Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? Furthermore, the gut microbiota has been implicated in epigenetic regulation of the hostM-bM-^@M-^Ys transcriptional profile. We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) to investigate the microbiota-induced transcriptional responses and their kinetics in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free 10-12 weeks old female C57Bl/6 mice and on day 1, 3, 5 and 7 after colonization, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells and their kinetics, tip and crypt fractions of ileal and colonic epithelium of germ-free 10-12 weeks old female C57Bl/6 mice before and during the time course of colonization with a normal microbiota (on days 1, 3, 5 and 7) were harvested using laser capture microdissection and probed in an extensive microarray analysis.

Project description:The mammalian gut harbors a diverse microbial community (gut microbiota) that mainly consists of bacteria. Their combined genomes (the microbiome) provide biochemical and metabolic functions that complement host physiology. Maintaining symbiosis seems to be a key requirement for health as dysbiosis is associated with the development of common diseases. Previous studies indicated that the microbiota and the hostM-bM-^@M-^Ys epithelium signal bidirectional inducing transcriptional responses to fine-tune and maintain symbiosis. However, little is known about the hostM-bM-^@M-^Ys responses to the microbiota along the length of the gut as earlier studies of gut microbial ecology mostly used either colonic or fecal samples. This is of importance as not only function and architecture of the gut varies along its length but also microbial distribution and diversity. Few recent studies have begun to investigate microbiota-induced host responses along the length of the gut. However, these reports used whole tissue samples and therefore do not allow drawing conclusions about specificity of the observed responses. Which cells in the intestinal tissue are responsible for the microbially induced response: epithelial, mesenchymal or immune cells? Where are the responding cells located? We used using extensive microarray analysis of laser capture microdissection (LCM) harvested ileal and colonic tip and crypt fractions from germ-free and conventionally-raised mice to investigate the microbiota-induced transcriptional responses in specific and well-defined cell populations of the hostM-bM-^@M-^Ys epithelium. Ileum and colon segments were dissected from germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice, washed and frozen as OCT blocks. Cryosections were prepared from these OCT blocks and tip/crypt fractions isolated using laser capture microdissection. To investigate the microbiota-induced transcriptional responses specific for specific subpopulations of intestinal epithelial cells, tip and crypt fractions of ileal and colonic epithelium of germ-free and conventionally-raised 10-12 weeks old female C57Bl/6 mice were harvested using laser capture microdissection and probed in an extensive microarray analysis.

Project description:Very little is known about how intervertebral disc (IVD) is formed or maintained. Members of the TGF-ß superfamily are secreted signaling proteins that regulate many aspects of development including cellular differentiation. We recently showed that deletion of Tgfbr2 in Col2a expressing tissue results in alterations in development of IVD annulus fibrosus. The results suggested TGF-ß has an important role in regulating development of the axial skeleton, however, the mechanistic basis of TGF-ß action in these specialized joints is not known. One of the hurdles to understanding development of IVD is a lack of known markers. To identify genes that are enriched in the developing IVD and to begin to understand the mechanism of TGF-ß action in IVD development, we undertook a global analysis of gene expression comparing gene expression profiles in developing vertebrae and IVD. We also compared expression profiles in tissues from wild type and Tgfbr2 mutant mice. Lists of IVD and vertebrae enriched genes were generated. Expression patterns for several genes were verified either through in situ hybridization or literature/ database searches resulting in a list of genes that can be used as markers of IVD. Cluster analysis using genes listed under the Gene Ontology terms multicellular organism development and pattern specification indicated that mutant IVD more closely resembled vertebrae than wild type IVD. We propose TGF-ß has two functions in IVD development: 1) to prevent chondrocyte differentiation in the presumptive IVD and 2) to promote differentiation of annulus fibrosus from sclerotome. We have identified genes that are enriched in the IVD and regulated by TGF-ß that warrant further investigation as regulators of IVD development. Thirteen samples were analyzed. This includes three biological replicates of laser captured IVD from E13.5 day control mice, three biological replicates of laser captured vertebrae from the same E13.5 day control mice, three biological relicates of laser captured vertebrae from E13.5 day Col2aCre;Tgfbr2lox/lox mice, and four biological replicates of laser captured IVD from E13.5 day Col2aCre;Tgfbr2lox/lox mice.

Project description:ALS is a uniformly fatal neurodegenerative disease in which motor neurons in the spinal cord and brain stem are selectively lost. Individual motor - groups of motor neurons innervating single muscles - show widely varying degrees of disease resistance: in the final stages of ALS, nearly all voluntary movement is lost but eye movement and eliminative and sexual functions remain relatively unimpaired. These functions are controlled by motor neurons of the oculomotor (III), trochlear (IV) and abducens (VI) nuclei in the midbrain and brainstem, and by Onuf's nucleus in the lumbosacral spinal cord, respectively. Correspondingly, in ALS autopsies the oculomotor and Onuf's nuclei are almost completely preserved. We used microarray profiling of isolated wildtype mouse motor neurons to identify genes whose expression was characteristic of both oculomotor and Onuf's nuclei but not of vulnerable lumbar spinal neurons, or vice versa. Three wild-type C57BL/6J P7 male animals were perfused with 30% sucrose, lumbosacral spinal cord and midbrain regions were rapidly recovered, embedded in OCT compound, and frozen in liquid nitrogen. 12 um-thick cryosections were mounted on RNAse-free, PEN-foil covered glass slides (Zeiss), fixed for 2 min in 100% EtOH, rinsed in 50% EtOH, stained with 1% cresyl violet for 2 min, rinsed with 50% EtOH, dehydrated in graded solutions of ethanol and air dried prior to LCM using PALM Microbeam system (Zeiss). From each animal, ~200 DL, L5, and oculomotor motor neurons were collected directly in lysis buffer. RNA was purified using Absolutely RNA, NanoPrep kit (Stratagene, La Jolla, CA). RNA integrity was assessed on the Bioanalyzer 2100 (Agilent Technologies, Santa Clara, CA). At least 1.5 ng of purified RNA was the starting material used in the WT-Ovation Pico RNA Amplification System (Nugen, San Carlos,CA) with the FL-Ovation cDNA Biotin Module V2 (Nugen) to generate labeled probe. 10 ug of biotinylated cRNA from three independent samples for each motor neuron group isolated by LCM was hybridized to on Affymetrix (Santa Clara, CA) Mouse Genome 430 2.0 Arrays. Gene ontology and pathway analysis was performed using DAVID Bioinformatics Resources 6.7 (National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD).

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Whole transcriptome analysis of laser capture microdissected tissues reveals site-specific programming of the host epithelial transcriptome by the gut microbiota

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