Upregulated Expression of TRIM32 Is Involved in Schwann Cell Differentiation, Migration and Neurite Outgrowth After Sciatic Nerve Crush.

Tripartite motif containing 32 (TRIM32), a member of the tripartite motif (TRIM) family, plays an indispensable role in myoblast proliferation. It also regulates neuron and skeletal muscle stem cell differentiation. Although it is of great importance, we know little about the roles of TRIM32 during peripheral nervous system injury. Here, we examined the dynamic changes of TRIM32 in acute sciatic nerve crush (SNC) model. After crush, TRIM32 rapidly increased and reached the climax at 1 week but then gradually declined to the normal level at 4 weeks post-injury. Meanwhile, we observed similar changes of Oct-6. What is more, we found co-localization of TRIM32 with S100 and Oct-6 in 1-week-injured tissues using double immunofluorescent staining. In further vitro experiments, enhancive expression of TRIM32 was detected during the process of cyclic adenosine monophosphate (cAMP)-induced Schwann cell differentiation and nerve growth factor (NGF)-induced PC12 cell neurite outgrowth. More interestingly, specific si-TRIM32-transfected RSC96 cells exhibited obvious reduction in the ability of migration. Taken together, we inferred that upregulated TRIM32 was not only involved in the differentiation and migration of Schwann cells but the neurite elongation after SNC.

Involvement of upregulated SYF2 in Schwann cell differentiation and migration after sciatic nerve crush.

SYF2 is a putative homolog of human p29 in Saccharomyces cerevisiae. It seems to be involved in pre-mRNA splicing and cell cycle progression. Disruption of SYF2 leads to reduced α-tubulin expression and delayed nerve system development in zebrafish. Due to the potential of SYF2 in modulating microtubule dynamics in nervous system, we investigated the spatiotemporal expression of SYF2 in a rat sciatic nerve crush (SNC) model. We found that SNC resulted in a significant upregulation of SYF2 from 3 days to 1 week and subsequently returned to the normal level at 4 weeks. At its peak expression, SYF2 distributed predominantly in Schwann cells. In addition, upregulation of SYF2 was approximately in parallel with Oct-6, and numerous Schwann cells expressing SYF2 were Oct-6 positive. In vitro, we observed enhanced expression of SYF2 during the process of cyclic adenosine monophosphate (cAMP)-induced Schwann cell differentiation. SYF2-specific siRNA-transfected Schwann cells did not show significant morphological change in the process of Schwann cell differentiation. Also, we found shorter and disorganized microtubule structure and a decreased migration in SYF2-specific siRNA-transfected Schwann cells. Together, these findings indicated that the upregulation of SYF2 was associated with Schwann cell differentiation and migration following sciatic nerve crush.

Dynamic change of Numbl expression after sciatic nerve crush and its role in Schwann cell differentiation.

Numbl, as a conserved homolog of Drosophila Numb, has been implicated in early development of the nervous system, but its expression and roles in nervous system lesion and repair remained unknown. Here, we performed an acute sciatic nerve injury model in adult rats and studied the dynamic changes of Numbl expression in the sciatic nerve. Temporally, Numbl expression was sharply decreased after sciatic nerve crush and reached a valley at day 7. Spatially, Numbl was widely expressed in the normal sciatic nerve, including axons and Schwann cells, whereas, after injury, Numbl expression was decreased predominantly in Schwann cells. In vitro, we induced Schwann cell differentiation with cAMP and found that Numbl expression was decreased in the differentiated process. Depletion of Numbl could promote Schwann cell differentiation. In addition, we demonstrated that in vitro myelination was suppressed by overexpression of Numbl in Schwann cells. Collectively, we hypothesized peripheral nerve injury induced a downregulation of Numbl in the sciatic nerve, which was associated with Schwann cell differentiation.

ß-1,4-Galactosyltransferase I involved in Schwann cells proliferation and apoptosis induced by tumor necrosis factor-alpha via the activation of MAP kinases signal pathways.

ß-1,4-galactosyltransferase-I (ß-1,4-GalT-I) plays a critical role in the initiation and maintenance of peripheral nervous system inflammatory reaction. However, the exact function of ß-1,4-GalT-I in the regulation of SCs proliferation and apoptosis remains unclear. In this study, we found that low concentration of tumor necrosis factor-alpha (TNF-α) induced SCs proliferation, while high concentration of TNF-α induced SCs apoptosis. Meanwhile, the expressions of ß-1,4-GalT-I, TNFR1, and TNFR2 were changed following. When ß-1,4-GalT I overexpression, low concentration of TNF-α-induced SCs proliferation was partially repressed. Concurrently, the activity of ERK1/2 was decreased. While knocking down ß-1,4-GalT I expression, high concentration of TNF-α-induced SCs apoptosis was partially rescued. Consistent with this, the activity of P38 and JNK were decreased. We also found anti-TNFR2 antibody suppressed low concentration of TNF-α-induced SCs proliferation, while anti-TNFR1 antibody inhibited high concentration of TNF-α-induced SCs apoptosis. Thus, present data show that ß-1,4-GalT I may play an important role in SCs proliferation and apoptosis induced by TNF-α via different signal pathways and TNFR.

Overexpression of ZEB1 relates to metastasis and invasion in osteosarcoma.

BACKGROUND: This study aimed to investigate the expression of ZEB1 in osteosarcoma tissues and to discuss the relationship between ZEB1 expression and osteosarcoma metastasis. METHODS: Using RT-PCR and Western blotting, the mRNA and protein expressions of ZEB1 in the osteosarcoma and normal bone tissues were detected. Using the RNA interference technique, the expression of ZEB1 in the human osteosarcoma MG-63 cell line was downregulated, and the changes in the invasion of MG-63 cells were examined. RESULTS: The positive mRNA expression rate of ZEB1 in the osteosarcoma tissues was significantly higher than that in normal bone tissue (P < 0.05). The protein expression level of ZEB1 in the sarcoma tissues from patients with positive lung metastasis was significantly higher than that from patients without lung metastasis (P < 0.05). After the transfection of ZEB1 siRNA into the MG-63 cells, the protein expression of ZEB1 was significantly reduced (P < 0.05), and the number of cells that passed through the Transwell chamber was significantly lower than that in the non-transfected control group as well as the transfected control group (P < 0.05). CONCLUSIONS: The overexpression of ZEB1 in osteosarcoma may be related to the carcinogenesis and development as well as metastasis and invasion of osteosarcoma.

Expressions of forkhead class box O 3a on crushed rat sciatic nerves and differentiated primary Schwann cells.

Forkhead box-containing protein, class O 3 a (FOXO3a), an Akt downstream target, plays an important role in peripheral nervous system. FOXO3a shares the ability to be inhibited and translocated from the nucleus on phosphorylation by proteins such as Akt/PKB in the PI3K signaling pathway. To elucidate the expression and possible function of FOXO3a in lesion and repair, we performed an acute sciatic nerve crush model and studied differential expressions of FOXO3a. We observed that expressions of FOXO3a in Schwann cells (SCs) of the peripheral nervous system and cAMP-induced differentiation were dynamically regulated. Western blot analysis showed FOXO3a level significantly decreased post injury. Moreover, Immunofluorescence double labeling suggested the changes were striking especially in SCs. In vitro, Western blot analysis showed that the expression of FOXO3a was decreased in cAMP-induced differentiated primary SCs. The FOXO3a siRNA-transfected SCs treated by cAMP promote differentiation of SCs through the PI3K/Akt pathway. The results indicate that FOXO3a plays an important role during differentiation of SCs.

The relationship between Src-suppressed C kinase substrate and ß-1,4 galactosyltransferase-I in the process of lipopolysaccharide-induced TNF-α secretion in rat primary astrocytes.

Src-suppressed C kinase substrate (SSeCKS), a protein kinase C substrate, is a major lipopolysaccharide (LPS) response protein. In addition, ß-1,4 Galactosyltransferase-I (ß-1,4-GalT-I) also plays an important role in the inflammation reactions of nervous system. It was reported that both SSeCKS and ß-1,4-GalT-I were involved in the LPS-induced tumor necrosis factor-alpha (TNF-α) expression in rat primary astrocytes. However, the functional interaction between SSeCKS and ß-1,4-GalT-I in the LPS-induced TNF-α secretion remains unclear. Therefore, in this study, using the inflammation model of astrocytes treated by LPS in vitro, we found that the changed expressions of SSeCKS and ß-1,4-GalT-I participated in LPS-induced TNF-α secretion through p38, JNK, and ERK signal transduction pathways in rat primary astrocytes. Knockdown by small-interfering RNAs (siRNAs) or overexpression of SSeCKS and ß-1,4-GalT-I could influence Mitogen-activated protein kinases (MAPKs) signaling pathways activation and TNF-α secretion. Besides, we confirmed that knockdown of SSeCKS could prevent the induction of ß-1,4-GalT-I in this process. Inversely, ß-1,4-GalT-I had no significant effect on SSeCKS expression in the same way. In summary, our data indicated that SSeCKS could regulate LPS-induced TNF-α secretion through ß-1,4-GalT-I in rat primary astrocytes.

ß-1,4-Galactosyltransferase-involved in lipopolysaccharide-induced adhesion of Schwann cells.

OBJECTIVE AND DESIGN: The carbohydrate moieties of glycoprotein are associated with some inflammatory diseases by affecting a wide range of biological functions of cells. This study aimed to investigate the role of ß-1,4-galactosyltransferase-I (ß-1,4-GalT-I) in adhesion of Schwann cells during inflammation. SUBJECTS: A rat Schwann cell line, RSC 96 was used. METHODS: We used western blotting to detect the expression of ß-1,4-GalT-I. Flow cytomety was used to measure the galactosylation of glycoproteins on cell surfaces. Immunofluorescent staining was used to examine the expression of α6 integrin, focal adhesion kinase (FAK) and F-actin. Tyrosine phosphorylation of FAK was detected by immunoprecipitation. An adhesion assay was performed to investigate the adhesion of Schwann cells. One-way ANOVA was used to compare differences between the operated and the control group. RESULTS: Schwann cell adhesion was induced by LPS stimulation and was accompanied by upregulation of ß-1,4-GalT-I expression and galactosylation of glycoproteins. There was a change of localization of FAK and cytoskeleton organization in LPS treated cells compared with control cells. The pretreated cells enhanced tyrosine phosphorylation of FAK compared with control cells in the adhesion process. With the increased cell surface expression of α6 integrin and ß-1,4-GalT-I, the adhesion of Schwann cells on laminin was increased as well. CONCLUSIONS: These results suggested that ß-1,4-GalT-I may play an important role in adhesion of Schwann cells during inflammation.

SSeCKS promotes tumor necrosis factor-alpha autocrine via activating p38 and JNK pathways in Schwann cells.

Tumor necrosis factor-alpha (TNF-alpha) derived from activated Schwann cells (SCs) plays a critical role as an inflammatory mediator in the peripheral nervous system disease. TNF-alpha could act as an autocrine mediator in SC activation. In this study, we found knockdown Src-suppressed protein kinase C substrate (SSeCKS) expression suppressed TNF-alpha production induced by TNF-alpha, overexpression of SSeCKS could promoted TNF-alpha autocrine in SCs. Such effects might be resulted in SSeCKS promoted p38 and JNK activation in SCs treated by TNF-alpha. Thus present data show that while SCs activation, SSeCKS may plays an important role in the release of inflammatory mediators.

SSeCKS is a suppressor in Schwann cell differentiation and myelination.

Src-suppressed protein kinase C substrate (SSeCKS) plays an important role in the differentiation process. In regeneration of sciatic nerve injury, expression of SSeCKS decreases, mainly in Schwann cells. However, the function of SSeCKS in Schwann cells differentiation remains unclear. We observed that SSeCKS was decreased in differentiated Schwann cells. In long-term SSeCKS-reduced Schwann cells, cell morphology changed and myelin gene expression induced by cAMP was accelerated. Myelination was also enhanced in SSeCKS-suppressed Schwann cells co-culture with dorsal root ganglion (DRG). In addition, we found suppression of SSeCKS expression promoted Akt serine 473 phosphorylation in cAMP-treated Schwann cells. In summary, our data indicated that SSeCKS was a negative regulator of myelinating glia differentiation.

Expression of beta-1,4-galactosyltransferase I in rat Schwann cells.

Glycosylation is one of the most important post-translational modifications. It is clear that the single step of beta-1,4-galactosylation is performed by a family of beta-1,4-galactosyltransferases (beta-1,4-GalTs), and that each member of this family may play a distinct role in different tissues and cells. In the present study, real-time PCR revealed that the beta-1,4-GalT I mRNA reached peaks at 2 weeks after sciatic nerve crush and 3 days after sciatic nerve transection. Combined in situ hybridization for beta-1,4-GalT I mRNA and immunohistochemistry for S100 showed that beta-1,4-GalT I mRNAs were mainly located in Schwann cells after sciatic nerve injury. In conclusion, beta-1,4-GalT I might play important roles in Schwann cells during the regeneration and degeneration of the injured sciatic nerve. In other pathology, such as inflammation, we found that LPS administration affected beta-1,4-GalT I mRNA expression in sciatic nerve in a time- and dose-dependent manner, and beta-1,4-GalT I mRNA is expressed mainly in Schwann cells. These results indicated that beta-1,4-GalT I plays an important role in the inflammation reaction induced by intraperitoneal injection of LPS. Similarly, we found that beta-1,4-GalT I in Schwann cells in vitro was affected in a time- and concentration-dependent manner in response to LPS stimulation. All these results suggest that beta-1,4-GalT I play an important role in Schwann cells in vivo and vitro during pathology. In addition, beta-1,4-GalT I production was drastically suppressed by U0126 (ERK inhibitor), SB203580 (p38 inhibitor), or SP600125 (SAPK/JNK inhibitor), which indicated that Schwann cells which regulated beta-1,4-GalT I expression after LPS stimulation were via ERK, SAPK/JNK, and P38 MAP kinase signal pathways.

Tumor necrosis factor-alpha inhibits Schwann cell proliferation by up-regulating Src-suppressed protein kinase C substrate expression.

Src-suppressed protein kinase C substrate (SSeCKS) is a protein kinase C substrate protein, which plays an important role in mitogenic regulatory activity. In the early stage of nerve injury, expression of SSeCKS in the PNS increases, mainly in Schwann cells (SCs). However, the exact function of SSeCKS in the regulation of SC proliferation remains unclear. In this study, we found that tumor necrosis factor-alpha (TNF-alpha) induced both SSeCKS alpha isoform expression and SC growth arrest in a dose-dependent manner. By knocking down SSeCKS alpha isoform expression, TNF-alpha-induced growth arrest in SCs was partially rescued. Concurrently, the expression of cyclin D1 was reduced and the activity of extracellular signal-regulated kinase 1/2 was decreased. A luciferase activity assay showed that cyclin D1 expression was regulated by SSeCKS at the transcription level. In addition, the cell fragments assay and immunofluorescence revealed that TNF-alpha prevented the translocation of cyclin D1 into the nucleus, while knocking down SSeCKS alpha isoform expression prompted cyclin D1 redistribution to the nucleus. In summary, our data indicate that SSeCKS may play a critical role in TNF-alpha-induced SC growth arrest through inhibition of cyclin D1 expression thus preventing its nuclear translocation.

SCY1-Like 1-Binding Protein 1 (SCYL1BP1) Suppressed Sciatic Nerve Regeneration by Enhancing the RhoA Pathway.

SCY1-like 1-binding protein 1 (SCYL1BP1) is first identified as an interacting protein with SCYL1. Since SCYL1BP1 is a soluble protein with coiled-coil domains known to be relevant with transcriptional regulation, it has been found to activate the transcription of murine double minute 2 (MDM2) and participate in neurite outgrowth and regeneration. However, the role and mechanism of SCYL1BP1 in peripheral nerve system lesion and repair are still unknown. Here in vitro, our work demonstrated that SCYL1BP1 inhibited cAMP-induced primary Schwann cell differentiation and suppressed nerve growth factor-mediated neurite outgrowth in PC12 cells by enhancing the RhoA pathway. Furthermore, we found that pretreatment with a Rho kinase inhibitor Y-27632 resulted in partial rescue of Schwann cell differentiation and neurite outgrowth. In vivo experiments showed that SCYL1BP1 could also suppress nerve fiber regeneration. In conclusion, we speculated that SCYL1BP1 participated in Schwann cell (SC) differentiation and neurite outgrowth in the sciatic nerve after crush by regulating the RhoA pathway.

Transcription factor Snai1-1 induces osteosarcoma invasion and metastasis by inhibiting E-cadherin expression.

Osteosarcoma (OS) is a type of primary malignant bone tumor with a high propensity for local recurrence and distant metastasis. A previous study showed Snail-1 is highly expressed in OS cells. The present study aimed to investigate the association between the transcription factor Snai1 and E-cadherin in OS. SaOS2 OS cells were transfected either with a plasmid expressing short hairpin RNA (shRNA) specific for the Snai1-1 gene (SaOS2-shRNA) or a negative control plasmid (SaOS2-Mock). The expression levels of E-cadherin and Snai1-1 in the transfected and control cells were determined by quantitative polymerase chain reaction and western blot analysis. In addition, the study was extended to evaluate the migratory and invasive properties of the cells through a Transwell experiment. The results show that E-cadherin was expressed at a high level in the SaOS2-shRNA cells, which were much less migratory and invasive than the control cells. Overexpression of Snai1-1 in OS is associated with tumor progression, possibly through the suppression of E-cadherin expression and induction of the process of epithelial-mesenchymal transition, which contributes to the proceeding invasion and metastasis of OS cells.

The member of high temperature requirement family HtrA2 participates in neuronal apoptosis after intracerebral hemorrhage in adult rats.

The members of high-temperature requirement (HtrA) family are evolutionarily conserved serine proteases that combine a trypsin-like protease domain with at least one PDZ interaction domain. HtrA2, a special one, is mainly located in mitochondria and required for maintaining homeostasis. Once released into cytoplasm, HtrA2 contributes to apoptosis via caspase-dependent and -independent pathways. Accumulating evidence has showed its pro-apoptotic effect in cancers and central nervous system (CNS) diseases. However, the distribution and function of HtrA2 in CNS diseases remains to be further explored. To investigate HtrA2's roles in the pathophysiology of intracerebral hemorrhage (ICH), an ICH rat model was established and assessed by behavioral tests. Western blot and immunohistochemistry revealed a remarkable up-regulation of HtrA2 surrounding the hematoma after ICH; and immunofluorescence showed HtrA2 was strikingly increased in neurons, but not in astrocytes and oligodendrocytes. Terminal deoxynucleotidyl transferase-mediated biotinylated-dUTP nick-end labeling staining suggested the involvement of HtrA2 in neuronal apoptosis after ICH. Additionally, HtrA2 co-localized with active-caspase-3 around the hematoma and the expression of active-caspase-3 was parallel with that of HtrA2 in a time-dependent manner. Furthermore, hemin was used to stimulus a neuronal cell line PC12 to mimic ICH model in vitro. We analyzed the relationship of HtrA2 with X-linked inhibitor of apoptosis protein (XIAP) in PC12 cells by Western blot, immunofluorescence and co-immunoprecipitation. The connection of HtrA2 with XIAP was strengthened in apoptotic cells after hemin treatment. Thus, we speculated that HtrA2 might exert an important function in regulating caspase-dependent neuronal apoptosis through interacting with XIAP following ICH.

[Influence of the depth of retained denatured dermis on the survival rate of grafted skin in burn swine with deep partial-thickness burn].

OBJECTIVE: To explore the influence of the thickness of retained denatured dermis on the survival rate of grafted skin in swine with deep partial-thickness burn. METHODS: Four deep partial-thickness wounds were reproduced respectively on both sides of spine in 7 Chinese domestic pigs. The wounds of 6 pigs were divided into 0.25, 0.50, 0.75, and 1.00 mm groups with 12 wounds in each group according to the random number table. Tangential excision and auto-skin grafting were performed. Before the tangential excision, 1 tissue specimen was harvested from the center of each remaining wound for the estimation of the depth of burn, and histological observation was done. After the tangential excision, 1 tissue specimen was harvested from the area near the center of each wound for the measurement of the depth of retained denatured dermis with histological examination. The 8 wounds of one pig were set as the control group, and the operation was done, and then they were treated with exposure treatment after biopsy specimens were taken with above-mentioned method. The general condition of wounds in 5 groups was observed from immediately after injury to post injury month (PIM) 3. On post injury day (PID) 7, the survival rate of grafted skin was observed in 0.25, 0.50, 0.75, and 1.00 mm groups. Wound healing time was recorded. At PIM 3, the specimens were harvested from the wounds of 5 groups, and their ultra microstructures were observed by transmission electron microscope. Data were processed with rank-sum test, one-way analysis of variance, and LSD test. RESULTS: The depth of the burn tissue was (1.120 ± 0.211) mm. The depths of retained denatured dermis in 0.25, 0.50, 0.75, and 1.00 mm groups were respectively (0.830 ± 0.031), (0.701 ± 0.010), (0.382 ± 0.031), and (0.141 ± 0.040) mm. At PID 8, all grafted skin in 0.25 and 0.50 mm groups became necrotic; most grafted skin in 0.75 mm group was necrotic; most grafted skin in 1.00 mm group survived with only a few became necrotic and separated from the wounds. The scabs were gradually separated from the wounds of control group. On PID 15, the grafted skin which did not survive in 0.25, 0.50, and 0.75 mm groups was gradually separated from the wounds with exudate forming scab on the surface in varying degrees, while the wounds in 1.00 mm group were all healed, and the incidence of scabs formation was highest in control group. At PIM 3, scar contraction was found in 0.25, 0.50, 0.75 mm groups and control group, while no obvious scar was observed in 1.00 mm group. There were statistically significant differences in the survival rate of grafted skin in 0.25, 0.50, 0.75, and 1.00 mm groups (χ(2) = 19.421, P < 0.001). The survival rate was the highest in 1.00 mm group [70% (60%, 80%)], while the survival rate was 20% (0, 30%) in 0.75 mm group, and it was in both 0.25 and 0.50 mm groups with non-survival of all the grafted skin. There were statistically significant differences in the wound healing time among 5 groups (F = 41.450, P < 0.001). The wound healing time in 0.25 and 0.50 mm groups were respectively (18.2 ± 1.5), and (18.7 ± 2.3) d, not statistically significant different from that of control group [(18.4 ± 1.7) d, P values both above 0.05]. The wound healing time in 0.75 mm group [(14.9 ± 2.6) d] was significantly different from those of 0.25, 0.50 mm groups and control group (P values all below 0.01). The wound healing time in 1.00 mm group [(9.5 ± 1.2) d] was significantly shorter compared with that of the other 4 groups (P values all below 0.01). Before tangential excision, the zone of infiltration of the inflammatory cells was observed in the deep dermis of wounds in 5 groups. After tangential excision and before auto-skin grafting, the depth from the fault surface to the zone of infiltration of the inflammatory cells varied in 0.25, 0.50, 0.75, and 1.00 mm groups while more inflammatory cells were observed in control group. At PIM 3, many fibroblasts were observed in the dermis of wounds in 1.00 mm group with abundant rough endoplasmic reticulum and basically intact organelles. CONCLUSIONS: Performing autologous skin grafting on deep partial-thickness burn, in which the depth of retained denatured dermis was 0.10 mm, may help regenerate dermal function and alleviate scar formation.

[Percutaneous kyphoplasty in hyperextension position for treatment of middle and late period Kümmell disease].

OBJECTIVE: To evaluate the feasibility and effectiveness of percutaneous kyphoplasty in hyperextension position for treatment of stage II or III Kümmell disease. METHODS: Between May 2003 and February 2009, 17 patients with Kümmell disease (6 at stage II, 11 at stage III) were treated with percutaneous kyphoplasty in hyperextension position. There were 5 males and 12 females with an average age of 71 years (range, 55-85 years). The involved vertebral bodies were T10 in 1 case, T11 in 3 cases, T12 in 7 cases, L1 in 4 cases, L2 in 1 case, and T12, L1 in 1 case by X-ray, CT, and MRI examinations. The effectiveness was determined by the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). The height and the kyphotic Cobb angle of the involved vertebral body were measured pre- and postoperatively. RESULTS: The operation was successfully completed in all the patients, and the incisions healed by first intention. Pain was alleviated or eliminated within 48 hours after operation; no spinal nerves injury or pulmonary embolism occurred. One patient had cement leakage to the adjacent disc, who did not manifest any clinical symptoms. Thirteen patients were followed up 24 to 56 months (mean, 32 months). The VAS score, ODI, anterior and medial vertebral height, kyphotic Cobb angle of involved vertebral body were improved significantly at 1 week after operation and at last follow-up (P < 0.05), there was no significant difference between at 1 week after operation and at last follow-up (P > 0.05). Adjacent vertebral fracture occurred in 1 patient at 6 months after operation and was cured after percutaneous kyphoplasty. CONCLUSION: Percutaneous kyphoplasty in hyperextension position for treatment of stage II or III Kümmell disease can relieve back pain, improve viability, decrease Cobb angle, and retain the vertebral body height and spinal alignment. The general condition of the patient is needed to be evaluated and the operation indication should be controlled strictly.

Snail-1 regulates VDR signaling and inhibits 1,25(OH)-D3 action in osteosarcoma.

Previous research has shown that vitamin D could suppress proliferation, migration and invasion of cancers, but the effects of vitamin D may be related to the expression of Snail-1, which could inhibit the expression of the vitamin-D gene receptor (VDR). Snail-1 is overexpressed in osteosarcoma, this study was conducted to determine whether inhibiting Snail-1 could increase the role of vitamin D as an anti- osteosarcoma agent. We used stable transfection of the SaOS2 cell line as in vitro model to study the effect of 1,25(OH)-D3, which is the most active metabolite of vitamin D. The in vitro antiproliferative, pro-apoptotic and inhibiting of invasion effects were examined. The effects of 1,25(OH)-D3 on the expression of ß-catenin signaling pathways were also studied. Then in vivo antiproliferative effect of 1,25(OH)-D3 was also detected in nude mice injected with either mock-infected or Snail-1 SaOS2 cells. We found that inhibition of Snail-1 signaling by transfection could increase the expression of VDR, enhance the anti-proliferative activity of 1,25(OH)-D3 in osteosarcoma cells, and induce apoptosis and lower invasion in vitro. The effect of 1,25(OH)-D3 was also associated with decreased expression of ß-catenin signaling, which is related to VDR signaling. In vivo, the effect of antiproliferative was higher in mice injected with either Snail-1-infected cells than with mock-infected cells. Our findings suggest that canonical Snail-1/VDR/ß-catenin signaling reflects an important underlying mechanism of osteosarcoma progression. Therefore, strategies to suppress Snail-mediated signaling may lead to the better action of 1,25(OH)-D3 as an anti osteosarcoma treatment.

A prospective clinical study of proximal humerus fractures treated with a locking proximal humerus plate.

OBJECTIVES: The purpose of this prospective study was to evaluate the safety, efficacy, and functional outcome of the locked proximal humerus plate (LPHP) to treat proximal humerus fractures. DESIGN: Prospective clinical trial. SETTING: University orthopedic center. PATIENTS: Over a 25-month period, 64 consecutive patients were treated with a LPHP for an unstable or displaced proximal humerus fracture. INTERVENTION: Demographic data, trauma mechanisms, surgical approaches, and postoperative complications were collected from medical records. Fracture classification according to the Neer classification, radiographic head-shaft angle, and screw tip-articular surface distance in true anteroposterior and axillary lateral radiographs of the shoulder were measured postoperatively. MAIN OUTCOME MEASUREMENTS: The functional outcome was evaluated with a Constant-Murley (CM) evaluation. The CM score is a validated shoulder-specific scoring system in which patients report subjective findings. The physician reported the objective measurements of the shoulder. RESULTS: Follow-ups were completed for all of the patients. The overall complication rate was 35.9%, with screw penetration into the glenohumeral joint as the most frequent problem (7.6%). Deep wound infections were observed in 3.1% (n = 2) of the cases and avascular necrosis in 3.1% (n = 2). All complications occurred in 4-part fractures. Subacromial impingement, frozen shoulder, rotator cuff rupture, and wound dehiscence were observed in 3.1% (n = 2), 3.1% (n = 2), 1.6% (n = 1), and 1.6% (n = 1) of the cases, respectively. Multivariate linear regression analysis revealed that the fracture pattern and the presence or absence of medial support were significant predictors of functional outcome (P = 0.026 and P = 0.003, respectively). Patient age (P = 0.581), sex (P = 0.325), and initial tuberosity displacement (varus/extension or valgus/impaction; P = 0.059) were not significantly associated with the CM score. CONCLUSIONS: The LPHP seems to be a promising implant for the fixation of proximal humerus fractures. However, there are certain limitations that should be mentioned. The number of cases in our study was small, and no safe conclusions can be extracted regarding the rate of avascular necrosis. Additional studies with larger cohorts and longer follow-ups are necessary to better define the appropriate indications for and expected outcomes of this technology.

The cyclin-dependent kinase inhibitor p27(Kip1) is a positive regulator of Schwann cell differentiation in vitro.

Schwann cell precursors differentiating into a myelinating phenotype are critical for peripheral nerve development and regeneration. However, little is known about the underlying molecular mechanisms of Schwann cell differentiation. In the present study, we performed a cyclic adenosine monophosphate-induced Schwann cell differentiation model in vitro. Western blot analysis showed that p27(Kip1) expression was upregulated during the differentiation of Schwann cell, while the inhibition of p27(Kip1) expression by short hairpin RNA-mediated knockdown significantly abolished the expression of promyelinating markers and the alteration of cellular morphology. In addition, immunofluorescence revealed a decrease of p27(Kip1) nuclear staining and a concomitant increase of cytoplasmic staining in differentiated Schwann cells. In summary, our data indicated that p27(Kip1) was a positive regulator of Schwann cell differentiation in vitro.