He received training as a cell biologist at Wageningen University. His Ph.D. (1991-1995) and a first postdoctoral research period (1995-1999) was on the topic of metastatic spread of melanoma cancer cells. Since 1999, he is affiliated with ACTA, the Academic Centre for Dentistry Amsterdam, University of Amsterdam and VU Amsterdam, first as a post-doc (1999-2002), later on as a research fellow from the Royal Netherlands Academy of Sciences (KNAW), 2002-2007) and as assistant professor (2007-). This career switch enabled him to study the formation of bone degrading osteoclasts from bone marrow and peripheral blood precursor cells in relation to fundamental processes and diseases that involve excessive breakdown of bone such as periodontitis and osteoporosis.