Genome-wide search for strabismus susceptibility loci.

The purpose of this study was to search for chromosomal susceptibility loci for comitant strabismus. Genomic DNA was isolated from 10mL blood taken from each member of 30 nuclear families in which 2 or more siblings are affected by either esotropia or exotropia. A genome-wide search was performed with amplification by polymerase chain reaction of 400 markers in microsatellite regions with approximately 10 cM resolution. For each locus, non-parametric affected sib-pair analysis and non-parametric linkage analysis for multiple pedigrees (Genehunter software, http://linkage.rockefeller.edu/soft/) were used to calculate multipoint lod scores and non-parametric linkage (NPL) scores, respectively. In sib-pair analysis, lod scores showed basically flat lines with several peaks of 0.25 on all chromosomes. In non-parametric linkage analysis for multiple pedigrees, NPL scores showed one peak as high as 1.34 on chromosomes 1, 2, 4, 7, 10, 15, and 16, while 2 such peaks were found on chromosomes 3, 9, 11, 12, 18, and 20. Non-parametric linkage analysis for multiple pedigrees of 30 families with comitant strabismus suggested a number of chromosomal susceptibility loci. Our ongoing study involving a larger number of families will refine the accuracy of statistical analysis to pinpoint susceptibility loci for comitant strabismus.&#60;/P&#62;</p

ARIX and PHOX2B polymorphisms in patients with congenital superior oblique muscle palsy.

To identify ARIX gene and PHOX2B gene polymorphisms in patients with congenital superior oblique muscle palsy, 3 exons of the ARIX gene and PHOX2B gene were sequenced by genomic DNA amplification with polymerase chain reaction (PCR) and direct sequencing in 31 patients with congenital superior oblique muscle palsy and in 54 normal individuals. A family with a father and one daughter each having congenital superior oblique muscle palsy was also included in this study. Eleven patients with congenital superior oblique muscle palsy had heterozygous nucleotide changes in the ARIX gene, including 4 patients reported on previously. One patient with atrophy of the superior oblique muscle had a new change of T-4G in the promoter region of the ARIX gene. The other 6 patients had a heterozygous nucleotide change of G153A in the 5'-untranslated region (UTR) of the exon 1 of the ARIX gene. These nucleotide changes of the ARIX gene, taken together, had a significant association with congenital superior oblique muscle palsy(P = 0.0022). One patient and 5 patients had heterozygous nucleotide changes of A1106 C and A1121 C in exon 3 of the PHOX2B gene, respectively, while these changes were absent in the normal individuals. Two patients had both the G153A change in the 5'-UTR of exon 1 of the ARIX gene and the A1121 C change in exon 3 of the PHOX2B gene. In conclusion, the polymorphisms of the ARIX gene and PHOX2B gene may be genetic risk factors for the development of congenital superior oblique muscle palsy.</p

Human bone marrow VCAM-1+ macrophages provide a niche for reactive and neoplastic erythropoiesis

Resident bone marrow macrophages provide a microenvironment for erythropoiesis, forming erythroblastic islands (EBIs) via adhesion molecules. In this study, we examined vascular cell adhesion molecule-1 (VCAM-1) expression in human bone marrow specimens using immunohistochemistry. VCAM-1 was strongly expressed in CD169+ macrophages in EBIs and weakly in sinusoidal vascular endothelial cells. In reactive erythropoiesis, including hemolytic and megaloblastic anemia, the extended cytoplasm of VCAM-1+ CD169+ macrophages circumscribed the erythroid cells. The strong affinity between VCAM-1+ macrophages and erythroid cells was also observed in polycythemia vera (PV), essential thrombocythemia (ET), and chronic myelogenous leukemia (CML). VCAM-1 density was significantly higher in PV than in ET and CML (p < 0.001), and correlated with blood erythrocyte count in all three neoplasms (p < 0.001). In ET, the VCAM-1 density was higher in cases with the JAK2 mutation than with the CALR mutation. In myelodysplastic syndrome with erythroid predominance but unclear EBI formation, punctate VCAM-1+ cytoplasmic processes of macrophages were seen between erythroblasts, similar to those seen between granulocytic precursors in CML, suggesting incomplete contact of VCAM-1+ macrophages with dysplastic erythroid cells. These results suggest that VCAM-1+ macrophages create a niche for reactive and neoplastic erythropoiesis and may be a therapeutic target in PV

Sphingosine-1-phosphate receptor 1 expression in angiosarcoma : Possible role in metastasis and a potential therapeutic target

Sphingosine-1-phosphate (S1P) is a potent lipid mediator that has been implicated in the migration of lymphocytes and endothelial cells through S1P receptors. S1PR1 is strongly expressed in angiosarcoma, a malignant tumor of endothelial cell origin that has a high propensity for metastasis and poor prognosis; however, the pathological significance of S1PR1 expression is not clear. In this study, we investigated the effect of S1PR1 modulation on cell migration, and examined its potential role as a therapeutic target against metastatic dissemination of angiosarcoma. S1PR1 expression in the human angiosarcoma cell line MO-LAS was assessed by immunocytochemical examination and Western blotting. Effects of S1PR1- specific small interfering RNA (siRNA) and that of FTY720-P (a functional S1PR1-antagonist) on MO-LAS cell chemotactic migration towards sphingosine-1-phosphate (S1P) or 10% fetal bovine serum (FBS) were assessed by Transwell migration assay; wound healing assays for random cell migration were performed using a live cell analyzer. Immunostaining revealed high expression of S1PR1 on the MO-LAS cell membrane. Transwell and wound-healing assays showed that S1P enhanced chemotactic and random migration of MO-LAS cells, respectively. Inhibition of S1PR1 expression with siRNA significantly attenuated chemotaxis of cells towards S1P and 10% FBS. Further, FTY720-P strongly induced the internalization and degradation of S1PR1 even in the presence of serum containing S1P. It attenuated chemotactic cell migration of MO-LAS towards both S1P and serum, as well as the random motility of cells at nanomolar concentrations. These results suggest that the S1P/S1PR1 axis may be a potential therapeutic target for inhibition of angiosarcoma metastasis by controlling its cell motility

Time-resolved serial femtosecond crystallography reveals early structural changes in channelrhodopsin

X線自由電子レーザーを用いて、光照射によるチャネルロドプシンの構造変化の過程を捉えることに成功. 京都大学プレスリリース. 2021-03-26.Channelrhodopsins (ChRs) are microbial light-gated ion channels utilized in optogenetics to control neural activity with light . Light absorption causes retinal chromophore isomerization and subsequent protein conformational changes visualized as optically distinguished intermediates, coupled with channel opening and closing. However, the detailed molecular events underlying channel gating remain unknown. We performed time-resolved serial femtosecond crystallographic analyses of ChR by using an X-ray free electron laser, which revealed conformational changes following photoactivation. The isomerized retinal adopts a twisted conformation and shifts toward the putative internal proton donor residues, consequently inducing an outward shift of TM3, as well as a local deformation in TM7. These early conformational changes in the pore-forming helices should be the triggers that lead to opening of the ion conducting pore