AIM:This study aims to investigate whether the Fibroblast Growth Factor 23 (FGF23) modulates the electrical activity of sinoatrial (SAN) cells. The canonical function of FGF23 is to regulate body phosphorus and calcium homeostasis by activating the FGF1 receptors (FGFR1)/α-Klotho complex in the kidney and parathyroid glands. High levels of FGF23 can induce cardiac arrhythmias by affecting cardiomyocyte's function in an α-Klotho independent manner. Although SAN cells are not traditionally considered targets of FGF23, the presence of α-Klotho in pacemaker and not in ventricular cells has raised this possibility. METHODS:The effect of FGF23 was evaluated by patch-clamp experiments on mouse SAN and on human-induced pluripotent stem cells-derived pacemaker-like cardiomyocytes (hiPSC-derived pCMs). RESULTS:Our data reveal that mouse SAN cells express both membrane α-Klotho and FGF23 receptors (FGFR) and that 48 h tissue incubation with FGF23 (10 ng/mL) increases the spontaneous action potential (AP) frequency of these cells through an increase in the funny If current. Patch-clamp experiments carried out using the pan-FGFR inhibitor, PD173074, and SAN cells isolated from α-Klotho hypomorphic mice suggested that FGF23 effects are mediated by the activation of the FGFR-α-Klotho complex. FGFRs expression data and FGF23-induced electrical modification were further confirmed in hiPSC-derived pCMs. Indeed, 48 h incubation of these cells with FGF23 increases both the AP frequency, in a dose-dependent manner, and the If current. CONCLUSIONS:This study represents the first evidence that FGF23 directly regulates the SAN electrical activity.
AIM:Insulin deficiency due to pancreatic β-cell loss and dysfunction is a key event in the pathogenesis of T1DM and a progressive driver of T2DM. This study aims to investigate the role of AS160 in regulating mitochondrial homeostasis and insulin secretion in pancreatic β-cells, and to elucidate the underlying molecular mechanism involving its interaction with HSPA8 and activation of PINK1-Parkin-mediated mitophagy. METHODS:Insulin and AS160 levels in islets were analyzed by immunofluorescence staining. β cell-specific AS160 overexpression mice were generated via lentivirus injection, and their metabolic phenotypes were characterized. In vitro, AS160 was overexpressed or knocked down to assess its impact on cell proliferation, insulin secretion, and mitochondrial function. AS160-interacting proteins were identified by immunoprecipitation-mass spectrometry (IP-MS). RESULTS:AS160 expression was significantly decreased in islet and correlated positively with insulin levels in hyperglycemic mice. Specific overexpression of AS160 in β-cells exhibited novel protective effects for the islets and insulin levels in hyperglycemic mice. Mechanistically, AS160 overexpression in β-cells increased mitophagy and preserved mitochondrial biogenesis to maintain healthy mitochondrial homeostasis and insulin secretion. At the molecular level, HSPA8 was identified as a novel AS160-interacting protein that enhances PINK-dependent mitophagy. Knockdown of HSPA8 reversed the overexpression of AS160-induced mitophagy and mitochondrial biogenesis. CONCLUSION:Collectively, this work identifies the AS160-HSPA8 interaction as a key mechanism that sustains mitochondrial homeostasis through regulating mitophagy and mitochondrial biogenesis, thus preserving β-cell mass and function. These findings suggest that AS160 emerges as a pivotal regulator of mitochondrial homeostasis in pancreatic β-cell in vivo.
BACKGROUND:Diabetes mellitus is commonly featured with cardiac microvascular dysfunction and chronic low-grade inflammation, contributing to the progression of diabetic cardiomyopathy (DCM). Finerenone confers cardio-renal protection in diabetic settings, yet its underlying mechanisms remain incompletely defined. AIM:To explore the beneficial effects and molecular mechanisms of finerenone on cardiovascular dysfunction in uncontrolled DCM from the perspectives of neutrophil extracellular traps (NETs) formation and AKT1 phosphorylation. METHODS:Finerenone was orally administrated to db/db mice for 24 weeks. Global AKT1 S473A mutation mice and bone marrow chimera mice were subjected to high-fat diet and streptozotocin-induced diabetic mouse model. Proteomics, pharmacological network analysis, and cellular thermal shift assay were employed to identify potential molecular targets of finerenone. Multiple approaches, including immunoblotting and immunofluorescence, were used to detect NETs and related cardiac injury. RESULTS:Finerenone treatment significantly improved cardiac and microvascular injury in uncontrolled DCM, as indicated by increased microvascular density, reduced vascular leakage, and alleviated cardiac remodeling. In addition to the mineralocorticoid receptor, AKT1 phosphorylation at S473 was identified as a direct target of finerenone. Finerenone improved AKT1 phosphorylation in endothelial cells to maintain vascular barrier function and reduce damage-associated molecular patterns (DAMPs) release, thereby suppressing polymorphonuclear (PMN) infiltration and NETosis. In contrast, AKT1 phosphorylation in PMN was suppressed by finerenone for NETs inhibition and related cardiac injuries. Similarly, global and cardiac AKT1 S473A mutation accentuated uncontrolled DCM, whereas myeloid AKT1 S473A mutation improved uncontrolled DCM. CONCLUSION:Finerenone treatment mitigated microvascular dysfunction, DAMPs release, and NETs-associated cardiac injury via balancing AKT1 phosphorylation across different cell types, contributing to its cardiovascular protection in uncontrolled DCM.
AIM:We aimed to evaluate an innovative dose-response approach to assess the metaboreflex with control of intramuscular metabolic perturbation (concept of metaboreflex gain). We also investigated potential sex differences in the metaboreflex using this new approach. METHODS:Thirty participants (15 females) completed one familiarization and two experimental visits to evaluate the method and assess its reproducibility. Each visit involved four consecutive bouts of sustained isometric knee extension at 20% of maximal voluntary force interspersed with 2 min of post-exercise circulatory occlusion (PECO). Intramuscular metabolic perturbation was quantified indirectly via changes in quadriceps twitch force evoked by electrical stimulation of the femoral nerve (∆QTW). Metaboreflex gain was calculated as the ratio of ∆mean arterial pressure (∆MAP) during PECO to ∆QTW. RESULTS:We found a gradual increase in ∆MAP (p < 0.0001) that was linearly correlated with the gradual decrease in ∆QTW (p < 0.0001) during the exercise bouts (r2 = 0.93; p = 0.037). Bland-Altman analysis showed a mean bias of 0.3 ± 0.5 for metaboreflex gain. Males exhibited greater metaboreflex to PECO than females when assessed "classically" with no control of ∆QTW (∆MAP; 49.1% ± 17.9% vs. 36.5% ± 8.7%; p = 0.020), whereas there was no sex difference when assessed using the metaboreflex gain (∆MAP/∆QTW; 1.3 ± 0.6 vs. 1.8 ± 1.3; p = 0.325). The metaboreflex gain was not consistent across exercise bouts, showing that contrasting conclusions might emerge between two single assessments performed at different levels of metaboreflex activation. CONCLUSION:This study highlights the critical need for using a dose-response relationship while accounting for neuromuscular fatigue as a proxy for the metabolic stimulus when assessing the muscle metaboreflex in humans. TRIAL REGISTRATION:Clinical trials registration number: NCT06775119.
AIM:The kidney thick ascending limb (TAL) plays a key role in the transport of sodium, chloride, potassium, calcium, and magnesium. Bartter syndrome is a hypokalemic, salt-losing tubulopathy caused by impaired TAL function. Pathogenic variants in SLC12A1 or KCNJ1 cause antenatal Bartter syndrome, and variants in CLCNKB result in classical Bartter syndrome. Although all variants impair TAL electrolyte transport, their effects on mineral handling differ. In contrast to antenatal forms, classical Bartter syndrome is frequently associated with hypomagnesemia, a feature also found in Gitelman syndrome resulting from pathogenic variants in SLC12A3, expressed in the distal convoluted tubule (DCT). The mechanisms underlying these distinct clinical phenotypes are not understood. METHODS:Clcnkb- and Slc12a3-deficient mice as well as human kidneys were investigated. The abundance and localization of electrolyte and mineral transporters and stereological parameters were assessed by immunohistochemistry. Gene and protein expression was determined in Clcnkb-deficient mice. RESULTS:In human kidney, both ClC-K channels and their essential subunit Barttin were found in TAL, DCT, and collecting system. Clcnkb-deficient mice showed complete ablation of Clcnkb and reduced DCT and connecting tubule volumes. Furthermore, DCT magnesium channels and select basolateral magnesium transporters were markedly reduced in Clcnkb-deficient mice, similar to Slc12a3-deficient mice. In contrast, the overall abundance of calcium transport proteins was largely preserved. CONCLUSION:ClC-K channels are expressed in the TAL and DCT in mouse and human kidneys. Clcnkb ablation reduces TRPM magnesium channel expression and DCT tubule volume, providing a likely explanation for the frequently observed hypomagnesemia in classical Bartter syndrome.
AIM:Patients with chronic kidney disease (CKD) have an increased cardiovascular risk. Since neutrophils and neutrophil-borne proteins contribute to cardiovascular disease, we analyzed the neutrophil phenotype in patients with CKD who presented with a spectrum of cardiovascular comorbidities. METHODS:Blood from two independent cohorts of male patients with moderate to advanced CKD recruited through the cardiology or nephrology unit was analyzed for neutrophils maturation and activation markers using flow cytometry compared to healthy controls. The formation of neutrophil-extracellular traps was assessed using isolated neutrophils. Plasma levels of neutrophil-borne proteins (neutrophil elastase, myeloperoxidase, and S100A8/A9), plasma inflammatory markers and cardiovascular disease characteristics were compared. RESULTS:Both cohorts of CKD patients showed reduced neutrophil surface expression of maturation marker CD10 and higher plasma levels of myeloperoxidase compared to controls. No significant differences were observed in neutrophil surface activation markers in either baseline or stimulated conditions, or in the formation of neutrophil extracellular traps ex vivo. Although CKD patients presented with variable degrees of systemic inflammation and cardiovascular comorbidities, the immature neutrophil phenotype (low CD10) was not associated with either inflammatory status (CRP, IL6) or NT-proBNP levels. CONCLUSION:Male cardiorenal patients with moderate to advanced CKD do not show altered neutrophil surface activation markers or ex vivo activation potential per se. Yet, they display a more immature neutrophil phenotype and higher circulating neutrophil-borne myeloperoxidase as observed across a range of systemic inflammation degrees. This could potentially contribute to the overall increased cardiovascular risk in CKD.
In the 21st century, neuroglial research has entered a period of Renaissance, extending the views of prominent neuroanatomists and neurologists of the 19th and early 20th centuries, who assigned to glial cells numerous physiological functions and highlighted their fundamental role in the pathophysiology of nervous system diseases. Astrocytes are highly diversified in structure and function; they control brain homeostasis, support synaptic connectivity, and enable information processing in neural networks. Evolutionary diversification of astrocytes, initially emerging as supportive cells of primitive sensory organs, drove a continuous expansion of astroglial complexity and functional versatility, ultimately making them indispensable neuroprotectors and homeostatic regulators. The large, morphologically elaborate astrocytes of the human brain arguably reflect an evolutionary response to increased neuronal homeostatic demands. Astrocytes are indispensable for synaptic function, serving as the principal regulators of neurotransmitter turnover and neuronal excitability. Astrocytes also govern brain energy metabolism, mitochondrial dynamics, and calcium signaling, thereby actively shaping cortical plasticity and circuits. Astrocytes are fundamental elements of the pathophysiology of neurological, neuropsychiatric, and neurodegenerative diseases, including Alzheimer's and Parkinson's disease, amyotrophic lateral sclerosis, Rett syndrome, genetic astrocytopathies, and neurotrauma, where they demonstrate complex reactive changes directed at tissue preservation and regeneration, but which can also contribute to disease progression. Advances in single-cell transcriptomics, calcium imaging, chemogenetics, and iPSC-based models have transformed our understanding of astrocyte diversity and disease-specific dysfunction, opening new avenues of investigation. Given that no CNS disorder is known to occur without astrocyte involvement, multiple astrocyte-specific molecules represent compelling targets for cell-directed therapeutic strategies.
In the central nervous system (CNS), the tissue microenvironment is continuously monitored and regulated to secure the unobstructed function of neurons and of their networks. This is a key function of the neurovascular niche (NVN), which is the interface between the cells of the nervous tissue and the cells and the content of blood vessels. It is enabled by the Blood-Brain Barrier, a structure formed by endothelial and perivascular cells, extracellular matrix, and astrocytes, and is manifested by the limited surveillance of the CNS from blood-derived cells. Multiple sclerosis (MS) is a devastating degenerative disorder, in which the myelin sheaths that enwrap neuronal axons are destroyed, leading, over time, to neurological symptoms. MS has a strong immunological component which is targeted in most of the current disease-modifying treatments. Nevertheless, regenerative interventions aiming at enhancing and restoring the endogenous remyelination potential of the CNS, driven by the abundant Oligodendrocyte Progenitor Cells (OPCs), have not been successfully developed so far. Here, we will review key information on the structure of the NVN, and we will summarize the evidence on the role of inflammation in the emergence and the progress of MS, with a focus on the active response of OPCs. We will also present recent experimental evidence on the role of less investigated cellular elements of the NVN, such as pericytes and platelets, in the regulation of OPCs. Finally, we will discuss current and future treatments for MS.
Acute kidney injury (AKI) is a global health problem due to its high and increasing incidence, morbidity and mortality. Despite progress in understanding its pathophysiology, there are currently no pharmacological therapies that improve survival, limit damage, or accelerate recovery, except for supportive interventions and renal replacement therapies. Cumulative knowledge indicates that during AKI, the dynamic balance between the two arms of renin-angiotensin system (RAS) is disturbed, activating the classical and reducing the protective arm. This imbalance determines pathophysiological outcomes, so the modulation of protective arm emerges as a key therapeutic strategy. This arm offers several pharmacological targets such as angiotensin II type 2 receptor (AT2R), angiotensin converting enzyme 2 (ACE2), angiotensin (1-7) and its receptor Mas (MasR), and alamandine and its receptor, Mas-related G protein-coupled receptor D (MrgD). This review presents current evidence on the modulation of the protective arm of the RAS, its role in AKI pathophysiology, and its potential as a therapeutic target, presenting literature-based evidence that such modulation exerts beneficial effects in experimental models of ischemia-reperfusion, septic and nephrotoxic AKI. This evidence emphasizes the potential of these targets for drug development in the context of AKI. Further investigation of this RAS axis may expand our understanding of AKI pathophysiology and open new avenues for the development of targeted, effective, and safer therapeutic strategies.
MicroRNAs (miRNAs) have emerged as central regulators of pancreatic islet biology, influencing β-cell development, proliferation, and function. In type 2 diabetes (T2D), both adaptive and maladaptive miRNA responses shape β-cell compensation and progressive secretory dysfunction. Here, we review current insights into the regulation of insulin secretion, with a focus on exocytosis and the autocrine and paracrine regulation of β-cells, and discuss the involvement of miRNAs in these processes. We describe miRNA biogenesis and the regulation of miRNAs in β-cells, focusing on glucose- and cAMP-responsive miRNAs and epigenetic control. We summarize mechanistic evidence linking individual miRNAs to the regulation of β-cell function during T2D development, including effects on metabolic signaling and the exocytotic machinery, and compare results from humans, rodents, and cell lines, while emphasizing both the need for and difficulties of performing these investigations in β-cells from human donors. Moreover, recent network-level analyses reveal that T2D is characterized not by isolated miRNA changes but by coordinated changes in miRNA-mRNA regulatory pathways that converge on reduced and/or compensatory insulin secretion. Beyond cell-intrinsic actions, we discuss how circulating miRNAs transported via extracellular vesicles (EVs) mediate crosstalk between β-cells and peripheral tissues, influencing insulin resistance, β-cell function, and systemic glucose homeostasis. Finally, we highlight the potential of circulating miRNAs as diagnostic and predictive biomarkers, as well as the use of EVs and miRNAs for therapeutic applications, while underscoring the technical challenges that currently limit clinical translation. Nevertheless, advances in technical, network, and inter-organ analyses position miRNAs as promising biomarkers and therapeutic targets in T2D.
Maintenance of potassium (K+) homeostasis across cell membranes is essential for life. While systemic K+ balance is primarily regulated by the kidneys and intestines, ion channels, pumps, and transporters govern K+ movement across epithelial barriers at the cellular level. Despite the prevalence of diseases caused by disrupted K+ homeostasis, the role of K+ channels in the lungs has received comparatively little attention. The airway epithelium expresses a diverse array of K+ channels that regulate key functions such as transepithelial ion transport, ciliary beating, and mucus secretion. These processes are fundamental components of mucociliary clearance (MCC), the primary innate defense mechanism of the lungs. Dysfunction of MCC is central to muco-obstructive diseases, including cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD), and asthma. While K+ channels were once considered therapeutic targets for enhancing anion secretion in CF, initial interest waned. However, it has been reinvigorated by recent findings showing that drugs targeting CFTR can also modulate airway epithelial K+ channels and facilitate MCC. In this review, we compile current evidence on targeting K+ channels to treat muco-obstructive diseases. We discuss therapeutic opportunities offered by K+ channel modulators, highlight emerging functions of these channels in the airways, and outline priorities for future research.
ABSTRACT Introduction In physoclist fish, that is, in fish with a closed swimbladder, oxygen has been shown to be the main gas in the swimbladder. Gas gland cells, crucial for the filling of the swimbladder, produce and secrete lactic acid. The resulting acidification of the blood releases oxygen from the hemoglobin via the Root effect, generating high oxygen partial pressures required for the diffusion of oxygen into the swimbladder. CO 2 in swimbladder gas was believed mainly to result from a wash out of HCO 3 − from the plasma due to acidification, but this reaction would diminish blood acidification. This study therefore attempted to revisit our current information about CO 2 production and also about CO 2 and HCO 3 − movements in swimbladder tissue to elucidate the role of CO 2 for swimbladder function. Methods Targeted literature search has been conducted to search for relevant publications. Results The data reveal that European eel Anguilla anguilla gas gland cells produce most of the CO 2 in the pentose phosphate shunt. CO 2 diffuses into the swimbladder lumen and into the blood, facilitated by aquaporin 1. Membrane‐bound carbonic anhydrase together with HCO 3 − transporters allow for CO 2 and HCO 3 − cycling across the basolateral gas gland cell membrane, supporting proton secretion and blood acidification. Countercurrent concentration of CO 2 , HCO 3 − and protons in the rete mirabile results in a significant acidification of arterial blood in the rete. Conclusions CO 2 production together with CO 2 and HCO 3 − movements in swimbladder tissue significantly support blood acidification and the generation of high oxygen as well as CO 2 partial pressures.
OBJECTIVES:Human islets are widely researched to understand pathophysiological mechanisms leading to diabetes. Sex, age, and body mass index (BMI) are key donor traits influencing islet function, which is also regulated by an intricate network of microRNAs. METHODS:Here, we profiled 754 microRNAs and 58 191 gene transcripts (19 919 protein-coding) in up to 131 different human islet donor preparations (without diabetes) and assessed their association with donor traits. Additionally, the effect of the age-associated key microRNAs on relative telomere length in human islet-derived cells was evaluated. RESULTS:MicroRNA discovery analyses identified miR-199a-5p and miR-214-3p to be associated (adjusted p-value ≤ 0.05) with all three traits (i.e., sex, age, and BMI); miR-147b-3p with sex and age; miR-378a-5p with sex and BMI; miR-542-3p, miR-34a-3p, miR-34a-5p, miR-497-5p and miR-99a-5p with age and BMI. After adjusting for covariates, 612 protein-coding gene transcripts associated with sex (excluding those from sex-chromosomes), 902 with age, and 250 with BMI. MicroRNA-199a-5p and miR-214-3p levels negatively correlated with mRNAs critical in islet function, metabolic regulation, and senescence. In vitro validation studies verified that inhibition of two common microRNAs (miR-199a-5p/-214-3p) slowed down telomere length shortening in human islet-derived cells. CONCLUSIONS:Our analyses identify human islet microRNAs associated with donor traits and provide evidence that these microRNAs can potentially modulate cellular aging phenotype (reflected by relative telomere length) in human islet-derived cells.
Mouse models are widely used to study heat-related physiological responses as they provide insights relevant to human health. However, species differences (including nocturnal behavior) and standard housing below the thermoneutral zone (TNZ; 26°C-34°C) can confound comparisons. This systematic review evaluates methodologies, including housing temperatures, used in mouse heat-exposure studies published over the past 4 years. Medline, Web of Science, and Embase were searched for peer-reviewed mouse heat-exposure studies published from 2020 to 10 January 2025. Data on housing temperature, heat-exposure protocols, and physiological outcomes were extracted. Screening and extraction were conducted independently and in duplicate in Covidence. One hundred seventy studies were included. Of those, 142 (83%) housed control mice below TNZ; seven (4%) studies maintained TNZ conditions and the remainder did not report control temperature. Heat exposures ranged from 30°C-45°C, most commonly 39°C-41°C. Body temperature was measured in 110 (65%) studies, often targeting ~42°C. When timing was reported, exposures occurred mainly during the light phase (52, 30%). Most studies used males only (116, 68%); 31 (18%) used females only; 9 (5%) included both sexes; and 14 (8%) did not report sex. Common outcomes were digestive (55, 32%), inflammatory (47, 28%), and central nervous system (40, 24%). Recent mouse heat-exposure studies often compare heat-exposed animals with cold-stressed controls and apply daytime exposures that conflict with the nocturnal behavior of mice and human diurnal pattern. Incomplete reporting of housing conditions limits interpretation. Future research should account for differences between mice and humans to improve translational relevance. Trial Registration: PROSPERO: CRD42024611316.
AIM:Kidney excretion of phosphate is the gatekeeper of systemic phosphate homeostasis as evident from inborn and acquired diseases. Renal phosphate transporters are a promising target for phosphate-lowering drugs, but molecular details of human kidney phosphate handling are largely unknown. Here, we aim to understand the dependency of renal phosphate transport on species, age, and sex. METHODS:We used a combination of transporter-specific inhibitors and radioactive flux measurements in isolated BBM vesicles prepared from human and murine kidneys. We included human female and male neonates (0-11 months) and adults (51-63 years) and age-matched mouse kidneys. Immunoblotting and immunofluorescence detected transport protein expression, and transcript expression was analyzed in publicly available data. FINDINGS:The flux experiments revealed that in human kidneys SLC34A1, SLC34A2/3 and other non-SLC34 transporter are active and expressed with age- and sex-dependent differences. In mice about 80% of renal phosphate handling depends on Slc34a1, but in humans SLC34A1 contribution is 60% in neonates and only 40% in adults. SLC34A3 contribution accounts for 20% in human neonates and 40% in human adults but is almost negligible in mice. Non SLC34 sodium-dependent phosphate transport was around 20% in all groups. SCRNA-seq data and immunoblotting analysis revealed differences in sodium cotransporters between species that supported the activity measurements. CONCLUSION:Our data provide the first direct measurement of sodium-phosphate cotransporter activities in human kidney and show profound differences between species. These results are critical when developing novel drugs to modulate renal phosphate reabsorption.
Transepithelial calcium absorption occurs via a transcellular or paracellular pathway. The intestinal transcellular pathway relies, at least partially, on the apical calcium channel transient receptor potential vanilloid 6 (TRPV6), whereas paracellular calcium (re)absorption occurs through tight junction proteins, including claudin-2 (CLDN2). Both CLDN2 and TRPV6 are also expressed in the kidney. CLDN2 contributes to proximal tubular calcium reabsorption, whereas the functional relevance of TRPV6 remains unclear. Cldn2-/- knockout mice exhibit reduced intestinal calcium permeability and hypercalciuria, while maintaining normal bone mineral density (BMD), plasma calcium, and calciotropic hormone levels. Trpv6D541A/D541A pore mutants were reported to have normal urinary and plasma calcium levels, despite reduced intestinal calcium absorption on a low calcium diet. However, we found subtle sex-specific differences in calcium homeostasis in these mice. We hypothesized that transcellular and paracellular calcium absorption pathways compensate for one another in these models. To test this, we crossed Cldn2-/- with Trpv6D541A/D541A mice to generate a functional double knockout (DKO, Cldn2-/-/Trpv6D541A/D541A). These mice displayed hypocalcemia, elevated calcitriol, and reduced BMD. Surprisingly, despite unchanged fecal calcium excretion, renal calcium wasting was greater than in Cldn2-/- mice. Gene expression studies revealed increased calbindin-D9k expression in the proximal colon and calbindin-D28k in the kidney, consistent with partial compensation by the colon and distal nephron. Together, these findings indicate that combined impairment of paracellular and transcellular calcium transport reduces intestinal and renal calcium (re)absorption, leading to hypocalcemia and increased calcitriol levels, and highlight a role for TRPV6 in distal nephron calcium handling.
AIM:Cardiac remodeling (CR) is a critical risk factor for the development and progression of cardiovascular diseases. CR is accompanied by activation of the innate immune response, with NLRP3 inflammasome emerging as a key player in morphological and functional changes. However, the mechanisms underlying NLRP3 inflammasome assembly and activation in the heart upon beta-adrenergic overactivation remain poorly understood. This study aims to investigate the temporal profile of NLRP3 inflammasome activation and its upstream signaling P2X7-NEK7 in isoproterenol (ISO)-induced CR. METHODS:Wild-type (WT), NLRP3 knockout (NLRP3-KO), and P2X7-KO male mice were treated with ISO (60 mg/kg) for 1 h, 12 h, 24 h, or 14 days. Cardiac function was assessed by echocardiography and plethysmography. Cardiac hypertrophy and fibrosis were evaluated by histology. Fibrosis markers and cytokines gene expression were analyzed by quantitative PCR. Protein expression was evaluated by Western Blotting. Inflammasome assembly was confirmed by ASC speck immunofluorescence. RESULTS:WT mice showed a rapid activation of NLRP3 inflammasome in the heart up to 12 h from ISO administration, evidenced by increased NLRP3, ASC speck, Caspase-1, and IL-1β. ISO treatment for 12 h also increased P2X7 and NEK7. NLRP3-KO mice were protected from ISO-induced fibrosis and impairment of LV relaxation as well as the Caspase-1 activation and cytokines production. NEK7, NLRP3 activation, and fibrosis were prevented in P2X7-KO. NLRP3 deletion did not affect ISO-induced cardiac hypertrophy. CONCLUSION:These findings suggest that the NLRP3 inflammasome is activated by the P2X7-NEK7 pathway in the early stage of beta-adrenergic insult, driving ISO-induced cardiac fibrosis and inflammation.
