RUBICON research activities were organised in four work packages (WPs). The expected impact of the research performed in each WP is as follows:

WP1: The role of genetic factors, the circadian clock and signalling pathways in tendinopathies

Research in RUBICON WP1 has investigated several gaps in knowledge of the mechanism of tendinopathy and conditions affecting other connective tissues including arterial cartilage, ligaments, intramuscular connective tissue and intravertebral discs. The results include newly identified genes predisposing for injury, new knowledge on the regulation of important connective tissue proteins by the circadian clock, and the efficacy of treating tendinopathy with IGF-1 injections.

Results are to be exploited through non-proprietary innovations in clinical practice, sports training, physiotherapy and sleep hygiene. The eventual improvements in musculoskeletal health are likely to have a major positive impact for the working population, elite athletes, and the ageing population, and for societal/healthcare costs.

WP2: ER stress, intracellular signalling cascades and biomechanic consequences in heritable CTDs

Recent studies of rare heritable connective tissue disorders have identified several shared mechanisms, including mutant protein misfolding, Endoplasmic Reticulum (ER) stress and autophagy. WP2 results will contribute to the identification new therapeutic targets related to ER stress that should relate to multiple rare CTDs and will be attractive for exploitation in further translational research to improve treatment options.

Also in WP2, UNIVAQ have advanced their understanding of autosomal dominant osteopetrosis (ADO2), especially concerning altered vesicular trafficking and autophagy observed in ADO2 cells. The ADO2 CLCN7 mutations studied by UNIVAQ in WP2 are being targeted by a patented siRNA therapy being developed in other projects.

WP3: The role of lipocalin 2 in bone and tendon biology and biomechanics

Unloading is associated with several human conditions ranging from weightlessness in spaceflight to the very common situation of reduced movement capabilities in the elderly. The protein Lcn2 has been determined by University of L’Aquila to increase in bone osteoblasts under artificial microgravity and has been studied further in RUBICON WP3.

While these experiments found no effect of Lcn2 on tendon, data from analysis of bone cells suggests that Lcn2 could be a useful biomarker for osteoporosis that is associated with unloading conditions. Interestingly, Lcn2 is detectable in the saliva, which makes this biomarker suitable for monitoring the skeletal status in uncomfortable conditions, such as during spaceflights. This research may open new avenues for the control of disorders of injured, paralysed, ageing and bed-bound people.

WP4: Impact of ECM and oxygen tension on the interaction of osteogenesis and angiogenesis

Fracture healing is a process that heavily depends on the cooperation between osteoblasts and endothelial cells in the context of low oxygen (hypoxia). It is also known that oxygen has a major impact on the growth of blood vessels during healing.

WP4 has investigated the impact of extracellular matrix and hypoxia on bone and blood vessel formation during fracture healing, and how these processes may impact on tendinopathy. The studies performed have yielded insights in the relation of the extracellular matrix, oxygen tension and a specific molecule Mucin 1 in the interaction between bone and vessel formation as well as in the behaviour of tendon cells. This research may open up new avenues for improved treatment of fractures, tendinopathies and other connective tissue disorders.

Training and new collaborations

As a staff exchange network, the RUBICON project has an important impact from its training of 21 early stage researchers. They have conducted secondments up to 12 months in a participating laboratory, learning new skills and experiencing life in another country which will all contribute to their future career potential.

Additional exchange of 15 experienced researchers, for example post-doctoral researchers and other staff up to professor level, have also exchanged knowledge and established new collaborations. In particular, new collaborative partnerships have been formed between Hong Kong University, Manchester University, Erasmus Medical Centre and University of L’Aquila, and existing collaboration between other participants has been reinforced.

The training and new research tools obtained in RUBICON will support further ongoing research, including:
• studies of a rare recessive collagen mutation causing extreme tendon laxity at Murdoch Children’s Research Institute
• new molecular probes and in vitro culture systems for study of collagen matrix formation and chronobiology at Manchester University
• patient derived iPS cell models for further studies of metaphyseal chondrodysplasia type Schmid at Newcastle University
• a new tendon cell biobank at Erasmus Medical Centre to support further research into tendinopathy
• new models for ER stress and tissue regeneration transferred to Erasmus University Medical Centre
• preclinical development of siRNA therapy for ADO2 at University of L’Aquila
• models for the use of extracellular matrix and characterization of extracellular vesicles transferred to Hong Kong University for further studies on the disease osteogenesis imperfecta
• models to study bone formation and vessel formation transferred to University of Cape Town to study more the impact of calcification and angiogenesis in tendinopathies

RUBICON partners at their June 2016 meeting, Athens