Optogenetic control of inputs to the ventral tegmental area
The present disclosure provides a method of inducing or modulating reward- or aversive-related behaviors in animals using light-responsive opsins. The present disclosure provides methods of identifying or screening compounds that may be used to treating mental disorders, or are relevant to disrupt or improve reward- or aversive related behaviors.
1. A method of modulating a reward- or aversive-related behavior in a mammal, the method comprising:
a) expressing in one or both of a laterodorsal tegmentum (LDT) neuron and a lateral habenula (LHb) neuron projecting to the ventral tegmental area (VTA):
i) a depolarizing light-responsive opsin polypeptide that comprises an amino acid sequence having at least about 90% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs:5-11; or
ii) a hyperpolarizing light-responsive opsin that comprises an amino acid sequence having at least about 90% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs:1, 4, 12, 14, and 15; and
b) exposing the LDT neuron and/or the LHb neuron to light,
wherein said exposing activates the light-responsive opsin polypeptide, thereby hyperpolarizing or depolarizing the neuron, and wherein said hyperpolarizing or depolarizing modulates a reward- or aversive-related behavior in the mammal.
2. The method of claim 1 , wherein said hyperpolarizing light-responsive opsin polypeptide comprises an amino acid sequence having at least about 95% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs: 1, 4, 12, 14, and 15, and wherein said depolarizing comprises an amino acid sequence having at least about 90% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs:5-11.
3. The method of claim 1 , wherein said light-responsive opsin polypeptide comprises an amino acid sequence having at least about 90% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs:5-11, wherein the method comprises exposing the LDT to light of a wavelength that activates the light-responsive polypeptide, thereby increasing the reward-related behavior.
4. The method of claim 3 , wherein said light-responsive opsin polypeptide comprises an amino acid sequence having at least about 95% amino acid sequence identity to an amino acid sequence selected from SEQ ID NOs:5-11.
5. The method of claim 3 , wherein said expressing comprises directly delivering into the LDT neuron a nucleic acid comprising a nucleotide sequence encoding the light-responsive opsin polypeptide.
6. The method of claim 5 , wherein the nucleic acid is a recombinant viral expression vector.
7. The method of claim 6 , wherein the recombinant viral expression vector is a lentiviral vector or an adeno-associated viral vector.
8. The method of claim 5 , wherein the nucleotide sequence is operably linked to a promoter.
9. The method of claim 8 , wherein the promoter is an EF1α promoter, a cytomegalovirus promoter, a CAG promoter, a synapsin-I promoter, a synuclein 1 promoter, a CAMKIIα promoter.
10. The method of claim 1 , wherein the light is provided by an implantable light source.
11. The method of claim 10 , wherein the light source comprises a light-emitting diode.
12. The method of claim 3 , wherein the light-responsive opsin polypeptide comprises a membrane trafficking signal comprising the amino acid sequence KSRITSEGEYIPLDQIDINV (SEQ ID NO:16).
13. The method of claim 3 , wherein the light-responsive opsin polypeptide comprises an endoplasmic reticulum export signal comprising the amino acid sequence FCYENEV (SEQ ID NO: 17).
14. The method of claim 1 , wherein the reward-related behavior is addiction.