X. Zhang

BACKGROUND: Transforming growth factor (TGF)-β1 produced in airway epithelia has been suggested as a contributor to the airway remodeling observed in asthma patients. The protein tyrosine phosphatase SHP2 is a demonstrable modulator of TGF-β1 production and thus a potential regulator of airway remodeling. OBJECTIVES: To define the signal event by which SHP2 regulates asthmatic responses in airway epithelial cells by using a mouse model of experimental OVA-induced airway remodeling. METHODS: The airways of Shp2(flox/flox) mice were infected with recombinant adenovirus vectors expressing a Cre recombinase-green fluorescence protein (GFP) fusion protein as part of allergen provocation studies using mice sensitized with ovalbumin (OVA) and repeatedly challenged with OVA. Several endpoint pathologies were assessed, including airway hyper-responsiveness (AHR), lung inflammatory score, peribronchial collagen deposition, and α-smooth muscle actin (SMA) hyperplasia. In vitro studies using airway epithelial cells (BEAS-2B) were used to investigate the role of SHP2 in the regulation of pulmonary remodeling events, including the expression of collagen, α-SMA, and TGF-β1. RESULTS: Chronic OVA challenges in wild-type mice resulted in airway remodeling and lung dysfunction (e.g., increased inflammatory scores, collagen deposition (fibrosis), smooth muscle hyperplasia, and a significant increase in AHR). These endpoint pathology metrics were each significantly attenuated by conditional shp2 gene knockdown in airway epithelia. In vitro studies using BEAS-2B cells also demonstrated that the level of TGF-β1 production by these cells correlated with the extent of shp2 gene expression. CONCLUSIONS: SHP2 activities in airway epithelial cells appear to modulate TGF-β1 production and, in turn, regulate allergic airway remodeling following allergen provocation. CLINICAL IMPLICATIONS: Our findings identify SHP2 as a previously underappreciated contributor to the airway remodeling and lung dysfunction associated with allergen challenge. As such, SHP2 represents a potentially novel therapeutic target for the treatment of asthmatics. CAPSULE SUMMARY: Airway epithelial protein tyrosine phosphatase SHP2 appears to modulate TGF-β1 activities as part of one or more cellular pathways leading to regulating the airway remodeling and lung dysfunction occurring in mouse models of allergic respiratory inflammation.

Although mesenchymal stem cells (MSCs) are being tested for cardiac repair, the majority of transplanted cells undergo apoptosis in the ischaemic heart because of the effects of ischaemia/reperfusion, poor blood supply and other pro-apoptotic factors. Several experimental and clinical studies have suggested that cyclosporin A (CsA) treatment reduces apoptosis in human endothelial cells and neurocytes. However, the effect of CsA on the apoptosis in MSCs is still unclear. In this study, we investigated whether CsA could inhibit hypoxia/ reoxygenation (H/R)-induced apoptosis in MSCs. MSCs pre-incubated with or without CsA were subjected to 6 h of hypoxia followed by 12 h of reoxygenation. Our data showed that pre-incubation with 0.5-5 microM CsA dose-dependently protected the MSCs from H/R injury, as evidenced by decreased apoptosis and increased cell viability. CsA inhibited the H/R-induced translocation of cytochrome c, increased bcl-2 expression and restored mitochondrial membrane potential. CsA also increased the expression of p-BAD. We propose that preincubation MSCs with CsA inhibits MSC apoptosis through the mitochondrial and BAD pathway.

BACKGROUND: Successful clinical organ preservations are a prerequisite for organ transplantation. Diazoxide (DE), which shows a concentration-dependent selectivity for mitoK(+-)-ATP over plasma membrane K(+-)-ATP, displays protective effects during organ preservation. The current study investigated possible protective effects of DE on rat kidneys injured by hypothermic preservation. METHODS: Forty-eight Sprague-Dawley rats were randomly divided into six groups (n = 8): Celsior groups with kidneys preserved in Celsior solution for 0, 24 and 48 h and DE groups with kidneys preserved in DE (30 μM) plus Celsior solution for 0, 24 and 48 h. Superoxide dismutase (SOD) activity and the quantity of malonaldehyde (MDA) in the kidneys from each group were measured, and the levels of C/EBP homologous protein (CHOP) and caspase-12 were determined by immunohistochemistry staining and real-time reverse transcription quantitative polymerase chain reaction analysis. RESULTS: SOD activity was significantly higher and the quantity of MDA was significantly lower in the DE groups compared with the Celsior groups at both 24 and 48 h (P < 0.05). The expressions of CHOP and caspase-12 were also lower in DE groups at 24 and 48 h (P < 0.05). CONCLUSIONS: The present results demonstrate that DE exerts protective effects by attenuating oxidative stress injury through up-regulation of SOD activity and down-regulation of MDA quantity and by decreasing the cell apoptosis in kidneys by reducing the levels of CHOP and caspase-12 during hypothermic preservation.

BACKGROUND: RNA interference (RNAi) is a potential therapeutic tool in the treatment of various diseases, such as cancers and viral infections. Silencing of E7 genes is an effective method to suppress human papilloma virus (HPV)-related tumours. AIM: To determine the therapeutic potential of RNAi in controlling condyloma acuminatum (CA). METHODS: Small interfering (si)RNA duplexes or small-hairpin (sh)RNA-expressing plasmids targeting the E7 genes of HPV-6b or HPV-11were inoculated into cultured E7-expressing cells via cationic liposomes, or into E7 gene-expressing mouse tumour models intratumorally or intravenously. Experiments were performed in triplicate and E7 mRNA level was analysed by real-time PCR. RESULTS: The in vitro experiments found that both siRNAs and shRNA-expressing plasmids reduced the mRNA levels of HPV-6b or HPV-11 E7 to 20-40% at the optimum dosage of 25-50 nmol/L for siRNAs and 0.1-0.2 microg/mL for shRNA-expressing vectors. The optimum time for this to happen was 72 h. E7 mRNA expression in tumour models was reduced to 45-50% after three intratumural injections. Intratumoral injections of RNAi effectors induced greater inhibition than did intravenous injections. CONCLUSIONS: We conclude that HPV-6b/11 E7 gene expression can be specifically modulated by RNAi, which may provide a useful method in the management of CA.

The aim of this study is to investigate the functions and mechanisms of miR-608 in prostate cancer (PCa). CISH and qRT-PCR analysis demonstrated that miR-608 was low expressed in PCa tissues and cells, which was partly attributed to the methylation of CpG island adjacent to the transcription start site (TSS) of miR-608 gene. Intracellular miR-608 overexpression inhibited in vivo PCa tumor growth, and suppressed PCa cell proliferation, G2/M transition, and migration in vitro, which was independent of EMT-associated mechanisms. Then RAC2, a GTPase previously deemed hematopoiesis-specific but now discovered to exist and play important roles in PCa, was verified by western blot and dual-luciferase reporter assays to mediate the effects of miR-608 through RAC2/PAK4/LIMK1/cofilin pathway. MiR-608 also promoted the apoptosis of PCa cells through BCL2L1/caspase-3 pathway by targeting the 3'-UTR of BCL2L1. Moreover, PAK4, the downstream effector of RAC2, was found to be targeted by miR-608 at the mRNA coding sequence (CDS) instead of the canonical 3'-UTR. Knocking down RAC2, PAK4, or BCL2L1 with siRNAs reproduced the antiproliferative, mitosis-obstructive, antimigratory and proapoptotic effects of miR-608 in PCa cells, which could be attenuated by downregulating miR-608. In conclusion, miR-608 suppresses PCa progression, and its activation provides a new therapeutic option for PCa.