Isolation and characterization of anti-inflammatory peptides derived from whey protein

Digestion of whey peptide induces antioxidant and anti-inflammatory bioactivity on glial cells: Sequences identification and structural activity analysis

Whey derived peptides have shown potential activity improving brain function in pathological condition. However, there is little information about their mechanism of action on glial cells, which have important immune functions in brain. Astrocytes and microglia are essential in inflammatory and oxidative defense that take place in neurodegenerative disease. In this work we evaluate antioxidant and anti-inflammatory potential bioactivity of whey peptide in glial cells. Peptides were formed during simulated gastrointestinal digestion (Infogest protocol), and low molecular weight (<5kDA) peptides (WPHf) attenuated reactive oxygen species (ROS) production induced by hydrogen peroxide stimulus in both cells in dose-dependent manner. WPHf induced an increase in the antioxidant glutathione (GSH) content and prevented GSH reduction induced by lipopolysaccharides (LPS) stimulus in astrocytes cells in a cell specific form. An increase in cytokine mRNA expression (TNFα and IL6) and nitric oxide secretion induced by LPS was attenuated by WPHf pre-treatment in both cells. The inflammatory pathway was dependent on NFκB activation. Bioactive peptide ranking analysis showed positive correlation with hydrophobicity and negative correlation with high molecular weights. The sequence identification revealed 19 peptides cross-referred with bioactive database. Whey peptides were rich in leucine, valine and tyrosine in the C-terminal region and lysine in the N-terminal region. The anti-inflammatory and antioxidant potential of whey peptides were assessed in glia cells and its mechanisms of action were related, such as modulation of antioxidant enzymes and anti-inflammatory pathways. Features of the peptide structure, such as molecular size, hydrophobicity and types of amino acids present in the terminal region are associated to bioactivity.

Anti-inflammatory peptide therapeutics and the role of sulphur containing amino acids (cysteine and methionine) in inflammation suppression: A review

BACKGROUND

Inflammation serves as our body's immune response to combat infections, pathogens, viruses, and external stimuli. Inflammation can be classified into two types: acute inflammation and chronic inflammation. Non-steroidal anti-inflammatory medications (NSAIDs) are used to treat both acute and chronic inflammatory disorders. However, these treatments have various side effects such as reduced healing efficiency, peptic ulcers, gastrointestinal toxicities, etc. METHOD: This review assesses the potential of anti-inflammatory peptides (AIPs) derived from various natural sources, such as algae, fungi, plants, animals, and marine organisms. Focusing on peptides rich in cysteines and methionine, sulphur-containing amino acids known for their role in suppression of inflammation.

RESULT

Due to their varied biological activity, ability to penetrate cells, and low cytotoxicity, bioactive peptides have garnered interest as possible therapeutic agents. The utilisation of AIPs has shown great potential in the treatment of disorders associated with inflammation. AIPs can be obtained from diverse natural sources such as algae, fungi, plants, and animals. Cysteine and methionine are sulphur-containing amino acids that aid in the elimination of free radicals, hence assisting in the treatment of inflammatory diseases.

CONCLUSION

This review specifically examines several sources of AIPs including peptides that contain numerous cysteines and methionine. In addition, the biological characteristics of these amino acids and advancements in peptide delivery are also discussed.

In vitro assessment of biofunctional properties of Lactiplantibacillus plantarum strain Jb21-11 and the characterization of its exopolysaccharide

ABSTACT

The microbiota of traditional food provides a rich reservoir of biodiversity to find new strains with interesting features for novel functional food formulation. Therefore, this study aimed to investigate the biofunctional potential of the lactic acid bacteria (LAB) strain Jb21-11 isolated from Jben, a traditional Algerian fresh cheese. This isolate was selected out of a collection of 154 LAB based on its exopolysaccharide (EPS) phenotype and was preliminarily identified by polyphasic characterization as Lactiplantibacillus plantarum (previously known as Lactobacillus plantarum) and its biofunctional properties were then assessed in vitro. The tested strain demonstrated good resistance to gastric juice, acidity around pH 2, and 2% (v/v) bile salts, which are important characteristics for potential biofunctional LAB candidates. It also showed a good production of ropy EPS with 674 mg/L on MRS medium. However, this ability appears to compromise the adhesion of the strain to Caco-2 cells (less than 1%), which according to our results, seems not to be related to autoaggregation and hydrophobicity (44.88 ± 0.028% and 16.59 ± 0.012%). Furthermore, promising antimicrobial activity against three pathogenic bacteria (Escherichia coli, Staphylococcus aureus, and Salmonella) was detected probably due to antimicrobial metabolites excreted during fermentation process into the medium. Moreover, the strain L. plantarum Jb21-11 displayed a therapeutic functionality with both anti-inflammatory and immunomodulatory action using RAW 264.7 cells. The chemical features of the novel ropy Jb21-11-EPS were also investigated revealing the presence of three monosaccharides, namely, mannose, galactose, and glucose, with a molar ratio of 5.42:1.00:4.52 linked together by α- and β-glycosidic bonds, presenting a relatively high molecular weight of 1.08 × 105 Da of interest for a texturing potential. Therefore, the new producing EPS strain Jb21-11 is a promising candidate for use as an adjunct culture for improving the texture of functional food.

Food-derived peptides as novel therapeutic strategies for NLRP3 inflammasome-related diseases: a systematic review

NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3), a member of the nucleotide-binding domain (NOD) and leucine-rich repeat sequence (LRR) protein (NLR) family, plays an essential role in the inflammation initiation and inflammatory mediator secretion, and thus is also associated with many disease progressions. Food-derived bioactive peptides (FDBP) exhibit excellent anti-inflammatory activity in both in vivo and in vitro models. They are encrypted in plant, meat, and milk proteins and can be released under enzymatic hydrolysis or fermentation conditions, thereby hindering the progression of hyperuricemia, inflammatory bowel disease, chronic liver disease, neurological disorders, lung injury and periodontitis by inactivating the NLRP3. However, there is a lack of systematic review around FDBP, NLRP3, and NLRP3-related diseases. Therefore, this review summarized FDBP that exert inhibiting effects on NLRP3 inflammasome from different protein sources and detailed their preparation and purification methods. Additionally, this paper also compiled the possible inhibitory mechanisms of FDBP on NLRP3 inflammasomes and its regulatory role in NLRP3 inflammasome-related diseases. Finally, the progress of cutting-edge technologies, including nanoparticle, computer-aided screening strategy and recombinant DNA technology, in the acquisition or encapsulation of NLRP3 inhibitory FDBP was discussed. This review provides a scientific basis for understanding the anti-inflammatory mechanism of FDBP through the regulation of the NLRP3 inflammasome and also provides guidance for the development of therapeutic adjuvants or functional foods enriched with these FDBP.

Anti-inflammatory effect of two novel peptides derived from Binglangjiang buffalo whey protein in lipopolysaccharide-stimulated RAW264.7 macrophages

Whey protein hydrolysate from Binglangjiang buffalo, a unique genetic resource, has anti-inflammatory activity, but its anti-inflammatory composition and effects are unknown. The aim of this study was to investigate the anti-inflammatory peptides from Binglangjiang buffalo whey protein hydrolysate. A total of 1483 peptides were identified using LC-MS/MS, and 12 peptides were chosen for chemical synthesis using peptidomics, and then two novel anti-inflammatory peptides (DQPFFHYN (DN8) and YSPFSSFPR (YR9)) were screened out using LPS-stimulated RAW264.7 cells. The molecular weights of DN8 and YR9 with β-turn conformations were 1067.458 Da and 1087.52 Da, respectively, and showed a high in-vitro safety profile and thermal stability, but were intolerant to pepsin. Furthermore, ELISA and Western blot analysis indicated that peptides DN8 and YR9 significantly suppressed the secretion of pro-inflammatory cytokines NO, TNF-α, and IL-6 and the expression of mediators iNOS, TNF-α, and IL-6 in LPS-stimulated RAW264.7 cells. The study provides insights into the development of novel food-based anti-inflammatory nutritional supplements.

Macrophage-Immunomodulatory Actions of Bovine Whey Protein Isolate, Glycomacropeptide, and Their In Vitro and In Vivo Digests

Whey protein isolate (WPI) consists of an array of proteins and peptides obtained as a byproduct of the cheesemaking process. Research suggests that WPI, along with its peptides such as glycomacropeptide (GMP), possesses immunomodulatory properties. These properties hold potential for alleviating the adverse effects of inflammatory conditions such as inflammatory bowel disease. Although promising, the immunoregulatory properties of the digested forms of WPI and GMP-those most likely to interact with the gut immune system-remain under-investigated. To address this knowledge gap, the current study examined the effects of in vitro-digested WPI and GMP, in vivo-digested WPI, and undigested WPI and GMP on the secretion of pro-inflammatory cytokines (TNF-α and IL-1β) in lipopolysaccharide-stimulated macrophage-like cells. Our results indicate that digested WPI and GMP reduced the expression of TNF-α and IL-1β, two pro-inflammatory cytokines. Whole WPI had no effect on TNF-α but reduced IL-1β levels. In contrast, in vivo-digested WPI reduced TNF-α but increased IL-1β. Undigested GMP, on the other hand, increased the secretion of both cytokines. These results demonstrate that digestion greatly modifies the effects of WPI and GMP on macrophages and suggest that digested WPI and GMP could help mitigate gastrointestinal inflammation. Further clinical studies are necessary to determine the biological relevance of WPI and GMP digestion products within the gut and their capacity to influence gut inflammation.

Whey proteins as a functional food: Health effects, functional properties, and applications in food

Functional foods are defined as foods and ingredients that exhibit health benefits beyond their nutritional value. Research on functional foods is increasing rapidly as they may help prevent and manage some non-communicable diseases. Whey proteins are recognized as a high-quality nutrient source and known to contain some bioactive components. They are rich in essential amino acids such as cysteine, branched-chain amino acids such as leucine, valine, and isoleucine, and bioactive peptides. Whey proteins look promising as a potential functional food, given its antioxidant, anti-inflammatory, blood pressure lowering, anti-obesity, and appetite suppressing effects that is discussed in the literature. Whey proteins also show functional properties that play an essential role in food processing as an emulsifier, fat-replacer, gelling and encapsulating agent and are known to improve sensory and textural characteristics of food. This review focuses on the functional food aspects of whey proteins, associated health effects, and current food applications.

Whey protein hydrolysates improve high-fat-diet-induced obesity by modulating the brain-peripheral axis of GLP-1 through inhibition of DPP-4 function in mice

PURPOSE

Obesity is a growing global health concern. Recent literature indicates a prominent role of glucagon-like peptide-1 (GLP-1) in glucose metabolism and food intake. The synergistic action of GLP-1 in the gut and brain is responsible for its satiety-inducing effect, suggesting that upregulation of active GLP-1 levels could be an alternative strategy to combat obesity. Dipeptidyl peptidase-4 (DPP-4) is an exopeptidase known to inactivate GLP-1, suggesting that its inhibition could be a crucial strategy for effectively extending the half-life of endogenous GLP-1. Peptides derived from partial hydrolysis of dietary proteins are gaining traction due to their inhibitory activity on DPP-4.

METHODS

Whey protein hydrolysate from bovine milk (bmWPH) was produced using simulated in situ digestion, purified using RP-HPLC, and characterized for DPP-4 inhibition. The antiadipogenic and antiobesity activity of bmWPH was then studied in 3T3-L1 preadipocytes and high-fat diet-induced obesity (HFD) mice model, respectively.

RESULTS

The dose-dependent inhibitory effect of bmWPH on the catalytic activity of DPP-4 was observed. Additionally, bmWPH suppressed adipogenic transcription factors and DPP-4 protein levels, leading to a negative effect on preadipocyte differentiation. In an HFD mice model, co-administration of WPH for 20 weeks downregulated adipogenic transcription factors, resulting in a concomitant reduction in whole body weight and adipose tissues. Mice fed with bmWPH also showed a marked reduction in DPP-4 levels in WAT, liver, and serum. Furthermore, HFD mice fed with bmWPH exhibited increased serum and brain GLP levels, which led to a significant decrease in food intake.

CONCLUSION

In conclusion, bmWPH reduces body weight in HFD mice by suppressing appetite through GLP-1, a satiety-inducing hormone, in both the brain and peripheral circulation. This effect is achieved through modulation of both the catalytic and non-catalytic activity of DPP-4.

A Whey-Based Diet Can Ameliorate the Effects of LPS-Induced Growth Attenuation in Young Rats

Chronic inflammation in childhood is associated with impaired growth. In the current study, a lipopolysaccharide (LPS) model of inflammation in young rats was used to study the efficacy of whey-based as compared to soy-based diets to ameliorate growth attenuation. Young rats were injected with LPS and fed normal chow or diets containing whey or soy as the sole protein source during treatment, or during the recovery period in a separate set of experiments. The body and spleen weight, food consumption, humerus length, and EGP height and structure were evaluated. Inflammatory markers in the spleen and markers of differentiation in the EGP were assessed using qPCR. The LPS led to a significant increase in the spleen weight and a decrease in the EGP height. Whey, but not soy, protected the animals from both effects. In the recovery model, whey led to increased EGP height at both 3 and 16 d post treatment. The most affected region in the EGP was the hypertrophic zone (HZ), which was significantly shortened by the LPS treatment but enlarged by whey. In conclusion, LPS affected the spleen weight and EGP height and had a specific effect on the HZ. Nutrition with whey protein appeared to protect the rats from the LPS-induced growth attenuation.

Tandem mass tag-based quantitative proteomics analysis reveals the effects of the α-lactalbumin peptides GINY and DQW on lipid deposition and oxidative stress in HepG2 cells

The objective of this study was to investigate the mechanism by which the α-lactalbumin peptides Gly-Ile-Asn-Tyr (GINY) and Asp-Gln-Trp (DQW) ameliorate free fatty acid-induced lipid deposition in HepG2 cells. The results show that GINY and DQW reduced triglyceride, total cholesterol, and free fatty acid levels significantly in free fatty acid-treated HepG2 cells. Based on proteomic analysis, GINY and DQW alleviated lipid deposition and oxidative stress mainly through the peroxisome proliferator-activated receptor (PPAR) pathway, fatty acid metabolism, oxidative phosphorylation, and response to oxidative stress. In vitro experiments confirmed that GINY and DQW upregulated the mRNA and protein expression of fatty acid β-oxidation-related and oxidative stress-related genes, and downregulated the mRNA and protein expression of lipogenesis-related genes by activating peroxisome proliferator-activated receptor α (PPARα). Meanwhile, GINY and DQW reduced free fatty acid-induced lipid droplet accumulation and reactive oxygen species generation, and enhanced the mitochondrial membrane potential and ATP levels. Furthermore, GINY and DQW enhanced carnitine palmitoyl-transferase 1a (CPT-1a) and superoxide dismutase activities, and diminished acetyl-coenzyme A carboxylase 1 (ACC1) and fatty acid synthase (FASN) activities in a PPARα-dependent manner. Interestingly, GW6471 (a PPARα inhibitor) weakened the effects of GINY and DQW on the PPARα pathway. Hence, our findings suggest that GINY and DQW have the potential to alleviate nonalcoholic fatty liver disease by activating the PPARα pathway.

Identification, characterization and in vitro activity of hypoglycemic peptides in whey hydrolysates from rubing cheese by-product

The by-product of Chinese rubing cheese is rich in whey protein. Whey hydrolysates exhibit good hypoglycemic activity, but which specific peptide components are responsible for this effect have not yet been investigated. Herein, the α-glucosidase inhibitory activity of the ultrafiltered fraction (<3 kDa) of rubing cheese whey hydrolysates was evaluated with the inhibition rate of 37.89 %. In addition, peptide identification was conducted using LC-MS/MS, and three peptides YPVEPF, VPYPQ, and LPYPY were identified. Among these, YPVEPF had higher α-glucosidase inhibitory activity (IC₅₀ = 3.52 mg/mL) and interacted with α-glucosidase via hydrogen bonding and hydrophobic forces. YPVEPF was characterized as an amphipathic peptide rich in antiparallel (50.50 %) and random coil (35.20 %) structures, as well as showed good tolerance to gastrointestinal digestion and incubation under the temperature range of 20-80 °C. Notably, YPVEPF activity increased in the presence of Al³⁺ and Fe³⁺, as well as within the pH range of 2.0-6.0. Furthermore, YPVEPF had negligible hemolytic activity at a concentration of 1.0 mg/mL, no toxicity at concentrations below 0.5 mg/mL, and significantly promoted glucose consumption in HepG2 cells (p < 0.0001). Collectively, these findings indicate the potential of YPVEPF to be used as a novel hypoglycemic peptide in functional foods.

In vitro antioxidant and anti-inflammatory properties of Artocarpus altilis (Parkinson) Fosberg (seedless breadfruit) fruit pulp protein hydrolysates

Protein hydrolysates from dietary sources possess many physiological and biological properties. Artocarpus altilis is an evergreen multipurpose plant with many benefits. Therefore, this study evaluates in vitro antioxidant and anti-inflammatory properties of A. altilis protein hydrolysates. Protein was isolated from A. altilis and hydrolysed with pepsin and trypsin separately using different enzyme: substrate ratios (1:8, 1:16, 1:32). Antioxidant properties investigated included Fe²⁺-chelating, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide radical scavenging activities. Anti-inflammatory activities were determined using effects on hypotonic solution-induced cell lysis on red blood cell membrane stabilisation and heat-induced protein denaturation. The degree of hydrolysis of trypsin hydrolysate increased with increasing enzyme-substrate ratio, while pepsin hydrolysate decreased as the enzyme-substrate ratio increased. The dominant amino acids in A. altilis protein and hydrolysates were glutamate, aspartate and leucine. Protein hydrolysates obtained from pepsin and trypsin digestion had DPPH scavenging abilities of 43.0 ± 0.01% and 22.2 ± 0.01%, respectively. However, trypsin-hydrolysed protein had a high Fe²⁺-chelating ability, while pepsin-hydrolysed protein had high hydrogen peroxide scavenging ability. Trypsin-hydrolysed protein showed good membrane stability and inhibition of protein denaturation. The results indicated that A. altilis protein hydrolysates possess significant antioxidant and anti-inflammatory effects and can further lend support to food industries as functional foods.

Peptides and protein hydrolysates exhibiting anti-inflammatory activity: sources, structural features and modulation mechanisms

Inflammation is the response of the immune system to harmful stimuli such as tissue injury, infection or toxic chemicals, which has the aim of eliminating irritants or pathogenic microorganisms and enhancing tissue repair. Uncontrolled long-lasting acute inflammation can gradually progress to chronic, causing a variety of chronic inflammatory diseases that are usually treated with anti-inflammatory drugs, but most of them are inadequate to control chronic responses and are also associated with adverse side effects. Thus, many efforts are being directed to develop alternative and more selective anti-inflammatory therapies from natural products. One main field of interest is the obtaining of bioactive peptides exhibiting anti-inflammatory activity from sustainable protein sources like edible insects or agroindustry and fishing by-products. This work highlighted the structure-activity relationship of anti-inflammatory peptides. Small peptides with molecular weight under 1 kDa and amino acid chain length between 2 to 20 residues are generally the most active because of the higher probability to be absorbed in the intestine and penetrate into cells when compared with the larger size peptides. The presence of hydrophobic (Val, Ile, Pro) and positively charged (His, Arg, Lys) amino acids is another common occurrence for anti-inflammatory peptides. Interestingly, a high percentage (77%) of these bioactive peptides can be found in alternative sustainable protein sources such as Tenebrio molitor or sunflower, apart from its original protein source. However, not all of these peptides with anti-inflammatory potential in vitro achieve good scores by the in silico bioactivity predictors studied. Therefore, it is essential to implement current bioinformatics tools, in order to complement in vitro experiments with prior prediction of potential bioactive peptides.

Curcumin-Added Whey Protein Positively Modulates Skeletal Muscle Inflammation and Oxidative Damage after Exhaustive Exercise

(1) Background: Exhaustive exercise can induce muscle damage. The consumption of nutritional compounds with the ability to positively influence the oxidative balance and an exacerbated inflammatory process has been previously studied. However, little is known about the nutritional value of curcumin (CCM) when mixed with whey protein concentrate (WPC). This study was developed to evaluate the effect of CCM-added WPC on inflammatory and oxidative process control and histopathological consequences in muscle tissue submitted to an exhaustive swimming test (ET). (2) Methods: 48 animals were randomly allocated to six groups (n = 8). An ET was performed 4 weeks after the start of the diet and animals were euthanized 24 h post ET. (3) Results: WPC + CCM and CCM groups reduced IL-6 and increased IL-10 expression in muscle tissue. CCM reduced carbonyl protein after ET compared to standard AIN-93M ET and WPC + CCM ET diets. Higher nitric oxide concentrations were observed in animals that consumed WPC + CCM and CCM. Consumption of WPC + CCM or isolated CCM reduced areas of inflammatory infiltrate and fibrotic tissue in the muscle. (4) Conclusions: WPC + CCM and isolated CCM contribute to the reduction in inflammation and oxidative damage caused by the exhaustive swimming test.

Whey protein hydrolysate mitigates both inflammation and endotoxin tolerance in THP-1 human monocytic leukemia cells

INTRODUCTION

It is important to control both inflammation and immunosuppression after severe insults, such as sepsis, trauma, and surgery. Endotoxin tolerance is one of the immunosuppressive conditions and it has been known that endotoxin tolerance relates to poorer clinical outcomes in patients with severe insults. This study investigated whether whey protein hydrolysate (WPH) mitigates inflammation and endotoxin tolerance in THP-1 human monocytic leukemia cells.

METHODS

Endotoxin tolerance can be experimentally reproduced by two consecutive stimulations with lipopolysaccharide (LPS). THP-1 cells were incubated with LPS and WPH (first stimulation). After collecting the culture supernatant to evaluate the effect on inflammation, the cells were washed and restimulated by 100 ng/ml LPS (second stimulation). The culture supernatant was again collected to evaluate the effect on endotoxin tolerance. Concentrations of LPS and WPH in the first stimulation were adjusted to evaluate their dose dependency. Cytokine levels in the supernatant were determined by enzyme-linked immunosorbent assay. Statistical analysis was performed using the student's t-test or Dunnett's test.

RESULTS

Five mg/ml WPH significantly decreased interleukin (IL)-6 (p = .006) and IL-10 (p < .001) levels after the first LPS stimulation (1000 ng/ml). WPH significantly increased tumor necrosis factor-alpha (p < .001) and IL-10 (p = .014) levels after the second LPS stimulation. The suppressive effect of WPH on inflammation and endotoxin tolerance was dependent on the concentrations of LPS and WPH. The effective dose of WPH for endotoxin tolerance was lower than its effective dose for inflammation.

CONCLUSION

WPH mitigated both inflammation and endotoxin tolerance. Therefore, WPH might be a candidate for valuable food ingredients to control both inflammation and immunosuppression after severe insults.

Comparative assessment of antioxidant and immunomodulatory properties of skimmed milk protein hydrolysates and their incorporation in beverage mix

BACKGROUND

Milk-derived protein hydrolysates have generated a great deal of interest recently due to their numerous beneficial health effects. However, there are few comparative studies on protein hydrolysates from different dairy species, their production, characterization, and bioactivity. In the present study, skimmed milk from both major and minor dairy species was hydrolyzed with alcalase, and its protein profiles were studied using tricine polyacrylamide gel electrophoresis and reverse phase-high protein liquid chromatography. The antioxidant and in vitro immunostimulatory properties were determined.

RESULTS

Iron chelation activity was highest in hydrolysates of whey (25.00 ± 0.32 mmol L^-1 ), casein (25.14 ± 0.34 mmol L^-1 ), colostrum (24.52 ± 0.28 mmol L^-1 ), and skimmed cattle milk (24.21 ± 0.26 mmol L^-1 ). α,α-Diphenyl-β-picrylhydrazyl scavenging and 2,2'-azobis(2-amidino-propane) dihydrochloride activity was lowest in skimmed donkey milk protein hydrolysates (MPHs) (IC₅₀ : 5.37 ± 0.05 mg mL^-1 and 151.59 ± 2.1 mg mL^-1 ). Production of nitric oxide and phagocytosis activity in RAW 264.7 (murine macrophage cell line) was significantly higher among whey and buffalo skimmed milk protein hydrolysate-treated groups as compared with the untreated group. The incorporation of whey protein hydrolysate and skimmed buffalo milk protein hydrolysate were sensorially acceptable at 10% level in beverage mix.

CONCLUSION

This study comparatively evaluates the antioxidative and immunomodulatory properties of different skimmed MPHs and their potential applications as ingredients in pediatric, geriatric, and other health-promoting foods. © 2022 Society of Chemical Industry.

Peptides, Exopolysaccharides, and Short-Chain Fatty Acids from Fermented Milk and Perspectives on Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are characterized by chronic inflammatory processes and an imbalanced immune response along the gastrointestinal (GI) tract. Pharmacological treatments have been widely used, although their long-term application has adverse side effects. On the other hand, milks fermented with specific lactic acid bacteria (LAB) have been shown to be useful as alternative or complementary aids. Many metabolites such as peptides, exopolysaccharides, and short-chain fatty acids are produced during milk fermentation. These components have been shown to change the pH of the gastrointestinal lumen, aid intestine mucosal recovery, modulate the microbiota, and reduce the inflammatory response (innate and adaptive immune system), both in vitro and in vivo. Therefore, the objective of the present review is to describe how these bioactive compounds from fermented milk by specific LAB can decrease the deleterious symptoms of inflammatory bowel disease.

Antioxidant and immunomodulatory potency of Lacticaseibacillus rhamnosus NCDC24 fermented milk-derived peptides: A computationally guided in-vitro and ex-vivo investigation

Infections of microbial and non-microbial origins have been associated with significant immunological manifestations, thereby underscoring the need for a thorough understanding and investigation of novel immunomodulatory and antioxidant molecules that could prevent these incidences. To this end, we herein aim to identify fermented milk peptides with antioxidant and immunomodulatory properties that could be exploited for specific future applications. Our computational prediction models indicate that these peptides are non-toxic and possess considerable hydrophobicity (19.82-38.96 %) and functionality. Further analyses reveal that two of the four peptides, i.e., Pep 1 (AGWNIPM) and Pep 4 (YLGYLEQLLR), possess higher in-vitro antioxidant activity. The immunomodulatory potential of these two peptides (Pep 1 and Pep 4) is further demonstrated by using a combination of molecular simulation trajectory and ex-vivo approaches. Both peptides demonstrate ability to control the production of pro- inflammatory (TNF-α, IL-1, and IL-6) and anti-inflammatory (IL-10) cytokines as well as nitric oxide release in LPS-stimulated murine peritoneal macrophages. Similarly, peptide interferences also lead to significant (P < 0.05) improvement in macrophage phagocytic capacity. Taken together, these findings highlight the antioxidant and immunomodulatory properties of fermented milk peptides (Pep 1 and Pep 4) within the cellular environment and should facilitate prospective studies exploring such bioactive peptides and related functional molecules mediating the benefits of fermented milk products on human health.

Significance of whey protein hydrolysate on anti-oxidative, ACE-inhibitory and anti-inflammatory activities and release of peptides with biofunctionality: an in vitro and in silico approach

The study aimed to investigate potent antioxidant activities (ABTS assay, Hydroxyl free radical scavenging assay, and Superoxide free radical assay), ACE inhibitory activity, and anti-inflammatory activity in the WPC (whey protein concentrate) hydrolysate using Alcalase. The hydrolysis conditions (addition rate and incubation times) for peptide synthesis were also optimized using proteolytic activity. The generation of proinflammatory cytokines by lipopolysaccharide-treated murine macrophages was reduced when the protein hydrolysate concentration was low. In comparison to unhydrolyzed WPC, SDS-PAGE examination revealed no protein bands in WPC hydrolysates. Two-Dimensional (2D) gel electrophoresis did not show any protein spots. Using the 'In-solution trypsin digestion' approach, the trypsin digested protein samples were put into RPLC/MS for amino acid sequencing. Peptides were also identified using RPLC/MS on fractions of 3 and 10 kDa permeates and retentates. The MASCOT database was used to look up the raw masses of LC/MS. By comparing hydrolyzed whey protein to the BLASTp (NCBI), PIR, BIOPEP, and AHTPDB databases, novel antioxidative and ACE inhibitory peptides were reported.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05282-3.

Bioactive peptides of whey: obtaining, activity, mechanism of action, and further applications

Bioactive peptides derived from diverse food proteins have been part of diverse investigations. Whey is a rich source of proteins and components related to biological activity. It is known that proteins have effects that promote health benefits. Peptides derived from whey proteins are currently widely studied. These bioactive peptides are amino acid sequences that are encrypted within the first structure of proteins, which required hydrolysis for their release. The hydrolysis could be through in vitro or in vivo enzymatic digestion and using microorganisms in fermented systems. The biological activities associated with bio-peptides include immunomodulatory properties, antibacterial, antihypertensive, antioxidant and opioid, etc. These functions are related to general conditions of health or reduced risk of certain chronic illnesses. To determine the suitability of these peptides/ingredients for applications in food technology, clinical studies are required to evaluate their bioavailability, health claims, and safety of them. This review aimed to describe the biological importance of whey proteins according to the incidence in human health, their role as bioactive peptides source, describing methods, and obtaining technics. In addition, the paper exposes biochemical mechanisms during the activity exerted by biopeptides of whey, and their application trends.

Metformin Improves the Prognosis of Adult Mice with Sepsis-Associated Encephalopathy Better than That of Aged Mice

Sepsis-associated encephalopathy (SAE) is often associated with increased ICU occupancy and hospital mortality and poor long-term outcomes, with currently no specific treatment. Pathophysiological mechanisms of SAE are complex and may involve activation of microglia, multiple intracranial inflammatory factors, and inflammatory pathways. We hypothesized that metformin may have an effect on microglia, which affects the prognosis of SAE. In this study, metformin treatment of mice with SAE induced by lipopolysaccharide (LPS) reduced the expression of microglia protein and related inflammatory factors. Poor prognosis of SAE is related to increased expression of tumor necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) in brain tissues. Levels of inflammatory cytokines produced by LPS-induced SAE mouse microglia were significantly increased compared with those in the sham group. In addition, ionized calcium-binding adapter molecule 1 (Iba-1) was significantly reduced in metformin-treated SAE mice compared with untreated SAE mice, suggesting that metformin can reduce microgliosis and inhibit central nervous system inflammation, thereby improving patient outcomes. In conclusion, our results stipulate that metformin inhibits inflammation through the adenosine 5′-monophosphate (AMP-) activated protein kinase pathway by inhibiting nuclear factor kappa beta (NF-κB). Metformin can partially reverse the severe prognosis caused by sepsis by blocking microglial proliferation and inhibiting the production of inflammatory factors.

In Vitro Anti-Inflammatory Activity of Peptides Obtained by Tryptic Shaving of Surface Proteins of Streptococcus thermophilus LMD-9

Streptococcus thermophilus, a lactic acid bacterium widely used in the dairy industry, is consumed regularly by a significant proportion of the population. Some strains show in vitro anti-inflammatory activity which is not fully understood. We hypothesized that peptides released from the surface proteins of this bacterium during digestion could be implied in this activity. Consequently, we prepared a peptide hydrolysate by shaving and hydrolysis of surface proteins using trypsin, and the origin of peptides was checked by liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis. Most of the identified peptides originated from bacterial cell surface proteins. The anti-inflammatory activity of peptide hydrolysate was investigated under inflammatory conditions in two cell models. Peptide hydrolysate significantly decreased secretion of pro-inflammatory cytokine IL-8 in lipopolysaccharide (LPS)-stimulated human colon epithelial HT-29 cells. It also reduced the production of pro-inflammatory cytokines IL-8, IL-1β and the protein expression levels of Pro-IL-1β and COX-2 in LPS-stimulated THP-1 macrophages. The results showed that peptides released from bacterial surface proteins by a pancreatic protease could therefore participate in an anti-inflammatory activity of S. thermophilus LMD-9 and could prevent low-grade inflammation.

The Anti-Inflammatory Effect of Bovine Bone-Gelatin-Derived Peptides in LPS-Induced RAW264.7 Macrophages Cells and Dextran Sulfate Sodium-Induced C57BL/6 Mice

The bioactive peptides hydrolyzed from bone collagen have been found to possess health-promoting effects by regulating chronic diseases such as arthritis and hypertension. In the current study, the anti-inflammatory effect of bovine bone gelatin peptides (GP) was evaluated in 264.7 macrophages cells and followed by animal trials to investigate their interference on inflammatory cytokines and gut microbiota compositions in dextran sodium sulfate (DSS)-induced C57BL/6 mice. The GP was demonstrated to alleviate the extra secretion of interleukin-6 (IL-6), nitric oxide (NO) and tumor necrosis factor-α(TNF-α) in lipopolysaccharide (LPS)-induced RAW264.7 cells. In DSS-induced colitis mice, the gavage of GP was demonstrated to ameliorate the IBD symptoms of weight loss, hematochezia and inflammatory infiltration in intestinal tissues. In serum, the proinflammatory cytokines (TNF-α,IL-6, MCP-1, IL-1β) were suppressed along with the decreasing effect on toll-like receptor 4 and cyclooxygenase-2 by GP treatment. In the analysis of gut microbiota, the GP was checked to modulate the abundance of Akkermansia, Parasutterella, Peptococcus, Bifidobacterium and Saccharibacteria. The above results imply that GP could attenuate DSS-induced colitis by suppressing the inflammatory cytokines and regulating the gut microbiota.

Whey fermented by Enterococcus faecalis M157 exhibits antiinflammatory and antibiofilm activities against oral pathogenic bacteria

The aim of the present study was to investigate the antiinflammatory and antibiofilm effects of whey fermented by Enterococcus faecalis M157 (M157-W) against oral pathogenic bacteria. The M157-W significantly inhibited IL-1β, IL-6, and nitric oxide induced by the lipopolysaccharide of Porphyromonas gingivalis in RAW 264.7 cells. The M157-W also inhibited the production of IL-1β and IL-8 in human periodontal ligament cells. Treatment with M157-W suppressed the phosphorylation of mitogen-activated protein kinases as well as the activation of nuclear factor-κB in RAW 264.7 cells stimulated by P. gingivalis lipopolysaccharide. Furthermore, M157-W dose-dependently inhibited Streptococcus mutans biofilm, whereas unfermented whey did not inhibit the biofilm. Treatment with M157-W significantly suppressed gtfB, gtfC, and gtfD gene expression in S. mutans compared with the control (0 μg/mL), indicating that M157-W inhibits S. mutans biofilm formation by reducing the synthesis of extracellular polymeric substances. Collectively, these results suggest that M157-W has antiinflammatory and antibiofilm activities against oral pathogenic bacteria.

Copper-Binding Peptides Attenuate Microglia Inflammation through Suppression of NF-kB Pathway

SCOPE

Activation of microglia, the resident immune cells of the central nervous system, has been related to the etiology and progression of neurodegenerative diseases; thus, finding novel approaches to suppress the neuroinflammatory process is of utmost relevance.

METHODS AND RESULTS

The anti-inflammatory activity of whey Cu-, Fe-, and Zn-binding peptides and their possible underlying mechanism of action were evaluated in microglia. Whey metal-binding peptides decreased nitric oxide production and tumor necrosis factor α (TNF-α) at mRNA and protein levels by stimulated BV-2 microglia in comparison to the control with no peptide treatment. The hydrophobicity, specific sequences, and possible synergistic effects seem to play a role. Cu-binding peptides (Cu-bp) presented anti-inflammatory activity both in BV-2 and primary microglia cultures. These peptides exert their action by suppressing nuclear factor kappa B (NF-kB) pathway since nuclear translocation of NF-kB p65 is decreased by roughly 30% upon Cu-bp treatment. Specific sequences identified in Cu-bp showed high affinity to bind NF-kB p65 by molecular docking (up to -8.8 kcal mol-1 ), corroborating the immunofluorescence studies.

CONCLUSION

Cu-bp represent food-derived peptides that may be useful for neuroprotective purposes. Chelation of copper excess in the CNS and the bioavailability of such peptides, as well as their behavior in in vivo models, deserve further research for future applications.

Anti-inflammatory and Antioxidant Activity of Peptides From Ethanol-Soluble Hydrolysates of Sturgeon (Acipenser schrenckii) Cartilage

Research has shown that cartilage containing chondroitin sulfate and protein presents versatile bioactivities. Chondroitin sulfate in cartilage is beneficial to activate the immune system while the protein/peptide has not been fully understood. The current study investigated the antioxidant and anti-inflammatory properties of ethanol-soluble hydrolysates of sturgeon cartilage (ESCH) prepared through hot-pressure, enzymatic hydrolysis and ethanol extraction. UV spectrum, IR and agarose gel electrophoresis results suggested the successful exclusion of chondroitin sulfate from peptides. Nitric oxide (NO) floods in cells activated by inflammation. It was inhibited when administrated with ESCH. To further explain the observed anti-inflammatory activity, ESCH was separated with Sephadex G-15 into 3 components, among which F3 showed a higher NO inhibition rate and significantly reduced the production of the proinflammatory cytokine IL-6. In addition, the yield of IL-10 increased. Western blotting suggested that F3 downregulated the NO content and IL-6 level by suppressing Mitogen-activated protein kinases (MAPK) channels. Moreover, both ESCH and F3 showed DPPH and ABTS free radical scavenging abilities which was possibly related to the anti-inflammatory property. These results indicated that ESCH behaved anti-inflammatory and antioxidant activities. Cartilage may be a good source to produce anti-inflammatory peptides.

Protective effects of potential probiotic Lactobacillus rhamnosus (MTCC-5897) fermented whey on reinforcement of intestinal epithelial barrier function in a colitis-induced murine model

Fermented foods provide essential nutritional components and bioactive molecules that have beneficial effects on several gastrointestinal disorders. In the present investigation, the potential protective effects of whey fermented with probiotic Lactobacillus rhamnosus MTCC-5897 on gastrointestinal health in a murine ulcerative colitis model induced by dextran sulfate sodium (DSS) were evaluated. Pre-consumption of whey fermented with probiotic L. rhamnosus (PFW) before colitis induction significantly reduced (p < 0.01) the disease activity index and improved (p < 0.05) the hematological parameters and histological scores. The considerably diminished levels (p < 0.01) of pro-inflammatory markers (IL-4, TNF-α, CRP and MPO activity) and the enhanced (p < 0.05) levels of the anti-inflammatory cytokine TGF-β with IgA in the intestine upon feeding PFW appeared to prevent inflammation on colitis induction. Transcriptional modulations in pathogen recognition receptors (TLR-2/4) and tight junctional genes (ZO-1, occludin, claudin-1) along with localized distribution of junctional (claudin-1, occludin and ZO-1) and cytoskeleton (actin) proteins improved immune homeostasis and intestinal barrier integrity. Besides, significantly reduced (p < 0.05) levels of the FITC-dextran marker in serum upon consumption of PFW directly confirmed the healthy status of the host gut.

Oral delivery of self-assembling bioactive peptides to target gastrointestinal tract disease

Peptides are known for their diverse bioactivities including antioxidant, antimicrobial, and anticancer activity, all three of which are potentially useful in treating colon-associated diseases. Beside their capability to stimulate positive health effects once released in the body, peptides are able to form useful nanostructures such as hydrogels. Combining peptide bioactivity and peptide gel-forming potentials can create interesting systems that can be used for oral delivery. This combination, acting as a two-in-one system, has the potential to avoid the need for delicate entrapment of a drug or natural bioactive compound. We here review the context and research progress, to date, in this area.

Protective effects of whey protein concentrate admixtured of curcumin on metabolic control, inflammation and oxidative stress in Wistar rats submitted to exhaustive exercise

This work aimed to evaluate the effects of whey protein concentrate (WPC) admixtured of curcumin on metabolic control, inflammation and oxidative stress in Wistar rats submitted to exhaustive exercise. A total of forty-eight male rats were divided into six experimental groups (n 8): standard diet group (AIN-93M), standard diet submitted to exhaustion test group (AIN-93M ET), WPC admixtured of curcumin group (WPC + CCM), WPC + CCM submitted to exhaustion test group (WPC + CCM ET), CCM group and CCM subjected to exhaustion test group (CCM ET). The swimming exhaustion test was performed after 4 weeks of experiment. The consumption of WPC + CCM as well as isolated CCM did not alter the biometric measurements, the animals' food consumption and the hepatic and kidney function, as well as the protein balance of the animals (P > 0·05), but reduced the glycaemia and the gene expression of TNF-α and IL-6 and increased the expression of IL-10 (P < 0·05). The animals that were submitted to the exhaustion test (AIN-93M ET) showed higher aspartate aminotransferase values when compared to the animals that did not perform the exercise (AIN-93 M) (P < 0·05). WPC + CCM reduced the concentration of nitric oxide, carbonylated protein and increased the concentration of catalase (P < 0·05). Both (WPC + CCM and CCM) were able to increase the concentrations of superoxide dismutase (P < 0·05). We concluded that the WPC admixtured of CCM represents a strategy capable of decreasing blood glucose and oxidative and inflammatory damage caused by exhaustive physical exercise in swimming.

Optimization of Jiuzao protein hydrolysis conditions and antioxidant activity in vivo of Jiuzao tetrapeptide Asp-Arg-Glu-Leu by elevating the Nrf2/Keap1-p38/PI3K-MafK signaling pathway

Tetrapeptide Asp-Arg-Glu-Leu (DREL) was isolated from Jiuzao protein hydrolysates (JPHs) by alkaline proteinase (AP) and exhibited antioxidant activity in the HepG2 cell model in the previous study. In this study, the hydrolysis method of Jiuzao protein (JP) was further optimized by using different proteinases under different conditions (i.e., temperature, time, ratio between proteinase and substrate, and pH). Considering the limitation of in vitro assays, the AAPH-induced oxidative stress Sprague-Dawley (SD) rat model was selected to measure the antioxidant capacity of DREL in vivo. Pepsin exhibited the highest hydrolysis degree under the optimum conditions after single factor analysis (SFA) among seven proteinases. The total yield of DREL in Jiuzao was 158.24 mg kg-1Jiuzao under the pepsin's optimum hydrolysis conditions determined by response surface methodology analysis (RSMA). In addition, DREL could activate the Nrf2/Keap1-p38/PI3K-MafK signaling pathway and downstream antioxidant enzymes to improve the antioxidant ability in vivo. DREL also preliminarily exhibited anti-inflammatory activity by inhibiting the secretion of inflammatory cytokines and the mediator through the activation of Nrf2. Of note, the addition of DREL in baijiu brought an inconspicuous change in the taste after sensory evaluation. This study finds out the better proteinase used for JP hydrolysis and verifies the antioxidant capacity of DREL in vivo, which provides a potential approach to apply functional components from Jiuzao for by-product utilization. Meanwhile the antioxidant function of baijiu or other foods can be increased through adding these functional peptides without affecting the original flavor and taste in the future.

Use of Alcalase in the production of bioactive peptides: A review

This review aims to cover the uses of the commercially available protease Alcalase in the production of biologically active peptides since 2010. Immobilization of Alcalase has also been reviewed, as immobilization of the enzyme may improve the final reaction design enabling the use of more drastic conditions and the reuse of the biocatalyst. That way, this review presents the production, via Alcalase hydrolysis of different proteins, of peptides with antioxidant, angiotensin I-converting enzyme inhibitory, metal binding, antidiabetic, anti-inflammatory and antimicrobial activities (among other bioactivities) and peptides that improve the functional, sensory and nutritional properties of foods. Alcalase has proved to be among the most efficient proteases for this goal, using different protein sources, being especially interesting the use of the protein residues from food industry as feedstock, as this also solves nature pollution problems. Very interestingly, the bioactivities of the protein hydrolysates further improved when Alcalase is used in a combined way with other proteases both in a sequential way or in a simultaneous hydrolysis (something that could be related to the concept of combi-enzymes), as the combination of proteases with different selectivities and specificities enable the production of a larger amount of peptides and of a smaller size.

The Potential of Food Protein-Derived Bioactive Peptides against Chronic Intestinal Inflammation

Inflammation can cause various chronic diseases like inflammatory bowel diseases. Various food protein-derived bioactive peptides (BAPs) with anti-inflammatory activity have the potential to manage these diseases. The aim of this paper is to overview the mechanisms and the molecular targets of BAPs to exert anti-inflammatory activity. In this review, the in vitro and in vivo effects of BAPs on intestinal inflammation are highlighted. The mechanism, pathways, and future perspectives of BAPs as the potential sources of therapeutic treatments to alleviate intestinal inflammation are provided, including nuclear factor-κB, mitogen-activated protein kinase, Janus kinase-signal transducer and activator of transcription, and peptide transporter 1 (PepT1), finding that PepT1 and gut microbiota are the promising targets for BAPs to alleviate the intestinal inflammation. This review provides a comprehensive understanding of the role of dietary BAPs in attenuating inflammation and gives a novel direction in nutraceuticals for people or animals with intestinal inflammation.

Molecular action mechanism of anti-inflammatory hydrolysates obtained from brewers' spent grain

BACKGROUND

Brewers' spent grain (BSG) is a relevant, protein-rich by-product of the brewing process. Protein hydrolysates from different sources exert immune-regulatory actions activating toll-like receptors (TLRs), nuclear factor kappa B (NFκB), and mitogen-activated protein kinases (MAPKs). Effects of gastrointestinal digestion have been poorly studied. Here, we studied the immune-regulatory effect of BSG hydrolysates, and their in-vitro-digested products, on rat splenocytes, macrophages, and T lymphocytes RESULTS: In primary cultures of rat spleen cells, BSG hydrolysates induced interleukin 10 and tumor necrosis factor production in basal conditions. Under stimulation with lipopolysaccharide or concanavalin A, hydrolysates further induced interleukin 10 production. Tumor necrosis factor and interferon-γ were inhibited in lipopolysaccharide- and concanavalin-A-stimulated cells respectively. In vitro gastrointestinal digestion attenuated the observed effects. Splenic macrophages and T lymphocytes behaved in a similar fashion. In spleen cells from TLR2^-/- and TLR4^-/- mice, immune-regulatory effects were greatly reduced or abrogated. The study of signal transduction pathways indicated a major involvement of NFκB, and the contribution of MAPKs p38, c-Jun N-terminal kinase, and extracellular signal-regulated kinases 1 and 2.

CONCLUSION

BSG hydrolysates, like those obtained from other food sources, regulate the immune response, involving TLR2 and TLR4 and the activation of NFκB and MAPKs, an effect partly maintained after in vitro gastrointestinal digestion. Our data support the hypothesis of a shared, rather unspecific, mechanism of action of protein hydrolysates. © 2020 Society of Chemical Industry.

Potential role of natural bioactive peptides for development of cosmeceutical skin products

In recent years, consumers' demand for cosmeceutical products with protective and therapeutic functions derived from natural sources have caused this industry to search for alternative active ingredients. Bioactive peptides have a wide spectrum of bioactivities, which make them ideal candidates for development of these cosmeceutical products. In vitro studies have demonstrated that bioactive peptides (obtained as extracts, hydrolysates, and/or individual peptides) exhibit biological properties including antioxidant, antimicrobial, and anti-inflammatory activities, in addition to their properties of inhibiting aging-related enzymes such as elastase, collagenase, tyrosinase and hyaluronidase. Some studies report multifunctional bioactive peptides that can simultaneously affect, beneficially, multiple physiological pathways in the skin. Moreover, in vivo studies have revealed that topical application or consumption of bioactive peptides possess remarkable skin protection. These properties suggest that bioactive peptides may contribute in the improvement of skin health by providing specific physiological functions, even though the mechanisms underlying the protective effect have not been completely elucidated. This review provides an overview of in vitro, in silico and in vivo properties of bioactive peptides with potential use as functional ingredients in the cosmeceutical field. It also describes the possible mechanisms involved as well as opportunities and challenges associated with their application.