Apelin-13 alleviates intrauterine adhesion by inhibiting epithelial-mesenchymal transition of endometrial epithelial cells and promoting angiogenesis.

Intrauterine adhesion (IUA) is a common complication of surgical manipulation of the uterine cavity such as abortion. The pathology of IUA is characterized by fibrosis, but the pathogenesis is not fully understood. The function of Apelin-13 in IUA and related mechanisms were investigated in this study. The IUA rat model was established. The pathological changes and fibrosis degree of rat uterine tissues were detected by HE and Masson staining after intraperitoneal injection of Apelin-13. Epithelial-mesenchymal transition (EMT) of endometrial epithelial cells and endothelial-mesenchymal transition (EnMT) of vein endothelial cells were induced by TGF-ß1. Tube-forming assay using HUVEC was implemented to detect the effect of Apelin-13 upon angiogenesis. IHC staining, immunofluorescence staining, and Western blot were conducted to detect the expression levels of EMT markers, angiogenesis, and key proteins of the TGF-ß1/Smad signaling. Apelin-13 significantly alleviated IUA and fibrosis, and increased endometrial thickness and gland number in IUA rats. In addition, Apelin-13 significantly reversed EMT and EnMT induced by IUA modeling and TGF-ß1, promoted the tube-forming ability of HUVEC, and up-regulated the expression of angiogenesis-related proteins. Mechanistically, Apelin-13 significantly suppressed smad2/3 phosphorylation and inhibited the TGF-ß1/Smad signaling via its receptor APJ. Apelin-13 might alleviate IUA via repressing the TGF-ß1/Smad pathway and is expected to be a potent therapeutic option for the clinical treatment of IUA.

Apelin-13 administration allows for norepinephrine sparing in a rat model of cecal ligation and puncture-induced septic shock.

BACKGROUND: Infusion of exogenous catecholamines (i.e., norepinephrine [NE] and dobutamine) is a recommended treatment for septic shock with myocardial dysfunction. However, sustained catecholamine infusion is linked to cardiac toxicity and impaired responsiveness. Several pre-clinical and clinical studies have investigated the use of alternative vasopressors in the treatment of septic shock, with limited benefits and generally no effect on mortality. Apelin-13 (APL-13) is an endogenous positive inotrope and vasoactive peptide and has been demonstrated cardioprotective with vasomodulator and sparing life effects in animal models of septic shock. A primary objective of this study was to evaluate the NE-sparing effect of APL-13 infusion in an experimental sepsis-induced hypotension. METHODS: For this goal, sepsis was induced by cecal ligation and puncture (CLP) in male rats and the arterial blood pressure (BP) monitored continuously via a carotid catheter. Monitoring, fluid resuscitation and experimental treatments were performed on conscious animals. Based on pilot assays, normal saline fluid resuscitation (2.5 mL/Kg/h) was initiated 3 h post-CLP and maintained up to the endpoint. Thus, titrated doses of NE, with or without fixed-doses of APL-13 or the apelin receptor antagonist F13A co-infusion were started when 20% decrease of systolic BP (SBP) from baseline was achieved, to restore SBP values ≥ 115 ± 1.5 mmHg (baseline average ± SEM). RESULTS: A reduction in mean NE dose was observed with APL-13 but not F13A co-infusion at pre-determined treatment time of 4.5 ± 0.5 h (17.37 ± 1.74 µg/Kg/h [APL-13] vs. 25.64 ± 2.61 µg/Kg/h [Control NE] vs. 28.60 ± 4.79 µg/Kg/min [F13A], P = 0.0491). A 60% decrease in NE infusion rate over time was observed with APL-13 co-infusion, (p = 0.008 vs NE alone), while F13A co-infusion increased the NE infusion rate over time by 218% (p = 0.003 vs NE + APL-13). Associated improvements in cardiac function are likely mediated by (i) enhanced left ventricular end-diastolic volume (0.18 ± 0.02 mL [Control NE] vs. 0.30 ± 0.03 mL [APL-13], P = 0.0051), stroke volume (0.11 ± 0.01 mL [Control NE] vs. 0.21 ± 0.01 mL [APL-13], P < 0.001) and cardiac output (67.57 ± 8.63 mL/min [Control NE] vs. 112.20 ± 8.53 mL/min [APL-13], P = 0.0036), and (ii) a reduced effective arterial elastance (920.6 ± 81.4 mmHg/mL/min [Control NE] vs. 497.633.44 mmHg/mL/min. [APL-13], P = 0.0002). APL-13 administration was also associated with a decrease in lactate levels compared to animals only receiving NE (7.08 ± 0.40 [Control NE] vs. 4.78 ± 0.60 [APL-13], P < 0.01). CONCLUSION: APL-13 exhibits NE-sparing benefits in the treatment of sepsis-induced shock, potentially reducing deleterious effects of prolonged exogenous catecholamine administration.

Exploring the potential roles of apelin, visfatin, and irisin in energy regulation in farm animals: an overview.

Adipose tissue, both intricate and fundamental to physiological functions, comprises cell types, including adipocytes, pivotal in secreting bioactive peptides known as 'adipokines.' Apelin (APLN), Visfatin (VSFTN), and Irisin (IRSN) are novel adipokines involved in regulating energy, carbohydrate, protein, and lipid metabolism. APLN acts as an endogenous ligand for G-protein-coupled receptors, VSFTN is essential in nicotinamide adenine dinucleotide (NAD) biosynthesis, and IRSN is released from skeletal muscle and adipose tissues. Their influence spans various physiological domains, including insulin resistance and sensitivity, cardiovascular functions, angiogenesis, and reproductive systems. This review focuses on the potential roles of APLN, VSFTN, and IRSN in energy regulation mechanisms related to farm animal production. Despite accumulating evidence of their significance, comprehensive understanding is still emerging, with most studies based on model organisms. Thus, there's a pressing need for targeted research on farm animals. Addressing these knowledge gaps could pave the way for improved health strategies, reproductive efficiency, and productivity in farm animals. Future research should focus on understanding the multifaceted interactions of these adipokines and their implications for promoting sustainable and effective animal production.

Effects of apelin on neonatal brain neurogenesis in L-NAME-induced maternal preeclampsia.

The aim of this study was to investigate the possible protective effects of apelin, which is known to have antioxidant and anti-inflammatory effects, on changes in neurogenesis in newborns of pregnant rats with L-NAME-induced preeclampsia. Wistar albino female rats were divided into four experimental groups: Control, Apelin, Preeclampsia and Preeclampsia + Apelin. Blood pressure was measured on the 5th, 11th and 17th days of gestation, urine protein was analyzed from urine samples collected for 24 h on the 6th, 12th and 18th days and serum creatinine was analyzed from serum samples. Maternal kidney and placenta tissues were obtained to establish the preeclampsia model, and neonatal brain tissues including the cortex, hippocampus and cerebellum regions were obtained to investigate neurogenesis and examined by histological and immunohistochemical methods. The number of newborns, body weight and brain weight of the newborns were measured. eNOS, IL-10, nNOS and NO levels in the brain analyzed via ELISA. Mean arterial pressure, urine protein and serum creatinine increased in the preeclampsia. Newborn weight decreased in the Preeclampsia group, the values in the Preeclampsia + Apelin group were closer to the Control and Apelin groups. In the Preeclampsia group, edema and dilatation in the proximal and distal tubules of kidneys, perivillous fibrin deposition and increase in syncytial nodules of placenta were observed. VEGF immunoreactivity decreased and iNOS immunoreactivity increased in both kidney and placenta. In neonatal brain tissue examinations, cytotoxic edema accompanied by thinning of cortex, delayed migration and lower cell counts in the hippocampus, and increase in intercellular spaces and EGL thickening in the cerebellum were observed in the preeclampsia. Expression of NeuN, GFAP, MBP, IL-10, eNOS, nNOS and NO levels decreased, whereas expression of Iba-1 increased in the preeclampsia. In the Preeclampsia + Apelin group, these findings were similar to the Control and Apelin groups. Apelin administration was found to be beneficial for preventing the adverse consequences of preeclampsia, but further experimental and clinical studies are needed to better understand these effects.

An update on novel and emerging therapeutic targets in Parkinson's disease.

Parkinson's Disease (PD) remains a significant focus of extensive research aimed at developing effective therapeutic strategies. Current treatments primarily target symptom management, with limited success in altering the course of the disease. This shortfall underscores the urgent need for novel therapeutic approaches that can modify the progression of PD.This review concentrates on emerging therapeutic targets poised to address the underlying mechanisms of PD. Highlighted novel and emerging targets include Protein Abelson, Rabphilin-3 A, Colony Stimulating Factor 1-Receptor, and Apelin, each showing promising potential in preclinical and clinical settings for their ability to modulate disease progression. By examining recent advancements and outcomes from trials focusing on these targets, the review aims to elucidate their efficacy and potential as disease-modifying therapies.Furthermore, the review explores the concept of multi-target approaches, emphasizing their relevance in tackling the complex pathology of PD. By providing comprehensive insights into these novel targets and their therapeutic implications, this review aims to guide future research directions and clinical developments toward more effective treatments for PD and related neurodegenerative disorders.

Potential biomarkers of ASD a target for future treatments: oxidative stress, chemokines, apoptotic, and methylation capacity.

OBJECTIVES: The study aimed to assess the effect of these biomarkers on a sample of children with autism spectrum disorder (ASD) to help in early diagnosis and intervention. METHODS: A total of 71 autistic patients and 65 normal controls were enrolled in this study. Their ages ranged from 5 to 11 years (mean ± SD 7.47 ± 3.81). Childhood Autism Rating Scale (CARS) was assessed for all patients and controls. Assessment of oxidative stress, monocyte chemoattractant protein-1, B-cell lymphoma 2, S-adenosylhomocysteine (SAH), and apelin was performed. RESULTS: Oxidative stress (oxidized low-density lipoprotein and malonaldehyde) increased while antioxidant paraoxonase (PON) decreased. Monocyte chemoattractant protein-1, B-cell lymphoma 2, and S-adenosylhomocysteine (SAH) were all elevated whereas, apelin was downregulated. CONCLUSIONS: It is important to note that many factors that may contribute to ASD including genetic factors. To open the door for novel treatment strategies, it is still necessary to precisely understand how oxidative stress, chemokines, apoptosis, and methylation capability affect the metabolism of people with ASD.

Apelin Receptor Homodimerisation Inhibits Hippocampal Neuronal Autophagy via G Protein-Dependent Signalling in Vascular Dementia.

Vascular dementia (VD), a progressive vascular cognitive impairment, is characterised by the presence of cerebral hypoperfusion, increased blood-brain barrier permeability, and white matter lesions. Although current treatment strategies primarily focus on risk factors such as hypertension, diabetes, and heart disease, efficient and targeted therapies are lacking and the underlying mechanisms of VD remain unclear. We previously discovered that Apelin receptors (APJ), which are G protein-coupled receptors (GPCRs), can homodimerize and generate signals that are distinct from those of APJ monomers in VD rats. Apelin-13 reduces the level of APJ homodimers and leads to the proliferation of endogenous neural stem cells in the hippocampal dentate gyrus area, suggesting that it has a neuroprotective role. In this study, we established a rat and cellular oxygen-glucose deprivation/reoxygenation VD model to investigate the impact of APJ homodimerisation on autophagy. We found that APJ homodimers protect against VD by inhibiting autophagy through the Gαq and PI3K/Akt/mTOR pathways upon Gαi signalling, both in vivo and in vitro. This discovery provides a promising therapeutic target for chronic cerebral ischaemia-reperfusion diseases and an experimental foundation for the development of drugs that target APJ homodimers.

Comparative Effects of Gymnema sylvestre and Berberine on Adipokines, Body Composition, and Metabolic Parameters in Obese Patients: A Randomized Study.

Gymnema sylvestre (GS) and berberine (BBR) are natural products that have demonstrated therapeutic potential for the management of obesity and its comorbidities, as effective and safe alternatives to synthetic drugs. Although their anti-obesogenic and antidiabetic properties have been widely studied, comparative research on their impact on the gene expression of adipokines, such as resistin (Res), omentin (Ome), visfatin (Vis) and apelin (Ap), has not been reported. METHODOLOGY: We performed a comparative study in 50 adult Mexican patients with obesity treated with GS or BBR for 3 months. The baseline and final biochemical parameters, body composition, blood pressure, gene expression of Res, Ome, Vis, and Ap, and safety parameters were evaluated. RESULTS: BBR significantly decreased (p < 0.05) body weight, blood pressure and Vis and Ap gene expression and increased Ome, while GS decreased fasting glucose and Res gene expression (p < 0.05). A comparative analysis of the final measurements revealed a lower gene expression of Ap and Vis (p < 0.05) in patients treated with BBR than in those treated with GS. The most frequent adverse effects in both groups were gastrointestinal symptoms, which attenuated during the first month of treatment. CONCLUSION: In patients with obesity, BBR has a better effect on body composition, blood pressure, and the gene expression of adipokines related to metabolic risk, while GS has a better effect on fasting glucose and adipokines related to insulin resistance, with minimal side effects.

Targeting Adipokines: A Promising Therapeutic Strategy for Epilepsy.

Epilepsy affects 65 million people globally and causes neurobehavioral, cognitive, and psychological defects. Although research on the disease is progressing and a wide range of treatments are available, approximately 30% of people have refractory epilepsy that cannot be managed with conventional medications. This underlines the importance of further understanding the condition and exploring cutting-edge targets for treatment. Adipokines are peptides secreted by adipocyte's white adipose tissue, involved in controlling food intake and metabolism. Their regulatory functions in the central nervous system (CNS) are multifaceted and identified in several physiology and pathologies. Adipokines play a role in oxidative stress and neuroinflammation which are associated with brain degeneration and connected neurological diseases. This review aims to highlight the potential impacts of leptin, adiponectin, apelin, vaspin, visfatin, and chimerin in the pathogenesis of epilepsy.

Hyperandrogenemia elevates expression of apelin and apelin receptor protein in the mice pituitary.

Hyperandrogenemia is associated with polycystic ovarian syndrome (PCOS) and imbalances in the pituitary hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels. Apelin and its receptor, APJ (class A, rhodopsin-like G- protein-coupled receptor), belongs to adipokines, and its expression has been shown in the pituitary. It is also well known that, hyperandrogenism and PCOS have deregulation of different adipokines. Whether hyperandrogenism also deregulates the apelin system in the pituitary has yet to be investigated. Thus, we have investigated the expression and localization of apelin and its receptor, APJ, in the letrozole-induced hyperandrogenised pituitary of female mice. Our results showed that the apelin, APJ and androgen receptor (AR) expression were upregulated in the anterior pituitary. Furthermore, the immunostaining of LH exhibited increased abundance than FSH. The circulating LH was also found to be elevated compared to FSH levels. The increased LH synthesis and secretion coincides with elevated apelin system in the pituitary of hyperandrogenised mice. Recently, a direct role of apelin has also been reported in the female pituitary, where apelin inhibits LH secretion. Thus, apelin could be one of the factors for deregulated gonadotropin secretion in hyperandrogenised conditions. However, more research is needed to fully understand the complex interactions between apelin and androgen regarding gonadotropin secretion in hyperandrogenised conditions.

RUNX3-activated apelin signaling inhibits cell proliferation and fibrosis in diabetic nephropathy by regulation of the SIRT1/FOXO pathway.

BACKGROUND: Diabetic nephropathy is a major secondary cause of end-stage renal disease. Apelin plays an important role in the development of DN. Understanding the exact mechanism of Apelin can help expand the means of treating DN. METHODS: Male C57BL/6 mice was used and STZ treatment was implemented for DN model establishment. Lentivirus systems including Lv-sh-RUNX3 and Lv-Apelin were obtained to knockdown RUNX3 and overexpress Apelin, respectively. A total of 36 mice were divided into 6 groups (n = 6 in each group): control, DN, DN + LV-Vector, DN + Lv-Apelin, DN + LV-Apelin + LV-sh-NC and DN + Lv-Apelin + Lv-sh-RUNX3 group. In vitro studies were performed using mesangial cells. Cell viability and proliferation was assessed through CCK8 and EDU analysis. Hematoxylin and eosin staining as well as Masson staining was implemented for histological evaluation. RT-qPCR was conducted for measuring relative mRNA levels, and protein expression was detected by western blotting. The interaction between SIRT1 and FOXO were verified by co-immunoprecipitations, and relations between RUNX3 and Apelin were demonstrated by dual luciferase report and chromatin immunoprecipitation. RESULTS: The DN group exhibited significantly lower Apelin expression compared to control (p < 0.05). Apelin overexpression markedly improved blood glucose, renal function indicators, ameliorated renal fibrosis and reduced fibrotic factor expression (p < 0.05) in the DN group, accompanied by elevated sirt1 levels and diminished acetylated FOXO1/FOXO3a (p < 0.05). However, RUNX3 knockdown combined with Apelin overexpression abrogated these beneficial effects, leading to impaired renal function, exacerbated fibrosis, increased fibrotic factor expression and acetylated FOXO1/FOXO3a versus Apelin overexpression alone (p < 0.05). In mesangial cells under high glucose, Apelin overexpression significantly inhibited cell proliferation and fibrotic factor production (p < 0.05). Conversely, RUNX3 interference enhanced cell proliferation and the secretion of fibrotic factors. (p < 0.05). Remarkably, combining Apelin overexpression with RUNX3 interference reversed the proliferation and fibrosis induced by RUNX3 interference (p < 0.05). Mechanistic studies revealed RUNX3 binds to the Apelin promoter, with the 467-489 bp site1 as the primary binding region, and SIRT1 physically interacts with FOXO1 and FOXO3a in mesangial cells. CONCLUSION: RUNX3 activated Apelin and regulated the SIRT1/FOXO signaling pathway, resulting in the suppressed cell proliferation and fibrosis in diabetic nephropathy. Apelin is a promising endogenous therapeutic target for anti-renal injury and anti-fibrosis in diabetic nephropathy. RUNX3 may serve as an endogenous intervention target for diseases related to Apelin deficiency.

Exploring the therapeutic potential: Apelin-13's neuroprotective effects foster sustained functional motor recovery in a rat model of Huntington's disease.

Huntington's disease (HD) is a hereditary condition considered by the progressive degeneration of nerve cells in the brain, resultant in motor dysfunction and cognitive impairment. Despite current treatment modalities including pharmaceuticals and various therapies, a definitive cure remains elusive. Therefore, this study investigates the therapeutic potential effect of Apelin-13 in HD management. Thirty male Wistar rats were allocated into three groups: a control group, a group with HD, and a group with both HD and administered Apelin-13. Apelin-13 was administered continuously over a 28-day period at a dosage of around 30 mg/kg to mitigate inflammation in rats subjected to 3-NP injection within an experimental HD model. Behavioral tests, such as rotarod, electromyography (EMG), elevated plus maze, and open field assessments, demonstrated that Apelin-13 improved motor function and coordination in rats injected with 3-NP. Apelin-13 treatment significantly increased neuronal density and decreased glial cell counts compared to the control group. Immunohistochemistry analysis revealed reduced gliosis and expression of inflammatory factors in the treatment group. Moreover, Apelin-13 administration led to elevated levels of glutathione and reduced reactive oxygen species (ROS) level in the treated group. Apelin-13 demonstrates neuroprotective effects, leading to improved movement and reduced inflammatory and fibrotic factors in the HD model.

Circ_0043314 Modulates Proliferation and Apoptosis of Ovarian Granulosa Cells in Polycystic Ovarian Syndrome via the MicroRNA-146b-3p/Apelin 13 Axis.

INTRODUCTION: Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women. At present, the pathogenesis has not been clarified, and the clinical application of drugs and lifestyle intervention may not prevent disease progression. This study aimed to investigate how circ_0043314 regulates ovarian granulosa cell biological functions to provide a theoretical basis for the treatment of patients with PCOS. MicroRNA (miR)-146b-3p/Apelin 13 axis was used to investigate the mechanism by which circ_0043314 regulated ovarian granulosa cell proliferation and apoptosis in PCOS via miR-146b-3p/Apelin 13 axis. Participants/Materials, Methods: Ovarian tissues (cortical tissues) from 35 PCOS patients and 35 normal controls, as well as HEK293T and human ovarian granulosa cell line (KGN, COV434), were included in this study. We examined the expression levels of circ_0043314, miR-146b-3p, and Apelin 13 in PCOS tissues. Ovarian granulosa cells were transfected with corresponding plasmids to clarify the influence of circ_0043314, miR-146b-3p, or Apelin 13 on proliferation and apoptosis of ovarian granulosa cells through MTT and flow cytometry assays. Moreover, the relationships among circ_0043314, miR-146b-3p, and Apelin 13 were analyzed through dual-luciferase and RNA immunoprecipitation assays. RESULTS: Circ_0043314 and Apelin 13 were highly expressed and miR-146b-3p was lowly expressed in ovarian tissues of PCOS compared with non-PCOS controls. Downregulation of circ_0043314 or upregulation of miR-146b-3p hindered ovarian granulosa cell proliferation and advanced its apoptosis. Downregulation of miR-146b-3p reversed the impacts of downregulation of circ_0043314, and overexpression of Apelin 13 counteracted the influences of upregulation of miR-146b-3p in ovarian granulosa cells. Mechanically, circ_0043314 could bind to miR-146b-3p, and miR-146b-3p directly targeted and modulated Apelin 13 expression. LIMITATIONS: This study was limited by the lack of animal experiments. CONCLUSION: Our data demonstrated that circ_0043314 enhances ovarian granulosa cell proliferation and suppresses its apoptosis via miR-146b-3p/Apelin 13 axis.

Potential relationships between apelin and metabolic-associated indices in transition dairy cows.

Metabolic disorders pose significant challenges in transition dairy cows. Numerous parameters have been investigated in this context, and apelin has recently emerged as a potential metabolic indicator. Accordingly, this study aimed to assess the associations between this hormone and other metabolic parameters. Twenty-two adult Holstein-Friesian dairy cows, 21 days before their expected calving date, were selected for blood sampling and serum separation at four time points: 21 and 10 days before calving and 10 and 21 days after parturition. Serum concentrations of apelin, leptin, insulin, cortisol, T3, T4, non-esterified fatty acids, glucose, total protein, albumin, globulin, aspartate aminotransferase, alanine transaminase, triglycerides, cholesterol, high, low and very low-density lipoproteins, total, direct and indirect bilirubin were measured in these samples. Surrogate indices for insulin resistance, body condition score, and milk production were also evaluated. Throughout the transition period, a significant increase in apelin levels was observed. Various models were employed to identify associations between apelin and the studied metabolic parameters. Notably, significant correlations between apelin and Leptin, Insulin, Cortisol, T3, T4, NEFA, Cholesterol, LDL, VLDL, Total Protein, Albumin, Globulin, Total Bilirubin, Direct Bilirubin and Indirect Bilirubin were observed, with some being immediate while others developed over time. These findings indicate a mutual influence between apelin and specific metabolic indices. Changes in any component of the metabolic profile at one stage can lead to alterations in apelin levels in subsequent stages. The correlations uncovered between apelin and other components of the metabolic profile in transitioning dairy cows offer valuable insights, contributing to a better understanding of the potential effects of apelin on the studied indicators and vice versa.

Adaptive enzyme-responsive self-assembling multivalent apelin ligands for targeted myocardial infarction therapy.

Microvascular dysfunction following myocardial infarction exacerbates coronary flow obstruction and impairs the preservation of ventricular function. The apelinergic system, known for its pleiotropic effects on improving vascular function and repairing ischemic myocardium, has emerged as a promising therapeutic target for myocardial infarction. Despite its potential, the natural apelin peptide has an extremely short circulating half-life. Current apelin analogs have limited receptor binding efficacy and poor targeting, which restricts their clinical applications. In this study, we utilized an enzyme-responsive peptide self-assembly technique to develop an enzyme-responsive small molecule peptide that adapts to the expression levels of matrix metalloproteinases in myocardial infarction lesions. This peptide is engineered to respond to the high concentration of matrix metalloproteinases in the lesion area, allowing for precise and abundant presentation of the apelin motif. The changes in hydrophobicity allow the apelin motif to self-assemble into a supramolecular multivalent peptide ligand-SAMP. This self-assembly behavior not only prolongs the residence time of apelin in the myocardial infarction lesion but also enhances the receptor-ligand interaction through increased receptor binding affinity due to multivalency. Studies have demonstrated that SAMP significantly promotes angiogenesis after ischemia, reduces cardiomyocyte apoptosis, and improves cardiac function. This novel therapeutic strategy offers a new approach to restoring coronary microvascular function and improving damaged myocardium after myocardial infarction.

The extract of an herbal medicine Chebulae fructus inhibits hepatocellular carcinoma by suppressing the Apelin/APJ system.

Introduction: Hepatocellular carcinoma (HCC) has been a highly common and pathological disease worldwide, while current therapeutic regimens have limitations. Chebulae Fructus, a common herbal medicine in Asia, has been documented to exert potential therapeutic effects on HCC in ancient medicine clinical practice. However, the molecular mechanism underlying its inhibitory effects on HCC requires further investigation. Methods: In this study, the anti-HCC effect of the aqueous extract of Chebulae Fructus (CFE) on human HCC and its underlying mechanism were evaluated. Assays including CCK8, EdU staining, crystal violet staining, cell clone formation, flow cytometry, wound healing, and transwell were used in vitro. The cell-derived xenograft (CDX) and patient-derived xenograft (PDX) models were used in vivo. Transcriptomics analysis, qRT-PCR, ELISA, IHC staining, and Western blotting were employed to determine the mechanism of action of CFE. Results: The results demonstrate that CFE effectively suppressed the proliferation and activity of HepG2 and PLC/PRF/5 HCC cells. CFE also induced apoptosis, and suppressed the migration and invasion abilities of these cells. Furthermore, CFE exhibited inhibitory effects on tumor growth in both H22 and PLC/PRF/5 mouse models, as well as in an HCC PDX model which is derived from patient tumor samples. Moreover, it was identified that CFE treatment specifically suppressed the Apelin/APJ system in HCC cells and tumor tissues. To investigate the role of the Apelin/APJ system in mediating the effects of CFE treatment, an APJ overexpressed cell model is established. Interestingly, it was found that the overexpression of APJ significantly diminished the inhibitory effects of CFE on HCC in vitro. Discussion: Collectively, this study provides compelling evidence that CFE exerts significant anti-HCC effects in cell and animal models. Moreover, our findings suggest that the Apelin/APJ system may play a vital role in the therapeutic effects of CFE against HCC.

Fluorinated apelin-13 mediates neuroprotective effects in multiple sclerosis models.

Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease leading to demyelination and axonal loss. Current treatments are immunomodulatory or immunosuppressive drugs acting on the inflammatory component. However, these treatments do not adequately address the crucial aspect of neuroprotection. Recently, an association between an altered balance of adipokines and MS has been proposed as both a risk factor for developing MS and a chronic disease aggravating factor. Specifically, a decrease of apelin plasma levels in MS patients compared to controls correlates with the number of relapses and disease severity. Here we report a dramatic downregulation of apelin levels in the CNS of EAE mice which is also detected in MS patients brain samples compared to controls. Exploiting innovative design and synthesis techniques, we engineered a novel fluorinated apelin-13 peptide characterized by enhanced plasmatic stability compared to its native counterpart. With this peptide, we assessed the potential therapeutic benefits of apelin preventive supplementation in the EAE mouse model. We show that the fluorinated Apelin-13 peptide ameliorates EAE clinical score and preserves myelin content in the EAE MOG model recapitulating the progressive form of disease. These results combined with ex-vivo experiments in brain organotypic slices and in vitro studies in neurons and primary microglia and macrophages suggest that apelin has neuroprotective effects and influences the microglia/macrophages function.

The flavonoid quercetin decreases ACE2 and TMPRSS2 expression but not SARS-CoV-2 infection in cultured human lung cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to angiotensin-converting enzyme 2 (ACE2) on host cells, via its spike protein, and transmembrane protease, serine 2 (TMPRSS2) cleaves the spike-ACE2 complex to facilitate virus entry. As rate-limiting steps for virus entry, modulation of ACE2 and/or TMPRSS2 may decrease SARS-CoV-2 infectivity and COVID-19 severity. In silico modeling suggested the natural bioactive flavonoid quercetin can bind to ACE2 and a recent randomized clinical trial demonstrated that oral supplementation with quercetin increased COVID-19 recovery. A range of cultured human cells were assessed for co-expression of ACE2 and TMPRSS2. Immortalized Calu-3 lung cells, cultured and matured at an air-liquid interface (Calu-3-ALIs), were established as the most appropriate. Primary bronchial epithelial cells (PBECs) were obtained from healthy adult males (N = 6) and cultured under submerged conditions to corroborate the outcomes. Upon maturation or reaching 80% confluence, respectively, the Calu-3-ALIs and PBECs were treated with quercetin, and mRNA and protein expression were assessed by droplet digital PCR and ELISA, respectively. SARS-CoV-2 infectivity, and the effects of pre- and co-treatment with quercetin, was assessed by median tissue culture infectious dose assay. Quercetin dose-dependently decreased ACE2 and TMPRSS2 mRNA and protein in both Calu-3-ALIs and PBECs after 4 h, while TMPRSS2 remained suppressed in response to prolonged treatment with lower doses (twice daily for 3 days). Quercetin also acutely decreased ADAM17 mRNA, but not ACE, in Calu-3-ALIs, and this warrants further investigation. Calu-3-ALIs, but not PBECs, were successfully infected with SARS-CoV-2; however, quercetin had no antiviral effect, neither directly nor indirectly through downregulation of ACE2 and TMPRSS2. Calu-3-ALIs were reaffirmed to be an optimal cell model for research into the regulation of ACE2 and TMPRSS2, without the need for prior genetic modification, and will prove valuable in future coronavirus and respiratory infectious disease work. However, our data demonstrate that a significant decrease in the expression of ACE2 and TMPRSS2 by a promising prophylactic candidate may not translate to infection prevention.

Hormonal dependent expression of apelin and apelin receptor in the ovary and uterus of mice.

Apelin and APJ have been shown to regulate female reproductive functions. However, its uterine expression during the oestrous cycle and its regulation by ovarian steroids, along with gonadotropin regulation in the ovary, has not been investigated. This study aimed to analyze the steroid-dependent uterine expression of apelin/APJ in the uterus along with the oestrous cycle. Furthermore, it also aimed to investigate gonadotropin-dependent ovarian expression of apelin and APJ. To investigate the uterine expression of apelin and APJ during estrous cycle in mice, uterus at different estrous stage were collected. To explore the ovarian steroids dependent expression of apelin system in the uterus, ovariectomized mice were treated with only estrogen at dose of 30 ng/g, only progesterone at dose of 150 µg/g and combined doses. To study the effect of gonadotropin on ovarian expression of apelin system, immature mice were injected with 2.5 IU of pregnant mare serum gonadotropin (PMSG) alone and both PMSG plus 2.5 IU of chorionic gonadotropin (hCG). Apelin and APJ protein expression are modulated by estrous phases in the uterus. The uterine apelin and APJ expression are up-regulated by estrogen and down-regulated by progesterone. The expression and localization of APJ showed increased abundance in the follicles of PMSG treated mice, however, the PMSG plus HCG treatment showed formation of corpus luteum with increased abundance of APJ and progesterone secretion. The expression of apelin and APJ are regulated by pituitary gonadotropin in the ovary and uterine apelin system by ovarian steroid hormone.

Apelin and Copeptin Levels in Patients With Chronic SIAD Treated With Empagliflozin.

Background: Empagliflozin increases sodium levels in patients with a chronic syndrome of inappropriate antidiuresis (SIAD), and dapagliflozin increases apelin levels in patients with diabetes mellitus. Exogenous apelin increases sodium levels in rats with SIAD. We aimed to investigate whether an increase in plasma apelin concentration may contribute to the efficacy of empagliflozin in SIAD. Methods: Post hoc secondary analysis of a double-blind, crossover, placebo-controlled trial performed from December 2017 to August 2021 at the University Hospital Basel, Switzerland, investigating the effect of 4-week treatment with empagliflozin 25 mg/day as compared to placebo in 14 outpatients with chronic SIAD (NCT03202667). The objective was to investigate the effect of empagliflozin on plasma apelin and copeptin concentrations and their ratio. Results: Fourteen patients, 50% female, with a median [interquartile range] age of 72 years [65-77] were analyzed. Median apelin concentration was 956 pmol/L [853, 1038] at baseline. Median [interquartile range] apelin relative changes were +11% [0.7, 21] and +8% [-5, 25] (P = .672) at the end of the placebo and empagliflozin phases, respectively. Median copeptin concentration was 2.6 [2.2, 4.5] pmol/L at baseline and had a relative change of +5 [-2. 11]% and +25% [10, 28] (P = .047) over the placebo and empagliflozin phases, respectively. Conclusion: Empagliflozin did not lead to significant changes in apelin or the apelin/copeptin ratio in patients with chronic SIAD but led to an increase in copeptin. This suggests that the efficacy of empagliflozin in SIAD is independent of apelin and is not blunted by the adaptative increase in copeptin.