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Published on: September 26, 2016
Shotgun proteomics analysis reveals new unsuspected molecular effectors of nitrogen-containing bisphosphonates in
Nicoletta Bivi1, Paola Picotti, Lukas N Müller
1Department of Medical and Biological Sciences, University of Udine, 33100 Udine, Italy.
Abstract:
Nitrogen-containing bisphosphonates (N-BPs) are therapeutic agents used to treat osteoporosis and promote osteoblast and osteocyte survival. The molecular mechanisms underlying this effect have been extensively studied, but the global changes induced by N-BPs at the protein level are not known. In this context, we investigated the effect of 10(-7)M Risedronate for 1h and 48h on MLO-Y4 osteocytic cells, through a quantitative, label free shotgun proteomic analysis. We described herein a preliminary proteome map of untreated MLO-Y4 cells, composed of 353 protein species. Moreover, we identified 10 and 15 differentially expressed proteins after 1h and 48h of Risedronate treatment, respectively. Among these, PARK7/DJ-1 protein levels were induced up to 3 times and this event was associated with the activation of the pro-survival Akt pathway that we propose as a novel player in the effect of N-BPs on osteocytes. Risedronate was also able to induce the expression and the secretion of the growth factor pro-granulin. In addition, protein prenylation inhibition appeared to be involved in the modulation of MLO-Y4 proteome by RIS in a protein-specific manner. In conclusion, these findings unveil novel functions targeted by N-BPs in osteocytes and could be useful to design novel pharmaceutical compounds.
Insights
Nitrogen-containing bisphosphonates (N-BPs) like Risedronate impact osteocyte survival by altering protein expression. This study reveals novel molecular targets, including PARK7/DJ-1 and pro-granulin, offering insights for osteoporosis drug development.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Nitrogen-containing bisphosphonates (N-BPs) are crucial for treating osteoporosis and enhancing osteocyte survival.
- While their therapeutic effects are known, the comprehensive protein-level changes induced by N-BPs remain largely uncharacterized.
Purpose of the Study:
- To investigate the global proteomic alterations in MLO-Y4 osteocytic cells following Risedronate treatment.
- To identify novel molecular mechanisms and protein targets involved in the action of N-BPs on osteocytes.
Main Methods:
- Quantitative, label-free shotgun proteomic analysis was employed.
- MLO-Y4 osteocytic cells were treated with 10(-7)M Risedronate for 1 hour and 48 hours.
- Proteomic data was analyzed to identify differentially expressed proteins and associated pathways.
Main Results:
- A preliminary proteome map of 353 protein species in untreated MLO-Y4 cells was established.
- Risedronate treatment led to the identification of 10 differentially expressed proteins at 1h and 15 at 48h.
- Key findings include a 3-fold induction of PARK7/DJ-1, activation of the Akt pathway, and increased expression/secretion of pro-granulin.
Conclusions:
- Risedronate modulates osteocyte proteome, impacting pathways like Akt signaling and inducing specific proteins such as PARK7/DJ-1 and pro-granulin.
- Protein prenylation inhibition is implicated in Risedronate's effects on osteocyte proteome.
- These findings elucidate novel functions of N-BPs in osteocytes and suggest potential avenues for developing new osteoporosis therapeutics.