Fig. 3

CCRR alleviates destruction of intercalated discs and gap junction in HF mice. a Typical examples of electron microscopic images (30,000× magnification) showing the deranged intercalated discs in HF mice (left panels) and patients (right panels), and the effects of CCRR overexpression by Lv-CCRR on the microstructure of left ventricular cardiac muscles in HF mice. Marked disruption of intercalated discs and gap junction was consistently observed in HF myocardium (indicated by arrows), and such derangement was ameliorated and restored to normal conditions after pretreatment with Lv-CCRR, but not with Lv-NC. Similar observations were repeated in another three HF mice. b Effects of CCRR overexpression by Lv-CCRR on the protein levels of connexin43 (Cx43) and CIP85 (the Cx43-interacting protein that regulates the endocytic trafficking of Cx43 for degradation) in HF mice. Upper panel: examples of Western blot bands; lower panel: averaged data on Cx43 and CIP85 protein levels. Comparisons of Cx43 and CIP85 at the protein levels were made between the membrane and cytoplasm fractions. Cx43 level was markedly decreased in the membrane, but increased in the cytoplasm, which resulted in an overall reduction of total protein level, indicating the enhanced endocytic trafficking of Cx43 in HF mice compared to the Sham-operated control animals. The membrane bands were normalized to N-cadherin (N-Cad), and the cytosolic and total protein bands were normalized to GAPDH (GAP). ^*P < 0.05, ^**P < 0.01, ^***P < 0.001; ^#P < 0.05, ^##P < 0.01, ^###P < 0.001 Lv-CCRR vs. HF; n = 5 heart samples of membrane fraction for each group, n = 6 for cytoplasmic fraction, and n = 6 for total protein. Similar changes were observed with CIP85, but its total protein level remained unaffected. ^*P < 0.05, ^**P < 0.01; ^##P < 0.01, Lv-CCRR vs. HF; n = 5 heart samples of membrane fraction for each group, n = 6 for cytoplasmic fraction, and n = 6 for total protein