Dual role of RACK1 in airway epithelial mesenchymal transition and apoptosis.

Airway epithelial apoptosis and epithelial mesenchymal transition (EMT) are two crucial components of asthma pathogenesis, concomitantly mediated by TGF-ß1. RACK1 is the downstream target gene of TGF-ß1 shown to enhancement in asthma mice in our previous study. Balb/c mice were sensitized twice and challenged with OVA every day for 7 days. Transformed human bronchial epithelial cells, BEAS-2B cells were cultured and exposed to recombinant soluble human TGF-ß1 to induced apoptosis (30 ng/mL, 72 hours) and EMT (10 ng/mL, 48 hours) in vitro, respectively. siRNA and pharmacological inhibitors were used to evaluate the regulation of RACK1 protein in apoptosis and EMT. Western blotting analysis and immunostaining were used to detect the protein expressions in vivo and in vitro. Our data showed that RACK1 protein levels were significantly increased in OVA-challenged mice, as well as TGF-ß1-induced apoptosis and EMT of BEAS-2B cells. Knockdown of RACK1 (siRACK1) significantly inhibited apoptosis and decreased TGF-ß1 up-regulated EMT related protein levels (N-cadherin and Snail) in vitro via suppression of JNK and Smad3 activation. Moreover, siSmad3 or siJNK impaired TGF-ß1-induced N-cadherin and Snail up-regulation in vitro. Importantly, JNK gene silencing (siERK) also impaired the regulatory effect of TGF-ß1 on Smad3 activation. Our present data demonstrate that RACK1 is a concomitant regulator of TGF-ß1 induces airway apoptosis and EMT via JNK/Smad/Snail signalling axis. Our findings may provide a new insight into understanding the regulation mechanism of RACK1 in asthma pathogenesis.

Compound danshen tablet ameliorated aß25-35-induced spatial memory impairment in mice via rescuing imbalance between cytokines and neurotrophins.

BACKGROUND: Compound Danshen Tablet (CDT), a Traditional Chinese Medicine, has recently been reported to improve spatial cognition in a rat model of Alzheimer's disease. However, in vivo neuroprotective mechanism of the CDT in models of spatial memory impairment is not yet evaluated. The present study is aimed to elucidate the cellular mechanism of CDT on Aß25-35-induced cognitive impairment in mice. METHODS: Mice were randomly divided into 5 groups: the control group (sham operated), the Aß25-35 treated group, the positive drug group, and large and small dosage of the CDT groups, respectively. CDT was administered at a dose of 0.81 g/kg and 0.405 g/kg for 3 weeks. The mice in the positive drug group were treated with 0.4 mg/kg of Huperzine A, whereas the mice of the control and Aß25-35 treated groups were administrated orally with equivalent saline. After 7 days of preventive treatment, mice were subjected to lateral ventricle injection of Aß25-35 to establish the mice model of Alzheimer's disease. Spatial memory impairment was evaluated by Morris water maze test. Choline acetyltransferase (ChAT) contents in hippocampus and cortex were quantified by ELISA. The levels of cytokines, receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in hippocampus were measured by RT-PCR and ELISA. RESULTS: The results showed that Aß25-35 caused spatial memory impairment as demonstrated by performance in the Morris water maze test. CDT was able to confer a significant improvement in spatial memory, and protect mice from Aß25-35-induced neurotoxicity. Additionally, CDT also inhibited the increase of TNF-α and IL-6 level, and increased the expression of choline acetyltransferase (ChAT), receptor of activated protein kinase C1 (RACK1) and brain-derived neurotrophic factor (BDNF) in brain as compared to model mice. CONCLUSION: These findings strongly implicate that CDT may be a useful treatment against learning and memory deficits in mice by rescuing imbalance between cytokines and neurotrophins.

MiR-451a suppressing BAP31 can inhibit proliferation and increase apoptosis through inducing ER stress in colorectal cancer.

The global morbidity and mortality of colorectal cancer (CRC) are ranked the third among gastrointestinal tumors in the world. MiR-451a is associated with several types of cancer, including CRC. However, the roles and mechanisms of miR-451a in CRC have not been elucidated. BAP31 is a predicted target gene of miR-451a in our suppression subtractive hybridization library. Its relationship with miR-451a and function in CRC are unclear. We hypothesized that miR-451a could induce apoptosis through suppressing BAP31 in CRC. Immunohistochemistry and real-time PCR were used to measure BAP31 expressions in CRC tissues and pericarcinous tissues from 57 CRC patients and CRC cell lines. Dual-luciferase reporter assay was used to detect the binding of miR-451a to BAP31. The expression of BAP31 protein in CRC tissues was significantly higher than that in pericarcinous tissues, which was correlated with distant metastasis and advanced clinical stages of CRC patients. The expression of BAP31 was higher in HCT116, HT29, SW620, and DLD cells than that in the normal colonic epithelial cell line NCM460. The expression of BAP31 was absolutely down-regulated when over-expressing miR-451a in HCT116 and SW620 cells compared with control cells. Mir-451a inhibited the expression of BAP31 by binding to its 5'-UTR. Over-expressing miR-451a or silencing BAP31 suppressed the proliferation and apoptosis of CRC cells by increasing the expressions of endoplasmic reticulum stress (ERS)-associated proteins, including GRP78/BIP, BAX, and PERK/elF2α/ATF4/CHOP, which resulted in increased ERS, cytoplasmic calcium ion flowing, and apoptosis of CRC cells. These changes resulting from over-expressing miR-451a were reversed by over-expressing BAP31 with mutated miR-451a-binding sites. Over-expressing miR-451a or silencing BAP31 inhibited tumor growth by inducing ERS. The present study demonstrated that miR-451a can inhibit proliferation and increase apoptosis through inducing ERS by binding to the 5'-UTR of BAP31 in CRC.

NUDCD1 promotes metastasis through inducing EMT and inhibiting apoptosis in colorectal cancer.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the third leading cause of cancer death in both men and women. NudC domain containing 1 (NUDCD1) was identified as an oncoprotein which was activated or over-expressed in various human cancers. We aimed to investigate the effects and mechanisms of NUDCD1 in human CRC. The expression of NUDCD1 in CRC and pericarcinous tissues from 70 CRC patients were determined by real-time PCR, western blotting, and immunohistochemistry. The correlation between the expression of NUDCD1 and clinical characteristics was analyzed. The expression of NUDCD1 in five CRC cell lines and normal colon mucosal epithelial cell line was measured by real-time PCR. Then we knock down NUDCD1 in HCT116 and HT 29 cells. The cell viability assay, scratch assay, migration and invasion assay and flow cytometry were used to analyze NUDCD1's effects on the proliferation, migration, invasion, cell cycle and apoptosis of CRC cells. NUDCD1's effects on CRC xenografts of nude mice was also determined. Results showed that the expression of NUDCD1 was much higher in CRC tissues than that in pericarcinous tissues. Over-expression of NUDCD1 in human CRC tissues was significantly associated with lymph node metastasis, distant metastasis, and advanced stages. The expression of NUDCD1 was higher in all of the CRC cell lines than that in normal colon epithelial mucosal cells. To knockdown NUDCD1 resulted in significant decreases in cell viability and proliferation, decreased protein expression of N-cadherin and increased protein expression of E-cadherin which were biomarkers of EMT, arrested the cell cycle and increased apoptosis via down-regulated cyclin D1, Bcl2, and up-regulated cleaved-caspase3. Furthermore, to knockdown NUDCD1 inactivated IGF1R-ERK1/2 signaling pathway in vitro and in vivo, and suppressed the xenografts of CRC. In conclusion, NUDCD1 promotes the carcinogenesis and metastasis of CRC through inducing EMT and inhibiting apoptosis, which suggests NUDCD1 be a potential biomarker for CRC.

Protective effects of losartan in mice with chronic viral myocarditis induced by coxsackievirus B3.

AIM: To investigate whether losartan has protective effects in mice with chronic viral myocarditis induced by coxsackievirus B3 (CVB3). MAIN METHODS: Thirty two male Balb/c mice were intraperitoneally injected with CVB3 (10×TCID50) to induce chronic viral myocarditis (CVM). Losartan at 12.5mg/kg (n=16) or normal saline (n=16) were orally administered daily for 28 days to these mice. Uninfected mice (n=6) were used as controls. On day 29, all mice underwent anesthesia and echocardiography prior to sacrifice. Serum IL-17, IL-4, IFN-γ and TNF-α levels were measured by enzyme-linked immunosorbent assay, and cardiac tissues were histologically examined after hematoxylin & eosin staining. In addition, the effect of losartan on the virus titers in primary cultured neonatal rat cardiomyocytes infected with CVB3 was measured on Hep-2 cells at 72 h post infection. KEY FINDINGS: Mice infected with CBV3 had significantly increased mortality, heart/body weight ratios, necrosis and inflammatory scores and decreased cardiac ejection fractions, compared with the controls (all P<0.05). Losartan significantly decreased mortality from 40.0% to 12.5%, heart/body weight ratios from 7.08 ± 2.17 to 4.15 ± 0.99, and necrosis and inflammatory scores from 3.33 ± 0.50 to 2.50 ± 0.65 (all P<0.05), and increased ejection fractions from 55.80 ± 9.25 to 72.31 ± 12.15 (P<0.05). Losartan significantly enhanced IL-4, and decreased IFN-γ, TNF-α and IL-17 (all P<0.05). In the in vitro experiment, losartan had no influence on virus titers. SIGNIFICANCE: Losartan protects mice against CVB3-induced CVM, most likely through upregulating Th2 responses, and down-regulating Th1 and Th17 responses.