Haihong Qin

MicroRNA-29b contributes to DNA hypomethylation of CD4+ T cells in systemic lupus erythematosus by indirectly targeting DNA methyltransferase 1

BACKGROUND The mechanism of DNA hypomethylation in systemic lupus erythematosus (SLE) has not been fully elucidated. Recent studies showed that miR-29b could regulate DNA methylation by targeting the DNA methylation machinery. However, the role of miR-29b in T cell aberrant DNA hypomethylation of SLE still remains unclear. OBJECTIVE In this study, we asked whether miR-29b regulate DNA methylation in lupus CD4+ T cells. METHODS The miR-29b expression was analyzed by quantitative polymerase chain reaction (qPCR). Sp1, DNMT1, CD11a and CD70 mRNA and protein levels were determined by qPCR, Western-blotting and flow cytometry, respectively. The global DNA methylation levels were evaluated by the Methyflash™ DNA Methylation Quantification Kit. CD11a and CD70 promoter methyaltion levels were detected by bisulfate modification and methylation-sensitive high resolution melting analysis. RESULTS In SLE patients, the miR-29b levels were up-regulated as compared to healthy donors and its degree of overexpression was negatively correlated with sp1 and DNMT1 protein levels, respectively. Overexpression of miR-29b resulted in significant reduction of sp1 and DNMT1 expression. Further analysis demonstrated that overexpression of miR-29b in CD4+ T cells from healthy donors led to the DNA hypomethylation and up-regulation of genes encoding CD11a and CD70, and inhibition of miR-29b expression in CD4+ T cells from patients with lupus caused reverse effects. CONCLUSION Our study suggests that miR-29b negatively regulates DNMT1 expression by targeting sp1 in T cells. The overexpression of miR-29b contributes to the reduction of DNMT1 levels and thereby DNA hypomethylation in SLE. This finding provides potential novel strategies for therapeutic interventions.

Associations between aberrant DNA methylation and transcript levels of DNMT1 and MBD2 in CD4+T cells from patients with systemic lupus erythematosus

It seems that global DNA hypomethylation in CD4+T cells is linked to the pathogenesis of systemic lupus erythematosus (SLE). However, the underlying mechanism by which SLE patients show hypomethylated DNA remains unclear. This study explored the relationship between DNA methylation patterns and expression levels of DNA methyltransferases (DNMT1) and MBD2 in CD4+T cells of SLE patients.

Effects of ultraviolet B exposure on DNA methylation in patients with systemic lupus erythematosus

The aim of this study was to investigate the effects of ultraviolet B (UVB) exposure on DNA methylation in patients with systemic lupus erythematosus (SLE) and its significance in the pathogenesis of SLE. T cells from 35 SLE patients and 21 healthy individuals were cultured and irradiated with UVB. The global DNA methylation profiles of the T cells obtained from the patients and controls following irradiation with UVB were assessed using specific monoclonal antibodies for 5-methylcytosine and analyzed quantitatively through flow cytometry. Real-time reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the levels of DNA methyltransferase 1 (DNMT1) and methyl CpG binding domain protein 2 (MBD2) in T cells from the patients and controls following UVB irradiation. Significant global DNA hypomethylation was observed in the SLE patients compared with the controls (P<0.01). The SLE patients also had significantly lower levels of DNMT1 mRNA expression (P<0.01) and significantly higher levels of MBD2 mRNA compared with the controls (P<0.01). DNA methylation was decreased following UVB irradiation at two different dosages and the DNA methylation levels of the patients with active SLE were more sensitive to UVB. The level of DNMT1 mRNA was decreased following UVB irradiation at the higher dosage in the patients with active SLE, but no significant difference was observed in MBD2 mRNA expression. UVB exposure is able to inhibit DNA methylation and DNMT1 mRNA expression, which is subsequently involved in the epigenetic mechanism of SLE. The process by which DNA hypomethylation occurs in patients with SLE is complicated and the multiple factors that are involved in DNA methylation and demethylation events require further study.

Icariside II induces apoptosis via inhibition of the EGFR pathways in A431 human epidermoid carcinoma cells

Improvements in skin cancer treatment are likely to derive from novel agents targeting the molecular pathways that promote tumor cell growth and survival. Icariside II (IS) is a metabolite of icariin, which is derived from Herba Epimedii. The aim of the present study was to evaluate the antitumor effects of IS and to determine the mechanism of apoptosis in A431 human epidermoid carcinoma cells. A431 cells were treated with IS (0‑100 µM) for 24 or 48 h and cell viability was detected using the WST‑8 assay. Apoptosis was measured by the Annexin‑V/propidium iodide (PI) flow cytometric assay. Western blot analysis was used to measure the expression of cleaved caspase‑9, cleaved poly ADP ribose polymerase (PARP), phosphorylated signal transducer and activator of transcription 3 (P‑STAT3), phosphorylated extracellular signal-regulated kinase (P‑ERK), and P‑AKT. A431 cells were also pretreated with IS (0‑100 µM) 2 h prior to treatment with epidermal growth factor (EGF; 100 ng/ml) for 10 min. Phosphorylated EGF receptor (P‑EGFR), P‑STAT3, P‑ERK and P‑AKT were detected by western blot analysis. The results demonstrated that IS inhibited the cell viability of the A431 cells in a dose‑dependent manner. Pretreatment with LY294002 [a phosphatidylinositol 3-kinase (PI3K) inhibitor], EGF (an EGFR agonist) and AG1478 (an EGFR inhibitor) partially reversed IS‑induced decreases in cell viability. Treatment with 50 µm IS resulted in an increased number of apoptotic cells mirrored by increases in cleaved caspase‑9 and cleaved PARP. In addition, treatment with 50 µM IS significantly inhibited the activation of the Janus kinase (JAK)‑STAT3 and mitogen‑activated protein kinase (MAPK)‑ERK pathways, but promoted the activation of the PI3K‑AKT pathway. Furthermore, IS effectively inhibited the EGF-induced activation of the EGFR pathways. In conclusion, IS inhibited the cell viability of the A431 cells through the regulation of apoptosis. These effects were mediated, at least in part, by inhibiting the activation of the EGFR pathways.

Ultraviolet B enhances DNA hypomethylation of CD4+ T cells in systemic lupus erythematosus via inhibiting DNMT1 catalytic activity

BACKGROUND CD4+ T cells DNA hypomethylation is involved in the pathogenesis of systemic lupus erythematosus (SLE). Recent studies showed that ultraviolet B (UVB, 290-320 nm) might induce the exacerbation of SLE by decreasing the DNA methylation level. However, the role of DNA methyltransferase 1 (DNMT1) in the UVB-induced CD4+ T cells DNA hypomethylation remains unclear. OBJECTIVE To elucidate the role of DNMT1 in lupus CD4+ T cells global DNA hypomethylation enhanced by UVB. METHODS 35 SLE patients and 15 healthy controls were enrolled in the study. CD4+ T cells from SLE patients and healthy controls exposed to different dosages of UVB were analyzed. The global DNA methylation measurement, real-time PCR, Western blotting and DNMT1 catalytic activity detection were employed. RESULTS The level of global DNA methylation and DNMT1 mRNA expression in CD4+ T cells from SLE patients were significantly lower than those from the control group. DNA methylation was decreased after UVB exposure in a dosage-dependent manner in SLE patients, but not in the control group. DNMT1 mRNA and protein expression level were not affected by UVB exposure in both SLE patients and healthy controls. DNMT1 catalytic activity was significantly decreased in CD4+ T cells from SLE patients after UVB exposure in a dosage-dependent manner. DNMT1 catalytic activity was lower and more sensitive to UVB exposure in CD4+ T cells from active SLE patients that from stable ones. CONCLUSION UVB enhanced DNA hypomethylation of CD4+ T cells in SLE via inhibiting DNMT1 catalytic activity in a dosage-dependent manner.

Elevated expression of miR-142-3p is related to the pro-inflammatory function of monocyte-derived dendritic cells in SLE

BackgroundRecent studies have shown that alterations in the function of dendritic cells (DCs) are involved in the pathogenesis of systemic lupus erythematosus (SLE). However, the mechanism of the alteration remains unclear.MethodsWe cultured monocyte-derived DCs (moDCs) in vitro and examined the cytokines and chemokines in the supernatants of moDCs in negative controls (NC) and SLE patients in active phase. We then profiled microRNAs (miRNAs) of LPS-stimulated moDCs in SLE patients and used real-time PCR to verify the differentially expressed miRNAs. A lentiviral construct was used to overexpress the level of miR-142-3p in moDCs of NC. We examined the cytokines and chemokines in the supernatants of moDCs overexpressing miR-142-3p and used Transwell test, flow cytometric analysis and cell proliferation to observe the impact on CD4+ T cells in moDC-CD4+T cell co-culture.ResultsmoDCs in patients with SLE secreted increased level of IL-6, CCL2 and CCL5, with attraction of more CD4+ T cells compared with NC. We found 18 differentially expressed microRNAs in moDCs of SLE patients by microarray, and target gene prediction showed some target genes of differentially expressed miRNAs were involved in cytokine regulation. miR-142-3p was verified among the highly expressed miRNAs in the SLE group and overexpressing miR-142-3p in moDCs of the NC group caused an increase of SLE-related cytokines, such as CCL2, CCL5, CXCL8, IL-6 and TNF-α. Moreover, moDCs overexpressed with miR-142-3p resulted in attraction of an increased number of CD4+ T cells and in suppression of the proportion of Tregs in DC-CD4+T cell co-culture whereas the proliferation of CD4+T cells was not altered.ConclusionsThe results demonstrated a role for miR-142-3p in regulating the pro-inflammatory function of moDCs in the pathogenesis of SLE. These findings suggested that miR-142-3p could serve as a novel therapeutic target for the treatment of SLE.

Paeoniflorin attenuates ultraviolet B-induced apoptosis in human keratinocytes by inhibiting the ROS-p38-p53 pathway.

Ultraviolet (UV) light is one of the most harmful environmental factors that contribute to skin damage. Exposure to UV induces extensive generation of reactive oxygen species (ROS), and results in photoaging and skin cancer development. One approach to protecting human skin against UV radiation is the use of antioxidants. In recent years, naturally occurring herbal compounds have gained considerable attention as protective agents for UV exposure. Paeoniflorin (PF) is a novel natural antioxidant, which is isolated from peony root (Radix Paeoniae Alba). The present study evaluated the protective effects of PF on UV‑induced skin damage in vitro, and demonstrated that the effects were mediated via the ROS‑p38‑p53 pathway. The results of the present study demonstrated that treatment with PF (25, 50, and 100 µM) significantly increased the percentage of viable keratinocytes after UV‑B exposure. In addition, cell death analysis indicated that PF treatment markedly reduced UV‑B‑radiation‑induced apoptosis in keratinocytes, which was accompanied by increased procaspase 3 expression and decreased cleaved caspase 3 expression. Treatment with PF markedly reduced the production of ROS, and inhibited the activation of p38 and p53 in human keratinocytes, thus suggesting that the ROS‑p38‑p53 pathway has a role in UV‑B‑induced skin damage. In conclusion, the present study reported that PF was able to attenuate UV‑B‑induced cell damage in human keratinocytes. Notably, these effects were shown to be mediated, at least in part, via inhibition of the ROS-p38-p53 pathway.

The Role of Autophagy in the Resistance to BRAF Inhibition in BRAF-Mutated Melanoma

Malignant melanoma is the most aggressive and notorious skin cancer, and metastatic disease is associated with very poor long-term survival outcomes. Although metastatic melanoma patients with oncogenic mutations in the BRAF gene initially respond well to the treatment with specific BRAF inhibitors, most of them will eventually develop resistance to this targeted therapy. As a highly conserved catabolic process, autophagy is responsible for the maintenance of cellular homeostasis and cell survival, and is involved in multiple diseases, including cancer. Recent study results have indicated that autophagy might play a decisive role in the resistance to BRAF inhibitors in BRAF-mutated melanomas. In this review, we will discuss how autophagy is up-regulated by BRAF inhibitors, and how autophagy induces the resistance to these agents.

Association of TNFAIP3 and TNIP1 polymorphisms with systemic lupus erythematosus risk: A meta-analysis

OBJECT With the development of GWAS, both TNFAIP3 and TNIP1 were revealed to be susceptibility genes of SLE. However, some other studies revealed no association between TNFAIP3, TNIP1 and SLE susceptibility. In order to estimate such association more precisely and systemically, a meta-analysis was conducted. METHOD Studies on the association between TNFAIP3 rs2230926, TNIP1 rs7708392 and SLE risk were carefully selected via searching 3 databases (Pubmed, Embase, and Web of Science). A fixed- or random-effect model was used according to the heterogeneity, and a subgroup analysis by ethnicity was also performed. RESULTS 26 studies from 18 articles involving a total of 21,372 patients and 30,165 controls were analyzed for TNFAIP3 rs2230926. A significant association between the minor G allele of TNFAIP3 rs2230926 and SLE risk was found via a random-effect model (OR = 1.643, 95% CI = (1.462, 1.847), p < 0.01). In the subgroup analysis by ethnicity, significant correlations were also found in all Caucasians, Asians, and Africans (OR = 1.675, 95% CI = (1.353, 2.074), p < 0.01; OR = 1.738, 95% CI = (1.557, 1.940), p < 0.01; OR = 1.324, 95% CI = (1.029, 1.704), p < 0.05). As for TNIP1 rs7708392, 21 studies from 12 articles involving 24,716 cases and 32,200 controls were analyzed. A significant association of the minor C allele of TNIP1 rs7708392 and SLE risk was found via a random-effect model (OR = 1.247, 95% CI = (1.175, 1.323), p < 0.01). In the subgroup analysis by ethnicity, significant correlations were found in Caucasians, and Africans (OR = 1.317, 95% CI = (1.239, 1.401), p < 0.01; OR = 1.210, 95% CI = (1.108, 1.322), p < 0.01). However, there was no significant association in Asians (OR = 1.122, 95% CI = (0.953, 1.321), p > 0.05). CONCLUSION The minor G allele of TNFAIP3 rs2230926 was associated with increased risk of SLE in all Caucasians, Asians, and Africans. The minor C allele of TNIP1 rs7708392 was associated with the increased risk of SLE in Caucasians and Africans, while it was not associated with SLE susceptibility in Asians.

Recurrent cutaneous malignant fibrous histiocytoma

Auteur(s) : Wei-Min Shi1, Wan-Qing Liao2, Zhou-Wei Wu1, Prajwal Pandey1, Xing-Yu Mei1, Hai-Hong Qin1, Jin-Hua Xu3, Liangliang Shen1 1Dermatology Department, Tong Ji Hospital, Tong Ji University, Shanghai 200065, China 2Dermatology Department, Chang Zheng Hospital, Secondary Military Medical University, Shanghai 200003, China 3Dermatology Department, Hua Shan Hospital, Fu Dan University, Shanghai 200040, China Malignant fibrous histiocytoma (MFH) is a common soft tissue sarcoma occurring on the [...]