Identification of four genes and biological characteristics associated with acute spinal cord injury in rats integrated bioinformatics analysis

CCL2 Knockdown Attenuates Inflammatory Response After Spinal Cord Injury Through the PI3K/Akt Signaling Pathway: Bioinformatics Analysis and Experimental Validation

Spinal cord injury (SCI) is a common clinical problem in orthopedics with a lack of effective treatments and drug targets. In the present study, we performed bioinformatic analysis of SCI datasets GSE464 and GSE45006 in the Gene Expression Omnibus (GEO) public database and experimentally validated CCL2 expression in an animal model of SCI. This was followed by stimulation of PC-12 cells using hydrogen peroxide to construct a cellular model of SCI. CCL2 expression was knocked down using small interfering RNA (si-CCL2), and PI3K signaling pathway inhibitors and activators were used to validate and observe the changes in downstream inflammation. Through data mining, we found that the inflammatory chemokine CCL2 and PI3K/Akt signaling pathways after SCI expression were significantly increased, and after peroxide stimulation of PC-12 cells with CCL2 knockdown, their downstream cellular inflammatory factor levels were decreased. The PI3K/Akt signaling pathway was blocked by PI3K inhibitors, and the downstream inflammatory response was suppressed. In contrast, when PI3K activators were used, the inflammatory response was enhanced, indicating that the CCL2-PI3K/Akt signaling pathway plays a key role in the regulation of the inflammatory response. This study revealed that the inflammatory chemokine CCL2 can regulate the inflammatory response of PC-12 cells through the PI3K/Akt signaling pathway, and blocking the expression of the inflammatory chemokine CCL2 may be a promising strategy for the treatment of secondary injury after SCI.

Identification of the CCL2 PI3K/Akt axis involved in autophagy and apoptosis after spinal cord injury

Spinal cord injury (SCI) is a devastating neurological disease with no cure that usually results in irreversible loss of sensory and voluntary motor functions below the injury site. We conducted an in-depth bioinformatics analysis combining the gene expression omnibus spinal cord injury database and the autophagy database and found that the expression of the autophagy gene CCL2 was significantly upregulated and the PI3K/Akt/mTOR signaling pathway was activated after SCI. The results of the bioinformatics analysis were verified by constructing animal and cellular models of SCI. We then used small interfering RNA to inhibit the expression of CCL2 and PI3K to inhibit and activate the PI3K/Akt/mTOR signaling pathway; western blot, immunofluorescence, monodansylcadaverine, and cell flow techniques were used to detect the expression of key proteins involved in downstream autophagy and apoptosis. We found that when PI3K inhibitors were activated, apoptosis decreased, the levels of autophagy-positive proteins LC3-I/LC3-II and Bcl-1 increased, the levels of autophagy-negative protein P62 decreased, the levels of pro-apoptotic proteins Bax and caspase-3 decreased, the levels of the apoptosis-inhibiting protein Bcl-2 increased. In contrast, when a PI3K activator was used, autophagy was inhibited, and apoptosis was increased. This study revealed the effect of CCL2 on autophagy and apoptosis after SCI through the PI3K/Akt/mTOR signaling pathway. By blocking the expression of the autophagy-related gene CCL2, the autophagic protective response can be activated, and apoptosis can be inhibited, which may be a promising strategy for the treatment of SCI.

Specific Blood RNA Profiles in Individuals with Acute Spinal Cord Injury as Compared with Trauma Controls

Background

Spinal cord injury (SCI) is known to cause a more robust systemic inflammatory response than general trauma without CNS injury, inducing severe secondary organ damage, especially the lung and liver. Related studies are principally focused on the mechanisms underlying repair and regeneration in the injured spinal cord tissue. However, the specific mechanism of secondary injury after acute SCI is widely overlooked, compared with general trauma.

Methods

Two datasets of GSE151371 and GSE45376 related to the blood samples and spinal cord after acute SCI were selected to identify the differentially expressed genes (DEGs). In GSE151371, functional enrichment analysis on specific DEGs of blood samples was performed. And the top 15 specific hub genes were identified from intersectional genes between the specific upregulated DEGs of blood samples in GSE151371 and the upregulated DEGs of the spinal cord in GSE45376. The specific functional enrichment analysis and the drug candidates of the hub genes and the miRNAs-targeted hub genes were also analyzed and predicted.

Results

DEGs were identified, and a total of 64 specific genes were the intersection of upregulated genes of the spinal cord in GSE45376 and upregulated genes of human blood samples in GSE151371. The top 15 hub genes including HP, LCN2, DLGAP5, CEP55, HMMR, CDKN3, PRTN3, SKA3, MPO, LTF, CDC25C, MMP9, NEIL3, NUSAP1, and CD163 were calculated from the 64 specific genes. Functional enrichment analysis of the top 15 hub genes revealed inflammation-related pathways. The predicted miRNAs-targeted hub genes and drug candidates of hub genes were also performed to put forward reasonable treatment strategies.

Conclusion

The specific hub genes of acute SCI as compared with trauma without CNS injury were identified. The functional enrichment analysis of hub genes showed a specific immune response. Several predicted drugs of hub genes were also obtained. The hub genes and the predicted miRNAs may be potential biomarkers and therapeutic targets and require further validation.

Transplantation of olfactory ensheathing cells decreases local and serological monocyte chemoattractant protein 1 level during the acute phase of rat spinal cord injury

OBJECTIVES

Monocyte chemoattractant protein 1 (MCP1) is one of the most upregulated cytokines in the spinal cord and serum throughout acute spinal cord injury (SCI). Olfactory ensheathing cells (OECs) transplantation improves SCI through multiple mechanisms, including immunomodulation. Our study aimed to investigate whether OECs ameliorate acute inflammation after SCI by modulating MCP1 expression.

METHODS

We established a standardized clinically relevant contusion model using the NYU impactor. OECs were administered to the injured spinal cord via microinjection 30 minutes after injury. Rat locomotor functions were assessed by the Basso-Beattie-Bresnahan scale score. Time-course histopathological (H&E and IHC) analyses were performed to record rapid changes in acute inflammation at lesion epicenters. Serum MCP1 level was detected by ELISA assay.

RESULTS

BBB scores showed improved locomotor functional recoveries in the OECs transplantation group after SCI ( P < 0.05). Staining of H&E and CD68 illustrated that OECs transplantation attenuated inflammatory response by reducing lesion areas and infiltrating myeloid cell numbers. We further revealed significantly decreased MCP1 levels in the spinal cord and serum after OECs transplantation ( P < 0.05). Noteworthily, distinct expression levels of MCP1 were found in rats undergoing a mild injury (cord impacted from a 10-mm height) compared to the moderate injury (25-mm) group.

CONCLUSION

Our study reports that transplantation of OECs promotes locomotor functional recovery after SCI and alleviates acute inflammation by decreasing local and serological MCP1 levels. We provide preliminary evidence that MCP1 might serve as a potential biomarker to reflect the severity of SCI, which is of great interest in future studies.

Bibliometric analysis of research on gene expression in spinal cord injury

Background

Spinal cord injury (SCI) is a severe disease with motor and sensory function being destroyed, which leads to a poor prognosis and a serious financial burden. It is urgent to figure out the molecular and pathological mechanisms of SCI to develop feasible therapeutic strategies. This article aims to review documents focused on gene expression in SCI and summarize research hotspots and the development process in this field.

Methods

Publications of SCI-related studies from 2000 to 2022 were retrieved from the Web of Science Core Collection database. Biblioshiny was used to evaluate the research performance, core authors, journals and contributed countries, together with trend topics, hotspots in the field, and keyword co-occurrence analysis. Visualized images were obtained to help comprehension.

Results

Among 351 documents, it was found that the number of annual publications increased in general. The most productive country was China, followed by the United States with the highest influence and the most international cooperation. Plos One was the journal of the maximum publications, while Journal of Neuroscience was the most influential one. According to keyword co-occurrence and trend topics analysis, these articles mainly focused on molecular and pathological mechanisms as well as novel therapies for SCI. Neuropathic pain, axonal regeneration and messenger RNA are significant and promising research areas.

Conclusion

As the first bibliometric study focused on gene expression in SCI, we demonstrated the evolution of the field and provided future research directions like mechanisms and treatments of SCI with great innovativeness and clinical value. Further studies are recommended to develop more viable therapeutic methods for SCI.

Role of inflammatory factors in the etiology and treatment of recurrent implantation failure

Recurrent implantation failure (RIF) is characterized by the absence of implantation after high-grade embryos are transferred to the endometrium by at least three in vitro fertilization cycles. It is one of the most important factors contributing to reproductive failure. After numerous barriers have been overcome to obtain good-quality embryos, RIF causes extreme distress and frustration in women and couples. In recent years, significant progress has been made in understanding how inflammatory factors, which include pro-inflammatory factors, anti-inflammatory factors, chemokines, and other molecules, contribute to RIF. Immunological abnormalities, hypercoagulability, and reproductive diseases are considered potential causes of RIF. In alloimmune disorders, inflammatory factors can affect the success rate of embryo implantation by altering T helper (Th)1/Th2 and Th17/regulatory T cell ratios and causing imbalances of uterine natural killer cells and macrophages. Autoimmune disorders can also lead to RIF. Inflammatory factors also play key roles in RIF-related disorders such as hypercoagulability, chronic endometritis, adenomyosis, hydrosalpinx, and endometriosis. This review focuses on the roles of inflammatory factors in RIF, including immune factors, blood hypercoagulable states, and reproductive diseases such as chronic endometritis, adenomyosis, hydrosalpinx, and endometriosis. It also summarizes the different treatments according to the causes of RIF and discusses the efficacy of sirolimus, peripheral blood mononuclear cells, low-dose aspirin combined with low-molecular-weight heparin, blocking interleukin-22, and gonadotropin-releasing hormone agonists in the treatment of RIF.

Circular RNA Hecw1 Regulates the Inflammatory Imbalance in Spinal Cord Injury via miR-3551-3p/LRRTM1 Axis

Spinal cord injury (SCI) is a neurological disease having devastating effect and results in the development of systemic inflammation. However, the molecular mechanisms of SCI remain not entirely elucidated. This study was directed toward exploring the circ Hecw1 involved in the mechanism of lipopolysaccharide (LPS)-triggered inflammation damage in neuronal cells. The in vitro model of SCI based on PC12 cells were established with lipopolysaccharide. The cell proliferation was determined by the use of cell counting kit-8 (CCK8). The expressions of circHecw1, miR-3551-3p, and inflammatory factors were measured by quantitative real-time PCR and ELISA assay. Flow cytometry was used to assess apoptosis. Western blot analysis was performed for the purpose of determining LRRTM1 and NF-kB signaling. The expression of circ Hecw1, TNF-α, IL-6, and IL-1β in LPS-triggered PC12 cells and the expression of miR-3551-3p and IL-10 were significantly decreased. Knockdown of circHecw1 promoted proliferation and inhibited apoptosis and reduction in the inflammatory cytokine expression. Our study revealed that circHecw1 regulates SCI neuronal cell inflammation imbalance by regulating the miR-3551-3p/LRRTM1 signaling.