Endothelial-specific insulin receptor substrate-1 overexpression worsens neonatal hypoxic-ischemic brain injury via mTOR-mediated tight junction disassembly

The lncRNA lnc_AABR07044470.1 promotes the mitochondrial-damaged inflammatory response to neuronal injury via miR-214-3p/PERM1 axis in acute ischemic stroke

PURPOSE

We investigated the role of lnc_AABR07044470.1 on the occurrence and development of acute ischemic stroke (AIS) and neuronal injury by targeting the miR-214-3p/PERM1 axis to find a novel clinical drug target and prediction and treatment of AIS.

METHODS

The mouse AIS animal model was used in vivo experiments and hypoxia/reoxygenation cell model in vitro was established. Firstly, infarction volume and pathological changes of mouse hippocampal neurons were detected using HE staining. Secondly, rat primary neuron apoptosis was detected by flow cytometry assay. The numbers of neuron, microglia and astrocytes were detected using immunofluorescence (IF). Furthermore, binding detection was performed by bioinformatics database and double luciferase reporter assay. Lnc_AABR07044470.1 localization was performed using fluorescence in situ hybridization (FISH).Lnc_AABR07044470.1, miR-214-3pand PERM1mRNA expression was performed using RT-qPCR. NLRP3, ASC, Caspase-1 and PERM1 protein expression was performed using Western blotting. IL-1β was detected by ELISA assay.

RESULTS

Mouse four-vessel occlusion could easily establish the animal model, and AIS animal model had an obvious time-dependence. HE staining showed that, compared with the sham group, infarction volume and pathological changes of mouse hippocampal neurons were deteriorated in the model group. Furthermore, compared with the sham group, neurons were significantly reduced, while microglia and astrocytes were significantly activated. Moreover, the bioinformatics prediction and detection of double luciferase reporter confirmed the binding site of lnc_AABR07044470.1 to miR-214-3p and miR-214-3p to Perm1. lnc_AABR07044470.1 and PERM1 expression was significantly down-regulated and miR-214-3pexpression was significantly up-regulated in AIS animal model in vivo. At the same time, the expression of inflammasome NLRP3, ASC, Caspase-1 and pro-inflammatory factor IL-1β was significantly up-regulated in vivo and in vitro. The over-expression of lnc_AABR07044470.1 and miR-214-3p inhibitor could inhibit the neuron apoptosis and the expression of inflammasome NLRP3, ASC, Caspase-1 and pro-inflammatory factor IL-1β and up-regulate the expression of PERM1 in vitro. Finally, over-expression of lnc_AABR07044470.1 and miR-214-3p inhibitor transfected cell model was significant in relieving the AIS and neuronal injury.

CONCLUSION

Lnc_AABR07044470.1 promotes inflammatory response to neuronal injury via miR-214-3p/PERM1 axis in AIS.

DADLE promotes motor function recovery by inhibiting cytosolic phospholipase A2 mediated lysosomal membrane permeabilization after spinal cord injury

BACKGROUND AND PURPOSE

Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D-Ala2 , D-Leu5 ]-enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI.

EXPERIMENTAL APPROACH

Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg-1 ) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways.

KEY RESULTS

DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA2 , overexpression of cPLA2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway.

CONCLUSION AND IMPLICATION

DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA2 pathway.

Ginsenoside compound K reduces ischemia/reperfusion-induced neuronal apoptosis by inhibiting PTP1B-mediated IRS1 tyrosine dephosphorylation

Background

Ginsenoside compound K (CK) stimulated activation of the PI3K-Akt signaling is one of the major mechanisms in promoting cell survival after stroke. However, the underlying mediators remain poorly understood. This study aimed to explore the docking protein of ginsenoside CK mediating the neuroprotective effects.

Materials and methods

Molecular docking, surface plasmon resonance, and cellular thermal shift assay were performed to explore ginsenoside CK interacting proteins. Neuroscreen-1 cells and middle cerebral artery occlusion (MCAO) model in rats were utilized as in-vitro and in-vivo models.

Results

Ginsenoside CK interacted with recombinant human PTP1B protein and impaired its tyrosine phosphatase activity. Pathway and process enrichment analysis confirmed the involvement of PTP1B and its interacting proteins in PI3K-Akt signaling pathway. PTP1B overexpression reduced the tyrosine phosphorylation of insulin receptor substrate 1 (IRS1) after oxygen-glucose deprivation/reoxygenation (OGD/R) in neuroscreen-1 cells. These regulations were confirmed in the ipsilateral ischemic hemisphere of the rat brains after MCAO/R. Ginsenoside CK treatment reversed these alterations and attenuated neuronal apoptosis.

Conclusion

Ginsenoside CK binds to PTP1B with a high affinity and inhibits PTP1B-mediated IRS1 tyrosine dephosphorylation. This novel mechanism helps explain the role of ginsenoside CK in activating the neuronal protective PI3K-Akt signaling pathway after ischemia-reperfusion injury.

Interactions of alcohol and combination antiretroviral (cART) drug in diabetic male Sprague Dawley rats: Hippocampal perturbations and toxicosis

Hippocampal pathology in diabetes is constantly investigated but the resultant health impact of the concomitant presence of alcohol and combined antiretroviral therapy (cART) in diabetes requires further studies to delineate toxicities inimical to hippocampal normal function. Forty-eight male Sprague Dawley rats were divided into eight groups (n = 6): negative control (NC), alcohol (AL), cART (AV), alcohol-cART (AA), diabetic control (DB), diabetes-alcohol (DAL), diabetes-cART (DAV), and diabetes-alcohol-cART (DAA) exposure groups. Following diabetes induction and sub-chronic (90 days) treatment exposure, hippocampal homogenates were profiled for pro-inflammatory cytokines and oxidative stress (MDA and GPx) using immunoassay, while apoptotic genes (BAX, Bcl₂, and Caspase-3), insulin receptor genes (INSR and IRS-1), and blood-brain barrier (BBB) junctional proteins (claudin-5, and occludin) gene expression were assessed using qPCR. Histomorphology of hippocampal neuronal number, nuclei area, and volume of dentate gyrus and neurogenesis were accessed using Giemsa stain, Ki67, and DCX histochemistry respectively. A central hippocampal effect that underpins all treatments is the reduction of DG neuronal number and antioxidant (GPx), highlighting the venerability of the hippocampal dentate gyrus neurons to diabetes, alcohol, cART, and their combinatorial interactions. Additionally, elevated BAX, Bcl_2, and IRS1 mRNA levels in the DAL group, and their downregulation in AA, suggests IRS-1-regulated apoptosis due to differential modulating effects of alcohol treatment in diabetes (DAL) in contrast to alcohol with cART (AA). Although the interaction in AA therapy ameliorated the independent alcohol and cART effects on MDA levels, pro-inflammatory cytokines, and DCX, the interaction in AA exacerbated a deficiency in the expression of INSR, IRS-1 (insulin sensitivity), and BBB mRNA which are implicated in the pathogenies of diabetes. Furthermore, the diabetic comorbidity groups (DAV, DAL, and DAA) all share a central effect of elevated hippocampal oxidative stress, BAX, and Caspase-3 mRNA expression with the reduced number of hippocampal neurons, dentate gyrus volume, and neurogenesis, highlighting neurodegenerative and cognitive deficiency implication of these comorbidity treatments. Considering these findings, assessment of hippocampal well-being in patients with these comorbidities/treatment combinations is invaluable and caution is advised particularly in alcohol use with cART prophylaxis in diabetes.

Elamipretide alleviates pyroptosis in traumatically injured spinal cord by inhibiting cPLA2-induced lysosomal membrane permeabilization

Spinal cord injury (SCI) is a devastating injury that may result in permanent motor impairment. The active ingredients of medications are unable to reach the affected area due to the blood‒brain barrier. Elamipretide (SS-31) is a new and innovative aromatic cationic peptide. Because of its alternating aromatic and cationic groups, it freely crosses the blood‒brain barrier. It is also believed to decrease inflammation and protect against a variety of neurological illnesses. This study explored the therapeutic value of SS-31 in functional recovery after SCI and its possible underlying mechanism. A spinal cord contusion injury model as well as the Basso Mouse Scale, footprint assessment, and inclined plane test were employed to assess how well individuals could function following SCI. The area of glial scarring, the number of dendrites, and the number of synapses after SCI were confirmed by HE, Masson, MAP2, and Syn staining. Western blotting, immunofluorescence, and enzyme-linked immunosorbent assays were employed to examine the expression levels of pyroptosis-, autophagy-, lysosomal membrane permeabilization (LMP)- and MAPK signalling-related proteins. The outcomes showed that SS-31 inhibited pyroptosis, enhanced autophagy and attenuated LMP in SCI. Mechanistically, we applied AAV vectors to upregulate Pla2g4A in vivo and found that SS-31 enhanced autophagy and attenuated pyroptosis and LMP by inhibiting phosphorylation of cPLA2. Ultimately, we applied asiatic acid (a p38-MAPK agonist) to test whether SS-31 regulated cPLA2 partially through the MAPK-P38 signalling pathway. Our group is the first to suggest that SS-31 promotes functional recovery partially by inhibiting cPLA2-mediated autophagy impairment and preventing LMP and pyroptosis after SCI, which may have potential clinical application value.