Progranulin deficiency exacerbates spinal cord injury by promoting neuroinflammation and cell apoptosis in mice

Abstract Purpose Spinal cord injury (SCI) often results in significant and catastrophic dysfunction and disability and imposes a huge economic burden on society. This study aimed to determine whether progranulin (PGRN) plays a role in the progressive damage following SCI and evaluate the potential for development of a PGRN derivative as a new therapeutic target in SCI. Methods PGRN-deficient (Gr−/−) and wild-type (WT) littermate mice were subjected to SCI using a weight-drop technique. Local PGRN expression following injury was evaluated by Western blotting and immunofluorescence. Basso Mouse Scale (BMS), inclined grid walking test, and inclined plane test were conducted at indicated time points to assess neurological recovery. Inflammation and apoptosis were examined by histology (Hematoxylin and Eosin (H&E) staining and Nissl staining, TUNEL assays, and immunofluorescence), Western blotting (from whole tissue protein for iNOS/p-p65/Bax/Bcl-2), and ex vivo ELISA (for TNFα/IL-1β/IL-6/IL-10). To identify the prophylactic and therapeutic potential of targeting PGRN, a PGRN derived small protein, Atsttrin, was conjugated to PLGA-PEG-PLGA thermosensitive hydrogel and injected into intrathecal space prior to SCI. BMS was recorded for neurological recovery and Western blotting was applied to detect the inflammatory and apoptotic proteins. Results After SCI, PGRN was highly expressed in activated macrophage/microglia and peaked at day 7 post-injury. Grn−/− mice showed a delayed neurological recovery after SCI at day 21, 28, 35, and 42 post-injury relative to WT controls. Histology, TUNEL assay, immunofluorescence, Western blotting, and ELISA all indicated that Grn−/− mice manifested uncontrolled and expanded inflammation and apoptosis. Administration of control-released Atsttrin could improve the neurological recovery and the pro-inflammatory/pro-apoptotic effect of PGRN deficiency. Conclusion PGRN deficiency exacerbates SCI by promoting neuroinflammation and cellular apoptosis, which can be alleviated by Atsttrin. Collectively, our data provide novel evidence of using PGRN derivatives as a promising therapeutic approach to improve the functional recovery for patients with spinal cord injury.

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Bazedoxifene, a Selective Estrogen Receptor Modulator, Promotes Functional Recovery in a Spinal Cord Injury Rat Model

International Journal of Molecular Sciences ◽

10.3390/ijms222011012 ◽

2021 ◽

Vol 22 (20) ◽

pp. 11012

Author(s):

Yiyoung Kim ◽

Eun Ji Roh ◽

Hari Prasad Joshi ◽

Hae Eun Shin ◽

Hyemin Choi ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Therapeutic Potential ◽

Raw 264.7 Cells ◽

Raw 264.7 ◽

Sprague Dawley ◽

Post Injury ◽

Static Compression ◽

Cord Injury

In research on various central nervous system injuries, bazedoxifene acetate (BZA) has shown two main effects: neuroprotection by suppressing the inflammatory response and remyelination by enhancing oligodendrocyte precursor cell differentiation and oligodendrocyte proliferation. We examined the effects of BZA in a rat spinal cord injury (SCI) model. Anti-inflammatory and anti-apoptotic effects were investigated in RAW 264.7 cells, and blood-spinal cord barrier (BSCB) permeability and angiogenesis were evaluated in a human brain endothelial cell line (hCMEC/D3). In vivo experiments were carried out on female Sprague Dawley rats subjected to moderate static compression SCI. The rats were intraperitoneally injected with either vehicle or BZA (1mg/kg pre-SCI and 3mg/kg for 7 days post-SCI) daily. BZA decreased the lipopolysaccharide-induced production of proinflammatory cytokines and nitric oxide in RAW 264.7 cells and preserved BSCB disruption in hCMEC/D3 cells. In the rats, BZA reduced caspase-3 activity at 1 day post-injury (dpi) and suppressed phosphorylation of MAPK (p38 and ERK) at dpi 2, hence reducing the expression of IL-6, a proinflammatory cytokine. BZA also led to remyelination at dpi 20. BZA contributed to improvements in locomotor recovery after compressive SCI. This evidence suggests that BZA may have therapeutic potential to promote neuroprotection, remyelination, and functional outcomes following SCI.

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Trehalose Augments Neuron Survival and Improves Recovery from Spinal Cord Injury via mTOR-Independent Activation of Autophagy

Oxidative Medicine and Cellular Longevity ◽

10.1155/2021/8898996 ◽

2021 ◽

Vol 2021 ◽

pp. 1-18

Author(s):

Kailiang Zhou ◽

Huanwen Chen ◽

Huazi Xu ◽

Xiaofeng Jia

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Functional Recovery ◽

Therapeutic Potential ◽

Neurological Dysfunction ◽

Tissue Loss ◽

Compression Injury ◽

Autophagy Flux ◽

Nissl Staining ◽

Cord Injury

Spinal cord injury (SCI) is a major cause of irreversible nerve injury and leads to serious tissue loss and neurological dysfunction. Thorough investigation of cellular mechanisms, such as autophagy, is crucial for developing novel and effective therapeutics. We administered trehalose, an mTOR-independent autophagy agonist, in SCI rats suffering from moderate compression injury to elucidate the relationship between autophagy and SCI and evaluate trehalose’s therapeutic potential. 60 rats were divided into 4 groups and were treated with either control vehicle, trehalose, chloroquine, or trehalose + chloroquine 2 weeks prior to administration of moderate spinal cord crush injury. 20 additional sham rats were treated with control vehicle. H&E staining, Nissl staining, western blot, and immunofluorescence studies were conducted to examine nerve morphology and quantify autophagy and mitochondrial-dependent apoptosis at various time points after surgery. Functional recovery was assessed over a period of 4 weeks after surgery. Trehalose promotes autophagosome recruitment via an mTOR-independent pathway, enhances autophagy flux in neurons, inhibits apoptosis via the intrinsic mitochondria-dependent pathway, reduces lesion cavity expansion, decreases neuron loss, and ultimately improves functional recovery following SCI (all p < 0.05 ). Furthermore, these effects were diminished upon administration of chloroquine, an autophagy flux inhibitor, indicating that trehalose’s beneficial effects were due largely to activation of autophagy. This study presents new evidence that autophagy plays a critical neuroprotective and neuroregenerative role in SCI, and that mTOR-independent activation of autophagy with trehalose leads to improved outcomes. Thus, trehalose has great translational potential as a novel therapeutic agent after SCI.

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Pharmacological Management of Acute Spinal Cord Injury: A longitudinal multi-cohort observational study

10.1101/2021.05.28.21257947 ◽

2021 ◽

Author(s):

Catherine R Jutzeler ◽

Lucie Bourguignon ◽

Bobo Tong ◽

Elias Ronca ◽

Eric Bailey ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Cohort Study ◽

Neurological Recovery ◽

Post Injury ◽

Pharmacological Management ◽

Cord Injury ◽

Observational Cohort ◽

Pharmacologic Agents ◽

High Degree

Background: Nearly every individual sustaining traumatic spinal cord injury receives multiple types and classes of medications to manage a litany of secondary complications. Prior clinical studies and evidence from animal models suggest that several of these medications could enhance or impede endogenous neurological recovery. However, there is a knowledge gap surrounding the spectrum of pharmacologic agents typically administered in the routine management of spinal cord injury. Objective: To systematically determine the types of medications commonly administered, alone or in combination, in the acute to subacute phase of spinal cord injury. Methods: We conducted an analysis of two largescale cohorts (the Sygen interventional trial and the SCIRehab observational cohort study) to determine what constitutes 'standards of acute pharmacological care' after spinal cord injury. Concomitant medication use, including dosage, timing and reason for administration, was tracked. Descriptive statistics were used to describe the medications administered within the first 60 days after spinal cord injury. Results: Across 2040 individuals with spinal cord injury, 775 unique medications were administered within the two months after injury. On average, patients enrolled in the Sygen trial received 9.9 +/- 4.9 (range 0-34), 14.3 +/- 6.3 (range 1-40), 18.6 +/- 8.2 (range 0-58), and 21.5 +/- 9.7 (range 0-59) medications within the first 7, 14, 30, and 60 days post-injury, respectively. Patients enrolled in the SCIRehab cohort study received on average 1.7 +/- 1.7 (range 0-11), 3.7 +/- 3.7 (range 0-24), 8.5 +/- 6.3 (range 0-42), and 13.5 +/- 8.3 (range 0-52) medications within the first 7, 14, 30, and 60 days post-injury, respectively. Polypharmacy was commonplace (up to 43 medications per day per patient). Approximately 10% of medications were administered acutely as prophylaxis (e.g., against the development of pain or infections). Conclusions: To our knowledge, this was the first time acute pharmacological practices have been comprehensively examined after spinal cord injury. Our study revealed a high degree of polypharmacy in the acute stages of spinal cord injury, with potential to both positively and negatively impact neurological recovery. This data may provide key insight to achieve better understanding of how the acute pharmacological management of spinal cord injury affects long-term recovery. All results can be interactively explored on the RXSCI web site (https://jutzelec.shinyapps.io/RxSCI/) and GitHub repository (https://github.com/jutzca/Acute-Pharmacological-Treatment-in-SCI/).

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Therapeutic Potential of Niche-Specific Mesenchymal Stromal Cells for Spinal Cord Injury Repair

Cells ◽

10.3390/cells10040901 ◽

2021 ◽

Vol 10 (4) ◽

pp. 901

Author(s):

Susan L. Lindsay ◽

Susan C. Barnett

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Stromal Cells ◽

Therapeutic Strategy ◽

Therapeutic Potential ◽

Ex Vivo ◽

Biological Properties ◽

Cord Injury

The use of mesenchymal stem/stromal cells (MSCs) for transplant-mediated repair represents an important and promising therapeutic strategy after spinal cord injury (SCI). The appeal of MSCs has been fuelled by their ease of isolation, immunosuppressive properties, and low immunogenicity, alongside the large variety of available tissue sources. However, despite reported similarities in vitro, MSCs sourced from distinct tissues may not have comparable biological properties in vivo. There is accumulating evidence that stemness, plasticity, immunogenicity, and adaptability of stem cells is largely controlled by tissue niche. The extrinsic impact of cellular niche for MSC repair potential is therefore important, not least because of its impact on ex vivo expansion for therapeutic purposes. It is likely certain niche-targeted MSCs are more suited for SCI transplant-mediated repair due to their intrinsic capabilities, such as inherent neurogenic properties. In addition, the various MSC anatomical locations means that differences in harvest and culture procedures can make cross-comparison of pre-clinical data difficult. Since a clinical grade MSC product is inextricably linked with its manufacture, it is imperative that cells can be made relatively easily using appropriate materials. We discuss these issues and highlight the importance of identifying the appropriate niche-specific MSC type for SCI repair.

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Stem Cell Transplantation: A Promising Therapy for Spinal Cord Injury

Current Stem Cell Research & Therapy ◽

10.2174/1574888x14666190823144424 ◽

2020 ◽

Vol 15 (4) ◽

pp. 321-331 ◽

Cited By ~ 2

Author(s):

Zhe Gong ◽

Kaishun Xia ◽

Ankai Xu ◽

Chao Yu ◽

Chenggui Wang ◽

...

Keyword(s):

Spinal Cord ◽

Stem Cells ◽

Spinal Cord Injury ◽

Stem Cell ◽

Stem Cell Transplantation ◽

Cell Transplantation ◽

Therapeutic Potential ◽

Embryonic Stem ◽

Current Status ◽

Cord Injury

Spinal Cord Injury (SCI) causes irreversible functional loss of the affected population. The incidence of SCI keeps increasing, resulting in huge burden on the society. The pathogenesis of SCI involves neuron death and exotic reaction, which could impede neuron regeneration. In clinic, the limited regenerative capacity of endogenous cells after SCI is a major problem. Recent studies have demonstrated that a variety of stem cells such as induced Pluripotent Stem Cells (iPSCs), Embryonic Stem Cells (ESCs), Mesenchymal Stem Cells (MSCs) and Neural Progenitor Cells (NPCs) /Neural Stem Cells (NSCs) have therapeutic potential for SCI. However, the efficacy and safety of these stem cellbased therapy for SCI remain controversial. In this review, we introduce the pathogenesis of SCI, summarize the current status of the application of these stem cells in SCI repair, and discuss possible mechanisms responsible for functional recovery of SCI after stem cell transplantation. Finally, we highlight several areas for further exploitation of stem cells as a promising regenerative therapy of SCI.

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Intravital Assessment of Cells Responses to Conducting Polymer-Coated Carbon Microfibres for Bridging Spinal Cord Injury

Cells ◽

10.3390/cells10010073 ◽

2021 ◽

Vol 10 (1) ◽

pp. 73

Author(s):

Bilal El Waly ◽

Vincent Escarrat ◽

Jimena Perez-Sanchez ◽

Jaspreet Kaur ◽

Florence Pelletier ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Immune Cell ◽

Two Photon ◽

Sensory Axons ◽

Promising Therapeutic Approach ◽

Cord Injury ◽

Biochemical Signals ◽

Coated Carbon ◽

Striking Effect

The extension of the lesion following spinal cord injury (SCI) poses a major challenge for regenerating axons, which must grow across several centimetres of damaged tissue in the absence of ordered guidance cues. Biofunctionalized electroconducting microfibres (MFs) that provide biochemical signals, as well as electrical and mechanical cues, offer a promising therapeutic approach to help axons overcome this blind journey. We used poly(3,4-ethylenedioxythiophene)-coated carbon MFs functionalized with cell adhesion molecules and growth factors to bridge the spinal cord after a partial unilateral dorsal quadrant lesion (PUDQL) in mice and followed cellular responses by intravital two-photon (2P) imaging through a spinal glass window. Thy1-CFP//LysM-EGFP//CD11c-EYFP triple transgenic reporter animals allowed real time simultaneous monitoring of axons, myeloid cells and microglial cells in the vicinity of the implanted MFs. MF biocompatibility was confirmed by the absence of inflammatory storm after implantation. We found that the sprouting of sensory axons was significantly accelerated by the implantation of functionalized MFs after PUDQL. Their implantation produced better axon alignment compared to random and misrouted axon regeneration that occurred in the absence of MF, with a most striking effect occurring two months after injury. Importantly, we observed differences in the intensity and composition of the innate immune response in comparison to PUDQL-only animals. A significant decrease of immune cell density was found in MF-implanted mice one month after lesion along with a higher ratio of monocyte-derived dendritic cells whose differentiation was accelerated. Therefore, functionalized carbon MFs promote the beneficial immune responses required for neural tissue repair, providing an encouraging strategy for SCI management.

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D-dopachrome tautomerase activates COX2/PGE2 pathway of astrocytes to mediate inflammation following spinal cord injury

Journal of Neuroinflammation ◽

10.1186/s12974-021-02186-z ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Huiyuan Ji ◽

Yuxin Zhang ◽

Chen Chen ◽

Hui Li ◽

Bingqiang He ◽

...

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Signal Pathways ◽

Post Injury ◽

Dopachrome Tautomerase ◽

Protein Levels ◽

Cytokines And Chemokines ◽

Cord Injury ◽

Mitogen Activated Protein ◽

Spinal Cord Contusion

Abstract Background Astrocytes are the predominant glial cell type in the central nervous system (CNS) that can secrete various cytokines and chemokines mediating neuropathology in response to danger signals. D-dopachrome tautomerase (D-DT), a newly described cytokine and a close homolog of macrophage migration inhibitory factor (MIF) protein, has been revealed to share an overlapping function with MIF in some ways. However, its cellular distribution pattern and mediated astrocyte neuropathological function in the CNS remain unclear. Methods A contusion model of the rat spinal cord was established. The protein levels of D-DT and PGE2 synthesis-related proteinase were assayed by Western blot and immunohistochemistry. Primary astrocytes were stimulated by different concentrations of D-DT in the presence or absence of various inhibitors to examine relevant signal pathways. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. Results D-DT was inducibly expressed within astrocytes and neurons, rather than in microglia following spinal cord contusion. D-DT was able to activate the COX2/PGE2 signal pathway of astrocytes through CD74 receptor, and the intracellular activation of mitogen-activated protein kinases (MAPKs) was involved in the regulation of D-DT action. The selective inhibitor of D-DT was efficient in attenuating D-DT-induced astrocyte production of PGE2 following spinal cord injury, which contributed to the improvement of locomotor functions. Conclusion Collectively, these data reveal a novel inflammatory activator of astrocytes following spinal cord injury, which might be beneficial for the development of anti-inflammation drug in neuropathological CNS.

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Spinal Cord Injury Increases Pro-inflammatory Cytokine Expression in Kidney at Acute and Sub-chronic Stages

Inflammation ◽

10.1007/s10753-021-01507-x ◽

2021 ◽

Author(s):

Shangrila Parvin ◽

Clintoria R. Williams ◽

Simone A. Jarrett ◽

Sandra M. Garraway

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Inflammatory Response ◽

Inflammatory Cytokine ◽

Cardiovascular Health ◽

Mrna Levels ◽

Post Injury ◽

Cord Injury ◽

And Function ◽

The Impact

Abstract— Accumulating evidence supports that spinal cord injury (SCI) produces robust inflammatory plasticity. We previously showed that the pro-inflammatory cytokine tumor necrosis factor (TNF)α is increased in the spinal cord after SCI. SCI also induces a systemic inflammatory response that can impact peripheral organ functions. The kidney plays an important role in maintaining cardiovascular health. However, SCI-induced inflammatory response in the kidney and the subsequent effect on renal function have not been well characterized. This study investigated the impact of high and low thoracic (T) SCI on C-fos, TNFα, interleukin (IL)-1β, and IL-6 expression in the kidney at acute and sub-chronic timepoints. Adult C57BL/6 mice received a moderate contusion SCI or sham procedures at T4 or T10. Uninjured mice served as naïve controls. mRNA levels of the proinflammatory cytokines IL-1β, IL-6, TNFα, and C-fos, and TNFα and C-fos protein expression were assessed in the kidney and spinal cord 1 day and 14 days post-injury. The mRNA levels of all targets were robustly increased in the kidney and spinal cord, 1 day after both injuries. Whereas IL-6 and TNFα remained elevated in the spinal cord at 14 days after SCI, C-fos, IL-6, and TNFα levels were sustained in the kidney only after T10 SCI. TNFα protein was significantly upregulated in the kidney 1 day after both T4 and T10 SCI. Overall, these results clearly demonstrate that SCI induces robust systemic inflammation that extends to the kidney. Hence, the presence of renal inflammation can substantially impact renal pathophysiology and function after SCI.

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