The FASEB Journal最新文献

Congenital heart disease (CHD) represents a major birth defect associated with substantial morbidity and mortality. Although environmental factors are acknowledged as potential contributors to CHD, the underlying mechanisms remain poorly understood. Bisphenol A (BPA), a common endocrine disruptor, has attracted significant attention due to its widespread use and associated health risks. This study examined the effects of maternal BPA exposure on fetal heart development in a murine model. The findings indicated that high-dose BPA exposure resulted in fetal growth restriction, myocardial wall thinning, and ventricular septal defects. Transcriptomic analysis revealed downregulation of genes associated with mitochondrial energy synthesis and cardiomyocyte development following high-dose BPA exposure. Functional assays demonstrated that high-dose BPA exposure impaired mitochondrial respiration reduced ATP production, disrupted mitochondrial membrane potential, and increased intracellular reactive oxygen species levels in fetal cardiomyocytes. These results elucidate the detrimental effects of BPA on fetal heart development and mitochondrial function, providing insights into potential mechanisms linking environmental chemical exposure to CHD.

Liver ischemia–reperfusion (IR) injury is a common complication following liver surgery, significantly impacting the prognosis of liver transplantation and other liver surgeries. Betaine-homocysteine methyltransferase (BHMT), a crucial enzyme in the methionine cycle, has been previously confirmed the pivotal role in hepatocellular carcinoma, and it has also been demonstrated that BHMT inhibits inflammation, apoptosis, but its role in liver IR injury remains unknow. Following I/R injury, we found that BHMT expression was significantly upregulated in human liver transplant specimens, mice and hepatocytes. Utilizing BHMT knockout mice, we established an in vivo model of liver IR injury, and with BHMT knockout and overexpression AML12 cell lines, we created an in vitro hypoxia–reoxygenation model. Our findings reveal that BHMT deficiency exacerbates liver IR injury, leading to increased reactive oxygen species, apoptosis and inflammation, whereas BHMT overexpression mitigates these effects. We observed that BHMT inhibits the c-Jun N-terminal kinase (JNK)/p38 signaling pathway in liver IR injury by interacting with TAK1 and inhibiting its activity. The application of 5z-7-ox, a TAK1 inhibitor, reversed the worsening of liver IR injury and the activation of the JNK/p38 pathway associated with BHMT deficiency. These results demonstrate that BHMT protects against liver IR injury by targeting TAK1 and inhibiting the JNK/p38 signaling pathway. Our findings suggest that BHMT may be a promising therapeutic target for preventing liver IR injury.

Adipose tissue (AT), is a major endocrine organ that plays a key role in health and disease. However, adipose dysfunctions, especially altered energy metabolism, have been under-investigated as white adipocytes have relatively low mitochondrial density. Nevertheless, recent studies suggest that mitochondria could play a major role in AT disorders and that AT mitochondrial activity could depend on adiposity level and location. This clinical study aimed to evaluate mitochondrial respiration and metabolism in human visceral (vAT) and subcutaneous (scAT) AT and their relationship with body mass index (BMI). This clinical study enrolled 67 patients (30 females/37 males) scheduled for digestive surgery without chemotherapy and parietal infection. BMI ranged from 15.4 to 51.9 kg·m⁻² and body composition was estimated by computed tomographic images. Mitochondrial respiration was measured in situ in digitonin-permeabilized AT using high-resolution respirometry and a substrate/inhibitor titration approach. Protein levels of mitochondrial and lipid metabolism key elements were evaluated by Western blot. Maximal mitochondrial respiration correlated negatively with BMI (p < .01) and AT area (p < .001) regardless of the anatomical location. However, oxidative phosphorylation respiration was significantly higher in vAT (2.22 ± 0.15 pmol·sec⁻¹·mg⁻¹) than scAT (1.79 ± 0.17 pmol·sec⁻¹·mg⁻¹) (p < 0.001). In line with oxygraphy results, there were higher levels of mitochondrial respiratory chain complexes in low-BMI patients and vAT. Mitochondrial respiration decreased with increasing BMI in both scAT and vAT, without sex-associated difference. Mitochondrial respiration appeared to be higher in vAT than scAT. These differences were both qualitative and quantitative. Clinical Trials Registration IDNCT05417581.

The smooth muscle cells (SMCs) located in the vascular media layer are continuously subjected to cyclic stretching perpendicular to the vessel wall and play a crucial role in vascular wall remodeling and blood pressure regulation. Mesenchymal stem cells (MSCs) are promising tools to differentiate into SMCs. Mechanical stretch loading offers an opportunity to guide the MSC-SMC differentiation and mechanical adaption for function regeneration of blood vessels. This study shows that cyclic stretch induces the expression of SMC markers α-SMA and SM22 in MSCs. These cells exhibit contractile ability in vitro and facilitate angiogenesis in the Matrigel plug assay in vivo. The contraction of SMCs requires remodeling of their energy metabolism. However, the underlying mechanism in the differentiation of MSCs into SMCs remains to be revealed. Cyclic stretch training promotes glycolysis, oxidative phosphorylation, and mitochondrial fusion and modulates mitochondrial dynamics-related proteins (MFN1, MFN2, DRP1) expression, thereby contributing to MSCs differentiation. Yes-associated protein (YAP) affects mitochondrial dynamics, oxidative phosphorylation, and glycolysis to regulate stretch-mediated differentiation into SMCs. Additionally, Piezo-type mechanosensitive ion channel component 1 (Piezo1) impacts energy metabolism and MSCs differentiation by regulating intracellular Ca²⁺ levels and YAP nuclear localization. It indicates that YAP can integrate stretch force and energy metabolism signals to regulate the differentiation of MSCs into SMCs.

This study aimed to investigate the effects of electroacupuncture (EA) at specific acupoints (DU20 and ST36) and different frequencies (2 and 100 Hz) on brain regions associated with trigeminal neuralgia, anxiety, and depression. Chronic trigeminal neuralgia was induced by the chronic constriction of the infraorbital nerve (CION). Anxiety and depression were assessed through behavioral tests. The effects of high-frequency (100 Hz) and low-frequency (2 Hz) EA at DU20 and ST36 were compared using immunofluorescence staining to evaluate their impact on pain, anxiety, depression, and brain activity. CION induced prominent trigeminal neuralgia in mice, accompanied by anxiety- and depression-like behaviors. Two weeks post-CION surgery increased neural activity was observed in the Prl, Cg1, CeA, BLA, TRN, CA3, CA1, vlPAG, PC5, and LPB brain regions, while reduced activity was noted in the PVN, VTA, and LDTgv regions. EA at 100 Hz applied to DU20 and ST36 rapidly alleviated pain and specifically reduced despair behavior, a depressive-like phenotype. In contrast, 2 Hz EA at the same acupoints addressed both anxiety- and depression-like behaviors, modulating a broader range of brain regions, including the PrL, BLA, PVN, VTA, vlPAG, and LDTgv, compared to 100 Hz EA. Repeated 2 Hz EA exclusively at DU20 was sufficient for analgesia and improvement of anxiety and depression, demonstrating a more extensive modulation of brain activity, particularly in the VTA and LDTgv, than EA at ST36. The study reveals that CION induces significant trigeminal neuralgia, accompanied by anxiety and depression, characterized by distinct neural activity patterns. EA at 2 Hz exhibits greater effectiveness in alleviating anxiety and depression, exerting broad modulation across various brain regions. Notably, EA at DU20 demonstrates superior modulation of brain activity and enhanced antidepressant and analgesic effects compared to ST36. These findings provide valuable insights into the nuanced therapeutic effects of EA on the interplay between chronic pain and affective disorders, suggesting potential clinical strategies for intervention.

Ghrelin is a gastric peptide that modulates various biological functions, including potential anti-inflammatory and antifibrotic properties. Increasingly evidence have demonstrated that exosomes derived from injured hepatocytes (IHC-Exo) can accelerate the activation of hepatic stellate cells (HSCs) and liver fibrosis. Ferroptosis, a type of novel programmed cell death, regulates diverse pathological processes, including liver fibrosis. However, it remains unclear whether ghrelin exerts its antifibrotic effect through mechanisms involving exosomes and ferroptosis. To explore the mechanism, IHC-Exo were isolated from supernatant of injured mouse primary hepatocytes (HCs) treated with palmitic acid (PA). Mouse primary HSCs and a bile duct ligation (BDL)-induced liver fibrosis murine model were then treated with IHC-Exo or exosomes derived from ghrelin-pretreated injured hepatocytes (GHR-IHC-Exo). The expression of α-SMA, Collagen I and long noncoding (lnc) RNA MALAT1 in HSCs were then detected. The ferroptosis of HSCs was evaluated by assessing the level of CCK8, MDA, GSH, and GPX4 expression. Mouse serum and liver biopsy samples were used to determine whether ferroptosis is involved in the progression of liver fibrosis. Nanoparticle tracking analysis and electron microscopy characterized the features of IHC-Exo. As the results suggested, compared with IHC-Exo, GHR-IHC-Exo treatment significantly promoted ferroptosis of HSCs, inhibited their activation, and consequently alleviated liver fibrosis progression in BDL mice. The inhibitory effect of GHR-IHC-Exo on activation of HSCs was partially reversed by treatment with the ferroptosis inhibitor Ferrostatin-1. The expression of lncMALAT1 was significantly down-regulated in GHR-IHC-Exo as compared to IHC-Exo. Serum exosome levels of MALAT1 were significantly higher in patients with severe liver fibrosis compared to those with mild liver fibrosis. Additionally, the expression of ferroptosis suppressor protein GPX4 was elevated as liver fibrosis progression, indicating decreased ferroptosis of HSCs in patients with severe liver fibrosis. In conclusion, Ghrelin reduced the pro-fibrotic effect of IHC-Exo in liver fibrosis by regulating lncMALAT1/GPX4 pathway mediated HSCs ferroptosis. Triggering HSCs ferroptosis via GHR-IHC-Exo may become a novel strategy to alleviate the progression of liver fibrosis.

Milk is a multifaceted biofluid that is essential for infant nutrition and development, yet its cellular and bioactive components, particularly maternal milk cells, remain understudied. Early research on milk cells indicated that they cross the infant's intestinal barrier and accumulate within systemic organs. However, due to the absence of modern analytical techniques, these studies were limited in scope and mechanistic analysis. To overcome this knowledge gap, we have investigated the transintestinal transport of milk cells and components in pups over a 21-day period. Studies employed a mT/mG foster nursing model in which milk cells express a membrane-bound fluorophore, tdTomato. Using flow cytometry, we tracked the transport of milk cell-derived components across local and systemic tissues, including the intestines, blood, thymus, mesenteric lymph nodes, and liver. These experiments identified milk-derived fluorescent signals in intestinal epithelial and immune cells as well as liver macrophages in 7-day-old pups. However, the minute numbers of macrophages in mouse milk suggest that maternal cells are not systemically accumulating in the infant; instead, pup macrophages are consuming milk cell membrane components, such as apoptotic bodies or extracellular vesicles (EVs). Ex vivo experiments using primary macrophages support this hypothesis, showing that immune cells preferentially consumed EVs over milk cells. Together, these data suggest a more complex interplay between milk cells and the infant's immune and digestive systems than previously recognized and highlight the need for future research on the role of milk cells in infant health.

Sarcopenia is an age-related muscle atrophy syndrome characterized by the loss of muscle strength and mass. Although many agents have been used to treat sarcopenia, there are no successful treatments to date. In this study, we identified Danshensu sodium salt (DSS) as a substantial suppressive agent of muscle atrophy. We used a D-galactose (DG)-induced aging-acceleration model, both in vivo and in vitro, to confirm the effect of DSS on sarcopenia. DSS inhibits the expression of muscle atrophy-related factors (MuRF1, MAFbx, myostatin, and FoxO3a) in DG-induced mouse C2C12 and human skeletal muscle cells. Additionally, DSS restored the diameter of reduced C2C12 myotubes. Next, we demonstrated that DSS stimulates AMPK and PGC1α through CaMKII. DSS inhibits the translocation of FoxO3a into the nucleus, thus inhibiting muscle atrophy in a calcium-dependent manner. DSS initiated the protein–protein interaction between FoxO3a and PGC1α. The reduction of the PGC1α-FoxO3a interaction by DG was restored by DSS. Also, DSS suppressed increased intracellular reactive oxygen species (ROS) by DG. In animal models, DSS administration improved mouse muscle mass and physical performance (grip strength and hanging test) under DG-induced accelerated aging conditions. These findings demonstrated that DSS attenuates muscle atrophy by inhibiting the expression of muscle atrophy-related factors. Therefore, DSS may be a potential therapeutic agent for the treatment of sarcopenia.

The kinases AMPK, and mTOR as part of either mTORC1 or mTORC2, are major orchestrators of cellular growth and metabolism. Phosphorylation of mTOR Ser1261 is reportedly stimulated by both insulin and AMPK activation and a regulator of both mTORC1 and mTORC2 activity. Intrigued by the possibilities that Ser1261 might be a convergence point between insulin and AMPK signaling in skeletal muscle, we investigated the regulation and function of this site using a combination of human exercise, transgenic mouse, and cell culture models. Ser1261 phosphorylation on mTOR did not respond to insulin in any of our tested models, but instead responded acutely to contractile activity in human and mouse muscle in an AMPK activity-dependent manner. Contraction-stimulated mTOR Ser1261 phosphorylation in mice was decreased by Raptor muscle knockout (mKO) and increased by Raptor muscle overexpression, yet was not affected by Rictor mKO, suggesting most of Ser1261 phosphorylation occurs within mTORC1 in skeletal muscle. In accordance, HEK293 cells mTOR Ser1261Ala mutation strongly impaired phosphorylation of mTORC1 substrates but not mTORC2 substrates. However, neither mTORC1 nor mTORC2-dependent phosphorylations were affected in muscle-specific kinase-dead AMPK mice with no detectable mTOR Ser1261 phosphorylation in skeletal muscle. Thus, mTOR Ser1261 is an exercise but not insulin-responsive AMPK-dependent phosphosite in human and murine skeletal muscle, playing an unclear role in mTORC1 regulation but clearly not required for mTORC2 activity.

Macrophage infiltration and activation is a key factor in the progression of diabetic nephropathy (DN). However, aerobic glycolysis induced by m6A methylation modification plays a key role in M1-type activation of macrophages, but the specific mechanism remains unclear in DN. In this study, the expression of m6A demethylase Fto in bone marrow derived macrophages and primary kidney macrophages from db/db mice. Loss and gain-of-function analysis of Fto were performed to assess the role of Fto in DN. Transcriptome and MeRIP-seq association analysis was performed to identified the target gene was Npas2. In this study, we found that demethylase Fto exhibits low expression in type 2 DN m6A modification of Npas2 mediated by Fto regulates macrophages M1-type activation and glucose metabolism reprogramming to participate in the process of DN. Furthermore, Fto reduces the m6A modification level of Npas2 in macrophages through a Prrc2a-dependent mechanism, and decreasing its stability. This process mediates inflammation and glycolysis in M1 macrophages by regulating the Hif-1α signaling pathway. Fto may act as a suppressor of M1 macrophages inflammation and glycolysis in DN through the m6A/Npas2/Hif-1α axis. This findings providing a new basis for the prevention and treatment of DN.