mortality/aging
• heterozygous matings yield homozygotes at a reduced Mendelian ratio (17% vs expected 25%)
• however, viability is normal after birth
|
renal/urinary system
• glomerular cysts first develop at 3 months of age; they are distributed throughout the cortex area and are characterized by enlarged Bowman's space lined by flattened PECs and retracted capillary tufts
• % of glomeruli with cystic changes is significantly increased at 6 months and also at 12 months
• however, glomerulotubular junction is preserved in glomeruli with cystic change
|
• no significant increase in urine osmolality under water deprivation at 6 months of age, indicating a urinary concentration defect
|
• mild but significant increase in urine albumin/creatinine ratio at 6 and 12 months of age
|
albuminuria
(
J:240798
)
• at P0, mean urinary albumin concentration is 942.0 +/- 507.5 mg/l versus 34.6 +/- 7.8 in wild-type controls
• urine albumin excretion is progressively reduced during the first week of age, with recovery of the glomerular and tubular lesions at P7
|
• numerous urinary dysmorphic erythrocytes found at P0, suggestive of glomerular origin
|
• expansion of the stroma component between ducts at P0
|
• flattened epithelium in the collecting ducts at P0
|
• widening of the collecting duct lumen in the medulla at P0
|
• adult mice show thickening and multilamination of the Bowman's capsule at 6 months of age
• abnormal Bowman's capsule structure is associated with metalloproteinase induction and activation of the glomerular parietal epithelial cells
|
• glomerular parietal epithelial cells (PECs) show an activated phenotype (overexpression of claudin-1 and induction of CD44), induction of DDR1 (discoidin domain receptors 1), and activation of integrin-linked kinase (ILK) pathway at 1 month of age, prior to the development of glomerular cysts and periglomerular inflammation
|
• at 1 month of age, PECs in a subset (~15%) of glomeruli appear cube-shaped with enlarged nuclei, instead of forming a monolayer of thin epithelial cells with flat nuclei as in normal PECs
• enlarged cuboid PECs with enlarged nuclei are found lining the Bowman's capsule in about one-third of non-cystic glomeruli at 6 and 12 months of age
|
• enlarged Bowman's spaces with retracted capillary tufts found in a subset of glomeruli at P0
|
• podocyte disorganization in immature glomeruli after the formation of the first capillary loops, with podocytes arranging in multilayers instead of forming a regular layer
• focal persistence of large intercellular junctions between podocytes at P0
• integrin-linked kinase (ILK) expression is strongly enhanced in podocytes at 1 and 6 months of age
|
• extensive podocyte foot process effacement in mature glomeruli at P0
|
• expression of nephrin is dramatically reduced in glomeruli at P0; although occasionally detected in slit diaphragms, nephrin is abnormally localized in cytoplasmic vacuoles (vesicles) within the podocytes
• in contrast, podocin is normally expressed in the basal region of the podocytes along the GBM
|
• segmental duplication of the glomerulus basement membrane (GBM) at P0
• however, GBM and the tubular BM appear normal at 6 months of age
|
• glomerulogenesis is delayed after the formation of the first capillary loops, with defective GBM and podocyte maturation resulting in neonatal glomerular hyperpermeability
• neonate glomerular defects are resolved within the first month of life, but glomerular cysts develop at 3 months of age
• adult mice develop glomerulocystic kidney disease; however, no glomerular crescent or sclerotic segment of the glomerular tuft is observed
|
• dilated glomerular capillaries found in mature glomeruli in the deep cortex at P0
|
• integrin-linked kinase (ILK) expression is strongly enhanced in the mesangium at 1 and 6 months of age
|
• newborns display delayed glomerulogenesis and podocyte differentiation without reduction of nephron number
• however, neonate kidney defects do not result in a decreased glomerular density in adult mice
|
• dysmorphic kidney papilla at 6 months of age
|
• dilated proximal tubular sections with flattened epithelial cells at P0
• intracytoplasmic eosinophilic vacuoles in proximal tubular cells
|
• focal dilation with flattened proximal tubule cells at P0
|
renal cast
(
J:240798
)
• erythrocyte casts found in tubular sections at P0 and persisting at P7
• however, no casts are observed at 1 month of age
|
• in situ gelatin zymography revealed enhanced matrix metalloproteinase (MMP) enzymatic activity in the periglomerular region and around the renal tubules at 6 months of age
• pretreatment of renal tissue with EDTA, a specific inhibitor of MMP2 and MMP9, blocked gelanolytic activity
|
• inflammatory infiltrates are first detected in the kidney at 3 months of age
• at 12 months of age, periglomerular and perivascular inflammatory infiltrates are mostly composed by T-lymphocytes surrounded by macrophages
• however, no significant fibrosis is noted, except in inflammatory areas, and tubules remain normal at 12 months
|
• polyuria both under basal and water deprivation conditions at 6 months of age
|
homeostasis/metabolism
• significant increase of serum urea at 6 months but not at 12 months of age
|
• expression of the mutant alpha1alpha1alpha2(IV) trimer is reduced in newborn kidneys at P0, but remains detectable in the mesangium, Bowmans capsule, tubular BM, and GBM, indicating partially altered alpha1alpha1alpha2(IV) secretion
|
• no significant increase in urine osmolality under water deprivation at 6 months of age, indicating a urinary concentration defect
|
• mild but significant increase in urine albumin/creatinine ratio at 6 and 12 months of age
|
albuminuria
(
J:240798
)
• at P0, mean urinary albumin concentration is 942.0 +/- 507.5 mg/l versus 34.6 +/- 7.8 in wild-type controls
• urine albumin excretion is progressively reduced during the first week of age, with recovery of the glomerular and tubular lesions at P7
|
• numerous urinary dysmorphic erythrocytes found at P0, suggestive of glomerular origin
|
immune system
• inflammatory infiltrates are first detected in the kidney at 3 months of age
• at 12 months of age, periglomerular and perivascular inflammatory infiltrates are mostly composed by T-lymphocytes surrounded by macrophages
• however, no significant fibrosis is noted, except in inflammatory areas, and tubules remain normal at 12 months
|
growth/size/body
• significantly reduced mean body weight in both sexes at 6 and 12 months of age
• however, mean kidney weight is normal at both ages
|
• glomerular cysts first develop at 3 months of age; they are distributed throughout the cortex area and are characterized by enlarged Bowman's space lined by flattened PECs and retracted capillary tufts
• % of glomeruli with cystic changes is significantly increased at 6 months and also at 12 months
• however, glomerulotubular junction is preserved in glomeruli with cystic change
|
cardiovascular system
• dilated glomerular capillaries found in mature glomeruli in the deep cortex at P0
|
• adults exhibit retinal tortuosity
|
• newborns exhibit brain hemorrhages
|
muscle
• adults exhibit muscular dystrophy
|
nervous system
• newborns exhibit brain hemorrhages
|
vision/eye
• adults exhibit retinal tortuosity
|
Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
kidney disease | DOID:557 | J:240798 |