Search Results (104)

Chloride, long considered a passive extracellular anion, has emerged as a key determinant in the pathophysiology and management of heart failure (HF) and cardiorenal syndrome. In contrast to sodium, which primarily reflects water balance and vasopressin activity, chloride exerts broader effects on neurohormonal activation, acid–base regulation, renal tubular function, and diuretic responsiveness. Its interaction with With-no-Lysine (WNK) kinases and chloride-sensitive transporters underscores its pivotal role in electrolyte and volume homeostasis. Hypochloremia, frequently observed in HF patients treated with loop diuretics, is independently associated with adverse outcomes, diuretic resistance, and arrhythmic risk. Conversely, hyperchloremia—often iatrogenic—may contribute to renal vasoconstriction and hyperchloremic metabolic acidosis. Experimental data also implicate chloride dysregulation in myocardial electrical disturbances and an increased risk of sudden cardiac death. Despite mounting evidence of its clinical importance, serum chloride remains underappreciated in contemporary risk assessment models and treatment algorithms. This review synthesizes emerging evidence on chloride’s role in HF, explores its diagnostic and therapeutic implications, and advocates for its integration into individualized care strategies. Future studies should aim to prospectively validate these associations, evaluate chloride-guided therapeutic interventions, and assess whether incorporating chloride into prognostic models can improve risk stratification and outcomes in patients with heart failure and cardiorenal syndrome. Full article

The recently identified proton-activated chloride (PAC) channel is ubiquitously expressed, and it regulates several proton-sensitive physiological and pathophysiological processes. While the PAC channel is activated by strong acids due to the binding of protons to extracellular binding sites, here, we describe the way in which weak acids inhibit the PAC channel by a mechanism involving a distinct extracellular binding site. Whole-cell patch clamp was performed on wildtype HEK293T cells, PAC-knockout HEK293 cells expressing human (h)PAC mutant constructs, and on hiPSC-derived cardiomyocytes. Proton-induced cytotoxicity was examined in HEK293T cells. Acetic acid inhibited endogenous PAC channels in HEK 293T cells in a reversible, concentration-dependent, and pH-dependent manner. The inhibition of PAC channels was also induced by lactic acid, propionic acid, itaconic acid, and β-hydroxybutyrate. Weak acids also inhibited recombinant wildtype hPAC channels and PAC-like currents in hiPSC-derived cardiomyocytes. Replacement of the extracellular arginine 93 by an alanine (hPAC–Arg93Ala) strongly reduced the inhibition by some weak acids, including arachidonic acid. Although lactic acid inhibited PAC, it did not reduce the proton-induced cytotoxicity examined in wildtype HEK 293 cells. To conclude, weak acids inhibit PAC via an extracellular mechanism involving Arg93. These data warrant further investigations into the regulation of the PAC channel by endogenous weak acids. Full article

Acute lung injury (ALI) is a fatal respiratory disease caused by excessive inflammation. Chelerythrine chloride (CH), an isoquinoline alkaloid, exhibits diverse biological activities. The research focused on assessing CH’s therapeutic effects against LPS-mediated ALI in mice and its underlying mechanisms. The anti-inflammatory effects of CH were evaluated both in LPS-induced RAW264.7 cells and ALI mouse model. An amount of 2.5 μM CH significantly inhibited the secretion of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β in RAW264.7 cells. CH treatment notably mitigated the thickened alveolar septa and reduced edema in LPS-induced ALI in mice. Activity-based protein profiling (ABPP) technology was employed to identify the targets of CH. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was one of the direct targets of CH identified by ABPP. CH could downregulate the production of pyruvate. Furthermore, CH reduced the extracellular acidification rate (ECAR) while increasing the oxygen consumption rate (OCR) in LPS-stimulated RAW264.7 cells. All results suggest that CH mitigates LPS-induced ALI by targeting GAPDH and inhibiting glycolysis. This study reveals preliminary anti-inflammatory mechanisms of CH and its therapeutic potential for ALI. Full article

Background/Objectives: Tranexamic acid (TXA) reduces mortality in patients with massive hemorrhage by inhibiting fibrinolysis. However, it is associated with an increased risk of thrombosis. The activation of neutrophil extracellular traps (NETs) has been implicated in the formation of thrombosis. This study investigated the effects of tranexamic acid on circulating and localized NETs, neutrophils, platelets, and the vascular endothelium in a mouse model of thrombosis. Methods: A ferric chloride-induced thrombosis mouse model was used and divided into five groups: a Control group that received intraperitoneal phosphate-buffered saline (PBS), and four experimental groups that received intraperitoneal tranexamic acid at doses of 5 mg/kg, 10 mg/kg, 20 mg/kg, and 30 mg/kg, respectively. To evaluate the expression of circulating and localized NETs, neutrophils, platelets, vascular endothelial cells, fibrinogen, and D-dimer, the following markers were analyzed: myeloperoxidase (MPO), neutrophil marker, cluster of differentiation (CD)31, CD34, fibrinogen α-chain, and D-dimer. These markers were assessed using flow cytometry, immunohistofluorescence staining, and Western blot analysis. The primary endpoint was the differential expression of anti-MPO antibody among the groups. Results: In total, data from 20 thrombosis mouse models were analyzed. For each group, four samples were assessed by flow cytometry, and three samples by immunohistofluorescence staining and Western blot analysis, respectively. In the flow cytometric analysis, circulating anti-MPO antibody expression was significantly higher in the TXA 20 and TXA 30 groups compared to the Control group (p = 0.001 and p = 0.001, respectively). Immunohistofluorescence staining revealed that D-dimer expression in the thrombotic femoral artery was significantly lower in the TXA 5, TXA 10, and TXA 20 groups compared to the Control group (p = 0.005; p = 0.018; p = 0.004, respectively), but significantly higher in the TXA 30 group than in the Control group (p = 0.044). Similarly, the expression of anti-fibrinogen antibody was significantly lower in the TXA 5, TXA 10, and TXA 20 groups compared to the Control group (p = 0.038; p = 0.003; p = 0.041, respectively). Western blot analysis showed no significant differences in the expression of anti-Ly6B.2, anti-fibrinogen, and anti-CD31 antibodies among the groups. Conclusions: The present study suggests that high-dose tranexamic acid (30 mg/kg) administration may increase circulating NETs and localized D-dimer levels, indicating a higher potential for thrombosis in a thrombosis mouse model. These findings imply that the prothrombotic effects of tranexamic acid may be dose-dependent and could vary based on underlying disease conditions. Therefore, the careful dosage adjustment of tranexamic acid may be necessary, particularly in patients at risk of thrombosis. Full article

This study investigated the nitrogen removal performance of a three-stage AO reactor for refractory TN and the changes in microbial community structure within the activated sludge system under varying sodium chloride concentration conditions. Under an influent sodium chloride concentration of 0 g/L with sufficient carbon source, the removal rates of Total Nitrogen (TN), Chemical Oxygen Demand (COD_cr), and Ammonium (NH₄⁺-N) remained stable at 98%, 99.7%, and 99.9%, respectively. When the sodium chloride concentration increased to 20 g/L, the activity of AOB was significantly inhibited, with removal efficiency rates dropping to 83%, 89%, and 70%, respectively, and the NAR increasing to 91.97%. Analytical results demonstrated that both ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) exhibited inhibited metabolic activities, with NOB experiencing earlier functional impairment. Under NaCl concentrations ≤ 10 g/L, conventional nitrogen removal via nitrification–denitrification (ND) remained dominant. When NaCl concentrations exceeded 10 g/L, due to the accumulation of NO₂⁻-N, the phyla Planctomycetota and Proteobacteria maintained dominance in the microbial community, while partial nitrification (PN) and denitrification pathways gradually replaced ND. Extracellular polymeric substance (EPS) secretion emerged as the primary microbial defense mechanism against salinity stress. Experimental findings informed proposed strategies including phased acclimatization for salt-tolerance enhancement, EPS production regulation, and targeted enrichment of functional consortia, which collectively improved the denitrification efficiency by 18.7–22.3% under salinity levels ≤ 20 g/L. This study provides theoretical foundations and technical references for process optimization in hypersaline industrial wastewater treatment systems. Full article

In recent years, several plastic-degrading enzymes with efficient depolymerization abilities for PET have been reported. Here, we report a bioprocess for mixed PET waste depolymerization using crude extracellularly expressed enzymes in E. coli. The enzymes, namely FastPETase, LCC, and LCC^ICCG, were screened to depolymerize amorphous PET powder and films of different sizes and crystallinity. FastPETase, LCC, and LCC^ICCG achieved approximately 25, 34, and 70% depolymerization, respectively, when applied to 13 g L⁻¹ of PET film, powder, or mixed waste in optimized enzyme conditions without any pH control. The yield of terephthalic acid in the hydrolytic process was maximum for LCC^ICCG followed by LCC and FastPETase. Finally, extracellular LCC^ICCG-producing E. coli cells were cultivated using minimal media supplemented with 0.1% ammonium chloride and 1% glycerol as nitrogen and carbon sources in a bioreactor with a final protein content and specific activity of 119 ± 5 mg L⁻¹ and 1232 ± 18 U mg⁻¹, respectively. Nearly complete depolymerization of 13 g L⁻¹ PET and 23.8 g L⁻¹ post-consumer PET was achieved in 50 h using crude LCC^ICCG supernatant, without enzyme purification, at 62 °C. A bioprocess was thus developed to depolymerize 100 g L⁻¹ mixed PET trays and bottle waste (MW1 and MW2), reaching 78% and 50% yield at 62 °C with a crude enzyme loading of 2.32 mg g⁻¹ PET in 60 h. The results demonstrate an easy PET depolymerization strategy that could be exploited in large-scale facilities for efficient plastic waste treatment. Full article

Traumatic brain injuries (TBIs) cause direct central nervous system injury. The presentation depends on the location, the type, and the severity of the injury. Additional injury may develop secondary to compression, the disruption of cerebral perfusion, and changes in sodium levels, resulting in either cellular edema or dehydration. Plasma osmolality (Posm) is a critical parameter influenced by solute concentrations, including sodium, glucose, and urea, and is a relevant concern when considering sodium levels in these patients. While Posm can be calculated using a standard formula, direct measurements via osmometry offer better accuracy. It is essential to differentiate between osmolality and tonicity; the latter refers specifically to effective solutes that drive water movement in the extracellular fluid. Sodium and its anions are effective solutes, whereas urea and glucose have variable effects due to their permeability and insulin dependence. Following TBI, the dysregulation of osmoregulation may occur and affect neurological outcomes. Osmoreceptors in the brain regulate arginine vasopressin secretion in response to changes in effective solute concentrations, with sodium chloride and mannitol being potent stimuli. The regulation of plasma osmolality, typically maintained within ±5% of the 280–295 mOsm/kg H₂O range, is crucial for homeostasis and relies on antidiuresis and thirst mechanisms. This review narrative underscores the complexities of osmoregulation in the context of TBIs and their clinical implications, particularly concerning the development of conditions such as diabetes insipidus, the syndrome of inappropriate antidiuretic hormone secretion, and abnormal thirst. Full article

Cancer is a complex disease characterized by uncontrolled cell proliferation at various levels, leading to tumor growth and spread. This review focuses on the role of ion homeostasis in cancer progression. It describes a model of ion-mediated regulation in both normal and cancerous cell proliferation. The main function of this system is to maintain the optimal number of cells in the body by regulating intra- and extracellular ion content. The review discusses the key points of ion regulation and their impact on tumor growth and spread during cancer development. It explains that normal levels of sodium, potassium, calcium, chloride, and hydrogen ions are regulated at different levels. Damage to ion transport mechanisms during carcinogenesis can lead to an increase in sodium cations and water content in cells, disrupting the balance of calcium and hydrogen ions. This, in turn, can lead to chromatin compaction reduction, gene overexpression, and instability at the epigenetic and genomic levels, resulting in increased cell proliferation and mutagenesis. Restoring normal ion balance can reduce the proliferative potential of both normal and tumor cell populations. The proposed model of systemic ionic regulation of proliferation aims to reconcile diverse data related to cell mitotic activity in various physiological conditions and explain tumor growth. Understanding the mechanisms behind pathological cell proliferation is important for developing new approaches to control ion homeostasis in the body, potentially leading to more effective cancer treatment and prevention. Full article

In this preliminary study, the long-term effects of calcium chloride crosslinking concentration on viability of 16HBE14o- human bronchial epithelial cells embedded in alginate-extracellular matrix (ECM) or alginate–methylcellulose–ECM hydrogels have been investigated. There is currently a limited understanding regarding the effects of crosslinking solution concentration on lung epithelial cells embedded in hydrogel. Furthermore, the effects of calcium chloride concentration in crosslinking solutions on other cell types have not been reported regarding whether the addition of viscosity and stiffness tuning agents such as methylcellulose will alter the responses of cells to changes in calcium chloride concentration in crosslinking solutions. While there were no significant effects of calcium chloride concentration on cell viability in alginate–ECM hydrogels, there is a decrease in cell viability in alginate–methylcellulose–ECM hydrogels crosslinked with 300 mM calcium chloride crosslinking solution. These findings have implications in the maintenance of 16HBE14o- 3D cultures with respect to the gelation of alginate with high concentrations of ionic crosslinking solution. Full article

Exosomes are extracellular nanovesicles secreted by cells that efficiently deliver therapeutic cargo for cancer treatment. However, because exosomes are present in low quantities and have limited target specificity, internal and external stress stimulation has been studied to increase exosome efficiency. Inspired by these studies, the uptake efficiency of cobalt chloride-induced hypoxic cancer cell-secreted exosomes was evaluated. Western blotting and RT-PCR data revealed increased exosome secretion and different protein compositions exhibited by hypoxic exosomes (H-Exos) compared to natural normoxic exosomes (N-Exos). Furthermore, these H-Exos were continuously stimulated using low-intensity ultrasound (LICUS) at an intensity of 360 mW/cm² and a frequency of 3 MHz in vitro and 1 MHz in vivo. Hyperthermic and mechanical stress caused by ultrasound successfully improved exosome uptake via clathrin-mediated pathways, and confocal laser microscopy showed strong internal localization near the target cell nuclei. Finally, LICUS-equipped H-Exos were loaded with hydrophobic curcumin (H-Exo-Cur) and used to treat parent HepG2 liver cancer cells. The UV–Vis spectrophotometer displayed enhanced stability, solubility, and concentration of the encapsulated drug molecules. In MTT and FACS studies, approximately 40 times higher cell death was induced, and in animal studies, approximately 10 times higher tumor sizes were suppressed by LICUS-assisted H-Exo-Cur compared to the control. In this study, the delivery platform constructed demonstrated enormous potential for liver cancer therapy. Full article

Dry eye is characterized by persistent instability and decreased tear production, which are accompanied by epithelial lesions and inflammation on the surface of the eye. In our previous paper, we reported that supplementation with Limosilactobacillus fermentum HY7302 (HY7302) could inhibit corneal damage in a benzalkonium chloride (BAC)-induced mouse model of dry eye, through its effects in gut microbiome regulation. The aim of this study was to determine what functional extracellular substances can alter the inflammatory response of conjunctival cells. We isolated exosomes from HY7302 probiotic culture supernatant, analyzed their morphological characteristics, and found that their average size was 143.8 ± 1.1 nm, which was smaller than the exosomes from the L. fermentum KCTC 3112 strain. In addition, HY7302-derived exosomes significantly reduced the levels of genes encoding pro-inflammatory cytokines, including interleukin (IL)-20, IL-8, IL-6, and IL-1B, in BAC-treated human conjunctival cells. Moreover, HY7302-derived exosomes significantly increased the levels of genes encoding tight junction proteins, including TJP1, TJP2, and occludin-1, in Caco-2 cells. Lastly, the HY7302 exosomes reduced mRNA expression levels of IL1B, IL20, IL6, IL8, and NFAT5 in a transwell coculture system. Our findings indicate that HY7302 exosomes have potential for use in the treatment of ocular inflammation-related dry eye disease, through gut–eye axis communication via exosomes. Full article

The sodium chloride cotransporter (NCC) is essential for electrolyte balance, blood pressure regulation, and pathophysiology of hypertension as it mediates the reabsorption of ultrafiltered sodium in the renal distal convoluted tubule. Given its pivotal role in the maintenance of extracellular fluid volume, the NCC is regulated by a complex network of cellular pathways, which eventually results in either its phosphorylation, enhancing sodium and chloride ion absorption from urines, or dephosphorylation and ubiquitination, which conversely decrease NCC activity. Several factors could influence NCC function, including genetic alterations, hormonal stimuli, and pharmacological treatments. The NCC’s central role is also highlighted by several abnormalities resulting from genetic mutations in its gene and consequently in its structure, leading to dysregulation of blood pressure control. In the last decade, among other improvements, the acquisition of knowledge on the NCC and other renal ion channels has been favored by studies on extracellular vesicles (EVs). Dietary sodium and potassium intake are also implicated in the tuning of NCC activity. In this narrative review, we present the main cornerstones and recent evidence related to NCC control, focusing on the context of blood pressure pathophysiology, and promising new therapeutical approaches. Full article

Background: Chloride Intracellular Channel 4 (CLIC4) plays a versatile role in cellular functions beyond its role in primary chloride ion transport. Notably, many studies found an association between CLIC4 expression and cancers. However, the correlation between CLIC4 and glioma remains to be uncovered. Methods: A total of 3162 samples from nine public datasets were analyzed to reveal the relationship between CLIC4 expression and glioma malignancy or prognosis. Immunohistochemistry (IHC) staining was performed to examine the results in an in-house cohort. A nomogram model was constructed to predict the prognosis. Functional enrichment analysis was employed to find CLIC4-associated differentially expressed genes in glioma. Immune infiltration analysis, correlation analysis, and IHC staining were employed, aiming to examine the correlation between CLIC4 expression, immune cell infiltration, and ECM (extracellular matrix)-related genes. Results: The expression level of CLIC4 was correlated with the malignancy of glioma and the prognosis of patients. More aggressive gliomas and mesenchymal GBM are associated with a high expression of CLIC4. Gliomas with IDH mutation or 1p19q codeletion express a low level of CLIC4, and a high expression of CLIC4 correlates with poor prognosis. The nomogram model shows a good predictive performance. The DEGs (differentially expressed genes) in gliomas with high and low CLIC4 expression are enriched in extracellular matrix and immune functions. On the one hand, gliomas with high CLIC4 expression have a greater presence of macrophages, neutrophils, and eosinophils; on the other hand, a high CLIC4 expression in gliomas is positively associated with ECM-related genes. Conclusions: Compared to glioma cells with low CLIC4 expression, gliomas with high CLIC4 expression exhibit greater malignancy and poorer prognosis. Our findings indicate that a high level of CLIC4 correlates with high expression of ECM-related genes and the infiltration of macrophages, neutrophils, and eosinophils within glioma tissues. Full article

Potassium ions (K⁺) are critical electrolytes that regulate multiple functions in immune cells. Recent studies have shown that the elevated concentration of extracellular potassium in the tumor interstitial fluid limits T cell effector function and suppresses the anti-tumor capacity of tumor-associated macrophages (TAMs). The effect of excess potassium on the biology of myeloid-derived suppressor cells (MDSCs), another important immune cell component of the tumor microenvironment (TME), is unknown. Here, we present data showing that increased concentrations of potassium chloride (KCl), as the source of K⁺ ions, facilitate autophagy by increasing the expression of the autophagosome marker LC3β. Simultaneously, excess potassium ions significantly decrease the expression of arginase I (Arg I) and inducible nitric oxide synthase (iNOS) without reducing the ability of MDSCs to suppress T cell proliferation. Further investigation reveals that excess K⁺ ions decrease the expression of the transcription factor C/EBP-β and alter the expression of phosphorylated kinases. While excess K⁺ ions downregulated the expression levels of phospho-AMPKα (pAMPKα), it increased the levels of pAKT and pERK. Additionally, potassium increased mitochondrial respiration as measured by the oxygen consumption rate (OCR). Interestingly, all these alterations induced by K⁺ ions were abolished by the autophagy inhibitor 3-methyladenine (3-MA). Our results suggest that hyperosmotic stress caused by excess K⁺ ions regulate the mitochondrial respiration and signaling pathways in MDSCs to trigger the process of autophagy to support MDSCs’ immunosuppressive function by mechanisms independent of Arg I and iNOS. Overall, our in vitro and ex vivo findings offer valuable insights into the adaptations of MDSCs within the K⁺ ion-rich TME, which has important implications for MDSCs-targeted therapies. Full article

Regulating membrane potential is key to cellular function. For many animal cells, resting membrane potential is predominantly driven by a family of K2P (two-pore domain) potassium channels. These channels are commonly referred to as leak channels, as their presence results in the membrane being permeable to K⁺ ions. These channels, along with various pumps and exchangers, keep the cell resting membrane potential (Rp) relatively close to potassium’s equilibrium potential (E_K); however, in many cells, the resting membrane potential is more depolarized than the E_K due to a small Na⁺ ion leak. Raising [Ca²⁺]_O (extracellular Ca²⁺ concentration) can result in hyperpolarization of the membrane potential from the resting state. The mechanism for this hyperpolarization likely lies in the blockage of a Na⁺ leak channel (NALCN) and/or voltage-gated Na⁺ channels. The effects may also be connected to calcium-activated potassium channels. Using Drosophila melanogaster, we here illustrate that changing [Ca²⁺]_O from 0.5 to 3 mM hyperpolarizes the muscle. Replacing NaCl with LiCl or choline chloride still led to hyperpolarization when increasing [Ca²⁺]_O. Replacing CaCl₂ with BaCl₂ results in depolarization. K2P channel overexpression in the larval muscle greatly reduces the effects of [Ca²⁺]_O on cell membrane potential, likely because potential is heavily driven by the E_K in these muscles. These experiments provide an understanding of the mechanisms behind neuronal hypo-excitability during hypercalcemia, as well as the effects of altered expression of K2P channels on membrane potential. Full article