# Unveiling and Exploiting the Structural Determinants of HCN2 Channel Selectivity

> **NIH NIH F31** · ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI · 2022 · $46,752

## Abstract

PROJECT SUMMARY
Depression is a devastating disease, and one of the leading causes of disability worldwide. However, one third
of patients are treatment resistant to the current antidepressants available. Therefore, a new antidepressant in
a different pharmacological class from the current antidepressants is vital. Targeting the HCN (hyperpolarization-
activated, cyclic nucleotide-gated) channel via a non-subtype-selective HCN inhibitor has demonstrated
antidepressant activity in mice. However, the HCN channel is critically present in both the brain and the heart;
thus a non-subtype-selective HCN inhibitor for brain disorders would be expected to have cardiac toxicity. To
solve this issue, my project will seek to target the HCN2 channel, the major subtype in the brain, without targeting
the HCN4 channel, the major subtype in the heart. The aim of this project is to define HCN2 selectivity, both in
compound selectivity towards HCN2 and the HCN2 channel’s residues contributing to selectivity. We first aim to
elucidate the compound chemotype associated with selectivity/preferentiality towards the HCN2 channel over
the HCN4 channel. This approach will utilize functional electrophysiology to test the effect of different compound
analogs on the Ih (hyperpolarization-activated) currents of HCN2- and HCN4-transfected HEK293 cells, and to
test the physiological effect of these compounds on dopamine neurons in the ventral tegmental area (VTA) of
the mouse brain (majority HCN2 channels) and cardiomyocytes (majority HCN4). Further, we will employ the
SplitLuc CETSA (cellular thermal shift assay) technique to measure the strength of the binding affinity of these
compounds for HCN2 over HCN4 channels. These parallel strategies will help to identify compound chemotypes
associated with functional and binding selectivity to the HCN2 channel. Our second aim is to establish the HCN2
channel residues and corresponding binding pocket associated with HCN2 selectivity versus HCN4. This
approach will utilize a systematic mutagenesis strategy of replacing HCN2 and HCN4 differing residues with one
another, followed by functional and binding selectivity testing (electrophysiology and CETSA) of the effect of the
probe 7G, an HCN2-preferential compound, on these mutants. Upon determination of residues associated with
7G selectivity for the HCN2 channel over the HCN4 channel, in silico docking of 7G onto the HCN2 channel
open and closed models (as well as the HCN4 channel open and closed solved structures) will be used to define
the binding pocket. Overall, this project will provide a multifaceted characterization of HCN2 selectivity,
contributing seminal HCN channel subtype-selectivity experiments to the growing body of HCN channel
literature. Additionally, compounds developed can be utilized to elucidate the effect of HCN2 channels in rodent
behavior and brain functions/dysfunctions, and the identification of an HCN2-selective chemotype, binding
pocket, and possibly compoun...

## Key facts

- **NIH application ID:** 10607061
- **Project number:** 1F31MH131358-01A1
- **Recipient organization:** ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
- **Principal Investigator:** Emily May Teichman
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $46,752
- **Award type:** 1
- **Project period:** 2022-09-07 → 2025-08-21

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10607061

## Citation

> US National Institutes of Health, RePORTER application 10607061, Unveiling and Exploiting the Structural Determinants of HCN2 Channel Selectivity (1F31MH131358-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10607061. Licensed CC0.

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