Knockdown of IL-32 protects PC12 cells against oxygen-glucose deprivation/reoxygenation-induced injury via activation of Nrf2/NF-κB pathway

Crosstalk between Nrf2 signaling pathway and inflammation in ischemic stroke: Mechanisms of action and therapeutic implications

One of the major causes of long-term disability and mortality is ischemic stroke that enjoys limited treatment approaches. On the one hand, oxidative stress, induced by excessive generation of reactive oxygen species (ROS), plays a critical role in post-stroke inflammatory response. Increased ROS generation is one of the basic factors in the progression of stroke-induced neuroinflammation. Moreover, intravenous (IV) thrombolysis using recombinant tissue plasminogen activator (rtPA) as the only medication approved for patients with acute ischemic stroke who suffer from some clinical restrictions it could not cover the complicated episodes that happen after stroke. Thus, identifying novel therapeutic targets is crucial for successful preparation of new medicines. Recent evidence indicates that the transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2) contributes significantly to regulating the antioxidant production in cytosol, which causes antiinflammatory effects on neurons. New findings have shown a relationship between activation of the Nrf2 and glial cells, nuclear factor kappa B (NF-κB) pathway, the nucleotide-binding domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling, and expression of inflammatory markers, suggesting induction of Nrf2 activation can represent a promising therapeutic alternative as the modulators of Nrf2 dependent pathways for targeting inflammatory responses in neural tissue. Hence, this review addresses the relationship of Nrf2 signaling with inflammation and Nrf2 activators' potential as therapeutic agents. This review helps to improve required knowledge for focused therapy and the creation of modern and improved treatment choices for patients with ischemic stroke.

The protection impact of tectoridin on PC12 cell preventing OGD/R-caused damage through PI3K/AKT signaling channel

The present work examined the effect exerted by tectoridin preventing oxygen glucose deprivation/reoxygenation (OGD/R) damage within PC12 cell. We incubated PC12 cells with Na₂S₂O₄ (10 mM) for 2 h, and tectoridin at different concentrations was then added; based on methyl-thiazolyl-tetrazolium (MTT) and lactate dehydrogenase (LDH) tests, the protection impact was tested. 2',7'-dicholorofluorescein diacetate (DCFH-DA), Fluo-3AM, and 5, 5', 6, 6' -tetrachloro-1, 1', 3, 3' -tetraethyl-imidacarbocyanine iodide (JC-1) staining, and Western blotting were used for determining reactive oxygen species (ROS) level, intracellular Ca²⁺ content, mitochondrial membrane potential (MMP) and the related proteins contents. As a result, tectoridin could improve the cell viability and inhibit the release of LDH. In-depth studies demonstrated that tectoridin limited the overproduction of ROS and intracellular Ca²⁺ content and increased MMP, which showed a close association with ROS-mediated mitochondrial function. Moreover, tectoridin hindered apoptosis based on the up-regulation of the expressions of p-AKT, Bcl-2/Bax and p-mTOR. Furthermore, the level of Nrf2 was also improved by treatment of tectoridin. In addition, the expression of Bcl-2/Bax, p-Akt, p-mTOR, Nrf2, HO-1, NQO1 and GCLM were reduced by LY294002 and the protective role of tectoridin was limited by LY294002. The results unambiguously suggested that tectoridin reduced OGD/R-caused damage to PC12 cells and might ensure neuroprotection by stimulating the PI3K/AKT signaling channel.

Interleukins and Ischemic Stroke

Ischemic stroke after cerebral artery occlusion is one of the major causes of chronic disability worldwide. Interleukins (ILs) play a bidirectional role in ischemic stroke through information transmission, activation and regulation of immune cells, mediating the activation, multiplication and differentiation of T and B cells and in the inflammatory reaction. Crosstalk between different ILs in different immune cells also impact the outcome of ischemic stroke. This overview is aimed to roughly discuss the multiple roles of ILs after ischemic stroke. The roles of IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-16, IL-17, IL-18, IL-19, IL-21, IL-22, IL-23, IL-32, IL-33, IL-34, IL-37, and IL-38 in ischemic stroke were discussed in this review.

APPL1 ameliorates myocardial ischemia‑reperfusion injury by regulating the AMPK signaling pathway

Myocardial ischemia-reperfusion injury results in elevated reactive oxygen species (ROS) production and causes oxidative stress damage. Therefore, the current study aimed to investigate whether adaptor protein phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) could induce the expression of antioxidant enzymes through AMP-activated protein kinase (AMPK) signaling in order to alleviate the injury caused by ischemia/hypoxia-reperfusion. Following induction of hypoxia-reoxygenation (H/R) injury in H9c2 cells, the liver kinase B1 (LKB1)/AMPK/acetyl-CoA carboxylase α (ACC) signaling pathway was investigated using western blot analysis, along with the detection of superoxide dismutase (SOD)2 and SOD3 expression. Additionally, cell viability was detected using a Cell Counting Kit-8 assay and ROS production was analyzed using ROS staining, whereas the expression levels of inflammatory mediators (TNF-α, monocyte chemoattractant protein 1 and IL-1β), apoptosis mediators [cleaved caspase-3, cleaved poly (ADP-ribose) polymerase and Bcl-2] and nuclear factor erythroid 2-related factor 2 signaling pathway-related proteins were detected via western blot analysis following overexpression of APPL1 alone or in combination with compound C treatment (an AMPK inhibitor). The results indicated that H/R induction upregulated the phosphorylation levels of LKB1, AMPK and ACC, and decreased the expression levels of APPL1 and SOD enzyme activities. APPL1 overexpression increased the phosphorylation levels of LKB1, AMPK and ACC, SOD enzyme activity and cell viability whereas the expression levels of proinflammatory mediators and proapoptotic mediators, and the levels of ROS production were markedly decreased when compared with H/R group with empty plasmid transfection. APPL overexpression-mediated effects were significantly abrogated by compound C. Taken together, the data indicated that APPL1 inhibited ROS production and H/R-induced myocardial injury via the AMPK signaling pathway. Therefore, APPL1 may serve as a potential therapeutic target for myocardial H/R injury.

Interleukin 32: A novel player in perioperative neurocognitive disorders

Perioperative neurocognitive disorders (PND) are highly prevalent after surgery, especially in aged patients. PND results in long-term morbidity and mortality with unclear pathophysiologic mechanisms. As a key hallmark of PND, surgery-induced neuroinflammation resulted from the invading of exogenous tracers into the cerebral parenchyma, causing hippocampal neuroinflammation and cognitive impairment. IL-32, with different isoforms, played a significant regulatory role in various inflammatory diseases. Its prevalence in peripheral circulating blood was closely associated with the central nervous system (CNS) diseases. Beyond that, specific subtype of IL-32 was reported to involve in the neuroinflammation regulation in cerebral ischemia impairment, multiple sclerosis, Alzheimer's Disease, and so on. Thus, we speculate that IL-32 may participate in the regulation of the surgery-induced neuroinflammation during the parthenogenesis of PND. The isoforms, spatio-temporal regulation of IL-32 may determine its pro- or anti-inflammation properties in parthenogenesis of PND. Therefore, IL-32 could be a putative therapeutic target for the prevention and reversal of PND in the future.