Nuclear phosphoinositides and their roles in cell biology and disease

Since the late 1980s, a growing body of evidence has documented that phosphoinositides and their metabolizing enzymes, which regulate a large variety of cellular functions both in the cytoplasm and at the plasma membrane, are present also within the nucleus, where they are involved in processes such as cell proliferation, differentiation, and survival. Remarkably, nuclear phosphoinositide metabolism operates independently from that present elsewhere in the cell. Although nuclear phosphoinositides generate second messengers such as diacylglycerol and inositol 1,4,5 trisphosphate, it is becoming increasingly clear that they may act by themselves to influence chromatin structure, gene expression, DNA repair, and mRNA export. The understanding of the biological roles played by phosphoinositides is supported by the recent acquisitions demonstrating the presence in the nuclear compartment of several proteins harboring phosphoinositide-binding domains. Some of these proteins have functional roles in RNA splicing/processing and chromatin assembly. Moreover, recent evidence shows that nuclear phospholipase Cβ1 (a key phosphoinositide metabolizing enzyme) could somehow be involved in the myelodysplastic syndrome, i.e. a hematopoietic disorder that frequently evolves into an acute leukemia. This review aims to highlight the most significant and updated findings about phosphoinositide metabolism in the nucleus under both physiological and pathological conditions.     

Management of human cytomegalovirus infection in transplantation: validation of virologic cut-offs for preemptive therapy and immunological cut-offs for protection

Human cytomegalovirus (HCMV) still causes major viral complications in the post-transplant period of both solid-organ (SO) and hematopoietic stem cell (HSC) transplant (T) recipients (R). Diagnosis of HCMV infection is mostly made by real-time PCR-based methodologies, which allow quantification of viral DNA in both blood and, if required, organ tissues or local secretions. HCMV infection/disease can be prevented by either universal prophylaxis or preemptive therapy. The latter approach has mostly been used in European Transplantation Centers upon reaching predetermined cut-off levels of viral load, predictive of high risk for HCMV disease. In our Department, these cut-offs are higher for SOTR (3x105 DNA copies/ml whole blood) and lower for HSCTR (3x104 DNA copies/ml). Antiviral therapy is continued until viral DNA disappearance from blood or tissues. However, the authentic long-term control of HCMV infection is achieved when HCMV-specific CD4+ and CD8+ T-cells are detected in blood or tissues. Proposed immunological cut-off levels conferring protection are: one HCMV-specific CD4+ and three CD8+ T-cells/ml blood for HSCTR, and 0.4 HCMV-specific T-cells/ml for both CD4+ and CD8+ in SOTR. However, anti-rejection in SOTR and anti- GvHD in HSCTR steroid therapies make patients susceptible to HCMV infection, even in the presence of protective levels of specific T-cells.     

Changes in Colloidal Properties of Oil in Water Emulsions Stabilized with Sodium Caseinate Observed by Acoustic and Electroacoustic Spectroscopy

Sodium caseinate is a commonly used emulsifier in foods, as it adsorbs on the surface of oil droplets and stabilizes them via electrostatic and steric stabilization, forming a polyelectrolyte layer at the interface. Since the protein interface is affected by varying environmental conditions such as pH, ionic strength, concentration of unadsorbed polymers, these emulsions are prone to a variety of destabilization mechanisms. The objective of the present work was to observe the destabilization of sodium caseinate stabilized oil in water emulsions using electroacoustic spectroscopy. This technique can be utilized for the characterization of concentrated colloidal systems in situ, without dilution. The electroacoustic and ultrasonic properties of soy oil in water emulsions were determined for sodium caseinate stabilized emulsions under conditions known to cause destabilization. Ultrasonic attenuation and electrophoretic mobility (ζ-potential) could clearly follow the changes occurring in the emulsion droplets, under minimal sample disruption. This is critical for these systems in a very fragile, metastable state. The emulsions were stable to the addition of high methoxyl pectin (HMP) up to 0.1% HMP. Addition of free sodium caseinate induced depletion flocculation, causing a decrease in the attenuation and electrophoretic mobility measured. The presence of HMP limited depletion interactions. Acidification of the emulsion droplets resulted in a clear sol–gel transition, as shown by a steep increase in the particle size and a decrease in attenuation. Again, destabilization was limited by HMP addition. It was concluded that ultrasonics and electroacoustics are suitable techniques to understand the details of the destabilization processes occurring to food emulsions, measured in situ.     

Identification of RC-33 as a potent and selective σ1 receptor agonist potentiating NGF-induced neurite outgrowth in PC12 cells. Part 2: g-Scale synthesis,physicochemical characterization and in vitro metabolic stability

Strong pharmacological evidences indicate that σ1 receptors are implicated in the pathophysiology of all major CNS disorders. In the last years our research group has conducted extensive studies aimed at discovering novel σ1 ligands and we recently selected (R/S)-RC-33 as a novel potent and selective σ1 receptor agonist. As continuation of our work in this field, here we report our efforts in the development of this new σ1 receptor agonist. Initially, we investigated the binding of (R) and (S) enantiomers of RC-33 to the σ1 receptor by in silico experiments. The close values of the predicted affinity of (R)-RC-33 and (S)-RC-33 for the protein evidenced the non-stereoselective binding of RC-33 to the σ1 receptor; this, in turn, supported further development and characterization of RC-33 in its racemic form. Subsequently, we set-up a scaled-up, optimized synthesis of (R/S)-RC-33 along with some compound characterization data (e.g., solubility in different media and solid state characterization by thermal analysis techniques). Finally, metabolic studies of RC-33 in different biological matrices (e.g., plasma, blood, and hepatic S9 fraction) of different species (e.g., rat, mouse, dog, and human) were performed. (R/S)-RC-33 is generally stable in all examined biological matrices, with the only exception of rat and human liver S9 fractions in the presence of NADPH. In such conditions, the compound is subjected to a relevant oxidative metabolism, with a degradation of approximately 65% in rat and 69% in human.Taken together, our results demonstrated that (R/S)-RC-33 is a highly potent, selective, metabolically stable σ1 agonist, a promising novel neuroprotective drug candidate.     

Caerulein precursor fragment (CPF) peptides from the skin secretions of Xenopus laevis and Silurana epitropicalis are potent insulin-releasing agents

Peptidomic analysis of norepinephrine-stimulated skin secretions of the tetraploid clawed frog Xenopus laevis (Pipidae) led to the identification of 10 peptides with the ability to stimulate the release of insulin from the rat BRIN-BD11 clonal β cell line. These peptides were purified to near homogeneity and structural characterization showed that they belong to the magainin (2 peptides), peptide glycine-leucine-amide (PGLa) (1 peptide), xenopsin precursor fragment (1 peptide), and caerulein precursor fragment (CPF) (6 peptides) families. CPF-1, CPF-3, CPF-5 and CPF-6 were the most potent producing a significant (P < 0.05) increase in the rate of insulin release at concentration of 0.03 nM. CPF-7 (GFGSFLGKALKAALKIGANALGGAPQQ) produced the maximum stimulation of insulin release (571 ± 30% of basal rate at 3 μM). In addition, CPF-SE1 (GFLGPLLKLGLKGVAKVIPHLIPSRQQ), previously isolated from skin secretions of the tetraploid frog Silurana epitropicalis, produced a significant (P < 0.05) increase in the rate of insulin release at 0.03 nM with a 514 ± 13% increase over basal rate at 3 μM. No CPF peptide stimulated release of the cytosolic enzyme, lactate dehydrogenase from BRIN-BD11 cells at concentrations up to 3 μM indicating that the integrity of the plasma membrane had been preserved. The mechanism of action of the CPF peptides involves, at least in part, membrane depolarization and an increase in intracellular Ca²⁺ concentration. The CPF peptides show potential for development into agents for the treatment of Type 2 diabetes.     

Mucormycosis in a Patient with Acute Myeloid Leukemia Successfully Treated with Liposomal Amphotericin B Associated with Deferasirox and Hyperbaric Oxygen

We report a 38-year-old woman presenting with febrile neutropenia, acute myeloid leukemia (AML) and invasive mucormycosis. Bone marrow aspirate was characteristic of AML minimally differentiated (WHO classification 2008). Flow cytometric immunophenotyping analysis showed blasts positive for CD7, CD33, CD34, CD71, CD117, HLA-DR, MPO, and TdT, with normal karyotype (46, XX), and the absence of the FLT3-ITD and NPM1 mutations. The patient’s management included chemotherapy with cytarabine and idarubicin, and treatment with liposomal amphotericin B, deferasirox, hyperbaric oxygen therapy, and antibiotics. Nowadays, she is in complete hematological remission, and CT images of control are normal. Invasive mucormycosis is an uncommon and severe condition, which involves diagnosis and treatment challenges. Clinical features and predisposing factors should be highlighted in order to enhance the suspicion index, contributing to early diagnosis and disease control. Our aim is to report classical features of this uncommon condition and to emphasize usual management challenges.     

Bauhinia forficata Prevents Vacuous Chewing Movements Induced by Haloperidol in Rats and Has Antioxidant Potential In Vitro

Classical antipsychotics can produce motor disturbances like tardive dyskinesia in humans and orofacial dyskinesia in rodents. These motor side effects have been associated with oxidative stress production in specific brain areas. Thus, some studies have proposed the use of natural compounds with antioxidant properties against involuntary movements induced by antipsychotics. Here, we examined the possible antioxidant activity of Bauhinia forficata (B. forficata), a plant used in folk medicine as a hypoglycemic, on brain lipid peroxidation induced by different pro-oxidants. B. forficata prevented the formation of lipid peroxidation induced by both pro-oxidants tested. However, it was effective against lipid peroxidation induced by sodium nitroprusside (IC₅₀ = 12.08 μg/mL) and Fe²⁺/EDTA (IC₅₀ = 41.19 μg/mL). Moreover, the effects of B. forficata were analyzed on an animal model of orofacial dyskinesia induced by long-term treatment with haloperidol, where rats received haloperidol each 28 days (38 mg/kg) and/or B. forficata decoction daily (2.5 g/L) for 16 weeks. Vacuous chewing movements (VCMs), locomotor and exploratory activities were evaluated. Haloperidol treatment induced VCMs, and co-treatment with B. forficata partially prevented this effect. Haloperidol reduced the locomotor and exploratory activities of animals in the open field test, which was not modified by B. forficata treatment. Our present data showed that B. forficata has antioxidant potential and partially protects against VCMs induced by haloperidol in rats. Taken together, our data suggest the protection by natural compounds against VCMs induced by haloperidol in rats.     

Brazilian Kefir-Fermented Sheep’s Milk,a Source of Antimicrobial and Antioxidant Peptides

Fermented milks are a source of bioactive peptides and may be considered as functional foods. Among these, sheep’s milk fermented with kefir has not been widely studied and its most relevant properties need to be more thoroughly characterized. This research study is set out to investigate and evaluate the antioxidant and antimicrobial properties of peptides from fermented sheep’s milk in Brazil when produced by using kefir. For this, the chemical and microbiological composition of the sheep’s milk before and after the fermentation was evaluated. The changes in the fermented milk and the peptides extracted before the fermentation and in the fermented milk during its shelf life were verified. The antimicrobial and antioxidant activities of the peptides from the fermented milk were evaluated and identified according to the literature. The physicochemical properties and mineral profile of the fermented milk were like those of fresh milk. The peptide extract presented antimicrobial activity and it was detected that 13 of the 46 peptides were able to inhibit the growth of pathogenic microorganisms. A high antioxidant activity was observed in the peptides extracted from fermented milk (3.125 mg/mL) on the 28th day of storage. Two fractions displayed efficient radical scavenging properties by DPPH and ABTS methods. At least 11 peptides distributed in the different fractions were identified by tandem mass spectrometry. This sheep’s milk fermented by Brazilian kefir grains, which has antioxidant and antimicrobial activities and probiotic microorganisms, is a good candidate for further investigation as a source for bioactive peptides. The fermentation process was thus a means by which to produce potential bioactive peptides.     

Role of the Rutin and Genistein Flavonoids in Soybean Resistance to <Emphasis Type="Italic">Piezodorus guildinii</Emphasis> (Hemiptera: Pentatomidae)

The stink bug complex includes some of the most important soybean pests worldwide. Among these insects, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae) is known for the severe damage it can cause and for its resistance to chemical management. Host plant resistance is considered as an important tool in the management of these pests. In particular, plant flavonoids, such as genistein and rutin, have been identified as compounds that might negatively affect the development of some pests; however, the effects of these compounds on some stink bug species are still unclear. We tested the resistance of soybean genotypes by evaluating the growth and survival of P. guildinii under laboratory conditions. In addition, the amounts of genistein and rutin were quantified in both infested and non-infested genotypes. The PI 274453, PI 274454, PI 227687, PI 229358, ‘IAC 100′, and ‘IAC 19′ genotypes showed antibiosis to P. guildinii. The genistein and rutin flavonoids appear to play a role in the resistance of these genotypes against P. guildinii; specifically, PI 274453, PI 274454, and ‘IAC 100′ showed induced resistance against the insect. Other defence mechanisms or flavonoids might be involved in resistance in the L1-1-01 and PI 171451 genotypes. These results help us better understand the role of flavonoids in plant defence mechanisms and might prove useful in breeding programmes aimed at developing resistant soybean plants.