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The pathways that impact longevity in the wake of dietary restriction (DR) remain still ill-defined. Most studies have focused on nutrient limitation and perturbations of energy metabolism. We showed that the L-threonine was elevated in Caenorhabditis elegans under DR, and that L-threonine supplementation increased its healthspan. Using metabolic and transcriptomic profiling in worms that were fed with RNAi to induce loss of key candidate mediators. L-threonine supplementation and loss-of-threonine dehydrogenaseincreased the healthspan by attenuating ferroptosis in a ferritin-dependent manner. Transcriptomic analysis showed that FTN-1 encoding ferritin was elevated, implying FTN-1 is an essential mediator of longevity promotion. Organismal ferritin levels were positively correlated with chronological aging and L-threonine supplementation protected against age-associated ferroptosis through the DAF-16 and HSF-1 pathways. Our investigation uncovered the role of a distinct and universal metabolite, L-threonine, in DR-mediated improvement in organismal healthspan, suggesting it could be an effective intervention for preventing senescence progression and age-induced ferroptosis. How dietary restriction increases longevity is still not fully understood. Here, the authors demonstrate that L-threonine is an essential mediator of dietary restriction that prevents age-induced ferroptosis and that dietary supplementation promotes healthy ageing.

Airborne fine dust particles (FDPs) have been identified as major toxins in air pollution that threaten human respiratory health. While searching for an anti-FDP reagent, we found that green tea extract (GTE) and fractions rich in flavonol glycosides (FLGs) and crude tea polysaccharides (CTPs) had protective effects against FDP-stimulated cellular damage in the BEAS-2B airway epithelial cell line. The GTE, FLGs, and CTPs significantly increased viability and lowered oxidative stress levels in FDP-treated cells. Combined treatment with GTE, FLGs, and CTPs also exerted synergistic protective effects on cells and attenuated FDP-induced elevations in inflammatory gene expression. Moreover, the green tea components increased the proportion of ciliated cells and upregulated ciliogenesis in the airway in FDP-stimulated BEAS-2B cells. Our findings provide insights into how natural phytochemicals protect the airway and suggest that green tea could be used to reduce FDP-induced airway damage as an ingredient in pharmaceutical, nutraceutical, and also cosmeceutical products.

The mechanisms underlying the impact of probiotic supplementation on health remain largely elusive. While previous studies primarily focus on the discovery of novel bioactive bacteria and alterations in the microbiome environment to explain potential probiotic effects, our research delves into the role of living Lactiplantibacillus (formerly known as Lactobacillus) and their conditioned media, highlighting that only the former, not dead bacteria, enhance the healthspan of Caenorhabditis elegans (C. elegans) . To elucidate the underlying mechanisms, we conduct transcriptomic profiling through RNA-seq analysis in C. elegans exposed to GTB1, a strain of Lactiplantibacillus plantarum or 3-phenyllactic acid (PLA), mimicking the presence of key candidate metabolites of GTB1 and evaluating healthspan. Our findings reveal that PLA treatment significantly extends the healthspan of C. elegans by promoting energy metabolism and stress resilience in a SKN-1/ATFS-1-dependent manner. Moreover, PLA-mediated longevity is associated with a novel age-related parameter, the Healthy Aging Index (HAI), introduced in this study, which comprises healthspan-related factors such as motility, oxygen consumption rate (OCR), and ATP levels. Extending the relevance of our work to humans, we observe an inverse correlation between blood PLA levels and physical performance in patients with sarcopenia, when compared to age-matched non-sarcopenic controls. Our investigation thus sheds light on the pivotal role of the metabolite PLA in probiotics-mediated enhancement of organismal healthspan, and also hints at its potential involvement in age-associated sarcopenia. These findings warrant further investigation to delineate PLA’s role in mitigating age-related declines in healthspan and resilience to external stressors. The mechanisms underlying the impact of probiotic supplementation on health remain largely elusive. Here, the authors explore the mechanisms through which living Lactiplantibacillus enhance the healthspan of Caenorhabditis elegans (C. elegans).

Age-associated immunological dysfunction (immunosenescence) is closely linked to perturbation of the gut microbiota. Here, we investigated whether syringaresinol (SYR), a polyphenolic lignan, modulates immune aging and the gut microbiota associated with this effect in middle-aged mice. Compared with age-matched control mice, SYR treatment delayed immunosenescence by enhancing the numbers of total CD3 + T cells and naïve T cells. SYR treatment induced the expression of Bim as well as activation of FOXO3 in Foxp3 + regulatory T cells (Tregs). Furthermore, SYR treatment significantly enhanced the Firmicutes / Bacteroidetes ratio compared with that in age-matched controls by increasing beneficial bacteria, Lactobacillus and Bifidobacterium , while reducing the opportunistic pathogenic genus, Akkermansia . In addition, SYR treatment reduced the serum level of lipopolysaccharide-binding protein, an inflammatory marker, and enhanced humoral immunity against influenza vaccination to the level of young control mice. Taken together, these findings suggest that SYR may rejuvenate the immune system through modulation of gut integrity and microbiota diversity as well as composition in middle-aged mice, which may delay the immunosenescence associated with aging.

ABSTRACT Hematopoietic stem cell transplantation (HSCT) profoundly disrupts the gut microbiome and metabolome, which in turn influence immune‐related complications and patient outcomes. To systematically characterize these perturbations, we performed a longitudinal analysis of fecal microbiota composition and metabolite profiles in HSCT recipients at three critical timepoints: pre‐transplant (T1), peri‐transplant (T2), and post‐transplant (T3). We observed that reduced microbial diversity at T1 and T3 was strongly associated with increased incidence of graft‐versus‐host disease (GVHD), progressive disease (PD), and decreased overall survival (OS). Metabolomic profiling revealed a significant decline in short‐chain fatty acids (SCFAs), particularly acetate, from T1 to T2, which correlated with adverse clinical outcomes including GVHD, diarrhea, PD, and lower OS. Elevated levels of uric acid at T2 were predictive of GVHD onset, while decreased 1‐phenylethylamine was linked to transplant‐associated diarrhea. Furthermore, enrichment of beneficial bacterial taxa such as Lachnospiraceae and Ruminococcaceae was associated with improved survival. Together, these findings highlight the gut microbiome–metabolome axis as a dynamic biomarker for HSCT prognosis. This integrated insight offers potential avenues for microbiota‐targeted diagnostics and interventions aimed at mitigating transplant‐related complications and improving patient survival. • Whole fecal analysis generated the distinct signature of the gut microbiome and metabolome for HSCT in subjects with time point among generally 59 individuals. • Reduced microbiota diversity in period of HSCT is linked to increased complications, GVHD, and NF with PD. • SPMs are meaningful target for perspectives, and acetate represents close relation with overall survival of HSCT patients.

Aging is marked by a decline in tissue integrity, particularly in skin and muscle, driven by oxidative stress and extracellular matrix (ECM) degradation. Superoxide dismutase 1 (SOD1) deficiency exacerbates these processes, accelerating atrophy. Matrix metalloproteinase‐2 (MMP‐2), a key enzyme in ECM breakdown, targets collagen type XVII (COLXVII), which is critical for tissue structure and stability. In this study, we investigated the role of MMP‐2 in SOD1‐deficient models and assessed the therapeutic potential of its inhibition. To assess the impact of MMP inhibition on wound healing and skin atrophy, we applied batimastat, a broad‐spectrum MMP inhibitor, to Sod1‐deficient mice. While batimastat inhibits multiple MMPs, including MMP‐2, MMP‐9, and MMP‐14, its application allows us to evaluate the general role of MMP activity in SOD1‐related ECM degradation and repair processes. Using Sod1/Mmp2 double‐knockout mice and the MMP inhibitor batimastat, we observed that MMP‐2 deletion restored skin thickness, increased COLXVII expression, and improved wound healing. Batimastat application yielded similar benefits, reversing skin atrophy and enhancing repair. In muscle tissue, MMP‐2 inhibition restored muscle mass and function, with parallel improvements in SOD1 mutant Caenorhabditis elegans. Preservation of COLXVII emerged as a critical mechanism, significantly mitigating SOD1‐related tissue degeneration. These findings highlight MMP‐2's pivotal role in senescence‐associated tissue atrophy and underscore the therapeutic potential of targeting the SOD1‒MMP‐2‒COLXVII axis to combat age‐related tissue degeneration. Our work identifies a novel role for MMP‐2 in driving senescence‐associated skin and muscle degeneration through ECM degradation. We demonstrate that inhibiting MMP‐2 activity restores tissue integrity by preserving COLXVII, revealing a new therapeutic pathway for combating oxidative stress‐induced tissue aging. Using both mammalian and nematode models, we provide robust evidence that targeting the SOD1‒MMP‐2‒COLXVII axis can reverse aging‐related structural and functional declines, offering translational potential for clinical intervention in age‐related disorders.

The skin of an organism is affected by various environmental factors and fights against aging stress via mechanical and biochemical responses. Photoaging induced by ultraviolet B (UVB) irradiation is common and is the most vital factor in the senescence phenotype of skin, and so, suppression of UVB stress-induced damage is critical. To lessen the UVB-induced hyperimmune response and hyperpigmentation, we investigated the ameliorative effects of intense pulsed light (IPL) treatment on the photoaged phenotype of skin cells. Normal human epidermal keratinocytes and human epidermal melanocytes were exposed to 20 mJ/cm2 of UVB. After UVB irradiation, the cells were treated with green (525–530 nm) and yellow (585–592 nm) IPL at various time points prior to the harvest step. Subsequently, various signs of excessive immune response, including expression of proinflammatory and melanogenic genes and proteins, cellular oxidative stress level, and antioxidative enzyme activity, were examined. We found that IPL treatment reduced excessive cutaneous immune reactions by suppressing UVB-induced proinflammatory cytokine expression. IPL treatment prevented hyperpigmentation, and combined treatment with green and yellow IPL synergistically attenuated both processes. IPL treatment may exert protective effects against UVB injury in skin cells by attenuating inflammatory cytokine and melanogenic gene overexpression, possibly by reducing intracellular oxidative stress. IPL treatment also preserves antioxidative enzyme activity under UVB irradiation. This study suggests that IPL treatment is a useful strategy against photoaging, and provides evidence supporting clinical approaches with non-invasive light therapy.

Platinum nanoparticle (Pt-np) species are superoxide dismutase/catalase mimetics and also have an activity similar to that of mitochondrial electron transport complex I. To examine if this complex I-like activity functions in vivo, we studied the effects of Pt-nps on the lifespan of a mitochondrial complex I-deficient Caenorhabditis elegans mutant, nuo-1 (LB25) compared with wild-type N2. We synthesized a fusion protein of a cell-penetrating peptide, human immunodeficiency virus-1 TAT (48-60), C-terminally linked to a peptide with a high affinity to platinum (GRKKRRQRRRPPQ-DRTSTWR). Pt-nps were functionalized by conjugation with this fusion protein at a 1:1 ratio of TAT-PtBP to Pt atoms. Adult worms were treated with conjugated Pt-nps for 10 days. The mean lifespan of untreated N2 and LB25 was 19.6 ± 0.4 and 11.8 ± 0.3 days, respectively. Using 5 μM of conjugated Pt-nps, the lifespan of N2 and LB25 was maximally extended. This maximal lifespan extension of LB25 was 31.9 ± 2.6%, which was significantly greater than that of N2 (21.1 ± 1.7%, P < 0.05 by Student's t-test). Internalization of Pt into the whole body and mitochondria was similar between these two strains. Excessive accumulation of reactive oxygen species was not observed in the cytosol or mitochondria of untreated LB25. Treatment for five days with 5 μM conjugated Pt-nps decreased cytosolic and mitochondrial reactive oxygen species in N2 and LB25 to a similar extent. The ratio of [NAD(+)]/[NADH] was very low in the whole body and mitochondria of control LB25. After five days of treatment with 5 μM conjugated Pt-nps, the ratio of [NAD(+)]/[NADH] was increased in N2 and LB25. However, the degree of the increase was much higher in LB25 than in N2. Pt-nps function as NADH oxidase and recover the [NAD(+)]/[NADH] ratio in LB25, leading to effective extension of the lifespan of LB25.

Demands for safe depigmentation compounds are constantly increasing in the pharmaceutical and cosmetic industry, since the numerous relevant compounds reported to date have shown undesirable side effects or low anti-melanogenic effects. In this study, we reported three novel inhibitors of tyrosinase, which is the key enzyme in melanogenesis, identified using docking-based high throughput virtual screening of an in-house natural compound library followed by mushroom tyrosinase inhibition assay. Of the three compounds, gallacetophenone showed high anti-melanogenic effect in both human epidermal melanocytes and a 3D human skin model, MelanoDerm. The inhibitory effect of gallacetophenone on tyrosinase was elucidated by computational molecular modeling at the atomic level. Binding of gallacetophenone to the active site of tyrosinase was found to be stabilized by hydrophobic interactions with His367, Ile368, and Val377; hydrogen bonding with Ser380 and a water molecule bridging the copper ions. Thus, our results strongly suggested gallacetophenone as an anti-melanogenic ingredient that inhibits tyrosinase.

Forkhead box-O (FoxO) family transcriptional factors control the expression of many genes involved in a variety of cellular processes. Melanogenesis is an oxidizing process; therefore, many antioxidants are used to inhibit melanin production. However, their mechanism of action is poorly understood. In this study, we investigated the role of FoxO3a, which is a key factor in oxidative stress–related cellular responses in melanogenesis. When FoxO3a expression was inhibited, the expression of melanogenic genes and melanin levels increased. In contrast, the overexpression of wild-type FoxO3a and the increased nuclear translocation induced by the phosphoinositide 3-kinase inhibitors or by Akt inhibition reversed these phenomena. This effect was not observed when FoxO3a harbored a deletion in the nuclear localization signal, indicating that its nuclear translocation is important for the regulation of melanogenesis. When antioxidants such as vitamin C, N-acetylcysteine, and Trolox were applied to MNT1 cells, melanin levels decreased in parallel with FoxO3a nuclear translocation, and this effect disappeared with FoxO3a-directed small interfering RNA treatment. Because FoxO3a orchestrates the expression of many genes in order to regulate cellular phenotypes in a variety of environmental states, this gene, a factor involved in melanogenesis regulation, may represent a good target for studying antimelanogenic signaling pathways and for designing pharmacological or antimelanogenic agents that regulate melanin synthesis.