ATF-4 and hydrogen sulfide signalling mediate longevity from inhibition of translation or mTORC1 [preprint]

Inhibition of mTORC1 (mechanistic target of rapamycin 1) slows ageing, but mTORC1 supports fundamental processes that include protein synthesis, making it critical to elucidate how mTORC1 inhibition increases lifespan. Under stress conditions, the integrated stress response (ISR) globally suppresses protein synthesis, resulting in preferential translation of the transcription factor ATF-4. Here we show in C. elegans that the ATF-4 transcription program promotes longevity and that ATF-4 upregulation mediates lifespan extension from mTORC1 inhibition. ATF-4 activates canonical anti-ageing mechanisms but also increases expression of transsulfuration enzymes to promote hydrogen sulfide (H2S) production. ATF-4-induced H2S production mediates longevity and stress resistance from C. elegans mTORC1 suppression, and ATF4 drives H2S production in mammalian dietary restriction. This H2S boost increases protein persulfidation, a protective modification of redox-reactive cysteines. Increasing H2S levels, or enhancing mechanisms that H2S modulates through persulfidation, may represent promising strategies for mobilising therapeutic benefits of the ISR or mTORC1 inhibition

The extracellular matrix phenome across species

Extracellular matrices are essential for cellular and organismal function. Recent genome-wide and phenome-wide association studies started to reveal a broad spectrum of phenotypes associated with genetic variants. However, the phenome or spectrum of all phenotypes associated with genetic variants in extracellular matrix genes is unknown. Here, we analyzed over two million recorded genotype-to-phenotype relationships across multiple species to define their extracellular matrix phenomes. By using the previously defined matrisomes of humans, mice, zebrafish, Drosophila, and C. elegans, we found that the extracellular matrix phenome comprises of 3–10% of the entire phenome. Collagens (COL1A1, COL2A1) and fibrillin (FBN1) are each associated with >150 distinct phenotypes in humans, whereas collagen COL4A1, Wnt- and sonic hedgehog (shh) signaling are predominantly associated in other species. We determined the phenotypic fingerprints of matrisome genes and found that MSTN, CTSD, LAMB2, HSPG2, and COL11A2 and their corresponding orthologues have the most phenotypes across species. Out of the 42,551 unique matrisome genotype-to-phenotype relationships across the five species with defined matrisomes, we have constructed interaction networks to identify the underlying molecular components connecting with orthologues phenotypes and with novel phenotypes. Thus, our networks provide a framework to predict unassessed phenotypes and their potential underlying molecular interactions. These frameworks inform on matrisome genotype-to-phenotype relationships and potentially provide a sophisticated choice of biological model system to study human phenotypes and diseases.ISSN:2590-028

Longevity interventions temporally scale healthspan in Caenorhabditis elegans

Human centenarians and longevity mutants of model organisms show lower incidence rates of late-life morbidities than the average population. However, whether longevity is caused by a compression of the portion of life spent in a state of morbidity, i.e., “sickspan,” is highly debated even in isogenic Caenorhabditis elegans. Here, we developed a microfluidic device that employs acoustophoretic force fields to quantify the maximum muscle strength and dynamic power in aging C. elegans. Together with different biomarkers for healthspan, we found a stochastic onset of morbidity, starting with a decline in dynamic muscle power and structural integrity, culminating in frailty. Surprisingly, we did not observe a compression of sickspan in longevity mutants but instead observed a temporal scaling of healthspan. Given the conservation of these longevity interventions, this raises the question of whether the healthspan of mammalian longevity interventions is also temporally scaled.ISSN:2589-004

Extracellular Matrix Dynamics as an Emerging yet Understudied Hallmark of Aging and Longevity

The biomechanical properties of extracellular matrices (ECM) and their consequences for cellular homeostasis have recently emerged as a driver of aging. Here we review the age-dependent deterioration of ECM in the context of our current understanding of the aging processes. We discuss the reciprocal interactions of longevity interventions with ECM remodeling. And the relevance of ECM dynamics captured by the matrisome and the matreotypes associated with health, disease, and longevity. Furthermore, we highlight that many established longevity compounds promote ECM homeostasis. A large body of evidence for the ECM to qualify as a hallmark of aging is emerging, and the data in invertebrates is promising. However, direct experimental proof that activating ECM homeostasis is sufficient to slow aging in mammals is lacking. We conclude that further research is required and anticipate that a conceptual framework for ECM biomechanics and homeostasis will provide new strategies to promote health during aging.ISSN:2152-525

Lifespan-Associated Gene Expression Signatures of Recombinant BXD Mice Implicates Coro7 and Set in Longevity

Although genetic approaches have identified key genes and pathways that promote longevity, systems-level approaches are less utilized. Here, we took advantage of the wealth of omics data characterizing the BXD family of mice. We associated transcript and peptide levels across five tissues from both female and male BXD isogenic lines with their median lifespan. We identified over 5000 genes that showed a longevity correlation in a given tissue. Surprisingly, we found less than 1% overlap among longevity-correlating genes across tissues and sex. These 1% shared genes consist of 51 genes, of which 13 have been shown to alter lifespan. Only two genes -Coro7 and Set- showed a longevity correlation in all tissues and in both sexes. While differential regulation of aging across tissues and sex has been reported, our systems-level analysis reveals two unique genes that may promote healthy aging in unique sex- and tissue-agnostic manner.ISSN:1664-802

Youthful and age-related matreotypes predict drugs promoting longevity

The identification and validation of drugs that promote health during aging ("geroprotectors") are key to the retardation or prevention of chronic age-related diseases. Here, we found that most of the established pro-longevity compounds shown to extend lifespan in model organisms also alter extracellular matrix gene expression (i.e., matrisome) in human cell lines. To harness this observation, we used age-stratified human transcriptomes to define the age-related matreotype, which represents the matrisome gene expression pattern associated with age. Using a "youthful" matreotype, we screened in silico for geroprotective drug candidates. To validate drug candidates, we developed a novel tool using prolonged collagen expression as a non-invasive and in-vivo surrogate marker for Caenorhabditis elegans longevity. With this reporter, we were able to eliminate false-positive drug candidates and determine the appropriate dose for extending the lifespan of C. elegans. We improved drug uptake for one of our predicted compounds, genistein, and reconciled previous contradictory reports of its effects on longevity. We identified and validated new compounds, tretinoin, chondroitin sulfate, and hyaluronic acid, for their ability to restore age-related decline of collagen homeostasis and increase lifespan. Thus, our innovative drug screening approach-employing extracellular matrix homeostasis-facilitates the discovery of pharmacological interventions promoting healthy aging.ISSN:1474-9718ISSN:1474-9728ISSN:1474-972

Controllable generation and encapsulation of alginate fibers using droplet-based microfluidics

Herein we demonstrate the segmentation of alginate solution streams to generate alginate fibers of precisely controllable lengths between 200 and 1000 μm.</p

The Human Extracellular Matrix Diseasome Reveals Genotype–Phenotype Associations with Clinical Implications for Age-Related Diseases

The extracellular matrix (ECM) is earning an increasingly relevant role in many disease states and aging. The analysis of these disease states is possible with the GWAS and PheWAS methodologies, and through our analysis, we aimed to explore the relationships between polymorphisms in the compendium of ECM genes (i.e., matrisome genes) in various disease states. A significant contribution on the part of ECM polymorphisms is evident in various types of disease, particularly those in the core-matrisome genes. Our results confirm previous links to connective-tissue disorders but also unearth new and underexplored relationships with neurological, psychiatric, and age-related disease states. Through our analysis of the drug indications for gene–disease relationships, we identify numerous targets that may be repurposed for age-related pathologies. The identification of ECM polymorphisms and their contributions to disease will play an integral role in future therapeutic developments, drug repurposing, precision medicine, and personalized care

Assessing Collagen Deposition During Aging in Mammalian Tissue and in Caenorhabditis elegans

ISSN:1064-3745ISSN:1940-602

Youthful and age-related matreotypes predict drugs promoting longevity

The identification and validation of drugs that promote health during aging (‘geroprotectors’) is key to the retardation or prevention of chronic age-related diseases. Here we found that most of the established pro-longevity compounds shown to extend lifespan in model organisms also alter extracellular matrix gene expression (i.e., matrisome) in human cell lines. To harness this novel observation, we used age-stratified human transcriptomes to define the age-related matreotype, which represents the matrisome gene expression pattern associated with age. Using a ‘youthful’ matreotype, we screened in silico for geroprotective drug candidates. To validate drug candidates, we developed a novel tool using prolonged collagen expression as a non-invasive and in-vivo surrogate marker for C. elegans longevity. With this reporter, we were able to eliminate false positive drug candidates and determine the appropriate dose for extending the lifespan of C. elegans. We improved drug uptake for one of our predicted compounds, genistein, and reconciled previous contradictory reports of its effects on longevity. We identified and validated new compounds, tretinoin, chondroitin sulfate, and hyaluronic acid, for their ability to restore age-related decline of collagen homeostasis and increase lifespan. Thus, our innovative drug screening approach - employing extracellular matrix homeostasis - facilitates the discovery of pharmacological interventions promoting healthy aging