Two-Pore-Domain Potassium Channel TREK-1 Mediates Pulmonary Fibrosis through Macrophage M2 Polarization and by Direct Promotion of Fibroblast Differentiation

Associations Between Preoperative Shortness of Breath and Potassium Channels Gene Variations in Women With Breast Cancer

OBJECTIVES

Shortness of breath is a common symptom in patients with cancer. However, the mechanisms that underlie this troublesome symptom are poorly understood. Therefore, this study aimed to determine the prevalence of and associated risk factors for shortness of breath in women prior to breast cancer surgery and identify associations between shortness of breath and polymorphisms for potassium channel genes.

METHODS

Patients were recruited prior to breast cancer surgery and completed a self-report questionnaire on the occurrence of shortness of breath. Genotyping of single nucleotides polymorphism (SNPs) in potassium channel genes was performed using a custom array. Multiple logistic regression analyses were done to identify associations between the occurrence of shortness of breath and SNPs in ten candidate genes.

RESULTS

Of the 398 patients, 11.1% reported shortness of breath. These patients had a lower annual household income, a higher comorbidity burden, and a lower functional status. After controlling for functional status, comorbidity burden, genomic estimates of ancestry and self-reported race and ethnicity, the genetic associations that remained significant in the multiple regression analyses were for potassium voltage-gated channel subfamily D (KCND2) rs12673992, potassium voltage-gated channel modifier subfamily S (KCNS1) rs4499491, and potassium two pore channel subfamily K (KCNK2) rs4411107.

CONCLUSIONS

While these findings warrant replication, they suggest that alterations in potassium channel function may contribute to the occurrence of shortness of breath in women prior to breast cancer surgery.

Macrophage polarization and its impact on idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lung disease that worsens over time, causing fibrosis in the lungs and ultimately resulting in respiratory failure and a high risk of death. Macrophages play a crucial role in the immune system, showing flexibility by transforming into either pro-inflammatory (M1) or anti-inflammatory (M2) macrophages when exposed to different stimuli, ultimately impacting the development of IPF. Recent research has indicated that the polarization of macrophages is crucial in the onset and progression of IPF. M1 macrophages secrete inflammatory cytokines and agents causing early lung damage and fibrosis, while M2 macrophages support tissue healing and fibrosis by releasing anti-inflammatory cytokines. Developing novel treatments for IPF relies on a thorough comprehension of the processes involved in macrophage polarization in IPF. The review outlines the regulation of macrophage polarization and its impact on the development of IPF, with the goal of investigating the possible therapeutic benefits of macrophage polarization in the advancement of IPF.

Single-cell RNA sequencing reveals S100a9hi macrophages promote the transition from acute inflammation to fibrotic remodeling after myocardial ischemia‒reperfusion

Rationale: The transition from acute inflammation to fibrosis following myocardial ischemia‒reperfusion (MIR) significantly affects prognosis. Macrophages play a pivotal role in inflammatory damage and repair after MIR. However, the heterogeneity and transformation mechanisms of macrophages during this transition are not well understood. Methods: In this study, we used single-cell RNA sequencing (scRNA-seq) and mass cytometry to examine murine monocyte-derived macrophages after MIR to investigate macrophage subtypes and their roles in the MIR process. S100a9-/- mice were used to establish MIR model to clarify the mechanism of alleviating inflammation and fibrosis after MIR. Reinfusion of bone marrow-derived macrophages (BMDMs) after macrophage depletion (MD) in mice subjected to MIR were performed to further examine the role of S100a9hi macrophages in MIR. Results: We identified a unique subtype of S100a9hi macrophages that originate from monocytes and are involved in acute inflammation and fibrosis. These S100a9hi macrophages infiltrate the heart as early as 2 h post-reperfusion and activate the Myd88/NFκB/NLRP3 signaling pathway, amplifying inflammatory responses. As the tissue environment shifts from proinflammatory to reparative, S100a9 activates transforming growth factor-β (Tgf-β)/p-smad3 signaling. This activation not only induces the transformation of myocardial fibroblasts to myofibroblasts but also promotes fibrosis via the macrophage-to-myofibroblast transition (MMT). Targeting S100a9 with a specific inhibitor could effectively mitigate acute inflammatory damage and halt the progression of fibrosis, including MMT. Conclusion: S100a9hi macrophages are a promising therapeutic target for managing the transition from inflammation to fibrosis after MIR.

Macrophage Implication in IPF: Updates on Immune, Epigenetic, and Metabolic Pathways

Idiopathic pulmonary fibrosis (IPF) is a lethal interstitial lung disease of unknown etiology with a poor prognosis. It is a chronic and progressive disease that has a distinct radiological and pathological pattern from common interstitial pneumonia. The use of immunosuppressive medication was shown to be completely ineffective in clinical trials, resulting in years of neglect of the immune component. However, recent developments in fundamental and translational science demonstrate that immune cells play a significant regulatory role in IPF, and macrophages appear to be among the most crucial. These highly plastic cells generate multiple growth factors and mediators that highly affect the initiation and progression of IPF. In this review, we will provide an update on the role of macrophages in IPF through a systemic discussion of various regulatory mechanisms involving immune receptors, cytokines, metabolism, and epigenetics.