Effects of BDNF and NGF on cytokine expression in immune cells
Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are members of the neurotrophin (NT) family. They have important effects on cell survival and differentiation in the nervous system.1 It is known that BDNF and NGF are also expressed by immune cells, and there is increasing evidence that there is cross-talk between the nervous and immune systems.2-4 One aim of the study described here was to learn more about possible interactions between the nervous and immune systems. Therefore, we investigated whether NGF and BDNF influence the cytokine pattern in human immune cells. Due to the recent finding that immune cells are capable of producing BDNF, it was suggested that NTs might have a neuroprotective function in inflammation.4 In the nervous system the expression of BDNF mRNA could be directly increased by cyclic adenosine monophosphate (cAMP)5 and by chronic administration of rolipram, a phosphodiesterase (PDE) inhibitor.6 Based on these data, a second aim of our study was to investigate whether BDNF production by immune cells could be increased by the PDE inhibitor pentoxiphylline (PTX), which had already been studied in patients with multiple sclerosis (MS),7 and additionally by interferon-β (IFN-β), which is one of the basic immunomodulatory treatments for MS.