RNA sequencing of exosomes secreted by fibroblast and Schwann cells elucidates mechanisms underlying peripheral nerve regeneration

Exosomes exhibit complex biological functions and mediate a variety of biological processes,such as promoting axonal regeneration and functional recove ry after injury.Long non-coding RNAs(IncRNAs)have been reported to play a crucial role in axonal regeneration.Howeve r,the role of the IncRNA-microRNAmessenger RNA(mRNA)-competitive endogenous RNA(ceRNA)network in exosome-mediated axonal regeneration remains unclear.In this study,we performed RNA transcriptome sequencing analysis to assess mRNA expression patterns in exosomes produced by cultured fibroblasts(FC-EXOs)and Schwann cells(SCEXOs).Diffe rential gene expression analysis,Gene Ontology analysis,Kyoto Encyclopedia of Genes and Genomes analysis,and protein-protein intera ction network analysis were used to explo re the functions and related pathways of RNAs isolated from FC-EXOs and SC-EXOs.We found that the ribosome-related central gene Rps5 was enriched in FC-EXOs and SC-EXOs,which suggests that it may promote axonal regeneration.In addition,using the miRWalk and Starbase prediction databases,we constructed a regulatory network of ceRNAs targeting Rps5,including 27 microRNAs and five IncRNAs.The ceRNA regulatory network,which included Ftx and Miat,revealed that exsosome-derived Rps5 inhibits scar formation and promotes axonal regeneration and functional recovery after nerve injury.Our findings suggest that exosomes derived from fibro blast and Schwann cells could be used to treat injuries of peripheral nervous system.

Ploidy and fruit trait variation in oil-tea Camellia:Implications for ploidy breeding

Plant polyploidy often occurs in conjunction with higher yield and superior quality.Therefore,obtaining polyploid germplasms is a significant part of breeding.The oil-tea Camellia tree is an important native woody plant that produces high-quality edible oil and includes many species of Camellia with different ploidies.However,whether higher ploidy levels in oil-tea Camellia trees are related to better traits remains unclear.In this study,the ploidy levels of 30 different oil-tea Camellia strains in three different species in the Sect.Paracamellia were determined by flow cytometry and chromosome preparation,and the phenotypic characteristics and fatty acid compositions of the fruits were examined by field observations and laboratory analyses.The correlations between the ploidy level of oil-tea Camellia and the main traits of the fruit were investigated.Our results showed that 10 Camellia lanceoleosa strains were diploid,10 Camellia meiocarpa strains were tetraploid and 10 Camellia oleifera strains were hexaploid.Hexaploid C.oleifera had larger fruit size and weight,more seeds per fruit,greater seed weight per fruit,higher oil content and greater yield per crown width than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their fruit peel thickness and fresh seed rate were significantly lower,and these traits were significantly correlated with ploidy level.In addition,in terms of fatty acid composition,hexaploid C.oleifera had a higher oleic acid content than tetraploid C.meiocarpa and diploid C.lanceoleosa,but their linoleic acid,linolenic acid and arachidonic acid contents were lower.The contents of palmitic acid,stearic acid and total unsaturated fatty acids were not significantly correlated with ploidy level.In conclusion,certain correlations exist between the main characteristics of oil-tea Camellia fruit and the ploidy level,and increasing the ploidy level led to an increase in fruit yield with no effect on oil composition.The discovery of variations in the main characteristics of oil-tea Camellia fruit with different ploidies will facilitate germplasm innovation and lay a foundation for ploidy breeding and mechanistic research on fruit traits.

Dual-Branch-UNet: A Dual-Branch Convolutional Neural Network for Medical Image Segmentation

In intelligent perception and diagnosis of medical equipment,the visual and morphological changes in retinal vessels are closely related to the severity of cardiovascular diseases(e.g.,diabetes and hypertension).Intelligent auxiliary diagnosis of these diseases depends on the accuracy of the retinal vascular segmentation results.To address this challenge,we design a Dual-Branch-UNet framework,which comprises a Dual-Branch encoder structure for feature extraction based on the traditional U-Net model for medical image segmentation.To be more explicit,we utilize a novel parallel encoder made up of various convolutional modules to enhance the encoder portion of the original U-Net.Then,image features are combined at each layer to produce richer semantic data and the model’s capacity is adjusted to various input images.Meanwhile,in the lower sampling section,we give up pooling and conduct the lower sampling by convolution operation to control step size for information fusion.We also employ an attentionmodule in the decoder stage to filter the image noises so as to lessen the response of irrelevant features.Experiments are verified and compared on the DRIVE and ARIA datasets for retinal vessels segmentation.The proposed Dual-Branch-UNet has proved to be superior to other five typical state-of-the-art methods.

Fidgetin interacting with microtubule end binding protein EB3 affects axonal regrowth in spinal cord injury

Fidgetin,a microtubule-severing enzyme,regulates neurite outgrowth,axonal regeneration,and cell migration by trimming off the labile domain of microtubule polymers.Because maintenance of the microtubule labile domain is essential for axon initiation,elongation,and navigation,it is of interest to determine whether augmenting the microtubule labile domain via depletion of fidgetin serves as a therapeutic approach to promote axonal regrowth in spinal cord injury.In this study,we constructed rat models of spinal cord injury and sciatic nerve injury.Compared with spinal cord injury,we found that expression level of tyrosinated microtubules in the labile portion of microtubules continuously increased,whereas fidgetin decreased after peripheral nerve injury.Depletion of fidgetin enhanced axon regeneration after spinal cord injury,whereas expression level of end binding protein 3(EB3)markedly increased.Next,we performed RNA interference to knockdown EB3 or fidgetin.We found that deletion of EB3 did not change fidgetin expression.Conversely,deletion of fidgetin markedly increased expression of tyrosinated microtubules and EB3.Deletion of fidgetin increased the amount of EB3 at the end of neurites and thereby increased the level of tyrosinated microtubules.Finally,we deleted EB3 and overexpressed fidgetin.We found that fidgetin trimmed tyrosinated tubulins by interacting with EB3.When fidgetin was deleted,the labile portion of microtubules was elongated,and as a result the length of axons and number of axon branches were increased.These findings suggest that fidgetin can be used as a novel therapeutic target to promote axonal regeneration after spinal cord injury.Furthermore,they reveal an innovative mechanism by which fidgetin preferentially severs labile microtubules.

Co-culture of Schwann cells and endothelial cells for synergistically regulating dorsal root ganglion behavior on chitosan-based anisotropic topology for peripheral nerve regeneration

Background:Anisotropic topologies are known to regulate cell-oriented growth and induce cell differentiation,which is conducive to accelerating nerve regeneration,while co-culture of endothelial cells(ECs)and Schwann cells(SCs)can significantly promote the axon growth of dorsal root ganglion(DRG).However,the synergistic regulation of EC and SC co-culture of DRG behavior on anisotropic topologies is still rarely reported.The study aims to investigate the effect of anisotropic topology co-cultured with Schwann cells and endothelial cells on dorsal root ganglion behavior for promoting peripheral nerve regeneration.Methods:Chitosan/artemisia sphaerocephala(CS/AS)scaffolds with anisotropic topology were first prepared using micro-molding technology,and then the surface was modified with dopamine to facilitate cell adhesion and growth.The physical and chemical properties of the scaffolds were characterized through morphology,wettability,surface roughness and component variation.SCs and ECs were co-cultured with DRG cells on anisotropic topology scaffolds to evaluate the axon growth behavior.Results:Dopamine-modified topological CS/AS scaffolds had good hydrophilicity and provided an appropriate environment for cell growth.Cellular immunofluorescence showed that in contrast to DRG growth alone,co-culture of SCs and ECs could not only promote the growth of DRG axons,but also offered a stronger guidance for orientation growth of neurons,which could effectively prevent axons from tangling and knotting,and thus may significantly inhibit neurofibroma formation.Moreover,the co-culture of SCs and ECs could promote the release of nerve growth factor and vascular endothelial growth factor,and up-regulate genes relevant to cell proliferation,myelination and skeletal development via the PI3K-Akt,MAPK and cytokine and receptor chemokine pathways.Conclusions:The co-culture of SCs and ECs significantly improved the growth behavior of DRG on anisotropic topological scaffolds,which may provide an important basis for the development of nerve grafts in peripheral nerve regeneration.

A NOVEL DRIVING STRATEGY FOR DYNAMIC SIMULATION OF HOISTING ROPE WITH TIME-VARYING LENGTH

A simulation method for investigating the vibration behavior of hoisting rope with time-varying length is improved.By previously creating markers in the MSC.ADAMS software package,the parametric model of the rope wound along helix is established based on the concentrated-mass theory with multi-degree of freedom(multi-DOF).A novel driving strategy,cooperating fixed joints with angle sensors under the control of driving script,is proposed to substitute conventional contact force.Researching on the hoisting rope in the sinking winch mechanism,an equivalent discretization model is obtained with complicated boundary conditions considered.The differential equations of motion of the hoisting system are formulated employing Lagrange’s equation and numerically solved using Runge–Kutta method.The simulation indicates that the horizontal swing is decreased in principle and the simulation with 800 discrete ropes is not performed more than 61 min.Therefore,this feasible strategy could not only guarantee the accuracy but also promote simulation efficiency and stability.The motion curves exported from ADAMS simulation coincide with one in numerical simulation,which validates both the numerical model and the driving strategy.

Radiometric Cross-Calibration for Multiple Sensors with the Moon as an Intermediate Reference

The instrument cross-calibration is an effective way to assess the quality of satellite data. In this study, a new method is proposed to cross-calibrate the sensors among satellite instruments by using a RObotic Lunar Observatory(ROLO) model and Apollo sample reflectance in reflective solar bands(RSBs). The ROLO model acts as a transfer radiometer to bridge between the instruments. The reflective spectrum of the Apollo sample is used to compensate for the difference in the instrument's relative spectral responses(RSRs). In addition, the double ratio between the observed lunar irradiance and the simulated lunar irradiance is used to reduce the difference in instrument lunar viewing and illumining geometry. This approach is applied to the Moderate Resolution Imaging Spectroradiometer(MODIS), the Sea-Viewing Wide Field-of-View Sensor(Sea Wi FS), and the Advanced Land Imager(ALI) on board three satellites, respectively. The mean difference between MODIS and Sea Wi FS is less than 3.14%, and the difference between MODIS and ALI is less than 4.75%. These results indicate that the proposed cross-calibration method not only compensates for the RSR mismatches but also reduces the differences in lunar observation geometry. Thus,radiance calibration of any satellite instrument can be validated with a reference instrument bridged by the moon.

Long-Term Consistent Recalibration of VIRR Solar Reflectance Data Record for Fengyun Polar-Orbiting Satellites

The visible infrared radiometer(VIRR)is the first instrument with longest measurements equipped on the Fengyun(FY)polar-orbiting satellites.Through re-processing of the historic VIRR measurements,long-term(over 20 yr)global data can be integrated from multiple participating VIRRs on a consistent radiometric scale,which are valuable to climate and climate change studies.Due to lack of an onboard calibration system for VIRR,the reflective solar bands must be vicariously calibrated.This study applied the multi-site vicarious approach for consistent calibration of the VIRR visible(VIS)and near-infrared(NIR)data,and produced calibration coefficients for five VIRRs on FY-1 C/D and FY-3 A/B/C.The data quality was then evaluated with observations.The reflectance predicted by using the radiative transfer model over multiple invariant desert and ocean targets was used to derive the calibration slope via a weighted fitting scheme,in which the weights are the inverse of the variance from a radiative transfer simulation evaluated with reference to Aqua moderate resolution imaging spectroradiometer(MODIS).The sensor-specific calibration coefficients were derived on a daily basis by using piecewise polynomials.The calibration reference of the VIRR solar band record was further traced to the Aqua MODIS Collection 6.1 reference calibration with a systematic correction derived from the Libya4 desert.The VIRR record was compared with the Aqua MODIS C6.1 calibration over the polar region based on simultaneous nadir overpass observations.The lifetime relative difference for each sensor are within 3.3%and 4.5%for channels 1 and 2.Invariant deserts were also employed to evaluate the stability and consistency of the VIRR record.In general,the means of the directional and spectral corrected reflectance for each sensor are within 1%of the 20-yr average,implying that the VIRR reflectance of the invariant targets is consistent to within 1%among the sensors for channels 1 and 2.The VIRR data thus derived are reliable.