Disruption Of Calcium Homeostasis Research Articles

Nitric oxide: Potential therapeutic target in Heat Stress-induced Multiple Organ Dysfunction.

As climate change intensifies, urgent action is needed to address global warming and its associated health risks, particularly in vulnerable regions. Rising global temperature and increasing frequency of heatwaves present a hidden health risk, disrupting the body's temperature regulation and leading to severe consequences such as heat stress-induced multiple organ dysfunction (HS-MOD). Multiple organ injury triggered by heat stress involves complex molecular pathways such as nitric oxide dysregulation, inflammation, oxidative stress, mitochondrial dysfunction, calcium homeostasis disruption, and autophagy impairment that contribute to cellular damage. Understanding these molecular pathways is crucial for developing targeted therapeutic interventions to alleviate the impact of heat stress (HS). As we explore numerous therapeutic strategies, a remarkable molecule captures our attention: nitric oxide (NO). This colorless gas, mainly produced by nitric oxide synthase (NOS) enzymes, plays crucial roles in various body functions. From promoting vasodilation and neurotransmission to regulating the immune response, platelet function, cell signaling, and reproductive health, NO stands out for its versatility. Exploring it as a promising treatment for heat stress-induced multiple organ injury highlights its distinctive features in the journey towards effective therapeutic interventions. This involves exploring both pharmacological avenues, considering the use of NO donors and antioxidants, and non-pharmacological strategies, such as adopting nitrate-rich diets and engaging in exercise regimens. This review highlights the concept of heat stress, the molecular framework of the disease, and treatment options based upon some new interventions.

Long-Term Neurotoxic Effects and Alzheimer's Disease Risk of Early EHDPP Exposure in Zebrafish: Insights from Molecular Mechanisms to Adult Pathology.

2-Ethylhexyl diphenyl phosphate (EHDPP), ubiquitously monitored in environmental media, is highly bioaccumulative and may pose long-term risks, even after short-term exposure. In this investigation, larval zebrafish were exposed to 0.05, 0.5, and 5.0 μg/L EHDPP from 4 to 120 h postfertilization (hpf) to examine the long-term neurotoxicity effects of early exposure. Exposure to 5.0 μg/L EHDPP yielded hyperactive locomotor behavior, which was characterized by increased swimming speed, larger turning angles, and heightened sensitivity to light-dark stimulation. The predicted targets of EHDPP (top 100 potential macromolecules) were primarily associated with brain diseases like Alzheimer's disease (AD). Comparisons of differentially expressed genes (DEGs) from AD patients (GSE48350) and RNA-seq data from EHDPP-exposed zebrafish confirmed consistently abnormal regulatory pathways. EHDPP's interaction with M1 and M5 muscarinic acetylcholine receptors likely disrupted calcium homeostasis, leading to mitochondrial dysfunction and neurotransmitter imbalance as well as abnormal locomotor behavior. Especially, 5.0 μg/L EHDPP exposure during early development (4-120 hpf) triggered early- and midstage AD-like symptoms in adulthood (180 dpf), characterized by cognitive confusion, aggression, blood-brain barrier disruption, and mitochondrial damage in brains. These findings provide deep insights into the long-term neurotoxicity effects and Alzheimer's disease risks of early EHDPP exposure at extremely low dosages.

Resmethrin disrupts mitochondria-associated membranes and activates endoplasmic reticulum stress, leading to proliferation inhibition in cultured mouse Leydig and Sertoli cells

Resmethrin, a pyrethroid pesticide used to control insects, is toxic to non-target organisms and other mammals. However, little is known about the reproductive toxicity of resmethrin in the testes, or its mechanism of toxicity. In this study, we investigated the testicular toxicity of resmethrin on mouse Leydig (TM3) and Sertoli (TM4) cells, focusing on the mitochondria and endoplasmic reticulum (ER). We found that resmethrin inhibited proliferation and cell cycle progression and disrupted mitochondrial membrane potential (MMP; ΔΨ) in TM3 and TM4 cells. In particular, resmethrin exposure significantly reduced the expression of mitochondria-associated membranes (MAMs) proteins, such as Vapb, Vdac, and Grp75, in both cell lines. Resmethrin also disrupts calcium homeostasis in the mitochondrial matrix and cytoplasm. In addition, resmethrin activates oxidative stress-mediated ER stress signals. Finally, we confirmed that 4-PBA, an ER stress inhibitor, restored the growth of TM3 and TM4 cells, which was decreased by resmethrin. Therefore, we confirmed that resmethrin hampered MAMs and activated ER stress, thus suppressing TM3 and TM4 cell proliferation.

Adrenomedullin as a New Prosperous Biomarker in Infections: Current and Future Perspectives

Adrenomedullin has emerged as a promising biomarker in the field of viral diseases. Numerous studies have demonstrated its potential in assessing disease severity, predicting clinical outcomes, and monitoring treatment response. Adrenomedullin (AM) is a multifaceted peptide implicated in vasodilation, hormone secretion, antimicrobial defense, cellular growth, angiogenesis, and, importantly, chronic pain. AM and related peptides interface with cytoskeletal proteins within neuronal contexts, influencing microtubule dynamics. AM has primarily been utilized in diagnosing diseases of bacterial origin, including sepsis. Nevertheless, there are reports suggesting its utility in diseases of viral origin, and this is the focus of the present study. Furthermore, adrenomedullin has been shown to be elevated in various viral infections, suggesting its role in immune response modulation. Furthermore, AM may contribute to neuronal dysfunction through mechanisms involving immune and inflammatory responses, apoptosis, and disruptions in calcium homeostasis. This review aims to consolidate current knowledge regarding AM and its potential implications in viral diseases, elucidating its diverse roles in neurological pathophysiology. This review highlights the growing importance of adrenomedullin as a biomarker in viral diseases and the need for further functional studies to understand the underlying mechanisms involved.

Regulatory Peptide Pro-Gly-Pro Accelerates Neuroregeneration of Primary Neuroglial Culture after Mechanical Injury in Scratch Test

The scratch test is used as an experimental in vitro model of mechanical damage to primary neuronal cultures to study the mechanisms of cell death in damaged areas. The involvement of NMDA receptors in processes leading to delayed neuronal death, due to calcium dysregulation and synchronous mitochondrial depolarization, has been previously demonstrated. In this study, we explored the neuroregenerative potential of Pro-Gly-Pro (PGP)—an endogenous regulatory peptide with neuroprotective and anti-inflammatory properties and a mild chemoattractant effect. Mechanical injury to the primary neuroglial culture in the form of a scratch caused acute disruption of calcium homeostasis and mitochondrial functions. This was accompanied by neuronal death alongside changes in the profile of neuronal markers (BDNF, NSE and GFAP). In another series of experiments, under subtoxic doses of glutamate (Glu, 33 μM), delayed changes in [Ca2+]i and ΔΨm, i.e., several days after scratch application, were more pronounced in cells in damaged neuroglial cultures. The percentage of cells that restored the initial level of [Ca2+]i (p < 0.05) and the rate of recovery of ΔΨm (p < 0.01) were decreased compared with undamaged cells. Prophylactic application of PGP (100 μM, once) prevented the increase in [Ca2+]i and the sharp drop in mitochondrial potential [ΔΨm] at the time of scratching. Treatment with PGP (30 μM, three or six days) reduced the delayed Glu-induced disturbances in calcium homeostasis and cell death. In the post-glutamate period, the surviving neurons more effectively restored the initial levels of [Ca2+]i (p < 0.001) and Ψm (p < 0.0001). PGP also increased intracellular levels of BDNF and reduced extracellular NSE. In the context of the peptide’s therapeutic effect, the recovery of the damaged neuronal network occurred faster due to reduced astrogliosis and increased migration of neurons to the scratch area. Thus, the peptide PGP has a neuroprotective effect, increasing the survival of neuroglial cells after mechanical trauma in vitro by reducing cellular calcium overload and preventing mitochondrial dysfunction. Additionally, the tripeptide limits the post-traumatic consequences of mechanical damage: it reduces astrogliosis and promotes neuronal regeneration.

The role of calcium homeostasis in modulating the immune response in cancer and infectious diseases

Calcium homeostasis is a pivotal determinant of physiological processes, particularly in cellular signaling and immune system regulation. This balance is crucial for modulating immune responses in the context of both infectious and oncological diseases. Disruptions in calcium homeostasis have been shown to influence disease progression, immune efficacy, and treatment outcomes. Our study investigates the critical role of calcium homeostasis in shaping the immune response to cancer and infectious diseases through a comprehensive literature review. The electronic databases Scopus, Google Scholar, and PubMed were utilized to gather relevant studies, identified using key terms such as "calcium homeostasis," "immune response," "cancer," and "infectious diseases." Emerging evidence underscores that calcium levels directly impact immune cell function, including the activation of immune effector cells, cytokine production, and the orchestration of the overall immune response. These processes are critical to the body's ability to combat infections and malignancies. Aberrant calcium signaling may lead to compromised immune defense mechanisms, negatively affecting the outcomes of therapeutic interventions. In cancer, for example, altered calcium homeostasis can suppress immune surveillance, while in infectious diseases, it can hinder the immune system's capacity to clear pathogens. Our review highlights that the pathophysiology of both cancer and infectious diseases is tightly interwoven with calcium regulation, suggesting a promising avenue for therapeutic targeting. Modulating calcium homeostasis may enhance immune functionality, thereby improving treatment efficacy. By restoring calcium balance, novel therapeutic approaches could be developed to optimize immune responses and bolster clinical outcomes across a range of diseases. Further research is warranted to elucidate the precise molecular mechanisms linking calcium homeostasis and immune regulation, with the goal of refining future therapeutic strategies. Maintaining calcium equilibrium is thus essential for the advancement of effective treatments in both cancer and infectious disease contexts.

Resmethrin induces implantation failure by disrupting calcium homeostasis and forcing mitochondrial defects in porcine trophectoderm and uterine luminal epithelial cells

Resmethrin, a type I pyrethroid insecticide, is frequently used globally in residential and farmland areas to control pests. Owing to the repeated administration of resmethrin, and particularly because of its lipophilic nature, residues have been detected in various environments, crops, and livestock. Previous studies have shown the adverse effects of resmethrin, including neurotoxicity and hepatotoxicity. However, the toxic effects of resmethrin on the female reproductive system have rarely been investigated. In the present study, we used two cell types, porcine trophectoderm (pTr) and porcine uterine luminal epithelial (pLE) cells, to examine the toxic effects of resmethrin on implantation and its mechanisms. Our study showed that resmethrin exposure induced apoptosis and inhibited cell cycle progression, thereby reducing the viability of both cell types. In addition, calcium homeostasis was disrupted following resmethrin treatment, and disrupted calcium homeostasis impaired the mitochondrial membrane potential and mitochondrial respiration. In addition to mitochondrial dysfunction, GRP75 and ER stress–related proteins were upregulated. Furthermore, the AKT and MAPK cascades were altered, and reactive oxygen species production and inflammation occurred after resmethrin treatment. Ultimately, through various mechanisms, resmethrin decreased the migratory abilities, and it could diminish the crosstalk between the two cell lines and lower the probability of successful implantation. Overall, we demonstrated that resmethrin interfered with the implantation process by triggering various toxic mechanisms. This study presents, for the first time, evidence regarding the mechanisms through which resmethrin exerts toxic effects on the female reproductive system, thereby raising awareness regarding the potential implications of its widespread use.

Focus on the role of calcium signaling in ferroptosis: a potential therapeutic strategy for sepsis-induced acute lung injury.

By engaging in redox processes, ferroptosis plays a crucial role in sepsis-induced acute lung injury (ALI). Although iron stimulates calcium signaling through the stimulation of redox-sensitive calcium pathways, the function of calcium signals in the physiological process of ferroptosis in septic ALI remains unidentified. Iron homeostasis disequilibrium in ferroptosis is frequently accompanied by aberrant calcium signaling. Intracellular calcium overflow can be a symptom of dysregulation of the cellular redox state, which is characterized by iron overload during the early phase of ferroptosis. This can lead to disruptions in calcium homeostasis and calcium signaling. The mechanisms controlling iron homeostasis and ferroptosis are reviewed here, along with their significance in sepsis-induced acute lung injury, and the potential role of calcium signaling in these processes is clarified. We propose that the development of septic acute lung injury is a combined process involving the bidirectional interaction between iron homeostasis and calcium signaling. Our goal is to raise awareness about the pathophysiology of sepsis-induced acute lung injury and investigate the relationship between these mechanisms and ferroptosis. We also aimed to develop calcium-antagonistic therapies that target ferroptosis in septic ALI and improve the quality of survival for patients suffering from acute lung injury.

New insight into primary hyperparathyroidism using untargeted metabolomics

Primary Hyperparathyroidism (PHPT) is characterized by excessive parathormone (PTH) secretion and disrupted calcium homeostasis. Untargeted metabolomics offers a valuable approach to understanding the complex metabolic alterations associated with different diseases, including PHPT. Plasma untargeted metabolomics was applied to investigate the metabolic profiles of PHPT patients compared to a control group. Two complementary liquid-phase separation techniques were employed to comprehensively explore the metabolic landscape in this retrospective, single-center study. The study comprised 28 female patients diagnosed following the current guidelines of PHPT diagnosis and a group of 30 healthy females as a control group. To evaluate their association with PHPT, we identified changes in plasma metabolic profiles in patients with PHPT compared to the control group. The primary outcome measure included detecting plasma metabolites and discriminating PHPT patients from controls. The study unveiled specific metabolic imbalances that may link l-amino acids with peptic ulcer disease, gamma-glutamyls with oxidative stress, and asymmetric dimethylarginine (ADMA) with cardiovascular complications. Several metabolites, such as gamma-glutamyls, caffeine, sex hormones, carnitine, sphingosine-1-phosphate (S-1-P), and steroids, were connected with reduced bone mineral density (BMD). Metabolic profiling identified distinct metabolic patterns between patients with PHPT and healthy controls. These findings provided valuable insights into the pathophysiology of PHPT.

Impact of oxytosis on the cross-talk of mTORC with mitochondrial proteins in drug-resistant cancer stem cells.

By delivering the environmental inputs to transport nutrients and growth factors, Mechanistic Target of Rapamycin (mTOR) plays a significant role in the growth and metabolism of eukaryotic cells through the regulation of numerous elementary cellular processes such as autophagy, protein synthesis, via translation of mitochondrial protein transcription factor A mitochondrial, mitochondrial ribosomal proteins, and mitochondrial respiratory complexes I &V that are encoded in the nucleus with the help of translation initiation factor 4E-BP. These mitochondrial proteins are involved in cell signaling to regulate proper cell growth, proliferation, and death which are essential for tumor growth and proliferation. This suggests that tumor cells are dependent on mTORC1 for various metabolic pathways. However, this crucial regulator is activated and regulated by calcium homeostasis. Mounting evidence suggests the role of calcium ions in regulating mitochondrial enzymes and proteins. Hence, disrupting calcium homeostasis leads to calcium-dependent cell death called "Oxytosis" through hampering the expression of various mitochondrial proteins. "Oxytosis" is a novel non-apoptotic cell death characterized by glutamate cytotoxicity and ferritin degradation. The present review focuses on the crosstalk between mTORC1 and mitochondrial proteins in the cancer pathophysiology and the impact of calcium ions on disrupting mTORC1 leading to the induction of "Oxytosis."

Interneurons in the CA1 stratum oriens expressing αTTP may play a role in the delayed-ageing Pol μ mouse model

Neurodegeneration associated with ageing is closely linked to oxidative stress (OS) and disrupted calcium homeostasis. Some areas of the brain, like the hippocampus – particularly the CA1 region – have shown a high susceptibility to age-related changes, displaying early signs of pathology and neuronal loss. Antioxidants such as α-tocopherol (αT) have been effective in mitigating the impact of OS during ageing. αT homeostasis is primarily regulated by the α-tocopherol transfer protein (αTTP), which is widely distributed throughout the brain – where it plays a crucial role in maintaining αT levels within neuronal cells.This study investigates the distribution of αTTP in the hippocampus of 4- and 24-month-old Pol μ knockout mice (Pol μ−/−), a delayed-ageing model, and the wild type (Pol μ+/+). We also examine the colocalisation in the stratum oriens (st.or) of CA1 region with the primary interneuron populations expressing calcium-binding proteins (CBPs) (calbindin (CB), parvalbumin (PV), and calretinin (CR)). Our findings reveal that αTTP immunoreactivity (-IR) in the st.or of Pol μ mice is significantly reduced. The density of PV-expressing interneurons (INs) increased in aged mice in both Pol μ genotypes (Pol μ−/− and Pol μ+/+), although the density of PV-positive INs was lower in the aged Pol μ−/− mice compared to wild-type mice. By contrast, CR- and CB-positive INs in Pol μ mice remained unchanged during ageing.Furthermore, double immunohistochemistry reveals the colocalisation of αTTP with CBPs in INs of the CA1 st.or. Our study also shows that the PV/αTTP-positive IN population remains unchanged in all groups. A significant decrease of CB/αTTP-positive INs in young Pol μ−/− mice has been detected, as well as a significant increase in CR/αTTP-IR in older Pol μ−/− animals. These results suggest that the differential expression of αTTP and CBPs could have a crucial effect in aiding the survival and maintenance of the different IN populations in the CA1 st.or, and their coexpression could contribute to the enhancement of their resistance to OS-related damage and neurodegeneration associated with ageing.

ML218 modulates calcium binding protein, oxidative stress, and inflammation during ischemia-reperfusion brain injury in mice

Cerebral ischemia disrupts calcium homeostasis in the brain causing excitotoxicity, oxidative stress, inflammation, and neuronal cell apoptosis. During ischemic conditions, T-type calcium channel channels contribute to increase in intracellular calcium ions in both neurons and glial cells therefore, the current study hypothesizes the antagonism of these channels using ML218, a novel specific T-Type inhibitor in experimental model of cerebral ischemia-reperfusion (CI/R) brain injury. CI/R injury was induced in Swiss Albino mice by occlusion of common carotid arteries followed by reperfusion. Animals were assessed for learning and memory (MWM), motor coordination (Rota rod), neurological function (neurological deficit score), cerebral infarction, edema, and histopathological alterations. Biochemical assessments were made for calcium binding proteins (Calmodulin- CaM, calcium/calmodulin-dependent protein kinase II-CaMKII, S100B), oxidative stress (4-hydroxy 2-nonenal-4-HNE, glutathione-GSH, inflammation (nuclear factor kappa-light-chain-enhancer of activated B-p65-NF-kB, tumor necrosis factor-TNF-α, interleukin-IL-10) inducible nitric oxide synthase (iNOS) levels, and acetylcholinesterase activity (AChE) in brain supernatants. Furthermore, serum levels of NF-kB, iNOS, and S100B were also assessed. CI/R animals showed impairment in learning, memory, motor coordination, and neurological function along with increase in cerebral infarction, edema, and histopathological alterations. Furthermore, increase in brain calcium binding proteins, oxidative stress, inflammation, and AChE activity along with serum NF-kB, iNOS, and S100B levels were recorded in CI/R animals. Administration of ML218 (5 mg/kg and 10 mg/kg; i.p.) was observed to recuperate CI/R induced impairments in behavioral, biochemical, and histopathological analysis. Hence, it may be concluded that ML218 mediates neuroprotection during CI/R via decreasing brain and serum calcium binding proteins, inflammation, iNOS, and oxidative stress markers.

Effects of Atorvastatin and Simvastatin on the Bioenergetic Function of Isolated Rat Brain Mitochondria.

Little is known about the effects of statins, which are cholesterol-lowering drugs, on the bioenergetic functions of mitochondria in the brain. This study aimed to elucidate the direct effects of atorvastatin and simvastatin on the bioenergetics of isolated rat brain mitochondria by measuring the statin-induced changes in respiratory chain activity, ATP synthesis efficiency, and the production of reactive oxygen species (ROS). Our results in isolated brain mitochondria are the first to demonstrate that atorvastatin and simvastatin dose-dependently significantly inhibit the activity of the mitochondrial respiratory chain, resulting in a decreased respiratory rate, a decreased membrane potential, and increased ROS formation. Moreover, the tested statins reduced mitochondrial coupling parameters, the ADP/O ratio, the respiratory control ratio, and thus, the oxidative phosphorylation efficiency in brain mitochondria. Among the oxidative phosphorylation complexes, statin-induced mitochondrial impairment concerned complex I, complex III, and ATP synthase activity. The calcium-containing atorvastatin had a significantly more substantial effect on isolated brain mitochondria than simvastatin. The higher inhibitory effect of atorvastatin was dependent on calcium ions, which may lead to the disruption of calcium homeostasis in mitochondria. These findings suggest that while statins are effective in their primary role as cholesterol-lowering agents, their use may impair mitochondrial function, which may have consequences for brain health, particularly when mitochondrial energy efficiency is critical.

Abstract Mo052: Electrocardiographic behavior, arrhythmias, and mortality in two calcium management strategies (cytoplasmic and mitochondrial) in hearts under ischemia.

Background: The disruption of calcium homeostasis in ischemic hearts is determinant for triggering the arrhythmic phenomena and death. Interventions that act on calcium levels in cytoplasm and mitochondria might interrupt or minimize these outcomes. Trisulfate disaccharide (TD) acts by accelerating the sodium-calcium exchanger, decreasing cytosolic calcium levels. Ruthenium red (RuR) is a mitochondrial uniporter inhibitor that blocks calcium influx into mitochondria. Both agents can be useful in calcium overload elicited by myocardial ischemia (MI), modifying electrocardiographic (EKG) parameters that predict arrhythmia, arrhythmic phenomena, and cell death. Objectives: To compare the behavior of Tp-Te and QTc EKG intervals, arrhythmia rates, and mortality in ischemic hearts under the action of TD and RuR. Materials and Methods: Adult Wistar rats (n=24) were divided in 3 groups, i.e, Control: MI with no treatment (n=8), TD: MI treated with TD 0.2 mg/kg IV (n=8), and RuR:MI treated with RuR 1 mg/kg IV (n=8). Rats were monitored by EKG and submitted to surgical MI by ligation of anterior descending artery during 10 minutes followed by reperfusion thereafter. The Tp-Te and QT intervals were analyzed before and at 10 minutes of ischemia and 10 minutes after the onset of reperfusion. The incidence of arrhythmias and mortality were determined throughout the recording time. Results: The Tp-Te and QTc intervals increased during ischemia in all groups (Control, TD and RuR), which were normalized after 10 minutes reperfusion only in TD group. The observed arrhythmias (atrioventricular block, ventricular tachycardia, and torsade of pointes) had a higher incidence in the control group and the lower incidences, with statistically significant differences, were achieved in TD and RuR groups, whose incidence was similar in these both groups. Sustained arrhythmias led to a 50% mortality in the control group and 25% in RuR group. No mortality in TD group was observed. Conclusion: The strategy of decreasing cytosolic calcium levels by the action of TD has proved to be more effective than the blockade of mitochondrial calcium uptake by RuR, with further normalization of EKG parameters predictors of mortality, and absence of sustained arrhythmias and mortality, suggesting that the management of cytosolic calcium levels is more effective than only the management of mitochondrial calcium in MI model.

Abstract Mo074: Overexpression of IPP2 Impairs Intracellular Calcium Handling, Leading to Arrhythmogenic Events

Cardiac arrhythmias, which are disruptions in the heart's electrical activities, critically affect the ventricular conduction system, impairing efficient blood circulation. These disturbances result in irregular heartbeats, contributing to patient mortality or causing harm to distant organs via embolic events. Given the severe implications, a profound understanding of the molecular mechanisms driving arrhythmia is crucial for devising specific treatments. This study unveils a pioneering link between the overexpression of IPP2 (Protein Phosphatase 1 Regulatory Inhibitor Subunit 2), driven by the Myh6 promoter (termed TgIPP2), and the onset of age-dependent cardiac arrhythmias. The electrical abnormalities observed in TgIPP2 overexpressing mice include a spectrum of dysfunctions such as axis deviations, elongated QRS and PR intervals, absence of P waves, AV dissociation, ventricular tachyarrhythmia, and heightened T waves. Investigating the pathophysiology behind these electrical anomalies, we subjected young adult mice to catecholamine challenges at low doses and conducted surface electrocardiogram (EKG) monitoring. TgIPP2 mice demonstrated a notable increase in arrhythmogenic episode frequency and duration following 0.2 mg/kg isoproterenol injection compared to their control counterparts. Through a protein phosphorylation analysis, we identified a key regulator of the ryanodine receptor, which modulates calcium release from the sarcoplasmic reticulum, correlating with the extended PR intervals and the delayed peaking of T waves. Therapeutic trials employing RyR blockers, specifically dantrolene, successfully normalized the erratic cardiac rhythms in aged TgIPP2 mice. However, beta blockers or L-type calcium channel blockers induced sudden cardiac death in this model. The study reveals that IPP2-induced aberrant phosphorylation disrupts calcium homeostasis, leading to arrhythmias. In conclusion, our research marks a significant advancement in understanding arrhythmogenic mechanisms, demonstrating that IPP2 overexpression directly triggers arrhythmia, particularly affecting the atrioventricular (AV) node, atria, and ventricles. The discovery that aberrant phosphorylation, especially of the RyR regulator, plays a pivotal role in initiating cardiac arrhythmias opens new pathways for targeted anti-arrhythmic therapies.

Identification and validation of calcium extrusion-related genes prognostic signature in colon adenocarcinoma.

Disruptions in calcium homeostasis are associated with a wide range of diseases, and play a pivotal role in the development of cancer. However, the construction of prognostic models using calcium extrusion-related genes in colon adenocarcinoma (COAD) has not been well studied. We aimed to identify whether calcium extrusion-related genes serve as a potential prognostic biomarker in the COAD progression. We constructed a prognostic model based on the expression of calcium extrusion-related genes (SLC8A1, SLC8A2, SLC8A3, SLC8B1, SLC24A2, SLC24A3 and SLC24A4) in COAD. Subsequently, we evaluated the associations between the risk score calculated by calcium extrusion-related genes and mutation signature, immune cell infiltration, and immune checkpoint molecules. Then we calculated the immune score, stromal score, tumor purity and estimate score using the Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) algorithm. The response to immunotherapy was assessed using tumor immune dysfunction and exclusion (TIDE). Finally, colorectal cancer cells migration, growth and colony formation assays were performed in RKO cells with the overexpression or knockdown SLC8A3, SLC24A2, SLC24A3, or SLC24A4. We found that patients with high risk score of calcium extrusion-related genes tend to have a poorer prognosis than those in the low-risk group. Additionally, patients in high-risk group had higher rates of KRAS mutations and lower MUC16 mutations, implying a strong correlation between KRAS and MUC16 mutations and calcium homeostasis in COAD. Moreover, the high-risk group showed a higher infiltration of regulatory T cells (Tregs) in the tumor microenvironment. Finally, our study identified two previously unreported model genes (SLC8A3 and SLC24A4) that contribute to the growth and migration of colorectal cancer RKO cells. Altogether, we developed a prognostic risk model for predicting the prognosis of COAD patients based on the expression profiles of calcium extrusion-related genes, Furthermore, we validated two previously unreported tumor suppressor genes (SLC8A3 and SLC24A4) involved in colorectal cancer progression.

Impact of DEHP on mitochondria-associated endoplasmic reticulum membranes and reproductive toxicity in ovary

Di(2-ethylhexyl) phthalate (DEHP) is a widely recognized environmental endocrine disruptor that potentially impacts female reproductive function, although the specific mechanisms leading to such impairment remain unclear. A growing body of research has revealed that the endoplasmic reticulum and mitochondrial function significantly influence oocyte quality. The structure of mitochondria-associated endoplasmic reticulum membranes (MAMs) is crucial for facilitating the exchange of Ca2+, lipids, and metabolites. This study aimed to investigate the alterations in the composition and function of MAMs after DEHP exposure and to elucidate the underlying mechanisms of ovarian toxicity. The female mice were exposed to DEHP at doses of 5 and 500 mg/kg/day for one month. The results revealed that DEHP exposure led to reduced serum anti-Müllerian hormone levels and increased atretic follicles in mice. DEHP induced endoplasmic reticulum stress and disrupted calcium homeostasis in oocytes. Furthermore, DEHP impaired the mitochondrial function of oocytes and reduced their membrane potential, and promoting apoptosis. Similar results were observed in human granulosa cells after exposure to mono-(2-ethylhexyl) phthalate (MEHP, metabolites of DEHP) in vitro. Proteomic analysis and transmission electron microscopy revealed modifications in the functional proteins and structure of the MAMs, and the suppression of oxidative phosphorylation pathways. The findings of this investigation provide a new perspective on the mechanism underlying the reproductive toxicity of DEHP in females.

DIPG-62. REPURPOSING OF ANTIPSYCHOTIC TRIFLUOPERAZINE FOR INHIBITING MITOCHONDRIAL FUNCTION IN DIFFUSE MIDLINE GLIOMA

Abstract BACKGROUND Diffuse Midline Gliomas (DMGs) present formidable challenges in neuro-oncology, prompting the exploration of innovative therapeutic strategies. Repurposing approved drugs, particularly those exhibiting multifaceted effects, holds promise for addressing these challenges efficiently. In this study, we investigate the potential of trifluoperazine (TFP), an antipsychotic medication, with a specific focus on its mitochondrial-targeted actions in DMGs. METHODS TFP, a phenothiazine derivative, displayed robust in vitro anticancer activity against DMGs. Our investigation explored the molecular mechanisms underlying TFP’s interaction with mitochondria, emphasizing its influence on mitochondrial function, membrane potential, and reactive oxygen species (ROS) production. TFP is well known to induce irreversible Ca2+ release from intracellular stores by directly interacting with calmodulin 2 (CaM2) at the inositol triphosphate receptor (IP3R), leading to IP3R opening. In DMGs, intracellular Ca2+ plays a pivotal role in gene expression, cell motility, differentiation, and survival. TFP disrupts calcium homeostasis by elevating intracellular Ca2+ concentration, thereby inhibiting DMG invasion and growth. DMG cell lines, exhibiting heightened CaM2 expression compared to control healthy astrocyte cells, display increased sensitivity to TFP. RESULTS Remarkably, mitochondrial homeostasis was seriously affected by TFP, and a loss of mitochondrial membrane potential, ROS overproduction and fragmentation of mitochondrial network was observed. This mitochondrial stress, coupled with ER stress, activated the integrated stress response. We demonstrated that TFP induces cell death triggered by a poor ATP content, observed in TFP-treated cells as a consequence of a dramatic decrease in OXPHOS metabolism due to mitochondrial stress. CONCLUSIONS Our findings underscore TFP’s potential as a targeted therapeutic agent against DMGs, offering a better understanding of its impact on mitochondrial and intracellular signaling pathways. As the mitochondrial landscape remains critical in DMG biology, the observed mitochondrial damage-induced oxidative stress provides valuable insights for future investigations into the clinical application of TFP in neuro-oncology.

Visnagin: A novel cardioprotective agent against anthracycline toxicity (Review).

Doxorubicin (DOX), a cornerstone of cancer chemotherapy, is marred by its dose-dependent cardiotoxicity, leading to cardiomyopathy and heart failure. The epidemiology of DOX-related cardiotoxicity highlights its cumulative, progressive nature, with a significant impact on the health of patients. The pathophysiological mechanisms involve mitochondrial dysfunction, oxidative stress and disrupted calcium homeostasis in cardiomyocytes. Despite the search for effective cardioprotective strategies, current treatments offer limited efficacy. Visnagin emerges as a potential solution, known for its vasodilatory and anti-inflammatory properties, and recent studies suggest its cardioprotective efficacy against DOX-induced cardiotoxicity through mitochondrial protection, the modulation of key signaling pathways and the inhibition of apoptosis. The present review aimed to provide a comprehensive overview of the mechanisms of action of visnagin, as well as to provide experimental evidence, and potential integration into cancer treatment regimens, highlighting its promise as a novel therapeutic agent for managing cardiotoxicity in patients undergoing anthracycline chemotherapy.

Inhibition of TBL1 cleavage alleviates doxorubicin-induced cardiomyocytes death by regulating the Wnt/β-catenin signal pathway.

Doxorubicin (DOX) is a widely used anthracycline anticancer agent; however, its irreversible effects on the heart can result in DOX-induced cardiotoxicity (DICT) after cancer treatment. Unfortunately, the pathophysiology of DICT has not yet been fully elucidated, and there are no effective strategies for its prevention or treatment. In this investigation, the novel role of transducin beta-like protein 1 (TBL1) in developing and regulating DICT was explored. We observed a reduction in TBL1 protein expression levels as well as cleavage events in the transplanted cardiac tissues of patients diagnosed with Dilated Cardiomyopathy and DICT. It was revealed that DOX selectively induces TBL1 cleavage at caspase-3 preferred sites-D125, D136, and D215. Interestingly, overexpression of the uncleaved TBL1 mutant (TBL1uclv) variant reduced apoptosis, effectively preventing DOX-induced cell death. We confirmed that cleaved TBL1 cannot form a complex with β-catenin. As a result, Wnt reporter activity and Wnt target gene expression collectively indicate a decrease in Wnt/β-catenin signalling, leading to DICT progression. Furthermore, the cleaved TBL1 triggered DOX-induced abnormal electrophysiological features and disrupted calcium homeostasis. However, these effects were improved in TBL1uclv-overexpressing human-induced pluripotent stem cell-derived cardiomyocytes. Finally, in a DICT mouse model, TBL1uclv overexpression inhibited the DICT-induced reduction of cardiac contractility and collagen accumulation, ultimately protecting cardiomyocytes from cell death. Our findings reveal that the inhibition of TBL1 cleavage not only mitigates apoptosis but also enhances cardiomyocyte function, even in the context of DOX administration. Consequently, this study's results suggest that inhibiting TBL1 cleavage may be a novel strategy to ameliorate DICT.