Gene expression signatures following nerve injury in a rat model (0.5h-9h)
ABSTRACT: We used microarrays to distinguish the gene expression differences among different time points after injury We generated L4-6 dorsal root ganglia (DRG) tissues (0.5cm) at 0.5h, 3h, 6h and 9h after sciatic nerve resection
Project description:We applied Solexa sequencing technology to identify rat microRNA genes in proximal sciatic nerve following sciatic nerve resection. Using Solexa sequencing, computational analysis and Q-PCR verification, 93 novel miRNAs in rats were discovered and identified, of which 42 novel miRNAs were first reported in proximal sciatic nerve of rat and 51 novel miRNAs were produced at days 1, 4, 7 and 14 after sciatic nerve resection. These data provide an important resource relating to the role and regulation of miRNAs for future studies relating to peripheral nerve injury and regeneration. Keywords: Small RNA sequencing 18-30 nt small RNAs from proximal sciatic nerve of 30 Thirty Sprague-Dawley (SD) rats were sequenced at one Solexa lane
Project description:We used microarrays to distinguish the gene expression differences among different time points after injury. We generated L4-6 dorsal root ganglia (DRG) tissues and proximal sciatic nerve (SN) tissues (0.5cm) at 0d, 1d, 4d, 7d and 14d after sciatic nerve resection.
Project description:We used microarrays to distinguish the gene expression differences among different time points after injury. We generated proximal sciatic nerve (SN) tissues (0.5cm) at 0h, 0.5h, 1h, 3h, 6h and 9h after sciatic nerve resection.
Project description:We applied Solexa sequencing technology to identify rat microRNA genes in dorsal root ganglia (DRGs) following sciatic nerve resection. Using Solexa sequencing, computational analysis and Q-PCR verification, 114 novel miRNAs in rats were discovered and identified, of which 52 novel miRNAs were first reported in rat DRGs and 62 novel miRNAs were produced at days 1, 4, 7 and 14 after sciatic nerve resection. These data provide an important resource relating to the role and regulation of miRNAs for future studies relating to peripheral nerve injury and regeneration. 18-30 nt small RNAs from 30 Thirty Sprague-Dawley (SD) rats were sequenced at one Solexa lane
Project description:An insulating myelin sheath ensures saltatory conduction of mechanosensory A afferents. Myelin damage results in the electrical instability of A fibers and the ability to generate pain in response to light touch/pressure (mechanical allodynia). We have hypothesized and then established that the release of T cell epitopes of myelin basic protein (MBP) enables nociceptive circuitry in myelinated fibers. Thus, mass spectrometry analysis of the rat sciatic nerve proteome followed by bioinformatics examination of the datasets revealed a loss of MBP and activation of T-helper cell signaling in the nerves undergoing chronic constriction injury (CCI). Matrix metalloproteinase-9 (MMP-9) proteolysis resulted in the MBP digest peptides, including the MBP84-104 and MBP68-86 regions, which exhibit prominent immunogenic epitopes. Myelin-forming Schwann cells and paranodal areas accumulated MHCII, MMP-9 and the degraded MBP at the sciatic nerve injury site. Administration of the immunodominant MBP84-104 and MBP68-86 peptides but not of the control peptides in a naïve rat sciatic nerve produced robust mechanical allodynia. Allodynia was accompanied by the T cell infiltration and an increase in MHCII, IL-17A and TNF- levels at the nerve injection site and the segmental ganglia. The pro-nociceptive activity of the synthetic MBP84-104 diminished in athymic nude rats lacking T cells. SB-3CT, an antagonist of MMP-9, inhibited mechanical allodynia, neuroinflammation and spinal sensitization after CCI. Collectively, our novel data implicate, for the first time, MMP-mediated cleavage of MBP and the resulting MBP digest fragments as a major cause of neuropathic pain. Gene extression profiling of total RNAs extracted from rat sciatic nerves, dorsal root ganglion and spinal cords after MBP84-104 peptide injection
Project description:Remyelination is a key step in functional nerve regeneration performed by Schwann cells (SC). We have demonstrated that matrix metalloproteinase (MMP)-9 is a major regulator of signal transduction and phenotypic switching in SCs. Herein, genome-wide transcriptional profiling, followed by Ingenuity Pathway Analysis revealed the MMP-9 signaling network and its endogenous inhibitor, TIMP-1, among the top induced genes of the injured sciatic nerve, that co-distributed with MMP-9 in myelinating SCs and the paranodal/nodal areas of myelinated fibers. Homo- and heterodimers of the active and proMMP-9 were purified from injured nerves using gelatin-sepharose. MMP-9 gene deletion increased the number of immature, GFAP+ mSC and post-mitotic cell counts that correlate with shorter myelin internodes in remyelinated fibers lacking MMP-9. MMP-9 is essential to nodal clustering of voltage-gated Na+ (Nav) channels. MMP inhibitor therapy diminished the expression of Nav 1.7 and 1.8. These data established the essential role of MMP-9 in guiding SC differentiation toward myelin production and in molecular assembly of the myelin domains. Modification of Nav channels in myelinated fibers may thus provide an important therapeutic approach for a number of facilitates regeneration and attenuated neuropathic pain. Gene expression profiling of total RNAs extracted from murine sciatic nerves, dorsal root ganglion and spinal cords at day 1 and day 5 post injury.
Project description:This study aimed to establish the expression profile of circulating microRNAs (miRNAs) during nerve allotransplantation. Experimental design Male Balb/c and C57BL/6 mice (age, 10–12 weeks; weight, 30–35 g) were purchased from BioLasco (Yi-Lan, Taiwan). The Balb/c mice served as sciatic nerve allograft donors. The C57BL/6 mice were randomized into the group of nerve allograft transplantation with FK506 treatment and the group without FK506 treatment. These species of mice were selected on the basis of disparity at the MHC locus and prior experience with reciprocal rejection of grafts between these murine strains . The mice were anesthetized by intraperitoneal injection of an anesthetic cocktail consisting of 0.1 mg/g ketamine and 0.01 mg/g xylazine. The anesthetized mice were restrained in a supine position on a heated pad to maintain the body temperature at 37°C. Under aseptic conditions, with sterile povidone/iodine preparation and 70% ethanol and sterile instruments and drapes, the skin over the proximal right hindlimb was incised, and the underlying biceps femoris muscle was bluntly dissected to expose the sciatic nerve. An established mouse sciatic nerve allotransplantation model was used. In brief, 1-cm Balb/c donor sciatic nerve grafts were transplanted in reverse orientation into 0.5-cm sciatic nerve gaps created in the recipient Balb/c mice. Tension-free repair was then performed under an operating microscope with three 11–0 nylon (Ethicon Inc., Somerville, NJ) interrupted epineurial sutures under 40X magnification. The muscle was closed with 5–0 vicryl sutures, and the skin with interrupted 5–0 nylon sutures. The animals were monitored to ensure appropriate feeding and diet after surgery. FK506 was administered subcutaneously at 1 mg/(kg-d) throughout the experimental course. At 3, 7, and 14 d after initial surgery (n = 3 animals per group at each time point), the whole blood samples were collected at the indicated times in tubes containing anticoagulant. (F)3d, (F)7d and (F)14d were used to indicate the serum samples of allotransplantation mice with FK506 immunosuppression for 3, 7, and 14 d, respectively. (N)3d, (N)7d and (N)14d were used to indicate the serum samples of allotransplantation mice without FK506 immunosuppression and sacrificed at postoperative 3, 7, and 14 d, respectively. After the whole blood samples were incubated at room temperature for 15 min, they were centrifuged at 3,000 ×g for 10 min, white blood cells were slowly removed from the corresponding layers, and the serum was extracted and stored at –80°C before processing for RNA analyses. Small RNA libraries generated from the serum of mice of above groups were analyzed using an Illumina HiSeq2000 Sequencer.