Expression of Cyt-c-Mediated Mitochondrial Apoptosis-Related Proteins in Rat Renal Proximal Tubules during Development

Abstract

Background: Apoptosis regulates embryogenesis, organ metamorphosis and tissue homeostasis. Mitochondrial signaling is an apoptotic pathway, in which Cyt-c and Apaf-1 are transformed into an apoptosome, which activates procaspase-9 and triggers apoptosis. This study evaluated Cyt-c, Apaf-1 and caspase-9 expression during renal development. Methods: Kidneys from embryonic (E) 16-, 18-, and 20-day-old fetuses and postnatal (P) 1-, 3-, 5-, 7-, 14-, and 21-day-old pups were obtained. Immunohistochemical analysis, dual-labeled immunofluorescence, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) technique assay and Western blot were performed in addition to histological analysis. Results: Immunohistochemistry showed that Cyt-c was strongly expressed in proximal and distal tubules (DTs) at all time points. Caspase-9 and Apaf-1 were strongly expressed in proximal tubules (PTs) but only weakly expressed in DTs. Dual-labeled immunofluorescence showed that most tubules expressed both Cyt-c and Apaf-1, except for some tubules that only expressed Cyt-c. The TUNEL assay showed a greater percentage of apoptotic cells in PTs compared to DTs. Apaf-1 and cleaved caspase-9 protein expression gradually increased during the embryonic period and peaked during the early postnatal period but apparently declined from P7. Cyt-c protein expression was weak during the embryonic period but obviously increased after P1. Conclusion: This study showed that PTs are more sensitive to apoptosis than DTs during rat renal development, even though both tubule segments contain a large number of mitochondria. Furthermore, Cyt-c-mediated mitochondrial apoptosis-related proteins play an important role in PTs during the early postnatal kidney development.

Neuroprotective Effect of Danhong Injection on Cerebral Ischemia-Reperfusion Injury in Rats by Activation of the PI3K-Akt Pathway

“…Cyt-C is a water-soluble protein encoded by a nuclear gene located outside the mitochondrial body. Cyt-C functions as an electron carrier in the mitochondrial respiratory chain, which plays an important role in the mitochondrial energy metabolism (Song et al, 2017). During apoptosis, Cyt-C is released into the cytoplasm, where it binds to apoptosis activation factor 1 (Apaf-1), and spontaneously activates caspase-9 to form a Cyt-C/Apaf-1/caspase-9 complex (Jiang et al, 2017).…”

Ozone alleviates ischemia/reperfusion injury by inhibiting mitochondrion‐mediated apoptosis pathway in SH‐SY5Y cells

“…It has been proved to play an important role in apoptotic process. Normally, cyt‐c is restricted within the mitochondria in healthy cells, but it will be released into cytoplasm to activate apoptotic pathway upon apoptotic process (Pal et al, 2016; Song et al, 2017). We proved that ozone reduced the mitochondrial damage of SH‐SY5Y cells caused by I/R injury and inhibited the release of cyt‐c from mitochondrion to cytoplasm.…”

Gypenoside Inhibits Endothelial Cell Apoptosis in Atherosclerosis by Modulating Mitochondria through PI3K/Akt/Bad Pathway

“…Cyt-c is a primary component of mitochondrial respiratory chain [38]. Cyt-c, released from mitochondria, could cause breaks in the electron transport chain, production of oxygen free radicals, and decreased ATP production, eventually leading to apoptosis [39,40].…”