UHMK1

Abstract: UHMK1 has previously been implicated as a susceptibility gene for schizophrenia in the 1q23.3 region by significant evidence of allelic and haplotypic association between schizophrenia and several genetic markers at UHMK1 in a London-based case-control sample. Further fine mapping of the UHMK1 gene locus in the University College London schizophrenia case-control sample was carried out with tagging SNPs. Two additional SNPs were found to be associated with schizophrenia (rs6604863 P = 0.02, rs10753578 P = 0.017). Tests of allelic and haplotypic association were then carried out in a second independent sample from Aberdeen consisting of 858 individuals with schizophrenia and 591 controls. Two of these SNPs also showed association in the Aberdeen sample (rs7513662 P = 0.0087, rs10753578 P = 0.022) and several haplotypes were associated (global permutation P = 0.0004). When the UCL and Aberdeen samples were combined three SNPs (rs7513662 P = 0.0007, rs6427680 P = 0.0252, rs6694863 P = 0.015) and several haplotypes showed association (eg HAP-A, HAP-B, HAP-C permutation P = 0.00005). The finding of allelic association with markers in the UHMK1 gene might help explain why it has not been possible, despite great effort, to satisfactorily confirm previously reported associations between schizophrenia and the genes RGS4 and NOS1AP/CAPON. These genes flank UHMK1 and all three loci are within a 700 kb region showing linkage to schizophrenia. The confirmation of association between UHMK1 and schizophrenia, rather than RGS4 and NOS1AP in the London sample, points to the possibility that previous efforts to accurately fine map a gene in the 1q23.3 region have lacked accuracy or may have suffered from methodological flaws.

Abstract: Family based linkage studies have confirmed that part of chromosome lq23.3 contains a susceptibility gene for schizophrenia. This region was investigated by tests of allelic and haplotypic association in order to fine map a specific gene in the lq23.3 region. Previously published studies claimed that the genes RGS4 and CAPON on lq23.3 were associated with schizophrenia. For this research thesis multiple markers were genotyped at the RGS4 and CAPON loci in a London based case control sample, no evidence for association was found. Therefore further fine mapping was carried out in the region between the RGS4 and CAPON genes. Allelic and haplotypic associations with schizophrenia were found with three microsatellite and four SNP markers within the serine threonine kinase (UHMK1) gene. A replication study using an Aberdeen based case control sample also found statistically significant evidence of allelic and haplotypic association between TJHMK1 and schizophrenia. Re-sequencing of the UHMK1 gene was carried out in those individuals who had inherited alleles and haplotypes associated with schizophrenia. Three genetic variants were found. Genotyping of the whole case control sample showed that these changes were not associated with schizophrenia. The previously reported associations between schizophrenia and RGS4 as well as CAPON could possibly be explained by linkage disequilibrium between UHMK1 and both CAPON and RGS4. Alternatively there could be two or even three susceptibility genes within the 700 Kb region. At present no potential aetiological base pair changes have been detected in any of the three genes. UHMK1 is known to be highly expressed in regions of the brain implicated in schizophrenia and was found to be significantly down regulated in mice treated with the antipsychotic drug Clozapine. Further confirmation of the involvement of this gene in schizophrenia is needed followed by further efforts to detect genetic variation in or next to the gene which has an effect on expression and function of UHMK1.

Abstract: OBJECTIVE We aimed to identify a microRNA (miRNA) that is significantly upregulated in blood and in cells of the oral mucosa upon exposure to the periodontitis main risk factors oral inflammation and tobacco smoke, to subsequently identify its target gene and to describe the molecular mechanism of gene regulation. BACKGROUND miRNAs are associated with many disorders. Array-based miRNA expression studies indicated a number of differentially expressed miRNAs in the pathology of oral diseases. However, these miRNAs mostly lacked replication, and their target genes have remained unknown. METHODS 863 miRNAs were analyzed in blood from 18 PD cases and 70 controls (Geniom Biochip). Selected miRNAs were analyzed for upregulation in the inflamed oral mucosa of PD patients using published miRNA expression profiling studies from gingival cells. hsa-miR-374b-5p mimic was overexpressed in primary gingival fibroblasts (pGFs) from 3 donors, and genome-wide mRNA expression was quantified (Clarion Array). Gene-specific regulation was validated by qRT-PCR and Luciferase activity in HeLa cells. RESULTS hsa-miR-374b-5p showed >twofold change (FC) in 3 independent studies performed in blood, gingival tissues, and cells. After hsa-miR-374b-5p overexpression, genome-wide expression analysis showed UHMK1 as top 1 downregulated gene in pGFs (p = 2.5 × 10-04 , fold change = -1.8). Reporter genes demonstrated that hsa-miR-374b-5p downregulates mRNA levels (p = .02; FC = -1.5), leading to reduction in protein activity (p = .013, FC = -1.3). CONCLUSIONS hsa-miR-374b-5p is upregulated in blood and ginvial cells exposed to oral inflammation and tobacco smoke and regulates UHMK1, which has a role in osteoclast differentiation.