Project description:Carbon nanotubes are cylindrically-shaped carbon nanostructures, made up of layers of graphene rolled onto themselves, with diameters similar to those of neuronal processes. In the last decade, CNT have been used as biocompatible growing substrates for neuronal attachment, differentiation and growth. In the perspective of new developments in tissue engineering, and in particular in spinal cord repair strategies, based on the use of CNTs, our aim is to clarify the biophysical interactions between CNTs and spinal cord neurons, studying the development of the morphological and functional characteristics of spinal neurons grown on CNT-based interfaces. In this context, we used microarrays to show whether cultured dissociated spinal neurons show a difference in gene expression when grown in control conditions (polyornithine-covered substrates) or on CNT-based substrates. Gene expression profiling was evaluated from 3 replicates each of neurons grown on nanotubes and control conditions.
Project description:Carbon nanotubes are cylindrically-shaped carbon nanostructures, made up of layers of graphene rolled onto themselves, with diameters similar to those of neuronal processes. In the last decade, CNT have been used as biocompatible growing substrates for neuronal attachment, differentiation and growth. In the perspective of new developments in tissue engineering, and in particular in spinal cord repair strategies, based on the use of CNTs, our aim is to clarify the biophysical interactions between CNTs and spinal cord neurons, studying the development of the morphological and functional characteristics of spinal neurons grown on CNT-based interfaces. In this context, we used microarrays to show whether cultured dissociated spinal neurons show a difference in gene expression when grown in control conditions (polyornithine-covered substrates) or on CNT-based substrates.
Project description:Recent in vivo studies reported that inhaled carbon nanotube distribute in the alveolar region resulting in an acute inflammation, progressive fibrotic response and particle accumulation at the bronchoalveolar junction with low clearance. With similar biopersistence and shape as asbestos, a known lung carcinogen, growing concern has arisen for elevated risk of carbon nanotube-induced lung carcinogenesis; however few studies have evaluated long-term human health risks associated with chronic pulmonary carbon nanotube exposures compared to asbestos. To address this knowledge gap, we conducted subchronic in vitro exposures of dispersed single walled carbon nanotube, multi-walled carbon nanotube and crocidolite asbestos to human small airway epithelial cells to assess their neoplastic transformation potential. Subchronic single-, multi-walled carbon nanotube and asbestos exposures caused human lung cell neoplastic transformation exhibited by increased proliferation, anchorage-independent growth, invasion and angiogenesis. Whole genome profiling and protein expression analyses showed that carbon nanotube-induced transformation mechanism(s) was largely different from asbestos-related inflammatory signaling, suggesting specific carbon nanotube-induced carcinogenic potential. This study provides novel carbon nanotube and asbestos toxicogenomic information for risk assessment and an in vitro model to evaluate transformation potential of carbon nanotubes and other nanoparticles. Whole genome expression profiling was conducted on human immortalized small airway epithelial cells (SAEC-hTERT) following 6 month in vitro chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), ultrafine carbon black (D-UFCB), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to SurvantaM-BM-. dispersant (DISP) passage control cells. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.
Project description:Recent in vivo studies reported that inhaled carbon nanotube distribute in the alveolar region resulting in an acute inflammation, progressive fibrotic response and particle accumulation at the bronchoalveolar junction with low clearance. With similar biopersistence and shape as asbestos, a known lung carcinogen, growing concern has arisen for elevated risk of carbon nanotube-induced lung carcinogenesis; however few studies have evaluated long-term human health risks associated with chronic pulmonary carbon nanotube exposures compared to asbestos. To address this knowledge gap, we conducted subchronic in vitro exposures of dispersed single walled carbon nanotube, multi-walled carbon nanotube and crocidolite asbestos to human small airway epithelial cells to assess their neoplastic transformation potential. Subchronic single-, multi-walled carbon nanotube and asbestos exposures caused human lung cell neoplastic transformation exhibited by increased proliferation, anchorage-independent growth, invasion and angiogenesis. Whole genome profiling and protein expression analyses showed that carbon nanotube-induced transformation mechanism(s) was largely different from asbestos-related inflammatory signaling, suggesting specific carbon nanotube-induced carcinogenic potential. This study provides novel carbon nanotube and asbestos toxicogenomic information for risk assessment and an in vitro model to evaluate transformation potential of carbon nanotubes and other nanoparticles.
Project description:Spinal cord injury (SCI) is a common but devastating trauma of the central nerve system. In this study, we reprogrammed cultured spinal-cord reactive astrocytes into neurons by Neurod1 expression. The mechanism of programmed conversion from astrocytes to neurons has not been clarified yet. Thus, we used label-free proteomics to identify differentially expressed proteins in Neurod1 over-expressed astrocytes and control group. A total of 1952 proteins were identified, including 92 significantly changed proteins. Among these proteins, 8 proteins were identified as candidates involving in the process of the reprogramming, based on their biological function and fold change in the bioinformatic analysis. Our study revealed that that Neurod1 can directly reprogram cultured spinal-cord reactive astrocytes into neurons, and several proteins that could play a significant role during the neuronal reprogramming were discovered.
Project description:Summary: Spinal cord injury (SCI) is a damage to the spinal cord induced by trauma or disease resulting in a loss of mobility or feeling. SCI is characterized by a primary mechanical injury followed by a secondary injury in which several molecular events are altered in the spinal cord often resulting in loss of neuronal function. Analysis of the areas directly (spinal cord) and indirectly (raphe and sensorimotor cortex) affected by injury will help understanding mechanisms of SCI. Hypothesis: Areas of the brain primarily affected by spinal cord injury are the Raphe and the Sensorimotor cortex thus gene expression profiling these two areas might contribute understanding the mechanisms of spinal cord injury. Specific Aim: The project aims at finding significantly altered genes in the Raphe and Sensorimotor cortex following an induced moderate spinal cord injury in T9.
Project description:Malignant mesothelioma is one of the most aggressive forms of cancer known. Recent studies have shown that carbon nanotubes (CNTs) are biopersistent and induce mesothelioma in animals, but the underlying mechanisms are not known. Here, we investigate the effect of long-term exposure to CNTs on the aggressive behaviors of human pleural mesothelial cells, the primary cellular target of human lung mesothelioma. We show that sub-chronic exposure (4 month) to single- and multi-walled CNTs induced proliferation, migration and invasion of the cells similar to that observed in asbestos-exposed cells. An up-regulation of several key genes known to be important in cell invasion, notably matrix metalloproteinase-2 (MMP-2), was observed in the exposed mesothelial cells as determined by real-time PCR. Western blot and enzyme activity assays confirmed the increased expression and activity of MMP-2. Whole genome expression microarray analysis further indicated the importance of MMP-2 in the invasion gene signaling network of the exposed cells. Knockdown of MMP-2 in CNT and asbestos-exposed cells by shRNA-mediated gene silencing effectively inhibited the aggressive phenotypes. This study provides new evidence for CNT-induced cell invasion and indicates the role of MMP-2 in the process. Whole genome expression profiling was conducted on human immortalized pleural mesothelial cells (MeT5A) following 4 month in vitro sub-chronic exposure to six separate treatments to assess differences in carbon nanotube (CNT) vs. asbestos potential tumorigenesis signaling. Dispersed single wall CNT (D-SWCNT), multi-wall CNT (D-MWCNT), crocidolite asbestos (ASB) and saline (SAL) exposed cells were compared to Survanta® dispersant (DISP) passage control cells. DISP and SAL cells served as control treatments for CNT- and ASB-exposed cells, respectively. Each treatment possessed 3 biological cDNA replicates. One technical replicate was performed per biological sample.
Project description:Although axon regeneration can now be induced experimentally across anatomically complete spinal cord injury (SCI), restoring meaningful function after such injuries has been elusive. This failure contrasts with the spontaneous, naturally occuring repair that restores walking after severe but incomplete SCI. Here, we applied projection-specific and comparative single-nucleus RNA sequencing to uncover the transcriptional phenotype and connectome of neuronal subpopulations involved in natural spinal cord repair. We identified a molecularly defined population of excitatory projection neurons in the thoracic spinal cord that extend axons to the lumbar spinal cord where walking execution centers reside. We show that regrowing axons from these specific neurons across anatomically complete SCI and guiding them to reconnect with their appropriate target region in the lumbar spinal cord restores walking in mice. These results demonstrate that mechanism-based repair strategies that recapitulate the natural topology of molecularly defined neuronal subpopulations can restore neurological functions. Expanding this principle to different classes of neurons across the central nervous system may unlock the framework to achieve complete repair of the injured spinal cord.
Project description:Analysis of expression changes in prelabeled laser-microdissected thoracic propriospinal neurons at different times after low-thoracic spinal cord transection in adult rats. Propriospinal neurons projecting to the lumbar enlargement were captured at various time points following no lesion or low thoracic spinal cord transection.
Project description:Adult zebrafish have the ability to recover from spinal cord injury and exhibit re-growth of descending axons from the brainstem to the spinal cord. We performed gene expression analysis using microarray to find damage-induced genes after spinal cord injury, which shows that Sox11b mRNA is up-regulated at 11 days after injury. However, the functional relevance of Sox11b for regeneration is not known. Here, we report that the up-regulation of Sox11b mRNA after spinal cord injury is mainly localized in ependymal cells lining the central canal and in newly differentiating neuronal precursors or immature neurons. Using an in vivo morpholino-based gene knockout approach, we demonstrate that Sox11b is essential for locomotor recovery after spinal cord injury. In the injured spinal cord, expression of the neural stem cell associated gene, Nestin, and the proneural gene Ascl1a (Mash1a), which are involved in the self-renewal and cell fate specification of endogenous neural stem cells, respectively, is regulated by Sox11b. Our data indicate that Sox11b promotes neuronal determination of endogenous stem cells and regenerative neurogenesis after spinal cord injury in the adult zebrafish. Enhancing Sox11b expression to promote proliferation and neurogenic determination of endogenous neural stem cells after injury may be a promising strategy in restorative therapy after spinal cord injury in mammals. Spinal cord injury or control sham injury was performed on adult zebrafish. After 4, 12, or 264 hrs, a 5 mm segment of spinal cord was dissected and processed (as a pool from 5 animals) in three replicate groups for each time point and treatment.