Aquaporin-1 Deficiency Protects Against Myocardial Infarction by Reducing Both Edema and Apoptosis in Mice

The impact of X-rays on cardiac hydrometabolism and the regulatory role of AS-IV

BACKGROUND

Radiation-induced cardiac injury has emerged as a significant pathological entity, with many studies focusing on the fibrotic changes in myocardial tissue. However, these do not offer solutions for the clinical prevention and treatment of radiation-induced heart disease. Regulating hydrometabolism presents a potential therapeutic target for the management of cardiovascular diseases. This research seeks to explore the impacts of irradiation on cardiac hydrometabolism and its regulatory mechanisms.

METHODS

The impact of X-ray radiation on cardiac and cardiomyocyte hydrometabolism was studied through in vivo and in vitro experiments, examining the pharmacological effects and mechanisms of PX-478 and AS-IV interventions in cardiomyocytes.

RESULTS

28 days after direct chest irradiation with 20 Gy X-rays, C57BL/6 mice exhibited an increased heart wet-to-dry weight ratio, significant enlargement of cardiomyocyte cross-sectional area, and elevated protein expression of HIF-1α, AQP1, AQP4, Cx43, Caspase3, and Bax, with decreased expression of Bcl-2. Irradiation with 6 Gy X-rays induced edema and damage in AC16 and HL-1 cardiomyocytes at 24, 48, and 72 h, with increased expression of HIF-1α, AQP1, AQP4, and Cx43 proteins post-radiation. Inhibition of HIF-1α ameliorated edema and apoptosis in AC16 and HL-1 cardiomyocytes, reducing the expression of HIF-1α, AQP1, AQP4, and Cx43 proteins. AS-IV demonstrated strong binding affinity with HIF-1α, and successfully attenuated the expression levels of HIF-1α, AQP1, AQP4, and Cx43 proteins, alleviating edema, mitochondrial swelling, and apoptosis in AC16 and HL-1 cardiomyocytes. Furthermore, AS-IV improved cardiomyocyte edema by restoring the activity of Na/K-ATPase.

CONCLUSION

Aberrant activation of the HIF-1α/AQPs/Cx43 axis is a key mechanism in X-ray-induced cardiomyocyte edema and damage. AS-IV can ameliorate X-ray induced cardiac damage by regulating hydrometabolism.

Important functions and molecular mechanisms of aquaporins family on respiratory diseases: potential translational values

Aquaporins (AQPs) are a subgroup of small transmembrane transporters that are distributed in various types of tissues, including the lung, kidney, heart and central nervous system. It is evident that respiratory diseases represent a significant global health concern, with a considerable number of deaths occurring worldwide. Recent researches have demonstrated that AQPs play a pivotal role in respiratory diseases, including chronic obstructive pulmonary disease (COPD), asthma, acute respiratory distress syndrome (ARDS), and particularly non-small cell lung cancer (NSCLC). In the context of NSCLC, the overexpression of AQP1, AQP3, AQP4, and AQP5 has been demonstrated to facilitate tumor angiogenesis, as well as the proliferation, migration, and invasiveness of tumor cells. This review concisely explores the role of AQP family on respiratory diseases, to assess their clinical and translational significance for understanding molecular pathogenesis. However, the potential translation of AQPs biomarkers into clinical applications is promising and the understanding of the precise mechanisms influencing respiratory diseases is still ongoing. Addressing the challenges and outlining the future perspectives in AQPs development is essential for clinical progress in a concise manner.

Diabetic Cardiomyopathy: Role of Cell Death, Exosomes, Fibrosis and Epicardial Adipose Tissue

Diabetic cardiomyopathy (DCM) represents one of the typical complications associated with diabetes. It has been described as anomalies in heart function and structure, with consequent high morbidity and mortality. DCM development can be described by two stages; the first is characterized by left ventricular hypertrophy and diastolic dysfunction, and the second by heart failure (HF) with systolic dysfunction. The proposed mechanisms involve cardiac inflammation, advanced glycation end products (AGEs) and angiotensin II. Furthermore, different studies have focused their attention on cardiomyocyte death through the different mechanisms of programmed cell death, such as apoptosis, autophagy, necrosis, pyroptosis and ferroptosis. Exosome release, adipose epicardial tissue and aquaporins affect DCM development. This review will focus on the description of the mechanisms involved in DCM progression and development.

Blood-nerve barrier enhances chronic postsurgical pain via the HIF-1α/ aquaporin-1 signaling axis

BACKGROUND

Blood nerve barrier (BNB) participates in the development of neuropathic pain. AQP1 is involved in peripheral pain perception and is negatively correlated with HIF-1α phenotype, which regulates endothelial permeability. However, the role of HIF-1α-AQP1-mediated BNB dysfunction in Chronic Postsurgical Pain (CPSP) has not been reported.

METHODS

Male Sprague-Dawley rats were randomized into 5 groups: (i) Naive group; (ii) Sham group; (iii) SMIR group: skin/muscle incision and retraction for one hour. Behavioral tests were performed for the three groups, BNB vascular permeability and western blotting were conducted to determine HIF-1α and AQP1 protein expression. (iv) The SMIR + HIF-1α inhibitor group; (v) SMIR + DMSO group. Rats in the two groups were administered with HIF-1α inhibitor (2ME2) or DMSO intraperitoneally on the third day post-SMIR surgery followed by performance of behavioral tests, BNB permeability assessment, and determination of HIF-1α, AQP1 and NF200 protein levels.

RESULTS

The permeability of BNB was significantly increased and the expression of AQP1 was downregulated on the 3rd and 7th days post-operation. AQP1 is mainly located in neurons and NF200, CGRP-positive nerve fibers. HIF-1α was highly expressed on the third day post-operation. HIF-1α inhibitor reversed the decrease in AQP1 expression and increase in NF200 expression, barrier permeability and hyperalgesia induced by SMIR on the 3rd day post-surgery.

CONCLUSIONS

Early dysfunction of BNB mediated by HIF-1α/AQP1 activated by SMIR may be an important mechanism to promote acute postoperative painful transformation of CPSP. Preadaptive protection of endothelial cells around nerve substructures may be an important countermeasure to inhibit CPSP transformation. Early impairment of BNB function mediated by HIF-1α/AQP1 activated by SMIR may be an important mechanism for promoting acute postoperative pain transformation of CPSP.

XinLi formula, a traditional Chinese decoction, alleviates chronic heart failure via regulating the interaction of AGTR1 and AQP1

BACKGROUND

XinLi formula (XLF) is a traditional Chinese medicine used in clinical practice to treat chronic heart failure (CHF) in humans, with remarkable curative effect. However, the mechanism remains unknown.

PURPOSE

The goal of the current investigation was to determine how XLF affected CHF in a rat model of the condition brought on by ligation of the left anterior descending coronary artery, and to investigate the underlying mechanism.

STUDY DESIGN AND METHODS

Cardiac function was detected by echocardiography. The contents of myocardial enzymes, Ang II, ALD, TGF-β1, and inflammatory factors were measured by ELISA. Myocardial injury and myocardial fibrosis were evaluated by HE and Masson staining. Myocardial edema was assessed by cardiac mass index and transmission electron microscopy. Using Western blot and immunohistochemistry to examining the protein expression of inflammasome, TGF-β1, AGTR1, and AQP1 in the left ventricle. Furthermore, the interaction of AGTR1 and AQP1 was evaluated by co-immunoprecipitation.

RESULTS

XLF attenuated myocardial enzymes and myocardial injury, and improved cardiac function in rats with CHF after myocardial infarction. It also reduced Ang II and ALD levels in CHF rats, and suppressed the expression of AGTR1 and TGF-β1, finally alleviated myocardial fibrosis. By mechanism, XLF inhibited the expression of NLRP3 inflammasome proteins, reduced the plasma contents of IL-1β, IL-18, IL-6 and TNF-α. Additionally, XLF inhibited the expression of AQP1 and the interaction of AGTR1 and AQP1, alleviating myocardial edema. The common structure of the main chemical constituents of XLF were glycoside compounds with glycosyl.

CONCLUSION

XLF ameliorated CHF, which was evidenced by the alleviation of myocardial fibrosis by inhibiting AGTR1/NLRP3 signal, as well as the attenuation of myocardial edema by suppressing the interaction of AGTR1 and AQP1.

Transcriptomic Profiling Unravels Novel Deregulated Gene Signatures Associated with Acute Myocardial Infarction: A Bioinformatics Approach

Acute myocardial infarction (AMI) is a severe disease with elevated morbidity and mortality rate worldwide. This is attributed to great losses of cardiomyocytes, which can trigger the alteration of gene expression patterns. Although several attempts have been made to assess the AMI biomarkers, to date their role in rescuing myocardial injury remains unclear. Therefore, the current study investigated three independent microarray-based gene expression datasets from AMI patients (n = 85) and their age-sex-matched healthy controls (n = 70), to identify novel gene signatures that might be involved in cardioprotection. The differentially expressed genes (DEGs) were analyzed using 'GEO2R', and weighted gene correlation network analysis (WGCNA) was performed to identify biomarkers/modules. We found 91 DEGs, of which the number of upregulated and downregulated genes were 22 and 5, respectively. Specifically, we found that the deregulated genes such as ADOR-A3, BMP6, VPS8, and GPx3, may be associated with AMI. WGCNA revealed four highly preserved modules among all datasets. The 'Enrichr' unveiled the presence of miR-660 and STAT1, which is known to affect AMI severity. Conclusively, these genes and miRNA might play a crucial role the rescue of cardiomyocytes from severe damage, which could be helpful in developing appropriate therapeutic strategies for the management of AMI.

Aquaporins: Important players in the cardiovascular pathophysiology

Aquaporin is a membrane channel protein widely expressed in body tissues, which can control the input and output of water in cells. AQPs are differentially expressed in different cardiovascular tissues and participate in water transmembrane transport, cell migration, metabolism, inflammatory response, etc. The aberrant expression of AQPs highly correlates with the onset of ischemic heart disease, myocardial ischemia-reperfusion injury, heart failure, etc. Despite much attention to the regulatory role of AQPs in the cardiovascular system, the translation of AQPs into clinical application still faces many challenges, including clarification of the localization of AQPs in the cardiovascular system and mechanisms mediating cardiovascular pathophysiology, as well as the development of cardiovascular-specific AQPs modulators.Therefore, in this study, we comprehensively reviewed the critical roles of AQP family proteins in maintaining cardiovascular homeostasis and described the underlying mechanisms by which AQPs mediated the outcomes of cardiovascular diseases. Meanwhile, AQPs serve as important therapeutic targets, which provide a wide range of opportunities to investigate the mechanisms of cardiovascular diseases and the treatment of those diseases.

MicroRNA-155 inhibition attenuates myocardial infarction-induced connexin 43 degradation in cardiomyocytes by reducing pro-inflammatory macrophage activation

BACKGROUND

Degradation of pro-inflammatory macrophage-mediated connexin 43 (Cx43) plays an important role in post-myocardial infarction (MI) arrhythmogenesis, microRNA (miR)-155 produced by macrophages has been shown to mediate post-MI effects. We hypothesized that miR-155 inhibition attenuated MI-induced Cx43 degradation by reducing pro-inflammatory macrophage activation.

METHODS

MI was induced by permanent ligation of the left anterior descending coronary artery in male C57BL/6 mice. Lipopolysaccharide (LPS)-stimulated mice bone marrow-derived macrophages (BMDMs) and hypoxia-induced neonatal rat cardiomyocytes (NRCMs) were used in vitro models. qRT-PCR, Western-blot and immunofluorescence were used to analyze relevant indicators.

RESULTS

The expression levels of miR-155, interleukin-1 beta (IL-1β), and matrix metalloproteinase (MMP)7 were higher in MI mice and LPS-treated BMDMs than in the sham/control groups, treatment with a miR-155 antagomir reversed these effects. Moreover, miR-155 inhibition reduced ventricular arrhythmias incidence and improved cardiac function in MI mice. Cx43 expression was decreased in MI mice and hypoxia-exposed NRCMs, and hypoxia-induced Cx43 degradation in NRCMs was reduced by application of conditioned medium from LPS-induced BMDMs treated with the miR-155 antagomir, but increased by conditioned medium from BMDMs treated with a miR-155 agomir. Importantly, NRCMs cultured in conditioned medium from LPS-induced BMDMs transfected with small interfering RNA against IL-1β and MMP7 showed decreased hypoxia-mediated Cx43 degradation, and this effect also was diminished by BMDM treatment with the miR-155 agomir. Additionally, siRNA-mediated suppressor of cytokine signaling 1 (SOCS1) knockdown in LPS-induced BMDMs promoted Cx43 degradation in hypoxia-exposed NRCMs, and the effect was reduced by the miR-155 inhibition.

CONCLUSIONS

MiR-155 inhibition attenuated post-MI Cx43 degradation by reducing macrophage-mediated IL-1β and MMP7 expression through the SOCS1/nuclear factor-κB pathway.

Signaling Mechanisms and Pharmacological Modulators Governing Diverse Aquaporin Functions in Human Health and Disease

The aquaporins (AQPs) are a family of small integral membrane proteins that facilitate the bidirectional transport of water across biological membranes in response to osmotic pressure gradients as well as enable the transmembrane diffusion of small neutral solutes (such as urea, glycerol, and hydrogen peroxide) and ions. AQPs are expressed throughout the human body. Here, we review their key roles in fluid homeostasis, glandular secretions, signal transduction and sensation, barrier function, immunity and inflammation, cell migration, and angiogenesis. Evidence from a wide variety of studies now supports a view of the functions of AQPs being much more complex than simply mediating the passive flow of water across biological membranes. The discovery and development of small-molecule AQP inhibitors for research use and therapeutic development will lead to new insights into the basic biology of and novel treatments for the wide range of AQP-associated disorders.

Compound Danshen Dripping Pill inhibits high altitude-induced hypoxic damage by suppressing oxidative stress and inflammatory responses

CONTEXT

Previous studies indicate that compound Danshen Dripping Pill (CDDP) improves the adaptation to high-altitude exposure. However, its mechanism of action is not clear.

OBJECTIVE

To explore the protective effect of CDDP on hypobaric hypoxia (HH) and its possible mechanism.

MATERIALS AND METHODS

A meta-analysis of 1051 human volunteers was performed to evaluate the effectiveness of CDDP at high altitudes. Male Sprague-Dawley rats were randomized into 5 groups (n = 6): control at normal pressure, model, CDDP-170 mg/kg, CDDP-340 mg/kg and acetazolamide groups. HH was simulated at an altitude of 5500 m for 24 h. Animal blood was collected for arterial blood-gas analysis and cytokines detection and their organs were harvested for pathological examination. Expression levels of AQP1, NF-κB and Nrf2 were determined by immunohistochemical staining.

RESULTS

The meta-analysis data indicated that the ratio between the combined RR of the total effective rate and the 95% CI was 0.23 (0.06, 0.91), the SMD and 95% CI of SO₂ was 0.37 (0.12, 0.62). Pre-treatment of CDDP protected rats from HH-induced pulmonary edoema and heart injury, left-shifted oxygen-dissociation curve and decreased P50 (30.25 ± 3.72 vs. 37.23 ± 4.30). Mechanistically, CDDP alleviated HH-reinforced ROS by improving SOD and GPX1 while inhibiting pro-inflammatory cytokines and NF-κB expression. CDDP also decreased HH-evoked D-dimer, erythrocyte aggregation and blood hemorheology, promoting AQP1 and Nrf2 expression.

DISCUSSION AND CONCLUSIONS

Pre-treatment with CDDP could prevent HH-induced tissue damage, oxidative stress and inflammatory response. Suppressed NF-κB and up-regulated Nrf2 might play significant roles in the mechanism of CDDP.

Exploring the role of Aquaporins (AQPs) in LPS induced systemic inflammation and the ameliorative effect of Garcinia in male Wistar rat

The Aquaporins (AQPs) could prove to be striking targets of inflammation. The aim of this study was to study the involvement of AQPs and explore the anti-inflammatory activity of Garcinia extract in LPS induced acute systemic inflammation in Wistar rats. Adult male Wistar rats (n = 6) were pretreated with Garcinia orally twice for 7 days, followed by a single intraperitoneal dose (5.5 mg/kgbw) of LPS. Serum ALT, AST, ALP, Creatinine, Urea and BUN, nitric oxide, prostaglandin, cytokine and chemokine levels were measured. LC-MS analysis of Garcinia was performed to identify the phytoconstituents present. The iNOS and COX enzyme activity were determined in the target tissues. qPCR analysis of inos, cox-2 and aqps was performed. Relative protein expression of AQPs was studied by Western blot analysis. Molecular docking studies were performed to study the interaction of garcinol and hydroxycitric acid, the two important phytoconstituents of Garcinia with AQP. The qPCR analysis showed tissue-specific up-regulation of aqp1, aqp3, aqp4 and aqp8 in LPS induced rats. Garcinia extract treatment effectively lowered the mRNA expression of these AQPs. Garcinia extract significantly inhibited the LPS-induced NO, prostaglandin, cytokine and chemokine production in serum and also decreased tissue-specific transcript level of inos and cox-2, thus suggesting the anti-inflammatory role of Garcinia. Also, docking studies revealed interactions of garcinol and hydroxycitric acid with AQP1, 3, 4 and 8. Therefore, the present study suggests the possible involvement of AQP1, 3, 4 and 8 in inflammation and the efficacy of Garcinia extract as an anti-inflammatory agent. Therefore, AQPs can act as prognostic markers of inflammation and can be targeted with Garcinia extract.

Testicular AQP1 expression in a rat model of testicular Ischemia-Reperfusion injury

Aquaporin 1 (AQP1) is the archetype of all aquaporins and involved in rapid cellular water fluxes and cell volume regulation.

AN OBJECTIVE

This study was conducted for the investigation of AQP1 expression in normal testicular tissues and those with I/R injury in a rat model.

STUDY DESIGN

A TT rat model was established using male Wister rats (4 weeks old, 180-220 g), and AQP1 distribution in the testicular tissues was detected by immunohistochemistry. The wet/dry (W/D) weight ratios of the testes were determined at 12 h, 24 h, 36 h, 48 h, or 5 days after the establishment of the TT model. At each time point, pathological sections were prepared and the mRNA and protein expression levels of AQP1 were determined by RT-qPCR and Western blotting, respectively.

RESULTS

Immunohistochemical staining indicated that AQP1 distributes in testicular vascular endothelial cells and interstitial connective tissues. The testicular edema was observed 12 and 24 h after TT, as indicated by the increase in wet/dry weight ratio and pathological changes, such as enlarged testicular interstitium, atrophy of spermatogenic tubules, and epineurium tubule exfoliation. Increase in the expression levels of Aqp1 mRNA and AQP1 protein levels peaked at 24 h. Edema was alleviated at 36 and 48 h, as manifested by the gradual thinning of the spermatogenic tubules epithelium with narrowed interstitium and weakened inflammatory cell infiltration. Meanwhile, the mRNA and protein levels of AQP1 dramatically decreased. At 5 days after TT, edema was nearly absent, and the mRNA and protein levels of AQP1 were restored to basal levels.

DISCUSSION

Testicular torsion increases AQP1 expression and W/D ratios in testis tissues. The upregulation of AQP1 expression and decline in AQP1 level are consistent to the development and alleviation of edema in testis tissues that underwent testicular torsion.

CONCLUSION

Changes in AQP1 expression were consistent with edema severity in the testes, indicating a close relationship between the expression of AQP1 and the extent of edema in testicular I/R.

AQP1 Is Up-Regulated by Hypoxia and Leads to Increased Cell Water Permeability, Motility, and Migration in Neuroblastoma

The water channel aquaporin 1 (AQP1) has been implicated in tumor progression and metastasis. It is hypothesized that AQP1 expression can facilitate the transmembrane water transport leading to changes in cell structure that promote migration. Its impact in neuroblastoma has not been addressed so far. The objectives of this study have been to determine whether AQP1 expression in neuroblastoma is dependent on hypoxia, to demonstrate whether AQP1 is functionally relevant for migration, and to further define AQP1-dependent properties of the migrating cells. This was determined by investigating the reaction of neuroblastoma cell lines, particularly SH-SY5Y, Kelly, SH-EP Tet-21/N and SK-N-BE(2)-M17 to hypoxia, quantitating the AQP1-related water permeability by stopped-flow spectroscopy, and studying the migration-related properties of the cells in a modified transwell assay. We find that AQP1 expression in neuroblastoma cells is up-regulated by hypoxic conditions, and that increased AQP1 expression enabled the cells to form a phenotype which is associated with migratory properties and increased cell agility. This suggests that the hypoxic tumor microenvironment is the trigger for some tumor cells to transition to a migratory phenotype. We demonstrate that migrating tumor cell express elevated AQP1 levels and a hypoxic biochemical phenotype. Our experiments strongly suggest that elevated AQP1 might be a key driver in transitioning stable tumor cells to migrating tumor cells in a hypoxic microenvironment.

The Regulatory Role of Histone Modification on Gene Expression in the Early Stage of Myocardial Infarction

Myocardial infarction (MI) is a fatal heart disease with high morbidity and mortality. Various studies have demonstrated that a series of relatively specific biological events occur within 24 h of MI. However, the roles of histone modifications in this pathological process are still poorly understood. To investigate the regulation of histone modifications on gene expression in early MI, we performed RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) on myocardial tissues 24 h after the onset of MI. The genome-wide profiles of five histone marks (H3K27ac, H3K9ac, H3K4me3, H3K9me3, and H3K27me3) were explored through ChIP-seq. RNA-seq identified 1,032 differentially expressed genes (DEGs) between the MI and sham groups. ChIP-seq analysis found that 195 upregulated DEGs were modified by change of at least one of the three active histone marks (H3K27ac, H3K9ac, and H3K4me3), and the biological processes and pathways analysis showed that these DEGs were significantly enriched in cardiomyocyte differentiation and development, inflammation, angiogenesis, and metabolism. In the transcriptional regulatory network, Ets1, Etv1, and Etv2 were predicted to be involved in gene expression regulation. In addition, by integrating super-enhancers (SEs) with RNA-seq data, 76 DEGs were associated with H3K27ac-enriched SEs in the MI group, and the functions of these SE-associated DEGs were mainly related to angiogenesis. Our results suggest that histone modifications may play important roles in the regulation of gene expression in the early stage of MI, and the early angiogenesis response may be initiated by SEs.

Ions, the Movement of Water and the Apoptotic Volume Decrease

The movement of water across the cell membrane is a natural biological process that occurs during growth, cell division, and cell death. Many cells are known to regulate changes in their cell volume through inherent compensatory regulatory mechanisms. Cells can sense an increase or decrease in their cell volume, and compensate through mechanisms known as a regulatory volume increase (RVI) or decrease (RVD) response, respectively. The transport of sodium, potassium along with other ions and osmolytes allows the movement of water in and out of the cell. These compensatory volume regulatory mechanisms maintain a cell at near constant volume. A hallmark of the physiological cell death process known as apoptosis is the loss of cell volume or cell shrinkage. This loss of cell volume is in stark contrast to what occurs during the accidental cell death process known as necrosis. During necrosis, cells swell or gain water, eventually resulting in cell lysis. Thus, whether a cell gains or loses water after injury is a defining feature of the specific mode of cell death. Cell shrinkage or the loss of cell volume during apoptosis has been termed apoptotic volume decrease or AVD. Over the years, this distinguishing feature of apoptosis has been largely ignored and thought to be a passive occurrence or simply a consequence of the cell death process. However, studies on AVD have defined an underlying movement of ions that result in not only the loss of cell volume, but also the activation and execution of the apoptotic process. This review explores the role ions play in controlling not only the movement of water, but the regulation of apoptosis. We will focus on what is known about specific ion channels and transporters identified to be involved in AVD, and how the movement of ions and water change the intracellular environment leading to stages of cell shrinkage and associated apoptotic characteristics. Finally, we will discuss these concepts as they apply to different cell types such as neurons, cardiomyocytes, and corneal epithelial cells.

Changes in cardiac Aquaporin expression during aortic valve replacement surgery with cardiopulmonary bypass

OBJECTIVES

Cardiopulmonary bypass (CPB) use is an essential strategy for many cardiovascular surgeries. However, its use and duration have been associated with a higher rate of postoperative complications, such as low cardiac output syndrome due to myocardial oedema and dysfunction. Though Aquaporin water channels have been implicated in myocardial water balance, their specific role in this clinical scenario has not been established.

METHODS

In a consecutive study of 17 patients with severe aortic stenosis undergoing aortic valve replacement surgery, 2 myocardial biopsies of the left ventricle were taken: 1 before and 1 after CPB use. Sociodemographic, clinical and laboratory data were collected. Western blot and immunohistochemistry studies were performed.

RESULTS

After CPB use, there was a mean increase of ∼62% in Aquaporin 1 protein levels (P = 0.001) and a mean reduction of ∼38% in Aquaporin 4 protein levels (P = 0.030). In immunohistochemistry assays, Aquaporin 1 was found lining small blood vessels, while Aquaporin 4 formed a circular label in cardiomyocytes. There were no changes in the localization of either protein following CPB use. During the observed on-pump time interval, there was a 1.7%/min mean increase in Aquaporin 1 (P = 0.021) and a 2.5%/min mean decrease in Aquaporin 4 (P = 0.018). Myocardial interstitial oedema increased by 42% (95% confidence interval 31-54%) after CPB use. Patients who developed low cardiac output syndrome were in the upper half of the median percentage change of Aquaporin expression.

CONCLUSION

Time-dependent changes in cardiac Aquaporin expression may be associated with myocardial oedema and dysfunction related to CPB use.

Inhaled gold nanoparticles cause cerebral edema and upregulate endothelial aquaporin 1 expression, involving caveolin 1 dependent repression of extracellular regulated protein kinase activity

Background

Gold nanoparticles (Au-NPs) have extensive applications in electronics and biomedicine, resulting in increased exposure and prompting safety concerns for human health. After absorption, nanoparticles enter circulation and effect endothelial cells. We previously showed that exposure to Au-NPs (40–50 nm) collapsed endothelial tight junctions and increased their paracellular permeability. Inhaled nanoparticles have gained significant attention due to their biodistribution in the brain; however, little is known regarding their role in cerebral edema. The present study investigated the expression of aquaporin 1 (AQP1) in the cerebral endothelial cell line, bEnd.3, stimulated by Au-NPs.

Results

We found that treatment with Au-NPs induced AQP1 expression and increased endothelial permeability to water. Au-NP exposure rapidly boosted the phosphorylation levels of focal adhesion kinase (FAK) and AKT, increased the accumulation of caveolin 1 (Cav1), and reduced the activity of extracellular regulated protein kinases (ERK). The inhibition of AKT (GDC-0068) or FAK (PF-573228) not only rescued ERK activity but also prevented AQP1 induction, whereas Au-NP-mediated Cav1 accumulation remained unaltered. Neither these signaling molecules nor AQP1 expression responded to Au-NPs while Cav1 was silenced. Inhibition of ERK activity (U0126) remarkably enhanced Cav1 and AQP1 expression in bEnd.3 cells. These data demonstrate that Au-NP-mediated AQP1 induction is Cav1 dependent, but requires the repression on ERK activity. Mice receiving intranasally administered Au-NPs displayed cerebral edema, significantly augmented AQP1 protein levels; furthermore, mild focal lesions were observed in the cerebral parenchyma.

Conclusions

These data suggest that the subacute exposure of nanoparticles might induce cerebral edema, involving the Cav1 dependent accumulation on endothelial AQP1.

Effects of Polyethylene Glycol-20k on Postresuscitation Myocardial and Cerebral Function in a Rat Model of Cardiopulmonary Resuscitation

OBJECTIVES

Polyethylene glycol-20k is a hybrid cell impermeant that reduces ischemia injury and improves microcirculatory flow during and following low flow states through nonenergy-dependent water transfer in the microcirculation. We investigated the effects of polyethylene glycol-20k on postresuscitation microcirculation, myocardial and cerebral function, and duration of survival in a rat model of cardiopulmonary resuscitation.

DESIGN

Ventricular fibrillation was induced in 20 male Sprague Dawley rats and untreated for 6 minutes. Animals were randomized into two groups (n = 10 for each group): polyethylene glycol-20k and control. Polyethylene glycol-20k (10% solution in saline, 10% estimated blood volume) and vehicle (saline) were administered at the beginning of cardiopulmonary resuscitation by continuous IV infusion. Resuscitation was attempted after 8 minutes of cardiopulmonary resuscitation.

SETTING

University-Affiliated Research Laboratory.

SUBJECTS

Sprague Dawley Rats.

INTERVENTIONS

Polyethylene glycol-20k.

MEASUREMENTS AND MAIN RESULTS

Buccal microcirculation was measured at baseline, 1, 3, and 6 hours after return of spontaneous circulation using a side-stream dark-field imaging device. Myocardial function was measured by echocardiography at baseline and every hour postresuscitation for 6 hours. The animals were then returned to their cage and observed for an additional 72 hours. Neurologic Deficit Scores were recorded at 24, 48, and 72 hours after resuscitation. Postresuscitation ejection fraction, cardiac output, and myocardial performance index were significantly improved in animals treated with polyethylene glycol-20k (p < 0.05). Perfused buccal vessel density and microcirculatory flow index values were significantly higher at all time points in the polyethylene glycol-20k group compared with the control group. Postresuscitation cerebral function and survival rate were also significantly improved in animals that received polyethylene glycol-20k.

CONCLUSIONS

Administration of polyethylene glycol-20k following cardiopulmonary resuscitation improves postresuscitation myocardial and cerebral function, buccal microcirculation, and survival in a rat model of cardiopulmonary resuscitation.

MicroRNA-155 inhibition attenuates endoplasmic reticulum stress-induced cardiomyocyte apoptosis following myocardial infarction via reducing macrophage inflammation

Endoplasmic reticulum stress (ERS)-induced cardiomyocyte apoptosis plays an important role in the pathological process following myocardial infarction (MI). Macrophages that express microRNA-155 (miR-155) mediate cardiac inflammation, fibrosis, and hypertrophy. Therefore, we investigated if miR-155 regulates ERS-induced cardiomyocyte apoptosis after MI using a mouse model, lipopolysaccharide (LPS)-induced rat bone marrow derived macrophages (BMDMs)and hypoxia-induced neonatal rat cardiomyocytes (NRCMs). In vivo, miR-155 levelswere significantly higher in the MI group compared to the sham group. MI increasedmacrophage infiltration, nuclear factor-κB (NF-κB) activation, ERS induced-apoptosis, and SOCS1 expression, all of which were attenuated by the miR-155 antagomir, with the exception of SOCS1 expression. Additionally, post-MI cardiac dysfunction was significantly improved by miR-155 inhibition. In vitro, LPS upregulated miR-155 expression in BMDMs, and the miR-155 antagomir decreased LPS-induced macrophage inflammation and NF-κB pathway activation, but increased expression of SOCS1. Hypoxia increased NF-κB pathway activation, ERS marker expression, and apoptosis in NRCMs. Interestingly, conditioned medium from LPS-induced macrophages in combination with the miR-155 antagomir decreased, while the miR-155 agomir increased, the hypoxia-induced effects in NRCM's. The miR-155 agomir effects were reversed by inhibiting the NF-κB pathway in cardiomyocytes. Moreover, SOCS1 knockdown in LPS-induced macrophages promoted NF-κB pathway activation and ERS-induced cardiomyocyte apoptosis in the hypoxia-induced NRCMs, but the SOCS1-siRNA-induced effects were markedly decreased by miR-155 antagomir treatment. These data suggest that miR-155 inhibition attenuates ERS-induced cardiomyocyte apoptosis after MI via reducing macrophage inflammation through the SOCS1/NF-κB pathway.

Aquaporin Channels in the Heart-Physiology and Pathophysiology

Mammalian aquaporins (AQPs) are transmembrane channels expressed in a large variety of cells and tissues throughout the body. They are known as water channels, but they also facilitate the transport of small solutes, gasses, and monovalent cations. To date, 13 different AQPs, encoded by the genes AQP0–AQP12, have been identified in mammals, which regulate various important biological functions in kidney, brain, lung, digestive system, eye, and skin. Consequently, dysfunction of AQPs is involved in a wide variety of disorders. AQPs are also present in the heart, even with a specific distribution pattern in cardiomyocytes, but whether their presence is essential for proper (electro)physiological cardiac function has not intensively been studied. This review summarizes recent findings and highlights the involvement of AQPs in normal and pathological cardiac function. We conclude that AQPs are at least implicated in proper cardiac water homeostasis and energy balance as well as heart failure and arsenic cardiotoxicity. However, this review also demonstrates that many effects of cardiac AQPs, especially on excitation-contraction coupling processes, are virtually unexplored.

Inhibition of microRNA-155 attenuates sympathetic neural remodeling following myocardial infarction via reducing M1 macrophage polarization and inflammatory responses in mice

Inflammation plays an important role in sympathetic neural remodeling induced by myocardial infarction (MI). MiR-155 is a vital regulator of inflammatory responses, and macrophage-secreted miR-155 promotes cardiac fibrosis and hypertrophy. However, whether miR-155 influences MI-induced sympathetic neural remodeling is not clear. Therefore, we examined the role of miR-155 in MI-induced sympathetic neural remodeling and the related mechanisms in both an mouse model and in lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMDMs). Our data showed that miR-155 expression was significantly enhanced in the myocardial tissues of MI mice compared to sham mice. Also, MI up-regulated the electrophysiological parameters, M1 macrophage polarization, inflammatory responses, and suppressor of cytokine signaling 1 (SOCS1) expression, which coincided with the increased expression of sympathetic nerve remodeling markers(nerve growth factor, tyrosine hydroxylase and growth-associated protein 43). Except for SOCS1, these proteins were attenuated by miR-155 antagomir. In vitro, LPS-stimulation promoted miR-155 expression in BMDMs. Consistent with the in vivo findings, miR-155 antagomir diminished the LPS-induced M1 macrophage polarization, nuclear factor (NF)-κB activation, and the expression of pro-inflammatory factors and nerve growth factor; but it increased the expression of SOCS1. Inversely, miR-155 agomir significantly potentiated LPS-induced pathophysiological effects in BMDMs. MiR-155 agomir-induced effects were reversed by the NF-κB inhibitor. Mechanistically, treatment with siRNA against SOCS1 augmented the aforementioned LPS-mediated activities, which were antagonized by the addition of miR-155 antagomir. In conclusion, miR-155 inhibition downregulated NGF expression via decreasing M1 macrophage polarization and inflammatory responses dependent on the SOCS1/NF-κB pathway, subsequently diminishing MI-induced sympathetic neural remodeling and ventricular arrhythmias (VAs).

Aqp-1 Gene Knockout Attenuates Hypoxic Pulmonary Hypertension of Mice

Objective—

Hypoxic pulmonary hypertension (HPH) is characterized by proliferative vascular remodeling. Abnormal pulmonary artery smooth muscle cells proliferation and endothelial dysfunction are the primary cellular bases of vascular remodeling. AQP1 (aquaporin-1) is regulated by oxygen level and has been observed to play a role in the proliferation and migration of pulmonary artery smooth muscle cells. The role of AQP1 in HPH pathogenesis has not been directly determined to date. To determine the possible roles of AQP1 in the pathogenesis of HPH and explore its possible mechanisms.

Approach and Results—

Aqp1 knockout mice were used, and HPH model was established in this study. Primary pulmonary artery smooth muscle cells, primary mouse lung endothelial cells, and lung tissue sections from HPH model were used. Immunohistochemistry, immunofluorescence and Western blot, cell cycle, apoptosis, and migration analysis were performed in this study. AQP1 expression was upregulated by chronic hypoxia exposure, both in pulmonary artery endothelia and medial smooth muscle layer of mice. Aqp1 deficiency attenuated the elevation of right ventricular systolic pressures and mitigated pulmonary vascular structure remodeling. AQP1 deletion reduced abnormal cell proliferation in pulmonary artery and accompanied with accumulation of HIF (hypoxia-inducible factor). In vitro, Aqp1 deletion reduced hypoxia-induced proliferation, apoptosis resistance, and migration ability of primary cultured pulmonary artery smooth muscle cells and repressed HIF-1α protein stability. Furthermore, Aqp1 deficiency protected lung endothelial cells from apoptosis in response to hypoxic injury.

Conclusions—

Our data showed that Aqp1 deficiency could attenuate hypoxia-induced vascular remodeling in the development of HPH. AQP1 may be a potential target for pulmonary hypertension treatment.

Protective effect of dehydroandrographolide on obstructive cholestasis in bile duct-ligated mice

Background

Dehydroandrographolide (DA) is the main contributor to the therapeutic properties of the medicinal plant Andrographis paniculata (AP). However, it is unknown whether DA has a hepatoprotective effect on obstructive cholestasis in mice and humans.

Methods

We administered DA to mice for 5 days prior to bile duct ligation (BDL) and for the 7 days. Liver function markers, liver histology and necrosis, compensatory responses of hepatocytes, liver fibrosis and the expression of hepatic fibrogenesis markers were evaluated in BDL mice and/or human LX-2 cells.

Results

Mice treated with DA demonstrated lower levels of serum alanine transarninase (ALT), milder liver damage, liver necrosis and fibrosis formation than in vehicle control with carboxymethylcellulose (CMC) mice after BDL. DA treatment also enhanced the Mrp3 expression of hepatocytes but not Mrp4 following BDL. Further, DA treatment in BDL mice significantly reduced liver mRNA and/or protein expression of Tgf-β, Col1a1, α-Sma and Mmp2. This result was also supported by hydroxyproline analysis. The molecular mechanisms of DA treatment were also assessed in human hepatic stellate cell line (LX-2 cell). DA treatment significantly inhibited Tgf-β-induced Col1a1, Mmp2 and α-Sma expression in human LX-2 cells. These data suggested that DA treatment reduced liver damage through development of a hepatic adaptive response and inhibition of the activation of HSCs, which led to a reduction in liver fibrosis formation in BDL mice.

Conclusions

DA treatment protected against liver damage and fibrosis following BDL and might be an effective therapy for extrahepatic cholestasis due to bile duct obstruction.

Circadian networks in human embryonic stem cell-derived cardiomyocytes

Cell-autonomous circadian oscillations strongly influence tissue physiology and pathophysiology of peripheral organs including the heart, in which the circadian clock is known to determine cardiac metabolism and the outcome of for instance ischemic stress. Human pluripotent stem cells represent a powerful tool to study developmental processes in vitro, but the extent to which human embryonic stem (ES) cell-derived cardiomyocytes establish circadian rhythmicity in the absence of a systemic context is unknown. Here we demonstrate that while undifferentiated human ES cells do not possess an intrinsic functional clock, oscillatory expression of known core clock genes emerges spontaneously during directed cardiac differentiation. We identify a set of clock-controlled output genes that contain an oscillatory network of stress-related transcripts. Furthermore, we demonstrate that this network results in a time-dependent functional response to doxorubicin, a frequently used anti-cancer drug with known cardiotoxic side effects. Taken together, our data provide a framework from which the effect of oscillatory gene expression on cardiomyocyte physiology can be modeled in vitro, and demonstrate the influence of a functional clock on experimental outcome.

Abnormal expression of long non-coding RNAs in myocardial infarction

Myocardial infarction (MI) is the leading cause of fatality worldwide. Our study aimed to investigate the dysregulated long non-coding RNA (lncRNA) in MI and elucidate the mechanism of it in MI. The lncRNA and mRNA expression profiling of the whole left ventricular tissue of MI mice model (8 mice) and Sham group (8 mice) was obtained based on microarray analysis. Differentially expressed lnRNAs/mRNA (DELs/DEMs) were identified in MI. DELs/DEMs co-expression network construction, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were conducted to predict the biological functions of DEMs. Quantitative real-time polymerase chain reaction (qRT-PCR) was subjected to validate the abnormally expressed DELs in left ventricular tissues of MI mice model. Total of 168 DELs (37 up- and 131 down-regulated) and 126 DEMs (87 up- and 39 down-regulated) were identified in MI compared with Sham group. The co-expression network of candidate DELs and DEMs was constructed, which covered 219 nodes and 1775 edges. The qRT-PCR validation results indicated that ENSMUST00000124047 was significantly down-regulated in MI group and AK166279 was significantly up-regulated in MI group. ENSMUST00000121611 and NR_015515 had the up-regulated tendency in MI group compared with Sham group. The DEMs in MI were significantly enriched in 41 signaling pathways including complement and coagulation cascades, cytokine-cytokine receptor interaction and chemokine signaling pathway. The expression profiling of dysregulated DELs in MI was identified. Our results might provide useful information for exploring the pathogenesis mechanism of MI.

Clinical effects of joint application of β-sodium aescinate and mannitol in treating early swelling after upper limb trauma surgery

The aim of the present study was to examine the clinical merits of joint application of β-sodium aescinate and mannitol for the treatment of early swelling of upper limb trauma after surgery. We verified whether the expression of serum aquaporin 1 (AQP-1) was involved in swelling mechanism. A total of 102 patients with swelling after upper limb trauma surgery were enrolled into the study and divided randomly into 3 groups (n=34 cases per group). Group A was treated with β-sodium aescinate; group B was treated with with mannitol and group C was treated with both β-sodium aescinate and mannitol. The expression level of AQP-1, and clinical effects and complications before and after treatment were compared§. The time of swelling subsidence in group C was significantly shorter than that of the other two groups and differences were statistically significant (P<0.05). The recovery ratio and total efficiency in group C were significantly higher than those in other two groups and differences were statistically significant (P<0.05). Three and seven days after treatment, the AQP-1 levels in group A and group C were decreased and AQP-1 level decreased further with time. Differences of comparison within groups were statistically significant (P<0.05), although the differences of comparison between the groups showed no statistical significance (P>0.05). We also compared the AQP-1 level in group B before and after treatment, and the differences were not statistically significant (P>0.05). When the complication incidence in the 3 groups was compared, no statistical significance was detected (P>0.05). We concluded that the joint use of β-sodium aescinate and mannitol in treating early swelling after upper limb trauma surgery produced satisfactory outcomes. This might be related to reduction of the AQP-1 level.

Abrogation of CC chemokine receptor 9 ameliorates ventricular remodeling in mice after myocardial infarction

CC chemokine receptor 9 (CCR9), which is a unique receptor for CC chemokine ligand (CCL25), is mainly expressed on lymphocytes, dendritic cells (DCs) and monocytes/macrophages. CCR9 mediates the chemotaxis of inflammatory cells and participates in the pathological progression of inflammatory diseases. However, the role of CCR9 in the pathological process of myocardial infarction (MI) remains unexplored; inflammation plays a key role in this process. Here, we used CCR9 knockout mice to determine the functional significance of CCR9 in regulating post-MI cardiac remodeling and its underlying mechanism. MI was induced by surgical ligation of the left anterior descending coronary artery in CCR9 knockout mice and their CCR9+/+ littermates. Our results showed that the CCR9 expression levels were up-regulated in the hearts of the MI mice. Abrogation of CCR9 improved the post-MI survival rate and left ventricular (LV) dysfunction and decreased the infarct size. In addition, the CCR9 knockout mice exhibited attenuated inflammation, apoptosis, structural and electrical remodeling compared with the CCR9+/+ MI mice. Mechanistically, CCR9 mainly regulated the pathological response by interfering with the NF-κB and MAPK signaling pathways. In conclusion, the data reveal that CCR9 serves as a novel modulator of pathological progression following MI through NF-κB and MAPK signaling.