Abstract
Bone adaptation to mechanical loading is regulated via signal transduction by mechano-sensing osteocytes. Mineral-embedded osteocytes experience strain-induced interstitial fluid flow and fluid shear stress, and broad shifts in gene expression are key components in the signaling pathways that regulate bone turnover. RNA sequencing analysis, or RNA-Seq, enables more complete characterization of mechano-responsive transcriptome regulation than previously possible. We hypothesized that RNA-Seq of osteocytic MLO-Y4 cells reveals both expected and novel gene transcript regulation in cells previously fluid flowed and analyzed using gene microarrays. MLO-Y4 cells were flowed for 2h with 1Pa oscillating fluid shear stress and post-incubated 2h. RNA-Seq of original samples detected 55 fluid flow-regulated gene transcripts (p-corrected <0.05), the same number previously detected by microarray. However, RNA-Seq demonstrated greater dynamic range, with all 55 transcripts increased >1.5-fold or decreased <0.67-fold whereas 10 of 55 met this cut-off by microarray. Analyses were complimentary in patterns of regulation, though only 6 transcripts were significant in both RNA-Seq and microarray analyses: Cxcl5, Cxcl1, Zc3h12a, Ereg, Slc2a1, and Egln1. As part of a broad inflammatory response inferred by gene ontology analyses, we again observed greatest up-regulation of inflammatory C-X-C motif chemokines, and newly implicated HIF-1α and AMPK signaling pathways. Importantly, we detected both expected fluid flow-sensitive transcripts (e.g. Nos2 [iNOS], Ptgs2 [COX-2], Ccl7) and transcripts not previously identified as flow-sensitive, e.g. Ccl2. We found RNA-Seq advantageous over microarrays because of its greater dynamic range and ability to analyze unbiased estimation of gene expression, informing our understanding of osteocyte signaling.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.