Recent advances in understanding the mechanisms determining longevity

Life history in Caenorhabditis elegans: from molecular genetics to evolutionary ecology

Life history is defined by traits that reflect key components of fitness, especially those relating to reproduction and survival. Research in life history seeks to unravel the relationships among these traits and understand how life history strategies evolve to maximize fitness. As such, life history research integrates the study of the genetic and developmental mechanisms underlying trait determination with the evolutionary and ecological context of Darwinian fitness. As a leading model organism for molecular and developmental genetics, Caenorhabditis elegans is unmatched in the characterization of life history-related processes, including developmental timing and plasticity, reproductive behaviors, sex determination, stress tolerance, and aging. Building on recent studies of natural populations and ecology, the combination of C. elegans' historical research strengths with new insights into trait variation now positions it as a uniquely valuable model for life history research. In this review, we summarize the contributions of C. elegans and related species to life history and its evolution. We begin by reviewing the key characteristics of C. elegans life history, with an emphasis on its distinctive reproductive strategies and notable life cycle plasticity. Next, we explore intraspecific variation in life history traits and its underlying genetic architecture. Finally, we provide an overview of how C. elegans has guided research on major life history transitions both within the genus Caenorhabditis and across the broader phylum Nematoda. While C. elegans is relatively new to life history research, significant progress has been made by leveraging its distinctive biological traits, establishing it as a highly cross-disciplinary system for life history studies.

Decoding the Role of NEIL1 Gene in DNA Repair and Lifespan: A Literature Review with Bioinformatics Analysis

Longevity, the length of an organism's lifespan, is impacted by environmental factors, metabolic processes, and genetic determinants. The base excision repair (BER) pathway is crucial for maintaining genomic integrity by repairing oxidatively modified base lesions. Nei-like DNA Glycosylase 1 (NEIL1), part of the BER pathway, is vital in repairing oxidative bases in G-rich DNA regions, such as telomeres and promoters. Hence, in this comprehensive review, it have undertaken a meticulous investigation of the intricate association between NEIL1 and longevity. The analysis delves into the multifaceted aspects of the NEIL1 gene, its various RNA transcripts, and the diverse protein isoforms. In addition, a combination of bioinformatic analysis is conducted to identify NEIL1 mutations, transcription factors, and epigenetic modifications, as well as its lncRNA/pseudogene/circRNA-miRNA-mRNA regulatory network. The findings suggest that the normal function of NEIL1 is a significant factor in human health and longevity, with defects in NEIL1 potentially leading to various cancers and related syndromes, Alzheimer's disease, obesity, and diabetes.

Small extracellular vesicles from young plasma reverse age-related functional declines by improving mitochondrial energy metabolism

Recent investigations into heterochronic parabiosis have unveiled robust rejuvenating effects of young blood on aged tissues. However, the specific rejuvenating mechanisms remain incompletely elucidated. Here we demonstrate that small extracellular vesicles (sEVs) from the plasma of young mice counteract pre-existing aging at molecular, mitochondrial, cellular and physiological levels. Intravenous injection of young sEVs into aged mice extends their lifespan, mitigates senescent phenotypes and ameliorates age-associated functional declines in multiple tissues. Quantitative proteomic analyses identified substantial alterations in the proteomes of aged tissues after young sEV treatment, and these changes are closely associated with metabolic processes. Mechanistic investigations reveal that young sEVs stimulate PGC-1α expression in vitro and in vivo through their miRNA cargoes, thereby improving mitochondrial functions and mitigating mitochondrial deficits in aged tissues. Overall, this study demonstrates that young sEVs reverse degenerative changes and age-related dysfunction, at least in part, by stimulating PGC-1α expression and enhancing mitochondrial energy metabolism.

The link between spirituality and longevity

We are facing an inverted demographic pyramid with continuously growing aged populations around the world. However, the advances that prolong physical life not always contemplate its psychological and social dimensions. Longevity is a complex outcome influenced by a wide range of factors, including genetics, lifestyle choices, access to healthcare, socio-economic conditions, and other environmental factors. These factors have been generally considered in the compelling research that seeks the determinants of longevity, particularly those concerning personal lifestyle choices, socioeconomic conditions, and molecular mechanisms proposed to mediate these effects. Nonetheless, fundamental aspects that can affect health and well-being, such as spirituality and religiosity, have been somehow left aside despite numerous epidemiological studies showing that higher levels of spirituality/religiosity are associated with lower risk of mortality, even after adjusting for relevant confounders. Because spirituality/religiosity are dimensions of great value for patients, overlooking them can leave them with feelings of neglect and lack of connection with the health system and with the clinicians in charge of their care. Integrating spirituality and religiosity assessment and intervention programs into clinical care can help each person obtain better and complete well-being and also allowing clinicians to achieve the highest standards of health with holistic, person-centered care. The present narrative review aims to explore the available evidence of a relationship between spirituality/religiosity and longevity and discusses the possible mechanisms that can help explain such relationship.

Evolution of Longevity as a Species-Specific Trait in Mammals

From the evolutionary point of view, the priority problem for an individual is not longevity, but adaptation to the environment associated with the need for survival, food supply, and reproduction. We see two main vectors in the evolution of mammals. One is a short lifespan and numerous offspring ensuring reproductive success (r-strategy). The other one is development of valuable skills in order compete successfully (K-strategy). Species with the K-strategy should develop and enhance specific systems (anti-aging programs) aimed at increasing the reliability and adaptability, including lifespan. These systems are signaling cascades that provide cell repair and antioxidant defense. Hence, any arbitrarily selected long-living species should be characterized by manifestation to a different extent of the longevity-favoring traits (e.g., body size, brain development, sociality, activity of body repair and antioxidant defense systems, resistance to xenobiotics and tumor formation, presence of neotenic traits). Hereafter, we will call a set of such traits as the gerontological success of a species. Longevity is not equivalent to the evolutionary or reproductive success. This difference between these phenomena reaches its peak in mammals due to the development of endothermy and cephalization associated with the cerebral cortex expansion, which leads to the upregulated production of oxidative radicals by the mitochondria (and, consequently, accelerated aging), increase in the number of non-dividing differentiated cells, accumulation of the age-related damage in these cells, and development of neurodegenerative diseases. The article presents mathematical indicators used to assess the predisposition to longevity in different species (including the standard mortality rate and basal metabolic rate, as well as their derivatives). The properties of the evolution of mammals (including the differences between modern mammals and their ancestral forms) are also discussed.

G protein-coupled receptors that influence lifespan of human and animal models

Humanity has always sought to live longer and for this, multiple strategies have been tried with varying results. In this sense, G protein-coupled receptors (GPCRs) may be a good option to try to prolong our life while maintaining good health since they have a substantial participation in a wide variety of processes of human pathophysiology and are one of the main therapeutic targets. In this way, we present the analysis of a series of GPCRs whose activity has been shown to affect the lifespan of animal and human models, and in which we put a special interest in describing the molecular mechanisms involved. Our compilation of data revealed that the mechanisms most involved in the role of GPCRs in lifespan are those that mimic dietary restriction, those related to insulin signaling and the AMPK and TOR pathways, and those that alter oxidative homeostasis and severe and/or chronic inflammation. We also discuss the possibility of using agonist or antagonist drugs, depending on the beneficial or harmful effects of each GPCR, in order to prolong people's lifespan and healthspan.

Footprints in the Sand: Deep Taxonomic Comparisons in Vertebrate Genomics to Unveil the Genetic Programs of Human Longevity

With the modern quality, quantity, and availability of genomic sequencing across species, as well as across the expanse of human populations, we can screen for shared signatures underlying longevity and lifespan. Knowledge of these mechanisms would be medically invaluable in combating aging and age-related diseases. The diversity of longevities across vertebrates is an opportunity to look for patterns of genetic variation that may signal how this life history property is regulated, and ultimately how it can be modulated. Variation in human longevity provides a unique window to look for cases of extreme lifespan within a population, as well as associations across populations for factors that influence capacity to live longer. Current large cohort studies support the use of population level analyses to identify key factors associating with human lifespan. These studies are powerful in concept, but have demonstrated limited ability to resolve signals from background variation. In parallel, the expanding catalog of sequencing and annotation from diverse species, some of which have evolved longevities well past a human lifespan, provides independent cases to look at the genomic signatures of longevity. Recent comparative genomic work has shown promise in finding shared mechanisms associating with longevity among distantly related vertebrate groups. Given the genetic constraints between vertebrates, we posit that a combination of approaches, of parallel meta-analysis of human longevity along with refined analysis of other vertebrate clades having exceptional longevity, will aid in resolving key regulators of enhanced lifespan that have proven to be elusive when analyzed in isolation.

Neurobehavior and neuron damage following prolonged exposure of silver nanoparticles with/without polyvinylpyrrolidone coating in Caenorhabditis elegans

Silver nanoparticles (AgNPs) have become widespread in the environment with increasing industrial applications. But the studies about their potential health risks are far from enough, especially in neurotoxic effects. This study aimed to investigate the neurotoxic effects of longer-term exposure (prolonged exposure for 48 h and chronic exposure for 6 days) of 20nm AgNPs with/without polyvinylpyrrolidone (PVP) coating at low concentrations (0.01-10 mg·L^-1 ) to Caenorhabditis elegans. The results suggested that exposure to AgNPs induced damage to nematode survival, with the longest and relative average life span reduced. Exposure to AgNPs caused neurotoxicity on locomotion behaviors (head thrashes, body bends, pharyngeal pumping frequency, and defecation interval) and sensory perception behaviors (chemotaxis assay and thermotaxis assay), as well as impaired dopaminergic, GABAergic, and cholinergic neurons, except for glutamatergic, based on the alters fluorescence intensity, in a dose- and time-dependent manner. Further investigations suggested that the low-dose AgNPs (0.01-0.1 mg·L^-1 ) exposure raises receptors of GABAergic and dopamine in C. elegans at the genetic level, whereas opposite results were observed at higher doses (1-10 mg·L^-1 ), which implied that AgNPs could cause neurotoxicity by impairing neurotransmitter delivery. The PVP-AgNPs could cause a higher fatality rate and neurotoxicity at the same dose. Notably, AgNPs did not cause any deleterious effect on nematodes at the lowest dose of 0.01 mg·L^-1 . In general, these results suggested that AgNPs possess the neurotoxic potential in C. elegans and provided useful information to understand the neurotoxicity of AgNPs, which would offer an inspiring perspective on the safe application.

The Mitochondrial Permeability Transition: Nexus of Aging, Disease and Longevity

The activity of the mitochondrial permeability transition pore, mPTP, a highly regulated multi-component mega-channel, is enhanced in aging and in aging-driven degenerative diseases. mPTP activity accelerates aging by releasing large amounts of cell-damaging reactive oxygen species, Ca²⁺ and NAD⁺. The various pathways that control the channel activity, directly or indirectly, can therefore either inhibit or accelerate aging or retard or enhance the progression of aging-driven degenerative diseases and determine lifespan and healthspan. Autophagy, a catabolic process that removes and digests damaged proteins and organelles, protects the cell against aging and disease. However, the protective effect of autophagy depends on mTORC2/SKG1 inhibition of mPTP. Autophagy is inhibited in aging cells. Mitophagy, a specialized form of autophagy, which retards aging by removing mitochondrial fragments with activated mPTP, is also inhibited in aging cells, and this inhibition leads to increased mPTP activation, which is a major contributor to neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. The increased activity of mPTP in aging turns autophagy/mitophagy into a destructive process leading to cell aging and death. Several drugs and lifestyle modifications that enhance healthspan and lifespan enhance autophagy and inhibit the activation of mPTP. Therefore, elucidating the intricate connections between pathways that activate and inhibit mPTP, in the context of aging and degenerative diseases, could enhance the discovery of new drugs and lifestyle modifications that slow aging and degenerative disease.

Checkpoint Defects Elicit a WRNIP1-Mediated Response to Counteract R-Loop-Associated Genomic Instability

Conflicts between replication and transcription are a common source of genomic instability, a characteristic of almost all human cancers. Aberrant R-loops can cause a block to replication fork progression. A growing number of factors are involved in the resolution of these harmful structures and many perhaps are still unknown. Here, we reveal that the Werner interacting protein 1 (WRNIP1)-mediated response is implicated in counteracting aberrant R-loop accumulation. Using human cellular models with compromised Ataxia-Telangiectasia and Rad3-Related (ATR)-dependent checkpoint activation, we show that WRNIP1 is stabilized in chromatin and is needed for maintaining genome integrity by mediating the Ataxia Telangiectasia Mutated (ATM)-dependent phosphorylation of Checkpoint kinase 1 (CHK1). Furthermore, we demonstrated that loss of Werner Syndrome protein (WRN) or ATR signaling leads to formation of R-loop-dependent parental ssDNA upon mild replication stress, which is covered by Radiorestistance protein 51 (RAD51). We prove that Werner helicase-interacting protein 1 (WRNIP1) chromatin retention is also required to stabilize the association of RAD51 with ssDNA in proximity of R-loops. Therefore, in these pathological contexts, ATM inhibition or WRNIP1 abrogation is accompanied by increased levels of genomic instability. Overall, our findings suggest a novel function for WRNIP1 in preventing R-loop-driven genome instability, providing new clues to understand the way replication–transcription conflicts are handled.