Corrigendum: Integrative single-cell RNA sequencing and metabolomics decipher the imbalanced lipid-metabolism in maladaptive immune responses during sepsis.

[This corrects the article DOI: 10.3389/fimmu.2023.1181697.].

4-phenylbutyric acid improves sepsis-induced cardiac dysfunction by modulating amino acid metabolism and lipid metabolism via Comt/Ptgs2/Ppara.

INTRODUCTION: Cardiac dysfunction after sepsis the most common and severe sepsis-related organ failure. The severity of cardiac damage in sepsis patients was positively associated to mortality. It is important to look for drugs targeting sepsis-induced cardiac damage. Our previous studies found that 4-phenylbutyric acid (PBA) was beneficial to septic shock by improving cardiovascular function and survival, while the specific mechanism is unclear. OBJECTIVES: We aimed to explore the specific mechanism and PBA for protecting cardiac function in sepsis. METHODS: The cecal ligation and puncture-induced septic shock models were used to observe the therapeutic effects of PBA on myocardial contractility and the serum levels of cardiac troponin-T. The mechanisms of PBA against sepsis were explored by metabolomics and network pharmacology. RESULTS: The results showed that PBA alleviated the sepsis-induced cardiac damage. The metabolomics results showed that there were 28 metabolites involving in the therapeutic effects of PBA against sepsis. According to network pharmacology, 11 hub genes were found that were involved in lipid metabolism and amino acid transport following PBA treatment. The further integrated analysis focused on 7 key targets, including Comt, Slc6a4, Maoa, Ppara, Pparg, Ptgs2 and Trpv1, as well as their core metabolites and pathways. In an in vitro assay, PBA effectively inhibited sepsis-induced reductions in Comt, Ptgs2 and Ppara after sepsis. CONCLUSIONS: PBA protects sepsis-induced cardiac injury by targeting Comt/Ptgs2/Ppara, which regulates amino acid metabolism and lipid metabolism. The study reveals the complicated mechanisms of PBA against sepsis.

Autophagy reduces aortic calcification in diabetic mice by reducing matrix vesicle body-mediated IL-1ß release.

Vascular calcification (VC) is a common pathological process of cardiovascular disease that occurs in patients with type 2 diabetes mellitus (T2DM). However, the molecular basis of VC progression remains unknown. A GEO dataset (GSE146638) was analyzed to show that microbodies and IL-1ß may play important roles in the pathophysiology of VC. The release of matrix vesicle bodies (MVBs) and IL-1ß and the colocalization of IL-1ß with MVBs or autophagosomes were studied by immunofluorescence in an in vivo diabetes mouse model with aortic calcification and an in vitro high glucose cell calcification model. MVB numbers, IL-1ß levels and autophagy were increased in calcified mouse aortas and calcified vascular smooth muscle cells (VSMCs). IL-1ß colocalized with MVBs and autophagosomes. The MVBs from calcified VSMCs induced the calcification of normal recipient VSMCs, and this effect was alleviated by silencing IL-1ß. The autophagy inducer rapamycin reduced IL-1ß expression and calcification in VSMCs, while these processes were induced by the autophagy inhibitor chloroquine. In conclusion, our results suggested that MVBs could carry IL-1ß out of cells and induce VC in normal VSMCs, and these processes could be counteracted by autophagy. These results suggested that MVB-mediated IL-1ß release may be an effective target for treating vascular calcification.

VDAC2 malonylation participates in sepsis-induced myocardial dysfunction via mitochondrial-related ferroptosis.

Sepsis-induced myocardial dysfunction (SIMD) is a prevalent and severe form of organ dysfunction with elusive underlying mechanisms and limited treatment options. In this study, the cecal ligation and puncture and lipopolysaccharide (LPS) were used to reproduce sepsis model in vitro and vivo. The level of voltage-dependent anion channel 2 (VDAC2) malonylation and myocardial malonyl-CoA were detected by mass spectrometry and LC-MS-based metabolomics. Role of VDAC2 malonylation on cardiomyocytes ferroptosis and treatment effect of mitochondrial targeting nano material TPP-AAV were observed. The results showed that VDAC2 lysine malonylation was significantly elevated after sepsis. In addition, the regulation of VDAC2 lysine 46 (K46) malonylation by K46E and K46Q mutation affected mitochondrial-related ferroptosis and myocardial injury. The molecular dynamic simulation and circular dichroism further demonstrated that VDAC2 malonylation altered the N-terminus structure of the VDAC2 channel, causing mitochondrial dysfunction, increasing mitochondrial ROS levels, and leading to ferroptosis. Malonyl-CoA was identified as the primary inducer of VDAC2 malonylation. Furthermore, the inhibition of malonyl-CoA using ND-630 or ACC2 knock-down significantly reduced the malonylation of VDAC2, decreased the occurrence of ferroptosis in cardiomyocytes, and alleviated SIMD. The study also found that the inhibition of VDAC2 malonylation by synthesizing mitochondria targeting nano material TPP-AAV could further alleviate ferroptosis and myocardial dysfunction following sepsis. In summary, our findings indicated that VDAC2 malonylation plays a crucial role in SIMD and that targeting VDAC2 malonylation could be a potential treatment strategy for SIMD.

Integrative single-cell RNA sequencing and metabolomics decipher the imbalanced lipid-metabolism in maladaptive immune responses during sepsis.

Background: To identify differentially expressed lipid metabolism-related genes (DE-LMRGs) responsible for immune dysfunction in sepsis. Methods: The lipid metabolism-related hub genes were screened using machine learning algorithms, and the immune cell infiltration of these hub genes were assessed by CIBERSORT and Single-sample GSEA. Next, the immune function of these hub genes at the single-cell level were validated by comparing multiregional immune landscapes between septic patients (SP) and healthy control (HC). Then, the support vector machine-recursive feature elimination (SVM-RFE) algorithm was conducted to compare the significantly altered metabolites critical to hub genes between SP and HC. Furthermore, the role of the key hub gene was verified in sepsis rats and LPS-induced cardiomyocytes, respectively. Results: A total of 508 DE-LMRGs were identified between SP and HC, and 5 hub genes relevant to lipid metabolism (MAPK14, EPHX2, BMX, FCER1A, and PAFAH2) were screened. Then, we found an immunosuppressive microenvironment in sepsis. The role of hub genes in immune cells was further confirmed by the single-cell RNA landscape. Moreover, significantly altered metabolites were mainly enriched in lipid metabolism-related signaling pathways and were associated with MAPK14. Finally, inhibiting MAPK14 decreased the levels of inflammatory cytokines and improved the survival and myocardial injury of sepsis. Conclusion: The lipid metabolism-related hub genes may have great potential in prognosis prediction and precise treatment for sepsis patients.

Effects of Mdivi-1 on Extending the Golden Treatment Time following Hemorrhagic Shock in Hot Environment in Rats.

It is found that a hot environment aggravates hemorrhagic shock-induced internal environment and organ dysfunction. Meanwhile mitochondria show over-fission. Whether inhibition of mitochondrial fission benefits from the early treatment of hemorrhagic shock under a hot environment is unclear. An uncontrolled hemorrhagic shock model in rats is used, and the effects of mitochondrial fission inhibitor mdivi-1 on mitochondrial function, organ function, and survival rate of rats are measured. The results show that 0.1-3 mg/kg mdivi-1 antagonizes hemorrhagic shock-induced mitochondrial fragment. In addition, mdivi-1 improves mitochondrial function, and alleviates hemorrhagic shock-induced oxidative stress and inflammation under a hot environment. Further studies show that 0.1-3 mg/kg Mdivi-1 reduces blood loss, and maintains a mean artery pressure (MAP) of 50-60 mmHg before bleeding-stops after hemorrhagic shock, compared with single Lactate Ringer's (LR) resuscitation. Notably, 1 mg/kg of Mdivi-1 extends the time of hypotensive resuscitation to 2-3 h. During 1 or 2 h of ligation, Mdivi-1 prolongs survival time and protects vital organ function by rescuing mitochondrial morphology and improving mitochondrial function. These results suggest Mdivi-1 is suitable for the early treatment of hemorrhagic shock under a hot environment and can extend the golden treatment time to 2-3 hour for hemorrhagic shock under a hot environment.

Nano Parthenolide Improves Intestinal Barrier Function of Sepsis by Inhibiting Apoptosis and ROS via 5-HTR2A.

Background: Intestinal barrier dysfunction is an important complication of sepsis, while the treatment is limited. Recently, parthenolide (PTL) has attracted much attention as a strategy of sepsis, but whether nano parthenolide (Nano PTL) is therapeutic in sepsis-induced intestinal barrier dysfunction is obscured. Methods: In this study, cecal ligation and puncture (CLP)-induced sepsis rats and lipopolysaccharide (LPS)-stimulated intestinal epithelial cells (IECs) were used to investigate the effect of PTL on intestinal barrier dysfunction. Meanwhile, we synthesized Nano PTL and compared the protective effect of Nano PTL with ordinary PTL on intestinal barrier function in septic rats and IECs. Network pharmacology and serotonin 2A (5-HTR2A) inhibitor were used to explore the mechanism of PTL on the intestinal barrier function of sepsis. Results: The encapsulation rate of Nano PTL was 95±1.5%, the drug loading rate was 11±0.5%, and the average uptake rate of intestinal epithelial cells was 94%. Ordinary PTL and Nano PTL improved the survival rate and survival time of septic rats, reduced the mean arterial pressure and the serum level of inflammatory cytokines, and protected the liver and kidney functions in vivo, and increased the value of transmembrane resistance (TEER) reduced the reactive oxygen species (ROS) and apoptosis in IECs in vitro through 5-HTR2A. Nano PTL had better effect than ordinary PTL. Conclusion: Ordinary PTL and Nano PTL can protect the intestinal barrier function of septic rats by inhibiting apoptosis and ROS through up-regulating 5-HTR2A, Nano PTL is better than ordinary PTL.

Effects of Malate Ringer's solution on myocardial injury in sepsis and enforcement effects of TPP@PAMAM-MR.

BACKGROUND: Myocardial dysfunction played a vital role in organ damage after sepsis. Fluid resuscitation was the essential treatment in which Lactate Ringer's solution (LR) was commonly used. Since LR easily led to hyperlactatemia, its resuscitation effect was limited. Malate Ringer's solution (MR) was a new resuscitation crystal liquid. Whether MR had a protective effect on myocardial injury in sepsis and the relevant mechanism need to be studied. METHODS: The cecal ligation and puncture (CLP) inducing septic model and lipopolysaccharide (LPS) stimulating cardiomyocytes were used, and the cardiac function, the morphology and function of mitochondria were observed. The protective mechanism of MR on myocardial injury was explored by proteomics. Then the effects of TPP@PAMAM-MR, which consisted of the mitochondria- targeting polymer embodied malic acid, was further observed. RESULTS: Compared with LR, MR resuscitation significantly prolonged survival time, improved the cardiac function, alleviated the damages of liver, kidney and lung following sepsis in rats. The proteomics of myocardial tissue showed that differently expressed proteins between MR and LR infusion involved oxidative phosphorylation, apoptosis. Further study found that MR decreased ROS, improved the mitochondrial morphology and function, and ultimately enhanced mitochondrial respiration and promoted ATP production. Moreover, MR infusion decreased the expression of apoptosis-related proteins and increased the expression of anti-apoptotic proteins. TPP@PAMAM@MA was a polymer formed by wrapping L-malic acid with poly amido amine (PAMAM) modified triphenylphosphine material. TPP@PAMAM-MR (TPP-MR), which was synthesized by replacing the L-malic acid of MR with TPP@PAMAM@MA, was more efficient in targeting myocardial mitochondria and was superior to MR in protecting the sepsis-inducing myocardial injury. CONCLUSION: MR was suitable for protecting myocardial injury after sepsis. The mechanism was related to MR improving the function and morphology of cardiomyocyte mitochondria and inhibiting cardiomyocyte apoptosis. The protective effect of TPP-MR was superior to MR.

Low-dose norepinephrine in combination with hypotensive resuscitation may prolong the golden window for uncontrolled hemorrhagic shock in rats.

Hypotension resuscitation is an important principle for the treatment after trauma. Current hypotensive resuscitation strategies cannot obtain an ideal outcome for remote regions. With the uncontrolled hemorrhagic shock (UHS) model in rats, the effects of norepinephrine (NE) on the tolerance time of hypotensive resuscitation, blood loss, vital organ functions, and animal survival were observed. Before bleeding was controlled, only the LR infusion could effectively maintain the MAP to 50-60 mmHg for 1 h, while the MAP gradually decreased with prolonging time, even with increasing infusion volume. Low-dose NE during hypotensive resuscitation prolonged the hypotensive tolerance time to 2-3 h, and the effect of 0.3 µg/kg/min NE was the best. Further studies showed that 0.3 µg/kg/min NE during hypotensive resuscitation significantly lightened the damage of organ function induced by UHS via protecting mitochondrial function, while the LR infusion did not. At the same time, NE administration improved Hb content, DO2, and VO2, and restored liver and kidney blood flow. The survival results showed that low-dose NE administration increased the survival rate and prolonged the survival time. Together, low-dose NE during hypotensive resuscitation was suitable for the early treatment of UHS, which can strive for the golden window of emergency treatment for serious trauma patients by reducing blood loss and protecting vital organ functions.

The Landscape of Featured Metabolism-Related Genes and Imbalanced Immune Cell Subsets in Sepsis.

Sepsis is a heterogeneous disease state triggered by an uncontrolled inflammatory host response with high mortality and morbidity in severely ill patients. Unfortunately, the treatment effectiveness varies among sepsis patients and the underlying mechanisms have yet to be elucidated. The present aim is to explore featured metabolism-related genes that may become the biomarkers in patients with sepsis. In this study, differentially expressed genes (DEGs) between sepsis and non-sepsis in whole blood samples were identified using two previously published datasets (GSE95233 and GSE54514). A total of 66 common DEGs were determined, namely, 52 upregulated and 14 downregulated DEGs. The Gene Set Enrichment Analysis (GSEA) results indicated that these DEGs participated in several metabolic processes including carbohydrate derivative, lipid, organic acid synthesis oxidation reduction, and small-molecule biosynthesis in patients with sepsis. Subsequently, a total of 8 hub genes were screened in the module with the highest score from the Cytoscape plugin cytoHubba. Further study showed that these hub DEGs may be robust markers for sepsis with high area under receiver operating characteristic curve (AUROC). The diagnostic values of these hub genes were further validated in myocardial tissues of septic rats and normal controls by untargeted metabolomics analysis using liquid chromatography-mass spectrometry (LC-MS). Immune cell infiltration analysis revealed that different infiltration patterns were mainly characterized by B cells, T cells, NK cells, monocytes, macrophages, dendritics, eosinophils, and neutrophils between sepsis patients and normal controls. This study indicates that metabolic hub genes may be hopeful biomarkers for prognosis prediction and precise treatment in sepsis patients.

Protective Effect of Moderate Hypotonic Fluid on Organ Dysfunction via Alleviating Lethal Triad Following Seawater Immersion With Hemorrhagic Shock in Rats.

Previous studies found that seawater immersion combined with hemorrhagic shock (SIHS) induced serious organ function disorder, and lethal triad was a critical sign. There were no effective treatments of SIHS. Fluid resuscitation was the initial measurement for early aid following hemorrhagic shock, while the proper fluid for SIHS is not clear. Effects of different osmotic pressures [lactated Ringer's (LR) solution, 0.3% saline, 0.6% saline, and 0.9% normal saline] on the lethal triad, mitochondrial function, vital organ functions, and survival were observed following SIHS in rats. The results showed that SIHS led to an obvious lethal triad, which presented the decrease of the body temperature, acidosis, and coagulation functions disorder in rats. Fluid resuscitation with different osmotic pressures recovered the body temperature and corrected acidosis with different levels; effects of 0.6% normal saline were the best; especially for the coagulation function, 0.6% normal saline alleviated the lethal triad significantly. Further studies showed that SIHS resulted in the damage of the mitochondrial function of vital organs, the increase of the vascular permeability, and, at the same time, the organ function including cardiac, liver, and kidney was disordered. Conventional fluid such as LR or 0.9% normal saline could not improve the mitochondrial function and vascular leakage and alleviate the damage of the organ function. While moderate hypotonic fluid, the 0.6% normal saline, could lighten organ function damage via protecting mitochondrial function. The 0.6% normal saline increased the left ventricular fractional shortening and the left ventricular ejection fraction, and decreased the levels of aspartate transaminase, alanine transferase, blood urea nitrogen, and creatinine in the blood. The effects of fluids with different osmotic pressures on the mean arterial pressure (MAP) had a similar trend as above parameters. The survival results showed that the 0.6% normal saline group improved the survival rate and prolonged the survival time, the 72 h survival rate was 7/16, as compared with the LR group (3/16). The results indicate that appropriate hypotonic fluid is suitable after SIHS, which alleviates the lethal triad, protects the mitochondrial function and organ functions, and prolongs the survival time.

Protective Effects of Dexmedetomidine on Sepsis-Induced Vascular Leakage by Alleviating Ferroptosis via Regulating Metabolic Reprogramming.

INTRODUCTION: Vascular leakage plays a vital role in sepsis-induced multi-organ dysfunction. Currently, no specific measures are available for vascular leakage. Ferroptosis, as a recently recognized form of cell death, plays a crucial role in cell dysfunction. It is still unknown whether ferroptosis participates in the occurrence of organ dysfunction following sepsis. Our previous study showed that dexmedetomidine (Dex) could alleviate sepsis-induced organ dysfunction. However, whether the mechanism is related to ferroptosis is not clear. METHODS: The publicly available datasets of septic patients were reanalyzed, and septic models in vivo and vitro by cecal ligation and puncture and lipopolysaccharide-stimulated vascular endothelial cells (VECs) were applied. The occurrence of ferroptosis in septic patients and rats was observed, and the protective effects of Dex on ferroptosis, and related mechanisms on regulating metabolic reprogramming and mitochondrial fission were further studied. RESULTS: The transcriptomics data of patients from the GEO database showed that ferroptosis was closely related to sepsis. Sepsis induced significant ferroptosis in VECs by metabolomics analysis. The level of lipid peroxidation was increased in VECs, and the mitochondrial cristae was decreased after sepsis. Metabolomics analysis showed that Dex activated the pentose phosphate pathway and increased glutathione in VECs via up-regulation of G6PD expression. Dex could antagonize sepsis-induced the decrease in the level of Nrf2. The Nrf2 inhibitor reversed the protective effect of Dex on ferroptosis. Further study showed that Dex significantly alleviated sepsis-induced mitochondrial over-division, improved mitochondrial function, and decreased ROS, further inhibiting the ferroptosis of VECs. Dex alleviated the permeability of vessels by reducing ferroptosis and enhanced the intercellular junction of VECs. CONCLUSION: Dex protects vascular leakage following sepsis by inhibiting ferroptosis. The mechanism is mainly related to metabolic reprogramming via Nrf2 up-regulation and inhibition of mitochondrial fission.

Mitochondrial Drp1 recognizes and induces excessive mPTP opening after hypoxia through BAX-PiC and LRRK2-HK2.

Mitochondrial mass imbalance is one of the key causes of cardiovascular dysfunction after hypoxia. The activation of dynamin-related protein 1 (Drp1), as well as its mitochondrial translocation, play important roles in the changes of both mitochondrial morphology and mitochondrial functions after hypoxia. However, in addition to mediating mitochondrial fission, whether Drp1 has other regulatory roles in mitochondrial homeostasis after mitochondrial translocation is unknown. In this study, we performed a series of interaction and colocalization assays and found that, after mitochondrial translocation, Drp1 may promote the excessive opening of the mitochondrial permeability transition pore (mPTP) after hypoxia. Firstly, mitochondrial Drp1 maximumly recognizes mPTP channels by binding Bcl-2-associated X protein (BAX) and a phosphate carrier protein (PiC) in the mPTP. Then, leucine-rich repeat serine/threonine-protein kinase 2 (LRRK2) is recruited, whose kinase activity is inhibited by direct binding with mitochondrial Drp1 after hypoxia. Subsequently, the mPTP-related protein hexokinase 2 (HK2) is inactivated at Thr-473 and dissociates from the mitochondrial membrane, ultimately causing structural disruption and overopening of mPTP, which aggravates mitochondrial and cellular dysfunction after hypoxia. Thus, our study interprets the dual direct regulation of mitochondrial Drp1 on mitochondrial morphology and functions after hypoxia and proposes a new mitochondrial fission-independent mechanism for the role of Drp1 after its translocation in hypoxic injury.

Protective Effects of Inhibition of Mitochondrial Fission on Organ Function After Sepsis.

Sepsis-associated organ dysfunction plays a critical role in its high mortality, mainly in connection with mitochondrial dysfunction. Whether the inhibition of mitochondrial fission is beneficial to sepsis-related organ dysfunction and underlying mechanisms are unknown. Cecal ligation and puncture induced sepsis in rats and dynamic related protein 1 knockout mice, lipopolysaccharide-treated vascular smooth muscle cells and cardiomyocytes, were used to explore the effects of inhibition of mitochondrial fission and specific mechanisms. Our study showed that mitochondrial fission inhibitor Mdivi-1 could antagonize sepsis-induced organ dysfunction including heart, vascular smooth muscle, liver, kidney, and intestinal functions, and prolonged animal survival. The further study showed that mitochondrial functions such as mitochondrial membrane potential, adenosine-triphosphate contents, reactive oxygen species, superoxide dismutase and malonaldehyde were recovered after Mdivi-1 administration via improving mitochondrial morphology. And sepsis-induced inflammation and apoptosis in heart and vascular smooth muscle were alleviated through inhibition of mitochondrial fission and mitochondrial function improvement. The parameter trends in lipopolysaccharide-stimulated cardiomyocytes and vascular smooth muscle cells were similar in vivo. Dynamic related protein 1 knockout preserved sepsis-induced organ dysfunction, and the animal survival was prolonged. Taken together, this finding provides a novel effective candidate therapy for severe sepsis/septic shock and other critical clinical diseases.

Mechanism of α1-Adrenergic Receptor-Induced Increased Contraction of Rat Mesenteric Artery in Aging Hypertension Rats.

INTRODUCTION: Vasoconstriction is triggered by an increase in intracellular-free calcium concentration. Growing evidence indicates that contraction is also regulated by calcium-independent mechanisms involving RhoA-Rho kinase (ROCK), protein kinase C (PKC), and so on. In this study, we studied the changes of vascular reactivity as well as the underlying signaling pathways in aging spontaneously hypertensive rats (SHRs). METHODS: The artery tension induced by α1-adrenergic receptor activator (α1-AR) phenylephrine (PE) was measured in the absence or presence of myosin light chain kinase (MLCK), PKC, and ROCK inhibitors. The α1-AR, PKC, ROCK, phosphorylation of myosin light chain (MLC), and PKC-potentiated phosphatase inhibitors of 17 kDa (CPI-17) of rat mesenteric arteries were analyzed at the mRNA level or protein level. RESULTS: The vascular tension measurements showed that there was a significant increase in the mesenteric artery contraction induced by PE in old SHR. MLCK inhibitor ML-7 can similarly inhibit PE-induced vasoconstriction. PKC inhibitor GF109203X has the weakest inhibitory effect on PE-induced contraction in old SHR. At the presence of ROCK inhibitor H1152, PE-induced contraction was significantly reduced in young Wistar-Kyoto (WKY) rats, but this phenomenon disappeared in other rats. Furthermore, in old SHR the protein expression of α1-AR decreased and phosphorylation of MLC and CPI-17 were upregulated and MLC phosphatase (MLCP) activity was significantly lower. The expressions of PKC were upregulated in SHR and old rats. In addition, the expression of ROCK-1 was decreased and ROCK-2 was significantly upregulated with age in SHR. CONCLUSION: In aging hypertension, the expression/activity of PKC or ROCK-2/CPI-17 excessively increased, MLCP activity decreased and MLC phosphorylation enhanced, leading to increased α1-AR-induced vasoconstriction.

Hydroxysafflor yellow A actives BKCa channels and inhibits L-type Ca channels to induce vascular relaxation.

Hydroxy-safflor yellow A (HSYA) can exert a variety of effects upon the vascular system. However, the underlying mechanisms are not clear. The present study is to investigate its vasodilating effect and the mechanisms. Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) were enrolled for studying effects of HSYA on blood pressure, vasodilation, intracellular Ca2+ transient and membrane ion channels. Vasodilation and intracellular Ca2+ transient were measured by using vasomotor assay and fluorescence imaging system, respectively. The effect of HSYA on the large conductance Ca2+ activated and voltage-gated potassium channel (BKCa channel) currents in rat mesentery artery and on L-type calcium channel (Ca-L) currents in HEK293cells expressed with Ca-L were investigated using patch clamp techniques. Blood pressure of SHR and WKY rats were concentration dependently reduced by HSYA with a larger effect of HSYA in SHR than that in WKY rats. The tension of mesenteric arteries induced by 3 µM phenylephrine was attenuated by HSYA (IC50 = 90.8 µΜ). Patch clamp study showed that HSYA could activate BKCa channels and suppress Ca-L channels in a concentration dependent manner. The results of calcium signaling assays indicated that HSYA could reduce the intracellular free Ca2+ level. These findings demonstrate that HSYA could activate BKCa channels and inhibit Ca-L channels and reduce intracellular free Ca2+ level, which are probably important for its vasodilatory effect.

Decreased vasodilatory effect of Tanshinone â ¡A Sodium Sulfonate on mesenteric artery in hypertension.

Tanshinone ⅡA Sodium Sulfonate (DS-201), a derivative of traditional Chinese medicinal herb Danshen, has been clinically used for various cardiovascular diseases. Previous studies showed that DS-201 induced vascular relaxation partly due to the activation of the large conductance Ca2+-activated potassium (BKCa) channels. However, the efficacy of DS-201 on the resistant vessels in hypertension remains unknown. Mesentery arteries obtained from spontaneously hypertensive rats (SHR) and hypertension patients were used in this study. The endothelium-denuded mesenteric arteries were prepared to measure the artery tension and evaluate the vasodilatory effect of DS-201. The results showed that DS-201 had a vasodilatory effect on the mesenteric artery rings pre-contracted with either phenylephrine (PE) or thromboxane mimetic U46619 in a concentration-dependent manner. However, the vasodilatory effect of DS-201 significantly decreased in hypertension than in control arteries due to a decrease in protein level of BKCa ß1subunit. A BKCa channel blocker IbTX (200 nM) significantly inhibited the relaxant effect of DS-201 on non-hypertensive arteries, whereas the BKCa channel specific agonist NS1619 rescued the vasodilating effects of DS-201 on hypertensive vessels. These results indicate that the vasodilating effect of DS-201 is BKCa-dependent. This study demonstrated that DS-201 alone may not be effective for treating hypertension, but it may be considered as therapy combined with BKCa-agonists or methods rescuing BKCa functions.