Biology subjects

Morandini, F.

Publications and source records attributed to Morandini, F..

6 recordsLinked to original sources

bioRxiv2025

Fucoidans are senotherapeutics that enhance SIRT6-dependent DNA repair

Aging is marked by the accumulation of senescent cells (SnCs), which contribute to tissue dysfunction and age-related diseases. Senotherapeutics, including senolytics which specifically induce lysis of SnCs and senomorphics, which suppress the senescence phenotype, represent promising therapeutic interventions for mitigating age-related pathologies and extending healthspan. Using a phenotypic-based senescent cell screening assay, we identified fucoidans, a class of sulfated polysaccharides derived from brown algae and seaweed, as novel senotherapeutics. In particular, fucoidan from Fucus vesiculosus (Fucoidan-FV) displayed potent senomorphic activity in different types of SnCs, reduced senescence in multiple tissues in aged mice, and extended healthspan in a mouse model of accelerated aging. Fucoidan-FV also enhanced the deacetylation and mono-ADP-ribosylation (mADPr) activity of SIRT6 and improved DNA repair and reduced senescence, in part, through SIRT6-dependent pathways. In addition, Fucoidan-FV downregulated genes associated with inflammation, Wnt signaling, and ECM remodeling pathways in SnCs and increased expression of genes involved with DNA repair. These findings support the translational potential of fucoidans as novel senotherapeutics that also are able to improve SIRT6-mediated DNA repair.

cell biology↗

bioRxiv2025

SIRT6 activator fucoidan extends healthspan and lifespan in aged wild-type mice

SIRT6 is a protein deacylase, deacetylase, and mono-ADP-ribosylase (mADPr) regulating biological pathways important for longevity including DNA repair and silencing of LINE1 retrotransposons. SIRT6 knockout mice die by 30 days of age, whereas SIRT6 overexpression increases lifespan in male mice. Finding safe pharmacological activators of SIRT6 would have clinical benefits. Fucoidan, a polysaccharide purified from brown seaweed, has been identified as an activator of SIRT6 deacetylation activity. Here, we show that fucoidan also activates SIRT6 mADPr activity, which was shown to be elevated in certain human centenarians. Administering fucoidan to aged mice led to a significant increase in median lifespan in male mice. Both male and female mice demonstrated a marked reduction in frailty and epigenetic age. Fucoidan-treated mice showed repression of LINE1 elements suggesting that the beneficial effects of fucoidan are mediated, at least in part, by SIRT6. As brown seaweed rich in fucoidan is a popular food item in South Korea and Japan, countries with the highest life expectancy, we propose that fucoidan supplementation should be explored as a safe strategy for activating SIRT6 and improving human healthspan and lifespan.

molecular biology↗

bioRxiv2024

cGAS deficient mice display premature aging associated with de-repression of LINE1 elements and inflammation

Aging-associated inflammation, or inflammaging" is a driver of multiple age-associated diseases. Cyclic GMP-AMP Synthase (cGAS) is a cytosolic DNA sensor that functions to activate interferon response upon detecting viral DNA in the cytoplasm. cGAS contributes to inflammaging by responding to endogenous signals such as damaged DNA or LINE1 (L1) cDNA which forms in aged cells. While cGAS knockout mice are viable their aging has not been examined. Unexpectedly, we found that cGAS knockout mice exhibit accelerated aging phenotype associated with induction of inflammation. Transcription of L1 elements was increased in both cGAS knockout mice and in cGAS siRNA knockdown cells associated with high levels of cytoplasmic L1 DNA and expression of ORF1 protein. Cells from cGAS knockout mice showed increased chromatin accessibility and decreased DNA methylation on L1 transposons. Stimulated emission depletion microscopy (STED) showed that cGAS forms nuclear condensates that co-localize with H3K9me3 heterochromatin marks, and H3K9me3 pattern is disrupted in cGAS knockout cells. Taken together these results suggest a previously undescribed role for cGAS in maintaining heterochromatin on transposable elements. We propose that loss of cGAS leads to loss of chromatin organization, de-repression of transposable elements and induction of inflammation resulting in accelerated aging.

cell biology↗

bioRxiv2024

Transposable element methylation state predicts age and disease

Transposable elements (TEs) are DNA sequences that expand selfishly in the genome, possibly causing severe cellular damage. While normally silenced, TEs have been shown to activate during aging. DNA methylation is one of the main mechanisms by which TEs are silenced and has been used to train highly accurate age predictors. Yet, one common criticism of such predictors is that they lack interpretability. In this study, we investigate the changes in TE methylation that occur during human aging. We find that evolutionarily young LINE1s (L1s), the only known TEs capable of autonomous transposition in humans, undergo the fastest loss of methylation, suggesting an active mechanism of de-repression. We then show that accurate age predictors can be trained on both methylation of individual TE copies and average methylation of TE families genome wide. Lastly, we show that while old L1s gradually lose methylation during the entire lifespan, demethylation of young L1s only happens late in life and is associated with cancer.

genomics↗

bioRxiv2023

Initiation phase cellular reprogramming ameliorates DNA damage in the ERCC1 mouse model of premature aging.

Unlike aged somatic cells, which exhibit a decline in molecular fidelity and eventually reach a state of replicative senescence, pluripotent stem cells can indefinitely replenish themselves while retaining full homeostatic capacity. The conferment of beneficial-pluripotency related traits via in vivo partial cellular reprogramming (IVPR) significantly extends lifespan and restores aging phenotypes in mouse models. Although the phases of cellular reprogramming are well characterized, details of the rejuvenation processes are poorly defined. To understand whether epigenetic reprogramming can ameliorate DNA damage, we created reprogrammable accelerated aging mouse model with an ERCC1 mutation. Importantly, using enhanced partial reprogramming by combining small molecules with the Yamanaka factors, we observed potent reversion of DNA damage, significant upregulation of multiple DNA damage repair processes, and restoration of the epigenetic clock. In addition, we present evidence that pharmacological inhibition of ALK5 and ALK2 receptors in TGFb pathway is able to phenocopy some benefits including epigenetic clock restoration suggesting a role in the mechanism of rejuvenation by partial reprogramming.

cell biology↗

bioRxiv2022

Development of a novel aging clock based on chromatin accessibility

The establishment of aging clocks based on age-associated changes in DNA methylation has highlighted the strong link between epigenetic alterations and aging. However, the connection between DNA methylation changes at clock sites and their effect on cellular function remains unclear. We hypothesize that chromatin accessibility, a readout that integrates multiple epigenetic mechanisms, may connect epigenetic changes with downstream biological effects. To investigate this hypothesis, we generated chromatin accessibility profiles from peripheral blood mononuclear cells (PBMCs) of 157 human donors and construct a novel aging clock with a median absolute error on prediction of 5.69 years. Moreover, by comparing our chromatin accessibility data to matched transcriptomic profiles, we show that the genomic sites selected for the prediction of age based on chromatin accessibility undergo transcriptional changes during aging. This chromatin accessibility clock could therefore be used to investigate the direct effect of aged epigenetic states on cellular function.

genomics↗