Alamandine attenuates sepsis-associated cardiac dysfunction via inhibiting MAPKs signaling pathways

Klotho alleviates sepsis-associated myocardial inflammation and apoptosis

Klotho (KL) protects against various pathological phenotypes. The present study was designed to investigate the effect of KL on sepsis-associated cardiac dysfunction, and whether KL modulated sepsis-associated cardiac dysfunction via oxidative stress and apoptosis. Experiments were carried out in mice treated with lipopolysaccharide (LPS) to induce the septic model. The expression of KL was reduced in the heart of septic mice induced by LPS administration. The cardiac dysfunction of septic mice was deteriorated after KL KO, and was alleviated by KL upregulation. The inflammatory factors of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6 were increased in the heart after LPS treatment, and these increases were further enhanced in KL deficiency mice, and were alleviated in KL overexpressed mice. The apoptosis biomarkers of B-cell lymphoma 2 (Bcl2) and Bcl2-associated X protein (Bax) levels were changed in the heart of septic mice, which were exacerbated by KL KO and were ameliorated by KL overexpression. These results indicated that KL involved in the regulation of sepsis-induced cardiac dysfunction via alleviating inflammation and apoptosis. Upregulation KL may be a therapeutic strategy to improve cardiac function in septic patients in the future.

ACE2 alleviates sepsis-induced cardiomyopathy through inhibiting M1 macrophage via NF-κB/STAT1 signals

Angiotensin-converting enzyme 2 (ACE2), a crucial element of the renin-angiotensin system (RAS), metabolizes angiotensin II into Ang (1-7), which then combines with the Mas receptor (MasR) to fulfill its protective role in various diseases. Nevertheless, the involvement of ACE2 in sepsis-induced cardiomyopathy (SIC) is still unexplored. In this study, our results revealed that CLP surgery dramatically impaired cardiac function accompanied with disruption of the balance between ACE2-Ang (1-7) and ACE-Ang II axis in septic heart tissues. Moreover, ACE2 knockin markedly alleviated sepsis induced RAS disorder, cardiac dysfunction and improved survival rate in mice, while ACE2 knockout significantly exacerbates these outcomes. Adoptive transfer of bone marrow cells and in vitro experiments showed the positive role of myeloid ACE2 by mitigating oxidative stress, inflammatory response, macrophage polarization and cardiomyocyte apoptosis by blocking NF-κB and STAT1 signals. However, the beneficial impacts were nullified by MasR antagonist A779. Collectively, these findings showed that ACE2 alleviated SIC by inhibiting M1 macrophage via activating the Ang (1-7)-MasR axis, highlight that ACE2 might be a promising target for the management of sepsis and SIC patients.

Corylin alleviated sepsis-associated cardiac dysfunction via attenuating inflammation through downregulation of microRNA-214-5p

Background

Corylin, a natural flavonoid, is isolated from the fruit of Psoralea corylifolia L. Nevertheless, the effect of corylin on sepsis-associated cardiac dysfunction is still unclear. The purpose of this study is to determine the role and mechanism of corylin in sepsis related cardiac dysfunction.

Methods

Experiments were carried out on mice with lipopolysaccharide (LPS) or sepsis induced by cecal ligation and puncture (CLP) or myocardial cell sepsis induced by LPS.

Results

Administration of corylin improved cardiac dysfunction induced by LPS or CLP in mice. Corylin inhibited the increases of interleukin-1 (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α in the heart of mice with LPS or CLP. LPS elevated the levels of IL-1β, IL-6 and TNF-α in cardiomyocytes, which were inhibited by corylin treatment. Corylin attenuated the increases of microRNA (miRNA)-214-5p in the heart of mice with LPS, CLP, LPS-treated NRCMs, H9c2 and AC16 cells. Administration of miRNA-214-5p agomiR reversed the improving effects of corylin on the damaged cardiac function and the increases of IL-1β, IL-6 and TNF-α in mice treated with LPS.

Conclusion

These outcomes indicated that corylin improved sepsis-associated cardiac dysfunction by inhibiting inflammation. And corylin inhibited inflammation of sepsis by decreasing miRNA-214-5p. Downregulation of miRNA-214-5p improved sepsis-associated cardiac dysfunction and inhibited inflammatory factors.

High-dose Vitamin C injection ameliorates against sepsis-induced myocardial injury by anti-apoptosis, anti-inflammatory and pro-autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR signaling pathways in rats

AIMS

This study aimed to evaluate the effects of VC on SIMI in rats.

METHODS

In this study, the survival rate of high dose VC for SIMI was evaluated within 7 days. Rats were randomly assigned to three groups: Sham group, CLP group, and high dose VC (500 mg/kg i.v.) group. The animals in each group were treated with drugs for 1 day, 3 days or 5 days, respectively. Echocardiography, myocardial enzymes and HE were used to detect cardiac function. IL-1β, IL-6, IL-10 and TNF-α) in serum were measured using ELISA kits. Western blot was used to detect proteins related to apoptosis, inflammation, autophagy, MAPK, NF-κB and PI3K/Akt/mTOR signaling pathways.

RESULTS

High dose VC improved the survival rate of SIMI within 7 days. Echocardiography, HE staining and myocardial enzymes showed that high-dose VC relieved SIMI in rats in a time-dependent manner. And compared with CLP group, high-dose VC decreased the expressions of pro-apoptotic proteins, while increased the expression of anti-apoptotic protein. And compared with CLP group, high dose VC decreased phosphorylation levels of Erk1/2, P38, JNK, NF-κB and IKK α/β in SIMI rats. High dose VC increased the expression of the protein Beclin-1 and LC3-II/LC3-I ratio, whereas decreased the expression of P62 in SIMI rats. Finally, high dose VC attenuated phosphorylation of PI3K, AKT and mTOR compared with the CLP group.

SIGNIFICANCE

Our results showed that high dose VC has a good protective effect on SIMI after continuous treatment, which may be mediated by inhibiting apoptosis and inflammatory, and promoting autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR pathway.

Counter-regulatory RAS peptides: new therapy targets for inflammation and fibrotic diseases?

The renin-angiotensin system (RAS) is an important cascade of enzymes and peptides that regulates blood pressure, volume, and electrolytes. Within this complex system of reactions, its counter-regulatory axis has attracted attention, which has been associated with the pathophysiology of inflammatory and fibrotic diseases. This review article analyzes the impact of different components of the counter-regulatory axis of the RAS on different pathologies. Of these peptides, Angiotensin-(1-7), angiotensin-(1-9) and alamandine have been evaluated in a wide variety of in vitro and in vivo studies, where not only they counteract the actions of the classical axis, but also exhibit independent anti-inflammatory and fibrotic actions when binding to specific receptors, mainly in heart, kidney, and lung. Other functional peptides are also addressed, which despite no reports associated with inflammation and fibrosis to date were found, they could represent a potential target of study. Furthermore, the association of agonists of the counter-regulatory axis is analyzed, highlighting their contribution to the modulation of the inflammatory response counteracting the development of fibrotic events. This article shows an overview of the importance of the RAS in the resolution of inflammatory and fibrotic diseases, offering an understanding of the individual components as potential treatments.

Alamandine attenuates oxidative stress in the right carotid following transverse aortic constriction in mice

OBJECTIVE

Pressure overload can result in significant changes to the structure of blood vessels, a process known as vascular remodeling. High levels of tension can cause vascular inflammation, fibrosis, and structural alterations to the vascular wall. Prior research from our team has demonstrated that the oral administration of alamandine can promote vasculoprotective effects in mice aorta that have undergone transverse aortic constriction (TAC). Furthermore, changes in local hemodynamics can affect the right and left carotid arteries differently after TAC. Thus, in this study, we aimed to assess the effects of alamandine treatment on right carotid remodeling and the expression of oxidative stress-related substances induced by TAC.

METHODS AND RESULTS

Male C57BL/6 mice were categorized into three groups: Sham, TAC, and TAC treated with alamandine (TAC+ALA). Alamandine treatment was administered orally by gavage (30 µg/kg/day), starting three days before the surgery, and continuing for a period of fourteen days. Morphometric analysis of hematoxylin and eosin-stained sections revealed that TAC induced hypertrophic and positive remodeling in the right carotid artery. Picrosirius Red staining also demonstrated an increase in total collagen deposition in the right carotid artery due to TAC-induced vascular changes. Alamandine treatment effectively prevented the increase in reactive oxygen species production and depletion of nitric oxide levels, which were induced by TAC. Finally, alamandine treatment was also shown to prevent the increased expression of nuclear factor erythroid 2-related factor 2 and 3-nitrotyrosine that were induced by TAC.

CONCLUSION

Our results suggest that alamandine can effectively attenuate pathophysiological stress in the right carotid artery of animals subjected to TAC.

The role of TLR4/MyD88/NF-κB in the protective effect of ulinastatin on the intestinal mucosal barrier in mice with sepsis

OBJECTIVE

To investigate the effect of the TLR4/MyD88/NF-κB (Toll-like receptor 4/myeloid differentiation factor/nuclear factor kappa B) signalling pathway on the protective effect of ulinastatin on the intestinal mucosal barrier in mice with sepsis.

METHODS

A mouse model of sepsis was established by classical caecal ligation and perforation. Forty-four SPF C57BL/6 mice were randomly divided into the following four groups with 11 mice in each group: the control group (Con group), ulinastatin group (Uti group), Uti + LPS (lipopolysaccharide, LPS) group (Uti + LPS group) and LPS group. Mice in the Con group and Uti group received saline or ulinastatin injected 2 h after modelling; Mice in the Uti + LPS group received LPS injected 0 h after modelling, other procedures were the same as in the Uti group; Mice in the LPS group received LPS only. At 48 h after surgery, the levels of TNF-α (tumour necrosis factor-α, TNF-α), IL-6 (interleukin-6, IL-6) and IL-1β (interleukin-1β, IL-1β) in vein, and the expression of TLR4, MyD88 and NF-κB mRNA in small intestinal mucosa tissues using ELISA and RT‒PCR.

RESULTS

The pathological specimens showed increased inflammatory injury in the Con and LPS groups, while these injuries and changes improved in the Uti group. The scores of intestinal mucosal injury at 48 h of Uti injection were significantly lower than those of the Con group (P < 0.001), while the scores of intestinal mucosal injury of Uti + LPS were significantly higher than those of the Uti group (P = 0.044). The expression of TNF-α, IL-6 and IL-1β in the Uti decreased significantly at 48 h after surgery than that in the Con group (P = 0.001, P = 0.014, P = 0.004), while the expression of TNF-α, IL-6 and IL-1β in the Uti + LPS group increased significantly after surgery than that in the Uti group (P = 0.026, P = 0.040, P = 0.039). The expression of TLR4, MyD88 and NF-κB mRNA in the Uti group decreased significantly compared with that in the Con group (P = 0.001, P = 0.021, P = 0.007), while the expression of TLR4, MyD88 and NF-κB mRNA in the Uti + LPS group was higher than that in the Uti group (P = 0.023, P = 0.040, P = 0.045).

CONCLUSION

These findings indicate that the protective effect of ulinastatin on the intestinal mucosal barrier against sepsis may be mediated through the TLR4/MyD88/NF-κB pathway.

Alamandine treatment prevents LPS-induced acute renal and systemic dysfunction with multi-organ injury in rats via inhibiting iNOS expression

Sepsis is defined as the dysregulated immune response leading to multi-organ dysfunction and injury. Sepsis-induced acute kidney injury is a significant contributor to morbidity and mortality. Alamandine (ALA) is a novel endogenous peptide of the renin-angiotensin-aldosterone system. It is known for its anti-inflammatory and anti-apoptotic effects, but its functional and vascular effects on sepsis remain unclear. We aimed to investigate the effects of ALA, as a pre- and post-treatment agent, on lipopolysaccharide (LPS)-induced systemic and renal dysfunction and injury in the LPS-induced endotoxemia model in rats via functional, hemodynamic, vascular, molecular, biochemical, and histopathological evaluation. 10 mg/kg intraperitoneal LPS injection caused both hepatic and renal injury, decreased blood flow in several organs, and renal dysfunction at 20 h in Sprague-Dawley rats. Our results showed that ALA treatment ameliorated systemic and renal inflammation, reduced inflammatory cytokines, prevented the enhancement of the mortality rate, reversed vascular dysfunction, corrected decreased blood flows in several organs, and reduced renal and hepatic injury via inhibiting iNOS (inducible nitric oxide synthase) and caspase expressions in the kidney. In addition, expressions of different ALA-related receptors showed alterations in this model, and ALA treatment reversed these alterations. These data suggest that ALA's systemic and renal protective effects are achieved through its anti-inflammatory, anti-pyroptotic, and anti-apoptotic effects on hemodynamic and vascular functions via reduced iNOS expression.

S100A8/A9: An emerging player in sepsis and sepsis-induced organ injury

Sepsis, the foremost contributor to mortality in intensive care unit patients, arises from an uncontrolled systemic response to invading infections, resulting in extensive harm across multiple organs and systems. Recently, S100A8/A9 has emerged as a promising biomarker for sepsis and sepsis-induced organ injury, and targeting S100A8/A9 appeared to ameliorate inflammation-induced tissue damage and improve adverse outcomes. S100A8/A9, a calcium-binding heterodimer mainly found in neutrophils and monocytes, serves as a causative molecule with pro-inflammatory and immunosuppressive properties, which are vital in the pathogenesis of sepsis. Therefore, improving our comprehension of how S100A8/A9 acts as a pathological player in the development of sepsis is imperative for advancing research on sepsis. Our review is the first-to the best of our knowledge-to discuss the biology of S100A8/A9 and its release mechanisms, summarize recent advances concerning the vital roles of S100A8/A9 in sepsis and the consequential organ damage, and underscore its potential as a promising diagnostic biomarker and therapeutic target for sepsis.

The renin-angiotensin-aldosterone system (RAAS) signaling pathways and cancer: foes versus allies

The renin-angiotensin-aldosterone system (RAAS), is an old system with new fundamental roles in cancer biology which influences cell growth, migration, death, and metastasis. RAAS signaling enhances cell proliferation in malignancy directly and indirectly by affecting tumor cells and modulating angiogenesis. Cancer development may be influenced by the balance between the ACE/Ang II/AT1R and the ACE2/Ang 1-7/Mas receptor pathways. The interactions between Ang II/AT1R and Ang I/AT2R as well as Ang1-7/Mas and alamandine/MrgD receptors in the RAAS pathway can significantly impact the development of cancer. Ang I/AT2R, Ang1-7/Mas, and alamandine/MrgD interactions can have anticancer effects while Ang II/AT1R interactions can be involved in the development of cancer. Evidence suggests that inhibitors of the RAAS, which are conventionally used to treat cardiovascular diseases, may be beneficial in cancer therapies.Herein, we aim to provide a thorough description of the elements of RAAS and their molecular play in cancer. Alongside this, the role of RAAS components in sex-dependent cancers as well as GI cancers will be discussed with the hope of enlightening new venues for adjuvant cancer treatment.

Targeting of cold-inducible RNA-binding protein alleviates sepsis via alleviating inflammation, apoptosis and oxidative stress in heart

A systemic inflammatory response is observed in patients undergoing shock and sepsis. This study aimed to explore the effects of cold-inducible RNA-binding protein (CIRP) on sepsis-associated cardiac dysfunction and the underlying mechanism. In vivo and in vitro lipopolysaccharide (LPS)-induced sepsis models were established in mice and neonatal rat cardiomyocytes (NRCMs), respectively. CRIP expressions were increased in the mouse heart and NRCMs treated with LPS. CIRP knockdown alleviated LPS-induced decreases of left ventricular ejection fraction and fractional shortening. CIRP downregulation attenuated the increases of inflammatory factors in the LPS-induced septic mouse heart, and NRCMs. The enhanced oxidative stress in the LPS-induced septic mouse heart and NRCMs was suppressed after CIRP knockdown. By contrast, CIRP overexpression yielded the opposite results. Our current study indicates that the knockdown of CIRP protects against sepsis-induced cardiac dysfunction through alleviating inflammation, apoptosis and oxidative stress of cardiomyocytes.

Nuclear import of Mas-related G protein-coupled receptor member D induces pathological cardiac remodeling

Alamandine (Ala), a ligand of Mas-related G protein-coupled receptor, member D (MrgD), alleviates angiotensin II (AngII)-induced cardiac hypertrophy. However, the specific physiological and pathological role of MrgD is not yet elucidated. Here, we found that MrgD expression increased under various pathological conditions. Then, MrgD knockdown prevented AngII-induced cardiac hypertrophy and fibrosis via inactivating Gα_i-mediacted downstream signaling pathways, including the phosphorylation of p38 (p-P38), while MrgD overexpression induced pathological cardiac remodeling. Next, Ala, like silencing MrgD, exerted its cardioprotective effects by inhibiting Ang II-induced nuclear import of MrgD. MrgD interacted with p-P38 and promoted its entry into the nucleus under Ang II stimulation. Our results indicated that Ala was a blocking ligand of MrgD that inhibited downstream signaling pathway, which unveiled the promising cardioprotective effect of silencing MrgD expression on alleviating cardiac remodeling. Video Abstract.

Honokiol alleviates sepsis-associated cardiac dysfunction via attenuating inflammation, apoptosis and oxidative stress

OBJECTIVE

Honokiol, a natural active compound extracted from Chinese herbal medicine, can ameliorate acute lung and kidney injury of sepsis. This study was to explore the effects of honokiol on sepsis-associated cardiac dysfunction and the underlying mechanism.

METHODS

Septic mice were induced by cecal ligation and puncture (CLP) or lipopolysaccharide (LPS), and septic HL-1 or AC16 cells were induced by LPS.

RESULTS

Honokiol improved the survival and alleviated cardiac dysfunction in mice with CLP-induced sepsis. Honokiol inhibited the increased interleukin (IL) 1-β, IL-6 and tumour necrosis factor (TNF)-α in the serum and heart of CLP- and LSP-induced septic mice. Honokiol treatment reversed the increased levels of IL1-β, IL-6 and TNF-α in LPS-induced HL-1 cells. Honokiol treatment also decreased the elevated levels of IL1-β, IL-6 and TNF-α in LPS-induced AC16 cells. The increased cardiac apoptosis in CLP- and LPS-induced septic mice was alleviated by honokiol. The enhancement of oxidative stress in the heart of CLP- and LPS-induced septic mice was suppressed after honokiol administration.

CONCLUSION

These results showed that honokiol could ameliorate sepsis-associated cardiac dysfunction via attenuating inflammation, apoptosis, and oxidative stress. Honokiol is a prospective drug for sepsis-associated heart damage in the future.

An overview of alamadine/MrgD signaling and its role in cardiomyocytes

The renin-angiotensin system (RAS) is a classical hormonal system involved in a myriad of cardiovascular functions. This system is composed of many different peptides that act in the heart through different receptors. One of the most important of these peptides is angiotensin II, which in pathological conditions triggers a set of actions that lead to heart failure. On the other hand, another RAS peptide, angiotensin-(1-7) is well known to develop powerful therapeutic effects in many forms of cardiac diseases. In the last decade, two new components of RAS were described, the heptapeptide alamandine and its receptor, the Mas-related G protein-coupled receptor member D (MrgD). Since then, great effort was made to characterize their physiological and pathological function in the heart. In this review, we summarize the latest insights about the actions of alamandine/MrgD axis in the heart, with particular emphasis in the cardiomyocyte. More specifically, we focused on their antihypertrophic and contractility effects, and the related molecular events activated in the cardiomyocyte.

Activation of the Mas receptors by AVE0991 and MrgD receptor using alamandine to limit the deleterious effects of Ang II-induced hypertension

The MrgD receptor agonist, alamandine (ALA) and Mas receptor agonist, AVE0991 have recently been identified as protective components of the renin-angiotensin system. We evaluated the effects of ALA and AVE0991 on cardiovascular function and remodeling in angiotensin (Ang) II-induced hypertension in rats. Sprague Dawley rats were subject to 4-week subcutaneous infusions of Ang II (80 ng/kg/min) or saline after which they were treated with ALA (50 μg/kg), AVE0991 (576 μg/kg), or ALA+AVE0991 during the last 2 weeks. Systolic blood pressure (SBP) and heart rate (HR) values were recorded with tail-cuff plethysmography at 1, 15, and 29 days post-treatment. After euthanization, the heart and thoracic aorta were removed for further analysis and vascular responses. SBP significantly increased in the Ang II group when compared to the control group. Furthermore, Ang II also caused an increase in cardiac and aortic cyclophilin-A (CYP-A), monocyte chemoattractant protein-1 (MCP-1), and cardiomyocyte degeneration but produced a decrease in vascular relaxation. HR, matrix metalloproteinase-2 and -9, NADPH oxidase-4, and lysyl oxidase levels were comparable among groups. ALA, AVE0991, and the drug combination produced antihypertensive effects and alleviated vascular responses. The inflammatory and oxidative stress related to cardiac MCP-1 and CYP-A levels decreased in the Ang II+ALA+AVE0991 group. Vascular but not cardiac angiotensin-converting enzyme-2 levels decreased with Ang II administration but were similar to the Ang II+ALA+AVE0991 group. Our experimental data showed the combination of ALA and AVE0991 was found beneficial in Ang II-induced hypertension in rats by reducing SBP, oxidative stress, inflammation, and improving vascular responses.

Counter-regulatory renin-angiotensin system in hypertension: Review and update in the era of COVID-19 pandemic

Cardiovascular disease is the major cause of mortality and disability, with hypertension being the most prevalent risk factor. Excessive activation of the renin-angiotensin system (RAS) under pathological conditions, leading to vascular remodeling and inflammation, is closely related to cardiovascular dysfunction. The counter-regulatory axis of the RAS consists of angiotensin-converting enzyme 2 (ACE2), angiotensin (1-7), angiotensin (1-9), alamandine, proto-oncogene Mas receptor, angiotensin II type-2 receptor and Mas-related G protein-coupled receptor member D. Each of these components has been shown to counteract the effects of the overactivated RAS. In this review, we summarize the latest insights into the complexity and interplay of the counter-regulatory RAS axis in hypertension, highlight the pathophysiological functions of ACE2, a multifunctional molecule linking hypertension and COVID-19, and discuss the function and therapeutic potential of targeting this counter-regulatory RAS axis to prevent and treat hypertension in the context of the current COVID-19 pandemic.

Alamandine: A promising treatment for fibrosis

Angiotensin (Ang) II, the main active member of the renin angiotensin system (RAS), is essential for the maintenance of cardiovascular homeostasis. However, hyperactivation of the RAS causes fibrotic diseases. Ang II has pro-inflammatory actions, and moreover activates interstitial fibroblasts and/or dysregulates extracellular matrix degradation. The discovery of new RAS pathways has revealed the complexity of this system. Among the RAS peptides, alamandine (ALA, Ala¹ Ang 1-7) has been identified in humans, rats, and mice, with protective actions in different pathological conditions. ALA has similar effects to its well-known congener, Ang-(1-7), as a vasodilator, anti-inflammatory, and antifibrotic. Its protective role against cardiovascular diseases is well-reviewed in the literature. However, the protective actions of ALA in fibrotic conditions have been little explored. Therefore, in this article, we review the ability of ALA to modulate the inflammatory process and collagen deposition, to serve as an antioxidant, and to mediate protection against functional disorders. In this scenario, we also explore ALA as a promising therapy for pulmonary fibrosis after COVID-19 infection.

Alamandine alleviated heart failure and fibrosis in myocardial infarction mice

Alamandine (Ala) is the newest identified peptide of the renin-angiotensin system and has protective effect on myocyte hypertrophy. However, it is still unclear whether Ala can alleviate heart failure (HF). The aim of this study was to explore the effects of Ala on HF and the related cardiac fibrosis, and to probe the mechanism. HF model was induced by myocardial infarction (MI) in mice. Four weeks after MI, Ala was administrated by intraperitoneal injection for two weeks. Ala injection significantly improved cardiac dysfunction of MI mice in vivo. The cardiac fibrosis and the related biomarkers were attenuated after Ala administration in HF mice in vivo. The increases of collagen I, alpha-smooth muscle actin and transforming growth factor-beta induced by oxygen–glucose deprivation (OGD) in neonatal rat cardiac fibroblasts (NRCFs) were inhibited by Ala treatment in vitro. The biomarkers of apoptosis were elevated in NRCFs induced by OGD, which were attenuated after treating with Ala in vitro. The enhancement of oxidative stress in the heart of MI mice or in the NRCFs treated with OGD was suppressed by treating with Ala in vivo and in vitro. These effects of Ala were reversed by tBHP, an exogenous inducer of oxidative stress in vitro. These results demonstrated that Ala could alleviate cardiac dysfunction and attenuate cardiac fibrosis via inhibition of oxidative stress.

Alamandine, a new member of the renin-angiotensin system (RAS), attenuates collagen-induced arthritis in mice via inhibiting cytokine secretion in synovial fibroblasts

Alamandine is a novel component of the renin-angiotensin system (RAS) as well as an important biologically active peptide. It has predominantly been studied in cardiovascular context. However, its role in rheumatoid arthritis (RA) remains unknown. Here we illustrated its effects on inflammatory cytokines production by synovial fibroblasts from RA and pathological changes in collagen-induced arthritis (CIA) mice. Alamandine (0.1, 1 and 10 µg/ml) did not affect the survival of the synovial fibroblasts, but decreased the migration and proinflammatory cytokines expression in TNF-α (10 ng/ml) stimulated cells in vitro. Additionally, alamandine selectively decreased phosphorylated-JNK expression induced by TNF-a stimulation in RA FLS. DBA/1 J mice were induced arthritis by a primary injection with an emulsion of bovine type II collagen (CII) and complete Freund's adjuvant (day 0) and a booster injection of CII in incomplete Freund's adjuvant (day 21). Mice were then given alamandine intraperitoneally in saline (50 μg/kg/day) from days 21-42. Histology and multiplex immunobead assay showed that alamandine treatment inhibited the development of arthritis and reduced the joint damage. This effect was accompanied by the reduced inflammatory cytokines (IL-6, IL-23, IFN-γ) mRNA expression in local joints, the decreased TNF-α, IL-6, IL-17 and the increased IL-10 levels in the serum from alamandine administrated CIA mice. In conclusion, alamandine attenuates the development of arthritis by suppressing inflammatory cytokines expression in RA synovial fibroblasts via MAPK signaling pathway, suggesting a potential therapeutic role for RA.

LongShengZhi alleviated cardiac remodeling via upregulation microRNA-150-5p with matrix metalloproteinase 14 as the target

ETHNOPHARMACOLOGICAL RELEVANCE

LongShengZhi capsule (LSZ), a traditional Chinese medicine, is used for treatment of patients with vascular diseases. LSZ reduced doxorubicin-induced heart failure by reducing production of reactive oxygen species and inhibiting inflammation and apoptosis.

AIM OF THE STUDY

This study was to explore whether LSZ could alleviate cardiac remodeling via upregulation of microRNA (miR)-150-5p and the downstream target. Cardiac remodeling was induced by Ang II in vivo and in vitro.

RESULTS

LSZ attenuated Ang II-induced cardiac hypertrophy and fibrosis in rats, and in primary cardiomyocytes (CMs) and primary cardiac fibroblasts (CFs). MiR-150-5p was downregulated in Ang II-induced rat heart, CMs and CFs, and these decreases were reserved by LSZ. In vivo overexpression of miR-150-5p by transfection of miR-150-5p agomiR protected Ang II-induced cardiac hypertrophy and fibrosis in rats. Meanwhile, its overexpression also reversed Ang II-induced upregulation of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and β-myosin heavy chain (β-MHC) in rat hearts and primary CMs, as well as upregulation of collagen I, collagen III and transforming growth factor-β (TGF-β) in rat hearts and primary CFs. Matrix metalloproteinase 14 (MMP14) was validated as the target gene of miR-150-5p, which was overexpressed in Ang II-induced rat heart, rat primary CMs and primary CFs. Notably, overexpression of MMP14 induced cardiac remodeling, and reversed the protective role of miR-150-5p in downregulating Ang II-induced upregulation of hypertrophy and fibrosis markers in vitro.

CONCLUSION

Collectively, LSZ protects Ang II-induced cardiac dysfunction and remodeling via upregulation of miR-150-5p to target MMP14. Administration of LSZ, upregulation of miR-150-5p or targeting of MMP14 may be strategies for cardiac remodeling therapy.

Effects of thymoquinone against angiotensin II‑induced cardiac damage in apolipoprotein E‑deficient mice

Herbal medicines have attracted much attention in recent years and are increasingly being used as alternatives to pharmaceutical medicines. Thymoquinone (TQ) is one of the most active ingredients in Nigella sativa seeds, which has several beneficial properties, including anti‑inflammatory, anti‑oxidative stress, anti‑hypertensive, anti‑apoptotic and free radical‑scavenging effects. Angiotensin II (Ang II) is involved in cardiovascular diseases. The present study aimed to investigate the potential protective effects of TQ against Ang II‑induced cardiac damage in apolipoprotein E‑deficient (ApoE‑/‑) mice. Briefly, 8‑week‑old male ApoE‑/‑ mice were randomly divided into four groups: Control, TQ, Ang II and Ang II + TQ groups. Osmotic minipumps, filled with either a saline vehicle or an Ang II solution (1,000 ng/kg/min), were implanted in ApoE‑/‑ mice for up to 4 weeks. The serum levels of high‑sensitivity C‑reactive protein (hs‑CRP) and histopathological alterations in heart tissue were assessed. In addition, the mRNA and protein expression levels of molecules associated with fibrosis (collagen I and III), oxidative stress and apoptosis (Nox4 and p53), and inflammation [tumor necrosis factor (TNF)‑α, interleukin (IL)‑1β and IL‑6] were analyzed by reverse transcription‑quantitative PCR (RT‑qPCR) and western blotting. In the in vitro study, H9c2 cells were incubated with different concentrations of Ang II, and the expression levels of pro‑inflammatory cytokines were evaluated using RT‑qPCR, whereas the protein expression levels of phosphorylated‑extracellular signal‑regulated kinase (p‑ERK) were determined using western blotting. Western blotting was also performed to detect the expression levels of collagen I, collagen III, Nox4 and p53 in H9c2 cells. The results revealed that TQ inhibited the Ang II‑induced increases in serum hs‑CRP levels. TQ also significantly inhibited the high levels of TNF‑α, IL‑1β, IL‑6, collagen I, collagen III, Nox4 and p53 in Ang II‑treated mice. Furthermore, TQ protected against Ang II‑induced cardiac damage by inhibiting inflammatory cell infiltration, proinflammatory cytokine expression, fibrosis, oxidative stress and apoptosis by suppressing activation of the p‑ERK signaling pathway. In conclusion, TQ could be considered a potential therapeutic agent for Ang II‑induced cardiac damage.

Alamandine Induces Neuroprotection in Ischemic Stroke Models

Background and Objective:

Stroke, a leading cause of mortality and disability, characterized by neuronal death, can be induced by a reduction or interruption of blood flow. In this study, the role of Alamandine, a new peptide of the renin-angiotensin system, was evaluated in in-vitro and in-vivo brain ischemia models.

Method:

In the in-vitro model, hippocampal slices from male C57/Bl6 mice were placed in a glucose-free aCSF solution and bubbled with 95% N2 and 5% CO2 to mimic brain ischemia. An Alamandine concentration-response curve was generated to evaluate cell damage, glutamatergic excitotoxicity, and cell death. In the in-vivo model, cerebral ischemia/reperfusion was induced by bilateral occlusion of common carotid arteries (BCCAo-untreated) in SD rats. An intracerebroventricular injection of Alamandine was given 20–30 min before BCCAo. Animals were subjected to neurological tests 24 h and 72 h after BCCAo. Cytokine levels, oxidative stress markers, and immunofluorescence were assessed in the brain 72 h after BCCAo.

Results:

Alamandine was able to protect brain slices from cellular damage, excitotoxicity and cell death. When the Alamandine receptor was blocked, protective effects were lost. ICV injection of Alamandine attenuated neurological deficits of animals subjected to BCCAo and reduced the number of apoptotic neurons/cells. Furthermore, Alamandine induced anti-inflammatory effects in BCCAo animals as shown by reductions in TNFα, IL-1β, IL-6, and antioxidant effects through attenuation of the decreased SOD, catalase, and GSH activities in the brain.

Conclusion:

This study showed, for the first time, a neuroprotective role for Alamandine in different ischemic stroke models.

Alamandine alleviates hypertension and renal damage via oxidative-stress attenuation in Dahl rats

Alamandine (Ala) is a novel member of the renin-angiotensin-system (RAS) family. The present study aimed to explore the effects of Ala on hypertension and renal damage of Dahl salt-sensitive (SS) rats high-salt diet-induced, and the mechanisms of Ala on renal-damage alleviation. Dahl rats were fed with high-salt diets to induce hypertension and renal damage in vivo, and HK-2 cells were treated with sodium chloride (NaCl) to induce renal injury in vitro. Ala administration alleviated the high-salt diet-induced hypertension, renal dysfunction, and renal fibrosis and apoptosis in Dahl SS rats. The HK-2 cells' damage, and the increases in the levels of cleaved (c)-caspase3, c-caspase8, and c-poly(ADP-ribose) polymerase (PARP) induced by NaCl were inhibited by Ala. Ala attenuated the NaCl-induced oxidative stress in the kidney and HK-2 cells. DETC, an inhibitor of SOD, reversed the inhibitory effect of Ala on the apoptosis of HK-2 cells induced by NaCl. The NaCl-induced increase in the PKC level was suppressed by Ala in HK-2 cells. Notably, PKC overexpression reversed the moderating effects of Ala on the NaCl-induced apoptosis of HK-2 cells. These results show that Ala alleviates high-salt diet-induced hypertension and renal dysfunction. Ala attenuates the renal damage via inhibiting the PKC/reactive oxygen species (ROS) signaling pathway, thereby suppressing the apoptosis in renal tubular cells.

Yin Yang 1 (YY1)-induced long intergenic non-protein coding RNA 472 (LINC00472) aggravates sepsis-associated cardiac dysfunction via the micro-RNA-335-3p (miR-335-3p)/Monoamine oxidase A (MAOA) cascade

As a leading complication of sepsis, sepsis-induced cardiac dysfunction (SICD) contributed to the high mortality of patients with sepsis. Long non-coding RNA (LncRNA) LINC00472 has been reported to be in sepsis-induced disease. Nonetheless, its biological function and underlying molecular in SICD remain largely unknown. In this study, in vivo and in vitro SICD models were established via LPS treatment. H&E staining was employed for the evaluation of myocardial injury. ELISA assay was performed to detect cardiac Troponin I (cTnI), creatine kinase-MB (CK-MB), interleukin (IL)-1β, and tumor necrosis factor-α (TNF-α) levels. Cardiomyocyte viability and apoptosis were assessed via CCK-8 and flow cytometry assays. The transcriptional regulation of YY1 on LINC00472 was demonstrated via ChIP assay. Besides, the interaction between YY1 and LINC00472, as well as the association between miR-335-3p and LINC00472 or MAOA were verified via luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Herein, highly expressed LINC00472 was observed in both in vivo and in vitro SICD models. LINC00472 knockdown substantially attenuated LPS-induced inhibition on cardiomyocyte viability and reversed cardiomyocyte apoptosis and inflammatory response mediated by LPS treatment. YY1 induced LINC00472 upregulation, thereby promoting cardiomyocyte dysfunction induced by LPS. In addition, MAOA upregulation or miR-335-3p inhibition could partly reverse the suppressive effect on LPS-induced cardiomyocyte dysfunction mediated by LINC00472 knockdown. Based on our results, it seemed that YY1-activated LINC00472 might contribute to SICD progression via the miR-335-3p/MAOA pathway.

Alamandine: Potential Protective Effects in SARS-CoV-2 Patients

Coronavirus disease 2019 (COVID-19) can occur due to contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has no confined treatment and, consequently, has high hospitalization and mortality rates. Moreover, people who contract COVID-19 present systemic inflammatory spillover. It is now known that COVID-19 pathogenesis is linked to the renin-angiotensin system (RAS). COVID-19 invades host cells via the angiotensin-converting enzyme 2 (ACE2) receptor—as such, an individual's susceptibility to COVID-19 increases alongside the upregulation of this receptor. COVID-19 has also been associated with interstitial pulmonary fibrosis, which leads to acute respiratory distress, cardiomyopathy, and shock. These outcomes are thought to result from imbalances in angiotensin (Ang) II and Ang-(1-7)/alamandine activity. ACE2, Ang-(1-7), and alamandine have potent anti-inflammatory properties, and some SARS-CoV-2 patients exhibit high levels of ACE2 and Ang-(1-7). This phenomenon could indicate a failing physiological response to prevent or reduce the severity of inflammation-mediated pulmonary injuries. Alamandine, which is another protective component of the RAS, has several health benefits owing to its antithrombogenic, anti-inflammatory, and antifibrotic characteristics. Alamandine alleviates pulmonary fibrosis via the Mas-related G protein-coupled receptor D (MrgD). Thus, a better understanding of this pathway could uncover novel pharmacological strategies for altering proinflammatory environments within the body. Following such strategies could inhibit fibrosis after SARS-CoV-2 infection and, consequently, prevent COVID-19.

Alamandine, a derivative of angiotensin-(1-7), alleviates sepsis-associated renal inflammation and apoptosis by inhibiting the PI3K/Ak and MAPK pathways

Sepsis is a frequent cause of kidney injury. The present study investigated whether Alamandine (Ala) could alleviate sepsis-associated renal injury by reducing inflammation and apoptosis. In addition, we investigated downstream signaling pathways modulated by Ala. Studies were performed in mice treated with lipopolysaccharide (LPS) and in the human proximal tubular epithelial cell line HK-2. The increase in serum creatinine, blood urea nitrogen, cystatin C and Fg, and neutrophil gelatinase-associated lipocalin and kidney injury molecule-1 in the kidneys of mice treated with LPS were reduced after administration of Ala. Exposure to LPS increased interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) in mice and HK-2 cells, but were reduced after Ala treatment. Furthermore, increased levels of cleaved caspase 3, cleaved caspase 7, cleaved caspase 9, cleaved poly (ADP-ribose) polymerase (PARP) and Bax and reduced levels of Bcl2 in LPS-treated mice and HK-2 cells were reversed after Ala administration. In addition, LPS increased the levels of p-PI3K/PI3K, p-Akt/Akt, p-ERK/ERK, p-JNK/JNK, p-p38/p38 and p-FoxO1 in HK-2 cells, and all were reversed after Ala administration. These results indicate that Ala could improve renal function and inhibit inflammation and apoptosis in LPS induced sepsis mouse models. We demonstrated that Ala attenuated LPS induced sepsis by inhibiting the PI3K/Akt and MAPK signaling pathways.

Irisin Protects Against LPS-Stressed Cardiac Damage Through Inhibiting Inflammation, Apoptosis, and Pyroptosis

ABSTRACT

Septic cardiac dysfunction remains a clinical problem due to its high morbidity and mortality. Uncontrolled cell death and excessive inflammatory response are closely related to sepsis-induced cardiac dysfunction. Irisin has been found to play cardioprotective roles in sepsis. However, there is enough uncertainty in the mechanism of irisin-mediated cardioprotection. We hypothesized that irisin may ameliorate myocardial dysfunction via reducing cardiac apoptosis, pyroptosis, and inflammation during LPS-induced sepsis. Mice were subjected to LPS with or without irisin treatment. After stimuli of LPS, the function of myocardium was distinctly impaired, which was closely related to increased level of apoptosis (decreased expression of Bcl-2 and elevated expression of Caspase-3 and Bax), pyroptosis (increased expression of Caspase1, NLR family pyrin domain containing 3 (NLRP3), and gasdermin D) and inflammatory mediators (increased level of IL-1β, TNF-α, and IL-6). This process is consistent with increased toll-like receptor 4 (TLR4)/nuclear factor-kappa B signal, apoptotic signal, and NLRP3-mediated pyroptotic signal. Activation of apoptosis and pyroptosis enhanced the expression of proinflammatory cytokines and further exacerbated septic myocardial damage. However, irisin can inhibit the expression of TLR4 and its downstream signaling molecules and also lower the level of apoptosis and pyroptosis. Besides, similar results were also found in vitro model of LPS-induced H9c2 cardiomyocyte injury. In general, irisin suppressed inflammation, apoptosis, and pyroptosis by blocking the TLR4 and NLRP3 inflammasome signalings to mitigate myocardial dysfunction in sepsis.

CXCR5 down-regulation alleviates cognitive dysfunction in a mouse model of sepsis-associated encephalopathy: potential role of microglial autophagy and the p38MAPK/NF-κB/STAT3 signaling pathway

Background

Cognitive deficits are common in patients with sepsis. Previous studies in sepsis-associated encephalopathy (SAE) implicated the C-X-C chemokine receptor type (CXCR) 5. The present study used a mouse model of SAE to examine whether CXCR5 down-regulation could attenuate cognitive deficits.

Methods

Sepsis was induced in adult male C57BL/6 J and CXCR5^−/− mice by cecal ligation and puncture (CLP). At 14–18 days after surgery, animals were tested in a Morris water maze, followed by a fear conditioning test. Transmission electron microscopy of hippocampal sections was used to assess levels of autophagy. Primary microglial cultures challenged with lipopolysaccharide (LPS) were used to examine the effects of short interfering RNA targeting CXCR5, and to investigate the possible involvement of the p38MAPK/NF-κB/STAT3 signaling pathway.

Results

CLP impaired learning and memory and up-regulated CXCR5 in hippocampal microglia. CLP activated hippocampal autophagy, as reflected by increases in numbers of autophagic vacuoles, conversion of microtubule-associated protein 1 light chain 3 (LC3) from form I to form II, accumulation of beclin-1 and autophagy-related gene-5, and a decrease in p62 expression. CLP also shifted microglial polarization to the M1 phenotype, and increased levels of IL-1β, IL-6 and phosphorylated p38MAPK. CXCR5 knockout further enhanced autophagy but partially reversed all the other CLP-induced effects, including cognitive deficits. Similar effects on autophagy and cytokine expression were observed after knocking down CXCR5 in LPS-challenged primary microglial cultures; this knockdown also partially reversed LPS-induced up-regulation of phosphorylated NF-κB and STAT3. The p38MAPK agonist P79350 partially reversed the effects of CXCR5 knockdown in microglial cultures.

Conclusions

CXCR5 may act via p38MAPK/NF-κB/STAT3 signaling to inhibit hippocampal autophagy during sepsis and thereby contribute to cognitive dysfunction. Down-regulating CXCR5 can restore autophagy and mitigate the proinflammatory microenvironment in the hippocampus.

Alamandine protects against renal ischaemia-reperfusion injury in rats via inhibiting oxidative stress

OBJECTIVE

This study was to determine whether alamandine (Ala) could reduce ischaemia and reperfusion (I/R) injury of kidney in rats.

METHODS

Renal I/R was induced by an occlusion of bilateral renal arteries for 70 min and a 24-h reperfusion in vivo, and rat kidney proximal tubular epithelial cells NRK52E were exposed to 24 h of hypoxia and followed by 3-h reoxygenation (H/R) in vitro.

RESULTS

The elevated serum creatinine (Cr), blood cystatin C (CysC) and blood urea nitrogen (BUN) levels in I/R rats were inhibited by Ala treatment. Tumour necrosis factor alpha (TNF)-α, IL-1β, IL-6, cleaved caspase-3, cleaved caspase-8 and Bax were increased, and Bcl2 was reduced in the kidney of I/R rats, which were reversed by Ala administration. Ala reversed the increase of TNF-α, IL-1β, IL-6, cleaved caspase-3, cleaved caspase-8 and Bax and the decrease of Bcl2 in the H/R NRK52E cells. Ala could also inhibit the increase of oxidative stress levels in the kidney of I/R rats. NADPH oxidase 1 (Nox1) overexpression reversed the improving effects of Ala on renal function, inflammation and apoptosis of I/R rats.

CONCLUSION

These results indicated that Ala could improve renal function, attenuate inflammation and apoptosis in the kidney of I/R rats via inhibiting oxidative stress.

LncRNA PVT1 Knockdown Ameliorates Myocardial Ischemia Reperfusion Damage via Suppressing Gasdermin D-Mediated Pyroptosis in Cardiomyocytes

Objective: Myocardial ischemia reperfusion (I/R) damage is a life-threatening vascular emergency after myocardial infarction. Here, we observed the cardioprotective effect of long non-coding RNA (lncRNA) PVT1 knockdown against myocardial I/R damage.

Methods: This study constructed a myocardial I/R-induced mouse model and a hypoxia/reoxygenation (H/R)-treated H9C2 cells. PVT1 expression was examined via RT-qPCR. After silencing PVT1 via shRNA against PVT1, H&E, and Masson staining was performed to observe myocardial I/R damage. Indicators of myocardial injury including cTnI, LDH, BNP, and CK-MB were examined by ELISA. Inflammatory factors (TNF-α, IL-1β, and IL-6), Gasdermin D (GSDMD), and Caspase1 were detected via RT-qPCR, western blot, immunohistochemistry, or immunofluorescence. Furthermore, CCK-8 and flow cytometry were presented for detecting cell viability and apoptosis.

Results: LncRNA PVT1 was markedly up-regulated in myocardial I/R tissue specimens as well as H/R-induced H9C2 cells. Silencing PVT1 significantly lowered serum levels of cTnI, LDH, BNP, and CK-MB in myocardial I/R mice. H&E and Masson staining showed that silencing PVT1 alleviated myocardial I/R injury. PVT1 knockdown significantly lowered the production and release of inflammatory factors as well as inhibited the expression of GSDMD-N and Caspase1 in myocardial I/R tissue specimens as well as H/R-induced H9C2 cells. Moreover, silencing PVT1 facilitated cell viability and induced apoptosis of H/R-treated H9C2 cells.

Conclusion: Our findings demonstrated that silencing PVT1 could alleviate myocardial I/R damage through suppressing GSDMD-mediated pyroptosis in vivo and in vitro. Thus, PVT1 knockdown may offer an alternative therapeutic strategy against myocardial I/R damage.

Angiotensin-(1-7) protects against sepsis-associated left ventricular dysfunction induced by lipopolysaccharide

Sepsis-induced myocardial dysfunction is a major cause of death. The present study explored whether angiotensin (Ang)-(1-7), an important biologically active peptide of the renin-angiotensin system, could improve cardiac dysfunction and attenuate inflammation and apoptosis. Experiments were carried out in mice and in neonatal rat cardiomyocytes (NRCMs) treated with lipopolysaccharide (LPS) or Ang-(1-7). Angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and Mas receptor (MasR) expressions were reduced in the mouse left ventricular and NRCM treated with LPS. Ang-(1-7) increased the ejection fraction and fractional shortening of left ventricular, which were reduced upon LPS injection in mice. Ang-(1-7) pre-treatment reversed LPS-induced decreases of α-myosin heavy chain (MHC) and β-MHC, and increases of S100 calcium binding protein A8 (S100A8) and S100A9 in the mouse left ventricular. The LPS-induced increases of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the mouse left ventricular and NRCMs were inhibited by Ang-(1-7) administration. Ang-(1-7) treatment reversed the increases of cleaved-caspase 3, cleaved-caspase 8 and Bax, and the decrease of Bcl2 induced by LPS in the mouse left ventricular and NRCMs. The increases of MAPKs pathway induced by LPS in NRCMs were inhibited by Ang-(1-7). These results indicate that Ang-(1-7) protects against sepsis-associated left ventricular dysfunction induced by LPS, and increases cardiac contractility via attenuating inflammation and apoptosis.

Selective inhibition of PKCβ2 improves Caveolin-3/eNOS signaling and attenuates lipopolysaccharide-induced injury by inhibiting autophagy in H9C2 cardiomyocytes

Lipopolysaccharide (LPS)-induced autophagy is involved in sepsis-associated myocardial injury with increased PKCβ2 activation. We previously found hyperglycemia-induced PKCβ2 activation impaired the expression of caveolin-3 (Cav-3), the dominant isoform to form cardiomyocytes caveolae which modulate eNOS signaling to confer cardioprotection in diabetes. However, little is known about the roles of PKCβ2 in autophagy and Cav-3/eNOS signaling in cardiomyocytes during LPS exposure. We hypothesize LPS-induced PKCβ2 activation promotes autophagy and impairs Cav-3/eNOS signaling in LPS-treated cardiomyocytes. H9C2 cardiomyocytes were treated with LPS (10 µg/mL) in the presence or absence of PKCβ2 inhibitor CGP53353 (CGP, 1 µM) or autophagy inhibitor 3-methyladenine (3-MA, 10 µM). LPS stimulation induced cytotoxicity overtime in H9C2 cardiomyocytes, accompanied with excessive PKCβ2 activation. Selective inhibition of PKCβ2 with CGP significantly reduced LPS-induced cytotoxicity and autophagy (measured by LC-3II, Beclin-1, p62 and autophagic flux). In addition, CGP significantly attenuated LPS-induced oxidative injury, and improved Cav-3 expression and eNOS activation, similar effects were shown by the treatment of autophagy inhibitor 3-MA. LPS-induced myocardial injury is associated with excessive PKCβ2 activation, which contributes to elevated autophagy and impaired Cav-3/eNOS signaling. Selective inhibition of PKCβ2 improves Cav-3/eNOS signaling and attenuates LPS-induced injury through inhibiting autophagy in H9C2 cardiomyocytes.

CD38 deficiency up-regulated IL-1β and MCP-1 through TLR4/ERK/NF-κB pathway in sepsis pulmonary injury

As a disease with high mortality,many cytokines and signaling pathways are associated with sepsis.The pro-inflammatory cytokines and chemokines are participating in the pathogenesis of sepsis, especially in early stage. Moreover, the releases and expressions of cytokines are regulated by numerous signaling pathways, including TLR4/ERK pathway. But despite many studies have expounded the pathogenesis of sepsis and the regulation of cytokines in sepsis, how CD38 influence the expressions of related molecules in sepsis are still unknown. The aim of this study is illuminating the alteration of cytokines and signaling pathways in CD38^-/- mice injected with Escherichia coli.Compared with WT mice, E. coli infection results in more severe pulmonary injuries and higher mRNA expressions of cytokines. Compared with E. coli infected WT mice,CD38 knockout leads to aggravated pulmonary injury, increasedphosphorylated ERK1/2, p38 and NF-κB p65, and enhancedlevels of IL-1β, iNOS and MCP-1.While compared with E. coli infected CD38^-/- mice, TLR4 mutation results in alleviated pulmonary injury, down-regulated phosphorylated ERK1/2 and NF-κB p65, and decreased expressions of IL-1β and MCP-1.CD38 deficiency increased the expressions of IL-1β andMCP-1and aggravated pulmonary injury through TLR4/ERK/NF-κB pathway in sepsis.

Deficiency of Endothelial Nitric Oxide Synthase (eNOS) Exacerbates Brain Damage and Cognitive Deficit in A Mouse Model of Vascular Dementia

Vascular Dementia (VaD) accounts for nearly 20% of all cases of dementia. eNOS plays an important role in neurovascular remodeling, anti-inflammation, and cognitive functional recovery after stroke. In this study, we investigated whether eNOS regulates brain damage, cognitive function in mouse model of bilateral common carotid artery stenosis (BCAS) induced VaD. Late-adult (6-8 months) C57BL/6J and eNOS knockout (eNOS-/-) mice were subjected to BCAS (n=12/group) or sham group (n=8/group). BCAS was performed by applying microcoils to both common carotid arteries. Cerebral blood flow (CBF) and blood pressure were measured. A battery of cognitive functional tests was performed, and mice were sacrificed 30 days after BCAS. Compared to corresponding sham mice, BCAS in wild-type (WT) and eNOS-/- mice significantly: 1) induces short term, long term memory loss, spatial learning and memory deficits; 2) decreases CBF, increases ischemic cell damage, including apoptosis, white matter (WM) and axonal damage; 3) increases blood brain barrier (BBB) leakage, decreases aquaporin-4 (AQP4) expression and vessel density; 4) increases microglial, astrocyte activation and oxidative stress in the brain; 5) increases inflammatory factor interleukin-1 receptor-associated kinase-1(IRAK-1) and amyloid beta (Aβ) expression in brain; 6) increases IL-6 and IRAK4 expression in brain. eNOS-/-sham mice exhibit increased blood pressure, decreased iNOS and nNOS in brain compared to WT-sham mice. Compared to WT-BCAS mice, eNOS-/-BCAS mice exhibit worse vascular and WM/axonal damage, increased BBB leakage and inflammatory response, increased cognitive deficit, decreased iNOS, nNOS in brain. eNOS deficit exacerbates BCAS induced brain damage and cognitive deficit.

Protective effect of alamandine on doxorubicin‑induced nephrotoxicity in rats

BACKGROUND

This study aimed to evaluate the protective effects of alamandine, a new member of the angiotensin family, against doxorubicin (DOX)-induced nephrotoxicity in rats.

METHODS

Rats were intraperitoneally injected with DOX (3.750 mg/kg/week) to reach a total cumulative dose of 15 mg/kg by day 35. Alamandine (50 µg/kg/day) was administered to the rats via mini-osmotic pumps for 42 days. At the end of the experiment, rats were placed in the metabolic cages for 24 h so that their water intake and urine output could be measured. After scarification, the rats' serum and kidney tissues were collected, and biochemical, histopathological, and immunohistochemical studies were carried out.

RESULTS

DOX administration yielded increases in pro-inflammatory cytokines, including interleukin (IL)-1β and IL-6, pro-fibrotic proteins transforming growth factor-β (TGF-β), pro-inflammatory transcription factor nuclear kappa B (NF-κB), kidney malondialdehyde (MDA), creatinine clearance, blood urea nitrogen (BUN), and water intake. On the other hand, the DOX-treated group exhibited decreased renal superoxide dismutase (SOD), renal glutathione peroxidase (GPx) activity, and urinary output. Alamandine co-therapy decreased these effects, as confirmed by histopathology and immunohistochemical analysis.

CONCLUSIONS

The results suggest that alamandine can prevent nephrotoxicity induced by DOX‎ in rats.

Nitric Oxide Alleviated High Salt-Induced Cardiomyocyte Apoptosis and Autophagy Independent of Blood Pressure in Rats

The present study aimed to explore whether high-salt diet (HSD) could cause cardiac damage independent of blood pressure, and whether nitric oxide (NO) could alleviate high-salt-induced cardiomyocyte apoptosis and autophagy in rats. The rats received 8% HSD in vivo. H9C2 cells or primary neonatal rat cardiomyocytes (NRCM) were treated with sodium chloride (NaCl) in vitro. The levels of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2, LC3 II/LC3 I, Beclin-1 and autophagy related 7 (ATG7) were increased in the heart of HSD rats with hypertension (HTN), and in hypertension-prone (HP) and hypertension-resistant (HR) rats. Middle and high doses (50 and 100 mM) of NaCl increased the level of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2, LC3 II/LC3 I, Beclin-1, and ATG7 in H9C2 cells and NRCM. The endothelial NO synthase (eNOS) level was increased, but p-eNOS level was reduced in the heart of HSD rats and H9C2 cells treated with 100 mM NaCl. The level of NO was reduced in the serum and heart of HSD rats. NO donor sodium nitroprusside (SNP) reversed the increases of cleaved-caspase 3/caspase 3, cleaved-caspase 8/caspase 8, Bax/Bcl2 induced by NaCl (100 mM) in H9C2 cells and NRCM. SNP treatment attenuated the increases of cleaved-caspase 3/caspase 3, Bax/Bcl2, LC3 II/LC3 I, Beclin-1, and ATG7 in the heart, but had no effect on the blood pressure of HSD rats with HR. These results demonstrated that HSD enhanced cardiac damage independently of blood pressure. Exogenous NO supplementarity could alleviate the high salt-induced apoptosis and autophagy in cardiomyocytes.

Alamandine significantly reduces doxorubicin-induced cardiotoxicity in rats

Doxorubicin (DOX) is an anthracycline antibiotic. Despite its unwanted side effects, it has been successfully used in tumor therapy. Given that oxidative stress and inflammatory factors are essential to cardiotoxicity caused by DOX, we assumed that alamandine, which enhances endogenous antioxidants and has anti-inflammatory effects, may prevent DOX-induced cardiotoxicity. Rats received DOX (3.75 mg/kg) i.p on days 14, 21, 28, and 35 (total cumulative dose = 15 mg/kg) and alamandine (50 μg/kg/day) via mini-osmotic pumps for 42 days. At the end of the 42-day period, we evaluated hemodynamic parameters, electrocardiogram, cardiac troponin I (cTnI), superoxidase dismutase (SOD), total antioxidant capacity (TAC), malondialdehyde (MDA), inflammatory cytokines (tumor necrosis factor-α (TNF-α), IL-1β, NF-κB), apoptosis markers (caspase 3), and histopathology of haemotoxylin- and eosin-stained cardiac muscle fibers were evaluated. DOX significantly increased QT, corrected QT (QTc), and RR intervals. Alamandine co-therapy prevented ECG changes. Alamandine administration restored DOX-induced disruptions in the cardiac muscle architecture and vascular congestion. Alamandine co-therapy also alleviated other effects of DOX, including cardiac contractility, decreased systolic and diastolic blood pressure, and increased left ventricular end-diastolic pressure. Moreover, alamandine co-therapy substantially decreased the elevation of oxidative stress markers, inflammatory cytokines, and caspase 3 in DOX-treated rats. The results suggest that alamandine reduced DOX-induced cardiotoxicity via antioxidant, anti-inflammatory, and anti-apoptotic activities.

Targeting the Protective Arm of the Renin-Angiotensin System: Focused on Angiotensin-(1-7)

The in vivo application and efficacy of many therapeutic peptides is limited because of their instability and proteolytic degradation. Novel strategies for developing therapeutic peptides with higher stability toward proteolytic degradation would be extremely valuable. Such approaches could improve systemic bioavailability and enhance therapeutic effects. The renin-angiotensin system (RAS) is a hormonal system within the body essential for the regulation of blood pressure and fluid balance. The RAS is composed of two opposing classic and protective arms. The balance between these two arms is critical for the homeostasis of the body's physiologic function. Activation of the RAS results in the suppression of its protective arm, which has been reported in inflammatory and pathologic conditions such as arthritis, cardiovascular diseases, diabetes, and cancer. Clinical application of angiotensin-(1-7) [Ang-(1-7)], a RAS critical regulatory peptide, augments the protective arm and restores balance hampered by its enzymatic and chemical instability. Several attempts to increase the half-life and efficacy of this heptapeptide using more stable analogs and different drug delivery approaches have been made. This review article provides an overview of efforts targeting the RAS protective arm. It provides a critical analysis of Ang-(1-7) or its homologs' novel drug delivery systems using different administration routes, their pharmacological characterization, and therapeutic potential in various clinical settings. SIGNIFICANCE STATEMENT: Ang-(1-7) is a unique peptide component of the renin-angiotensin system with vast potential for clinical applications that modulate various inflammatory diseases. Novel Ang-(1-7) peptide drug delivery could compensate its lack of stability for effective clinical application.

Regulatory role of the TLR4/JNK signaling pathway in sepsis‑induced myocardial dysfunction

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, and is a leading cause of mortality worldwide. Myocardial dysfunction is associated with poor prognosis in patients with sepsis and contributes to a high risk of mortality. However, the pathophysiological mechanisms underlying sepsis-induced myocardial dysfunction are not completely understood. The aim of the present study was to investigate the role of toll-like receptor 4 (TLR4)/c-Jun N-terminal kinase (JNK) signaling in pro-inflammatory cytokine expression and cardiac dysfunction during lipopolysaccharide (LPS)-induced sepsis in mice. C57BL/6 mice were pretreated with TAK-242 or saline for 1 h and then subjected to LPS (12 mg/kg, intraperitoneal) treatment. Cardiac function was assessed using an echocardiogram. The morphological changes of the myocardium were examined by hematoxylin and eosin staining and transmission electron microscopy. The serum protein levels of cardiac troponin I (cTnI) and tumor necrosis factor-α (TNF-α) were determined by an enzyme-linked immunosorbent assay (ELISA). The TLR4 and JNK mRNA levels were analyzed via reverse transcription-quantitative PCR. TLR4, JNK and phosphorylated-JNK protein levels were measured by western blotting. In response to LPS, the activation of TLR4 and JNK in the myocardium was upregulated. There were significant increases in the serum levels of TNF-α and cTnI, as well as histopathological changes in the myocardium and suppressed cardiac function, following LPS stimulation. Inhibition of TLR4 activation using TAK-242 led to a decrease in the activation of JNK and reduced the protein expression of TNF-α in plasma, and alleviated histological myocardial injury and improved cardiac function during sepsis in mice. The present data suggested that the TLR4/JNK signaling pathway played a critical role in regulating the production of pro-inflammatory cytokines and myocardial dysfunction induced by LPS.

Therapeutic approaches targeting renin-angiotensin system in sepsis and its complications

Sepsis, caused by the inappropriate host response to infection, is characterized by excessive inflammatory response and organ dysfunction, thus becomes a critical clinical problem. Commonly, sepsis may progress to septic shock and severe complications, including acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), sepsis-induced myocardial dysfunction (SIMD), liver dysfunction, cerebral dysfunction, and skeletal muscle atrophy, which predominantly contribute to high mortality. Additionally, the global pandemic of coronavirus disease 2019 (COVID-19) raised the concern of development of effectve therapeutic strategies for viral sepsis. Renin-angiotensin system (RAS) may represent as a potent therapeutic target for sepsis therapy. The emerging role of RAS in the pathogenesis of sepsis has been investigated and several preclinical and clinical trials targeting RAS for sepsis treatment revealed promising outcomes. Herein, we attempt to review the effects and mechanisms of RAS manipulation on sepsis and its complications and provide new insights into optimizing RAS interventions for sepsis treatment.

Inhibition of miR‑101‑3p protects against sepsis‑induced myocardial injury by inhibiting MAPK and NF‑κB pathway activation via the upregulation of DUSP1

Numerous studies have found that microRNAs (miRNAs or miRs) are aberrantly expressed when sepsis occurs. The present study aimed to investigate the role of miR-101-3p in sepsis-induced myocardial injury and to elucidate the underlying mechanisms. Models of myocardial injury were established both in vivo and in vitro. The results revealed that miR-101-3p was upregulated in the serum of patients with sepsis-induced cardiomyopathy (SIC) and positively correlated with the levels of pro-inflammatory cytokines (including IL-1β, IL-6 and TNF-α). Subsequently, rats were treated with miR-101-3p inhibitor to suppress miR-101-3p and were then exposed to lipopolysaccharide (LPS). The results revealed that LPS induced marked cardiac dysfunction, apoptosis and inflammation. The inhibition of miR-101-3p markedly attenuated sepsis-induced myocardial injury by attenuating apoptosis and the expression of pro-inflammatory cytokines. Mechanistically, dual specificity phosphatase-1 (DUSP1) was found to be a functional target of miR-101-3p. The downregulation of miR-101-3p led to the overexpression of DUSP1, and the inactivation of the MAPK p38 and NF-κB pathways. Moreover, blocking DUSP1 by short hairpin RNA against DUSP1 (sh-DUSP1) significantly reduced the myocardial protective effects mediated by the inhibition of miR-101-3p. Collectively, the findings of the present study demonstrate that the inhibition of miR-101-3p exerts cardioprotective effects by suppressing MAPK p38 and NF-κB pathway activation, and thus attenuating inflammation and apoptosis dependently by enhancing DUSP1 expression.

Alamandine improves cardiac remodeling induced by transverse aortic constriction in mice

Alamandine is the newest identified peptide of the renin-angiotensin system (RAS) and has protective effects in the cardiovascular system. Although the involvement of classical RAS components in the genesis and progression of cardiac remodeling is well known, less is known about the effects of alamandine. Therefore, in the present study we investigated the effects of alamandine on cardiac remodeling induced by transverse aortic constriction (TAC) in mice. Male mice (C57BL/6), 10-12 wk of age, were divided into three groups: sham operated, TAC, and TAC + ALA (30 µg/kg/day alamandine for 14 days). The TAC surgery was performed under ketamine and xylazine anesthesia. At the end of treatment, the animals were submitted to echocardiographic examination and subsequently euthanized for tissue collection. TAC induced myocyte hypertrophy, collagen deposition, and the expression of matrix metalloproteinase (MMP)-2 and transforming growth factor (TGF)-β in the left ventricle. These markers of cardiac remodeling were reduced by oral treatment with alamandine. Western blotting analysis showed that alamandine prevents the increase in ERK1/2 phosphorylation and reverts the decrease in 5'-adenosine monophosphate-activated protein kinase (AMPK)α phosphorylation induced by TAC. Although both TAC and TAC + ALA increased SERCA2 expression, the phosphorylation of phospholamban in the Thr17 residue was increased solely in the alamandine-treated group. The echocardiographic data showed that there are no functional or morphological alterations after 2 wk of TAC. Alamandine treatment prevents myocyte hypertrophy and cardiac fibrosis induced by TAC. Our results reinforce the cardioprotective role of alamandine and highlight its therapeutic potential for treating heart diseases related to pressure overload conditions.NEW & NOTEWORTHY Alamandine is the newest identified component of the renin-angiotensin system protective arm. Considering the beneficial effects already described so far, alamandine is a promising target for cardiovascular disease treatment. We demonstrated for the first time that alamandine improves many aspects of cardiac remodeling induced by pressure overload, including cell hypertrophy, fibrosis, and oxidative stress markers.

Renin-Angiotensin System: An Important Player in the Pathogenesis of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is characterized by massive inflammation, increased vascular permeability and pulmonary edema. Mortality due to ARDS remains very high and even in the case of survival, acute lung injury can lead to pulmonary fibrosis. The renin-angiotensin system (RAS) plays a significant role in these processes. The activities of RAS molecules are subject to dynamic changes in response to an injury. Initially, increased levels of angiotensin (Ang) II and des-Arg⁹-bradykinin (DABK), are necessary for an effective defense. Later, augmented angiotensin converting enzyme (ACE) 2 activity supposedly helps to attenuate inflammation. Appropriate ACE2 activity might be decisive in preventing immune-induced damage and ensuring tissue repair. ACE2 has been identified as a common target for different pathogens. Some Coronaviruses, including SARS-CoV-2, also use ACE2 to infiltrate the cells. A number of questions remain unresolved. The importance of ACE2 shedding, associated with the release of soluble ACE2 and ADAM17-mediated activation of tumor necrosis factor-α (TNF-α)-signaling is unclear. The roles of other non-classical RAS-associated molecules, e.g., alamandine, Ang A or Ang 1-9, also deserve attention. In addition, the impact of established RAS-inhibiting drugs on the pulmonary RAS is to be elucidated. The unfavorable prognosis of ARDS and the lack of effective treatment urge the search for novel therapeutic strategies. In the context of the ongoing SARS-CoV-2 pandemic and considering the involvement of humoral disbalance in the pathogenesis of ARDS, targeting the renin-angiotensin system and reducing the pathogen's cell entry could be a promising therapeutic strategy in the struggle against COVID-19.

A novel biscoumarin derivative dephosphorylates ERK and alleviates apoptosis induced by mitochondrial oxidative damage in ischemic stroke mice

AIM

We previously reported the protective effects of biscoumarin derivatives against oxidative stress, but effects of the derivative on mitochondrial oxidative damage induced apoptosis in ischemic stroke remains unknown.

METHODS

Primary neurons were subjected to oxygen and glucose deprivation (OGD) for the in vitro simulation of ischemic stroke, and an ischemic stroke model was established in mice by operation of middle cerebral artery occlusion (MCAO).

RESULTS

The results indicated that the nontoxic concentration range of biscoumarin derivative Comp. B in neurons was from 0 to 30 μg/ml and the optimal protective concentration was 20 μg/ml. Treatment with Comp. B increased the cell survival rate and alleviated mitochondrial oxidative damage and apoptosis in OGD-treated neurons. Comp. B reduced the ratio of Bax/Bcl-2, inhibited the phosphorylation of ERK, and thus alleviated apoptosis in OGD-treated neurons. Further research demonstrated that the dephosphorylation effect on ERK of Comp. B is a key factor in alleviating apoptosis in neurons induced by OGD injury. Furthermore, Comp. B reduced the infarct volume, improved neurobehavioural score, and alleviated morphological changes and brain apoptosis in MCAO mice.

CONCLUSION

The novel biscoumarin derivative Comp. B alleviates mitochondrial oxidative damage and apoptosis in ischemic stroke mice. These findings might provide new insights that will aid in elucidating the effect of biscoumarin derivative against cerebral ischemic reperfusion injury and support the new development of Comp. B as a potential treatment for ischemic stroke.

S100A9 Upregulation Contributes to Learning and Memory Impairments by Promoting Microglia M1 Polarization in Sepsis Survivor Mice

Sepsis-associated encephalopathy (SAE) is a clinical syndrome of brain dysfunction secondary to sepsis, which is characterized by long-term neurocognitive deficits such as memory, attention, and executive dysfunction. However, the mechanisms underlying SAE remain unclear. By using transcriptome sequencing approach, we showed that hippocampal S100A9 was significantly increased in sepsis induced by cecal ligation and puncture (CLP) or lipopolysaccharide (LPS) challenge. Thus, we used S100A9 inhibitor Paquinimod to study the role of S100A9 in cognitive impairments in CLP-induced and LPS-induced mice models of SAE. Sepsis survivor mice underwent behavioral tests or the hippocampal tissues subjected to Western blotting, real-time quantitative PCR, and immunohistochemistry. Our results showed that CLP-induced and LPS-induced memory impairments were accompanied with increased expressions of hippocampal microglia Iba1 and CD86 (M1 markers), but reduced expression of Arg1 (M2 marker). Notably, S100A9 inhibition significantly improved the survival rate and learning and memory impairments in sepsis survivors, with a shift from M1 to M2 phenotype. Taken together, our study suggests that S100A9 upregulation might contribute to learning and memory impairments by promoting microglia M1 polarization in sepsis survivors, whereas S100A9 inhibition might provide a potential therapeutic target for SAE.

Oleuropein protects against lipopolysaccharide-induced sepsis and alleviates inflammatory responses in mice

Sepsis results from a major systemic inflammatory response and can induce disorders in multiple organs. The present study evaluated the potential protective effects of oleuropein (OLE) against hyperinflammatory responses during lipopolysaccharide (LPS)-induced sepsis in mice. Sixty male Balb/c mice were randomly categorized into five groups of 12 animals each: control, intraperitoneally injected with OLE (50 mg/kg), injected with LPS (10 mg/kg, intraperitoneal), and two groups administered OLE (25 and 50 mg/kg) for 3 days prior to LPS injection. Twenty-four hours after lipopolysaccharide injection, the animals were sacrificed. Serum, liver, and kidney tissue samples were collected for biochemical analyses, histopathological examinations, and investigation of inflammation-related gene expression. OLE pretreatment significantly reduced liver damage parameters (alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase) and kidney damage parameters (blood urea nitrogen, creatinine, and kidney injury molecule-1) in the septic mice. OLE pretreatment ameliorated LPS-induced liver and kidney histological changes. OLE significantly mitigated the increased levels of malondialdehyde in the liver and kidneys and reduced levels of reduced glutathione induced by LPS. LPS injection also resulted in increased expression of the proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and inflammation-related genes (Nos2, Hmgb1, Mpo, Cd46, Map2k4, and Map2k7) in the hepatic and renal tissues. OLE reduced these expressions to ameliorate the inflammatory response. Moreover, OLE pretreatment enhanced the survival rate of septic mice. In conclusion, OLE alleviated the inflammatory response to protect against LPS-induced sepsis in mice.

Alamandine attenuates angiotensin II-induced vascular fibrosis via inhibiting p38 MAPK pathway

Alamandine attenuates hypertension and cardiac remodeling in spontaneously hypertensive rats (SHRs). We examined whether alamandine attenuates vascular remodeling in mice, and regulates angiotensin II (Ang II)-induced fibrosis in rat vascular smooth muscle cells (VSMCs). Alamandine attenuated hypertension in mice induced by Ang II. Ang II increased the fibrosis of thoracic aorta in mice, which was attenuated by alamandine treatment. Increased levels of collagen I, transforming growth factor-β (TGF-β), and connective tissue growth factor (CTGF) levels in thoracic aortas after Ang II treatment in mice were inhibited by alamandine. Ang II-stimulated collagen I, TGF-β, and CTGF level increases were inhibited by alamandine in rat VSMCs. This could be reversed by Mas-related G protein-coupled receptor, member D (MrgD) antagonist D-Pro⁷-Ang-(1-7) but not Mas receptor antagonist A779. MrgD expression was increased in the thoracic aortas of mice or VSMCs treatment with Ang II. Ang II increased p-p38 and cAMP levels in rat VSMCs, and alamandine blocked Ang II-induced these increases. Cyclic adenosine monophosphate (cAMP) reversed the inhibitory effects of alamandine on the Ang II-induced increases in collagen I, TGF-β, and CTGF levels. These results demonstrate alamandine attenuates vascular fibrosis by stimulating MrgD expression and decreases arterial fibrosis by blocking p-p38 expression. Alamandine/MrgD axis is a potential target for the treatment of vascular remodeling.

Alamandine attenuates hepatic fibrosis by regulating autophagy induced by NOX4-dependent ROS

Angiotensin II (Ang II) has been reported to aggravate hepatic fibrosis by inducing NADPH oxidase (NOX)-dependent oxidative stress. Alamandine (ALA) protects against fibrosis by counteracting Ang II via the MAS-related G-protein coupled (MrgD) receptor, though the effects of alamandine on hepatic fibrosis remain unknown. Autophagy activated by reactive oxygen species (ROS) is a novel mechanism of hepatic fibrosis. However, whether autophagy is involved in the regulation of Ang II-induced hepatic fibrosis still requires investigation. We explored the effect of alamandine on hepatic fibrosis via regulation of autophagy by redox balance modulation. In vivo, alamandine reduced CCl4-induced hepatic fibrosis, hydrogen peroxide (H2O2) content, protein levels of NOX4 and autophagy impairment. In vitro, Ang II treatment elevated NOX4 protein expression and ROS production along with up-regulation of the angiotensin converting enzyme (ACE)/Ang II/Ang II type 1 receptor (AT1R) axis. These changes resulted in the accumulation of impaired autophagosomes in hepatic stellate cells (HSCs). Treatment with NOX4 inhibitor VAS2870, ROS scavenger N-acetylcysteine (NAC), and NOX4 small interfering RNA (siRNA) inhibited Ang II-induced autophagy and collagen synthesis. Alamandine shifted the balance of renin-angiotensin system (RAS) toward the angiotensin converting enzyme 2 (ACE2)/alamandine/MrgD axis, and inhibited both Ang II-induced ROS and autophagy activation, leading to attenuation of HSCs migration or collagen synthesis. In summary, alamandine attenuated liver fibrosis by regulating autophagy induced by NOX4-dependent ROS.

miR-214-3p Attenuates Sepsis-Induced Myocardial Dysfunction in Mice by Inhibiting Autophagy through PTEN/AKT/mTOR Pathway

Aims. More than half of the patients with sepsis would develop cardiac dysfunction, which is termed as sepsis-induced myocardial dysfunction (SIMD). Previous studies suggest that autophagy may play an important role in SIMD. The present study investigated whether miR-214-3p could attenuate SIMD by inhibiting autophagy. Main Methods. In this article, we investigated the role of autophagy in a mouse model of cecal ligation and puncture (CLP). The structure and function of hearts harvested from the mice were evaluated. Myocardial autophagy levels were detected with immunohistochemical, immunofluorescent, and Western blot. Key Findings. miR-214-3p can alleviate SIMD in septic mice by inhibiting the level of cardiac autophagy to attenuate myocardial dysfunction. Moreover, this study showed that miR-214-3p inhibited autophagy by silencing PTEN expression in the myocardial tissues of septic mice. Significance. This study showed that miR-214-3p attenuated SIMD through myocardial autophagy inhibition by silencing PTEN expression and activating the AKT/mTOR pathway. The present findings supported that miR-214-3p may be a potential therapeutic target for SIMD.

The Network of Angiotensin Receptors in Breast Cancer

The renin-angiotensin system (RAS) is a network of proteins regulating many aspects of human physiology, including cardiovascular, pulmonary, and immune system physiology. The RAS is a complicated network of G-protein coupled receptors (GPCRs) (i.e., AT1R, AT2R, MASR, and MRGD) orchestrating the effects of several hormones (i.e., angiotensin II, angiotensin (1-7), and alamandine) produced by protease-based transmembrane receptors (ACE1 and ACE2). Two signaling axes have been identified in the RAS endocrine system that mediate the proliferative actions of angiotensin II (i.e., the AT1R-based pathway) or the anti-proliferative effects of RAS hormones (i.e., the AT2R-, MAS-, and MRGD-based pathways). Disruption of the balance between these two axes can cause different diseases (e.g., cardiovascular pathologies and the severe acute respiratory syndrome coronavirus 2- (SARS-CoV-2)-based COVID-19 disease). It is now accepted that all the components of the RAS endocrine system are expressed in cancer, including cancer of the breast. Breast cancer (BC) is a multifactorial pathology for which there is a continuous need to identify novel drugs. Here, I reviewed the possible roles of both axes of the RAS endocrine network as potential druggable pathways in BC. Remarkably, the analysis of the current knowledge of the different GPCRs of the RAS molecular system not only confirms that AT1R could be considered a drug target and that its inhibition by losartan and candesartan could be useful in the treatment of BC, but also identifies Mas-related GPCR member D (MRGD) as a druggable protein. Overall, the RAS of GPCRs offers multifaceted opportunities for the development of additional compounds for the treatment of BC.