Maternal supplementation spermidine during gestation improves placental angiogenesis and reproductive performance of high prolific sows

Spermidine (SPD) is a widely recognized polyamine compound found in mammalian cells and plays a key role in various cellular processes. We propose that SPD may enhance placental vascular development in pregnant sows, leading to increased birth weight of piglets. Six hundred and nine sows at 60 days of gestation were randomly assigned into a basal diet (CON group), basal diet supplemented 10 mg/kg of SPD (SPD1 group), and basal diet supplemented 20 mg/kg of SPD (SPD2 group), respectively. Compared with the CON, SPD1 significantly increased the average number of healthy piglets per litter and the placental efficiency (P < .05), while the average number of mummified fetus per litter and the percentage of weak piglets significantly decreased (P < .05). In the plasma metabolomics, SPD content in plasma of sows (P = .075) and umbilical cord plasma of piglets (P = .078) had an increasing trend in response to SPD1. Furthermore, SPD1 increased the expression of the vascular endothelial cell marker protein, platelet endothelial cell adhesionmolecule-1 (PECAM-1/CD31) and the density of placental stromal vessels (P < .05). Moreover, as compared to CON, SPD2 significantly decreased the average number of mummified fetus per litter (P < .05), while the placental efficiency and the expression of amino acid transporter solute carrier (SLC) family 7, member7 (SLC7A7) and glucose transporters SLC2A2) and SLC5A4 in placental tissue significantly increased (P < .05). These results suggest that maternal supplementation of SPD during pregnancy increased healthy litter number, and promoted placental tissue development. Our findings provide evidence that maternal SPD has the potential to improve the production performance of sows.

The development of a whole-cell biosensor enabled the identification of agmatine-producing Hafnia spp. in cheese

Agmatine, the decarboxylation product of arginine, is the precursor of putrescine - a harmful biogenic amine (BA) - that can accumulate in dairy products via bacterial metabolism involving the agmatine deiminase (AGDI) pathway. This first requires agmatine be produced via the decarboxylation of arginine and it remains unknown which microorganisms are responsible for this prior decarboxylation step. In addition, agmatine, as other BA, plays different physiological roles including those of co-transmitter and neuromodulator. Preclinical and clinical studies have shown agmatine to have a neuroprotective effect, rendering it of therapeutic interest being agmatine-producing bacteria proposed as psychobiotics. The identification of BA-producing microorganisms is based on the rise in pH due to the consumption of H+ during such decarboxylation reactions. However, in the detection of agmatine-producing microorganisms in cheese, this would lead to false positives since many bacteria possess arginine deiminase activity; this produces ornithine and ammonium from arginine, which also increases the pH. To overcome this problem, a whole-cell biosensor based on a previously developed agmatine-inducible transcription system was designed, and a protocol optimized for the successful identification of agmatine-producing microorganisms in cheese. The application of this protocol in cheese samples allowed for the isolation of agmatine-producing microorganisms identified as Hafnia spp. and unravels, for first time, the capacity of Hafnia paralvei to produce agmatine. This finding evidence the potential role of Hafnia spp. in putrescine accumulation in dairy products.

"Enhancing polyamine enrichment from wheat germs: A study utilizing response surface methodology and liquid chromatography-mass spectrometry"

Wheat germ is one of the richest natural sources of polyamines, especially spermidine. Cell proliferation property of polyamines has given them inductive effects in the reduction of a variety of chronic diseases and fertility enhancement. Preparing a polyamine-rich extract powder from wheat germ for use in supplements is the aim of the present study. For the first time, the effects of three independent variables of clean-up replicate (A), extraction time (B), and solid-to-liquid ratio (C) on the response of total spermidine content (Y) were investigated using a central composite design optimizing polyamine enrichment. The optimal extraction conditions were 7 h, 3 clean-up replicates, and 1:4 solid to liquid ratio. This is the first production report of spermidine-enriched powder for encapsulation purposes. To obtain an acceptable rheological property, the polyamine-enriched extract was spray dried together with a selected group of excipients, among which glucose was evidenced as the best choice based on encapsulation properties.

Impact of gut microbiota on cardiac aging

Recent research has suggested imbalances in gut microbiota composition as contributors to cardiac aging. An individual's physical condition, along with lifestyle-associated factors, including diet and medication, are significant determinants of gut microbiota composition. This review discusses evidence of bidirectional associations between aging and gut microbiota, identifying gut microbiota-derived metabolites as potential regulators of cardiac aging. It summarizes the effects of gut microbiota on cardiac aging diseases, including cardiac hypertrophy and fibrosis, heart failure, and atrial fibrillation. Furthermore, this review discusses the potential anti-aging effects of modifying gut microbiota composition through dietary and pharmacological interventions. Lastly, it underscores critical knowledge gaps and outlines future research directions. Given the current limited understanding of the direct relationship between gut microbiota and cardiac aging, there is an urgent need for preclinical and clinical investigations into the mechanistic interactions between gut microbiota and cardiac aging. Such endeavors hold promise for shedding light on the pathophysiology of cardiac aging and uncovering new therapeutic targets for cardiac aging diseases.

Targeting Ubiquitin-Proteasome System (UPS) in Treating Osteoarthritis

Despite osteoarthritis (OA) being recognised for over a century as a debilitating disease that affects millions, there are huge gaps in our understanding of the underlying pathophysiology that drives this disease. Present day studies that focussed on ubiquitination (Ub) and ubiquitylation-like (Ubl) modification related mechanisms have brought light into the possibility of attenuating OA development by targeting these specific proteins in chondrocytes. In the present review, we discuss recent advances in studies involving Ub ligases and deubiquitinating enzymes (DUBs) which are of importance in the development of OA, and may offer potential therapeutic strategies for OA. Such targets may involve attenuating proteases such as MMP1, 8, 13, 4 and several ADAMTS that are well known for their role in cartilage breakdown. Ligases such as E2 and E3 that are involved in extracellular matrix (ECM) degradation in OA and of their pathogenesis would be discussed. In addition to catabolic and degenerative downstream effects of Ub and DUBs in OA, inflammatory mechanisms most notably involving NF-κB signalling pathways regulated through Ub and using various targeting molecules would also be highlighted. Challenges, gaps and insights from clinical trials will provide valuable guidance for future investigations on targeting UPS as a therapeutic option for OA.

Spermidine alleviates thymopoiesis defects and aging of the peripheral T-cell population in mice after radiation exposure

The T cell aging process can be modified by genotoxic factors, including ionizing radiation, and metabolic controls, such as caloric restriction; the former accelerates and the latter retards the process. However, the mechanisms by which these systemic factors interact to cause T cell aging remain unclear. This study investigated the naïve T-cell pool, thymic cellularity, and transcriptome in mice irradiated with 3.8 Gy at 5 weeks of age and treated 13 months later with 30 mM spermidine (SPD), a metabolism regulator. The number of conventional naïve CD4 and CD8 T cells in the peripheral blood decreased 14 months after irradiation whereas the number of virtual memory naïve T cells, which increased with age, further increased by irradiation. However, these radiation-related changes were not significant in similarly irradiated mice that were subsequently treated with SPD. The numbers of total, double-positive, and single-positive thymocytes were decreased by irradiation, whereas none were decreased in the irradiated mice treated with SPD. RNA sequencing of thymus cells revealed 803 upregulated genes in irradiated mice compared with those in non-irradiated control mice, with these genes enriched in leukocyte activation and inflammatory cytokine production. However, only 22 genes were upregulated in irradiated and SPD-treated mice, suggesting a reversal of many radiation-induced gene expression changes. These findings suggest that SPD may alleviate radiation-induced acceleration of T-cell aging, particularly by mitigating reduced thymopoiesis and inflammation. Further research is warranted to explore the rejuvenating potential of SPD and its mechanisms of action in accelerated T-cell aging.

The putative polyamine transporter Shp2 facilitates phosphate export in an Xpr1-independent manner and contributes to high phosphate tolerance

Phosphate (Pi) homeostasis at the cellular level is crucial, requiring coordinated Pi uptake, storage, and export. However, the regulatory mechanisms, particularly those governing Pi export, remain elusive, despite their relevance to human diseases like primary familial brain calcification. While Xpr1, conserved across eukaryotes, is the only known Pi exporter, the existence of additional Pi exporting factors is evident; however, these factors have been poorly characterized. Using the fission yeast Schizosaccharomyces pombe as a model, we have aimed to better understand cellular Pi homeostasis mechanisms. Previously, we showed three Pi regulators with SPX domains to be critical: Pqr1 (Pi uptake restrictor), Xpr1/Spx2, and the VTC complex (polyphosphate synthase). SPX domains bind to inositol pyrophosphate, modulating Pi regulator functions. The double mutant Δpqr1Δxpr1 hyper-accumulates Pi and undergoes cell death under high Pi conditions, indicating the necessity of both Pi uptake restriction and export. Notably, Δpqr1Δxpr1 exhibits residual Pi export activity independent of Xpr1, suggesting the presence of unidentified Pi exporters. To uncover these cryptic Pi exporters and regulators of Pi homeostasis, we conducted suppressor screening for high Pi hypersensitivity in Δpqr1Δxpr1. Among the eight suppressors identified, Shp2, a plasma-membrane protein, showed Pi export-facilitating activity in an Xpr1-independent manner, supporting cell proliferation at high Pi. The present results provide the first evidence for Pi export facilitator other than the established Xpr1, unprecedented in eukaryotes. As Shp2 is orthologous to the budding yeast Tpo1, a spermidine/polyamine transporter, a potential link between Pi homeostasis and polyamine metabolism can be speculated.

Gut microbiome and bone health: update on mechanisms, clinical correlations, and possible treatment strategies

The intestinal microbiome is increasingly regarded as a relevant modulator of the pathophysiology of several age-related conditions, including frailty, sarcopenia, and cognitive decline. Aging is in fact associated with alteration of the equilibrium between symbiotic bacteria and opportunistic pathogens, leading to dysbiosis. The microbiome is able to regulate intestinal permeability and systemic inflammation, has a central role in intestinal amino acid metabolism, and produces a large number of metabolites and byproducts, with either beneficial or detrimental consequences for the host physiology. Recent evidence, from both preclinical animal models and clinical studies, suggests that these microbiome-centered pathways could contribute to bone homeostasis, regulating the balance between osteoblast and osteoclast function. In this systematic review, we provide an overview of the mechanisms involved in the gut-bone axis, with a particular focus on microbiome function and microbiome-derived mediators including short-chain fatty acids. We also review the current evidence linking gut microbiota dysbiosis with osteopenia and osteoporosis, and the results of the intervention studies on pre-, pro-, or post-biotics targeting bone mineral density loss in both animal models and human beings, indicating knowledge gaps and highlighting possible avenues for future research.

Quantitative Endogenous Polyamine Analysis via Capillary Electrophoresis/Mass Spectrometry: Characterization and Practical Considerations

Commonly used analytical techniques for polyamine analysis, including derivatization and mixed-mode liquid chromatography (LC), have inherent disadvantages. Capillary electrophoresis (CE) is uniquely suited to analyze small, highly charged molecules because analytes are separated on the basis of their electrophoretic mobility, not polarity or association with a stationary phase. Microfluidic CE-mass spectrometry (mCE-MS) is a relatively recent addition to commercially available CE offerings that streamlines traditional CE-MS interfacing and has the potential to improve upon classic CE challenges to robustness and reproducibility. MS instrument choice and scanning parameters are strongly influenced by a need for high acquisition rate to adequately sample CE peaks. Alternatively, isotachophoresis on loading can be intentionally avoided to produce sufficiently wide peaks. The mCE platform utilized here performed very well in many metrics; a limit of detection (LOD) as low as 0.25 ng/mL was achieved for spermidine, and endogenous spermidine was easily detected in blood with this method. Both of these are challenging tasks for any separation technique and demonstrate a strong use case for the platform. During experimentation, various idiosyncrasies in the commercial CE-MS interface resulted in extensive chip-to-chip variability in both peak shape and LOD, complicating the application to robust absolute quantitation. Practical guidance for similar analyses is provided.

Coupling of mitochondrial state with active zone plasticity in early brain aging

Neurodegenerative diseases typically emerge after an extended prodromal period, underscoring the critical importance of initiating interventions during the early stages of brain aging to enhance later resilience. Changes in presynaptic active zone proteins ("PreScale") are considered a dynamic, resilience-enhancing form of plasticity in the process of early, still reversible aging of the Drosophila brain. Aging, however, triggers significant changes not only of synapses but also mitochondria. While the two organelles are spaced in close proximity, likely reflecting a direct functional coupling in regard to ATP and Ca2+ homeostasis, the exact modes of coupling in the aging process remain to understood. We here show that genetic manipulations of mitochondrial functional status, which alters brain oxidative phosphorylation, ATP levels, or the production of reactive oxygen species (ROS), can bidirectionally regulate PreScale during early Drosophila brain aging. Conversely, genetic mimicry of PreScale resulted in decreased oxidative phosphorylation and ATP production, potentially due to reduced mitochondrial calcium (Ca2+) import. Our findings indicate the existence of a positive feedback loop where mitochondrial functional state and PreScale are reciprocally coupled to optimize protection during the early stages of brain aging.

The longevity factor spermidine is part of a highly heritable complex erythrocyte phenotype associated with longevity

Extreme longevity in humans is known to be a heritable trait. In a well-established twin erythrocyte metabolomics and proteomics database, we identified the longevity factor spermidine and a cluster of correlated molecules with high heritability estimates. Erythrocyte spermidine is 82% heritable and significantly correlated with 59 metabolites and 22 proteins. Thirty-eight metabolites and 19 proteins were >20% heritable, with a mean heritability of 61% for metabolites and 49% for proteins. Correlated metabolites are concentrated in energy metabolism, redox homeostasis, and autophagy pathways. Erythrocyte mean cell volume (MCV), an established heritable trait, was consistently negatively correlated with the top 25 biomolecules most strongly correlated with spermidine, indicating that smaller MCVs are associated with higher concentrations of spermidine and correlated molecules. Previous studies have linked larger MCVs with poorer memory, cognition, and all-cause mortality. Analysis of 432,682 unique patient records showed a linear increase in MCV with age but a significant deviation toward smaller than expected MCVs above age 86, suggesting that smaller MCVs are associated with extreme longevity. Consistent with previous reports, a subset of 78,158 unique patient records showed a significant skewing toward larger MCV values in a deceased cohort compared to an age-matched living cohort. Our study supports the existence of a complex, heritable phenotype in erythrocytes associated with health and longevity.

Absorption, anti-inflammatory, antioxidant, and cardioprotective impacts of a novel fasting mimetic containing spermidine, nicotinamide, palmitoylethanolamide, and oleoylethanolamide: A pilot dose-escalation study in healthy young adult men

This pilot dose-escalation study evaluated the absorption and metabolism of a novel fasting mimetic formulation containing spermidine, nicotinamide, palmitoylethanolamide (PEA), and oleoylethanolamide (OEA) taken as oral supplements in young adults. Five healthy men consumed a standardized breakfast, followed by control (wheat flour) or low, medium, or high doses of supplements containing spermidine, nicotinamide, PEA, and OEA 2 hours later. Blood was drawn at 0, 1, 2, and 4 hours after the supplement (2, 3, 4, and 6 hours postprandial). Plasma concentrations of spermidine, 1-methylnicotinamide, PEA and OEA were quantified by liquid chromatography-mass spectrometry. The secretion of tumor necrosis factor alpha and production of reactive oxygen species by stimulated macrophages incubated with plasma, and cholesterol efflux capacity of plasma were analyzed. Plasma 1-methylnicotinamide, PEA, and OEA concentrations increased after supplement intake (P < .05). Spermidine concentrations decreased in the control arm (P < .05) but not the supplement arms. Net incremental area under the curve for tumor necrosis factor alpha and reactive oxygen species in stimulated macrophages decreased when incubated with plasma following supplement intake (P < .05). Intake of the combined supplements showed they were bioavailable and increased in plasma in a dose-dependent manner and provide preliminary data showing enhanced plasma anti-inflammatory and antioxidant functions. This trial was registered at clinicaltrials.gov (NCT05017428).

Mechanism and clinical implication of gut dysbiosis in degenerative abdominal aortic aneurysm: A systematic review

The gut microbiome is the entirety of microorganisms and their genomes residing in the gut, characterised by diversity, stability, and resilience. Disrupted gut microbiome has been implicated in multiple disease entities. The aim of this paper is to summarise the rapidly evolving contemporary evidence of gut dysbiosis on the development and progression of abdominal aortic aneurysm (AAA), discuss possible mechanisms, and explore potential microbiota-targeted interventions and prognostic markers for AAA. A systematic literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, using PubMed, ScienceDirect, Web of Science, Ovid, Embase. Search terms of "microbiome" OR "dysbiosis" OR "microorganism"; AND "aneurysm" OR "dilatation" OR "aorta" were used. Study endpoints included effects of microbiota on AAA formation, effects of specific type of bacteria and its metabolite on AAA formation, and pre- or post-treatment by novel small-molecules/inhibitors. From May to August 2023, a total of twelve animal studies and eight human studies were included. Akkermansia muciniphila, Lactobacillus acidophilus and species from the Bacteroidetes phylum were associated with lower AAA incidence in both animal and human studies, while Proteobacteria phylum, Campylobacter, Fusobacterium and Faecalibacterium prausnitzii were found to be in abundance in the AAA group and were associated with larger aneurysms. The diversity of gut microbiota was inversely correlated with AAA diameter. Three important mechanisms were identified: including trimethylamine N-oxide pathway, butyric acid pathway, and aberrant tryptophan metabolism. With our expanding knowledge of the downstream pathogenic mechanisms of gut dysbiosis, novel therapeutics such as short-chain fatty acids and spermidine, as well as prognostic biomarkers such as TMAO have yielded promising preclinical results. In conclusion, there is strong evidence corroborating the role of gut dysbiosis in the pathogenesis of AAA, wherein its therapeutic and prognostic potential deserves further exploration.

Metabolic characteristics of prostate cancer cells with high metastatic potential revealed by (S)-ethyl 1-(3-(4-chlorophenoxy)-2-hydroxypropyl)-3-(4-methoxyphenyl)-1H-pyrazole-5-carboxylate inhibition

A small molecule, (S)-ethyl 1-(3-(4-chlorophenoxy)-2-hydroxypropyl)-3-(4-methoxyphenyl)-1H-pyrazole-5-carboxylate (SEC), has been reported to be capable of suppressing metastasis of prostate cancer (PCa) cells. In this study, SEC was used to study the metabolic responses of PCa cell lines (LNCaP, PC3, and DU145) with different metastatic potential and the alterations of mTOR, p-mTOR, AMPK, and p-AMPK levels, when the PCa cells were inhibited. The ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS)-based analysis showed that SEC induced the decreases of intracellular metabolites including glutamic acid, glutamine, and histidine (LNCaP); creatinine, citric acid/isocitric acid, and aspartic acid (PC3); and spermidine, S-hydroxymethylglutathione, LPE (20:3), and palmitic amide (DU145), and the increases of intracellular LPC (18:0) (LNCaP); tyrosine, pyroglutamic acid/pyrroline hydroxycarboxylic acid (PC3); and tyrosine, phenylalanine, phenylacetylglycine, spermine, histidine, and choline (DU145). SEC also caused the decrease of extracellular N1-acetylspermidine (LNCaP), erythronic acid/threonic acid (PC3 and DU145), and nicotinic acid/picolinic acid (DU145), and the increase of extracellular 5'-methylthioadenosine (DU145). High metastatic PC3 and DU145 cells exhibited changes in aromatic amino acid metabolism including tyrosine metabolism, phenylalanine, tyrosine, and tryptophan metabolism, and phenylalanine metabolism (PC3 and DU145), TCA cycle (PC3), arginine and proline metabolism, and glycerophospholipid metabolism (DU145), different from the low metastatic LNCaP cells, which had changes in alanine, aspartate, and glutamate metabolism, and arginine biosynthesis. In addition, the levels of p-mTOR and p-AMPK were shown to be obviously downregulated and upregulated, respectively, in high metastatic PC3 and DU145 cells upon SEC inhibition, while this behavior was not detected in LNCaP cells.

Development of a novel centrosome-related risk signature to predict prognosis and treatment response in lung adenocarcinoma

BACKGROUND

Abnormalities of centrosomes, the major microtubular organizing centers of animal cells and regulators of cell cycle progression, usually accelerate tumor progression, but their prognostic value in lung adenocarcinoma (LUAD) remains insufficiently explored.

METHODS

We collected centrosome genes from the literature and identified LUAD-specific centrosome-related genes (CRGs) using the single-sample gene set enrichment analysis (ssGSEA) algorithm and weighted gene co-expression network analysis (WGCNA). Univariate Cox was performed to screen prognostic CRGs. Consistent clustering was performed to classify LUAD patients into two subgroups, and centrosome-related risk score signatures were constructed by Lasso and multivariate Cox regression to predict overall survival (OS). We further explored the correlation between CRS and patient prognosis, clinical manifestations, mutation status, tumor microenvironment, and response to different treatments.

RESULTS

We constructed centrosome-associated prognostic features and verified that CRS could effectively predict 1-, 3-, and 5-year survival in LUAD patients. In addition, patients in the high-risk group exhibited elevated tumor mutational loads and reduced levels of immune infiltration, particularly of T and B cells. Patients in the high-risk group were resistant to immunotherapy and sensitive to 5-fluoropyrimidine and gefitinib. The key gene spermine synthase (SRM) is highly expressed at the mRNA and protein levels in LUAD.

DISCUSSION

Our work develops a novel centrosome-related prognostic signature that accurately predicts OS in LUAD and can assist in clinical diagnosis and treatment.

Climbing the longevity pyramid: overview of evidence-driven healthcare prevention strategies for human longevity

Longevity medicine is an emerging and iterative healthcare discipline focusing on early detection, preventive measures, and personalized approaches that aim to extend healthy lifespan and promote healthy aging. This comprehensive review introduces the innovative concept of the "Longevity Pyramid." This conceptual framework delineates progressive intervention levels, providing a structured approach to understanding the diverse strategies available in longevity medicine. At the base of the Longevity Pyramid lies the level of prevention, emphasizing early detection strategies and advanced diagnostics or timely identification of potential health issues. Moving upwards, the next step involves lifestyle modifications, health-promoting behaviors, and proactive measures to delay the onset of age-related conditions. The Longevity Pyramid further explores the vast range of personalized interventions, highlighting the importance of tailoring medical approaches based on genetic predispositions, lifestyle factors, and unique health profiles, thereby optimizing interventions for maximal efficacy. These interventions aim to extend lifespan and reduce the impact and severity of age-related conditions, ensuring that additional years are characterized by vitality and wellbeing. By outlining these progressive levels of intervention, this review offers valuable insights into the evolving field of longevity medicine. This structured framework guides researchers and practitioners toward a nuanced strategic approach to advancing the science and practice of healthy aging.

Serine metabolism in aging and age-related diseases

Non-essential amino acids are often overlooked in biomedical research; however, they are crucial components of organismal metabolism. One such metabolite that is integral to physiological function is serine. Serine acts as a pivotal link connecting glycolysis with one-carbon and lipid metabolism, as well as with pyruvate and glutathione syntheses. Interestingly, increasing evidence suggests that serine metabolism may impact the aging process, and supplementation with serine may confer benefits in safeguarding against aging and age-related disorders. This review synthesizes recent insights into the regulation of serine metabolism during aging and its potential to promote healthy lifespan and mitigate a spectrum of age-related diseases.

Asparagine prevents intestinal stem cell aging via the autophagy-lysosomal pathway

The age-associated decline in intestinal stem cell (ISC) function is a key factor in intestinal aging in organisms, resulting in impaired intestinal function and increased susceptibility to age-related diseases. Consequently, it is imperative to develop effective therapeutic strategies to prevent ISC aging and functional decline. In this study, we utilized an aging Drosophila model screening of amino acids and found that asparagine (Asn), a nonessential amino acid in vivo, exhibits its profound anti-aging properties on ISCs. Asn inhibits the hyperproliferation of aging ISCs in Drosophila, maintains intestinal homeostasis, and extends the lifespan of aging flies. Complementarily, Asn promotes the growth and branching of elderly murine intestinal organoids, indicating its anti-aging capacity to enhance ISC function. Mechanistic analyses have revealed that Asn exerts its effects via the activation of the autophagic signaling pathway. In summary, this study has preliminarily explored the potential supportive role of Asn in ameliorating intestinal aging, providing a foundation for further research into therapeutic interventions targeting age-related intestinal dysfunction.

Interpretation of the pathogenesis and therapeutic mechanisms of first-episode major depressive disorder based on multiple amino acid metabolic pathways: a metabolomics study

OBJECTIVES

Given the unclear etiology and treatment mechanisms of depression, we aim to explore the metabolic differences between patients with major depressive disorder (MDD) and the healthy population, as well as before and after treatment with escitalopram (ESC).

METHODS

Recruit first-episode drug-naïve MDD (DN-MDD) patients and healthy controls (HCs). Clinical data and serum samples from all subjects were collected at baseline and patients' samples were collected again after ESC monotherapy for four weeks. Perform non-targeted metabolomic analysis and apply MetaboAnalyst 5.0 to identify differential metabolites and execute KEGG pathway enrichment.

RESULTS

Through metabolomic analysis of serum samples, 904 differential metabolites were identified in the DN-MDD group compared to the HCs, and 455 metabolites in treated patients compared to DN-MDD patients. In the pathway analysis, DN-MDD state regulated functions of histidine, beta-alanine, aspartate, and tryptophan metabolism, while ESC treatment produced an influence on the biological process of aspartate and sphingolipid.

CONCLUSION

We respectively depicted metabolism-related biomolecular changes in the serum of patients suffering from MDD and undergoing ESC treatment. Multiple amino acid metabolism pathways were adjusted in MDD patients, and levels of aspartate, arginine and sphingolipids were regulated after ESC monotherapy. These biomolecular changes may bring new insights into the biology and treatment of MDD from the perspective of the serum metabolites.

Probiotics and their metabolite spermidine enhance IFN-γ+CD4+ T cell immunity to inhibit hepatitis B virus

The therapeutic potential of commensal microbes and their metabolites is promising in the functional cure of chronic hepatitis B virus (HBV) infection, which is defined as hepatitis B surface antigen (HBsAg) loss. Here, using both specific-pathogen-free and germ-free mice, we report that probiotics significantly promote the decline of HBsAg and inhibit HBV replication by enhancing intestinal homeostasis and provoking intrahepatic interferon (IFN)-γ+CD4+ T cell immune response. Depletion of CD4+ T cells or blockage of IFN-γ abolishes probiotics-mediated HBV inhibition. Specifically, probiotics-derived spermidine accumulates in the gut and transports to the liver, where it exhibits a similar anti-HBV effect. Mechanistically, spermidine enhances IFN-γ+CD4+ T cell immunity by autophagy. Strikingly, administration of probiotics in HBV patients reveals a preliminary trend to accelerate the decline of serum HBsAg. In conclusion, probiotics and their derived spermidine promote HBV clearance via autophagy-enhanced IFN-γ+CD4+ T cell immunity, highlighting the therapeutic potential of probiotics and spermidine for the functional cure of HBV patients.

Genetically encoded fluorescent reporter for polyamines

Polyamines are abundant and evolutionarily conserved metabolites that are essential for life. Dietary polyamine supplementation extends life-span and health-span. Dysregulation of polyamine homeostasis is linked to Parkinson's disease and cancer, driving interest in therapeutically targeting this pathway. However, measuring cellular polyamine levels, which vary across cell types and states, remains challenging. We introduce a first-in-class genetically encoded polyamine reporter for real-time measurement of polyamine concentrations in single living cells. This reporter utilizes the polyamine-responsive ribosomal frameshift motif from the OAZ1 gene. We demonstrate broad applicability of this approach and reveal dynamic changes in polyamine levels in response to genetic and pharmacological perturbations. Using this reporter, we conducted a genome-wide CRISPR screen and uncovered an unexpected link between mitochondrial respiration and polyamine import, which are both risk factors for Parkinson's disease. By offering a new lens to examine polyamine biology, this reporter may advance our understanding of these ubiquitous metabolites and accelerate therapy development.

Unveiling the Longevity Potential of Natural Phytochemicals: A Comprehensive Review of Active Ingredients in Dietary Plants and Herbs

Ancient humans used dietary plants and herbs to treat disease and to pursue eternal life. Today, phytochemicals in dietary plants and herbs have been shown to be the active ingredients, some of which have antiaging and longevity-promoting effects. Here, we summarize 210 antiaging phytochemicals in dietary plants and herbs, systematically classify them into 8 groups. We found that all groups of phytochemicals can be categorized into six areas that regulate organism longevity: ROS levels, nutrient sensing network, mitochondria, autophagy, gut microbiota, and lipid metabolism. We review the role of these processes in aging and the molecular mechanism of the health benefits through phytochemical-mediated regulation. Among these, how phytochemicals promote longevity through the gut microbiota and lipid metabolism is rarely highlighted in the field. Our understanding of the mechanisms of phytochemicals based on the above six aspects may provide a theoretical basis for the further development of antiaging drugs and new insights into the promotion of human longevity.

Scientific landscape of oxidative stress in sarcopenia: from bibliometric analysis to hotspots review

Objective

Sarcopenia is a significant healthcare challenge in the aging population. Oxidative stress (OS) is acknowledged to play a pivotal role in the pathological progression of sarcopenia. Numerous studies have demonstrated that mitigating or eliminating OS can ameliorate the pathological manifestations associated with sarcopenia. However, current clinical antioxidant therapies often fall short of anticipated outcomes. This bibliometric analysis aims to delineate prevailing research trends, thematic emphases, focal points, and developmental trajectories within the domain of OS in sarcopenia, while also endeavoring to explore prospective anti-oxidative stress strategies for future clinical interventions.

Methods

Relevant publications were retrieved from the Web of Science (WOS) Core Collection database for the period 2000-2024. Citespace was employed for retrieving and analyzing trends and emerging topics.

Results

In the field of OS in sarcopenia, the number of publications has significantly increased from 2000 to 2024. The United States and China are the primary contributors to global publication output. The most productive research institution is INRAE. The most prolific author is Holly Van Remmen from the United States, while the most frequently cited author is Cruz-Jentoft AJ from Spain. Experimental Gerontology is the journal with the highest volume of published articles, whereas the Journal of Gerontology Series A: Biological Sciences and Medical Sciences holds the record for the highest number of citations. The research keywords in this field can be categorized into eight domains: "Physiology and anatomy", "Physiological mechanisms", "Pathology associations", "Experimental studies", "Nutrition and metabolism", "Sports and physical activities", "Age" and "Oxidation and antioxidation". Moreover, recent years have seen the emergence of "TNF-α," "insulin resistance", "mitochondrial autophagy", "signal pathways", and "mechanisms" as focal points in the realm of OS in sarcopenia, encompassing related fundamental research and clinical translation.

Conclusion

This bibliometric and visualization provides a comprehensive analysis of the global research landscape in the field of OS in sarcopenia, identifies priorities, summarizes the current research status and suggests possible future research priorities. In addition, in order to benefit more sarcopenia patients, strengthening cooperation and communication between institutions and research teams is the key to the future development of this field. Given the expectation that research on OS in sarcopenia will remain a prominent area of interest in the future, this article could serve as a valuable resource for scholars seeking to shape future studies through an understanding of influential scholarly contributions and key research findings.

Systematic review registration

https://www.crd.york.ac.uk, identifier CRD42024528628.

Spermidine Associated with Gut Microbiota Protects Against MRSA Bloodstream Infection by Promoting Macrophage M2 Polarization

Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen that causes various diseases. Extensive researches highlight the significant role of gut microbiota and its metabolites, particularly spermidine, in infectious diseases. However, the immunomodulatory mechanisms of spermidine in MRSA-induced bloodstream infection remain unclear. Here, we confirmed the protective effects of spermidine in bloodstream infection in mice. Spermidine reduced the bacterial load and expression of inflammatory factors by shifting the macrophage phenotype to an anti-inflammatory phenotype, ultimately prolonging the survival of the infected mice. The protective effect against MRSA infection may rely on the elevated expression of protein tyrosine phosphatase nonreceptor 2 (PTPN2). Collectively, these findings confirm the immunoprotective effects of spermidine via binding to PTPN2 in MRSA bloodstream infection, providing new ideas for the treatment of related infectious diseases.

Hyaluronic acid methacrylate/Pluronic F127 hydrogel enhanced with spermidine-modified mesoporous polydopamine nanoparticles for efficient synergistic periodontitis treatment

Bacterial infection, reactive oxygen species (ROS) accumulation, and persistent inflammation pose significant challenges in the treatment of periodontitis. However, the current single-modal strategy makes achieving the best treatment effect difficult. Herein, we developed a double-network hydrogel composed of Pluronic F127 (PF-127) and hyaluronic acid methacrylate (HAMA) loaded with spermidine-modified mesoporous polydopamine nanoparticles (M@S NPs). The PF-127/HAMA/M@S (PH/M@S) hydrogel was injectable and exhibited thermosensitivity and photocrosslinking capabilities, which enable it to adapt to the irregular shape of periodontal pockets. In vitro, the PH/M@S displayed multiple therapeutic effects, such as photothermal antibacterial activity, a high ROS scavenging capacity, and anti-inflammatory effects, which are beneficial for the multimodal treatment of periodontitis. The underlying anti-inflammatory mechanism of this hydrogel involves suppression of the extracellular regulated protein kinase 1/2 and nuclear factor kappa-B signalling pathways. Furthermore, in lipopolysaccharide-stimulated macrophage conditioned media, the PH/M@S effectively restored the osteogenic differentiation potential. In a rat model of periodontitis, the PH/M@S effectively reduced the bacterial load, relieved local inflammation and inhibited alveolar bone resorption. Collectively, these findings highlight the versatile functions of the PH/M@S, including photothermal antibacterial activity, ROS scavenging, and anti-inflammatory effects, indicating that this hydrogel is a promising multifunctional filling material for the treatment of periodontitis.

Multifunctional Copper-Phenolic Nanopills Achieve Comprehensive Polyamines Depletion to Provoke Enhanced Pyroptosis and Cuproptosis for Cancer Immunotherapy

The overexpression of polyamines in tumor cells contributes to the establishment of immunosuppressive microenvironment and facilitates tumor growth. Here, it have ingeniously designed multifunctional copper-piceatannol/HA nanopills (Cu-Pic/HA NPs) that effectively cause total intracellular polyamines depletion by inhibiting polyamines synthesis, depleting intracellular polyamines, and impairing polyamines uptake, resulting in enhanced pyroptosis and cuproptosis, thus activating a powerful immune response to achieve anti-tumor therapy. Mitochondrial dysfunction resulting from overall intracellular polyamines depletion not only leads to the surge of copper ions in mitochondria, thereby causing the aggregation of toxic proteins to induce cuproptosis, but also triggers the accumulation of reactive oxygen species (ROS) within mitochondria, which further upregulates the expression of zDHHC5 and zDHHC9 to promote the palmitoylation of gasdermin D (GSDMD) and GSDMD-N, ultimately inducing enhanced pyroptosis. Then the occurrence of enhanced pyroptosis and cuproptosis is conductive to remodel the immunosuppressive tumor microenvironment, thus activating anti-tumor immune responses and ultimately effectively inhibiting tumor growth and metastasis. This therapeutic strategy of enhanced pyroptosis and cuproptosis through comprehensive polyamines depletion provides a novel template for cancer immunotherapy.

Phytochemistry, pharmacological applications, and therapeutic effects of green synthesized nanomaterials using Cichorium species-a comprehensive review

Cichorium is a genus of potential medicinal herbs that finds widespread cultivation in regions spanning Asia and Europe. Belonging to the Asteraceae family, these plants are typically biennial or perennial in nature. Among the various explored varieties of chicory plants, the most commonly studied ones include Cichorium intybus, Cichorium endivia, and Cichorium pumilum. In Ayurveda, chicory has long been used as a remedy for many health problems. This versatile plant is renowned for its efficacy in managing conditions such as gallstones, gastroenteritis, sinus ailments, and the treatment of skin abrasions and wounds. Numerous bioactives, including polysaccharides, caffeic acid, flavonoids, coumarins, steroids, alkaloids, organic acids, triterpenoids, sesquiterpenoids, and essential oils, are present, according to a thorough phytochemical examination. The phytochemicals isolated from chicory have displayed significant therapeutic activities, including antidiabetic effects, hepatoprotective benefits, anti-obesity properties, and anti-cancer potential, as extensively documented by numerous researchers. The incorporation of these bioactive compounds into one's diet as part of a healthy lifestyle has demonstrated considerable advantages for human well-being. Green synthesis is a recent technology in which plant extracts or phytochemicals are used for synthesizing nanoparticles since plant extracts are generally less toxic and contain capping and reducing agents. This review summarizes current developments in green synthesis employing phytoconstituents from Cichorium species and extracts from various plant parts and their application to scientific problems. In order to preserve lifestyles and cure human diseases, the investigation emphasizes the therapeutic effects of the chemical components and nanoparticles obtained from the extract of Cichorium species.

Protective effects of spermidine levels against cardiovascular risk factors: An exploration of causality based on a bi-directional Mendelian randomization analysis

The study investigated the causal relationships between spermidine levels and CVD risk factors using a bi-directional MR approach. Employing genetic variants from extensive GWAS datasets as IVs, the study aimed to determine whether spermidine levels can influence CVD risk factors such as blood pressure, blood glucose, and lipid profiles, and vice versa. The findings suggest a protective role of elevated spermidine levels against hypertension, elevated blood glucose, and lipid profiles (LDL-C and HDL-C). Specifically, increased spermidine levels were significantly associated with lower risk of hypertension (IVW beta = -0.0013453913, p = 0.01597648) and suppression risk of elevated blood glucose (IVW beta = -0.08061330, p = 0.02450205). Additionally, there was a notable association with lipid modulation, showing a decrease in LDL-C (IVW beta = -0.01849161, p = 0.01086728) and an increase in HDL-C (IVW beta = 0.0044608332, P = 0.01760051). Conversely, the influence of CVD risk factors on spermidine levels was minimal, with the exception that elevated blood glucose levels resulted in reduced spermidine levels. (IVW beta = -0.06714391, P = 0.01096123). These results underline the potential of spermidine as a modifiable dietary target for the prevention and management of cardiovascular diseases. Further investigations are warranted to explore the underlying biological mechanisms and the applicability of these findings in broader and diverse populations.

Circulating Metabolic Markers Identify Patients at Risk for Tumor Recurrence: A Prospective Cohort Study in Colorectal Cancer Surgery

OBJECTIVE

To investigate the spermidine pathway capability to predict patients at risk for tumor recurrence following colorectal cancer (CRC) surgery.

BACKGROUND

Recurrence rates after CRC surgery remain at about 20% despite an optimal technique and adjuvant therapy when necessary. Identification of risk biomarkers of recurrence is an unmet need. The spermidine pathway is indispensable for cell proliferation and differentiation, and is suggested to accelerate tumor spread.

METHODS

This was a prospective cohort study of patients undergoing CRC surgery from 2015 to 2018. Plasma samples were collected before surgery and on postoperative day 4, and the spermidine pathway was assessed through mass spectrometry. Oncological outcomes were registered.

RESULTS

A total of 146 patients were included and 24 (16.4%) developed tumor recurrence. Higher levels of preoperative spermidine pathway components (spermidine, spermine, spermidine synthase enzyme, and spermine/arginine balance) were positively associated with recurrence. Surgery promoted a decrease in these pathway elements. The greater the decline was, the lower the risk of recurrence. Preoperative spermidine over the cut-off of 0.198 µM displayed a 4.69-fold higher risk of recurrence. The spermine synthase enzyme behaved in the opposite direction.

CONCLUSIONS

The spermidine pathway is associated with tumor recurrence following CRC surgery and, after confirmation in larger cohorts, could be translated as a risk biomarker of recurrence into clinical practice.

Spermidine protects cellular redox status and ionic homeostasis in D-galactose induced senescence and natural aging rat models

Impaired redox homeostasis is an important hallmark of aging. Among various anti-aging interventions, caloric restriction mimetics (CRMs) are the most effective in promoting health and longevity. The potential role of spermidine (SPD) as a CRM in modulating oxidative stress and redox homeostasis during aging remains unclear. This study aimed to investigate the protective effect of SPD in D-galactose (D-gal) accelerated induced senescence model and naturally aged rats. Young male rats (4 months), D-gal induced (500 mg/kg b. w., subcutaneously) aging model and naturally aged (22 months) rats were supplemented with SPD (10 mg/kg b. w., orally) for 6 weeks. The results showed that SPD supplementation suppresses the age induced increase in reactive oxygen species, lipid peroxidation and protein oxidation. Additionally, it increases the level of antioxidants, plasma membrane redox system in erythrocytes and membrane. These results also indicate that membrane transporter activity is correlated with the susceptibility of the erythrocyte towards oxidative damage. We therefore present evidence that SPD improves redox status and membrane impairments in erythrocytes in experimental and naturally aging rat models, however, more research is required to recommend a potential therapeutic role for SPD as an anti-aging intervention strategy.

The roles of arginases and arginine in immunity

Arginase activity and arginine metabolism in immune cells have important consequences for health and disease. Their dysregulation is commonly observed in cancer, autoimmune disorders and infectious diseases. Following the initial description of a role for arginase in the dysfunction of T cells mounting an antitumour response, numerous studies have broadened our understanding of the regulation and expression of arginases and their integration with other metabolic pathways. Here, we highlight the differences in arginase compartmentalization and storage between humans and rodents that should be taken into consideration when assessing the effects of arginase activity. We detail the roles of arginases, arginine and its metabolites in immune cells and their effects in the context of cancer, autoimmunity and infectious disease. Finally, we explore potential therapeutic strategies targeting arginases and arginine.

Supplementation of spermidine enhances the quality of postovulatory aged porcine oocytes

BACKGROUND

Spermidine (SPD) is an intermediate compound in the polyamine metabolism which takes critical part in a variety of cellular processes. In particular, it has been reported to exert anti-aging effects, suppress the age-related diseases, and extend lifespan across species. However, whether it has the favorable influence on the quality of postovulatory aged oocytes remains elusive.

METHODS

Immunostaining and fluorescence intensity measurement were used to evaluate the effects of postovulatory aging and SPD supplementation on the oocyte fragmentation, spindle/chromosome structure, actin polymerization, dynamics of cortical granules (CGs) and ovastacin, mitochondrial distribution and function, as well as autophagy levels. In addition, in vitro sperm binding assay and in vitro fertilization (IVF) experiment were applied to assess the impacts of postovulatory aging and SPD supplementation on the sperm binding ability and fertilization capacity of oocytes.

RESULTS

Here, we showed that supplementation of SPD during postovulatory aging could relieve the deterioration of porcine oocytes. Specifically, we found that postovulatory aging impaired the oocyte quality by damaging the morphological integrity of oocytes, maintenance of spindle/chromosome structure, and dynamics of actin cytoskeleton. Postovulatory aging also weakened the sperm binding ability and fertilization capacity of oocytes by compromising the distribution pattern of CGs and their content ovastacin. Notably, supplementation of SPD attenuated these defects in postovulatory aged porcine oocytes via strengthening mitochondrial function, eliminating excessive reactive oxygen species (ROS), inhibiting apoptosis, and enhancing autophagy levels.

CONCLUSION

Altogether, our findings demonstrate that SPD supplementation is a feasible approach to ameliorate the quality of postovulatory aged oocytes, which can be potentially applied to the human assisted reproductive technology (ART) and in vitro production of animal embryos.

Difference in gut microbial dysbiotic patterns between body-first and brain-first Parkinson's disease

BACKGROUND

This study aims to identify distinct microbial and functional biomarkers characteristic of body-first or brain-first subtypes of Parkinson's disease (PD). This could illuminate the unique pathogenic mechanisms within these subtypes.

METHODS

In this cross-sectional study, we classified 36 well-characterized PD patients into body-first, brain-first, or undetermined subtypes based on the presence of premotor REM sleep behavior disorder (RBD) and cardiac meta-iodobenzylguanidine (MIBG) uptake. We then conducted an in-depth shotgun metagenomic analysis of the gut microbiome for each subtype and compared the results with those from age- and sex-matched healthy controls.

RESULTS

Significant differences were found in the gut microbiome of body-first PD patients (n = 15) compared to both brain-first PD patients (n = 9) and healthy controls. The gut microbiome in body-first PD showed a distinct profile, characterized by an increased presence of Escherichia coli and Akkermansia muciniphila, and a decreased abundance of short-chain fatty acid-producing commensal bacteria. These shifts were accompanied by a higher abundance of microbial genes associated with curli protein biosynthesis and a lower abundance of genes involved in putrescine and spermidine biosynthesis. Furthermore, the combined use of premotor RBD and MIBG criteria was more strongly correlated with these microbiome differences than the use of each criterion independently.

CONCLUSIONS

Our findings highlight the significant role of dysbiotic and pathogenic gut microbial alterations in body-first PD, supporting the body-first versus brain-first hypothesis. These insights not only reinforce the gut microbiome's potential as a therapeutic target in PD but also suggest the possibility of developing subtype-specific treatment strategies.

Lighting up arginine metabolism reveals its functional diversity in physiology and pathology

Arginine is one of the most metabolically versatile amino acids and plays pivotal roles in diverse biological and pathological processes; however, sensitive tracking of arginine dynamics in situ remains technically challenging. Here, we engineer high-performance fluorescent biosensors, denoted sensitive to arginine (STAR), to illuminate arginine metabolism in cells, mice, and clinical samples. Utilizing STAR, we demonstrate the effects of different amino acids in regulating intra- and extracellular arginine levels. STAR enabled live-cell monitoring of arginine fluctuations during macrophage activation, phagocytosis, efferocytosis, and senescence and revealed cellular senescence depending on arginine availability. Moreover, a simple and fast assay based on STAR revealed that serum arginine levels tended to increase with age, and the elevated serum arginine level is a potential indicator for discriminating the progression and severity of vitiligo. Collectively, our study provides important insights into the metabolic and functional roles of arginine, as well as its potential in diagnostic and therapeutic applications.

Exploration of Nutraceutical Potentials of Isorhapontigenin, Oxyresveratrol and Pterostilbene: A Metabolomic Approach

Resveratrol (trans-3,5,4'-trihydroxystilbene, RES) is one of the most well-known natural products with numerous health benefits. To explore the nutraceutical potentials of some dietary RES derivatives including isorhapontigenin (trans-3,5,4'-trihydroxy-3'-methoxystilbene, ISO), oxyresveratrol (trans-3,5,2',4'-tetrahydroxystilbene, OXY) and pterostilbene (trans-3,5-dimethoxy-4'-hydroxystilbene, PTS), their impacts on metabolism and health were assessed in Sprague Dawley rats after a two-week daily oral administration at the dose of 100 µmol/kg/day. Non-targeted metabolomic analyses were carried out with the liver, heart, brain and plasma samples using gas chromatography-tandem mass spectrometry (GC-MS/MS). Notable in vivo health benefits were observed, as the rats received ISO, PTS or RES showed less body weight gain; the rats received OXY or RES displayed healthier fasting blood glucose levels; while all of the tested stilbenes exhibited cholesterol-lowering effects. Additionally, many important metabolic pathways such as glycolysis, pentose phosphate pathway, tricarboxylic acid cycle and fatty acid oxidation were found to be modulated by the tested stilbenes. Besides the reaffirmation of the well-known beneficial effects of RES in diabetes, obesity, cardiovascular disease and Alzheimer's disease, the metabolomic analyses also suggest the anti-diabetic, cardio-, hepato- and neuro-protective activities of ISO; the anti-diabetic, cardio-, hepato- and neuro-protective effects of OXY; and the anti-aging, anti-inflammatory, cardio-, hepato- and neuro-protective potential of PTS. Interestingly, although these stilbenes share a similar structure, their biological activities appear to be distinct. In conclusion, similarly to RES, ISO, OXY and PTS have emerged as promising candidates for further nutraceutical development.

Intestinal Lactobacillus murinus-derived small RNAs target porcine polyamine metabolism

Gut microbiota plays a vital role in host metabolism; however, the influence of gut microbes on polyamine metabolism is unknown. Here, we found germ-free models possess elevated polyamine levels in the colon. Mechanistically, intestinal Lactobacillus murinus-derived small RNAs in extracellular vesicles down-regulate host polyamine metabolism by targeting the expression of enzymes in polyamine metabolism. In addition, Lactobacillus murinus delays recovery of dextran sodium sulfate-induced colitis by reducing polyamine levels in mice. Notably, a decline in the abundance of small RNAs was observed in the colon of mice with colorectal cancer (CRC) and human CRC specimens, accompanied by elevated polyamine levels. Collectively, our study identifies a specific underlying mechanism used by intestinal microbiota to modulate host polyamine metabolism, which provides potential intervention for the treatment of polyamine-associated diseases.

EMF treatment delays mesenchymal stem cells senescence during long-term in vitro expansion by modulating autophagy

Introduction

Bone marrow mesenchymal stem cells (BMSCs) are widely used in tissue engineering and regenerative medicine as seed cells. Due to low amount in bone marrow, BMSCs must be expanded and cultured in vitro before application. However, the senescence of stem cell caused by long-term in vitro culture greatly limits its efficacy of transplantation.

Methods

In this study, we propose an approach based on electromagnetic fields (EMF) treatment to rejuvenate aged BMSCs due to long-term in vitro culture. Aged BMSCs were treated with sinusoidal EMF (50 Hz, 0.4 mT), and stem cell senescence, cell proliferation, cell differentiation, cell stemness and autophagy level were detected. Additionally, aged BMSCs-laden hydrogels were transplanted into the rat critical-sized calvarial defect with or without EMF treatment. The bone formation was evaluated 8 weeks after surgery.

Results

Our results indicated that the BMSCs age significantly after long-term in vitro passaging. The self-renew, multiple differentiation capacity, senescence phenotypes and stemness of aged BMSCs are partly reversed by EMF treatment with a frequency of 50 Hz and strength of 0.4 mT. Moreover, declined autophagy level is observed in BMSCs during long-term in vitro passaging and BMSCs senescence is closely associated with autophagy regulation. Additionally, the mechanistic investigation reveals that EMF treatment rejuvenate senescent BMSCs by enhancing autophagy. Furthermore, EMF treatment significantly promote the therapeutic effect of long-term passaged BMSCs on bone formation in vivo.

Conclusion

Overall, our study identifies a practical approach for the rejuvenation of old BMSCs and may provide a promising candidate in tissue engineering and stem cell therapy.

Spermidine attenuates chondrocyte inflammation and cellular pyroptosis through the AhR/NF-κB axis and the NLRP3/caspase-1/GSDMD pathway

Introduction

Osteoarthritis (OA) is a prevalent chronic degenerative disease, marked by a complex interplay of mechanical stress, inflammation, and metabolic imbalances. Recent studies have highlighted the potential of spermidine (SPD), a naturally occurring polyamine known for its anti-inflammatory and antioxidant properties, as a promising therapeutic agent for OA. This study delves into the therapeutic efficacy and mechanistic pathways of SPD in mitigating OA symptoms.

Methods

Forty Sprague-Dawley rats were randomly assigned to four groups, including the CG (sham operation), model (anterior cruciate ligament transection [ACLT], and treatment (ACLT + two different doses of SPD) groups. In vivo, correlations between OA severity and different interventions were assessed by ELISA, X-rays, CT imaging, histological staining, and immunohistochemistry. In vitro, IL-1β was used to trigger chondrocyte inflammation, and SPD's cytotoxicity was assessed in primary rat chondrocytes. Next, inflammatory markers, extracellular matrix (ECM) proteins, and pathway marker proteins were detected in chondrocytes administered IL-1β alone, SPD, or aryl hydrocarbon receptor (AhR) silencing, by qRT-PCR, Griess reaction, ELISA, Western blot, and immunofluorescence. Morphological alterations and pyroptosis in chondrocytes were examined by transmission electron microscopy (TEM) and flow cytometry.

Results

Our research reveals that SPD exerts significant anti-inflammatory and antipyroptotic effects on IL-1β-treated chondrocytes and in anterior cruciate ligament transection (ACLT) rat models of OA, primarily through interaction with the Aryl hydrocarbon receptor (AhR). Specifically, SPD's binding to AhR plays a crucial role in modulating the inflammatory response and cellular pyroptosis by inhibiting both the AhR/NF-κB and NLRP3/caspase-1/GSDMD signaling pathways. Furthermore, the knockdown of AhR was found to negate the beneficial effects of SPD, underscoring the centrality of the AhR pathway in SPD's action mechanism. Additionally, SPD was observed to promote the preservation of cartilage integrity and suppress ECM degradation, further supporting its potential as an effective intervention for OA.

Discussion

Collectively, our findings propose SPD as a novel therapeutic approach for OA treatment, targeting the AhR pathway to counteract the disease's progression and highlighting the need for further clinical evaluation to fully establish its therapeutic utility.

Polyamine Anabolism Promotes Chemotherapy-Induced Breast Cancer Stem Cell Enrichment

Breast cancer patients may initially benefit from cytotoxic chemotherapy but experience treatment resistance and relapse. Chemoresistant breast cancer stem cells (BCSCs) play a pivotal role in cancer recurrence and metastasis, however, identification and eradication of BCSC population in patients are challenging. Here, an mRNA-based BCSC signature is developed using machine learning strategy to evaluate cancer stemness in primary breast cancer patient samples. Using the BCSC signature, a critical role of polyamine anabolism in the regulation of chemotherapy-induced BCSC enrichment, is elucidated. Mechanistically, two key polyamine anabolic enzymes, ODC1 and SRM, are directly activated by transcription factor HIF-1 in response to chemotherapy. Genetic inhibition of HIF-1-controlled polyamine anabolism blocks chemotherapy-induced BCSC enrichment in vitro and in xenograft mice. A novel specific HIF-1 inhibitor britannin is identified through a natural compound library screening, and demonstrate that coadministration of britannin efficiently inhibits chemotherapy-induced HIF-1 transcriptional activity, ODC1 and SRM expression, polyamine levels, and BCSC enrichment in vitro and in xenograft and autochthonous mouse models. The findings demonstrate the key role of polyamine anabolism in BCSC regulation and provide a new strategy for breast cancer treatment.

Effect of spermidine intake on skeletal muscle regeneration after chemical injury in male mice

Skeletal muscle has a high regenerative ability and maintains homeostasis by rapidly regenerating from frequent damage caused by intense exercise or trauma. In sports, skeletal muscle damage occurs frequently due to intense exercise, so practical methods to promote skeletal muscle regeneration are required. Recent studies have shown that it may be possible to promote skeletal muscle regeneration through new pathways, such as promoting autophagy and improving mitochondrial function. Spermidine is a type of polyamine, and oral intake of spermidine promotes autophagy and improves mitochondrial function without inhibiting mTOR. Therefore, we evaluate the effects of spermidine intake on skeletal muscle regeneration after injury using a mouse model of cardiotoxin-induced muscle injury. Our results showed no significant change in skeletal muscle wet weight with spermidine intake at all time points. In addition, although spermidine intake significantly increased the mean fiber cross-sectional area 14 days after injury, these effects were not observed at other time points. In addition, we analyzed stem cells, autophagy, mTOR signaling, inflammation, and mitochondria, but no significant effects of spermidine intake were observed at almost all time points and protein expression levels. Therefore, spermidine intake does not affect skeletal muscle regeneration after chemical injury, and if there is any, it is very limited.

Combination of Exogenous Spermidine and Phosphocreatine Efficiently Improved the Quality and Antioxidant Capacity of Cryopreserved Boar Sperm and Reduced Apoptosis-Like Changes

The low resistance of boar sperm to cryopreservation dictates that addition antioxidants and energetic substances to the diluent to improve sperm quality is necessary. This study evaluated the effect of spermidine and phosphocreatine in combination on the quality, antioxidant capacity, and antiapoptotic-like changes capacity of cryopreserved boar sperm based on previous reports. The results showed that the combined application of spermidine and phosphocreatine significantly enhanced the motility, average path velocity, straight-line velocity, curvilinear velocity, beat cross frequency, acrosome integrity, plasma membrane integrity, mitochondrial activity, and DNA integrity compared with the control group (p < 0.05). In addition, the combined application of spermidine and phosphocreatine significantly enhanced the total antioxidant capacity, superoxide dismutase activity, glutathione peroxidase activity, and catalase activity while significantly decreasing malondialdehyde content and hydrogen peroxide content (p < 0.05). Western Blot analysis further showed that spermidine and phosphocreatine significantly decreased the expression of CASP3 and BAX and significantly enhanced the expression of BCL2 (p < 0.05); therefore, the combination of spermidine and phosphocreatine has potentially positive implications for improving the quality of cryopreserved boar sperm.

Stress triggers irritable bowel syndrome with diarrhea through a spermidine-mediated decline in type I interferon

Irritable bowel syndrome with diarrhea (IBS-D) is a common and chronic gastrointestinal disorder that is characterized by abdominal discomfort and occasional diarrhea. The pathogenesis of IBS-D is thought to be related to a combination of factors, including psychological stress, abnormal muscle contractions, and inflammation and disorder of the gut microbiome. However, there is still a lack of comprehensive analysis of the logical regulatory correlation among these factors. In this study, we found that stress induced hyperproduction of xanthine and altered the abundance and metabolic characteristics of Lactobacillus murinus in the gut. Lactobacillus murinus-derived spermidine suppressed the basal expression of type I interferon (IFN)-α in plasmacytoid dendritic cells by inhibiting the K63-linked polyubiquitination of TRAF3. The reduction in IFN-α unrestricted the contractile function of colonic smooth muscle cells, resulting in an increase in bowel movement. Our findings provided a theoretical basis for the pathological mechanism of, and new drug targets for, stress-exposed IBS-D.

Structural insights into polyamine spermidine uptake by the ABC transporter PotD-PotABC

Polyamines, characterized by their polycationic nature, are ubiquitously present in all organisms and play numerous cellular functions. Among polyamines, spermidine stands out as the predominant type in both prokaryotic and eukaryotic cells. The PotD-PotABC protein complex in Escherichia coli, belonging to the adenosine triphosphate-binding cassette transporter family, is a spermidine-preferential uptake system. Here, we report structural details of the polyamine uptake system PotD-PotABC in various states. Our analyses reveal distinct "inward-facing" and "outward-facing" conformations of the PotD-PotABC transporter, as well as conformational changes in the "gating" residues (F222, Y223, D226, and K241 in PotB; Y219 and K223 in PotC) controlling spermidine uptake. Therefore, our structural analysis provides insights into how the PotD-PotABC importer recognizes the substrate-binding protein PotD and elucidates molecular insights into the spermidine uptake mechanism of bacteria.

Spermidine as an epigenetic regulator of autophagy in neurodegenerative disorders

Autophagy is an abnormal protein degradation and recycling process that is impaired in various neurological diseases like Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease. Spermidine is a natural polyamine found in various plant- and meat-based diets that can induce autophagy, and is decreased in various neurodegenerative diseases. It acts on epigenetic enzymes like E1A-binding protein p300, HAT enzymes like Iki3p and Sas3p, and α-tubulin acetyltransferase 1 that modulate autophagy. Histone modifications like acetylation, phosphorylation, and methylation could influence autophagy. Autophagy is epigenetically regulated in various neurodegenerative disorders with many epigenetic enzymes and miRNAs. Polyamine regulation plays an essential role in the disease pathogenesis of AD and PD. Therefore, in this review, we discuss various enzymes and miRNAs involved in the epigenetic regulation of autophagy in neurodegenerative disorders and the role of spermidine as an autophagy enhancer. The alterations in spermidine-mediated regulation of Beclin-1, LC3-II, and p62 genes in AD and other PD-associated enzymes could impact the process of autophagy in these neurodegenerative diseases. With the ever-growing data and such promising effects of spermidine in autophagy, we feel it could be a promising target in this area and worth further detailed studies.

Chemically programmed metabolism drives a superior cell fitness for cartilage regeneration

The rapid advancement of cell therapies underscores the importance of understanding fundamental cellular attributes. Among these, cell fitness-how transplanted cells adapt to new microenvironments and maintain functional stability in vivo-is crucial. This study identifies a chemical compound, FPH2, that enhances the fitness of human chondrocytes and the repair of articular cartilage, which is typically nonregenerative. Through drug screening, FPH2 was shown to broadly improve cell performance, especially in maintaining chondrocyte phenotype and enhancing migration. Single-cell transcriptomics indicated that FPH2 induced a super-fit cell state. The mechanism primarily involves the inhibition of carnitine palmitoyl transferase I and the optimization of metabolic homeostasis. In animal models, FPH2-treated human chondrocytes substantially improved cartilage regeneration, demonstrating well-integrated tissue interfaces in rats. In addition, an acellular FPH2-loaded hydrogel proved effective in preventing the onset of osteoarthritis. This research provides a viable and safe method to enhance chondrocyte fitness, offering insights into the self-regulatory mechanisms of cell fitness.

Spermidine-eIF5A axis is essential for muscle stem cell activation via translational control

Adult skeletal muscle stem cells, also known satellite cells (SCs), are quiescent and activate in response to injury. However, the activation mechanisms of quiescent SCs (QSCs) remain largely unknown. Here, we investigated the metabolic regulation of SC activation by identifying regulatory metabolites that promote SC activation. Using targeted metabolomics, we found that spermidine acts as a regulatory metabolite to promote SC activation and muscle regeneration in mice. Mechanistically, spermidine activates SCs via generating hypusinated eIF5A. Using SC-specific eIF5A-knockout (KO) and Myod-KO mice, we further found that eIF5A is required for spermidine-mediated SC activation by controlling MyoD translation. More significantly, depletion of eIF5A in SCs results in impaired muscle regeneration in mice. Together, the findings of our study define a novel mechanism that is essential for SC activation and acts via spermidine-eIF5A-mediated MyoD translation. Our findings suggest that the spermidine-eIF5A axis represents a promising pharmacological target in efforts to activate endogenous SCs for the treatment of muscular disease.

Long-distance microbial mechanisms impacting cancer immunosurveillance

The intestinal microbiota determines immune responses against extraintestinal antigens, including tumor-associated antigens. Indeed, depletion or gross perturbation of the microbiota undermines the efficacy of cancer immunotherapy, thereby compromising the clinical outcome of cancer patients. In this review, we discuss the long-distance effects of the gut microbiota and the mechanisms governing antitumor immunity, such as the translocation of intestinal microbes into tumors, migration of leukocyte populations from the gut to the rest of the body, including tumors, as well as immunomodulatory microbial products and metabolites. The relationship between these pathways is incompletely understood, in particular the significance of the tumor microbiota with respect to the identification of host and/or microbial products that regulate the egress of bacteria and immunocytes toward tumor beds.

Lysosomal dysfunction in α-synuclein pathology: molecular mechanisms and therapeutic strategies

In orchestrating cell signaling, facilitating plasma membrane repair, supervising protein secretion, managing waste elimination, and regulating energy consumption, lysosomes are indispensable guardians that play a crucial role in preserving intracellular homeostasis. Neurons are terminally differentiated post-mitotic cells. Neuronal function and waste elimination depend on normal lysosomal function. Converging data suggest that lysosomal dysfunction is a critical event in the etiology of Parkinson's disease (PD). Mutations in Glucosylceramidase Beta 1 (GBA1) and leucine-rich repeat kinase 2 (LRRK2) confer an increased risk for the development of parkinsonism. Furthermore, lysosomal dysfunction has been observed in the affected neurons of sporadic PD (sPD) patients. Given that lysosomal hydrolases actively contribute to the breakdown of impaired organelles and misfolded proteins, any compromise in lysosomal integrity could incite abnormal accumulation of proteins, including α-synuclein, the major component of Lewy bodies in PD. Clinical observations have shown that lysosomal protein levels in cerebrospinal fluid may serve as potential biomarkers for PD diagnosis and as signs of lysosomal dysfunction. In this review, we summarize the current evidence regarding lysosomal dysfunction in PD and discuss the intimate relationship between lysosomal dysfunction and pathological α-synuclein. In addition, we discuss therapeutic strategies that target lysosomes to treat PD.

Inflammation primes the murine kidney for recovery by activating AZIN1 adenosine-to-inosine editing

The progression of kidney disease varies among individuals, but a general methodology to quantify disease timelines is lacking. Particularly challenging is the task of determining the potential for recovery from acute kidney injury following various insults. Here, we report that quantitation of post-transcriptional adenosine-to-inosine (A-to-I) RNA editing offers a distinct genome-wide signature, enabling the delineation of disease trajectories in the kidney. A well-defined murine model of endotoxemia permitted the identification of the origin and extent of A-to-I editing, along with temporally discrete signatures of double-stranded RNA stress and adenosine deaminase isoform switching. We found that A-to-I editing of antizyme inhibitor 1 (AZIN1), a positive regulator of polyamine biosynthesis, serves as a particularly useful temporal landmark during endotoxemia. Our data indicate that AZIN1 A-to-I editing, triggered by preceding inflammation, primes the kidney and activates endogenous recovery mechanisms. By comparing genetically modified human cell lines and mice locked in either A-to-I-edited or uneditable states, we uncovered that AZIN1 A-to-I editing not only enhances polyamine biosynthesis but also engages glycolysis and nicotinamide biosynthesis to drive the recovery phenotype. Our findings implicate that quantifying AZIN1 A-to-I editing could potentially identify individuals who have transitioned to an endogenous recovery phase. This phase would reflect their past inflammation and indicate their potential for future recovery.