Connexin 43 Knockdown Induces Mitochondrial Dysfunction and Affects Early Developmental Competence in Porcine Embryos

Abstract

Connexin 43 (CX43) is a component of gap junctions. The lack of functional CX43 induces oxidative stress, autophagy, and apoptosis in somatic cells. However, the role of CX43 in the early development of porcine embryos is still unknown. Thus, the aim of this study was to investigate the role of CX43, and its underlying molecular mechanisms, on the developmental competence of early porcine embryos. We performed CX43 knockdown by microinjecting dsRNA into parthenogenetically activated porcine parthenotes. The blastocyst development rate and the total number of cells in the blastocysts were significantly reduced by CX43 knockdown. Results from FITC-dextran assays showed that CX43 knockdown significantly increased membrane permeability. ZO-1 protein was obliterated in CX43 knockdown blastocysts. Mitochondrial membrane potential and ATP production were significantly reduced following CX43 knockdown. Reactive oxygen species (ROS) levels were significantly increased in the CX43 knockdown group compared to those in control embryos. Moreover, CX43 knockdown induced autophagy and apoptosis. Our findings indicate that CX43 is essential for the development and preimplantation of porcine embryos and maintains mitochondrial function, cell junction structure, and cell homeostasis by regulating membrane permeability, ROS generation, autophagy, and apoptosis in early embryos.

The relationship of 4‐vinylcyclohexene diepoxide toxicity with cell death, oxidative stress, and gap junctions in female rat ovaries

“… 20 In many different tissue types, the decrease in Cx43 and the increase in ROS formation induced cell death. 21 In this study, with increased Casp3 expression, we showed that increased oxidative stress due to VCD exposure decreased Cx43 expression important for survival in granulosa cells and increases apoptosis in cells. Thus, thanks to this study, the relationship of VCD toxicity to Cx43 oxidative stress and apoptosis in damaged ovary was evaluated for the first time.…”

“…In the same study, the researchers reported that intercellular apoptotic signals were transmitted between each other through gap junctions; therefore, the gap junction protein expressions increased in apoptosis, but Cx43 regulated the survival of cells rather than the channel function through which death signals were transmitted 20. In many different tissue types, the decrease in Cx43 and the increase in ROS formation induced cell death 21. In this study, with increased Immunohistochemical staining of Casp3 in ovary tissue.…”

“… 20 In studies conducted on different tissue types and cells, it has been stated that with the decrease or inhibition of Cx43 expression, the amount of ROS increases in cells and as a result, apoptosis is induced. 21 …”

“…20 In studies conducted on different tissue types and cells, it has been stated that with the decrease or inhibition of Cx43 expression, the amount of ROS increases in cells and as a result, apoptosis is induced. 21 The purpose of this study was to demonstrate the relationship between the oxidative stress marker iNOS, the effector protein of apoptosis Casp3, and the gap junction protein Cx43 in rats exposed to VCD toxicity by histopathological, immunohistochemical, and RT-qPCR analyses.…”

Pannexins and Connexins: Their Relevance for Oocyte Developmental Competence

“…Connexin-43 knockdown in parthenogenetically activated porcine embryos was responsible for the reduction of the membrane permeability, mitochondrial membrane potential and ATP production, and for the enhanced level of reactive oxygen species. Additionally, blastocyst developmental rate, and the total cell number were decreased [ 85 ]. The importance of Cx43 for the oocyte quality was also confirmed in bovine.…”