Egg ovotransferrin-derived ACE inhibitory peptide IRW increases ACE2 but decreases proinflammatory genes expression in mesenteric artery of spontaneously hypertensive rats

Differential Mechanisms of Soybean-Derived ACE2-Activating Peptides IVPQ and IAVPT in ACE2-Mediated Endothelial Protection

This study aimed to investigate the modulatory effects of soybean-derived peptides IVPQ and IAVPT, which were initially identified as potent ACE2-activating peptides, on Ang II-induced endothelial dysfunction in human umbilical vein endothelial cells (HUVECs) and the underlying mechanisms via ACE2 activation. IVPQ and IAVPT ameliorated Ang II-induced malignant migration and NO reduction in HUVECs via the activation of the ACE2/Ang-(1-7)/MasR axis, resulting in Ang II degradation and decreased Ang II signaling. These protective effects were attenuated by ACE2 knockdown to different degrees, which was possibly due to different mechanisms of activating ACE2, where IAVPT directly activated ACE2 at a concentration of 1.0 × 10-4 M and IVPQ upregulated ACE2 likely through effects on ACE2 mRNA stability. These results contributed to our understanding of the mechanism of ACE2-activating peptides regulating endothelial function.

Research Progress of Food-Derived Antihypertensive Peptides in Regulating the Key Factors of the Renin-Angiotensin System

Food protein-derived antihypertensive peptides have attracted substantial attention as a safer alternative for drugs. The regulation of the renin-angiotensin system (RAS) is an essential aspect underlying the mechanisms of antihypertensive peptides. Most of the identified antihypertensive peptides exhibit the angiotensin-converting enzyme (ACE) inhibitory effect. In addition, artificial intelligence has improved the efficiency of ACE inhibitory peptide identifications. Moreover, the inhibition of renin and blockade or down-regulation of angiotensin type I receptor (AT1R) have also been demonstrated to be effective intervention strategies. With the identification of the ACE2/Ang (1-7)/MasR axis, activation or up-regulation of angiotensin-converting enzyme 2 (ACE2) has also emerged as a new intervention pathway. This review summarizes the research progress of antihypertensive peptides in intervening with hypertension from the perspective of their properties, sources, and key factors. The objective of this review is to provide theoretical references for the development of antihypertensive peptides and the explorations of the molecular mechanisms.

Unexplored Opportunities of Utilizing Food Waste in Food Product Development for Cardiovascular Health

PURPOSE OF REVIEW

Global food production leads to substantial amounts of agricultural and food waste that contribute to climate change and hinder international efforts to end food insecurity and poverty. Food waste is a rich source of vitamins, minerals, fibers, phenolic compounds, lipids, and bioactive peptides. These compounds can be used to create food products that help reduce heart disease risk and promote sustainability. This review examines the potential cardiovascular benefits of nutrients found in different food waste categories (such as fruits and vegetables, cereal, dairy, meat and poultry, and seafood), focusing on animal and clinical evidence, and giving examples of functional food products in each category.

RECENT FINDINGS

Current evidence suggests that consuming fruit and vegetable pomace, cereal bran, and whey protein may lower the risk of cardiovascular disease, particularly in individuals who are at risk. This is due to improved lipid profile, reduced blood pressure and increased flow-mediated dilation, enhanced glucose and insulin regulation, decreased inflammation, as well as reduced platelet aggregation and improved endothelial function. However, the intervention studies are limited, including a low number of participants and of short duration. Food waste has great potential to be utilized as cardioprotective products. Longer-term intervention studies are necessary to substantiate the health claims of food by-products. Technological advances are needed to improve the stability and bioavailability of bioactive compounds. Implementing safety assessments and regulatory frameworks for functional food derived from food waste is crucial. This is essential for maximizing the potential of food waste, reducing carbon footprint, and improving human health.

An integrated bioinformatics analysis reveals IRF8 as a critical biomarker for immune infiltration in atherosclerosis advance

Atherosclerosis, a lipid-driven chronic inflammatory disorder, is a significant global health concern associated with high rates of morbidity and mortality, imposing a substantial societal burden. The purpose of this study is to investigate the possible molecular mechanisms of atherosclerosis and identify potential therapeutic targets. We conducted an integrated bioinformatics analysis using data from peripheral blood mononuclear cell and TISSUE databases obtained from the Gene Expression Omnibus, to identify key genes associated with the progression of atherosclerosis. Here, IRF8 was found to be a key gene in atherosclerosis patients. Silencing IRF8 with small interfering RNA reduced inflammation in endothelial cells. This suggests IRF8 is a crucial biomarker for immune infiltration in atherosclerosis advance.

Ovotransferrin, an alternative and potential protein for diverse food and nutritional applications

Ovotransferrin(OVT)is a protein found in many types of egg white and has a wide range of functional properties. It has 50% homology with human/bovine lactoferrin, and is expected to be one of the most important alternative proteins for use in food and nutritional applications. This paper mainly reviews the structural characteristics and chemical properties of OVT, as well as its extraction and purification methods. It also systematically describes the various biological activities of OVT and its applications in food and medical industries. The challenges and limitations in the research of OVT were suggested. This review recommends some possible methods such as nanoparticle carriers and microencapsulation to improve the bioavailability and stability of OVT. In addition, this review highlights several strategies to overcome the limitations of OVT in terms of preparation and purification. This review systematically summarizes the recent advances in OVT and will provide guidance for the its development for food and nutritional applications.

Food-Derived Up-Regulators and Activators of Angiotensin Converting Enzyme 2: A Review

Angiotensin-converting enzyme 2 (ACE2) is a key enzyme in the renin-angiotensin system (RAS), also serving as an amino acid transporter and a receptor for certain coronaviruses. Its primary role is to protect the cardiovascular system via the ACE2/Ang (1-7)/MasR cascade. Given the critical roles of ACE2 in regulating numerous physiological functions, molecules that can upregulate or activate ACE2 show vast therapeutic value. There are only a few ACE2 activators that have been reported, a wide range of molecules, including food-derived compounds, have been reported as ACE2 up-regulators. Effective doses of bioactive peptides range from 10 to 50 mg/kg body weight (BW)/day when orally administered for 1 to 7 weeks. Protein hydrolysates require higher doses at 1000 mg/kg BW/day for 20 days. Phytochemicals and vitamins are effective at doses typically ranging from 10 to 200 mg/kg BW/day for 3 days to 6 months, while Traditional Chinese Medicine requires doses of 1.25 to 12.96 g/kg BW/day for 4 to 8 weeks. ACE2 activation is linked to its hinge-bending region, while upregulation involves various signaling pathways, transcription factors, and epigenetic modulators. Future studies are expected to explore novel roles of ACE2 activators or up-regulators in disease treatments and translate the discovery to bedside applications.

Albumen and Yolk Plasma Peptidomics for the Identification and Quantitation of Bioactive Molecules and the Quality Control of Hen Egg Products

Hen eggs and the corresponding food products are essential components of human diet. In addition to supplying basic nutrients, they contain functional peptides that are released in vivo within the intact raw material following physiological proteolytic events affecting specific proteins or derive from technological processing of albumen and yolk fractions as a result of the dedicated use of proteases from plant and microbial sources. Besides their potential importance for functional applications, peptides released under physiological conditions in intact egg can be used as markers of product storage and deterioration. Therefore, characterization and quantitation of peptides in egg and egg-derived products can be used to implement evaluation of potential bioactivities as well as to assess food product qualitative characteristics. Here, we provide dedicated information on extraction, identification, and quantitative analysis of peptides from albumen and yolk plasma; nano-liquid chromatography-mass spectrometry combined with bioinformatic analysis of resulting raw data by different software tools allowed to assign molecules based on database searching and to evaluate their relative quantity in different samples.

Egg white protein hydrolysate decreased blood pressure via the competing endogenous RNA regulatory networks in female spontaneously hypertensive rats

Despite numerous studies having reported the effects and mechanisms of antihypertensive peptides including peptides derived from egg white proteins, the role of peptides in a female hypertensive animal model is unknown. On the other hand, the role of epigenetic modulation by peptide treatment has rarely been investigated. This study sought to investigate the effect of egg white protein hydrolysate (EWH) in female spontaneously hypertensive rats (SHRs) as well as to explore the underlying mechanisms from the perspectives of the transcriptome and the profiles of non-coding RNAs. Young (12-14-week-old) female SHRs were orally administered 250 mg per kg body weight (low-dose) or 1000 mg per kg body weight (high-dose) EWH daily for 10 weeks. The blood pressure of the rats was monitored weekly. The mRNA and non-coding RNAs (miRNA, lncRNA, and circRNA) in the aorta were profiled by the high-throughput RNA-seq technique. Differentially expressed (DE) RNAs in the aorta were identified for the construction of the competing endogenous RNA (ceRNA) networks and key molecules were validated by qRT-PCR. The treatment of the high-dose EWH showed a significant effect on reducing blood pressure in female SHRs. Bioinformatic analyses revealed 813, 90, 347 and 869 DE-mRNAs, DE-miRNAs, DE-lncRNAs and DE-circRNAs, respectively. The CNTN5-LncRNA-XR_001835895.1-miR-384-5p was identified as the central network which was validated in the aorta and circulation of female SHRs. The results from this study demonstrated that the treatment with EWH reduced blood pressure via regulating the ceRNA networks in female SHRs, which provided novel insights into the mechanisms of food protein-derived antihypertensive peptides.

Interaction mechanism of egg derived peptides RVPSL and QIGLF with dipalmitoyl phosphatidylcholine membrane: microcalorimetric and molecular dynamics simulation studies

BACKGROUND

Egg-derived peptides are becoming increasingly popular due to their biological activity and non-toxic effects. The egg-derived peptides Arg-Val-Pro-Ser-Leu (RVPSL) and Gln-Ile-Gly-Leu-Phe (QIGLF) display strong angiotensin-converting enzyme inhibitory activity and they can be taken up by intestinal epithelial cells. The interaction of the egg-derived peptides RVPSL and QIGLF with the membrane remains unclear.

RESULTS

The position and structure of the peptides in the membrane were calculated. The maximum density values of RVPSL and QIGLF were 2.27 and 1.22 nm from the center of the 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) membrane, respectively, indicating that peptides penetrated the membrane-water interface and were embedded in the membrane. The interaction of RVPSL and QIGLF with the DPPC membrane did not affect the average area per lipid or the lipid sequence parameters. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between the peptide RVPSL with the DPPC membrane were 17.91 kJ mol-1 , -17.63 kJ mol-1 , 187.5 J mol-1 ·k-1 , respectively. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between peptide QIGLF with DPPC membrane were 17.10 kJ mol-1 , -17.12 kJ mol-1 , 114.8 J mol-1 ·k-1 , respectively.

CONCLUSION

The results indicated that the binding of peptides RVPSL and QIGLF to DPPC is an endothermic, spontaneous, and entropy-driven reaction. The results of the study are relevant to the problem of the low bioavailability of bioactive peptides (BP). © 2023 Society of Chemical Industry.

Identification and Screening of Potential ACE2 Activating Peptides from Soybean Protein Isolate Hydrolysate against Ang II-Induced Endothelial Dysfunction

Angiotensin-converting enzyme 2 (ACE2) is a counterregulator against ACE by converting angiotensin II (Ang II) to Ang-(1-7), and its down-regulation leads to endothelial dysfunction in the vascular system. In the present study, we investigated the effects of soybean protein isolate hydrolysate (SPIH) on Ang II-induced endothelial dysfunction with its underlying mechanisms via ACE2 activation in human umbilical vein endothelial cells (HUVECs). We further screened potential ACE2 activating peptides by peptidomics analysis combined with bioinformatics tools. Results showed that SPIH remarkably attenuated Ang II-induced cell migration from 129 to 92%, decreased the ROS level from 2.22-fold to 1.45-fold, and increased NO concentration from 31.4 ± 0.7 to 43.7 ± 0.1 μM in HUVECs. However, these beneficial effects were reversed by ACE2 inhibitor MLN-4760 to a certain extent, indicating the modulation of ACE2. Further results revealed that SPIH (1 mg/mL) significantly increased the expression and activity of ACE2 and two novel ACE2 activating peptides with different mechanisms were explored from SPIH. IVPQ and IAVPT (50 μM) enhanced ACE2 activity, and only IVPQ (50 μM) increased ACE2 protein expression in HUVECs. These findings furthered our understanding of the antihypertensive mechanism of SPIH mediating the ACE2 activation on vascular endothelium.

IRW (Ile-Arg-Trp) Alleviates DSS-Induced Intestinal Injury by Remodeling Gut Microbiota and Regulating Fecal SCFA Levels

Inflammatory bowel disease (IBD) is a chronic disease of unknown etiology with a progressive and destructive course and an increasing incidence worldwide. Dietary peptides have a variety of biological functions and are effective anti-inflammatories and antioxidants, making them a prospective class of material for treating intestinal inflammation. Our study investigated the association between Ile-Arg-Trp (IRW), a dietary oligopeptide, and intestinal microbial changes during the relief of colitis using different concentrations of IRW. We found that IRW can significantly alleviate mouse colonic barrier damage caused by dextran sulphate sodium salt (DSS) and promote intestinal health. The results of microbial community composition showed that the relative abundance of Bacillota and Lactobacillus in the gut microbiota at different concentrations of IRW was significantly increased and that the abundance of Bacteroides was suppressed. Surprisingly, the relative abundance of Odoribacter also received regulation by IRW concentration and had a positive correlation with acetic acid. IRW at 0.02 mg/mL and 0.04 mg/mL significantly altered the abundance of Bacillota, Odoribacter, and Lactobacillus.

Egg White Protein Ovotransferrin-Derived IRW (Ile-Arg-Trp) Inhibits LPS-Induced Barrier Integrity Dysfunction and Inflammation in Caco-2 Cells

Tripeptide IRW derived from egg ovotransferrin was initially identified to be an inhibitor of angiotensin-converting enzyme. Later, IRW has been shown to possess various bioactivities, including anti-inflammatory activity and the ability to suppress colitis development. Nevertheless, its role in protecting intestinal barrier integrity has not been reported. This study aims to investigate the effect of IRW on inhibiting intestinal barrier dysfunction and inflammation in lipopolysaccharide (LPS)-treated Caco-2 cells. Pretreatment with IRW could mitigate the LPS-induced reduction of transepithelial electronic resistance values and decrease the paracellular permeation of differentiated Caco-2 cell monolayers. Meanwhile, IRW restored the expression level and cell surface distribution of the tight junction protein occludin. Furthermore, IRW showed LPS-neutralizing activity and could significantly inhibit LPS-induced activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. In conclusion, our study demonstrated the ability of IRW to prevent LPS-induced intestinal barrier dysfunction and prohibit inflammatory responses.

Potential antihypertensive mechanism of egg white-derived peptide QIGLF revealed by proteomic analysis

Previous work has shown that egg white-derived peptide QIGLF has significant in vivo antihypertensive activity. This study aimed to clarify the antihypertensive mechanisms of QIGLF on spontaneously hypertensive rats (SHRs) by a serum proteomic approach. Here, the tandem mass tag (TMT) quantitative proteomic was performed to discover serum protein changes in SHRs with QIGLF. As a result, SHRs with 4 weeks of QIGLF treatment have distinct serum protein expression profiles by principal component and Pearson's correlation coefficient analysis. Based on Gene Ontology (GO) annotation, oxygen transport and organelle fusion were found to be a regulated major biological process. Besides, aldosterone regulated sodium reabsorption, mitophagy, gap junction, and tight junction were significantly regulated based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. QIGLF might exert antihypertensive effects in the SHRs by inhibiting Na+ reabsorption and oxidative stress, restoring gap junction and tight junction.

Recent findings on the cellular and molecular mechanisms of action of novel food-derived antihypertensive peptides

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Hypertension has remained a silent-killer.

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Novel peptides recently isolated from food proteins.

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Molecular mechanism of blood pressure-lowering: renin and ACE-inhibition, and beyond.

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Proposed molecular mechanisms for future research.

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Novel peptides are excellent candidates for nutraceutical development.

Hypertension impacts negatively on the quality of life of sufferers, and complications associated with uncontrolled hypertension are life-threatening. Hence, many research efforts are exploring the antihypertensive properties of bioactive peptides derived from food proteins using in vitro ACE-inhibitory assay, experimentally-induced and spontaneous hypertensive rats, normotensive and hypertensive human models. In this study, the cellular and molecular mechanisms of blood pressure-lowering properties of novel peptides reported in recent studies (2015-July 30, 2021) were discussed. In addition to common mechanisms such as the inhibition of angiotensin I-converting enzyme (ACE) and renin activities, recently recognized mechanisms through which bioactive peptides exert their antihypertensive properties including the induction of vasodilation via upregulation of cyclo-oxygenase (COX) and prostaglandin receptor and endothelial nitric oxide synthase expression and L-type Ca²⁺ channel blockade were presented. Similarly, emerging mechanisms of blood pressure-lowering by bioactive peptides such as modulation of inflammation (TNF-α, and other cytokines signaling), oxidative stress (Keap-1/Nrf2/ARE/HO-1 and related signaling pathways), PPAR-γ/caspase3/MAPK signaling pathways and inhibition of lipid accumulation were discussed. The review also highlighted factors that influence the antihypertensive properties of peptides such as method of hydrolysis (type and number of enzymes, and chemical used for hydrolysis, and microbial fermentation), and amino acid sequence and chain length of peptides.

Antioxidant Stress and Anti-Inflammatory Activities of Egg White Proteins and Their Derived Peptides: A Review

Oxidative stress and chronic inflammation are the common pathological bases of chronic diseases such as atherosclerosis, cancer, and cardiovascular diseases, but most of the treatment drugs for chronic diseases have side effects. There is an increasing interest to identify food-derived bioactive compounds that can mitigate the pathological pathways associated with oxidative stress and chronic inflammation. Egg white contain a variety of biologically active proteins, many of which have antioxidant and anti-inflammatory activities and usually show better activity after enzymatic hydrolysis. This review covers the antioxidative stress and anti-inflammatory activities of egg white proteins and their derived peptides and clarifies their mechanism of action in vivo and in vitro. In addition, the link between oxidative stress and inflammation as well as their markers are reviewed. It suggests the potential application of egg white proteins and their derived peptides and puts forward further research prospects.

Role of ACE2-Ang (1-7)-Mas axis in post-COVID-19 complications and its dietary modulation

Severe acute respiratory syndrome-coronavirus-2 (COVID-19) virus uses Angiotensin-Converting Enzyme 2 (ACE2) as a gateway for their entry into the human body. The ACE2 with cleaved products have emerged as major contributing factors to multiple physiological functions and pathogenic complications leading to the clinical consequences of the COVID-19 infection Decreased ACE2 expression restricts the viral entry into the human cells and reduces the viral load. COVID-19 infection reduces the ACE2 expression and induces post-COVID-19 complications like pneumonia and lung injury. The modulation of the ACE2-Ang (1–7)-Mas (AAM) axis is also being explored as a modality to treat post-COVID-19 complications. Evidence indicates that specific food components may modulate the AAM axis. The variations in the susceptibility to COVID-19 infection and the post-COVID its complications are being correlated with varied dietary habits. Some of the food substances have emerged to have supportive roles in treating post-COVID-19 complications and are being considered as adjuvants to the COVID-19 therapy. It is possible that some of their active ingredients may emerge as the direct treatment for the COVID-19.

Effects of IQW and IRW on Inflammation and Gut Microbiota in ETEC-Induced Diarrhea

Methods

The mice were randomly distributed into four groups: (a) control (CTRL) group, (b) ETEC group, (c) IQW-ETEC group, and (d) IRW-ETEC group. Villus length and crypt depth were measured after hematoxylin and eosin staining. The inflammatory reaction was analyzed via inflammatory cytokines (i.e., TNF-α, IL-1β, IL-6, and IL-10) using the enzyme-linked immunosorbent assay (ELISA). The microbiota in the colon was sequenced using 16S ribosomal RNA.

Results

The villus length decreased, the crypt depth decreased, and the expression of inflammatory cytokines (i.e., TNF-α, IL-1β, IL-6, and IL-10) increased due to ETEC. In the IRW-ETEC and IQW-ETEC groups, the Shannon index decreased (P < 0.05). IQW and IRW increased the abundance of Firmicutes, Proteobacteria, Clostridiales, Lachnospiraceae, and Alloprevotella; contrastingly, it decreased the abundance of Epsilonproteobacteria, Erysipelotrichales, Prevotellaceae, and Flavobacteriaceae compared to the ETEC group (P <0.05).

Conclusion

This study ascertained that the addition of IQW and IRW could alleviate jejunal inflammation and increase microbiota community diversity.

The Role of Bioactive Peptides in Diabetes and Obesity

Bioactive peptides are present in most soy products and eggs and have essential protective functions. Infection is a core feature of innate immunity that affects blood pressure and the glucose level, and ageing can be delayed by killing senescent cells. Food also encrypts bioactive peptides and protein sequences produced through proteolysis or food processing. Unique food protein fragments can improve human health and avoid metabolic diseases, inflammation, hypertension, obesity, and diabetes mellitus. This review focuses on drug targets and fundamental mechanisms of bioactive peptides on metabolic syndromes, namely obesity and type 2 diabetes, to provide new ideas and knowledge on the ability of bioactive peptide to control metabolic syndromes.

The Role of Bioactive Peptides in Diabetes and Obesity

Bioactive peptides are present in most soy products and eggs and have essential protective functions. Infection is a core feature of innate immunity that affects blood pressure and the glucose level, and ageing can be delayed by killing senescent cells. Food also encrypts bioactive peptides and protein sequences produced through proteolysis or food processing. Unique food protein fragments can improve human health and avoid metabolic diseases, inflammation, hypertension, obesity, and diabetes mellitus. This review focuses on drug targets and fundamental mechanisms of bioactive peptides on metabolic syndromes, namely obesity and type 2 diabetes, to provide new ideas and knowledge on the ability of bioactive peptide to control metabolic syndromes.

Enzymatic Hydrolysis of Ovotransferrin and the Functional Properties of Its Hydrolysates

Bioactive peptides have great potentials as nutraceutical and pharmaceutical agents that can improve human health. The objectives of this research were to produce functional peptides from ovotransferrin, a major egg white protein, using single enzyme treatments, and to analyze the properties of the hydrolysates produced. Lyophilized ovotransferrin was dissolved in distilled water at 20 mg/mL, treated with protease, elastase, papain, trypsin, or α-chymotrypsin at 1% (w/v) level of substrate, and incubated for 0–24 h at the optimal temperature of each enzyme (protease 55°C, papain 37°C, elastase 25°C, trypsin 37°C, α-chymotrypsin 37°C). The hydrolysates were tested for antioxidant, metal-chelating, and antimicrobial activities. Protease, papain, trypsin, and α-chymotrypsin hydrolyzed ovotransferrin relatively well after 3 h of incubation, but it took 24 h with elastase to reach a similar degree of hydrolysis. The hydrolysates obtained after 3 h of incubation with protease, papain, trypsin, α-chymotrypsin, and after 24 h with elastase were selected as the best products to analyze their functional properties. None of the hydrolysates exhibited antioxidant properties in the oil emulsion nor antimicrobial property at 20 mg/mL concentration. However, ovotransferrin with α-chymotrypsin and with elastase had higher Fe³⁺-chelating activities (1.06±0.88%, 1.25±0.24%) than the native ovotransferrin (0.46±0.60%). Overall, the results indicated that the single-enzyme treatments of ovotransferrin were not effective to produce peptides with antioxidant, antimicrobial, or Fe³⁺-chelating activity. Further research on the effects of enzyme combinations may be needed.

Legumes as Functional Food for Cardiovascular Disease

Legumes are an essential food source worldwide. Their high-quality proteins, complex carbohydrates, dietary fiber, and relatively low-fat content make these an important functional food. Known to possess a multitude of health benefits, legume consumption is associated with the prevention and treatment of cardiovascular diseases (CVD). Legume crude protein isolates and purified peptides possess many cardiopreventive properties. Here, we review selected economically valued legumes, their taxonomy and distribution, biochemical composition, and their protein components and the mechanism(s) of action associated with cardiovascular health. Most of the legume protein studies had shown upregulation of low-density lipoprotein (LDL) receptor leading to increased binding and uptake, in effect significantly reducing total lipid levels in the blood serum and liver. This is followed by decreased biosynthesis of cholesterol and fatty acids. To understand the relationship of identified genes from legume studies, we performed gene network analysis, pathway, and gene ontology (GO) enrichment. Results showed that the genes were functionally interrelated while enrichment and pathway analysis revealed involvement in lipid transport, fatty acid and triglyceride metabolic processes, and regulatory processes. This review is the first attempt to collate all known mechanisms of action of legume proteins associated with cardiovascular health. This also provides a snapshot of possible targets leading to systems-level approaches to further investigate the cardiometabolic potentials of legumes.

Natural Products Modulating Angiotensin Converting Enzyme 2 (ACE2) as Potential COVID-19 Therapies

The 2019 coronavirus disease (COVID-19) is a potentially fatal multisystemic infection caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Currently, viable therapeutic options that are cost effective, safe and readily available are desired, but lacking. Nevertheless, the pandemic is noticeably of lesser burden in African and Asian regions, where the use of traditional herbs predominates, with such relationship warranting a closer look at ethnomedicine. From a molecular viewpoint, the interaction of SARS-CoV-2 with angiotensin converting enzyme 2 (ACE2) is the crucial first phase of COVID-19 pathogenesis. Here, we review plants with medicinal properties which may be implicated in mitigation of viral invasion either via direct or indirect modulation of ACE2 activity to ameliorate COVID-19. Selected ethnomedicinal plants containing bioactive compounds which may prevent and mitigate the fusion and entry of the SARS-CoV-2 by modulating ACE2-associated up and downstream events are highlighted. Through further experimentation, these plants could be supported for ethnobotanical use and the phytomedicinal ligands could be potentially developed into single or combined preventive therapeutics for COVID-19. This will benefit researchers actively looking for solutions from plant bioresources and help lessen the burden of COVID-19 across the globe.

A comprehensive guide to the pharmacologic regulation of angiotensin converting enzyme 2 (ACE2), the SARS-CoV-2 entry receptor

The recent emergence of coronavirus disease-2019 (COVID-19) as a global pandemic has prompted scientists to address an urgent need for defining mechanisms of disease pathology and treatment. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent for COVID-19, employs angiotensin converting enzyme 2 (ACE2) as its primary target for cell surface attachment and likely entry into the host cell. Thus, understanding factors that may regulate the expression and function of ACE2 in the healthy and diseased body is critical for clinical intervention. Over 66% of all adults in the United States are currently using a prescription drug and while earlier findings have focused on possible upregulation of ACE2 expression through the use of renin angiotensin system (RAS) inhibitors, mounting evidence suggests that various other widely administered drugs used in the treatment of hypertension, heart failure, diabetes mellitus, hyperlipidemias, coagulation disorders, and pulmonary disease may also present a varied risk for COVID-19. Specifically, we summarize mechanisms on how heparin, statins, steroids and phytochemicals, besides their established therapeutic effects, may also interfere with SARS-CoV-2 viral entry into cells. We also describe evidence on the effect of several vitamins, phytochemicals, and naturally occurring compounds on ACE2 expression and activity in various tissues and disease models. This comprehensive review aims to provide a timely compendium on the potential impact of commonly prescribed drugs and pharmacologically active compounds on COVID-19 pathology and risk through regulation of ACE2 and RAS signaling.

Functional properties of ovotransferrin from chicken egg white and its derived peptides: a review

With emerging trends in the food and pharmaceutical industries, potential applications of egg-derived bioactive compounds were recognized. Ovotransferrin is a major egg white functional protein responsible for multiple bioactivities. The objectives of this review are to provide scientific evidence of the functional properties of chicken ovotransferrin and its derived peptides and to identify future research approaches and applications. Various easy, economical, and non-toxic methods have been reported to produce ovotransferrin with high yield and purity, and chemical and enzymatic approaches have been employed to release bioactive peptides. The native ovotransferrin is known to have antimicrobial, antioxidant, anticancer, and immunomodulatory activities. The peptides produced from ovotransferrin also are reported to have antioxidant, antimicrobial, antihypertensive, and anticancer properties. However, little or no application of these compounds in the food and pharmaceutical areas is available yet. Therefore, the practical application of OTF in nutraceutical and pharmaceutical areas are among the emerging areas of research.

Novel ACE Inhibitory Peptides Derived from Yeast Hydrolysates: Screening, Inhibition Mechanisms and Effects on HUVECs

The antihypertensive activity of yeast hydrolysate (YH) was confirmed in our previous study. However, the critical peptides in YH and the underlying mechanisms have not been fully elucidated. This study aimed to explore the angiotensin-converting enzyme (ACE) inhibitory peptides in YH and illustrate their molecular and cellular mechanisms. The potential of YH-derived peptides was evaluated by in silico methods, followed by in vitro verification. A new competitive ACE inhibitory peptide, VIPVPFF (V7), with an IC₅₀ value of 10.27 μM, was screened. YH and V7 increased the nitric oxide (NO) levels, upregulated GUCY1A1 gene expression (approximately 15-fold), and functioned in several hypertension-related pathways in human umbilical vein endothelial cells (HUVECs). This study revealed the antihypertensive mechanisms of YH and V7, laying down a theoretical basis for their application.

Tripeptide IRW Upregulates NAMPT Protein Levels in Cells and Obese C57BL/6J Mice

Nicotinamide adenine dinucleotide (NAD⁺) plays a vital role in cellular processes that govern human health and disease. Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme in NAD⁺ biosynthesis. Thus, boosting NAD⁺ level via an increase in NAMPT levels is an attractive approach for countering the effects of aging and metabolic disease. This study aimed to establish IRW (Ile-Arg-Trp), a small tripeptide derived from ovotransferrin, as a booster of NAMPT levels. Treatment of muscle (L6) cells with IRW increased intracellular NAMPT protein levels (2.2-fold, p < 0.05) and boosted NAD⁺ (p < 0.01). Both immunoprecipitation and recombinant NAMPT assays indicated the possible NAMPT-activating ability of IRW (p < 0.01). Similarly, IRW increased NAMPT mRNA and protein levels in the liver (2.6-fold, p < 0.01) and muscle tissues (2.3-fold, p < 0.05) of C57BL/6J mice fed with a high-fat diet (HFD). A significantly increased level of circulating NAD⁺ was also observed following IRW treatment (4.7 fold, p < 0.0001). Dosing of Drosophila melanogaster with IRW elevated both D-NAAM (fly NAMPT) and NAD⁺ in vivo (p < 0.05). However, IRW treatment did not boost NAMPT levels in SIRT1 KO cells, indicating a possible SIRT1 dependency for the pharmacological effect. Overall, these data indicate that IRW is a novel small peptide booster of the NAMPT pool.

Bioactive Peptides and Hydrolysates from Egg Proteins as a New Tool for Protection Against Cardiovascular Problems

The aim of the present work is to review the potential beneficial effects of dietary supplementation with bioactive egg protein hydrolysates or peptides on cardiometabolic changes associated with oxidative stress. The development of nutritionally improved food products designed to address specific health concerns is of particular interest because many bioactive food compounds can be potentially useful in various physiological functions such as for reducing oxidative stress. The results presented suggest that egg hydrolysates or derived peptides could be included in the diet to prevent and/or reduce some cardiometabolic complications associated with oxidative stress-related diseases.

Purification and identification of novel ACE inhibitory and ACE2 upregulating peptides from spent hen muscle proteins

The study explored the use of spent hen, a major egg industry byproduct, as the starting material for preparing antihypertensive peptides. While previous studies were focused mainly on ACE inhibitory (ACEi) peptides, this work also studied peptides with ACE2 upregulating (ACE2u) activity, an emerging target for treating hypertension. Spent hen muscle protein hydrolysate prepared by thermoase (SPH-T) exhibited both ACEi and ACE2u activities. After ultrafiltration and chromatographic fractionation, five potent ACEi peptides, VRP, LKY, VRY, KYKA, and LKYKA, with IC₅₀ values of 0.034-5.77 μg/mL, respectively, and four ACE2u peptides, VKW, VHPKESF, VVHPKESF and VAQWRTKYETDAIQRTEELEEAKKK, which increased ACE2 expression by 0.52-0.84 folds, respectively, were identified; VKW also showed ACEi activity. All peptides, except for VRP, are susceptible to degradation during the simulated gastrointestinal digestion. Our study supports the potential use of spent hens as antihypertensive functional food ingredients and nutraceuticals.

A Novel Angiotensin Converting Enzyme 2 (ACE2) Activating Peptide: A Reflection of 10 Years of Research on a Small Peptide Ile-Arg-Trp (IRW)

IRW (Ile-Arg-Trp) was identified as an inhibitor of angiotensin converting enzyme (ACE) from egg white protein ovotransferrin through an integrated in silico digestion and quantitative structure and activity relationship prediction in 2011. Oral administration of IRW to spontaneously hypertensive rats (SHRs) can significantly reduce blood pressure, via upregulation of ACE2, but not through the inhibition of ACE. ACE2 converts Ang II into Ang (1-7), thus lowering blood pressure via Mas receptor (MasR); coinfusion of Mas receptor antagonist A779 and IRW in SHRs abolished blood pressure-lowering effect of IRW, supporting a key role of ACE2/Ang (1-7)/MasR axis. Our ongoing study further established new roles of IRW as an antioxidant, an anti-inflammatory agent, an insulin sensitizer, and a bone cell anabolic. Future studies are warranted to understand the unique structure features of this peptide, its mechanisms of action at various targets, its bioavailability and metabolism, and its possible roles toward COVID-19.

Spent Hen Protein Hydrolysate with Good Gastrointestinal Stability and Permeability in Caco-2 Cells Shows Antihypertensive Activity in SHR

Spent hens are a major byproduct of the egg industry but are rich in muscle proteins that can be enzymatically transformed into bioactive peptides. The present study aimed to develop a spent hen muscle protein hydrolysate (SPH) with antihypertensive activity. Spent hen muscle proteins were hydrolyzed by nine enzymes, either individually or in combination; 18 SPHs were assessed initially for their in vitro angiotensin-converting enzyme (ACE) inhibitory activity, and three SPHs, prepared by Protex 26L (SPH-26L), pepsin (SPH-P), and thermoase (SPH-T), showed promising activity and peptide yield. These three hydrolysates were further assessed for their angiotensin-converting enzyme 2 (ACE2) upregulating, antioxidant, and anti-inflammatory activities; only SPH-T upregulated ACE2 expression, while all three SPHs showed antioxidant and anti-inflammatory activities. During simulated gastrointestinal digestion, ACE2 upregulating, ACE inhibitory and antioxidant activities of SPH-T were not affected, but those of SPH-26L and SPH-P were reduced. ACE inhibitory activity of gastrointestinal-digested SPH-T was not affected after the permeability study in Caco-2 cells, while ACE2 upregulating, antioxidant and anti-inflammatory activities were improved; nine novel peptides with five–eight amino acid residues were identified from the Caco-2 permeate. Among these three hydrolysates, only SPH-T reduced blood pressure significantly when given orally at a daily dose of 1000 mg/kg body weight to spontaneously hypertensive rats. SPH-T can be developed into a promising functional food ingredient against hypertension, contributing to a more sustainable utilization for spent hens while generating extra revenue for the egg industry.

Towards treatment planning of COVID-19: Rationale and hypothesis for the use of multiple immunosuppressive agents: Anti-antibodies, immunoglobulins, and corticosteroids

The novel coronavirus, SARS-CoV2, can cause a potentially fatal disease, COVID-19, in humans. Here, we will provide an overview of therapeutic options for COVID-19. Plasma from patients recovered from COVID-19 that contains antibodies against SARS-CoV2 has shown promising results in patients with severe COVID-19. Also, IVIG, combined with moderate-dose of corticosteroids, might improve patient outcomes. Evidence links COVID-19 to variable degrees of inflammation. Studies show that the use of corticosteroids might accelerate recovery from COVID-19. There are, however, no controlled clinical trials that show whether the use of corticosteroids can reduce COVID-19-related death. Also, the pro-inflammatory cytokine IL6 is the best-documented cytokine in COVID-19 correlated with severity, criticality, viral load, and prognosis of patients with COVID-19. Tocilizumab, a monoclonal antibody against IL6, could confer clinical benefit in patients with high IL6 levels. Essential elements that process SARS-CoV2 cell entry and specific characteristics that allow SARS-CoV2 to escape the immune system have the potential as targets for COVID-19 therapy.

The ACE2/Ang (1-7)/MasR axis as an emerging target for antihypertensive peptides

Food protein-derived bioactive peptides, particularly antihypertensive peptides, are important constituents of functional foods or nutraceuticals. Most antihypertensive are identified as the inhibitors of angiotensin converting enzyme (ACE), a key enzyme responsible for the generation of angiotensin II (Ang II), which is a vasoconstricting peptide. Hence, ACE has long been used as a universal target to identify antihypertensive peptides. Angiotensin converting enzyme 2 (ACE2), is a homolog of ACE but uses Ang II as its key substrate to produce angiotensin (1-7), exerting vasodilatory activity via the mas receptor (MasR). Therefore, ACE2 functions in the opposite way as ACE and is an emerging novel target for cardiovascular therapy. The potential of food protein-derived bioactive peptides in targeting ACE2 has been rarely explored. While, recently we found that IRW, an egg white ovotransferrin-derived antihypertensive peptide, reduced blood pressure in spontaneously hypertensive rats via the ACE2/Ang (1-7)/MasR axis, indicating a new mechanism of food protein-derived bioactive peptides in reducing blood pressure. The objectives of this review are to summarize the functions of the ACE2/Ang (1-7)/MasR axis and to examine its potential roles in the actions of food protein-derived antihypertensive peptides. The interaction between antihypertensive peptides and the ACE2/Ang (1-7)/MasR axis will also be discussed.

Regulatory Effects of a Pea-Derived Peptide Leu-Arg-Trp (LRW) on Dysfunction of Rat Aortic Vascular Smooth Muscle Cells against Angiotensin II Stimulation

Vascular oxidative stress, inflammatory response, and proliferation are crucial mediators of vascular dysfunction which contribute to the pathology of hypertension. A tripeptide, LRW (Leu-Arg-Trp), was characterized from pea protein legumin, and its previously studied isomer IRW (Ile-Arg-Trp) was reported to exhibit antihypertensive activity via activation of angiotensin-converting enzyme 2. The objective of the current study was to explore the effects of LRW on vascular stress in vascular smooth muscle cells (VSMCs) under angiotensin II (Ang II)-induced cellular stress. LRW treatment could decrease Ang II-triggered superoxide production, inflammation, and proliferation in VSMCs. The abovementioned advantageous effects appeared to involve the upregulation of the ACE2-Ang-(1-7)-MasR axis and modulation of the nuclear factor-κB pathway. These findings specified the prospective role of LRW as a functional food ingredient or nutraceutical in the prevention of cardiovascular diseases, particularly hypertension and vascular damage.

Perspectives on the Potential Benefits of Antihypertensive Peptides towards Metabolic Syndrome

In addition to the regulation of blood pressure, the renin-angiotensin system (RAS) also plays a key role in the onset and development of insulin resistance, which is central to metabolic syndrome (MetS). Due to the interplay between RAS and insulin resistance, antihypertensive compounds may exert beneficial effects in the management of MetS. Food-derived bioactive peptides with RAS blocking properties can potentially improve adipose tissue dysfunction, glucose intolerance, and insulin resistance involved in the pathogenesis of MetS. This review discusses the pathophysiology of hypertension and the association between RAS and pathogenesis of the MetS. The effects of bioactive peptides with RAS modulating effects on other components of the MetS are discussed. While the in vivo reports on the effectiveness of antihypertensive peptides against MetS are encouraging, the exact mechanism by which these peptides infer their effects on glucose and lipid handling is mostly unknown. Therefore, careful design of experiments along with standardized physiological models to study the effect of antihypertensive peptides on insulin resistance and obesity could help to clarify this relationship.

Biological Activities of Egg Yolk Lipids: A Review

As one of six dietary nutrients, lipid derived from different food matrices has been extensively studied and has an appropriate application in food, medicine, and cosmetic industry. Egg is a richly nutritive food, of which proteins and lipids possess excellent functional characteristics and biological activities. In recent years, egg yolk lipid has been successively separated and investigated, such as egg yolk oil, phospholipids, and fatty acids, which have anti-inflammatory activity, antioxidant activity, cardiovascular protection, and memory improvement, involving the regulation of cell function and physiological homeostatic balance. In this paper, the biological activities and underlying benefit of egg yolk lipids and fat-soluble components have been highlighted and summarized. Meanwhile, the quantitative data of egg yolk lipids needed to achieve any of the described biological effects and recommended concentrations relevant for dietary intake are reviewed. Finally, current challenges and crucial issues of high-efficiency utilization of egg yolk lipids are also discussed.

Egg White-Derived Antihypertensive Peptide IRW (Ile-Arg-Trp) Reduces Blood Pressure in Spontaneously Hypertensive Rats via the ACE2/Ang (1-7)/Mas Receptor Axis

Scope

It is found in the previous study that egg‐white‐derived antihypertensive peptide Ile‐Arg‐Trp (IRW) upregulated angiotensin converting enzyme 2 (ACE2) in spontaneously hypertensive rats (SHRs). The objective of this study is to evaluate the contribution of ACE2 activation by IRW to blood‐pressure‐lowering activity in vivo.

Methods and results

Adult male SHRs (13–15 week old) are assigned into four groups: 1) untreated with saline infusion; 2) IRW administration (15 mg per kg body weight) with saline infusion; 3) Mas receptor (MasR) antagonist A779 (48 µg per kg body weight per h) infusion; 4) A779 infusion and IRW. Animals are implanted with telemetry transmitter first, and then an osmotic pump filled with saline or A779 is implanted. A779/saline is infused for 7 days, continued with an additional 7 days of treatments. Results indicate that blocking MasR abolished the blood‐pressure‐lowering effect of IRW. Akt/eNOS signaling in aorta is upregulated by IRW treatment but deactivated by A779 infusion. Circulating levels of interleukin 6 and monocyte chemoattractant protein 1, along with cyclooxygenase 2 in aorta are reduced by IRW but restored by A779 infusion.

Conclusion

IRW reduces blood pressure of SHR via the ACE2/Ang (1‐7)/MasR axis. Mechanisms pertaining to IRW as an ACE2 activator in vivo include enhanced endothelium‐dependent vasorelaxation and reduced vascular inflammation.

Rapeseed protein-derived peptides, LY, RALP, and GHS, modulates key enzymes and intermediate products of renin-angiotensin system pathway in spontaneously hypertensive rat

Rapeseed proteins are a rich source of bioactive peptides. LY, RALP and GHS were previously identified from rapeseed protein hydrolysates as potent ACE and renin inhibiting peptides. In this study, the rapeseed peptides were individually evaluated for their molecular mechanisms and regulatory effects on components of the renin-angiotensin system in spontaneously hypertensive rats (SHR), including the mRNA and/or protein levels of angiotensin-converting enzyme (ACE), renin, ACE2, angiotensin II and angiotensin-(1-7) in myocardial tissues. Oral administration of 30 mg peptides/kg body weight every 2 days for five weeks significantly decreased the systolic blood pressure and the myocardial mRNA and protein levels of ACE and renin in SHR. LY, RALP and GHS also increased the expression of ACE2, angiotensin-(1-7) and Mas receptor levels, which may have mediated their antihypertensive activity. Dipeptide LY also inhibited angiotensin II protein expression in the heart tissue. Taken together, the finding demonstrates the multi-target physiological effects of the rapeseed peptides, beyond ACE and renin inhibition, which enhances knowledge of the antihypertensive mechanisms of food protein-derived peptides.

Egg White-Derived Tripeptide IRW (Ile-Arg-Trp) Is an Activator of Angiotensin Converting Enzyme 2

Angiotensin converting enzyme 2 (ACE2) plays beneficial roles in the renin angiotensin aldosterone system. Our previous studies indicated that egg white-derived antihypertensive peptide IRW (Ile-Arg-Trp) could upregulate ACE2 mRNA level in mesenteric artery of spontaneously hypertensive rats (SHRs), suggesting the potential of IRW as an in vivo ACE2 activator. In this study, the effects of IRW on activity and protein expression of ACE2 were investigated. Results indicated that IRW activated human recombinant ACE2 with an EC₅₀ value of 7.24 × 10^-5 M. In rat aortic vascular smooth muscle cell line A7r5 cells, IRW treatment (50 μM) significantly increased the expression and activity of ACE2. Oral administration of IRW to SHRs upregulated ACE2 protein levels in kidney and aorta. Molecular docking study suggested that IRW might activate ACE2 through interaction with the subdomain I near the active site through hydrogen bonds. Overall, this study established IRW as the first food-derived ACE2 activating peptide.

Egg white hydrolysate and peptide reverse insulin resistance associated with tumor necrosis factor-α (TNF-α) stimulated mitogen-activated protein kinase (MAPK) pathway in skeletal muscle cells

Purpose

Excessive formation of tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine, has been implicated in the development of insulin resistance in obesity and type-2 diabetes. In skeletal muscle, chronic exposure to TNF-α impairs insulin-stimulated glucose uptake and insulin signaling. The aim of this study is to investigate the effects of enzymatic egg white hydrolysate (EWH) and its responsible peptide, IRW, on TNF-α-induced insulin resistance and the underlying molecular mechanisms using rat skeletal muscle cells (L6 cells).

Methods

Insulin resistance was induced by treating L6 cells with 5 ng/ml TNF-α for 24 h. Effects of EWH and IRW on glucose uptake were detected by glucose uptake assay, glucose transporter 4 (GLUT4) translocation by immunofluorescence, and western blot, while insulin-signaling pathway and mitogen-activated protein kinase (MAPK) pathway were investigated using western blot.

Results

Adding both EWH and IRW significantly improved glucose uptake in TNF-α-treated cells, increased activation of insulin receptor substrate (IRS-1) tyrosine residue and protein kinase B (Akt), whereas decreased activation of IRS-1 serine residue. In addition, TNF-α-induced activation of p38-mitogen-activated protein kinase (p38) and c-Jun N-terminal kinases (JNK) 1/2 were decreased by either EWH or IRW treatment.

Conclusion

EWH and IRW improve impaired insulin sensitivity by down-regulating the activation of p38 and JNK1/2 in TNF-α-treated skeletal muscle cells.

Molecular targets and mechanisms of bioactive peptides against metabolic syndromes

Bioactive peptides are present in all living organisms and have critical roles ranging from protection against infection as the key element of innate immunity, regulating blood pressure and glucose levels, to reducing signs of ageing by killing senescent cells. Bioactive peptides are also encrypted within food protein sequences that can be released during proteolysis or food processing. These specific food protein fragments are reported to have potential for improving human health and preventing metabolic diseases through their impact on inflammation, blood pressure, obesity, and type-2 diabetes. This review mainly focuses on the molecular targets and the underlying mechanisms of bioactive peptides against various metabolic syndromes including inflammation, high blood pressure, obesity, and type-2 diabetes, to provide new insights and perspectives on the potential of bioactive peptides for management of metabolic syndromes.

Egg White-Derived Antihypertensive Peptide IRW (Ile-Arg-Trp) Inhibits Angiotensin II-Stimulated Migration of Vascular Smooth Muscle Cells via Angiotensin Type I Receptor

Excessive proliferation, inflammation, oxidative stress, and migration induced by angiotensin II (Ang II), occurring in vascular smooth muscle cells (VSMCs) during vascular remodelling, are major pathogenesis of hypertension. Antihypertensive peptides derived from food proteins are promising alternatives in preventing/treating hypertension and associated complications. In addition to reducing high blood pressure in spontaneously hypertensive rats, egg white ovotransferrin-derived antihypertensive IRW (Ile-Arg-Trp) was shown to exert antiproliferative, antioxidant, and anti-inflammatory effects in A7r5 cells (a vascular smooth muscle cell line) against Ang II stimulation, further indicating its potential in retarding vascular remodelling. Since its regulatory role in migration of VSMC is unclear, the objective of this study was to evaluate the antimigrant activity of IRW in Ang II-stimulated A7r5 cells. It was found that IRW could downregulate matrix metallopeptidase 9 (MMP9) expression and inhibit migration of Ang II-stimulated A7r5 cells, which was associated with inactivation of p38/MAPK signaling. More importantly, the antimigrant activity of IRW in Ang II-stimulated A7r5 cells was dependent on angiotensin type I receptor (AT1R). Our study provided the first evidence that egg ovotransferrin-derived antihypertensive peptide IRW inhibited migration of VSMCs.