Chronic infusion of ELABELA alleviates vascular remodeling in spontaneously hypertensive rats via anti-inflammatory, anti-oxidative and anti-proliferative effects

Elabela ameliorates neuronal pyroptosis and mitochondrial fission via APJ/ZBP1 signaling in ischemic stroke

Pyroptosis signifies a significant form of programmed neuronal demise subsequent to ischemic stroke. In our prior investigations, we demonstrated that the Elabela (ELA)-Apelin receptor (APJ) axis alleviated neuronal death by improving collateral circulation and mitigating ferroptosis in a murine model of middle cerebral artery occlusion (MCAO). However, the connection between ELA and neuronal pyroptosis remains further elucidation. Here, we observed an upregulation of ELA and APJ expression in both murine brain specimens and cultured HT-22 hippocampal neurons exposed to experimental ischemic stroke. ELA administration markedly diminished the infarct size in comparison to controls. ELA treatment ameliorated neurological deficits and anxiety-like symptoms in mice with stroke, concurrently inhibiting pyroptosis and mitochondria fission in neurons. Conversely, ELA knockdown yielded the opposite effects. Utilizing RNA-sequencing analysis, we identified a candidate for pyroptosis priming, Z-DNA-binding protein 1 (ZBP1), which was suppressed in ELA-treated HT-22 neurons during oxygen-glucose deprivation/reperfusion (OGD/R). Subsequent co-immunoprecipitation analyses demonstrated the binding between APJ and ZBP1. Specifically, APJ suppressed ZBP1 to inhibit NLRP3 inflammasome activation and dynamin-related protein 1-mediated mitochondrial fission in neurons. In summary, our findings suggest that ELA functions as a stroke-induced signal limiting neuronal pyroptosis and mitochondrial fission via APJ/ZBP1 signaling, thereby underscoring ELA as a potential therapeutic target for ischemic stroke treatment.

Transcriptome and proteome analyses reveal that upregulation of GSTM2 by allisartan improves cardiac remodeling and dysfunction in hypertensive rats

Long-term hypertension can lead to hypertensive heart disease, which ultimately progresses to heart failure. As an angiotensin receptor blocker antihypertensive drug, allisartan can control blood pressure, and improve cardiac remodeling and cardiac dysfunction caused by hypertension. The aim of the present study was to investigate the protective effects of allisartan on the heart of spontaneously hypertensive rats (SHRs) and the underlying mechanisms. SHRs were used as an animal model of hypertensive heart disease and were treated with allisartan orally at a dose of 25 mg/kg/day. The blood pressure levels of the rats were continuously monitored, their body and heart weights were measured, and their cardiac structure and function were evaluated using echocardiography. Wheat germ agglutinin staining and Masson trichrome staining were employed to assess the morphology of the myocardial tissue. In addition, transcriptome and proteome analyses were performed using the Solexa/Illumina sequencing platform and tandem mass tag technology, respectively. Immunofluorescence co-localization was conducted to analyze Nrf2 nuclear translocation, and TUNEL was performed to detect the levels of cell apoptosis. The protein expression levels of pro-collagen I, collagen III, phosphorylated (p)-AKT, AKT, p-PI3K and PI3K, and the mRNA expression levels of Col1a1 and Col3a1 were determined by western blotting and reverse transcription-quantitative PCR, respectively. Allisartan lowered blood pressure, attenuated cardiac remodeling and improved cardiac function in SHRs. In addition, allisartan alleviated cardiomyocyte hypertrophy and cardiac fibrosis. Allisartan also significantly affected the 'pentose phosphate pathway', 'fatty acid elongation', 'valine, leucine and isoleucine degradation', 'glutathione metabolism', and 'amino sugar and nucleotide sugar metabolism' pathways in the hearts of SHRs, and upregulated the expression levels of GSTM2. Furthermore, allisartan activated the PI3K-AKT-Nrf2 signaling pathway and inhibited cardiomyocyte apoptosis. In conclusion, the present study demonstrated that allisartan can effectively control blood pressure in SHRs, and improves cardiac remodeling and cardiac dysfunction. Allisartan may also upregulate the expression levels of GSTM2 in the hearts of SHRs and significantly affect glutathione metabolism, as determined by transcriptome and proteome analyses. The cardioprotective effect of allisartan may be mediated through activation of the PI3K-AKT-Nrf2 signaling pathway, upregulation of GSTM2 expression and reduction of cardiomyocyte apoptosis in SHRs.

An updated review of YAP: A promising therapeutic target against cardiac aging?

The transcriptional co-activator Yes-associated protein (YAP) functions as a downstream effector of the Hippo signaling pathway and plays a crucial role in cardiomyocyte survival. In its non-phosphorylated activated state, YAP binds to transcription factors, activating the transcription of downstream target genes. It also regulates cell proliferation and survival by selectively binding to enhancers and activating target genes. However, the upregulation of the Hippo pathway in human heart failure inhibits cardiac regeneration and disrupts astrogenesis, thus preventing the nuclear translocation of YAP. Existing literature indicates that the Hippo/YAP axis contributes to inflammation and fibrosis, potentially playing a role in the development of cardiac, vascular and renal injuries. Moreover, it is a key mediator of myofibroblast differentiation and fibrosis in the infarcted heart. Given these insights, can we harness YAP's regenerative potential in a targeted manner? In this review, we provide a detailed discussion of the Hippo signaling pathway and consolidate concepts for the development and intervention of cardiac anti-aging drugs to leverage YAP signaling as a pivotal target.

Wogonin attenuates vascular remodeling by inhibiting smooth muscle cell proliferation and migration in hypertensive rat

Wogonin, extracted from the roots of Scutellaria baicalensis Georgi, has been shown to suppress collagen deposition in spontaneously hypertensive rats (SHRs). This study was performed to investigate the role and mechanism of wogonin underlying vascular remodeling in SHRs. After injection of SHRs with 40 mg/kg of wogonin, blood pressure in rats was measured once a week. Masson's trichrome staining was conducted to observe the changes in aortas and mesenteric arteries. Vascular smooth muscle cells (VSMCs) isolated from rat thoracic aortas were treated with Angiotensin II (Ang II; 100 nM) in the presence or absence of varying concentrations of wogonin. The viability and proliferation of VSMCs were examined using Cell Counting Kit-8 assay and 5-ethynyl-2'-deoxyuridine assay, respectively. The migration of VSMCs was examined using wound healing assay and transwell assay. We found that wogonin administration alleviated hypertension, increased lumen diameter, and reduced the thickness of the arterial media in SHRs. Ang II treatment enhanced the viability of VSMCs, which was inhibited by wogonin in a concentration-dependent manner. Wogonin reversed Ang II-induced increases in the viability, proliferation, and migration of VSMCs. Moreover, wogonin inhibited Ang II-induced activation of mitogen-activated protein kinase (MAPK) signaling in VSMCs. Overall, wogonin repressed the proliferative and migratory capacity of VSMCs by regulating the MAPK signaling pathway, thereby attenuating vascular remodeling in hypertensive rats, indicating that wogonin might be a therapeutic agent for the treatment of vascular diseases.

A promising therapeutic peptide and preventive/diagnostic biomarker for age-related diseases: The Elabela/Apela/Toddler peptide

Elabela (ELA), Apela or Toddler peptide is a hormone peptide belonging to the adipokine group and a component of apelinergic system, discovered in 2013-2014. Given its high homology with apelin, the first ligand of APJ receptor, ELA likely mediates similar effects. Increasing evidence shows that ELA has a critical function not only in embryonic development, but also in adulthood, contributing to physiological and pathological conditions, such as the onset of age-related diseases (ARD). However, still little is known about the mechanisms and molecular pathways of ELA, as well as its precise functions in ARD pathophysiology. Here, we report the mechanisms by which ELA/APJ signaling acts in a very complex network of pathways for the maintenance of physiological functions of human tissue and organs, as well as in the onset of some ARD, where it appears to play a central role. Therefore, we describe the possibility to use the ELA/APJ pathway, as novel biomarker (predictive and diagnostic) and target for personalized treatments of ARD. Its potentiality as an optimal peptide candidate for therapeutic ARD treatments is largely described, also detailing potential current limitations.

Cardiovascular aspects of ELABELA: A potential diagnostic biomarker and therapeutic target

ELABELA, an early endogenous ligand for the G protein-coupled receptor APJ (apelin peptide jejunum, apelin receptor), has been known as an important regulator in cardiovascular homeostasis and may be a novel therapeutic target for multiple cardiovascular diseases (CVDs). At the physiological level, ELABELA exhibits angiogenic and vasorelaxant effects and is essential for heart development. At the pathological level, circulating ELABELA levels may be a novel diagnostic biomarker for various CVDs. ELABELA peripherally displays antihypertensive, vascular-protective, and cardioprotective effects, whereas central administration of ELABELA elevated BP and caused cardiovascular remodeling. This review highlights the physiological and pathological roles of ELABELA in the cardiovascular system. Enhancement of the peripheral ELABELA may be a promising pharmacological therapeutic strategy for CVDs.

ELABELA-APJ-Akt/YAP Signaling Axis: A Novel Mechanism of Aerobic Exercise in Cardioprotection of Myocardial Infarction Rats

PURPOSE

The aim of this study was to investigate the function and mechanisms of ELABELA (ELA) in the aerobic exercise-induced antiapoptosis and angiogenesis of ischemic heart.

METHODS

The myocardial infarction (MI) model of Sprague-Dawley rat was established by the ligation of the left anterior descending coronary artery. MI rats underwent 5 wk of Fc-ELA-21 subcutaneous injection and aerobic exercise training using a motorized rodent treadmill. Heart function was evaluated by hemodynamic measures. Cardiac pathological remodeling was evaluated by Masson's staining and the calculation of left ventricular weight index. Cell proliferation, angiogenesis, and Yes-associated protein (YAP) translocation were observed by immunofluorescence staining. Cell apoptosis was analyzed by TUNEL. Cell culture and treatment were used to elucidate the molecular mechanism of ELA. Protein expression was detected by Western blotting. Angiogenesis was observed by tubule formation test. One-way or two-way ANOVA and Student's t -test were used for statistical analysis.

RESULTS

Aerobic exercise stimulated the endogenous ELA expression. Exercise and Fc-ELA-21 intervention significantly activated APJ-Akt-mTOR-P70S6K signaling pathway, kept more cardiomyocytes alive, and increased angiogenesis, so as to inhibit the cardiac pathological remodeling and improved the heart function of MI rats. Fc-ELA-32 also had the cellular and functional cardioprotective activities in vivo . In vitro , ELA-14 peptide regulated the phosphorylation and nucleoplasmic translocation of YAP and activated the APJ-Akt signaling pathway so as to increase the proliferation of H9C2 cells. Moreover, the antiapoptosis and the tubule formation of HUVECs were also enhanced by ELA-14, whereas the inhibition of Akt activity weakened such effects.

CONCLUSIONS

ELA is a potential therapeutic member that plays a key role through APJ-Akt/YAP signaling axis in aerobic exercise-induced cardioprotection of MI rats.

Antioxidant Properties Mediate Nephroprotective and Hepatoprotective Activity of Essential Oil and Hydro-Alcoholic Extract of the High-Altitude Plant Skimmia anquetilia

There are many high-altitude plants such as Skimmia anquetilia that are unexplored for their possible medicinal values. The present study was conducted to examine the antioxidant activities of Skimmia anquetilia (SA) using in vitro and in vivo models. The SA hydro-alcoholic extracts were investigated using LC-MS for their chemical constituents. The essential oil and hydro-alcoholic extracts of SA were evaluated for pharmacological properties. The antioxidant properties were evaluated using in vitro DPPH, reducing power, cupric reducing antioxidant power, and metal chelating assays. The anti-hemolytic activity was carried out using a human blood sample. The in vivo antioxidant activities were evaluated using CCL₄-induced hepatotoxicity and nephrotoxicity assay. The in vivo evaluation included histopathological examination, tissue biochemical evaluation such as the kidney function test, catalase activity, reduced glutathione activity, and lipid peroxidation estimation. The phytochemical investigation showed that the hydro-alcoholic extract contains multiple important active constituents such as L-carnosine, acacetin, linoleic acid, leucylleucyl tyrosine, esculin sesquihydrate, etc., similar to the components of SA essential oil reported in a previous study. The high amount of total phenolic content (TPC) and total flavonoid content (TFC) reflect (p < 0.001) a high level of reducing power, cupric reducing, and metal chelating properties. This significantly (p < 0.001) inhibited enlargement of the liver, with a significant reduction in ALT (p < 0.01) and AST (p < 0.001). Highly significant improvement in the functioning of the kidney was noted using the blood urea and creatinine (p < 0.001) levels. Tissue-based activities showed a major rise in catalase, reduced glutathione, and reduced lipid peroxidation activities. We conclude from this study that the occurrence of a high quantity of flavonoid and phenolic contents had strong antioxidant properties, leading to hepatoprotective and nephroprotective activity. Further active constituent-specific activities should be evaluated.

Causal effects of circulating vitamin levels on the risk of heart failure: a Mendelian randomization study

BACKGROUND

Observational studies suggest inverse associations between serum vitamin levels and the risk of heart failure (HF). However, the causal effects of vitamins on HF have not been fully elucidated. Here, we conducted a Mendelian randomization (MR) study to investigate the causal associations between genetically determined vitamin levels and HF.

METHODS

Genetic instrumental variables for circulating vitamin levels, including vitamins A, B, C, D, and E, which were assessed as either absolute or metabolite levels were obtained from public genome-wide association studies. Summary statistics for single-nucleotide-polymorphisms and HF associations were retrieved from the HERMES Consortium (47,309 cases and 930,014 controls) and FinnGen Study (30,098 cases and 229,612 controls). Two-sample MR analyses were implemented to assess the causality between vitamin levels and HF per outcome database, and the results were subsequently combined by meta-analysis.

RESULTS

Our MR study did not find significant associations between genetically determined circulating vitamin levels and HF risk. For absolute vitamin levels, the odds ratio for HF ranged from 0.97 (95% confidence interval [CI]: 0.85-1.09, P = 0.41) for vitamin C to 1.05 (95% CI: 0.61-1.82, P = 0.85) for vitamin A. For vitamin metabolites, the odds ratio ranged between 0.94 (95% CI: 0.75-1.19, P = 0.62) for α-tocopherol and 1.11 (95% CI: 0.98-1.26, P = 0.09) for γ-tocopherol.

CONCLUSION

Evidence from our study does not support the causal effects of circulating vitamin levels on HF. Therefore, there may be no direct beneficial effects of vitamin intake on the prevention of primary HF.

Elabela-APJ axis attenuates cerebral ischemia/reperfusion injury by inhibiting neuronal ferroptosis

Ferroptosis is a form of non-apoptotic cell death caused by iron-dependent peroxidation of lipids. It contributes to ischemic stroke-induced neuronal damage. Elabela (ELA), a novel endogenous ligand for Apelin receptor (APJ), regulates oxidative stress and exerts a protective role in cardiovascular disease. However, the effect of ELA-APJ axis on cellular ferroptosis in cerebral ischemia/reperfusion (I/R) remains elusive. The present study showed that ELA and APJ were expressed on neurons and increased after cerebral I/R injury. The I/R insult triggered typical molecular and morphological features of neuronal ferroptosis, including iron and MDA accumulation, mitochondrial shrink and membrane rupture, upregulation of positive ferroptosis regulators and downregulation of negative regulators. ELA-32 treatment reduced brain infarction and ameliorated neurobehavioral deficits and cognitive dysfunction. Moreover, ELA-32 administration alleviated neuronal ferroptosis, accompanied by reduced iron deposition, decreased mitochondrial damage, relived lipid peroxidation and glutathione reduction. Such effects of ELA-32 were abolished by AAV-APJ-RNAi or nuclear factor erythroid 2-related factor 2 (NRF2) inhibitor ML385. Mechanistically, ELA was shown to bind to APJ and activate NRF2/ARE anti-oxidative signaling pathway via Gα13. Together, these findings suggested that ELA-APJ axis mitigates neuronal ferroptosis after ischemic stroke and that the ELA-32 peptide may be a putative therapeutic avenue for ischemic stroke.

Sexual Dimorphism in the Polarization of Cardiac ILCs through Elabela

Elabela is a component of the apelinergic system and may exert a cardioprotective role by regulating the innate immune responses. Innate lymphoid cells (ILCs) have a significant role in initiating and progressing immune-inflammatory responses. While ILCs have been intensively investigated during the last decade, little is known about their relationship with the apelinergic system and their cardiac diversity in a gender-based paradigm. In this study, we investigated the polarization of cardiac ILCs by Elabela in males versus females in a mouse model. Using flow cytometry and immunohistochemistry analyses, we showed a potential interplay between Elabela and cardiac ILCs and whether such interactions depend on sexual dimorphism. Our findings showed, for the first time, that Elabela is expressed by cardiac ILCs, and its expression is higher in females' ILC class 3 (ILC3s) compared to males. Females had higher frequencies of ILC1s, and Elabela was able to suppress T-cell activation and the expression of co-stimulatory CD28 in a mixed lymphocyte reaction assay (MLR). In conclusion, our results suggest, for the first time, a protective role for Elabela through its interplay with ILCs and that it can be used as an immunotherapeutic target in the treatment of cardiovascular disorders in a gender-based fashion.

Activation of Nrf2 signaling: A key molecular mechanism of protection against cardiovascular diseases by natural products

Cardiovascular diseases (CVD) are a group of cardiac and vascular disorders including myocardial ischemia, congenital heart disease, heart failure, hypertension, atherosclerosis, peripheral artery disease, rheumatic heart disease, and cardiomyopathies. Despite considerable progress in prophylaxis and treatment options, CVDs remain a leading cause of morbidity and mortality and impose an extremely high socioeconomic burden. Oxidative stress (OS) caused by disequilibrium in the generation of reactive oxygen species plays a crucial role in the pathophysiology of CVDs. Nuclear erythroid 2-related factor 2 (Nrf2), a transcription factor of endogenous antioxidant defense systems against OS, is considered an ideal therapeutic target for management of CVDs. Increasingly, natural products have emerged as a potential source of Nrf2 activators with cardioprotective properties and may therefore provide a novel therapeutic tool for CVD. Here, we present an updated comprehensive summary of naturally occurring products with cardioprotective properties that exert their effects by suppression of OS through activation of Nrf2 signaling, with the aim of providing useful insights for the development of therapeutic strategies exploiting natural products.

ERK/HIF-1α/VEGF pathway: a molecular target of ELABELA (ELA) peptide for attenuating cardiac ischemia-reperfusion injury in rats by promoting angiogenesis

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury is caused by a chain of events such as endothelial dysfunction. This study was conducted to investigate protective effects of ELABELA against myocardial I/R in Wistar rats and clarify its possible mechanisms. METHODS AND RESULTS: MI model was established based on the left anterior descending coronary artery ligation for 30 min. Then, 5 µg/kg of ELA peptide was intraperitoneally infused in rats once per day for 4 days. Western blot assay was used to assay the expression of t-ERK1/2, and p-ERK1/2 in different groups. The amount of myocardial capillary density, the expression levels of VEGF and HIF-1α were evaluated using immunohistochemistry assay. Masson's trichrome staining was utilized to assay cardiac interstitial fibrosis. The results showed that establishment of MI significantly enhanced cardiac interstitial fibrosis and changed p-ERK1/2/ t-ERK1/2 ratio. Likewise, ELA post-treatment markedly increased myocardial capillary density, the expression of several angiogenic factors (VEGF-A, HIF-1α), and reduced cardiac interstitial fibrosis by activation of ERK1/2 signaling pathways.

CONCLUSION

Collectively, ELA peptide has ability to reduce myocardial I/R injury by promoting angiogenesis and reducing cardiac interstitial fibrosis through activating ERK/HIF-1α/VEGF pathway.

β‑aminoisobutyric acid ameliorates hypertensive vascular remodeling via activating the AMPK/SIRT1 pathway in VSMCs

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play a fundamental role in the pathogenesis of hypertension-related vascular remodeling. β-aminoisobutyric acid (BAIBA) is a nonprotein β-amino acid with multiple pharmacological actions. Recently, BAIBA has been shown to attenuate salt‑sensitive hypertension, but the role of BAIBA in hypertension-related vascular remodeling has yet to be fully clarified. This study examined the potential roles and underlying mechanisms of BAIBA in VSMC proliferation and migration induced by hypertension. Primary VSMCs were cultured from the aortas of Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Our results showed that BAIBA pretreatment obviously alleviated the phenotypic transformation, proliferation, and migration of SHR-derived VSMCs. Exogenous BAIBA significantly inhibited the release of inflammatory cytokines by diminishing phosphorylation and nuclear translocation of p65 NFκB, retarding IκBα phosphorylation and degradation, as well as erasing STAT3 phosphorylation in VSMCs. Supplementation of BAIBA triggered Nrf2 dissociation from Keap1 and inhibited oxidative stress in VSMCs from SHR. Mechanistically, activation of the AMPK/sirtuin 1 (SIRT1) axis was required for BAIBA to cube hypertension-induced VSMC proliferation, migration, oxidative damage and inflammatory response. Most importantly, exogenous BAIBA alleviated hypertension, ameliorated vascular remodeling and fibrosis, abated vascular oxidative burst and inflammation in SHR, an effect that was abolished by deficiency of AMPKα1 and SIRT1. BAIBA might serve as a novel therapeutic agent to prevent vascular remodeling in the context of hypertension.