Astaxanthin ameliorates dopaminergic neuron damage in paraquat-induced SH-SY5Y cells and mouse models of Parkinson's disease.

Parkinson's disease (PD) is the second largest neurodegenerative disorder caused by the decreased number of dopaminergic (DAc) neurons in the substantia nigra pars compacta (SNpc). There is evidence that oxidative stress can contribute degeneration of DAc neurons in SNpc which is mainly caused by apoptotic cell death. Thus, suppressing oxidative stress and apoptosis of DAc neurons is an effective strategy to mitigate the progress of PD. Astaxanthin (AST) is a carotenoid, which mainly exists in marine organisms and is a powerful biological antioxidant. In this study, we aimed to determine the neuroprotective effect of AST on paraquat (PQ) -induced models of PD in vitro and in vivo. Here, we showed that AST significantly enhanced cell survival of SH-SY5Y cells against PQ toxicity by suppressing apoptotic cell death and oxidative stress. Moreover, we found that AST significantly ameliorated PQ-induced behavioral disorders associated with PD in C57BL/6 J mice and the damage to DAc neurons in the SNpc of mice. Lastly, we found that the neuroprotective effects of AST were conducted through inhibiting PQ-induced activation of MAPK signaling. In conclusion, our study indicates that AST had a strong protective effect on PQ-induced oxidative stress and antagonized apoptotic cell death in SH-SY5Y cells and PQ-induced mice PD model, which might provide new insights of AST for PD treatment.

Ponicidin Induces Apoptosis of Murine Melanoma by Inhibiting the NF-κB Signaling Pathway.

Ponicidin (PON), a diterpenoid extracted from the Chinese herb Rubescens, has been reported to be a therapeutic cytotoxic drug for the treatment of various types of human cancers. According to the statistics, the incidence of malignant melanoma is increasing year by year and the degree of malignancy is extremely high, so early treatment is very important. In the present study, we demonstrated the antitumor effect of PON on melanoma in vitro and in vivo. Cell Counting Kit-8 (CCK-8) assay was used to detect cell proliferation rate, crystal violet staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) kit was used to detect cell apoptosis, and Western blotting was used to detect the expression of apoptotic indicators and related signaling pathway proteins. Finally, the tumor-bearing mouse model was constructed. Treating melanoma B16F0 and B16F10 cells with different concentrations (10 and 20 µmol/L) of PON magnificantly decreased cell viability. In addition, PON significantly activates the expression of pro-apoptotic proteins, including cleaved-poly(ADP-ribose)polymerase (PARP) (cl.PARP), Bak and Bim proteins, and also inhibits the expression of anti-apoptotic protein Mcl-1 and nuclear transcription factor nuclear factor-kappaB (NF-κB) in melanoma cells. Lastly, PON effectively inhibits the growth of mouse xenografts in vivo. These results suggest that PON induces apoptosis of melanoma cells may be achieved by inhibiting NF-κB signal pathway, but the specific mechanism remains to be further elucidated. Taken together, PON may serve as an effective potential drug for the treatment of melanoma.

Influence of RRM, RGG and Potential Phosphorylated Sites in Cold-Inducible Protein RBM3 on its Subcellular Localization and Neuroprotective Effects.

BACKGROUND: As a potent mediator of hypothermic neuroprotection, the cold-inducible protein RBM3 is characterized with one RNA-recognition motifs (RRM) and one arginine-glycine-rich (RGG) domain. It is known that these conserved domains are required for nuclear localization in some RNA-binding proteins. However, little is known about the actual role of RRM and RGG domains in subcellular localization of RBM3. METHODS: To clarify it, various mutants of human Rbm3 gene were constructed. Plasmids were transfected into cells and the localization of RBM3 protein and its varias mutants in cells and role in neuroprotection. RESULTS: In human neuroblastoma SH-SY5Y cells, either a truncation of RRM domain (aa 1-86) or RGG domain (aa 87-157) led to an obvious cytoplasmic distribution, compared to a predominant nuclear localization of whole RBM3 protein (aa 1-157). In contrast, mutants in several potential phosphorylated sites of RBM3, including Ser102, Tyr129, Ser147, and Tyr155, did not alter the nuclear localization of RBM3. Similarly, mutants in two Di-RGG motif sites also did not affect the subcellular distribution of RBM3. Lastly, the role of Di-RGG motif in RGG domains was further investigated. The mutant of double arginines in either Di-RGG motif-1 (Arg87/90) or -2 (Arg99/105) exhibited a higher cytoplasmic localization, indicating that both Di-RGG motifs are required for nucleic localization of RBM3. CONCLUSIONS: Our data suggest that RRM and RGG domains are both required for the nuclear localization of RBM3, with two Di-RGG domain being crucial for nucleocytoplasmic shuttling of RBM3.

Neural Cell Adhesion Molecule Regulates Osteoblastic Differentiation Through Wnt/ß-Catenin and PI3K-Akt Signaling Pathways in MC3T3-E1 Cells.

Neural cell adhesion molecule (NCAM) is involved in cell multi-directional differentiation, but its role in osteoblast differentiation is still poorly understood. In the present study, we investigated whether and how NCAM regulates osteoblastic differentiation. We found that NCAM silencing inhibited osteoblast differentiation in pre-osteoblastic MC3T3-E1 cells. The function of NCAM was further confirmed in NCAM-deficient mesenchymal stem cells (MSCs), which also had a phenotype with reduced osteoblastic potential. Moreover, NCAM silencing induced decrease of Wnt/ß-catenin and Akt activation. The Wnt inhibitor blocked osteoblast differentiation, and the Wnt activator recovered osteoblast differentiation in NCAM-silenced MC3T3-E1 cells. We lastly demonstrated that osteoblast differentiation of MC3T3-E1 cells was inhibited by the PI3K-Akt inhibitor. In conclusion, these results demonstrate that NCAM silencing inhibited osteoblastic differentiation through inactivation of Wnt/ß-catenin and PI3K-Akt signaling pathways.

Expression regulation of cold-inducible protein RBM3 by FAK/Src signaling for neuroprotection against rotenone under mild hypothermia.

Mild hypothermia is a well-established technique for alleviating neurological injuries in clinical surgery. RNA-binding protein motif 3 (RBM3) has been identified as a crucial factor in mediating hypothermic neuroprotection, providing its induction as a promising strategy for mimicking therapeutic hypothermia. However, little is known about molecular control of RBM3 and signaling pathways affected by hypothermia. In the present study, human SH-SY5Y neuroblastoma cells were used as a neural cell model. Screening of signaling pathways showed that cold exposure led to inactivation of ERK and AMPK pathways, and activation of FAK and PLCγ pathways, with activities of p38, JNK and AKT pathways moderately changed. Next, various small molecule inhibitors specific to these signaling pathways were applied. Interestingly, only FAK-specific inhibitor exhibited a significant inhibitory effect on hypothermia-induced RBM3 gene transcription and protein expression. Likewise, FAK silencing using siRNA technique significantly abrogated the induction of RBM3 by hypothermia. Moreover, FAK inhibition accounted for an inactivation of Src, a known kinase downstream of FAK. Next, either the silencing of Src by siRNA or its inactivation by a chemical inhibitor, strongly blocked the induction of RBM3 by cooling. Notably, in HEK293 and PC12 cells, FAK/Src activation was also shown to be indispensable for hypothermia-stimulated RBM3 expression. Lastly, the CCK8 and Western blot assays showed that both FAK/Src inacitivation and their knockdown substantially abrogate the neuroprotective effects of mild hypothermia against rotenone in SH-SY5Y cells. These data suggest that FAK/Src signaling axis regulates the transcription of Rbm3 gene and mediates neuroprotective effects of mild hypothermia.

Neural cell adhesion molecule regulates chondrocyte hypertrophy in chondrogenic differentiation and experimental osteoarthritis.

Chondrocyte hypertrophy-like change is an important pathological process of osteoarthritis (OA), but the mechanism remains largely unknown. Neural cell adhesion molecule (NCAM) is highly expressed and involved in the chondrocyte differentiation of mesenchymal stem cells (MSCs). In this study, we found that NCAM deficiency accelerates chondrocyte hypertrophy in articular cartilage and growth plate of OA mice. NCAM deficiency leads to hypertrophic chondrocyte differentiation in both murine MSCs and chondrogenic cells, in which extracellular signal-regulated kinase (ERK) signaling plays an important role. Moreover, NCAM expression is downregulated in an interleukin-1ß-stimulated OA cellular model and monosodium iodoacetate-induced OA rats. Overexpression of NCAM substantially inhibits hypertrophic differentiation in the OA cellular model. In conclusion, NCAM could inhibit hypertrophic chondrocyte differentiation of MSCs by inhibiting ERK signaling and reduce chondrocyte hypertrophy in experimental OA model, suggesting the potential utility of NCAM as a novel therapeutic target for alleviating chondrocyte hypertrophy of OA.

Benzoylaconitine Inhibits Production of IL-6 and IL-8 via MAPK, Akt, NF-κB Signaling in IL-1ß-Induced Human Synovial Cells.

Benzoylaconitine (BAC), the main hydrolysate of aconitine, is a lower toxic monoester type alkaloid considered as the pharmacodynamic constituent in Aconitum species. In this study, the effects and mechanisms of BAC on production of inflammatory cytokines interleukin (IL)-6 and IL-8 were investigated in IL-1ß-stimulated human synovial SW982 cells. The SW982 cells were incubated with BAC (0, 5 and 10 µM) before stimulating with IL-1ß (10 ng/mL). The results revealed that BAC suppressed gene and protein expression of IL-6 and IL-8 induced by IL-1ß. BAC decreased activation of mitogen-activated protein kinase (MAPK) and phosphorylation of Akt. BAC also inhibited degradation of inhibitor of kappaB (IκB)-α, phosphorylation and nuclear transposition of p65 protein. The results demonstrate that BAC exerts an anti-inflammatory effect dependent on MAPK, Akt and nuclear factor-κB (NF-κB) pathways in human synovial cells stimulated with IL-1ß, suggesting that BAC may be exploited as a potential therapeutic agent for rheumatoid arthritis (RA) treatment.

Celastrol Induces Necroptosis and Ameliorates Inflammation via Targeting Biglycan in Human Gastric Carcinoma.

Celastrol, a triterpene isolated from the root of traditional Chinese medicine Thunder of God Vine, possesses anti-cancer and anti-inflammatory activity to treat rheumatoid disease or as health product. Necroptosis is considered as a new approach to overcome chemotherapeutics resistance. However, whether celastrol exerts necroptosis leading to gastric cancer cell death is still unclear. Here, for the first time we showed that celastrol induced necroptosis in HGC27 and AGS gastric cancer cell lines. More importantly, celastrol down-regulated biglycan (BGN) protein, which is critical for gastric cancer migration and invasion. Furthermore, celastrol activated receptor-interacting protein 1 and 3 (RIP1 and RIP3) and subsequently promoted the translation of mixed-lineage kinase domain-like (MLKL) from cytoplasm to plasma membrane, leading to necroptosis of gastric cancer cell, which was blocked by over-expression BGN. In addition, celastrol suppressed the release of pro-inflammatory cytokines TNF-α and IL-8 in HGC27 and AGS cells, which was reversed by over-expression BGN. Taken together, we identified celastrol as a necroptosis inducer, activated RIP1/RIP3/MLKL pathway and suppressed the level of pro-inflammatory cytokines by down-regulating BGN in HGC-27 and AGS cells, which supported the feasibility of celastrol in gastric cancer therapy.

Mild Hypothermia Prevents NO-Induced Cytotoxicity in Human Neuroblastoma Cells Via Induction of COX-2.

The cold-inducible protein RBM3 mediates hypothermic neuroprotection against nitric oxide (NO)-induced cell death. Meanwhile, it is well-known that cyclooxygenase-2 (COX-2) is upregulated by RBM3 in several types of cells; however, it is still unclear whether COX-2 contributes to the neuroprotective effects of mild hypothermia/RBM3 against NO-induced cell death. Using human SH-SY5Y neuroblastoma cells, it was revealed that NO remarkably downregulates the expression of COX-2 at both mRNA and protein levels. When COX-2 was silenced using siRNA technique, cells became more sensitive to NO-induced cell death. Conversely, the overexpression of COX-2 significantly prevented NO-induced cell death in SH-SY5Y cells, indicating a pro-survival role of COX-2. Upon mild hypothermia pre-treatment, COX-2 was notably induced at both mRNA and protein levels; however, COX-2 silencing abrogated hypothermia-related neuroprotection against NO-induced cell death. Furthermore, it was revealed that either silencing or overexpression of RBM3 had no effects on the expression of COX-2 in SH-SY5Y cells. These findings suggest that mild hypothermia could protect neuroblastoma cells against NO-induced cell death by inducing COX-2 in a RBM3-independent manner.

Sine oculis homeobox 1 promotes proliferation and migration of human colorectal cancer cells through activation of Wnt/ß-catenin signaling.

Sine oculis homeobox 1 (Six1) is a homeodomain transcription factor that is aberrantly expressed in a variety of human cancers, including colorectal cancer (CRC). Six1 has been reported to play a key role in the proliferation and migration of CRC cells but the underlying molecular mechanisms are still poorly characterized. In the present study, we found that Six1 overexpression promoted the proliferation and migration of CRC cells. Consistently, Six1 knockdown (KD) significantly inhibited proliferation and migration of CRC cells. In addition, we showed that Six1 promoted proliferation and migration of CRC cells through activation of Wnt/ß-catenin signaling, as evidenced by promotion of nuclear localization of ß-catenin. Silencing of ß-catenin expression with siRNA or inhibiting Wnt signaling with a specific inhibitor, xav939, significantly blocked Six1-induced nuclear localization of ß-catenin and mitigated Six1-promoted proliferation and migration of CRC cells. We further confirmed the involvement of ß-catenin in Six1-promoted proliferation and migration of CRC cells by activation of Wnt signaling with lithium chloride (LiCl) in Six1 KD CRC cells and results showed that LiCl restores defective ß-catenin nuclear localization and proliferation and migration of CRC cells. Taken together, these results suggest that Six1 homeoprotein promotes the proliferation and migration of CRC cells by activating the Wnt/ß-catenin signaling pathway, and strategies targeting Six1 may be promising for the treatment of CRC.

Osthole Synergizes With HER2 Inhibitor, Trastuzumab in HER2-Overexpressed N87 Gastric Cancer by Inducing Apoptosis and Inhibition of AKT-MAPK Pathway.

Background and Purpose: Although trastuzumab has shown considerable activity in the treatment of HER2-positive breast and gastric cancers, a significant proportion of patients do not respond to trastuzumab. Recent studies revealed that osthole, an active coumarin isolated from Cnidium monnieri (L.) Cusson possesses potent anti-tumor activity. Here, we for the first time investigated the anti-tumor activity of trastuzumab in combination with osthole in HER2-overexpressing cancers. Materials and Methods: N87 and SK-BR-3 cell lines, which were HER2-overexpressing cancer cells were used in our study. Cell Counting Kit-8 (CCK-8) assay was utilized to test the inhibitory effects of trastuzumab plus osthole. Combination index (CI) values were calculated using the Chou-Talalay method. Fluorescence-Activated Cell Sorter (FACS) assay was used to examine the cell cycle change and apoptosis upon combinatorial treatment. N87 tumor xenografts were established to evaluate in vivo effects of trastuzumab plus osthole. In addition, molecular mechanisms were analyzed by Western blot in vitro and in vivo. Results: As shown in our study, osthole alone exhibited effective anti-tumor activity against HER2-overexpressed N87 gastric cancer cells and SK-BR-3 breast cancer cells, which may be attributed to cell cycle arrest on G2/M phase and apoptosis. More importantly, our data demonstrated that trastuzumab plus osthole was much more potent than either agent alone in inhibiting the growth of N87 cancer cells in vitro and in vivo, which may be partly explained by the enhanced apoptosis upon the combinatorial treatment. Besides these, we also observed a significant decrease on the phosphorylation of AKT and MAPK in N87 cells when treated with trastuzumab plus osthole compared to either agent alone. Further data from N87 tumor xenografts revealed that trastuzumab plus osthole exerted their synergistic effects mainly on AKT signaling pathway. Conclusion: Collectively, these results support the clinical development of combination osthole with trastuzumab for the treatment of HER2-overexpressed gastric cancer.

Fengshi Gutong Capsule Attenuates Osteoarthritis by Inhibiting MAPK, NF-κB, AP-1, and Akt Pathways.

Background and purpose: Fengshi Gutong capsule (FSGTC), a traditional herbal formula, has been used clinically in China for the treatment of arthritis. However, the mechanism underlying the therapeutic effects of FSGTC on osteoarthritis (OA) has not been elucidated. The present study investigated the function and mechanisms of FSGTC in rat OA model and interleukin (IL)-1ß-stimulated synovial cells. Materials and methods: Rat OA model was established by intra-articular injection containing 4% papain. IL-1ß-induced SW982 cells were used as an OA cell model. Safranin-O-Fast green (S-O) and hematoxylin-eosin (HE) stainings were used to observe the changes in cartilage morphology. Enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (qPCR) detected the expression of inflammatory cytokines. In addition, molecular mechanisms were analyzed by Western blot in the OA cell model. Results: FSGTC treatment significantly relieved the degeneration of cartilage and reduced the contents of tumor necrosis factor-α (TNF-α) and IL-6 in the serum in papain-induced OA rats. FSGTC also reduced the protein and mRNA levels of IL-6 and IL-8 in IL-1ß-stimulated SW982 cells. Moreover, it inhibited the phosphorylation levels of ERK (extracellular signal-related kinase), JNK (c-Jun N-terminal kinase), p38, Akt (protein kinase B), and c-Jun. It also decreased the extent of IκBα degradation and p65 protein translocation into the nucleus. Conclusion: The current data confirmed the protective effects of FSGTC in the rat and OA cell models. The results suggested that FSGTC reduced the production of inflammatory mediators via restraining the activation of mitogen-activated protein kinases (MAPK), nuclear factor kappa B (NF-κB), activator protein-1 (AP-1), and Akt.

Biglycan, a Nitric Oxide-Downregulated Proteoglycan, Prevents Nitric Oxide-Induced Neuronal Cell Apoptosis via Targeting Erk1/2 and p38 Signaling Pathways.

Nitric oxide (NO), a gaseous signaling molecule, induces apoptosis and mediates neurodegenerative diseases and brain injury. Biglycan (BGN), a member of the small leucine-rich proteoglycan family, was demonstrated to exert anti-apoptosis function in various disease models. However, little is known about the effect of BGN on NO-induced neurotoxicity. Here, for the first time, we reported that BGN protects against NO-induced apoptosis in human neuroblastoma SH-EP1 cells. This is supported by the finding that sodium nitroprusside (SNP), a NO donor, triggered downregulation of BGN in SH-EP1 cells, and over-expression of BGN strikingly attenuated NO-induced nuclear fragmentation and apoptosis of neuronal cells. More importantly, BGN remarkably blocked NO-induced phosphorylation of Erk1/2 and p38 signaling, but not JNK MAPK pathway in neuronal cells. Furthermore, inhibiting Erk1/2 by U0126 or p38 by SB203580 partially protected against NO-induced cell death. Conversely, downregulation of BGN by siRNA aggravated NO-induced neuronal cell death, which was not attenuated by U0126 or SB203580. These findings indicated that BGN, downregulated by NO, prevents NO-induced neuronal cell apoptosis via targeting Erk1/2 and p38 signaling pathways. Our results strongly suggest that BGN could be explored for the prevention of NO-induced neurodegenerative disorders.

Neuroprotective Effects of Proanthocyanidins, Natural Flavonoids Derived From Plants, on Rotenone-Induced Oxidative Stress and Apoptotic Cell Death in Human Neuroblastoma SH-SY5Y Cells.

Proanthocyanidins (PA) are natural flavonoids widely present in many vegetables, fruits, nuts and seeds, and especially in grape seed. In the present study, we examined the neuroprotective effects of PA and the underlying molecular mechanism in rotenone model of Parkinson's disease (PD). We found that pretreatment with PA significantly reduced rotenone-induced oxidative stress in human neuroblastoma SH-SY5Y dopaminergic cells. In addition, PA markedly enhanced cell viability against rotenone neurotoxicity and considerably blocked rotenone-induced activation of caspase-9, caspase-3, and cleavage of poly (ADP-ribose) polymerase (PARP), biochemical features of apoptosis. Further study demonstrated that the anti-apoptotic effect of PA was mediated by suppressing p38, JNK, and ERK signaling, and inhibitors of these three signaling pathways reproduced the protective effect of PA separately. In summary, our results demonstrated that PA mitigated rotenone-induced ROS generation and antagonized apoptosis in SH-SY5Y cells by inhibiting p38, JNK, and ERK signaling pathways, and it may provide a new insight of PA in PD therapy.

Cold Shock Induced Protein RBM3 but Not Mild Hypothermia Protects Human SH-SY5Y Neuroblastoma Cells From MPP+-Induced Neurotoxicity.

The cold shock protein RBM3 can mediate mild hypothermia-related protection in neurodegeneration such as Alzheimer's disease. However, it remains unclear whether RBM3 and mild hypothermia provide same protection in model of Parkinson's disease (PD), the second most common neurodegenerative disorder. In this study, human SH-SY5Y neuroblastoma cells subjected to insult by 1-methyl-4-phenylpyridinium (MPP+) served as an in-vitro model of PD. Mild hypothermia (32°C) aggravated MPP+-induced apoptosis, which was boosted when RBM3 was silenced by siRNA. In contrast, overexpression of RBM3 significantly reduced this apoptosis. MPP+ treatment downregulated the expression of RBM3 both endogenously and exogenously and suppressed its induction by mild hypothermia (32°C). In conclusion, our data suggest that cold shock protein RBM3 provides neuroprotection in a cell model of PD, suggesting that RBM3 induction may be a suitable strategy for PD therapy. However, mild hypothermia exacerbates MPP+-induced apoptosis even that RBM3 could be synthesized during mild hypothermia.

Cold-Inducible Protein RBM3 Protects UV Irradiation-Induced Apoptosis in Neuroblastoma Cells by Affecting p38 and JNK Pathways and Bcl2 Family Proteins.

Induced by hypothermia, cold-inducible protein RBM3 (RNA-binding protein motif 3), has been implicated in neuroprotection against various toxic insults such as hypoxia and ischemia. However, whether mild hypothermia and RBM3 prevent neural cells from UV irradiation-elicited apoptosis is unclear. In the present study, human neuroblastoma cell line SH-SY5Y was used as a cell model for neural cell death, and it was demonstrated that mild hypothermia protects SH-SY5Y cells from UV irradiation-induced apoptosis. However, the protective effect of mild hypothermia was abrogated when RBM3 was silenced. Conversely, the overexpression of RBM3 rescued SH-SY5Y cells from UV-induced apoptosis, as indicated by the decreased levels of cleaved caspase-3 and PARP, and increased cell survival. The analysis on the mechanism underlying RBM3-mediated neuroprotection against UV insult showed that RBM3 could substantially block the activation of p38 and JNK signaling pathways. In addition, the overexpression of RBM3 reduced the expression of pro-apoptotic proteins Bax and Bad, leaving the pro-survival protein Bcl-2 unaffected. In conclusion, RBM3 is the key mediator of mild hypothermia-related protection against UV in neuroblastoma cells, and the neuroprotective effect might be exerted through interfering with pro-apoptotic signaling pathways p38 and JNK and regulating pro-apoptotic proteins Bax and Bad.

Anti-inflammatory effects of pitavastatin in interleukin-1ß-induced SW982 human synovial cells.

The present study shows the basis for the anti-inflammatory effects of pitavastatin in interleukin (IL)-1ß-induced human synovial cells. The SW982 cells were pretreated with pitavastatin at different concentrations (5µM and 10µM), followed by IL-1ß (10ng/mL) stimulation. The results showed that pitavastatin inhibited the expression of inflammatory mediators IL-6 and IL-8. Furthermore, pitavastatin inhibited the phosphorylation of p38, extracellular signal-related kinase (ERK), c-jun N-terminal kinase (JNK) and protein kinase B (Akt). It also suppressed the degradation of I kappa B alpha and blocked p65 translocation into the nucleus. These findings suggest that the mechanism underlying the inhibitory effects of pitavastatin on IL-1ß-induced IL-6 and IL-8 release might be mediated by the suppression of mitogen-activated protein kinase (MAPK), Akt, and nuclear factor-κB (NF-κB) signaling pathways. These results may also indicate that pitavastatin may be potentially utilized as an effective therapeutic agent for the treatment of osteoarthritis.

Increase of tensile strength and toughness of bio-based diglycidyl ether of bisphenol A with chitin nanowhiskers.

It is challenging to reinforce and toughen thermoset epoxy resins. We describe a slurry-compounding technique to transfer a uniform dispersion of chitin nanowhiskers (CW) in ethanol into an epoxy matrix. The incorporation of the hydrophilic CW reinforces the oil-soluble diglycidyl ether of bisphenol A (DGEBA). The resultant CW/epoxy bionanocomposites were transparent and showed considerably enhanced thermal and mechanical properties with tensile strength, modulus, toughness, and elongation at break being increased by 49%, 16%, 457%, and 250%, with only 2.5 wt.% CW. This improvement in strength and toughness is rare for thermoset epoxy/rigid nanofiller systems. We hypothesize that CW with many free amine groups could function not only as a nanofiller but also as a macromolecular polyamine hardener that participates in epoxy curing. The strong covalent interaction between the filler and the matrix allowed for efficient load transfer across the interfaces, which accounted for the greater strength and toughness.

NCAM affects directional lamellipodia formation of BMSCs via ß1 integrin signal-mediated cofilin activity.

The neural cell adhesion molecule (NCAM), a key member of the immunoglobulin-like CAM family, was reported to regulate the migration of bone marrow-derived mesenchymal stem cells (BMSCs). However, the detailed cellular behaviors including lamellipodia formation in the initial step of directional migration remain largely unknown. In the present study, we reported that NCAM affects the lamellipodia formation of BMSCs. Using BMSCs from Ncam knockout mice we found that Ncam deficiency significantly impaired the migration and the directional lamellipodia formation of BMSCs. Further studies revealed that Ncam knockout decreased the activity of cofilin, an actin-cleaving protein, which was involved in directional protrusions. To explore the molecular mechanisms involved, we examined protein tyrosine phosphorylation levels in Ncam knockout BMSCs by phosphotyrosine peptide array analyses, and found that the tyrosine phosphorylation level of ß1 integrin, a protein upstream of cofilin, was greatly upregulated in Ncam-deficient BMSCs. Notably, by blocking the function of ß1 integrin with RGD peptide or ROCK inhibitor, the cofilin activity and directional lamellipodia formation of Ncam knockout BMSCs could be rescued. Finally, we found that the effect of NCAM on tyrosine phosphorylation of ß1 integrin was independent of the fibroblast growth factor receptor. These results indicated that NCAM regulates directional lamellipodia formation of BMSCs through ß1 integrin signal-mediated cofilin activity.

RNA-binding protein RBM3 prevents NO-induced apoptosis in human neuroblastoma cells by modulating p38 signaling and miR-143.

Nitric oxide (NO)-induced apoptosis in neurons is an important cause of neurodegenerative disease in humans. The cold-inducible protein RBM3 mediates the protective effects of cooling on apoptosis induced by various insults. However, whether RBM3 protects neural cells from NO-induced apoptosis is unclear. This study aimed to investigate the neuroprotective effect of RBM3 on NO-induced apoptosis in human SH-SY5Y neuroblastoma cells. Firstly, we demonstrated that mild hypothermia (32 °C) induces RBM3 expression and confers a potent neuroprotective effect on NO-induced apoptosis, which was substantially diminished when RBM3 was silenced by siRNA. Moreover, overexpression of RBM3 exhibited a strong protective effect against NO-induced apoptosis. Signaling pathway screening demonstrated that only p38 inhibition by RBM3 provided neuroprotective effect, although RBM3 overexpression could affect the activation of p38, JNK, ERK, and AKT signaling in response to NO stimuli. Notably, RBM3 overexpression also blocked the activation of p38 signaling induced by transforming growth factor-ß1. Furthermore, both RBM3 overexpression and mild hypothermia abolished the induction of miR-143 by NO, which was shown to mediate the cytotoxicity of NO in a p38-dependent way. These findings suggest that RBM3 protects neuroblastoma cells from NO-induced apoptosis by suppressing p38 signaling, which mediates apoptosis through miR-143 induction.