Sema3A ameliorates the pathological progression of osteoarthritis by modulating mitochondrial damage in chondrocytes.

Osteoarthritis (OA) is a major disease that causes disability in middle-aged and elderly people. A comprehensive understanding of its pathogenesis is of great significance in finding new clinical diagnosis and treatment schemes. The role of Semaphorin 3A (Sema3A) in OS has attracted attention recently, and the purpose of this study is to analyze the mechanisms underlying its impact on OS. First, a rat model of OS was established. Hematoxylin-eosin (HE) and TUNEL staining showed that the modeled rats presented typical pathological manifestations of OS, confirming the success of the modeling. Sema3A was significantly underexpressed in OS rats. Subsequently, Sema3A abnormal expression vectors were constructed to intervene in chondrocytes isolated from OS rats. It was found that the proliferation of chondrocytes was decreased, the apoptosis was increased, and the mitochondrial damage and autophagy were intensified after silencing Sema3A expression, while the above pathological processes were reversed when Sema3A expression was increased. In conclusion, Sema3A has an important influence on the pathological progression of OS, and molecular therapies targeting to increase Sema3A expression may become a new treatment for OS in the future.

Apolipoprotein E2 inhibits mitochondrial apoptosis in pancreatic cancer cells through ERK1/2/CREB/BCL-2 signaling.

BACKGROUND: Apolipoprotein E2 (ApoE2) is a pleiotropic protein that influences several aspects of cancer metabolism and development. Evading apoptosis is a vital factor for facilitating cancer cell growth. However, the role and mechanism of ApoE2 in regulating cell apoptosis of pancreatic cancer remain unclear. METHODS: In this study, we firstly detected the mRNA and protein expressions of ApoE2 in PANC-1 and Capan-2 cells by real-time polymerase chain reaction and Western blotting. We then performed TUNEL and flow cytometric analyses to explore the role of recombinant human ApoE2, pCMV6-ApoE2 and siApoE2 in the apoptosis of PANC-1 and Capan-2 cells. Furthermore, we investigated the molecular mechanism through which ApoE2 affected apoptosis in PANC-1 cells using immunofluorescence, immunoprecipitation, Western blotting and co-immunoprecipitation analysis. RESULTS: ApoE2 phosphorylated ERK1/2 and inhibited pancreatic cancer cell apoptosis. In addition, our data showed that ApoE2/ERK1/2 altered the expression and mitochondrial localization of BCL-2 via activating CREB. ApoE2/ERK1/2/CREB also increased the total BCL-2/BAX ratio, inhibited the opening of the mitochondrial permeability transition pore and the depolarization of mitochondrial transmembrane potential, blocked the leakage of cytochrome-c and the formation of the apoptosome, and consequently, suppressed mitochondrial apoptosis. CONCLUSIONS: ApoE2 regulates the mitochondrial localization and expression of BCL-2 through the activation of the ERK1/2/CREB signaling cascade to evade the mitochondrial apoptosis of pancreatic cancer cells. ApoE2 may be a distinct prognostic marker and a potential therapeutic target for pancreatic cancer.

Semaphorin3A regulates mitochondrial apoptosis in RAW264.7 cells in vitro.

Osteoclasts apoptosis plays vital roles in abnormal bone remodeling-associated diseases. It's reported that Semaphorin3A (Sema3A) may affect osteoarthritis progression through osteoclasts function, while the specific mechanism remains unclear. To determine the effect of Sema3A on osteoclasts, we detected the apoptosis of RAW264.7 cells treated with Sema3A and explored the potential pathways in vitro. Firstly, Cell Counting Kit-8 (CCK8) assay was performed to assess the proliferation to screen out the appropriate concentration of Sema3A. Then, apoptosis was evaluated after cells were incubated with Sema3A for 0, 2, 6, 12, 24 and 48 h, respectively, by Terminal Deoxynucleotidyl Transferase dUTP nick end labeling (TUNEL) staining and flow cytometry. Finally, phosphorylation of Nrf2 and CREB, mitochondrial apoptosis-related markers and JNK/AKT/ERK pathway activation were examined by qRT-PCR and Western blot. As a result, flow cytometry and TUNEL staining revealed that RAW264.7 cells apoptosis was promoted by Sema3A-treated. Meanwhile, Western blot showed that cleaved-caspase-3 and cleaved-caspase-9 were highly expressed in Sema3A-treated RAW264.7 cells, and the ERK/JNK/AKT pathways were significantly inhibited by Sema3A in RAW264.7 cells. In a word, we demonstrated that Sema3A induces apoptosis of RAW264.7 cells probably by promoting mitochondrial apoptosis, which may provide a potential target for therapeutic strategies.

Astrocytes directly clear myelin debris through endocytosis pathways and followed by excessive gliosis after spinal cord injury.

Persisted myelin debris inhibit axon regeneration and contribute to further tissue damage after spinal cord injury (SCI). The traditional view is that myelin debris is mainly cleared by microglia and macrophages, while astrocytes cannot directly engulf myelin debris because they are absent from lesion core. Here, we definitely showed that astrocytes could directly uptake myelin debris both in vitro and in vivo to effectively complement the clearance function. Therefore, it can be shown that astrocytes can exert myelin clearance effect directly and indirectly after spinal cord injury. The damaged myelin debris was transported to lysosomes for degradation through endocytosis pathways, finally resulting in excessive gliosis. This process may be a potential target for regulating neural tissue repair and excessive glia scar formation after SCI.

Bone-Derived Extracellular Vesicles: Novel Players of Interorgan Crosstalk.

An increasing number of studies have shown that bone plays an active role in regulating glucose metabolism, affects renal, and cardiovascular diseases and even influences the development of offspring. These novel findings have indicated that bone plays a much more important role in the human body than only providing physical support. However, further investigations of the mechanisms underlying the effects of bone are needed. Recently, extracellular vesicles (EVs) have received increased attention because they can transfer functional proteins, mRNAs, and miRNAs between cells/organs. After reviewing the existing evidence, we hypothesized that bone may be involved in interorgan communication via EVs. Further research exploring bone-derived EVs may facilitate the understanding of bone as a multifunctional organ.

Tenascin-C Modulates Cell Cycle Progression to Enhance Tumour Cell Proliferation through AKT/FOXO1 Signalling in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a disease with an extremely poor prognosis that is characterized by a rich extracellular matrix (ECM). Tenascin-C (TNC) is a component of the ECM and plays a role in tumour progression. In this study, we reported that TNC is overexpressed in PDAC tissues and is correlated with tumour stage and cyclin D1 expression. Cyclin D1 is key regulator of the cell cycle G1/S transition. Further experiments revealed that TNC promotes G1/S transition through AKT signalling. TNC/AKT increases the expression of cyclin D1 by enhancing the transcriptional activity of ß-catenin, whereas the translocation of FOXO1 from the nucleus results in the downregulation of p27Kip1. Cyclin D1 and p27Kip1 regulate the activity of cyclin D1-CDK4 complexes and retinoblastoma (Rb), and then they stimulate the progression of G1/S transition and tumour cell proliferation. In conclusion, TNC exerts its activating effect on the proliferation of pancreatic cancer cells in vitro and in vivo through its functional target AKT/FOXO1/ß-catenin. The molecular mechanisms that drive PDAC progression will be useful for the development of molecular markers and the evaluation of patient prognosis.

Tenascin-C induces migration and invasion through JNK/c-Jun signalling in pancreatic cancer.

Tenascin-C (TNC), a large extracellular matrix glycoprotein, has been reported to be associated with metastasis and poor prognosis in pancreatic cancer. However, the effects and mechanisms of TNC in pancreatic cancer metastasis largely remain unclear. We performed Transwell assays to investigate the effects of TNC on Capan-2, AsPC-1 and PANC-1 cells. In addition, western blot and RT-qPCR assays were used to examine potential TNC metastasis-associated targets, such as JNK/c-Jun, Paxillin/FAK, E-cadherin, N-cadherin, Vimentin, and MMP9/2. Lastly, we utilized a variety of methods, such as immunofluorescence, gelatin zymography and immunoprecipitation, to determine the molecular mechanisms of TNC in pancreatic cancer cell motility. The present study showed that TNC induced migration and invasion in pancreatic cancer cells and regulated a number of metastasis-associated proteins, including the EMT markers, MMP9 and Paxillin. Moreover, our data showed that TNC induced pancreatic cancer cells to generate an EMT phenotype and acquire motility potential through the activation of JNK/c-Jun signalling. In addition, TNC increased the DNA binding activity of c-Jun to the MMP9 promoter, an action likely resulting in increased MMP9 expression and activity. TNC/JNK also markedly induced the phosphorylation of Paxillin on serine 178, which is critical for the association between FAK and Paxillin and promoted the formation of focal adhesions. TNC/JNK initiates cell migration and invasion of pancreatic cancer cells through the promotion of EMT, the transactivation of MMP9 and the phosphorylation of Paxillin on serine 178. TNC may be a potential therapeutic target for treating pancreatic cancer metastasis.

Fractalkine/CX3CR1 induces apoptosis resistance and proliferation through the activation of the AKT/NF-κB cascade in pancreatic cancer cells.

Fractalkine (FKN, CX3CL1) is highly expressed in a majority of malignant solid tumours. Fractalkine is the only known ligand for CX3CR1. In this study, we performed an analysis to determine the effects of fractalkine/CX3CR1 on modulating apoptosis and explored the related mechanisms. The expression of fractalkine/CX3CR1 was detected by immunohistochemistry and western blotting. The levels of AKT/p-AKT, BCL-xl, and BCL-2 were detected by western blotting. Then, the effects of exogenous and endogenous fractalkine on the regulation of tumour apoptosis and proliferation were investigated. The mechanism of fractalkine/CX3CR1 on modulating apoptosis in cancer cells through the activation of AKT/NF-κB/p65 signals was evaluated. The effect of fractalkine on regulating cell cycle distribution was also tested. Fractalkine, AKT/p-AKT, and apoptotic regulatory proteins BCL-xl and BCL-2 were highly expressed in human pancreatic cancer tissues. In vitro, fractalkine/CX3CR1 promoted proliferation and mediated resistance to apoptosis in pancreatic cancer cells. The antiapoptotic effect of fractalkine was induced by the activation of AKT/NF-κB/p65 signalling in pancreatic cancer cells. The NF-κB/p65 contributes to promote the expressions of BCL-xl and BCL-2 and reduce caspase activity, thereby inhibiting apoptotic processes. Treatment with fractalkine resulted in the enrichment of pancreatic cancer cells in S phase with a concomitant decrease in the number of cells in G1 phase. The present study demonstrated the function of fractalkine in the activation of the AKT/NF-κB/p65 signalling cascade and mediation of apoptosis resistance in pancreatic cancer cells. Fractalkine/CX3CR1 could serve as a diagnostic marker and as a potential target for chemotherapy in early stage pancreatic cancer. Pancreatic cancer is characterized by local recurrence, neural invasion, or distant metastasis. The present study demonstrated the overexpression of fractalkine/CX3CR1 in pancreatic cancer tissues, indicating its important role in the tumourigenesis of pancreatic cancer, and suggested that the overexpression of fractalkine/CX3CR1 could serve as a diagnostic marker for pancreatic cancer. Moreover, we reveal the mechanism that fractalkine functions on the activation of the AKT/NF-κB/p65 signalling cascade and regulation of the antiapoptosis process in pancreatic cancer cells. Fractalkine/CX3CR1 could serve as an effective therapeutic target of chemotherapeutic and biologic agents in early stage pancreatic cancer.