Enhancing m^(6)A modification in the motor cortex facilitates corticospinal tract remodeling after spinal cord injury

Spinal cord injury typically causes corticospinal tract disruption. Although the disrupted corticospinal tract can self-regenerate to a certain degree, the underlying mechanism of this process is still unclear. N6-methyladenosine(m^(6)A) modifications are the most common form of epigenetic regulation at the RNA level and play an essential role in biological processes. However, whether m^(6)A modifications participate in corticospinal tract regeneration after spinal cord injury remains unknown. We found that expression of methyltransferase 14 protein(METTL14) in the locomotor cortex was high after spinal cord injury and accompanied by elevated m^(6)A levels. Knockdown of Mettl14 in the locomotor cortex was not favorable for corticospinal tract regeneration and neurological recovery after spinal cord injury. Through bioinformatics analysis and methylated RNA immunoprecipitation-quantitative polymerase chain reaction, we found that METTL14 regulated Trib2 expression in an m^(6)A-regulated manner, thereby activating the mitogen-activated protein kinase pathway and promoting corticospinal tract regeneration. Finally, we administered syringin, a stabilizer of METTL14, using molecular docking. Results confirmed that syringin can promote corticospinal tract regeneration and facilitate neurological recovery by stabilizing METTL14. Findings from this study reveal that m^(6)A modification is involved in the regulation of corticospinal tract regeneration after spinal cord injury.

Kdm6a-CNN1 axis orchestrates epigenetic control of traumainduced spinal cord microvascular endothelial cell senescence to balance neuroinflammation for improved neurological repair

Cellular senescence assumes pivotal roles in various diseases through the secretion of proinflammatory factors.Despite extensive investigations into vascular senescence associated with aging and degenerative diseases,the molecular mechanisms governing microvascular endothelial cell senescence induced by traumatic stress,particularly its involvement in senescence-induced inflammation,remain insufficiently elucidated.In this study,we present a comprehensive demonstration and characterization of microvascular endothelial cell senescence induced by spinal cord injury(SCI).Lysine demethylase 6A(Kdm6a),commonly known as UTX,emerges as a crucial regulator of cell senescence in injured spinal cord microvascular endothelial cells(SCMECs).Upregulation of UTX induces senescence in SCMECs,leading to an amplified release of proinflammatory factors,specifically the senescenceassociated secretory phenotype(SASP)components,thereby modulating the inflammatory microenvironment.Conversely,the deletion of UTX in endothelial cells shields SCMECs against senescence,mitigates the release of proinflammatory SASP factors,and promotes neurological functional recovery after SCI.UTX forms an epigenetic regulatory axis by binding to calponin 1(CNN1),orchestrating trauma-induced SCMECs senescence and SASP secretion,thereby influencing neuroinflammation and neurological functional repair.Furthermore,local delivery of a senolytic drug reduces senescent SCMECs and suppresses proinflammatory SASP secretion,reinstating a local regenerative microenvironment and enhancing functional repair after SCI.In conclusion,targeting the UTX-CNN1 epigenetic axis to prevent trauma-induced SCMECs senescence holds the potential to inhibit SASP secretion,alleviate neuroinflammation,and provide a novel treatment strategy for SCI repair.

Ciliary parathyroid hormone signaling activates transforming growth factor-βto maintain intervertebral disc homeostasis during aging

Degenerative disc disease(DDD) is associated with intervertebral disc degeneration of spinal instability. Here, we report that the cilia of nucleus pulposus(NP) cells mediate mechanotransduction to maintain anabolic activity in the discs. We found that mechanical stress promotes transport of parathyroid hormone 1 receptor(PTH1 R) to the cilia and enhances parathyroid hormone(PTH) signaling in NP cells. PTH induces transcription of integrin α_vβ_6 to activate the transforming growth factor(TGF)-β-connective tissue growth factor(CCN2)-matrix proteins signaling cascade. Intermittent injection of PTH(iPTH) effectively attenuates disc degeneration of aged mice by direct signaling through NP cells, specifically improving intervertebral disc height and volume by increasing levels of TGF-β activity, CCN2, and aggrecan. PTH1 R is expressed in both mouse and human NP cells. Importantly,knockout PTH1 R or cilia in the NP cells results in significant disc degeneration and blunts the effect of PTH on attenuation of aged discs. Thus, mechanical stress-induced transport of PTH1 R to the cilia enhances PTH signaling, which helps maintain intervertebral disc homeostasis, particularly during aging, indicating therapeutic potential of iPTH for DDD.

Prediction of Landscape Pattern of Soft Sandstone Area (SSA) after Seabuckthorn Planting

As a pioneer plant in the gully slopes in the Soft Sandstone Area (SSA) for eco-economical consideration, ten years (1999-2008) planting of seabuckthorn has made 1642.83 km2, or 9.84%, of the total area of SSA change into seabuckthorn coverage. In SSA the landscape has been divided into 9 types, such as seabuckthorn, sand, water, settlement, bush, open vegetation, forest, grassland and unused land. Seabuckthorn type is separated from the bush type for estimating the role of seabuckthron planting. By means of the Markov model, the developing trends of every landscape types can be determined to support the seabuckthorn project which influences the landscape pattern deeply in SSA. The prediction shows that the optimism ratio of seabuckthorn in the future should be 10.21%, the open vegetation 32.25%, and the forest percentage under 10%, which is a very wise tactics to avoid the serious death of various vegetations in SSA to match the local arid eco-environment.

猪繁殖与呼吸综合征植物亚单位疫苗的免疫学研究

目前,防控猪繁殖与呼吸综合征(PRRS)主要采用灭活疫苗和弱毒活疫苗。然而,灭活疫苗的效率十分有限,弱毒活疫苗的安全问题又令人担忧,所以研制新型疫苗非常必要。本试验尝试使用转基因植物这种经济有效且有可扩展性的体系表达和传递病毒蛋白,并制成PRRS口服亚单位疫苗。通过转基因技术利用玉米愈伤组织表达PRRSV的病毒膜蛋白M蛋白。小鼠口服转基因植物组织可诱导体内产生血清抗体和肠系膜抗原特异性抗体,且血清抗体和黏膜抗体表现出病毒中和活性。终免后血清和粪便中的中和抗体滴度可分别达到6.7和3.7。接种动物脾细胞内也可检测到PRRSV特异性IFN-γ反应。结果表明,转基因玉米是一种有效的PRRS亚单位疫苗产品,口服后可激发机体产生抗PRRS的系统免疫应答和黏膜免疫应答。

Evaluation on Environmental Resource Value of Artificial Seabuckthorn Forest in Sandstone Area during 1999-2008

China Seabuckthorn Ecological Project has been implemented for a decade (from 1999 to 2008) with an increasing seabuckthorn area of 1642.83 km2 in?the Sandstone Areas of Shanxi, Shaanxi and Inner Mongolia—the most serious soil erosion area in China. The vast artificial seabuckthorn forest’s value in environmental resource is assessed via 7 indicators on first-level, 15 indicators on secondary level and 35 indicators on third level in this research. As of 2008, the seabuckthorn environmental resource value is 10.017 billion RMB Yuan, which equals to 37.1 times of the project’s total investment of 0.27 billion RMB Yuan. It is proposed in this research that the external economical values such as soil and water conservation, windbreak and sand-fixation can be realized through relative national policies and taxes. Carbon-fixation and oxygen-producing value can be achieved through the international carbon trade.

Targeted transplantation of engineered mitochondrial compound promotes functional recovery after spinal cord injury by enhancing macrophage phagocytosis

Mitochondria are crucial in sustaining and orchestrating cellular functions.Capitalizing on this,we explored mitochondrial transplantation as an innovative therapeutic strategy for acute spinal cord injury(SCI).In our study,we developed an engineered mitochondrial compound tailored to target macrophages within the SCI region.Sourced from IL-10-induced Mertkhi bone marrow-derived macrophages,we conjugated a peptide sequence,cations-cysteine-alanine-glutamine-lysine(CAQK),with the mitochondria,optimizing its targeting affinity for the injury site.Our data demonstrated that these compounds significantly enhanced macrophage phagocytosis of myelin debris,curtailed lipid buildup,ameliorated mitochondrial dysfunction,and attenuated pro-inflammatory profiles in macrophages,both in vitro and in vivo.The intravenously delivered mitochondrial compounds targeted the SCI epicenter,with macrophages being the primary recipients.Critically,they promoted tissue regeneration and bolstered functional recovery in SCI mice.This study heralds a transformative approach to mitochondrial transplantation in SCI,spotlighting the modulation of macrophage activity,phagocytosis,and phenotype.

Local delivery of EGFR+NSCs-derived exosomes promotes neural regeneration post spinal cord injury via miR-34a-5p/HDAC6 pathway

Spinal cord injury(SCI)causes severe axon damage,usually leading to permanent paraparesis,which still lacks effective regenerative therapy.Recent studies have suggested that exosomes derived from neural stem cells(NSCs)may hold promise as attractive candidates for SCI treatment.Epidermal Growth Factor Receptor positive NSC(EGFR+NSC)is a subpopulation of endogenous NSCs,showing strong regenerative capability in central nervous system disease.In the current study,we isolated exosomes from the EGFR+NSCs(EGFR+NSCs-Exos)and discovered that local delivery of EGFR+NSCs-Exos can effectively promote neurite regrowth in the injury site of spinal cord-injured mice and improve their neurological function recovery.Using the miRNA-seq,we firstly characterized the microRNAs(miRNAs)cargo of EGFR+NSCs-Exos and identified miR-34a-5p which was highly enriched in EGFR+NSCs derived exosomes.We further interpreted that exosomal miR-34a-5p could be transferred to neurons and inhibit the HDAC6 expression by directly binding to its mRNA,contributing to microtubule stabilization and autophagy induction for aiding SCI repair.Overall,our research demonstrated a novel therapeutic approach to improving neurological functional recovery by using exosomes secreted from a subpopulation of endogenous NSCs and providing a precise cell-free treatment strategy for SCI repair.

Crosstalk between RNA m^(6)A modification and epigenetic factors in plant gene regulation

N^(6)-methyladenosine(m^(6)A)is the most abundant modification observed in eukaryotic mRNAs.Advances in transcriptome-wide m^(6)A mapping and sequencing technologies have enabled the identification of several conserved motifs in plants,including the RRACH(R=A/G and H=A/C/U)and UGUAW(W=U or A)motifs.However,the mechanisms underlying deposition of m^(6)A marks at specific positions in the conserved motifs of individual transcripts remain to be clarified.Evidence from plant and animal studies suggests that m^(6)A writer or eraser components are recruited to specific genomic loci through interactions with particular transcription factors,5-methylcytosine DNA methylation marks,and histone marks.In addition,recent studies in animal cells have shown that microRNAs play a role in depositing m^(6)A marks at specific sites in transcripts through a base-pairing mechanism.m^(6)A also affects the biogenesis and function of chromatin-associated regulatory RNAs and long noncoding RNAs.Although we have less of an understanding of the link between m^(6)A modification and epigenetic factors in plants than in animals,recent progress in identifying the proteins that interact with m^(6)A writer or eraser components has provided insights into the crosstalk between m^(6)A modification and epigenetic factors,which plays a crucial role in transcript-specific methylation and regulation of m^(6)A in plants.

FLK is an mRNA m^(6)A reader that regulates floral transition by modulating the stability and splicing of FLC in Arabidopsis

N^(6)-methyladenosine(m^(6)A),which is added,removed,and interpreted by m^(6)A writers,erasers,and readers,respectively,is the most abundant modification in eukaryotic mRNAs.The m^(6)A marks play a pivotal role in the regulation of floral transition in plants.FLOWERING LOCUS K(FLK),an RNA-binding protein harboring K-homology(KH)motifs,is known to regulate floral transition by repressing the levels of a key floral repressor FLOWERING LOCUS C(FLC)in Arabidopsis.However,the molecular mechanism underlying FLK-mediated FLC regulation remains unclear.In this study,we identified FLK as a novel mRNA m^(6)A reader protein that directly binds the m^(6)A site in the 3ʹ-untranslated region of FLC transcripts to repressing FLC levels by reducing its stability and splicing.Importantly,FLK binding of FLC transcripts was abolished in vir-1,an m^(6)A writer mutant,and the late-flowering phenotype of the flk mutant could not be rescued by genetic complementation using the mutant FLKm gene,in which the m^(6)A reader encoding function was eliminated,indicating that FLK binds and regulates FLC expression in an m^(6)A-dependent manner.Collectively,our study has addressed a long-standing question of how FLK regulates FLC transcript levels and established a molecular link between the FLK-mediated recognition of m^(6)A modifications on FLC transcripts and floral transition in Arabidopsis.

Engineering an enthesis-like graft for rotator cuff repair:An approach to fabricate highly biomimetic scaffold capable of zone-specifically releasing stem cell differentiation inducers

Rotator cuff(RC)attaches to humerus across a triphasic yet continuous tissue zones(bone-fibrocartilage-tendon),termed“enthesis”.Regrettably,rapid and functional enthesis regeneration is challenging after RC tear.The existing grafts bioengineered for RC repair are insufficient,as they were engineered by a scaffold that did not mimic normal enthesis in morphology,composition,and tensile property,meanwhile cannot simultaneously stimulate the formation of bone-fibrocartilage-tendon tissues.Herein,an optimized decellularization approach based on a vacuum aspiration device(VAD)was developed to fabricate a book-shaped decellularized enthesis matrix(O-BDEM).Then,three recombinant growth factors(CBP-GFs)capable of binding collagen were synthesized by fusing a collagen-binding peptide(CBP)into the N-terminal of BMP-2,TGF-β3,or GDF-7,and zone-specifically tethered to the collagen of O-BDEM to fabricate a novel scaffold(CBP-GFs/O-BDEM)satisfying the above-mentioned requirements.After ensuring the low immunogenicity of CBP-GFs/O-BDEM by a novel single-cell mass cytometry in a mouse model,we interleaved urine-derived stem cell-sheets into this CBP-GFs/O-BDEM to bioengineer an enthesis-like graft.Its high-performance on regenerating enthesis was determined in a canine model.These findings indicate this CBP-GFs/O-BDEM may be an excellent scaffold for constructing enthesis-like graft to patch large/massive RC tears,and provide breakthroughs in fabricating graded interfacial tissue.

Simultaneous 3D Visualization of the Microvascular and Neural Network in Mouse Spinal Cord Using Synchrotron Radiation Micro-Computed Tomography

Effective methods for visualizing neurovascular morphology are essential for understanding the normal spinal cord and the morphological alterations associated with diseases.However,ideal techniques for simultaneously imaging neurovascular structure in a broad region of a specimen are still lacking.In this study,we combined Golgi staining with angiography and synchrotron radiation micro-computed tomography(SRμCT)to visualize the 3D neurovascular network in the mouse spinal cord.Using our method,the 3D neurons,nerve fibers,and vasculature in a broad region could be visualized in the same image at cellular resolution without destructive sectioning.Besides,we found that the 3D morphology of neurons,nerve fiber tracts,and vasculature visualized by SRjiCT were highly consistent with that visualized using the histological method.Moreover,the 3D neurovascular structure could be quantitatively evaluated by the combined methodology.The method shown here will be useful in fundamental neuroscience studies.

The trivalent cerium-induced cell death and alteration of ion flux in sweetpotato [Ipomoea batatas(L.) Lam]

The rare earth element cerium（Ce） in its several forms is extensively utilized in various fields, including nano-technology, agriculture, and the food industry. Due to its increasing unregulated usage, Ce is now a potential source of pollution and toxicity due to its excessive environmental accumulation. Unfortunately, analysis of the toxic effects of Ce in plants is still in its early stages. Herein, we investigated the effects of Ce3＋ treatment on development-related indicators in sweetpotato. We found that a low concentration（10 mg/L） slightly improved oxidation resistance, while a high concentration（20-80 mg/L）negatively affected development and photosynthesis and triggered increases in reactive oxygen species（ROS） production, antioxidant enzyme activities, and malondialdehyde（MDA） content. Moreover,elevation and efflux of cytosolic Ca^（2＋） and caspase-l-like activity were induced by high-concentration Ce^（3＋） treatment. Finally, cell viability decreased as Ce3＋ concentration increased. These results suggest that（1） a high Ce3＋ concentration（20-80 mg/L） inhibits development and photosynthesis of sweetpotato and induces oxidative damage followed by lipid peroxidation in the root,（2） a caspase-l-like protease is induced by cytosolic Ca^（2＋） and ROS overproduction to cause programmed cell death in the root, and（3） a high concentration of Ce3＋ could trigger a hypothetical cell death pathway, wherein Ce3＋induces ROS production followed by cytosolic Ca^（2＋） elevation, which activates caspase-l-like activity,which in turn leads to programmed cell death in the root of sweetpotato.