m6A demethylation of FOSL1 mRNA protects hepatoma cells against necrosis under glucose deprivation.

Stress-adaptive mechanisms enabling cancer cells to survive under glucose deprivation remain elusive. N6-methyladenosine (m6A) modification plays important roles in determining cancer cell fate and cellular stress response to nutrient deficiency. However, whether m6A modification functions in the regulation of cancer cell survival under glucose deprivation is unknown. Here, we found that glucose deprivation reduced m6A modification levels. Increasing m6A modification resulted in increased hepatoma cell necrosis under glucose deprivation, whereas decreasing m6A modification had an opposite effect. Integrated m6A-seq and RNA-seq revealed potential targets of m6A modification under glucose deprivation, including the transcription factor FOSL1; further, glucose deprivation upregulated FOSL1 by inhibiting FOSL1 mRNA decay in an m6A-YTHDF2-dependent manner through reducing m6A modification in its exon1 and 5'-UTR regions. Functionally, FOSL1 protected hepatoma cells against glucose deprivation-induced necrosis in vitro and in vivo. Mechanistically, FOSL1 transcriptionally repressed ATF3 by binding to its promoter. Meanwhile, ATF3 and MAFF interacted via their leucine zipper domains to form a heterodimer, which competed with NRF2 for binding to antioxidant response elements in the promoters of NRF2 target genes, thereby inhibiting their transcription. Consequently, FOSL1 reduced the formation of the ATF3-MAFF heterodimer, thereby enhancing NRF2 transcriptional activity and the antioxidant capacity of glucose-deprived-hepatoma cells. Thus, FOSL1 alleviated the necrosis-inducing effect of glucose deprivation-induced reactive oxygen species accumulation. Collectively, our study uncovers the protective role of m6A-FOSL1-ATF3 axis in hepatoma cell necrosis under glucose deprivation, and may provide new targets for cancer therapy.

[Using Biochar and Iron-calcium Material to Remediate Paddy Soil Contaminated by Cadmium and Arsenic].

In this study, iron-calcium material (FC) and hickory-cattail biochar (BC) were applied to prepare composite material (BF), which was used to repair the combined pollution of cadmium and arsenic in paddy soil to reduce the content of cadmium (Cd) and arsenic (As) in rice grain. Soil pore water, rhizosphere soil, bulk soil, rice plants, and root iron plaque samples were collected during the growth period of rice in a pot experiment to explore the effects and mechanism of FC, BC, and BF on the bioavailability of Cd and As in paddy soil and their contents in plants. The results showed that biochar could significantly (P < 0.05) increase the pH value of bulk soil (0.55-0.66 units) and rhizosphere soil (0.28-0.36 units) and elevate the soil dissolved organic carbon (DOC) content. FC material could significantly (P < 0.05) reduce the pH of bulk soil (0.14-0.27 units) and rhizosphere soil (0.38-0.41 units), as well as the soil DOC content. Iron-calcium materials and composite could simultaneously reduce the contents of available Cd and As in soil pore water, rhizosphere soil, and bulk soil, whereas biochar could reduce the content of Cd but increase the content of As. Among them, a 1% addition of composite had the best effect. The available Cd and As in soil decreased by 41.8%-48.2% and 6.1%-10.1%, respectively. Biochar, iron-calcium materials, and composites improved plant biomass (dry weight of root, stem, leaf, and grain). For example, the dry weights of rice grains under these treatments were higher (48.5%-184.0%) than that of CK, as was the root iron plaque content (7.5%-13.6%). Compared with that in the CK, biochar could effectively reduce the Cd content in rice grain by 21.0%-26.1%. Iron-calcium material and composite could simultaneously reduce the Cd and As contents in rice grain. Among them, the BF treatment had the best effect on the reduction of Cd and As in rice grain, with a decrease of 36.9%-42.0% and 40.4%-44.4%, respectively. The Cd and As contents in rice grain were lower than the national standard values (GB 2762-2017).

Lysyl hydroxylase LH1 promotes confined migration and metastasis of cancer cells by stabilizing Septin2 to enhance actin network.

BACKGROUND: Excessive extracellular matrix deposition and increased stiffness are typical features of solid tumors such as hepatocellular carcinoma (HCC) and pancreatic ductal adenocarcinoma (PDAC). These conditions create confined spaces for tumor cell migration and metastasis. The regulatory mechanism of confined migration remains unclear. METHODS: LC-MS was applied to determine the differentially expressed proteins between HCC tissues and corresponding adjacent tissue. Collective migration and single cell migration microfluidic devices with 6 µm-high confined channels were designed and fabricated to mimic the in vivo confined space. 3D invasion assay was created by Matrigel and Collagen I mixture treat to adherent cells. 3D spheroid formation under various stiffness environment was developed by different substitution percentage GelMA. Immunoprecipitation was performed to pull down the LH1-binding proteins, which were identified by LC-MS. Immunofluorescent staining, FRET, RT-PCR, Western blotting, FRAP, CCK-8, transwell cell migration, wound healing, orthotopic liver injection mouse model and in vivo imaging were used to evaluate the target expression and cellular phenotype. RESULTS: Lysyl hydroxylase 1 (LH1) promoted the confined migration of cancer cells at both collective and single cell levels. In addition, LH1 enhanced cell invasion in a 3D biomimetic model and spheroid formation in stiffer environments. High LH1 expression correlated with poor prognosis of both HCC and PDAC patients, while it also promoted in vivo metastasis. Mechanistically, LH1 bound and stabilized Septin2 (SEPT2) to enhance actin polymerization, depending on the hydroxylase domain. Finally, the subpopulation with high expression of both LH1 and SEPT2 had the poorest prognosis. CONCLUSIONS: LH1 promotes the confined migration and metastasis of cancer cells by stabilizing SEPT2 and thus facilitating actin polymerization.

USP9X-mediated NRP1 deubiquitination promotes liver fibrosis by activating hepatic stellate cells.

Liver fibrosis is a complex fibrotic process that develops early in the course of cirrhosis and is caused by chronic liver damage. The activation of hepatic stellate cells is primarily responsible for the fibrosis process. Studies show that NRP1 influences HSC motility and migration. However, whether NRP1 regulates HSC activation remains unknown. C57BL/6 male mice (6-8 weeks old) were intraperitoneally injected with 10% CCl4 in olive oil (5 µl/g body weight) every three days for four weeks to create an animal model of liver fibrosis. Control mice received olive oil (5 µl/g body weight). Different assays such as immunohistochemistry, immunostaining, Western blotting, qRT-PCR, immunoprecipitation, immunoprecipitation, and GST pull-down assays, and in vivo and in vitro ubiquitination assays were conducted. We found that NRP1 expression was significantly elevated both in mouse and human fibrotic livers, mainly in activated HSCs at the fibrotic foci. NRP1 promoted HSC activation via the cytokine TGF-ß1, VEGFA, and PDGF-BB. Moreover, USP9X was found to be a critical deubiquitinating enzyme for the stability and high activity of NRP1 and NRP1 deubiquitination mediated by USP9X enhanced HSC activation and liver fibrosis. NRP1 deubiquitination mediated by USP9X enhances HSC activation, implying that targeting NRP1 or USP9X potentiates novel options in the treatment of liver fibrosis.

P2Y1R Ligation Suppresses Th17 Cell Differentiation and Alleviates Colonic Inflammation in an AMPK-Dependent Manner.

P2Y1 receptor is a G-protein-coupled receptor that plays a critical role in the immune response of inflammatory bowel diseases. However, its regulatory effects on CD4+ T cell response have not been fully elucidated. The study aimed to characterize the role of P2Y1R in Th17 cell differentiation and colonic inflammation. Our results demonstrated that P2Y1R was significantly increased in the splenocytes of colitic mice, which was positively associated with the expression of RORγt and IL-17A. P2Y1R deficiency significantly ameliorated DSS-induced colitis and its Th17 responses. In parallel, P2Y1R deficiency greatly impaired the differentiation of Th17 cell, down-regulated the mRNA expression of IL-17A and RORγt, and protein expression of RORγt in vitro. More importantly, it was found that P2Y1R deficiency markedly increased AMPK phosphorylation of Th17 polarized CD4+ T cells, and antagonist of AMPK significantly reversed the inhibitory effect of P2Y1R deficiency on Th17 cell generation in vivo and in vitro. Overall, these findings demonstrated that P2Y1R deficiency could suppress Th17 cell differentiation in an AMPK-dependent manner to ameliorate colitis, and P2Y1R can act as an important regulator of Th17 cell differentiation to control colonic inflammation.

Rab31 promotes activation of hepatic stellate cells by accelerating TGF-ß receptor II complex endocytosis.

BACKGROUND & AIMS: Hepatic stellate cells activation is the key process of liver fibrosis, revealing the molecular mechanism of which is helpful to provide an effective target for inhibiting liver fibrosis. Rab31, a small GTPase, regulates the specificity of intracellular vesicular transport system, and is crucial for signal transduction. However, whether Rab31 is involved in hepatic stellate cells activation is unknown. METHODS & RESULTS: Analysis of the differences in gene expression between human healthy and fibrotic liver tissues by sequencing revealed that Rab31 was significantly upregulated in fibrotic tissues. Immunohistochemistry and immunofluorescence analysis confirmed that Rab31 positively correlated with hepatic fibrosis. Next, mouse primary hepatic stellate cells were prepared, and their continuous activation was accompanied by Rab31 expression increased. Interestingly, knockdown of Rab31 by lentivirus can significantly restrict those cell activation. Subsequently, the vary of signal transduction after Rab31 knockdown was detected, its presented that the TGF-ß/Smads signaling was obviously affected. Following experiments identified that Rab31 knockdown significantly inhibited the TGF-ß activation and led to the failure of hepatic stellate cells activation. Importantly, we revealed that Rab31 knockdown could inhibit TGF-ß receptor II complex endocytosis, a prerequisite for the activation of TGF-ß signaling. Finally, in a mouse CCl4 fibrosis model, we proved that Rab31 knockdown markedly inhibited hepatic fibrosis. CONCLUSIONS: Our study demonstrated that Rab31 could promote hepatic stellate cells activation by accelerating TGF-ß Receptor II complex endocytosis, suggesting that interfering with Rab31 could be an effectively strategy to inhibit hepatic fibrosis progression.

Synthesis, Characterization, DNA/HSA Interactions, and Anticancer Activity of Two Novel Copper(II) Complexes with 4-Chloro-3-Nitrobenzoic Acid Ligand.

The purpose of this study was to identify new metal-based anticancer drugs; to this end, we synthesized two new copper(II) complexes, namely [Cu(ncba)4(phen)] (1) and [Cu(ncba)4(bpy)] (2), comprised 4-chloro-3-nitrobenzoic acid as the main ligand. The single-crystal XRD approach was employed to determine the copper(II) complex structures. Binding between these complexes and calf thymus DNA (CT-DNA) and human serum albumin (HSA) was explored by electronic absorption, fluorescence spectroscopy, and viscometry. Both complexes intercalatively bound CT-DNA and statically and spontaneously quenched DNA/HSA fluorescence. A CCK-8 assay revealed that complex 1 and complex 2 had substantial antiproliferative influences against human cancer cell lines. Moreover, complex 1 had greater antitumor efficacy than the positive control cisplatin. Flow cytometry assessment of the cell cycle demonstrated that these complexes arrested the HepG2 cell cycle and caused the accumulation of G0/G1-phase cells. The mechanism of cell death was elucidated by flow cytometry-based apoptosis assays. Western blotting revealed that both copper(II) complexes induced apoptosis by regulating the expression of the Bcl-2(Bcl-2, B cell lymphoma 2) protein family.

A positive COX-2/IL-1ß loop promotes decidualization by upregulating CD82.

A successful pregnancy requires sufficient decidualization of endometrial stromal cells (ESCs). CD82, a metastasis suppressor, is a critical regulator for trophoblast invasion but the effect in decidualization was largely unknown. Here we reported that there was a high level of CD82 in DSC by the immunohistochemistry staining and flow cytometer analysis. Stimulation with prostaglandin E2 (PGE2) elevated the expression of CD82 in ESCs. In contrast, celecoxib, a selective COX-2 inhibitor, significantly downregulated the expression of CD82 in decidual stromal cells (DSCs). Bioinformatics analysis and further research showed that recombinant human interleukin (IL)-1ß protein (rhIL-1ß) upregulated CD82 in ESCs. Of note, blocking IL-1ß signaling with anti-human IL-1ß neutralizing antibody could reverse the stimulatory effect of PGE2 on CD82 in ESCs. Silencing CD82 resulted in the decease of the decidualization markers PRL and IGFBP1 mRNA levels in DSCs. More importantly, we observed rhIL-1ß also upregulated the expression of COX-2, and the upregulation of PRL and IGFBP1 induced by rhIL-1ß could be abolished by celecoxib in ESCs or CD82 deficiency in DSCs. This study suggests that CD82 should be a novel promotor for decidualization under a positive regulation of the COX-2/PGE2/IL-1ß positive feedback loop.

Epigenetic silencing of GCH1promotes hepatocellular carcinoma growth by activating superoxide anion-mediated ASK1/p38 signaling via inhibiting tetrahydrobiopterin de novo biosynthesis.

Metabolic reprogramming is a hallmark of cancer, including hepatocellular carcinoma (HCC). However, its role in HCC remains to be elucidated. Herein, we identified GTP cyclohydrolase 1 (GCH1), the first rate-limiting enzyme in tetrahydrobiopterin (BH4) de novo biosynthesis, as a novel metabolic regulator of HCC. GCH1 was frequently down-regulated in HCC tissues and cell lines by promoter methylation. Low GCH1 expression was associated with larger tumor size, increased tumor number, and worse prognosis in two independent cohorts of HCC patients. Functionally, GCH1 silencing promoted HCC growth in vitro and in vivo, while GCH1 overexpression exerted an opposite effect. The metabolite BH4 inhibited HCC growth in vitro and in vivo. GCH1 silencing exerted its growth-promoting effect through directly inhibiting BH4 de novo biosynthesis. Mechanistically, GCH1 silencing activated ASK1/p38 signaling; pharmacological or genetic inhibition of ASK1 or p38 abolished GCH1 silencing-induced growth-promoting effect. Further mechanistic studies found that GCH1 silencing-induced BH4 reduction resulted in an increase of intracellular superoxide anion levels in a dose-dependent manner, which mediated the activation of ASK1/p38 signaling. Collectively, our study reveals that epigenetic silencing of GCH1 promotes HCC growth by activating superoxide anion-mediated ASK1/p38 signaling via inhibiting BH4 de novo biosynthesis, suggesting that targeting GCH1/BH4 pathway may be a promising therapeutic strategy to combat HCC.

Ubiquitin-specific protease 2a promotes hepatocellular carcinoma progression via deubiquitination and stabilization of RAB1A.

PURPOSE: Deubiquitination, the inverse process of ubiquitination, is catalyzed by deubiquitinases (DUBs) that remove ubiquitin from target proteins and subsequently prevent their degradation by proteasomes. Previously, deubiquitination has been found to be involved in hepatocellular carcinoma (HCC) progression. As yet, however, little is known about the exact role of deubiquitination in the development and/or progression of this type of cancer. METHODS: HCC tissues and tissue microarrays were used to detect expression of the DUB ubiquitin-specific protease 2a (USP2a). The critical role of USP2a in HCC development and progression was assessed in both in vitro cell and in vivo animal models. LC-MS/MS analyses were performed to identify potential targets of USP2a in HCC cells, after which regulation of target protein stability and ubiquitin status by USP2a were investigated. RESULTS: We found that USP2a was significantly upregulated in HCC tissues, and that a high expression was positively associated with a poor prognosis. Subsequently, we found that USP2a silencing resulted in inhibition of HCC cell proliferation, migration and invasion, whereas exogenous USP2a overexpression resulted in the opposite effects, both in vitro and in vivo. Mechanistically, LC-MS/MS analysis revealed that RAB1A, a key regulator of the ER and Golgi vesicular transport system, serves as a potential target of USP2a in HCC cells. In addition, we found that USP2a can deubiquitinate and stabilize RAB1A and prevent its degradation, and that this process is required for inducing HCC progression by USP2a. CONCLUSIONS: Our data indicate that USP2a can promote HCC progression via deubiquitination and stabilization of RAB1A. This observation indicates that DUB targeting may serve as a novel approach to improve the treatment of HCC.

Correction to: AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.

[This corrects the article DOI: 10.1038/boneres.2017.44.].

Cholesterol impairs hepatocyte lysosomal function causing M1 polarization of macrophages via exosomal miR-122-5p.

Nonalcoholic steatohepatitis (NASH) is a major threat to health worldwide. Lipotoxicity and macrophage-mediated inflammation play key roles in the pathogenesis of NASH. In this study, we found that individuals with higher serum LDL-C levels have a higher prevalence of nonalcoholic fatty liver disease (NAFLD) and elevated levels of glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and alkaline phosphatase. A logistic regression analysis revealed that serum LDL-C level is an independent risk factor for the prevalence and prognosis of NAFLD. In vitro, we used ox-LDL and MßCD-cholesterol to treat Huh7 cells and found that cholesterol loading reduced lysosomal quantity and impaired lysosomal acidification, reducing the number of multivesicular bodies (MVBs) colocalizing with lysosomes. The bafilomycin A1 inhibition of lysosomal function also inhibited lysosomal MVBs degradation, promoting the release of exosomes from the Huh7 cells. Next, we found that cholesterol loading promoted exosome release from the Huh7 cells. The exosomes from the cholesterol-loaded cells increased the ratio of the THP-1 cells positive for the M1 marker (iNOS-1) without affecting the ratio of the cells positive for the M2 marker (CD206). Moreover, an elevated level of miR-122-5p was observed in exosomes derived from the Huh7 cells loaded with cholesterol. While the miR-122-5p mimics promoted THP-1 M1 polarization, downregulating miR-122-5p in the Huh7 cells inhibited the exosome-induced activation of macrophages and macrophage-related inflammation. These findings suggest that cholesterol plays an important role in the development and progression of NASH. Cholesterol-induced lysosomal dysfunction increases exosome release from hepatocytes, resulting in M1 polarization and macrophage-induced inflammation in a miR-122-5p-dependent manner.

Cholesterol attenuated the progression of DEN-induced hepatocellular carcinoma via inhibiting SCAP mediated fatty acid de novo synthesis.

Worldwide, hepatocellular carcinoma (HCC) remains a top instigator of cancer mortality. Previous clinical studies have revealed that low serum cholesterol predicts a poor outcome in HCC patients, but the potential role of cholesterol in the progression of HCC remains controversial. In the present study,we tested the influence of cholesterol on the progression of DEN-induced HCC by feeding mice with a high cholesterol diet (HCD) and by depriving cholesterol with atorvastatin, a widely used inhibitor of the mevalonate pathway. We found that HCD induced more and larger liver tumors and an increased occurrence of lung metastasis in DEN-injected mice. These effects could be prevented by cholesterol deprivation with atorvastatin. In vitro, cholesterol loading repressed the proliferation, migration, and the invasion of SK hep1 cells, which was additionally prevented by cholesterol deprivation. Both in vivo and in vitro, cholesterol loading decreased the expression of Sterol regulatory element-binding protein cleavage-activating protein (SCAP), the translocation of sterol regulatory element-binding protein1 (SREBP1) to the nucleolus, and the genetic expression of FAS and ACC-1. Over-expression of SCAP in cholesterol-loaded SK hep1 cells promoted the nuclear translocation of SREBP1 and the expression of FAS and ACC-1, which promoted the proliferation, migration, and the invasion of SK hep1 cells. Knockdown of SCAP also restrained the cholesterol deletion-mediated up-regulation of fatty acid de novo synthesis in SK hep1 cells, inhibiting the atorvastatin-mediated proliferation, migration, and invasion of SK hep1 cells. In conclusion, cholesterol inhibited the progression of HCC through restraining SCAP-mediated fatty acid de novo synthesis.

Ubiquitin-specific protease 4 promotes metastasis of hepatocellular carcinoma by increasing TGF-ß signaling-induced epithelial-mesenchymal transition.

Invasion and metastasis are the main cause of recurrence and death in advanced hepatocellular carcinoma (HCC). Revealing the mechanisms of HCC metastasis is important for developing new therapeutic approaches and reducing patient mortality. Ubiquitin specific protease 4 (USP4), is involved in tumorigenesis by deubiquitinating some important oncogenic proteins and impacting their degradation. In the present study, we found that USP4 was significantly upregulated in HCC tumor tissues and the high expression of USP4 was associated with distant metastasis and poor survival in patients. Using gene interference, we demonstrated that USP4 knockdown significantly inhibited HCC cell migration and invasion in vitro, and USP4 overexpression had the opposite results. In vivo, we also found that USP4 knockdown obviously blocked HCC cell metastasis. Mechanistically, we revealed that USP4 interacted directly with and deubiquitinated TGF-ß receptor type I (TGFR-1) to activate the TGF-ß signaling pathway, and subsequently induced the Epithelial-Mesenchymal Transition (EMT) in HCC cells. Taken together, our results elucidate that USP4 is highly expressed in HCC and promotes the tumor invasion and metastasis, the underlying mechanism is that USP4 directly interacts with and deubiquitinates TGFR-1 to increase TGF-ß signaling-Induced EMT. These results could provide a new therapeutic target for the treatment of HCC.

Effects of L-borneol on chloride channel and cell volume in human umbilical vein endothelial cells / 中国药理学通报

Aim To study the effects of L-borneol on the chloride channel and cell volume of human umbili-cal vein endothelial cells (HUVECs). Methods Whole-cell patch-clamp technique was used to record chloride currents. The expression of ClC-3 protein was down-regulated by siRNA interference technique. The cell volume was measured by dynamic image analysis. Results 20 nmol·L-1L-borneol significantly activa-ted chloride current in HUVEC (79.59 ± 4.90) pA/pF, which could be inhibited by chloride channel blockers,NPPB and DIDS. The outward current inhib-itory rate of NPPB was (95.57 ± 2.57)%, while that of DIDS was (97.28 ± 6.36)%. The chloride current activated by L-borneol significantly decreased after the silence of ClC-3 (27.03 ± 3.89) pA/pF. Cell volume was markedly reduced by L-borneol (14.38 ± 1.58)%,which was inhibited after NPPB appliance. Conclusion L-borneol can activate ClC-3 chloride channel in HUVECs, which induces Cl- outflow then cell volume decrease.

Modulating Effects and Mechanisms of p53-miR-34a-SIRT1 Feedback Loop on Reproductive Senescence of Vascular Endothelial Progenitor Cells / 中国循环杂志

Objectives: To explore the modulating effects and related mechanisms of p53-miR-34a-SIRT1 feedback loop in the process of replication senescence of vascular endothelial progenitor cells (EPC). Methods: EPC derived from umbilical cord blood were cultured and identified. Differences on senescence, cell apoptosis, cell cycle and blood tube formation were observed in EPC of 3rdand 6thgeneration. Protein expression of p53, Acetyl-p53, and SIRT1 was also detected by Western blotting in EPC of 3rdand 6thgeneration. The miR-34a inhibitor lentiviral vector was constructed and used to identify whether miR-34a inhibitor can protect 6thgeneration EPC from apoptosis. Results: EPC derived from umbilical cord blood were successfully cultured. The cells senescence rate and apoptosis rate of the 6thgeneration EPC were significantly higher than those of the 3rdgeneration EPC. The cell cycle of 6thgeneration EPC was mainly arrested at G0/G1 phase. The protein expression level of p53 was significantly higher, while the protein expression of acetyl-p53 and SIRT1 was significantly lower in the 6thgeneration EPC than in the 3rdgeneration EPC, all P<0.05. The senescence was significantly attenuated, and late apoptotic cells were significantly reduced, while angiogenesis ability was significantly enhanced in the 6thgeneration EPC transfected with lentiviral vector carrying miR-34a inhibitor. Conclusions: p53-miR-34a-SIRT1 is an important feedback mechanism in the process of EPC replication senescence. The miR-34a inhibitor may be the potential target of delaying EPC senescence.

Effects of ClC-3 over-expression on structure and function of thyroid in mice / 中国病理生理杂志

AIM:To study the effect of ClC-3 gene over-expression on thyroid structure and function in mice. METHODS:Three-months-old FVB mice were used to study the difference of thyroid structure and function between wild-type(WT)mouse and ClC-3 transgene mice.The expression and distribution of ClC-3 in the thyroid of mice were deter-mined by the methods of qPCR,Western blot and immunofluorescence.Behavioral monitoring was performed on the daily activities of mice.Serum concentrations of total triiodothyronine(TT3), total thyroxine(TT4)and thyrotropin(TSH) were measured by ELISA.RESULTS:Compared with the WT group,the expression of ClC-3 in the thyroid of ClC-3 trans-gene group was significantly increased(P<0.05).The thyroid gland showed obvious hyperplasia and the folliculi glandu-lae thyreoideae was significantly bigger in ClC-3 transgene mice(P<0.05).The weight loss was increased in ClC-3 trans-gene mice(P<0.05).The expression of TT3 and TT4 were significantly higher than that of WT group(P<0.05),but the change of TSH was not obvious.CONCLUSION:ClC-3 over-expression results in thyroid hyperplasia and thyroid hor-mone secretion.This study suggests that ClC-3 is likely to be involved in the synthesis of thyroid hormones.

AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.

AFF1 and AFF4 belong to the AFF (AF4/FMR2) family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b (P-TEFb) and ELL1/2, in super elongation complexes (SECs). Both AFF1 and AFF4 regulate gene transcription through elongation and chromatin remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells (MSCs) is unknown. In this study, we show that small interfering RNA (siRNA)-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase (ALP) activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFF1 regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFF1-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.