Editing Podocyte (section)

{{Use dmy dates|date=September 2023}}
{{Short description|Type of kidney cell}}
{{Infobox cell
| Name        = Podocyte
| Latin       = podocytus
| Precursor   = [[Intermediate mesoderm]]
| Image       = Renal corpuscle-en.svg
| Caption     = The podocytes shown in green, line [[Bowman's capsule]] in the [[renal corpuscle]] and wrap around the [[Glomerular capillaries|capillaries]] as a major part of the [[Ultrafiltration (kidney)|filtration process]] in the [[kidney]]s
| System     =
| Location = [[Bowman's capsule]] of the [[kidney]]
}}
'''Podocytes''' are [[cell (biology)|cells]] in [[Bowman's capsule]] in the [[kidney]]s that wrap around [[capillary|capillaries]] of the [[glomerulus (kidney)|glomerulus]]. Podocytes make  up the epithelial lining of Bowman's capsule, the third layer through which [[Ultrafiltration (kidney)|filtration]] of blood takes place.<ref>{{DorlandsDict|six/000084389|Podocyte}}</ref> Bowman's capsule filters the [[blood]], retaining large [[molecule]]s such as [[protein]]s while smaller molecules such as [[water]], [[salt (chemistry)|salts]], and [[sugar]]s are filtered as the first step in the formation of [[urine]]. Although various [[organ (anatomy)|viscera]] have [[epithelium|epithelial]] layers, the name '''visceral epithelial cells''' usually refers specifically to podocytes, which are specialized epithelial cells that reside in the visceral layer of the capsule.

{{Anchor|Pedicel}} The podocytes have long primary processes called ''trabeculae'' that form secondary processes known as ''pedicels'' or foot processes (for which the cells are named ''[[wikt:podo-#Prefix|podo-]]'' + ''[[wikt:-cyte#Suffix|-cyte]]'').<ref name="Ovalle">{{cite book | vauthors = Ovalle WK, Nahirney PC |title=Netter's Essential Histology E-Book |url=https://books.google.com/books?id=mhy0BQAAQBAJ&q=podocyte+trabeculae&pg=PT380 |publisher=Elsevier Health Sciences |access-date=2 June 2020 |language=en |date=28 February 2013 |isbn= 978-1-4557-0307-4 }}</ref> The pedicels wrap around the capillaries and leave slits between them. Blood is filtered through these slits, each known as a '''filtration slit''', '''slit diaphragm''', or '''slit pore'''.<ref name="lote">{{cite book | vauthors = Lote CJ | chapter = Glomerular Filtration |title= Principles of Renal Physiology | date = 2012 | edition = 5th |page=34 | isbn = 978-1-4614-3784-0 | doi = 10.1007/978-1-4614-3785-7_3 | publisher = Springer Science+Business Media | location = New York }}</ref> Several proteins are required for the pedicels to wrap around the capillaries and function. When infants are born with certain defects in these proteins, such as [[nephrin]] and [[CD2AP]], their kidneys cannot function. People have variations in these proteins, and some variations may [[genetic predisposition|predispose]] them to [[kidney failure]] later in life. [[Nephrin]] is a [[Leucine zipper|zipper-like protein]] that forms the slit diaphragm, with spaces between the teeth of the zipper big enough to allow sugar and water through but too small to allow proteins through. Nephrin defects are responsible for congenital kidney failure. CD2AP regulates the podocyte cytoskeleton and stabilizes the slit diaphragm.<ref>{{cite journal | vauthors = Wickelgren I | title = First components found for new kidney filter | journal = Science | volume = 286 | issue = 5438 | pages = 225–226 | date = October 1999 | pmid = 10577188 | doi = 10.1126/science.286.5438.225 | s2cid = 43237744 }}</ref><ref>{{cite journal | vauthors = Löwik MM, Groenen PJ, Levtchenko EN, Monnens LA, van den Heuvel LP | title = Molecular genetic analysis of podocyte genes in focal segmental glomerulosclerosis--a review | journal = European Journal of Pediatrics | volume = 168 | issue = 11 | pages = 1291–1304 | date = November 2009 | pmid = 19562370 | pmc = 2745545 | doi = 10.1007/s00431-009-1017-x }}</ref>