Fetal podocyte

AIM: To explore the spatial and temporal expression patterns of DAB1 and Reelin in the developing and postnatal healthy human kidneys as potential determinants of kidney development. METHODS: Paraffin-embedded fetal kidney tissue between the 13/14th and 38th developmental weeks (dw) and postnatal tissue at 1.5 and 7 years were stained with DAB1 and Reelin antibodies by double immunofluorescence. RESULTS: During the fetal kidney development and postnatal period, DAB1 and Reelin showed specific spatial expression pattern and diverse fluorescence intensity...

Background The expression in the glomerular mesangial cells, papillary, and collecting duct cells demonstrated annexin A1 (AnxA1)'s role in specific renal functions. With varying concentrations of calcium (Ca2+), it is considered to regulate cellular processes such as cell proliferation, apoptosis, and clearance of apoptotic cells by forming ceramides, a key lipid mediator of apoptosis. It also participates in tumorigenesis based on its location. On account of these features, we investigated the expression of this apoptosis-associated protein in fetal kidneys at different gestational periods, mature kidneys and in kidney cancer tissues in order to localize and possibly characterize its role during nephrogenesis and renal tumors...

Analysis of kidney disease-causing genes and pathology resulting from systemic diseases highlight the importance of the kidney's filtering system, the renal corpuscles. To elucidate the developmental processes that establish the renal corpuscle, we performed single-nucleus droplet-based sequencing of the human fetal kidney. This enabled the identification of nephron, interstitial, and vascular cell types that together generate the renal corpuscles. Trajectory analysis identified transient developmental gene expression, predicting precursors or mature podocytes express FBLN2, BMP4, or NTN4, in conjunction with recruitment, differentiation, and modeling of vascular and mesangial cell types into a functional filter...

Thyroid hormone (TH) signaling is a universal regulator of metabolism, growth, and development. Here, we show that TH-TH receptor (TH-TR) axis alterations are critically involved in diabetic nephropathy-associated (DN-associated) podocyte pathology, and we identify TRα1 as a key regulator of the pathogenesis of DN. In ZSF1 diabetic rats, T3 levels progressively decreased during DN, and this was inversely correlated with metabolic and renal disease worsening. These phenomena were associated with the reexpression of the fetal isoform TRα1 in podocytes and parietal cells of both rats and patients with DN and with the increased glomerular expression of the TH-inactivating enzyme deiodinase 3 (DIO3)...

The glomerular podocyte is one of the major targets of kidney research. Recent establishment of kidney organoids from pluripotent stem cells has enabled the detailed analysis of human podocytes in both development and disease. The podocytes in organoids express slit diaphragm-related genes and proteins and exhibit characteristic morphology, especially upon experimental transplantation. Organoid technology is now used to reproduce hereditary podocyte diseases, and selective podocyte induction methods have also been reported...

The renal corpuscle of the kidney comprises a glomerular vasculature embraced by podocytes and supported by mesangial myofibroblasts, which ensure plasma filtration at the podocyte-generated slit diaphragm. With a spectrum of podocyte-expressed gene mutations causing chronic disease, an enhanced understanding of podocyte development and function to create relevant in vitro podocyte models is a clinical imperative. To characterize podocyte development, scRNA-seq was performed on human fetal kidneys, identifying distinct transcriptional signatures accompanying the differentiation of functional podocytes from progenitors...

IgG and albumin are the most abundant proteins in the circulation and have the longest half-lives. These properties are due to a unique receptor, the neonatal Fc receptor (FcRn). Although FcRn is named for its function of transferring IgG across the placenta from maternal to fetal circulation, FcRn functions throughout life to maintain IgG and albumin concentrations. FcRn protects IgG and albumin from intracellular degradation and recycles them back into the circulation. Clinical trials have confirmed that pathogenic antibodies can be depleted by blocking this homeostatic function of FcRn...

The current understanding of mammalian kidney development is largely based on mouse models. Recent landmark studies revealed pervasive differences in renal embryogenesis between mouse and human. The scarcity of detailed gene expression data in humans therefore hampers a thorough understanding of human kidney development and the possible developmental origin of kidney diseases. In this paper, we present a single-cell transcriptomics study of the human fetal kidney. We identified 22 cell types and a host of marker genes...

This study aimed to demonstrate that prenatal dexamethasone exposure (PDE) can induce kidney dysplasia in utero and adult glomerulosclerosis in male offspring, and to explore the underlying intrauterine programming mechanisms. Pregnant rats were subcutaneously administered dexamethasone 0.2 mg/kg.d from gestational day (GD) 9 to GD20. The male fetus on GD20 and the adult offspring at age of postnatal week 28 were analyzed. The adult offspring kidneys in the PDE group displayed glomerulosclerosis, elevated levels of serum creatinine and urine protein, ultrastructural damage of podocytes, the reduced expression levels of podocyte marker genes, nephrin and podocin...

Podocytes play a critical role in glomerular barrier function, both in health and disease. However, in vivo terminally differentiated podocytes are difficult to be maintained in in vitro culture. Induced pluripotent stem cells (iPSCs) offer the unique possibility for directed differentiation into mature podocytes. The current differentiation protocol to generate iPSC-derived podocyte-like cells provides a robust and reproducible method to obtain podocyte-like cells after 10 days that can be employed in in vitro research and biomedical engineering...

Podocyte is one of the main components of glomerular filtration barrier in the kidney; the loss or dysfunction of podocyte could impair the functions of glomerular filtration barrier, leading to development of various renal diseases. Podocyte is a terminally differentiated cell, and thus does not possess any proliferative properties. Accordingly, its number and contribution to renal function are initially determined by its normal development. Information from the literature and results of our research indicate that genetic factors or prenatal adverse environment could cause developmental retardation of podocytes, thereby suggesting the potential fetal developmental origin(s) of kidney diseases, and involvement of epigenetic mechanisms in the regulation of key genes in podocyte development...

The aim of this study was to determine the developmental characteristics of podocytes in the human fetal metanephros using scanning electron microscopy, light microscopy, and transmission electron microscopy. Kidney samples of 15 human fetuses of both sexes (gestational age 10-22 weeks) were analyzed. At the S-shaped body stage, primitive podocytes were arranged in a layer of cuboidal cells beneath the vascular cleft. When observed from Bowman's space, the demarcation between adjacent podocytes was not clear, but mild depressions indicated cell boundaries...

BACKGROUND: During normal human kidney development, nephrogenesis (the formation of nephrons) is complete by term birth, with the majority of nephrons formed late in gestation. The aim of this study was to morphologically examine nephrogenesis in fetal human kidneys from 20 to 41weeks of gestation. METHODS: Kidney samples were obtained at autopsy from 71 infants that died acutely in utero or within 24h after birth. Using image analysis, nephrogenic zone width, the number of glomerular generations, renal corpuscle cross-sectional area and the cellular composition of glomeruli were examined...

Highly organized cell processes characterize glomerular podocytes in vivo. However, podocytes in culture have a simple morphology lacking cell processes, especially upon reaching confluence. Here, we aimed to establish culture conditions under which cultured podocytes extend cell processes at confluence. Among various culture conditions that could possibly cause phenotypic changes in podocytes, we examined the effects of heparin, all-trans retinoic acid, fetal bovine serum, and extracellular matrices on the morphology of podocytes in rat primary culture...

Renal histologic expression of the podocyte-specific protein, nephrin, but not podocin, is reduced in preeclamptic compared with normotensive pregnancies. We hypothesized that renal expression of podocyte-specific proteins would be reflected in urinary extracellular vesicles (EVs) of podocyte origin and accompanied by increased urinary soluble nephrin levels (nephrinuria) in preeclampsia. We further postulated that podocyte injury and attendant formation of EVs are related mechanistically to cellfree fetal hemoglobin (HbF) in maternal plasma...

BACKGROUND: The number of nephrons at birth is determined during fetal development and is modulated thereafter by postnatal podocyte injury. Hyperfiltration, caused by a reduced number of nephrons, is a risk factor for chronic kidney disease. It is therefore important to monitor the formation of nephrons. METHODS: Urine samples were collected from infants within 1-2 days of birth, with follow-up sampling for preterm infants at 37-39 weeks of corrected age. Urinary levels of podocalyxin (PCX), β2-microglobulin (β2MG), N-acetyl-ß-D-glucosaminidase (NAG), total protein (TP), microalbumin (mAlb) and creatinine were measured and the relationship between these markers evaluated...

Angiopoietins and their TIE receptors are important regulators of vascular stability and remodeling. These molecules are involved not only in the normal development of kidney glomeruli, but also in disease, thus making them promising targets for therapies. Although TIE receptors are mainly found in endothelial cells, some reports observed TIE2 expression in glomerular podocytes as well. This suggests a role of angiopoietins in the regulation of podocytes. In the present study, we aimed to map the subcellular localization of TIE receptors in metanephric glomeruli of fetal pigs using high-resolution immunogold electron microscopy and the relative labeling index stereological approach...

Unbiased transcriptome profiling and functional genomics approaches have identified ubiquitin-specific protease 40 (USP40) as a highly specific glomerular transcript. This gene product remains uncharacterized, and its biological function is completely unknown. Here, we showed that mouse and rat glomeruli exhibit specific expression of the USP40 protein, which migrated at 150 kDa and was exclusively localized in the podocyte cytoplasm of the adult kidney. Double-labeling immunofluorescence staining and confocal microscopy analysis of fetal and neonate kidney samples revealed that USP40 was also expressed in the vasculature, including in glomerular endothelial cells at the premature stage...

Intussusceptive angiogenesis (IA) is required for normal embryonic vascular development. The Tie family of receptors and their ligands, the angiopoietins, play an important role in the growth or regression of blood vessels which are important not only during development but also throughout an organism's life. The presence of IA was investigated in glomerular capillaries of the fetal porcine metanephros using Mercox II resin casts. The first signs of IA were observed in stage III glomeruli. Stage IV and V glomeruli showed numerous signs of aligned pillar formation and their successive merging to delineate the vascular entities...

BACKGROUND: Collapsing Glomerulopathy (CG), also known as the collapsing variant of Focal Segmental Glomerulosclerosis (FSGS), is distinct in both its clinical severity and its pathophysiologic characteristics from other forms of FSGS. This lesion occurs disproportionally in patients carrying two APOL1 risk alleles, and is the classic histologic lesion resulting from Human Immunodeficiency Virus (HIV) infection of podocytes. Other viral infections, including parvovirus B19, and drugs such as interferon that perturb the immune system, have also been associated with CG...