Grape seed proanthocyanidin extract attenuates allergic inflammation in murine models of asthma

Protein aggregation model to explain the bioactivity of condensed tannins

Tannins are involved in the taste of foods and multi bioactivity of traditional herbal medicines. The characteristics of tannins are believed to derive from their connectivity with proteins. However, the mode of interaction between proteins and tannins is not yet understood because of the complexity of the tannin structure. Then this study aimed to elucidate the detail binding mode of tannin and protein by the ¹H-¹⁵N HSQC NMR method using the ¹⁵N-labeled MMP-1that have not been used so far. The HSQC results suggested cross-link sites between MMP-1s, which cause protein aggregation and inhibit MMP-1 activity. This study presents the first 3D protein aggregation model of condensed tannins, which is important for understanding the bioactivity of polyphenols. Furthermore, it can broaden the understanding of the range of interactions between other proteins and polyphenols.

In silico analysis of dietary polyphenols and their gut microbial metabolites suggest inhibition of SARS-CoV-2 infection, replication, and host inflammatory mediators

The outcome of SARS-CoV-2 infection ranges from asymptomatic to severe COVID-19 and death resulting from an exaggerated immune response termed cytokine storm. Epidemiological data have associated consumption of a high-quality plant-based diet with decreased incidence and severity of COVID-19. Dietary polyphenols and their microbial metabolites (MMs) have anti-viral and anti-inflammatory activities. Autodock Vina and Yasara were used in molecular docking and dynamics studies to investigate potential interactions of 7 parent polyphenols (PPs) and 11 MMs with the α- and Omicron variants of the SARS-CoV-2 spike glycoprotein (SGP), papain-like pro-tease (PLpro) and 3 chymotrypsin-like protease (3CLpro), as well as host inflammatory mediators including complement component 5a (C5a), C5a receptor (C5aR), and C-C chemokine receptor type 5 (CCR5). PPs and MMs interacted to varying degrees with residues on target viral and host inflammatory proteins showing potential as competitive inhibitors. Based on these in silico findings, PPs and MMs may inhibit SARS-CoV-2 infection, replication, and/or modulate host immunity in the gut or periphery. Such inhibition may explain why people that consume a high-quality plant-based diet have less incidence and severity of COVID-19.Communicated by Ramaswamy H. Sarma.

Box-Behnken Design: Optimization of Proanthocyanidin-Loaded Transferosomes as an Effective Therapeutic Approach for Osteoarthritis

Transferosomes are one of the vesicular carriers that have received extensive research and attention recently because of their capacity to get beyond the barriers posed by the stratum corneum to penetration. The intent of the current study is to optimize and evaluate proanthocyanidin (PAC) containing transferosomal transdermal gels. PAC-containing transferosomes were prepared using the film hydration method and then loaded into a 4% methylcellulose gel. A 2³ Box-Behnken design was used to optimize the PAC-loaded transferosomal gel, where the effects of phospholipid 90 G (X1), Tween 80 (X2), and sonication time (X3) were evaluated. The formulation factors, such as the drug entrapment efficiency percentage (PEE) and in vitro drug release, were characterized. A PEE of 78.29 ± 1.43% and a drug release in vitro at 6 h of 24.2 ± 1.25% were obtained. The optimized transferosomal-loaded proanthocyanidin (OTP) formulation penetrated the porcine skin at an excellent rate (0.123 ± 0.0067 mg/cm²/h). Stability tests were conducted for OTP to predict the effects of various temperature conditions on the physical appearance, drug content, and PEE for periods of 15, 30, and 45 days. Finally, this transferosomal system for transdermal PAC delivery may be a suitable alternative to the conventional treatment for osteoarthritis.

Dietary proanthocyanidins promote localized antioxidant responses in porcine pulmonary and gastrointestinal tissues during Ascaris suum-induced type 2 inflammation

Proanthocyanidins (PAC) are dietary polyphenols with putative anti-inflammatory and immunomodulatory effects. However, whether dietary PAC can regulate type-2 immune function and inflammation at mucosal surfaces remains unclear. Here, we investigated if diets supplemented with purified PAC modulated pulmonary and intestinal mucosal immune responses during infection with the helminth parasite Ascaris suum in pigs. A. suum infection induced a type-2 biased immune response in lung and intestinal tissues, characterized by pulmonary granulocytosis, increased Th2/Th1 T cell ratios in tracheal-bronchial lymph nodes, intestinal eosinophilia, and modulation of genes involved in mucosal barrier function and immunity. Whilst PAC had only minor effects on pulmonary immune responses, RNA-sequencing of intestinal tissues revealed that dietary PAC significantly enhanced transcriptional responses related to immune function and antioxidant responses in the gut of both naïve and A. suum-infected animals. A. suum infection and dietary PAC induced distinct changes in gut microbiota composition, primarily in the jejunum and colon, respectively. Notably, PAC consumption substantially increased the abundance of Limosilactobacillus reuteri. In vitro experiments with porcine macrophages and intestinal epithelial cells supported a role for both PAC polymers and PAC-derived microbial metabolites in regulating oxidative stress responses in host tissues. Thus, dietary PAC may have distinct beneficial effects on intestinal health during infection with mucosal pathogens, while having a limited activity to modulate naturally-induced type-2 pulmonary inflammation. Our results shed further light on the mechanisms underlying the health-promoting properties of PAC-rich foods, and may aid in the design of novel dietary supplements to regulate mucosal inflammatory responses in the gastrointestinal tract.

Therapeutic potential of plant-derived tannins in non-malignant respiratory diseases

Respiratory diseases are the major cause of human illness and death around the world. Despite advances in detection and treatment, very few classes of safe and effective therapy have been introduced to date. At present, phytochemicals are getting more attention because of their diverse beneficial activities and minimal toxicity. Tannins are polyphenolic secondary metabolites with high molecular weights, which are naturally present in a wide variety of fruits, vegetables, cereals, and leguminous seeds. Many tannins are endowed with well-recognized protective properties, such as anti-cancer, anti-microbial, anti-oxidant, anti-hyperglycemic, and many others. This review summarizes a large body of experimental evidence implicating that tannins are helpful in tackling a wide range of non-malignant respiratory diseases including acute lung injury (ALI), pulmonary fibrosis, asthma, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). Mechanistic pathways by which various classes of tannins execute their beneficial effects are discussed. In addition, clinical trials and our perspective on future research with tannins are also reviewed.

Proanthocyanidins: Components, Pharmacokinetics and Biomedical Properties

Proanthocyanidins (PAs) are a group of polyphenols enriched in plant and human food. In recent decades, epidemiological studies have upheld the direct relationship between PA consumption and health benefits; therefore, studies on PAs have become a research hotspot. Although the oral bioavailability of PAs is quite low, pharmacokinetics data revealed that some small molecules and colonic microbial metabolites of PAs could be absorbed and exert their health beneficial effects. The pharmacological effects of PAs mainly include anti-oxidant, anticancer, anti-inflammation, antimicrobial, cardiovascular protection, neuroprotection, and metabolism-regulation behaviors. Moreover, current toxicological studies show that PAs have no observable toxicity to humans. This review summarizes the resources, extraction, structures, pharmacokinetics, pharmacology, and toxicology of PAs and discusses the limitations of current studies. Areas for further research are also proposed.

Effect of Flavonoid Supplementation on Alveolar Bone Healing-A Randomized Pilot Trial

We investigated the effects of two common dietary supplements on bone healing in dental extraction sockets in humans. In this randomized pilot trial, male subjects took Grape Seed Extract [GSE] or Grapefruit Extract [GFE] starting two weeks prior to dental extraction and maintained this regimen for sixty days after surgery. Extraction sockets were filled with a collagen plug. After 24 h, a socket sample was collected and processed for quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and an 84-gene wound healing assay. Sixty days after tooth extraction, a core of newly formed bone was obtained prior to dental implant placement and processed for histology. qRT-PCR revealed that GFE led to a significant decrease in platelet-derived growth factor and interleukin (IL)1-β compared to GSE, and a significant decrease in IL-6 and CXCL2 compared to control. GSE led to a significant increase in coagulation factor Von Willebrand and inflammatory marker IL1-β compared to GFE. WISP1 and CXCL5 were upregulated in both groups. Overall, GFE showed a downregulation of inflammation and GSE led to a decrease in collagen density and increased osteoclasts. This pilot trial highlights the need for further investigation on the mechanism of action of such supplements on bone healing and oral health.

Grape seed proanthocyanidin extract alleviates arsenic-induced lung damage through NF-κB signaling

IMPACT STATEMENT

Arsenic-induced respiratory inflammatory damage is an important occupational hazard in many areas of the world, particularly in underdeveloped and developing countries. Effective treatments are lacking and expensive. Therefore, the aim of the study was to examine the anti-inflammatory effects of proanthocyanidin (PC) and the molecular mechanisms in vivo and in vitro. The present study showed that PC extracted from grape seed could attenuate the lung damage in a mouse model of arsenic poisoning. The effects were observed at the level of lung histology and inflammasome expression. This study suggests that a natural compound is effective in mitigating the toxic effects of arsenic in the lungs, providing an inexpensive and more readily accessible method for treating arsenic exposure in some parts of the world.

An Alternative Dendritic Cell-Induced Murine Model of Asthma Exhibiting a Robust Th2/Th17-Skewed Response

PURPOSE

Simple and reliable animal models of human diseases contribute to the understanding of disease pathogenesis as well as the development of therapeutic interventions. Although several murine models to mimic human asthma have been established, most of them require anesthesia, resulting in variability among test individuals, and do not mimic asthmatic responses accompanied by T-helper (Th) 17 and neutrophils. As dendritic cells (DCs) are known to play an important role in initiating and maintaining asthmatic inflammation, we developed an asthma model via adoptive transfer of allergen-loaded DCs.

METHODS

Ovalbumin (OVA)-loaded bone marrow-derived DCs (BMDCs) (OVA-BMDCs) were injected intravenously 3 times into non-anesthetized C57BL/6 mice after intraperitoneal OVA-sensitization.

RESULTS

OVA-BMDC-transferred mice developed severe asthmatic immune responses when compared with mice receiving conventional OVA challenge intranasally. Notably, remarkable increases in systemic immunoglobulin (Ig) E and IgG1 responses, Th2/Th17-associated cytokines (interleukin [IL]-5, IL-13 and IL-17), Th2/Th17-skewed T-cell responses, and cellular components, including eosinophils, neutrophils, and goblet cells, were observed in the lungs of OVA-BMDC-transferred mice. Moreover, the asthmatic immune responses and severity of inflammation were correlated with the number of OVA-BMDCs transferred, indicating that the disease severity and asthma type may be adjusted according to the experimental purpose by this method. Furthermore, this model exhibited less variation among the test individuals than the conventional model. In addition, this DCs-based asthma model was partially resistant to steroid treatment.

CONCLUSIONS

A reliable murine model of asthma by intravenous (i.v.) transfer of OVA-BMDCs was successfully established without anesthesia. This model more accurately reflects heterogeneous human asthma, exhibiting a robust Th2/Th17-skewed response and eosinophilic/neutrophilic infiltration with good reproducibility and low variation among individuals. This model will be useful for understanding the pathogenesis of asthma and would serve as an alternative tool for immunological studies on the function of DCs, T-cell responses and new drugs.

Proanthocyanidin Encapsulated in Ferritin Enhances Its Cellular Absorption and Antioxidant Activity

Proanthocyanidins (PAs) possess superior antioxidant properties and nutritious value, however, low bioavailability and stability limit their applications. Here, we developed a novel method to encapsulate PA dimers successfully into horse spleen apoferritin (apoHSF) using a disassembly/reassembly method based on pH change. The PA-HSF nanoparticles were characterized using fluorescence spectroscopy, transmission electron microscopy, circular dichroism, and high-performance liquid chromatography. One apoferritin cage could approximately encapsulate 25.6 molecules of the PA dimer. The results showed that the encapsulation of the PA dimers protected it from the damage of oxidants and temperature below room temperature would be an appropriate condition for HSF-578 solution storage. Moreover, HepG2 cell monolayer absorption and adhesion analyses indicated that the PA dimers encapsulated within apoHSF cages were more efficient in transport. In addition, it was indicated that the PA-HSF nanoparticles had higher cellular antioxidant activity. The novel strategy provided in this study indicates that the protein cage structures like ferritin have potential to be applied in the field of food nutrition.

Proanthocyanidins: A comprehensive review

Proanthocyanidins are condensed tannins with various pharmacological properties. These phytochemicals are considered as 'offense and defense molecules because of their human health benefits. The validation of their diverse health aspects, namely, antioxidant, anticancer, antidiabetic, neuroprotective, and antimicrobial has earned them repute in thermochemistry. Proanthocyanidins are oligo- or polymers of monomeric flavan-3-ols produced as an end product of flavonoid biosynthetic pathway. Agricultural wastes and food processing wastes contain immense amount of proanthocyanidins, exploitation of which can be a sustainable source of dietary supplements and functional ingredients. The current review article discusses recent developments in the health promoting properties of proanthocyanidins and the associated hurdles.

Grape Seed Proanthocyanidin Extract Alleviates AflatoxinB₁-Induced Immunotoxicity and Oxidative Stress via Modulation of NF-κB and Nrf2 Signaling Pathways in Broilers

Aflatoxin B₁ (AFB₁) is a widely spread mycotoxin contaminates food and feed, causing severe oxidative stress damages and immunotoxicity. Grape seed proanthocyanidin (GSPE), a natural antioxidant with wide range of pharmacological and medicinal properties. The goal of the present study was to investigate the protective effects of GSPE against AFB₁-induced immunotoxicity and oxidative stress via NF-κB and Nrf2 signaling pathways in broiler chickens. For the experiment, 240 one-day old Cobb chicks were allocated into four dietary treatment groups of six replicates (10 birds per replicate): 1. Basal diet (control); 2. Basal diet + AFB₁ 1mg/kg contaminated corn (AFB₁); 3. Basal diet + GSPE 250 mg/kg (GSPE); 4. Basal diet + AFB₁ 1 mg/kg + GSPE 250 mg/kg (AFB₁ + GSPE). The results showed that GSPE significantly decreased serum inflammatory cytokines TNF-α, IFN-γ, IL-1β, IL-10, and IL-6 induced by AFB₁. Similarly, GSPE + AFB₁ treated group revealed a significant decrease in mRNA expressions of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β, and IL-6) in the splenic tissue compared to the AFB₁ treatment group. In addition, western blotting results manifested that GSPE treatment normalized the phosphorylation of nuclear factor kappa B (p65) and the degradation of IκBα protein induced by AFB₁. Furthermore, GSPE enhanced the antioxidant defense system through activating the nuclear factor-erythroid-2-related factor (Nrf2) signaling pathway. The mRNA and protein expression level of Nrf2 and its down streaming associated genes were noted up-regulated by the addition of GSPE, and down-regulated in the AFB₁ group. Taken together, GSPE alleviates AFB₁-induced immunotoxicity and oxidative damage by inhibiting the NF-κB and activating the Nrf2 signaling pathways in broiler chickens. Conclusively, our results suggest that GSPE could be considered as a potential natural agent for the prevention of AFB₁-induced immunotoxicity and oxidative damage.

Progress in the understanding of the pathology of allergic asthma and the potential of fruit proanthocyanidins as modulators of airway inflammation

Allergic asthma is a chronic inflammatory lung disease characterized by sensitization of the airways, and the development of immunoglobulin E antibodies, to benign antigens. The established pathophysiology of asthma includes recurrent lung epithelial inflammation, excessive mucus production, bronchial smooth muscle hyperreactivity, and chronic lung tissue remodeling, resulting in reversible airflow restriction. Immune cells, including eosinophils and the recently characterized type 2 innate lymphoid cells, infiltrate into the lung tissue as part of the inflammatory response in allergic asthma. It is well established that a diet high in fruits and vegetables results in a reduction of the risk of developing inflammatory diseases. Secondary plant metabolites, such as proanthocyanidins which are found in apples, blackcurrants, boysenberries, cranberries, and grapes, have shown promising results in reducing or preventing allergic asthma airway inflammation. Recent evidence has also highlighted the importance of microbiome-mediated metabolism of plant polyphenols in modulating the immune system. In this review, we will discuss advances in our understanding of the pathophysiology of allergic asthma, including the role of the microbiome in lung immune function, and how proanthocyanidins modulate the airway inflammation. We will highlight the potential of dietary proanthocyanidins to impact on allergic asthma and the immune system.

Dietary Intake of Flavonoids and Ventilatory Function in European Adults: A GA²LEN Study

BACKGROUND

Flavonoids exert anti-inflammatory properties and modulate oxidative stress in vitro, suggesting a protective effect on lung function, but epidemiological studies examining this association are scarce.

METHODS

A stratified random sample was drawn from the GA²LEN screening survey, in which 55,000 adults aged 15 to 75 answered a questionnaire on respiratory symptoms. Post-bronchodilator spirometry was obtained from 2850 subjects. Forced vital capacity (FVC), the ratio between the forced exhaled volume in 1 second (FEV₁) and FVC (FEV₁/FVC), FVC below lower limit of normal (FVC < LLN), and FEV₁/FVC < LLN were calculated. Intake of the six main subclasses of flavonoids was estimated using the GA²LEN Food Frequency Questionnaire. Adjusted associations between outcomes and each subclass of flavonoids were examined with multivariate regressions. Simes' procedure was used to test for multiple comparisons.

RESULTS

A total of 2599 subjects had valid lung function and dietary data. A lower prevalence of FVC < LLN (airway restriction) was observed in those with higher total flavonoid (adjusted odds ratio (aOR), higher vs. lowest quintile intake 0.58; 95% Confidence Interval (CI) 0.36, 0.94), and pro-anthocyanidin intakes (aOR 0.47; 95% CI 0.27, 0.81). A higher FEV₁/FVC was associated with higher intakes of total flavonoids and pro-anthocyanidins (adjusted correlation coefficient (a β-coeff 0.33; 0.10, 0.57 and a β-coeff 0.44; 95% CI 0.19, 0.69, respectively). After Simes' procedure, the statistical significance of each of these associations was attenuated but remained below 0.05, with the exception of total flavonoids and airway restriction.

CONCLUSIONS

This population-based study in European adults provides cross-sectional evidence of a positive association of total flavonoid intake and pro-anthocyanidins and ventilatory function, and a negative association with spirometric restriction in European adults.

Oligomeric proanthocyanidins attenuate airway inflammation in asthma by inhibiting dendritic cells maturation

To date, although a promising anti-inflammatory activity of oligomeric proanthocyanidins (OPCs) has been observed in asthma, the mechanism responsible for these immunomodulatory properties remains obscure. Dendritic cells (DCs) that reside in the airway have been widely perceived as an important contributor to asthma. Our study was to demonstrate OPCs' effects on maturation and immunoregulation of pulmonary CD11c⁺ dendritic cells (DCs). BALB/c mice were exposed to ovalbumin (OVA) to induce murine model of asthma. In addition, pulmonary DCs and bone marrow-derived DCs (BMDCs) cultures were used to evaluate impacts of OPCs on DCs function. The results obtained here indicated that OPCs treatment dramatically reduced airway inflammation, such as the infiltration of inflammatory cells and the levels of allergen-specific serum IgE and Th2 cytokines. The expression of co-stimulatory molecules especially CD86 distributed on pulmonary DCs and bone marrow-derived DCs (BMDCs) also markedly declined. The phosphorylation of cAMP responsive element-binding protein (CREB) was significantly inhibited while no changes were observed in the expression of cAMP responsive element modulator (CREM). By transferring BMDCs into the airways of naïve mice, we found that OPCs-treated DCs (DC+OVA+OPC) were much less potent in promoting CD4⁺ T cells proliferation than OVA-pulsed DCs (DC+OVA), followed by the ameliorated eosinophilic inflammation in airway. Our findings tailor a novel profile of OPCs in the regulation of DCs function, shedding new light on the therapeutic potential of OPCs in asthma management.

Protective effects of grape seed and skin extract against high-fat-diet-induced lipotoxicity in rat lung

BACKGROUND

Obesity is a public health problem characterized by increased fat accumulation in different tissues. Obesity is directly linked to breathing problems and medical complications with lung, including obstructive sleep apnea syndrome, obesity hypoventilation syndrome, chronic obstructive pulmonary disease, asthma….In the present work, we aimed to investigate the effect of high fat diet (HFD) on lung lipotoxicity, oxidative stress, fatty acid composition and proportions in lung and implication in asthma development. The likely protection provided by grape seed extract (GSSE) was also investigated.

METHODS

In order to assess HFD effect on lung and GSSE protection we used a rat model. We analyzed the lipid plasma profile, lung peroxidation and antioxidant activities (SOD, CAT and POD). We also analyzed transition metals (Ca2+, Mg2+, Zn2+ and iron) and lung free fatty acids using gas chromatography coupled to mass spectrometry (GC-MS).

RESULTS

HFD induced lipid profile imbalance increasing cholesterol and VLDL-C. HFD also induced an oxidative stress assessed by elevated MDA level and the drop of antioxidant activities such as SOD, CAT and POD. Moreover, HFD induced mineral disturbances by decreasing magnesium level and increasing Calcium and iron levels. HFD induced also disturbances in lung fatty acid composition by increasing oleic, stearic and arachidonic acids. Interestingly, GSSE alleviated all these deleterious effects of HFD treatment.

CONCLUSION

As a whole, GSSE had a significant preventive effect against HFD-induced obesity, and hence may be used as an anti-obesity agent, and a benefic agent with potential applications against damages in lung tissue.

Monitoring of compositional changes during berry ripening in grape seed extracts of cv. Sangiovese (Vitis vinifera L.)

BACKGROUND

Seed oil and flours have been attracting the interest of researchers and industry, since they contain various bioactive components. We monitored the effects of ripening on lipids, monomeric flavan-3-ols, proanthocyanidins and tocols concentration in seed extracts from organically cultivated cv. Sangiovese vines.

RESULTS

Linoleic acid was the most abundant fatty acid, followed by oleic, palmitic and stearic acids. The tocols detected were α-tocopherol, α-tocotrienol and γ-tocotrienol. The proanthocyanidins degree of polymerisation ranged from dimers to dodecamers; moreover, monomeric flavan-3-ols and polymeric proanthocyanidins were detected. Total flavan-3-ols (monomers, oligomers and polymers) concentration in grape seeds decreased during ripening.

CONCLUSIONS

Fatty acids reached the highest level in post-veraison. The concentration of these compounds varied considerably during ripening. Capric acid has been found for the first time in grape seeds. α-Tocopherol and γ-tocotrienol decreased during ripening, while α-tocotrienol increased. The HPLC analysis with fluorimetric detection, conducted for the first time on cv. Sangiovese, revealed that the concentration of flavan-3-ols monomers, oligomeric proanthocyanidins and polymers greatly changed during ripening. These results suggest that the timing of bunch harvest plays a crucial role in the valorisation of grape seed flour. © 2016 Society of Chemical Industry.

S-adenosylmethionine reduces airway inflammation and fibrosis in a murine model of chronic severe asthma via suppression of oxidative stress

Increased oxidative stress has an important role in asthmatic airway inflammation and remodeling. A potent methyl donor, S-adenosylmethionine (SAMe), is known to protect against tissue injury and fibrosis through modulation of oxidative stress. The aim of this study was to evaluate the effect of SAMe on airway inflammation and remodeling in a murine model of chronic asthma. A mouse model was generated by repeated intranasal challenge with ovalbumin and Aspergillus fungal protease twice a week for 8 weeks. SAMe was orally administered every 24 h for 8 weeks. We performed bronchoalveolar lavage (BAL) fluid analysis and histopathological examination. The levels of various cytokines and 4-hydroxy-2-nonenal (HNE) were measured in the lung tissue. Cultured macrophages and fibroblasts were employed to evaluate the underlying anti-inflammatory and antifibrotic mechanisms of SAMe. The magnitude of airway inflammation and fibrosis, as well as the total BAL cell counts, were significantly suppressed in the SAMe-treated groups. A reduction in T helper type 2 pro-inflammatory cytokines and HNE levels was observed in mouse lung tissue after SAMe administration. Macrophages cultured with SAMe also showed reduced cellular oxidative stress and pro-inflammatory cytokine production. Moreover, SAMe treatment attenuated transforming growth factor-β (TGF-β)-induced fibronectin expression in cultured fibroblasts. SAMe had a suppressive effect on airway inflammation and fibrosis in a mouse model of chronic asthma, at least partially through the attenuation of oxidative stress and TGF-β-induced fibronectin expression. The results of this study suggest a potential role for SAMe as a novel therapeutic agent in chronic asthma.

Intervention of Grape Seed Proanthocyanidin Extract on the Subchronic Immune Injury in Mice Induced by Aflatoxin B1

The aim was to investigate the prevention of grape seed proanthocyanidin extract (GSPE) on the subchronic immune injury induced by aflatoxin B1 (AFB1) and the possible ameliorating effect of GSPE in mice. The subchronic AFB1-induced immune injury mice model was set up with the continuous administration of 100 μg/kg body weight (BW) AFB1 for six weeks by intragastric administration. Then, intervention with different doses (50 and 100 mg/kg BW) of GSPE was conducted on mice to analyze the changes of body weight, immune organ index, antioxidant capability of spleen, serum immunoglobulin content, and the expression levels of inflammatory cytokines. The prevention of GSPE on the immune injury induced by AFB1 was studied. The GSPE could relieve the AFB1-induced reduction of body weight gain and the atrophy of the immune organ. The malondialdehyde (MDA) level of the spleen in the AFB1 model group significantly increased, but levels of catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-P_X), and superoxide dismutase (SOD) significantly decreased. The GSPE could significantly inhibit the oxidative stress injury of the spleen induced by AFB1. AFB1 exposure could not significantly change the contents of IgA, IgG, or IgM. AFB1 significantly improved the expression of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ). Additionally, GSPE could decrease the expression of these four proinflammatory factors to different degrees and inhibit the inflammatory reaction of mice. The results suggest that GSPE alleviates AFB1-induced oxidative stress and significantly improves the immune injury of mice induced by AFB1.

Senescence-Associated MCP-1 Secretion Is Dependent on a Decline in BMI1 in Human Mesenchymal Stromal Cells

AIMS

Cellular senescence and its secretory phenotype (senescence-associated secretory phenotype [SASP]) develop after long-term expansion of mesenchymal stromal cells (MSCs). Further investigation of this phenotype is required to improve the therapeutic efficacy of MSC-based cell therapies. In this study, we show that positive feedback between SASP and inherent senescence processes plays a crucial role in the senescence of umbilical cord blood-derived MSCs (UCB-MSCs).

RESULTS

We found that monocyte chemoattractant protein-1 (MCP-1) was secreted as a dominant component of the SASP during expansion of UCB-MSCs and reinforced senescence via its cognate receptor chemokine (c-c motif) receptor 2 (CCR2) by activating the ROS-p38-MAPK-p53/p21 signaling cascade in both an autocrine and paracrine manner. The activated p53 in turn increased MCP-1 secretion, completing a feed-forward loop that triggered the senescence program in UCB-MSCs. Accordingly, knockdown of CCR2 in UCB-MSCs significantly improved their therapeutic ability to alleviate airway inflammation in an experimental allergic asthma model. Moreover, BMI1, a polycomb protein, repressed the expression of MCP-1 by binding to its regulatory elements. The reduction in BMI1 levels during UCB-MSC senescence altered the epigenetic status of MCP-1, including the loss of H2AK119Ub, and resulted in derepression of MCP-1.

INNOVATION

Our results provide the first evidence supporting the existence of the SASP as a causative contributor to UCB-MSC senescence and reveal a so far unappreciated link between epigenetic regulation and SASP for maintaining a stable senescent phenotype.

CONCLUSION

Senescence of UCB-MSCs is orchestrated by MCP-1, which is secreted as a major component of the SASP and is epigenetically regulated by BMI1.

Proanthocyanidins improves lead-induced cognitive impairments by blocking endoplasmic reticulum stress and nuclear factor-κB-mediated inflammatory pathways in rats

Proanthocyanidins (PCs), a class of naturally occurring flavonoids, had been reported to possess a variety of biological activities, including anti-oxidant, anti-tumor and anti-inflammatory. In this study, we examined the protective effect of PCs against lead-induced inflammatory response in the rat brain and explored the potential mechanism of its action. The results showed that PCs administration significantly improved behavioral performance of lead-exposed rats. One of the potential mechanisms was that PCs decreased reactive oxygen species production and increased the total antioxidant capacity in the brains of lead-exposed rats. Furthermore, the results also showed that PCs significantly decreased the levels of tumor necrosis factor-α, interleukin 1β and cyclooxygenase-2 in the brains of lead-exposed rats. Moreover, PCs significantly decreased the levels of beta amyloid and phosphorylated tau in the brains of lead-treated rats, which in turn inhibited endoplasmic reticulum (ER) stress. PCs also decreased the phosphorylation of protein kinase RNA-like ER kinase, eukaryotic translation initiation factor-2, inositol-requiring protein-1, c-Jun N-terminal kinase, p38 and inhibited nuclear factor-κB nuclear translocation in the brains of lead-exposed rats. In conclusion, these results suggested that PCs could improve cognitive impairments by inhibiting brain oxidative stress and inflammatory response.