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Scientific Reports Jan 2024Leishmania amazonensis is a protozoan that primarily causes cutaneous leishmaniasis in humans. The parasite relies on the amino acid arginine to survive within...
Leishmania amazonensis is a protozoan that primarily causes cutaneous leishmaniasis in humans. The parasite relies on the amino acid arginine to survive within macrophages and establish infection, since it is a precursor for producing polyamines. On the other hand, arginine can be metabolized via nitric oxide synthase 2 (NOS2) to produce the microbicidal molecule nitric oxide (NO), although this mechanism does not apply to human macrophages since they lack NOS2 activity. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at posttranscriptional levels. Our previous work showed that mmu-miR-294 targets Nos2 favoring Leishmania survival in murine macrophages. Here, we demonstrate that human macrophages upregulate the hsa-miR-372, hsa-miR-373, and hsa-miR-520d, which present the same seed sequence as the murine mmu-miR-294. Inhibition of the miR-372 impaired Leishmania survival in THP-1 macrophages and the effect was further enhanced with combinatorial inhibition of the miR-372/373/520d family, pointing to a cooperative mechanism. However, this reduction in survival is not caused by miRNA-targeting of NOS2, since the seed-binding motif found in mice is not conserved in the human 3'UTR. Instead, we showed the miR-372/373/520d family targeting the macrophage's main arginine transporter SLC7A2/CAT2 during infection. Arginine-related metabolism was markedly altered in response to infection and miRNA inhibition, as measured by Mass Spectrometry-based metabolomics. We found that Leishmania infection upregulates polyamines production in macrophages, as opposed to simultaneous inhibition of miR-372/373/520d, which decreased putrescine and spermine levels compared to the negative control. Overall, our study demonstrates miRNA-dependent modulation of polyamines production, establishing permissive conditions for intracellular parasite survival. Although the effector mechanisms causing host cell immunometabolic adaptations involve various parasite and host-derived signals, our findings suggest that the miR-372/373/520d family may represent a potential target for the development of new therapeutic strategies against cutaneous leishmaniasis.
Topics: Humans; Animals; Mice; Leishmaniasis, Cutaneous; Leishmania; Arginine; Macrophages; MicroRNAs
PubMed: 38200138
DOI: 10.1038/s41598-024-51511-y -
Plant & Cell Physiology Apr 2024Thermospermine suppresses auxin-inducible xylem differentiation, whereas its structural isomer, spermine, is involved in stress responses in angiosperms. The...
Thermospermine suppresses auxin-inducible xylem differentiation, whereas its structural isomer, spermine, is involved in stress responses in angiosperms. The thermospermine synthase, ACAULIS5 (ACL5), is conserved from algae to land plants, but its physiological functions remain elusive in non-vascular plants. Here, we focused on MpACL5, a gene in the liverwort Marchantia polymorpha, that rescued the dwarf phenotype of the acl5 mutant in Arabidopsis. In the Mpacl5 mutants generated by genome editing, severe growth retardation was observed in the vegetative organ, thallus, and the sexual reproductive organ, gametangiophore. The mutant gametangiophores exhibited remarkable morphological defects such as short stalks, fasciation and indeterminate growth. Two gametangiophores fused together, and new gametangiophores were often initiated from the old ones. Furthermore, Mpacl5 showed altered responses to heat and salt stresses. Given the absence of spermine in bryophytes, these results suggest that thermospermine has a dual primordial function in organ development and stress responses in M. polymorpha. The stress response function may have eventually been assigned to spermine during land plant evolution.
Topics: Spermine; Plant Growth Regulators; Arabidopsis Proteins; Marchantia; Arabidopsis; Plants
PubMed: 38179828
DOI: 10.1093/pcp/pcae002 -
Frontiers in Pharmacology 2023Oligoarginine peptides, known mostly for their cell-penetrating properties, are also inhibitors of the nicotinic acetylcholine receptors (nAChRs). Since octa-arginine...
Oligoarginine peptides, known mostly for their cell-penetrating properties, are also inhibitors of the nicotinic acetylcholine receptors (nAChRs). Since octa-arginine (R8) inhibits α9α10 nAChR and suppresses neuropathic pain, we checked if other polycationic compounds containing amino and/or guanidino groups could be effective and tested the activity of the disulfide-fixed "cyclo"R8, a series of biogenic polyamines (putrescine, spermidine, and spermine), -methylated spermine analogs, agmatine and its analogs, as well as acylpolyamine argiotoxin-636 from spider venom. Their inhibitory potency on muscle-type, α7 and α9α10 nAChRs was determined using radioligand analysis, electrophysiology, and calcium imaging. "Cyclo"R8 showed similar activity to that of R8 against α9α10 nAChR (IC ≈ 60 nM). Biogenic polyamines as well as agmatine and its analogs displayed low activity on muscle-type , as well as α7 and α9α10 nAChRs, which increased with chain length, the most active being spermine and its -methylated derivatives having IC of about 30 μM against muscle-type nAChR. Argiotoxin-636, which contains a polyamine backbone and terminal guanidino group, also weakly inhibited nAChR (IC ≈ 15 μM), but it revealed high potency against rat α9α10 nAChR (IC ≈ 200 nM). We conclude that oligoarginines and similar polycationic compounds effectively inhibiting α9α10 nAChR may serve as a basis for the development of analgesics to reduce neuropathic pain.
PubMed: 38169863
DOI: 10.3389/fphar.2023.1327603 -
Frontiers in Physiology 2023The Manila clam (), as one of the shellfish living in the intertidal zone, is known for its strong ability to withstand air exposure. Sodium nitroprusside (SNP), a donor...
The Manila clam (), as one of the shellfish living in the intertidal zone, is known for its strong ability to withstand air exposure. Sodium nitroprusside (SNP), a donor of nitric oxide (NO), has been shown to be useful for antioxidant and immune regulation in aquatic animals. In this study, an untargeted metabolomics (LC-MS/MS) technique was employed for the first time in Manila clam to analyze the metabolic and histological impacts after air exposure and the positive effects of SNP pretreatment. During air exposure, a significant increase in taurine, L-glutamate, and several polyunsaturated fatty acids in clams was detected, which indicates that clams may experience inflammatory reactions, oxidative stress, and an increase in blood ammonia content. When clams were exposed to SNP for 6 h, arginine, spermine, L-glutamic acid, and glutathione content were all upregulated, indicating that the SNP exposure induced NO production and improved antioxidant capacity in clams. When the clams were exposed to air after SNP pretreatment, there were no significant differences in the levels of taurine, L-glutamate, or aliphatic acids between the experimental and control groups. Gill tissue was more severely damaged in clams directly exposed to air than in those that experienced air exposure after SNP pretreatment, especially in clams exposed to air for a long time (72 h). Both metabolomics and tissue section structure indicated that SNP pretreatment decreased the stress responses caused by air exposure in . These findings provided fresh insights and a theoretical foundation for understanding the tolerance to air exposure and physiological functions of SNP (or NO) in .
PubMed: 38162826
DOI: 10.3389/fphys.2023.1308777 -
International Journal of Molecular... Dec 2023This work investigated the mechanisms of action of conventional drugs, cisplatin and oxaliplatin, and the potentially less deleterious drug PdSpermine (Spm) and its...
This work investigated the mechanisms of action of conventional drugs, cisplatin and oxaliplatin, and the potentially less deleterious drug PdSpermine (Spm) and its Pt(II) analog, against osteosarcoma MG-63 cells, using nuclear-magnetic-resonance metabolomics of the cellular lipidome. The Pt(II) chelates induced different responses, namely regarding polyunsaturated-fatty-acids (increased upon cisplatin), suggesting that cisplatin-treated cells have higher membrane fluidity/permeability, thus facilitating cell entry and justifying higher cytotoxicity. Both conventional drugs significantly increased triglyceride levels, while PtSpm maintained control levels; this may reflect enhanced apoptotic behavior for conventional drugs, but not for PtSpm. Compared to PtSpm, the more cytotoxic PdSpm (IC comparable to cisplatin) induced a distinct phospholipids profile, possibly reflecting enhanced de novo biosynthesis to modulate membrane fluidity and drug-accessibility to cells, similarly to cisplatin. However, PdSpm differed from cisplatin in that cells had equivalent (low) levels of triglycerides as PtSpm, suggesting the absence/low extent of apoptosis. Our results suggest that PdSpm acts on MG-63 cells mainly through adaptation of cell membrane fluidity, whereas cisplatin seems to couple a similar effect with typical signs of apoptosis. These results were discussed in articulation with reported polar metabolome adaptations, building on the insight of these drugs' mechanisms, and particularly of PdSpm as a possible cisplatin substitute.
Topics: Humans; Cisplatin; Lipid Metabolism; Antineoplastic Agents; Osteosarcoma; Spermine; Apoptosis; Bone Neoplasms; Cell Line, Tumor
PubMed: 38139388
DOI: 10.3390/ijms242417556 -
Biomolecules Dec 2023Protein-nanoparticle hybridization can ideally lead to novel biological entities characterized by emerging properties that can sensibly differ from those of the parent...
Protein-nanoparticle hybridization can ideally lead to novel biological entities characterized by emerging properties that can sensibly differ from those of the parent components. Herein, the effect of ionic strength on the biological functions of recombinant His-tagged spermine oxidase (i.e., SMOX) was studied for the first time. Moreover, SMOX was integrated into colloidal surface active maghemite nanoparticles (SAMNs) via direct self-assembly, leading to a biologically active nano-enzyme (i.e., SAMN@SMOX). The hybrid was subjected to an in-depth chemical-physical characterization, highlighting the fact that the protein structure was perfectly preserved. The catalytic activity of the nanostructured hybrid (SAMN@SMOX) was assessed by extracting the kinetics parameters using spermine as a substrate and compared to the soluble enzyme as a function of ionic strength. The results revealed that the catalytic function was dominated by electrostatic interactions and that they were drastically modified upon hybridization with colloidal ɣ-FeO. The fact that the affinity of SMOX toward spermine was significantly higher for the nanohybrid at low salinity is noteworthy. The present study supports the vision of using protein-nanoparticle conjugation as a means to modulate biological functions.
Topics: Polyamine Oxidase; Spermine; Static Electricity; Oxidoreductases Acting on CH-NH Group Donors; Nanoparticles
PubMed: 38136670
DOI: 10.3390/biom13121800 -
Saudi Journal of Biological Sciences Jan 2024Epithelial cancer cells rely on the extracellular matrix (ECM) attachment in order to spread to other organs. Detachment from the ECM is necessary for these cells to...
Epithelial cancer cells rely on the extracellular matrix (ECM) attachment in order to spread to other organs. Detachment from the ECM is necessary for these cells to seed in other locations. When the attachment to the ECM is lost, cellular metabolism undergoes a significant shift from oxidative metabolism to glycolysis. Additionally, the cancer cells become more dependent on glutaminolysis to avoid a specific type of cell death known as anoikis, which is associated with ECM detachment. In our recent study, we observed increased expression of H3K27me3 demethylases, specifically KDM6A/B, in cancer cells that were resistant to anoikis. Since KDM6A/B is known to regulate cellular metabolism, we investigated the effects of suppressing KDM6A/B with GSK-J4 on the metabolic processes in these anoikis-resistant cancer cells. Our results from untargeted metabolomics revealed a profound impact of KDM6A/B inhibition on various metabolic pathways, including glycolysis, methyl histidine, spermine, and glutamate metabolism. Inhibition of KDM6A/B led to elevated reactive oxygen species (ROS) levels and depolarization of mitochondria, while reducing the levels of glutathione, an important antioxidant, by diminishing the intermediates of the glutamate pathway. Glutamate is crucial for maintaining a pool of reduced glutathione. Furthermore, we discovered that KDM6A/B regulates the key glycolytic genes expression like hexokinase, lactate dehydrogenase, and GLUT-1, which are essential for sustaining glycolysis in anoikis-resistant cancer cells. Overall, our findings demonstrated the critical role of KDM6A/B in maintaining glycolysis, glutamate metabolism, and glutathione levels. Inhibition of KDM6A/B disrupts these metabolic processes, leading to increased ROS levels and triggering cell death in anoikis-resistant cancer cells.
PubMed: 38107766
DOI: 10.1016/j.sjbs.2023.103871 -
Cell Reports Dec 2023Natural polyamines such as spermidine and spermine cations have characteristics that make them highly likely to be sensed by riboswitches, such as their general affinity...
Natural polyamines such as spermidine and spermine cations have characteristics that make them highly likely to be sensed by riboswitches, such as their general affinity to polyanionic RNA and their broad contributions to cell physiology. Despite previous claims that polyamine riboswitches exist, evidence of their biological functions has remained unconvincing. Here, we report that rare variants of bacterial S-adenosylmethionine-I (SAM-I) riboswitches reject SAM and have adapted to selectively sense spermidine. These spermidine-sensing riboswitch variants are associated with genes whose protein products are directly involved in the production of spermidine and other polyamines. Biochemical and genetic assays demonstrate that representatives of this riboswitch class robustly function as genetic "off" switches, wherein spermidine binding causes premature transcription termination to suppress the expression of polyamine biosynthetic genes. These findings confirm the existence of natural spermidine-sensing riboswitches in bacteria and expand the list of variant riboswitch classes that have adapted to bind different ligands.
Topics: Riboswitch; S-Adenosylmethionine; Spermidine; Coenzymes; Oligonucleotides; Bacteria; Nucleic Acid Conformation
PubMed: 38096053
DOI: 10.1016/j.celrep.2023.113571 -
Microbiology Spectrum Jan 2024This is the first study that attempted to demonstrate the mechanisms of reactive oxygen species (ROS) generation by spermine (Spm) in (M.tb). Furthermore, this is the...
This is the first study that attempted to demonstrate the mechanisms of reactive oxygen species (ROS) generation by spermine (Spm) in (M.tb). Furthermore, this is the first study to demonstrate that it is able to enhance the activity of currently available and World Health Organization (WHO)-approved tuberculosis (TB) drugs. Spermine can easily be obtained since it is already found in our diet. Moreover, as opposed to conventional antibiotics, it is less toxic to humans since it is found in millimolar concentrations in the body. Finally, with the difficulty of curing TB with conventional antibiotics, this study suggests that less toxic molecules, such as Spm, could in a long-term perspective be incorporated in a TB regimen to boost the treatment.
Topics: Humans; Antitubercular Agents; Spermine; Isoniazid; Rifampin; Tuberculosis; Mycobacterium tuberculosis; Tuberculosis, Multidrug-Resistant; Microbial Sensitivity Tests
PubMed: 38095461
DOI: 10.1128/spectrum.03568-23 -
Biochimica Et Biophysica Acta.... Feb 2024The molecular mechanisms behind electrotaxis remain largely unknown, with no identified primary direct current electric field (dcEF) sensor. Two leading hypotheses...
The molecular mechanisms behind electrotaxis remain largely unknown, with no identified primary direct current electric field (dcEF) sensor. Two leading hypotheses propose mechanisms involving the redistribution of charged components in the cell membrane (driven by electrophoresis or electroosmosis) and the asymmetric activation of ion channels. To investigate these mechanisms, we studied the dynamics of electrotactic behaviour of mouse 3T3 fibroblasts. We observed that 3T3 fibroblasts exhibit cathodal migration within just 1 min when exposed to physiological dcEF. This rapid response suggests the involvement of ion channels in the cell membrane. Our large-scale screening method identified several ion channel genes as potential key players, including the inwardly rectifying potassium channel Kir4.2. Blocking the Kir channel family with Ba or silencing the Kcnj15 gene, encoding Kir4.2, significantly reduced the directional migration of 3T3 cells. Additionally, the levels of the intracellular regulators of Kir channels, spermine (SPM) and spermidine (SPD), had a significant impact on cell directionality. Interestingly, inhibiting Kir4.2 resulted in the temporary cessation of electrotaxis for approximately 1-2 h before its return. This observation suggests a two-phase mechanism for the electrotaxis of mouse 3T3 fibroblasts, where ion channel activation triggers the initial rapid response to dcEF, and the subsequent redistribution of membrane receptors sustains long-term directional movement. In summary, our study unveils the involvement of Kir channels and proposes a biphasic mechanism to explain the electrotactic behaviour of mouse 3T3 fibroblasts, shedding light on the molecular underpinnings of electrotaxis.
Topics: Mice; Animals; Cell Movement; Cell Membrane; Fibroblasts; Spermidine; Ion Channels
PubMed: 38092134
DOI: 10.1016/j.bbamcr.2023.119647