Antipsychotics (APDs) are divided into first-generation antipsychotics (FGAs) and second-generation antipsychotics (SGAs) based on the concept that SGAs have reduced motor side effects. With this ...premise, this study examined in HeLa and other cell lines the effects of different APDs on the activation of ERK1/2 (Extracellular signal-regulated kinases) and AKT (Protein Kinase B) kinases, which may be affected in schizophrenia and bipolar disorder. Among the SGAs, Clozapine clearly resulted as the most effective drug inducing ERK1/2 phosphorylation with potency in the low micromolar range. Quetiapine and Olanzapine showed a maximal response of about 50% compared to Clozapine, while FGAs such as Haloperidol and Sulpiride did not have any relevant effect. Among FGAs, Chlorpromazine was able to partially activate ERK1/2 at 30% compared to Clozapine. Referring to AKT activation, Clozapine, Quetiapine and Olanzapine demonstrated a similar efficacy, while FGAs, besides Chlorpromazine, were incapable to obtain any particular biological response. In relation to ERK1/2 activation, we found that 5-HT
serotonin receptor antagonists Ketanserin and M100907, both partially reduced Clozapine effect. In addition, we also observed an increase of potency of Clozapine effect in HeLa transfected cells with recombinant 5-HT
receptor and in rat glioma C6 cells that express a higher amount of this receptor. This indicates that ERK1/2 stimulation induced by Clozapine could, to some extent, be mediated by 5-HT
receptor, through a novel mechanism that is called "biased agonism", even though other cellular targets are involved. This evidence may be relevant to explain the superiority of Clozapine among the APDs.
The aim of this study was to investigate the role of cyclooxygenase (COX)-1 on vascular alterations in structure, mechanics, and extracellular matrix (ECM) components induced by angiotensin (Ang) II ...in mesenteric arteries from wild-type (WT) and COX-1 knockout (COX-1(-/-)) mice.
Animals were infused with vehicle or Ang II (400 ng/kg/min, s.c.) ± SC-560 (COX-1 inhibitor), DFU (COX-2 inhibitor), or SQ-29548 (TP receptor antagonist). After 2 weeks, vessels were isolated and exposed to intraluminal pressures (3-140 mmHg, pressurized myograph) to determine mechanical properties. Angiotensin II-induced vascular hypertrophic remodelling in WT was reversed by SC-560 or SQ-29548, but unaffected by DFU. Angiotensin II increased vessel stiffness (P< 0.01), this effect being ameliorated by SC-560 or SQ-29548, but unmodified by DFU. Angiotensin II failed to modify vessel elasticity in COX-1(-/-) mice. In WT vessels, Ang II enhanced COX-1 immunostaining, induced collagen and fibronectin depositions and decreased elastin content (P< 0.01). These effects were reversed by SC-560 or SQ-29548, but unaffected by DFU. In COX-1(-/-) mice, Ang II did not affect ECM contents. In WT, Ang II increased COX-1 and decreased COX-2 expression, and enhanced the vascular release of 6-keto-PGF1α which was prevented by COX-1 blockade. Human coronary artery smooth muscle cells, incubated with Ang II, showed an increased expression of procollagen I, which was abrogated by SC-560 or SQ-29548.
Angiotensin II-induced alterations of resistance arteries in structure, mechanics, and ECM composition were prevented by COX-1 inhibition and TP receptor antagonism, indicating that Ang II-mediated vascular damage is mediated by COX-1-derived prostanoid prostacyclin, activating TP receptors.
The Polycomb gene
expression exerts a negative predictive impact on several hematological malignancies, such as acute and chronic myeloid leukemia (CML), myelofibrosis, and follicular lymphoma. As ...already demonstrated in CML,
is responsible for the resistance to the tyrosine kinase inhibitors (TKIs) in a
-independent way. Even if, it is unknown where
in CML is expressed (in progenitors or more mature cells). We decided, therefore, to evaluate if and where the BMI1 protein is located, focusing mainly on the CD34+/CD38-/CD26+ CML progenitors. To begin we measured, by flow cytometry, the proportion of CD34+/CD26+ cells in 31 bone marrow samples from 20 CML patients, at diagnosis and during treatment with imatinib. After that the bone marrow blood smears were stained with antibodies anti-CD26, BCR-ABL1, and BMI1. These smears were observed by a confocal laser microscope and a 3D reconstruction was then performed. At diagnosis, CD34+/CD26+ cells median value/μL was 0.48; this number increased from diagnosis to the third month of therapy and then reduced during treatment with imatinib. The number and behavior of the CD26+ progenitors were independent from the
expression, but they summed up what previously observed about the
expression modulation. In this work we demonstrate for the first time that in CML the BMI1 protein is co-expressed with BCR-ABL1 only in the cytoplasm of the CD26+ precursors; on the contrary, in other hematological malignancies where BMI1 is commonly expressed (follicular lymphoma, essential thrombocytemia, acute myeloid leukemia), it was not co-localized with CD26 or, obviously, with BCR-ABL1. Once translated into the clinical context, if BMI1 is a marker of stemness, our results would suggest the combination of the BMI1 inhibitors with TKIs as an interesting object of research, and, probably, as a promising way to overcome resistance in CML patients.
Cardiac myxomas are rare tumors with a heterogeneous cell population including properly neoplastic (lepidic), endothelial and smooth muscle cells. The assessment of neoplastic (
lepidic
) cell ...differentiation pattern is rather difficult using conventional light microscopy immunohistochemistry and/or whole tissue extracts for mRNA analyses. In a preliminary study, we investigated 20 formalin-fixed and paraffin-embedded cardiac myxomas by means of conventional immunohistochemistry; in 10/20 cases, cell differentiation was also analyzed by real-time RT-PCR after laser capture microdissection of the neoplastic cells, whereas calretinin and endothelial antigen CD31 immunoreactivity was localized in 4/10 cases by double immunofluorescence confocal microscopy. Gene expression analyses of α-smooth muscle actin, endothelial CD31 antigen, alpha-cardiac actin, matrix metalloprotease-2 (MMP2) and tissue inhibitor of matrix metalloprotease-1 (TIMP1) was performed on cDNA obtained from either microdissected neoplastic cells or whole tumor sections. We found very little or absent CD31 and α-Smooth Muscle Actin expression in the microdissected cells as compared to the whole tumors, whereas TIMP1 and MMP2 genes were highly expressed in both ones, greater levels being found in patients with embolic phenomena. α-Cardiac Actin was not detected. Confocal microscopy disclosed two different signals corresponding to calretinin-positive myxoma cells and to endothelial CD31-positive cells, respectively. In conclusion, the neoplastic (
lepidic
) cells showed a distinct gene expression pattern and no consistent overlapping with endothelial and smooth muscle cells or cardiac myocytes; the expression of TIMP1 and MMP2 might be related to clinical presentation; larger series studies using also systematic transcriptome analysis might be useful to confirm the present results.
Sphingosine-1-phosphate is a bioactive lipid and a signaling molecule integrated into many physiological systems such as differentiation, proliferation and migration. In mammals S1P acts through ...binding to a family of five trans-membrane, G-protein coupled receptors (S1PRs) whose complex role has not been completely elucidated. In this study we use zebrafish, in which seven
have been identified, to investigate the role of
. In mammals
is the most highly expressed S1P receptor in the developing heart and regulates vascular development, but in zebrafish the data concerning its role are contradictory. Here we show that overexpression of zebrafish
affects both vascular and cardiac development. Moreover we demonstrate that
expression is strongly repressed by miR-19a during the early phases of zebrafish development. In line with this observation and with a recent study showing that miR-19a is downregulated in a zebrafish Holt-Oram model, we now demonstrate that
is upregulated in
hearts. Next we investigated whether defects induced by
upregulation might contribute to the morphological alterations caused by Tbx5 depletion. We show that downregulation of
is able to partially rescue cardiac and fin defects induced by Tbx5 depletion. Taken together, these data support a role for
in zebrafish cardiovascular development, suggest the involvement of this receptor in the Tbx5 regulatory circuitry, and further support the crucial role of microRNAs in early phase of zebrafish development.
Starvation resistance is a life‐saving mechanism for many organisms facing food availability fluctuation in the natural environment. Different strategies have been episodically identified for some ...model organisms, the first of which was the ability to suppress metabolic rate. Among the identified strategies, the ability of planarians to shrink their body under fasting conditions and revert the process after feeding (the growth–degrowth process) represents a fascinating mechanism to face long periods of fasting. The growth–degrowth process is strictly related to the capability of planarians to continuously maintain tissue homeostasis and body proportions even in challenging conditions, thanks to the presence of a population of pluripotent stem cells. Here, we take advantage of several previous studies describing the growth–degrowth process and of recent progress in the understanding of planarian homeostasis mechanisms, to identify tissue‐selective transcriptional downregulation as a driving strategy for the development of a thrifty phenotype, and the p53 transcription factor as a player in adjusting tissue homeostasis in accordance with food availability.
Starvation resistance is a lifesaving mechanism for many organisms. The ability of planarians to shrink their body under fasting conditions represents a fascinating strategy in which the p53 transcription factor operates to adjust tissue homeostasis in accordance with food availability. In starving animals, proliferative activity is supported at the expense of tissue‐selective transcriptional downregulation and thanks to the increase in cell death.
•Planarians belonging to Dugesia japonica species were exposed to differently shaped and sized plastic microparticles via the diet.•Planarian feeding activity was not altered by the presence of ...microplastic mixed in food, irrespectively to the size, shape and chemistry.•The time of persistence of ingested microplastic was affected by size and shape; microplastic with a size below 6 μm were engulfed by enterocytes.•Chronic alimentary exposure to microplastics did not affect regeneration but induced apoptosis and growth delay.
Increasing microplastics pollution of marine and terrestrial water is a concerning issue for ecosystems and human health. Nevertheless, the interaction of microplastics with freshwater biota is still a poorly explored field. In order to achieve information concerning the uptake, distribution and effect of microplastics in planarians, Dugesia japonica specimens have been fed with mixtures of food and differently shaped and sized plastic particles. Feeding activity and food intake were non-altered by the presence of high concentrations of different types of plastic particles. However, the persistence of microplastic within the planarian body was a function of size/shape, being small spheres (<10 μm in diameter) and short fibers (14 μm large and 5/6 μm length) more persisting than larger spheres and longer fibers which were eliminated almost entirely by ejection in a few hours. Transmission electron microscopy analysis demonstrated that at least part of microplastics was phagocytized by the enterocytes. Chronic exposure to small plastic did not alter the regenerative ability but caused a significant reduction of the gut epithelium thickness and lipid content of enterocytes, together with the induction of apoptotic cell death, modulation of Djgata 4/5/6 expression and reduced growth rate. The ability of microplastic to perturb planarian homeostasis is concerning being them extremely resilient against mechanical and chemical insults and suggests possible harmful effects upon other more susceptible species in freshwater ecosystems.
Background Information
Planarians are a sound, well‐established model system for molecular studies in the field of stem cells, cell differentiation, developmental biology and translational research. ...Treated stem cell‐less planarians produced by X‐ray treatment are commonly used to study stem cell transcriptional profile and their role in planarian biological processes. X‐ray induces oxidative and DNA damage to differentiated cells, requires expensive radiation machines that are not available in most of the research centres and demand rigorous risk management and dedicated staff.
Results
We tested the use of the well‐known antimetabolite genotoxic drug 5‐fluorouracil which mainly affects proliferating cells in way to demonstrate its use in replacing X‐ray treatment. We succeeded in demonstrating ability of high doses of 5‐fluorouracil to deplete Dugesia japonica stem cells and in identifying a 5‐fluorouracil transiently resistant population of lineage committed stem cells.
Conclusions and Significance
Our results encourage the use of 5‐fluorouracil‐treated planarians as a model system for studying mechanisms of resistance to genotoxicants, planarian stem cell heterogeneity and molecular cascades of tissue aging.
Research article: We provide a further potentiation of the well‐established model system planarians. Specifically, we demonstrated the ability of 5‐fluorouracil (5FU) to produce stem cell‐less organisms and identified a sub‐population of 5FU transiently resistant stem cells (TRSC), giving insight into the complex heterogeneity of planarian neoblasts. In conclusion, we propose 5FU‐treated planarians as a valid alternative to X‐ray to study stem cell heterogeneity and tissue aging.
Ponatinib (PON), a third-generation tyrosine kinase inhibitor (TKI), has proven cardiovascular toxicity, with no known preventing agents usable to limit such side effect. Sodium-glucose cotransporter ...type 2 (SGLT2) inhibitors are a new class of glucose-lowering agents, featuring favorable cardiac and vascular effects.
We assessed the effects of the SGLT2 inhibitors empagliflozin (EMPA) and dapagliflozin (DAPA) on human aortic endothelial cells (HAECs) and underlying vasculo-protective mechanisms in an in vitro model of PON-induced endothelial toxicity.
We exposed HAECs to PON or vehicle (DMSO) in the presence or absence of EMPA (100 and 500 nmol/L) or dapagliflozin (DAPA) for 0–48 h exposure times. Compared with vehicle, incubations of HAECs with PON significantly reduced cell viability (0.56 ± 0.11 vs 0.23 ± 0.05 absorbance units, p < 0.01), increased the number of senescent cells at β-gal-assay (PON 9 ± 4 vs basal DMSO 3 ± 1 β-Gal+ cells/field, p < 0.01), decreased tubulization in Matrigel (PON PON: 6 ± 1 vs basal DMSO 12 ± 1 tubuli number/field, p < 0.05) with a non-statistically significant trend of PON to decrease the number of autophagic cells at immunofluorescence assay and flow cytometry. EMPA reverted the effects of PON on cell viability (E 500 + PON 0.24 ± 0.05 vs PON 0.56 ± 0.11 absorbance units, p < 0.01) and induced autophagy (E 500 7 ± 4.3 vs basal DMSO 2.6 ± 2.3 mean fluorescence vs PON 2.6 ± 2.4 mean fluorescence, p < 0.05). EMPA and DAPA also reversed the effects of PON on cell senescence (E 500 + PON 4 ± 1 and DAPA 100 4 ± 2 vs PON 9 ± 4 β-Gal+ cells/field, p < 0.01) and improved cell tubulization (E 500 + PON 21 ± 3 vs PON 6 ± 1 tubuli number/field, p < 0.05; DAPA 100 + PON 16 ± 2 vs PON 6 ± 1 tubuli number/field, p < 0.05).
EMPA and DAPA attenuate the vasculo-toxic effect exerted by PON by reverting endothelial cell senescence and dysfunction. These findings support the design of clinical studies exploring the vasculo-protective effects of EMPA or DAPA on PON-induced vascular toxicity.
Tau Modulates VGluT1 Expression Siano, Giacomo; Varisco, Martina; Caiazza, Maria Claudia ...
Journal of molecular biology,
02/2019, Letnik:
431, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Tau displacement from microtubules is the first step in the onset of tauopathies and is followed by toxic protein aggregation. However, other non-canonical functions of Tau might have a role in these ...pathologies. Here, we demonstrate that a small amount of Tau localizes in the nuclear compartment and accumulates in both the soluble and chromatin-bound fractions. We show that favoring Tau nuclear translocation and accumulation, by Tau overexpression or detachment from MTs, increases the expression of VGluT1, a disease-relevant gene directly involved in glutamatergic synaptic transmission. Remarkably, the P301L mutation, related to frontotemporal dementia FTDP-17, impairs this mechanism leading to a loss of function. Altogether, our results provide the demonstration of a direct physiological role of Tau on gene expression. Alterations of this mechanism may be at the basis of the onset of neurodegeneration.
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•Non-canonical functions of Tau are emerging and might have a role in tauopathies.•A small amount of Tau is associated with the chromatin in the nuclear compartment.•Impeding Tau/tubulin interaction in the cytosol favors Tau nuclear translocation.•Nuclear Tau regulates the expression of VGluT1, a disease-relevant gene.•Nuclear Tau might be a key player in the onset of tauopathy.
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