Improvements in hygiene and health management have driven significant increases in human lifespan over the last 50 years. Frustratingly however, this extension of lifespan has not been matched by equivalent improvements in late-life health, not least due to the global pandemic in type-2 diabetes, obesity and cardiovascular disease, all ageing-associated conditions exacerbated and accelerated by widespread adoption of the high calorie Western diet (HCD). Recently, evidence has begun to emerge that parasitic worm infection might protect against such ageing-associated co-morbidities, as a serendipitous side-effect of their evolution of pro-survival, anti-inflammatory mechanisms. As a novel therapeutic strategy, we have therefore investigated the potential of ES-62, an anti-inflammatory secreted product of the filarial nematode Acanthocheilonema viteae, to improve healthspan (the period of life before diseases of ageing appear) by targeting the chronic inflammation that drives metabolic dysregulation underpinning ageing-induced ill-health. We administered ES-62 subcutaneously (at a dose of 1 μg/week) to C57BL/6J mice undergoing HCD-accelerated ageing throughout their lifespan, while subjecting the animals to analysis of 120 immunometabolic responses at various time-points. ES-62 improved a number of inflammatory parameters, but markedly, a range of pathophysiological, metabolic and microbiome parameters of ageing were also successfully targeted. Notably, ES-62-mediated promotion of healthspan in male and female HCD-mice was associated with different mechanisms and reflecting this, machine learning modelling identified sex-specific signatures predictive of ES-62 action against HCD-accelerated ageing. Remarkably, ES-62 substantially increased the median survival of male HCD-mice. This was not the case with female animals and unexpectedly, this difference between the two sexes could not be explained in terms of suppression of the chronic inflammation driving ageing, as ES-62 tended to be more effective in reducing this in female mice. Rather, the difference appeared to be associated with ES-62's

We are currently in the midst of a revolution in ageing research, with several dietary, genetic and pharmacological interventions now known to modulate ageing in model organisms. Excitingly, these interventions also appear to have beneficial effects on late-life health. For example, dietary restriction (DR) has been shown to slow the incidence of age-associated cardiovascular disease, metabolic disease, cancer and brain ageing in non-human primates and has been shown to improve a range of health indices in humans. While the idea that DR's ability to extend lifespan is often thought of as being universal, studies in a range of organisms, including yeast, mice and monkeys, suggest that this may not actually be the case. The precise reasons underlying these differential effects of DR on lifespan are currently unclear, but genetic background may be an important factor in how an individual responds to DR. Similarly, recent findings also suggest that the responsiveness of mice to specific genetic or pharmacological interventions that modulate ageing may again be influenced by genetic background. Consequently, while there is a clear driver to develop interventions to improve late-life health and vitality, understanding precisely how these act in response to particular genotypes is critical if we are to translate these findings to humans. We will consider of the role of genetic background in the efficacy of various lifespan interventions and discuss potential routes of utilising genetic heterogeneity to further understand how particular interventions modulate lifespan and healthspan.

TejJ114 (see Figure 1 for schematic outlining our original predictions). 0.1mM EGTA, 0.2% BSA (pH 7.4)), as set out in protocols previously described [58]. 208The muscle was subsequently rinsed three times in 1ml of fresh isolation buffer, and Results 318Mitochondrial oxygen consumption rates (OCR) within isolated liver 319 mitochondria under all conditions studied ( Fig. 2A) were unaffected by 10 months of 320 40% DR in strain TejJ89 relative to AL controls. A similar lack of a DR effect on 321 hepatic respiratory capacities was observed in strain TejJ48 (Fig. 2B). In contrast, 322DR in strain TejJ114 (Fig. 2C) under DR (Fig. S2H). 345Total hepatic protein levels of PGC-1α (Fig. 5A), a key transcriptional co-346 activator linked to mitochondrial metabolism and biogenesis, was unaltered by 347 treatment or strain, with both nuclear (Fig. 5B) and cytoplasmic (Fig. 5C) PGC-1α 348 levels likewise unaffected. Similarly, mitochondrial transcription factor A (TFAM), a 349 key activator of mitochondrial transcription, was unaffected by DR or strain (Fig. 5D). 350We then examined various OXPHOS complexes within liver, but again observed no we then went on to investigate whether DR induced mitonuclear protein imbalance and UPR mt by firstly calculating the ratio of nuclear encoded SDHB to mitochondrially 355 encoded MTCO1 as previously described [45]. We observed no effect of either 356 treatment or strain on mitochondrial nuclear imbalance ( Fig. 6A-C). No differences 357were observed between either treatment groups or strains in the mitochondrial 358 chaperone HSP60 (Fig. 6D), but a significant reduction in hepatic HSP90 (Fig. 6E) 359was observed in strain TejJ114 under DR (t=2.267, p=0.045) relative to AL controls. 360In order to determine whether mitochondrial dysfunction in strain TejJ114 was 361 specific to liver, we also examined a number of mitochondrial parameters in isolated 362 skeletal muscle from these same mice. No treatment or strain-specific differences in 363 mitochondrial OCR were observed ( Fig. 7A-E skeletal muscle were unaffected by treatment and strain (Figure S3D-F; Fig. 10A), as 373 was also the case in heart ( Fig. S3G-I; Fig. 10B). Discussion 375The phenotypic plasticity of the mitochondria is crucial to allow energetic

The recent extension of human lifespan has not been matched by equivalent improvements in late-life health due to the corresponding increase in ageingassociated comorbidities and obesity, conditions exacerbated by the widespread adoption of the high calorie Western diet (HCD). Chronic low-grade inflammation underpins ageing-induced ill-health and thus we have focused on ES-62, an immunomodulator secreted by the parasitic worm Acanthocheilonema viteae that we have previously shown to have potent anti-inflammatory properties, as a novel therapeutic strategy. ES-62 was tested in a mouse model of HCD-accelerated ageing and found to ameliorate pathophysiological, inflammatory and metabolic parameters, when administered at only 1 µg/week. Strikingly, ES-62 also substantially increased the median survival of male HCD-mice. This extension was not observed with female mice and indeed, ES-62 treatment resulted in distinct gender-specific healthspan signatures. Combined with a machine learning approach, such signatures signpost candidate parameters key to promoting both healthspan and lifespan.Adoption of the modern Western diet (high fat and high sugar) has significantly contributed to a global pandemic in metabolic syndrome, obesity, type-2 diabetes and cardiovascular disease; ageing-associated conditions that impact on both wellbeing (healthspan) and lifespan 1,2 . This increasing major public health problem reflects, at least in part, that such a high calorie diet (HCD) disrupts the gut microbiome, with the consequent intestinal inflammation and loss of barrier integrity driving chronic systemic inflammation that appears to dysregulate immunometabolic pathways, accelerating the ageing process and reducing lifespan 1,3-7 . Interestingly, epidemiological data suggest that Western diet-associated diseases are rising fastest in in the developing world 2,8 , regions where parasitic worms (helminths) and other infectious agents are being eradicated 9 . Helminths promote their survival by releasing excretory-secretory (ES) products that, by dampening inflammation and promoting tissue repair, act to prevent worm expulsion but also limit host pathology 10 . Thus, the relatively rapid eradication of these parasites appears to have resulted in hyper-active host immune systems, characterised by chronic low-grade inflammation that may (further) contribute to development of obesity and associated metabolic syndrome co-morbidities, as well as allergic and autoimmune inflammatory disorders, in developing and urbanised countries 10 . Whilst this has questioned the wisdom of current mass parasite eradication programs, it has emphasised the potential of utilising worm infections or ES to treat a wide range of noncommunicable diseases that are characterised by chronic inflammation [11][12][13] . Indeed, we have shown that a single, defined ES protein, ES-62, can suppress pathology in mouse models of allergic and autoimmune inflammatory diseases 9,10,14-16 . ES-62 achieves this by virtue of immunomodulatory phosphorylcholine groups attached...