bims-polyam 2023-02-12 papers

bims-polyam

Biomed News

on Polyamines

Issue of 2023–02–12
seventeen papers selected by
Sebastian J. Hofer, University of Graz

The Sinorhizobium meliloti NspS-MbaA system affects biofilm formation, exopolysaccharide production and motility in response to specific polyamines.
Spermine oxidase induces DNA damage and sensitizes fusion negative rhabdomyosarcoma cells to irradiation.
p53 inhibits the Urea cycle and represses polyamine biosynthesis in glioma cell lines.
Escherichia coli YgiC and YjfC Possess Peptide─Spermidine Ligase Activity.
c-MYC-Driven Polyamine Metabolism in Ovarian Cancer: From Pathogenesis to Early Detection and Therapy.
Salivary Polyamines Help Detect High-Risk Patients with Pancreatic Cancer: A Prospective Validation Study.
Plant Peroxisomal Polyamine Oxidase: A Ubiquitous Enzyme Involved in Abiotic Stress Tolerance.
Pentafluoropropionic Anhydride Derivatization and GC-MS Analysis of Histamine, Agmatine, Putrescine, and Spermidine: Effects of Solvents and Starting Column Temperature.
Effects of Spermidine on Mouse Gut Morphology, Metabolites, and Microbial Diversity.
Evaluation of the Cytotoxic Effect of Pd2Spm against Prostate Cancer through Vibrational Microspectroscopies.
GUS Reporter-Aided Promoter Deletion Analysis of A. thaliana POLYAMINE OXIDASE 3.
Absence of Arabidopsis Polyamine Oxidase 5 Influences the Cytokinin-Induced Shoot Meristem Formation from Lateral Root Primordia.
Exogenous spermidine improved drought tolerance in Ilex verticillata seedlings.
Serum Metabolomics Reveals a Potential Benefit of Methionine in Type 1 Diabetes Patients with Poor Glycemic Control and High Glycemic Variability.
Determination of urinary spermine using controlled dissolution of polysulfide modified gold electrode.
Renal Ischemia Tolerance Mediated by eIF5A Hypusination Inhibition Is Regulated by a Specific Modulation of the Endoplasmic Reticulum Stress.
EIF5A2 specifically regulates the transcription of aging-related genes in human neuroblastoma cells.

Microbiology (Reading). 2023 Jan;169(1):

The Sinorhizobium meliloti NspS-MbaA system affects biofilm formation, exopolysaccharide production and motility in response to specific polyamines.

Víctor M Chávez-Jacobo, Víctor A Becerra-Rivera, Gabriela Guerrero, Michael F Dunn.

  We previously showed that specific polyamines (PAs) present in the extracellular environment markedly affect extracellular polysaccharide (EPS) production, biofilm formation and motility in Sinorhizobium meliloti Rm8530. We hypothesized that extracellular PA signals were sensed and transduced by the NspS and MbaA proteins, respectively, which are homologs of the PA-sensing, c-di-GMP modulating NspS-MbaA proteins described in Vibrio cholerae. Here we show that the decrease in biofilm formation and EPS production in the quorum-sensing (QS)-deficient S. meliloti wild-type strain 1021 in cultures containing putrescine or spermine did not occur in a 1021 nspS mutant (1021 nspS). The transcriptional expression of nspS in strain 1021 was significantly increased in cultures containing either of these polyamines, but not by exogenous cadaverine, 1,3-diaminopropane (DAP), spermidine (Spd) or norspermidine (NSpd). Cell aggregation in liquid cultures did not differ markedly between strain 1021 and 1021 nspS in the presence or absence of PAs. The S. meliloti QS-proficient Rm8530 wild-type and nspS mutant (Rm8530 nspS) produced similar levels of biofilm under control conditions and 3.2- and 2.2-fold more biofilm, respectively, in cultures with NSpd, but these changes did not correlate with EPS production. Cells of Rm8530 nspS aggregated from two- to several-fold more than the wild-type in cultures without PAs or in those containing Spm. NSpd, Spd and DAP differently affected swimming and swarming motility in strains 1021 and Rm8530 and their respective nspS mutants. nspS transcription in strain Rm8530 was greatly reduced by exogenous Spm. Bioinformatic analysis revealed similar secondary structures and functional domains in the MbaA proteins of S. meliloti and V. cholerae, while their NspS proteins differed in some residues implicated in polyamine recognition in the latter species. NspS-MbaA homologs occur in a small subset of soil and aquatic bacterial species that commonly interact with eukaryotes. We speculate that the S. meliloti NspS-MbaA system modulates biofilm formation, EPS production and motility in response to environmental or host plant-produced PAs.

Keywords:  NspS-MbaA ; S. meliloti; biofilm; cyclic di-GMP; exopolysaccharides; motility; polyamine sensing

DOI:  https://doi.org/10.1099/mic.0.001293
Front Cell Dev Biol. 2023 ;11 1061570

Spermine oxidase induces DNA damage and sensitizes fusion negative rhabdomyosarcoma cells to irradiation.

Clara Perrone, Silvia Pomella, Matteo Cassandri, Michele Pezzella, Stefano Giuliani, Tecla Gasperi, Antonella Porrazzo, Anna Alisi, Anna Pastore, Silvia Codenotti, Alessandro Fanzani, Giovanni Barillari, Libenzio Adrian Conti, Biagio De Angelis, Concetta Quintarelli, Paolo Mariottini, Franco Locatelli, Francesco Marampon, Rossella Rota, Manuela Cervelli.

  Rhabdomyosarcoma (RMS) is a pediatric myogenic soft tissue sarcoma that includes fusion-positive (FP) and fusion-negative (FN) molecular subtypes. FP-RMS expresses PAX3-FOXO1 fusion protein and often shows dismal prognosis. FN-RMS shows cytogenetic abnormalities and frequently harbors RAS pathway mutations. Despite the multimodal heavy chemo and radiation therapeutic regimens, high risk metastatic/recurrent FN-RMS shows a 5-year survival less than 30% due to poor sensitivity to chemo-radiotherapy. Therefore, the identification of novel targets is needed. Polyamines (PAs) such as putrescine (PUT), spermidine (SPD) and spermine (SPM) are low-molecular-mass highly charged molecules whose intracellular levels are strictly modulated by specific enzymes. Among the latter, spermine oxidase (SMOX) regulates polyamine catabolism oxidizing SPM to SPD, which impacts cellular processes such as apoptosis and DNA damage response. Here we report that low SMOX levels are associated with a worse outcome in FN-RMS, but not in FP-RMS, patients. Consistently, SMOX expression is downregulated in FN-RMS cell lines as compared to normal myoblasts. Moreover, SMOX transcript levels are reduced FN-RMS cells differentiation, being indirectly downregulated by the muscle transcription factor MYOD. Noteworthy, forced expression of SMOX in two cell lines derived from high-risk FN-RMS: 1) reduces SPM and upregulates SPD levels; 2) induces G0/G1 cell cycle arrest followed by apoptosis; 3) impairs anchorage-independent and tumor spheroids growth; 4) inhibits cell migration; 5) increases γH2AX levels and foci formation indicative of DNA damage. In addition, forced expression of SMOX and irradiation synergize at activating ATM and DNA-PKCs, and at inducing γH2AX expression and foci formation, which suggests an enhancement in DNA damage response. Irradiated SMOX-overexpressing FN-RMS cells also show significant decrease in both colony formation capacity and spheroids growth with respect to single approaches. Thus, our results unveil a role for SMOX as inhibitor of tumorigenicity of FN-RMS cells in vitro. In conclusion, our in vitro results suggest that SMOX induction could be a potential combinatorial approach to sensitize FN-RMS to ionizing radiation and deserve further in-depth studies.

Keywords:  DNA damage; SmOx; combination therapy; polyamine pathway; radioresistance; radiotherapy; rhabdomyosarcoma; soft tissue sarcoma

DOI:  https://doi.org/10.3389/fcell.2023.1061570
Metab Brain Dis. 2023 Feb 06.

p53 inhibits the Urea cycle and represses polyamine biosynthesis in glioma cell lines.

Yuhong Zhao, Yingxi Chen, Ling Wei, Jianhua Ran, Kejian Wang, Shujuan Zhu, Qian Liu.

  Glioma is the most common malignant tumor of the central nervous system. The urea cycle (UC) is an essential pathway to convert excess nitrogen and ammonia into the less toxic urea in humans. However, less is known about the functional significance of the urea cycle in glioma. p53 functions as a tumor suppressor and modulates several cellular functions and disease processes. In the present study, we aimed to explore whether p53 influences glioma progression by regulating the urea cycle. Here, we demonstrated the inhibitory impact of p53 on the expression of urea cycle enzymes and urea genesis in glioma cells. The level of polyamine, a urea cycle metabolite, was also regulated by p53 in glioma cells. Carbamoyl phosphate synthetase-1 (CPS1) is the first key enzyme involved in the urea cycle. Functionally, we demonstrated that CPS1 knockdown suppressed glioma cell proliferation, migration and invasion. Mechanistically, we demonstrated that the expression of ornithine decarboxylase (ODC), which determines the generation of polyamine, was regulated by CPS1. In addition, the impacts of p53 knockdown on ODC expression, glioma cell growth and aggressive phenotypes were significantly reversed by CPS1 inhibition. In conclusion, these results demonstrated that p53 inhibits polyamine metabolism by suppressing the urea cycle, which inhibits glioma progression.

Keywords:  Glioma; Ornithine decarboxylase; Polyamine; Urea cycle; p53

DOI:  https://doi.org/10.1007/s11011-023-01173-y
Biochemistry. 2023 Feb 06.

Escherichia coli YgiC and YjfC Possess Peptide─Spermidine Ligase Activity.

Jordan L Pederick, Jack Klose, Blagojce Jovcevski, Tara L Pukala, John B Bruning.

Polyamines and polyamine-containing metabolites are involved in many cellular processes related to bacterial cell growth and survival. In Escherichia coli, the bifunctional enzyme glutathionylspermidine synthetase/amidase (GspSA) controls the production of glutathionylspermidine, which has a protective role against oxidative stress. E. coli also encodes two enzymes with homology to the synthetase domain of GspSA, YgiC, and YjfC; however, these do not catalyze the formation of glutathionylspermidine, and their catalytic function remained unknown. Here, we detail the structural and functional characterization of YgiC and YjfC. Using X-ray crystallography, the high-resolution crystal structures of YgiC and YjfC were obtained. This revealed that YgiC and YjfC possess multiple substitutions in key residues required for binding of glutathione in GspSA. Despite this difference, these enzymes share a similar active site structure to GspSA, suggesting that they catalyze the formation of an alternate peptide─spermidine conjugate. As the physiological substrates of YgiC and YjfC are unknown, this was probed using the peptide triglycine as a model substrate. A combination of enzyme activity assays and mass spectrometry revealed that YgiC and YjfC can function as peptide-spermidine ligases, forming a triglycine-spermidine conjugate. For both enzymes, conjugate formation was only observed in the presence of spermidine, but not other common polyamines, supporting that spermidine or a spermidine derivative is the physiological substrate. Importantly, since YgiC and YjfC are widely distributed in Gram-negative bacterial species, this suggests that these enzymes function in a conserved cellular process, representing a currently unknown aspect of bacterial polyamine metabolism.

DOI: https://doi.org/10.1021/acs.biochem.2c00592
Cancers (Basel). 2023 Jan 19. pii: 623. [Epub ahead of print]15(3):

c-MYC-Driven Polyamine Metabolism in Ovarian Cancer: From Pathogenesis to Early Detection and Therapy.

Yihui Chen, Ricardo A León-Letelier, Ali Hussein Abdel Sater, Jody Vykoukal, Jennifer B Dennison, Samir Hanash, Johannes F Fahrmann.

  c-MYC and its paralogues MYCN and MYCL are among the most frequently amplified and/or overexpressed oncoproteins in ovarian cancer. c-MYC plays a key role in promoting ovarian cancer initiation and progression. The polyamine pathway is a bona fide target of c-MYC signaling, and polyamine metabolism is strongly intertwined with ovarian malignancy. Targeting of the polyamine pathway via small molecule inhibitors has garnered considerable attention as a therapeutic strategy for ovarian cancer. Herein, we discuss the involvement of c-MYC signaling and that of its paralogues in promoting ovarian cancer tumorigenesis. We highlight the potential of targeting c-MYC-driven polyamine metabolism for the treatment of ovarian cancers and the utility of polyamine signatures in biofluids for early detection applications.

Keywords:  MYC; early detection; ovarian cancer; polyamine; therapy

DOI:  https://doi.org/10.3390/cancers15030623
Int J Mol Sci. 2023 Feb 03. pii: 2998. [Epub ahead of print]24(3):

Salivary Polyamines Help Detect High-Risk Patients with Pancreatic Cancer: A Prospective Validation Study.

Daisuke Nose, Masahiro Sugimoto, Tsuneo Muta, Shin-Ichiro Miura.

  Pancreatic cancer is one of the most malignant cancer types and has a poor prognosis. It is often diagnosed at an advanced stage because of the absence of typical symptoms. Therefore, it is necessary to establish a screening method for the early detection of pancreatic cancer in high-risk individuals. This is a prospective validation study conducted in a cohort of 1033 Japanese individuals (male, n = 467, age = 63.3 ± 11.5 years; female, n = 566, age = 64.2 ± 10.6 years) to evaluate the use of salivary polyamines for screening pancreatic diseases and cancers. Patients with pancreatic cancer were not included; however, other pancreatic diseases were treated as positive cases for accuracy verification. Of the 135 individuals with elevated salivary polyamine markers, 66 had pancreatic diseases, such as chronic pancreatitis and pancreatic cysts, and 1 had gallbladder cancer. These results suggest that the salivary polyamine panel is a useful noninvasive pancreatic disease screening tool.

Keywords:  chronic pancreatitis; metabolomics; pancreatic cancer; polyamine; saliva

DOI:  https://doi.org/10.3390/ijms24032998
Plants (Basel). 2023 Feb 01. pii: 652. [Epub ahead of print]12(3):

Plant Peroxisomal Polyamine Oxidase: A Ubiquitous Enzyme Involved in Abiotic Stress Tolerance.

Ishita Samanta, Pamela Chanda Roy, Eshani Das, Sasmita Mishra, Gopal Chowdhary.

  Polyamines (PAs) are positively charged amines that are present in all organisms. In addition to their functions specific to growth and development, they are involved in responding to various biotic and abiotic stress tolerance functions. The appropriate concentration of PA in the cell is maintained by a delicate balance between the catabolism and anabolism of PAs, which is primarily driven by two enzymes, namely diamine oxidase and polyamine oxidase (PAO). PAOs have been found to be localized in multiple subcellular locations, including peroxisomes. This paper presents a holistic account of peroxisomal PAOs. PAOs are flavin adenine dinucleotide-dependent enzymes with varying degrees of substrate specificity. They are expressed differentially upon various abiotic stress conditions, namely heat, cold, salinity, and dehydration. It has also been observed that in a particular species, the various PAO isoforms are expressed differentially with a spatial and temporal distinction. PAOs are targeted to peroxisome via a peroxisomal targeting signal (PTS) type 1. We conducted an extensive bioinformatics analysis of PTS1s present in various peroxisomal PAOs and present a consensus peroxisome targeting signal present in PAOs. Furthermore, we also propose an evolutionary perspective of peroxisomal PAOs. PAOs localized in plant peroxisomes are of potential importance in abiotic stress tolerance since peroxisomes are one of the nodal centers of reactive oxygen species (ROS) homeostasis and an increase in ROS is a major indicator of the plant being in stress conditions; hence, in the future, PAO enzymes could be used as a key candidate for generating abiotic stress tolerant crops.

Keywords:  abiotic stress; evolution; peroxisome; polyamine oxidase; three-dimensional structure

DOI:  https://doi.org/10.3390/plants12030652
Molecules. 2023 Jan 17. pii: 939. [Epub ahead of print]28(3):

Pentafluoropropionic Anhydride Derivatization and GC-MS Analysis of Histamine, Agmatine, Putrescine, and Spermidine: Effects of Solvents and Starting Column Temperature.

Dimitrios Tsikas, Bibiana Beckmann, Svetlana Baskal, Gorig Brunner.

  Gas chromatography-mass spectrometry (GC-MS) is useful for the quantitative determination of the polyamines spermidine (SPD) and putrescine (PUT) and of the biogenic amine agmatine (AGM) in biological samples after derivatization. This GC-MS method involves a two-step extraction with n-butanol and hydrochloric acid, derivatization with pentafluoropropionic anhydride (PFPA) in ethyl acetate, and extraction of the pentafluoropropionic (PFP) derivatives by toluene of SPD, PUT, and AGM. We wanted to extend this GC-MS method for the biogenic amine histamine (HA), but we faced serious problems that did not allow reliable quantitative analysis of HA. In the present work, we addressed this issue and investigated the derivatization of HA and the effects of toluene and ethyl acetate, two commonly used water-insoluble organic solvents in GC-MS, and oven temperature program. Derivatization of unlabelled HA (d0-HA) and deuterium-labelled HA (d4-HA) with PFPA in ethyl acetate (PFPA-EA, 1:4, v/v; 30 min, 65 °C) resulted in the formation of d0-HA-(PFP)2 and d4-HA-(PFP)2 derivatives. d4-HA and 13C4-SPD were used as internal standards for the amines after standardization. Considerable quantitative effects of toluene and ethyl acetate were observed. The starting GC column temperature was also found to influence considerably the GC-MS analysis of HA. Our study shows the simultaneous quantitative analysis of HA as HA-(PFP)2, AGM as AGM-(PFP)3, PUT as PUT-(PFP)2, and SPD as SPD-(PFP)3 derivatives requires the use of ethyl acetate for their extraction and injection into the GC-MS apparatus and a starting GC column temperature of 40 °C instead of 70 °C. The PFP derivatives of HA, AGM, PUT, and SPD were found to be stable in ethyl acetate for several hours at room temperature. Analytically satisfactory linearity, precision, and accuracy were observed for HA, AGM, PUT, and SPD in biologically relevant ranges (0 to 700 pmol). The limits of detection of AGM, PUT, and SPD were about two times lower in ethyl acetate compared to toluene (range, 1-22 fmol). The limits of detection were 1670 fmol for d0-HA and 557 fmol for d4-HA. Despite the improvements achieved in the study for HA, its analysis by GC-MS as a PFP derivative is challenging and less efficient than that of PUT, AGM, and SPD.

Keywords:  GC column; GC-MS; acylation; amidation; amines; biogenic amines; derivatization; histamine; pentafluoropropionic anhydride; polyamines; solvent

DOI:  https://doi.org/10.3390/molecules28030939
Nutrients. 2023 Feb 01. pii: 744. [Epub ahead of print]15(3):

Effects of Spermidine on Mouse Gut Morphology, Metabolites, and Microbial Diversity.

Dong-Mei Jiang, Ze-Long Wang, Jia-Di Yang, Xin Wang, Chun-Yang Niu, Cheng-Weng Ji, Wei-Kang Ling, Xiao-Guang An, Yong-Ni Guo, Qian Sun, Lin Bai, De-Bing Li, Xiao-Hui Si, Bo Kang.

  Spermidine is a class of biologically active organic small molecules that play an important role in maintaining intestinal homeostasis. The specific objective of this study was to explore the effects of spermidine on intestinal morphology, metabolites, and microbial diversity in mice. We showed that 0.3 mmol/L of spermidine significantly promoted the growth of ileal villi (p < 0.05), and 3.0 mmol/L of spermidine significantly increased the body weight of mice and promoted the growth of jejunum villi (p < 0.05). The 16S rDNA sequencing results indicated that 3.0 mmol/L of spermidine affected the balance of the intestinal flora by increasing the abundance of intestinal Lactic acid bacteria and reducing the abundance of harmful bacteria (Turicibacter and Alistipes). Additionally, spermidine affects the levels of microbial metabolites such as succinic acid and Pantetheine. In summary, spermidine affects intestinal morphology and regulates intestinal flora and metabolites, and this study has provided a new understanding of spermidine's effects on the intestinal tract.

Keywords:  intestinal morphology; intestine; metabolite; microorganisms; spermidine

DOI:  https://doi.org/10.3390/nu15030744
Int J Mol Sci. 2023 Jan 18. pii: 1888. [Epub ahead of print]24(3):

Evaluation of the Cytotoxic Effect of Pd2Spm against Prostate Cancer through Vibrational Microspectroscopies.

Raquel C Laginha, Clara B Martins, Ana L C Brandão, Joana Marques, M Paula M Marques, Luís A E Batista de Carvalho, Inês P Santos, Ana L M Batista de Carvalho.

  Regarding the development of new antineoplastic agents, with a view to assess the selective antitumoral potential which aims at causing irreversible damage to cancer cells while preserving the integrity of their healthy counterparts, it is essential to evaluate the cytotoxic effects in both healthy and malignant human cell lines. In this study, a complex with two Pd(II) centers linked by the biogenic polyamine spermine (Pd2Spm) was tested on healthy (PNT-2) and cancer (LNCaP and PC-3) prostate human cell lines, using cisplatin as a reference. To understand the mechanisms of action of both cisplatin and Pd2Spm at a molecular level, Fourier Transform Infrared (FTIR) and Raman microspectroscopies were used. Principal component analysis was 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 impact. The main changes were observed between the B-DNA native conformation and either Z-DNA or A-DNA, with a higher effect on lipids having been detected in the presence of cisplatin as compared to Pd2Spm. In turn, the Pd-agent showed a more significant impact on proteins.

Keywords:  FTIR microspectroscopy; Raman microspectroscopy; cisplatin; palladium(II); prostate cancer

DOI:  https://doi.org/10.3390/ijms24031888
Int J Mol Sci. 2023 Jan 24. pii: 2317. [Epub ahead of print]24(3):

GUS Reporter-Aided Promoter Deletion Analysis of A. thaliana POLYAMINE OXIDASE 3.

Varvara Podia, Dimitris Chatzopoulos, Dimitra Milioni, Dimitrios J Stravopodis, Irene Dervisi, Andreas Roussis, Kalliopi A Roubelakis-Angelakis, Kosmas Haralampidis.

  Polyamine oxidases (PAOs) have been correlated with numerous physiological and developmental processes, as well as responses to biotic and abiotic stress conditions. Their transcriptional regulation is driven by signals generated by various developmental and environmental cues, including phytohormones. However, the inductive mechanism(s) of the corresponding genes remains elusive. Out of the five previously characterized Arabidopsis PAO genes, none of their regulatory sequences have been analyzed to date. In this study, a GUS reporter-aided promoter deletion approach was used to investigate the transcriptional regulation of AtPAO3 during normal growth and development as well as under various inductive environments. AtPAO3 contains an upstream open reading frame (uORF) and a short inter-cistronic sequence, while the integrity of both appears to be crucial for the proper regulation of gene expression. The full-length promoter contains several cis-acting elements that regulate the tissue-specific expression of AtPAO3 during normal growth and development. Furthermore, a number of TFBS that are involved in gene induction under various abiotic stress conditions display an additive effect on gene expression. Taken together, our data indicate that the transcription of AtPAO3 is regulated by multiple environmental factors, which probably work alongside hormonal signals and shed light on the fine-tuning mechanisms of PAO regulation.

Keywords:  Arabidopsis thaliana; GUS; PAO; TFBS; abiotic stress; abscisic acid; jasmonic acid; polyamines; promoter deletion analysis; salicylic acid

DOI:  https://doi.org/10.3390/ijms24032317
Plants (Basel). 2023 Jan 18. pii: 454. [Epub ahead of print]12(3):

Absence of Arabidopsis Polyamine Oxidase 5 Influences the Cytokinin-Induced Shoot Meristem Formation from Lateral Root Primordia.

Nikolett Kaszler, Péter Benkő, Árpád Molnár, Abigél Zámbori, Attila Fehér, Katalin Gémes.

  Lateral root primordia (LRPs) of Arabidopsis can be directly converted to shoot meristems (SMs) by the application of exogenous cytokinin. Here, we report that Arabidopsis POLYAMINE OXIDASE 5 (AtPAO5) contributes to this process, since the rate of SM formation from LRPs was significantly lower in the pao5-2 knockout mutant. Furthermore, the presented experiments showed that AtPAO5 influences SM formation via controlling the thermospermine (T-Spm) level. Gene expression analyses supported the view that the pao5-2 mutation as well as exogenous T-Spm downregulate the expression of the class 3 haemoglobin coding genes AtGLB1 and AtGLB2. AtGLB1 and 2 have been reported to augment cytokinin sensitivity, indirectly inhibiting the expression of type-A ARABIDOPSIS RESPONSE REGULATORs (ARRs). In agreement, the same ARR-coding genes were found to be upregulated in the pao5-2 mutant. Although GLB proteins might also control cytokinin-induced nitric oxide (NO) accumulation, we could not find experimental evidence for it. Rather, the negative effect of NO-donor treatment on AtPAO5 gene expression and SM formation was seen. Nevertheless, a hypothetical pathway is set up explaining how AtPAO5 may affect direct shoot meristem formation, controlling cytokinin sensitivity through T-Spm and GLBs.

Keywords:  Arabidopsis thaliana; cytokinin sensitivity; direct shoot regeneration; haemoglobins; nitric oxide; polyamine oxidase

DOI:  https://doi.org/10.3390/plants12030454
Front Plant Sci. 2023 ;14 1065208

Exogenous spermidine improved drought tolerance in Ilex verticillata seedlings.

Xiaoting Xie, Yujie Gu, Weili Wang, Farhat Abbas, Sini Qin, Siyi Fu, Jiaqi Mei, Jiayan Wang, Dexuan Ma, Guangchao Wen, Ying Yang, Anket Sharma, Xiaofei Wang, Daoliang Yan, Bingsong Zheng, Yi He, Huwei Yuan.

  Winterberry (Ilex verticillata (L.) A. Gray) is a recently introduced ornamental tree species in China that has not been closely investigated for its drought resistance. In this study, we used two-year-old cuttings from I. verticillata (L.) A. Gray and two representative varieties derived from it, I. verticillata 'Oosterwijk' and I. verticillata 'Jim Dandy', as materials to investigate how this plant responds to drought stress and whether exogenous spermidine (SPD) can alleviate the negative effects caused by drought stress. The results showed that as the degree of drought stress increased, the leaves of winterberry seedlings became chlorotic, and their edges became dry. Similarly, the relative water content, specific leaf weight, chlorophyll content, leaf nitrogen content, net photosynthetic rate, stomatal conductance and transpiration rate were significantly reduced, whereas the content of malondialdehyde continuously increased with the degree of drought stress. The activities of superoxide dismutase, peroxidase, and catalase increased under moderate drought stress and then decreased under severe drought stress. The levels of soluble sugar and abscisic acid continued to increase, while those of auxin and gibberellic acid decreased. When compared with individual drought stress, an increase in the amount of external SPD clearly alleviated the effect of drought stress on winterberry seedlings. The combined phenotypes and physiological indices of the winterberry leaves under drought stress conditions revealed that the drought resistance of the native species was significantly higher than its two varieties. This finding serves as an important theoretical foundation for the popularization and application of I. verticillata (L.) A. Gray and the two varieties.

Keywords:  Ilex verticillata; drought; physiological responses; spermidine; stress

DOI:  https://doi.org/10.3389/fpls.2023.1065208
Nutrients. 2023 Jan 19. pii: 518. [Epub ahead of print]15(3):

Serum Metabolomics Reveals a Potential Benefit of Methionine in Type 1 Diabetes Patients with Poor Glycemic Control and High Glycemic Variability.

Liyin Zhang, Keyu Guo, Qi Tian, Jianan Ye, Zhiyi Ding, Qin Zhou, Xia Li, Zhiguang Zhou, Lin Yang.

  Glycemic variability (GV) in some patients with type 1 diabetes (T1D) remains heterogeneous despite comparable clinical indicators, and whether other factors are involved is yet unknown. Metabolites in the serum indicate a broad effect of GV on cellular metabolism and therefore are more likely to indicate metabolic dysregulation associated with T1D. To compare the metabolomic profiles between high GV (GV-H, coefficient of variation (CV) of glucose ≥ 36%) and low GV (GV-L, CV < 36%) groups and to identify potential GV biomarkers, metabolomics profiling was carried out on serum samples from 17 patients with high GV, 16 matched (for age, sex, body mass index (BMI), diabetes duration, insulin dose, glycated hemoglobin (HbA1c), fasting, and 2 h postprandial C-peptide) patients with low GV (exploratory set), and another 21 (GV-H/GV-L: 11/10) matched patients (validation set). Subsequently, 25 metabolites were significantly enriched in seven Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between the GV-H and GV-L groups in the exploratory set. Only the differences in spermidine, L-methionine, and trehalose remained significant after validation. The area under the curve of these three metabolites combined in distinguishing GV-H from GV-L was 0.952 and 0.918 in the exploratory and validation sets, respectively. L-methionine was significantly inversely related to HbA1c and glucose CV, while spermidine was significantly positively associated with glucose CV. Differences in trehalose were not as reliable as those in spermidine and L-methionine because of the relatively low amounts of trehalose and the inconsistent fold change sizes in the exploratory and validation sets. Our findings suggest that metabolomic disturbances may impact the GV of T1D. Additional in vitro and in vivo mechanistic studies are required to elucidate the relationship between spermidine and L-methionine levels and GV in T1D patients with different geographical and nutritional backgrounds.

Keywords:  continuous glucose monitoring; glycemic variability; metabolomics; type 1 diabetes

DOI:  https://doi.org/10.3390/nu15030518
Mikrochim Acta. 2023 Feb 10. 190(3): 87

Determination of urinary spermine using controlled dissolution of polysulfide modified gold electrode.

Sanjeev Kumar Kannan, Subramani Esakkiappa, Esokkiya Anthonysamy, Sudalaimani Sudalaimuthu, Yusran Sulaiman, Mohammad Mansoob Khan, Jeyabharathi Chinnaiah, Giribabu Krishnan.

  Spermine (SPM) is considered a biomarker for prostate cancer and detecting it becomes highly challenging due to its electro- and optical-inactive nature. SPM has a tendency to interact with groups such as phosphates and sulfides to form macrocyclic arrangements known as nuclear aggregates of polyamines. Using this tendency, an electrochemical sensor has been developed using a polysulfide (PS) modified Au electrode (PS@Au electrode). PS has been synthesized from elemental sulfur by hydrothermal method and characterized using UV-Vis, fluorescence, FTIR, SEM, and XPS analyses. The PS@Au electrode was employed for electrochemical sensing of SPM. In the presence of SPM, a decrease in gold oxide reduction current was noted which is proportional to the concentration of SPM. The decrease in gold oxide reduction (0.5 V) current was attributed to the complexing nature of SPM-PS at the electrode interface. The reason for the decrease in current has been substantiated using XRF, XPS, and spectroelectrochemical studies. Under the optimized conditions, the PS@Au electrode exhibited a linear range of 1.55-250 µM with LOD of 0.511 ± 0.02 µM (3σ). The electrochemical strategy for SPM sensing exhibited better selectivity even in the presence of possible interferents. The selectivity stems from the selective interaction of SPM with PS on the Au electrode surface; the tested amino acids, and other molecules do not complex with PS and hence they could not interfere. The PS@Au electrode has been subjected to the determination of SPM in artificial urine samples and exhibited outstanding performance in the synthetic sample.

Keywords:  Au electrode; Non-enzymatic sensing; Polysulfides; Prostate cancer biomarker; Spermine; Square-wave voltammetry

DOI:  https://doi.org/10.1007/s00604-023-05664-8
Cells. 2023 Jan 25. pii: 409. [Epub ahead of print]12(3):

Renal Ischemia Tolerance Mediated by eIF5A Hypusination Inhibition Is Regulated by a Specific Modulation of the Endoplasmic Reticulum Stress.

Nicolas Melis, Isabelle Rubera, Sebastien Giraud, Marc Cougnon, Christophe Duranton, Mallorie Poet, Gisèle Jarretou, Raphaël Thuillier, Laurent Counillon, Thierry Hauet, Luc Pellerin, Michel Tauc, Didier F Pisani.

  Through kidney transplantation, ischemia/reperfusion is known to induce tissular injury due to cell energy shortage, oxidative stress, and endoplasmic reticulum (ER) stress. ER stress stems from an accumulation of unfolded or misfolded proteins in the lumen of ER, resulting in the unfolded protein response (UPR). Adaptive UPR pathways can either restore protein homeostasis or can turn into a stress pathway leading to apoptosis. We have demonstrated that N1-guanyl-1,7-diamineoheptane (GC7), a specific inhibitor of eukaryotic Initiation Factor 5A (eIF5A) hypusination, confers an ischemic protection of kidney cells by tuning their metabolism and decreasing oxidative stress, but its role on ER stress was unknown. To explore this, we used kidney cells pretreated with GC7 and submitted to either warm or cold anoxia. GC7 pretreatment promoted cell survival in an anoxic environment concomitantly to an increase in xbp1 splicing and BiP level while eiF2α phosphorylation and ATF6 nuclear level decreased. These demonstrated a specific modulation of UPR pathways. Interestingly, the pharmacological inhibition of xbp1 splicing reversed the protective effect of GC7 against anoxia. Our results demonstrated that eIF5A hypusination inhibition modulates distinctive UPR pathways, a crucial mechanism for the protection against anoxia/reoxygenation.

Keywords:  BiP; GC7; XBP1; anoxia; hypusine; kidney; preconditioning

DOI:  https://doi.org/10.3390/cells12030409
BMC Geriatr. 2023 Feb 07. 23(1): 83

EIF5A2 specifically regulates the transcription of aging-related genes in human neuroblastoma cells.

Yuwei Liu, Li Peng, Jing Chen, Ling Chen, Ying Wu, Mengxin Cheng, Min Chen, Xujun Ye, Yalei Jin.

   BACKGROUND: Post-transcriptional regulation plays a critical role in controlling biological processes such as aging. Previous studies have shown that eukaryotic initiation factor 5A (EIF5A) might play a crucial role in aging. It is unknown whether EIF5A2, a second isoform of EIF5A, could impact aging through post-transcriptional regulation.
METHODS: In the present study, EIF5A2 overexpression (EIF5A2-OE) was induced in SH-SY5Y cells. RNA-seq, bioinformatics analysis and RT-qPCR validation experiments were then performed to explore the molecular mechanism of EIF5A2-mediated transcriptional regulation. Cell viability, proportion of senescent cells and the cell cycle were respectively determined by Cell Counting Kit-8, SA-β‑galactosidase and flow cytometry to evaluate the cell senescence.
RESULTS: A total of 190 downregulated and 126 upregulated genes related to EIF5A2-OE were identified. Genes closely related to cellular aging processes such as unfolded protein response (UPR), cell adhesion and calcium signaling pathway were under global transcriptional regulation. Moreover, EIF5A2-OE promoted the viability of SH-SY5Y cells and reduced cell senescence in vitro. Among 30 genes with the most significant expression differences in EIF5A2-OE cells, we identified eight genes, including ASNS, ATF3, ATF4, CEBPB, DDIT3, HERPUD1, HSPA5 and XBP1, enriched in the UPR. Through EIF5A2-tanscription factors (TFs)-targets regulation network in EIF5A2-OE cells, we found three TFs, BHLHE40, RHOXF1 and TBX20, that targeted at these eight UPR-related genes. Verification test via the published database of human glial cell tissue showed only BHLHE40 and RHOXF1 were significantly associated with EIF5A2.
CONCLUSIONS: Our findings suggest that EIF5A2 may alleviate cell senescence in vitro and mediate UPR-related genes via specific TFs. Thus, EIF5A2 could function as a regulator of aging via the regulation of transcription, which greatly expands the current understanding of the mechanisms of EIF5A2-mediated gene regulation.

Keywords:  Aging; EIF5A2; RNA-seq; Transcription; Unfolded protein response

DOI:  https://doi.org/10.1186/s12877-023-03793-6