遠藤 仁司

UNLABELLED: Krüppel-like factor 5 (KLF5) is an intrinsically disordered transcription factor involved in cardiac remodeling, cancer, and metabolic diseases. Targeting KLF5 has been a persistent challenge in drug development due to its structural inaccessibility. We investigated cardioprotective effects of NC114, a rationally designed small molecule that mimics a short, hydrophobic α-helical motif in KLF5, thereby disrupting its protein–protein interactions. Adult C57BL/6J male mice underwent transverse aortic constriction (TAC) or sham surgery, followed by administration of NC114 or vehicle. NC114-treated TAC mice exhibited preserved cardiac function, reduced heart weight-to-body weight ratio, and markedly attenuated interstitial fibrosis. Gene expression analysis demonstrated decreased cardiac expression of Klf5, Nppb, Tgfb1, PAI-1, Col1a1, and Fn1. NC114 also suppressed oxidative stress and reduced phosphorylation of PKCδ and expression of HIF-1α during the early phase post-TAC. Metabolomic profiling revealed that NC114 treatment reversed TAC-induced accumulation of organic and amino acids. NC114, a novel peptidomimetic molecule, targets the undruggable transcription factor KLF5 to attenuate cardiac hypertrophy, fibrosis, and metabolic dysregulation in pressure overload-induced heart failure. This study highlights the potential of KLF5 inhibition as a therapeutic strategy in cardiovascular disease. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-025-32155-y.

Abstract Leukemia cells are consistently subjected to higher oxidative stress than normal cells. To mitigate reactive oxygen species (ROS) overload, which can trigger various forms of cell death, leukemia cells employ a robust antioxidant defense system and maintain redox homeostasis. Recent evidence suggests that dimethyl fumarate (DMF), a derivative of fumarate, inactivates the antioxidant glutathione (GSH), thereby inducing oxidative stress and metabolic dysfunction, eventually leading to cell death in cancer cells. In this study, we observed that DMF decreases the GSH/oxidated GSH ratio and increases intracellular ROS levels, the extent of which is closely correlated with cell death, in acute myeloid leukemia (AML) cell lines. DMF reduced the mitochondrial membrane potential and oxidative phosphorylation (OXPHOS), effects that were almost fully restored by the antioxidant N-acetylcysteine, suggesting that these responses are ROS-dependent. Electron microscopy and inhibition assays revealed that apoptosis, rather than necroptosis or ferroptosis, is the predominant form of cell death of AML cells following DMF treatment. Notably, the combination of DMF and the BCL-2 selective BH3-mimetic venetoclax induced marked cell death in AML cells, including venetoclax-refractory BCL-2 low expressing U937 and acquired venetoclax-resistant MOLM-14 cells. This combination also caused greater mitochondrial depolarization and a more profound reduction in OXPHOS activity than either agent alone. Collectively, our findings indicate that DMF exerts potent anti-leukemia activity in AML cells and sensitizes cells to venetoclax treatment by synergistically disrupting mitochondrial integrity through ROS accumulation.

ABSTRACT Recent evidence indicates that the TCA cycle metabolite fumarate plays a specific role in modulating signaling pathways in immune cells. We have previously shown that dimethyl fumarate (DMF) reduces glutathione (GSH) activity and causes the accumulation of cellular reactive oxygen species (ROS), thereby compromising effector immune responses and metabolic activities in activated T‐cells. However, the precise mechanism by which DMF modulates T‐cell signaling pathways remains to be elucidated. This study demonstrates that DMF inhibits T‐cell proliferation, independent of T‐cell receptor (TCR) engagement, and this response is fully reversible by replenishing GSH. Immunoblot analysis showed that DMF had different impacts on TCR downstream signaling by decreasing MYC expression while promoting the phosphorylation of Akt and Erk1/2. Cell cycle analysis demonstrated that exposure to DMF led to negative regulation of cell cycle‐related proteins and induced T‐cells into G0/G1 arrest, which was also rescued by antioxidants. Several genes related to GSH synthesis were upregulated at the same time, suggesting that a potential compensatory response may occur to reduce oxidative burst following DMF treatment. Our results suggest that DMF‐mediated oxidative stress alters a range of cell signaling pathways, including MYC, leading to cell cycle arrest and a defective proliferative response of T‐cells during activation.

Objectives Compared to conventional disease-modifying antirheumatic drugs (DMARDs), biological DMARDs demonstrate superior efficacy but come with higher costs and increased infection risks. The ability to stop and resume biological DMARD treatment while maintaining remission would significantly alleviate these barriers and anxieties. The objective of this study was to identify biomarkers that can predict an imminent relapse, hopefully enabling the timely resumption of biological DMARDs before relapse occurs. Methods Forty patients with rheumatoid arthritis who had been in remission for more than 12 months were included in the study. The patients discontinued their biological DMARD treatment and were monitored monthly for the next 24 months. Out of the 40 patients, 14 (35%) remained in remission at the end of the 24-month period, while 26 (65%) experienced relapses at different time points. Among the relapse cases, 13 patients experienced early relapse within 6 months, and another 13 patients had late relapse between 6 months and 24 months. Seventy-three cytokines in the sera collected longitudinally from the 13 patients with late relapse were measured by multiplex immunoassay. Using cytokines at two time points, immediately after withdrawal and just before relapse, volcano plot and area under the receiver operating characteristic curves (AUC) were drawn to select cytokines that distinguished imminent relapse. Univariate and multivariate logistic regression analyses were used for the imminent relapse prediction model. Results IL-6, IL-29, MMP-3, and thymic stromal lymphopoietin (TSLP) were selected as potential biomarkers for imminent relapse prediction. All four cytokines were upregulated at imminent relapse time point. Univariate and multivariate logistic regression showed that a combination model with IL-6, MMP-3, and TSLP yielded an AUC of 0.828 as top predictors of imminent relapse. Conclusions This methodology allows for the prediction of imminent relapse while patients are in remission, potentially enabling the implementation of on- and off-treatments while maintaining remission. It also helps alleviate patient anxiety regarding the high cost and infection risks associated with biological DMARDs, which are the main obstacles to benefiting from their superb efficacy.

Although the role of aerobic glycolysis in activated T cells has been well characterized, whether and how fatty acids (FAs) contribute to donor T cell function in allogeneic hematopoietic stem cell transplantation is unclear. Using xenogeneic graft-versus-host disease (GVHD) models, this study demonstrated that exogenous FAs serve as a crucial source of mitochondrial respiration in donor T cells in humans. By comparing human T cells isolated from wild-type NOD/Shi-scid-IL2rγnull (NOG) mice with those from MHC class I/II-deficient NOG mice, we found that donor T cells increased extracellular FA uptake, the extent of which correlates with their proliferation, and continued to increase FA uptake during effector differentiation. Gene expression analysis showed the upregulation of a wide range of lipid metabolism-related genes, including lipid hydrolysis, mitochondrial FA transport, and FA oxidation. Extracellular flux analysis demonstrated that mitochondrial FA transport was required to fully achieve the mitochondrial maximal respiration rate and spare respiratory capacity, whereas the substantial disruption of glucose supply by either glucose deprivation or mitochondrial pyruvate transport blockade did not impair oxidative phosphorylation. Taken together, FA-driven mitochondrial respiration is a hallmark that differentiates TCR-dependent T cell activation from TCR-independent immune response after hematopoietic stem cell transplant.