ABSTRACT
OBJECTIVE CYP2 family including CYP2C and CYP2J is the predominant arachidonic acid (AA) epoxygenase, and the epoxidation of AA produces four regioisomeric cis-epoxyeicosatrienoic acids (5,6-, 8,9-, 11,12-, and 14,15-EET). Human CYP2J2 is one of the main CYP isoforms expressed in brain, but CYP2C8 was present at a low level. The aim of this study is to investigate the roles of brain CYP2J in Parkinson disease. METHODS Rats received the right-unilaterally injection with concentrated LV-CYP2J3 or LV-EGFP in the substantia nigra (SN) at 3 d before LPS or 6-OHDA treatment. The animals were tested for rotational behavior with the dopaminergic agonist apomorphine dissolved in sterile saline at 14 and 21 d after LPS injection. The influence of CYP2J-dependent derivative, 14,15-EET, on the genes related with oxidative stress was assayed in SH-SY5Y cells. RESULTS CYP2J overexpression or 14,15-EET treatment significantly increased the levels of SOD1, CAT, GPX1, NRF2 and KEAP1 in neurons. TLR4- MyD88 signaling pathway was involved the down- regulation of CYP2J by LPS. The binding of p-CREB with the promoter of CYP2J was inhibited by the LPS treatment. The loss of dopami?nergic neurons in the right SN induced by LPS or 6- OHDA was significantly decreased by CYP2J3 transfection at 21 d after LPS injection. Compared with LPS or 6-OHDA group, the number of the rotation of rats was decreased by 42.6% and 60.7% by CYP2J3 transfection at 14 d after LPS or 6-OHDA injection;meanwhile, the rotation number was decreased by 12.7% and 21.3% at 21 d. The accumulation of alpha synuclein induced by LPS was significantly decreased by CYP2J3 transfection. The mRNA levels of SOD1, CAT, GPX1, NRF2 and KEAP1 in SN were decreased by LPS, which was attenuated by the injection of LV-CYP2J3. CONCLUSION Brain CYP2J can play a protective role in the damage of the inflammation and oxidative stress to the dopaminergic neurons. Brain CYP2J- dependent derivatives from AA may have therapeutic effects in Parkinson disease via the up- regulation of the antioxidant system in neurons.
ABSTRACT
OBJECTIVE CYP2D is one of the most abundant subfamily of CYPs in the brain, especially in the cerebellum. Brain CYP2D is responsible for the metabolism of endogenous neurotransmitters such as tyramine and serotonin. Our previous studies have shown brain CYP2D can be regulated by exogenous and endogenous substances with tissue- specificity. The purpose of this study is to examine the effects of cerebral CYP2D on the mice behavior and the regulatory mechanism of brain CYP2D by growth hormone. METHODS Mice received the stereotaxic injection with CYP2D inhibitor quinine in deep cerebellar nuclei of cerebellum. The animals were tested with rotarod apparatus, balance beam, water maze, elevated plus maze and open field. The changes in CYP2D22, PPARαand PPARγ in brain regions and liver were assayed in male growth hormone receptor knockout mice, SH-SY5Y cells and HepG2 cells. RESULTS The inhibition of cerebellum CYP2D significantly affected the spatial learning and exploring ability of mice. Compared with WT mice, CYP2D expression was lower in brain regions from GHR(-/- ) male mice; however, hepatic CYP2D level was similar. Pulsatile GH decreased PPARα mRNA level, and increased mRNA levels of CYP2D6 and PPARα in SH- SY5Y cells. In HepG2 cells, pulsatile GH resulted in decreases in PPARα and PPARγ mRNA levels, but not CYP2D6. PPARα inhibitor induced CYP2D6 mRNA and protein by 1.32-fold and 1.43-fold in SH-SY5Y cells. PPARγ inhibitor decreased CYP2D6 mRNA and protein by 74.76% and 40.93%. PPARα agonist decreased the level of CYP2D22 mRNA in liver and cerebellum, while PPARγ agonist rosiglitazone resulted in diametrically increases. The luciferase assay showed that PPARγ actived the CYP2D6 gene promoter while PPARα inhibited its function. Pulsatile GH declined the binding of PPARα with CYP2D6 promoter by 40%, promoted the binding of PPARγ with CYP2D6 promoter by approximate 60%. The levels of brain and liver PPARα expression in male GHR(-/- ) mice is obviously higher than those in WT mice. The level of PPARγ in male GHR(-/- ) mice was decreased in the frontal cortex and hippocampus, while remained stable in the cerebellum and striatum; meanwhile, PPARγ was increased in the liver. CONCLUSION Brain CYP2D may be involved in learning and memory functions of central system. Masculine GH secretion altered the PPARs expression and the binding of PPARs to CYP2D promoter, leading to the elevated brain CYP2D in a tissue- specific manner. Growth hormone may specifically alter the metabolic and synthetic of important endogenous substances in the central nervous system (such as serotonin) through the specific regulation of brain CYP2D expression.
ABSTRACT
OBJECTIVE Neuroinflammation plays a critical role in neurodegenerative disorders, although the inflammation may not the initiating factor. Parkinson disease (PD) is characterized patho?logically by the accumulation of alpha synuclein (α-syn) and the loss of the dopamine (DA) neurons in the substantia nigra (SN), which has been reported to be induced by the stereotaxic injection of lipopolysaccharide (LPS) to the SN region in rodents. This study is to investigate the therapeutic benefit of the inhibition of miR-873 in PD. METHODS Rats received the right-unilaterally injection with concentrated LV-sponge or LV-EGFP 3 d before LPS treatment, 7 or 14 d after LPS treatment. The animals were tested for rotational behavior with the dopaminergic agonist apomorphine dissolved in sterile saline at 21 d after LPS injection. The regulation of miR-873 on the genes related with cholesterol transport and inflammation was assayed in SH-SY5Y cells and U251 cells. RESULTS TLR4-MyD88 signaling pathway was involved the regulation of miR-873 by LPS. The luciferase assay showed that HMGCR, ABCA1 and A20 were down- stream genes of miR- 873. The transfection of miR- 873 decreased the cholesterol levels in cell membrane, but increased in lysosome in SH-SY5Y cells. Compared with the control SH-SY5Y cells, cholesterol levels were higher in lysosome with α-synuclein overexpression or LPS treatment. The transfection of miR-873 increased the α-syn levels in lysosome in cells with α-synuclein overexpression. The loss of dopaminergic neuorns induced by LPS was significantly respectively decreased by 22.8%, 35.6% and 57% after the inhibition of miR-873 at 3 d before LPS treatment, 7 or 14 d after LPS treatment. Compared with LPS-treated group, the number of the rotation of rats was decreased by 60.4%, 33.5% and 13.2% after the inhibition of miR-873 at 3 d before LPS treatment, 7 or 14 d after LPS treatment. The inhibition of miR-873 significantly decreased accumulation of α-syn. The mRNA levels of HMGCR, ABCA1 and A20 in SN were decreased by LPS treatment, which was attenuated by the injection of LV- sponge. CONCLUSION The selective regulation of miR- 873 can protect the dopaminergic neurons from the LPS-induced damage. The inhibition of miR-873 can attenuate the relocation of cholesterol in lysosome and the accumulation of α-syn in neurons induced by LPS via the regulation of HMGCR, ABCA1 and A20.