Subtype Identification in Acutely Dissociated Rat Nodose Ganglion Neurons Based on Morphologic Parameters

Nodose ganglia are composed of A-, Ah- and C-type neurons. Despite their important roles in regulating visceral afferent function, including cardiovascular, pulmonary, and gastrointestinal homeostasis, information about subtype-specific expression, molecular identity, and function of individual ion transporting proteins is scarce. Although experiments utilizing the sliced ganglion preparation have provided valuable insights into the electrophysiological properties of nodose ganglion neuron subtypes, detailed characterization of their electrical phenotypes will require measurements in isolated cells. One major unresolved problem, however, is the difficulty to unambiguously identify the subtype of isolated nodose ganglion neurons without current-clamp recording, because the magnitude of conduction velocity in the corresponding afferent fiber, a reliable marker to discriminate subtypes in situ, can no longer be determined. Here, we present data supporting the notion that application of an algorithm regarding to microscopic structural characteristics, such as neuron shape evaluated by the ratio between shortest and longest axis, neuron surface characteristics, like membrane roughness, and axon attachment, enables specific and sensitive subtype identification of acutely dissociated rat nodose ganglion neurons, by which the accuracy of identification is further validated by electrophysiological markers and overall positive predictive rates is 89.26% (90.04%, 76.47%, and 98.21% for A-, Ah, and C-type, respectively). This approach should aid in gaining insight into the molecular correlates underlying phenotypic heterogeneity of nodose ganglia. Additionally, several critical points that help for neuron identification and afferent conduction calibration are also discussed.     

Diabetes Inhibits Cerebral Ischemia-Induced Astrocyte Activation - an Observation in the Cingulate Cortex

The objective of this study was to study the effect of diabetic hyperglycemia on astrocytes after forebrain ischemia. Streptozotocin (STZ)-injected hyperglycemic and vehicle-injected normoglycemic rats were subjected to 15 minutes of forebrain ischemia. The brains were harvested in sham-operated controls and in animals with 1 and 6 h of recirculation following ischemia. Brain damage was accessed by haematoxylin and eosin (H&E) staining, cleaved caspase-3 immunohistochemistry and TdT-mediated-dUTP nick end labeling (TUNEL). Anti-GFAP antibody was employed to study astrocytes. The results showed that the 15-minute ischemia caused neuronal death after 1 and 6 h of reperfusion as revealed by increased numbers of karyopyknotic cells, edema, TUNEL-positive and active caspase-3-positive cells. Ischemia also activated astrocytes in the cingulated cortex as reflected by astrocyte stomata hypertrophy, elongated dendrites and increases in the number of dendrites, and immunoreactivity of GFAP. Diabetic hyperglycemia further enhanced neuronal death and suppressed ischemia-induced astrocyte activation. Further, diabetes-damaged astrocytes have increased withdrawal of the astrocyte end-foot from the cerebral blood vessel wall. It is concluded that diabetes-induced suppression and damages to astrocytes may contribute to its detrimental effects on recovery from cerebral ischemia.     

Ve1‐mediated resistance against Verticillium does not involve a hypersensitive response in Arabidopsis

The recognition of pathogen effectors by plant immune receptors leads to the activation of immune responses that often include a hypersensitive response (HR): rapid and localized host cell death surrounding the site of attempted pathogen ingress. We have demonstrated previously that the recognition of the Verticillium dahliae effector protein Ave1 by the tomato immune receptor Ve1 triggers an HR in tomato and tobacco. Furthermore, we have demonstrated that tomato Ve1 provides Verticillium resistance in Arabidopsis upon Ave1 recognition. In this study, we investigated whether the co‐expression of Ve1 and Ave1 in Arabidopsis results in an HR, which could facilitate a forward genetics screen. Surprisingly, we found that the co‐expression of Ve1 and Ave1 does not induce an HR in Arabidopsis. These results suggest that an HR may occur as a consequence of Ve1/Ave1‐induced immune signalling in tomato and tobacco, but is not absolutely required for Verticillium resistance.     

Inhibition of in vivo Slicer activity of Argonaute protein 1 by the viral 2b protein independent of its dsRNA‐binding function

The 2b protein of Cucumber mosaic virus (CMV) has several unique properties, such as targeting to the nucleolus and interaction with both Argonautes (AGOs) and short and long double‐stranded RNA (dsRNA). We have recently uncoupled the domain requirements for dsRNA binding and nucleolar targeting from the physical interactions with AGO proteins, and have found that the direct 2b–AGO interaction is sufficient to inhibit the in vitro AGO1 Slicer function independent of the other biochemical properties of 2b. Because the AGO binding activity of 2b is not required for its suppressor function in vivo, this raises the question of whether in vivo 2b–AGO interaction is possible to inhibit the in vivo AGO Slicer function. In this study, by taking advantage of a technology for the production of artificial trans‐acting small interfering RNA (tasiRNA), a process uniquely associated with AGO1‐mediated in vivo Slicer activity, we demonstrated that the expression of the 2b protein in planta interfered with the production of tasiRNA. Through further detailed analysis with deletion mutants of 2b proteins, we found that the inhibition of in vivo AGO1 Slicer function required the nucleolar localization signal (NoLS), in addition to the AGO‐binding domain, of the 2b protein. Our finding demonstrates that in vivo 2b–AGO1 interaction is sufficient to inhibit AGO1 Slicer function independent of the dsRNA‐binding activity of the 2b protein.     

Periodontal tissue regeneration by combined implantation of adipose tissue-derived stem cells and platelet-rich plasma in a canine model

Background aimsOne goal of periodontal therapy is to regenerate periodontal tissues. Stem cells, growth factors and scaffolds and biomaterials are vital for the restoration of the architecture and function of complex tissues. Adipose tissue-derived stem cells (ASCs) are an ideal population of stem cells for practical regenerative medicine. In addition, platelet-rich plasma (PRP) can be useful for its ability to stimulate tissue regeneration. PRP contains various growth factors and may be useful as a cell carrier in stem cell therapies. The purpose of this study was to determine whether a mixture of ASCs and PRP promoted periodontal tissue regeneration in a canine model.MethodsAutologous ASCs and PRP were implanted into areas with periodontal tissue defects. Periodontal tissue defects that received PRP alone or non-implantation were also examined. Histologic, immunohistologic and x-ray studies were performed 1 or 2 months after implantation. The amount of newly formed bone and the scale of newly formed cementum in the region of the periodontal tissue defect were analyzed on tissue sections.ResultsThe areas of newly formed bone and cementum were greater 2 months after implantation of ASCs and PRP than at 1 month after implantation, and the radiopacity in the region of the periodontal tissue defect increased markedly by 2 months after implantation. The ASCs and PRP group exhibited periodontal tissue with the correct architecture, including alveolar bone, cementum-like structures and periodontal ligament-like structures, by 2 months after implantation.ConclusionsThese findings suggest that a combination of autologous ASCs and PRP promotes periodontal tissue regeneration that develops the appropriate architecture for this complex tissue.     

Mesenchymal stem cell sheet transplantation combined with locally released simvastatin enhances bone formation in a rat tibia osteotomy model

Nonunion of fractured bones is a common clinical problem for orthopedic surgeons. This study aimed to investigate the effects of simvastatin locally applied from calcium sulfate (CS) combined with a mesenchymal stem cell (MSC) sheet on fracture healing. In vitro, the proliferation and differentiation of rat bone marrow–derived MSCs stimulated by simvastatin were investigated. In vivo, an osteotomy model was made in rat tibia, and fractured tibias were treated with CS, CS/simvastatin, CS/MSC sheet or simvastatin-loaded CS with MSC or untreated (control). Tibias were harvested at 2 or 8 weeks and underwent real-time quantitative polymerase chain reaction, x-ray, micro-CT and histological analysis. The expression levels of bone morphogenetic protein 2, alkaline phosphatase, osteocalcin, osteoprotegerin and vascular endothelial growth factor of simvastatin-induced MSCs increased with the concentrations of the simvastatin, significantly higher than those in the MSCs group. At 2 weeks, the CS/simvastatin/MSC sheet group showed significantly higher expressions of bone morphogenetic protein 2, alkaline phosphatase, osteocalcin, osteoprotegerin and vascular endothelial growth factor, with more callus formation around the fracture site compared with the other four groups. At 8 weeks, complete bone union was obtained in the CS/simvastatin/MSC sheet group. By contrast, newly regenerated bone tissue partially bridged the gap in the CS/simvastatin group and the CS/MSC sheet group; the control and CS group showed nonunion of the tibia. These results show that both simvastatin and the MSC sheet contributed to the formation of new bone and that the tibia fracture was completely healed by transplantation of the MSC sheet with locally applied simvastatin. Such MSC sheet with locally applied simvastatin might contribute to the treatment of fractures, bone delayed unions or nonunions in clinical practice.     

DDIG-in: discriminating between disease-associated and neutral non-frameshifting micro-indels

Micro-indels (insertions or deletions shorter than 21 bps) constitute the second most frequent class of human gene mutation after single nucleotide variants. Despite the relative abundance of non-frameshifting indels, their damaging effect on protein structure and function has gone largely unstudied. We have developed a support vector machine-based method named DDIG-in (Detecting disease-causing genetic variations due to indels) to prioritize non-frameshifting indels by comparing disease-associated mutations with putatively neutral mutations from the 1,000 Genomes Project. The final model gives good discrimination for indels and is robust against annotation errors. A webserver implementing DDIG-in is available at http://sparks-lab.org/ddig.