An Up-regulation of IRF-1 After a Spinal Cord Injury: Implications for Neuronal Apoptosis

MiR-10b-5p Regulates Neuronal Autophagy and Apoptosis Induced by Spinal Cord Injury Through UBR7

This study aimed to explore the effects of miR-10b-5p on autophagy and apoptosis in neuronal cells after spinal cord injury (SCI) and the molecular mechanism. Bioinformatics was used to analyze the differentially expressed miRNAs. The expression of related genes and proteins were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blot, respectively. Cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EdU), and apoptosis was detected by flow cytometry or terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL). Coimmunoprecipitation confirmed the interaction between UBR7 and Wnt1 or Beclin1. Autophagy was detected by the dansylcadaverine (MDC). The Basso Beattie Bresnahan (BBB) score was used to evaluate motor function, and hematoxylin-eosin (H&E) and Nissl staining were used to detect spinal cord tissue repair and neuronal changes. The result shows that the expression of miR-10b-5p was downregulated in the SCI models, and transfection of a miR-10b-5p mimic inhibited neuronal cell apoptosis. MiR-10b-5p negatively regulated the expression of UBR7, and the inhibitory effect of the miR-10b-5p mimic on neuronal cell apoptosis was reversed by overexpressing UBR7. In addition, UBR7 can regulate apoptosis by affecting the Wnt/β-catenin pathway by promoting Wnt1 ubiquitination. Treatment with the miR-10b-5p mimic effectively improved motor function, inhibited neuronal cell apoptosis, and promoted spinal cord tissue repair in SCI rats. Overall, miR-10b-5p can alleviate SCI by downregulating UBR7 expression, inhibiting Wnt/β-catenin signaling pathway ubiquitination to reduce neuronal apoptosis, or inhibiting Beclin 1 ubiquitination to promote autophagy.

Effect of morroniside on the transcriptome profiles of rat in injured spinal cords

We have previously reported that morroniside promoted motor activity after spinal cord injury (SCI) in rats. However, the mechanism by which morroniside induces recovery of injured spinal cord (SC) remains unknown. In the current study, RNA sequencing (RNA-seq) was employed to evaluate changes of gene expressions at the transcriptional level of the injured spinal cords in morroniside-administrated rats. Principal component analysis, analysis of enriched Gene Ontology (GO), enrichment analyses Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and other bioinformatics analyses were executed to distinguish differentially expressed genes (DEGs). The results of RNA-seq confirmed the anti-inflammatory and anti-apoptotic effects of morroniside on injured SC tissues, and provided the basis for additional research of the mechanisms involving the protective effects of morroniside on SCI.

Systemic gene expression profiles according to pain types in individuals with chronic spinal cord injury

Pain affects most individuals with traumatic spinal cord injury (SCI). Major pain types after SCI are neuropathic or nociceptive, often experienced concurrently. Pain after SCI may be refractory to treatments and negatively affects quality of life. Previously, we analyzed whole blood gene expression in individuals with chronic SCI compared to able-bodied (AB) individuals. Most participants with SCI reported pain (N = 19/28). Here, we examined gene expression of participants with SCI by pain status. Compared to AB, participants with SCI with pain had 468 differentially expressed (DE) genes; participants without pain had 564 DE genes (FDR < 0.05). Among DE genes distinct to participants with SCI with pain, Gene Ontology Biological Process (GOBP) analysis showed upregulated genes were enriched in categories related to T cell activation or inflammation; downregulated genes were enriched in categories related to protein proteolysis and catabolism. Although most participants with pain reported multiple pain types concurrently, we performed a preliminary comparison of gene expression by worst pain problem type. Compared to AB, participants with SCI who ranked neuropathic (N = 9) as worst had one distinct DE gene (TMEM156); participants who ranked nociceptive (N = 10) as worst had 61 distinct DE genes (FDR < 0.05). In the nociceptive group, the GOBP category with the lowest P-value identified among upregulated genes was “positive regulation of T cell activation”; among downregulated genes it was “receptor tyrosine kinase binding”. An exploratory comparison of pain groups by principal components analysis also showed that the nociceptive group was enriched in T-cell related genes. A correlation analysis identified genes significantly correlated with pain intensity in the neuropathic or nociceptive groups (N = 145, 65, respectively, Pearson’s correlation r > 0.8). While this pilot study highlights challenges of identifying gene expression profiles that correlate with specific types of pain in individuals with SCI, it suggests that T-cell signaling should be further investigated in this context.

MicroRNA-22-3p alleviates spinal cord ischemia/reperfusion injury by modulating M2 macrophage polarization via IRF5

Cell death after spinal cord ischemia/reperfusion (I/R) can occur through necrosis, apoptosis, and autophagy, resulting in changes to the immune environment. However, the molecular mechanism of this immune regulation is not clear. Accumulating evidence indicates that microRNAs (miRs) play a crucial role in the pathogenesis of spinal cord I/R injury. Here, we hypothesized miR-22-3p may be involved in spinal cord I/R injury by interacting with interferon regulatory factor (IRF) 5. Rat models of spinal cord I/R injury were established by 12-min occlusion of the aortic arch followed by 48-hr reperfusion, with L_4-6 segments of spinal cord tissues collected. MiR-22-3p agomir, a lentivirus-delivered siRNA specific for IRF5, or a lentivirus expressing wild-type IRF5 was injected intrathecally to rats with I/R injury to evaluate the effects of miR-22-3p and IRF5 on hindlimb motor function. Macrophages isolated from rats were treated with miR-22-3p mimic or siRNA specific for IRF5 to evaluate their effects on macrophage polarization. The levels of IL-1β and TNF-α in spinal cord tissues were detected by ELISA. miR-22-3p was down-regulated, whereas IRF5 was up-regulated in rat spinal cord tissues following I/R. IRF5 was a target gene of miR-22-3p and could be negatively regulated by miR-22-3p. Silencing IRF5 or over-expressing miR-22-3p relieved inflammation, elevated Tarlov score, and reduced the degree of severity of spinal cord I/R injury. Increased miR-22-3p facilitated M2 polarization of macrophages and inhibited inflammation in tissues by inhibiting IRF5, thereby attenuating spinal cord I/R injury. Taken together, these results demonstrate that increased miR-22-3p can inhibit the progression of spinal cord I/R injury by repressing IRF5 in macrophages, highlighting the discovery of a promising new target for spinal cord I/R injury treatment.

IRF-1 promotes renal fibrosis by downregulation of Klotho

Although the key role of renal fibrosis in the progression of chronic kidney disease (CKD) is well known, the causes of renal fibrosis are not fully clarified. In this study, interferon regulatory factor 1 (IRF-1), a mammalian transcription factor, was highly expressed in fibrotic kidney of CKD patients. Concordantly, the expression level of IRF-1 was significantly elevated in the kidney of unilateral ureteral obstruction (UUO) and Adriamycin nephropathy (ADR) mice. In tubular epithelial cells, overexpression of IRF-1 could induce profibrotic markers expression, which accompanied by dramatic downregulation of Klotho, an important inhibitor of renal fibrosis. Luciferase reporter analysis and ChIP assay revealed that IRF-1 repressed Klotho expression by downregulation of C/EBP-β, which regulates Klotho gene transcription via directly binding to its promoter. Further investigation showed that tumor necrosis factor-alpha may be an important inducement for the increase of IRF-1 in tubular epithelial cells after UUO and genetic deletion of IRF-1 attenuated renal fibrosis in UUO mice. Hence, these findings demonstrate that IRF-1 contributes to the pathogenesis of renal fibrosis by downregulation of Klotho, and suppresses IRF-1 may be a potential therapeutic target for CKD.

Diosgenin Glucoside Protects against Spinal Cord Injury by Regulating Autophagy and Alleviating Apoptosis

Spinal cord injury (SCI) is a severe traumatic lesion of central nervous system (CNS) with only a limited number of restorative therapeutic options. Diosgenin glucoside (DG), a major bioactive ingredient of Trillium tschonoskii Max., possesses neuroprotective effects through its antioxidant and anti-apoptotic functions. In this study, we investigated the therapeutic benefit and underlying mechanisms of DG treatment in SCI. We found that in Sprague-Dawley rats with traumatic SCI, the expressions of autophagy marker Light Chain 3 (LC3) and Beclin1 were decreased with concomitant accumulation of autophagy substrate protein p62 and ubiquitinated proteins, indicating an impaired autophagic activity. DG treatment, however, significantly attenuated p62 expression and upregulated the Rheb/mTOR signaling pathway (evidenced as Ras homolog enriched in brain) due to the downregulation of miR-155-3p. We also observed significantly less tissue injury and edema in the DG-treated group, leading to appreciable functional recovery compared to that of the control group. Overall, the observed neuroprotection afforded by DG treatment warrants further investigation on its therapeutic potential in SCI.

Novel biomolecular information in rotenone-induced cellular model of Parkinson's disease

In order to uncover the remarkable pathogenic genes or molecular pathological process in Parkinson's disease (PD), we employed a microarray analysis upon the cellular PD model induced by rotenone. Compared to the control group, 2174 genes were screened out to be expressed differently in the rotenone-induced group by certain criterion. GO analysis and the pathways analysis showed the significant enrichment of genes that were associated with the biological process of cell cycle, apoptotic process, organelle fusion, mitochondrial lesion, endoplasmic reticulum stress and so on. Among these significant DE genes, some were sorted out to be involved in cell cycle and protein processing in endoplasmic reticulum. As the PPI network analysis showed, the interaction relationship of the DEGs involved in the process of protein generation in endoplasmic reticulum(ER) was clearly showed up. As a prediction, we emphasized the genes EDEM1, ATF4, TRAF2 might play central roles in the protein misfolding process during the progression of Parkinson's disease and these new-found genes might be the future research focus and therapeutic targets in PD.

Deep sequencing of the mouse lung transcriptome reveals distinct long non-coding RNAs expression associated with the high virulence of H5N1 avian influenza virus in mice

Long non-coding RNAs (lncRNAs) play multiple key regulatory roles in various biological processes. However, their function in influenza A virus (IAV) pathogenicity remains largely unexplored. Here, using next generation sequencing, we systemically compared the whole-transcriptome response of the mouse lung infected with either the highly pathogenic (A/Chicken/Jiangsu/k0402/2010, CK10) or the nonpathogenic (A/Goose/Jiangsu/k0403/2010, GS10) H5N1 virus. A total of 126 significantly differentially expressed (SDE) lncRNAs from three replicates were identified to be associated with the high virulence of CK10, whereas 94 SDE lncRNAs were related with GS10. Functional category analysis suggested that the SDE lncRNAs-coexpressed mRNAs regulated by CK10 were highly related with aberrant and uncontrolled inflammatory responses. Further canonical pathway analysis also confirmed that these targets were highly enriched for inflammatory-related pathways. Moreover, 9 lncRNAs and 17 lncRNAs-coexpressed mRNAs associated with a large number of targeted genes were successfully verified by qRT-PCR. One targeted lncRNA (NONMMUT011061) that was markedly activated and correlated with a great number of mRNAs was selected for further in-depth analysis, including predication of transcription factors, potential interacting proteins, genomic location, coding ability and construction of the secondary structure. More importantly, NONMMUT011061 was also distinctively stimulated during the highly pathogenic H5N8 virus infection in mice, suggesting a potential universal role of NONMMUT011061 in the pathogenesis of different H5 IAV. Altogether, these results provide a subset of lncRNAs that might play important roles in the pathogenesis of influenza virus and add the lncRNAs to the vast repertoire of host factors utilized by IAV for infection and persistence.

Microarray analysis of an synthetic α-synuclein induced cellular model reveals the expression profile of long non-coding RNA in Parkinson's disease

Long non-coding RNAs (lncRNAs) are a new research focus that are reported to influence the pathogenetic process of neurodegenerative disorders. To uncover new disease-associated genes and their relevant mechanisms, we carried out a gene microarray analysis based on a Parkinson's disease (PD) in vitro model induced by α-synuclein oligomers. This cellular model induced by 25 μmol/L α-synuclein oligomers has been confirmed to show the stable, transmissible neurotoxicity of α-synuclein, a typical PD pathological marker. And several differentially expressed lncRNAs and mRNAs were identified in this model, such as G046036, G030771, AC009365.4, RPS14P3, CTB-11I22.1, and G007549. Subsequent ceRNA analysis determined the potential relationships between these lncRNAs and their associated mRNAs and microRNAs. The results of the present study widen our horizon of PD susceptibility genes and provide new pathways towards efficient diagnostic biomarkers and therapeutic targets for PD.

Reprogramming Interferon Regulatory Factor Signaling in Cardiometabolic Diseases

Interferon regulatory factors (IRFs) are evolutionarily conserved proteins expressed not only in immune cells but also in other tissues and organs outside the immune system. In this review, we discuss mechanisms responsible for IRF-mediated innate immune responses and the function and mechanism of IRFs in cardiometabolic diseases. We focus on the role of IRFs in innate immunity and cardiometabolic homeostasis, and highlight reprogrammed IRF signaling.

Deletion of mammalian sterile 20-like kinase 1 attenuates neuronal loss and improves locomotor function in a mouse model of spinal cord trauma

Neuronal cell death following spinal cord injury (SCI) is an important contributor to neurological deficits. The purpose of our work was to delineate the function of mammalian sterile 20-like kinase 1 (Mst1), a pro-apoptotic kinase and key mediator of apoptotic signaling, in the pathogenesis of an experimental mouse model of SCI. Male mice received a mid-thoracic spinal contusion injury, and it was found that phosphorylation of Mst1 at the injured site was enhanced significantly following SCI. Furthermore, when compared to the wild-type controls, Mst1-deficient mice displayed improved locomotor function by increased Basso mouse scale score. Deletion of Mst1 in mice attenuated loss of motor neurons and suppressed microglial and glial activation following SCI. Deletion of Mst1 in mice reduced apoptosis via suppressing cytochrome c release and caspase-3 activation following SCI. Deletion of Mst1 attenuated mitochondrial dysfunction and increased ATP formation following SCI. Deletion of Mst1 in mice inhibited local inflammation following SCI, evidenced by reduced activities of myeloperoxidase and protein levels of TNF-α, IL-1β, and IL-6. In conclusion, the present study demonstrated that deletion of Mst1 attenuated neuronal loss and improved locomotor function in a mouse model of SCI, via preserving mitochondrial function, attenuating mitochondria-mediated apoptotic pathway, and suppressing inflammation, at least in part.