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Allantoin: A Potential Compound for the Mitigation of Adverse Effects of Abiotic Stresses in Plants.Plants (Basel, Switzerland) Aug 2023Stress-induced alterations vary with the species of plants, the intensity and duration of the exposure, and stressors availability in nature or soil. Purine catabolism... (Review)
Review
Stress-induced alterations vary with the species of plants, the intensity and duration of the exposure, and stressors availability in nature or soil. Purine catabolism acts as an inherent defensive mechanism against various abiotic stresses and plays a pivotal role in the stress acclimatisation of plants. The intermediate metabolite of purine catabolism, allantoin, compensates for soil nitrogen deficiency due to the low carbon/nitrogen ratio, thereby maintaining nitrogen homeostasis and supporting plant growth and development. Allantoin accounts for 90% of the total nitrogenous compound in legumes, while it contributes only 15% in non-leguminous plants. Moreover, studies on a variety of plant species have reported the differential accumulation of allantoin in response to abiotic stresses, endowing allantoin as a stress modulator. Allantoin functions as signalling molecule to stimulate stress-responsive genes (; pyrroline-5-carboxylase synthase) and ROS (reactive oxygen species) scavenging enzymes (antioxidant). Moreover, it regulates cross-talk between the abscisic acid and jasmonic acid pathway, and maintains ion homeostasis by increasing the accumulation of putrescine and/or spermine, consequently enhancing the tolerance against stress conditions. Further, key enzymes of purine catabolism (xanthine dehydrogenase and allantoinase) have also been explored by constructing various knockdown/knockout mutant lines to decipher their impact on ROS-mediated oxidative injury in plants. Thus, it is established that allantoin serves as a regulatory signalling metabolite in stress protection, and therefore a lower accumulation of allantoin also reduces plant stress tolerance mechanisms. This review gives an account of metabolic regulation and the possible contribution of allantoin as a photo protectant, osmoprotectant, and nitrogen recycler to reduce abiotic-stress-induced impacts on plants.
PubMed: 37687306
DOI: 10.3390/plants12173059 -
EMBO Molecular Medicine Nov 2023Snyder-Robinson syndrome (SRS) is a rare genetic disorder characterized by intellectual disability and delayed development beginning early in childhood. It was first...
Snyder-Robinson syndrome (SRS) is a rare genetic disorder characterized by intellectual disability and delayed development beginning early in childhood. It was first described in a single family in 1969 as a sex-linked disorder (Snyder & Robinson, 1969) and has since been only identified in less than 100 individuals worldwide. Inherited in an X-linked recessive pattern, SRS has only been identified in males thus far. Snyder-Robinson syndrome primarily affects the nervous system and skeletal tissues and is caused by loss-of-function mutations in the gene encoding spermine synthase (SMS), a polyamine biosynthesis enzyme. Affected males display a collection of clinical features including intellectual disability ranging from mild to profound, speech and vision impairment, osteoporosis, hypotonia, and increasing loss of muscle tissue with age, kyphoscoliosis, seizures, and distinctive facial features including a prominent lower lip and facial asymmetry. Currently, there is no cure or treatment for this debilitating disorder aside from symptom management.
Topics: Male; Humans; Polyamines; Intellectual Disability; Mental Retardation, X-Linked; Mutation; Sulfadiazine
PubMed: 37712293
DOI: 10.15252/emmm.202318506 -
Proceedings of the National Academy of... Apr 2024Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully...
Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully understood. In this study, we investigated the role of MUC1, a mucin protein overexpressed in pancreatic cancer, in regulating polyamine metabolism. Utilizing pancreatic cancer patient data, we noted a positive correlation between MUC1 expression and the expression of key polyamine metabolism pathway genes. Functional studies revealed that knockdown of spermidine/spermine N1-acetyltransferase 1 (), a key enzyme involved in polyamine catabolism, attenuated the oncogenic functions of MUC1, including cell survival and proliferation. We further identified a regulatory axis whereby MUC1 stabilized hypoxia-inducible factor (HIF-1α), leading to increased SAT1 expression, which in turn induced carbon flux into the tricarboxylic acid cycle. MUC1-mediated stabilization of HIF-1α enhanced the promoter occupancy of the latter on promoter and corresponding transcriptional activation of , which could be abrogated by pharmacological inhibition of HIF-1α or CRISPR/Cas9-mediated knockout of . knockdown caused a significant reduction in the levels of SAT1-generated metabolites, N1-acetylspermidine and N8-acetylspermidine. Given the known role of MUC1 in therapy resistance, we also investigated whether inhibiting SAT1 would enhance the efficacy of FOLFIRINOX chemotherapy. By utilizing organoid and orthotopic pancreatic cancer mouse models, we observed that targeting SAT1 with pentamidine improved the efficacy of FOLFIRINOX, suggesting that the combination may represent a promising therapeutic strategy against pancreatic cancer. This study provides insights into the interplay between MUC1 and polyamine metabolism, offering potential avenues for the development of treatments against pancreatic cancer.
Topics: Mice; Animals; Humans; Antineoplastic Combined Chemotherapy Protocols; Pancreatic Neoplasms; Polyamines; Signal Transduction; Acetyltransferases; Mucin-1
PubMed: 38547055
DOI: 10.1073/pnas.2315509121 -
BioRxiv : the Preprint Server For... Mar 2024Mitochondrial (Mito) dysfunction in IBD reduces mucosal O2 consumption and increases O2 delivery to the microbiome. Increased enteric O2 promotes blooms of facultative...
BACKGROUND
Mitochondrial (Mito) dysfunction in IBD reduces mucosal O2 consumption and increases O2 delivery to the microbiome. Increased enteric O2 promotes blooms of facultative anaerobes (eg. ) and restricts obligate anaerobes (eg. ). Dysbiotic metabolites negatively affect host metabolism and immunity. Our novel compound (AuPhos) upregulates intestinal epithelial cell (IEC) mito function, attenuates colitis and corrects dysbiosis in humanized mice. We posit that AuPhos corrects IBD-associated dysbiotic metabolism.
METHODS
Primary effect of AuPhos on mucosal Mito respiration and healing process was studied in ex vivo treated human colonic biopsies and piroxicam-accelerated (Px) mice. Secondary effect on microbiome was tested in DSS-colitis WT B6 and germ-free 129.SvEv WT or mice reconstituted with human IBD stool (Hu- ). Mice were treated orally with AuPhos (10- or 25- mg/kg; q3d) or vehicle, stool samples collected for fecal lipocalin-2 (f-LCN2) assay and microbiome analyses using 16S rRNA sequencing. AuPhos effect on microbial metabolites was determined using untargeted global metabolomics. AuPhos-induced hypoxia in IECs was assessed by Hypoxyprobe-1 staining in sections from pimonidazole HCl-infused DSS-mice. Effect of AuPhos on enteric oxygenation was assessed by (aerobic respiration-proficient) and mutant (aerobic respiration-deficient).
RESULTS
Metagenomic (16S) analysis revealed AuPhos reduced relative abundances of and increased blooms of in uninflamed B6 WT, DSS-colitis, Hu-WT and Hu- mice. AuPhos also increased hypoxyprobe-1 staining in surface IECs suggesting enhanced O2 utilization. AuPhos-induced anaerobiosis was confirmed by a significant increase in cydA mutant compared to WT (O2-utlizing) . Ex vivo treatment of human biopsies with AuPhos showed significant increase in Mito mass, and complexes I and IV. Further, gene expression analysis of AuPhos-treated biopsies showed increase in stem cell markers (Lgr4, Lgr5, Lrig1), with concomitant decreases in pro-inflammatory markers (IL1β,MCP1, RankL). Histological investigation of AuPhos-fed Px- mice showed significantly decreased colitis score in AuPhos-treated Px- mice, with decrease in mRNA of pro-inflammatory cytokines and increase in Mito complexes ( , ). AuPhos significantly altered microbial metabolites associated with SCFA synthesis, FAO, TCA cycle, tryptophan and polyamine biosynthesis pathways. AuPhos increased pyruvate, 4-hydroxybutyrate, 2-hydroxyglutarate and succinate, suggesting an upregulation of pyruvate and glutarate pathways of butyrate production. AuPhos reduced IBD-associated primary bile acids (BA) with concomitant increase in secondary BA (SBA). AuPhos treatment significantly decreased acylcarnitines and increased L-carnitine reflective of enhanced FAO. AuPhos increases TCA cycle intermediates and creatine, energy reservoir substrates indicating enhanced OxPHOS. Besides, AuPhos also upregulates tryptophan metabolism, decreases Kynurenine and its derivatives, and increases polyamine biosynthesis pathway (Putresceine and Spermine).
CONCLUSION
These findings indicate that AuPhos-enhanced IEC mitochondrial function reduces enteric O2 delivery, which corrects disease-associated metabolomics by restoring short-chain fatty acids, SBA, AA and IEC energy metabolism.
PubMed: 38559035
DOI: 10.1101/2024.03.14.584471 -
Cell Reports Dec 2023The retrosplenial cortex (RSC) is a vital area for storing remote memory and has recently been found to undergo broad changes after peripheral nerve injury. However,...
The retrosplenial cortex (RSC) is a vital area for storing remote memory and has recently been found to undergo broad changes after peripheral nerve injury. However, little is known about the role of RSC in pain regulation. Here, we examine the involvement of RSC in the pain of mice with nerve injury. Notably, reducing the activities of calcium-/calmodulin-dependent protein kinase type II-positive splenial neurons chemogenetically increases paw withdrawal threshold and extends thermal withdrawal latency in mice with nerve injury. The single-cell or single-nucleus RNA-sequencing results predict enhanced excitatory synaptic transmissions in RSC induced by nerve injury. Local infusion of 1-naphthyl acetyl spermine into RSC to decrease the excitatory synaptic transmissions relieves pain and induces conditioned place preference. Our data indicate that RSC is critical for regulating physiological and neuropathic pain. The cell type-dependent transcriptomic information would help understand the molecular basis of neuropathic pain.
Topics: Mice; Animals; Gyrus Cinguli; Peripheral Nerve Injuries; Neurons; Gene Expression Profiling; Neuralgia
PubMed: 38048224
DOI: 10.1016/j.celrep.2023.113551 -
Brazilian Journal of Biology = Revista... 2023Small fruits such as strawberries, are a good source of natural antioxidants. In recent decades, many efforts have been made to increase the shelf life of strawberries...
Small fruits such as strawberries, are a good source of natural antioxidants. In recent decades, many efforts have been made to increase the shelf life of strawberries and maintain its nutritional value in post-harvest conditions. In the present study, the effects of spermine (Spm) and spermidine (Spd) (0, 1.0 and 1.5 mM) on the post-harvest life and quality of strawberry fruits during the 3rd, 6th, and 12th days of storage, were investigated. Applications of Spm and Spd decreased the rate of weight loss, fruit decay, soluble solids content, fruit juice pH and taste index during the storage period in compared to the control. However, titratable acids and vitamin C contents, tissue stiffness, phenolic compounds and antioxidant activity increased in compared to the control. These growth regulators prevented the aging and loss of bioactive compounds of the fruit by increasing the antioxidant activity and preventing the destruction of the fruit tissue. Among the studied treatments, applications of 1.5 mM of Spm and Spd were the most effective treatments to enhance the storage life and quality characters of strawberry fruits.
Topics: Spermidine; Spermine; Antioxidants; Fruit; Fragaria
PubMed: 37851771
DOI: 10.1590/1519-6984.273886 -
Antioxidants (Basel, Switzerland) Aug 2023Autophagy is a highly conserved process that degrades damaged macromolecules and organelles. Unlike animals, only scant information is available regarding nitric oxide...
Autophagy is a highly conserved process that degrades damaged macromolecules and organelles. Unlike animals, only scant information is available regarding nitric oxide (NO)-induced autophagy in plants. Such lack of information prompted us to study the roles of the NO donors' nitrate, nitrite, and sodium nitroprusside in this catabolic process in wheat roots. Furthermore, spermine, a polyamine that is found in all eukaryotic cells, was also tested as a physiological NO donor. Here, we show that in wheat roots, NO donors and spermine can trigger autophagy, with NO and reactive oxygen species (ROS) playing signaling roles based on the visualization of autophagosomes, analyses of the levels of NO, ROS, mitochondrial activity, and the expression of autophagic () genes. Treatment with nitrite and nitroprusside causes an energy deficit, a typical prerequisite of autophagy, which is indicated by a fall in mitochondrial potential, and the activity of mitochondrial complexes. On the contrary, spermine sustains energy metabolism by upregulating the activity of appropriate genes, including those that encode glyceraldehyde 3-phosphate dehydrogenase GAPDH and SNF1-related protein kinase 1 SnRK1. Taken together, our data suggest that one of the key roles for NO in plants may be to trigger autophagy via diverse mechanisms, thus facilitating the removal of oxidized and damaged cellular constituencies.
PubMed: 37759958
DOI: 10.3390/antiox12091655 -
Balkan Medical Journal Sep 2023The main pathological feature of diabetic cardiomyopathy (DCM) caused by diabetes mellitus is myocardial fibrosis. According to recent studies in cardiology, it has been...
BACKGROUND
The main pathological feature of diabetic cardiomyopathy (DCM) caused by diabetes mellitus is myocardial fibrosis. According to recent studies in cardiology, it has been suggested that spermidine (SPD) has cardioprotective properties.
AIMS
To explore the role and mechanism of SPD in alleviating myocardial fibrosis of DCM.
STUDY DESIGN
In vivo and in vitro study.
METHODS
Type 2 diabetic mice and primary neonatal mouse cardiac fibroblasts (CFs) were selected. Measurements of serum-related markers, echocardiographic analysis, and immunohistochemistry were used to evaluate myocardial fibrosis injury and the effects of SPD. The proliferation and migration of CFs undergoing different treatments were studied. Immunoblotting and real-time quantitative reverse transcription polymerase chain reaction were used to demonstrate molecular mechanisms.
RESULTS
In vivo immunoblotting analysis indicated a downregulation of ornithine decarboxylase and an upregulation of SPD/spermine N1-acetyltransferase. We observed cardiac dysfunction in diabetic mice after 12 weeks. However, the administration of exogenous SPD improved cardiac function, decreased collagen deposition, and reduced myocardial tissue damage. mRNA expression levels of NLRP3, Caspase-1, GSDMD-N, interleukin (IL)-1β, IL-17A, and IL-18 were increased and suppressed in the myocardium of db/db mice upon treatment with SPD. SPD inhibited the proliferation, migration, and collagen secretion of high-glucose-treated fibroblasts in vitro. SPD inhibits the activation of the TGF-β1/Smad signaling pathway and decreases collagen deposition by reducing pyroptosis and Smad-7 ubiquitination levels.
CONCLUSION
Based on our findings, SPD may have potential applications in protecting against the deterioration of cardiac function in patients with DCM due to a significant new mechanism for diabetic myocardial fibrosis that we discovered.
Topics: Mice; Animals; Spermidine; Pyroptosis; Diabetes Mellitus, Experimental; Diabetic Cardiomyopathies; Collagen; Inflammation; Fibrosis
PubMed: 37350700
DOI: 10.4274/balkanmedj.galenos.2023.2023-3-102 -
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 -
Journal of Molecular Graphics &... Jul 2023Ongoing global pandemic caused by coronavirus (COVID-19) requires urgent development of vaccines, treatments, and diagnostic tools. Open reading frame 3a (ORF3a) from...
Ongoing global pandemic caused by coronavirus (COVID-19) requires urgent development of vaccines, treatments, and diagnostic tools. Open reading frame 3a (ORF3a) from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is considered to be a potential drug target for COVID-19 treatment. ORF3a is an accessory protein that plays a significant role in virus-host interactions and in facilitating host immune responses. Using putrescine, spermidine and spermine, an aliphatic polyamine for the activity suppression of ORF3a appears to be a promising approach in finding new targets for drug design. In this study, we explored the possible binding poses of polyamines to the ORF3a protein using a combination of various computational approaches i.e. pocket prediction, blind and site-specific molecular docking, molecular dynamics and ligand flooding simulations. The results showed that the tip of cytoplasmic domain and the upper tunnel of transmembrane domain of ORF3a provide a suitable binding site specific for the polyamines. MD simulations revealed the stability of spermidine binding in the upper tunnel pocket of ORF3a through salt bridge and hydrogen bond interactions between the amine groups of the ligand and negatively charged residues of ORF3a. These findings can be helpful in designing new therapeutic drugs.
Topics: Humans; SARS-CoV-2; COVID-19; Molecular Docking Simulation; Polyamines; Open Reading Frames; Spermidine; COVID-19 Drug Treatment; Ligands
PubMed: 37086515
DOI: 10.1016/j.jmgm.2023.108487