Brain cannabinoid receptor 2: expression, function and modulation.

Cannabis sativa (marijuana) is a fibrous flowering plant that produces an abundant variety of molecules, some with psychoactive effects. At least 4% of the world's adult population uses cannabis annually, making it one of the most frequently used illicit drugs in the world. The psychoactive effects of cannabis are mediated primarily through cannabinoid receptor (CBR) subtypes. The prevailing view is that CB1Rs are mainly expressed in the central neurons, whereas CB2Rs are predominantly expressed in peripheral immune cells. However, this traditional view has been challenged by emerging strong evidence that shows CB2Rs are moderately expressed and function in specific brain areas. New evidence has demonstrated that brain CB2Rs modulate animal drug-seeking behaviors, suggesting that these receptors may exist in brain regions that regulate drug addiction. Recently, we further confirmed that functional CB2Rs are expressed in mouse ventral tegmental area (VTA) dopamine (DA) neurons and that the activation of VTA CB2Rs reduces neuronal excitability and cocaine-seeking behavior. In addition, CB2R-mediated modulation of hippocampal CA3 neuronal excitability and network synchronization has been reported. Here, we briefly summarize recent lines of evidence showing how CB2Rs modulate function and pathophysiology in the CNS.

Identification and characterization of a novel splice-site mutation in the Wilson disease gene.

This study aimed to identify aberrant transcripts of the new splice-site mutation c.3244-2A>C in the Wilson disease (WD) gene (ATPase, Cu++ transporting, beta polypeptide, ATP7B) and discuss its genotype and clinical phenotype. DNA and RNA were extracted from peripheral blood lymphocytes, amplified by polymerase chain reaction (PCR) and nested reverse transcription PCR (RT-nested PCR) to characterize the aberrant transcripts. RT-nested PCR product sequencing comparison showed that c.3244-2A>C splice-site mutation caused aberrant transcripts and formatted a new splice acceptor. Patient carrying the splice-site mutation c.3244-2A>C presented early onset age, severe clinical manifestations, and poor prognosis. WD patients with the splice-site mutation show severe clinical manifestations, indicating that aberrant transcripts have important implications for WD phenotype.

Mutation analysis of 73 southern Chinese Wilson's disease patients: identification of 10 novel mutations and its clinical correlation.

This study was designed to investigate the molecular basis and the correlation between genotype and phenotype in the southern Chinese patients with Wilson's disease (WD). Genotypes of the ATP7B gene in 73 WD patients were examined by denaturing high-performance liquid chromatography (DHPLC) and DNA sequencing. A total of 38 different disease-causing mutations were identified, including 10 novel mutations: missense mutations (p.Gln707Arg, p.Cys1079Phe, p.Gly1149Glu, p.Ser855Tyr, p.Ala874Pro and p.Ser921Arg), nonsense mutation (p.Arg1228Stop), splice-site mutations (2121+3A>T and 3244-2A>G) and frameshift mutation (1875_1876insAATT). We found that a pair of siblings carried the same genotype but different clinical type, and two patients were found to have three mutations. In addition, we compared the clinical data for p.Arg778Leu homozygotes and compound heterozygotes. Our research has enriched the mutation spectrum of the ATP7B gene in the Chinese population and can serve as the basis for genetic counseling and clinical/prenatal diagnosis to prevent WD in China.

Super-high-dose methylprednisolone does not improve efficacy or induce glucocorticoid resistance in experimental allergic encephalomyelitis.

OBJECTIVE: To investigate whether a super-high dose (SHD) of methylprednisolone (MP) improves its efficacy or induces glucocorticoid (GC) resistance, and to explore the potential mechanisms of GC resistance in experimental allergic encephalomyelitis (EAE). METHODS: The therapeutic effects of SHD and low-dose MP were evaluated in EAE by analyzing clinical scores, pathological changes and cytokine production. Immunohistochemistry and RT-PCR were used to investigate the expression of GC receptor (GR) isoforms and splicing factor SRp30c. RESULTS: Both MP doses had similar therapeutic effects. The ratio of GRα to GRß was positively correlated with clinical score changes. However, there was no difference in the GRα/GRß ratio between SHD and low-dose MP groups. SRp30c mRNA was correlated with GRß expression. CONCLUSION: This study indicates that the GRα/GRß ratio is associated with GC sensitivity, and SRp30c may play an important role in promoting alternative splicing of GR pre-mRNA to generate GRß in EAE rats. Compared with low-dose MP, SHD MP does not improve efficacy or induce GC resistance.

[Relationship between angiotensin converting enzyme gene and ischemic stroke].

OBJECTIVE: To study relationship between angiotensin converting enzyme (ACE) gene and ischemic stroke (IS). METHODS: (1)Four hundred and fifty-four patients and 334 controls were recruited in our study, their I/D polymorphisms of ACE gene were detected by polymerase chain reaction (PCR) and denaturing high performance liquid chromatogram, and their risk factors of IS were recorded at the same time. (2)In addition, 29 stroke-prone spontaneously hypertensive rats (SHR-SP) and 40 Sprague-Dawley (SD) rats were enrolled, and hypoxia- apnoea animal models and simple apnoea animal models were used at the same time. Their plasma angiotensin II (Ang II) levels were determined. RESULTS: The frequencies of DD, ID and II genotype in IS patients were 22.5%, 43.4% and 34.1%, respectively, and 17.4%, 45.5% and 37.1%, respectively in controls. DD genotype was associated with large artery arteriosclerosis (LAA). Plasma Ang II level in SHR-SP group was (164.49+/-34.58) ng/L, and it was higher than that in control group [(150.92+/-24.92)ng/L] with no significant difference (P>0.05). Ang II levels in apnoea and hypoxia-apnoea group were (382.84+/-62.75) ng/L and (295.90+/-55.07) ng/L, respectively, and they were significantly higher than that in control group (all P<0.01). The relative risks of DD genotype and D alleles in IS patients with smoking, alcohol abuse, or with diabetes mellitus were higher than those in controls, but II genotype and I alleles were lower than those in controls. CONCLUSION: DD genotype is a risk factor for IS, Ang II takes part in the course of hypoxia-stress, and it is correlated with smoking, alcohol abuse and diabetes mellitus in the pathogenesis of IS.

[Relationship between methylenetrahydrofolate reductase gene and ischemic stroke].

OBJECTIVE: To study the relationship between methylenetrahydrofolate reductase (MTHFR) gene and ischemic stroke. METHODS: Four hundred and fifty four ischemic stroke patients were enrolled in the study. They were divided into large artery atherosclerosis (LAA), cardioembolism (CE), small artery occlusion (SAA), stroke of other determined etiology (SOE) and stroke of undetermined etiology (SUE) according to TOAST (Trail of ORG 10172 in Acute Stroke Treatment) criteria; and they were divided into mild, moderate and severe types ischemic stroke according to their scores of neurologic impairment. Three hundred and thirty four subjects, in whom hypertension, coronary heart disease, cerebral vascular disease, diabetes mellitus, cancer, renal failure etc. were excluded, served as controls in the study. Their C677T polymorphisms of MTHFR gene were determined with polymerase chain reaction (PCR) and denaturing high performance liquid chromatography (DHPLC), and their risk factors of ischemic stroke were recorded at the same time. RESULTS: The frequencies of CC, CT and TT genotype in ischemic stroke were 51.8%, 40.5% and 7.7%, respectively, and they were 56.9%, 38.3% and 4.8% respectively in controls. TT genotype and T allele were associated with LAA and CE, moderate type and severe type of ischemic stroke. The frequencies of TT genotype and T allele in ischemic stroke patients were significantly higher in those with smoking, alcohol abuse or diabetes mellitus than those in controls (all P<0.10), but CC genotype and C allele were significantly lower in them than those in controls (all P<0.05). On the other hand, all of genotypes and alleles in ischemic stroke patients with no history of smoking, alcohol abuse or diabetes mellitus were not significantly different from those in controls. CONCLUSION: TT genotype and T allele are risk factors for ischemic stroke. It exists interactions between smoking, alcohol abuse, diabetes mellitus and MTHFR gene in the pathogenesis of ischemic stroke.

[Detecting the polymorphism of methylenetetrahydrofolate reductase gene by denaturing high performance liquid chromatography].

OBJECTIVE: To establish a method for detecting the polymorphism of methylenetetrahydrofolate reductase gene (MTHFR). METHODS: The MTHFR was amplified, and the amplified products were detected by denaturing high performance liquid chromatography (DHPLC), and the amplified MTHFR was confirmed by sequencing and restriction enzyme digesting. RESULTS: A total of 334 individuals of Han people in southern China were recruited in our study, and their polymorphisms of MTHFR were detected. The accurate rate of the DHPLC method, that was very sensitive with 100% detection rate available, was over 99%. The frequencies of CC, CT and TT genotypes were 56.9%, 38.3% and 4.8% individually, and the frequencies of T and C alleles were 23.95% and 76.05% individually. CONCLUSION: The DHPLC method can detect polymorphism of MTHFR rapidly, effectively and economically. And there is the existence of different MTHFR polymorphisms in area and race.

[Transplantation of 3H-thymidine-labeled human bone marrow-derived mesenchymal stem cells in mdx mice].

OBJECTIVE: To investigate the feasibility of using human bone marrow-derived mesenchymal stem cells (hBM- MSCs) for repairing the skeletal muscle sarcolemma lesions in mdx mice and characterize the distribution of the transplanted hBM-MSCs. METHODS: Eighteen 8- to 10-week-old immunosuppressed mdx mice received transplantation with 1x10(7) of hBM-MSCs (the fifth passage) with 3H-thymidine (3H-TdR) labeling by injection of the cells into the tail vein. The mice were killed at 24 h, 48 h, 2 weeks, and 1, 2 and 4 months after the transplantation, respectively, to measure the radioactivity in the tissues and organs. Dystrophin expression on the sarcolemma was detected by immunofluorescence analysis. RESULTS: One month after transplantation, the mice with cell transplantation showed greater radioactivity in most of the tissues and organs than the control mice, especially in the bone marrow, liver and spleen. The radioactivity was then gradually lowered but in the skeletal muscle, the radioactivity increased progressively since 2 weeks after transplantation, reaching the peak of 27.65+/-3.53 Bq/mg at 1 month. Compared with that in the control mice, the radioactivity in the bone marrow and skeletal muscle was persistently higher in mice with cell transplantation 1 month after transplantation. No dystrophin-positive cells were found in the mdx mice at 2 weeks but detected at 1 month. The percentage of dystrophin-positive fibers in each section ranged from a 6.6% (1 month) to 8.9% (4 months). CONCLUSIONS: hBM-MSCs engrafted in immunosuppressed mdx mice may differentiate into skeletal muscle cells to repair the pathological lesion of the skeletal muscle sarcolemma. The hBM-MSCs reside mainly in the bone marrow, liver and spleen in the early stage following transplantation, homing into the bone marrow and skeletal muscle later.

[Application of the Bgl II-Bln I dosage test to gene diagnosis of facioscapulohumeral muscular dystrophy 1A gene].

OBJECTIVE: To increase the sensitivity and specificity of conventional gene diagnosis of facioscapulohumeral muscular dystrophy 1A(FSHD1A) by analyzing the distribution of translocation between chromosomes 4q35 and 10q26 in suspected FSHD cases. METHODS: The Bgl II- Bln I dosage test was performed to detect translocation between chromosomes 4q35 and 10q26 in 7 cases of presymptomatic FSHD patients showing positive result in gene diagnosis and 5 cases of sporadic FSHD patients showing negative result in gene diagnosis. DNA samples were digested with Bgl II and Bln I, followed by agrose gel electrophoresis. Probe p13E-11 was labeled with alpha-(32) P dCTP, followed by Southern hybridization. Then the ratio between the chromosomes 4 and 10 derived signal intensities was judged and hence was made known whether there was interchromosomal translocation between chromosomes 4 and 10. RESULTS: The Bgl II-Bln I dosage test revealed a translocation from chromosome 4q35 to 10q26 in one presymptomatic FSHD patient, thus indicating the result of gene diagnosis for her might be false positive. There was one translocation from chromosome 10q26 to 4q35 detected in one sporadic FSHD patient, indicating the result of gene diagnosis for her might be false negative. There were no translocations between chromosomes 4 and 10 in the other 10 cases. CONCLUSION: The Bgl II-Bln I dosage test can detect the translocation between chromosomes 4q35 and 10q26. It can improve the accuracy of the conventional method for gene diagnosis of FSHD1A.

[Translocation between chromosomes 4q35 and 10q26 in facioscapulohumeral muscular dystrophy].

OBJECTIVE: To investigate the distribution of translocation between chromosomes 4q35 and 10q26 in facioscapulohumeral muscular dystrophy (FSHD) patients and normal individuals. METHODS: The Bgl II-Bln I dosage test was performed to study the distribution of translocation between chromosomes 4q35 and 10q26 in 70 cases of FSHD patients, 55 cases of kindred with FSHD, and 52 cases of normal controls. RESULTS: (1) In normal individuals, the frequency of translocation between chromosomes 4q35 and 10q26 is 19.23%. The frequency of translocation from chromosome 4q35 to 10q26 and that from chromosome 10q26 to 4q35 are both 9.62%. (2) In the FSHD patients, the frequency of translocation between chromosomes 4q35 and 10q26 is 18.57%. The frequency of translocation from chromosome 4q35 to 10q26 and that from chromosome 10q26 to 4q35 are 12.86% and 5.71% respectively. CONCLUSIONS: The translocation between chromosomes 4q35 and 10q26 was frequently observed in both normal Chinese population and FSHD patients. No significant difference was observed between them.