Ago2 and Dicer1 are involved in METH-induced locomotor sensitization in mice via biogenesis of miRNA.

microRNA (miRNA) play important roles in drug addiction and act as a post-transcriptional regulator of gene expression. We previously reported extensive downregulation of miRNAs in the nucleus accumbens (NAc) of methamphetamine (METH)-sensitized mice. However, the regulatory mechanism of this METH-induced downregulation of miRNAs has yet to be elucidated. Thus, we examined METH-induced changes in the expression of miRNAs and their precursors, as well as the expression levels of mRNA and the proteins involved in miRNA biogenesis such as Dicer1 and Ago2, in the nucleus accumbens of METH-induced locomotor sensitized mice. miRNAs and Ago2 were significantly downregulated, while the expression of miRNA precursors remained unchanged or upregulated, which suggests that the downregulation of miRNAs was likely due to a reduction in Ago2-mediated splicing but unlikely to be regulated at the transcription level. Interestingly, the expression level of Dicer1, which is a potential target of METH-induced decreased miRNAs, such as miR-124, miR-212 and miR-29b, was significantly increased. In conclusion, this study indicates that miRNA biogenesis (such as Ago2 and Dicer1) and their miRNA products may have a role in the development of METH addiction.

Inhibitory effects of methamphetamine on mast cell activation and cytokine/chemokine production stimulated by lipopolysaccharide in C57BL/6J mice.

Previous studies have demonstrated that methamphetamine (MA) influences host immunity; however, the effect of MA on lipopolysaccharide (LPS)-induced immune responses remains unknown. Mast cells (MCs) are considered to serve an important role in the innate and acquired immune response, but it remains unknown whether MA modulates MC activation and LPS-stimulated cytokine production. The present study aimed to investigate the effect of MA on LPS-induced MC activation and the production of MC-derived cytokines in mice. Markers for MC activation, including cluster of differentiation 117 and the type I high affinity immunoglobulin E receptor, were assessed in mouse intestines. Levels of MC-derived cytokines in the lungs and thymus were also examined. The results demonstrated that cytokines were produced in the bone marrow-derived mast cells (BMMCs) of mice. The present study demonstrated that MA suppressed the LPS-mediated MC activation in mouse intestines. MA also altered the release of MC cytokines in the lung and thymus following LPS stimulation. In addition, LPS-stimulated cytokines were decreased in the BMMCs of mice following treatment with MA. The present study demonstrated that MA may regulate LPS-stimulated MC activation and cytokine production.

The effects of D3R on TLR4 signaling involved in the regulation of METH-mediated mast cells activation.

Accumulating studies have revealed that the dopamine D3 receptor (D3R) plays an important role in methamphetamine (METH) addiction. However, the action of D3R on METH-mediated immune response and the underlying mechanism remain unclear. Mast cells (MCs) are currently identified as effector cells in many processes of immune responses, and MC activation is induced by various stimuli such as lipopolysaccharide (LPS). Moreover, CD117 and FcεRI are known as MC markers due to their specific expression in MCs. To investigate the effects of D3R on METH-mediated alteration of LPS-induced MCs activation and the underlying mechanism, in this study, we examined the expression of CD117 and FcεRI in the intestines of wild-type (D3R(+/+)) and D3R-deficient (D3R(-/-)) mice. We also measured the production of MC-derived cytokines, including TNF-α, IL-6, IL-4, IL-13 and CCL-5, in the bone marrow-derived mast cells (BMMCs) of WT and D3R(-/-) mice. Furthermore, we explored the effects of D3R on METH-mediated TLR4 and downstream MAPK and NF-κB signaling induced by LPS in mouse BMMCs. We found that METH suppressed MC activation induced by LPS in the intestines of D3R(+/)mice. In contrast, LPS-induced MC activation was less affected by METH in D3R(-/-) mice. Furthermore, METH altered LPS-induced cytokine production in BMMCs of D3R(+/+) mice but not D3R(-/-) mice. D3R was also involved in METH-mediated modulation of LPS-induced expression of TLR4 and downstream MAPK and NF-κB signaling molecules in mouse BMMCs. Taken together, our findings demonstrate that the effect of D3R on TLR4 signaling may be implicated in the regulation of METH-mediated MCs activation induced by LPS.

The dopamine D3 receptor regulates the effects of methamphetamine on LPS-induced cytokine production in murine mast cells.

Previous studies have demonstrated that methamphetamine (METH) alter inflammatory and anti-inflammatory cytokine production in the periphery. However, the effect of METH on lipopolysaccharide (LPS)-induced immune responses and its underlying mechanism of action remains unclear. The dopamine D3 receptor (D3R) plays an important role in METH addiction, indicating that the D3R may regulate METH-mediated immune responses. In this study, we examined the effect of METH on mast cell released cytokines in the lungs and thymi of mice stimulated by LPS, and on LPS-induced murine bone marrow-derived mast cells (BMMCs). Moreover, we used D3R-deficient mice to investigate the effect of this receptor on LPS-stimulated mast cell released cytokine production after METH treatment in the lungs and thymi. The effects of a D3R agonist and antagonist on LPS-induced cytokine production after METH treatment in murine BMMCs were also evaluated. METH suppressed LPS-induced cytokine production in the lungs and thymi of wild-type (WT) mice and BMMCs. However, METH did not alter LPS-induced cytokine production in the lungs and thymi of D3R-deficient mice. When BMMCs were treated with the D3R receptor antagonist, NGB2904 hydrochloride (NGB-2904), METH did not alter LPS-induced cytokine production. However, treatment with the D3R agonist, 7-hydroxy-(di-n-propylamino) tetralin (7-OH-DPAT), significantly enhanced the effects of METH on LPS-induced cytokine production. Our results suggest that METH regulates mast cell released cytokines production in an LPS-induced mouse model via the D3R.

Roles of levo-tetrahydropalmatine in modulating methamphetamine reward behavior.

Levo-tetrahydropalmatine (l-THP), as an alkaloid purified from the traditional Chinese herbal medicine Corydalis and Stephania, has been widely used to produce many traditional Chinese herbal preparations. The effect of l-THP on methamphetamine-induced reward learning still remains unclear although it has been proved to be effective on treating allodynia and drug addiction. This experiment has been designed to examine the effect of l-THP on the acquisition, expression, extinction, and reinstatement of methamphetamine-induced conditioned place preference (CPP) in mice. The results show that methamphetamine (METH) could induce CPP in mice at doses of 0.5mg/kg, 1.0mg/kg and 2.0mg/kg respectively, but l-THP alone could not do so. Meanwhile, l-THP could not induce conditioned place aversion at doses of 1.25mg/kg to 20.0mg/kg in mice, but it could attenuate the acquisition and expression of METH-induced CPP and facilitate the extinction of METH-induced CPP in mice. Besides, l-THP could inhibit the reinstatement of METH-induced CPP at the dose of 10.0mg/kg whether it was given in the extinction training phase or 30min before the reinstatement. These results suggest that l-THP can globally suppress the rewarding properties of METH on all phases of the CPP task and it may have potential effects on the treatment of METH abuse.

Tetrahydropalmatine protects against methamphetamine-induced spatial learning and memory impairment in mice.

OBJECTIVE: The purpose of this study was to investigate the effect of methamphetamine (MA) on spatial learning and memory and the role of tetrahydropalmatine (THP) in MA-induced changes in these phenomena in mice. METHODS: Male C57BL/6 mice were randomly divided into eight groups, according to different doses of MA, different doses of THP, treatment with both MA and THP, and saline controls. Spatial learning and memory were assessed using the Morris water maze. Western blot was used to detect the expression of extracellular signal-regulated protein kinase (ERK) in the mouse prefrontal cortex (PFC) and hippocampus. RESULTS: Repeated MA treatment significantly increased the escape latency in the learning phase and decreased the number of platform site crossings in the memory-test phase. ERK1/2 expression was decreased in the PFC but not in the hippocampus of the MA-treated mice. Repeated THP treatment alone did not affect the escape latency, the number of platform site crossings or the total ERK1/2 expression in the brain. Statistically significantly shorter escape latencies and more platform site crossings occurred in MA+THP-treated mice than in MA-treated mice. CONCLUSION: Repeated MA administration impairs spatial learning and memory in mice, and its co-administration with THP prevents this impairment, which is probably attributable to changed ERK1/2 expression in the PFC. This study contributes to uncovering the mechanism underlying MA abuse, and to exploring potential therapies.

Vascular endothelial growth factor up-regulates the expression of intracellular adhesion molecule-1 in retinal endothelial cells via reactive oxygen species, but not nitric oxide.

BACKGROUND: The vascular endothelial growth factor (VEGF) is involved in the initiation of retinal vascular leakage and nonperfusion in diabetes. The intracellular adhesion molecule-1 (ICAM-1) is the key mediator of the effect of VEGFs on retinal leukostasis. Although the VEGF is expressed in an early-stage diabetic retina, whether it directly up-regulates ICAM-1 in retinal endothelial cells (ECs) is unknown. In this study, we provided a new mechanism to explain that VEGF does up-regulate the expression of ICAM-1 in retinal ECs. METHODS: Bovine retinal ECs (BRECs) were isolated and cultured. Immunohistochemical staining was performed to identify BRECs. The cultured cells were divided into corresponding groups. Then, VEGF (100 ng/ml) and other inhibitors were used to treat the cells. Cell lysate and the cultured supernatant were collected, and then, the protein level of ICAM-1 and phosphorylation of the endothelial nitric oxide synthase (eNOS) were detected using Western blotting. Griess reaction was used to detect nitric oxide (NO). RESULTS: Western blotting showed that the VEGF up-regulated the expression of ICAM-1 protein and increased phosphorylation of the eNOS in retinal ECs. Neither the block of NO nor protein kinase C (PKC) altered the expression of ICAM-1 or the phosphorylation of eNOS. The result of the Western blotting also showed that inhibition of phosphatidylinositol 3-kinase (PI3K) or reactive oxygen species (ROS) significantly reduced the expression of ICAM-1. Inhibition of PI3K also reduced phosphorylation of eNOS. Griess reaction showed that VEGF significantly increased during NO production. When eNOS was blocked by L-NAME or PI3K was blocked by LY294002, the basal level of NO production and the increment of NO caused by VEGF could be significantly decreased. CONCLUSION: ROS-NO coupling in the retinal endothelium may be a new mechanism that could help to explain why VEGF induces ICAM-1 expression and the resulting leukostasis in diabetic retinopathy.

[Genetic polymorphisms of X-STR loci in Chinese Yugur ethnic group and its application].

To study the genetic polymorphism of nine short tandem repeats (STRs) loci (DXS7130, DXS7132, DXS6804, DXS7423, DXS7424, DXS6789, DXS6799, DXS8378, and HPRTB) on X chromosome in Chinese Yugur ethnic group. The allele and genotype frequency of nine X-STR loci among 120 unrelated individuals (55 female, 65 male) from Yugur ethnic group were analyzed using PCR and followed by polyacrylamide gel electrophoresis and silver staining. The numbers of alleles in the nine X-STR loci were 8, 6, 6, 5, 6, 7, 6, 4, and 6, respectively; the numbers of genotypes in the nine loci were 16, 14, 13, 6, 13, 20, 11, 6, and 12, respectively. The genotype frequencies in females were in accordance with Hardy-Weinberg equilibrium (P>0.05). The nine X-STR loci were relatively abundant in polymorphic information for individual identification, paternity testing and population genetics. A total of 15 haplotypes were detected in DXS7130 and DXS8378 loci, and 55 haplotypes were detected in DXS6789, DXS6799, DXS7424, and DXS6804 loci. The haplotype diversity reached 0.8212 and 0.9947, respectively. Phylogeny tree and cluster analysis based on X-STR allele frequencies in genesis showed that Yugur ethnic group share a close relationship with Mongolian ethnic group and Chinese Han, Tibetan population and far from Hui and Uygur ethnic group, who dwell in the northwest of China.

[Sequencing and analyzing of expressed sequence tags (ESTs) of pig fat tissue].

In this paper,the ESTs of pig fat tissue were sequenced and analyzed using the large-scale DNA sequencing method, 7790 high quality ESTs were gained,from which 4354 genes were obtained using cluster analysis with the STACK-PACK software, including 3609 singlet genes and 745 multicopy genes. The 4354 candidate genes were compared with BLASTN to the nr library (e =1e-10), of which 2712 were known genes, containing 1 987 singlet genes and 725 multicopy genes,there are 2 109 unknown genes and new ESTs. Based on the results of BlastN and the index of GenBank Accenssion No., the known gene expression profile of pig fat were constructed. It showed that the genes participating in metabolism held the highest proportion in the 7 sorts, and in some aspects showed the hearty metabolism activity of fat tissue. 257 total reads of the Major Histocompatibility Complex (MHC) genes in the pig fat tissue were found,including 181 singlet genes and 44 multicopy genes. They account for 44.9% of the cell and organism defense, and 5.4% of all known genes,from this we can see that the MHC has a fairly high expression degree. Comparing all ESTs related with MHC (257reads) with known pig BAC we found the partial sequences (approximately 200 bp) of the ESTs distributing to every exon of. We can predict that the ESTs in MHC contain approximately 200 bp highly consistent regions and every exon possesses one of these regions. Although these MHC sequences in different BAC have different protein domains,they are highly consistent and related with immune functions. When the MHC genes transfer to the next generation,they can duplicate repeatly and inherit stably.

[Studies of STR polymorphisms in Pumi and Lisu minorities in China].

In this study, we investigated the polymorphisms of STR of Pumi and Lisu minorities with STR genescan marked by fluorescence. Eighty-five alleles of 9 STR in Pumi were detected with the frequency 0.0050-0.5250 and 194 genotypes were found with frequency of 0.0098-0.3235. Sixty three alleles with their frequency of 0.0050-0.4802 and 145 genotypes were found out with frequency of 0.0099-0.3664 in Lisu population. Hi-Square test indicated the distribution of genotypes agreed with Hardy-Weinberg equilibrium (P > 0.05). Statistical analysis showed the followings: H > 0.6 in each locus, the average PIC > 0.7, mean DP > 0.8, EPP > 0.5, indicating the STR markers used in the study were of great value in the researches on minority genetics.