Pyroptosis is the process of inflammatory cell death. The primary function of pyroptosis is to induce strong inflammatory responses that defend the host against microbe infection. Excessive pyroptosis, however, leads to several inflammatory diseases, including sepsis and autoimmune disorders. Pyroptosis can be canonical or noncanonical. Upon microbe infection, the canonical pathway responds to pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), while the noncanonical pathway responds to intracellular lipopolysaccharides (LPS) of Gram-negative bacteria. The last step of pyroptosis requires the cleavage of gasdermin D (GsdmD) at D275 (numbering after human GSDMD) into N- and C-termini by caspase 1 in the canonical pathway and caspase 4/5/11 (caspase 4/5 in humans, caspase 11 in mice) in the noncanonical pathway. Upon cleavage, the N-terminus of GsdmD (GsdmD-N) forms a transmembrane pore that releases cytokines such as IL-1β and IL-18 and disturbs the regulation of ions and water, eventually resulting in strong inflammation and cell death. Since GsdmD is the effector of pyroptosis, promising inhibitors of GsdmD have been developed for inflammatory diseases. This review will focus on the roles of GsdmD during pyroptosis and in diseases.

Beclin 1, the mammalian homologue of the yeast Atg6, is a key autophagy-promoting gene that plays a critical role in the regulation of cell death and survival of various types of cells. However, re...

Duchenne muscular dystrophy (DMD) is a degenerative muscle disease caused by genetic mutations that lead to the disruption of dystrophin in muscle fibers. There is no curative treatment for this devastating disease. Clustered regularly interspaced short palindromic repeat/Cas9 (CRISPR/Cas9) has emerged as a powerful tool for genetic manipulation and potential therapy. Here we demonstrate that CRIPSR-mediated genome editing efficiently excised a 23-kb genomic region on the X-chromosome covering the mutant exon 23 in a mouse model of DMD, and restored dystrophin expression and the dystrophin-glycoprotein complex at the sarcolemma of skeletal muscles in live mdx mice. Electroporation-mediated transfection of the Cas9/gRNA constructs in the skeletal muscles of mdx mice normalized the calcium sparks in response to osmotic shock. Adenovirus-mediated transduction of Cas9/gRNA greatly reduced the Evans blue dye uptake of skeletal muscles at rest and after downhill treadmill running. This study provides proof evidence for permanent gene correction in DMD.

Mitsugumin 53 (MG53), a muscle-specific TRIM family protein, is an essential component of the cell membrane repair machinery. Here, we examined the translational value of targeting MG53 function in tissue repair and regenerative medicine. Although native MG53 protein is principally restricted to skeletal and cardiac muscle tissues, beneficial effects that protect against cellular injuries are present in nonmuscle cells with overexpression of MG53. In addition to the intracellular action of MG53, injury to the cell membrane exposes a signal that can be detected by MG53, allowing recombinant MG53 protein to repair membrane damage when provided in the extracellular space. Recombinant human MG53 (rhMG53) protein purified from Escherichia coli fermentation provided dose-dependent protection against chemical, mechanical, or ultraviolet-induced damage to both muscle and nonmuscle cells. Injection of rhMG53 through multiple routes decreased muscle pathology in the mdx dystrophic mouse model. Our data support the concept of targeted cell membrane repair in regenerative medicine, and present MG53 protein as an attractive biological reagent for restoration of membrane repair defects in human diseases.

Irisin protects against ischemia/reperfusion injury to the lung by improving mitochondrial function.