In this paper we present a general framework, called NUCLEO, for the application of socio-constructive educational approaches in higher education. The underlying pedagogical approach relies on an adaptation model in order to improve group dynamics, as this has been identified as one of the key features in the success of collaborative learning scenarios. Students' learning strategies are analyzed considering a simplified version of Vermunt's model for learning styles. The resulting profiles provide the basis to group students in teams where each student is assigned a role according to his/her learning strategies. The result is the formation of complementary and semi-autonomous learning teams that collaborate to achieve solutions to the problems provided by the instructor. The framework is instantiated through an online multiplayer role-playing game environment, which sets a stage for the underlying collaborative problem-based learning approach. The framework has been benchmarked in different programming courses at the Complutense University of Madrid during 2007-08 and 2008-09 academic years. This work also presents the results of these experiences. (Contains 3 tables and 3 figures.)