Gong Y

LDL Receptor-Related Protein 5 (LRP5) Affects Bone Accrual and Eye Development

In humans, low peak bone mass is a significant risk factor for osteoporosis. We report that LRP5, encoding the low-density lipoprotein receptor-related protein 5, affects bone mass accrual during growth. Mutations in LRP5 cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (OPPG). We find that OPPG carriers have reduced bone mass when compared to age- and gender-matched controls. We demonstrate LRP5 expression by osteoblasts in situ and show that LRP5 can transduce Wnt signaling in vitro via the canonical pathway. We further show that a mutant-secreted form of LRP5 can reduce bone thickness in mouse calvarial explant cultures. These data indicate that Wnt-mediated signaling via LRP5 affects bone accrual during growth and is important for the establishment of peak bone mass.

HMGA2 overexpression-induced ovarian surface epithelial transformation is mediated through regulation of EMT genes.

The AT-hook transcription factor HMGA2 is an oncogene involved in the tumorigenesis of many malignant neoplasms. HMGA2 overexpression is common in both early and late-stage high-grade ovarian serous papillary carcinoma. To test whether HMGA2 participates in the initiation of ovarian cancer and promotion of aggressive tumor growth, we examined the oncogenic properties of HMGA2 in ovarian surface epithelial (OSE) cell lines. We found that introduction of HMGA2 overexpression was sufficient to induce OSE transformation in vitro. HMGA2-mediated OSE transformation resulted in tumor formation in the xenografts of nude mice. By silencing HMGA2 in HMGA2-overexpressing OSE and ovarian cancer cell lines, the aggressiveness of tumor cell growth behaviors was partially suppressed. Global gene profiling analyses revealed that HMGA2-mediated tumorigenesis was associated with expression changes of target genes and microRNAs that are involved in epithelial-to-mesenchymal transition (EMT). Lumican, a tumor suppressor that inhibits EMT, was found to be transcriptionally repressed by HMGA2 and was frequently lost in human high-grade serous papillary carcinoma. Our findings show that HMGA2 overexpression confers a powerful oncogenic signal in ovarian cancers through the modulation of EMT genes.

Berberine induces p53-dependent cell cycle arrest and apoptosis of human osteosarcoma cells by inflicting DNA damage

Alkaloid berberine is widely used for the treatment of diarrhea and other diseases. Many laboratory studies showed that it exhibits anti-proliferative activity against a wide spectrum of cancer cells in culture. In this report we studied the mechanisms underlying the inhibitory effects of berberine on human osteosarcoma cells and on normal osteoblasts. The inhibition was largely attributed to cell cycle arrest at G1 and G2/M, and to a less extent, to apoptosis. The G1 arrest was dependent on p53, as G1 arrest was abolished in p53-deficient osteosarcoma cells. The induction of G1 arrest and apoptosis was accompanied by a p53-dependent up-regulation of p21 and pro-apoptotic genes. However, the G2/M arrest could be induced by berberine regardless of the status of p53. Interestingly, DNA double-strand breaks, as measured by the phosphorylation of H2AX, were remarkably accumulated in berberine-treated cells in a dose-dependent manner. Thus, one major mechanism by which berberine exerts its growth-inhibitory effect is to inflict genomic lesions on cells, which in turn trigger the activation of p53 and the p53-dependent cellular responses including cell cycle arrest and apoptosis.

Lack of association between ADAM33 gene and asthma in a Chinese population.

Asthma is a complex polygenic disease with gene–environment interactions being important. It has been previously suggested that ADAM33, which is a member of a gene family that encodes membrane‐anchored proteins with a disintegrin and a metalloprotease domain, is primarily expressed in lung fibroblasts and bronchial smooth muscle cells and has been associated with airway remodelling and bronchial hyperresponsiveness. A significant association has previously been demonstrated between single nucleotide polymorphisms (SNPs) and haplotypes of the ADAM33 and asthma in ethnically diverse populations. To assess whether SNPs or haplotypes of ADAM33 are related to asthma in a Chinese Han population, we genotyped three SNPs of ADAM33 (7575G/A in intron 6, 11188A/T in intron 19, and 12433T/C in exon 20) in a case‐control study involving 296 patients with asthma and 270 healthy controls. No significant association was detected between these three SNPs and asthma susceptibility in the Chinese population.

Genetic study of indirect inguinal hernia.

We performed a genetic analysis of 280 families with congenital indirect inguinal hernia ascertained in Shandong province. The multifactorial threshold model and segregation analysis were applied to these families to investigate the mode of inheritance of congenital indirect inguinal hernia. Our results indicate that congenital indirect inguinal hernia is not compatible with a multifactorial threshold model, and the frequent vertical transmission and high segregation ratio suggest autosomal dominant inheritance with incomplete penetrance and sex influence. Through further pedigree analysis of the multiple case families with at least two closely related affected members, we noted preferential paternal transmission of the disease gene, which might suggest the role of genomic imprinting in the aetiology of this condition.

A novel mutation of keratin 9 in epidermolytic palmoplantar keratoderma combined with knuckle pads

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominantly inherited disease. We studied a family from Shandong, China, having patients suffering from EPPK with a unique symptom—knuckle pads. We noticed that both the hyperkeratosis and knuckle pads in the Chinese family were friction‐related. Candidate gene analysis was carried out using linkage analysis and direct sequencing. A novel L160F mutation in keratin 9 was found, and its effects on the secondary structure of keratin 9 were studied. We predict that the L160F mutation is also responsible for the knuckle pads in the family. Our study provides a new clue for the study of the function of keratin 9.

Absence of association between two insertion/deletion coding genetic polymorphisms of TIM-1 gene and asthma in Chinese Han population

TIM‐1, a member of T‐cell immunoglobulin domain and mucin domain (TIM) gene family, was implicated as an asthma susceptibility gene in previous studies. TIM‐1 was expressed on CD4+ T cells after activation and its expression was sustained preferentially in T‐helper type 2 (TH2) but not in TH1 cells, therefore TIM‐1 became a good candidate gene for atopic diseases. Recent studies indicated that two insertion/deletion (ins/del) coding genetic polymorphisms in exon 4 of TIM‐1 were associated with asthma susceptibility in some but not in all populations. In order to investigate the relationship between TIM‐1 genetic polymorphisms and asthma in Chinese Han population, we performed a case‐control study for two insertion/deletion polymorphisms in TIM‐1 exon 4 (5383_5397ins/del and 5509_5511delCAA) and a single nucleotide polymorphism (SNP) in intron 8 (IVS 8+9 G/A) between a healthy control group of 309 people and an asthma patient group of 352 people recruited from Chinese Han population. The polymorphisms were genotyped and the allele and genotype frequencies were analysed, but none of the three polymorphisms showed association with asthma susceptibility in single‐locus association analyses. Linkage disequilibrium (LD) analyses demonstrated that the two insertion/deletion polymorphisms were in strong LD but the haplotypes constructed from these two polymorphisms showed no significant association with asthma. In conclusion, our findings suggest that 5383_5397ins/del, 5509_5511delCAA and SNP IVS 8+9 G/A polymorphisms are not associated with asthma susceptibility in Chinese Han population.

Artesunate Sensitizes Ovarian Cancer Cells to Cisplatin by Downregulating RAD51

Artesunate, a semi-synthetic derivative of arteminisin originally developed for the treatment of malaria, has recently been shown to possess antitumor properties. One of the cytotoxic effects of artesunate on cancer cells is mediated by induction of oxidative stress and DNA double-strand breaks (DSBs). We report here that in addition to inducing oxidative stress and DSBs, artesunate can also downregulate RAD51 and impair DSB repair in ovarian cancer cells. We observed that the formation of RAD51 foci and homologous recombination repair (HRR) were significantly reduced in artesunate-treated cells. As a consequence, artesunate and cisplatin synergistically induced DSBs and inhibited the clonogenic formation of ovarian cancer cells. Ectopic expression of RAD51 was able to rescue the increased chemosensitivity conferred by artesunate, confirming that the chemosensitizing effect of artesuante is at least partially mediated by the downregulation of RAD51. Our results indicated that artesunatecan compromise the repair of DSBs in ovarian cancer cells, and thus could be employed as a sensitizing agent in chemotherapy.

ETS1 variants confer susceptibility to ankylosing spondylitis in Han Chinese

IntroductionETS1 is a negative regulator of the Th17 differentiation gene and plays a central role in the pathogenesis of autoimmune diseases. We aimed to investigate whether polymorphisms in ETS1 confer susceptibility to ankylosing spondylitis (AS) in Han Chinese.MethodsWe selected seven single nucleotide polymorphisms (SNPs) within ETS1 based on HapMap data and previous genome-wide association study. Genotyping involved the TaqMan method in 1,015 patients with AS and 1,132 healthy controls from Shandong Province, and 352 AS patients and 400 healthy controls from Ningxia, a northwest region in China. Gene expression was determined by real-time PCR.ResultsThe SNP rs1128334 was strongly associated with AS (odds ratio 1.204, 95% confidence interval 1.06-1.37; Pu2009=u20090.005). This association was confiexrmed in the Ningxia population (Pu2009=u20090.015). Carriers of the haplotype TAT for rs12574073, rs1128334 and rs4937333 were associated with increased risk of AS and haplotype CGC with reduced risk as compared to controls. In addition, ETS1 expression was lower in AS patients than controls. The risk allele A of rs1128334 and haplotype A-T of rs1128334 and rs4937333 were associated with decreased expression of ETS1.ConclusionsCommon variants in ETS1 may contribute to AS susceptibility in Han Chinese people.

Evidence for genetic association of CARD9 and SNAPC4 with ankylosing spondylitis in a Chinese Han population.

Objective. A genome-wide association study and 2 replication studies identified 2 single-nucleotide polymorphisms (SNP) of caspase recruitment domain-containing protein 9 (CARD9) and small nuclear RNA-activating complex polypeptide 4 (SNAPC4) at Chr 9q34.3 associated with ankylosing spondylitis (AS) in whites. We explored a possible association of SNP in CARD9 and SNAPC4 and AS in a Chinese Han population from Shandong. Methods. The study included 1150 patients with AS and 1120 healthy controls who underwent genotyping for 4 SNP of CARD9 and 2 of SNAPC4; we replicated the results in another 490 patients and 380 healthy controls of Ningxia Han Chinese during the same time. We used quantitative real-time PCR (qRT-PCR) to measure CARD9 and SNAPC4 mRNA expression in peripheral leukocytes from 44 patients and 36 controls and allele-specific mRNA expression of CARD9 and SNAPC4 in leukocytes from 130 controls. Results. We validated that an SNP in SNAPC4, rs11145835, was significantly associated with AS in our Chinese Han population (p = 0.001) and replicated the association in samples from the Chinese Ningxia Han population (p = 0.002). Carrying the G allele of rs11145835 was associated with increased risk of AS (OR 1.34, 95% CI 1.12–1.59) and with decreased expression of CARD9 (p = 0.001) and SNAPC4 (p = 0.02) in leukocytes. SNAPC4 mRNA expression was lower in leukocytes from patients than from controls (p = 0.0002). Conclusion. Our study confirmed that an SNP rs11145835 in 9q34.3 that harbors CARD9 and SNAPC4 is associated with AS in a Chinese Han population, and rs11145835 in SNAPC4 is a potential causal variant.