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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

Presence of the germline alters miRNA abundance(A-F) Normalized Ct values demonstrating that miRNA expression from the mir-35-41 cluster is dramatically different in N2 animals with age but is virtually absent, at all ages examined, in glp-1 germline-less animals. In N2 animals, mir-35 (A), mir-36 (B) and mir-37 (C) are expressed at much higher levels in old animals, while mir-38 (D) has a median value that is higher in aged animals. mir-39 (E) is also dramatically higher in aged animals. In glp-1 mutants only mir-37 (F) was detected, and its levels were much lower than in wild type animals. (G) Graphical representation of the difference between miRNA abundance in old and young worms, for both wild type and germline-less mutants. The values graphed are the average values at the old age minus the averaged values at the young age for each of the two genotypes with log2 transformation to describe the fold change (i.e. 2^-(average Ct old - average Ct young)). 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 2: Presence of the germline alters miRNA abundance(A-F) Normalized Ct values demonstrating that miRNA expression from the mir-35-41 cluster is dramatically different in N2 animals with age but is virtually absent, at all ages examined, in glp-1 germline-less animals. In N2 animals, mir-35 (A), mir-36 (B) and mir-37 (C) are expressed at much higher levels in old animals, while mir-38 (D) has a median value that is higher in aged animals. mir-39 (E) is also dramatically higher in aged animals. In glp-1 mutants only mir-37 (F) was detected, and its levels were much lower than in wild type animals. (G) Graphical representation of the difference between miRNA abundance in old and young worms, for both wild type and germline-less mutants. The values graphed are the average values at the old age minus the averaged values at the young age for each of the two genotypes with log2 transformation to describe the fold change (i.e. 2^-(average Ct old - average Ct young)). 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: Analysis of the expression profiles in single worms lead to the identification of miRNAs which had significantly altered levels between young and old animals (Figure 1 and Table 1). Some miRNAs that showed altered levels with age had higher levels later in life. Of these, the most statistically significant increases were observed for miRNAs; mir-51, mir-44, mir-240 and the members of the mir-35-41 cluster (Figure 1B-D and Figure 2A-E). We also identified miRNAs whose levels decreased significantly with age; among these mir-235, mir-60 andmir-58 were identified as those being consistently detected and showing the most significant decrease with age (Figure 1E-G). Other than the mir-35 family members all of these miRNAs showed an increase in variation with age (Supplemental Table 1). To test these results with an independent approach we quantified green fluorescent protein (GFP) expression in aged worm strains carrying promoter-GFP fusions for the age dependent hits mir-1 (Supplemental Figure 1), mir-60 (Supplemental Figure 2) and mir-228 (Supplemental Figure 3). In agreement with our biochemical results, these strains showed decreased expression of GFP with age.


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)

Presence of the germline alters miRNA abundance(A-F) Normalized Ct values demonstrating that miRNA expression from the mir-35-41 cluster is dramatically different in N2 animals with age but is virtually absent, at all ages examined, in glp-1 germline-less animals. In N2 animals, mir-35 (A), mir-36 (B) and mir-37 (C) are expressed at much higher levels in old animals, while mir-38 (D) has a median value that is higher in aged animals. mir-39 (E) is also dramatically higher in aged animals. In glp-1 mutants only mir-37 (F) was detected, and its levels were much lower than in wild type animals. (G) Graphical representation of the difference between miRNA abundance in old and young worms, for both wild type and germline-less mutants. The values graphed are the average values at the old age minus the averaged values at the young age for each of the two genotypes with log2 transformation to describe the fold change (i.e. 2^-(average Ct old - average Ct young)). 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 2: Presence of the germline alters miRNA abundance(A-F) Normalized Ct values demonstrating that miRNA expression from the mir-35-41 cluster is dramatically different in N2 animals with age but is virtually absent, at all ages examined, in glp-1 germline-less animals. In N2 animals, mir-35 (A), mir-36 (B) and mir-37 (C) are expressed at much higher levels in old animals, while mir-38 (D) has a median value that is higher in aged animals. mir-39 (E) is also dramatically higher in aged animals. In glp-1 mutants only mir-37 (F) was detected, and its levels were much lower than in wild type animals. (G) Graphical representation of the difference between miRNA abundance in old and young worms, for both wild type and germline-less mutants. The values graphed are the average values at the old age minus the averaged values at the young age for each of the two genotypes with log2 transformation to describe the fold change (i.e. 2^-(average Ct old - average Ct young)). 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: Analysis of the expression profiles in single worms lead to the identification of miRNAs which had significantly altered levels between young and old animals (Figure 1 and Table 1). Some miRNAs that showed altered levels with age had higher levels later in life. Of these, the most statistically significant increases were observed for miRNAs; mir-51, mir-44, mir-240 and the members of the mir-35-41 cluster (Figure 1B-D and Figure 2A-E). We also identified miRNAs whose levels decreased significantly with age; among these mir-235, mir-60 andmir-58 were identified as those being consistently detected and showing the most significant decrease with age (Figure 1E-G). Other than the mir-35 family members all of these miRNAs showed an increase in variation with age (Supplemental Table 1). To test these results with an independent approach we quantified green fluorescent protein (GFP) expression in aged worm strains carrying promoter-GFP fusions for the age dependent hits mir-1 (Supplemental Figure 1), mir-60 (Supplemental Figure 2) and mir-228 (Supplemental Figure 3). In agreement with our biochemical results, these strains showed decreased expression of GFP with age.

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