Macrophage-driven inflammation critically shapes lung injury outcomes. We propose that a BK–TRPC ion channel axis controls macrophage calcium signaling and polarization. Dysregulation of this pathway sustains pro-inflammatory responses and tissue damage, while targeted TRPC modulation may restore resolution, offering a novel ion-channel–based therapeutic strategy for inflammatory and fibrotic lung disease.
Project Details
Background:
Calcium (Ca²⁺) signaling plays a central role in orchestrating macrophage polarization between pro-inflammatory (M1) and reparative (M2) phenotypes, especially during lung injury. Sustained Ca²⁺ influx, predominantly mediated by Transient Receptor Potential Canonical (TRPC) channels, is essential for initiating and maintaining M1 polarization through pathways such as STAT1 and NF-κB1. The activity of these Ca²⁺-permeable channels is tightly regulated by the membrane potential (Vₘ), which in turn is governed by K⁺ conductance. Among potassium channels, the large-conductance Ca²⁺-activated K⁺ (BK) channel has emerged as a crucial modulator of macrophage electrophysiology2. By promoting K⁺ efflux, BK channels help maintain a hyperpolarized Vₘ, thereby limiting the electrochemical drive for TRPC-mediated Ca²⁺ influx. Loss or inhibition of BK channels leads to membrane depolarization, amplifying Ca²⁺ entry via TRPC channels and skewing macrophage polarization toward a sustained pro-inflammatory M1 phenotype.
Hypothesis and Objectives:
We hypothesize that this TRPC–BK channel feedback axis is a key regulator of macrophage Ca²⁺ homeostasis during lung injury. Disruption of BK channel function elevates basal Ca²⁺ levels and blunts stimulus-evoked Ca²⁺ responses, promoting sustained inflammation and tissue damage. This integrated approach will reveal whether a BK–TRPC axis controls macrophage Ca²⁺ homeostasis and polarization in lung injury, and whether targeting this axis can shift macrophage responses toward resolution. This could provide a novel ion-channel-based strategy to treat inflammatory and fibrotic lung disease. The PhD student will investigate the contribution of TRP channels to Ca²⁺ homeostasis and macrophage polarization, and extend these findings to pulmonary vascular cells to explore cross-tissue relevance using photoswitchable TRPC modulators.
Methodology:
Bone marrow–derived macrophages (BMDMs) from both murine models (wild-type and BK knockout) will be analyzed functionally by patch-clamp electrophysiology and live-cell Ca²⁺ imaging to measure Vₘ and TRPC-mediated Ca²⁺ influx across M0, M1 and M2 states. Pharmacological TRPC inhibitors and siRNA knockdown will employed and downstream readouts will include polarization markers, transcriptomics, and metabolic profiling. BMDMs from WT or BK⁻/⁻ mice co-cultured with endothelial cells to measure cytokine transfer, barrier integrity (TEER), and TRPC activity. These studies will determine the feasibility of selective, light-controlled TRPC modulation as a therapeutic strategy to fine-tune macrophage-driven inflammation in lung injury. BK KO mice to intratracheal LPS (acute lung injury) and, in parallel, to bleomycin (lung injury induced fibrosis model) to evaluate both early inflammatory and late reparative/fibrotic outcome. Bronchoalveolar lavage, lung histology, immune cell profiling and cytokine quantification will be used to assess injury severity and resolution. Bioinformatic analysis of RNA-seq data and multi-omics integration will be employed to identify ion channel–regulated inflammatory and reparative programs.
References
- Viviane Nascimento Da Conceicao, iScience,2021,24 (11),
- Chen, Y.Cells 2024, 13(4), 322;
People Involved
Primary supervisor: Chandran Nagaraj