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Environmental Science & Technology Sep 2023The rubber antioxidant 6PPD has gained significant attention due to its highly toxic transformation product, 6PPD-quinone (6PPDQ). Despite their detection in urines of...
The rubber antioxidant 6PPD has gained significant attention due to its highly toxic transformation product, 6PPD-quinone (6PPDQ). Despite their detection in urines of pregnant women, the placental transfer and developmental toxicity of 6PPD and 6PPDQ are unknown. Here, we treated C57Bl/6 mice with 4 mg/kg 6PPD or 6PPDQ to investigate their urine excretion and placental transfer. Female and male mice exhibited sex difference in excretion profiles of 6PPD and 6PPDQ. Urine concentrations of 6PPDQ were one order of magnitude lower than those of 6PPD, suggesting lower excretion and higher bioaccumulation of 6PPDQ. In pregnant mice treated with 6PPD or 6PPDQ from embryonic day 11.5 to 15.5, 6PPDQ showed ∼1.5-8 times higher concentrations than 6PPD in placenta, embryo body, and embryo brain, suggesting higher placental transfer of 6PPDQ. Using in vitro dual-luciferase reporter assays, we revealed that 6PPDQ activated the human retinoic acid receptor α (RARα) and retinoid X receptor α (RXRα) at concentrations as low as 0.3 μM, which was ∼10-fold higher than the concentrations detected in human urines. 6PPD activated the RXRα at concentrations as low as 1.2 μM. These results demonstrate the exposure risks of 6PPD and 6PPDQ during pregnancy and emphasize the need for further toxicological and epidemiological investigations.
Topics: Animals; Female; Humans; Male; Mice; Pregnancy; Benzoquinones; Placenta; Phenylenediamines; Mice, Inbred C57BL; Tissue Distribution; Sex Factors; Embryonic Development; HEK293 Cells; Retinoic Acid Receptor alpha; Retinoid X Receptor alpha
PubMed: 37642336
DOI: 10.1021/acs.est.3c05026 -
Nature Feb 2024The calcium-sensing receptor (CaSR) is a family C G-protein-coupled receptor (GPCR) that has a central role in regulating systemic calcium homeostasis. Here we use...
The calcium-sensing receptor (CaSR) is a family C G-protein-coupled receptor (GPCR) that has a central role in regulating systemic calcium homeostasis. Here we use cryo-electron microscopy and functional assays to investigate the activation of human CaSR embedded in lipid nanodiscs and its coupling to functional G versus G proteins in the presence and absence of the calcimimetic drug cinacalcet. High-resolution structures show that both G and G drive additional conformational changes in the activated CaSR dimer to stabilize a more extensive asymmetric interface of the seven-transmembrane domain (7TM) that involves key protein-lipid interactions. Selective G and G coupling by the receptor is achieved through substantial rearrangements of intracellular loop 2 and the C terminus, which contribute differentially towards the binding of the two G-protein subtypes, resulting in distinct CaSR-G-protein interfaces. The structures also reveal that natural polyamines target multiple sites on CaSR to enhance receptor activation by zipping negatively charged regions between two protomers. Furthermore, we find that the amino acid L-tryptophan, a well-known ligand of CaSR extracellular domains, occupies the 7TM bundle of the G-protein-coupled protomer at the same location as cinacalcet and other allosteric modulators. Together, these results provide a framework for G-protein activation and selectivity by CaSR, as well as its allosteric modulation by endogenous and exogenous ligands.
Topics: Humans; Allosteric Regulation; Cinacalcet; Cryoelectron Microscopy; GTP-Binding Protein alpha Subunits, Gi-Go; GTP-Binding Protein alpha Subunits, Gq-G11; Heterotrimeric GTP-Binding Proteins; Ligands; Lipids; Nanostructures; Polyamines; Protein Conformation; Receptors, Calcium-Sensing; Substrate Specificity; Tryptophan; Calcium
PubMed: 38326620
DOI: 10.1038/s41586-024-07055-2 -
Scientific Reports Oct 2023Herbaceous peony is a perennial root plant that likes light and is cold-resistant. During summer, high temperature and strong light intensity advance its entry into the...
Herbaceous peony is a perennial root plant that likes light and is cold-resistant. During summer, high temperature and strong light intensity advance its entry into the leaf wilting stage, which limits the accumulation of nutrients and formation of strong buds and severely affects its growth and development the following year. In this study, the wild herbaceous peony species and two main cultivars, 'Zifengyu' and 'Hongfengyu', were subjected to slight shading and strong light environments in summer, and their effects on leaf senescence and endogenous hormone and polyamine contents were explored. Slight shading treatment significantly delayed withering, increased the leaf net photosynthetic rate, and increased the chlorophyll, soluble sugar, indole-3-acetic acid, zeatin, gibberellin, spermine, spermidine, putrescine, and polyamine contents. Additionally, slight shading significantly reduced the proline and abscisic acid contents. Slight shading during summer prolonged the green period and delayed leaf senescence. The tolerance of tested materials to strong light intensity in summer was ranked as follows: 'Zifengyu' > 'Hongfengyu' > wild species. In conclusion, this study revealed that summer leaf senescence is delayed in herbaceous peony through shading and growth regulators. Additional varieties should be evaluated to provide reference for high-efficiency, high-quality, and high-yield cultivation of herbaceous peony.
Topics: Paeonia; Polyamines; Plant Senescence; Photosynthesis; Hormones; Plants; Plant Leaves
PubMed: 37907675
DOI: 10.1038/s41598-023-46192-y -
Cardiovascular Research May 2024Potential loss-of-function variants of ATP13A3, the gene encoding a P5B-type transport ATPase of undefined function, were recently identified in patients with pulmonary...
AIMS
Potential loss-of-function variants of ATP13A3, the gene encoding a P5B-type transport ATPase of undefined function, were recently identified in patients with pulmonary arterial hypertension (PAH). ATP13A3 is implicated in polyamine transport but its function has not been fully elucidated. In this study, we sought to determine the biological function of ATP13A3 in vascular endothelial cells (ECs) and how PAH-associated variants may contribute to disease pathogenesis.
METHODS AND RESULTS
We studied the impact of ATP13A3 deficiency and overexpression in EC models [human pulmonary ECs, blood outgrowth ECs (BOECs), and human microvascular EC 1], including a PAH patient-derived BOEC line harbouring an ATP13A3 variant (LK726X). We also generated mice harbouring an Atp13a3 variant analogous to a human disease-associated variant to establish whether these mice develop PAH. ATP13A3 localized to the recycling endosomes of human ECs. Knockdown of ATP13A3 in ECs generally reduced the basal polyamine content and altered the expression of enzymes involved in polyamine metabolism. Conversely, overexpression of wild-type ATP13A3 increased polyamine uptake. Functionally, loss of ATP13A3 was associated with reduced EC proliferation, increased apoptosis in serum starvation, and increased monolayer permeability to thrombin. The assessment of five PAH-associated missense ATP13A3 variants (L675V, M850I, V855M, R858H, and L956P) confirmed loss-of-function phenotypes represented by impaired polyamine transport and dysregulated EC function. Furthermore, mice carrying a heterozygous germline Atp13a3 frameshift variant representing a human variant spontaneously developed a PAH phenotype, with increased pulmonary pressures, right ventricular remodelling, and muscularization of pulmonary vessels.
CONCLUSION
We identify ATP13A3 as a polyamine transporter controlling polyamine homeostasis in ECs, a deficiency of which leads to EC dysfunction and predisposes to PAH. This suggests a need for targeted therapies to alleviate the imbalances in polyamine homeostasis and EC dysfunction in PAH.
Topics: Animals; Humans; Polyamines; Endothelial Cells; Cell Proliferation; Pulmonary Artery; Proton-Translocating ATPases; Pulmonary Arterial Hypertension; Apoptosis; Hypertension, Pulmonary; Endosomes; Biological Transport; Disease Models, Animal; Cells, Cultured; Phenotype; Mice, Inbred C57BL; Mice
PubMed: 38626311
DOI: 10.1093/cvr/cvae068 -
The Journal of Biological Chemistry Aug 2023Polyamines are positively charged alkylamines ubiquitous among eukaryotes, prokaryotes, and archaea. Humans obtain polyamines through dietary intake, metabolic...
Polyamines are positively charged alkylamines ubiquitous among eukaryotes, prokaryotes, and archaea. Humans obtain polyamines through dietary intake, metabolic production, or uptake of polyamines made by gut microbes. The polyamine biosynthetic pathway used by most gut microbes differs from that used by human cells. This alternative pathway employs carboxyspermidine dehydrogenase (CASDH), an enzyme with limited characterization. Here, we solved a 1.94 Å X-ray crystal structure of Bacteroides fragilis CASDH by molecular replacement. BfCASDH is composed of three domains with a fold similar to saccharopine dehydrogenase but with a distinct active site arrangement. Using steady-state methods, we determined k and k/K for BfCASDH and Clostridium leptum CASDH using putrescine, diaminopropane, aspartate semi-aldehyde, NADH, and NADPH as substrates. These data revealed evidence of cooperativity in BfCASDH. Putrescine is the likely polyamine substrate and NADPH is the coenzyme used to complete the reaction, forming carboxyspermidine as a product. These data provide the first kinetic characterization of CASDH-a key enzyme in the production of microbial polyamines.
Topics: Humans; NADP; Oxidoreductases; Polyamines; Putrescine; Spermidine; Bacteroides fragilis
PubMed: 37437886
DOI: 10.1016/j.jbc.2023.105033 -
Journal of Alzheimer's Disease : JAD 2024A hypothesis of Alzheimer's disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli....
A hypothesis of Alzheimer's disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli. Polyamines are essential in nucleolar functions, such as RNA folding and ribonucleoprotein assembly. Changes in the nucleolar pool of anionic RNA and cationic polyamines acting as counterions can cause significant nucleolar dynamics. Polyamine synthesis reduces S-adenosylmethionine which, at low levels, triggers tau phosphorylation. Also, polyamine recycling reduces acetyl-CoA needed for acetylcholine, which is low in Alzheimer's disease. Extraordinary nucleolar expansion and/or contraction can disrupt epigenetic control in peri-nucleolar chromatin, such as chromosome 14 with the presenilin-1 gene; chromosome 21 with the amyloid precursor protein gene; chromosome 17 with the tau gene; chromosome 19 with the APOE4 gene; and the inactive X chromosome (Xi; aka "nucleolar satellite") with normally silent spermine synthase (polyamine synthesis) and spermidine/spermine-N1-acetyltransferase (polyamine recycling) alleles. Chromosomes 17, 19 and the Xi have high concentrations of Alu elements which can be transcribed by RNA polymerase III if positioned nucleosomes are displaced from the Alu elements. A sudden flood of Alu RNA transcripts can competitively bind nucleolin which is usually bound to Alu sequences in structural RNAs that stabilize the nucleolar heterochromatic shell. This Alu competition leads to loss of nucleolar integrity with leaking of nucleolar polyamines that cause aggregation of phosphorylated tau. The hypothesis was developed with key word searches (e.g., PubMed) using relevant terms (e.g., Alzheimer's, lupus, nucleolin) based on a systems biology approach and exploring autoimmune disease tautology, gaining synergistic insights from other diseases.
Topics: Humans; Polyamines; Alzheimer Disease; Cell Nucleolus; Autoimmune Diseases; RNA
PubMed: 38489184
DOI: 10.3233/JAD-231184 -
Toxins May 2024Polyamines (PAs) are polycationic biogenic amines ubiquitously present in all life forms and are involved in molecular signaling and interaction, determining cell fate... (Review)
Review
Polyamines (PAs) are polycationic biogenic amines ubiquitously present in all life forms and are involved in molecular signaling and interaction, determining cell fate (e.g., cell proliferation, dif-ferentiation, and apoptosis). The intricate balance in the PAs' levels in the tissues will determine whether beneficial or detrimental effects will affect homeostasis. It's crucial to note that endoge-nous polyamines, like spermine and spermidine, play a pivotal role in our understanding of neu-rological disorders as they interact with membrane receptors and ion channels, modulating neuro-transmission. In spiders and wasps, monoamines (histamine, dopamine, serotonin, tryptamine) and polyamines (spermine, spermidine, acyl polyamines) comprise, with peptides and other sub-stances, the low molecular weight fraction of the venom. Acylpolyamines are venom components exclusively from spiders and a species of solitary wasp, which cause inhibition chiefly of iono-tropic glutamate receptors (AMPA, NMDA, and KA iGluRs) and nicotinic acetylcholine receptors (nAChRs). The first venom acylpolyamines ever discovered (argiopines, Joro and Nephila toxins, and philanthotoxins) have provided templates for the design and synthesis of numerous analogs. Thus far, analogs with high potency exert their effect at nanomolar concentrations, with high se-lectivity toward their ionotropic and ligand receptors. These potent and selective acylpolyamine analogs can serve biomedical purposes and pest control management. The structural modification of acylpolyamine with photolabile and fluorescent groups converted these venom toxins into use-ful molecular probes to discriminate iGluRs and nAchRs in cell populations. In various cases, the linear polyamines, like spermine and spermidine, constituting venom acyl polyamine backbones, have served as cargoes to deliver active molecules via a polyamine uptake system on diseased cells for targeted therapy. In this review, we examined examples of biogenic amines that play an essential role in neural homeostasis and cell signaling, contributing to human health and disease outcomes, which can be present in the venom of arachnids and hymenopterans. With an empha-sis on the spider and wasp venom acylpolyamines, we focused on the origin, structure, derivatiza-tion, and biomedical and biotechnological application of these pharmacologically attractive, chemically modular venom components.
Topics: Animals; Polyamines; Spider Venoms; Insecticides; Wasps; Humans; Spiders
PubMed: 38922129
DOI: 10.3390/toxins16060234 -
Journal of Biotechnology Dec 2023The heterogeneity of the N-linked glycan profile of therapeutic monoclonal antibodies (mAbs) derived from animal cells affects therapeutic efficacy and, therefore, needs...
The heterogeneity of the N-linked glycan profile of therapeutic monoclonal antibodies (mAbs) derived from animal cells affects therapeutic efficacy and, therefore, needs to be appropriately controlled during the manufacturing process. In this study, we examined the effects of polyamines on the N-linked glycan profiles of mAbs produced by CHO DP-12 cells. Normal cell growth of CHO DP-12 cells and their growth arrest by α-difluoromethylornithine (DFMO), an inhibitor of the polyamine biosynthetic pathway, was observed when 0.5% fetal bovine serum was added to serum-free medium, despite the presence of cadaverine and aminopropylcadaverine, instead of putrescine and spermidine in cells. Polyamine depletion by DFMO increased IgG galactosylation, accompanied by β1,4-galactosyl transferase 1 (B4GAT1) mRNA elevation. Additionally, IgG production in polyamine-depleted cells was reduced by 30% compared to that in control cells. Therefore, we examined whether polyamine depletion induces an ER stress response. The results indicated increased expression levels of chaperones for glycoprotein folding in polyamine-depleted cells, suggesting that polyamine depletion causes ER stress related to glycoprotein folding. The effect of tunicamycin, an ER stress inducer that inhibits N-glycosylation, on the expression of B4GALT1 mRNA was examined. Tunicamycin treatment increased B4GALT1 mRNA expression. These results suggest that ER stress caused by polyamine depletion induces B4GALT1 mRNA expression, resulting in increased IgG galactosylation in CHO cells. Thus, introducing polyamines, particularly SPD, to serum-free CHO culture medium for CHO cells may contribute to consistent manufacturing and quality control of antibody production.
Topics: Cricetinae; Animals; Polyamines; CHO Cells; Antibodies, Monoclonal; Cricetulus; Tunicamycin; Putrescine; Eflornithine; RNA, Messenger; Glycoproteins; Polysaccharides; Immunoglobulin G; Spermine
PubMed: 37922995
DOI: 10.1016/j.jbiotec.2023.10.008 -
Methods in Molecular Biology (Clifton,... 2024Basic research and functional analyses of circular RNA (circRNA) have been limited by challenges in circRNA formation of desired length and sequence in adequate yields....
Basic research and functional analyses of circular RNA (circRNA) have been limited by challenges in circRNA formation of desired length and sequence in adequate yields. Nowadays, circular RNA can be obtained using enzymatic, "ribozymatic," or modulated splice events. However, there are few records for the directed circularization of RNA. Here, we present a proof of principle for an affordable and efficient RNA-based system for the controlled synthesis of circRNA with a physiological 3',5'-phosphodiester conjunction. The engineered hairpin ribozyme variant circular ribozyme 3 (CRZ-3) performs self-cleavage poorly. We designed an activator-polyamine complex to complete cleavage as a prerequisite for subsequent circularization. The developed protocol allows synthesizing circRNA without external enzymatic assistance and adds a controllable way of circularization to the existing methods.
Topics: RNA; RNA, Circular; Polyamines
PubMed: 38381342
DOI: 10.1007/978-1-0716-3678-7_12 -
Prostaglandins & Other Lipid Mediators Dec 2023Obesity is a non-communicable chronic disease that continues to increase around the world. Recently, it has been shown that curcumin positively affects lipid, energy...
Obesity is a non-communicable chronic disease that continues to increase around the world. Recently, it has been shown that curcumin positively affects lipid, energy metabolism, and body weight change. Moreover, polyamines are aliphatic polycations, which can be found in all mammalian cells and foods and have been shown to prevent obesity through many different mechanisms. However, whether the co-administration of curcumin and polyamines has synergistic effects has yet to be clarified. Our study aimed to examine the effects of curcumin and polyamines on obesity and to assess the changes in serum polyamine levels and tissue parameters. 28 Sprague-Dawley male rats were fed a high-fat diet for 10 weeks to develop obesity, and then they were randomly divided into 4 groups as the control group (CONT), curcumin group (CUR), polyamine group (POL), curcumin and polyamine group (CUR+POL) and supplements were administered for 6 weeks. As a result, the lowest feed consumption in rats was recorded in the CUR+POL group, and the group with the lowest weight after supplements was the POL group, then the CUR+POL, CONT, and CUR groups, respectively. N-acetyl putrescine and GABA levels increased significantly after obesity development. The total histopathological score in fat, liver, and kidney tissues increased significantly in the CONT group. In the CUR+POL group, damage to the tissues was in the direction of recovery compared to the other groups, and the expression of NF-κB was significantly low. These results suggest that combined curcumin and polyamines may have protective effects.
Topics: Rats; Male; Animals; Curcumin; Diet, High-Fat; Rats, Sprague-Dawley; Polyamines; Obesity; Mammals
PubMed: 37726052
DOI: 10.1016/j.prostaglandins.2023.106784