Drosophila HCN mediates gustatory homeostasis by preserving sensillar transepithelial potential in sweet environments
- Neurovascular Unit Research Group, Korea Brain Research Institute, Republic of Korea
- Department of Anatomy and Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Samsung Medical Center, Republic of Korea
- Department of Biological Sciences, Sungkyunkwan University, Republic of Korea
- Department of Brain Sciences, DGIST, Republic of Korea
Figures
Figure 1 with 2 supplements
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel is necessary for the normal activity of bitter-sensing GRNs (bGRNs), although expressed in sweet-sensing GRNs (sGRNs).
Representative 5 s-long traces of sensillum recording with either caffeine or sucrose at the indicated concentrations, shown along with box plots of spiking frequencies. (A) Caffeine-evoked bitter …
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Figure 1—source data 1
Spiking frequencies from the first 5-sec bin following the contact with indicated tastants, which are for box plots in the Figure 1.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig1-data1-v1.xlsx
Figure 1—figure supplement 1
Ih is required for spiking responses to various bitter chemical compounds.
Representative 5 s-long traces of sensillum recording in wild-type (WT), Ihf03355 and a genomic rescue are shown along with box plots of spiking frequencies for indicated bitters, such as berberine …
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Figure 1—figure supplement 1—source data 1
The first 5-sec spiking frequencies in response to the indicated bitter compounds, which were used to draw the box plots.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig1-figsupp1-data1-v1.xlsx
Figure 1—figure supplement 2
Ih RNAi knockdown in adulthood reduces spiking frequencies in response to 2 mM caffeine but increases spiking frequencies to 50 mM sucrose.
(A) Schematic diagram depicting the design of temporal control of the RNAi. (B) Box plots of spiking frequencies obtained with indicated bitter and sweet chemical compounds at temperatures …
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Figure 1—figure supplement 2—source data 1
The first 5-sec firing frequencies in response to the indicated tastants in Figure 1—figure supplement 2B.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig1-figsupp2-data1-v1.xlsx
Figure 2
Sensillum potential (SP) is reduced in hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-deficient animals.
(A) Schematic diagram illustrating the sensillum potential in the taste bristle sensilla (Left). Black upward arrow indicates ion transport by pumps and transporters in support cells from the …
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Figure 2—source data 1
Acquired potential values in indicated experiments in Figure 2.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig2-data1-v1.xlsx
Figure 3 with 1 supplement
Inactivation of sweet-sensing GRNs (sGRNs) raises bitter-sensing gustatory receptor neurons (bGRN) activity and sensillum potential (SP), both of which are reversed by Ih deficiency.
(A) The bGRN spiking was increased in response to the indicated bitters in Gr64af mutants impaired in sucrose and glucose sensing. Ber: 0.5, Lob: 0.5, NMM: 2, Caf: 2 (i-type), and 0.09 (s-type), …
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Figure 3—source data 1
Spiking frequencies and sensillum potentials obtained in the experiments of Figure 3.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig3-data1-v1.xlsx
Figure 3—figure supplement 1
Water gustatory receptor neurons (GRNs) rely on the sensillum potential (SP) guarded by hyperpolarization-activated cyclic nucleotide-gated (HCN) channel in the L-type bristles.
(A) Water GRN activity evoked by 0.1 mM tricholine citrate (TCC) was appraised in wild-type (WT), Ihf03355 and a genomic rescue. The representative traces (Left) and box plots of spiking frequencies …
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Figure 3—figure supplement 1—source data 1
Water cell spiking frequencies and L-type bristle sensillum potential data.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig3-figsupp1-data1-v1.xlsx
Figure 4 with 1 supplement
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel suppresses HCN-expressing gustatory receptor neurons (GRNs) and increases sensillum potential (SP).
(A) HCN misexpressed in bitter-sensing gustatory receptor neurons (bGRNs) flattened the dose dependence to caffeine. (B) HCN ectopically expressed in bGRNs elevates sweet-sensing GRN (sGRN) …
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Figure 4—source data 1
Spiking frequencies and sensillum potential data from Figure 4.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig4-data1-v1.xlsx
Figure 4—figure supplement 1
Overexpression of Ih-RF in WT sGRNs suppresses their spiking responses to 50 mM sucrose in a delayed manner.
Post-stimulus spiking frequencies binned every second are shown for sucrose concentrations, 5, 10, and 50 mM (A, B and C, respectively). *: p<0.05, Tukey’s, Dunn’s or Games-Howell test, depending on …
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Figure 4—figure supplement 1—source data 1
Post-stimulus spiking frequenceis in 1-sec bins.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig4-figsupp1-data1-v1.xlsx
Figure 5 with 1 supplement
Sweetness in the diet decreases sensillum potential (SP), bitter-sensing gustatory receptor neuron (bGRN) activity, and bitter avoidance.
(A) Sweetness in the media reduced the 2 mM caffeine-evoked bGRN spiking, which was fully recovered in 4 hr incubation with sorbitol only food. Ihf03355 was affected by the type of the media more …
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Figure 5—source data 1
Electrophysiology data and avoidance indices.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig5-data1-v1.xlsx
Figure 5—figure supplement 1
Feeding avoidance to lobeline and theophylline is reduced in Ihf03355 following prior exposure to sweetness.
(A) Bitter avoidance was evaluated by capillary feeder assay (CAFE). (B, C) Ih is required for avoidance to indicated bitters for flies maintained on sweet cornmeal food (sweet exposure +: filled …
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Figure 5—figure supplement 1—source data 1
Avoidance indices obtained with indicated bitters.
- https://cdn.elifesciences.org/articles/96602/elife-96602-fig5-figsupp1-data1-v1.xlsx
Tables
Key resources table
| Reagent type (species) or resource | Designation | Source or reference | Identifiers | Additional information |
|---|---|---|---|---|
| Genetic reagent (Drosophila melanogaster) | Cantonized w1118 | NA | NA | NA |
| Genetic reagent (D. melanogaster) | Gr64af | Dr. Moon at Yonsei U. | NA | NA |
| Genetic reagent (D. melanogaster) | Ihf03355 | Bloomington Drosophila Stock Center | BDSC: 85660; Flybase: FBti0051182 | NA |
| Genetic reagent (D. melanogaster) | Mi{Trojan-GAL4.0}IhMI03196-TG4.0 (Ih-TG4.0) | Bloomington Drosophila Stock Center | BDSC: 76162; Flybase: FBti0187533 | NA |
| Genetic reagent (D. melanogaster) | Duplicate of Dp(2;3)GV-CH321-22I11 | Bloomington Drosophila Stock Center | BDSC: 89744; Flybase: FBab0048672 | NA |
| Genetic reagent (D. melanogaster) | Gr5a-Gal4 | Dr. Scott at UC Berkeley | NA | NA |
| Genetic reagent (D. melanogaster) | Gr64fLexA | Dr. Amrein at TAMU | NA | NA |
| Genetic reagent (D. melanogaster) | Gr64f-Gal4 | Dr. Amrein at TAMU | NA | NA |
| Genetic reagent (D. melanogaster) | Gr89a-Gal4 | Dr. Carlson at Yale | NA | NA |
| Genetic reagent (D. melanogaster) | Gr66a-Gal4 | Dr. Amrein at TAMU | NA | NA |
| Genetic reagent (D. melanogaster) | UAS-Kir2.1 | Bloomington Drosophila Stock Center | BDSC: 6595 | NA |
| Genetic reagent (D. melanogaster) | LexAop-Kir2.1 | Dr. Dickson at Janellia | NA | NA |
| Genetic reagent (D. melanogaster) | UAS-TNTE | Bloomington Drosophila Stock Center | BDSC: 28837; Flybase: FBst0028837 | NA |
| Genetic reagent (D. melanogaster) | tub-Gal80ts | Bloomington Drosophila Stock Center | NA | NA |
| Genetic reagent (D. melanogaster) | UAS-Ih-RF | This study or doi: 10.1101/2023.08.04.551918 | Flybase: FBtr0290109 | NA |
| Genetic reagent (D. melanogaster) | UAS-Ih RNAi | Bloomington Drosophila Stock Center | BDSC: 58089; Flybase: FBst0058089 | NA |
| Genetic reagent (D. melanogaster) | nompCf00642 | Korea Drosophila Resource Center | KDRC: K3137; Flybase: FBt0041920 | NA |
| Chemical compound, drug | Tricholine citrate | Sigma-Aldrich | Cat. #T0252 | |
| Chemical compound, drug | Caffeine | Sigma-Aldrich | Cat. #C0750 | |
| Chemical compound, drug | Berberine chloride form | Sigma-Aldrich | Cat. #B3251 | |
| Chemical compound, drug | Lobeline hydrochloride | Sigma-Aldrich | Cat. #141879 | |
| Chemical compound, drug | Umbelliferone | Sigma-Aldrich | Cat. #H24003 | |
| Chemical compound, drug | Theophylline anhydrous | Sigma-Aldrich | Cat. #T1633 | |
| Chemical compound, drug | Sucrose | Georgia Chem | Cat. #57-50-1 | |
| Chemical compound, drug | D-Sorbitol | Sigma-Aldrich | Cat. #S1876 | |
| Chemical compound, drug | N-methyl maleimide | Sigma-Aldrich | Cat. #389412 | |
| Software, algorithm | LabChart 8 | AD Instrument | https://www.adinstruments.com | NA |
| Software, algorithm | SigmaPlot 14.0 | Systat Software Inc | https://systatsoftware.com/ | NA |
