Low-energy shock waves promote the cisplatin chemosensitivity of human osteosarcoma MNNG/HOS cells via the P2X7/Akt/mTOR pathway.

Background: The current dilemma of osteosarcoma treatment is the resistance of chemotherapeutic drugs after long-term usage, which also introduces life-threatening side effects. Methods and results: To minimize chemoresistance in osteosarcoma patients, the authors applied shock waves (SWs) to human osteosarcoma MNNG/HOS cells, then evaluated the cell viability and extracellular ATP levels, and further investigated the effect of SWs on cisplatin (DDP) cytotoxicity in MNNG/HOS cells. The authors' results showed that 400 SW pulses at 0.21 mJ/mm2 exhibited little influence on the MNNG/HOS cell viability. In addition, this SW condition significantly promoted the extracellular ATP release in MNNG/HOS cells. Importantly, low-energy SWs obviously increased Akt and mammalian target of rapamycin (mTOR) phosphorylation and activation in MNNG/HOS cells, which could be partially reversed in the presence of P2X7 siRNA. The authors also found that low-energy SWs strongly increased the DDP sensitivity of MNNG/HOS cells in the absence of P2X7. Conclusions: For the first time, the authors found that SW therapy reduced the DDP resistance of MNNG/HOS osteosarcoma cells when the ATP receptor P2X7 was downregulated. SW therapy may provide a novel treatment strategy for chemoresistant human osteosarcoma.

A novel treatment of clavicular nonunion: Combination with PRP, autologous bone grafting, and internal plate fixation.

BACKGROUND: Nonunion is a major concern for orthopedic surgeons, particularly nonunion of the clavicle, which can cause severe pain, loss of full range of motion, poor sleep quality, and loss of strength in the affected individuals. Platelet-rich plasma (PRP), an important biological agent, is widely used in orthopedics. OBJECTIVE: We used a combination of three techniques - the PRP technique, autologous bone grafting technique, and internal plate fixation technique - to ensure adequate internal fixation and enable a bone growth-supportive environment at the fracture site. METHODS: The surgical approach was applied to a patient with clavicle nonunion. RESULTS: Based on postoperative follow-up findings and intraoperative findings at the time of re-removal of the patient's implant, the prognosis at the fracture site was considered satisfactory. CONCLUSION: We observed that the patient treated with this method had favorable clinical outcomes, and we recommend that this technique be used in patients with long-bone nonunion.

Incidence, distribution, disease spectrum, and genetic deficits of congenital heart defects in China: implementation of prenatal ultrasound screening identified 18,171 affected fetuses from 2,452,249 pregnancies.

BACKGROUND: Congenital heart defects (CHDs) are the most common birth defects. Assessment of the incidence, distribution, disease spectrum, and genetic deficits of fetal CHDs in China is urgently needed. METHODS: A national echocardiography screening program for fetal CHDs was implemented in 92 prenatal screening-diagnostic centers in China. FINDINGS: A total of 18,171 fetal CHD cases were identified from 2,452,249 pregnancies, resulting in 7·4/1,000 as the national incidence rate of fetal CHD. The incidences of fetal CHD in the six geographical regions, the southern, central, eastern, southwestern, northern, and northwestern, were 7·647 (CI: 7·383-7·915), 7·839 (CI: 7·680-8·000), 7·647 (CI: 7·383-7·915), 7·562 (CI: 7·225-7·907), 5·618 (CI: 5·337-5·906), and 4·716 (CI: 4·341-5·108), respectively, per 1,000 pregnancies. Overall, ventricular septal defect was the most common fetal CHD, accounting for 17.04% of screened pregnancies nationwide, and tetralogy of Fallot, the most common anomaly in the major defect of fetal CHD, was the second most common, accounting for 9.72%. A total of 76.24% cases of fetal CHD were found to be an isolated intracardiac single defect. The remaining 23.76% of cases of fetal CHD had multiple heart defects. Among all extracardiac malformations, the central nervous system (CNS) was the most common tissue with extracardiac anomalies associated with CHD, accounting for 22.89% of fetal CHD cases. Chromosomal karyotyping identified trisomy 18 as the most common chromosomal abnormality in fetal CHD. We also documented that CHD-containing syndromes could be identified with a comprehensive approach integrating prenatal ultrasound, MRI, pathological autopsy, and cytogenetics and molecular genetics. CONCLUSION: Implementation of prenatal echocardiography as a practically feasible platform to screen fetal CHD will reduce the financial and emotional burden of CHD, which may facilitate intrauterine and neonatal intervention of CHD.

Characterization of placental and decidual cell development in early pregnancy loss by single-cell RNA sequencing.

BACKGROUND: Early pregnancy loss (EPL) presents as sporadic or recurrent miscarriage during the first trimester. In addition to chromosomal defects, EPL may result from impairment of the placental-decidual interface at early gestational age due to gene-environmental interactions. METHODS: To better understand the pathogenesis associated with this impairment, cell development in chorionic villi and decidua of different forms of EPL (sporadic or recurrent) was investigated with single-cell RNA sequencing and compared to that of normal first-trimester tissue. RESULTS: Unique gene expression signatures were obtained for the different forms of EPL and for normal tissue and the composition of placental and decidual cell clusters in each form was established. In particular, the involvement of macrophages in the EPL phenotypes was identified revealing an immunoactive state. CONCLUSION: Differential gene expression and unique marker genes among cell clusters from chorionic villi and decidua of miscarried and normal pregnancies, may lead to identification of biomarker for EPL.

Reduced expression in preterm birth of sFLT-1 and PlGF with a high sFLT-1/PlGF ratio in extracellular vesicles suggests a potential biomarker.

Preterm birth may have a pathological impact on intrauterine development of the fetal brain, resulting in developmental disabilities. In this study, we examine the expression of soluble Fms-like tyrosine kinase 1 (sFLT-1) and placental growth factor (PlGF), which is one of the vascular endothelial growth factors (VEGFs), as these play a key role in angiogenesis; in particular, we examine their effect on the sFLT-1/PlGF ratio in cases of preterm birth as compared to typical pregnancies. Enzyme-linked immunosorbent assay was performed on samples of maternal-derived plasma and extracellular vesicles-exosomes (EVs-EXs) isolated at the third trimester, consisting of 17 samples from cases of preterm birth and 38 control cases. Our results showed that both sFLT-1 (P=0.0014) and PlGF (P=0.0032) were significantly downregulated in cases of preterm birth compared to controls, while the sFLT-1/PIGF ratio was significantly (P=0.0008) increased in EVs-EXs, but not in maternal plasma. Our results suggest that this reduced expression of sFLT-1 and PlGF with an elevated sFLT-1/PlGF ratio in EVs-EXs may represent a potential biomarker for prediction of PTB.

Functional outcomes and adverse effects following three interventions for displaced midshaft clavicular fractures: A Bayesian network meta-analysis of randomized controlled trials.

INTRODUCTION: The efficacy of the most commonly used interventions for clavicle fractures remains controversial. These interventions are: open reduction and plate fixation (ORPF), non-surgical intervention (NSI), and use of an intramedullary nail (IMN). In adult patients with clavicle fractures, choosing which intervention might be best is challenging. MATERIALS AND METHODS: PubMed, Journals@Ovid Full Text, Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, and Embase were performed to search English-language studies from the inception to February 2020. Randomized controlled trials (RCTs) comparing any of these three interventions were included. Patient and baseline characteristics, nonunion, major complications, Constant-Murley score (CMS), and Disabilities of the Arm, Shoulder and Hand score (DASH) were extracted. Then, we evaluated the functional outcomes and adverse effects after use of these three interventions for the management of displaced midshaft clavicle fractures in a Bayesian network meta-analysis. RESULTS: A Bayesian random-effects model was conducted, and nonunion and major complications were evaluated with: risk ratio (RR) and 95% confidential interval (CI); while CMS and DASH were evaluated with mean differences (MD) and the corresponding 95% confidential interval CI. The rank probability of each endpoint was assessed on the basis of the surface area under the cumulative ranking curve (SUCRA). DISCUSSION: ORPF is most likely to be successful in achieving objective functional outcomes as captured by the CMS, and IMN demonstrates significant efficacy for subjective functional outcomes, as captured by DASH scores. Compared with the other interventions examined, IMN was associated with decreased risk for adverse effects. LEVELS OF EVIDENCE: I; meta-analysis.

Transcriptomics-determined chemokine-cytokine pathway presents a common pathogenic mechanism in pregnancy loss and spontaneous preterm birth.

PROBLEM: Various etiological factors, such as infection and inflammation, may induce the adverse outcomes of pregnancy of miscarriage, stillbirth, or preterm birth. The pathogenic mechanisms associated with these adverse pregnancies are yet unclear. We hypothesized that a common pathogenic mechanism may underlie variant adverse outcomes of pregnancy, which are induced by genetic-environmental factors. The specific objective of the current study is to uncover the common molecular mechanism(s) by identifying the specific transcripts that are present in variant subtypes of pregnancy loss and preterm birth. METHOD OF STUDY: Transcriptomic profiling was performed with RNA expression microarray or RNA sequencing of placentas derived from pregnancy loss (which includes spontaneous miscarriage, recurrent miscarriage, and stillbirth) and spontaneous preterm birth, followed by bioinformatic analysis of multi-omic integration to identify pathogenic molecules and pathways involved in pathological pregnancies. RESULTS: The enrichment of common differentially expressed genes between full-term birth and preterm birth and pregnancy loss of miscarriage and stillbirth revealed different pathophysiological pathway(s), including cytokine signaling dysregulated in spontaneous preterm birth, defense response, graft-versus-host disease, antigen processing and presentation, and T help cell differentiation in spontaneous miscarriage. Thirty-three genes shared between spontaneous preterm birth and spontaneous miscarriage were engaged in pathways of interferon gamma-mediated signaling and of antigen processing and presentation. For spontaneous miscarriage, immune response was enriched in the fetal tissue of chorionic villi and in the maternal facet of the placental sac. The transcript of nerve growth factor receptor was identified as the common molecule that is differentially expressed in all adverse pregnancies: spontaneous preterm birth, stillbirth, spontaneous miscarriage, and recurrent miscarriage. Superoxide dismutase 2 was up-regulated in all adverse outcomes of pregnancy except for recurrent miscarriage. Cytokine-cytokine receptor interaction was the common pathway in spontaneous preterm birth and spontaneous miscarriage. Defense response was enriched in the fetal tissue of miscarriage and in the maternal tissue in spontaneous miscarriage. CONCLUSIONS: Our results indicated that the chemokine-cytokine pathway may play important roles in and function as a common pathogenic mechanism associated with, the different adverse outcomes of pregnancy, which demonstrated that differentially expressed transcripts could result from a common pathogenic mechanism associated with pregnancy loss and spontaneous preterm birth, although individual pregnancy outcomes may differ from each other phenotypically.

(Epi)genetic variants of the sarcomere-desmosome are associated with premature utero-contraction in spontaneous preterm labor.

Spontaneous preterm birth is a syndrome with clinical and genetic heterogeneity. Few studies have focused on the genetic and epigenetic defects and pathogenic mechanisms associated with premature uterine contraction in spontaneous preterm birth. The objective of this study was to investigate the (epi)genetic variations associated with premature uterine contraction of spontaneous preterm birth. A systems biology approach with an integrated multiomic study was employed. Biobanked pregnancy tissues selected from a pregnancy cohort were subjected to genomic, transcriptomic, methylomic, and proteomic studies, with a focus on genetic loci/genes related to uterine muscle contraction, specifically, genes associated with sarcomeres and desmosomes. Thirteen single nucleotide variations and pathogenic variants were identified in the sarcomere gene, TTN, which encodes the protein Titin, from 146 women with spontaneous preterm labor. Differential expression profiles of five long non-coding RNAs were identified from loci that overlap with four sarcomeric genes. Longitudinally, the long non-coding RNA of gene TPM3 that encodes the protein tropomysin 3 was found to significantly regulate the mRNA of TPM3 in the placenta, compared to maternal blood. The majority of genome methylation profiles related to premature uterine contraction were also identified in the CpG promoters of sarcomeric genes/loci. Differential expression profiles of mRNAs associated with premature uterine contraction showed 22 genes associated with sarcomeres and three with desmosomes. The results demonstrated that premature uterine contraction was associated mainly with pathogenic variants of the TTN gene and with transcriptomic variations of sarcomeric premature uterine contraction genes. This association is likely regulated by epigenetic factors, including methylation and long non-coding RNAs.

Staged treatment and internal fixation of floating ankle: A case report and literature review.

RATIONALE: Floating ankle is a rare traumatic condition characterized by a combination of tibial and ipsilateral foot fractures, with the ankle remaining intact. It is usually caused by high-energy trauma and also presents with serious soft tissue damage. Its treatment is mainly restricted to external fixation, which results in poor outcomes. We present a patient with a floating ankle who underwent staged treatment and achieved full internal fixation, subsequently returning to normal activity. PATIENT CONCERNS: A 26 year- old man had an accident with an reel machine and sustained an open fracture on his right lower extremity. DIAGNOSES: Digital radiograph demonstrated a distal tibial fracture, fibular fracture, and multiple metatarsal fractures, which fulfilled the criteria for a floating ankle. INTERVENTIONS: Initial ankle-spanning external fixation was performed. After 21 days, the patient underwent open reduction and internal fixation on his first and fifth metatarsals, and K-wire fixation on his fourth metatarsal. The external fixator was replaced by plaster fixation. Seven days later, the patient underwent internal fixation of his leg, open reduction and internal fixation with plating was applied of the fibular fracture, and minimally invasive plate osteosynthesis of the tibial fracture. OUTCOMES: At 1-year follow-up, bone union was identified by digital radiograph; after 2 years, his ankle function had fully recovered, and he resumed his normal activities. LESSONS: In the staged treatment protocol of the floating ankle, temporary external fixation provided traction and immobilization of the skeletal and soft tissues. Secondary internal fixation maintained the reduction and alignment and allowed early exercise, which is critical to the prognosis of a floating ankle.

Comparison of plate fixation vs. intramedullary fixation for the management of mid-shaft clavicle fractures: A systematic review and meta-analysis of randomised controlled trials.

A number of meta-analyses have compared clinical outcomes following plate vs. intramedullary fixation for midshaft clavicle fractures (MSCF), but with conflicting results. There is a requirement for updated level-1 evidence to guide clinicians managing MSCF. The aim of the present systematic review and meta-analysis was to compare clinical outcomes following plate vs. intramedullary fixation of MSCF. The PubMed, Scopus, BioMed Central, Cochrane Central Register of Controlled Trials and Google Scholar databases were searched for records added until 1st July 2019. A total of 10 randomised controlled trials (RCTs) were included. Shoulder function was assessed using the Constant-Murley Shoulder Outcome questionnaire and the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). There was no statistically significant difference in Constant-Murley scores between plate and intramedullary fixation [Mean difference (MD)=0.75; 95% CI: -2.49 to 3.99; P=0.65; I2=85%]. Similarly, there was no statistically significant difference in DASH scores between the two groups (MD=1.55; 95% CI: -1.12 to 4.23; P=0.26; I2=89%). There was no statistically significant difference in complications requiring non-routine surgery between plate and intramedullary fixation [risk ratio (RR)=1.80, 95%CI: 0.80-4.05, P=0.15; I2=0%]. There was an increased risk of complications that did not require non-routine surgery with plate fixation as compared to intramedullary fixation (RR=2.38, 95%CI: 1.22-4.62, P=0.01; I2=70%). Plate fixation was also associated with an increased risk of infection and complications of cosmetic dissatisfaction. The present results indicated no difference in long-term functional outcomes between plate and intramedullary fixation of MSCF. Plate fixation was associated with an increased risk of complications not requiring non-routine surgery. Further high-quality RCTs shall strengthen the evidence on this subject.

Nasal delivery of a CRMP2-derived CBD3 adenovirus improves cognitive function and pathology in APP/PS1 transgenic mice.

Calcium dysregulation is a key pathological event in Alzheimer's disease (AD). In studying approaches to mitigate this calcium overload, we identified the collapsin response mediator protein 2 (CRMP2), an axonal guidance protein that participates in synapse dynamics by interacting with and regulating activity of N-methyl-D-aspartate receptors (NMDARs). We further identified a 15 amino acid peptide from CRMP2 (designated CBD3, for calcium-binding domain 3), that reduced NMDAR-mediated Ca2+ influx in cultured neurons and post-synaptic NMDAR-mediated currents in cortical slices. Whether targeting CRMP2 could be therapeutically beneficial in AD is unknown. Here, using CBD3, we tested the utility of this approach. Employing the APP/PS1 mouse model of AD which demonstrates robust pathophysiology including Aß1-42 deposition, altered tau levels, and diminished cognitive functions, we asked if overexpression of CBD3 could rescue these events. CBD3 was engineered into an adeno-associated vector and nasally delivered into APP/PS1 mice and then biochemical (immunohistochemistry, immunoblotting), cellular (TUNEL apoptosis assays), and behavioral (Morris water maze test) assessments were performed. APP/PS1 mice administered adeno-associated virus (AAV, serotype 2) harboring CBD3 demonstrated: (i) reduced levels of Aß1-42 and phosphorylated-tau (a marker of AD progression), (ii) reduced apoptosis in the hippocampus, and (iii) reduced cognitive decline compared with APP/PS1 mice or APP/PS1 administered a control virus. These results provide an instructive example of utilizing a peptide-based approach to unravel protein-protein interactions that are necessary for AD pathology and demonstrate the therapeutic potential of CRMP2 as a novel protein player in AD.

Application of Iron Oxide Nanoparticles in the Diagnosis and Treatment of Neurodegenerative Diseases With Emphasis on Alzheimer's Disease.

Neurodegenerative diseases are characterized by chronic progressive degeneration of the structure and function of the nervous system, which brings an enormous burden on patients, their families, and society. It is difficult to make early diagnosis, resulting from the insidious onset and progressive development of neurodegenerative diseases. The drugs on the market cannot cross the blood-brain barrier (BBB) effectively, which leads to unfavorable prognosis and less effective treatments. Therefore, there is an urgent demand to develop a novel detection method and therapeutic strategies. Recently, nanomedicine has aroused considerable attention for diagnosis and therapy of central nervous system (CNS) diseases. Nanoparticles integrate targeting, imaging, and therapy in one system and facilitate the entry of drug molecules across the blood-brain barrier, offering new hope to patients. In this review, we summarize the application of iron oxide nanoparticles (IONPs) in the diagnosis and treatment of neurodegenerative disease, including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). We focus on IONPs as magnetic resonance imaging (MRI) contrast agents (CAs) and drug carriers in AD. What most neurodegenerative diseases have in common is that hall marker lesions are represented by protein aggregates (Soto and Pritzkow, 2018). These diseases are of unknown etiology and unfavorable prognosis, and the treatments toward them are less effective (Soto and Pritzkow, 2018). Such diseases usually develop in aged people, and early clinical manifestations are atypical, resulting in difficulty in early diagnosis. Recently, nanomedicine has aroused considerable attention for therapy and diagnosis of CNS diseases because it integrates targeting, imaging, and therapy in one system (Gupta et al., 2019). In this review article, we first introduce the neurodegenerative diseases and commonly used MRI CAs. Then we review the application of IONPs in the diagnosis and treatment of neurodegenerative diseases with the purpose of assisting early theranostics (therapy and diagnosis).

Modified tension band wiring of patellar fracture as a technique to minimize postoperative complications: A case report.

RATIONALE: Tension band wiring is the most widely accepted technique for the treatment of patellar fractures but the technique is associated with common complications like wire migration, prominence, and breakage. To reduce these complications, we developed and propose a modified technique that has a superior biomechanical strength and a potential to reduce such postoperative complications. PATIENT CONCERNS: The patient presented with pain and mild swelling in his left knee after he slipped on the floor and fell on his left knee. He has no significant past medical or surgical history. The patient took the tension band wiring as the first choice because of the wide acceptance. But he worried about the complications. DIAGNOSES: X-ray showed a transverse fracture of the left patella with an inferior pole occult fracture. INTERVENTIONS: The patient was operated with a modified technique of the classic tension band wiring for patellar fractures. In our 4-step procedure, double tension cerclage wires were wrapped under the exposed ends of the Kirschner wires (K-wires) and the tendons in figure-of-8 fashion. The aim was to increase the biomechanical strength so that when one of the tension wires fail, the other one can hold the fragments together. OUTCOMES: The patient recovered very well and without any complications. The patient was followed-up for 1 year and the fracture has united very well, with satisfying knee range of motion. LESSONS: From this case study, we can detect the biomechanical advantages of our technique which can increase the stability of the fracture and that allows early functional exercise and additionally the micromotion at the fracture site has a beneficial effect of fracture union. Based on the perfect outcomes, our technique is worthy of clinical application.

Genetic and Expression Analysis of COPI Genes and Alzheimer's Disease Susceptibility.

Alzheimer's disease (AD) is the most common neurodegenerative disease in the elderly and the leading cause of dementia in humans. Evidence shows that cellular trafficking and recycling machineries are associated with AD risk. A recent study found that the coat protein complex I (COPI)-dependent trafficking in vivo could significantly reduce amyloid plaques in the cortex and hippocampus of neurological in the AD mouse models and identified 12 single-nucleotide polymorphisms in COPI genes to be significantly associated with increased AD risk using 6,795 samples. Here, we used a large-scale GWAS dataset to investigate the potential association between the COPI genes and AD susceptibility by both SNP and gene-based tests. The results showed that only rs9898218 was associated with AD risk with P = 0.017. We further conducted an expression quantitative trait loci (eQTLs) analysis and found that rs9898218 G allele was associated with increased COPZ2 expression in cerebellar cortex with P = 0.0184. Importantly, the eQTLs analysis in whole blood further indicated that 11 of these 12 genetic variants could significantly regulate the expression of COPI genes. Hence, these findings may contribute to understand the association between COPI genes and AD susceptibility.

Diffuse large B-cell lymphoma involving peripheral nervous system with IgM antibodies against GM1 and GD1b: A case report.

RATIONALE: The occurrence of peripheral neuropathy associated with non-Hodgkin's lymphoma (NHL) is uncommon. And autoimmunity may play an important role. We report a case of the patient with NHL, has sensorimotor demyelinating polyneuropathy. PATIENT CONCERNS: The patient presented with a 1-month history of progressive numbness at the distal extremities and motor weakness of the lower limbs. Meanwhile, patient also endorsed a painful lump on her right cheek. And then the enlarged cervical and supra clavicular lymph nodes were observed on admission. Biopsy of the lymph nodes showed NHL. Serum IgM antibodies against GM1 and GD1b were also positive. DIAGNOSIS: Biopsy of the lymph nodes showed NHL. Serum IgM antibodies against GM1 and GD1b were also positive. Thus, the patience was diagnosed with lymphoma and sensorimotor polyneuropathy. INTERVENTIONS: Patient refused the further treatment. OUTCOMES: After 11-month follow-up, the weakness of bilateral lower limbs worsens. LESSONS: We have presented a case of NHL involving peripheral polyneuropathy with IgM antibodies against GM1 and GD1b. Patients may initially present with peripheral nerve complications or develop them during the course of lymphoma, even when in remission. This could complicate the diagnosis of peripheral polyneuropathy secondary to NHL.

The term "floating" used in traumatic orthopedics.

BACKGROUND: The term "floating" is used in orthopedic literature to describe certain patterns of skeletal injuries that share one common character which is disruption and discontinuity of bones above and below a joint. The first time used in orthopedic literature being in late 1970 to describe a type of elbow injury. Later the word was used increasingly and applied to a variety of injuries affecting the knee, shoulder, hip, forearm, hand, and ankle. Currently, there are about 12 different skeletal injuries described as floating. OBJECTIVES: The aim of this article was to define the term "floating" used in traumatic orthopedics and to discuss its history, mechanism of injury in each region, treatment and outcomes based on the currently available literature. As there were many separate articles describing different sites of floating injuries, this review aimed to summarize all floating injuries into 1 article.

Effect of Ketamine on LTP and NMDAR EPSC in Hippocampus of the Chronic Social Defeat Stress Mice Model of Depression.

Depression is a common mental disorder that is associated with memory dysfunction. Ketamine has recently been demonstrated to be a rapid antidepressant. The mechanisms underlying how depression induces memory dysfunction and how ketamine relieves depressive symptoms remain poorly understood. This work compared three groups of male C57BL/6J mice: mice exposed to chronic social defeat stress (CSDS) to induce a depression-like phenotype, depression-like mice treated with ketamine, and control mice that were not exposed to CSDS or treated with ketamine. Spatial working memory and long term memory were assessed by spontaneous alternation Y-maze and fear conditioning tests, respectively. We used western blot to analyze the density of N-methyl-D-aspartate receptor (NMDAR) subunits in the hippocampus. We recorded long term potentiation (LTP) and NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) in hippocampal slices. We observed that compared with control mice, depression-like mice had significant reductions in spatial working memory and contextual fear memory. The level of NR2B, LTP and NMDA receptor-mediated EPSCs of depression-like mice were decreased. Ketamine treatment attenuated the memory impairment, and increased the density of NR2B and the amplitude of LTP and NMDA receptor-mediated EPSCs in the hippocampus of depression-like mice. In conclusion, depression-like mice have deficits in working memory and contextual fear memory. The decrease of NR2B, LTP induction and NMDA receptor-mediated EPSCs in the hippocampus may be involved in this process. Ketamine can improve expression of NR2B, LTP induction and NMDA receptor-mediated EPSCs in the hippocampus of depression-like mice, which might be part of the reason why ketamine can alleviate the memory dysfunction induced by depression.

Emerging Roles of Astrocytes in Neuro-Vascular Unit and the Tripartite Synapse With Emphasis on Reactive Gliosis in the Context of Alzheimer's Disease.

Astrocytes, which are five-fold more numerous than neurons in the central nervous system (CNS), are traditionally viewed to provide simple structural and nutritional supports for neurons and to participate in the composition of the blood brain barrier (BBB). In recent years, the active roles of astrocytes in regulating cerebral blood flow (CBF) and in maintaining the homeostasis of the tripartite synapse have attracted increasing attention. More importantly, astrocytes have been associated with the pathogenesis of Alzheimer's disease (AD), a major cause of dementia in the elderly. Although microglia-induced inflammation is considered important in the development and progression of AD, inflammation attributable to astrogliosis may also play crucial roles. A1 reactive astrocytes induced by inflammatory stimuli might be harmful by up-regulating several classical complement cascade genes thereby leading to chronic inflammation, while A2 induced by ischemia might be protective by up-regulating several neurotrophic factors. Here we provide a concise review of the emerging roles of astrocytes in the homeostasis maintenance of the neuro-vascular unit (NVU) and the tripartite synapse with emphasis on reactive astrogliosis in the context of AD, so as to pave the way for further research in this area, and to search for potential therapeutic targets of AD.

Inhibition of the Ubc9 E2 SUMO-conjugating enzyme-CRMP2 interaction decreases NaV1.7 currents and reverses experimental neuropathic pain.

We previously reported that destruction of the small ubiquitin-like modifier (SUMO) modification site in the axonal collapsin response mediator protein 2 (CRMP2) was sufficient to selectively decrease trafficking of the voltage-gated sodium channel NaV1.7 and reverse neuropathic pain. Here, we further interrogate the biophysical nature of the interaction between CRMP2 and the SUMOylation machinery, and test the hypothesis that a rationally designed CRMP2 SUMOylation motif (CSM) peptide can interrupt E2 SUMO-conjugating enzyme Ubc9-dependent modification of CRMP2 leading to a similar suppression of NaV1.7 currents. Microscale thermophoresis and amplified luminescent proximity homogeneous alpha assay revealed a low micromolar binding affinity between CRMP2 and Ubc9. A heptamer peptide harboring CRMP2's SUMO motif, also bound with similar affinity to Ubc9, disrupted the CRMP2-Ubc9 interaction in a concentration-dependent manner. Importantly, incubation of a tat-conjugated cell-penetrating peptide (t-CSM) decreased sodium currents, predominantly NaV1.7, in a model neuronal cell line. Dialysis of t-CSM peptide reduced CRMP2 SUMOylation and blocked surface trafficking of NaV1.7 in rat sensory neurons. Fluorescence dye-based imaging in rat sensory neurons demonstrated inhibition of sodium influx in the presence of t-CSM peptide; by contrast, calcium influx was unaffected. Finally, t-CSM effectively reversed persistent mechanical and thermal hypersensitivity induced by a spinal nerve injury, a model of neuropathic pain. Structural modeling has now identified a pocket-harboring CRMP2's SUMOylation motif that, when targeted through computational screening of ligands/molecules, is expected to identify small molecules that will biochemically and functionally target CRMP2's SUMOylation to reduce NaV1.7 currents and reverse neuropathic pain.

Homology-guided mutational analysis reveals the functional requirements for antinociceptive specificity of collapsin response mediator protein 2-derived peptides.

BACKGROUND AND PURPOSE: N-type voltage-gated calcium (Cav 2.2) channels are critical determinants of increased neuronal excitability and neurotransmission accompanying persistent neuropathic pain. Although Cav 2.2 channel antagonists are recommended as first-line treatment for neuropathic pain, calcium-current blocking gabapentinoids inadequately alleviate chronic pain symptoms and often exhibit numerous side effects. Collapsin response mediator protein 2 (CRMP2) targets Cav 2.2 channels to the sensory neuron membrane and allosterically modulates their function. A 15-amino-acid peptide (CBD3), derived from CRMP2, disrupts the functional protein-protein interaction between CRMP2 and Cav 2.2 channels to inhibit calcium influx, transmitter release and acute, inflammatory and neuropathic pain. Here, we have mapped the minimal domain of CBD3 necessary for its antinociceptive potential. EXPERIMENTAL APPROACH: Truncated as well as homology-guided mutant versions of CBD3 were generated and assessed using depolarization-evoked calcium influx in rat dorsal root ganglion neurons, binding between CRMP2 and Cav 2.2 channels, whole-cell voltage clamp electrophysiology and behavioural effects in two models of experimental pain: post-surgical pain and HIV-induced sensory neuropathy induced by the viral glycoprotein 120. KEY RESULTS: The first six amino acids within CBD3 accounted for all in vitro activity and antinociception. Spinal administration of a prototypical peptide (TAT-CBD3-L5M) reversed pain behaviours. Homology-guided mutational analyses of these six amino acids identified at least two residues, Ala1 and Arg4, as being critical for antinociception in two pain models. CONCLUSIONS AND IMPLICATIONS: These results identify an antinociceptive scaffold core in CBD3 that can be used for development of low MW mimetics of CBD3. LINKED ARTICLES: This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.