Heterogeneous fibroblasts contribute to fibrotic scar formation after spinal cord injury in mice and monkeys.

Spinal cord injury (SCI) leads to fibrotic scar formation at the lesion site, yet the heterogeneity of fibrotic scar remains elusive. Here we show the heterogeneity in distribution, origin, and function of fibroblasts within fibrotic scars after SCI in mice and female monkeys. Utilizing lineage tracing and single-cell RNA sequencing (scRNA-seq), we found that perivascular fibroblasts (PFs), and meningeal fibroblasts (MFs), rather than pericytes/vascular smooth cells (vSMCs), primarily contribute to fibrotic scar in both transection and crush SCI. Crabp2 + /Emb+ fibroblasts (CE-F) derived from meninges primarily localize in the central region of fibrotic scars, demonstrating enhanced cholesterol synthesis and secretion of type I collagen and fibronectin. In contrast, perivascular/pial Lama1 + /Lama2+ fibroblasts (LA-F) are predominantly found at the periphery of the lesion, expressing laminin and type IV collagen and functionally involved in angiogenesis and lipid transport. These findings may provide a comprehensive understanding for remodeling heterogeneous fibrotic scars after SCI.

Harnessing developmental dynamics of spinal cord extracellular matrix improves regenerative potential of spinal cord organoids.

Neonatal spinal cord tissues exhibit remarkable regenerative capabilities as compared to adult spinal cord tissues after injury, but the role of extracellular matrix (ECM) in this process has remained elusive. Here, we found that early developmental spinal cord had higher levels of ECM proteins associated with neural development and axon growth, but fewer inhibitory proteoglycans, compared to those of adult spinal cord. Decellularized spinal cord ECM from neonatal (DNSCM) and adult (DASCM) rabbits preserved these differences. DNSCM promoted proliferation, migration, and neuronal differentiation of neural progenitor cells (NPCs) and facilitated axonal outgrowth and regeneration of spinal cord organoids more effectively than DASCM. Pleiotrophin (PTN) and Tenascin (TNC) in DNSCM were identified as contributors to these abilities. Furthermore, DNSCM demonstrated superior performance as a delivery vehicle for NPCs and organoids in spinal cord injury (SCI) models. This suggests that ECM cues from early development stages might significantly contribute to the prominent regeneration ability in spinal cord.

Effect of moxibustion on the SIRT1/FOXO3a signaling pathway in ApoE-/- mice with atherosclerosis. / 艾灸对ApoE-/-åŠ¨è„‰ç²¥æ ·ç¡¬åŒ–å°é¼ SIRT1/FOXO3a信号通路的影响.

OBJECTIVES: To observe the effects of moxibustion on blood lipid metabolism, pathological morphology of thoracic aorta, and the expression of silent information regulator 1 (SIRT1) and forkhead box transcription factor O3a (FOXO3a) in ApoE-/- atherosclerosis (AS) mice, so as to explore the potential mechanism of moxibustion in preventing and treating AS. METHODS: Ten C57BL/6J mice were fed a normal diet as the control group, and 30 ApoE-/- mice were fed a high-fat diet to establish the AS model, which were randomly divided into the model group, simvastatin group, and moxibustion group, with 10 mice in each group. From the first day of modeling, mice in the moxibustion group received mild moxibustion treatment at "Shenque"(CV8), "Yinlingquan"(SP9), bilateral "Neiguan"(PC6) and "Xuehai"(SP10) for 30 min per time；the mice in the simvastatin group were given simvastatin orally (2.5 mg·kg-1·d-1), with both treatments given once daily, 5 times a week, with a total intervention period of 12 weeks. The body weight and general condition of the mice were observed and recorded during the intervention period. After the intervention, the contents of serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured using an automated biochemistry analyzer. Hematoxylin eosin (HE) staining was used to observe the pathological morphology of the thoracic aorta. ELISA was used to measure the contents of serum oxidized low-density lipoprotein (ox-LDL) and superoxide dismutase (SOD) activity. Western blot and real-time fluorescent quantitative PCR analysis were used to detect the expression levels of SIRT1 and FOXO3a protein and mRNA in the thoracic aorta. RESULTS: Compared with the control group, body weight at the 8th and 12th week, serum TC, TG, LDL-C, and ox-LDL contents of the model group mice were significantly increased(P<0.05, P<0.01), while the HDL-C contents, SOD activity, and the expression levels of SIRT1 protein and mRNA in the thoracic aorta were significantly decreased(P<0.05, P<0.01). HE staining showed thickening of the aortic intima, endothelial cell degeneration, swelling, and shedding. Compared with the model group, body weight at the 8th and 12th week, serum TC, TG, LDL-C, and ox-LDL contents of mice in the simvastatin group and moxibustion group were significantly decreased(P<0.01), while the serum SOD activity, expression levels of SIRT1 protein and mRNA in the thoracic aorta were significantly increased(P<0.01). The HDL-C contents were significantly increased in the simvastatin group(P<0.05). The thoracic aortic structure was more intact in both groups, with a more regular lumen and orderly arrangement of the elastic membrane in the media, and a slight amount of endothelial cell degeneration and swelling in the intima. There was no significant difference in the evaluated indexes between the moxibustion group and the simvastatin group and the pathological changes in the thoracic aorta were similar between the two groups. CONCLUSIONS: Moxibustion can reduce the body weight of AS model mice, regulate lipid levels, repair vascular intima, and alleviate endothelial damage. Its mechanism of action may be related to the regulation of the SIRT1/FOXO3a signaling pathway to improve oxidative damage.

Constructing Linear-Oriented Pre-Vascularized Human Spinal Cord Tissues for Spinal Cord Injury Repair.

Repairing spinal cord injury (SCI) is a global medical challenge lacking effective clinical treatment. Developing human-engineered spinal cord tissues that can replenish lost cells and restore a regenerative microenvironment offers promising potential for SCI therapy. However, creating vascularized human spinal cord-like tissues (VSCT) that mimic the diverse cell types and longitudinal parallel structural features of spinal cord tissues remains a significant hurdle. In the present study, VSCTs are engineered using embryonic human spinal cord-derived neural and endothelial cells on linear-ordered collagen scaffolds (LOCS). Studies have shown that astrocytes and endothelial cells align along the scaffolds in VSCT, supporting axon extension from various human neurons myelinated by oligodendrocytes. After transplantation into SCI rats, VSCT survives at the injury sites and promotes endogenous neural regeneration and vascularization, ultimately reducing scarring and enhancing behavioral functional recovery. It suggests that pre-vascularization of engineered spinal cord tissues is beneficial for SCI treatment and highlights the important role of exogenous endothelial cells in tissue engineering.

Polycarbonyl polymer with zincophilic sites as protective coating for highly reversible zinc metal anodes.

The Zn anode of aqueous zinc ion batteries (AZIBs) have suffered from a series of rampant side reactions such as dendrite growth and corrosion, which seriously affect the reversibility and stability of Zn anodes. Herein, a polycarbonyl polymer poly(1,4,5,8-naphthalene tetracarboxylic anhydride anthraquinone) imine (PNAQI) as the protective coating is synthesized through a simple solvothermal method with the raw materials of the equimolar 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) and 2, 6-aminoanthraquinone (2,6-DAAQ). A series of characterizations such as contact angle measurement and ex-situ XRD analysis confirm that it can effectively prevent some side reactions. Moreover, CO on PNAQI can regulate the uniform distribution of zinc, thereby preventing the occurrence of zinc dendrites. Finally, the PNAQI@Zn//PNAQI@Zn symmetrical cell demonstrates a long cycle life exceeding 1000 h at current density of 1.0 mA cm-2 and a capacity of 1.0 mAh cm-2. The result significantly outperforms the cycling performance of the cell with bare zinc anode. Especially, the full battery of PNAQI@Zn//NH4V4O10 demonstrates an excellent capacity retention and prolonged cycle life (96.9 mAh/g after 1000 cycles at 1.0 A/g) compared to Zn//NH4V4O10. This work provides an effective, simple and low-cost solution for developing high-performance AZIBs.

3D Fast Sodium Transport Network of MoS2 Endowed by Coupling of Sulfur Vacancies and Sn Doping for Outstanding Sodium Storage.

A sulfur vacancy-rich, Sn-doped as well as carbon-coated MoS2 composite (Vs-SMS@C) is rationally synthesized via a simple hydrothermal method combined with ball-milling reduction, which enhances the sodium storage performance. Benefiting from the 3D fast Na+ transport network composed of the defective carbon coating, Mo─S─C bonds, enlarged interlayer spacing, S-vacancies, and lattice distortion in the composite, the Na+ storage kinetics is significantly accelerated. As expected, Vs-SMS@C releases an ultrahigh reversible capacity of 1089 mAh g-1 at 0.1 A g-1, higher than the theoretical capacity. It delivers a satisfactory capacity of 463 mAh g-1 at a high current density of 10 A g-1, which is the state-of-the-art rate capability compared to other MoS2 based sodium ion battery anodes to the knowledge. Moreover, a super long-term cycle stability is achieved by Vs-SMS@C, which keeps 91.6% of the initial capacity after 3000 cycles under the current density of 5 A g-1 in the voltage of 0.3-3.0 V. The sodium storage mechanism of Vs-SMS@C is investigated by employing electrochemical methods and ex situ techniques. The synergistic effect between S-vacancies and doped-Sn is evidenced by DFT calculations. This work opens new ideas for seeking excellent metal sulfide anodes.

Single-cell analysis reveals region-heterogeneous responses in rhesus monkey spinal cord with complete injury.

Spinal cord injury (SCI) leads to severe sensory and motor dysfunction below the lesion. However, the cellular dynamic responses and heterogeneity across different regions below the lesion remain to be elusive. Here, we used single-cell transcriptomics to investigate the region-related cellular responses in female rhesus monkeys with complete thoracic SCI from acute to chronic phases. We found that distal lumbar tissue cells were severely impacted, leading to degenerative microenvironments characterized by disease-associated microglia and oligodendrocytes activation alongside increased inhibitory interneurons proportion following SCI. By implanting scaffold into the injury sites, we could improve the injury microenvironment through glial cells and fibroblast regulation while remodeling spared lumbar tissues via reduced inhibitory neurons proportion and improved phagocytosis and myelination. Our findings offer crucial pathological insights into the spared distal tissues and proximal tissues after SCI, emphasizing the importance of scaffold-based treatment approaches targeting heterogeneous microenvironments.

Single-cell transcriptomics reveals ependymal subtypes related to cytoskeleton dynamics as the core driver of syringomyelia pathological development.

Syringomyelia is a common clinical lesion associated with cerebrospinal fluid flow abnormalities. By a reversible model with chronic extradural compression to mimic human canalicular syringomyelia, we explored the spatiotemporal pathological alterations during syrinx development. The most dynamic alterations were observed in ependymal cells (EPCs), oligodendrocyte lineage, and microglia, as a response to neuroinflammation. Among different cell types, EPC subtypes experienced obvious dynamic alterations, which were accompanied by ultrastructural changes involving the ependymal cytoskeleton, cilia, and dynamic injury in parenchyma primarily around the central canal, corresponding to the single-cell transcripts. After effective decompression, the syrinx resolved with the recovery of pathological damage and overall neurological function, implying that for syringomyelia in the early stage, there was still endogenous repair potential coexisting with immune microenvironment imbalance. Ependymal remodeling and cilia restoration might be important for better resolution of syringomyelia and parenchymal injury recovery.

Spinal cord tissue engineering using human primary neural progenitor cells and astrocytes.

Neural progenitor cell (NPC) transplantation is a promising approach for repairing spinal cord injury (SCI). However, cell survival, maturation and integration after transplantation are still major challenges. Here, we produced a novel centimeter-scale human spinal cord neural tissue (hscNT) construct with human spinal cord neural progenitor cells (hscNPCs) and human spinal cord astrocytes (hscAS) on a linearly ordered collagen scaffold (LOCS). The hscAS promoted hscNPC adhesion, survival and neurite outgrowth on the LOCS, to form a linearly ordered spinal cord-like structure consisting of mature neurons and glia cells. When transplanted into rats with SCI, the hscNT created a favorable microenvironment by inhibiting inflammation and glial scar formation, and promoted neural and vascular regeneration. Notably, the hscNT promoted neural circuit reconstruction and motor functional recovery. Engineered human spinal cord implants containing astrocytes and neurons assembled on axon guidance scaffolds may therefore have potential in the treatment of SCI.

Transplantation of neural stem progenitor cells from different sources for severe spinal cord injury repair in rat.

Neural stem progenitor cell (NSPC) transplantation has been regarded as a promising therapeutic method for spinal cord injury (SCI) repair. However, different NSPCs may have different therapeutic effects, and it is therefore important to identify the optimal NSPC type. In our study, we compared the transcriptomes of human fetal brain-derived NSPCs (BNSPCs), spinal cord-derived NSPCs (SCNSPCs) and H9 embryonic stem-cell derived NSPCs (H9-NSPCs) in vitro and subsequently we transplanted each NSPC type on a collagen scaffold into a T8-9 complete SCI rat model in vivo. In vitro data showed that SCNSPCs had more highly expressed genes involved in nerve-related functions than the other two cell types. In vivo, compared with BNSPCs and H9-NSPCs, SCNSPCs exhibited the best therapeutic effects; in fact, SCNSPCs facilitated electrophysiological and hindlimb functional recovery. This study demonstrates that SCNSPCs may be an appropriate candidate cell type for SCI repair, which is of great clinical significance.

Purinergic receptors mediate endothelial dysfunction and participate in atherosclerosis.

Atherosclerosis is the main pathological basis of cardiovascular disease and involves damage to vascular endothelial cells (ECs) that results in endothelial dysfunction (ED). The vascular endothelium is the key to maintaining blood vessel health and homeostasis. ED is a complex pathological process involving inflammation, shear stress, vascular tone, adhesion of leukocytes to ECs, and platelet aggregation. The activation of P2X4, P2X7, and P2Y2 receptors regulates vascular tone in response to shear stress, while activation of the A2A, P2X4, P2X7, P2Y1, P2Y2, P2Y6, and P2Y12 receptors promotes the secretion of inflammatory cytokines. Finally, P2X1, P2Y1, and P2Y12 receptor activation regulates platelet activity. These purinergic receptors mediate ED and participate in atherosclerosis. In short, P2X4, P2X7, P2Y1, and P2Y12 receptors are potential therapeutic targets for atherosclerosis.

Inflammatory Microenvironment-Responsive Nanomaterials Promote Spinal Cord Injury Repair by Targeting IRF5.

Spinal cord injury (SCI) involves excessive inflammatory responses, which are characterized by the existence of high levels of proinflammatory M1 macrophages rather than prohealing M2 macrophages, and oxidative stress. Interferon regulatory factor 5 (IRF5) is a promising therapeutic target in regulation of macrophage reprogramming from the M1 to M2 phenotype. However, knockdown of IRF5 expression mediated by small interfering RNA (siRNA) is limited by instability and poor cellular uptake. In the present study, polyethylenimine-conjugated, diselenide-bridged mesoporous silica nanoparticles are tailored to regulate macrophage polarization by controllably delivering siRNA to silence IRF5. The MSN provides reactive oxygen species (ROS)-responsive degradation and release, while polyethylenimine-function offers efficient loading of siRNA-IRF5 and enhanced endosome escape. As a consequence, the intelligent nanomaterial effectively transfects the siRNA-IRF5 with its remaining high stability and bioactivity, thereby effectively regulating the M1-to-M2 macrophage conversion in vitro and in vivo. Importantly, administration of the functional nanomaterial in crush SCI mice suppresses excessive inflammation, enhances neuroprotection, and promotes locomotor restoration. Collectively, the ROS-responsive nanomedicine provides a gene silencing strategy for regulating macrophage polarization and oxidative balance in SCI repair.

[Effect of mild moxibustion on SIRT1/NF-κB signaling in atherosclerotic rabbits].

OBJECTIVE: To observe the effect of mild moxibustion on blood lipid, histopathological structure of the aortic arch, thoracic aortic silent information regulator 1 (SIRT1)/nuclear factor κB (NF-κB) signaling pathway in atherosclerosis (AS) rabbits, so as to explore its underlying mechanisms in improving AS. METHODS: Sixty male rabbits were randomly divided into control group (n=12), model group(n=11), mild moxibustion group (n=11), mild moxibustion + blocker (blocker) group (n=12). The AS model was established by feeding the rabbits with high-fat forage for 8 weeks, followed by immune response damage. Mild moxibustion was applied to "Danzhong"(CV17), "Shenque"(CV8) and "Neiguan" (PC6, bilateral) and "Xuehai" (SP10, bilateral) for 30 min, once daily, 3 times a week for 4 weeks. Rabbits of the blocker group received intraperitoneal injection of EX527 (a selective inhibitor of SIRT1, 5 mg·kg-1·d-1) 30 min before moxibustion. Rabbits of the control and model groups were only grabbed and fixed without intervention. After the intervention, the contents of serum triglyceride (TG) and total cholesterol (TC) were determined by enzymatic method, and those of serum low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were determined by colorimetric method. The Sudan Ⅳ staining was employed to observe the histopathological structure of the aortic arch, and Western blot and fluorescence quantitative real time-PCR were used to detect the expressions of SIRT1 and NF-κB proteins and mRNAs in the thoracic aorta, respectively. RESULTS: Compared with the control group, the contents of serum TG, TC and LDL-C and the expression levels of NF-κB protein and mRNA were significantly increased (P<0.01, P<0.05), whereas the content of HDL-C and the expression of SIRT1 mRNA markedly decreased in the model group (P<0.01). After mild moxibustion, the contents of serum TG, TC, and LDL-C and the expression of NF-κB protein and mRNA were significantly down-regulated (P<0.01, P<0.05), while the content of HDL-C and the expression levels of SIRT1 protein and mRNA significantly up-regulated in the mild moxibustion group (P<0.05, P<0.01). There were no significant differences between the blocker and model groups in all the indexes (P>0.05). Compared with the mild moxibustion group, the serum TG, TC, and LDL-C contents and NF-κB protein expression were significantly increased (P<0.01, P<0.05), and HDL-C content and the expression of SIRT1 protein and mRNA significantly decreased (P<0.05, P<0.01) in the blocker group. Sudan Ⅳ staining showed vague structure of the aortic arch with obvious lipid infiltration in the model group, which was relatively milder in the mild moxibustion. CONCLUSION: Mild-moxibustion can reduce blood lipid levels and endothelial damage in atherosclerotic rabbits, which may be related to its function in regulating SIRT1/NF-κB signaling pathway.

Down-regulation of Risa improves podocyte injury by enhancing autophagy in diabetic nephropathy.

BACKGROUND: LncRNA AK044604 (regulator of insulin sensitivity and autophagy, Risa) and autophagy-related factors Sirt1 and GSK3ß play important roles in diabetic nephropathy (DN). In this study, we sought to explore the effect of Risa on Sirt1/GSK3ß-induced podocyte injury. METHODS: Diabetic db/db mice received Risa-inhibition adeno-associated virus (AAV) via tail vein injection, and intraperitoneal injection of lithium chloride (LiCl). Blood, urine, and kidney tissue samples were collected and analyzed at different time points. Immortalized mouse podocyte cells (MPCs) were cultured and treated with Risa-inhibition lentivirus (LV), EX-527, and LiCl. MPCs were collected under different stimulations as noted. The effects of Risa on podocyte autophagy were examined by qRT-PCR, Western blotting analysis, transmission electron microscopy, Periodic Acid-Schiff staining, and immunofluorescence staining. RESULTS: Risa and activated GSK3ß were overexpressed, but Sirt1 was downregulated in DN mice and high glucose-treated MPCs (P < 0.001, db/m vs. db/db, NG or HM vs. HG), which was correlated with poor prognosis. Risa overexpression attenuated Sirt1-mediated downstream autophagy levels and aggravated podocyte injury by inhibiting the expression of Sirt1 (P < 0.001, db/m vs. db/db, NG or HM vs. HG). In contrast, Risa suppression enhanced Sirt1-induced autophagy and attenuated podocyte injury, which could be abrogated by EX-527 (P < 0.001, db/db + Risa-AAV vs. db/db, HG + Risa-LV vs. HG). Furthermore, LiCl treatment could restore GSK3ß-mediated autophagy of podocytes (P < 0.001, db/db + LiCl vs. db/db, HG + LiCl vs. HG), suggesting that Risa overexpression aggravated podocyte injury by decreasing autophagy. CONCLUSION: Risa could inhibit autophagy by regulating the Sirt1/GSK3ß axis, thereby aggravating podocyte injury in DN. Risa may serve as a therapeutic target for the treatment of DN.

Dual metal ions and water molecular pre-intercalated δ-MnO2 spherical microflowers for aqueous zinc ion batteries.

Layered δ-MnO2 is a promising cathode material for aqueous zinc ion batteries (AZIBs) due to its high theoretical capacity, high operating voltage and low cost. However, the dissolution of MnO2 and the disproportionation of Mn3+ will lead to irreversible reaction and serious structural degradation of the material during cycling process. In this work, the Al3+ pre-intercalated K0.27MnO2·0.54H2O was prepared by a one-step hydrothermal method with citric acid as the complexing agent and weak reducing agent. Based on the pillars of bimetallic ions K+, Al3+ and water, the framework and interlayer of δ-MnO2 is stabilized. Besides, a certain amount of Al3+ facilitates the increase of crystal water compared with the pure K0.27MnO2·0.54H2O, which is not only conducive to promote the construction of porous and loose 3D morphology, but also beneficial to improve the stability of layered structure and accelerate the migration rate of zinc ions. Contributed to the dissolution/deposition reaction mechanism combined with H+/Zn2+ co-insertion/co-extraction mechanism, it has achieved the high capacity with the maximum reversible specific capacity of 269.5 mAh g-1 at 0.5 A g-1 and excellent stability with 205.8 mAh g-1 even after 300 cycles in Zn//Al-KMO battery.

Comparative efficacy of different types of acupuncture as adjuvant therapy on carotid atherosclerosis: a protocol for systematic review and network meta-analysis.

INTRODUCTION: Carotid atherosclerosis (CAS) is a disease of the aorta caused by lipid metabolism disorders and local inflammation. Acupuncture combined with traditional western medicine (such as aspirin or atorvastatin) for the treatment of CAS has been widely applied in clinical practice, but there is still a lack of supporting evidence for its efficacy and safety on CAS. Therefore, this systematic review and network meta-analysis (NMA) will summarise the effects of different types of acupuncture treatments on CAS, and a ranking of the therapeutic classes will also be presented, aiming to provide evidence-based medicine for its extensive clinical application. METHODS AND ANALYSIS: Systematic and NMA searches will be conducted in seven electronic databases: PubMed, EMBASE, Medline, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang Database and Chongqing VIP databases. The search time is from their inception to December 2020, regardless of language and publication type. Randomised controlled trials and controlled clinical trials that include patients with CAS receiving acupuncture therapy compared with a control group will be considered eligible. The primary outcomes include the carotid intima-media thickness and vessel plaque quantification; the secondary outcomes include the carotid plaque Crouse score, greyscale median, lipid levels, the incidence of cardiovascular events, safety and adverse events. The selection of studies, data extraction, quality assessment and risk of bias assessment will be conducted by two independent reviewers. The NMA will be analysed with Stata V.15.0, RevMan V.5.3 software and WinBUGS V.1.4.3. ETHICS AND DISSEMINATION: Ethical approval will not be required for this study as it will be based on de-identified, aggregated published data. We will publish the findings in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42020207260.

The S-shaped relationship between R&D investment and green innovation after cross-border merge and acquisition: evidence from China.

In the economic transition process, emerging markets are recognizing the importance of accessing sophisticated technologies to green innovation. After cross-border merge and acquisition (M&A), research and development (R&D) investment has become the basic condition for acquiring mature market technologies. Many studies suggest that R&D can promote green innovation. However, in the context of cross-border M&A, the relationship between R&D and green innovation is more complicated. Based on the knowledge-based view and stakeholder theory, this paper takes 230 cross-border M&A events at Chinese enterprises as samples. The conclusions show that instead of a linear relation, the influence of R&D input on green innovation performance after cross-border M&A is in an "S-shape"; the political connection and institutional distance of enterprises play a negative role in promoting the relationship between R&D input and green innovation performance after cross-border M&A.

A DAMP-scavenging, IL-10-releasing hydrogel promotes neural regeneration and motor function recovery after spinal cord injury.

Spinal cord injury (SCI) creates an inflammatory microenvironment characterized by damage-associated molecular patterns (DAMPs) and immune cell activation that exacerbate secondary damage and impair neurological recovery. Here we develop an immunoregulatory hydrogel scaffold for treating SCI that scavenges DAMPs and slowly releases the anti-inflammatory cytokine interleukin-10 (IL-10). We created this dual-functional scaffold by modifying a photocrosslinked gelatin hydrogel with the cationic, DAMP-binding polymer poly (amidoamine) and with IL-10, and compared the therapeutic activity of this scaffold with that of gelatin-only, gelatin + poly (amidoamine), and gelatin + IL-10 scaffolds in vitro and in vivo. In vitro, the dual-functional scaffold scavenged anionic DAMPs and exhibited sustained release of IL-10, reduced the proinflammatory responses of macrophages and microglia, and enhanced the neurogenic differentiation of neural stem cells. In a complete transection SCI mouse model, the injected dual-functional scaffold suppressed proinflammatory cytokine production, promoted the M2 macrophage/microglia phenotype, and led to neural regeneration and axon growth without scar formation to a greater extent than the single-function or control scaffolds. This DAMP-scavenging, IL-10-releasing scaffold provides a new strategy for promoting neural regeneration and motor function recovery following severe 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.

Lineage tracing reveals the origin of Nestin-positive cells are heterogeneous and rarely from ependymal cells after spinal cord injury.

Nestin is expressed extensively in neural stem/progenitor cells during neural development, but its expression is mainly restricted to the ependymal cells in the adult spinal cord. After spinal cord injury (SCI), Nestin expression is reactivated and Nestin-positive (Nestin+) cells aggregate at the injury site. However, the derivation of Nestin+ cells is not clearly defined. Here, we found that Nestin expression was substantially increased in the lesion edge and lesion core after SCI. Using a tamoxifen inducible CreER(T2)-loxP system, we verified that ependymal cells contribute few Nestin+ cells either to the lesion core or the lesion edge after SCI. In the lesion edge, GFAP+ astrocytes were the main cell type that expressed Nestin; they then formed an astrocyte scar. In the lesion core, Nestin+ cells expressed αSMA or Desmin, indicating that they might be derived from pericytes. Our results reveal that Nestin+ cells in the lesion core and edge came from various cell types and rarely from ependymal cells after complete transected SCI, which may provide new insights into SCI repair.