p38 MAPK Endogenous Inhibition Improves Neurological Deficits in Global Cerebral Ischemia/Reperfusion Mice

A small molecule p38α MAPK inhibitor, MW150, attenuates behavioral deficits and neuronal dysfunction in a mouse model of mixed amyloid and vascular pathologies

Background

Inhibition of p38 alpha mitogen activated protein kinase (p38α) has shown great promise as a treatment for Alzheimer's disease (AD) in preclinical tests. However, previous preclinical studies were performed in "pure" models of AD pathology. A vast majority of AD patients have comorbid dementia-contributing pathologies, particularly some form of vascular damage. The present study therefore aimed to test the potential of p38α inhibition to address dysfunction in the context of comorbid amyloid and vascular pathologies.

Methods

An amyloid overexpressing mouse strain (5xFAD) was placed on an 8-week long diet to induce the hyperhomocysteinemia (HHcy) model of small vessel disease. Mice were treated with the brain-penetrant small molecule p38α inhibitor MW150 for the duration of the HHcy diet, and subsequently underwent behavioral, neuroimaging, electrophysiological, or biochemical/immunohistochemical analyses.

Results

MW150 successfully reduced behavioral impairment in the Morris Water Maze, corresponding with attenuation of synaptic loss, reduction in tau phosphorylation, and a partial normalization of electrophysiological parameters. No effect of MW150 was observed on the amyloid, vascular, or neuroinflammatory endpoints measured.

Conclusions

This study provides proof-of-principle that the inhibition of p38α is able to provide benefit even in the context of mixed pathological contributions to cognitive impairment. Interestingly, the benefit was mediated primarily via rescue of neuronal function without any direct effects on the primary pathologies. These data suggest a potential use for p38 inhibitors in the preservation of cognition across contexts, and in particular AD, either alone or as an adjunct to other AD therapies (i.e. anti-amyloid approaches). Future studies to delineate the precise neuronal pathways implicated in the benefit may help define other specific comorbid conditions amenable to this type of approach or suggest future refinement in pharmacological targeting.

Lipid nanoparticle-encapsulated lncRNA DLX6-AS1 knockdown ameliorates cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis

OBJECTIVE

Cerebral ischemia is a neurological disorder that leads to permanent disability. This research focuses on exploring the ameliorative effects of lipid nanoparticle (LNP)-encapsulated lncRNA DLX6-AS1 knockdown in cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis.

METHODS

LNP-encapsulated lncRNA DLX6-AS1 was prepared. Cerebral ischemic injury mouse models were established utilizing middle cerebral artery occlusion (MCAO). The mice were treated by intravenous injection of LNP-encapsulated lncRNA DLX6-AS1. The neurological deficits, Inflammatory factor levels, pathological characteristics were observed. In vitro N2a cell oxygen and glucose deprivation (OGD) models were established, and the cells were treated with LNP-encapsulated lncRNA DLX6-AS1 or Nrf2 inhibitor (ML385). Cell viability and apoptosis were tested. DLX6-AS1, Nrf2, HO-1, and NLRP3 expression levels were assessed.

RESULTS

LncRNA DLX6-AS1 levels were elevated in the brain tissues of mice with cerebral ischemic injury and OGD-induced N2a cells. LNP-encapsulated DLX6-AS1 siRNA (si-DLX6-AS1) improved neurological deficit scores, reduced the levels of inflammatory factors, improved brain tissue pathological damage, and raised the number of survival neurons in CA1. LNP-encapsulated si-DLX6-AS1 ameliorated the OGD-induced N2a cell viability decrease and apoptosis rate increase, and ML385 (Nrf2 inhibitor) reversed the ameliorative effects of LNP-encapsulated si-DLX6-AS1. In cerebral ischemic injury mice and OGD-induced N2a cells, Nrf2 and HO-1 levels were reduced and NLRP3 levels were increased. LNP-encapsulated si-DLX6-AS1 raised Nrf2 and HO-1 levels and reduced NLRP3 levels. Nrf2 inhibitor ML385 treatment reversed the ameliorative effects of LNP-encapsulated si-DLX6-AS1 on OGD-induced N2a cell viability and apoptosis.

CONCLUSION

Lipid nanoparticle-encapsulated si-DLX6-AS1 ameliorates cerebral ischemic injury via the Nrf2/HO-1/NLRP3 axis.

Shionone relieves oxygen-glucose deprivation/reoxygenation induced SH-SY5Y cells injury by inhibiting the p38 MAPK/NF-κB pathway

BACKGROUND

Cerebral ischemia-reperfusion injury (I/R) can affect patient outcomes and can even be life-threatening. This study aimed to explore the role of Shionone in cerebral I/R and reveal its mechanism of action through the cerebral I/R in vitro model.

METHODS

SH-SY5Y cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to induce cerebral I/R in vitro model. SH-SY5Y cells were treated with different concentrations of Shionone. Cell counting kit-8 and flow cytometry assays were used to detect cell viability and apoptosis levels. The levels of superoxide dismutase, catalase, and malondialdehyde were determined using their corresponding kits to examine the level of oxidative stress. The inflammation response was detected by IL-6, IL-1β, and TNF-α levels, using enzyme-linked-immunosorbent-assay. RT-qPCR was performed to measure the mRNA levels of p38 and NF-κB. Western blotting was used to quantify the apoptosis-related proteins and p38MAPK/NF-κB signaling pathway proteins.

RESULTS

Shionone exhibited no toxic effects on SH-SY5Y cells. Shionone inhibited OGD/R-induced cell apoptosis, improved the inflammatory response caused by OGD/R, and reduced the level of oxidative stress in cells. Western blot assay results showed that Shionone alleviated OGD/R-induced injury by inhibiting the activity of the p38 MAPK/NF-κB signaling pathway. The p38/MAPK agonist P79350 reversed the beneficial effects of Shionone.

CONCLUSION

Shionone alleviates cerebral I/R and may thus be a novel therapeutic strategy for treating cerebral I/R.

In vivo protective effects of 6‑gingerol in cerebral ischemia involve preservation of antioxidant defenses and activation of anti‑apoptotic pathways

Stroke is an important medical problem in developing countries, characterized by a sudden disruption of blood supply to the brain, either through occlusion or hemorrhage. It is a major cause of neurological impairment, resulting in high medical costs. The present study examined the effect of 6-gingerol on morphological changes, antioxidant defenses, and the anti-apoptotic factors p38 mitogen-activated protein kinase (MAPK) and mitofusin (Mfn)2, in a rat model of focal cerebral ischemia. A total of 60 healthy male Wistar rats were randomly allocated into six groups: Control, right middle cerebral artery occlusion (Rt.MCAO) + vehicle, Rt.MCAO + piracetam, and Rt.MCAO + 6-Gin 5, 10 and 20 mg/kg BW groups. The results indicated that 6-gingerol treatment for a duration of 7 days reverses morphological alterations, enhances catalase and glutathione peroxidase activities, reduces Bax, caspase-3 and MAPK expression, and increases Bcl-xL and Mfn2 expression in the cortex and hippocampus. In conclusion, 6-gingerol demonstrated significant in vivo effectiveness in mitigating pathological changes induced by cerebral ischemia. This beneficial effect is attributed, at least in part, to preservation of antioxidant defenses and activation of anti-apoptotic pathways.

Downregulation of IL-1β/p38 mitogen activated protein kinase pathway by diacerein protects against kidney ischemia/reperfusion injury in rats

Renal ischemia-reperfusion (I/R) can be precipitated by multiple clinical situations that lead to impaired renal function and associated mortality. The resulting tubular cell damage is the outcome of complex disorders including, an inflammatory process with an overproduction of cytokines. Here, diacerein (DIA), an inhibitor of proinflammatory cytokine interleukin-1 beta (IL-1β), was investigated against renal I/R in rats. DIA was orally administrated (50 mg/kg/day) for ten days before bilateral ischemia for 45 min with subsequent 2 hr. reperfusion. Interestingly, DIA alleviated the renal dysfunction and histopathological damage in the renal tissues. Pretreatment with DIA corrected the oxidative imbalance by prevented reduction in antioxidant levels of GSH and SOD, while it decreased the elevation of the oxidative marker, MDA. In addition, DIA downregulated IL-1β and TNF-α expression in the renal tissues. Consequent to inhibition of the oxidative stress and inflammatory cascades, DIA inhibited the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK). Therefore, downstream targets for p38 MAPK were also inhibited via DIA which prevented further increases of inflammatory cytokines and the apoptotic marker, caspase-3. Collectively, this study revealed the renoprotective role of DIA for renal I/R and highlighted the role of p38 MAPK encountered in its therapeutic application in renal disease.

Compound musk injection in the treatment of ischemic stroke: A network analysis of the mechanism of action

BACKGROUND

Ischemic stroke (IS) is affected by a wide range of factors and has certain treatment limitations. Studies have reported that compound musk injection (CMI) is effective in the treatment of IS, however, its mechanism of action is still unclear.

METHODS

The main active ingredients in CMI were retrieved from HERB, TCMSP and BATMAN databases, and the relevant targets were predicted by Swiss Target Prediction platform. MalaCards, OMIM, DrugBank, DisGeNET, Genecards and TTD databases were used to obtain the genes related to IS. The intersection of drugs and disease targets was used to construct protein-protein interaction networks, and gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed. AutoDock Vina software was used for molecular docking, and cell experiments were conducted to verify the results. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression level of relative mRNA in cells.

RESULTS

Network analysis and molecular docking results showed that the key targets of CMI in the treatment of IS were SRC, TP53, PIK3R1, MAPK3, PIK3CA, MAPK1, etc. KEGG pathway enrichment analysis mainly involved PI3K/Akt signaling pathway, Rap1 signaling pathway and MAPK signaling pathway. The molecular docking results all showed that the key ingredients were strong binding activity with the key targets. The quantitative RT-PCR results indicated that CMI may increase the expression of PIK3CA, MAPK3 mRNA and decrease the expression of SRC mRNA.

CONCLUSIONS

CMI can treat IS by regulating pathways and targets related to inflammatory response and apoptosis in a multi-component manner.

Role of SIRT1 in sepsis-induced encephalopathy: Molecular targets for future therapies

Sepsis induces neuroinflammation, BBB disruption, cerebral hypoxia, neuronal mitochondrial dysfunction, and cell death causing sepsis-associated encephalopathy (SAE). These pathological consequences lead to short- and long-term neurobehavioural deficits. Till now there is no specific treatment that directly improves SAE and its associated behavioural impairments. In this review, we discuss the underlying mechanisms of sepsis-induced brain injury with a focus on the latest progress regarding neuroprotective effects of SIRT1 (silent mating type information regulation-2 homologue-1). SIRT1 is an NAD+ -dependent class III protein deacetylase. It is able to modulate multiple downstream signals (including NF-κB, HMGB, AMPK, PGC1α and FoxO), which are involved in the development of SAE by its deacetylation activity. There are multiple recent studies showing the neuroprotective effects of SIRT1 in neuroinflammation related diseases. The proposed neuroprotective action of SIRT1 is meant to bring a promising therapeutic strategy for managing SAE and ameliorating its related behavioural deficits.

Revisiting p38 Mitogen-Activated Protein Kinases (MAPK) in Inflammatory Arthritis: A Narrative of the Emergence of MAPK-Activated Protein Kinase Inhibitors (MK2i)

The p38 mitogen-activated protein kinase (p38-MAPK) is a crucial signaling pathway closely involved in several physiological and cellular functions, including cell cycle, apoptosis, gene expression, and responses to stress stimuli. It also plays a central role in inflammation and immunity. Owing to disparate p38-MAPK functions, it has thus far formed an elusive drug target with failed clinical trials in inflammatory diseases due to challenges including hepatotoxicity, cardiac toxicity, lack of efficacy, and tachyphylaxis, which is a brief initial improvement with rapid disease rebound. To overcome these limitations, downstream antagonism of the p38 pathway with a MAPK-activated protein kinase (MAPKAPK, also known as MK2) blockade has demonstrated the potential to abrogate inflammation without the prior recognized toxicities. Such MK2 inhibition (MK2i) is associated with robust suppression of key pro-inflammatory cytokines, including TNFα and IL-6 and others in experimental systems and in vitro. Considering this recent evidence regarding MK2i in inflammatory arthritis, we revisit the p38-MAPK pathway and discuss the literature encompassing the challenges of p38 inhibitors with a focus on this pathway. We then highlight how novel MK2i strategies, although encouraging in the pre-clinical arena, may either show evidence for efficacy or the lack of efficacy in emergent human trials data from different disease settings.