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Age-related micro-RNA abundance in individual C. elegans.

Lucanic M, Graham J, Scott G, Bhaumik D, Benz CC, Hubbard A, Lithgow GJ, Melov S - Aging (Albany NY) (2013)

Bottom Line: To identify expression differences associated with either reproductive or somatic tissues, we analyzed wild type and mutants that lacked germlines. miRNAs from the mir-35-41 cluster increased in abundance with age in wild type animals, but were nearly absent from mutants lacking a germline, suggesting their age-related increase originates from the germline.Most miRNAs with age-dependent levels did not have a major effect on lifespan, as corresponding deletion mutants exhibited wild-type lifespans.Our genetic characterization indicates that mir-71 acts at least partly in parallel to insulin/IGF like signals to influence lifespan.

View Article: PubMed Central - PubMed

Affiliation: Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA. mlucanic@buckinstitute.org

ABSTRACT
Non-coding small RNAs of the micro-RNA class (miRNA) are conserved regulators of gene function with a broad impact on biological processes. We screened miRNA levels for age-related changes in individual worms and investigated their influence on the lifespan of the nematode C. elegans. We measured the abundance of 69 miRNAs expressed in individual animals at different ages with over thirty five thousand discrete quantitative nano-fluidic polymerase chain reactions. We found that miRNA abundance was highly variable between individual worms raised under identical conditions and that expression variability generally increased with age. To identify expression differences associated with either reproductive or somatic tissues, we analyzed wild type and mutants that lacked germlines. miRNAs from the mir-35-41 cluster increased in abundance with age in wild type animals, but were nearly absent from mutants lacking a germline, suggesting their age-related increase originates from the germline. Most miRNAs with age-dependent levels did not have a major effect on lifespan, as corresponding deletion mutants exhibited wild-type lifespans. The major exception to this was mir-71, which increased in abundance with age and was required for normal longevity. Our genetic characterization indicates that mir-71 acts at least partly in parallel to insulin/IGF like signals to influence lifespan.

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Related in: MedlinePlus

Dynamic changes of miRNAs with age in long-lived germline ablated animals(A) Survivorship of a population of N2 (wild type) animals, from which individuals were harvested for analysis at Day 1, Day 6, Day 12 and Day 18 of adulthood. (B-G) miRNA levels in individual worms (columns) at four time points are shown for mir-54 (B), mir-67 (C), mir-354 (D), mir-53 (E), mir-64 (F), and mir-81 (G). (H) Graphical representation of the fold change in miRNA abundance between young and old animals using averaged values. In all graphs with error bars they indicate the standard error of the mean. In individual worm graphs, each point is the average from 2-3 technical replicates.
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Figure 3: Dynamic changes of miRNAs with age in long-lived germline ablated animals(A) Survivorship of a population of N2 (wild type) animals, from which individuals were harvested for analysis at Day 1, Day 6, Day 12 and Day 18 of adulthood. (B-G) miRNA levels in individual worms (columns) at four time points are shown for mir-54 (B), mir-67 (C), mir-354 (D), mir-53 (E), mir-64 (F), and mir-81 (G). (H) Graphical representation of the fold change in miRNA abundance between young and old animals using averaged values. In all graphs with error bars they indicate the standard error of the mean. In individual worm graphs, each point is the average from 2-3 technical replicates.

Mentions: To test the contribution of the germline on miRNA expression we performed qPCR analysis of miRNA levels, on germline-less animals. We chose a mutant strain that allowed for genetic ablation of the germline during development. glp-1(e2141) mutants are temperature sensitive sterile and at the restrictive temperature lack a germline due to the inability of the germline stem cells to remain mitotically active. These animals are also long-lived in a DAF-16 and DAF-12 dependent manner [37], however they still respond to deficits in insulin/IGF like signaling with lifespan extension. To examine changes with age in animals lacking a germline, we collected individual glp-1 mutants spanning 4 adult ages that included both young and old animals (Figure 3A). Interestingly we found that expression from the mir-35-41 gene cluster was nearly absent in animals that lacked a gonad. Of the mir-35-41 cluster we only detected mir-37 in the germline ablated animals, but only in 30% of the individual worm samples. The levels of mir-37 we measured were much lower than those observed in wild type young adult animals (Figure 2F and compare Supplemental Tables 1 and 2). These results along with previous reports, suggests that the age-dependent increase in the mir-35 group arises from high expression in the germline of post-reproductive animals.


Age-related micro-RNA abundance in individual C. elegans.

Lucanic M, Graham J, Scott G, Bhaumik D, Benz CC, Hubbard A, Lithgow GJ, Melov S - Aging (Albany NY) (2013)

Dynamic changes of miRNAs with age in long-lived germline ablated animals(A) Survivorship of a population of N2 (wild type) animals, from which individuals were harvested for analysis at Day 1, Day 6, Day 12 and Day 18 of adulthood. (B-G) miRNA levels in individual worms (columns) at four time points are shown for mir-54 (B), mir-67 (C), mir-354 (D), mir-53 (E), mir-64 (F), and mir-81 (G). (H) Graphical representation of the fold change in miRNA abundance between young and old animals using averaged values. In all graphs with error bars they indicate the standard error of the mean. In individual worm graphs, each point is the average from 2-3 technical replicates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824409&req=5

Figure 3: Dynamic changes of miRNAs with age in long-lived germline ablated animals(A) Survivorship of a population of N2 (wild type) animals, from which individuals were harvested for analysis at Day 1, Day 6, Day 12 and Day 18 of adulthood. (B-G) miRNA levels in individual worms (columns) at four time points are shown for mir-54 (B), mir-67 (C), mir-354 (D), mir-53 (E), mir-64 (F), and mir-81 (G). (H) Graphical representation of the fold change in miRNA abundance between young and old animals using averaged values. In all graphs with error bars they indicate the standard error of the mean. In individual worm graphs, each point is the average from 2-3 technical replicates.
Mentions: To test the contribution of the germline on miRNA expression we performed qPCR analysis of miRNA levels, on germline-less animals. We chose a mutant strain that allowed for genetic ablation of the germline during development. glp-1(e2141) mutants are temperature sensitive sterile and at the restrictive temperature lack a germline due to the inability of the germline stem cells to remain mitotically active. These animals are also long-lived in a DAF-16 and DAF-12 dependent manner [37], however they still respond to deficits in insulin/IGF like signaling with lifespan extension. To examine changes with age in animals lacking a germline, we collected individual glp-1 mutants spanning 4 adult ages that included both young and old animals (Figure 3A). Interestingly we found that expression from the mir-35-41 gene cluster was nearly absent in animals that lacked a gonad. Of the mir-35-41 cluster we only detected mir-37 in the germline ablated animals, but only in 30% of the individual worm samples. The levels of mir-37 we measured were much lower than those observed in wild type young adult animals (Figure 2F and compare Supplemental Tables 1 and 2). These results along with previous reports, suggests that the age-dependent increase in the mir-35 group arises from high expression in the germline of post-reproductive animals.

Bottom Line: To identify expression differences associated with either reproductive or somatic tissues, we analyzed wild type and mutants that lacked germlines. miRNAs from the mir-35-41 cluster increased in abundance with age in wild type animals, but were nearly absent from mutants lacking a germline, suggesting their age-related increase originates from the germline.Most miRNAs with age-dependent levels did not have a major effect on lifespan, as corresponding deletion mutants exhibited wild-type lifespans.Our genetic characterization indicates that mir-71 acts at least partly in parallel to insulin/IGF like signals to influence lifespan.

View Article: PubMed Central - PubMed

Affiliation: Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA. mlucanic@buckinstitute.org

ABSTRACT
Non-coding small RNAs of the micro-RNA class (miRNA) are conserved regulators of gene function with a broad impact on biological processes. We screened miRNA levels for age-related changes in individual worms and investigated their influence on the lifespan of the nematode C. elegans. We measured the abundance of 69 miRNAs expressed in individual animals at different ages with over thirty five thousand discrete quantitative nano-fluidic polymerase chain reactions. We found that miRNA abundance was highly variable between individual worms raised under identical conditions and that expression variability generally increased with age. To identify expression differences associated with either reproductive or somatic tissues, we analyzed wild type and mutants that lacked germlines. miRNAs from the mir-35-41 cluster increased in abundance with age in wild type animals, but were nearly absent from mutants lacking a germline, suggesting their age-related increase originates from the germline. Most miRNAs with age-dependent levels did not have a major effect on lifespan, as corresponding deletion mutants exhibited wild-type lifespans. The major exception to this was mir-71, which increased in abundance with age and was required for normal longevity. Our genetic characterization indicates that mir-71 acts at least partly in parallel to insulin/IGF like signals to influence lifespan.

Show MeSH
Related in: MedlinePlus