Effective discovery of causal disease genes must overcome the statistical challenges of quantitative genetics studies and the practical limitations of human biology experiments. Here we developed ...diseaseQUEST, an integrative approach that combines data from human genome-wide disease studies with in silico network models of tissue- and cell-type-specific function in model organisms to prioritize candidates within functionally conserved processes and pathways. We used diseaseQUEST to predict candidate genes for 25 different diseases and traits, including cancer, longevity, and neurodegenerative diseases. Focusing on Parkinson's disease (PD), a diseaseQUEST-directed Caenhorhabditis elegans behavioral screen identified several candidate genes, which we experimentally verified and found to be associated with age-dependent motility defects mirroring PD clinical symptoms. Furthermore, knockdown of the top candidate gene, bcat-1, encoding a branched chain amino acid transferase, caused spasm-like 'curling' and neurodegeneration in C. elegans, paralleling decreased BCAT1 expression in PD patient brains. diseaseQUEST is modular and generalizable to other model organisms and human diseases of interest.
The nematode Caenorhabditis elegans (C. elegans) is an excellent model to study reproductive aging because of its short life span, its cessation of reproduction in mid-adulthood, and the strong ...conservation of pathways that regulate longevity. During its lifetime, a wild-type C. elegans hermaphrodite usually lays about 200-300 self-fertilized hatchable eggs, which mainly occurs in the first three to five days of adulthood. Here, we report the development of a microfluidic assay and a real-time, automatic progeny counting system that records progeny counting information from many individual C. elegans hermaphrodites. This system offers many advantages compared to conventional plate assays. The flow of non-proliferating bacteria not only feeds the worms but also flushes the just-hatched young progeny through a filter that separates mothers from their offspring. The progeny that are flushed out of the chamber are detected and recorded using a novel algorithm. In our current design, one device contains as many as 16 individual chambers. Here we show examples of real-time progeny production information from wild-type (N2) and daf-2 (insulin receptor) mutants. We believe that this system has the potential to become a powerful, high time-resolution tool to study the detailed reproduction of C. elegans.
A decline in female reproduction is one of the earliest hallmarks of aging in many animals, including invertebrates and mammals 1–4. The insulin/insulin-like growth factor-1 signaling (IIS) pathway ...has a conserved role in regulating longevity 5 and also controls reproductive aging 2, 6. Although IIS transcriptional targets that regulate somatic aging have been characterized 7, 8, it was not known whether the same mechanisms influence reproductive aging. We previously showed that Caenorhabditis elegans daf-2 IIS receptor mutants extend reproductive span by maintaining oocyte quality with age 6, but IIS targets in oocytes had not been identified. Here, we compared the transcriptomes of aged daf-2(−) and wild-type oocytes, and distinguished IIS targets in oocytes from soma-specific targets. Remarkably, IIS appears to regulate reproductive and somatic aging through largely distinct mechanisms, although the binding motif for longevity factor PQM-1 8 was also overrepresented in oocyte targets. Reduction of oocyte-specific IIS targets decreased reproductive span extension and oocyte viability of daf-2(−) worms, and pqm-1 is required for daf-2(−)’s long reproductive span. Cathepsin-B-like gene expression and activity levels were reduced in aged daf-2(−) oocytes, and RNAi against cathepsin-B-like W07B8.4 improved oocyte quality maintenance and extended reproductive span. Importantly, adult-only pharmacological inhibition of cathepsin B proteases reduced age-dependent deterioration in oocyte quality, even when treatment was initiated in mid-reproduction. This suggests that it is possible to pharmacologically slow age-related reproductive decline through mid-life intervention. Oocyte-specific IIS target genes thereby revealed potential therapeutic targets for maintaining reproductive health with age.
•IIS targets in C. elegans oocytes differ from somatic targets•PQM-1 and oocyte IIS targets contribute to IIS’s regulation of reproductive aging•Cathepsin-B-like gene expression and protease activity reduced in daf-2(−) oocytes•Inhibiting cathepsin B in “reproductively aged” adults improves oocyte quality
Templeman, Luo, et al. provide evidence that insulin/IGF-1 signaling regulates reproductive and somatic aging through largely distinct mechanisms. Moreover, their transcriptomic approach indicates that cathepsin-B-like proteases negatively regulate oocyte quality with age, identifying a target to potentially slow age-related reproductive decline.
Cilia and extracellular vesicles (EVs) are signaling organelles 1. Cilia act as cellular sensory antennae, with defects resulting in human ciliopathies. Cilia both release and bind to EVs 1. EVs are ...sub-micron-sized particles released by cells and function in both short- and long-range intercellular communication. In C. elegans and mammals, the autosomal dominant polycystic kidney disease (ADPKD) gene products polycystin-1 and polycystin-2 localize to both cilia and EVs, act in the same genetic pathway, and function in a sensory capacity, suggesting ancient conservation 2. A fundamental understanding of EV biology and the relationship between the polycystins, cilia, and EVs is lacking. To define properties of a ciliated EV-releasing cell, we performed RNA-seq on 27 GFP-labeled EV-releasing neurons (EVNs) isolated from adult C. elegans. We identified 335 significantly overrepresented genes, of which 61 were validated by GFP reporters. The EVN transcriptional profile uncovered new pathways controlling EV biogenesis and polycystin signaling and also identified EV cargo, which included an antimicrobial peptide and ASIC channel. Tumor-necrosis-associated factor (TRAF) homologs trf-1 and trf-2 and the p38 mitogen-activated protein kinase (MAPK) pmk-1 acted in polycystin-signaling pathways controlling male mating behaviors. pmk-1 was also required for EV biogenesis, independent of the innate immunity MAPK signaling cascade. This first high-resolution transcriptome profile of a subtype of ciliated sensory neurons isolated from adult animals reveals the functional components of an EVN.
•Extracellular vesicle (EV)-releasing neuron (EVN) genes act in sensory signaling•This is the first cell-specific profile of EVNs isolated from adult C. elegans•TRAF homologs are required for polycystin-mediated male mating behaviors•p38 MAPK PMK-1 regulates EV biogenesis independent of its canonical kinase cascade
Cilia and extracellular vesicles (EVs) are physically associated from alga to man, suggesting ancient function. Wang et al. isolated and profiled ciliated EV-releasing neurons from adult C. elegans and identified 335 signature genes. These studies provide insight into the fundamental biology of EVs and the intimate relationship between EVs and cilia.
Understanding the molecular basis underlying aging is critical if we are to fully understand how and why we age—and possibly how to delay the aging process. Up until now, most longevity pathways were ...discovered in invertebrates because of their short lifespans and availability of genetic tools. Now, Reichwald et al. and Valenzano et al. independently provide a reference genome for the short-lived African turquoise killifish, establishing its role as a vertebrate system for aging research.
Understanding the molecular basis underlying aging is critical if we are to fully understand how and why we age—and possibly how to delay the aging process. Up until now, most longevity pathways were discovered in invertebrates because of their short lifespans and availability of genetic tools. Now, Reichwald et al. and Valenzano et al. independently provide a reference genome for the short-lived African turquoise killifish, establishing its role as a vertebrate system for aging research.
Aging is the greatest risk factor for a number of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease. Furthermore, normal aging is associated with a decline in sensory, motor, ...and cognitive functions. Emerging evidence suggests that synapse alterations, rather than neuronal cell death, are the causes of neuronal dysfunctions in normal aging and in early stages of neurodegenerative diseases. However, little is known about the mechanisms underlying age-related synaptic decline. Here, we uncover a surprising role of the anterograde molecular motor UNC-104/KIF1A as a key regulator of neural circuit deterioration in aging C. elegans. Through analyses of synapse protein localization, synaptic transmission, and animal behaviors, we find that reduced function of UNC-104 accelerates motor circuit dysfunction with age, whereas upregulation of UNC-104 significantly improves motor function at advanced ages and also mildly extends lifespan. In addition, UNC-104-overexpressing animals outperform wild-type controls in associative learning and memory tests. Further genetic analyses suggest that UNC-104 functions downstream of the DAF-2-signaling pathway and is regulated by the FOXO transcription factor DAF-16, which contributes to the effects of DAF-2 in neuronal aging. Together, our cellular, electrophysiological, and behavioral analyses highlight the importance of axonal transport in the maintenance of synaptic structural integrity and function during aging and raise the possibility of targeting kinesins to slow age-related neural circuit dysfunction.
•Aging neurons exhibit decreased activity of UNC-104/KIF1A, a neuronal kinesin•UNC-104 plays a critical role in synaptic and behavioral decline in aged worms•UNC-104 functions downstream of DAF-2 and is regulated by DAF-16
C. elegans exhibits an age-dependent decline of locomotion, learning, and memory. Li et al. demonstrate that decreased activity of UNC-104, a neuronal kinesin, plays a critical role in age-dependent degradation of neuronal functions. Overexpression of UNC-104 improves neural circuit functions in aged worms.
Female reproductive cessation is one of the earliest age-related declines humans experience, occurring in mid-adulthood. Similarly, Caenorhabditis elegans' reproductive span is short relative to its ...total life span, with reproduction ceasing about a third into its 15-20 day adulthood. All of the known mutations and treatments that extend C. elegans' reproductive period also regulate longevity, suggesting that reproductive span is normally linked to life span. C. elegans has two canonical TGF-beta signaling pathways. We recently found that the TGF-beta Dauer pathway regulates longevity through the Insulin/IGF-1 Signaling (IIS) pathway; here we show that this pathway has a moderate effect on reproductive span. By contrast, TGF-beta Sma/Mab signaling mutants exhibit a substantially extended reproductive period, more than doubling reproductive span in some cases. Sma/Mab mutations extend reproductive span disproportionately to life span and act independently of known regulators of somatic aging, such as Insulin/IGF-1 Signaling and Dietary Restriction. This is the first discovery of a pathway that regulates reproductive span independently of longevity and the first identification of the TGF-beta Sma/Mab pathway as a regulator of reproductive aging. Our results suggest that longevity and reproductive span regulation can be uncoupled, although they appear to normally be linked through regulatory pathways.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Loss of cognitive function with age is devastating. EGL-30/GNAQ and Gαq signaling pathways are highly conserved between C. elegans and mammals, and murine Gnaq is enriched in hippocampal neurons and ...declines with age. We found that activation of EGL-30 in aged worms triples memory span, and GNAQ gain of function significantly improved memory in aged mice: GNAQ(gf) in hippocampal neurons of 24-month-old mice (equivalent to 70- to 80-year-old humans) rescued age-related impairments in well-being and memory. Single-nucleus RNA sequencing revealed increased expression of genes regulating synaptic function, axon guidance, and memory in GNAQ-treated mice, and worm orthologs of these genes were required for long-term memory extension in worms. These experiments demonstrate that C. elegans is a powerful model to identify mammalian regulators of memory, leading to the identification of a pathway that improves memory in extremely old mice. To our knowledge, this is the oldest age at which an intervention has improved age-related cognitive decline.
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•EGL-30/GNAQ and Gαq signaling is highly conserved between worms and mammals•GNAQ gain of function in the hippocampus extends memory in 2-year-old mice•GNAQ gain of function also upregulates synaptic function, axon guidance, and memory genes•Worm orthologs of these genes are required for extended long-term memory
Stevenson et al. find that activation of GNAQ and Gαq signaling extends long-term memory in 2-year-old mice. GNAQ gain of function upregulates genes involved in plasticity, and worm orthologs were required for C. elegans memory. Invertebrates are a powerful model for identifying pathways that can improve memory in extremely old mammals.
Caenorhabditis elegans
is used as a model organism to study a wide range of topics in molecular and cellular biology. Conventional
C. elegans
assays often require a large sample size with frequent ...manipulations, rendering them labor-intensive. Automated high-throughput workflows may not be always the best solution to reduce benchwork labor, as they may introduce more complexity. Thus, most assays are carried out manually, where logging and digitizing experimental data can be as time-consuming as picking and scoring worms. Here we report the development of
Ce
Aid,
C. elegans
Application for inputting data, which significantly expedites the data entry process, utilizing swiping gestures and a voice recognition algorithm for logging data using a standard smartphone or Android device. This modular platform can also be adapted for a wide range of assays where recording data is laborious, even beyond worm research.
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