ESPN 50th Annual Meeting

ESPN 2017


 
Expression of connexins Cx 43 and Cx45 in developing human kidneys, postnatal healthy kidneys and in congenital nephrotic syndrome of the Finnish type (CNF)
NATALIJA FILIPOVIC 1 KATARINA VUKOJEVIC 2 IVANA BOCINA 3 MARIJAN SARAGA 4 MIRNA SARAGA-BABIC 1

1- DEPARTMENT OF ANATOMY, HISTOLOGY AND EMBRYOLOGY, SCHOOL OF MEDICINE, UNIVERSITY OF SPLIT, SPLIT, CROATIA
2- DEPARTMENT OF HISTOLOGY AND EMBRYOLOGY, SCHOOL OF MEDICINE, UNIVERSITY OF MOSTAR, BOSNIA AND HERZEGOVINA
3- DEPARTMENT OF BIOLOGY, UNIVERSITY OF SPLIT, SPLIT, CROATIA
4- DEPARTMENT OF PAEDIATRICS, UNIVERSITY HOSPITAL IN SPLIT, SPLIT, CROATIA
 
Introduction:

Connexins are transmembrane proteins that either form gap junctions, enabling cell-to cell communications, or form unpaired channels that allow communication between the cell and extracellular environment. In animals, Cx43 and Cx45 are found in renal vasculature, while Cx45 in vascular muscle wall and in glomeruli, including mesangial cells and podocytes. Cx43 expression decreases during epithelial – to mesenchymal transition, while increases in chronic renal diseases. Here, we investigate changes in expression and distribution of Cx43 and Cx45 during human nephrogenesis, in healthy and nephrotic kidneys.

Material and methods:

Human kidney tissue was dissected from conceptuses 8th to 38th postovulatory weeks old, from postnatal healthy kidneys as well as from the CNF kidneys.  Double immunofluorescence technique was used to detect expression and localization of Cx43 and Cx45, combined with DAPI nuclear stain. Their distribution and intensity of expression was presented semi-quantitatively.

Results:

In the metanephric cup stage moderate expression of Cx45 characterized all cup cells; weak Cx43 expression characterized mesenchymal cells corresponding to developing vasculature. During progression of development, Cx45 expression increased in all glomerular cells (visceral and parietal podocytes and mesangial cells), while Cx43 expression was restricted to vascular (endothelial) cells and parietal podocytes. Postnatally, Cx45 was observed throughout glomeruli; Cx43 was observed in vascular cells and parietal podocytes. Stronger and changed expression of Cx45 and Cx43 characterizes CNF glomeruli. Co-expression of Cx43/Cx45 was observed in some glomerular cells and parietal podocytes.

Conclusions:

During human kidney development Cx43 predominantly appears in the endothelium of blood vessels indicating its role in vasculogenesis. Cx45 is expressed during the whole nephrogenesis, pointing to importance of cell-to-cell communication in differentiation of podocytes and mesangial cells. Changed expression of Cx45/Cx43 in CNF kidneys imply interference of defective cells signaling with chronic kidney disease