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.

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.

Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway

Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.

Novel ATL1 mutation in a Chinese family with hereditary spastic paraplegia: A case report and review of literature

BACKGROUND Hereditary spastic paraplegias (HSPs) refer to a group of heterogeneous neurodegenerative diseases characterized by lower limbs spasticity and weakness. So far, over 72 genes have been found to cause HSP (SPG1-SPG72). Among autosomal dominant HSP patients, spastic paraplegia 4 (SPG4/SPAST) gene is the most common pathogenic gene, and atlastin-1 (ATL1) is the second most common one. Here we reported a novel ATL1 mutation in a Chinese spastic paraplegia 3A (SPG3A) family, which expands the clinical and genetic spectrum of ATL1 mutations. CASE SUMMARY A 9-year-old boy with progressive spastic paraplegia accompanied by right hearing loss and mental retardation for five years was admitted to our hospital.Past history was unremarkable. The family history was positive, and his grandfather and mother had similar symptoms. Neurological examinations revealed hypermyotonia in his lower limbs, hyperreflexia in knee reflex, bilateral positive Babinski signs and scissors gait. The results of blood routine test, liver function test, blood glucose test, ceruloplasmin test and vitamin test were all normal. The serum lactic acid level was significantly increased. The testing for brainstem auditory evoked potential demonstrated that the right side hearing was impaired while the left was normal. Magnetic resonance imaging showed mild atrophy of the spinal cord. The gene panel test revealed that the proband carried an ATL1 c.752A>G p.Gln251Arg (p.Q251R) mutation, and Sanger sequencing confirmed the existence of family co-segregation. CONCLUSION We reported a novel ATL1 Q251R mutation and a novel clinical phenotype of hearing loss in a Chinese SPG3A family.

The lymphatic system:a therapeutic target for central nervous system disorders

The lymphatic vasculature forms an organized network that covers the whole body and is involved in fluid homeostasis,metabolite clearance,and immune surveillance.The recent identification of functional lymphatic vessels in the meninges of the brain and the spinal cord has provided novel insights into neurophysiology.They emerge as major pathways for fluid exchange.The abundance of immune cells in lymphatic vessels and meninges also suggests that lymphatic vessels are actively involved in neuroimmunity.The lymphatic system,through its role in the clearance of neurotoxic proteins,autoimmune cell infiltration,and the transmission of pro-inflammatory signals,participates in the pathogenesis of a variety of neurological disorders,including neurodegenerative and neuroinflammatory diseases and traumatic injury.Vascular endothelial growth factor C is the master regulator of lymphangiogenesis,a process that is critical for the maintenance of central nervous system homeostasis.In this review,we summarize current knowledge and recent advances relating to the anatomical features and immunological functions of the lymphatic system of the central nervous system and highlight its potential as a therapeutic target for neurological disorders and central nervous system repair.

Extracellular vesicles from human urine-derived stem cells prevent osteoporosis by transferring CTHRC1 and OPG

Osteoporosis is a debilitating bone disease affecting millions of people. Here, we used human urine-derived stem cells(USCs),which were noninvasively harvested from unlimited and easily available urine, as a "factory" to obtain extracellular vesicles(USCEVs) and demonstrated that the systemic injection of USC-EVs effectively alleviates bone loss and maintains bone strength in osteoporotic mice by enhancing osteoblastic bone formation and suppressing osteoclastic bone resorption. More importantly, the anti-osteoporotic properties of USC-EVs are not notably disrupted by the age, gender, or health condition(with or without osteoporosis) of the USC donor. Mechanistic studies determined that collagen triple-helix repeat containing 1(CTHRC1) and osteoprotegerin(OPG) proteins are enriched in USC-EVs and required for USC-EV-induced pro-osteogenic and anti-osteoclastic effects. Our results suggest that autologous USC-EVs represent a promising novel therapeutic agent for osteoporosis by promoting osteogenesis and inhibiting osteoclastogenesis by transferring CTHRC1 and OPG.

Omentin-1 prevents inflammation-induced osteoporosis by downregulating the pro-inflammatory cytokines

Osteoporosis is a frequent complication of chronic inflammatory diseases and increases in the pro-inflammatory cytokines make an important contribution to bone loss by promoting bone resorption and impairing bone formation. Omentin-1 is a newly identified adipocytokine that has anti-inflammatory effects, but little is known about the role of omentin-1 in inflammatory osteoporosis. Here we generated global omentin-1 knockout（omentin-1^-/-） mice and demonstrated that depletion of omentin-1 induces inflammatory bone loss-like phenotypes in mice, as defined by abnormally elevated pro-inflammatory cytokines, increased osteoclast formation and bone tissue destruction, as well as impaired osteogenic activities. Using an inflammatory cell model induced by tumor necrosis factor-α（TNF-α）, we determined that recombinant omentin-1 reduces the production of proinflammatory factors in the TNF-α-activated macrophages, and suppresses their anti-osteoblastic and pro-osteoclastic abilities. In the magnesium silicate-induced inflammatory osteoporosis mouse model, the systemic administration of adenoviral-delivered omentin-1 significantly protects from osteoporotic bone loss and inflammation. Our study suggests that omentin-1 can be used as a promising therapeutic agent for the prevention or treatment of inflammatory bone diseases by downregulating the proinflammatory cytokines.

Bone biomaterials and interactions with stem cells

Bone biomaterials play a vital role in bone repair by providing the necessary substrate for cell adhesion, proliferation, and differentiation and by modulating cell activity and function. In past decades, extensive efforts have been devoted to developing bone biomaterials with a focus on the following issues： （1） developing ideal biomaterials with a combination of suitable biological and mechanical properties; （2） constructing a cell microenvironment with pores ranging in size from nanoscale to submicro- and microscale; and （3） inducing the oriented differentiation of stem cells for artificial-to-biological transformation. Here we present a comprehensive review of the state of the art of bone biomaterials and their interactions with stem cells. Typical bone biomaterials that have been developed, including bioactive ceramics, biodegradable polymers, and biodegradable metals, are reviewed, with an emphasis on their characteristics and applications. The necessary porous structure of bone biomaterials for the cell microenvironment is discussed, along with the corresponding fabrication methods. Additionally, the promising seed stem cells for bone repair are summarized, and their interaction mechanisms with bone biomaterials are discussed in detail. Special attention has been paid to the signaling pathways involved in the focal adhesion and osteogenic differentiation of stem cells on bone biomaterials. Finally, achievements regarding bone biomaterials are summarized, and future research directions are proposed.

Mutations in GBA,SNCA,and VPS35 are not associated with Alzheimer's disease in a Chinese population:a case-control study

SNCA,GBA,and VPS35 are three common genes associated with Parkinson's disease.Previous studies have shown that these three genes may be associated with Alzheimer's disease(AD).However,it is unclear whether these genes increase the risk of AD in Chinese populations.In this study,we used a targeted gene sequencing panel to screen all the exon regions and the nearby sequences of GBA,SNCA,and VPS35 in a cohort including 721 AD patients and 365 healthy controls from China.The results revealed that neither common variants nor rare variants of these three genes were associated with AD in a Chinese population.These findings suggest that the mutations in GBA,SNCA,and VPS35 are not likely to play an important role in the genetic susceptibility to AD in Chinese populations.The study was approved by the Ethics Committee of Xiangya Hospital,Central South University,China on March 9,2016(approval No.201603198).

Microstructure, biodegradation, antibacterial and mechanical properties of ZK60-Cu alloys prepared by selective laser melting technique

Magnesium （Mg） alloys are receiving increasing attention for body implants owing to their good bio- compatibility and biodegradability. However, they often suffer from bacterial infections on account of their insufficient antibacterial ability. In this study, ZK60-xCu （x = O, 0.2, 0.4, 0.6 and 0.8 wt%） alloys were prepared by selective laser melting （SLM） with alloying copper （Cu） to enhance their antibacterial ability. Results showed that ZK60-Cu alloys exhibited strong antibacterial ability due to combination of release of Cu ions and alkaline environment which could kill bacteria by destroying cellular membrane structure, denaturing enzymes and inhibiting deoxyribonucleic acid （DNA） replication. In addition, their compres- sive strength increased due to grain refinement and uniformly dispersing of short-bar shaped MgZnCu phases. Moreover, ZK60-Cu alloys also exhibited good cytocompatibility. In summary, ZK60-Cu alloys with antibacterial ability may be Dromising implants for biomedical anDlications.

Transplantation of adult spinal cord grafts into spinal cord transected rats improves their locomotor function

Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor segments for allogeneic transplantation. Here, we utilized adult spinal cord tissue grafts(aSCGs) as donor constructs for repairing complete spinal cord injury(SCI). Moreover, to provide a favourable microenvironment for SCI treatment, a growth factor cocktail containing three growth factors(brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor), was applied to the aSCG transplants. We found that the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. Transplantation of aSCGs combined with these growth factors enhanced neuron and oligodendrocyte survival and functional restoration. These encouraging results indicate that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery, and therefore could be considered as a possible therapeutic strategy for SCI.

Single-cell RNA sequencing reveals Nestin+active neural stem cells outside the central canal after spinal cord injury

Neural stem cells(NSCs)in the spinal cord hold great potential for repair after spinal cord injury(SCI).The ependyma in the central canal(CC)region has been considered as the NSCs source in the spinal cord.However,the ependyma function as NSCs after SCI is still under debate.We used Nestin as a marker to isolate potential NSCs and their immediate progeny,and characterized the cells before and after SCI by single-cell RNA-sequencing(scRNA-seq).We identified two subgroups of NSCs:the subgroup located within the CC cannot prime to active NSCs after SCI,while the subgroup located outside the CC were activated and exhibited the active NSCs properties after SCI.We demonstrated the comprehensive dynamic transcriptome of NSCs from quiescent to active NSCs after SCI.This study reveals that Nestin+cells outside CC were NSCs that activated upon SCI and may thus serve as endogenous NSCs for regenerative treatment of SCI in the future.

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.

EGFR signaling augments TLR4 cell surface expression and function in macrophages via regulation of Rab5a activation

Dear Editor,oll-like receptor 4(TLR4)is a key receptor sensing bacterial lipopolysaccharide(LPS),and is the most investigated member of the Tol-like receptor family(Kawai and Akira,2007;Kayagaki et al,2013;Klein et al.,2015).Cell surface TLR4 expression is determined by the balance between receptor trafficking from the Golgi apparatus to the cell membrane,and internalization of the cell surface receptor into endosomal compartments(Saltoh,2009).In bone mar-row-derived macrophages(BMDM),we observed LPS-in-duced EGFR phosphorylation on the surface of BMDM,and this was inhibited by pretreatment with PD168393 or TAPI-1(Fig.S1).Next,we measured dynamic changes in cell sur-face TLR4 expression after LPS treatment.At6,12,and 24 h after LPS treatment,TLR4 expression on the surface of BMDM was increased^2-,~6-,and^9-fold,respectively,as compared with controls.

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.

Correction to:EGFR signaling augments TLR4 cell surface expression and function in macrophages via regulation of Rab5a activation

Figure 1.EGFR activation promotes TLR4 phosphorylation and cell surface expression of TLR4 in response to LPS.(A and B)BMDM were treated with LPS(1μg/mL)for 6,12,or 24 h in the presence or absence of pretreatment of PD or TAPI-1.(A)Flow cytometry analysis of cell surface TLR4 intensity in BMDM.(B)Flow cytometry analysis of cell surface TLR4 intensity in BMDM.(C and D)WT(C57BL76)mice were treated with LPS(10 mg/kg,i.p.).In some groups,mice were pretreated with erlotinib(100 mg/kg,gavage administration)at 30 min prior to LPS i.p.

Rare TBK1 variants in patients with frontotemporal dementia and amyotrophic lateral sclerosis in a Chinese cohort

Background:The TANK-Binding Kinase 1(TBK1)gene has recently been identified as the third or fourth most frequent cause of frontotemporal dementia(FTD)and amyotrophic lateral sclerosis(ALS).The aim of this study was to assess the genetic contribution of TBK1 in a Chinese cohort.Methods:A total of 270 cases with ALS,FTD,or their combination were recruited into this study.All the coding exons of TBK1 and intron-exon boundaries were sequenced using Sanger sequencing.The frequency of TBK1 variants and the correlation with clinical phenotypes were analyzed.Results:A novel mutation(c.1959_1960insGT,p.E653fs)was identified in a sporadic case with semantic dementia,secondarily developing ALS.Another novel variant(c.2063_2064delTT,p.L688Rfs*14)was found in an ALS-FTD family.Totally,the TBK1 variants could only account for 0.7% of cases.Conclusions:This study enlarges the genetic and phenotypic spectrum of TBK1 mutation in a Chinese cohort.Our data indicates that TBK1 mutation is not a common cause for ALS and FTD in Chinese patients.