in-vitro-assessment-cardiac-reprogramming-measuring-cardiac-specific

In vitro Assessment of Cardiac Reprogramming by Measuring Cardiac Specific Calcium Flux with a GCaMP3 Reporter

Cardiac reprogramming has become a potentially promising therapy to repair a damaged heart. By introducing multiple transcription factors, including ...

a-modified-murine-heterotopic-heart-transplant-protocol-matching

A Modified Murine Heterotopic Heart Transplant Protocol Matching Contemporary Standards of Aseptic Technique, Anesthesia, and Analgesia

The development of experimental models of cardiac transplantation in animals has contributed to many advances in the fields of immunology and solid organ ...

The University of Michigan, Ann Arbor

The University of Western Australia

Reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a potentially promising strategy for regenerating a damaged heart. However, low fibroblast-cardiomyocyte conversion rates remain a major challenge in this reprogramming. To this end, here we conducted a chemical screen and identified four agents, insulin-like growth factor-1, Mll1 inhibitor MM589, transforming growth factor-β inhibitor A83-01, and Bmi1 inhibitor PTC-209, termed IMAP, which coordinately enhanced reprogramming efficiency. Using α-muscle heavy chain-GFP-tagged mouse embryo fibroblasts as a starting cell type, we observed that the IMAP treatment increases iCM formation 6-fold. IMAP stimulated higher cardiac troponin T and α-actinin expression and increased sarcomere formation, coinciding with up-regulated expression of many cardiac genes and down-regulated fibroblast gene expression. Furthermore, IMAP promoted higher spontaneous beating and calcium transient activities of iCMs derived from neonatal cardiac fibroblasts. Intriguingly, we also observed that the IMAP treatment repressed many genes involved in immune responses, particularly those in specific C-C chemokine signaling pathways. We therefore investigated the roles of C-C motif chemokine ligand 3 (CCL3), CCL6, and CCL17 in cardiac reprogramming and observed that they inhibited iCM formation, whereas inhibitors of C-C motif chemokine receptor 1 (CCR1), CCR4, and CCR5 had the opposite effect. These results indicated that the IMAP treatment directly suppresses specific C-C chemokine signaling pathways and thereby enhances cardiac reprogramming. In conclusion, a combination of four chemicals, named here IMAP, suppresses specific C-C chemokine signaling pathways and facilitates Mef2c/Gata4/Tbx5 (MGT)-induced cardiac reprogramming, providing a potential means for iCM formation in clinical applications.

Liu Liu

Department of Cardiac Surgery,
Cardiovascular Center,
Department of Cardiac Surgery, Cardiovascular Center

The University of Michigan, Ann Arbor

In vitro Assessment of Cardiac Reprogramming by Measuring Cardiac Specific Calcium Flux with a GCaMP3 Reporter

A Modified Murine Heterotopic Heart Transplant Protocol Matching Contemporary Standards of Aseptic Technique, Anesthesia, and Analgesia

Liu Liu

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Cardiac Surgery,Cardiovascular Center,Department of Cardiac Surgery, Cardiovascular Center

The University of Michigan, Ann Arbor

In vitro Assessment of Cardiac Reprogramming by Measuring Cardiac Specific Calcium Flux with a GCaMP3 Reporter

A Modified Murine Heterotopic Heart Transplant Protocol Matching Contemporary Standards of Aseptic Technique, Anesthesia, and Analgesia

Department of Cardiac Surgery,
Cardiovascular Center,
Department of Cardiac Surgery, Cardiovascular Center