Functional Selectivity of Coumarin Derivates Acting via GPR55 in Neuroinflammation

Anti-neuroinflammatory treatment has gained importance in the search for pharmacological treatments of different neurological and psychiatric diseases, such as depression, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Clinical studies demonstrate a reduction of the mentioned diseases’ symptoms after the administration of anti-inflammatory drugs. Novel coumarin derivates have been shown to elicit anti-neuroinflammatory effects via G-protein coupled receptor GPR55, with possibly reduced side-effects compared to the known anti-inflammatory drugs. In this study, we, therefore, evaluated the anti-inflammatory capacities of the two novel coumarin-based compounds, KIT C and KIT H, in human neuroblastoma cells and primary murine microglia. Both compounds reduced PGE2-concentrations likely via the inhibition of COX-2 synthesis in SK-N-SH cells but only KIT C decreased PGE2-levels in primary microglia. The examination of other pro- and anti-inflammatory parameters showed varying effects of both compounds. Therefore, the differences in the effects of KIT C and KIT H might be explained by functional selectivity as well as tissue- or cell-dependent expression and signal pathways coupled to GPR55. Understanding the role of chemical residues in functional selectivity and specific cell- and tissue-targeting might open new therapeutic options in pharmacological drug development and might improve the treatment of the mentioned diseases by intervening in an early step of their pathogenesis.

Helicobacter Pylori Urease: Potential Contributions to Alzheimer’s Disease

Alzheimer’s disease (AD) causes dementia and memory loss in the elderly. Deposits of beta-amyloid peptide and hyperphosphorylated tau protein are present in AD’s brain. A filtrate of Helicobacter pylori’s culture was previously found to induce hyperphosphorylation of tau in vivo, suggesting that bacterial exotoxins could permeate the blood brain barrier and directly induce tau’s phosphorylation. H. pylori, which infects ~60% of the world population and causes gastritis and gastric cancer, produces a pro-inflammatory urease (HPU). Here the neurotoxic potential of HPU was investigated in cultured cells and in rats. SH-SY5Y neuroblastoma cells exposed HPU (50-300 nM) produced reactive oxygen species (ROS) and had an increased [Ca2+]i. HPU-treated BV-2 microglial cells produced ROS, cytokines IL-1β and TNF-α, expressed Iba1 and showed reduced viability, consistent with a neurotoxic effect of HPU. Rats received daily i.p. HPU (5 µg) for 7 days. Hyperphosphorylation of tau at Thr205, Ser199 and Ser396 sites was seen in hippocampal homogenates of treated rats, with no alterations in total tau or GSK-3b levels. HPU was not detected in the brain homogenates. Behavioral tests were performed to assess cognitive impairments. Our findings support previous data suggesting an association between infection by H. pylori and tauopathies such as AD, possibly mediated by its urease.

RNA binding protein HuD promotes autophagy and tumor stress survival by suppressing mTORC1 activity and augmenting ARL6IP1 levels

Background Neuronal-origin HuD (ELAVL4) is an RNA binding protein overexpressed in neuroblastoma (NB) and certain other cancers. The RNA targets of this RNA binding protein in neuroblastoma cells and their role in promoting cancer survival have been unexplored. In the study of modulators of mTORC1 activity under the conditions of optimal cell growth and starvation, the role of HuD and its two substrates were studied. Methods RNA immunoprecipitation/sequencing (RIP-SEQ) coupled with quantitative real-time PCR were used to identify substrates of HuD in NB cells. Validation of the two RNA targets of HuD was via reverse capture of HuD by synthetic RNA oligoes from cell lysates and binding of RNA to recombinant forms of HuD in the cell and outside of the cell. Further analysis was via RNA transcriptome analysis of HuD silencing in the test cells. Results In response to stress, HuD was found to dampen mTORC1 activity and allow the cell to upregulate its autophagy levels by suppressing mTORC1 activity. Among mRNA substrates regulated cell-wide by HuD, GRB-10 and ARL6IP1 were found to carry out critical functions for survival of the cells under stress. GRB-10 was involved in blocking mTORC1 activity by disrupting Raptor-mTOR kinase interaction. Reduced mTORC1 activity allowed lifting of autophagy levels in the cells required for increased survival. In addition, ARL6IP1, an apoptotic regulator in the ER membrane, was found to promote cell survival by negative regulation of apoptosis. As a therapeutic target, knockdown of HuD in two xenograft models of NB led to a block in tumor growth, confirming its importance for viability of the tumor cells. Cell-wide RNA messages of these two HuD substrates and HuD and mTORC1 marker of activity significantly correlated in NB patient populations and in mouse xenografts. Conclusions HuD is seen as a novel means of promoting stress survival in this cancer type by downregulating mTORC1 activity and negatively regulating apoptosis.

The microRNA-455 Null Mouse Has Memory Deficit and Increased Anxiety, Targeting Key Genes Involved in Alzheimer’s Disease

The complete molecular mechanisms underlying the pathophysiology of Alzheimer’s disease (AD) remain to be elucidated. Recently, microRNA-455-3p has been identified as a circulating biomarker of early AD, with increased expression in post-mortem brain tissue of AD patients. MicroRNA-455-3p also directly targets and down-regulates APP, with the overexpression of miR-455-3p suppressing its toxic effects. Here, we show that miR-455-3p expression decreases with age in the brains of wild-type mice. We generated a miR-455 null mouse utilising CRISPR-Cas9 to explore its function further. Loss of miR-455 resulted in increased weight gain, potentially indicative of metabolic disturbances. Furthermore, performance on the novel object recognition task diminished significantly in miR-455 null mice (p = 0.004), indicating deficits in recognition memory. A slight increase in anxiety was also captured on the open field test. BACE1 and TAU were identified as new direct targets for miR-455-3p, with overexpression of miR-455-3p leading to a reduction in the expression of APP, BACE1 and TAU in neuroblastoma cells. In the hippocampus of miR-455 null mice at 14 months of age, the levels of protein for APP, BACE1 and TAU were all increased. Such findings reinforce the involvement of miR-455 in AD progression and demonstrate its action on cognitive performance.

Enantioselective Synthesis and Pharmacological Evaluation of Aza-CGP37157–Lipoic Acid Hybrids for the Treatment of Alzheimer’s Disease

Hybrids based on an aza-analogue of CGP37157, a mitochondrial Na+/Ca2+ exchanger antagonist, and lipoic acid were obtained in order to combine in a single molecule the antioxidant and NRF2 induction properties of lipoic acid and the neuroprotective activity of CGP37157. The four possible enantiomers of the hybrid structure were synthesized by using as the key step a fully diastereoselective reduction induced by Ellman’s chiral auxiliary. After computational druggability studies that predicted good ADME profiles and blood–brain permeation for all compounds, the DPPH assay showed moderate oxidant scavenger capacity. Following a cytotoxicity evaluation that proved the compounds to be non-neurotoxic at the concentrations tested, they were assayed for NRF2 induction capacity and for anti-inflammatory properties and measured by their ability to inhibit nitrite production in the lipopolysaccharide-stimulated BV2 microglial cell model. Moreover, the compounds were studied for their neuroprotective effect in a model of oxidative stress achieved by treatment of SH-SY5Y neuroblastoma cells with the rotenone–oligomycin combination and also in a model of hyperphosphorylation induced by treatment with okadaic acid. The stereocenter configuration showed a critical influence in NRF2 induction properties, and also in the neuroprotection against oxidative stress experiment, leading to the identification of the compound with S and R configuration as an interesting hit with a good neuroprotective profile against oxidative stress and hyperphosphorylation, together with a relevant anti-neuroinflammatory activity. This interesting multitarget profile will be further characterized in future work.

Investigation of Chemopreventive and Antiproliferative Potential of Dicliptera roxburghiana

Context: Carcinogenesis causes much human misery. It is a process involving multistage alterations. Medicinal plants are candidates for beneficial anticancer agents. Objectives: Investigation of anticancer proficiencies of the plant Dicliptera roxburghiana. Material and methods: Crude extract and derived fractions were inspected for their inhibitory potential against nuclear factor KB (NFκB), nitric oxide synthase inhibition, aromatase inhibition and induction of quinone reductase 1 (QR 1). Antiproliferative activity was determined by using various cancer cell lines for example hormone responsive breast cancer cell line MCF-7, estrogen receptor negative breast cancer cell line MDA-MB-231, murine hepatoma cells Hepa 1c1c7, human neuroblastoma cells SK-N-SH and neuroblastoma cells MYCN-2. Results: Ethyl acetate and n-butanol fractions of D. roxburghiana were strongly active against NFκB with IC50 of 16.6 ± 1.3 and 8.4 ± 0.7 µg/ml respectively with 100% survival. Chloroform fraction of the plant exhibited an induction ratio of 2.4 ± 0.09 with CD value of 17.7 µg/ml. Regarding the nitrite assay, the n-hexane fraction exhibited significant inhibition of NO activity with IC50 of 17.8 ± 1.25 µg/ml. The n-butanol fraction exhibited strong antiproliferative activity against IcIc-7 cell lines with IC50 values of 13.6 ± 1.91 µg/ml; against MYCN-2 a cytotoxic effect developed with dose dependence, with IC50 of 12.6 ± 1.24 µg/ml. In antiproliferative activity against SK-N-SH cell lines, chloroform, ethyl acetate and n-butanol fractions were efficiently active with IC50 values of 11.2 ± 0.84, 14.6 ± 1.71 and 16.3 ± 1.57 respectively. Discussion and Conclusion: It was demonstrated that various fractions of D. roxburghiana displayed appreciable anticancer characteristics and could be a potent source for the development of anticancer leads.

Itchy E3 ubiquitin-protein ligase promotes neuroblastoma progression in vitro and in vivo

[Objective] Neuroblastoma is the most common pediatric neuroendocrine tumor. Patients with high-risk neuroblastoma have poor clinical outcomes. Understanding the mechanisms underlying neuroblastoma progression could help identify potential therapeutic targets. This study aimed to explore the roles of itchy E3 ubiquitin-protein ligase (ITCH) in neuroblastoma progression using neuroblastoma cell lines and xenograft models of neuroblastoma. [Methods] ITCH-silencing or overexpressing neuroblastoma cells were established using two different human neuroblastoma cell lines, SK-N-AS and SH-SY5Y. In vitro and in vivo experiments were carried out to determine the effects of ITCH on neuroblastoma cell behaviors. The dual-luciferase reporter assay and co-transfection experiments were applied to determine the interaction of ITCH and miR-145-5p during neuroblastoma progression. [Results] In both cell lines, ITCH overexpression significantly promotes the proliferation, migration, and invasion capacities of neuroblastoma cells, while ITCH silencing with ShITCH suppressed neuroblastoma cell proliferation and induced apoptosis. Moreover, overexpression of ITCH decreased 51% and 54% the protein expressions of large tumor suppressor kinase 1 (LATS1), and inhibited 59% and 66% the phosphorylation of Yes-associated protein (YAP), concomitant with 2.02-fold and 2.56-fold increased expressions of cell proliferation marker Ki67 and 2.51-fold and 2.26-fold elevated levels of anti-apoptosis marker Bcl2 in SK-N-AS and SH-SY5Y cells, respectively. The dual-luciferase reporter assay demonstrated that ITCH interacted with miR-145-5p. Further in vitro and xenograft experiments showed that ITCH negatively affected the tumor-suppressive effect of miR-145-5p. [Conclusion] ITCH promotes neuroblastoma cell proliferation and metastasis by inhibiting LATS1 and promoting YAP nuclear translocation.