LRRK2 G2019S promotes astrocytic inflammation induced by oligomeric α-synuclein through NF-κB pathway.

Parkinson's disease (PD) is characterized by the irreversible loss of dopaminergic neurons and the accumulation of α-synuclein in Lewy bodies. The oligomeric α-synuclein (O-αS) is the most toxic form of α-synuclein species, and it has been reported to be a robust inflammatory mediator. Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2) are also genetically linked to PD and neuroinflammation. However, how O-αS and LRRK2 interact in glial cells remains unclear. Here, we reported that LRRK2 G2019S mutation, which is one of the most frequent causes of familial PD, enhanced the effects of O-αS on astrocytes both in vivo and in vitro. Meanwhile, inhibition of LRRK2 kinase activity could relieve the inflammatory effects of both LRRK2 G2019S and O-αS. We also demonstrated that nuclear factor κB (NF-κB) pathway might be involved in the neuroinflammatory responses. These findings revealed that inhibition of LRRK2 kinase activity may be a viable strategy for suppressing neuroinflammation in PD.

Resolvin D1/N-formyl peptide receptor 2 ameliorates paclitaxel-induced neuropathic pain through the activation of IL-10/Nrf2/HO-1 pathway in mice.

Introduction: Paclitaxel is a chemotherapy drug that is commonly used to treat cancer, but it can cause paclitaxel-induced neuropathic pain (PINP) as a side effect. Resolvin D1 (RvD1) has been shown to be effective in promoting the resolution of inflammation and chronic pain. In this study, we evaluated the effects of RvD1 on PINP and its underlying mechanisms in mice. Methods: Behavioral analysis was used to assess the establishment of the PINP mouse model and to test the effects of RvD1 or other formulations on mouse pain behavior. Quantitative real-time polymerase chain reaction analysis was employed to detect the impact of RvD1 on 12/15 Lox, FPR2, and neuroinflammation in PTX-induced DRG neurons. Western blot analysis was used to examine the effects of RvD1 on FPR2, Nrf2, and HO-1 expression in DRG induced by PTX. TUNEL staining was used to detect the apoptosis of DRG neurons induced by BMDM conditioned medium. H2DCF-DA staining was used to detect the reactive oxygen species level of DRG neurons in the presence of PTX or RvD1+PTX treated BMDMs CM. Results: Expression of 12/15-Lox was decreased in the sciatic nerve and DRG of mice with PINP, suggesting a potential involvement of RvD1 in the resolution of PINP. Intraperitoneal injection of RvD1 promoted pain resolution of PINP in mice. Intrathecal injection of PTX-treated BMDMs induced mechanical pain hypersensitivity in naïve mice, while pretreatment of RvD1 in BMDMs prevented it. Macrophage infiltration increased in the DRGs of PINP mice, but it was not affected by RvD1 treatment. RvD1 increased IL-10 expression in the DRGs and macrophages, while IL-10 neutralizing antibody abolished the analgesic effect of RvD1 on PINP. The effects of RvD1 in promoting IL-10 production were also inhibited by N-formyl peptide receptor 2 (FPR2) antagonist. The primary cultured DRG neurons apoptosis increased after stimulation with condition medium of PTX-treated BMDMs, but decreased after pretreatment with RvD1 in BMDMs. Finally, Nrf2-HO1 signaling was additionally activated in DRG neurons after stimulation with condition medium of RvD1+PTX-treated BMDMs, but these effects were abolished by FPR2 blocker or IL-10 neutralizing antibody. Discussion: In conclusion, this study provides evidence that RvD1 may be a potential therapeutic strategy for the clinical treatment of PINP. RvD1/FPR2 upregulates IL-10 in macrophages under PINP condition, and then IL-10 activates the Nrf2- HO1 pathway in DRG neurons, relieve neuronal damage and PINP.

Gut Microbiota-Mediated Elevated Production of Secondary Bile Acids in Chronic Unpredictable Mild Stress.

A growing body of evidence suggests that gut microbiota could participate in the progression of depression via the microbiota-gut-brain axis. However, the detailed microbial metabolic profile changes in the progression of depression is still not fully elucidated. In this study, a liquid chromatography coupled to mass spectrometry-based untargeted serum high-throughput metabolomics method was first performed to screen for potential biomarkers in a depressive-like state in a chronic unpredictable mild stress (CUMS)-induced mouse model. Our results identified that the bile acid and energy metabolism pathways were significantly affected in CUMS progression. The detailed bile acid profiles were subsequently quantified in the serum, liver, and feces. The results showed that CUMS significantly promoted the deconjugation of conjugated bile acid and secondary bile acid biosynthesis. Furthermore, 16S rRNA gene sequencing revealed that the increased secondary bile acid levels in the feces positively correlated with Ruminococcaceae_UCG-010, Ruminococcus, and Clostridia_UCG-014 abundance. Taken together, our study suggested that changes in family Ruminococcaceae abundance following chronic stress increased biosynthesis of deoxycholic acid (DCA), a unconjugated secondary bile acid in the intestine. Aberrant activation of secondary bile acid biosynthesis pathway thereby increased the hydrophobicity of the bile acid pool, which might, in turn, promoted metabolic disturbances and disease progression in CUMS mice.

MiR-221-3p-mediated downregulation of MDM2 reverses the paclitaxel resistance of non-small cell lung cancer in vitro and in vivo.

MicroRNAs (miRNAs) are involved in the initiation and development of cancer and participate in drug resistance. Paclitaxel (PTX) is a first-line chemotherapy drug for advanced non-small cell lung cancer (NSCLC). The abnormal miRNA expression in NSCLC and its association with chemotherapy drug resistance remains largely unknown. The study aimed to investigate the aberrant expression of miR-221-3p in NSCLC and to elucidate its molecular mechanisms in relation to PTX resistance. PTX increased miR-221-3p expression and regulated MDM2/P53 expression in the PTX-sensitive NSCLC strain (A549). Meanwhile, miR-221-3p was rarely expressed and not interfered by PTX in PTX-resistant A549 cells (A549/Taxol). Dual-luciferase reporter assay confirmed that miR-221-3p specifically binds to MDM2 messenger RNA and inhibited MDM2 expression. The expression of MDM2 and P53 showed a negative correlation in NSCLC cell lines. MiR-221-3p down-regulation reduced the sensitivity of A549 cells to PTX, whereas its up-regulation partially reversed the A549/Taxol cells resistance to PTX and increased the chemosensitivity of A549/Taxol cells to PTX in xenograft models. Quantitative polymerase chain reaction analysis revealed that miR-221-3p expression increased, whereas the MDM2 level decreased in human NSCLC tumor tissues. Moreover, Western bolt analysis showed that P53 was lowly expressed in tumor tissues with MDM2 overexpression. Low expression of miR-221-3p in NSCLC tissues might indicate a poor T staging. In conclusion, miR-221-3p overexpression could regulate MDM2/p53 signaling pathway to reverse the PTX resistance of NSCLC and induce apoptosis in vitro and vivo.

Overexpression of hsa_circ_0002874 promotes resistance of non-small cell lung cancer to paclitaxel by modulating miR-1273f/MDM2/p53 pathway.

BACKGROUND: This study aimed to investigate the aberrant expression of hsa_circ_0002874 in non-small cell lung cancer (NSCLC) and elucidate associated molecular mechanisms that influence apoptosis and induce paclitaxel (PTX) resistance. METHODS: Inhibitors were used to downregulate circRNA or miRNA expression. pCDNA plasmid transfection and mimics were used to upregulate circRNA or miRNA expression. Dual-luciferase reporter assays were conducted to evaluate interactions between miR1273f and MDM2. Xenograft tumor models were used to assess the effect of hsa_circ_0002874 and miR1273f on tumor growth. NSCLC tissues and matched non-cancerous tissues were also collected for correlation analysis. RESULTS: hsa_circ_0002874 acts as a sponge for miR1273f which targets MDM2/P53. The stability of the hsa_circ_0002874/miR1273f/MDM2/P53 pathway was verified by upregulating and downregulating the expression of hsa_circ_0002874 and miR1273f. hsa_circ_0002874 downregulation or miR1273f upregulation reversed the resistance of the A549/Taxol cells in xenograft models. The expression of hsa_circ_0002874 was high, and the level of MDM2 was low in NSCLC tissues. P53 was only weakly expressed in NSCLC tissues with high expression of MDM2. CONCLUSIONS: hsa_circ_0002874 is strongly expressed in NSCLC tissues and maybe a potential marker for PTX resistance. hsa_circ_0002874 downregulation could regulate miR1273f/MDM2/P53 signaling pathway to reverse the PTX resistance of NSCLC and induce apoptosis in vitro and vivo.

Thioredoxin-Interacting Protein (TXNIP) Regulates Parkin/PINK1-mediated Mitophagy in Dopaminergic Neurons Under High-glucose Conditions: Implications for Molecular Links Between Parkinson's Disease and Diabetes.

Patients with diabetes mellitus have a higher risk of developing Parkinson's disease (PD). However, the molecular links between PD and diabetes remain unclear. In this study, we investigated the roles of thioredoxin-interacting protein (TXNIP) in Parkin/PINK1-mediated mitophagy in dopaminergic (DA) cells under high-glucose (HG) conditions. In streptozotocin-induced diabetic mice, TXNIP was upregulated and autophagy was inhibited in the midbrain, while the loss of DA neurons was accelerated by hyperglycemia. In cultured PC12 cells under HG, TXNIP expression was upregulated and the intracellular reactive oxygen species (ROS) levels increased, leading to cell death. Autophagic flux was further blocked and PINK1 expression was decreased under HG conditions. Parkin expression in the mitochondrial fraction and carbonyl cyanide 3-chlorophenylhydrazone (CCCP)-induced co-localization of COX IV (marker for mitochondria) and LAMP1 (marker for lysosomes) were also significantly decreased by HG. Overexpression of TXNIP was sufficient to decrease the expression of both PINK1 and Parkin in PC12 cells, while knockdown of the expression of TXNIP by siRNA decreased intracellular ROS and attenuated cellular injury under HG. Moreover, inhibition of TXNIP improved the CCCP-induced co-localization of COX IV and LAMP1 in PC12 cells under HG. Together, these results suggest that TXNIP regulates Parkin/PINK1-mediated mitophagy under HG conditions, and targeting TXNIP may be a promising therapeutic strategy for reducing the risk of PD under hyperglycemic conditions.

Paclitaxel promotes lung cancer cell apoptosis via MEG3-P53 pathway activation.

Paclitaxel (PTX) is a first-line chemotherapy drug for advanced non-small cell lung cancer (NSCLC). The long-chain non-coding RNA maternally expressed gene 3 (MEG3) is a recognized tumor suppressor. This study aimed to explore the effects of PTX on the expression of MEG3 and its anti-tumor mechanism in lung cancer cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to determine cell proliferation. Quantitative polymerase chain reaction was used to determine the levels of MEG3 expressions. Western blot and immunofluorescence were used to detect protein levels. Small interfering RNA or pCDNA-MEG3 transfection was used to downregulate or upregulate MEG3 expression. Dichlorof luorescein diacetate was used to detect intracellular reactive oxygen species. Flow cytometry was used to analyze apoptosis. PTX significantly inhibited the proliferation of NSCLC cells and increased the expressions of MEG3 and P53. The downregulation of MEG3 attenuated PTX-induced cytotoxicity, whereas upregulation of MEG3 induced cell death and increased P53 expression. The inhibition of P53 caused no effect on the upstream MEG3 expression. Our results suggest that the MEG3-P53 pathway is involved in the apoptosis of A549 cells induced by PTX.

Fenofibrate inhibits the growth of prostate cancer through regulating autophagy and endoplasmic reticulum stress.

Fenofibrate is a fibric acid derivative which exhibits a role of peroxisome proliferator-activated receptor-alpha agonist. It is widely utilized in therapy of hyperlipidemia and hypercholesterolemia. Its anticancer function is discovered in recent years. However, the role of fenofibrate in prostate cancer (PCa) is poorly understood. In this study, we investigated the function and mechanism of fenofibrate in PCa cells. Firstly, fenofibrate treated PCa cells showed more apoptosis compared with the control group. Further, we found that fenofibrate induced autophagy but finally blocked its complete flux in PCa cells through regulating AMPK-mTOR pathway. The intermediate metabolite from uncompleted autophagy induced endoplasmic reticulum stress (ER stress) via PERK and IRE1 signalings. In vivo mice model confirmed that fenofibrate inhibited the growth of PCa. This study suggests that fenofibrate is an effective inhibitor of PCa by regulating autophagy and ER stress.

Fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of LncRNA MEG3.

There is still no suitable drug for pancreatic cancer treatment, which is one of the most aggressive human tumors. Maternally expressed gene 3 (MEG3), a LncRNA, has been suggested as a tumor suppressor in a range of human tumors. Studies found fenofibrate exerted anti-tumor roles in various human cancer cell lines. However, its role in pancreatic cancer remains unknown. The present study aimed to explore the impacts of fenofibrate on pancreatic cancer cell lines, and to investigate MEG3 role in its anti-tumor mechanisms. We used MTT assay to determine cells proliferation, genome-wide LncRNA microarray analysis to identify differently expressed LncRNAs, siRNA or pCDNA-MEG3 transfection to interfere or upregulate MEG3 expression, western blot to detect protein levels, real-time PCR to determine MEG3 level. Fenofibrate significantly inhibited proliferation of pancreatic cancer cells, increased MEG3 expression and p53 levels. Moreover, knockdown of MEG3 attenuated cytotoxicity induced by fenofibrate. Furthermore, overexpression of MEG3 induced cells death and increased p53 expression. Our results indicated fenofibrate inhibited pancreatic cancer cells proliferation via activation of p53 mediated by upregulation of MEG3.