CDK11(p58) promotes rat astrocyte inflammatory response via activating p38 and JNK pathways induced by lipopolysaccharide

CDK10, CDK11, FOXO1, and FOXO3 Gene Expression in Alzheimer's Disease Encephalic Samples

Alzheimer's disease (AD) is a progressive neuroinflammatory and neurodegenerative disorder that affects different regions of the brain. Its pathophysiology includes the accumulation of β-amyloid protein, formation of neurofibrillary tangles, and inflammatory processes. Genetic factors are involved in the onset of AD, but they are not fully elucidated. Identification of gene expression in encephalic tissues of patients with AD may help elucidate its development. Our objectives were to characterize and compare the gene expression of CDK10, CDK11, FOXO1, and FOXO3 in encephalic tissue samples from AD patients and elderly controls, from the auditory cortex and cerebellum. RT-qPCR was used on samples from 82 individuals (45 with AD and 37 controls). We observed a statistically significant increase in CDK10 (p = 0.029*) and CDK11 (p = 0.048*) gene expression in the AD group compared to the control, which was most evident in the cerebellum. Furthermore, the Spearman test demonstrated the presence of a positive correlation of gene expression both in the auditory cortex in the AD group (r = 0.046/p = 0.004) and control group (r = 0.454/p = 0.005); and in the cerebellum in the AD group (r = 0.654 /p < 0.001). There was no statistically significant difference and correlation in the gene expression of FOXO1 and FOXO3 in the AD group and the control. In conclusion, CDK10 and CDK11 have high expression in AD patients compared to control, and they present a positive correlation of gene expression in the analyzed groups and tissues, which suggests that they play an important role in the pathogenesis of AD.

Modulation of Astrocytic Glutamine Synthetase by Endocannabinoid 2-Arachidonoylglycerol in JNK-Independent Pathway

Background and Objective: The glutamine synthetase (GS), an astrocyte-specific enzyme, plays an important role in neuroprotection through the glutamate/glutamine shuttle and can be modulated by endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) through extracellular signal-regulated protein kinase ½ (ERK1/2) and p38 signaling pathways. However, the role of c-Jun N-terminal kinase (JNK) signaling pathway in the modulation of GS in astrocytes by 2-AG is not clear.

Materials and Methods: The expression of GS and JNK in astrocytes following the exposure to lipopolysaccharide (LPS) was examined with Western blotting and immunochemistry.

Results: The results revealed that short-term exposure to LPS activated GS and increased phosphorylation of JNK in astrocytes in a time-dependent manner. Treatment with 2-AG reversed the changes in GS but had no effect on the activation of JNK.

Conclusions: These findings suggest that the activation of JNK induced by LPS is not involved in the modulation of astrocytic GS by 2-AG.

Ethanol Extract of Elaeagnus glabra f. oxyphylla Branches Alleviates the Inflammatory Response Through Suppression of Cyclin D3/Cyclin-Dependent Kinase 11p58 Coupled to Lipopolysaccharide-Activated BV-2 Microglia

Neuroinflammation plays a pivotal role in the pathogenesis of neurodegenerative diseases and is characterized by microglial dysregulation. Here, we explored the beneficial effects of a leaf extract of Elaeagnus glabra f. oxyphylla (EGFO), a native medicinal plant to Korea, South China, Japan, and Taiwan, on neuroinflammation using lipopolysaccharide (LPS)-stimulated BV-2 microglia. Levels of the inflammatory mediators were determined by enzyme-linked immunosorbent assays and reverse transcription–polymerase chain reaction. The phospho levels of mitogen-activated protein kinases, which are key kinase molecules in the inflammatory signaling pathway in microglia, were analyzed by Western blotting. Treatment with EGFO significantly suppressed the LPS-mediated induction of nitric oxide and prostaglandin E2. Consistently, EGFO treatment in LPS-stimulated BV-2 cells markedly reduced the inflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels. The best concentration of EGFO that could reduce TNF-α and IL-6 was 100 μg/mL. EGFO relatively reduced the messenger RNA expression of TNF-α and IL-6 by 0.36 and 0.32-fold ratio, respectively, compared to LPS treatment. Moreover, EGFO markedly reduced the phospho levels of p38 and the c-jun N-terminal kinase. Furthermore, antibody microarray and immunoblotting data revealed that the pharmacological mechanisms driving the antineuroinflammatory action of EGFO involve prevention of the cyclin D3/cyclin-dependent kinase 11p58 (CDK11p58) interaction. In conclusion, our results demonstrate that EGFO alleviates the inflammatory response through the suppression of cyclin D3/CDK11p58 coupling in LPS-activated BV-2 microglia. We propose the potential of EGFO as a novel drug candidate for neurodegenerative diseases by targeting neuroinflammation.

Protease-activated receptor-2 regulates glial scar formation via JNK signaling

The study aimed to determine the effects of protease-activated receptor-2 (PAR-2) on glial scar formation after spinal cord injury (SCI) in Sprague-Dawley (SD) rats and the underlying mechanisms. Rivlin and Tator's acute extradural clip compression injury (CCI) model of severe SCI was established in this study. Animals were divided into four groups: 1) sham group (laminectomy only); 2) model group, treated with normal saline; 3) PAR-2 inhibitor group; 4) PAR-2 activator group. Enhanced GFAP and vimentin expression were the markers of glial scar formation. To determine whether JNK was involved in the effects of PAR-2 on GFAP and vimentin expression, we administered anisomycin (a JNK activator) in the presence of PAR-2 inhibitor and SP600125 (a JNK inhibitor) in the presence of PAR-2 activator. At 1, 7, 14 and 28 day after SCI, Basso, Beattie, and Bresnahan (BBB) locomotor score test was used to assess the locomotor functional recovery; immunofluorescence and western blot analysis were used to assess the expression level of GFAP, vimentin and p-JNK. Double immunofluorescence staining with GFAP and tubulin beta was used to assess the glial scar formation and the remaining neurons. Results suggested that PAR-2 is involved in glial scar formation and reduces neurons residues which can cause a further worsening in the functional outcomes after SCI via JNK signaling. Therefore, it may be effective to target PAR-2 in the treatment of SCI.

Upregulation of CBLL1 in rat brain cortex after lipopolysaccharide treated

CBLL1 (Casitas B-lineage lymphoma-transforming sequence-like protein 1) also known as Hakai, was originally identified as an E3 ubiquitin-ligase for the E-cadherin complex. Recent data have provided evidences for novel biological functional role of CBLL1 during tumor progression and other diseases. However, its distribution and function in the central nervous system (CNS) remains unclear. In this study, we found CBLL1 was significant up-regulation in cerebral cortex after LPS administration and immunofluorescent labeling indicated that CBLL1 was localized striking in the neurons. We also investigated co-staining of CBLL1 and active-caspase-3 and cyclin D1 in the cerebral cortex following LPS administration. Based on our data, we speculated that CBLL1 might play an important role in neuronal apoptosis following LPS administration and might provide a basis for the further study on its role in cell cycle re-entry in neuroinflammation in CNS.