Daniel Wai-Hung Ho

Prevalence and Pattern of Lumbar Magnetic Resonance Imaging Changes in a Population Study of One Thousand Forty-Three Individuals

Study Design. A cross-sectional population study of magnetic resonance imaging (MRI) changes. Objective. To examine the pattern and prevalence of lumbar spine MRI changes within a southern Chinese population and their relationship with back pain. Summary of Background Data. Previous studies on MRI changes and back pain have used populations of asymptomatic individuals or patients presenting with back pain and sciatica. Thus, the prevalence and pattern of intervertebral disc degeneration within the population is not known. Methods. Lumbar spine MRIs were obtained in 1043 volunteers between 18 to 55 years of age. MRI changes including disc degeneration, herniation, anular tears (HIZ), and Schmorl’s nodes were noted by 2 independent observers. Differences were settled by consensus. Disc degeneration was graded using Schneiderman’s classification, and a total score (DDD score) was calculated by the summation of the Schneiderman’s score for each lumbar level. A K-mean clustering program was used to group individuals into different patterns of degeneration. Results. Forty percent of individuals under 30 years of age had lumbar intervertebral disc degeneration (LDD), the prevalence of LDD increasing progressively to over 90% by 50 to 55 years of age. There was a positive correlation between the DDD score and low back pain. L5–S1 and L4–L5 were the most commonly affected levels. Apart from the usual patterns of degeneration, some uncommon patternsof degeneration were identified, comprising of subjects with skip level lesions (intervening normal levels) and isolated upper or mid lumbar degeneration. Conclusion. LDD is common, and its incidence increases with age. In a population setting, there is a significant association of LDD on MRI with back pain.

Association of the Asporin D14 Allele with Lumbar-Disc Degeneration in Asians

Lumbar-disc degeneration (LDD) is a polygenic disease. Susceptibility genes reported so far are mainly extracellular matrix proteins. D14 allele of asporin (ASPN) is associated with osteoarthritis (OA). Candidate-gene association studies showed that the D14 allele is also significantly associated with LDD in Chinese and Japanese individuals. Meta-analysis showed that individuals harboring a D14 allele had higher risk with a summary odds ratio of 1.70 (p = 0.000013). ASPN expression in vertebral discs increased with age and degeneration. Our results indicate ASPN is a LDD gene in Asians, and common risk factors may be considered for OA and LDD.

Lumbar disc degeneration is linked to a carbohydrate sulfotransferase 3 variant

Lumbar disc degeneration (LDD) is associated with both genetic and environmental factors and affects many people worldwide. A hallmark of LDD is loss of proteoglycan and water content in the nucleus pulposus of intervertebral discs. While some genetic determinants have been reported, the etiology of LDD is largely unknown. Here we report the findings from linkage and association studies on a total of 32,642 subjects consisting of 4,043 LDD cases and 28,599 control subjects. We identified carbohydrate sulfotransferase 3 (CHST3), an enzyme that catalyzes proteoglycan sulfation, as a susceptibility gene for LDD. The strongest genome-wide linkage peak encompassed CHST3 from a Southern Chinese family–based data set, while a genome-wide association was observed at rs4148941 in the gene in a meta-analysis using multiethnic population cohorts. rs4148941 lies within a potential microRNA-513a-5p (miR-513a-5p) binding site. Interaction between miR-513a-5p and mRNA transcribed from the susceptibility allele (A allele) of rs4148941 was enhanced in vitro compared with transcripts from other alleles. Additionally, expression of CHST3 mRNA was significantly reduced in the intervertebral disc cells of human subjects carrying the A allele of rs4148941. Together, our data provide new insights into the etiology of LDD, implicating an interplay between genetic risk factors and miRNA.

Association between promoter -1607 polymorphism of MMP1 and Lumbar Disc Disease in Southern Chinese

BackgroundMatrix metalloproteinases (MMPs) are involved in the degradation of the extracellular matrix of the intervertebral disc. A SNP for guanine insertion/deletion (G/D), the -1607 promoter polymorphism, of the MMP1 gene was found significantly affecting promoter activity and corresponding transcription level. Hence it is a good candidate for genetic studies in DDD.MethodsSouthern Chinese volunteers between 18 and 55 years were recruited from the population. DDD in the lumbar spine was defined by MRI using Schneidermans classification. Genomic DNA was isolated from the leukocytes and genotyping was performed using the Sequenom® platform. Association and Hardy-Weinberg equilibrium checking were assessed by Chi-square test and Mann-Whitney U test.ResultsOur results showed substantial evidence of association between -1607 promoter polymorphism of MMP1 and DDD in the Southern Chinese subjects. D allelic was significantly associated with DDD (p value = 0.027, odds ratio = 1.41 with 95% CI = 1.04–1.90) while Genotypic association on the presence of D allele was also significantly associated with DDD (p value = 0.046, odds ratio = 1.50 with 95% CI = 1.01–2.24). Further age stratification showed significant genotypic as well as allelic association in the group of over 40 years (genotypic: p value = 0.035, odds ratio = 1.617 with 95% CI = 1.033–2.529; allelic: p value = 0.033, odds ratio = 1.445 with 95% CI = 1.029–2.029). Disc bulge, annular tears and the Schmorls nodes were not associated with the D allele.ConclusionWe demonstrated that individuals with the presence of D allele for the -1607 promoter polymorphism of MMP1 are about 1.5 times more susceptible to develop DDD when compared with those having G allele only. Further association was identified in individuals over 40 years of age. Disc bulge, annular tear as well as Schmorls nodes were not associated with this polymorphism.

Up‐regulation of histone methyltransferase SETDB1 by multiple mechanisms in hepatocellular carcinoma promotes cancer metastasis

Epigenetic deregulation plays an important role in liver carcinogenesis. Using transcriptome sequencing, we examined the expression of 591 epigenetic regulators in hepatitis B‐associated human hepatocellular carcinoma (HCC). We found that aberrant expression of epigenetic regulators was a common event in HCC. We further identified SETDB1 (SET domain, bifurcated 1), an H3K9‐specific histone methyltransferase, as the most significantly up‐regulated epigenetic regulator in human HCCs. Up‐regulation of SETDB1 was significantly associated with HCC disease progression, cancer aggressiveness, and poorer prognosis of HCC patients. Functionally, we showed that knockdown of SETDB1 reduced HCC cell proliferation in vitro and suppressed orthotopic tumorigenicity in vivo. Inactivation of SETDB1 also impeded HCC cell migration and abolished lung metastasis in nude mice. Interestingly, SETDB1 protein was consistently up‐regulated in all metastatic foci found in different organs, suggesting that SETDB1 was essential for HCC metastatic progression. Mechanistically, we showed that the frequent up‐regulation of SETDB1 in human HCC was attributed to the recurrent SETDB1 gene copy gain at chromosome 1q21. In addition, hyperactivation of specificity protein 1 transcription factor in HCC enhanced SETDB1 expression at the transcriptional level. Furthermore, we identified miR‐29 as a negative regulator of SETDB1. Down‐regulation of miR‐29 expression in human HCC contributed to SETDB1 up‐regulation by relieving its post‐transcriptional regulation. Conclusion: SETDB1 is an oncogene that is frequently up‐regulated in human HCCs; the multiplicity of SETDB1 activating mechanisms at the chromosomal, transcriptional, and posttranscriptional levels together facilitates SETDB1 up‐regulation in human HCC. (Hepatology 2016;63:474–487)

TCGA whole-transcriptome sequencing data reveals significantly dysregulated genes and signaling pathways in hepatocellular carcinoma

This study systematically evaluates the TCGA whole-transcriptome sequencing data of hepatocellular carcinoma (HCC) by comparing the global gene expression profiles between tumors and their corresponding nontumorous liver tissue. Based on the differential gene expression analysis, we identified a number of novel dysregulated genes, in addition to those previously reported. Top-listing upregulated (CENPF and FOXM1) and downregulated (CLEC4G, CRHBP, and CLEC1B) genes were successfully validated using qPCR on our cohort of 65 pairs of human HCCs. Further examination for the mechanistic overview by subjecting significantly upregulated and downregulated genes to gene set enrichment analysis showed that different cellular pathways were involved. This study provides useful information on the transcriptomic landscape and molecular mechanism of hepatocarcinogenesis for development of new biomarkers and further in-depth characterization.

Association of High Myopia with Crystallin Beta A4 (CRYBA4) Gene Polymorphisms in the Linkage-Identified MYP6 Locus

Background Myopia is the most common ocular disorder worldwide and imposes tremendous burden on the society. It is a complex disease. The MYP6 locus at 22 q12 is of particular interest because many studies have detected linkage signals at this interval. The MYP6 locus is likely to contain susceptibility gene(s) for myopia, but none has yet been identified. Methodology/Principal Findings Two independent subject groups of southern Chinese in Hong Kong participated in the study an initial study using a discovery sample set of 342 cases and 342 controls, and a follow-up study using a replication sample set of 316 cases and 313 controls. Cases with high myopia were defined by spherical equivalent ≤ -8 dioptres and emmetropic controls by spherical equivalent within ±1.00 dioptre for both eyes. Manual candidate gene selection from the MYP6 locus was supported by objective in silico prioritization. DNA samples of discovery sample set were genotyped for 178 tagging single nucleotide polymorphisms (SNPs) from 26 genes. For replication, 25 SNPs (tagging or located at predicted transcription factor or microRNA binding sites) from 4 genes were subsequently examined using the replication sample set. Fisher P value was calculated for all SNPs and overall association results were summarized by meta-analysis. Based on initial and replication studies, rs2009066 located in the crystallin beta A4 (CRYBA4) gene was identified to be the most significantly associated with high myopia (initial study: P = 0.02; replication study: P = 1.88e-4; meta-analysis: P = 1.54e-5) among all the SNPs tested. The association result survived correction for multiple comparisons. Under the allelic genetic model for the combined sample set, the odds ratio of the minor allele G was 1.41 (95% confidence intervals, 1.21-1.64). Conclusions/Significance A novel susceptibility gene (CRYBA4) was discovered for high myopia. Our study also signified the potential importance of appropriate gene prioritization in candidate selection.

RNA N6‐methyladenosine methyltransferase‐like 3 promotes liver cancer progression through YTHDF2‐dependent posttranscriptional silencing of SOCS2

Epigenetic alterations have contributed greatly to human carcinogenesis. Conventional epigenetic studies have predominantly focused on DNA methylation, histone modifications, and chromatin remodeling. Recently, diverse and reversible chemical modifications of RNAs have emerged as a new layer of epigenetic regulation. N6‐methyladenosine (m6A) is the most abundant chemical modification of eukaryotic messenger RNA (mRNA) and is important for the regulation of mRNA stability, splicing, and translation. Using transcriptome sequencing, we discovered that methyltransferase‐like 3 (METTL3), a major RNA N6‐adenosine methyltransferase, was significantly up‐regulated in human hepatocellular carcinoma (HCC) and multiple solid tumors. Clinically, overexpression of METTL3 is associated with poor prognosis of patients with HCC. Functionally, we proved that knockdown of METTL3 drastically reduced HCC cell proliferation, migration, and colony formation in vitro. Knockout of METTL3 remarkably suppressed HCC tumorigenicity and lung metastasis in vivo. On the other hand, using the CRISPR/dCas9‐VP64 activation system, we demonstrated that overexpression of METTL3 significantly promoted HCC growth both in vitro and in vivo. Through transcriptome sequencing, m6A sequencing, and m6A methylated RNA immuno‐precipitation quantitative reverse‐transcription polymerase chain reaction, we identified suppressor of cytokine signaling 2 (SOCS2) as a target of METTL3‐mediated m6A modification. Knockdown of METTL3 substantially abolished SOCS2 mRNA m6A modification and augmented SOCS2 mRNA expression. We also showed that m6A‐mediated SOCS2 mRNA degradation relied on the m6A reader protein YTHDF2‐dependent pathway. Conclusion: METTL3 is frequently up‐regulated in human HCC and contributes to HCC progression. METTL3 represses SOCS2 expression in HCC through an m6A‐YTHDF2‐dependent mechanism. Our findings suggest an important mechanism of epigenetic alteration in liver carcinogenesis. (Hepatology 2018;67:2254‐2270).

Effect of Physical Restraint Reduction on Older Patients’ Hospital Length of Stay

OBJECTIVES Physical restraints are often used to prevent falls and to secure medical devices in older people in hospitals. Restraint reduction has been advocated on the grounds that physical restraints have negative psychological effects and are not effective in preventing falls. The potential effect of restraint reduction on length of hospital stay (LOS) has not been investigated. This study was undertaken to compare the average length of stay of older patients in a convalescent medical ward setting before and after a restraint reduction program. DESIGN This is a retrospective study. SETTING A convalescent hospital in Hong Kong. PARTICIPANTS This study included 2000 patient episodes. MEASUREMENTS The use of physical restraint, LOS, and clinical outcomes of randomly selected patient episodes in the year before and after the implementation of a restraint reduction program were compared. The clinical outcomes included Modified Functional Ambulatory Categories and modified Barthel index. Subgroup analysis was performed on those with confusion as defined by dementia diagnosis, low abbreviated mental test score, or abnormal mental domain of Norton Score. RESULTS A total of 958 and 988 patient episodes admitted to 10 medical wards in a convalescent hospital in 2007 and 2009 were examined. There were no significant differences in the baseline characteristics of patients in the 2 years. With the implementation of the restraint reduction scheme, the rate of physical restraint use declined significantly from 13.3% in 2007 to 4.1% in 2009 for all patients. The average LOS of patients was significantly lower in the year after the implementation of restraint reduction (19.5 ± 20.7 versus 16.8 ± 13.4 days in 2007 and 2009 respectively, P < .001). On subgroup analysis, the reduction in LOS was significant in the cognitively impaired patients (23.0 ± 26.5 to 17.8 ± 15.0 days in 2007 and 2009 respectively, P < .001), but not in the cognitively normal patients. There were no significant differences between the 2 years in the incidence of fall, mobility, and activities of daily living on discharge. CONCLUSION Physical restraint reduction was associated with significant reduction in average length of stay in convalescent medical wards, especially in the cognitively impaired patients.

TSC1/2 mutations define a molecular subset of HCC with aggressive behaviour and treatment implication

Objective We investigated the mutational landscape of mammalian target of rapamycin (mTOR) signalling cascade in hepatocellular carcinomas (HCCs) with chronic HBV background, aiming to evaluate and delineate mutation-dependent mechanism of mTOR hyperactivation in hepatocarcinogenesis. Design We performed next-generation sequencing on human HCC samples and cell line panel. Systematic mutational screening of mTOR pathway-related genes was undertaken and mutant genes were evaluated based on their recurrence. Protein expressions of tuberous sclerosis complex (TSC)1, TSC2 and pRPS6 were assessed by immunohistochemistry in human HCC samples. Rapamycin sensitivity was estimated by colony-formation assay in HCC cell lines and the treatment was further tested using our patient-derived tumour xenograft (PDTX) models. Results We identified and confirmed multiple mTOR components as recurrently mutated in HBV-associated HCCs. Of significance, we detected frequent (16.2%, n=18/111) mutations of TSC1 and TSC2 genes in the HCC samples. The spectrum of TSC1/2 mutations likely disrupts the endogenous gene functions in suppressing the downstream mTOR activity through different mechanisms and leads to more aggressive tumour behaviour. Mutational disruption of TSC1 and TSC2 was also observed in HCC cell lines and our PDTX models. TSC-mutant cells exhibited reduced colony-forming ability on rapamycin treatment. With the use of biologically relevant TSC2-mutant PDTXs, we demonstrated the therapeutic benefits of the hypersensitivity towards rapamycin treatment. Conclusions Taken together, our findings suggest the significance of previously undocumented mutation-dependent mTOR hyperactivation and frequent TSC1/2 mutations in HBV-associated HCCs. They define a molecular subset of HCC having genetic aberrations in mTOR signalling, with potential significance of effective specific drug therapy.