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Cellular and Molecular Life Sciences :... May 2024N-methyl-D-aspartate receptors (NMDARs emerging from GRIN genes) are tetrameric receptors that form diverse channel compositions in neurons, typically consisting of two...
N-methyl-D-aspartate receptors (NMDARs emerging from GRIN genes) are tetrameric receptors that form diverse channel compositions in neurons, typically consisting of two GluN1 subunits combined with two GluN2(A-D) subunits. During prenatal stages, the predominant channels are di-heteromers with two GluN1 and two GluN2B subunits due to the high abundance of GluN2B subunits. Postnatally, the expression of GluN2A subunits increases, giving rise to additional subtypes, including GluN2A-containing di-heteromers and tri-heteromers with GluN1, GluN2A, and GluN2B subunits. The latter emerge as the major receptor subtype at mature synapses in the hippocampus. Despite extensive research on purely di-heteromeric receptors containing two identical GRIN variants, the impact of a single variant on the function of other channel forms, notably tri-heteromers, is lagging. In this study, we systematically investigated the effects of two de novo GRIN2B variants (G689C and G689S) in pure, mixed di- and tri-heteromers. Our findings reveal that incorporating a single variant in mixed di-heteromers or tri-heteromers exerts a dominant negative effect on glutamate potency, although 'mixed' channels show improved potency compared to pure variant-containing di-heteromers. We show that a single variant within a receptor complex does not impair the response of all receptor subtypes to the positive allosteric modulator pregnenolone-sulfate (PS), whereas spermine completely fails to potentiate tri-heteromers containing GluN2A and -2B-subunits. We examined PS on primary cultured hippocampal neurons transfected with the variants, and observed a positive impact over current amplitudes and synaptic activity. Together, our study supports previous observations showing that mixed di-heteromers exhibit improved glutamate potency and extend these findings towards the exploration of the effect of Loss-of-Function variants over tri-heteromers. Notably, we provide an initial and crucial demonstration of the beneficial effects of GRIN2B-relevant potentiators on tri-heteromers. Our results underscore the significance of studying how different variants affect distinct receptor subtypes, as these effects cannot be inferred solely from observations made on pure di-heteromers. Overall, this study contributes to ongoing efforts to understand the pathophysiology of GRINopathies and provides insights into potential treatment strategies.
Topics: Receptors, N-Methyl-D-Aspartate; Pregnenolone; Humans; Animals; HEK293 Cells; Hippocampus; Loss of Function Mutation; Protein Multimerization; Neurons; Protein Subunits
PubMed: 38795169
DOI: 10.1007/s00018-024-05243-x -
International Journal of Molecular... May 2024This review describes a 50-year-long research study on the characteristics of L. tuber dormancy, its natural release and programmed cell death (PCD), as well as on the... (Review)
Review
This review describes a 50-year-long research study on the characteristics of L. tuber dormancy, its natural release and programmed cell death (PCD), as well as on the ability to change the PCD so as to return the tuber to a life program. The experimentation on the tuber over the years is due to its particular properties of being naturally deficient in polyamines (PAs) during dormancy and of immediately reacting to transplants by growing and synthesizing PAs. This review summarizes the research conducted in a unicum body. As in nature, the tuber tissue has to furnish its storage substances to grow vegetative buds, whereby its destiny is PCD. The review's main objective concerns data on PCD, the link with free and conjugated PAs and their capacity to switch the destiny of the tuber from a program of death to one of new life. PCD reversibility is an important biological challenge that is verified here but not reported in other experimental models. Important aspects of PA features are their capacity to change the cell functions from storage to meristematic ones and their involvement in amitosis and differentiation. Other roles reported here have also been confirmed in other plants. PAs exert multiple diverse roles, suggesting that they are not simply growth substances, as also further described in other plants.
Topics: Helianthus; Apoptosis; Polyamines; Plant Tubers
PubMed: 38791426
DOI: 10.3390/ijms25105386 -
Magnetic Resonance in Medicine May 2024Prostate tissue has a complex microstructure, mainly composed of epithelial and stromal cells, and of extracellular (acinar-luminal) spaces. Diffusion-weighted MR...
PURPOSE
Prostate tissue has a complex microstructure, mainly composed of epithelial and stromal cells, and of extracellular (acinar-luminal) spaces. Diffusion-weighted MR spectroscopy (DW-MRS) is ideally suited to explore complex microstructure in vivo with metabolites selectively distributed in different subspaces. To date, this technique has been applied to brain and muscle. This study presents the development and pioneering utilization of H-DW-MRS in the prostate, accompanied by in vitro studies to support interpretations of in vivo findings.
METHODS
Nine healthy volunteers underwent a prostate MR examination (mean age, 56 years; range, 31-66). Metabolic complexation was studied in vitro using solutions with major compounds found in prostatic fluid of the lumen. DW-MRS was performed at 3 T with a non-water-suppressed single-voxel sequence with metabolite-cycling to concurrently measure metabolite and water signals. The water signal was used in postprocessing as a reference in a motion-compensation scheme. The spectra were fitted simultaneously in the spectral and diffusion-weighting dimensions. Apparent diffusion coefficients (ADCs) were derived by fitting signal decays that were assumed to be mono-exponential for metabolites and biexponential for water.
RESULTS
DW-MRS of the prostate revealed relatively low ADCs for Cho and Cr compounds, aligning with their intracellular location and higher ADCs for citrate and spermine supporting their luminal origin. In vitro assessments of the ADCs of citrate and spermine demonstrated their complex formation and protein binding. Tissue concentrations of MRS-detectable metabolites were as expected for the voxel location.
CONCLUSIONS
This work successfully demonstrates the feasibility of H-DW-MRS of the prostate and its potential for providing valuable microstructural information.
PubMed: 38775024
DOI: 10.1002/mrm.30141 -
Rare : Open Research in Rare Diseases 2024Snyder-Robinson syndrome (SRS) is a rare X-linked recessive disorder characterized by a collection of clinical features including mild to severe intellectual disability,...
Snyder-Robinson syndrome (SRS) is a rare X-linked recessive disorder characterized by a collection of clinical features including mild to severe intellectual disability, hypertonia, marfanoid habitus, facial asymmetry, osteoporosis, developmental delay and seizures. Whole genome sequencing (WGS) identified a mutation in the spermine synthase () gene (c.746 A>G, p.Tyr249Cys) in a male with kyphosis, seizures, and osteoporosis. His phenotype is unique in that he does not have intellectual disability (ID) but does have a mild learning disability. This case demonstrates a milder presentation of SRS and expands the phenotype beyond the reported literature.
PubMed: 38770537
DOI: 10.1016/j.rare.2023.100017 -
Chemico-biological Interactions Jun 2024Chronic inflammation, oxidative stress, and airway remodelling represent the principal pathophysiological features of chronic respiratory disorders. Inflammation stimuli...
Chronic inflammation, oxidative stress, and airway remodelling represent the principal pathophysiological features of chronic respiratory disorders. Inflammation stimuli like lipopolysaccharide (LPS) activate macrophages and dendritic cells, with concomitant M1 polarization and release of pro-inflammatory cytokines. Chronic inflammation and oxidative stress lead to airway remodelling causing irreversible functional and structural alterations of the lungs. Airway remodelling is multifactorial, however, the hormone transforming growth factor-β (TGF-β) is one of the main contributors to fibrotic changes. The signalling pathways mediating inflammation and remodelling rely both on the transcription factor nuclear factor-κB (NFκB), underlying the potential of NFκB inhibition as a therapeutic strategy for chronic respiratory disorders. In this study, we encapsulated an NFκB-inhibiting decoy oligodeoxynucleotide (ODN) in spermine-functionalized acetalated dextran (SpAcDex) nanoparticles and tested the in vitro anti-inflammatory and anti-remodelling activity of this formulation. We show that NF-κB ODN nanoparticles counteract inflammation by reversing LPS-induced expression of the activation marker CD40 in myeloid cells and counteracts remodelling features by reversing the TGF-β-induced expression of collagen I and α-smooth muscle actin in human dermal fibroblast. In summary, our study highlights the great potential of inhibiting NFκB via decoy ODN as a therapeutic strategy tackling multiple pathophysiological features underlying chronic respiratory conditions.
Topics: Oligodeoxyribonucleotides; Humans; Nanoparticles; Anti-Inflammatory Agents; NF-kappa B; Spermine; Lipopolysaccharides; Transforming Growth Factor beta; Fibroblasts; Fibrosis
PubMed: 38761875
DOI: 10.1016/j.cbi.2024.111059 -
Molecular Pain 2024Recent studies using different experimental approaches demonstrate that silent synapses may exist in the adult cortex including the sensory cortex and anterior cingulate...
Recent studies using different experimental approaches demonstrate that silent synapses may exist in the adult cortex including the sensory cortex and anterior cingulate cortex (ACC). The postsynaptic form of long-term potentiation (LTP) in the ACC recruits some of these silent synapses and the activity of calcium-stimulated adenylyl cyclases (ACs) is required for such recruitment. It is unknown if the chemical activation of ACs may recruit silent synapses. In this study, we found that activation of ACs contributed to synaptic potentiation in the ACC of adult mice. Forskolin, a selective activator of ACs, recruited silent responses in the ACC of adult mice. The recruitment was long-lasting. Interestingly, the effect of forskolin was not universal, some silent synapses did not undergo potentiation or recruitment. These findings suggest that these adult cortical synapses are not homogenous. The application of a selective calcium-permeable AMPA receptor inhibitor 1-naphthyl acetyl spermine (NASPM) reversed the potentiation and the recruitment of silent responses, indicating that the AMPA receptor is required. Our results strongly suggest that the AC-dependent postsynaptic AMPA receptor contributes to the recruitment of silent responses at cortical LTP.
Topics: Animals; Mice; Gyrus Cinguli; Colforsin; Long-Term Potentiation; Adenylyl Cyclases; Male; Receptors, AMPA; Mice, Inbred C57BL; Synapses; Calcium
PubMed: 38744422
DOI: 10.1177/17448069241258110 -
Cell Death & Disease May 2024Precise polyamine metabolism regulation is vital for cells and organisms. Mutations in spermine synthase (SMS) cause Snyder-Robinson intellectual disability syndrome...
Precise polyamine metabolism regulation is vital for cells and organisms. Mutations in spermine synthase (SMS) cause Snyder-Robinson intellectual disability syndrome (SRS), characterized by significant spermidine accumulation and autophagy blockage in the nervous system. Emerging evidence connects polyamine metabolism with other autophagy-related diseases, such as Tauopathy, however, the functional intersection between polyamine metabolism and autophagy in the context of these diseases remains unclear. Here, we altered SMS expression level to investigate the regulation of autophagy by modulated polyamine metabolism in Tauopathy in Drosophila and human cellular models. Interestingly, while complete loss of Drosophila spermine synthase (dSms) impairs lysosomal function and blocks autophagic flux recapitulating SRS disease phenotype, partial loss of dSms enhanced autophagic flux, reduced Tau protein accumulation, and led to extended lifespan and improved climbing performance in Tauopathy flies. Measurement of polyamine levels detected a mild elevation of spermidine in flies with partial loss of dSms. Similarly, in human neuronal or glial cells, partial loss of SMS by siRNA-mediated knockdown upregulated autophagic flux and reduced Tau protein accumulation. Importantly, proteomics analysis of postmortem brain tissue from Alzheimer's disease (AD) patients showed a significant albeit modest elevation of SMS level. Taken together, our study uncovers a functional correlation between polyamine metabolism and autophagy in AD: SMS reduction upregulates autophagy, suppresses Tau accumulation, and ameliorates neurodegeneration and cell death. These findings provide a new potential therapeutic target for AD.
Topics: Autophagy; Animals; tau Proteins; Humans; Spermine Synthase; Drosophila melanogaster; Drosophila Proteins; Tauopathies; Neurons; Alzheimer Disease; Spermidine; Disease Models, Animal; Lysosomes; Drosophila; Mental Retardation, X-Linked
PubMed: 38740758
DOI: 10.1038/s41419-024-06720-8 -
Biomedicine & Pharmacotherapy =... Jun 2024Osteoporosis is a systemic bone disease characterized by decreased bone mass that is tightly regulated by the coordinated actions of osteoclasts and osteoblasts....
Osteoporosis is a systemic bone disease characterized by decreased bone mass that is tightly regulated by the coordinated actions of osteoclasts and osteoblasts. Apoptosis as a precise programmed cell death involves a cascade of gene expression events which are mechanistically linked to the regulation of bone metabolism. Nevertheless, the critical biomolecules involved in regulating cell apoptosis in osteoporosis remain unknown. To gain a deeper insight into the relationship between apoptosis and osteoporosis, this study integrated the sequencing results of human samples and using a machine learning workflow to overcome the limitations of a single study. Among all immune cell populations, we assessed the apoptotic level and portrayed the distinct subtypes and lineage differentiation of monocytic cells in osteoporotic tissues. Osteoclasts expressed a higher level of Spermidine/spermine-N1-Acetyltransferase1 (SAT1) during osteoclastogenesis which prevented osteoclasts apoptosis and facilitate osteoporosis progression. In addition, Berenil, one potent SAT1 inhibitor, increased osteoclast apoptosis and reversed the bone loss in the femurs of a murine ovariectomy model. In summary, Berenil promotes osteoclast apoptosis, inhibits the bone resorption and improves the abnormal bone structure in vitro and in vivo models by targeting SAT1, demonstrating its potential as a precise therapeutic strategy for clinical osteoporosis treatment.
Topics: Apoptosis; Animals; Osteoclasts; Osteoporosis; Humans; Female; Mice; Acetyltransferases; Mice, Inbred C57BL; Bone Resorption; Ovariectomy; Osteogenesis; Cell Differentiation; Disease Models, Animal
PubMed: 38739990
DOI: 10.1016/j.biopha.2024.116732 -
RSC Chemical Biology May 2024The enzymatic synthesis of xenobiotic nucleic acids (XNA), which are artificially sugar-modified nucleic acids, is essential for the preparation of XNA libraries. XNA...
The enzymatic synthesis of xenobiotic nucleic acids (XNA), which are artificially sugar-modified nucleic acids, is essential for the preparation of XNA libraries. XNA libraries are used in the selection of XNA aptamers and enzymes (XNAzymes). Efficient enzymatic synthesis of various XNAs can enable the screening of high-quality XNA aptamers and XNAzymes by expanding the diversity of XNA libraries and adding a variety of properties to XNA aptamers and XNAzymes. However, XNAs that form unstable duplexes with DNA, such as arabino nucleic acid (ANA), may dissociate during enzyme synthesis at temperatures suitable for thermophilic polymerases. Thus, such XNAs are not efficiently synthesised by the thermophilic polymerase mutants at the end of the sequence. This undesirable bias reduces the possibility of generating high-quality XNA aptamers and XNAzymes. Here, we demonstrate that polyamine-induced DNA/ANA duplex stabilisation promotes ANA synthesis that is catalysed by thermophilic polymerase mutants. Several polyamines, including spermine, spermidine, cadaverine, and putrescine promote ANA synthesis. The negative effect of polyamines on the fidelity of ANA synthesis was negligible. We also showed that polyamines promote the synthesis of other XNAs, including 2'-amino-RNA/2'-fluoro-RNA mixture and 2'--methyl-RNA. In addition, we found that polyamine promotes DNA synthesis from the 2'--methyl-RNA template. Polyamines, with the use of thermophilic polymerase mutants, may allow further development of XNA aptamers and XNAzymes by promoting the transcription and reverse transcription of XNAs.
PubMed: 38725908
DOI: 10.1039/d4cb00017j -
Spectrochimica Acta. Part A, Molecular... Sep 2024Over the years, osteosarcoma therapy has had a significative improvement with the use of a multidrug regime strategy, increasing the survival rates from less than 20 %...
Over the years, osteosarcoma therapy has had a significative improvement with the use of a multidrug regime strategy, increasing the survival rates from less than 20 % to circa 70 %. Different types of development of new antineoplastic agents are critical to achieve irreversible damage to cancer cells, while preserving the integrity of their healthy counterparts. In the present study, complexes with two and three Pd(II) centres linked by the biogenic polyamines: spermine (PdSpmCl) and spermidine (PdSpdCl) were tested against non-malignant (osteoblasts, HOb) and cancer (osteosarcoma, MG-63) human cell lines. Either alone or in combination according to the EURAMOS-1 protocol, they were used versus cisplatin as a drug reference. By evaluating the cytotoxic effects of both therapeutic approaches (single and drug combination) in HOb and MG-63 cell lines, the selective anti-tumoral potential is assessed. To understand the different treatments at a molecular level, Synchrotron Radiation Fourier Transform Infrared and Raman microspectroscopies were applied. Principal component analysis and hierarchical cluster analysis are applied to the vibrational data, revealing the major metabolic changes caused by each drug, which were found to rely on DNA, lipids, and proteins, acting as biomarkers of drug-to-cell impact. The main changes were observed for the B-DNA native conformation to either Z-DNA (higher in the presence of polynuclear complexes) or A-DNA (preferably after cisplatin exposure). Additionally, a higher effect upon variation in proteins content was detected in drug combination when compared to single drug administration proving the efficacy of the EURAMOS-1 protocol with the new drugs tested.
Topics: Humans; Osteosarcoma; Spectrum Analysis, Raman; Antineoplastic Agents; Cell Line, Tumor; Spectroscopy, Fourier Transform Infrared; Vibration; Spermine; Bone Neoplasms; Spermidine; Principal Component Analysis; Cell Survival
PubMed: 38710137
DOI: 10.1016/j.saa.2024.124389