Expression Of P-CaMKâ…¡ In The Pre-b(?)tzinger Complex Of Rats And Expression Of LC3B And BECLIN1in The Primary Biliarye Cirrhosis Of The Liver

In this study, we used immunohistochemistry, immunofluorescence and immune-electron microscopy to observe expression of phospho-Ca2+/calmodulin-dependentprotein kinase II (P-CaMKII) in the pre-B tzinger complex of rats and expression ofautophagy-related protein LC3B and BECLIN1in primary biliary cirrhosis of liver tissue.We aimed to explore the significance of these proteins in their respective parts of theexpression.The pre-B tzinger complex (pre-B tC) in the ventrolateral medulla oblongata is apresumed kernel of respiratory rhythmogenesis. Ca2+-activated non-selective cationiccurrent is an essential cellular mechanism for shaping inspiratory drive potentials. Ca2+/calmodulin-dependent protein kinase II (CaMKII), an ideal ’interpreter’ of diverse Ca2+signals, is highly expressed in neurons in mediating various physiological processes. Yet,less is known about CaMKII activity in the pre-B tC. Using neurokinin-1receptor as a marker of the pre-B tC, we examined phospho-CaMKII subcellular distribution, andfound that P-CaMKII was extensively expressed in the region. P-CaMKII-ir neurons wereusually oval, fusiform, or pyramidal in shape. Counts of double-labeled neurons wereprocessed in60sections of six brainstems. Among966NK1R-ir neurons,63.7%(615/966)were double-labeled with P-CaMKII in the pre-B tC. Among the double-labeled neurons,19.3%(119/615) were small fusiform. P-CaMKII-ir neurons larger than300μm2weredevoid of NK1R immunoreactivity. P-CaMKII immunoreactivity was distributed withinsomas and dendrites, and specifically in association with the post-synaptic density. Insomas, of21synapses detected with P-CaMKII immunoreactivity,8(38.1%) were of thesymmetric type.The rest were of the asymmetric type. However, in dendrites, they weremostly localized to asymmetric synapses.87synapses that were P-CaMKIIimmunoreactivity,81(93.1%) were of the asymmetric type. Only a few were of thesymmetric type. The distribution of P-CaMKII at synapses, perisynaptic, andextrasynaptic regions indicates distinct functional significance of CaMKII in the pre-B tC.P-CaMKII asymmetric synaptic identification implicates that CaMKII may sense andmonitor Ca2+activity, and phosphorylate post-synaptic proteins to modulate excitatorysynaptic transmission, which may contribute to respiratory modulation and plasticity. Insomas, CaMKII acts on both symmetric and asymmetric synapses, mediating excitatoryand inhibitory synaptic transmission. P-CaMKII was also localized to the perisynaptic andextrasynaptic regions in the pre-B tC.Primary biliary cirrhosis (PBC) is an autoimmune liver disease, which isserologically characterised by antimitochondrial antibodies (AMAs) and histologically acholangitis of small bile ducts (chronic non-suppurative destructive cholangitis). Clinically,PBC presents with chronic, progressive cholestasis and liver failure. Sasaki M foundautophagy may have a possible role in the pathogenesis of bile duct lesions in PBC. Theabove observation is only found in biliary epithelial cells, while autophagy has not beenreported in liver cells. We observed obvious autophagosome in liver cells of patients with PBC, so the role of autophagy on PBC liver cell injury deserves further investigation. ThePBC cases were collected and relevant indicators were analyzed. Then,immunohistochemistry, immunofluorescence and electron microscopy were performed toinvestigate the distribution of autophagosome in hepatocytes and biliary epithelial cells inthe collected cases. The results showed that in the50cases with PBC, ALP and γ-GGTwere significantly increased. Autophagy-related proteins LC3B and BECLIN1were bothexpressed in the hepatocytes and biliary epithelial cells cytoplasm of the selected AMAantibody-positive patients with PBC, and most expressed hepatocytes are close to theportal area. Furthermore, LC3B and BECLIN1were coexisted in some liver cells.Autophagosome was observed in hepatocytes and biliary epithelial cells undertransmission electron microscopy, accompanied by these cells injured. These resultssuggest that autophagy may be involved in hepatocytes and biliary epithelial cells injury inPBC patients, providing morphological evidences for the role of autophagy on thehepatocytes and biliary epithelial cells injury.