The possible role of the peripheral cannabinoid receptor (CB2) in neutrophil migration was investigated by using human promyelocytic HL60 cells differentiated into neutrophil-like cells and human neutrophils isolated from whole blood. Cell surface expression of CB2 on HL60 cells, on neutrophil-like HL60 cells, and on human neutrophils was confirmed by flow cytometry. Upon stimulation with either of the CB2 ligands JWH015 and 2-arachidonoylglycerol (2-AG), neutrophil-like HL60 cells rapidly extended and retracted one or more pseudopods containing F-actin in different directions instead of developing front/rear polarity typically exhibited by migrating leukocytes. Activity of the Rho-GTPase RhoA decreased in response to CB2 stimulation, whereas Rac1, Rac2, and Cdc42 activity increased. Moreover, treatment of cells with RhoA-dependent protein kinase (p160-ROCK) inhibitor Y27632 yielded cytoskeletal organization similar to that of CB2-stimulated cells. In human neutrophils, neither JWH015 nor 2-AG induced motility or morphologic alterations. However, pretreatment of neutrophils with these ligands disrupted N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced front/rear polarization and migration and also substantially suppressed fMLP-induced RhoA activity. These results suggest that CB2 might play a role in regulating excessive inflammatory response by controlling RhoA activation, thereby suppressing neutrophil migration.The peripheral cannabinoid receptor (CB2) 2 was cloned in 1993 (1) after cloning of the central cannabinoid receptor (CB1) in 1990 (2). It has been suggested that the gene encoding CB2 is a protooncogene and that aberrant expression of CB2 in myeloid precursor cells results in the development of leukemia by blocking neutrophil differentiation (3, 4). CB2 is expressed predominantly in immune cells (5), and because of the diversity of immune cells, it is assumed that CB2 is involved in various activities in addition to inhibition of neutrophil differentiation (6 -9). Steffens et al. (10) recently reported that doses of ⌬ 9 -tetrahydrocannabinol (the most psychoactive component of marijuana) too low to have psychotropic effects inhibit the progression of atherosclerosis via immunomodulatory effects on lymphoid and myeloid cells. This report indicates that CB2 may be involved in a wide range of physiologic phenomena related to immunity and that some CB2 ligands may have application in the treatment of inflammatory disease. However, research into CB2 is still in its early stages. In particular, the involvement of only a few molecules, G␣ i /G␣ o protein, phosphatidylinositol 3-kinase (PI3K), and members of the mitogen-activated protein kinase and nuclear factor-B families, in the CB2 signaling pathways has been reported (6 -8, 11).Among the possible roles of CB2 in immunity is the induction of leukocyte migration to sites of infection and inflammation, an important step in the host defense against pathogenic microorganisms. CB2 is a seven-transmembrane, G␣ i /G␣ o protein-coupled receptor, as ar...

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ObjectivesTo evaluate the burden of rare variants in the causative genes for amyotrophic lateral sclerosis (ALS) on the age at onset of ALS in a Japanese case series.MethodsWe conducted whole-exome sequencing analysis of 89 families with familial ALS (FALS) and 410 patients with sporadic ALS (SALS) to identify known pathogenic mutations or rare functionally predicted deleterious variants in the causative genes for ALS. Rare variants (minor allele frequency <1%) with scaled Combined Annotation-Dependent Depletion score >20 were defined as rare functionally predicted deleterious variants. The patients with ALS were classified on the basis of the number of pathogenic and/or rare functionally predicted deleterious variants, and the age at onset was compared among the classified groups.ResultsWhole-exome sequencing analysis revealed known pathogenic mutations or rare functionally predicted deleterious variants in causative genes for ALS in 56 families with FALS (62.9%) and 87 patients with SALS (21.2%). Such variants in multiple genes were identified in seven probands with FALS and eight patients with SALS. The ages at onset in the patients with ALS with multiple variants were significantly earlier than those in other patients with ALS. Even when the patients with known pathogenic mutations were excluded, a significantly earlier onset of the disease was still observed in patients with multiple rare functionally predicted deleterious variants.ConclusionsA substantial number of patients carried rare variants in multiple genes, and the burden of rare variants in the known causative genes for ALS affects the age at onset in the Japanese ALS series.

Minifascicular neuropathy (MN) is an extremely rare developmental malformation in which peripheral nerves are composed of many small fascicles. Only one patient with MN with 46XY gonadal dysgenesis (GD) was found to carry a mutation affecting the start codon in desert hedgehog (DHH). We identified an identical novel rearrangement mutation of DHH in two consanguineous families with MN, confirming mutations in DHH cause MN with 46XY GD. The patients with the 46XY karyotype developed GD, whereas a patient with the 46XX karyotype did not. These findings further support that DHH has important roles in perineural formation and male gonadal differentiation.