Lihai Zhang

Inhibition of γ-secretase activity reduces Aβ production, reduces oxidative stress, increases mitochondrial activity and leads to reduced vulnerability to apoptosis : Implications for the treatment of Alzheimer's disease

It has been argued that gamma-secretase should be considered as a pharmacological target, as there are few mechanism-based experimental and clinical studies on gamma-secretase treatment. In this study, we found that N2a cells bearing APP695 or its Swedish mutant exhibited increased basal levels of ROS, nitric oxide (NO), protein carbonyls, MDA and intracellular calcium, as well as reduced level of the mitochondrial membrane potential and ATP. When the activity of gamma-secretase was inhibited by expression of the D385A PS1 variant, cells (N2a/Swe.D385A) showed reduced basal levels of ROS, nitric oxide (NO), protein carbonyls, MDA and intracellular calcium, as well as increased mitochondrial membrane potential and ATP level. In addition, N2a/Swe.D385A cells showed reduced vulnerability to H(2)O(2)-induced apoptosis. The Bcl-2 and JNK/ERK pathways were proven to be involved in the change of vulnerability to H(2)O(2)-induced apoptosis. Moreover, we discovered that inhibition of gamma-secretase by DAPT would lead to a reduction of ROS levels and stabilization of mitochondrial function in APP (N2a/APP695) and APP Swedish mutant (N2a/APPswe) transfected cells. At last, it was shown that Abeta antibody and antiserum prevented increase of ROS and reduction of mitochondrial membrane potential in N2a/Swe.DeltaE9 cells but not in N2a/Swe.D385A cells, which indicated that reduced formation of Abeta was the reason for reduction of ROS formation and increase of mitochondrial membrane potential when PS-1 activity was impaired in N2a/Swe.D385A cells. We concluded that neurotoxicity was positively correlated with the activity of gamma-secretase, which suggested inhibition of gamma-secretase is a rational pharmacological target for Alzheimers disease treatment.

Erratum to: Autophagy Reduces Neuronal Damage and Promotes Locomotor Recovery via Inhibition of Apoptosis after Spinal Cord Injury in Rats

Autophagy is an intracellular catabolic mechanism that maintains the balance of proteins, lipids and aging organelles. 3-Methyladenine (3-MA) is a selective inhibitor of autophagy, whereas rapamycin, an antifungal agent, is a specific inducer of autophagy, inhibiting the protein mammalian target of rapamycin. In the present study, we examined the role of autophagy, inhibited by 3-MA and enhanced by rapamycin, in a model of acute spinal cord injury in rats. We found that rapamycin could significantly increase the expression of microtubule-associated protein 1 light chain 3 (LC3) and Beclin1 at the injury site. At the same time, the number of neurons and astrocytes with LC3 positive in the spinal cord was upregulated with time. In addition, administration of rapamycin produced an increase in the Basso, Beattie and Bresnahan scores of injured rats, indicating high recovery of locomotor function. Furthermore, expression of the proteins Bcl-2 and Bax was upregulated and downregulated, respectively. By contrast, the results for rats treated with 3-MA, which inhibits autophagy, were the opposite of those seen with the rapamycin-treated rats. These results show that induction of autophagy can produce neuroprotective effects in acute spinal cord injury in rats via inhibition of apoptosis.

Schwann-like cell differentiation of rat adipose-derived stem cells by indirect co-culture with Schwann cells in vitro

Objectives:  Schwann cell (SC) transplantation is a promising therapy for peripheral nerve transaction, however, clinical use of SCs is limited due to their very limited availability. Adipose‐derived stem cells (ADSCs) have been identified as an alternative source of adult stem cells in recent years. The aim of this study was to evaluate the feasibility of using ADSCs as a source of stem cells for differentiation into Schwann‐like cells by an indirect co‐culture approach, in vitro.

Proximal femoral nail antirotation versus hemiarthroplasty: A study for the treatment of intertrochanteric fractures

Intertrochanteric fractures in elderly patients are always associated with poor prognosis in the functional outcome as a result of the complications and mortality. A retrospective study was performed in our institution, 303 consecutive patients were followed up with mean age of 81.7 years. 147 were treated with PFNA, and 156 were underwent hemiarthroplasty. The average follow-up period was 39.9 months. The mortality at 1 month, 1 year, 3 years and the total was 6.6%, 18.6%, 27.6% and 30.3%, respectively. There were no significant differences between the groups in terms of demographic data. There were statistical significances in the operative statistics, especially the anaesthesia, operation lasting time, blood loss, blood transfusion and the drainage. There was no significant difference in Harris Hip Score between PFNA and hemiarthroplasty group, but the detail items were quite different. Significant difference was found in the excellent-to-fine rate (PFNA 90.2% and hemiarthroplasty 79.6%). Complications occurred in 34 patients, although incidences of complications were higher in hemiarthroplasty group (14.1% vs. PFNA 8.96%), no statistical difference was found. For elderly patients with intertrochanteric fractures, PFNA was superior to hemiarthroplasty according to the operative statistics, but there were no significant differences in functional outcome.

The Association of GSK3β with E2F1 Facilitates Nerve Growth Factor-induced Neural Cell Differentiation

It is widely acknowledged that E2F1 and GSK3β are both involved in the process of cell differentiation. However, the relationship between E2F1 and GSK3β in cell differentiation has yet to be discovered. Here, we provide evidence that in the differentiation of PC12 cells induced by nerve growth factor (NGF), GSK3β was increased at both the mRNA and protein levels, whereas E2F1 at these two levels was decreased. Both wild-type GSK3β and its kinase-defective mutant GSK3β KM can inhibit E2F1 by promoting its ubiquitination through physical interaction. In addition, the colocalization of GSK3β and E2F1 and their subcellular distribution, regulated by NGF, were observed in the process of PC12 differentiation. At the tissue level, GSK3β colocalized and interacted with E2F1 in mouse hippocampus. Furthermore, GSK3β facilitated neurite outgrowth by rescuing the promoter activities of Cdk inhibitors p21 and p15 from the inhibition caused by E2F1. To summarize, our findings suggest that GSK3β can promote the ubiquitination of E2F1 via physical interaction and thus inhibit its transcription activity in a kinase activity independent manner, which plays an important role in the NGF-induced PC12 differentiation.

Effect of Single-Injection versus Continuous Local Infiltration Analgesia after Total Knee Arthroplasty: A Randomized, Double-Blind, Placebo-Controlled Study

In this randomized, double-blind, placebo-controlled, single-centre study, 80 patients (American Society of Anesthesiologists physical status I — III) received postoperative single-injection local infiltration analgesia (SLIA), continuous local infiltration analgesia (CLIA) or placebo (control group). Intravenous patient-controlled morphine was used as rescue analgesia. The CLIA group showed lower postoperative visual analogue scale (VAS) pain scores from 8 to 48 h at rest and from 16 to 48 h during activity compared with the SLIA group. The CLIA group also had significantly lower consumption of morphine from 24 to 48 h postoperatively versus the SLIA group. Patient satisfaction was higher, and maximum flexion of the knee on postoperative days 7 and 90 was greater, in the CLIA group compared with the SLIA group. CLIA provided prolonged superior analgesia and was associated with more favourable functional recovery and patient satisfaction compared with SLIA.

Huperzine A promotes hippocampal neurogenesis in vitro and in vivo.

Huperzine A (Hup A) is a lycopodium alkaloid from Huperzia serrata, which has been used as a therapeutic agent in several neurological disorders. Despite the diverse pharmacological activities Hup A has, its role in hippocampal neurogenesis remains to be established. This study showed that Hup A not only promoted the proliferation of cultured mouse embryonic hippocampal neural stem cells (NSCs), but also increased the newly generated cells in the subgranular zone (SGZ) of the hippocampus in adult mice. Furthermore, the in vitro findings indicated that low concentrations of Hup A stimulated the proliferation of cultured NSCs, whereas extremely high concentration of it decreased the cell proliferation. Hup A activated mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway, which was a well-known regulator of biological processes including cell proliferation and differentiation. ERK inhibitor dramatically inhibited the proliferative effect of Hup A on NSCs. Administration of Hup A to adult mice significantly enhanced the cell proliferation in dentate gyrus of hippocampus, and increased the remaining newborn cells 4 weeks after the drug administration. Moreover, the newly generated BrdU(+)/NeuN(+) neurons were also increased by Hup A treatment. These findings suggest a novel role of Hup A in neurogenesis and provide a new insight into its therapeutic effects in neurological disorders via a neurogenesis-related mechanism.

Synthesis and Properties of Hemostatic and Bacteria-Responsive in Situ Hydrogels for Emergency Treatment in Critical Situations

Immediate hemorrhage control and infection prevention are pivotal for saving lives in critical situations such as battlefields, natural disasters, traffic accidents, and so on. In situ hydrogels are promising candidates, but their mechanical strength is often not strong enough for use in critical situations. In this study, we constructed three hydrogels with different amounts of Schiff-base moieties from 4-arm-PEG-NH2, 4-arm-PEG-NHS, and 4-arm-PEG-CHO in which vancomycin was incorporated as an antimicrobial agent. The hydrogels possess porous structures, excellent mechanical strength, and high swelling ratio. The cytotoxicity studies indicated that the composite hydrogel systems possess good biocompatibility. The Schiff bases incorporated improve the adhesiveness and endow the hydrogels with bacteria-sensitivity. The in vivo hemostatic and antimicrobial experiments on rabbits and pigs demonstrated that the hydrogels are able to aid in rapid hemorrhage control and infection prevention. In summary, vancomycin-loaded hydrogels may be excellent candidates as hemostatic and antibacterial materials for first aid treatment of the wounded in critical situations.

Protective effect of edaravone against Alzheimer's disease-relevant insults in neuroblastoma N2a cells

Oxidative stress has been demonstrated to be involved in the pathogenesis of Alzheimers disease (AD). Thus, antioxidant therapy may represent a promising avenue for the treatment of AD. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a potent free radical scavenger and has been shown to provide neuroprotection in both animal models of cerebral ischemia and stroke patients. In the present study, we investigated the protective effect of edaravone against AD-relevant insults in neuroblastoma N2a cells and explored the potential mechanisms involved. N2a/Swe.Δ9 cells were used as the AD model cells, which exhibited reduced cell viability, increased apoptosis and oxidative stress as well as decreased mitochondrial membrane potential compared with N2a/Wt cells. All of these phenotypes were significantly reversed by edaravone treatment. Edaravone treatment significantly elevated cell viability, reduced apoptotic rate, attenuated oxidative stress and improved mitochondrial membrane potential in N2a/Swe.Δ9 cells. Furthermore, edaravone treatment inhibited mitochondria-dependent apoptosis pathways in N2a/Swe.Δ9 cells through decreasing the Bax/Bcl-2 ratio, attenuating cytochrome c release and suppressing the activation of caspase-3. These results demonstrate that edaravone provides neuroprotection in an AD-related in vitro model and therefore, may be a potential complement for AD therapy.

Novel 3D hexapod computer-assisted orthopaedic surgery system for closed diaphyseal fracture reduction

Long‐bone fractures are very common in trauma centers. The conventional Arbeitsgemeindschaft fur Osteosynthesefragen (AO) technique contributes to most fracture healing problems, and external fixation technology also has several disadvantages, so new techniques are being explored.