Expression of protein kinase C isoenzymes α, β_I, and δ in subtypes of intercalated cells of mouse kidney

Abstract

Recent studies of the distribution of PKC isoenzymes in the mouse kidney demonstrated that PKC-α, -βI, and -δ are expressed in intercalated cells. The purpose of this study was to identify the intercalated cell subtypes that express the different PKC isoenzymes and determine the location of the PKC isoenzymes within these cells. Adult C57BL/6 mice kidney tissues were processed for multiple-labeling immunohistochemistry. Antibodies against the vacuolar H+-ATPase and pendrin were used to identify intercalated cell subtypes, whereas antibodies against calbindin D28K and aquaporin-2 (AQP2) were used to identify connecting tubule cells and principal cells of the collecting duct, respectively. Within type A intercalated cells, PKC-δ was highly expressed in the apical part of the cells, whereas immunoreactivity for both PKC-α and PKC-βI was weak. Type B intercalated cells exhibited strong expression of PKC-α, -βI, and -δ. PKC-α and -βI were localized throughout the cytoplasm, whereas PKC-δ was restricted to the basal domain. Within non-A-non-B cells, immunoreactivity for both PKC-α and PKC-βI was high in intensity and localized diffusely in the cytoplasm, whereas PKC-δ was localized in the apical part of the cells. None of the PKC isoenzymes (PKC-α, -βI, or -δ) were expressed in the calbindin D28K-positive connecting tubule cells. Within AQP2-positive principal cells of the collecting duct, PKC-α was expressed on the basolateral plasma membrane, but no significant staining was detected for PKC-βI and -δ. In summary, this study demonstrates distinct and differential expression patterns of PKC-α, -βI, and -δ in the three subtypes of intercalated cells in the mouse kidney.

ENaC activity is increased in isolated, split-open cortical collecting ducts from protein kinase Cα knockout mice

“…cipal cells) but is not detectable in knockout mice, confirming the previous work of Madsen and coworkers (22). ENaC P o is increased in PKCa knockout mice.…”

“…There are conflicting reports in the literature about which isoforms of PKC are present in principal cells of the mouse cortical collecting duct. One report suggested that, in mice, there was no PKC present in principal cells (29); subsequent work suggested that PKC␣ was present, but no other typical or novel isoforms (22). Therefore, we made use of PKC␣ knockout mice to examine PKC regulation of ENaC in isolated split-open collecting duct principal cells.…”

Angiotensin II Stimulates Vacuolar H+-ATPase Activity in Renal Acid-Secretory Intercalated Cells from the Outer Medullary Collecting Duct

“…[25][26][27] On the basis of the observation that intracellular Ca 2ϩ plays a critical role, we tested the involvement of ϩ -independent pH i recovery of OMCD IC. OMCD were preincubated for 10 min with AngII, and AngII was present in all Na ϩ -free solutions.…”

“…Immunohistochemistry demonstrated the expression of PKC-␣, PKC-␤1, PKC-, and PKC-␦ in IC of the collecting duct. 25,27 Evidence from freshly isolated OMCD IC as well as from cell culture models 19,31,54 suggests that PKC has a stimulatory effect on H ϩ -ATPase activity. In addition, our experiments indicate that intact ERK1/2 mitogen-activated protein kinases and PI3-K are required for the stimulation to occur.…”

Mitochondrial TCA cycle intermediates regulate body fluid and acid-base balance

“…OXGR1 is a Gq-coupled GPCR (7), suggesting the involvement of Ca 2+ and PKC in the adjacent intercalated cells. Interestingly, various isoenzymes of PKC (e.g., PKC-α, PKC-β1), which control tubular ion and water transport but also signal the actions of hormones and growth factors on cell proliferation and differentiation, show distinct high level expression in type B and non-A-non-B intercalated cells (15). Whether OXGR1 signaling involves any of these PKC isoenzymes and what other intercalated cell functions OXGR1 may control need to be further investigated.…”