Contributions
Abstract: EP1451
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Pathology
Neuropathological characteristics of multiple sclerosis (MS) are alterations in blood-brain barrier function, perivascular infiltration and migration of leukocytes, activation of local glial cells, demyelination and axonal loss.
Tissue Transglutaminase (TG2) is a multifunctional enzyme, well known for its role in cross-linking of proteins. In addition, TG2 acts as a co-receptor for β-integrins to enhance fibronectin binding. In this way TG2 is considered to facilitate cell adhesion and migration. In a previous study we observed the appearance of TG2 in MHCII positive cells in active MS lesions1. Moreover, in an experimental animal model for MS, TG2 mediated the infiltration of monocytes into the CNS1. These data prompted us to study TG2 in monocytes from MS patients with ongoing disease. Thus, in the present study we questioned whether TG2 expression is altered in monocytes from MS patients compared to control subjects? Moreover, we determined the inflammatory status of the TG2 expression cells and whether TG2 can functionally contribute to human monocyte adhesion/migration processes.
From 15 MS patients and 10 healthy control subjects, blood was drawn by vena puncture. After isolation of peripheral blood mononuclear cells, monocytes were derived by using anti-CD14 beads. RNA was isolated from the monocytes and cDNA synthesized. By using q-PCR, we observed that TG2 mRNA levels were significantly higher in monocytes derived from MS patients compared to control subjects. In addition, correlation analyses indicated that TG2-expressing cells from MS patients display a more anti-inflammatory, migratory profile. Using the human THP1 monocyte cell-line, we observed that interleukin-4 (IL-4) was a major trigger of TG2 expression in this cell type. Furthermore, knock-down of TG2 expression by lentiviral transduction of the monocytes with TG2 shRNA led to enhanced IL-1β and TNFα expression, and reduced adhesion/migration after IL-4 treatment. We suggest that TG2 is an important mediator of the IL-4-induced anti-inflammatory properties of monocytes. We propose that in monocytes of MS patients the enhanced expression of TG2 can drive them into an anti-inflammatory status. Functionally, TG2 could, at least partly, mediate the enhanced adhesion of anti-inflammatory monocytes to the CNS endothelium of MS patients. In general, this could reflect a potential protective mechanism.
1Van Strien ME et al., Brain Behaviour and Immunity 50:141-154, 2015
Email: amw.vandam@vumc.nl
Disclosure: C. Sestito declares that she has no conflict of interest. J.J.P. Brevé declares that he has no conflict of interest. J. Killestein has accepted speaker and consultancy fees from Merck, Biogen, Teva, Genzyme, Roche and Novartis. C.E. Teunissen declares that she has no conflict of interest. M.M.M. Wilhelmus declares that he has no conflict of interest. B. Drukarch declares that he has no conflict of interest. J.P. van den Elsen declares that he has no conflict of interest. A-M. van Dam declares that she has no conflict of interest.
Abstract: EP1451
Type: Poster Sessions
Abstract Category: Pathology and pathogenesis of MS - Pathology
Neuropathological characteristics of multiple sclerosis (MS) are alterations in blood-brain barrier function, perivascular infiltration and migration of leukocytes, activation of local glial cells, demyelination and axonal loss.
Tissue Transglutaminase (TG2) is a multifunctional enzyme, well known for its role in cross-linking of proteins. In addition, TG2 acts as a co-receptor for β-integrins to enhance fibronectin binding. In this way TG2 is considered to facilitate cell adhesion and migration. In a previous study we observed the appearance of TG2 in MHCII positive cells in active MS lesions1. Moreover, in an experimental animal model for MS, TG2 mediated the infiltration of monocytes into the CNS1. These data prompted us to study TG2 in monocytes from MS patients with ongoing disease. Thus, in the present study we questioned whether TG2 expression is altered in monocytes from MS patients compared to control subjects? Moreover, we determined the inflammatory status of the TG2 expression cells and whether TG2 can functionally contribute to human monocyte adhesion/migration processes.
From 15 MS patients and 10 healthy control subjects, blood was drawn by vena puncture. After isolation of peripheral blood mononuclear cells, monocytes were derived by using anti-CD14 beads. RNA was isolated from the monocytes and cDNA synthesized. By using q-PCR, we observed that TG2 mRNA levels were significantly higher in monocytes derived from MS patients compared to control subjects. In addition, correlation analyses indicated that TG2-expressing cells from MS patients display a more anti-inflammatory, migratory profile. Using the human THP1 monocyte cell-line, we observed that interleukin-4 (IL-4) was a major trigger of TG2 expression in this cell type. Furthermore, knock-down of TG2 expression by lentiviral transduction of the monocytes with TG2 shRNA led to enhanced IL-1β and TNFα expression, and reduced adhesion/migration after IL-4 treatment. We suggest that TG2 is an important mediator of the IL-4-induced anti-inflammatory properties of monocytes. We propose that in monocytes of MS patients the enhanced expression of TG2 can drive them into an anti-inflammatory status. Functionally, TG2 could, at least partly, mediate the enhanced adhesion of anti-inflammatory monocytes to the CNS endothelium of MS patients. In general, this could reflect a potential protective mechanism.
1Van Strien ME et al., Brain Behaviour and Immunity 50:141-154, 2015
Email: amw.vandam@vumc.nl
Disclosure: C. Sestito declares that she has no conflict of interest. J.J.P. Brevé declares that he has no conflict of interest. J. Killestein has accepted speaker and consultancy fees from Merck, Biogen, Teva, Genzyme, Roche and Novartis. C.E. Teunissen declares that she has no conflict of interest. M.M.M. Wilhelmus declares that he has no conflict of interest. B. Drukarch declares that he has no conflict of interest. J.P. van den Elsen declares that he has no conflict of interest. A-M. van Dam declares that she has no conflict of interest.