scholarly journals VDR/Atg3 axis regulates slit diaphragm to tight junction transition via p62-mediated autophagy pathway in diabetic nephropathy

Diabetes ◽  
2021 ◽  
pp. db210205
Author(s):  
Bin Wang ◽  
Jing-yi Qian ◽  
Tao-tao Tang ◽  
Li-lu Lin ◽  
Nan Yu ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Tight Junction ◽  
Slit Diaphragm ◽  
Autophagy Pathway

scholarly journals VDR/Atg3 Axis Regulates Slit Diaphragm to Tight Junction Transition via p62-mediated Autophagy Pathway in Diabetic Nephropathy

2021 ◽  
Author(s):  
Bin Wang ◽  
Jing-yi Qian ◽  
Tao-tao Tang ◽  
Li-lu Lin ◽  
Nan Yu ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Tight Junction ◽  
Diabetic Animal ◽  
Slit Diaphragm ◽  
Autophagic Flux ◽  
The Novel ◽  
Foot Process ◽  
Autophagy Pathway ◽  
And Function ◽  
Early Diabetic Nephropathy

Foot process effacement is an important feature of early diabetic nephropathy (DN) which is closely related to the development of albuminuria. Under certain nephrotic conditions, the integrity and function of the glomerular slit diaphragm (SD) structure were impaired and replaced by the tight junction (TJ) structure, resulting in so-called SD-TJ transition, which could partially explain the effacement of foot processes at the molecular level. However, the mechanism underlying the SD-TJ transition has not been described in DN. Here, we demonstrated that impaired autophagic flux blocked p62 mediated degradation of ZO-1 (TJ protein) and promoted podocytes injury via activation of caspase 3 and caspase 8. Interestingly, the expression of VDR in podocytes was decreased under diabetic condition which impaired autophagic flux through down-regulating Atg3. Of note, we also found that VDR abundance was negatively associated with impaired autophagic flux and SD-TJ transition in the glomeruli from human renal biopsy samples with DN. Furthermore, VDR activation improved autophagic flux and attenuated SD-TJ transition in the glomeruli of diabetic animal models. In conclusion, our data provided the novel insight that VDR/Atg3 axis deficiency resulted in SD-TJ transition and foot processes effacement via blocking p62-mediated autophagy pathway in DN.<br>

scholarly journals VDR/Atg3 Axis Regulates Slit Diaphragm to Tight Junction Transition via p62-mediated Autophagy Pathway in Diabetic Nephropathy

2021 ◽  
Author(s):  
Bin Wang ◽  
Jing-yi Qian ◽  
Tao-tao Tang ◽  
Li-lu Lin ◽  
Nan Yu ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Tight Junction ◽  
Diabetic Animal ◽  
Slit Diaphragm ◽  
Autophagic Flux ◽  
The Novel ◽  
Foot Process ◽  
Autophagy Pathway ◽  
And Function ◽  
Early Diabetic Nephropathy

Foot process effacement is an important feature of early diabetic nephropathy (DN) which is closely related to the development of albuminuria. Under certain nephrotic conditions, the integrity and function of the glomerular slit diaphragm (SD) structure were impaired and replaced by the tight junction (TJ) structure, resulting in so-called SD-TJ transition, which could partially explain the effacement of foot processes at the molecular level. However, the mechanism underlying the SD-TJ transition has not been described in DN. Here, we demonstrated that impaired autophagic flux blocked p62 mediated degradation of ZO-1 (TJ protein) and promoted podocytes injury via activation of caspase 3 and caspase 8. Interestingly, the expression of VDR in podocytes was decreased under diabetic condition which impaired autophagic flux through down-regulating Atg3. Of note, we also found that VDR abundance was negatively associated with impaired autophagic flux and SD-TJ transition in the glomeruli from human renal biopsy samples with DN. Furthermore, VDR activation improved autophagic flux and attenuated SD-TJ transition in the glomeruli of diabetic animal models. In conclusion, our data provided the novel insight that VDR/Atg3 axis deficiency resulted in SD-TJ transition and foot processes effacement via blocking p62-mediated autophagy pathway in DN.<br>

P0989VDR/ATG3 AXIS REGULATES SLIT DIAGRAM TO TIGHT JUNCTION TRANSITION VIA P62-MEDIATED AUTOPHAGY PATHWAY IN DIABETIC NEPHROPATHY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Jingyi Qian ◽  
Bin Wang ◽  
Bicheng Liu
Keyword(s):  
Diabetic Nephropathy ◽  
Tight Junction ◽  
Degradation Pathway ◽  
Serum Starvation ◽  
Autophagic Flux ◽  
Vdr Gene ◽  
Podocyte Injury ◽  
Autophagy Pathway

Abstract Background and Aims Vitamin D receptor (VDR) loss, slit diagram (SD) to tight junction (TJ) transition and impaired autophagic flux contribute to podocyte injury in diabetic nephrology. This study aims to examine the effect and mechanism of VDR on autophagic flux and SD-TJ transition in diabetic nephropathy. Method Renal biopsy tissues from DN patients at stage IIa, IIb, III, IV and patients with minimal lesions were used to evaluate the expression of VDR, autophagic flux and SD-TJ transition glomeruli. In vitro, cultured podocytes were treated with serum starvation (SS), autophagic inhibitors (3-methyladenine 3-MA or chloroquine CQ) to determine the degradation pathway of TJ marker ZO-1. Meanwhile, db/db mice and STZ-induced rats were used to explore the therapeutic effect and mechanism of VDR agonist in diabetic nephropathy. Results SD-TJ transition between foot processes could be observed under electron microscopy in DN patients at all stages, whereas foot processes were separated by the filtration slit and appeared to be single cross-strands in the normal glomeruli. There was a trend of increasing expression of autophagic marker p62 and ZO-1 and the expression of p62 is positively correlated with the changes of ZO-1 in the glomeruli of DN patients. In vitro, inhibiting autophagy with 3-MA and CQ resulted in the accumulation of ZO-1 in cultured podocytes. In addition, Co-IP experiments further convinced the interaction between p62 and ZO-1, which was enhanced by the activation of autophagy. Podocytes apoptosis and the activity of caspase 3 and caspase 8 were significantly increased in the presence of 3-MA or CQ, while these effects were rescued by silencing p62. According to VDR gene expression data in GEO database, VDR expression was decreased in diabetic nephropathy patients compared with normal people. Knocking down VDR lowered the expression of atg3 and leaded to the blockage of autophagy, which could be reversed by over-expressing Atg3. Podocytes treated with high glucose resulted in the decrease of VDR and Atg3, impaired autophagic flux and aggravated podocytes injury. However, VDR agonist treatment partially reversed all the changes. In vivo, db/db mice and STZ-induced rats (DN animal models) exhibited SD-TJ transition, massive proteinuria, decreased expression of VDR and podocin and the increased accumulation of p62 and ZO-1, all of which could be partially reversed by VDR agonist. Conclusion VDR loss contributed to the impairment of autophagic flux and SD-TJ transition via down-regulation Atg3 in diabetic nephropathy. Here, we identified a new mechanism and evidence for VDR agonist to treat diabetic nephropathy.

scholarly journals The tight junction protein ZO-1 is concentrated along slit diaphragms of the glomerular epithelium.

1990 ◽  
Vol 111 (3) ◽  
pp. 1255-1263 ◽  
Author(s):  
E Schnabel ◽  
J M Anderson ◽  
M G Farquhar
Keyword(s):  
Tight Junction ◽  
Rat Kidney ◽  
Freeze Fracture ◽  
Kidney Tissue ◽  
Slit Diaphragm ◽  
Kidney Cortex ◽  
Adult Rats ◽  
Junction Protein ◽  
Collecting Tubules ◽  
Lateral Cell

The foot processes of glomerular epithelial cells of the mammalian kidney are firmly attached to one another by shallow intercellular junctions or slit diaphragms of unknown composition. We have investigated the molecular nature of these junctions using an antibody that recognizes ZO-1, a protein that is specific for the tight junction or zonula occludens. By immunoblotting the affinity purified anti-ZO-1 IgG recognizes a single 225-kD band in kidney cortex and in slit diaphragm-enriched fractions as in other tissues. When ZO-1 was localized by immunofluorescence in kidney tissue of adult rats, the protein was detected in epithelia of all segments of the nephron, but the glomerular epithelium was much more intensely stained than any other epithelium. Among tubule epithelia the signal for ZO-1 correlated with the known fibril content and physiologic tightness of the junctions, i.e., it was highest in distal and collecting tubules and lowest in the proximal tubule. By immunoelectron microscopy ZO-1 was found to be concentrated on the cytoplasmic surface of the tight junctional membrane. Within the glomerulus ZO-1 was localized predominantly in the epithelial foot processes where it was concentrated precisely at the points of insertion of the slit diaphragms into the lateral cell membrane. Its distribution appeared to be continuous along the continuous slit membrane junction. When ZO-1 was localized in differentiating glomeruli in the newborn rat kidney, it was present early in development when the apical junctional complexes between presumptive podocytes are composed of typical tight and adhering junctions. It remained associated with these junctions during the time they migrate down the lateral cell surface, disappear and are replaced by slit diaphragms. The distribution of ZO-1 and the close developmental relationship between the two junctions suggest that the slit diaphragm is a variant of the tight junction that shares with it at least one structural protein and the functional property of defining distinctive plasmalemmal domains. The glomerular epithelium is unique among renal epithelia in that ZO-1 is present, but the intercellular spaces are wide open and no fibrils are seen by freeze fracture. The presence of ZO-1 along slit membranes indicates that expression of ZO-1 alone does not lead to tight junction assembly.

scholarly journals Association analysis of podocyte slit diaphragm genes as candidates for diabetic nephropathy

Diabetologia ◽  
2007 ◽  
Vol 51 (1) ◽  
pp. 86-90 ◽  
Author(s):  
P. Ihalmo ◽  
M. Wessman ◽  
M. A. Kaunisto ◽  
R. Kilpikari ◽  
M. Parkkonen ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Association Analysis ◽  
Slit Diaphragm

scholarly journals Glomerular clusterin expression is increased in diabetic nephropathy and protects against oxidative stress-induced apoptosis in podocytes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Junling He ◽  
Kyra L. Dijkstra ◽  
Kim Bakker ◽  
Pascal Bus ◽  
Jan A. Bruijn ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Diabetic Nephropathy ◽  
Mrna Expression ◽  
Kidney Diseases ◽  
Slit Diaphragm ◽  
Oxidative Stress Marker ◽  
Induced Apoptosis ◽  
Vitro Analysis ◽  
Clusterin Expression

Abstract Clusterin, a glycoprotein encoded by the CLU gene, is expressed in many tissues, including the kidney, and clusterin expression is upregulated in the glomeruli of patients with various forms of kidney disease. Here, we investigated the role of clusterin in diabetic nephropathy (DN). In this study, we found that glomerular clusterin expression was increased in both patients with DN and streptozotocin-induced diabetic mice and that it co-localised with the podocyte marker WT1, indicating clusterin is expressed in podocytes. In our in vitro analysis, we found no significant change in CLU mRNA expression in podocytes following stimulation with high glucose and angiotensin II; in contrast, CLU mRNA expression was significantly upregulated following methylglyoxal stimulation. Methylglyoxal treatment also significantly decreased the mRNA expression of the slit diaphragm markers ZO-1 and NEPH1 and significantly increased the mRNA expression of the oxidative stress marker HO-1. Lastly, we showed that pre-incubating podocytes with recombinant human clusterin protein increased podocyte survival, prevented slit diaphragm damage, and reduced oxidative stress‒induced apoptosis following methylglyoxal stimulation. Taken together, our results indicate that glomerular clusterin is upregulated in DN, and this increase in clusterin expression may protect against oxidative stress-induced apoptosis in podocytes, providing a possible new therapeutic target for DN and other kidney diseases.

scholarly journals The number of podocyte and slit diaphragm is decreased in experimental diabetic nephropathy

2006 ◽  
Vol 21 (2) ◽  
pp. 87-91 ◽  
Author(s):  
Mauro Masson Lerco ◽  
Célia Sperandéo Macedo ◽  
Reinaldo José Silva ◽  
Daniela de Oliveira Pinheiro ◽  
César Tadeu Spadella
Keyword(s):  
Body Weight ◽  
Diabetic Nephropathy ◽  
Diabetic Rats ◽  
Slit Diaphragm ◽  
Diabetic Rat ◽  
Severe Diabetes ◽  
Foot Process ◽  
The Right ◽  
Alloxan Injection

PURPOSE: To determine the number of podocyte, slit diaphragms, slit diaphragm extensions and GBM thickness in diabetic nephropathy. METHODS: Sixty "Rattus Wistar"of both sexes weighing 200-300g were divided in two experimental groups: normal group 10 animals, and alloxan diabetic rats - 50 animals. Alloxan was administered in a single IV dose of 42mg/kg body weight. Body weight, water and food intake, diuresis, and blood and urine glucose were determined in both groups before alloxan injection and two weeks, six and twelve months after alloxan injection. Proteinuria was measured at 12 months in both groups. After 12 months animals were sacrificed, and the right kidney processed for electron microscopy. RESULTS: Clear clinical and laboratory signs of severe diabetes were seen, in all alloxan-diabetic rats at all follow-up times. Glomerular basement membrane (GBM) thickening, podocyte number, and slit diaphragm number and extension were determined. GBM of all diabetic rats was significantly thicker (median=0.29µm; semi-interquartile range=0.065µm) than in the normal rats (0.23µm; 0.035µm). Diabetic rat podocyte number (8; 1), slit diaphragm number (4; 1), and slit diaphragm extension (0.021µm; 0.00435µm) were significantly lower than in normal rats (11; 1) and (7; 1.5), and (0.031µm; 0.0058µm). Diabetic rat proteinuria (0.060mg/24h; 0.037mg/24h) was higher than in normal rats (0.00185mg/24h; 0.00055mg/24h). CONCLUSION: Experimental diabetes is associated with significant (p<0.05) changes in podocyte foot process, slit number, slit diaphragm extension, and GBM thickness.

The Nature of the Intramembrane Particle

1980 ◽  
Vol 38 ◽  
pp. 688-691
Author(s):  
A.J. Verkleij
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Gap Junction ◽  
The Other ◽  
Fracture Face ◽  
Band 3 Protein ◽  
Satisfactory Explanation ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Luminal Membrane

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.

Sign in / Sign up

Export Citation Format

Share Document