Genetic prioritization and functional characterization of macrophage TXNDC17 in Ischemic heart disease

Ischemic heart disease (IHD) still works as the leading cause of mortality through the world. Endoplasmic reticulum (ER) stress is a key player in the pathogenesis of IHD. However, the potential mechanisms and key regulatory factors remain not fully clear.

In our research, single-cell RNA sequencing data were integrated with summary-data-based Mendelian randomization (SMR) and colocalization analyses, aimed at systematically recognizing ER stress-related genes associated with IHD and to evaluate genetically predicted associations with IHD. The selected candidate was subsequently examined using single-cell expression analysis and in vitro experiments involving pro-inflammatory THP-1 macrophage-like cells and AC16 cardiomyocytes. Cytokine expression in macrophages was assessed by quantitative PCR, whereas cytokine concentrations in OGD-conditioned medium were measured by enzyme-linked immunosorbent assay. Recipient-cell ER-stress and ferroptosis-associated responses were evaluated using molecular, biochemical and pharmacological rescue assays.

A total of 2564 genes associated with both IHD and ER stress were identified, enriched in pathways related to oxidative stress, protein folding, and apoptotic signalling. Integrative SMR, colocalization and Mendelian randomization analyses identified a genetically predicted inverse association between TXNDC17 expression and IHD risk, thereby prioritizing TXNDC17 for subsequent functional investigation. Pseudotemporal analysis revealed a dynamic alteration in TXNDC17 expression during myeloid cell development, with an initial increase followed by a subsequent decrease. Experimental validation revealed that TXNDC17 was highly expressed in myeloid cells and that its knockdown in macrophages aggravated OGD-induced injury, increased pro-inflammatory cytokine production and release, and increased apoptosis-associated injury. OGD-conditioned medium from TXNDC17-silenced macrophages further promoted ER stress- and ferroptosis-associated injury in cardiomyocytes.

Genetically predicted TXNDC17 expression was inversely associated with IHD risk. Functional experiments further implicated macrophage TXNDC17 in regulating inflammatory conditioned-medium-mediated cardiomyocyte injury, although its causal relevance to IHD in vivo remains to be established.