RESUMEN

Ensuring the homeostatic integrity of pulmonary artery endothelial cells (PAECs) is essential for combatting pulmonary arterial hypertension (PAH), as it equips the cells to withstand microenvironmental challenges. Spermidine (SPD), a potent facilitator of autophagy, has been identified as a significant contributor to PAECs function and survival. Despite SPD's observed benefits, a comprehensive understanding of its protective mechanisms has remained elusive. Through an integrated approach combining metabolomics and molecular biology, this study uncovers the molecular pathways employed by SPD in mitigating PAH induced by monocrotaline (MCT) in a Sprague-Dawley rat model. The study demonstrates that SPD administration (5 mg/kg/day) significantly corrects right ventricular impairment and pathological changes in pulmonary tissues following MCT exposure (60 mg/kg). Metabolomic profiling identified a purine metabolism disorder in MCT-treated rats, which SPD effectively normalized, conferring a protective effect against PAH progression. Subsequent in vitro analysis showed that SPD (0.8 mM) reduces oxidative stress and apoptosis in PAECs challenged with Dehydromonocrotaline (MCTP, 50 µM), likely by downregulating purine nucleoside phosphorylase (PNP) and modulating polyamine biosynthesis through alterations in S-adenosylmethionine decarboxylase (AMD1) expression and the subsequent production of decarboxylated S-adenosylmethionine (dcSAM). These findings advocate SPD's dual inhibitory effect on PNP and AMD1 as a novel strategy to conserve cellular ATP and alleviate oxidative injuries, thus providing a foundation for SPD's potential therapeutic application in PAH treatment.

Asunto(s)

Células Endoteliales , Monocrotalina , Poliaminas , Hipertensión Arterial Pulmonar , Arteria Pulmonar , Purinas , Ratas Sprague-Dawley , Espermidina , Remodelación Vascular , Animales , Espermidina/farmacología , Espermidina/uso terapéutico , Purinas/farmacología , Poliaminas/metabolismo , Masculino , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Remodelación Vascular/efectos de los fármacos , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/metabolismo , Arteria Pulmonar/patología , Ratas , Hipertensión Arterial Pulmonar/tratamiento farmacológico , Hipertensión Arterial Pulmonar/inducido químicamente , Hipertensión Arterial Pulmonar/metabolismo , Células Cultivadas , Estrés Oxidativo/efectos de los fármacos , Apoptosis/efectos de los fármacos , Purina-Nucleósido Fosforilasa/metabolismo , Hipertensión Pulmonar/tratamiento farmacológico , Hipertensión Pulmonar/inducido químicamente , Hipertensión Pulmonar/metabolismo , Adenosilmetionina Descarboxilasa/metabolismo , Modelos Animales de Enfermedad , Humanos

RESUMEN

Tissue damage dramatically alters how cells interact with their microenvironment. These changes in turn dictate cellular responses, such as stem cell activation, yet early cellular responses in vivo remain ill defined. We generated single-cell and nucleus atlases from intact, dissociated, and injured muscle and liver and identified a common stress response signature shared by multiple cell types across these organs. This prevalent stress response was detected in published datasets across a range of tissues, demonstrating high conservation but also a significant degree of data distortion in single-cell reference atlases. Using quiescent muscle stem cells as a paradigm of cell activation following injury, we captured early cell activation following muscle injury and found that an essential ERK1/2 primary proliferation signal precedes initiation of the Notch-regulated myogenic program. This study defines initial events in response to tissue perturbation and identifies a broadly conserved transcriptional stress response that acts in parallel with cell-specific adaptive alterations.

Asunto(s)

Células Satélite del Músculo Esquelético , Proliferación Celular , Desarrollo de Músculos , Músculos , Células Madre

RESUMEN

A recent paper in Bioscience Reports (BSR20182189) describes the discovery of an interaction between the motor protein myosin Va and the metabolic enzyme spermine synthase. Myosin Va is a molecular motor which plays a key role in vesicle transport. Mutations in the gene which encodes this protein are associated with Griscelli syndrome type 1 and the 'dilute' phenotype in animals. Spermine synthase catalyzes the conversion of spermidine to spermine. This largely cytoplasmic enzyme can also be localized to the soluble fraction in exosomes. Mutations in the spermine synthase gene are associated with Snyder Robinson mental retardation syndrome. The interaction between the two proteins was detected using the yeast two hybrid method and verified by microscale thermophoresis of recombinant proteins. Knockdown of the MYO5A gene reduced the expression of mRNA coding for spermine synthase. The amount of this transcript was also reduced in cells derived from a patient with Griscelli syndrome type 1. This suggests that, in addition to a direct physical interaction between the two proteins, myosin Va also modulates the transcription of the spermine synthase gene. The mechanism for this modulation is currently unknown. These findings have implications for Griscelli syndrome type 1 and Snyder Robinson mental retardation syndrome. They also suggest that interactions between myosin Va and soluble exosome proteins such as spermine synthase may be important in the mechanism of exosome transport.

Asunto(s)

Exosomas , Discapacidad Intelectual Ligada al Cromosoma X/genética , Animales , Humanos , Espermidina , Espermina , Espermina Sintasa/genética

RESUMEN

In aquaculture production, studies of salmon health and interaction between pathogens and nutrition are of high importance. This study aimed to compare genes and pathways involved in salmon head kidney cells and liver cells, isolated from the same fish, towards polyinosinic acid: polycytidylic acid (poly I:C) and lipopolysaccharide (LPS), with and without addition of surplus arginine. Selected transcriptional responses of genes involved in inflammation, polyamine synthesis, oxidation and apoptosis were elucidated. For the genes related to inflammation, viperin, Mx and Toll like receptor 3 (TLR3), transcription were significantly upregulated by poly I:C in head kidney cells, while viperin was upregulated in liver cells. Surplus arginine did not affect poly I:C induced responses with the exception of reducing poly I:C induced Mx transcription in head kidney cells. Gene transcription of Interleukin 1ß (IL-1ß), Interleukin-8 (IL-8) and cyclooxygenase 2 (Cox2) were elevated during LPS treatment in all liver and head kidney cell cultures. In addition, LPS induced significantly, CD83 transcription in liver cells and TNF-α transcription in head kidney cells. Surplus arginine significantly reduced IL-8, Cox2 and TNF-α transcription in head kidney cells. LPS upregulated arginase in head kidney cells while poly I:C upregulated S-adenosyl methionine decarboxylase (SAMdc) transcription in liver cells. This suggests that LPS and poly I:C modulates genes involved in polyamine synthesis. In addition, in head kidney cells, surplus arginine, when cultured together with LPS, increased the transcription of ornithine decarboxylase (ODC) the limiting enzyme of polyamine synthesis. The genes involved with oxidation and apoptosis were not affect by any of the treatments in liver cells, while LPS decreased caspase 3 transcription in head kidney cells. In liver cells, protein expression of catalase was reduced by surplus arginine alone and when challenged with poly I:C. Both liver cells and head kidney cells isolated from the same individual fish responded to LPS and poly I:C, depending on the gene analyzed. Additionally, arginine could modulate transcription of pro-inflammatory genes induced by LPS in salmon immune cells, thus affecting salmon immunity.

Asunto(s)

Arginina/metabolismo , Riñón Cefálico/metabolismo , Lipopolisacáridos/farmacología , Poli I-C/farmacología , Salmo salar/metabolismo , Animales , Apoptosis/genética , Arginina/administración & dosificación , Células Cultivadas , Regulación de la Expresión Génica , Riñón Cefálico/efectos de los fármacos , Inflamación/genética , Inflamación/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Oxidación-Reducción , Poliaminas/metabolismo , Salmo salar/genética

RESUMEN

Polyamines (PAs), including putrescine (Put), spermidine (Spd), spermine (Spm), and thermospermine (T-Spm), play key roles in plant development, including fruit setting and ripening, morphogenesis, and abiotic/biotic stress. Their functions appear to be intimately related to their synthesis, which occurs via arginine/ornithine decarboxylase (ADC/ODC), Spd synthase (SPDS), Spm synthase (SPMS), and Acaulis5 (ACL5), respectively. Unfortunately, the expression and function of these PA synthesis-relate genes during specific developmental process or under stress have not been fully elucidated. Here, we present the results of a genome-wide analysis of the PA synthesis genes (ADC, ODC, SPDS, SPMS, ACL5) in the tomato (Solanum lycopersicum). In total, 14 PA synthesis-related genes were identified. Further analysis of their structures, conserved domains, phylogenetic trees, predicted subcellular localization, and promoter cis-regulatory elements were analyzed. Furthermore, we also performed experiments to evaluate their tissue expression patterns and under hormone and various stress treatments. To our knowledge, this is the first study to elucidate the mechanisms underlying PA function in this variety of tomato. Taken together, these data provide valuable information for future functional characterization of specific genes in the PA synthesis pathway in this and other plant species. Although additional research is required, the insight gained by this and similar studies can be used to improve our understanding of PA metabolism ultimately leading to more effective and consistent plant cultivation.

Asunto(s)

Genoma de Planta , Filogenia , Poliaminas/metabolismo , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Transcriptoma , Frutas/genética , Frutas/metabolismo , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Genómica/métodos , Solanum lycopersicum/clasificación , Redes y Vías Metabólicas/genética , Putrescina/metabolismo , Estrés Fisiológico/genética

RESUMEN

Dwarfism and drought tolerance are 2 valuable traits in breeding of many crops. In this study, we report the novel physiological roles of cholesterol in regulation of plant growth and drought tolerance. Compared with the wild type, sterol-C24-methyltransferase 1 (SMT1) gene transcript was greatly reduced in a bermudagrass mutant with dwarfism and enhanced drought tolerance, accompanied with cholesterol accumulation, elevated transcript levels of a small group of genes including SAMDC, and increased concentrations of putrescine (Put), spermidine (Spd), and spermine (Spm). Knock-down of OsSMT1 expression by RNA interference resulted in similar phenotypic changes in transgenic rice. Moreover, exogenously applied cholesterol also led to elevated transcripts of a similar set of genes, higher levels of Put, Spd, and Spm, improved drought tolerance, and reduced plant height in both bermudagrass and rice. We revealed that it is Spm, but not Spd, that is responsible for the height reduction in bermudagrass and rice. In conclusion, we suggest that cholesterol induces expression of SAMDC and leads to dwarfism and elevated drought tolerance in plants as a result of the promoted Spd and Spm synthesis.

Asunto(s)

Adaptación Fisiológica , Colesterol/metabolismo , Cynodon/anatomía & histología , Sequías , Oryza/anatomía & histología , Oryza/fisiología , Proteínas de Plantas/metabolismo , Supresión Genética , Adaptación Fisiológica/genética , Cynodon/genética , Cynodon/fisiología , Regulación hacia Abajo/genética , Regulación de la Expresión Génica de las Plantas , Mutación/genética , Oryza/genética , Plantas Modificadas Genéticamente , Poliaminas/metabolismo , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo

RESUMEN

Putrescine, 1,4-diaminobutane, is an intermediate in the biosynthesis of more complexed polyamines, spermidine and spermine. Unlike other eukaryotes, plants have evolved a multistep pathway for putrescine biosynthesis that utilizes arginine. In the final reaction, N-carbamoylputrescine is hydrolyzed to putrescine by N-carbamoylputrescine amidohydrolase (CPA, EC 3.5.1.53). During the hydrolysis, consecutive nucleophilic attacks on the substrate by Cys158 and water lead to formation of putrescine and two by-products, ammonia and carbon dioxide. CPA from the model legume plant, Medicago truncatula (MtCPA), was investigated in this work. Four crystal structures were determined: the wild-type MtCPA in complex with the reaction intermediate, N-(dihydroxymethyl)putrescine as well as with cadaverine, which is a longer analog of putrescine; and also structures of MtCPA-C158S mutant unliganded and with putrescine. MtCPA assembles into octamers, which resemble an incomplete left-handed helical twist. The active site of MtCPA is funnel-like shaped, and its entrance is walled with a contribution of the neighboring protein subunits. Deep inside the catalytic cavity, Glu48, Lys121, and Cys158 form the catalytic triad. In this studies, we have highlighted the key residues, highly conserved among the plant kingdom, responsible for the activity and selectivity of MtCPA toward N-carbamoylputrescine. Moreover, since, according to previous reports, a close MtCPA relative from Arabidopsis thaliana, along with several other nitrilase-like proteins, are subjected to allosteric regulation by substrates, we have used the structural information to indicate a putative secondary binding site. Based on the docking experiment, we postulate that this site is adjacent to the entrance to the catalytic pocket.

RESUMEN

Rapid tumor cell growth depends on intracellular polyamine levels higher than those of normal cells. Intracellular polyamine depletion inhibits tumor cell proliferation and induces tumor cell apoptosis. Therefore, polyamine metabolism has recently been identified as an important target for anti-tumor therapy. This article briefly summarizes recent polyamine metabolism targeting, polyamine depletion within the tumor cells through a variety of methods, and the antitumor effects of the treatment.