American journal of physiology. Cell physiology最新文献

Ischemic heart disease, the most common form of heart disease worldwide, is caused by a lack of oxygen and nutrients in the heart due to the narrowing of coronary arteries. Research in this field is mostly limited to animal models, but the development of cellular models could significantly accelerate the discovery of novel therapeutic molecules to protect cardiomyocytes from ischemic stress. To address this limitation, this study focused on developing an in vitro model of ischemic stress using human cardiomyocytes derived from induced pluripotent stem cells. After differentiating induced pluripotent stem cells into cardiomyocytes, the cells, cultured either in monolayers or as a spheroid, were exposed to an ischemic environment characterized by oxygen and nutrient deprivation. Specifically, we reduced the oxygen concentration to 1% using a hypoxia chamber and the glucose concentration to 65 mg/L to trigger the onset of cardiac ischemia. Twenty-four hours later, the stressed cardiomyocytes were treated with tumor necrosis factor alpha (TNF-α, 20 ng/mL) and interleukin 6 (IL-6, 20 ng/mL) to also mimic the inflammatory environment. The cells were then analyzed at various timepoints following exposure to ischemic stress. Our results showed that this novel ischemia model induces progressive cellular toxicity characterized by increased apoptosis, double-stranded DNA breaks, and overall cell death. These effects are accompanied by mitochondrial and metabolic dysfunction, loss of cardiomyocyte contractile function, and numerous morphological alterations, including reduced cell and nuclei size and disorganization of the α-actinin network. In conclusion, our results highlight that this model offers a valuable platform for understanding the mechanistic underpinnings of cardiomyocyte ischemic stress and holds promise for screening novel therapeutic molecules aimed at protecting cardiomyocytes. Furthermore, by reducing reliance on animal models, it adheres to the reduction, replacement, and refinement (3Rs) ethical principles.NEW & NOTEWORTHY In this study, we developed a novel in vitro model of cardiac ischemia using cardiomyocytes derived from induced pluripotent stem cells. Cells were exposed to oxygen and nutrient deprivation, followed by proinflammatory cytokines to mimic postischemic inflammation. This approach reproduces key features of ischemic injury, including mitochondrial dysfunction, impaired contractility, and morphological changes. The model provides a valuable tool for studying cardiac pathophysiology and testing therapeutic strategies while reducing reliance on animal models.

Cardiovascular-kidney-metabolic (CKM) syndrome affects approximately 90% of US adults, arising from the convergence of metabolic dysfunction, chronic kidney disease (CKD), and cardiovascular disease (CVD). These conditions create self-reinforcing cycles of multiorgan damage, substantially increasing mortality risk. The American Heart Association's 2023 staging framework stratifies CKM from stage 0 (no risk factors) through stage 4 (clinical CVD with persistent metabolic dysfunction), informing stage-specific interventions. This review synthesizes current evidence on CKM epidemiology, pathophysiology, and disease trajectories. Population-based studies reveal that stage 2 (metabolic risk factors or early CKD) represents the most prevalent category, affecting nearly half of adults in Western cohorts. Progression occurs in 34% of stage 1 individuals, with each stage transition conferring an incrementally higher cardiovascular mortality risk. We describe the biological cascade linking dysfunctional adiposity, insulin resistance, and endothelial dysfunction to renal and cardiac damage, emphasizing bidirectional organ cross talk and the emerging role of hepatic pathology [metabolic dysfunction-associated steatotic liver disease (MASLD)/metabolic dysfunction-associated steatohepatitis (MASH)] in CKM progression. Finally, we examine stage-specific interventions, from lifestyle modification and weight-loss pharmacotherapy (GLP-1 agonists and dual agonists) in early stages to multidrug cardiorenal protection [sodium-glucose cotransporter-2 (SGLT2) inhibitors and renin-angiotensin-aldosterone system (RAAS) blockade] in advanced disease. This framework allows targeted risk stratification and evidence-based management to interrupt CKM trajectories and improve population health outcomes.

Vascular dysfunction, particularly vascular hyporeactivity, has been identified as a critical factor for limiting the treatment of patients with traumatic hemorrhagic shock (THS). Nevertheless, the precise mechanisms underlying THS-induced vascular dysfunction remain inadequately understood. Increasing attention has been directed toward the role of Golgi apparatus stress (GAS)-induced cell death in cardiovascular disease, closely linked to redox imbalance. Recent studies indicate that inhibition of connexin43 (Cx43, a key regulator of vascular dysfunction) induces ferroptosis. However, it remains unclear whether THS-induced vascular dysfunction is regulated by GAS through Cx43 and ferroptosis. In this study, we showed that GAS was responsible for inducing vascular hyporeactivity following THS. Using a Cx43-knockout mice model, we subsequently found that GAS reduced the reactivity of superior mesenteric arteries after THS based on the inhibition of Cx43. Furthermore, cell experiments showed that hypocontraction of vascular smooth muscle cells (VSMCs) was induced by GAS; meanwhile, gap junctional intercellular communication (GJIC) disruption and ferroptosis were also triggered. We generated Cx43-knockdown or overexpressed VSMCs and verified that GAS induced hypocontraction of VSMCs through inhibition of Cx43 and SLC7A11. Moreover, increasing the level of SLC7A11 could attenuate GAS-induced ferroptosis and hypocontraction of VSMCs. These results suggest that GAS-induced ferroptosis can cause vascular dysfunction, which is mediated by the inhibition of the Cx43-SLC7A11 pathway in THS.NEW & NOTEWORTHY The results highlight the important role of Golgi stress and ferroptosis in traumatic hemorrhagic shock-induced vascular dysfunction and inhibition of Golgi stress and its target pathway (connexin43-SLC7A11 pathway) may be the potential therapeutic target.

Astrocytes are fundamental for brain homeostasis and act as dynamic signaling elements within the central nervous system. By maintaining ionic balance, neurotransmitter turnover, and metabolic support, they sustain neuronal excitability and network stability. Ionic excitability of astrocytes is mediated primarily by fluctuations of intracellular Na⁺, K⁺, Ca²⁺, and Cl^- ions. Central to these processes is the Na⁺,K⁺-ATPase, which maintains transmembrane Na⁺ and K⁺ gradients, driving secondary active transport, including uptake of neurotransmitters such as glutamate, γ-aminobutyric acid, and their precursors glutamine and L-serine. Astrocytic Na⁺ changes rapidly coordinate neuronal activity with glial homeostasis via N-methyl-d-aspartate receptor signaling, whereas K⁺ clearance is primarily mediated by the Na⁺,K⁺-ATPase α₂ isoform, preventing neuronal hyperexcitability. The Na⁺,K⁺-ATPase also contributes to neurovascular coupling, linking synaptic activity to local vasodilation through Ca²⁺- and K⁺-dependent signaling in astrocytic endfeet. Beyond ion transport, the Na⁺,K⁺-ATPase serves as a signaling hub, engaging intracellular kinase signaling pathways, including Src and phosphoinositide 3-kinase kinases, thereby modulating astrocyte morphology, metabolism, and stress responses. Dysfunctions of astrocytic Na⁺,K⁺-ATPase isoforms are implicated in multiple neuronal pathologies, including seizures, familial hemiplegic migraine, neurodegeneration, and neuroinflammatory disorders. These pathologies reflect primarily loss-of-function mechanisms, altered ion homeostasis, and reactive oxygen species or inflammatory signaling. Understanding the isoform- and cell-type-specific functions of the Na⁺,K⁺-ATPase across the neurovascular unit will be crucial for future development of targeted therapies aimed to restore ion homeostasis and signaling in the diseased brain.

Pediatric cancer survival now exceeds 85% owing, in part, to advances and the use of combination chemotherapy treatments such as CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone). Despite its efficacy, CHOP may cause off-target effects during critical pediatric development periods such as impairments of skeletal muscle. We evaluated the acute effects of a CHOP administered to C57Bl/6J mice from postnatal day 28 to 48. CHOP slowed body-weight gain and led to a smaller gastrocnemius fiber cross-sectional area by ∼25% in both sexes (n = 11 or 12 males; n = 8 or 9 females). RNA sequencing detected 214 differentially expressed genes in males and 217 in females relative to controls, yet only 29 transcripts overlapped. Males exhibited downregulation of myogenic regulators, indicating impaired progenitor maintenance, whereas females showed an upregulation of extracellular-matrix and translational machinery genes plus cell-cycle regulators. Using immunohistochemistry to assess satellite cell abundance, there were 60% fewer satellite cells in males and 40% fewer in females, which supported our transcriptional findings. These results demonstrate that pediatric CHOP acutely disrupts muscle stem-cell dynamics via sex-specific molecular programs and identify satellite cells as a potential target for preserving muscle health in pediatric cancer survivors.NEW & NOTEWORTHY Multiagent CHOP chemotherapy in juvenile mice impairs muscle growth and alters transcriptional programs in a sex-specific manner. CHOP-treated mice showed lower satellite cell abundance and smaller muscle fibers, with RNA-seq revealing distinct gene expression profiles enriched for myogenic regulators, extracellular matrix, and translational machinery. These findings highlight the negative effects of chemotherapy on developing muscle and suggest alterations to satellite cells as a key contributor.

Cancer-induced inflammation has been widely investigated as a driver of cachexia, and sex can affect the inflammatory response to cancer. We have an incomplete understanding of how anticancer treatments and sex impact the relationship between inflammatory responses and changes to body composition and physical function during cancer treatment. We investigated the effect of FOLFOX chemotherapy (5-fluorouracil, leucovorin, oxaliplatin) on circulating inflammatory cytokines, body composition, and physical function in CT26 tumor-bearing male and female mice. BALB/c mice were injected with CT26 tumor cells, and after the tumor was palpable, underwent three cycles of FOLFOX. FOLFOX reduced tumor mass in both sexes. CT26 induced plasma interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and tumor necrosis factor-alpha (TNF-α) in males and females. FOLFOX attenuated the CT26-induced IL-6 and LIF levels in males, but in females FOLFOX alone induced IL-6 and TNF-α, and did not attenuate their CT26 induction. In CT26 males, but not females, total lean and hindlimb mass were negatively associated with IL-6, and FOLFOX disrupted this association. The CT26-induced muscle p-STAT3 was inversely associated with muscle mass in males only and disrupted by FOLFOX. Circulating inflammatory cytokines were associated with body composition changes and functional deficits in CT26 males, but FOLFOX and female sex altered this relationship. Our results provide evidence that the female response to circulating inflammatory cytokines in the CT26 tumor environment, following FOLFOX chemotherapy, differs from that of males, and the physiological ramifications of this regulation warrant further investigation.NEW & NOTEWORTHY The present study demonstrates that in colon tumor-bearing mice, the administration of FOLFOX chemotherapy alters plasma inflammatory cytokines' relationship to tumor mass, body composition, and physical function. Furthermore, sex influences these responses. These findings have implications for mechanistically understanding sex-specific muscle wasting and metabolic complications experienced by patients with colorectal cancer undergoing chemotherapy treatment.

Cancer cachexia is a wasting condition, primarily affecting skeletal muscle, impairing patients' quality of life, prognosis, and survival. The molecular triggers are incompletely defined, but given prior evidence for epigenetic plasticity in muscle, we speculate that dysregulated DNA methylation plays a role in muscle transcriptional alterations mediating cachexia severity. We aimed to describe and integrate the cachexia methylome and transcriptome. We used a time course approach in a mild cachexia model (colon-26, C26) coupled with a severe cachexia genetic model (Apc^Min/+) in both biological sexes to assess the methylome across degrees of cachexia pathology. The muscle methylome and transcriptome were analyzed separately and subsequently integrated using a computational technique to infer epigenetic control of gene expression. Male mice exhibited widespread disruptions to the transcriptome across time points, whereas females were more protected; in severe pathophysiologic phenotypes, the magnitude of change was similar between sexes. A conserved set of inflammation-related genes was dysregulated across cachexia progression and sex, including Osmr, Stat3, and Serpina3n. Epigenetic alterations in both sexes emerged in promoter regions as early as 10 days post-tumor implant in C26, despite a lack of physiologic phenotype and before the transcriptome disruptions. Our integration analysis suggests methylome alterations as a mechanism of cachexia pathophysiology in severe phenotypes. A conserved feature across -omics layers, sexes, and conditions was dysregulated Runx1 and neurodegeneration-related pathways, which may indicate cachexia-mediated denervation. Overall, we provide evidence for the role of epigenetics in cachexia progression and severity and a valuable resource to the cachexia research communities.NEW & NOTEWORTHY Using multi-omics integration, we establish that DNA methylation status likely influences the muscle transcriptome during cancer cachexia, affecting pathways commonly disrupted in cachexia including those associated with neurodegeneration and metabolism. Epigenetic dysregulation occurs early and progresses during the onset and establishment of cancer cachexia, highlighting DNA methylation as a potential therapeutic target to slow or mitigate disease progression.

After myocardial infarction (MI), increased spontaneous sarcoplasmic reticulum (SR)-Ca²⁺ releases depolarize the membrane and trigger action potentials (APs) in cardiac Purkinje cells (Pcells). This abnormal Ca²⁺-activity is involved in ventricular fibrillation. Spontaneous Ca²⁺-transients analysis suggested that intensification of SR-Ca²⁺ uptake accounts for the abnormal SR-Ca²⁺ release in post-MI Pcells. Increased SR-Ca²⁺-pump (SERCA) density, phospholamban (PLB)-dependent Ca²⁺-pump activation, and modification of the pump Ca²⁺-transport properties can mediate an increase in SR-Ca²⁺ uptake. We examined whether Pcells of ischemic hearts show signs of these alterations, hence supporting the hypothesis of post-MI increase in SR-Ca²⁺-uptake. Pcells were prepared from hearts with and without MI in dogs, sheep, pigs, and humans. The distribution of SR-Ca²⁺ pumps and phosphorylated forms of PLB, pPLBSer16 and pPLBThr17, was captured by specific immunofluorescence and confocal microscopy. Protein and transcript levels of sarco/endoplasmic reticulum calcium ATPase isoform 2 (SERCA2) subisoforms were measured in Purkinje fibers and myocardium by Western blot (WB) and reverse transcription quantitative polymerase chain reaction (RT-qPCR), respectively. In normal hearts, Ca²⁺ pumps and PLB antibodies colocalized throughout Pcells. After MI, Ca²⁺ pump staining exhibited larger intensity in peripheral compared with central regions of Pcells. Phosphorylated PLB staining was unchanged, indicating no alteration of the pump-β-adrenergic regulation after MI. Expression of the regular cardiac pump, SERCA2a, was preserved. However, the emergence of another pump, SERCA2b, was found after MI. The addition of SERCA2b to the existing SERCA2a expression increased the total pump density, which was consistent with an augmentation of SR-Ca²⁺-uptake in Pcells after MI. After MI, the peripheral region of Pcells seems to express the SERCA2b pump subisoform, which is consistent with larger pump density and intensification of SR-Ca²⁺ uptake.NEW & NOTEWORTHY A gradient in the density of SR-Ca²⁺ pumps appears from the center to the periphery of Purkinje cells (Pcells) after MI. We found that this post-MI rearrangement could result from the peripheral expression of SERCA2b pump, which is absent in healthy hearts. The additional expression of SERCA2b to the existing cardiac pump SERCA2a, and possibly more efficient Ca²⁺-transport properties of SERCA2b, are consistent with the proarrhythmic elevation of SR-Ca²⁺ uptake previously proposed in Pcells after MI.

Monocytes and regulatory noncoding RNAs play a crucial role in the development of atherosclerosis (ATH). We have previously shown that miR-125b-5p was upregulated in aortic macrophages, and the aim of this paper was to further study the "in vivo" impact of miR-125b-5p in ATH progression. Eight-weeks-old ApoE^-/- mice, fed with a high-fat diet for 14 wk, were treated with a miR-125b-5p mimic, with its specific antagonist (antagomiR-125b), with a control scrambled sequence (control oligonucleotide SC) or with a control vehicle with phosphate-buffered saline (PBS) for 4 wk. Treatment with the miR-125b-5p mimic increased plaque sizes, macrophage infiltration, and NF-κB activation compared to PBS control, independently of cholesterol levels. In contrast, treatment with a specific antagomir produced opposite effects and increased the number of M2 macrophages. Finally, the miR-125b-5p mimic was found to reduce expression of the chemokine receptor CCR7 in the human monocyte cell line THP-1 cells, and the mouse macrophage-like cell line RAW264.7 cells, as well as in the aortas and livers of mice, whereas the antagomiR-125b increased CCR7 expression. Reduced CCR7 expression was also observed in the aorta of patients with coronary artery disease. miR-125b-5p mimic increased inflammation and ATH progression. Targeting miR-125b-5p with a specific antagomir reduced plaque size and macrophage infiltration and increased expression of the chemokine receptor CCR7. These results support a role for miR-125b-5p in the upregulation of CCR7 expression and monocyte trafficking, thus restricting vascular inflammation in ATH progression.NEW & NOTEWORTHY Our study investigates the role of inflammation and monocyte trafficking in atherosclerosis (ATH). We show that miR-125b-5p increases plaque inflammation and downregulates CCR7. Targeting miR-125b-5p with a specific antagomir restores CCR7 expression, enhances macrophage migration, and reduces both the inflammation and plaque size. The miR-125b-5p/CCR7 axis in ATH progression was further validated in a cohort of patients, suggesting that modulating this pathway may offer a novel therapeutic strategy.

It remains unclear how excess adipose tissue in obesity leads to inflammation, insulin resistance, and other comorbidities. Extracellular nucleosides can induce inflammation through the activation of immune cell toll-like and purinergic receptors. The present study quantified nucleoside release from adipocytes and adipose tissue. Cultured mouse adipocytes released many nucleosides used in RNA/DNA. Adipose tissue from obese mice released more nucleosides than that from control nonobese mice ex vivo and had higher interstitial fluid concentrations in vivo. Consistent with the mouse study, human adipose tissue also showed significant release of adenosine/deoxyadenosine, guanosine/deoxyguanosine, and uridine ex vivo. Adipocytes release nucleosides in part through the equilibrative nucleoside transporter 1, though other pathways also appear to contribute to extracellular nucleoside concentrations. Extracellular nucleosides induce adipose tissue expression of inflammatory cytokines Tnfα, Il6, and Il1β. These data uncover a previously unknown phenomenon of adipocyte release of nucleosides, which contribute to adipose tissue inflammation in obesity.NEW & NOTEWORTHY Adipose tissue inflammation contributes to the morbidity and mortality of obesity. Adipocytes are known to release uridine and adenosine, but information on other nucleosides is lacking. As nucleosides can induce inflammation, we characterized nucleoside release from mouse and human adipose tissue. Adipose tissue released adenosine/deoxyadenosine, guanosine/deoxyguanosine, and uridine ex vivo. Nucleoside secretion was associated with adipose tissue expression of inflammatory cytokines. This represents a new mechanism by which obese adipose tissue may develop inflammation.