Biology subjects

Olesen, J. B.

Publications and source records attributed to Olesen, J. B..

4 recordsLinked to original sources

bioRxiv2023

Stage-Specific Modulation of Multinucleation, Fusion and Resorption by the Long Non-coding RNA DLEU1 and miR-16 in Human Primary Osteoclasts

Osteoclasts are multinucleated cells formed through fusion of mononucleated precursors of the myeloid lineage and are the only cells that can resorb all the constituents of the bone matrix. Our goal was to investigate the role of long non-coding RNA DLEU1 and miR-16-5p in the fusion of human primary osteoclasts and their resorptive capacity. We found DLEU1 to be markedly upregulated, whereas miR-16 was significantly suppressed, during osteoclast differentiation, suggesting a potential involvement in the multinucleation process. The knockdown of DLEU1 or the overexpression of miR-16 in human primary pre-osteoclasts from male human donors (50 years or older) impaired fusion at both early and late time-points, each in distinct ways, without affecting cell viability. Time-lapse recordings confirmed the impairment of the fusion process and showed an abrogation of the phagocytic cup fusion modality, as well as a reduction of the fusion between mononucleated precursors and multinucleated osteoclasts during DLEU1 silencing. Furthermore, mass spectrometry-based quantitative proteomics revealed that the effects of DLEU1 and miR-16 on osteoclast fusion were mediated by distinct proteins and processes. Thus, both DLEU1 inhibition and/or miR-16 overexpression hinder osteoclast fusion through modulation of different mechanisms. Moreover, decreased levels of DLEU1 specifically affected the resorption speed of pit-making osteoclasts, while increased levels of miR-16 promoted bone resorption mainly through pit-formation, impairing the resorption speed of the osteoclasts making trenches and affecting their resorbed area. Taken together, these findings identify DLEU1 and miR-16 as mediators of osteoclast fusion and activity, offering potential new therapeutic targets to ameliorate bone destruction in skeletal diseases with accentuated bone deterioration.

molecular biology↗

bioRxiv2023

"Important enough to show the world": Using Authentic Research Opportunities and Micropublications to Build Students' Science Identities

Primarily undergraduate institutions (PUIs) often struggle to provide authentic research opportunities that culminate in peer-reviewed publications due to "recipe-driven" lab courses and the comprehensive body of work necessary for traditional scientific publication. However, the advent of short-form, single-figure "micropublications" has created novel opportunities for early-career scientists to make and publish authentic scientific contributions on a scale and in a timespan compatible with their training periods. The purpose of this qualitative case study is to explore the benefits accrued by eight undergraduate and masters students who participated in authentic, small-scale research projects and disseminated their work as coauthors of peer-reviewed micropublications at a PUI. In these interviews, students reported that through the process of conducting and publishing their research, they developed specific competencies: reading scientific literature, proposing experiments, and collecting/interpreting publication-worthy data. Further, they reported this process enabled them to identify as contributing members of the greater scientific community.

scientific communication and education↗

bioRxiv2022

Lipid Biosynthesis Perturbation Impairs Endoplasmic Reticulum-Associated Degradation

The relationship between lipid homeostasis and protein homeostasis (proteostasis) is complex and remains incompletely understood. We conducted a screen for genes required for efficient degradation of Deg1-Sec62, a model aberrant translocon-associated substrate of the endoplasmic reticulum (ER) ubiquitin ligase Hrd1, in Saccharomyces cerevisiae. This screen revealed that INO4 is required for efficient Deg1-Sec62 degradation. INO4 encodes one subunit of the Ino2/Ino4 heterodimeric transcription factor, which regulates expression of genes required for lipid biosynthesis. Deg1-Sec62 degradation was also impaired by mutation of genes encoding several enzymes mediating phospholipid and sterol biosynthesis. The degradation defect in ino4{Delta} yeast was rescued by supplementation with metabolites whose synthesis and uptake are mediated by Ino2/Ino4 targets. Stabilization of a panel of substrates of the Hrd1 and Doa10 ER ubiquitin ligases by INO4 deletion indicates ER protein quality control is generally sensitive to perturbed lipid homeostasis. Further, loss of INO4 sensitized yeast to proteotoxic stress, suggesting a broad requirement for lipid homeostasis in maintaining proteostasis. Abundance of the ER ubiquitin-conjugating enzyme Ubc7 was reduced in the absence of INO4, consistent with a model whereby perturbed lipid biosynthesis alters the abundance of critical protein quality control mediators, with broad consequences for ER proteostasis. A better understanding of the dynamic relationship between lipid homeostasis and proteostasis may lead to improved understanding and treatment of several human diseases associated with altered lipid biosynthesis.

cell biology↗

bioRxiv2022

GIP receptor reduces osteoclast activity and improves osteoblast survival by activating multiple signaling pathways

Bone is a dynamic tissue that is remodeled throughout life by bone resorbing osteoclasts and bone forming osteoblasts, to adapt to physiological or mechanical demands. These processes are impaired in osteoporosis, and understanding how bone remodeling is regulated could improve anti-osteoporotic treatments. Clinical investigations show that short-term treatment with glucose-dependent insulinotropic polypeptide (GIP) acutely decreases serum markers of bone resorption and may increase bone formation. However, evidence for direct effects of GIP intracellular signaling and functions in mature human osteoclasts and osteoblasts have not been investigated. We report that the GIP receptor (GIPR) is robustly expressed in mature human osteoclasts. Exposure of osteoclasts to GIP inhibits osteoclastogenesis, delays bone resorption, and increases osteoclast apoptosis by acting upon multiple signaling pathways (cAMP, Src, Akt, calcium, p38) to impair nuclear translocation of nuclear factor of activated T cells 1 (NFATc1) and nuclear factor-{kappa}B (NF{kappa}B). Human osteoblasts also express GIPR, and GIP improves osteoblast survival via cAMP and Akt-mediated pathways. GIP treatment of co-cultures of osteoclasts and osteoblasts also decreased bone resorption. Antagonizing GIPR with GIP(3-30)NH2 abolished the effects of GIP on osteoclasts and osteoblasts. This study demonstrates that GIP inhibits bone resorption and improves survival of human osteoblasts, which could increase bone mass and strength, supporting clinical investigations of the effect of GIP on bone. Moreover, this study demonstrates that GIPR agonism could be beneficial in the treatment of disorders of bone remodeling, such as osteoporosis. One-sentence SummaryGIP acts directly on bone cells to regulate bone remodeling

cell biology↗