Project description:Objective: Craniofacial bone defects caused by injuries and congenital diseases are a formidable challenge to clinicians. Research has shown promise in using bone marrow mesenchymal stem cells (BM-MSCs) from limb bones for craniofacial bone regeneration; yet little is known about the potential of BM-MSCs from craniofacial bones. This study compared BM-MSCs isolated from limb and craniofacial bones in pigs, a preclinical model closely resembling humans. Design: Bone marrow was aspirated from the tibia and mandible of four-month-old pigs (n=4), followed by BM-MSC isolation, culture-expansion and confirmation by flow cytometry. Proliferation rates were compared using population doubling times. Osteogenic differentiation was evaluated by quantifying alkaline phosphatase (ALP) activity. Total mRNA was extracted from freshly isolated BM-MSCs and analyzed to compare gene expressions of tibial and mandibular BM-MSCs using an Affymetrix GeneChip porcine genome array, followed by real-time RT-PCR evaluation of two neural crest markers. Results: BM-MSCs from both locations expressed MSC markers without expression of hematopoietic markers. Mandibular BM-MSCs proliferated significantly faster than tibial BM-MSCs. Without osteogenic inducers, mandibular BM-MSC alkaline phosphatase activities were 3.3-fold greater than those of tibial origin. Microarray analysis identified 383 differentially expressed genes in mandibular and tibial BM-MSCs, including higher expression of cranial neural crest-related genes nestin and BMP-4 in mandibular BM-MSCs, a trend also confirmed by real-time RT-PCR. Among differently expressed genes, only 47 showed greater than 1.5-fold differences in expression. Conclusions: These data indicate that despite many similarities in gene expression, mandibular BM-MSCs express of number of genes differently than tibial BM-MSCs and have a phenotypic profile that may make them advantageous for craniofacial bone regeneration. Bone marrow was aspirated from the mandibular symphyseal region and the tibia of 3 pigs. Mesenchymal stem cells were isolated from the bone marrow and cultured to 80% confluence. Cells were harvested for total RNA extraction and the RNA was analyzed by Affymetrix GeneChip porcine genome array.
Project description:In this experiment we compare the effect of tibial nerve transection on gene expression within the dorsal root ganglion (DRG) of rats.
Project description:Articular and growth plate cartilage have comparable structures consisting of three distinct layers of chondrocytes, suggesting similar differentiation programs and therefore similar gene expression profiles. To address this hypothesis and to explore transcriptional changes that occur during the onset of articular and growth plate cartilage divergence, we used microdissection of 10-day-old rat proximal tibial epiphyses, microarray analysis, and bioinformatics to compare gene expression profiles in individual layers of articular and growth plate cartilage. We found that many genes that were spatially upregulated in intermediate/deep zone of articular cartilage were also spatially upregulated in resting zone of growth plate cartilage (overlap greater than expected by chance, P < 0.001). Interestingly, superficial zone of articular cartilage showed an expression profile with similarities to both proliferative and hypertrophic zones of growth plate cartilage (P < 0.001 each). Additionally, significant numbers of known proliferative zone markers (3 out of 6) and hypertrophic zone markers (27 out of 126) were spatially upregulated in superficial zone compared to intermediate/deep zone (more than expected by chance, P < 0.001 each). In conclusion, we provide evidence that intermediate/deep zone of articular cartilage has a gene expression profile more similar to resting zone of growth plate cartilage, whereas superficial zone has a gene expression profile more similar to proliferative and hypertrophic zones. 10-day-old rat proximal tibial epiphyses were manually microdissected into articular cartilage superficial (SZ) and intermediate/deep (IDZ) zones and growth plate cartilage resting zone (RZ) for total RNA extraction and hybridization on Affymetrix microarrays. We used 10-day-old animals because, at this age, the secondary ossification center has recently begun to form and divides the epiphysis into articular cartilage distally and growth plate cartilage more centrally. The 4 SZ samples were taken from animals 5-8, respectively, whereas the 4 IDZ and 4 RZ samples were each taken from animals 1-2, 3-4, 5-6, and 7-8, respectively.
Project description:Objective: Craniofacial bone defects caused by injuries and congenital diseases are a formidable challenge to clinicians. Research has shown promise in using bone marrow mesenchymal stem cells (BM-MSCs) from limb bones for craniofacial bone regeneration; yet little is known about the potential of BM-MSCs from craniofacial bones. This study compared BM-MSCs isolated from limb and craniofacial bones in pigs, a preclinical model closely resembling humans. Design: Bone marrow was aspirated from the tibia and mandible of four-month-old pigs (n=4), followed by BM-MSC isolation, culture-expansion and confirmation by flow cytometry. Proliferation rates were compared using population doubling times. Osteogenic differentiation was evaluated by quantifying alkaline phosphatase (ALP) activity. Total mRNA was extracted from freshly isolated BM-MSCs and analyzed to compare gene expressions of tibial and mandibular BM-MSCs using an Affymetrix GeneChip porcine genome array, followed by real-time RT-PCR evaluation of two neural crest markers. Results: BM-MSCs from both locations expressed MSC markers without expression of hematopoietic markers. Mandibular BM-MSCs proliferated significantly faster than tibial BM-MSCs. Without osteogenic inducers, mandibular BM-MSC alkaline phosphatase activities were 3.3-fold greater than those of tibial origin. Microarray analysis identified 383 differentially expressed genes in mandibular and tibial BM-MSCs, including higher expression of cranial neural crest-related genes nestin and BMP-4 in mandibular BM-MSCs, a trend also confirmed by real-time RT-PCR. Among differently expressed genes, only 47 showed greater than 1.5-fold differences in expression. Conclusions: These data indicate that despite many similarities in gene expression, mandibular BM-MSCs express of number of genes differently than tibial BM-MSCs and have a phenotypic profile that may make them advantageous for craniofacial bone regeneration.
Project description:Peripheral nerve injury alters the expression of hundreds of proteins in dorsal root ganglia (DRG). Targeting some of these proteins has led to successful treatments for acute pain, but not for sustained postoperative neuropathic pain. The latter may require targeting multiple proteins. Since a single microRNA (miR) can affect the expression of multiple proteins, here, we describe an approach to identify chronic neuropathic pain-relevant miRs. We used two variants of the spared nerve injury (SNI): Sural-SNI and Tibial-SNI and found distinct pain phenotypes between the two. Both models induced strong mechanical allodynia, but only Sural-SNI rats maintained strong mechanical and cold allodynia, as previously reported. In contrast, we found that Tibial-SNI rats recovered from mechanical allodynia and never developed cold allodynia. Since both models involve nerve injury, we increased the probability of identifying differentially regulated miRs that correlated with the quality and magnitude of neuropathic pain and decreased the probability of detecting miRs that are solely involved in neuronal regeneration. We found seven such miRs in L3-L5 DRG. The expression of these miRs increased in Tibial-SNI. These miRs displayed a lower level of expression in Sural-SNI, with four having levels lower than those in sham animals. Bioinformatics analysis of how these miRs could affect the expression of some ion channels supports the view that, following a peripheral nerve injury, the increase of the 7 miRs may contribute to the recovery from neuropathic pain while the decrease of four of them may contribute to the development of chronic neuropathic pain. The approach used resulted in the identification of a small number of potentially neuropathic pain relevant miRs. Additional studies are required to investigate whether manipulating the expression of the identified miRs in primary sensory neurons can prevent or ameliorate chronic neuropathic pain following peripheral nerve injuries. To identify the miRs that were differentially dysregulated between Tibial-SNI and Sural-SNI, we first performed 12 microarrays in a limited number of samples (in four individual DRGs per group: Sham, Tibial-SNI and Sural-SNI; two L3-DRG and two L4-DRG). Then, miRs identified as having differential expression were corroborated with real time qRT-PCR in RNA isolated from individual DRGs (L3, L4 and L5) derived from 4 rats per group (not presented here, but in the manuscript).
Project description:LKB1 encodes a Ser/Thr kinase and acts as an evolutionarily conserved sensor of cellular energy status in eukaryotic cells. LKB1 functions as the major upstream kinase to phosphorylate AMPK and 12 other AMPK-related kinases, which is required for their activation in many cellular contexts. Once activated, AMPK and AMPK-related kinases phosphorylate a diverse array of downstream effectors to switch on ATP-generating catabolic processes and switch off ATP-consuming anabolic processes, thus restoring energy balance during periods of energetic stress. To study the role and mechanisms of Lkb1 in the regulation of hematopoietic stem cell (HSC) biology, we performed transcriptome analysis of sorted LSK (Lin-, Sca-1+, c-Kit+) cells from Lkb1 WT and KO bone marrows at 1 day post-completing tamoxifen injection (DPI). To identify more proximal molecular effects, we chose 1 DPI due to the modest phenotypes in Lkb1 KO mice, yet documentation of efficient Lkb1 deletion in LSK cells at this very early time point. We treated Lkb1 L/L rosa26CreERT2 and Lkb1 L/L mice (C57BL/Ka-CD45.2:Thy-1.1 background) with Tamoxifen for 5 days to somatically delete Lkb1 in adult mice, and generated Lkb1 WT and KO mice. At 1 DPI, we prepared single-cell suspensions from bone marrow (from femoral and tibial bones), and stained and sorted LSK populations using FACSAria (Becton Dickinson, Mountain View, CA). The RNA was extracted from sorted LSK cells, amplified and subjected to gene profiling. The samples include 3 Lkb1 WT (Lkb1 WT 5-7) and 4 Lkb1 KO (Lkb1 KO 4-7) replicates.
Project description:WGBS on tibial nerve tissue For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODE_Data_Use_Policy_for_External_Users_03-07-14.pdf
Project description:WGBS on tibial nerve tissue For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODE_Data_Use_Policy_for_External_Users_03-07-14.pdf
Project description:Chip-Seq on tibial nerve For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODE_Data_Use_Policy_for_External_Users_03-07-14.pdf