apical-resection-mouse-model-to-study-early-mammalian-heart

Apical Resection Mouse Model to Study Early Mammalian Heart Regeneration

Cardiovascular disease plagues the whole world due to intensive lifestyle changes. Heart regeneration holds great promise for repairing and restoring ...

National Institutes of Health

Macroautophagy is an evolutionarily conserved intracellular degradation system used by life ranging from yeasts to mammals. The core autophagic machinery is composed of ATG (autophagy-related) protein constituents. One particular member of the ATG protein family, Atg7, has been the focus of recent research. Atg7 acts as an E1-like activating enzyme facilitating both microtubule-associated protein light chain 3 (LC3)-phosphatidylethanolamine and ATG12 conjugation. Thus, Atg7 stands at the hub of these two ubiquitin-like systems involving LC3 and Atg12 in autophagic vesicle expansion. In this review, I focus on the pleiotropic function of Atg7 in development, maintenance of health, and alternations of such control in disease.

Atg7 in development and disease: panacea or Pandora's Box?

The spalt (sal) family is a class of evolutionarily conserved genes originally identified in Drosophila as homeotic genes required for embryonic development. In vertebrates, the expression of sal-like 4 (SALL4) is specifically enriched in both embryonic and adult stem/stem-like cells. SALL4 is a master regulator that contributes to cell stemness in biological development and tumor growth. Thus, Sall4 has emerged as a target for gene therapy. In addition, numerous mutations affecting the Sall4 gene have been discovered and clinically linked to a series of congenital abnormalities, such as Duane/Duane-related syndromes, ventricular septal defect and premature ovarian failure. This review delineates the underlying mechanisms of key functions of SALL4 and its use as a target for gene therapy. Finally, I summarize and discuss advances made on the application of Sall4 and its functions in diagnostics and treatments for human diseases.

SALL4: engine of cell stemness.

Mouse embryonic stem cells (ESCs) are genetically more stable than somatic cells, thereby preventing the passage of genomic abnormalities to their derivatives including germ cells. The underlying mechanisms, however, remain largely unclear. In this paper, we show that the stemness factor Sall4 is required for activating the critical Ataxia Telangiectasia Mutated (ATM)-dependent cellular responses to DNA double-stranded breaks (DSBs) in mouse ESCs and confer their resistance to DSB-induced cytotoxicity. Sall4 is rapidly mobilized to the sites of DSBs after DNA damage. Furthermore, Sall4 interacts with Rad50 and stabilizes the Mre11-Rad50-Nbs1 complex for the efficient recruitment and activation of ATM. Sall4 also interacts with Baf60a, a member of the SWI/SNF (switch/sucrose nonfermentable) ATP-dependent chromatin-remodeling complex, which is responsible for recruiting Sall4 to the site of DNA DSB damage. Our findings provide novel mechanisms to coordinate stemness of ESCs with DNA damage response, ensuring genomic stability during the expansion of ESCs.

Jianhua Xiong

Center for Molecular Medicine,
National Heart,
Lung,
and Blood Institute,
Center for Molecular Medicine, National Heart, Lung, and Blood Institute

National Institutes of Health

Apical Resection Mouse Model to Study Early Mammalian Heart Regeneration

Jianhua Xiong

Center for Molecular Medicine,National Heart,Lung,and Blood Institute,Center for Molecular Medicine, National Heart, Lung, and Blood Institute

National Institutes of Health

Apical Resection Mouse Model to Study Early Mammalian Heart Regeneration

Center for Molecular Medicine,
National Heart,
Lung,
and Blood Institute,
Center for Molecular Medicine, National Heart, Lung, and Blood Institute