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Abstract Magnesium lithospermate B (MLB) shows multiple biological activities including anti-oxidation and anti-proliferation in various diseases. However, the function of MLB in pulmonary arterial hypertension (PAH) is still unknown. This study aims to investigate the effect of MLB on hypoxia-induced phenotypic transformation of pulmonary arterial smooth muscle cells (PASMCs) and the underlying mechanisms. SD rats (or PASMCs) were exposed to 10% O 2 for 3 weeks (or 3% O 2 for 48 h) along with MLB or NADPH oxidase （NOX） inhibitor intervention. The effects of MLB on hemodynamics, pulmonary vascular remodeling and phenotypic transformation of PASMCs were observed first. Then, its effects on the protein levels of NOX (NOX2 and NOX4), ERK and p-ERK were examined. The results showed that MLB prevented the elevation in right ventricular systolic pressure and the increase in ratio of wall thickness to vessel external diameter of pulmonary arteries in PAH rats, and attenuated phenotypic transformation of PASMCs (decrease in α-smooth muscle actin while increase in osteopontin), accompanied by downregulation of NOX (NOX2 and NOX4) protein levels, decrease of ROS and H 2 O 2 production, and suppression of the phosphorylation of ERK. NOX inhibitor (VAS2870) achieved similar results to that of MLB did in the hypoxia-treated PASMCs. Based on the observations, we conclude that MLB is able to prevent phenotypic transformation of pulmonary arteries in hypoxic PAH rats through suppression of NOX/ROS/ERK pathway, and MLB might have the potentials in PAH therapy. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Recent studies uncovered that glutamate accumulation following cerebral ischemia–reperfusion (I/R) was related to the dysfunction of miR-107/glutamate transporter-1(GLT-1) pathway and magnesium lithospermate B (MLB) possesses the pharmacological activity of anti-excitotoxicity. This study aims to explore whether MLB is able to protect rat brain from excitatory neurotoxicity during I/R by modulating miR-107/GLT-1 pathway. Rats were subjected to 2 h of cerebral ischemia following by 24 h of reperfusion to establish an I/R injury model, which showed an increase in neurological deficit score, infarct volume and cellular apoptosis concomitant with glutamate accumulation, miR-107 elevation and GLT-1 down-regulation. Administration of MLB reduced I/R-induced cerebral injury accompanied by a reverse in glutamate accumulation, miR-107 and GLT-1 expression. Next, we examined the association of MLB with miR-107/GLT-1 pathway in a nerve cell hypoxia/reoxygenation (H/R) injury model. H/R treatment increased the nerve cells apoptosis concomitant with glutamate accumulation and miR-107 elevation, and suppressed GLT-1 expression, mimicking our in vivo findings. All these effects were reversed in the presence of MLB, confirming a strong correlation between MLB and miR-107/GLT-1 pathway. Based on these observations, we conclude that MLB is able to protect the rat brain from excitatory neurotoxicity during I/R through the regulation of miR-107/GLT-1 pathway. [ABSTRACT FROM AUTHOR]

Abstract: Previous studies have demonstrated that capsaicin-sensitive sensory nerves are involved in the protection of gastric mucosa against damage by various stimuli and calcitoin gene-related peptide (CGRP) is a potential mediator in this process. This study was performed to explore the effect of vanillyl nonanoate, a capsaicin analog, on ethanol-induced gastric mucosal injury and the possible underlying mechanisms. A rat model of gastric mucosal injury was induced by oral administration of acidified ethanol and gastric tissues were collected for analysis of gastric ulcer index, cellular apoptosis, the activities of caspase-3, catalase and superoxide dismutase (SOD), levels of CGRP, TNF-α and malondialdehyde (MDA). The results showed that acute administration of ethanol significantly increased gastric ulcer index concomitantly with increased cellular apoptosis, caspase-3 activity, TNF-α and MDA levels as well as decreased activities of catalase and SOD. Pretreatment with 1mg/kg vanillyl nonanoate significantly attenuated ethanol-induced gastric mucosal injury and cellular apoptosis accompanied by increase of CGRP expression, and SOD activity and decrease of caspase-3 activity, TNF-α and MDA levels. The effects of vanillyl nonanoate were inhibited by capsazepine, an antagonist of capsaicin receptor. Our results suggested that vanillyl nonanoate was able to protect the gastric mucosa against ethanol-induced gastric mucosal injury. The underlying mechanism is related to stimulation of CGRP release and subsequent suppression of ethanol-induced inflammatory reaction, cellular apoptosis and oxidative stress. [Copyright &y& Elsevier]

Nuclear myosin regulates gene transcription and this novel function might be modulated through phosphorylation of the myosin regulatory light chain (p-MLC 20 ). Nonmuscle MLC 20 (nmMLC 20 ) is also present in the nuclei of cardiomyocytes and a potential nmMLC 20 binding sequence has been identified in the promoter of the xanthine oxidase (XO) gene. Thus, we investigated its function in the regulation of XO transcription after myocardial ischemia/reperfusion (IR). In a rat model of myocardial IR and a cardiomyocyte model of hypoxia/reoxygenation (HR) injury, the cardiac or cell injury, myosin light chain kinase (MLCK) content, XO expression and activity, XO-derived products, and level of nuclear p-nmMLC 20 were detected. Coimmunoprecipitation (co-IP), chromatin immunoprecipitation, DNA pull-down, and luciferase reporter gene assays were used to decipher the molecular mechanisms through which nmMLC 20 promotes XO expression. IR or HR treatment dramatically elevated nuclear p-nmMLC 20 level, accompanied by increased XO expression, activity, and products (H 2 O 2 and uric acid), as well as the IR or HR injury; these effects were ameliorated by inhibition of MLCK or knockdown of nmMLC 20 . Our findings from these experiments demonstrated that nuclear p-nmMLC 20 binds to the consensus sequence GTCGCC in the XO gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and hence activates XO gene transcription. These results suggest that nuclear p-nmMLC 20 plays an important role in IR/HR injury by transcriptionally upregulating XO gene expression to increase oxidative stress in myocardium. Our findings demonstrate nuclear nmMLC 20 as a potential new therapeutic target to combat cardiac IR injury. [ABSTRACT FROM AUTHOR]

[Display omitted] Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) is a multifunctional protein. MALT1 functions as an adaptor protein to assemble and recruit proteins such as B-cell lymphoma 10 (BCL10) and caspase-recruitment domain (CARD)-containing coiled-coil protein 11 (CARD11). Conversely it also acts as a paracaspase to cleave specified substrates. Because of its involvement in immunity, inflammation and cancer through its dual functions of scaffolding and catalytic activity, MALT1 is becoming a promising therapeutic target in B cell- and T cell-related diseases. There is growing evidence that the function of MALT1 is subtly modulated via post-translational modifications. This review summarized recent progress in relevant studies regarding the physiological and pathophysiological functions of MALT1, post-translational modifications of MALT1 and its role in B cell- and T cell- related diseases. In addition, the current available MALT1 inhibitors were also discussed. [ABSTRACT FROM AUTHOR]

Iron overload triggers the ferroptosis in the heart following ischemia/reperfusion (I/R) and transferrin receptor 1 (TfR1) charges the cellular iron uptake. Bioinformatics analysis shows that the three molecules of ubiquitin-specific protease 7 (USP7), p53 and TfR1 form a unique pathway of USP7/p53/TfR1. This study aims to explore whether USP7/p53/TfR1 pathway promotes ferroptosis in rat hearts suffered I/R and the underlying mechanisms. The SD rat hearts were subjected to 1 h-ischemia plus 3 h-reperfusion, showing myocardial injury (increase in creatine kinase release, infarct size, myocardial fiber loss and disarray) and up-regulation of USP7, p53 and TfR1 concomitant with an increase of ferroptosis (reflecting by accumulation of iron and lipid peroxidation while decrease of glutathione peroxidase activity). Inhibition of USP7 activated p53 via suppressing deubiquitination, which led to down-regulation of TfR1, accompanied by the decreased ferroptosis and myocardial I/R injury. Next, H9c2 cells underwent hypoxia/reoxygenation (H/R) in vitro to mimic the myocardial I/R model in vivo. Consistent with the results in vivo, inhibition or knockdown of USP7 reduced the H/R injury (decrease of LDH release and necrosis) and enhanced the ubiquitination of p53 along with the decreased levels of p53 and TfR1 as well as the attenuated ferroptosis (manifesting as the decreased iron content and lipid peroxidation while the increased GPX activity). Knockdown of TfR1 inhibited H/R-induced ferroptosis without p53 deubiquitination. Based on these observations, we conclude that a novel pathway of USP7/p53/TfR1 has been identified in the I/R-treated rat hearts, where up-regulation of USP7promotes ferrptosis via activation of the p53/TfR1 pathway. Image 1 • The protein levels of USP7, p53 and TfR1 are all elevated in the I/R-treated rat hearts. • Suppression of USP7 mitigate the myocardial I/R injury via reduction of ferroptosis. • USP7 promotes ferroptosis in the I/R-treated hearts via activation of p53/TfR1 pathway. [ABSTRACT FROM AUTHOR]

Abstract Methyl protodioscin (MPD) is reported to relieve angina pectoris and myocardial ischemia, and mitochondrial E3 ubiquitin ligase 1 (Mul1) plays a key role in maintaining mitochondrial functions. Bioinformatic analysis shows potential interactions between MPD and Mul1. This study aims to explore whether MPD could protect rat brain against ischemia/reperfusion (I/R) injury through regulation of Mul1/ superoxide dismutase 2 (SOD2) pathway. The SD rat brains were subjected to 2 h of ischemia following by 24 h of reperfusion, which showed I/R injury (increase in neurological deficit score and infarct volume), up-regulation of Mul1 and down regulation of SOD2, these phenomena were attenuated by MPD treatment (3 or 10 mg/kg, i.g.). Consistently, in cultured HT22 cells, hypoxia-reoxygenation (H/R) treatment induced cellular injury (apoptosis and LDH release) concomitant with up-regulation of Mul1 and down regulation of SOD2, these phenomena were blocked in the presence of MPD (5 μM). Knockdown of Mul1 could also decrease SOD2 protein levels in HT22 cells accompanied by alleviation of H/R injury (reduction of apoptosis and LDH release). In agreement with the change of SOD2, reactive oxygen species generation was increased in H/R-treated HT22 cells while decreased in the presence of MPD. Based on these observations, we conclude that upregulation of Mul1 in rat brain contributes to cerebral I/R injury via suppression of SOD2 and that MPD protects rat brain from I/R injury through a mechanism involving regulation of Mul1/SOD2 pathway. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

The dysregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and/or solute carrier family 7 member 11 (SLC7A11) is believed to contribute to ferroptosis in the hearts suffered ischemia/reperfusion (I/R), but the mechanisms behind the dysregulation of them are not fully elucidated. Mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) can function as a paracaspase to cleave specified substrates and it is predicted to interact with Nrf2. This study aims to explore whether targeting MALT1 can reduce I/R-induced ferroptosis via enhancing the Nrf2/SLC7A11 pathway. The SD rat hearts were subjected to 1h-ischemia plus 3h-reperfusion to establish the I/R injury model, which showed myocardial injuries (increase in infarct size and creatine kinase release) and up-regulation of MALT1 while downregulation of Nrf2 and SLC7A11 concomitant with the increased ferroptosis, reflecting by an increase in glutathione peroxidase 4 (GPX4) level while decreases in the levels of acyl-CoA synthetase long chain family member 4 (ACSL4), total iron, Fe2+ and lipid peroxidation (LPO); these phenomena were reversed in the presence of MI-2, a specific inhibitor of MALT1. Consistently, similar results were achieved in the cultured cardiomyocytes subjected to 8h-hypoxia plus 12h-reoxygenation. Furthermore, micafungin, an antifungal drug, could also exert beneficial effect on mitigating myocardial I/R injury via inhibition of MALT1. Based on these observations, we conclud that inhibition of MALT1 can reduce I/R-induced myocardial ferroptosis through enhancing the Nrf2/SLC7A11 pathway; and MALT1 may be used as a potential target to seek novel or existing drugs (such as micafungin) for treating myocardial infarction. [Display omitted] • Upregulation of MALT1 occurs in rat hearts suffered ischemia/reperfusion. • Inhibition of MALT1 reduces I/R-induced ferroptosis via enhancing the Nrf2/SLC7A11 pathway. • Micafungin mitigate myocardial I/R injury via inhibition of MALT1. [ABSTRACT FROM AUTHOR]

Fasudil is a potent Rho-kinase (ROCK) inhibitor and can relax smooth muscle or cardiac muscle contraction through decreasing the phosphorylation level of myosin regulatory light chain (p-MLC 20 or p-MLC2v), while p-MLC2v can function as a transcription factor to promote the NADPH oxidase 2 (NOX2) expression in rat hearts subjected to ischemia/reperfusion (I/R). This study aims to explore whether fasudil can protect the rat hearts against I/R oxidative injury through suppressing NOX2 expression via reduction of p-MLC2v level. The SD rat hearts were subjected to 1 h-ischemia plus 3 h-reperfusion, which showed myocardial injuries (myocardial fiber loss and disarray, increase of creatine kinase release and myocardial infarction/apoptosis), increase in ROCK activity and nuclear p-MLC 2v level concomitant with up-regulation of NOX2 and H 2 O 2 production; these phenomena were attenuated by fasudil in a dose-dependent manner. Next, we verified the cardioprotective effect of fasudil and the underlying mechanisms in hypoxia-reoxygenation (H/R) -treated H9c2 cells. Consistent with the results in vivo, the H/R-treated H9c2 cells showed cellular injury (increase in apoptotic ratio), elevation in ROCK activity and nuclear p-MLC 2v level, accompanied by up-regulation of NOX2 and H 2 O 2 production; these effects were blocked in the presence of fasudil in a dose-dependent way. Based on these observations, we conclude that beneficial effect of fasudil against myocardial I/R or H/R oxidative injury is related to the suppression of NOX2 expression through decrease of the p-MLC2v level. Our findings also highlight that intervention of MLC2v phosphorylation by drugs may provide a novel strategy to protect heart from I/R oxidative injury. [ABSTRACT FROM AUTHOR]

Numerous studies demonstrate that reactive aldehydes are highly toxic and aldehyde dehydrogenase 2 (ALDH2)-mediated detoxification of reactive aldehydes is thought as an endogenous protective mechanism against reactive aldehydes-induced cell injury. This study aims to explore whether lipoic acid, a potential ALDH2 activator, is able to protect gastric mucosa from ethanol-induced injury through a mechanism involving clearance of reactive aldehydes. The rats received 60% of acidified ethanol through intragastric administration and held for 1 h to establish a mucosal injury model. Lipoic acid (10 or 30 mg/kg) or Alda-1 (a positive control, 10 mg/kg) was given 45 min before the ethanol treatment. The gastric tissues were collected for analysis of gastric ulcer index, cellular apoptosis, 4-hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) contents, and ALDH2 activity. The results showed that acute administration of ethanol led to an increase in gastric ulcer index, cellular apoptosis, 4-HNE and MDA contents concomitant with a decrease in ALDH2 activity; these phenomena were reversed by lipoic acid or Alda-1. The gastric protection of lipoic acid was attenuated in the presence of ALDH2 inhibitor. Based on these observations, we conclude that lipoic acid exerts the beneficial effects on ethanol-induced injury through a mechanism involving, at least in part, ALDH2 activation. As a dietary supplement or a medicine already in some countries, lipoic acid can be used to treat the ethanol - induced gastric mucosal injury. [ABSTRACT FROM AUTHOR]

Vascular peroxidase 1 (VPO1) plays an important role in mediation of vascular remodeling with pulmonary arterial hypertension (PAH). This study aims to determine whether VPO1 can promote phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) and the underlying mechanisms. Sprague-Dawley (SD) rats were exposed to 10 % O 2 for 21 days to establish the model of vascular remodeling in pulmonary arterial hypertension. PASMCs were incubated with 3 % O 2 for 48 h to induce phenotypic transformation. Western blot was performed to detect the expressions of target proteins. The 5-ethynyl-2′-deoxyuridine (EdU) assay was conducted to measure the proliferation of PASMCs. In the rats exposed to hypoxia, there were increases in right ventricular systolic pressure, pulmonary vascular remodeling and phenotypic transformation of PASMCs (the down-regulated contractile proteins of α-smooth muscle actin, smooth muscle 22α while the up-regulated synthetic proteins of osteopontin, cyclinD1), accompanied by up-regulation of VPO1, increase of hypochlorous acid (HOCl) production and elevation of the phosphorylation of ERK. In the cultured PASMCs exposed to hypoxia, similar results were achieved but they were reversed by VPO1 small interfering RNA (VPO1 siRNA) or HOCl inhibitor. Replacement of hypoxia with NaOCl could induce PASMCs phenotypic transformation and activate the ERK signaling. Furthermore, ERK inhibitor (PD98059) could also attenuate hypoxia-induced PASMCs phenotypic transformation. VPO1 play a pivotal role in promotion of phenotypic transformation of PASMCs under hypoxic condition through activation of VPO1/HOCl/ERK pathway. It might serve as a potential target for prevention of pulmonary vascular remodeling. [Display omitted] [ABSTRACT FROM AUTHOR]

Mitochondrial E3 ubiquitin ligase 1 (Mul1) is a multifunctional mitochondrial membrane protein with its RING domain exposed to the cytoplasm. On the one hand, Mul1 functions as a ubiquitin-ligase to ubiquitinate a bunch of signal molecules, such as mitofusin2 (Mfn2), Akt, p53 and ULK1, through its RING finger domain, leading to proteins degradation. On the other hand, Mul1 acts as a small ubiquitin-like modifiers (SUMO) E3 ligase to sumoylate certain proteins, such as dynamin-related protein 1 (Drp1), enhancing protein stabilization. Through the dual functions of ubiquitination and SUMOylation, Mul1 involves in regulation of many physiological and pathological processes, such as mitochondrial dynamics, cell growth, apoptosis and mitophagy. In addition, Mul1 can also directly activate or interact with some proteins, such as NF-κB and JNK, to take part in the regulation of cellular apoptosis. This review summarizes recent progress in relevant studies on the physiological and pathological functions of Mul1 and pays special attention to its role in regulation of mitochondrial dynamics. [ABSTRACT FROM AUTHOR]

Non-muscle myosin regulatory light chain (nmMLC 20 ) is reported to exert transcriptional function in regulation of gene expression, and NADPH oxidase (NOX)-derived reactive oxygen species contribute to vascular remodeling of pulmonary artery hypertension (PAH). This study aims to determine if nmMLC 20 can promote endothelial progenitor cells (EPCs) senescence and dysfunction through up-regulation of NOX in PAH rats. The rats were exposed to10% hypoxia for 3 weeks to establish a PAH model, which showed an increase in right ventricle systolic pressure, right ventricular and pulmonary vascular remodeling, and the accelerated senescence and impaired functions in EPCs, accompanied by an increase in Rho-kinase (ROCK) and NOX activities, p-nmMLC 20 level, NOX expression and H 2 O 2 content; these phenomena were reversed by fasudil, a selective inhibitor of ROCK. Next, normal EPCs were cultured under hypoxia to induce senescence in vitro. Consistent with the in vivo findings, hypoxia increased the senescence and dysfunction of EPCs concomitant with an increase in ROCK and NOX activities, p-nmMLC 20 level, NOX expression and H 2 O 2 content; these phenomena were reversed by fasudil. Knockdown of nmMLC 20 showed similar results to that of fasudil except no effect on ROCK activity. Based on these observations, we conclude that nmMLC 20 could promote the senescence and dysfunctions of EPCs in PAH through up-regulation of NOX in a phosphorylation-dependent manner. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies demonstrate that alpha lipoic acid can prevent nitroglycerin tolerance by restoring aldehyde dehydrogenase 2 (ALDH2) activity and ALDH2-mediated detoxification of aldehydes is thought as an endogenous mechanism against ischemia–reperfusion injury. This study was performed to explore whether the cardioprotective effect of alpha lipoic acid was related to activation of ALDH2 and the underlying mechanisms. In a Langendorff model of ischemia–reperfusion in rats, cardiac function, activities of creatine kinase (CK) and ALDH2, contents of 4-hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) were measured. In a cell model of hypoxia–reoxygenation, the apoptosis, ALDH activity, reactive oxygen species level, 4-HNE and MDA contents were examined. In the isolated hearts, ischemia–reperfusion treatment led to cardiac dysfunction accompanied by an increase in 4-HNE and MDA contents. Pretreatment with lipoic acid significantly up-regulated myocardial ALDH2 activity concomitantly with an improvement of cardiac dysfunction and a decrease in 4-HNE and MDA contents, these effects were blocked by the inhibitor of ALDH2. Similarly, in the cultured cardiomyocytes, hypoxia–reoxygenation treatment induced apoptosis accompanied by an increase in the production of reactive oxygen species, 4-HNE and MDA. Administration of lipoic acid significantly up-regulated cellular ALDH2 activity concomitantly with a reduction in apoptosis, production of reactive oxygen species, 4-HNE and MDA, these effects were reversed in the presence of ALDH2 or PKCε inhibitors. Our results suggest that the cardioprotective effects of lipoic acid on ischemia–reperfusion injury are through a mechanism involving ALDH2 activation. The regulatory effect of lipoic acid on ALDH2 activity is dependent on PKCε signaling pathway. [Copyright &y& Elsevier]

Allopurinol, a xanthine oxidase (XO) inhibitor, is reported to alleviate myocardial ischemia/reperfusion (I/R) injury by reducing the production of reactive oxygen species (ROS). As an XO-derived product, H 2 O 2 can act as a substrate of vascular peroxidase 1 (VPO1) to induce the generation of hypochlorous acid (HOCl), a potent oxidant. This study aims to explore whether the XO/VPO1 pathway is involved in the anti-oxidative effects of allopurinol on the myocardial I/R injury. In a rat heart model of I/R, allopurinol alleviated I/R oxidative injury accompanied by decreased XO activity, XO-derived products (H 2 O 2 and uric acid), and VPO1 expression (mRNA and protein). In a cardiac cell model of hypoxia/reoxygenation (H/R), allopurinol or XO siRNA reduced H/R injury concomitant with decreased XO activity, VPO1 expression as well as the XO and VPO1-derived products (H 2 O 2 , uric acid, and HOCl). Although knockdown of VPO1 could also exert a beneficial effect on H/R injury, it did not affect XO activity, XO expression, and XO-derived products. Based on these observations, we conclude that the novel pathway of XO/VPO1 is responsible for, at least partly, myocardial I/R-induced oxidative injury, and allopurinol exerted the cardioprotective effects on myocardial I/R injury via inhibiting the XO/VPO1 pathway. [Display omitted] [ABSTRACT FROM AUTHOR]

Necroptosis, ferroptosis and cyclophilin D (Cyp D)-dependent necrosis contribute to myocardial ischemia/reperfusion (I/R) injury, and ponatinib, deferoxamine and cyclosporine are reported to inhibit necroptosis, ferroptosis and Cyp D-dependent necrosis, respectively. This study aims to explore whether the any two combination between ponatinib, deferoxamine and cyclosporine exerts a better cardioprotective effect on I/R injury than single medicine does. The H9c2 cells were subjected to 10 h of hypoxia (H) plus 4 h of reoxygenation (R) to establish H/R injury model. The effects of any two combination between ponatinib, deferoxamine and cyclosporine on H/R injury were examined. On this basis, a I/R injury model in rat hearts was established to focus on the effect of ponatinib, deferoxamine and their combination on myocardial I/R injury and the underlying mechanisms. In H/R-treated H9c2 cells, all three medicines can attenuate H/R injury (decrease in LDH release and necrosis percent). However, only the combination of ponatinib with deferoxamine exerted synergistic effect on reducing H/R injury, showing simultaneous suppression of necroptosis and ferroptosis. Expectedly, administration of ponatinib or deferoxamine either before or after ischemia could suppress necroptosis or ferroptosis in the I/R-treated rat hearts as they did in vitro, concomitant with a decrease in myocardial infarct size and creatine kinase release, and the combination therapy is more efficient than single medication. Based on these observations, we conclude that the combination of ponatinib with deferoxamine reduces myocardial I/R injury via simultaneous inhibition of necroptosis and ferroptosis. [Display omitted] [ABSTRACT FROM AUTHOR]

Initiation of necroptosis has been considered as a promising strategy for anticancer therapies, especially for eradicating apoptosis-resistant malignant cells. Jujubisode B is a natural saponins extracted from the seeds of Zizyphi Spinosi Semen, and possesses multiple pharmacological activities, including antianxiety, anti-inflammation, antiplatelet aggregation and induction of apoptosis. This study aims to explore the effect of jujuboside B on acute leukemic cells and the underlying mechanisms. Our results showed that jujuboside B inhibited leukemia cell growth in a dose-dependent manner and attenuated the clonogenic ability of U937 cells, concomitant with activation of RIPK1/RIPK3/MLKL pathway; these phenomena were evidently blocked by necroptosis inhibitor (Nec-1). With the help of Molecular Operating Environment (MOE) program, we identified that RIPK1, RIPK3 and MLKL are potential targets of jujuboside B. To the best of our knowledge, this is the first study to provide evidence that jujuboside B possesses antileukemic activity via a mechanism involving activation of RIPK1/RIPK3/MLKL pathway. [ABSTRACT FROM AUTHOR]

RIPK1/RIPK3/MLKL (Receptor-interacting protein kinase 1/Receptor-interacting protein kinase 3/Mixed lineage kinase domain-like protein) pathway-mediated necroptosis contributes to myocardial ischemia/reperfusion (I/R) injury, and Arctiin can prevent myocardial fibrosis and hypertrophy. This study aims to explore the effect of Arctiin on myocardial I/R injury and the underlying mechanisms. SD rat hearts or cardiomyocytes were subjected to I/R or hypoxia/reoxygenation (H/R) to establish the I/R or H/R injury model. The methods of biochemistry, PI/DAPI (propidium iodide/4′,6-Diamidino-2-Phenylindole) and H&E (Hematoxylin & eosin) staining were used to evaluate the I/R or H/R injury. The effects of Arctiin on necroptosis in I/R-treated hearts or H/R-treated cardiomyocytes were assessed. The results showed that Arctiin reduced myocardial I/R injury (decreases in myocardial infarction and creatine kinase release), concomitant with a decrease in levels of necroptosis-associated proteins (RIPK1/p-RIPK1, RIPK3/p-RIPK3 and MLKL/p-MLKL) in I/R-treated rat hearts. Consistently, the necrosis and LDH release in H/R-treated cardiomyocytes were attenuated in the presence of Arctiin, accompanied by suppression of necroptosis-relevant proteins. Furthermore, H/R-induced reactive oxygen species (ROS) generation and mitochondrial dysfunctions (increase in mitochondrial membrane potential and decrease in ATP production) were impaired by Arctiin. Using the program of the Molecular Operating Environment (MOE), we predict that RIPK1 and MLKL (but not RIPK3) might be the potential targets of Arctiin. Based on these observations, we conclude that Arctiin can protect the rat heart from I/R injury, and its beneficial effect is related to reduction of necroptosis via scavenging reactive oxygen species and restoring mitochondrial functions or targeting RIPK1 and/or MLKL. Image 1 • Arctiin protects rat heart from myocardial I/R injury. • Arctiin suppresses necroptosis in I/R-treated rat hearts. • Arctiin scavenge ROS and restore mitochondrial functions in cardiomyocyte. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunctions contribute to brain injury in ischemic stroke while disturbance of mitochondrial dynamics results in mitochondrial dysfunction. Mitochondrial E3 ubiquitin ligase 1 (Mul1) involves in regulation of mitochondrial fission and fusion. This study aims to explore whether Mul1 contributes to brain injury in ischemic stroke and the underlying mechanisms. First, a rat ischemic stroke model was established by middle cerebral artery occlusion (MCAO), which showed ischemic injuries (increase in neurological deficit score and infarct volume) and upregulation of Mul1 in brain tissues. Next, Mul1 siRNAs were injected intracerebroventricularly to knockdown Mul1 expression, which evidently attenuated brain injuries (decrease in neurological deficit score, infarct volume and caspase-3 activity), restored mitochondrial dynamics and functions (decreases in mitochondrial fission and cytochrome c release while increase in ATP production), and restored protein levels of dynamin-related protein 1 (Drp1, a mitochondrial fission protein) and mitofusin2 (Mfn2, a mitochondrial fusion protein) through suppressing their sumoylation and ubiquitination, respectively. Finally, PC12 cells were cultured under hypoxic condition to mimic the ischemic stroke. Consistently, knockdown of Mul1 significantly reduced hypoxic injuries (decrease in apoptosis and LDH release), restored protein levels of Drp1 and Mfn2, recovered mitochondrial dynamics and functions (decreases in mitochondrial fission, mitochondrial membrane potential, reactive oxygen species production and cytochrome c release while increase in ATP production). Based on these observations, we conclude that upregulation of Mul1 contributes to brain injury in ischemic stroke rats and disturbs mitochondrial dynamics through sumoylation of Drp1 and ubiquitination of Mfn2. Image 1 [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated that NADPH oxidase (NOX)/vascular peroxidase (VPO1) pathway – mediated oxidative stress plays an important role in the pathogenesis of multiple cardiovascular diseases. This study aims to evaluate the correlation between NOX/VPO1 pathway and endothelial progenitor cells (EPCs) dysfunctions in hypoxia-induced pulmonary hypertension (PH). The rats were exposed to 10% hypoxia for 3 weeks to establish a PH model, which showed increases in right ventricle systolic pressure, right ventricular and pulmonary vascular remodeling, acceleration in apoptosis and impairment in functions of the peripheral blood derived - EPCs (the reduced abilities in adhesion, migration and tube formation), accompanied by up-regulation of NOX (NOX2 and NOX4) and VPO1. Next, normal EPCs were cultured under hypoxia to induce apoptosis in vitro. Consistent with the in vivo findings, hypoxia enhanced the apoptosis and dysfunctions of EPCs concomitant with an increase in NOX and VPO1 expression, hydrogen peroxide (H 2 O 2) and hypochlorous acid (HOCl) production; these phenomena were attenuated by NOX2 or NOX4 siRNA. Knockdown of VPO1 showed similar results to that of NOX siRNA except no effect on NOX expression and H 2 O 2 production. Based on these observations, we conclude that NOX/VPO1 pathway-derived reactive oxygen species promote the oxidative injury and dysfunctions of EPCs in PH, which may contribute to endothelial dysfunctions in PH. Image 1 [ABSTRACT FROM AUTHOR]