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Int. J. Mol. Sci., Volume 21, Issue 4 (February-2 2020) – 376 articles

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Cover Story (view full-size image) Antimicrobial resistance (AMR) is a major health concern worldwide. The search both for more [...] Read more.
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Open AccessReview
Remodeling of Intracellular Ca2+ Homeostasis in Rat Hippocampal Neurons Aged In Vitro
Int. J. Mol. Sci. 2020, 21(4), 1549; https://doi.org/10.3390/ijms21041549 - 24 Feb 2020
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Abstract
Aging is often associated with a cognitive decline and a susceptibility to neuronal damage. It is also the most important risk factor for neurodegenerative disorders, particularly Alzheimer’s disease (AD). AD is related to an excess of neurotoxic oligomers of amyloid β peptide (Aβo); [...] Read more.
Aging is often associated with a cognitive decline and a susceptibility to neuronal damage. It is also the most important risk factor for neurodegenerative disorders, particularly Alzheimer’s disease (AD). AD is related to an excess of neurotoxic oligomers of amyloid β peptide (Aβo); however, the molecular mechanisms are still highly controversial. Intracellular Ca2+ homeostasis plays an important role in the control of neuronal activity, including neurotransmitter release, synaptic plasticity, and memory storage, as well as neuron cell death. Recent evidence indicates that long-term cultures of rat hippocampal neurons, resembling aged neurons, undergo cell death after treatment with Aβo, whereas short-term cultures, resembling young neurons, do not. These in vitro changes are associated with the remodeling of intracellular Ca2+ homeostasis with aging, thus providing a simplistic model for investigating Ca2+ remodeling in aging. In vitro aged neurons show increased resting cytosolic Ca2+ concentration, enhanced Ca2+ store content, and Ca2+ release from the endoplasmic reticulum (ER). Ca2+ transfer from the endoplasmic reticulum (ER) to mitochondria is also enhanced. Aged neurons also show decreased store-operated Ca2+ entry (SOCE), a Ca2+ entry pathway related to memory storage. At the molecular level, in vitro remodeling is associated with changes in the expression of Ca2+ channels resembling in vivo aging, including changes in N-methyl-D-aspartate NMDA receptor and inositol 1,4,5-trisphosphate (IP3) receptor isoforms, increased expression of the mitochondrial calcium uniporter (MCU), and decreased expression of Orai1/Stim1, the molecular players involved in SOCE. Additionally, Aβo treatment exacerbates most of the changes observed in aged neurons and enhances susceptibility to cell death. Conversely, the solely effect of Aβo in young neurons is to increase ER–mitochondria colocalization and enhance Ca2+ transfer from ER to mitochondria without inducing neuronal damage. We propose that cultured rat hippocampal neurons may be a useful model to investigate Ca2+ remodeling in aging and in age-related neurodegenerative disorders. Full article
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Open AccessArticle
Combined Targeting of AKT and mTOR Inhibits Proliferation of Human NF1-Associated Malignant Peripheral Nerve Sheath Tumour Cells In Vitro but not in a Xenograft Mouse Model In Vivo
Int. J. Mol. Sci. 2020, 21(4), 1548; https://doi.org/10.3390/ijms21041548 (registering DOI) - 24 Feb 2020
Viewed by 224
Abstract
Persistent signalling via the PI3K/AKT/mTOR pathway is a major driver of malignancy in NF1-associated malignant peripheral nerve sheath tumours (MPNST). Nevertheless, single targeting of this pathway is not sufficient to inhibit MPNST growth. In this report, we demonstrate that combined treatment with the [...] Read more.
Persistent signalling via the PI3K/AKT/mTOR pathway is a major driver of malignancy in NF1-associated malignant peripheral nerve sheath tumours (MPNST). Nevertheless, single targeting of this pathway is not sufficient to inhibit MPNST growth. In this report, we demonstrate that combined treatment with the allosteric pan-AKT inhibitor MK-2206 and the mTORC1/mTORC2 inhibitor AZD8055 has synergistic effects on the viability of MPNST cell lines in comparison to the treatment with each compound alone. However, when treating animals bearing experimental MPNST with the combined AKT/mTOR regime, no influence on tumour growth was observed. Further analysis of the MPNST xenograft tumours resistant to AKT/mTOR treatment revealed a reactivation of both AKT and mTOR in several tumour samples. Additional targeting of the RAS/RAF/MEK/MAPK pathway with the allosteric MEK1/2 inhibitor AZD6244 showed synergistic effects on the viability of MPNST cell lines in vitro in comparison to the dual AKT/mTOR inhibition. In summary, these data indicate that combined treatment with AKT and mTOR inhibitors is effective on MPNST cells in vitro but tumour resistance can occur rapidly in vivo by restoration of AKT/mTOR signalling. Our data further suggest that a triple treatment with inhibitors against AKT, mTORC1/2 and MEK1/2 may be a promising treatment option that should be further analysed in an experimental MPNST mouse model in vivo. Full article
(This article belongs to the Section Molecular Oncology)
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Open AccessArticle
Detection of LINE-1 hypomethylation in cfDNA of Esophageal Adenocarcinoma Patients
Int. J. Mol. Sci. 2020, 21(4), 1547; https://doi.org/10.3390/ijms21041547 - 24 Feb 2020
Viewed by 185
Abstract
DNA methylation plays an important role in cancer development. Cancer cells exhibit two types of DNA methylation alteration: site-specific hypermethylation at promoter of oncosuppressor genes and global DNA hypomethylation. This study evaluated the methylation patterns of long interspersed nuclear element (LINE-1) sequences which, [...] Read more.
DNA methylation plays an important role in cancer development. Cancer cells exhibit two types of DNA methylation alteration: site-specific hypermethylation at promoter of oncosuppressor genes and global DNA hypomethylation. This study evaluated the methylation patterns of long interspersed nuclear element (LINE-1) sequences which, due to their relative abundance in the genome, are considered a good surrogate indicator of global DNA methylation. LINE-1 methylation status was investigated in the cell-free DNA (cfDNA) of 21 patients, 19 with esophageal adenocarcinoma (EADC) and 2 with Barrett’s esophagus (BE). The two BE patients and one EADC patient were also analyzed longitudinally. Methylation status was analyzed using restriction enzymes and DNA amplification. This methodology was chosen to avoid bisulfite conversion, which we considered inadequate for cfDNA analysis. Indeed, cfDNA is characterized by poor quality and low concentration, and bisulfite conversion might worsen these conditions. Results showed that hypomethylated LINE-1 sequences are present in EADC cfDNA. Furthermore, longitudinal studies in BE suggested a correlation between methylation status of LINE-1 sequences in cfDNA and progression to EADC. In conclusion, our study indicated the feasibility of our methodological approach to detect hypomethylation events in cfDNA from EADC patients, and suggests LINE-1 methylation analysis as a new possible molecular assay to integrate into patient monitoring. Full article
(This article belongs to the Special Issue Pathophysiology of Esophageal Adenocarcinoma)
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Open AccessArticle
The Hypoxic Proteome and Metabolome of Barley (Hordeum vulgare L.) with and without Phytoglobin Priming
Int. J. Mol. Sci. 2020, 21(4), 1546; https://doi.org/10.3390/ijms21041546 (registering DOI) - 24 Feb 2020
Viewed by 261
Abstract
Overexpression of phytoglobins (formerly plant hemoglobins) increases the survival rate of plant tissues under hypoxia stress by the following two known mechanisms: (1) scavenging of nitric oxide (NO) in the phytoglobin/NO cycle and (2) mimicking ethylene priming to hypoxia when NO scavenging activates [...] Read more.
Overexpression of phytoglobins (formerly plant hemoglobins) increases the survival rate of plant tissues under hypoxia stress by the following two known mechanisms: (1) scavenging of nitric oxide (NO) in the phytoglobin/NO cycle and (2) mimicking ethylene priming to hypoxia when NO scavenging activates transcription factors that are regulated by levels of NO and O2 in the N-end rule pathway. To map the cellular and metabolic effects of hypoxia in barley (Hordeum vulgare L., cv. Golden Promise), with or without priming to hypoxia, we studied the proteome and metabolome of wild type (WT) and hemoglobin overexpressing (HO) plants in normoxia and after 24 h hypoxia (WT24, HO24). The WT plants were more susceptible to hypoxia than HO plants. The chlorophyll a + b content was lowered by 50% and biomass by 30% in WT24 compared to WT, while HO plants were unaffected. We observed an increase in ROS production during hypoxia treatment in WT seedlings that was not observed in HO seedlings. We identified and quantified 9694 proteins out of which 1107 changed significantly in abundance. Many proteins, such as ion transporters, Ca2+-signal transduction, and proteins related to protein degradation were downregulated in HO plants during hypoxia, but not in WT plants. Changes in the levels of histones indicates that chromatin restructuring plays a role in the priming of hypoxia. We also identified and quantified 1470 metabolites, of which the abundance of >500 changed significantly. In summary the data confirm known mechanisms of hypoxia priming by ethylene priming and N-end rule activation; however, the data also indicate the existence of other mechanisms for hypoxia priming in plants. Full article
(This article belongs to the Section Molecular Plant Sciences)
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Open AccessArticle
Analysis and Identification of Tumorigenic Targets of MicroRNA in Cancer Cells by Photoreactive Chemical Probes
Int. J. Mol. Sci. 2020, 21(4), 1545; https://doi.org/10.3390/ijms21041545 - 24 Feb 2020
Viewed by 170
Abstract
Photoactive RNA probes have unique advantages in the identification of microRNA (miR) targets due to their ability for efficient conjugation to the target sequences by covalent crosslinking, providing stable miR-mRNA complexes for further analysis. Here, we report a highly efficient and straightforward method [...] Read more.
Photoactive RNA probes have unique advantages in the identification of microRNA (miR) targets due to their ability for efficient conjugation to the target sequences by covalent crosslinking, providing stable miR-mRNA complexes for further analysis. Here, we report a highly efficient and straightforward method for miR target identification that is based on photo-reactive chemical probes and RNA-seq technology (denotes PCP-Seq). UV reactive probes were prepared by incorporating psoralen in the specific position of the seed sequence of miR. Cancer cells that were transfected with the miR probes were treated with UV, following the isolation of poly(A) RNA and sequencing of the transcriptome. Quantitative analysis of RNA-seq reads and subsequent validation by qPCR, dual luciferase assay as well as western blotting confirmed that PCP-Seq could highly efficiently identify multiple targets of different miRs in the lung cancer cell line, such as targets PTTG1 and PTGR1 of miR-29a and ILF2 of miR-34a. Collectively, our data showed that PCP-Seq is a robust strategy for miR targets identification, and unique in the identification of the targets that escape degradation by miRISC and maintain normal cellular level, although their translation is repressed. Full article
(This article belongs to the Section Molecular Biology)
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Open AccessReview
Emerging Roles of Interleukin-33-responsive Kidney Group 2 Innate Lymphoid Cells in Acute Kidney Injury
Int. J. Mol. Sci. 2020, 21(4), 1544; https://doi.org/10.3390/ijms21041544 (registering DOI) - 24 Feb 2020
Viewed by 146
Abstract
Interleukin (IL)-33, a member of the IL-1 family of cytokines, is involved in innate and adaptive immune responses. IL-33 triggers pleiotropic immune functions in multiple types of immune cells, which express the IL-33 receptor, ST2. Recent studies have revealed the potential applications of [...] Read more.
Interleukin (IL)-33, a member of the IL-1 family of cytokines, is involved in innate and adaptive immune responses. IL-33 triggers pleiotropic immune functions in multiple types of immune cells, which express the IL-33 receptor, ST2. Recent studies have revealed the potential applications of IL-33 for treating acute kidney injury in preclinical animal models. However, IL-33 and IL-33-responding immune cells are reported to exhibit both detrimental and beneficial roles. The IL-33-mediated immunomodulatory functions have been investigated using loss-of-function approaches, such as IL33-deficient mice, IL-33 antagonists, or administration of exogenous IL-33 recombinant protein. This review will discuss the key findings on IL-33-mediated activation of kidney resident group 2 innate lymphoid cells (ILC2s) and summarize the current understanding of the differential functions of endogenous IL-33 and exogenous IL-33 and their potential implications in treating acute kidney injury. Full article
(This article belongs to the Special Issue Renal Disease and Immunity)
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Open AccessArticle
A High Resolution Melting Analysis-Based Genotyping Toolkit for the Peach (Prunus persica) Chilling Requirement
Int. J. Mol. Sci. 2020, 21(4), 1543; https://doi.org/10.3390/ijms21041543 (registering DOI) - 24 Feb 2020
Viewed by 218
Abstract
The chilling requirement (CR) is the main factor controlling the peach floral bud break and subsequent reproductive growth. To date, several peach CR quantitative trait loci (QTLs) have been identified. To improve the accessibility and convenience of this genetic information for peach breeders, [...] Read more.
The chilling requirement (CR) is the main factor controlling the peach floral bud break and subsequent reproductive growth. To date, several peach CR quantitative trait loci (QTLs) have been identified. To improve the accessibility and convenience of this genetic information for peach breeders, the aim of this study was to establish an easy-to-use genotype screening system using peach CR molecular markers as a toolkit for marker-assisted selection. Here, we integrated 22 CR-associated markers from three published QTLs and positioned them on the Prunus persica physical map. Then, we built a PCR-based genotyping platform by using high-resolution melting (HRM) analysis with specific primers and trained this platform with 27 peach cultivars. Due to ambiguous variant calls from a commercial HRM software, we developed an R-based pipeline using principal component analysis (PCA) to accurately differentiate genotypes. Based on the PCA results, this toolkit was able to determine the genotypes at the CR-related single nucleotide polymorphisms (SNPs) in all tested peach cultivars. In this study, we showed that this HRM-PCA pipeline served as a low-cost, high-throughput, and non-gel genotyping solution. This system has great potential to accelerate CR-focused peach breeding. Full article
(This article belongs to the Section Molecular Plant Sciences)
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Open AccessArticle
Acetate and Butyrate Improve β-cell Metabolism and Mitochondrial Respiration under Oxidative Stress
Int. J. Mol. Sci. 2020, 21(4), 1542; https://doi.org/10.3390/ijms21041542 - 24 Feb 2020
Viewed by 153
Abstract
Islet dysfunction mediated by oxidative and mitochondrial stress contributes to the development of type 1 and 2 diabetes. Acetate and butyrate, produced by gut microbiota via fermentation, have been shown to protect against oxidative and mitochondrial stress in many cell types, but their [...] Read more.
Islet dysfunction mediated by oxidative and mitochondrial stress contributes to the development of type 1 and 2 diabetes. Acetate and butyrate, produced by gut microbiota via fermentation, have been shown to protect against oxidative and mitochondrial stress in many cell types, but their effect on pancreatic β-cell metabolism has not been studied. Here, human islets and the mouse insulinoma cell line MIN6 were pre-incubated with 1, 2, and 4 mM of acetate or butyrate with and without exposure to the apoptosis inducer and metabolic stressor streptozotocin (STZ). Both short-chain fatty acids (SCFAs) enhanced the viability of islets and β-cells, but the beneficial effects were more pronounced in the presence of STZ. Both SCFAs prevented STZ-induced cell apoptosis, viability reduction, mitochondrial dysfunction, and the overproduction of reactive oxygen species (ROS) and nitric oxide (NO) at a concentration of 1 mM but not at higher concentrations. These rescue effects of SCFAs were accompanied by preventing reduction of the mitochondrial fusion genes MFN, MFN2, and OPA1. In addition, elevation of the fission genes DRP1 and FIS1 during STZ exposure was prevented. Acetate showed more efficiency in enhancing metabolism and inhibiting ROS, while butyrate had less effect but was stronger in inhibiting the SCFA receptor GPR41 and NO generation. Our data suggest that SCFAs play an essential role in supporting β-cell metabolism and promoting survival under stressful conditions. It therewith provides a novel mechanism by which enhanced dietary fiber intake contributes to the reduction of Western diseases such as diabetes. Full article
(This article belongs to the Section Molecular Pathology, Diagnostics, and Therapeutics)
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Open AccessReview
Emerging Potential of Exosomes in Regenerative Medicine for Temporomandibular Joint Osteoarthritis
Int. J. Mol. Sci. 2020, 21(4), 1541; https://doi.org/10.3390/ijms21041541 - 24 Feb 2020
Viewed by 141
Abstract
Exosomes are nanosized vesicles (30–140 nm) of endocytic origin that play important roles in regenerative medicine. They are derived from cell membranes during endocytic internalization and stabilize in biological fluids such as blood and synovia. Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative [...] Read more.
Exosomes are nanosized vesicles (30–140 nm) of endocytic origin that play important roles in regenerative medicine. They are derived from cell membranes during endocytic internalization and stabilize in biological fluids such as blood and synovia. Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative disease, which, in addition to chronic pain, is characterized by progressive cartilage breakdown, condylar bone remodeling, and synovitis. However, traditional clinical treatments have limited symptom- and structure-modifying effects to restore damaged cartilage and other TMJ tissues. This is due to the limited self-healing capacity of condylar cartilage. Recently, stem-cell-derived exosomes have been studied as an alternative therapeutic approach to tissue repair and regeneration. It is known that trophic regulation of mesenchymal stem cells (MSCs) has anti-inflammatory and immunomodulatory effects under pathological conditions, and research on MSC-derived exosomes is rapidly accumulating. MSC-derived exosomes mimic the major therapeutic effects of MSCs. They affect the activity of immune effector cells and possess multilineage differentiation potential, including chondrogenic and osteogenic differentiation. Furthermore, exosomes are capable of regenerating cartilage or osseous compartments and restoring injured tissues and can treat dysfunction and pain caused by TMJ OA. In this review, we looked at the uniqueness of TMJ, the pathogenesis of TMJ OA, and the potential role of MSC-derived exosomes for TMJ cartilage and bone regeneration. Full article
(This article belongs to the Special Issue Nano/Micro-Assisted Regenerative Medicine 2.0)
Open AccessArticle
Surface Functionalization with Polyethylene Glycol and Polyethyleneimine Improves the Performance of Graphene-Based Materials for Safe and Efficient Intracellular Delivery by Laser-Induced Photoporation
Int. J. Mol. Sci. 2020, 21(4), 1540; https://doi.org/10.3390/ijms21041540 - 24 Feb 2020
Viewed by 156
Abstract
Nanoparticle mediated laser-induced photoporation is a physical cell membrane disruption approach to directly deliver extrinsic molecules into living cells, which is particularly promising in applications for both adherent and suspension cells. In this work, we explored surface modifications of graphene quantum dots (GQD) [...] Read more.
Nanoparticle mediated laser-induced photoporation is a physical cell membrane disruption approach to directly deliver extrinsic molecules into living cells, which is particularly promising in applications for both adherent and suspension cells. In this work, we explored surface modifications of graphene quantum dots (GQD) and reduced graphene oxide (rGO) with polyethylene glycol (PEG) and polyethyleneimine (PEI) to enhance colloidal stability while retaining photoporation functionality. After photoporation with FITC-dextran 10 kDa (FD10), the percentage of positive HeLa cells (81% for GQD-PEG, 74% for rGO-PEG and 90% for rGO-PEI) increased approximately two-fold compared to the bare nanomaterials. While for Jurkat suspension cells, the photoporation efficiency with polymer-modified graphene-based nanomaterial reached as high as 80%. Cell viability was >80% in all these cases. In addition, polymer functionalization proved to be beneficial for the delivery of larger macromolecules (FD70 and FD500) as well. Finally, we show that rGO is suitable for photoporation using a near-infrared laser to reach 80% FD10 positive HeLa cells at 80% cell viability. We conclude that modification of graphene-based nanoparticles with PEG and especially PEI provide better colloidal stability in cell medium, resulting in more uniform transfection and overall increased efficiency. Full article
(This article belongs to the collection Feature Papers in Materials Science)
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Open AccessReview
Neurons, Glia, Extracellular Matrix and Neurovascular Unit: A Systems Biology Approach to the Complexity of Synaptic Plasticity in Health and Disease
Int. J. Mol. Sci. 2020, 21(4), 1539; https://doi.org/10.3390/ijms21041539 - 24 Feb 2020
Viewed by 142
Abstract
The synaptic cleft has been vastly investigated in the last decades, leading to a novel and fascinating model of the functional and structural modifications linked to synaptic transmission and brain processing. The classic neurocentric model encompassing the neuronal pre- and post-synaptic terminals partly [...] Read more.
The synaptic cleft has been vastly investigated in the last decades, leading to a novel and fascinating model of the functional and structural modifications linked to synaptic transmission and brain processing. The classic neurocentric model encompassing the neuronal pre- and post-synaptic terminals partly explains the fine-tuned plastic modifications under both pathological and physiological circumstances. Recent experimental evidence has incontrovertibly added oligodendrocytes, astrocytes, and microglia as pivotal elements for synapse formation and remodeling (tripartite synapse) in both the developing and adult brain. Moreover, synaptic plasticity and its pathological counterpart (maladaptive plasticity) have shown a deep connection with other molecular elements of the extracellular matrix (ECM), once considered as a mere extracellular structural scaffold altogether with the cellular glue (i.e., glia). The ECM adds another level of complexity to the modern model of the synapse, particularly, for the long-term plasticity and circuit maintenance. This model, called tetrapartite synapse, can be further implemented by including the neurovascular unit (NVU) and the immune system. Although they were considered so far as tightly separated from the central nervous system (CNS) plasticity, at least in physiological conditions, recent evidence endorsed these elements as structural and paramount actors in synaptic plasticity. This scenario is, as far as speculations and evidence have shown, a consistent model for both adaptive and maladaptive plasticity. However, a comprehensive understanding of brain processes and circuitry complexity is still lacking. Here we propose that a better interpretation of the CNS complexity can be granted by a systems biology approach through the construction of predictive molecular models that enable to enlighten the regulatory logic of the complex molecular networks underlying brain function in health and disease, thus opening the way to more effective treatments. Full article
Open AccessReview
Synaptic GluN2A-Containing NMDA Receptors: From Physiology to Pathological Synaptic Plasticity
Int. J. Mol. Sci. 2020, 21(4), 1538; https://doi.org/10.3390/ijms21041538 - 24 Feb 2020
Viewed by 202
Abstract
N-Methyl-d-Aspartate Receptors (NMDARs) are ionotropic glutamate-gated receptors. NMDARs are tetramers composed by several homologous subunits of GluN1-, GluN2-, or GluN3-type, leading to the existence in the central nervous system of a high variety of receptor subtypes with different pharmacological and signaling [...] Read more.
N-Methyl-d-Aspartate Receptors (NMDARs) are ionotropic glutamate-gated receptors. NMDARs are tetramers composed by several homologous subunits of GluN1-, GluN2-, or GluN3-type, leading to the existence in the central nervous system of a high variety of receptor subtypes with different pharmacological and signaling properties. NMDAR subunit composition is strictly regulated during development and by activity-dependent synaptic plasticity. Given the differences between GluN2 regulatory subunits of NMDAR in several functions, here we will focus on the synaptic pool of NMDARs containing the GluN2A subunit, addressing its role in both physiology and pathological synaptic plasticity as well as the contribution in these events of different types of GluN2A-interacting proteins. Full article
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Open AccessReview
Overcoming Resistance to FLT3 Inhibitors in the Treatment of FLT3-Mutated AML
Int. J. Mol. Sci. 2020, 21(4), 1537; https://doi.org/10.3390/ijms21041537 - 24 Feb 2020
Viewed by 154
Abstract
Acute myeloid leukaemia (AML) carrying internal tandem duplication (ITD) of Fms-Like Tyrosine kinase 3 (FLT3) gene is associated with high risk of relapse and poor clinical outcome upon treatment with conventional chemotherapy. FLT3 inhibitors have been approved for the treatment of [...] Read more.
Acute myeloid leukaemia (AML) carrying internal tandem duplication (ITD) of Fms-Like Tyrosine kinase 3 (FLT3) gene is associated with high risk of relapse and poor clinical outcome upon treatment with conventional chemotherapy. FLT3 inhibitors have been approved for the treatment of this AML subtype but leukaemia relapse remains to be a major cause of treatment failure. Mechanisms of drug resistance have been proposed, including evolution of resistant leukaemic clones; adaptive cellular mechanisms and a protective leukaemic microenvironment. These models have provided important leads that may inform design of clinical trials. Clinically, FLT3 inhibitors in combination with conventional chemotherapy as induction treatment for fit patients; with low-intensity treatment as salvage treatment or induction for unfit patients as well as maintenance treatment with FLT3 inhibitors post HSCT hold promise to improve survival in this AML subtype. Full article
(This article belongs to the Special Issue Drug Resistance in Hematologic Malignancies)
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Open AccessArticle
A microRNA Expression Profile as Non-Invasive Biomarker in a Large Arrhythmogenic Cardiomyopathy Cohort
Int. J. Mol. Sci. 2020, 21(4), 1536; https://doi.org/10.3390/ijms21041536 - 24 Feb 2020
Viewed by 142
Abstract
Arrhythmogenic Cardiomyopathy (AC) is a clinically and genetically heterogeneous myocardial disease. Half of AC patients harbour private desmosomal gene variants. Although microRNAs (miRNAs) have emerged as key regulator molecules in cardiovascular diseases and their involvement, correlated to phenotypic variability or to non-invasive biomarkers, [...] Read more.
Arrhythmogenic Cardiomyopathy (AC) is a clinically and genetically heterogeneous myocardial disease. Half of AC patients harbour private desmosomal gene variants. Although microRNAs (miRNAs) have emerged as key regulator molecules in cardiovascular diseases and their involvement, correlated to phenotypic variability or to non-invasive biomarkers, has been advanced also in AC, no data are available in larger disease cohorts. Here, we propose the largest AC cohort unbiased by technical and biological factors. MiRNA profiling on nine right ventricular tissue, nine blood samples of AC patients, and four controls highlighted 10 differentially expressed miRNAs in common. Six of these were validated in a 90-AC patient cohort independent from genetic status: miR-122-5p, miR-133a-3p, miR-133b, miR-142-3p, miR-182-5p, and miR-183-5p. This six-miRNA set showed high discriminatory diagnostic power in AC patients when compared to controls (AUC-0.995), non-affected family members of AC probands carrying a desmosomal pathogenic variant (AUC-0.825), and other cardiomyopathy groups (Hypertrophic Cardiomyopathy: AUC-0.804, Dilated Cardiomyopathy: AUC-0.917, Brugada Syndrome: AUC-0.981, myocarditis: AUC-0.978). AC-related signalling pathways were targeted by this set of miRNAs. A unique set of six-miRNAs was found both in heart-tissue and blood samples of AC probands, supporting its involvement in disease pathogenesis and its possible role as a non-invasive AC diagnostic biomarker. Full article
(This article belongs to the Special Issue Genetics and Molecular Pathogenesis of Non-Ischemic Cardiomyopathies)
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Open AccessReview
Sex and Gender Aspects for Patient Stratification in Allergy Prevention and Treatment
Int. J. Mol. Sci. 2020, 21(4), 1535; https://doi.org/10.3390/ijms21041535 - 24 Feb 2020
Viewed by 285
Abstract
Allergies are rapidly worsening in recent decades, representing the most common immunological diseases. The mechanism of disorders such as asthma, rhinocongiuntivitis, urticaria, atopic dermatitis, food and drug allergies, and anaphylaxis still remain unclear and consequently treatments is mostly still symptomatic and aspecific while [...] Read more.
Allergies are rapidly worsening in recent decades, representing the most common immunological diseases. The mechanism of disorders such as asthma, rhinocongiuntivitis, urticaria, atopic dermatitis, food and drug allergies, and anaphylaxis still remain unclear and consequently treatments is mostly still symptomatic and aspecific while developments of new therapies are limited. A growing amount of data in the literature shows us how the prevalence of allergic diseases is different in both sexes and its changes over the course of life. Genes, hormones, environmental and immunological factors affect sex disparities associated with the development and control of allergic diseases, while they more rarely are considered and reported regarding their differences related to social, psychological, cultural, economic, and employment aspects. This review describes the available knowledge on the role of sex and gender in allergies in an attempt to improve the indispensable gender perspective whose potential is still underestimated while it represents a significant turning point in research and the clinic. It will offer insights to stimulate exploration of the many aspects still unknown in this relationship that could ameliorate the preventive, diagnostic, and therapeutic strategies in allergic diseases. Full article
(This article belongs to the Special Issue Gender Medicine: Pharmacogenetics and Personalised Medicine)
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Open AccessReview
Micronucleus Assay: The State of Art, and Future Directions
Int. J. Mol. Sci. 2020, 21(4), 1534; https://doi.org/10.3390/ijms21041534 - 24 Feb 2020
Viewed by 154
Abstract
During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among [...] Read more.
During almost 40 years of use, the micronucleus assay (MN) has become one of the most popular methods to assess genotoxicity of different chemical and physical factors, including ionizing radiation-induced DNA damage. In this minireview, we focus on the position of MN among the other genotoxicity tests, its usefulness in different applications and visibility by international organizations, such as International Atomic Energy Agency, Organization for Economic Co-operation and Development and International Organization for Standardization. In addition, the mechanism of micronuclei formation is discussed. Finally, foreseen directions of the MN development are pointed, such as automation, buccal cells MN and chromothripsis phenomenon. Full article
(This article belongs to the Special Issue Radiation-Induced Damage to DNA)
Open AccessArticle
Strategy of Hepatic Metabolic Defects Induced by beclin1 Heterozygosity in Adult Zebrafish
Int. J. Mol. Sci. 2020, 21(4), 1533; https://doi.org/10.3390/ijms21041533 - 24 Feb 2020
Viewed by 144
Abstract
Hepatic disorders have been increasing in recent years because of high carbohydrate diets. Hepatocytes depend mainly on the basal autophagy to maintain hepatic glucose/lipid homeostasis in mammals. However, the regulatory mechanisms of autophagy in hepatic energy metabolism are still unknown in fish species. [...] Read more.
Hepatic disorders have been increasing in recent years because of high carbohydrate diets. Hepatocytes depend mainly on the basal autophagy to maintain hepatic glucose/lipid homeostasis in mammals. However, the regulatory mechanisms of autophagy in hepatic energy metabolism are still unknown in fish species. Accordingly, mutant zebrafish lines of autophagy-related genes beclin1 and atg7 were generated by CRISPR/Cas9 gene-editing technology. Interestingly, unlike atg7+/−, male beclin1+/− zebrafish displayed liver defects in the morphology and histology, including abnormal hepatocyte proliferation, hemorrhagic and inflammatory phenotypes. A significant decrease in hepatocyte glycogen and an increase in hepatocyte lipids were detected in the histological assay that coincidence with the hepatic gene expression. Meanwhile, loss of heterozygosity for beclin1 creates a suitable microenvironment for hepatic tumorigenesis via phosphorylation of Akt kinase, which in turn affects liver autophagy. The reduction in autophagy activity in male beclin1+/− liver leads to a disturbance in the glucose/lipid metabolism and negatively regulates apoptosis accompanied by the induction of cellular proliferation and acute inflammatory response. Our findings highlight an important role of beclin1 in zebrafish liver development and energy metabolism, suggesting the crucial role of autophagy in maintaining homeostasis of the nutrient metabolism in fish species. Full article
(This article belongs to the Section Molecular Genetics and Genomics)
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Endothelial Nitric Oxide Mediates the Anti-Atherosclerotic Action of Torenia concolor Lindley var. Formosama Yamazaki
Int. J. Mol. Sci. 2020, 21(4), 1532; https://doi.org/10.3390/ijms21041532 - 24 Feb 2020
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Abstract
Torenia concolor Lindley var. formosama Yamazaki ethanolic extract (TCEE) is reported to have anti-inflammatory and anti-obesity properties. However, the effects of TCEE and its underlying mechanisms in the activation of endothelial nitric oxide synthase (eNOS) have not yet been investigated. Increasing the endothelium-derived [...] Read more.
Torenia concolor Lindley var. formosama Yamazaki ethanolic extract (TCEE) is reported to have anti-inflammatory and anti-obesity properties. However, the effects of TCEE and its underlying mechanisms in the activation of endothelial nitric oxide synthase (eNOS) have not yet been investigated. Increasing the endothelium-derived nitric oxide (NO) production has been known to be beneficial against the development of cardiovascular diseases. In this study, we investigated the effect of TCEE on eNOS activation and NO-related endothelial function and inflammation by using an in vitro system. In endothelial cells (ECs), TCEE increased NO production in a concentration-dependent manner without affecting the expression of eNOS. In addition, TCEE increased the phosphorylation of eNOS at serine 635 residue (Ser635) and Ser1179, Akt at Ser473, calmodulin kinase II (CaMKII) at threonine residue 286 (Thr286), and AMP-activated protein kinase (AMPK) at Thr172. Moreover, TCEE-induced NO production, and EC proliferation, migration, and tube formation were diminished by pretreatment with LY294002 (an Akt inhibitor), KN62 (a CaMKII inhibitor), and compound C (an AMPK inhibitor). Additionally, TCEE attenuated the tumor necrosis factor-α-induced inflammatory response as evidenced by the expression of adhesion molecules in ECs and monocyte adhesion onto ECs. These inflammatory effects of TCEE were abolished by L-NG-nitroarginine methyl ester (an NOS inhibitor). Moreover, chronic treatment with TCEE attenuated hyperlipidemia, systemic and aortic inflammatory response, and the atherosclerotic lesions in apolipoprotein E-deficient mice. Collectively, our findings suggest that TCEE may confer protection from atherosclerosis by preventing endothelial dysfunction. Full article
(This article belongs to the Special Issue Nitric Oxide Synthases: Regulation and Function 2.0)
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Open AccessArticle
Tissue Distribution of the Readthrough Isoform of AQP4 Reveals a Dual Role of AQP4ex Limited to CNS
Int. J. Mol. Sci. 2020, 21(4), 1531; https://doi.org/10.3390/ijms21041531 - 24 Feb 2020
Viewed by 169
Abstract
Translational readthrough (TRT) of aquaporin-4 (AQP4) has remarkably expanded the importance of this new post-transcriptional mechanism, as well as the regulation potential of AQP4. The TRT isoform of AQP4, named AQP4ex, is central for both AQP4 polarization and water channel activity in the [...] Read more.
Translational readthrough (TRT) of aquaporin-4 (AQP4) has remarkably expanded the importance of this new post-transcriptional mechanism, as well as the regulation potential of AQP4. The TRT isoform of AQP4, named AQP4ex, is central for both AQP4 polarization and water channel activity in the central nervous system (CNS). Here we evaluate the relevance of the TRT mechanism by analyzing whether AQP4ex is also expressed in peripheral tissues and whether the expression of AQP4ex is necessary for its polarized expression as it occurs in perivascular astrocyte processes. To this purpose, AQP4ex null mice were used, and analysis was performed by immunolocalization and immunoblot. The results demonstrate that AQP4ex is expressed in kidney, stomach, trachea and skeletal muscle with the same localization pattern as the canonical AQP4 isoforms. AQP4ex protein levels vary from 6% to about 13% of the total AQP4 protein levels in peripheral tissues. Immunogold electron microscopy experiments demonstrated the localization of AQP4ex at the astrocytic endfeet, and experiments conducted on AQP4ex null mice CNS confirmed that the expression of AQP4ex is necessary for anchoring of the perivascular AQP4. Without the readthrough isoform, AQP4 assemblies are mis-localized, being uniformly distributed on the astrocyte processes facing the neuropile. No alteration of AQP4 polarization was found in AQP4ex null kidney, stomach, trachea or skeletal muscle, suggesting that AQP4ex does not have a role for proper membrane localization of AQP4 in peripheral tissues. We conclude that a dual role for AQP4ex is limited to the CNS. Full article
(This article belongs to the Special Issue Aquaporins: Water Channels Essential for Living Organisms 3.0)
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Open AccessArticle
An Engineered Gene Nanovehicle Developed for Smart Gene Therapy to Selectively Inhibit Smooth Muscle Cells: An In Vitro Study
Int. J. Mol. Sci. 2020, 21(4), 1530; https://doi.org/10.3390/ijms21041530 - 24 Feb 2020
Viewed by 147
Abstract
In-stent restenosis is a serious concern for patients treated through the stenting procedure, although this can be solved using drug-eluting stents and/or drug-eluting balloon catheters. However, the chemical agents released from the drug-eluting layer for inhibiting smooth muscle cell (SMC) migration are inevitably [...] Read more.
In-stent restenosis is a serious concern for patients treated through the stenting procedure, although this can be solved using drug-eluting stents and/or drug-eluting balloon catheters. However, the chemical agents released from the drug-eluting layer for inhibiting smooth muscle cell (SMC) migration are inevitably associated with damage to vascular endothelial cell (ECs). The present in vitro study used a distinct strategy, in which a smart gene (phEGR1-PKCδ, an engineered plasmid consists of an SMC-specific promoter (human early growth response 1, hEGR1 promoter) ligated with a gene encoding apoptosis-inducing protein (protein kinase C-delta, PKCδ) was incorporated into a novel gene vehicle (Au cluster-incorporated polyethylenimine/carboxymethyl hexanoyl chitosan, PEI-Au/CHC) to form the PEI-Au/CHC/phEGR1-PKCδ complex, which was proposed for the selective inhibition of SMC proliferation. It was found that the cell viability of SMCs receiving the PEI-Au/CHC/phEGR1-PKCδ complex under simulated inflammation conditions was significantly lower than that of the ECs receiving the same treatment. In addition, the PEI-Au/CHC/phEGR1-PKCδ complex did not demonstrate an inhibitory effect on EC proliferation and migration under simulated inflammation conditions. Finally, the PEI-Au/CHC/phEGR1-PKCδ complexes coated onto a balloon catheter used in percutaneous transluminal coronary angioplasty (PTCA) could be transferred to both the ECs and the SMC layer of Sprague Dawley (SD) rat aortas ex vivo. These preliminary in vitro results suggest that the newly developed approach proposed in the present study might be a potential treatment for reducing the incidence rate of in-stent restenosis and late thrombosis in the future. Full article
(This article belongs to the Special Issue Bio-Engineering and Nano-Medicine)
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Open AccessArticle
Purification of Boron Nitride Nanotubes Enhances Biological Application Properties
Int. J. Mol. Sci. 2020, 21(4), 1529; https://doi.org/10.3390/ijms21041529 - 24 Feb 2020
Viewed by 144
Abstract
Commercially available boron nitride nanotubes (BNNTs) and their purified form (pBNNTs) were dispersed in aqueous solutions with various dispersants, and their cytotoxicity and drug encapsulation capacity were monitored. Our data suggest that pBNNTs showed an average increase in dispersibility of 37.3% in aqueous [...] Read more.
Commercially available boron nitride nanotubes (BNNTs) and their purified form (pBNNTs) were dispersed in aqueous solutions with various dispersants, and their cytotoxicity and drug encapsulation capacity were monitored. Our data suggest that pBNNTs showed an average increase in dispersibility of 37.3% in aqueous solution in the presence of 10 different dispersants. In addition, 100 μg of pBNNTs induced an average decrease in cytotoxicity of 27.4% compared to same amount of BNNTs in normal cell lines. The same amount of pBNNTs can encapsulate 10.4-fold more drug (camptothecin) compared to BNNTs. These data suggest that the purification of BNNTs improves several of their properties, which can be applied to biological experiments and are thus essential in the biological application of BNNTs. Full article
(This article belongs to the Special Issue Cell-Biomaterial Interaction 2019)
Open AccessArticle
PbMYB120 Negatively Regulates Anthocyanin Accumulation in Pear
Int. J. Mol. Sci. 2020, 21(4), 1528; https://doi.org/10.3390/ijms21041528 - 24 Feb 2020
Viewed by 151
Abstract
Subgroup 4 R2R3 MYBs play vital roles in the regulation of anthocyanin biosynthesis. However, there is limited knowledge regarding the functions of MYB repressors in pear (Pyrus × bretschneideri). Here, PbMYB120 was identified as a potential regulator of anthocyanin biosynthesis. A [...] Read more.
Subgroup 4 R2R3 MYBs play vital roles in the regulation of anthocyanin biosynthesis. However, there is limited knowledge regarding the functions of MYB repressors in pear (Pyrus × bretschneideri). Here, PbMYB120 was identified as a potential regulator of anthocyanin biosynthesis. A phylogenetic analysis revealed that PbMYB120 was clustered into the FaMYB1-like clade of the subgroup 4 R2R3 MYBs. PbMYB120 was expressed higher in red peels than in green peels in five pear cultivars. PbMYB120 expression was positively correlated with anthocyanin accumulation. However, the transient overexpression of PbMYB120 led to the inhibition of anthocyanin accumulation and PbUFGT1 expression. Promoter binding and activation assays indicated that PbMYB120 binds to the promoter of PbUFGT1 and represses the promoter’s activity. Thus, the inhibition of anthocyanin accumulation by PbMYB120 may be correlated with the repression of PbUFGT1. Furthermore, during anthocyanin induction, the expression levels of anthocyanin activators and PbMYB120 were upregulated. This study demonstrated that PbMYB120 was highly expressed in pear tissues having higher anthocyanin accumulations but acted as a repressor in the regulation of anthocyanin accumulation. PbMYB120 may work coordinately with anthocyanin activators and serve as a balancer of anthocyanin accumulation. Full article
(This article belongs to the Section Molecular Plant Sciences)
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Open AccessEditorial
Adaptation to Hypoxia: A Chimera?
Int. J. Mol. Sci. 2020, 21(4), 1527; https://doi.org/10.3390/ijms21041527 - 24 Feb 2020
Viewed by 133
Abstract
The Chimera was, according to Greek mythology, a monstrous fire-breathing hybrid creature of Lycia in Asia Minor, composed of the parts of more than one animal [...] Full article
(This article belongs to the Special Issue Adaptation to Hypoxia: A Chimera?)
Open AccessArticle
The Administration of 4-Hexylresorcinol Accelerates Orthodontic Tooth Movement and Increases the Expression Level of Bone Turnover Markers in Ovariectomized Rats
Int. J. Mol. Sci. 2020, 21(4), 1526; https://doi.org/10.3390/ijms21041526 - 24 Feb 2020
Viewed by 173
Abstract
Surgical methods for accelerating orthodontic tooth movement are limited by possible damage to the tooth root and patient discomfort. 4-Hexylresorcinol (4HR) has been shown to increase bone remodeling and may potentially facilitate tooth movement. This study investigated the (1) effect of 4HR administration [...] Read more.
Surgical methods for accelerating orthodontic tooth movement are limited by possible damage to the tooth root and patient discomfort. 4-Hexylresorcinol (4HR) has been shown to increase bone remodeling and may potentially facilitate tooth movement. This study investigated the (1) effect of 4HR administration on osteoblast-like cells and (2) effect of 4HR administration on tooth movement in ovariectomized rats. Saos-2 cells were treated with either 4HR or solvent (control). Protein expression levels were investigated 2, 8, and 24 h after treatment. Thirty ovariectomized Sprague-Dawley rats were divided into two experimental groups (A and B) and one control group. After installation of an orthodontic tooth movement device, groups A and B received subcutaneous weekly injections of 4HR (1.28 and 128 mg/kg). Micro-computerized tomography and histological analyses were performed after 2 weeks of tooth movement. The application of 4HR elevated expression of osteogenic markers in Saos-2 cells. Movement of the first molars was significantly greater in rats administered 4HR. Furthermore, the expression of bone morphogenic protein-2, receptor activator of nuclear factor kappa-B ligand, osteocalcin, and tartrate-resistant acid phosphatase were increased after 4HR administration. 4HR application demonstrated increased expression of osteogenic markers in Saos-2 cells and accelerated orthodontic tooth movement in rats. Full article
(This article belongs to the Section Molecular Pathology, Diagnostics, and Therapeutics)
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Open AccessReview
Molecular Mechanisms: Connections between Nonalcoholic Fatty Liver Disease, Steatohepatitis and Hepatocellular Carcinoma
Int. J. Mol. Sci. 2020, 21(4), 1525; https://doi.org/10.3390/ijms21041525 - 23 Feb 2020
Viewed by 254
Abstract
Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), causes hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The patatin-like phospholipase-3 (PNPLA3) I148M sequence variant is one of the strongest genetic determinants of NAFLD/NASH. PNPLA3 is an independent risk factor for HCC among patients [...] Read more.
Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), causes hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The patatin-like phospholipase-3 (PNPLA3) I148M sequence variant is one of the strongest genetic determinants of NAFLD/NASH. PNPLA3 is an independent risk factor for HCC among patients with NASH. The obesity epidemic is closely associated with the rising prevalence and severity of NAFLD/NASH. Furthermore, metabolic syndrome exacerbates the course of NAFLD/NASH. These factors are able to induce apoptosis and activate immune and inflammatory pathways, resulting in the development of hepatic fibrosis and NASH, leading to progression toward HCC. Small intestinal bacterial overgrowth (SIBO), destruction of the intestinal mucosa barrier function and a high-fat diet all seem to exacerbate the development of hepatic fibrosis and NASH, leading to HCC in patients with NAFLD/NASH. Thus, the intestinal microbiota may play a role in the development of NAFLD/NASH. In this review, we describe recent advances in our knowledge of the molecular mechanisms contributing to the development of hepatic fibrosis and HCC in patients with NAFLD/NASH. Full article
Open AccessReview
Review of Three-Dimensional Liquid Chromatography Platforms for Bottom-Up Proteomics
Int. J. Mol. Sci. 2020, 21(4), 1524; https://doi.org/10.3390/ijms21041524 - 23 Feb 2020
Viewed by 238
Abstract
Proteomics is a large-scale study of proteins, aiming at the description and characterization of all expressed proteins in biological systems. The expressed proteins are typically highly complex and large in abundance range. To fulfill high accuracy and sensitivity of proteome analysis, the hybrid [...] Read more.
Proteomics is a large-scale study of proteins, aiming at the description and characterization of all expressed proteins in biological systems. The expressed proteins are typically highly complex and large in abundance range. To fulfill high accuracy and sensitivity of proteome analysis, the hybrid platforms of multidimensional (MD) separations and mass spectrometry have provided the most powerful solution. Multidimensional separations provide enhanced peak capacity and reduce sample complexity, which enables mass spectrometry to analyze more proteins with high sensitivity. Although two-dimensional (2D) separations have been widely used since the early period of proteomics, three-dimensional (3D) separation was barely used by low reproducibility of separation, increased analysis time in mass spectrometry. With developments of novel microscale techniques such as nano-UPLC and improvements of mass spectrometry, the 3D separation becomes a reliable and practical selection. This review summarizes existing offline and online 3D-LC platforms developed for proteomics and their applications. In detail, setups and implementation of those systems as well as their advances are outlined. The performance of those platforms is also discussed and compared with the state-of-the-art 2D-LC. In addition, we provide some perspectives on the future developments and applications of 3D-LC in proteomics. Full article
(This article belongs to the collection Advances in Proteomic Research)
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Open AccessArticle
Discovery of Small-Molecule Activators for Glucose-6-Phosphate Dehydrogenase (G6PD) Using Machine Learning Approaches
Int. J. Mol. Sci. 2020, 21(4), 1523; https://doi.org/10.3390/ijms21041523 - 23 Feb 2020
Viewed by 240
Abstract
Glucose-6-Phosphate Dehydrogenase (G6PD) is a ubiquitous cytoplasmic enzyme converting glucose-6-phosphate into 6-phosphogluconate in the pentose phosphate pathway (PPP). The G6PD deficiency renders the inability to regenerate glutathione due to lack of Nicotine Adenosine Dinucleotide Phosphate (NADPH) and produces stress conditions that can cause [...] Read more.
Glucose-6-Phosphate Dehydrogenase (G6PD) is a ubiquitous cytoplasmic enzyme converting glucose-6-phosphate into 6-phosphogluconate in the pentose phosphate pathway (PPP). The G6PD deficiency renders the inability to regenerate glutathione due to lack of Nicotine Adenosine Dinucleotide Phosphate (NADPH) and produces stress conditions that can cause oxidative injury to photoreceptors, retinal cells, and blood barrier function. In this study, we constructed pharmacophore-based models based on the complex of G6PD with compound AG1 (G6PD activator) followed by virtual screening. Fifty-three hit molecules were mapped with core pharmacophore features. We performed molecular descriptor calculation, clustering, and principal component analysis (PCA) to pharmacophore hit molecules and further applied statistical machine learning methods. Optimal performance of pharmacophore modeling and machine learning approaches classified the 53 hits as drug-like (18) and nondrug-like (35) compounds. The drug-like compounds further evaluated our established cheminformatics pipeline (molecular docking and in silico ADMET (absorption, distribution, metabolism, excretion and toxicity) analysis). Finally, five lead molecules with different scaffolds were selected by binding energies and in silico ADMET properties. This study proposes that the combination of machine learning methods with traditional structure-based virtual screening can effectively strengthen the ability to find potential G6PD activators used for G6PD deficiency diseases. Moreover, these compounds can be considered as safe agents for further validation studies at the cell level, animal model, and even clinic setting. Full article
(This article belongs to the Section Molecular Informatics)
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Open AccessCommunication
Serum Levels and Removal by Haemodialysis and Haemodiafiltration of Tryptophan-Derived Uremic Toxins in ESKD Patients
Int. J. Mol. Sci. 2020, 21(4), 1522; https://doi.org/10.3390/ijms21041522 - 23 Feb 2020
Viewed by 191
Abstract
Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid [...] Read more.
Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD. Blood and spent dialysate samples obtained during dialysis were analysed with high-performance liquid chromatography to assess uremic solutes, their reduction ratio (RR) and total removed solute (TRS). Mean free serum tryptophan and IS concentrations increased, and concentration of IAA decreased over pre-dialysis levels (67%, 49%, −0.8%, respectively) during the first hour of dialysis. While mean serum total urea, IS and IAA concentrations decreased during dialysis (−72%, −39%, −43%, respectively), serum tryptophan levels increased, resulting in negative RR (−8%) towards the end of the dialysis session (p < 0.001), despite remarkable Trp losses in dialysate. RR and TRS values based on serum (total, free) and dialysate solute concentrations were lower for conventional low-flux dialysis (p < 0.001). High-efficiency haemodiafiltration resulted in 80% higher Trp losses than conventional low-flux dialysis, despite similar neutral Trp RR values. In conclusion, serum Trp concentrations and RR behave differently from uremic solutes IS, IAA and urea and Trp RR did not reflect dialysis Trp losses. Conventional low-flux dialysis may not adequately clear Trp-related uremic toxins while high efficiency haemodiafiltration increased Trp losses. Full article
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Open AccessArticle
Characterization of a Novel Rice Dynamic Narrow-Rolled Leaf Mutant with Deficiencies in Aromatic Amino Acids
Int. J. Mol. Sci. 2020, 21(4), 1521; https://doi.org/10.3390/ijms21041521 - 23 Feb 2020
Viewed by 193
Abstract
The leaf blade is the main photosynthetic organ and its morphology is related to light energy capture and conversion efficiency. We isolated a novel rice Dynamic Narrow-Rolled Leaf 1 (dnrl1) mutant showing reduced width of leaf blades, rolled leaves and lower [...] Read more.
The leaf blade is the main photosynthetic organ and its morphology is related to light energy capture and conversion efficiency. We isolated a novel rice Dynamic Narrow-Rolled Leaf 1 (dnrl1) mutant showing reduced width of leaf blades, rolled leaves and lower chlorophyll content. The narrow-rolled leaf phenotype resulted from the reduced number of small longitudinal veins per leaf, smaller size and irregular arrangement of bulliform cells compared with the wild-type. DNRL1 was mapped to chromosome 7 and encoded a putative 3-deoxy-7-phosphoheptulonate synthase (DAHPS) which catalyzes the conversion of phosphoenolpyruvate and D-erythrose 4-phosphate to DAHP and phosphate. Sequence analysis revealed that a single base substitution (T–A) was detected in dnrl1, leading to a single amino acid change (L376H) in the coding protein. The mutation led to a lower expression level of DNRL1 as well as the lower activity of DAHPS in the mutant compared with the wild type. Genetic complementation and over-expression of DNRL1 could rescue the narrow-rolled phenotype. DNRL1 was constitutively expressed in all tested organs and exhibited different expression patterns from other narrow-rolled leaf genes. DNRL1-GFP located to chloroplasts. The lower level of chlorophyll in dnrl1 was associated with the downregulation of the genes responsible for chlorophyll biosynthesis and photosynthesis. Furthermore, dnrl1 showed significantly reduced levels of aromatic amino acids including Trp, Phe and Tyr. We conclude that OsDAHPS, encoded by DNRL1, plays a critical role in leaf morphogenesis by mediating the biosynthesis of amino acids in rice. Full article
(This article belongs to the Section Molecular Plant Sciences)
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Open AccessArticle
Augmenting Vacuolar H+-ATPase Function Prevents Cardiomyocytes from Lipid-Overload Induced Dysfunction
Int. J. Mol. Sci. 2020, 21(4), 1520; https://doi.org/10.3390/ijms21041520 - 23 Feb 2020
Viewed by 216
Abstract
The diabetic heart is characterized by a shift in substrate utilization from glucose to lipids, which may ultimately lead to contractile dysfunction. This substrate shift is facilitated by increased translocation of lipid transporter CD36 (SR-B2) from endosomes to the sarcolemma resulting in increased [...] Read more.
The diabetic heart is characterized by a shift in substrate utilization from glucose to lipids, which may ultimately lead to contractile dysfunction. This substrate shift is facilitated by increased translocation of lipid transporter CD36 (SR-B2) from endosomes to the sarcolemma resulting in increased lipid uptake. We previously showed that endosomal retention of CD36 is dependent on the proper functioning of vacuolar H+-ATPase (v-ATPase). Excess lipids trigger CD36 translocation through inhibition of v-ATPase function. Conversely, in yeast, glucose availability is known to enhance v-ATPase function, allowing us to hypothesize that glucose availability, via v-ATPase, may internalize CD36 and restore contractile function in lipid-overloaded cardiomyocytes. Increased glucose availability was achieved through (a) high glucose (25 mM) addition to the culture medium or (b) adenoviral overexpression of protein kinase-D1 (a kinase mediating GLUT4 translocation). In HL-1 cardiomyocytes, adult rat and human cardiomyocytes cultured under high-lipid conditions, each treatment stimulated v-ATPase re-assembly, endosomal acidification, endosomal CD36 retention and prevented myocellular lipid accumulation. Additionally, these treatments preserved insulin-stimulated GLUT4 translocation and glucose uptake as well as contractile force. The present findings reveal v-ATPase functions as a key regulator of cardiomyocyte substrate preference and as a novel potential treatment approach for the diabetic heart. Full article
(This article belongs to the collection Feature Papers in Molecular Biology)
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