Suppression of the p66shc adapter protein by protocatechuic acid prevents the development of lung injury induced by intestinal ischemia reperfusion in mice

Chronic Gastric Ulcer Healing Actions of the Aqueous Extracts of Staple Plant Foods of the North-West, Adamawa, and West Regions of Cameroon

Aim

This study is aimed at establishing phenolic compound profile and assessing the possible antiulcer activities of aqueous extracts of some staple plant foods from the West and North-West regions of Cameroon against chronic gastric ulcer models in rats.

Materials and Methods

Phenolic constituents of extracts were evaluated using HPLC-DAD. Aqueous extracts of Corchorus olitorius, Solanum nigrum, Vigna unguiculata, Triumfetta pentandra, "nkui" spices, and "yellow soup" spices were tested at two doses (200 and 400 mg/kg). After treatments, animals were sacrificed, healing percentage and antioxidant status (catalase, superoxide dismutase, and glutathione peroxidase) were evaluated, and histological examination of gastric mucosa was realized.

Results

HPLC-DAD revealed that p-hydroxybenzoic and protocatechuic acids were the phenolic compound present in all extracts. Oral administration of extracts (200 and 400 mg/kg) significantly reduced ulcer surface value and significantly increased mucus production compared to the control groups (p < 0.05). Histological study supported the observed healing activity of different extracts characterized by a reduced inflammatory response. Moreover, administration of aqueous extracts increased the activity of antioxidant enzymes.

Conclusion

This study revealed that aqueous extracts of Solanum nigrum, Corchorus olitorius, Vigna unguiculata, Triumfetta pentandra, "yellow soup" spices, and "nkui" spices possess healing antiulcer effects against models of gastric ulcers. The antiulcer mechanisms involved may include increase of gastric mucus production and improvement of the antioxidant activity of gastric tissue. These activities may be due to the phenolic compounds identified in the extracts, especially p-hydroxybenzoic and protocatechuic acids present in all extracts and with known antioxidant, cytoprotective, and healing properties. However, all the diets may promote the healing process of chronic ulcers caused by excessive alcohol consumption/stress.

Dietary intake of cyanidin-3-glucoside induces a long-lasting cardioprotection from ischemia/reperfusion injury by altering the microbiota

The anthocyanin class of flavonoids, including cyanidin-3-glucoside (C3G) present in berries, blood oranges and pigmented cereal crops, are food bioactives with antioxidant and anti-inflammatory action, capable to reduce myocardial ischemia/reperfusion (I/R) injury by unclear mechanism. Assessing the value of sporadic beneficial diet is critical for practical application. We aimed to determine whether and how the cardioptotective effect of dietary intake of anthocyanins persists. Gene expression, histology and resistance to I/R were investigated ex vivo in hearts from mice after a month beyond the cease of the C3G-enriched diet. Cardiac injury, oxidative stress and mitochondrial damage following I/R was effectively reduced in mice fed C3G-enriched diet, even after a month of wash out with standard diet. Cardioprotection was observed also in immune-deficient mice lacking mature B and T cells indicating the anti-inflammatory activity of C3G was not involved. Moreover, the transcription reprogramming induced by the C3G-enriched diets was rescued by the wash out treatment. Instead, we found C3G-enriched diet changed the microbiome and the transplantation of the fecal microbiota transferred the cardioprotection from mice fed C3G-enriched diet to mice fed standard diet. These findings established the effect of C3G dietary intake on gut microbiota determines long lasting cardioprotection.

Cellular Signal Transduction Pathways Involved in Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (II/R) injury is a common type of tissue and organ injury, secondary to intestinal and mesenteric vascular diseases. II/R is characterized by a high incidence rate and mortality. In the II/R process, intestinal barrier function is impaired and bacterial translocation leads to excessive reactive oxygen species, inflammatory cytokine release, and even apoptosis. A large number of inflammatory mediators and oxidative factors are released into the circulation, leading to severe systemic inflammation and multiple organ failure of the lung, liver, and kidney. Acute lung injury (ALI) is the most common complication, which gradually develops into acute respiratory distress syndrome and is the main cause of its high mortality. This review summarizes the signal transduction pathways and key molecules in the pathophysiological process of ALI induced by II/R injury and provides a new therapeutic basis for further exploration of the molecular mechanisms of ALI induced by II/R injury. In particular, this article will focus on the biomarkers involved in II/R-induced ALI.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

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.

Carnosic Acid Mitigates Early Brain Injury After Subarachnoid Hemorrhage: Possible Involvement of the SIRT1/p66shc Signaling Pathway

Carnosic acid (CA) has been reported to exhibit a variety of bioactivities including antioxidation, neuroprotection, and anti-inflammation; however, the impact of CA on subarachnoid hemorrhage (SAH) has never been elucidated. The current study was undertaken to explore the role of CA in early brain injury (EBI) secondary to SAH and the underlying mechanisms. Adult male Sprague-Dawley rats were perforated to mimic a clinical aneurysm with SAH. CA or vehicle was administered intravenously immediately after the SAH occurred. Mortality, SAH grade, neurologic function scores, brain water content, Evans blue extravasation, and the levels of reactive oxygen species (ROS) levels in the ipsilateral cortex were determined 24 h after the SAH occurred. Western blot, immunofluorescence, Fluoro-Jade C (FJC) and TUNEL staining were also performed. Our results showed that CA decreased ROS levels, alleviated brain edema and blood-brain barrier permeability, reduced neuronal cell death, and promoted neurologic function improvement. To probe into the potential mechanisms. We showed that CA increased SIRT1, MnSOD, and Bcl-2 expression, as well as decreased p66shc, Bax, and cleaved caspase-3 expression. Interestingly, sirtinol, a selective inhibitor of SIRT1, abolished the anti-apoptotic effects of CA. Taken together, these data revealed that CA has a neuroprotective role in EBI secondary to SAH. The potential mechanism may involve suppression of neuronal apoptosis through the SIRT1/p66shc signaling pathway. CA may provide a promising therapeutic regimen for management of SAH.

Interleukin‑6 RNA knockdown ameliorates acute lung injury induced by intestinal ischemia reperfusion in rats by upregulating interleukin‑10 expression

Acute lung injury (ALI) is a common complication following intestinal ischemia/reperfusion (II/R) injury and contributes to the associated high mortality rate. However, the underlying mechanism is poorly understood and treatments are limited. RNA interference (RNAi) has been demonstrated to provide a promising disease treatment strategy both in vitro and in vivo. Therefore, the present study aimed to test whether blocking the proinflammatory cytokine IL‑6 by RNAi may protect the lungs from remote organ injury following II/R, and to investigate the potential underlying mechanisms. A total of 176 adult healthy male Sprague‑Dawley rats were randomly divided into sham, II/R, negative‑control and IL‑6‑short hairpin (sh)RNA groups. The rats underwent II/R injury with occlusion of the superior mesenteric artery and coeliac artery to induce ischemia for 40 min, and were subsequently reperfused for 0‑48 h. The negative‑control group received a control lentiviral vector containing scrambled or non‑specific sequences, and the IL‑6‑shRNA groups were administered with a vector containing an IL‑6 shRNA sequence to affect RNAi‑mediated knockdown of IL‑6. ALI severity was determined by lung edema (lung wet/dry ratio) and histological analysis (lung injury scores). IL‑6 localization, and mRNA and protein expression levels, were detected by immunofluorescence, reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. IL‑10 expression induced by IL‑6 knockdown in lung tissues was additionally detected. IL‑6 RNAi was revealed to significantly reduce the expression of IL‑6, which was associated with upregulated IL‑10 expression in lung tissues. Consequently, the severities of ALI and edema induced by II/R were substantially improved. In conclusion, the present study demonstrated that IL‑6 RNAi may protect the lung from ALI induced by II/R, and that this protective role may be associated with upregulation of IL‑10. These findings may contribute to the development of an IL‑6‑RNAi‑based therapeutic strategy for the treatment of II/R‑induced ALI.

Induced pluripotent stem cells alleviate lung injury from mesenteric ischemia-reperfusion

BACKGROUND

Mesenteric ischemia-reperfusion (I/R) injury is a serious pathophysiologic process that can trigger the development of multiorgan dysfunction. Acute lung injury is a major cause of death among mesenteric I/R patients, as current treatments remain inadequate. Stem cell-based therapies are considered novel strategies for treating several devastating and incurable diseases. This study examined whether induced pluripotent stem cells (iPSCs) lacking c-myc (i.e., induced using only the three genes oct4, sox2, and klf4) can protect against acute lung injury in a mesenteric I/R mouse model.

METHODS

C57BL/6 mice were randomly divided into the following groups: sham/no treatment, vehicle treatment with phosphate-buffered saline, treatment with iPSCs, and treatment with iPSC-conditioned medium. The mice were subjected to mesenteric ischemia for 45 minutes followed by reperfusion for 24 hours. After I/R, the lungs and the ileum of the mice were harvested. Lung injury was evaluated by histology, immunohistochemistry, and analyses of the levels of inflammatory cytokines, cleaved caspase 3, and 4-hydroxynonenal.

RESULTS

The intravenously delivered iPSCs engrafted to the lungs and the ileum in response to mesenteric I/R injury. Compared with the phosphate-buffered saline-treated group, the iPSC-treated group displayed a decreased intensity of acute lung injury 24 hours after mesenteric I/R. iPSC transplantation significantly reduced the expression of proinflammatory cytokines, oxidative stress markers, and apoptotic factors in injured lung tissue and remarkably enhanced endogenous alveolar cell proliferation. iPSC-conditioned medium treatment exerted a partial effect compared with iPSC treatment.

CONCLUSION

When considering the anti-inflammatory, antioxidant, and antiapoptotic properties of iPSCs, the transplantation of iPSCs may represent an effective treatment option for mesenteric I/R-induced acute lung injury.

Protective effects of icariin-mediated SIRT1/FOXO3 signaling pathway on intestinal ischemia/reperfusion-induced acute lung injury

Acute lung injury (ALI) is a common complication following intestinal ischemia/reperfusion (I/R) and is a major contributing factor to its high mortality rate. Sirtuin 1 (SIRT1), a NAD+-dependent deacetylase, has been reported to have an important role in apoptosis inhibition, oxidative stress resistance and cell lifespan extension through its deacetylation of forkhead box protein O3 (FOXO3). It has been demonstrated that icariin (ICA), a flavonoid extracted from Epimedium, upregulates SIRT1 expression. The aim of the present study was to examine whether ICA-mediated SIRT1/FOXO3 signaling pathway activation had a protective effect on intestinal I/R-induced ALI. The effects of ICA on intestinal I/R-induced ALI and its regulation of the SIRT1/FOXO3 signaling pathway on intestinal I/R-induced ALI were investigated in rats. The results demonstrated that ICA pretreatment markedly reduced intestinal I/R-induced ALI as indicated by histological alterations, including decreased tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), reduced oxidative stress, acetylated FOXO3 and B-cell lymphoma 2 (Bcl-2)-interacting mediator of cell death levels, and increased glutathione (GSH), GSH peroxidase, SIRT1, manganese superoxide dismutase and Bcl-2 levels in rat lung tissues. Furthermore, ICA pretreatment upregulated SIRT1 expression, which then downregulated FOXO3 acetylation. In conclusion, ICA exhibited significant protective effects in intestinal I/R-induced ALI. The protective effect of ICA may be attributed to the upregulation of SIRT1, which contributed to FOXO3 deacetylation and the modulation of downstream antioxidative and anti-apoptotic factors.

Protocatechuic acid, a novel active substance against avian influenza virus H9N2 infection

Influenza virus H9N2 subtype has triggered co-infection with other infectious agents, resulting in huge economical losses in the poultry industry. Our current study aims to evaluate the antiviral activity of protocatechuic acid (PCA) against a virulent H9N2 strain in a mouse model. 120 BALB/c mice were divided into one control group, one untreated group, one 50 mg/kg amantadine hydrochloride-treated group and three PCA groups treated 12 hours post-inoculation with 40, 20 or 10 mg/kg PCA for 7 days. All the infected animals were inoculated intranasally with 0.2 ml of a A/Chicken/Hebei/4/2008(H9N2) inoculum. A significant body weight loss was found in the 20 mg/kg and 40 mg/kg PCA-treated and amantadine groups as compared to the control group. The 14 day survivals were 94.4%, 100% and 95% in the PCA-treated groups and 94.4% in the amantadine hydrochloride group, compared to less than 60% in the untreated group. Virus loads were less in the PCA-treated groups compared to the amantadine-treated or the untreated groups. Neutrophil cells in BALF were significantly decreased while IFN-γ, IL-2, TNF-α and IL-6 decreased significantly at days 7 in the PCA-treated groups compared to the untreated group. Furthermore, a significantly decreased CD4+/CD8+ ratio and an increased proportion of CD19 cells were observed in the PCA-treated groups and amantadine-treated group compared to the untreated group. Mice administered with PCA exhibited a higher survival rate and greater viral clearance associated with an inhibition of inflammatory cytokines and activation of CD8+ T cell subsets. PCA is a promising novel agent against bird flu infection in the poultry industry.

Pretreatment with mineralocorticoid receptor blocker reduces intestinal injury induced by ischemia and reperfusion: involvement of inhibition of inflammatory response, oxidative stress, nuclear factor κB, and inducible nitric oxide synthase

BACKGROUND

Spironolactone (Sp), a mineralocorticoid receptor antagonist, protects against the ischemia reperfusion (IR) injury of retina, kidney, heart, and brain. We aimed to investigate the effects of Sp on intestinal IR injury.

METHODS

Male Wistar rats were randomly divided into: (1) a sham control group; (2) an IR control group, subjected to 30 min ischemia and 3 h reperfusion; (3) a group treated with Sp (20 mg/kg) for 3 d before the IR; and (4) a sham-operated control group treated with Sp (20 mg/kg). After the reperfusion, blood and intestinal tissue samples were collected to evaluate histopathologic state, neutrophil infiltration (by measuring myeloperoxidase activity), levels of the cytokines (tumor necrosis factor α, interleukin 1α [IL-1α], interferon γ, monocyte chemotactic protein-1, granulocyte macrophage-colony stimulating factor, and IL-4), malondialdehyde (MDA) and reduced glutathione contents, and immunohistochemical expressions of nuclear factor κB, inducible nitric oxide synthase (iNOS), and caspase-3.

RESULTS

MDA content, myeloperoxidase activity, and plasma levels of tumor necrosis factor α, IL-1α, and monocyte chemotactic protein-1 were all elevated in IR, indicating the oxidative stress and local and systemic inflammatory response. Sp administration markedly reduced the MDA content and the cytokine levels. The pretreatment alleviated intestinal injury, neutrophil infiltration, and the expressions of caspase-3, iNOS, and NFκB.

CONCLUSIONS

The results implicate that Sp may have a strong protective effect against the intestinal IR injury. The effect can be mediated via suppression of both systemic inflammatory response and apoptosis through amelioration of oxidative stress and generation of proinflammatory cytokines, iNOS, caspase-3, and nuclear factor κB. Therefore, mineralocorticoid receptor antagonism might be of potential therapeutic benefit in cases of intestinal IR damage.

Blockade of PKCβ protects against remote organ injury induced by intestinal ischemia and reperfusion via a p66shc-mediated mitochondrial apoptotic pathway

Intestinal ischemia-reperfusion (I/R) is a serious clinical dilemma with high morbidity and mortality. Remote organ damage, especially acute lung injury and liver injury are common complications that contribute to the high mortality rate. We previously demonstrated that activation of PKCβII is specifically involved in the primary injury of intestinal I/R. Considering the tissue-specific features of PKC activation, we hypothesized that some kind of PKC isoform may play important roles in the progression of secondary injury in the remote organ. Mice were studied in in vivo model of intestinal I/R. The activation of PKC isoforms were screened in the lung and liver. Interestingly, we found that PKCβII was also activated exclusively in the lung and liver after intestinal I/R. PKCβII suppression by a specific inhibitor, LY333531, significantly attenuated I/R-induced histologic damage, inflammatory cell infiltration, oxidative stress, and apoptosis in these organs, and also alleviated systemic inflammation. In addition, LY333531 markedly restrained p66shc activation, mitochondrial translocation, and binding to cytochrome-c. These resulted in the decrease of cytochrome-c release and caspase-3 cleavage, and an increase in glutathione and glutathione peroxidase. These data indicated that activated PKC isoform in the remote organ, specifically PKCβII, is the same as that in the intestine after intestinal I/R. PKCβII suppression protects against remote organ injury, which may be partially attributed to the p66shc-cytochrome-c axis. Combined with our previous study, the development of a specific inhibitor for prophylaxis against intestinal I/R is promising, to prevent multiple organ injury.

Fish-oil emulsion (omega-3 polyunsaturated fatty acids) attenuates acute lung injury induced by intestinal ischemia-reperfusion through Adenosine 5'-monophosphate-activated protein kinase-sirtuin1 pathway

BACKGROUND

Activated macrophage infiltration into the lungs is paramount in the pathogenesis of acute lung injury (ALI) induced by intestinal ischemia-reperfusion (I/R). Omega-3 polyunsaturated fatty acid (ω-3 PUFA) is a potent activator of the Adenosine 5'-monophosphate-activated protein kinase-sirtuin1 (AMPK/SIRT1) pathway against macrophage inflammation. We aimed to evaluate whether ω-3 PUFAs may protect against ALI induced by intestinal I/R via the AMPK/SIRT1 pathway.

METHODS

Ischemia in male Wistar rats was induced by superior mesenteric artery occlusion for 60 min and reperfusion for 240 min. One milliliter per day of fish-oil emulsion (FO emulsion, containing major ingredients as ω-3 PUFAs) or normal saline (control) was administered by intraperitoneal injection for three consecutive days to each animal. All animals were sacrificed at the end of reperfusion. Blood and tissue samples were collected for analysis.

RESULTS

Intestinal I/R caused intestinal and lung injury, evidenced by severe lung tissue edema and macrophage infiltration. Pretreatment with FO emulsion improved the integrity of microscopic structures in the intestine and lungs. Intestinal I/R induced the expression of macrophage-derived mediators (macrophage migration inhibitory factor and macrophage chemoattractant protein-1), inflammatory factors (nuclear factor κB, tumor necrosis factor α, interleukin 6, and interleukin 1β), and proapoptosis factor p66shc. There was a decrease in the expression of AMPK, SIRT1, and claudin 5. FO emulsion significantly inhibited macrophage infiltration into the lungs, inflammatory factor expression, and p66shc phosphorylation. Importantly, FO emulsion restored AMPK, SIRT1, and claudin 5 in the lungs.

CONCLUSIONS

Pretreatment with ω-3 PUFAs effectively protects intestinal and lung injury induced by intestinal I/R, reduces macrophage infiltration, suppresses inflammation, inhibits lung apoptosis, and improves the lung endothelial barrier after intestinal I/R in a manner dependent on AMPK/SIRT1. Thus, there is a potential for developing AMPK/SIRT1 as a novel target for patients with intestinal I/R-induced ALI.