Ameliorative Effects of Peptide Phe-Leu-Ala-Pro on Acute Liver and Kidney Injury Caused by CCl4 via Attenuation of Oxidative Stress and Inflammation

Analysis of the liver-gut axis including metabolomics and intestinal flora to determine the protective effects of kiwifruit seed oil on CCl4-induced acute liver injury

The hepatoprotective effects of kiwifruit seed oil (KSO) were evaluated on acute liver injury (ALI) induced by carbon tetrachloride (CCl4) in vivo. Network pharmacology was used to predict active compounds and targets. Metabolomics and gut microbiota analyses were used to discover the activity mechanism of KSO. KSO improved the liver histological structure, significantly reduced serum proinflammatory cytokine levels, and increased liver antioxidant capacity. The metabolomics analysis showed that KSO may have hepatoprotective effects by controlling metabolites through its participation in signaling pathways like tryptophan metabolism, glycolysis/gluconeogenesis, galactose metabolism, and bile secretion. The gut microbiota analysis demonstrated that KSO improved the composition and quantity of the gut flora. Network pharmacological investigations demonstrated that KSO operated by altering Ptgs2, Nos2, Ppara, Pparg and Serpine1 mRNA levels. All evidence shows that KSO has a hepatoprotective effect, and the mechanism is connected to the regulation of metabolic disorders and intestinal flora.

Soybean-derived antihypertensive hydrolysates attenuate Ang II-induced renal damage by modulating MAPK and NF-κB signaling pathways

Hypertension-induced kidney injury is considered a vital consequence of long-term and uncontrolled hypertension, which is commonly associated with an excessive accumulation of angiotensin II (Ang II) from hyperactivated RAS. Antihypertensive peptides have a significant effect on blood pressure regulation, but few studies have focused on the ameliorative function of antihypertensive peptides on renal injury. This study explored the effects of soybean protein-derived hydrolysate (SPH) on SHR and Ang II-induced HK-2 cells. SPH significantly attenuated blood pressure and alleviated renal pathological injury in SHRs after oral gavage administration. According to the pathological results, the kidneys of SHRs showed inflammation and SPH attenuated inflammatory cell infiltration in the kidneys of SHRs. Immunohistochemical analysis further revealed that SPH inhibited MCP-1 expression and increased Nrf2 expression in the kidneys. An in vitro HK-2 cell model demonstrated that SPH exhibited optimal activity for reducing Ang II-induced inflammatory cytokines and ROS overproduction. Mechanistically, SPH was observed to regulate MAPK/JNK and NF-κB signaling pathways. These findings indicate that potent antihypertensive SPH significantly ameliorates hypertension-induced kidney damage.

Alpha-pinene alleviates CCl4-induced renal and testicular injury in rats by targeting oxidative stress, inflammation, and apoptosis

Objectives

Renal and testicular disorders are primarily associated with oxidative damage and inflammation. Here, alpha-pinene (a type of monoterpene) was investigated for its effect on oxidative/nitrosative stress and the expression of inflammatory and apoptotic factors in the kidneys and testes of rats treated with CCl4.

Materials and Methods

CCl4 was injected intraperitoneally (IP) at a dose of 2 ml/kg (twice a week for six weeks). Alpha-pinene (50 mg/kg/day, IP) was also treated during the same period.

Results

CCl4 increased the level of malondialdehyde (P<0.01 in the kidney and P<0.001 in the testis) and nitric oxide (P<0.001 in the kidney and P<0.01 in the testis) and decreased the levels of glutathione (P<0.05) in the kidneys and testicles of rats. CCl4 also reduced the catalase enzyme activity in the kidneys (P<0.05) but did not affect its activity in the testis. In addition, CCl4 enhanced the mRNA expression of TNF-α (P<0.01), nuclear factor-κB (P<0.05), and Bax (P<0.05 in the kidney and P<0.01 in the testis) and decreased the expression of Bcl-2 (P<0.05) in both organs. Alpha-pinene prevented all the mentioned changes, but it did not influence the expression of Bcl-2 in the kidneys of rats receiving CCl4.

Conclusion

Alpha-pinene may have the potential to prevent renal and testicular diseases by strengthening the antioxidant system in the kidneys and testis, and inhibiting oxidative/nitrosative stress, inflammation, and apoptosis caused by CCl4.

Peptides from Harpadon nehereus Bone Ameliorate Angiotensin II-Induced HUVEC Injury and Dysfunction through Activation of the AKT/eNOS and Nrf2 Pathway

Angiotensin II (Ang II)-induced vascular endothelial cell injury and dysfunction are important pathophysiological factors in the occurrence and development of hypertension. In this study, the amelioration effects of two peptides KA-8 (KLHDEEVA) and PG-7 (PSRILYG) from Harpadon nehereus bone on Ang II-induced damage and dysfunction in human umbilical vein endothelial cells (HUVECs) were investigated. The results showed that they could significantly decrease the reactive oxygen species (ROS) level and increase the activity of antioxidant enzymes in Ang II-induced HUVEC. Two peptides, especially PG-7, significantly upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, PG-7 significantly reduced the level of expression of endothelin-1(ET-1) and increased the phosphorylation level of phosphoinositide 3-kinase (PI3K), serine/threonine kinase (AKT), and nitric oxide synthase (eNOS). These results indicated that the two peptides, especially PG-7, can ameliorate angiotensin II-induced HUVEC injury and dysfunction through activation of the AKT/eNOS and Nrf2 pathway. Furthermore, PG-7 showed a stronger affinity with angiotensin-converting enzyme (ACE) and ACE inhibitory than KA-8. In conclusion, peptide PG-7 reveals potential in the prevention and treatment of hypertension.

Novel Ca-Chelating Peptides from Protein Hydrolysate of Antarctic Krill (Euphausia superba): Preparation, Characterization, and Calcium Absorption Efficiency in Caco-2 Cell Monolayer Model

Antarctic krill (Euphausia superba) is the world's largest resource of animal proteins and is thought to be a high-quality resource for future marine healthy foods and functional products. Therefore, Antarctic krill was degreased and separately hydrolyzed using flavourzyme, pepsin, papain, and alcalase. Protein hydrolysate (AKH) of Antarctic krill prepared by trypsin showed the highest Ca-chelating rate under the optimized chelating conditions: a pH of 8.0, reaction time of 50 min, temperature of 50 °C, and material/calcium ratio of 1:15. Subsequently, fourteen Ca-chelating peptides were isolated from APK by ultrafiltration and a series of chromatographic methods and identified as AK, EAR, AEA, VERG, VAS, GPK, SP, GPKG, APRGH, GVPG, LEPGP, LEKGA, FPPGR, and GEPG with molecular weights of 217.27, 374.40, 289.29, 459.50, 275.30, 300.36, 202.21, 357.41, 536.59, 328.37, 511.58, 516.60, 572.66, and 358.35 Da, respectively. Among fourteen Ca-chelating peptides, VERG presented the highest Ca-chelating ability. Ultraviolet spectrum (UV), Fourier Transform Infrared (FTIR), and scanning electron microscope (SEM) analysis indicated that the VERG-Ca chelate had a dense granular structure because the N-H, C=O and -COOH groups of VERG combined with Ca2+. Moreover, the VERG-Ca chelate is stable in gastrointestinal digestion and can significantly improve Ca transport in Caco-2 cell monolayer experiments, but phytate could significantly reduce the absorption of Ca derived from the VERG-Ca chelate. Therefore, Ca-chelating peptides from protein hydrolysate of Antarctic krill possess the potential to serve as a Ca supplement in developing healthy foods.

Antidiabetic Effect of Collagen Peptides from Harpadon nehereus Bones in Streptozotocin-Induced Diabetes Mice by Regulating Oxidative Stress and Glucose Metabolism

Oxidative stress and abnormal glucose metabolism are the important physiological mechanisms in the occurrence and development of diabetes. Antioxidant peptides have been reported to attenuate diabetes complications by regulating levels of oxidative stress, but few studies have focused on peptides from marine bone collagen. In this study, we prepared the peptides with a molecular weight of less than 1 kD (HNCP) by enzymolysis and ultrafiltration derived from Harpadon nehereus bone collagen. Furthermore, the effects of HNCP on blood glucose, blood lipid, liver structure and function, oxidative stress, and glucose metabolism were studied using HE staining, kit detection, and Western blotting experiment in streptozocin-induced type 1 diabetes mice. After the 240 mg/kg HNCP treatment, the levels of blood glucose, triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) in streptozotocin-induced diabetes mice decreased by 32.8%, 42.2%, and 43.2%, respectively, while the levels of serum insulin and hepatic glycogen increased by 142.0% and 96.4%, respectively. The antioxidant enzymes levels and liver function in the diabetic mice were markedly improved after HNCP intervention. In addition, the levels of nuclear factor E2-related factor 2 (Nrf2), glucokinase (GK), and phosphorylation of glycogen synthase kinase-3 (p-GSK3β) in the liver were markedly up-regulated after HNCP treatment, but the glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase1 (PEPCK1) were down-regulated. In conclusion, HNCP could attenuate oxidative stress, reduce blood glucose, and improve glycolipid metabolism in streptozocin-induced type 1 diabetes mice.