Dr. Paola Divieti Pajevic

Trancriptomic analysis of osteocytes exposed to microgravity

ABSTRACT:

Bone is a metabolically active tissue where old bone is continuously removed by bone-degrading cells (osteoclasts) and then replaced with new one by bone-forming cells (osteoblasts). To maintain the balance of bone degradation and formation, physical forces, such as compression, need to be applied to the bone. In the absence of loading, such as during long-term spaceflight or bed rest, this balance is lost, and bone resorption exceed bone formation with a net loss of bone mass and an increase in the risk of fracture. However, how bone senses these physical forces is not well understood. Osteocytes, the most abundant cells in adult bone, are known to respond to physical forces applied to the skeleton. Despite that, whether osteocytes can sense and respond to weightlessness in space was unknown. Our study was conducted to examine whether osteocyte can sense and respond to weightlessness. Osteocytes were grown either on earth (1 G) or in space (≈ 0 G) for 2, 4, or 6 days.  Genes that were activated or suppressed in space were analyzed using microarrays. We identified that the space environment changed gene activities that lead to the activation of glycolysis pathways. In summary, our study showed that osteocytes sense and respond to weightlessness with increasing energy production.

NARRATIVE BIOSKETCH:

Dr. Divieti Pajevic is an Associate Professor of Translational Dental Medicine and the Director of the Bone Cell Core at the Goldman School of Dental Medicine, Boston University, which is part of the NIH-NIAMS funded P30 Center for Skeletal Research.  She is also the Director of the Graduate Program in Orofacial and Skeletal Biology.  Her laboratory is interested in investigating the effects of hormones (parathyroid hormone; PTH), intracellular signaling (Gsα subunit) and mechanical forces (gravity) on osteocytes both “in vivo”, using genetically modified animal models, and “in vitro.” Her laboratory has developed several osteocytic cell one, one of which Ocy454, has been distributed to numerous laboratories in the US and outside.  Dr. Divieti Pajevic has been the Principal Investigator of several federally funded grants and she has authored more than 70 original manuscripts.