Alexei Diakov, Florian Sure, Alexandr V Ilyaskin, Christoph Korbmacher
{"title":"Acute activation of human epithelial sodium channel (ENaC) by serum and glucocorticoid inducible kinase 1 (SGK1) requires prior cleavage of the channel's γ-subunit at its proximal cleavage site.","authors":"Alexei Diakov, Florian Sure, Alexandr V Ilyaskin, Christoph Korbmacher","doi":"10.1007/s00424-025-03099-z","DOIUrl":"10.1007/s00424-025-03099-z","url":null,"abstract":"<p><p>Serum and glucocorticoid inducible kinase 1 (SGK1) is a key regulator of the epithelial sodium channel (ENaC). In rat ENaC, the serine residue 621 (S621) in the channel's α-subunit is essential for acute channel activation by SGK1 in outside-out patches. Phosphorylation at S621 probably turns previously silent channels into channels with a high open probability. This is reminiscent of proteolytic ENaC activation resulting from cleavage of the channel's γ-subunit at specific proximal and distal cleavage sites and the release of an inhibitory peptide tract. The first aim of this study was to demonstrate that human ENaC could also be activated acutely by SGK1 and that this depended on the homologous phosphorylation site S594 in human αENaC. Secondly, we wanted to explore whether human ENaC activation by SGK1 depended on the cleavage state of γENaC. Outside-out patch-clamp recordings in Xenopus laevis oocytes expressing human αβγENaC revealed the critical importance of S594 for acute channel activation by SGK1. The latter was not additive to proteolytic channel activation. Interestingly, preventing proximal cleavage in human γENaC completely abolished the stimulatory effect of SGK1. Moreover, tethering the inhibitory peptide in γENaC to its binding site via an engineered disulfide bond prevented stimulation by SGK1. We conclude that ENaC activation by SGK1 requires prior cleavage of γENaC at its proximal cleavage site. Together, these results reveal that SGK1-mediated stimulation of human ENaC is intricately linked to the proteolytic processing of the channel's γ-subunit, emphasizing a previously underappreciated interplay between kinase and protease regulatory pathways.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1061-1074"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310850/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Clara A Simacek, Sergei Kirischuk, Thomas Mittmann
{"title":"Presynaptic maturation of inhibitory connections onto vasoactive intestinal polypeptide-expressing GABAergic interneurons in the mouse barrel field.","authors":"Clara A Simacek, Sergei Kirischuk, Thomas Mittmann","doi":"10.1007/s00424-025-03101-8","DOIUrl":"10.1007/s00424-025-03101-8","url":null,"abstract":"<p><p>Vasoactive intestinal polypeptide-expressing inhibitory interneurons (VIP-INs) in the adult barrel cortex are crucial for mediating active whisking (AW) by disinhibiting pyramidal neurons. Past studies have investigated the development of VIP-IN network integration, focusing mainly on the excitatory network or the postsynaptic side of the inhibitory network. Hence, we aimed to explore the inhibitory network integration of VIP-INs, concentrating on the presynaptic side. We addressed this by investigating VIP-INs in three different age groups (postnatal day (P)8-P10, P14-P16, and P30-P36) in Vip-IRES-cre x tdTomato mice with whole-cell patch clamp recordings. By placing a stimulation electrode into L4 of the barrel field, we elicited electrically-evoked inhibitory postsynaptic currents (eIPSCs) in L2/3 VIP-INs following a high-frequency stimulation. We then analysed recorded eIPSCs by applying the binomial model of synaptic transmission. Our results show significant increases in both the number of readily-releasable vesicles and the presynaptic release probability between P9 and P15, suggesting that the inhibitory network integration is at least partially conducted via a presynaptic functional maturation. Despite an increase in the release probability, synaptic depression is decreased at P30-P36 due to an accelerated vesicle replenishment rate within the same time window. Lastly, asynchronous vesicle release decreases in favour of a stimulus-locked signal transmission by P30-P36. Our results suggest a maturation of the inhibitory projections towards a strong, precise, and stimulus-locked inhibition. This can be physiologically relevant to define the temporal precision of AW at the relevant frequencies.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1089-1101"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310910/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144485507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Holger H Burchert, William W Stringer, Ranjan K Dash
{"title":"Oxygen dissociation curve inflection point during incremental exercise: a trigger for the Bohr effect.","authors":"Holger H Burchert, William W Stringer, Ranjan K Dash","doi":"10.1007/s00424-025-03100-9","DOIUrl":"10.1007/s00424-025-03100-9","url":null,"abstract":"<p><p>We previously hypothesized that the inflection point of the oxygen dissociation curve (ODC) is linked to the gas exchange threshold (GET) during cardiopulmonary exercise testing. This hypothesis was supported by femoral venous blood gas data sampled during constant exercise below and above the GET, which showed that the ODC shifts rightward at the GET. What had gone unnoticed since these original observations in 1994 was that this rightward shift begins slightly earlier, precisely when the oxygen saturation crosses the ODC inflection point. To investigate this phenomenon, we analyzed the 1994 femoral venous blood gas data obtained during cardiopulmonary exercise testing using a modern validated mechanistic biochemical model of oxygen (O<sub>2</sub>), carbon dioxide (CO<sub>2</sub>), and proton binding to hemoglobin (Hb). We constructed the ODC for each data point, as well as the in vivo ODC-a composite curve reflecting changes in dynamic blood chemistry during exercise-to assess its alignment with the GET. The model revealed that, at the in vitro ODC inflection point (36% O<sub>2</sub>Hb saturation), the amounts of CO<sub>2</sub> bound to Hb equalized with HbNH<sub>3</sub><sup>+</sup> eventually predominating. This equilibrium apparently triggered the Bohr shift, steepening the in vivo ODC to improve O<sub>2</sub> unloading to the tissues. Shortly afterwards, the in vivo ODC reached its inflection point, matching the measured GET. Our findings support that the GET is mechanistically linked to the in vivo ODC inflection point. These results highlight the physiological relevance of determining the ODC inflection point and its alignment with HbNH<sub>3</sub><sup>+</sup> and CO<sub>2</sub> binding as critical factors in understanding ODC shifts during cardiopulmonary exercise testing.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1075-1087"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310897/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144601157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Molecular determinants of HERG potassium channel blockade by domiphen bromide and benzethonium chloride.","authors":"Feng Tang, Zuoxian Lin, Rongqi Huang, Zhiyuan Li","doi":"10.1007/s00424-025-03104-5","DOIUrl":"10.1007/s00424-025-03104-5","url":null,"abstract":"<p><p>Domiphen bromide (DMP) and benzethonium chloride (BZT) are synthetic quaternary ammonium compounds widely used as disinfectants. Both agents are potent inhibitors of the human ether-à-go-go-related gene (HERG) potassium channel, a key contributor to cardiac repolarization. Dysfunction of HERG is associated with long QT syndrome and arrhythmias, yet the molecular mechanisms underlying DMP and BZT inhibition remain incompletely understood. In this study, we employed site-directed mutagenesis and whole-cell patch-clamp recording to identify key residues mediating DMP and BZT binding. Wild-type and nine mutant HERG channels were expressed in HEK-293 T cells, targeting residues in the pore helix (T623A, S624A, V625A), S6 helix (G648A, Y652A, F656A), S5-pore linker (S631A), and S5-S6 connector (N588K), including a double mutant (N588K/S631A). DMP exhibited strong dependence on S624, V625, Y652, N588, and S631, whereas BZT primarily involved S624, V625, and Y652. Computational docking revealed that DMP forms hydrogen bonds, π-cation, and π-π interactions with S624 and Y652, while BZT interacts through π-cation and π-π stacking with Y652 and hydrophobic contacts with S624. Importantly, our data highlight the quaternary ammonium group as a critical pharmacophore, mediating strong interactions with serine and aromatic residues via π-cation, electrostatic, and hydrogen bonding mechanisms, contributing to high-affinity channel blockade. In conclusion, this study defines the molecular determinants underlying DMP and BZT binding to the HERG channel and provides mechanistic insight that may guide the design of safer therapeutics with minimized HERG liability.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1119-1130"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144675438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ying Liu, Xuhui Feng, Han Wu, Tianxiang Gui, Mingfeng Fu, Xudong Luo, Lei Zhao, Li-Ming Chen
{"title":"IRBITs, signaling molecules of great functional diversity.","authors":"Ying Liu, Xuhui Feng, Han Wu, Tianxiang Gui, Mingfeng Fu, Xudong Luo, Lei Zhao, Li-Ming Chen","doi":"10.1007/s00424-025-03095-3","DOIUrl":"10.1007/s00424-025-03095-3","url":null,"abstract":"<p><p>IRBIT1 and IRBIT2 (collectively, the IRBITs) are signaling molecules with great universality in their expression (ubiquitous distribution in all major tissues in animals) and considerable versatility in their biological functions. Structurally, the IRBITs are highly homologous to S-adenosyl-L-homocysteine hydrolase (AHCY). However, the IRBITs had lost the catalytic activity during the evolution but gained new functions by the addition of a unique N-terminal IRBIT domain. By direct protein interaction, the IRBITs modulate the functions of an array of target proteins of distinct biological functions, ranging from membrane channels and transporters to cytosolic protein kinase, lipid kinases, ribonucleotide reductase, etc. The interaction of the IRBITs with specific target proteins is modulated by the redox couple NAD<sup>+</sup>/NADH. The IRBITs are involved in the regulation of many cellular processes, such as Ca<sup>2+</sup> signaling, intracellular pH regulation, transepithelial transport of electrolytes and fluid, apoptosis, and DNA metabolism. However, what we have known about the IRBITs is likely just the tip of the iceberg. The present review covers the expression and distribution, physiological and pathological roles, and the structural organization of the IRBITs. It provides a comprehensive review on the binding partners of the IRBITs. Finally, the review addresses the evolution of the IRBITs in reference to the evolution of AHCY.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1007-1036"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144187599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Soft tissue calcifications in chronic kidney disease-beyond the vasculature.","authors":"Abul Fajol, Christian Faul","doi":"10.1007/s00424-025-03098-0","DOIUrl":"10.1007/s00424-025-03098-0","url":null,"abstract":"<p><p>Inappropriate mineralization of soft tissues, also called ectopic calcification, is a well-known pathology in chronic kidney disease (CKD) that is associated with increases in systemic phosphate levels. Vascular calcification is a major contributor to cardiovascular injury and high mortality rates in CKD patients. Therefore, most animal and human studies have focused on the vasculature when describing ectopic calcifications and on the pathologic actions of elevated phosphate on vascular smooth muscle cells in this process. The extent of calcifications within soft tissues beyond the vasculature is not well described, and the involvement of cell types other than vascular smooth muscle cells is not clear. Here we provide a summary of CKD-associated extravascular calcifications in various tissues, which includes the lung, the gastrointestinal system, the liver, the skin, and the brain. Since phosphate elevations and widespread ectopic calcifications do not only occur in the context of CKD, but also in rare genetic disorders that affect the regulators of phosphate metabolism, the cellular transporters of phosphate and the factors protecting from mineral depositions outside of bone, we also discuss these pathologic scenarios. We describe different types of ectopic calcification to flesh out common aspects as well as differences in the potential mechanisms and target cell types. We postulate that phosphate elevations might act in various ways and on various tissues, which together causes a wide spectrum of phosphate-induced pathologies in CKD.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1037-1059"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144226190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ayşegül Bahar Özocak, Leyla Semiha Şen, Leman Arslan Arıtürk, Nur Özkeçeci, Meral Yüksel, İrem Peker Eyüboğlu, Can Erzik, Naziye Özkan Yenal, Feriha Ercan, Ali Emre Atıcı, Berrak Ç Yeğen
{"title":"Elabela alleviates ischemia/reperfusion-induced hepatic and remote organ injury by inhibiting oxidative stress in rats.","authors":"Ayşegül Bahar Özocak, Leyla Semiha Şen, Leman Arslan Arıtürk, Nur Özkeçeci, Meral Yüksel, İrem Peker Eyüboğlu, Can Erzik, Naziye Özkan Yenal, Feriha Ercan, Ali Emre Atıcı, Berrak Ç Yeğen","doi":"10.1007/s00424-025-03105-4","DOIUrl":"10.1007/s00424-025-03105-4","url":null,"abstract":"<p><p>Hepatic injury is one of the most critical problems in major liver surgeries, trauma, sepsis or shock. The novel Elabela (ELA) peptide was shown to exert protective effects against cardiac and renal injury. We hypothesized that ELA could also have protective effects in hepatic ischemia-reperfusion (HI/R) injury and associated remote organ injury. Male (n = 37) and female (n = 37) Sprague-Dawley rats were used. Rats were divided into short-term and long-term HI/R injury groups. Each group was then divided into saline-treated, N-acetylcysteine-treated (NAC, 150 mg/kg) and ELA-treated (40 μg/kg) subgroups. Immediately before hepatic ischemia and during reperfusion, rats were subcutaneously injected with saline, NAC or ELA, while injections in long-term groups were continued twice a day for four days. Short-term and long-term sham-operation groups received saline injections. Hepatic blood flow was measured via laser Doppler flowmetry. Intracardiac blood was obtained for analyses of aminotransferase, alanine aminotransferase, bilirubin, urea, creatinine and interleukin (IL)-6. Caspase-3 and 8-hydroxy-2'-deoxyguanosine levels were determined and histopathological analyses (hematoxylin-eosin and alpha-smooth muscle actin (SMA) immunohistochemical staining) were performed in hepatic tissues. Levels of malondialdehyde, antioxidant glutathione, myeloperoxidase activity, luminol and lucigenin-enhanced chemiluminescence were measured in liver, lung, and kidney. Significant improvement in hepatic blood flow was observed in both short- and long-term ELA-treated groups. HI/R-induced elevations in reactive oxygen species in all the studied tissues were decreased by ELA, indicating its efficient radical scavenging function similar to NAC treatment. ELA treatment improved hepatic function tests and alleviated liver fibrosis, as detected by increased alpha-SMA-immunoreactivity. Serum IL-6 levels were increased by ELA treatment, suggesting its role in the activation of IL-6-dependent intracellular pathways which may contribute to hepatocyte proliferation and liver regeneration. Similar to the common use of NAC in hepatic surgery, Elabela appears to have a therapeutic potential in alleviating the consequences of hepatic postreperfusion injury.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"1103-1118"},"PeriodicalIF":2.9,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144659829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ivis V O Martins, Thales M H Dourado, Gustavo F Pimenta, Marcela M Blascke de Mello, Aline G Fedoce, Wanessa M C Awata, Michele M Castro, Rita C Tostes, Carlos R Tirapelli
{"title":"Ethanol-induced dysfunction of the mesenteric perivascular adipose tissue is driven by mineralocorticoid receptors.","authors":"Ivis V O Martins, Thales M H Dourado, Gustavo F Pimenta, Marcela M Blascke de Mello, Aline G Fedoce, Wanessa M C Awata, Michele M Castro, Rita C Tostes, Carlos R Tirapelli","doi":"10.1007/s00424-025-03094-4","DOIUrl":"10.1007/s00424-025-03094-4","url":null,"abstract":"<p><p>The renin-angiotensin-aldosterone system (RAAS) is critical in ethanol-induced vascular dysfunction. Mineralocorticoid receptors (MR) trigger ethanol-induced vascular hypercontractility through pro-oxidative and pro-inflammatory effects. However, the contribution of MR to ethanol-induced perivascular adipose tissue (PVAT) dysfunction is unknown. Appreciating the importance of MR to PVAT dysfunction in distinctive pathological conditions, we investigated whether MR would play a role in ethanol-induced PVAT dysfunction. With this purpose, male Wistar Hannover rats were treated with ethanol 20% (in volume ratio) and/or potassium canrenoate [a MR antagonist (MRA); 30 mg/kg/day, gavage] for 5 weeks. Ethanol increased the circulating levels of aldosterone and impaired acetylcholine-induced relaxation of mesenteric arteries with, but not without PVAT. Antagonism of MR prevented ethanol-induced impairment in acetylcholine relaxation as well as the reduction of leptin levels and reactive oxygen species (ROS) overproduction in the mesenteric PVAT (mPVAT) from ethanol-treated rats. Ethanol promoted neutrophil accumulation and augmented the concentration of tumor necrosis factor (TNF)-α in the mPVAT and these responses were prevented by the MRA. Functional assays showed that tiron [a scavenger of superoxide (O<sub>2</sub><sup>•-</sup>)] and etanercept (an antibody anti-TNF-α) failed to reverse the impairment of acetylcholine-induced relaxation promoted by ethanol. In mesenteric arteries, antagonism of MR prevented ROS generation, lipoperoxidation, and increased TNF-α levels induced by ethanol. In conclusion, our findings suggest that MR is involved in ethanol-induced dysfunction of mPVAT. This study enhances our understanding of how ethanol exerts harmful effects on the cardiovascular system, highlighting PVAT as a target for these detrimental effects.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"919-933"},"PeriodicalIF":2.9,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144079399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Role of oxidative/nitrosative stress in dysfunction of rat's intracerebral parenchymal arterioles in low sodium environment in the presence of vasopressin.","authors":"Marta Aleksandrowicz","doi":"10.1007/s00424-025-03097-1","DOIUrl":"10.1007/s00424-025-03097-1","url":null,"abstract":"<p><p>Hyponatremia is the most common electrolyte disturbance in hospitalized patients. Symptoms of hyponatremia include attention deficits and cognitive impairments. The cause of such abnormalities may be disturbances in the regulation of microcirculation. Previous studies have shown that increased vasopressin (AVP) concentration to 15 pg/ml in the presence of decreased Na<sup>+</sup> concentration to 121 mM, which mimics AVP-associated hyponatremia in vivo leads to dysfunction, i.e., constriction and impaired endothelial regulation of small intracerebral blood vessels-parenchymal arterioles (PA). One of the possible causes of this dysfunction may be excessive production of superoxide anion (O2<sup>•-</sup>). The superoxide anion binds nitric oxide (NO) in a reaction that produces aggressive nitrogen-free radical, peroxynitrite (ONOO<sup>-</sup>), which simultaneously reduces the bioavailability of NO. The present studies were performed in the organ chamber on isolated, perfused, and pressurized rats' PA in low sodium environment in the presence of AVP. These studies aimed to investigate the mechanism leading to PA dysfunction, i.e., constriction and disturbed endothelial regulation. L-NAME (N(ω)-nitro-L-arginine methyl ester) did not elicit constriction of PA, indicating reduced involvement of NO in maintaining basal tone of PA. Vasopressin V<sub>1a</sub> receptor antagonist (SR 49059), endothelin ET<sub>A</sub>/ET<sub>B</sub> receptors antagonist (PD 142,893), peroxynitrite decomposition catalyst (FeTMPyP) and ROS scavengers: superoxide dismutase (SOD) and catalase (CAT) improved studied responses. Dihydroethidium (DHE) staining confirmed the increased superoxide anion formation in low sodium environment in the presence of AVP. Thromboxane A<sub>2</sub>/prostaglandin H<sub>2</sub> receptor blocker (SQ 29,548), an inhibitor of the production of 20-HETE (HET0016), and L-arginine, a precursor of NO, did not improve dysfunctions of PA. Thus, in studied conditions, endothelial dysfunction occurs due to oxidative/nitrosative stress. These findings provide novel insight into the detrimental effects of decreased Na<sup>+</sup> concentration in the presence of increased AVP concentration that mimic hyponatremia, on the regulation of cerebral microcirculation.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"993-1005"},"PeriodicalIF":2.9,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12152088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144161246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Targeting NLRP3 inflammasome attenuates cardiac pyroptosis and fibrosis in estrogen-deficient diabetic rats.","authors":"Sukanya Phungphong, Phichaya Suthivanich, Worakan Boonhoh, Chuchard Punsawad, Zhaokang Cheng, Tepmanas Bupha-Intr","doi":"10.1007/s00424-025-03092-6","DOIUrl":"10.1007/s00424-025-03092-6","url":null,"abstract":"<p><p>Cardiac diastolic dysfunction is a hallmark of diabetic cardiomyopathy (DCM), particularly in postmenopausal women where estrogen deficiency exacerbates cardiac remodeling. This study investigated the roles of NLRP3 inflammasome activation and cardiac mast cell (CMC) behavior in diabetic ovariectomized (OVX) rat models. Female Wistar rats were divided into five groups: sham-operated, OVX, diabetic (Sham-DM), OVX-diabetic (OVX-DM), and OVX-DM treated with the NLRP3 inhibitor MCC950. Diabetes was induced using a high-calorie quick fat diet (13.8% crude fat, 24.35% crude protein, 25% sucrose; 406.80 kcal/100 g) followed by a single intraperitoneal injection of streptozotocin (30 mg/kg). MCC950 (10 mg/kg BW, intraperitoneally) was administered daily for 4 weeks. Echocardiography revealed significant diastolic dysfunction in OVX-DM rats, with increased left ventricular internal diameter (LVIDd) and reduced mitral valve E/A ratio, while MCC950 treatment partially restored diastolic function (p < 0.05). Masson's trichrome staining showed increased myocardial fibrosis in OVX-DM rats (2.59 ± 0.20%) compared to Sham-DM (1.94 ± 0.16%, p < 0.05), which was reduced with MCC950 treatment (0.88 ± 0.13%, p < 0.05). Western blot analysis demonstrated elevated expression of NLRP3, cleaved caspase-1, IL-1β, and GSDMD-N in OVX-DM hearts. MCC950 significantly reduced cleaved caspase-1, IL-1β, and GSDMD-N expression without altering NLRP3 protein levels. Additionally, mast cell degranulation was markedly increased in OVX-DM rats (62.14%) compared to controls (P < 0.05) and was attenuated by MCC950 (31.06%, P < 0.05). These findings suggest that NLRP3 inflammasome activation under conditions of estrogen deficiency and diabetes contributes to myocardial pyroptosis and mast cell degranulation, driving cardiac remodeling in postmenopausal DCM. Targeting NLRP3 pathways may provide an effective therapeutic strategy to mitigate diastolic dysfunction, fibrosis, and inflammation in diabetic hearts.</p>","PeriodicalId":19954,"journal":{"name":"Pflugers Archiv : European journal of physiology","volume":" ","pages":"935-952"},"PeriodicalIF":2.9,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144094556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}