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Light and pheromone-sensing neurons regulates cold habituation through insulin signalling in Caenorhabditis elegans.

Ohta A, Ujisawa T, Sonoda S, Kuhara A - Nat Commun (2014)

Bottom Line: However, how animals habituate to temperature is poorly understood.Calcium imaging reveals that ASJ neurons respond to temperature.Thus, temperature sensation in a light and pheromone-sensing neuron produces a robust effect on insulin signalling that controls experience-dependent temperature habituation.

View Article: PubMed Central - PubMed

Affiliation: 1] Laboratory of Molecular and Cellular Regulation, Faculty of Science and Engineering, Institute for Integrative Neurobiology, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan [2].

ABSTRACT
Temperature is a critical environmental stimulus that has a strong impact on an organism's biochemistry. Animals can respond to changes in ambient temperature through behaviour or altered physiology. However, how animals habituate to temperature is poorly understood. The nematode C. elegans stores temperature experiences and can induce temperature habituation-linked cold tolerance. Here we show that light and pheromone-sensing neurons (ASJ) regulate cold habituation through insulin signalling. Calcium imaging reveals that ASJ neurons respond to temperature. Cold habituation is abnormal in a mutant with impaired cGMP signalling in ASJ neurons. Insulin released from ASJ neurons is received by the intestine and neurons regulating gene expression for cold habituation. Thus, temperature sensation in a light and pheromone-sensing neuron produces a robust effect on insulin signalling that controls experience-dependent temperature habituation.

No MeSH data available.


Related in: MedlinePlus

Insulin signalling regulates gene expression during cold tolerance.(a) Temperature experience-dependent cold tolerance of mutants defective in insulin signalling, TGF-β signalling or steroid hormone signalling. Mutants defective in insulin signalling showed abnormal cold tolerance after 20 °C cultivation. In contrast, mutants of TGF-β signalling and steroid hormone signalling showed normal cold tolerance. For each assay, n≥6. (b) Tissue-specific rescue experiments of daf-2  mutants. For each assay, n≥9. Tissue-specific promoters used in this experiment were the unc-54 promoter (body wall muscle), unc-14 promoter (all neurons) and ges-1 promoter (intestine). ges-1p::daf-2cDNA and unc-14p::daf-2cDNA were co-injected to allow co-expression in both the intestine and neurons. Abnormalities in 25 °C-cultivated daf-2 animals were rescued by daf-2 cDNA co-expressed in both the intestine and neurons. For each assay, n≥9. (c) Cold tolerance in the cold receptor TRP channel and downstream signalling mutant33. PKC-2 is a downstream molecule of cold receptor/TRPA-1 that functions in the intestine. pkc-2 and trpa-1 mutants did not show abnormal defects in cold tolerance. The trpa-1 mutation did not affect cold tolerance in the daf-2; trpa-1 double mutant. daf-2; trpa-1, wild type; XuEx601 and daf-2(e1370); XuEx601 strains were kindly provided by Dr Xu33. Overexpression of TRPA-1 also did not affect cold tolerance in both the wild type and daf-2(e1370) mutant. For each assay, n≥9. Animals with the daf-2(e1370) mutation were cultivated at 15 °C from egg to L4 larvae, and after that, animals were cultivated at 20 or 25 °C overnight from L4 to adult because of the daf-c phenotype (b,c). Error bars indicate standard error of the mean. Analysis of variance followed by Dunnet post-hoc test was used for multiple comparisons. **P<0.01.
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f6: Insulin signalling regulates gene expression during cold tolerance.(a) Temperature experience-dependent cold tolerance of mutants defective in insulin signalling, TGF-β signalling or steroid hormone signalling. Mutants defective in insulin signalling showed abnormal cold tolerance after 20 °C cultivation. In contrast, mutants of TGF-β signalling and steroid hormone signalling showed normal cold tolerance. For each assay, n≥6. (b) Tissue-specific rescue experiments of daf-2 mutants. For each assay, n≥9. Tissue-specific promoters used in this experiment were the unc-54 promoter (body wall muscle), unc-14 promoter (all neurons) and ges-1 promoter (intestine). ges-1p::daf-2cDNA and unc-14p::daf-2cDNA were co-injected to allow co-expression in both the intestine and neurons. Abnormalities in 25 °C-cultivated daf-2 animals were rescued by daf-2 cDNA co-expressed in both the intestine and neurons. For each assay, n≥9. (c) Cold tolerance in the cold receptor TRP channel and downstream signalling mutant33. PKC-2 is a downstream molecule of cold receptor/TRPA-1 that functions in the intestine. pkc-2 and trpa-1 mutants did not show abnormal defects in cold tolerance. The trpa-1 mutation did not affect cold tolerance in the daf-2; trpa-1 double mutant. daf-2; trpa-1, wild type; XuEx601 and daf-2(e1370); XuEx601 strains were kindly provided by Dr Xu33. Overexpression of TRPA-1 also did not affect cold tolerance in both the wild type and daf-2(e1370) mutant. For each assay, n≥9. Animals with the daf-2(e1370) mutation were cultivated at 15 °C from egg to L4 larvae, and after that, animals were cultivated at 20 or 25 °C overnight from L4 to adult because of the daf-c phenotype (b,c). Error bars indicate standard error of the mean. Analysis of variance followed by Dunnet post-hoc test was used for multiple comparisons. **P<0.01.

Mentions: To determine the molecules downstream of insulin in temperature experience-dependent cold tolerance, we tested various mutants defective in the known insulin-signalling pathway (Figs 5b,c and 6a). Phenotypic analysis showed that mutants defective in the DAF-2/insulin receptor or its downstream molecules showed abnormal enhancement of cold tolerance (Figs 5c and 6a; Supplementary Fig. 4c)28. These results are consistent with a previous report showing that AGE-1/PI3 kinase and DAF-16/FOXO are involved in cold tolerance2. DAF-2 is the only insulin receptor in C. elegans, while there are about 40 ligands for insulin receptors. Genetic epistasis analysis revealed that two insulins, DAF-28 and INS-6, are both positive agonists that work redundantly on the DAF-2/insulin receptor in cold tolerance, because an ins-6; daf-28 double mutant showed a stronger phenotype than each single mutant (Fig. 5c)2529. Additional genetic epistasis analysis indicated that INS-1/insulin genetically inhibits the DAF-2/insulin receptor through a negative regulation of INS-6/insulin (Fig. 5c, Supplementary Fig. 4c)2630. Abnormal increments of cold tolerance in daf-2 mutants were suppressed by mutation in the DAF-16/FOXO-type transcriptional factor (Fig. 5c). We found that daf-16 mutant animals showed reduced cold tolerance after cultivation at 18 °C (Supplementary Fig. 4b), although daf-16 mutant animals did not show decreased cold tolerance after cultivation at 20 or 15 °C (Fig. 5c; Supplementary Fig. 4a). In contrast, overexpression of the daf-16 gene induced abnormal increments of cold tolerance (Fig. 5c (wild type; Is[daf-16])). These results suggest that DAF-2/insulin receptor signalling and DAF-16/FOXO act as negative and positive regulators for cold tolerance, respectively. Because 15 °C-cultivated mutant animals defective in insulin signalling appeared to be cold tolerant (Supplementary Fig. 4a), it is probable that additional signalling pathways exist that lead to cold tolerance.


Light and pheromone-sensing neurons regulates cold habituation through insulin signalling in Caenorhabditis elegans.

Ohta A, Ujisawa T, Sonoda S, Kuhara A - Nat Commun (2014)

Insulin signalling regulates gene expression during cold tolerance.(a) Temperature experience-dependent cold tolerance of mutants defective in insulin signalling, TGF-β signalling or steroid hormone signalling. Mutants defective in insulin signalling showed abnormal cold tolerance after 20 °C cultivation. In contrast, mutants of TGF-β signalling and steroid hormone signalling showed normal cold tolerance. For each assay, n≥6. (b) Tissue-specific rescue experiments of daf-2  mutants. For each assay, n≥9. Tissue-specific promoters used in this experiment were the unc-54 promoter (body wall muscle), unc-14 promoter (all neurons) and ges-1 promoter (intestine). ges-1p::daf-2cDNA and unc-14p::daf-2cDNA were co-injected to allow co-expression in both the intestine and neurons. Abnormalities in 25 °C-cultivated daf-2 animals were rescued by daf-2 cDNA co-expressed in both the intestine and neurons. For each assay, n≥9. (c) Cold tolerance in the cold receptor TRP channel and downstream signalling mutant33. PKC-2 is a downstream molecule of cold receptor/TRPA-1 that functions in the intestine. pkc-2 and trpa-1 mutants did not show abnormal defects in cold tolerance. The trpa-1 mutation did not affect cold tolerance in the daf-2; trpa-1 double mutant. daf-2; trpa-1, wild type; XuEx601 and daf-2(e1370); XuEx601 strains were kindly provided by Dr Xu33. Overexpression of TRPA-1 also did not affect cold tolerance in both the wild type and daf-2(e1370) mutant. For each assay, n≥9. Animals with the daf-2(e1370) mutation were cultivated at 15 °C from egg to L4 larvae, and after that, animals were cultivated at 20 or 25 °C overnight from L4 to adult because of the daf-c phenotype (b,c). Error bars indicate standard error of the mean. Analysis of variance followed by Dunnet post-hoc test was used for multiple comparisons. **P<0.01.
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f6: Insulin signalling regulates gene expression during cold tolerance.(a) Temperature experience-dependent cold tolerance of mutants defective in insulin signalling, TGF-β signalling or steroid hormone signalling. Mutants defective in insulin signalling showed abnormal cold tolerance after 20 °C cultivation. In contrast, mutants of TGF-β signalling and steroid hormone signalling showed normal cold tolerance. For each assay, n≥6. (b) Tissue-specific rescue experiments of daf-2 mutants. For each assay, n≥9. Tissue-specific promoters used in this experiment were the unc-54 promoter (body wall muscle), unc-14 promoter (all neurons) and ges-1 promoter (intestine). ges-1p::daf-2cDNA and unc-14p::daf-2cDNA were co-injected to allow co-expression in both the intestine and neurons. Abnormalities in 25 °C-cultivated daf-2 animals were rescued by daf-2 cDNA co-expressed in both the intestine and neurons. For each assay, n≥9. (c) Cold tolerance in the cold receptor TRP channel and downstream signalling mutant33. PKC-2 is a downstream molecule of cold receptor/TRPA-1 that functions in the intestine. pkc-2 and trpa-1 mutants did not show abnormal defects in cold tolerance. The trpa-1 mutation did not affect cold tolerance in the daf-2; trpa-1 double mutant. daf-2; trpa-1, wild type; XuEx601 and daf-2(e1370); XuEx601 strains were kindly provided by Dr Xu33. Overexpression of TRPA-1 also did not affect cold tolerance in both the wild type and daf-2(e1370) mutant. For each assay, n≥9. Animals with the daf-2(e1370) mutation were cultivated at 15 °C from egg to L4 larvae, and after that, animals were cultivated at 20 or 25 °C overnight from L4 to adult because of the daf-c phenotype (b,c). Error bars indicate standard error of the mean. Analysis of variance followed by Dunnet post-hoc test was used for multiple comparisons. **P<0.01.
Mentions: To determine the molecules downstream of insulin in temperature experience-dependent cold tolerance, we tested various mutants defective in the known insulin-signalling pathway (Figs 5b,c and 6a). Phenotypic analysis showed that mutants defective in the DAF-2/insulin receptor or its downstream molecules showed abnormal enhancement of cold tolerance (Figs 5c and 6a; Supplementary Fig. 4c)28. These results are consistent with a previous report showing that AGE-1/PI3 kinase and DAF-16/FOXO are involved in cold tolerance2. DAF-2 is the only insulin receptor in C. elegans, while there are about 40 ligands for insulin receptors. Genetic epistasis analysis revealed that two insulins, DAF-28 and INS-6, are both positive agonists that work redundantly on the DAF-2/insulin receptor in cold tolerance, because an ins-6; daf-28 double mutant showed a stronger phenotype than each single mutant (Fig. 5c)2529. Additional genetic epistasis analysis indicated that INS-1/insulin genetically inhibits the DAF-2/insulin receptor through a negative regulation of INS-6/insulin (Fig. 5c, Supplementary Fig. 4c)2630. Abnormal increments of cold tolerance in daf-2 mutants were suppressed by mutation in the DAF-16/FOXO-type transcriptional factor (Fig. 5c). We found that daf-16 mutant animals showed reduced cold tolerance after cultivation at 18 °C (Supplementary Fig. 4b), although daf-16 mutant animals did not show decreased cold tolerance after cultivation at 20 or 15 °C (Fig. 5c; Supplementary Fig. 4a). In contrast, overexpression of the daf-16 gene induced abnormal increments of cold tolerance (Fig. 5c (wild type; Is[daf-16])). These results suggest that DAF-2/insulin receptor signalling and DAF-16/FOXO act as negative and positive regulators for cold tolerance, respectively. Because 15 °C-cultivated mutant animals defective in insulin signalling appeared to be cold tolerant (Supplementary Fig. 4a), it is probable that additional signalling pathways exist that lead to cold tolerance.

Bottom Line: However, how animals habituate to temperature is poorly understood.Calcium imaging reveals that ASJ neurons respond to temperature.Thus, temperature sensation in a light and pheromone-sensing neuron produces a robust effect on insulin signalling that controls experience-dependent temperature habituation.

View Article: PubMed Central - PubMed

Affiliation: 1] Laboratory of Molecular and Cellular Regulation, Faculty of Science and Engineering, Institute for Integrative Neurobiology, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan [2].

ABSTRACT
Temperature is a critical environmental stimulus that has a strong impact on an organism's biochemistry. Animals can respond to changes in ambient temperature through behaviour or altered physiology. However, how animals habituate to temperature is poorly understood. The nematode C. elegans stores temperature experiences and can induce temperature habituation-linked cold tolerance. Here we show that light and pheromone-sensing neurons (ASJ) regulate cold habituation through insulin signalling. Calcium imaging reveals that ASJ neurons respond to temperature. Cold habituation is abnormal in a mutant with impaired cGMP signalling in ASJ neurons. Insulin released from ASJ neurons is received by the intestine and neurons regulating gene expression for cold habituation. Thus, temperature sensation in a light and pheromone-sensing neuron produces a robust effect on insulin signalling that controls experience-dependent temperature habituation.

No MeSH data available.


Related in: MedlinePlus