharmacology (THM-NP) studies, researchers have employed different [...] Read more.
Natural products, including traditional herbal medicine (THM), are known to exert their therapeutic effects by acting on multiple targets, so researchers have employed network pharmacology methods to decipher the potential mechanisms of THM. To conduct THM-network pharmacology (THM-NP) studies, researchers have employed different tools and databases for constructing and analyzing herb–compound–target networks. In this study, we attempted to capture the methodological trends in THM-NP research. We identified the tools and databases employed to conduct THM-NP studies and visualized their combinatorial patterns. We also constructed co-author and affiliation networks to further understand how the methodologies are employed among researchers. The results showed that the number of THM-NP studies and employed databases/tools have been dramatically increased in the last decade, and there are characteristic patterns in combining methods of each analysis step in THM-NP studies. Overall, the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) was the most frequently employed network pharmacology database in THM-NP studies. Among the processes involved in THM-NP research, the methodology for constructing a compound–target network has shown the greatest change over time. In summary, our analysis describes comprehensive methodological trends and current ideas in research design for network pharmacology researchers. Full article
(This article belongs to the Special Issue Phytochemical Omics in Medicinal Plants)
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Open AccessArticle
The Natural-Based Antitumor Compound T21 Decreases Survivin Levels through Potent STAT3 Inhibition in Lung Cancer Models
Biomolecules 2019, 9(8), 361; https://doi.org/10.3390/biom9080361 - 13 Aug 2019
Viewed by 528
Abstract
Lung cancer is the leading cause of cancer-related deaths worldwide; hence novel treatments for this malignancy are eagerly needed. Since natural-based compounds represent a rich source of novel chemical entities in drug discovery, we have focused our attention on tambjamines, natural compounds isolated [...] Read more.
Lung cancer is the leading cause of cancer-related deaths worldwide; hence novel treatments for this malignancy are eagerly needed. Since natural-based compounds represent a rich source of novel chemical entities in drug discovery, we have focused our attention on tambjamines, natural compounds isolated from marine invertebrates that have shown diverse pharmacological activities. Based on these structures, we have recently identified the novel indole-based tambjamine analog 21 (T21) as a promising antitumor agent, which modulates the expression of apoptotic proteins such as survivin. This antiapoptotic protein plays an important role in carcinogenesis and chemoresistance. In this work, we have elucidated the molecular mechanism by which the anticancer compound T21 exerts survivin inhibition and have validated this protein as a therapeutic target in different lung cancer models. T21 was able to reduce survivin protein levels in vitro by repressing its gene expression through the blockade of Janus kinase/Signal Transducer and Activator of Transcription-3 (JAK/STAT3)/survivin signaling pathway. Interestingly, this occurred even when the pathway was overstimulated with its ligand interleukin 6 (IL-6), which is frequently overexpressed in lung cancer patients who show poor clinical outcomes. Altogether, these results show T21 as a potent anticancer compound that effectively decreases survivin levels through STAT3 inhibition in lung cancer, appearing as a promising therapeutic drug for cancer treatment. Full article
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Open AccessArticle
Anticancer Activity of Water-Soluble Olsalazine-PAMAM-Dendrimer-Salicylic Acid-Conjugates
Biomolecules 2019, 9(8), 360; https://doi.org/10.3390/biom9080360 - 13 Aug 2019
Viewed by 483
Abstract
Improving the activity and selectivity profile of anticancer agents will require designing drug carrier systems that employ soluble macromolecules. Olsalazine-PAMAM-dendrimer-salicylic acid-conjugates with dendritic arms of different lengths have shown good stability regarding the chemical link between drug and spacer. In this study, the [...] Read more.
Improving the activity and selectivity profile of anticancer agents will require designing drug carrier systems that employ soluble macromolecules. Olsalazine-PAMAM-dendrimer-salicylic acid-conjugates with dendritic arms of different lengths have shown good stability regarding the chemical link between drug and spacer. In this study, the drug release was followed in vitro by ultraviolet (UV) studies. Evaluation of the cytotoxicity of the olsalazine-PAMAM-dendrimer-salicylic acid-conjugates employing a sulforhodamine B (SRB) assay in PC-3 (human prostatic adenocarcinoma) and MCF-7 (human mammary adenocarcinoma) cell lines demonstrated that conjugate 9 was more active as an antiproliferative agent than cisplatin, and no cytotoxicity towards the African green monkey kidney fibroblast (COS-7) cell line was observed in any of the conjugates synthesized in the present work. Full article
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Open AccessArticle
Systematic FTIR Spectroscopy Study of the Secondary Structure Changes in Human Serum Albumin under Various Denaturation Conditions
Biomolecules 2019, 9(8), 359; https://doi.org/10.3390/biom9080359 - 12 Aug 2019
Viewed by 525
Abstract
Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data [...] Read more.
Human serum albumin (HSA) is the most abundant protein in blood plasma. HSA is involved in the transport of hormones, fatty acids, and some other compounds, maintenance of blood pH, osmotic pressure, and many other functions. Although this protein is well studied, data about its conformational changes upon different denaturation factors are fragmentary and sometimes contradictory. This is especially true for FTIR spectroscopy data interpretation. Here, the effect of various denaturing agents on the structural state of HSA by using FTIR spectroscopy in the aqueous solutions was systematically studied. Our data suggest that the second derivative deconvolution method provides the most consistent interpretation of the obtained IR spectra. The secondary structure changes of HSA were studied depending on the concentration of the denaturing agent during acid, alkaline, and thermal denaturation. In general, the denaturation of HSA in different conditions is accompanied by a decrease in α-helical conformation and an increase in random coil conformation and the intermolecular β-strands. Meantime, some variation in the conformational changes depending on the type of the denaturation agent were also observed. The increase of β-structural conformation suggests that HSA may form amyloid-like aggregates upon the denaturation. Full article
(This article belongs to the Section Molecular Structure and Dynamics)
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