Chemogenetics Tools
Chemogenetics combines chemical reactions with genetic engineering to control the physiological activities of cells. The most widely used molecules include G protein-coupled receptors (GPCR) and ligand-gated ion channels, which are engineered so that they respond to specific small molecules rather than their endogenous ligands. Because of its controllable and reversible (compounds can be added or removed at any time to start or interrupt specific reactions), it has been widely used in the research of neural signal transduction.
There are many chemogenetics platforms based on GPCRs modification, such as allele-specific activation of genetically encoded receptors, receptors activated solely by synthetic ligands (RASSLs), genetically engineered receptors, and designer receptors exclusively activated by designer drugs (DREADDs). Among them, DREADDs has become the most widely used chemical genetics technology. DREADDs receptors are relatively insensitive to endogenous ligands, but can be activated by clozapine-N-oxide (CNO), which in turn triggers the G protein signaling cascade and leads to various physiological changes.
Fig.1 Schematic overview of how different variants of DREADDs (hM3Dq and hM4Di) can be used to activate
and also inhibit groups of neurons.
There are many DREADDs activated by azizapine-N-oxide. They will selectively act on different GPCR signaling cascades, including activation of Gq, Gi, Gs, Golf and β -arrestin. The most widely used DREADDs are Gq-DREADD and Gi-DREADD. Below is a list of representative DREADDs. Generally speaking, if you want to activate neurons, choose hM3Dq, and if you want to inhibit neuron activity, choose hM4Di.
Chemogenetic Receptors
| DREADD | Description | Ligand |
|---|---|---|
| hM3D(Gq) | Increase Ca2+, Activation | CNO |
| hM4D(Gi) | Decrease cAMP β/γ-GIRK activation, Inhibitory | CNO |
| KORD | Decrease cAMP β/γ-GIRK activation ,Inhibitory | SALB |
| Chemogenetics | Optogenetics | |
| Resolution |
Minutes, and CNO acts on neurons Takes 2 hours to remove from the membrane |
High temporal and spatial resolution. Sub-millisecond and millisecond level in neuron regulation. The spatial accuracy can reach the level of single cell. At the moment the light stops, the effects of light stimulation can almost stop at the same time |
| Experimental Operations |
Simple operation, only intraperitoneal injection or feeding is enough Compared with optogenetics, no need for craniotomy to embed fiber |
The operation is complicated, and it needs to bury the fiber, operate the laser controller and the catheter and other accessories |
| Experimental Duration | Continuous dosing is feasible Suitable for long-term neuronal loop regulation research | Due to mechanical limitations such as laser heat generation, Processing neurons for a long time is almost impossible |
| Cat | Product Name | Promoter | Cell Types | Key Components | Fluorescent | Expression |
| NTA-2011-ZP51 | pAAV-CaMKlla-DIO-hM4D(Gi)-eGFP | CaMKlla | Glutamatergic Neuron | DIO-hM4D(GI) | EGFP | Inducible Cre expression |
| NTA-2011-ZP52 | pAAV-EF1a-DIO-hM3D(Gq)-mCherry | EF1a | Broad spectrum | DIO-hM3D(Gq) | mCherry | Inducible Cre expression |
| NTA-2011-ZP53 | pAAV-EF1a-DIO-hM4D(Gi)-mCherry | EF1a | Broad spectrum | hM4D(Gi) | mCherry | Normal expression |
| NTA-2011-ZP54 | PAAV-GFAP-hM3D(Gq)-mcherry | GFAP | Astrocyte; Neural Stem Cell | hM3D(Gq) | mCherry | Normal expression |
| NTA-2011-ZP55 | PAAV-GFAP-hM4D(Gi)-mcherry | GFAP | Astrocyte; Neural Stem Cell | hM4D(GI) | mCherry | Normal expression |
| NTA-2011-ZP56 | pAAV-hSyn-DIO-hM3D(Gq)-mCherry | hSyn | Neuron | DIO-hM3D(Gq) | mCherry | Inducible Cre expression |
| NTA-2011-ZP57 | pAAV-hSyn-DI0-hM3D(Gq)-eGFP | hSyn | Neuron | DIO-hM3D(Gq) | EGFP | Inducible Cre expression |
| NTA-2011-ZP58 | pAAV-hSyn-DlO-hM4D(Gi)-mCherry | hSyn | Neuron | DIO-hM4D(Gi) | mCherry | Inducible Cre expression |
| NTA-2011-ZP59 | pAAV-hSyn-DIO-hM4D(Gi)-EGFP | hSyn | Neuron | DIO-hM4D(Gi) | EGFP | Inducible Cre expression |
| NTA-2011-ZP60 | pAAV-hSyn-HA-hM3D(Gq)-IRES-mCitrine | hSyn | Neuron | hM3D(Gq) | mCitrine | Normal expression |
| NTA-2011-ZP61 | pAAV-hSyn-HA-hM4D(GI)-IRES-mCtrine | hSyn | Neuron | hM4D(GI) | mCitrine | Normal expression |
| NTA-2011-ZP62 | pAAV-hSyn-hM4D(Gi)-mCherry | hSyn | Neuron | hM4D(GI) | mCherry | Normal expression |
How to use chemogenetics virus tools for research:
- Choose the right DREADDs receptor: Generally speaking, hM3Dq is selected for activating neurons and hM4Di for inhibiting neurons
- The genetic information is delivered to the target cells by injecting the virus into the body
- CNO administration and control neuronal activity by controlling the administration time of CNO
- Receptor validity verification: use electrodes to record the voltage changes inside and outside the neuron cell membrane to verify the validity of the DREADDs receptor
- Animal phenotype detection: confirm the effect of activating or inhibiting neuronal activity on experimental animals through experiments
Please don’t hesitate to contact us for more details.
