The inflammatory response after myocardial infarction (MI) is a precisely regulated process that greatly affects subsequent wound healing and remodeling. However, the understood about the process are still limited. Macrophages are critically involved in inflammation resolution after MI. Krüppel-like factor 9 (Klf9) is a C2H2 zinc finger-containing transcription factor that has been implicated in glucocorticoid regulation of macrophages. However, the contribution of Klf9 to macrophage phenotype and function in the context of MI remains unclear. Our study revealed that KLF9 deficiency results in higher mortality and cardiac rupture rate, as well as a considerable exacerbation in cardiac function. Single-cell RNA sequencing and flow cytometry analyses reveals that, compared to WT mice, Klf9-/- mice display excessive neutrophil infiltration, insufficient macrophage infiltration, and a reduced proportion of Monocyte-derived CD206+ macrophages post-MI. Moreover, the expression of IFN-γ-STAT1 pathway genes in Klf9-/- cardiac macrophages is dysregulated, characterized by insufficient expression at 1 day post-MI and excessive expression at day 3 post-MI. Mechanistically, Klf9 directly binds to the promoters of Stat1 gene, regulating its transcription. Overall, these findings indicates that Klf9 beneficially influences wound healing after MI through modulating macrophage recruitment and differentiation by regulating the IFN-γ-STAT1 signal pathway.

Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) remains a major challenge in the treatment of lung cancer. Cancer associated fibroblasts (CAFs) play a key role in promoting resistance to anti-cancer therapies. This study identified a subpopulation of CAFs characterized by the overexpression of collagen triple helix repeat-containing 1 (CTHRC1) through single-cell RNA sequencing of lung cancer patients undergoing EGFR-TKI treatment. These CTHRC1+ CAFs were enriched in drug-resistant tumors. Mechanistically, CTHRC1+ CAFs enhance the glycolytic activity of cancer cells by activating the TGF-β/Smad3 signaling pathway. Excess lactate produced in the process of glycolysis further upregulates CTHRC1 expression in CAFs through histone lactylation, creating a positive feedback loop that sustains EGFR-TKI resistance. The study also demonstrated that Gambogenic Acid, a natural compound, can disrupt this feedback loop, thereby improving the efficacy of EGFR-TKI therapy. Additionally, the presence of CTHRC1+ CAFs in tumor tissues could serve as a biomarker for predicting the response to EGFR-TKI therapy and patient prognosis. Overall, this study highlights the significant role of CAFs in EGFR-TKI resistance and suggests that targeting CTHRC1+ CAFs could be a promising strategy to overcome drug resistance in lung cancer.
© 2025. The Author(s).

Abstract Lipedema is a hereditary disorder characterized by excessive accumulation of subcutaneous adipose tissue in the limbs. The genetic causes and mechanisms underlying abnormal adipocyte expansion in lipedema, however, remain unknown. Here, we identify compound heterozygous mutations in the PROC gene in three lipedema patients from two unrelated consanguineous families. In vitro studies demonstrate the wild-type Protein C (PC), encoded by PROC, plays an inhibitory role in adipogenesis; conversely, the identified PC mutants, p.R271Q and p.R272H, fail to inhibit this process. In mice, the receptor of PC (PROCR) marks adipocyte progenitors, and conditional deletion of PROCR in these cells leads to an increased number of newborn adipocytes within white adipose tissue (WAT). Transcriptomic analysis alongside chemical blockage tests identifies HIF-1α as a primary downstream transcription factor mediating PC–PROCR signaling in adipogenesis. Furthermore, adipose biopsy samples from the patients’ thighs exhibit hyperplastic expansion of adipocytes, while single-nucleus RNA sequencing confirms increased adipogenic capacity and down-regulated HIF-1α activity in affected subjects. These findings establish PROC as the first causal gene for human lipedema and unveil a previously unexpected role of the PC–PROCR axis in orchestrating adipogenesis.

Arteriovenous malformations (AVMs) are characteristic of hereditary hemorrhagic telangiectasia. Loss-of-function mutations in the activin receptor-like kinase 1 (Alk1) are linked to hemorrhagic telangiectasia type 2.
Endothelial-specific deletion of Alk1, endothelial lineage tracing, transcriptomics of single-cell analysis, and electron microscopy were performed to examine the vascular phenotype and characteristics of ALK1-deficient endothelial cells (ECs) after EC-specific Alk1 deletion. Ischemia assays were used to examine the cell capacity for vascular malformation. Connectivity Map with transcriptomic analysis was applied to identify chemical compounds. Specific methods for arteriovenous malformations, such as micro-computed tomography, with other molecular and cell biological tools were also performed.
We performed endothelial-specific deletion of Alk1 in mice and found severe arteriovenous malformations and vascular leakage. The transcriptomics of single-cell analysis revealed a new distinctive cell cluster formed after Alk1 deletion where the cells coexpressed arterial and lymphatic endothelial markers. The analysis projected that these cells potentially originated from arterial ECs after Alk1 deletion. This new population was referred to as arterial-lymphatic-like ECs according to its cellular markers, and its appearance was validated in the pulmonary small arteries after Alk1 deletion. Transplantation of these cells caused vascular malformations. Endothelial lineage tracing confirmed that these new arterial-lymphatic-like ECs were derived from ALK1 depleted ECs, potentially arterial ECs. We discovered that SOX17 (SRY-box transcription factor 17) induction was responsible for the derivation of these arterial-lymphatic-like ECs. We showed that direct binding of MDM2 (mouse double minute 2) was required for Sox17 to execute this activity. Inhibition of MDM2 reduced the arteriovenous malformations in the mouse model.
Together, our studies revealed the mechanistic underpinnings of ALK1 signaling in regulating the endothelial phenotype and provided possibilities for new therapeutic strategies in hemorrhagic telangiectasia type 2.

Multiple genetic associations suggest a causative relationship between Th17-related genes coding for proteins, such as IL-17A, IL-23 and STAT3, and psoriasis. Further support for this link comes from the findings that neutralizing antibodies directed against IL-17A, IL-17RA and IL-23 are efficacious in diseases like psoriasis, psoriatic arthritis and ankylosing spondylitis. RORγt is a centrally positioned transcription factor driving Th17 polarization and cytokine secretion and modulation of RORγt may thus provide additional benefit to patients. However, RORγt also plays a role in the normal development of T cells in the thymus and genetic disruption of RORγt in the mouse leads to the development of lymphoma originating in the thymus. Whilst it is not established that down-regulation of RORγt activity would lead to the same consequence in humans, further understanding of the thymus effects is desirable to support progress of this target as a potential treatment of Th17-driven disease. Herein we present the characterisation of recently disclosed RORγt inverse agonists demonstrating target engagement and efficacy in vitro and in vivo against Th17 endpoints but requiring higher concentrations in vitro to affect thymocyte apoptosis.
Copyright: © 2025 Collins et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.