Estrogen protects against acidosis-mediated articular chondrocyte injury by promoting ASIC1a protein degradation.

Epidemiological data suggest that the incidence of rheumatoid arthritis (RA) increases in postmenopausal women, which may be related to estrogen deficiency. Tissue acidosis is a common symptom of RA. Acid-sensitive ion channel 1a (ASIC1a), a member of the extracellular H+-activated cation channel family, could be activated by changes in extracellular pH and plays a crucial role in the pathogenesis of RA. As the only cellular component in cartilage tissue, chondrocytes play an extremely important role in maintaining cartilage tissue homeostasis. The aim of this study was to investigate whether estrogen could protect acid-stimulated chondrocytes by regulating the expression of ASIC1a and explore the possible mechanism. The results showed that estrogen could protect against acid-induced chondrocyte injury by reducing ASIC1a protein expression. Moreover, lysosome inhibitor chloroquine (CQ) and autophagy inhibitor 3-methyladeniine (3-MA) could reverse the reduction of ASIC1a protein caused by estrogen, indicating that autophagy-lysosome pathway contributes to estrogen-induced degradation of ASIC1a protein. Furthermore, the down-regulation of ASIC1a expression by estrogen was attenuated by MPP, a specific inhibitor of estrogen-related receptor-alpha (Esrra), indicating that Esrra is involved in the process of estrogen regulating the expression of ASIC1a. Additionally, adenosine 5'-monophosphate (AMP)-activated protein kinase/unc-51-like kinase 1 (AMPK-ULK1) signaling pathway was activated by estrogen treatment, which was abrogated by Esrra-silencing, and AMPK-specific inhibitor Compound C pretreatment could reduce estrogen-induced downregulation of ASIC1a protein. Taken together, these results indicate that estrogen could promote autophagy-lysosome pathway-dependent ASIC1a protein degradation and protect against acidosis-induced cytotoxicity, the mechanisms of which might relate to Esrra-AMPK-ULK1 signaling pathway.

17ß-estradiol attenuates rat articular chondrocyte injury by targeting ASIC1a-mediated apoptosis.

Epidemiological evidence suggests that the etiology and pathogenesis of rheumatoid arthritis (RA) are closely associated with estrogen metabolism and deficiency. Estrogen protects against articular damage. Estradiol replacement therapy ameliorates local inflammation and knee joint swelling in ovariectomized models of RA. The mechanistic basis for the protective role of 17ß-estradiol (17ß-E2) is poorly understood. Acid-sensing ion channel 1a (ASIC1a), a sodium-permeable channel, plays a pivotal role in acid-induced articular chondrocyte injury. The aims of this study were to evaluate the role of 17ß-E2 in acid-induced chondrocyte injury and to determine the effect of 17ß-E2 on the level and activity of ASIC1a protein. Results showed that pretreatment with 17ß-E2 attenuated acid-induced damage, suppressed apoptosis, and restored mitochondrial function. Further, 17ß-E2 was shown to reduce protein levels of ASIC1a through the ERα receptor, to protect chondrocytes from acid-induced apoptosis, and to induce ASIC1a protein degradation through the autophagy-lysosomal pathway. Taken together, these results show that the use of 17ß-E2 may be a novel strategy for the treatment of RA by reducing cartilage destruction through down-regulation of ASIC1a protein levels.

4-Amino-2-trifluoromethyl-phenyl retinate induced differentiation of human myelodysplastic syndromes SKM-1 cell lines by up-regulating DDX23.

Myelodysplastic syndrome (MDS) is a heterogeneously cloned hematopoietic stem cell malignancy with a high risk of developing acute myeloid leukemia (AML). 4-amino-2-trifluoromethyl-phenyl resinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative designed in our group, was proved to be a tumor inhibitor in diverse types of cancer cells in vitro. However, little has been known about the effects of ATPR on MDS. To analyze if and to what extent it's anti-tumor activity on MDS, we performed CCK-8, Flow Cytometry, Wright-Giemsa staining, qRT-PCR, and Western blot to analyze the SKM-1 cells state after ATPR treatment in multiplex detection angles. As expected, our results proved that ATPR could effectively induce cell differentiation and reduce cell proliferation of SKM-1 cell lines. Subsequently, to further analyze the potential mechanisms, we applied Label-free proteomic techniques to discover relevant protein that may be involved. Most notably, a series of factors related to RNA behavioral regulation were changed. Among them, we demonstrated that DEAD-box RNA helicase DDX23 was abnormally ablated in MDS patients and could be restored after ATPR treatment in vitro. Besides, our results suggested that ATPR-induced SKM-1 cell maturation was counteracted when knockdown DDX23, underscoring that DDX23 might be involved. In conclusion, we confirmed that ATPR could induce SKM-1 cells differentiation and its positive influence of DDX23 may provide a new idea to relieve MDS.

A novel all-trans retinoic acid derivative inhibits proliferation and induces apoptosis of myelodysplastic syndromes cell line SKM-1 cells via up-regulating p53.

Myelodysplastic syndromes (MDS) are a varied set of hematologic neoplasms and a high risk of progression to acute myeloid leukemia (AML). 4-Amino-2-trifluoromethyl-phenyl retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative, play an important role in various types of cancer cells as a tumor inhibitor. However, little is known concerning its antitumor effect on MDS. The cell viability and the percentage of apoptotic cells were used to measure MTT, Flow Cytometry and Hoechst 33342/PI staining. In addition, real-time quantitative RT-PCR (qRT-PCR) and western blotting were used to analyzed the expression of p53, as well as the levels of BNIP3, apoptosis proteins of Caspase-3, BAX and BCL-2. After SKM-1 cells were incubated with DAC, ATRA and ATPR, the viability of the SKM-1 cells was inhibited in a dose- and time-dependent manner. Both Hoechst staining and flow cytometry showed the apoptosis of SKM-1 cells was increased. Moreover, SKM-1 cells treated with ATPR unveiled elevated mRNA and protein levels of p53, BNIP3, BAX and Caspase-3 expression and decreased BCL-2 expression. However, silencing p53 suppressed the pro-apoptosis function of ATPR. Consequently, these data provide the first evidence for ATPR increased apoptosis in SKM-1 cells by p53 that is mutually dependent on and obligatorily linked to BNIP3 gene activation.

Chronic inflammatory status in patients with coronary artery ectasia.

BACKGROUND: Coronary artery ectasia (CAE) is well-recognized, angiographic finding of abnormal coronary dilatation. The role of inflammation in atherosclerosis is increasingly well known. However, the association between inflammation and CAE has been controversial. METHOD: Fifty-five patients with CAE and non-obstructive coronary artery disease (CAD), 38 with obstructive CAD, and 33 angiographically normal coronary controls were enrolled in the study. The peripheral blood was taken, and white blood cell count (WBCC) as well as other leukocyte subtypes including neutrophils, lymphocytes, and monocyte cell count (MCC) were measured. The plasma levels of C-reactive protein (CRP) and interleukin-6 (IL-6) were determined by ELISA. RESULTS: The higher number of WBCC, neutrophil and MCC were found in patients with CAE compared with obstructive CAD patients as well as normal controls (p<0.01, respectively). Moreover, levels of plasma CRP and IL-6 were also significantly higher in patients with CAE than that in patients with obstructive CAD, and subjects without coronary artery disease (p<0.001, respectively). Univariate analysis showed that the sex, current smoking, numbers of WBCC, neutrophil, MCC, levels of CRP and IL-6 were related with CAE, while MCC was independently linked with a diagnosis of CAE. CRP was the independent variable most strongly associated with CAE by multivariate analysis. CONCLUSIONS: Taken together, this study confirmed and expanded previous limited findings that a more significant chronic inflammation might be linked with the pathogenesis of CAE that was associated with not only inflammatory markers but also inflammatory cells in patients with CAE.

Increased peripheral circulating inflammatory cells and plasma inflammatory markers in patients with variant angina.

BACKGROUND: Emerging data suggest that inflammation may play an important role in the pathogenesis of coronary artery disease. However, the relation of inflammatory status to coronary vasospasm has been less investigated in patients with variant angina (VA). PURPOSE: The aim of this study, therefore, was to determine peripheral circulating white blood cells as well as monocyte cells and plasma C-reactive protein (CRP) and interleukin-6 (IL-6) levels in patients with VA, and to compare patients with VA, stable coronary artery disease, and controls with angiographically normal coronary arteries. METHOD: Thirty-three consecutive patients with documented VA, 26 with stable coronary artery disease, and 22 normal controls (with angiographically normal coronary arteries) were involved in this study. The peripheral blood was taken, and white blood cells and monocyte cells were counted. The plasma concentrations of CRP and IL-6 were also evaluated by enzyme-linked immunosorbent assay (ELISA). RESULTS: The data showed that white blood cell counts and monocyte cell counts were significantly higher in patients of the VA group than in the other two groups (white blood cell counts: 7340+/-1893/mm vs. 6187+/-1748/mm vs. 5244+/-1532/mm, P<0.05, respectively; monocyte cell counts: 510+/-213/mm vs. 425+/-209/mm vs. 383+/-192/mm, P<0.05, respectively). Similarly, levels of plasma CRP and IL-6 were also significantly higher in patients of the VA group than in patients with stable coronary artery disease (CRP: 0.42+/-0.21 mg/l vs. 0.27+/-0.14 mg/l; IL-6: 10.4+/-1.0 pg/dl vs. 6.2+/-0.7 pg/dl, P<0.01, respectively), and patients with normal controls (CRP: 0.42+/-0.21 mg/l vs. 0.17+/-0.10 mg/l; IL-6: 10.4+/-1.0 pd/dl vs. 3.0+/-0.7 pg/dl, P<0.01, respectively). The multivariate analysis showed that CRP was the independent variable most strongly associated with VA. CONCLUSION: Taken together, these findings suggested that more chronic, severe inflammation might be involved in the pathogenesis of VA, manifested by increased counts of circulating inflammatory cells and elevated plasma levels of CRP and IL-6.