Modulating the p66shc signaling pathway with protocatechuic acid protects the intestine from ischemia-reperfusion injury and alleviates secondary liver damage

Protective effects of protocatechuic acid on growth performance, intestinal barrier and antioxidant capacity in broilers challenged with lipopolysaccharide

'Prohibition of the antibiotic uses' aggravates the problem of intestinal diseases in poultry, and nutritional regulation has become a research hotspot, such as supplementation with active ingredients derived from plants. This research was conducted to investigate the effects of protocatechuic acid (PCA) on growth, intestinal barrier, and antioxidant capacity of broilers injected with lipopolysaccharide (LPS). Four hundred and eighty 1-day-old yellow feather broilers were randomly allocated to four groups, each with six replicates of 20 broilers. The treatments were basal diet + saline injection (CON) or LPS injection (CON-LPS), and diets with 300 or 600 mg/kg PCA supplementation + LPS injection (P300, P600). Birds were injected intramuscularly on 17th and 19th day of age, then sampled on day 21. The LPS injection significantly decreased BW and average daily gain of broilers, and compared with birds in CON-LPS, PCA supplementation increased (P < 0.05) those variables; moreover, 300 mg/kg PCA also decreased the feed-to-gain ratio. No differences were observed in relative weights of immune organs (P > 0.05). LPS decreased the villus height/crypt depth ratio (V/C) in jejunum of broilers, while PCA (P300 and P600) increased (P < 0.05) the jejunal villus height and V/C compared with birds in CON-LPS. LPS challenge increased jejunal malondialdehyde (MDA) concentration and decreased total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities in plasma (P < 0.05); compared with birds in CON-LPS, jejunal and plasmal GSH-Px activity (P300 and P600) and jejunal T-SOD activity (P300) were decreased (P < 0.05), and hepatic MDA concentration (P600) was increased (P < 0.05). LPS significantly decreased the transcript abundances of OCLN, ZO-1, JAM2, MUC2, SOD1, CAT and GPX in jejunal mucosa of birds, and supplementation with PCA attenuated the decrease in OCLN, JAM2, and MUC2 expression compared with birds in CON-LPS; moreover, 600 mg/kg PCA offset the deduction in SOD1, CAT and GPX expression. In conclusion, dietary supplementation with PCA could improve antioxidant status and attenuate the damage in intestinal barrier and loss in growth performance of LPS-challenged broilers, and 600 mg/kg PCA showed more improved effects on antioxidant capacity.

Mechanism Involved in Acute Liver Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (I/R) is a common pathophysiological process, which can occur in many conditions such as acute enteric ischemia, severe burns, small intestinal transplantation, etc,. Ischemia-reperfusion of the intestine is often accompanied by distal organ injury, especially liver injury. This paper outlined the signal pathways and cytokines involved in acute liver injury induced by intestinal I/R: the NF-κB Signaling Pathway, the P66shc Signaling Pathway, the HMGB1 Signaling Pathway, the Nrf2-ARE Signaling Pathway, the AMPK-SIRT-1 Signaling Pathway and other cytokines, providing new ideas for the prevention and treatment of liver injury caused by reperfusion after intestinal I/R.

Antioxidant Effects of Protocatechuic Acid and Protocatechuic Aldehyde: Old Wine in a New Bottle

Phenolic compounds are naturally present as secondary metabolites in plant-based sources such as fruits, vegetables, and spices. They have received considerable attention for their antioxidant, anti-inflammatory, and anti-carcinogenic properties for protection against many chronic disorders such as neurodegenerative diseases, diabetes, cardiovascular diseases, and cancer. They are categorized into various groups based on their chemical structure and include phenolic acids, flavonoids, curcumins, tannins, and quinolones. Their structural variations contribute to their specific beneficial effects on human health. The antioxidant property of phenolic compounds protects against oxidative stress by up-regulation of endogenous antioxidants, scavenging free radicals, and anti-apoptotic activity. Protocatechuic acid (PCA; 3,4-dihydroxy benzoic acid) and protocatechuic aldehyde (PAL; 3,4-dihydroxybenzaldehyde) are naturally occurring polyphenols found in vegetables, fruits, and herbs. PCA and PAL are the primary metabolites of anthocyanins and proanthocyanidins, which have been shown to possess pharmacological actions including antioxidant activity in vitro and in vivo. This review aims to explore the therapeutic potential of PCA and PAL by comprehensively summarizing their pharmacological properties reported to date, with an emphasis on their mechanisms of action and biological properties.

Research progress on intervention effect and mechanism of protocatechuic acid on nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become a surge burden worldwide due to its high prevalence, with complicated deterioration symptoms such as liver fibrosis and cancer. No effective drugs are available for NALFD so far. The rapid growth of clinical demand has prompted the treatment of NAFLD to become a research hotspot. Protocatechuic acid (PCA) is a natural secondary metabolite commonly found in fruits, vegetables, grains, and herbal medicine. It is also the major internal metabolites of anthocyanins and other polyphenols. In the present manuscript, food sources, metabolic absorption, and efficacy of PCA were summarized while analyzing its role in improving NAFLD, as well as the mechanism involved. The results indicated that PCA could ameliorate NAFLD by regulating glucose and lipid metabolism, oxidative stress and inflammation, gut microbiota and metabolites. It was proposed for the first time that PCA might reduce NAFLD by enhancing the energy consumption of brown adipose tissue (BAT). However, the PCA administration mode and dose for NAFLD remain inconclusive. Fresh insights into the specific molecular mechanisms are required, while clinical trials are essential in the future. This review provides new targets and reasoning for the clinical application of PCA in the prevention and treatment of NAFLD.

Src homolog and collagen homolog1 isoforms in acute and chronic liver injuries

Src homolog and collagen homolog (SHC) proteins are adaptor proteins bound to cell surface receptors that play an important role in signal transduction and related diseases. As an important member of the SHC protein family, SHC1 regulates cell proliferation and apoptosis, reactive oxygen species (ROS) production, and oxidative stress. Three isomeric proteins namely, p46shc, p52shc, and p66shc, are produced from the same SHC1 gene locus. All the three proteins are found in the liver, and are widely expressed in various hepatic cells. SHC1 has been proven to be associated with acute and chronic liver injuries of different etiologies, and plays important roles in liver fibrosis and hepatocellular carcinoma (HCC). Therefore, this review summarizes recent studies that discuss and explore the role of SHC1 in the occurrence and progression of liver diseases. We also provide a theoretical basis for future studies.

Involvement of PTEN and FOXO3a Proteins in the Protective Activity of Protocatechuic Acid Against Cisplatin-Induced Ovarian Toxicity in Mice

The present study evaluated the effects of protocatechuic acid (PCA) after cisplatin-induced ovarian toxicity in mice and if PTEN and FOXO3a proteins are involved in PCA action. The mice were divided into five experimental groups (five animals per group) and treated once a day for 3 days as follows: (1) the control group was pretreated with oral administration (o.p.) of saline solution, followed by an intraperitoneal (i.p.) injection of saline solution. The other groups were pretreated (o.p.) with (2) saline solution (cisplatin group), (3) N-acetylcysteine (150 mg/kg of body weight), or with (4) 20 or (5) 50 mg/kg body weight of PCA, followed by 5 mg/kg body weight (i.p.) of cisplatin. Next, the ovaries were destined to histological (morphology and activation), immunohistochemical (PCNA and cleaved caspase-3 expression), and fluorescence (reactive oxygen species [ROS], glutathione [GSH], and active mitochondria levels) analyses. Moreover, the immunoreactivity for p-PTEN and p-FOXO3a was evaluated to investigate a potential mechanism by which PCA could prevent the cisplatin-induced ovarian damage. Pretreatment with N-acetylcysteine or 20 mg/kg PCA before cisplatin preserved the percentage of normal follicles and cell proliferation as observed in the control, reduced apoptosis and ROS levels, and showed higher active mitochondria and GSH levels than the cisplatin treatment (P < 0.05). Moreover, pretreatment with 20 mg/kg PCA decreased cisplatin-induced p-PTEN and increased (P < 0.05) nuclear export of p-FOXO3a. In conclusion, PCA at 20 mg/kg reduced apoptosis, maintained cell proliferation and mitochondrial function, reduced ROS production, and increased GSH expression likely through the involvement of PTEN and FOXO3a proteins.

The Effects and Mechanisms of Cyanidin-3-Glucoside and Its Phenolic Metabolites in Maintaining Intestinal Integrity

Cyanidin-3-glucoside (C3G) is a well-known natural anthocyanin and possesses antioxidant and anti-inflammatory properties. The catabolism of C3G in the gastrointestinal tract could produce bioactive phenolic metabolites, such as protocatechuic acid, phloroglucinaldehyde, vanillic acid, and ferulic acid, which enhance C3G bioavailability and contribute to both mucosal barrier and microbiota. To get an overview of the function and mechanisms of C3G and its phenolic metabolites, we review the accumulated data of the absorption and catabolism of C3G in the gastrointestine, and attempt to give crosstalk between the phenolic metabolites, gut microbiota, and mucosal innate immune signaling pathways.

Protocatechuic Acid-Mediated miR-219a-5p Activation Inhibits the p66shc Oxidant Pathway to Alleviate Alcoholic Liver Injury

Alcohol abuse has become common worldwide and has been recognized as a major cause of chronic alcoholic liver disease (ALD). ALD encompasses a complex process that includes a broad scope of hepatic lesions, ranging from steatosis to cirrhosis. In particular, reactive oxygen species (ROS) are mainly involved. Numerous studies have shown that p66shc plays a significant role in ALD. Protocatechuic acid (PCA), a dihydroxybenzoic acid that is naturally found in green tea, vegetables, and fruits, has efficient free radical scavenging effects. In this study, we aimed to assess the protective effect of PCA on ALD and to evaluate the microRNA- (miRNA-) p66shc-mediated reduction of ROS formation in ALD. Our results demonstrated that PCA treatment significantly decreased p66shc expression and downstream ROS formation in ALD. miR-219a-5p, which was identified by bioinformatics and experimental analysis, was enhanced by PCA and subsequently suppressed p66shc expression. Importantly, p66shc played an essential role in the protection of PCA-stimulated miR-219a-5p overexpression. Overall, these findings show that PCA-stimulated miR-219a-5p expression mitigates ALD by reducing p66shc-mediated ROS formation. This study may contribute to the development of therapeutic interventions for ALD.

ATORVASTATIN CAN PREVENT HEPATIC REMOTE REPERFUSION INJURY

Background:

Some studies have shown that statins have a promising effect on protection against reperfusion injury.

Aim:

To evaluate the ability of ischemic postconditioning, statins and both associated to prevent or minimize reperfusion injury in the liver of rats subjected to ischemia and reperfusion by abdominal aorta clamping.

Method:

Were used 41 Wistar rats, which were distributed into five groups: ischemia and reperfusion (I/R), ischemic postcondictioning (IPC), postconditioning + statin (IPC+S), statin (S) and Sham. It was performed a medium laparotomy, dissection and isolation of the infra-renal abdominal aorta; excepting Sham group, all the others were submitted to the aorta clamping for 70 min (ischemia) and posterior clamping removing (reperfusion, 70 min). In the IPC and IPC+S groups, postconditioning was performed between the ischemia and reperfusion phases by four cycles of reperfusion and ischemia lasting 30 s each. In IPC+S and S groups, preceding the surgical procedure, administration of 3.4 mg/day of atorvastatin was performed for seven days by gavage. The left hepatic lobe was removed for histological study and euthanasia was performed.

Results:

The mean hepatic injury was 3 in the I/R group, 1.5 in the IPC group, 1.2 in the IPC+S group, 1.2 in the S group, and 0 in the SHAM group. The I/R group had a higher degree of tissue injury compared to the others in the statistical analysis and there was no difference between the others (p<0.01).

Conclusion:

Ischemic postconditioning and atorvastatin were able to minimize hepatic reperfusion injury, either alone or in combination.

Ischemic Postconditioning Assessment in the Liver of Rats Undergoing Mesenteric Ischemia and Reperfusion

Introduction

Ischemic postconditioning is a method that shows evidence of efficacy in minimizing reperfusion injury; however, its effectiveness in preventing injuries in distant organs is still unknown, especially in those who have undergone mesenteric ischemia and reperfusion.

Objective

To evaluate the effect of ischemic postconditioning in preventing reperfusion injury in the liver of rats submitted to mesenteric ischemia and reperfusion, comparing two different methods of ischemic postconditioning.

Methods

30 Wistar male rats were used, distributed into three groups: Group A: Ten rats submitted to intestinal ischemia for 30 minutes followed by reperfusion for 60 minutes; Group B: Ten rats subjected to ischemia and reperfusion; after ischemia, two cycles of reperfusion (two minutes each) interleaved with two cycles of ischemia (two minutes each); and Group C: Ten rats subjected to ischemia and reperfusion; after ischemia, four cycles of reperfusion (30 seconds each) interspersed with four cycles of ischemia (30 seconds each). After the experiment, the left lobe of the liver was resected for subsequent histological analysis, using the following classification: grade 1 - centrilobular congestion; grade 2 - centrilobular congestion with some degeneration of hepatocytes in one or two central veins; and grade 3 - multifocal centrilobular congestion and degeneration of portal hepatocytes.

Results

The mean degree of liver damage found was 1.8 in group A, 1.7 in group B and 1.3 in group C. There was no statistically significant difference between the groups.

Conclusion

Ischemic postconditioning was unable to minimize reperfusion injury in rats undergoing mesenteric ischemia and reperfusion.

Protective effect of glutamine on the main and adjacent organs damaged by ischemia-reperfusion in rats

Intestinal ischemia and reperfusion (I/R) causes cellular and tissue damage to the intestine and remote organs such as the liver. Increased production of ROS and nitric oxide and dysregulation of cytoprotective enzymes may be involved in intestinal I/R. The aim was to evaluate the protective effects of glutamine on the intestine and liver of rats with intestinal I/R injury. Twenty male Wistar rats (300 g) were divided into four groups: sham-operated (SO), glutamine + SO (G + SO), I/R, and glutamine + I/R (G + I/R). Occlusion of the SMA for 30 min was followed by 15-min reperfusion. Glutamine (25 mg/kg/day) was administered once daily 24 and 48 h before I/R induction. Blood and tissue of were collected for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, histopathological analysis, immunohistochemistry of IL-1β and TNF-α, thiobarbituric acid reactive substance (TBARS) and nitric oxide, Nrf2/keap1, superoxide dismutase (SOD), NADPH quinone oxidoreductase1 (NQO1), inducible nitric oxide synthase (iNOS), heat shock protein (HSP70), glucose-regulated protein 78 (GRP78), and activating transcription factor 6 (ATF-6) by western blot. Statistic analysis by ANOVA-Student-Newman-Keuls test (mean ± SE) significantly was p < 0.05. Tissue damage, AST, ALT, IL-1β, TNF-α, TBARS, NO, Keap1, iNOS, GRP78, and ATF-6 expression were significantly lower in the G + I/R group as compared to the I/R group. Expression of Nrf2, SOD, NQO1, and HSP70, was significantly higher in the G + I/R group as compared to I/R group. Pre-treatment with glutamine provided protection against oxidative damage in the intestine and liver in an experimental model of intestinal I/R.

Sirtuins, a promising target in slowing down the ageing process

Ageing is a plastic process and can be successfully modulated by some biomedical approaches or pharmaceutics. In this manner it is possible to delay or even prevent some age-related pathologies. There are some defined interventions, which give promising results in animal models or even in human studies, resulting in lifespan elongation or healthspan improvement. One of the most promising targets for anti-ageing approaches are proteins belonging to the sirtuin family. Sirtuins were originally discovered as transcription repressors in yeast, however, nowadays they are known to occur in bacteria and eukaryotes (including mammals). In humans the family consists of seven members (SIRT1-7) that possess either mono-ADP ribosyltransferase or deacetylase activity. It is believed that sirtuins play key role during cell response to a variety of stresses, such as oxidative or genotoxic stress and are crucial for cell metabolism. Although some data put in question direct involvement of sirtuins in extending human lifespan, it was documented that proper lifestyle including physical activity and diet can influence healthspan via increasing the level of sirtuins. The search for an activator of sirtuins is one of the most extensive and robust topic of research. Some hopes are put on natural compounds, including curcumin. In this review we summarize the involvement and usefulness of sirtuins in anti-ageing interventions and discuss the potential role of curcumin in sirtuins regulation.

P66Shc-SIRT1 Regulation of Oxidative Stress Protects Against Cardio-cerebral Vascular Disease

Growing evidence shows that acute and chronic overproduction of reactive oxygen species (ROS) and increased oxidants under pathophysiologic circumstances are of vital importance in the development of cardio-cerebral vascular diseases (CCVDs). It has been revealed that the impact of ROS can be suppressed by sirtuin 1 (SIRT1), a member of the highly conserved nicotinamide adenine dinucleotide-dependent class III histone deacetylases through protecting endothelial cells from oxidative injury. Plenty of evidences indicate that p66Shc stimulates mitochondrial ROS generation through its oxidoreductase activity and plays a vital role in the pathophysiology of CCVDs. The link between SIRT and p66Shc, though not very clear yet, may be generally illustrated like this: SIRT1 negatively regulates the expression of p66Shc in transcriptional level. In this review, the authors aimed to discuss the link between the pathogenesis of CCVDs, the regulation of ROS, the interrelation between SIRT1 and p66Shc, and the protective effect of the proper regulation of p66Shc/SIRT1 on CCVDs. The imbalance between the elimination and production of ROS can lead to oxidative stress (OS). More and more evidence suggest that ROS pathological overproduction is closely connected to the genesis and growth of CCVDs. P66shc is a gene that controls ROS level, apoptosis induction, and lifespan. Lots of evidence also indicate a role for SIRT1 mediating OS responses through several ways including directly deacetylating some transcription factors that control anti-OS genes. SIRT1 downregulation can lead to a decreased deacetylation of p66shc gene promoter and can then result in p66shc transcription. SIRT1 binds to the promoter of p66Shc where it can deacetylate histone H3, which weakens the transcription and translation of p66shc.

The protective effects of curcumin on experimental acute liver lesion induced by intestinal ischemia-reperfusion through inhibiting the pathway of NF-κB in a rat model

Objective. In this study, we investigated the protective effect and mechanism of curcumin on a rat model of intestinal ischemia/reperfusion (I/R), which induces an acute liver lesion. Methods. Curcumin was injected into rats in the curcumin groups through left femoral vein. The same volume of vehicle (0.9% normal saline) was injected into sham and I/R groups. Blood and liver tissue were gathered for serological and histopathological determination. Results. Intestinal I/R led to severe liver injury manifested as a significant increase in serum AST and ALT levels; all of those were reduced by treatment with curcumin. Simultaneously, the activity of SOD in liver decreased after intestinal I/R, which was increased by curcumin treatment. On the other hand, curcumin reduced MPO activity of liver tissue, as well as serum IL-6 and TNF-α levels observably. This is in parallel with the decreased level of liver intercellular cell adhesion molecule-1 (ICAM-1) and nuclear factor-κB (NF-κB) expression. Conclusion. Our findings suggest that curcumin treatment attenuates liver lesion induced by intestinal I/R, attributable to the antioxidative and anti-inflammatory effect via inhibition of the NF-κB pathway.