OBJECTIVETo investigate the expression and function of PKD1 and PKD2 in different kidney tissues and cell lines.

METHODSImmunoprecipitation, Western blotting, In situ hybridization and immunohistochemical staining methods were used to observe the expression of PKD1 mRNA and PKD2 mRNA and their protein abundance in different kidney tissues and cell lines.

RESULTSCoordinate expressions of PKD1 and PKD2 were found in all kidney tissues and cell lines. Distribution of PKD1 mRNA and PKD2 mRNA and their protein polycystin-1 and polycystin-2 in normal human adult kidney tissue were mainly expressed in the medullary collecting ducts and distal tubules. Positive staining was also found in the majority of cyst-lining epithelial cells of PKD1 cystic kidney tissue, PKD1 cyst-lining epithelia cell line and LLC-PK1. The expression level of them in cystic epithelia of ADPKD kidney tissue was much higher than that in adult renal tubules (P < 0.01).

CONCLUSIONSSimilar expression pattern of PKD1 and PKD2 and their different tissue distribution in different kidney tissues show that the molecular mutuality of PC-1 and PC-2 might be the base of their functional correlation. Polycystins might play an important role in the maintenance of tubular architecture.

Adult ; Animals ; Cell Line ; Gene Expression ; Humans ; Kidney ; metabolism ; Kidney Tubules, Collecting ; metabolism ; Kidney Tubules, Distal ; metabolism ; Kidney Tubules, Proximal ; cytology ; Polycystic Kidney, Autosomal Dominant ; pathology ; RNA, Messenger ; biosynthesis ; genetics ; Swine ; TRPP Cation Channels ; metabolism

Laminin, an extracellular matrix glycoprotein composed of three polypeptide chains such as alpha , beta, and gamma is distributed in basement membranes of epithelium, muscle, and nervous tissues. Laminin functions as an extracellular cytoskeleton and regulates the differentiation and polarization of cells adjacent to the basement membrane. Along with type IV collagen and heparan sulfate proteoglycan, laminin forms a spike -like structure in the renal glomerular basement membrane (GBM). It has been previously demonstrated that the distribution and immune reaction of laminin are changed in response to the conditions of glomerulonephritis and that laminin plays a role in the reformation of GBM as well as the regeneration of renal glomerular cells. In the present study, the profile of expression and distribution of laminin/laminin beta1 chain were examined in different developmental stages and upon adriamycin administration. Kidney obtained from fetuses (16, 18, and 20 days old) and infants (1 and 7 days old) of Sprague -Dawley rats were either cryosectioned for immunohistochemical assays or ultrathin -sectioned for electron microscopy using immunogold staining methods. The results were as follows: 1. Intensive expression of laminin was observed in the GBM and surrounding mesenchymal tissues obtained from 16, 18, and 20 days old fetuses and in the glomerulus from one day neonates, whereas the level of staining decreased in the glomerulus from 7 days old infants. 2. Immunogold particles were observed in the comma -shaped nephron, in particular in cisternae of rough endoplasmic reticulum, vesicles and nuclear membrane of endothelial cells and mesangial cells obtained from 18 days old fetuses. 3. The immune reactions of laminin beta1 chain were trace detected in the kidney from fetuses (16, 18, and 20 days old) and weakly in tissues surrounding blood capillary and mesangial tissues from one day old neonates. 4. After 24 hours following adriamycin treatment, the reactivity of laminin was slightly enhanced in the renal glomerulus, when compared with that of untreated controls. This enhancement persisted up to 1 week of adriamycin treatment. Laminin beta1 chain was weakly detectable, while further treatment with adriamycin for another 24 hours reduced the intensity of laminin beta1 chain. Taken together, these results suggest that laminin is localized in the GBM at the high level during early fetal stages but the expression levels decrease after birth. Moreover, administration with adriamycin may result in an increase in the immune reactivities of laminin and laminin beta1 chain by renal tissue damage followed by renal regeneration.
Animals ; Basement Membrane ; Capillaries ; Collagen Type IV ; Cytoskeleton ; Doxorubicin ; Endoplasmic Reticulum, Rough ; Endothelial Cells ; Epithelium ; Extracellular Matrix ; Fetus ; Glomerular Basement Membrane ; Glomerulonephritis ; Glycoproteins ; Heparan Sulfate Proteoglycans ; Humans ; Infant ; Infant, Newborn ; Kidney* ; Laminin* ; Mesangial Cells ; Microscopy, Electron ; Nephrons ; Nuclear Envelope ; Parturition ; Rats* ; Regeneration

PURPOSE: It has been proposed that a decreased nephron number may be associated with the increased risk of glomerulosclerosis. In order to test the hypothesis that a reduced number and an increased volume of glomeruli may contribute to the pathogenesis of focal segmental glomerulosclerosis (FSGS), we compared the number and volume of glomeruli between 9 patients with FSGS and 8 with minimal change nephrotic syndrome (MCNS). METHODS: Mean glomerular volume was measured using the method of Weibel and Gomez. An estimate of glomerular number (index) was obtained by multiplying the cortical volume of a kidney by the fraction of renal cortex made up of glomeruli and dividing this by the mean glomerular volume for that kidney x 10(6). We determined kidney volume from ultrasonographic measurement. RESULTS: Patients with FSGS had significantly greater glomerular volume than patients with MCNS [2.02+/-0.36 (x10(6) micrometer3) vs. 1.57+/-0.27 (x10(6) micrometer3)] (p<0.025). However, there was no significant difference in the index of glomerular number (estimated glomerular number) between FSGS & MCNS patients (2.8+/-1.4 vs. 3.0+/-0.8). CONCLUSION: The glomerular volume was greater in FSGS patients than MCNS patients. But there was no significant difference in the index of glomerular number between patients with FSGS and MCNS.
Glomerulosclerosis, Focal Segmental* ; Humans ; Kidney ; Kidney Glomerulus ; Nephrons* ; Nephrosis, Lipoid* ; Nephrotic Syndrome

Occludin is a cell adhesion molecule that is abundantly expressed in the kidney. However, the expression pattern in various renal epithelial cells is not well established. The purpose of this study was to determine the cellular localization along the tubular epithelial cells in the kidney. Kidneys from adult pigs crossbred of Yorkshire, Landrace and Duroc (three breeds) were processed for immunohistochemistry. Thiazide sensitive sodium chloride cotransporter (TSC), Na+-KATPase bat1, calbindinD28k, and H+-ATPase were used to identify the thick ascending limb, distal convoluted tubule, connecting tubule, and collecting duct, respectively. In the pig kidney, occludin was expressed in the apical domain of the tubular epithelial cells. The immunoreactivity of occludin was strongest in the collecting duct, and then gradually decreased in the connecting tubule, distal convoluted tubule, and thick ascending limb. Occludin expression was weak in the thin limbs of the loop of henle and in the proximal tubule in the pig kidney. These results suggest that occludin may be a major adhesion molecule in distal tubular epithelial cells and play a critical role in maintaining epithelial polarity of these nephron segments.
Adult ; Cell Adhesion ; Epithelial Cells ; Extremities ; Humans ; Immunohistochemistry ; Kidney ; Loop of Henle ; Nephrons ; Occludin ; Sodium Chloride Symporters ; Swine

To depend body potassium balance during chronic hypokalemia, the kidney actively reabsorbs potassium. Previous work suggested that potassium reclamation occurred at the distal tubule and collecting duct. We used immunohistochemistry of normal and potassium-deprived(two weeks) rats to determine the intrarenal distribution and alteration of expression of Na/K-ATPase alpha1 and beta1 subunit protein and also whether the increased numbers of both subunits reside in the apical or basolateral membranes. In the normal rats, alpha1 and beta1 immunoreactivity was prominent in the medullary and cortical thick ascending limb, distal convoluted tubule, and connecting segment. Cortical collecting duct, glomerular epithelial cell, and intraglomerular mesangial cell exhibited moderate immunoreactivity, whereas proximal tubule and medullary collecting duct were weakly labeled in alpha1 subunit. In beta1 subunit, cortical collecting duct and proximal tubule exhibited moderate immunoreactivity, and medullary collecting duct was very weakly labeled. In the K-deprived rats, a pattern of cellular labeling of both subunits was identical to that of normal rats. Marked increases of immunoreactivity were evident in the inner stripe of the outer medullary collecting duct and proximal portion of the inner medullary collecting duct. In these segment, alpha1 and beta1 immunoreactivity was expressed at the basolateral pole, and no apical expression was detected. In contrast, immunoreactivity of the medullary and cortical thick ascending limb, distal convoluted tubule, connecting segment, and cortical collecting duct was decreased. These results suggest that Na/K-ATPase alpha1 and beta1 subunit are differentially expressed in different nephron segments and chronic hypokalemia must also upregulate K exit pathways in the basolateral membrane of inner stripe of the outer medullary collecting duct and proximal portion of the inner medullary collecting duct to promote recycling and limit secretion of K.
Animals ; Epithelial Cells ; Extremities ; Hypokalemia* ; Immunohistochemistry ; Kidney ; Membranes ; Mesangial Cells ; Nephrons ; Potassium ; Rats ; Recycling

E-cadherin is a cell adhesion molecule that is expressed abundantly in the kidney. However, the expression pattern in various renal epithelial cells is not well established. The purpose of this study was to determine the cellular localization along the nephron segments in the rat kidney. Kidneys from adult Sprague Dawley rats were fixed in 4% paraformaldehyde and processed for immunohistochemistry. Bumetanide-sensitive Na+/K+/2Cl- cotransporter (BSC1), thiazide-sensitive Na+/Cl- cotransporter (TSC), calbindin D28k, and H+-ATPase were used to identify the thick ascending, distal convoluted stubule, connecting tubule, and collecting duct, respectively. In the rat kidney, Ecadherin was expressed mainly in the basolateral domain of the collecting duct and papillary surface epithelial cells. The expression level of E-cadherin changed gradually in the connecting tubule and became moderate in the distal convoluted tubule, thick ascending limb, and loop of Henle. The S1 and S2 segment of the proximal tubule showed weak immunoreactivity. However, E-cadherin was not expressed in the S3 segment of the proximal tubule in the rat kidney. These results suggest that E-cadherin is a major adhesion molecule in the collecting duct and papillary surface epithelium, and that E-cadherin may play a critical role in maintaining the epithelial polarity of these nephron segments.
Adult ; Animals ; Cadherins ; Calcium-Binding Protein, Vitamin D-Dependent ; Cell Adhesion ; Epithelial Cells ; Epithelium ; Extremities ; Formaldehyde ; Humans ; Immunohistochemistry ; Kidney ; Loop of Henle ; Nephrons ; Polymers ; Rats ; Rats, Sprague-Dawley

Ammonia metabolism is a fundamental process in the maintenance of life in all living organisms. Recent studies have identified ammonia transporter family proteins in yeast (Mep), plants (Amt), and mammals (Rh glycoproteins). In mammalian kidneys, where ammonia metabolism and transport are critically important for the regulation of systemic acid - base homeostasis, basolateral Rh B glycoprotein and apical/basolateral Rh C glycoprotein are expressed along the distal nephron segments. Data from experimental animal models and knockout mice suggest that the Rh glycoproteins appear to mediate important roles in urinary ammonia excretion.
Ammonia ; Animals ; Glycoproteins ; Homeostasis ; Humans ; Kidney ; Kidney Tubules, Collecting ; Mammals ; Mice ; Mice, Knockout ; Models, Animal ; Nephrons ; Proteins ; Yeasts

OBJECTIVETo study the clinicopathologic features of membranous nephropathy coexisting with IgA nephropathy.

METHODSThe renal biopsies performed in Peking University First Hospital during the period from January, 1998 to April, 2006 were retrospectively reviewed. The clinicopathologic features of 11 cases of membranous nephropathy coexisting with IgA nephropathy were studied. Electron microscopy with immunogold labeling for IgG and IgA were also performed.

RESULTSThe mean age of patients was 39.9 years. The male-to-female ratio was 1:2.9. The patients mainly presented with proteinuria. Proteinuria of nephrotic level was seen in 7 cases (63.6%). Seven cases also had associated microscopic hematuria. None of them showed evidence of renal insufficiency. Cases with secondary diseases, such as hepatitis virus infection and systemic lupus erythematosus, were excluded from the study. Histologically, vacuolation and thickening of glomerular basement membrane was seen. There was also mild mesangial hypercellularity and increase in mesangial matrix. Occasional glomeruli with crescent formation were identified in 2 cases. Immunofluorescence study showed granular staining for IgG and C3 along glomerular capillary walls, in addition to clumps of IgA deposits in mesangium. Electron microscopy revealed subepithelial and mesangial electron-dense deposits. Immunogold labeling showed IgG and IgA localized in the subepithelial and mesangial deposits respectively.

CONCLUSIONMembranous nephropathy coexisting with IgA nephropathy possesses the clinicopathologic features of both components. It might be caused by independent occurrence of the two entities.

Adult ; Female ; Glomerular Basement Membrane ; immunology ; pathology ; ultrastructure ; Glomerular Mesangium ; immunology ; pathology ; ultrastructure ; Glomerulonephritis, IGA ; complications ; immunology ; pathology ; Glomerulonephritis, Membranous ; complications ; immunology ; pathology ; Humans ; Immunoglobulin A ; metabolism ; Immunoglobulin G ; metabolism ; Kidney Glomerulus ; immunology ; pathology ; ultrastructure ; Male ; Middle Aged ; Retrospective Studies

OBJECTIVETo study the clinicopathologic features of collagen III glomerulopathy and its cause, pathogenesis and prognosis.

METHODSFive cases of collagen III glomerulopathy that collected from 2005 to 2014 were observed by renal biopsy. The morphologic characteristics were studied by light microscopy, immunofluorescence, immunohistochemical and electron microscopy.

RESULTSThe glomerular mesangium became expansion but no hypercellularity, basement membrane appeared thickened. The glomeruli showed collagen type III deposit by immunohistochemistry method, and collagen fibers increased by electron microscopy. The patients often show serious proteinuria, nephrotic syndrome and renal function damage.

CONCLUSIONSCollagen III glomerulopathy is an idiopathic glomerular disease, characterized by massive accumulation of collagen type III within the glomerular mesangial areas and basement membrane. Collagen III glomerulopathy is extremely rare. The etiology and pathogenesis may relate to the abnormality of collagen III gene. There is no specific treatment for it and its prognosis is poor.

Basement Membrane ; metabolism ; Biopsy ; Collagen Type III ; genetics ; metabolism ; Female ; Fluorescent Antibody Technique ; Glomerular Mesangium ; metabolism ; Humans ; Immunohistochemistry ; Kidney Diseases ; etiology ; pathology ; Kidney Glomerulus ; pathology ; Microscopy, Electron ; Prognosis ; Proteinuria ; diagnosis

DISCUSSION Acute regulation of sodium pump activity There is a burgeoning literature on mechanisms responsible for short term regulation of Na,K-ATPase activity (Aperia et al, 1996, 1994; Boron et al, 1997; Bertorello & Katz, 1993). Pathways linked to both generation of protein kinase C (PKC) and/or cyclic-AMP dependent protein kinase A are postulated to regulate Na,K-ATPase activity by changing the alpha catalytic subunit phosphorylation status. However, phosphorylation has been associated with both decreased activity (Aperia et al, 1994; Chibalin et al, 1995; Middleton et al, 1993; Satoh et al, 1993a, 1993b), and increased activity (Carranza et al, 1996a, 1996b), and no change in activity (Boron et al, 1997). There is also evidence that PKC causes a withdrawal of sodiuln pumps from the basolateral membranes even if there is mutation of the phosphorylation site (Boron et al, 1997). Proximal tubule Na,K-ATPase activity is also inhibited (whether directly or indirectly is not known) by activation of phospholipase A2 which stimulates production of arachidonate metabolites of cytochrome P-450 such as 20-HETE (Aperia et al, 1996; Nowicki et al, 1997; Ominato et al, 1996). Although the precise signaling mechanisms re main to be elucidated for the responses to altered blood pressure, our results indicate that the inhibition of the sodium pump activity in PT is due to structural modification of the pump itself or an associated regulator, rather than solely mediated by trafficking of active pumps to a new location, because the data demonstrate. significant changes in total ATPase activity that persist through membrane fractionation and phase partitioning, and our results implicate a role of cat P45O aa metabolism to 20-HETE in the response(Zhang et al, 1998) Altered natriuretic responses in hypertension As discussed in the introduction, an altered natriuretic response to an elevation in blood pressure is the hallmark of hypertension. The Spontaneously Hypertensive Rat (SHR)has numerous renal defects that could account for the development of hypertension. In regards to this project, the PT of SHR fail to respond normally to the natriuretic hormone dopamine (Kinoshita et al, 1989), and they have enhanced tubuloglomerular feedback (TGF) response (reviewed in Cowley & Roman, 1997). Our results indicate a distribution of apical sodium transportes in SHR is the same as in acutely hypertensive SD (Magyar et al, 1997), In summary, our findings to date suggest that the dynamic regulation of proximal tubule and loop of Henle sodium transport by fluctuations in blood pressure may be mediated by changes in sodium transporter characteristics at both the apical and basolateral membranes: 1) by reversible inhibition of basolateral Na,K-ATPase activity in the PT and activation in the TALH, and 2) relocation of a set of apical proteins, including NHE-3 and NaPi, consistent with redistribution to intermicrovillar cleft region and/or internalization to endosomal pools in the PT. The reciprocal modulation of Na,K-ATPase activity in PT and TALH contributes the driving force for activating TGF, while minimizing changes in delivery of salt and water to the hormone sensitive distal nephron.
Adenosine Triphosphatases ; Animals ; Blood Pressure ; Boron ; Catalytic Domain ; Cats ; Cyclic AMP-Dependent Protein Kinases ; Cytochrome P-450 Enzyme System ; Dopamine ; Hypertension* ; Loop of Henle ; Membranes ; Metabolism ; Nephrons* ; Phospholipases A2 ; Phosphorylation ; Protein Kinase C ; Rats, Inbred SHR ; Sodium ; Sodium-Potassium-Exchanging ATPase