TY - JOUR
T1 - Imaging of podocyte foot processes by fluorescence microscopy
AU - Grgic, Ivica
AU - Brooks, Craig R.
AU - Hofmeister, Andreas F.
AU - Bijol, Vanesa
AU - Bonventre, Joseph V.
AU - Humphreys, Benjamin D.
PY - 2012/5
Y1 - 2012/5
N2 - Visualizing podocyte foot processes requires electron microscopy, a technique that depends on special equipment, requires immunogold for colabeling, and does not take advantage of the growing number of in vivo fluorophores available. To address these limitations, we developed a genetic strategy to allow detailed visualization of single podocytes and their foot processes by conventional fluorescence microscopy. We generated a transgenic mouse line expressing a GFP-Cre-ERT2 fusion protein under the control of the collagen α1(I) promoter with strong podocyte expression. Administration of submaximal tamoxifen allowed genetic labeling of single podocytes when crossed with a Cre-reporter line. Of three different reporter systems that we evaluated for the ability to reveal fine structural details of podocytes, bigenic Coll1α1GCE;Gt(ROSA)26Sortm9(CAG-tdTomato)mice allowed podocyte labelingwith a strong and homogeneous reporter signal thatwas easily observed by epifluorescence. We could easily detect anatomic features of podocytes down to tertiary foot processes, and we were able to visualize and quantitate ultrastructural changes to foot processes after podocyte injury. In summary, using this method of genetic labeling and conventional fluorescence microscopy to visualize podocyte foot processes will complement electron microscopy and facilitate the analysis of podocytes and their precursors in vivo.
AB - Visualizing podocyte foot processes requires electron microscopy, a technique that depends on special equipment, requires immunogold for colabeling, and does not take advantage of the growing number of in vivo fluorophores available. To address these limitations, we developed a genetic strategy to allow detailed visualization of single podocytes and their foot processes by conventional fluorescence microscopy. We generated a transgenic mouse line expressing a GFP-Cre-ERT2 fusion protein under the control of the collagen α1(I) promoter with strong podocyte expression. Administration of submaximal tamoxifen allowed genetic labeling of single podocytes when crossed with a Cre-reporter line. Of three different reporter systems that we evaluated for the ability to reveal fine structural details of podocytes, bigenic Coll1α1GCE;Gt(ROSA)26Sortm9(CAG-tdTomato)mice allowed podocyte labelingwith a strong and homogeneous reporter signal thatwas easily observed by epifluorescence. We could easily detect anatomic features of podocytes down to tertiary foot processes, and we were able to visualize and quantitate ultrastructural changes to foot processes after podocyte injury. In summary, using this method of genetic labeling and conventional fluorescence microscopy to visualize podocyte foot processes will complement electron microscopy and facilitate the analysis of podocytes and their precursors in vivo.
UR - http://www.scopus.com/inward/record.url?scp=84860606114&partnerID=8YFLogxK
U2 - 10.1681/ASN.2011100988
DO - 10.1681/ASN.2011100988
M3 - Article
C2 - 22362911
AN - SCOPUS:84860606114
SN - 1046-6673
VL - 23
SP - 785
EP - 791
JO - Journal of the American Society of Nephrology
JF - Journal of the American Society of Nephrology
IS - 5
ER -