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Updated: May 3, 2026
Mouse Models for Graft Arteriosclerosis
Published on: May 14, 2013
Attenuated cardiac allograft vasculopathy in mice with targeted deletion of the transcription factor STAT4
J Koglin1, T Glysing-Jensen, S Gadiraju
1Cardiovascular Biology Laboratory, Harvard School of Public Health, Boston, MA, USA. joerg.koglin@med1.uni-muenchen.de
Background:
To study transcription factor signaling pathways that mediate cardiac allograft vasculopathy, we used mice with targeted gene deletion of signal transducer and activator of transcription (STAT)4 and STAT6 as recipients in our mouse cardiac transplant model of chronic rejection.
Methods And Results:
At day 55 after transplantation, cardiac grafts placed into STAT4 -/- (n=10) had reduced frequency (24+/-2%) and severity (9+/-4%) of vascular occlusion compared with wild-type controls (n=7, frequency 70+/-12% [P<0.001], severity 25+/-6% [P<0.05]). This decrease was associated with reduced intragraft expression ((32)P RT-PCR and immunohistochemistry) of the Th1 signature cytokines interferon-gamma (P<0.001) and interleukin (IL)-2 (P<0.001). Furthermore, cardiac grafts in STAT4 -/- had fewer infiltrating CD45(+) mononuclear cells (99+/-27 cells/mm(3) compared with 551+/-168 cells/mm(3) in wild-type controls [P<0.05]) and reduced expression of P-selectin (P<0.001) and E-selectin (P<0.01) ligand, recently shown to regulate Th1 cell recruitment. In contrast, in grafts placed into STAT6 -/- (n=11), the development of cardiac allograft vasculopathy (frequency 62+/-8%, severity 28+/-6%) and Th2 cytokine profiles (IL-4, IL-10) were comparable to those in wild-type controls.
Conclusions:
Hence, we show that immune responses mediated by STAT4, but not STAT6, contribute to the development of cardiac allograft vasculopathy. We speculate that when present, STAT4-mediated signaling pathways may promote cardiac allograft vasculopathy by directing Th1-specific lymphocyte recruitment, activation, and effector functions.
Insights
Signal transducer and activator of transcription (STAT)4 deficiency reduces cardiac allograft vasculopathy by limiting Th1 immune responses. STAT6 deficiency did not impact vasculopathy development in this transplant model.
Area of Science:
- Immunology
- Transplantation Biology
- Molecular Biology
Background:
- Cardiac allograft vasculopathy (CAV) is a major cause of graft failure.
- Transcription factor signaling pathways play a critical role in mediating immune responses in transplantation.
- Signal transducer and activator of transcription (STAT) proteins are key mediators of cytokine signaling.
Purpose of the Study:
- To investigate the role of STAT4 and STAT6 in mediating immune responses that lead to cardiac allograft vasculopathy.
- To elucidate the specific transcription factor signaling pathways involved in chronic rejection after cardiac transplantation.
Main Methods:
- Utilized a mouse cardiac transplant model with targeted gene deletion of STAT4 and STAT6 in recipient mice.
- Assessed the frequency and severity of vascular occlusion in cardiac grafts at day 55 post-transplantation.
- Quantified intragraft expression of Th1 and Th2 cytokines, and infiltrating immune cells using RT-PCR and immunohistochemistry.
Main Results:
- STAT4 deficiency significantly reduced the frequency and severity of cardiac allograft vasculopathy compared to wild-type controls.
- Reduced vasculopathy in STAT4-/- recipients was associated with decreased intragraft expression of interferon-gamma and IL-2.
- STAT4 deficiency led to fewer infiltrating mononuclear cells and reduced expression of selectin ligands, crucial for Th1 cell recruitment.
Conclusions:
- STAT4-mediated immune responses, but not STAT6, significantly contribute to the development of cardiac allograft vasculopathy.
- STAT4 signaling pathways promote CAV by directing Th1 lymphocyte recruitment, activation, and effector functions.
- Targeting STAT4 may offer a therapeutic strategy to prevent or mitigate chronic rejection in cardiac transplantation.
