scholarly journals Angiotensin-(3-4) modulates the overweight- and undernutrition-induced ACE2 downregulation in renal proximal tubule cells: implications for COVID-19?

Author(s):  
Rafael Luzes ◽  
Humberto Muzi-Filho ◽  
Amaury Pereira-Acácio ◽  
Thuany Crisóstomo ◽  
Adalberto Vieyra

Aim: The renal lesions–including severe acute kidney injury–are severe outcomes in severe acute respiratory syndrome coronavirus 2 infections. There are no reports regarding the influence of the nutritional status on the severity and progress of these lesions. Ageing is also an important risk factor. Methods: In the present study we compared the influence of overweight and undernutrition on the levels of renal angiotensin converting enzymes 1 and 2 (ACE and ACE2), which were evaluated by Western blotting. Since the renin-angiotensin-aldosterone system (RAAS) has been implicated in the progress of kidney failure during coronavirus disease 2019, the influence of Angiotensin-(3-4) [Ang-(3-4)] was investigated. Ang-(3-4) is the shortest angiotensin-derived peptide, which is considered the physiological antagonist of several Ang II effects. Results: Both overweight and undernutrition downregulate the levels of ACE2 without influence on the levels of ACE in proximal tubules from kidney rats. Administration of Ang-(3-4) upregulates ACE2 to levels above the control in overweight but not in undernourished rats. Conclusions: Chronic undernourishment and overnourishment conditions play a central role in the renal ACE/ACE2 balance, and that the role of RAAS is also different in overweight and undernutrition.

2020 ◽  
Author(s):  
Rafael Luzes ◽  
Humberto Muzi-Filho ◽  
Amaury Pereira-Acácio ◽  
Thuany Crisóstomo ◽  
Adalberto Vieyra

AbstractThe renal lesions – including severe acute kidney injury – are severe outcomes in SARS-CoV-2 infections. There are no reports regarding the influence of the nutritional status on the severity and progress of these lesions. Ageing is also an important risk factor. In the present communication we compare the influence of overweight and undernutrition in the levels of renal angiotensin converting enzymes 1 and 2. Since the renin-angiotensin-aldosterone system (RAAS) has been implicated in the progress of kidney failure during Covid-19, we also investigated the influence of Angiotensin-(3–4) (Ang-(3–4)) the shortest angiotensin-derived peptide, which is considered the physiological antagonist of several angiotensin II effects. We found that both overweight and undernutrition downregulate the levels of angiotensin converting enzyme 2 (ACE2) without influence on the levels of ACE1 in kidney rats. Administration of Ang-(3–4) recovers the control levels of ACE2 in overweight but not in undernourished rats. We conclude that chronic and opposite nutritional conditions play a central role in the pathophysiology of renal Covid-19 lesions, and that the role of RAAS is also different in overweight and undernutrition.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Ryousuke Satou ◽  
Kathleen S Hering-Smith ◽  
L G Navar

In angiotensin II (Ang II)-dependent hypertension, intrarenal angiotensinogen (AGT) augmentation induced by Ang II and associated pathogenic factors including interleukin 6 (IL-6) cause further elevation of intratubular Ang II production, leading to the progression of hypertension and kidney injury. Recent studies have suggested that renal proximal straight tubules (S3 segment) are the main source of intrarenal AGT and that S1 and S2 segments do not express AGT mRNA under normal conditions. However, AGT expression and its regulation by Ang II and/or IL-6 in each proximal tubule segment have not been demonstrated an in vitro setting. The availability of specific cell lines derived from mouse S1, S2 and S3 segments provided an opportunity to decisively determine each segments’ capability to express AGT and respond to stimuli. Thus, this study was performed to determine AGT expression and its response to stimulation with Ang II and IL-6 in S1, S2 and S3 cell line. Basal AGT mRNA and protein levels were detected by RT-PCR and western blot analysis. Basal levels of Ang II type 1 receptor (AT1R) and STAT3, which is a transcription factor in IL-6 signaling pathway, were also measured. In addition, the cells were incubated with 100 nM Ang II and/or 400 nM IL-6 for 24 h. Basal AGT levels in S1 and S3 cells were lower than in mouse whole kidney (0.09-fold and 0.33-fold compared with mouse whole kidney). S2 cells exhibited the highest basal AGT levels (4.15-fold) among these cells. In S1 cells, AGT expression was stimulated by IL-6 (1.89 ± 0.32, ratio to control) and co-stimulation with Ang II and IL-6 (1.85 ± 0.28) although Ang II alone did not alter AGT levels. In S2 cells, only the co-stimulation increased AGT expression (1.35 ± 0.01). No changes were observed by similar treatments in S3 cells. Basal AT1R levels were lower in S3 than in S1 and S2 cells (0.97 ± 0.09 in S2, 0.32 ± 0.07 in S3, ratio to S1). S1 cells showed the highest basal levels of STAT3. Basal STAT3 levels in S3 cells were lower than that in S1 and S2 cells. These results indicate that S2 cells are main source of intrarenal AGT which can be augmented by Ang II and IL-6 during the development of Ang II-dependent hypertension. Furthermore, low basal levels of AT1R and STAT3 in S3 cells explain why these cells do not respond to Ang II and IL-6.


2015 ◽  
Vol 308 (11) ◽  
pp. F1268-F1275 ◽  
Author(s):  
Yixin Su ◽  
Jianli Bi ◽  
Victor M. Pulgar ◽  
Jorge Figueroa ◽  
Mark Chappell ◽  
...  

We have shown a sex-specific effect of fetal programming on Na+ excretion in adult sheep. The site of this effect in the kidney is unknown. Therefore, we tested the hypothesis that renal proximal tubule cells (RPTCs) from adult male sheep exposed to betamethasone (Beta) before birth have greater Na+ uptake than do RPTCs from vehicle-exposed male sheep and that RPTCs from female sheep similarly exposed are not influenced by antenatal Beta. In isolated RPTCs from 1- to 1.5-yr-old male and female sheep, we measured Na+ uptake under basal conditions and after stimulation with ANG II. To gain insight into the mechanisms involved, we also measured nitric oxide (NO) levels, ANG II receptor mRNA levels, and expression of Na+/H+ exchanger 3. Basal Na+ uptake increased more in cells from Beta-exposed male sheep than in cells from vehicle-exposed male sheep (400% vs. 300%, P < 0.00001). ANG II-stimulated Na+ uptake was also greater in cells from Beta-exposed males. Beta exposure did not increase Na+ uptake by RPTCs from female sheep. NO production was suppressed more by ANG II in RPTCs from Beta-exposed males than in RPTCs from either vehicle-exposed male or female sheep. Our data suggest that one site of the sex-specific effect of Beta-induced fetal programming in the kidney is the RPTC and that the enhanced Na+ uptake induced by antenatal Beta in male RPTCs may be related to the suppression of NO in these cells.


2020 ◽  
Vol 21 (9) ◽  
pp. 3275 ◽  
Author(s):  
Manoocher Soleimani

Coronaviruses (CoVs), including Severe Acute Respiratory Syndrome (SARS), Middle East Respiratory Syndrome (MERS), and the novel coronavirus disease-2 (SARS-CoV-2) are a group of enveloped RNA viruses that cause a severe respiratory infection which is associated with a high mortality [...]


2019 ◽  
Vol 317 (3) ◽  
pp. F743-F756 ◽  
Author(s):  
Sang Jun Han ◽  
Mihwa Kim ◽  
Vivette D. D’Agati ◽  
H. Thomas Lee

Acute kidney injury (AKI) due to renal ischemia-reperfusion (I/R) is a major clinical problem without effective therapy. Ginger is one of the most widely consumed spices in the world, and 6-shogaol, a major ginger metabolite, has anti-inflammatory effects in neuronal and epithelial cells. Here, we demonstrate our novel findings that 6-shogaol treatment protected against renal I/R injury with decreased plasma creatinine, blood urea nitrogen, and kidney neutrophil gelatinase-associated lipocalin mRNA synthesis compared with vehicle-treated mice subjected to renal I/R. Additionally, 6-shogaol treatment reduced kidney inflammation (decreased proinflammatory cytokine and chemokine synthesis as well as neutrophil infiltration) and apoptosis (decreased TUNEL-positive renal tubular cells) compared with vehicle-treated mice subjected to renal I/R. In cultured human and mouse kidney proximal tubule cells, 6-shogaol significantly attenuated TNF-α-induced inflammatory cytokine and chemokine mRNA synthesis. Mechanistically, 6-shogaol significantly attenuated TNF-α-induced NF-κB activation in human renal proximal tubule cells by reducing IKKαβ/IκBα phosphorylation. Furthermore, 6-shogaol induced a cytoprotective chaperone heme oxygenase (HO)-1 via p38 MAPK activation in vitro and in vivo. Consistent with these findings, pretreatment with the HO-1 inhibitor zinc protoporphyrin IX completely prevented 6-shogaol-mediated protection against ischemic AKI in mice. Taken together, our study showed that 6-shogaol protects against ischemic AKI by attenuating NF-κB activation and inducing HO-1 expression. 6-Shogaol may provide a potential therapy for ischemic AKI during the perioperative period.


2006 ◽  
Vol 290 (6) ◽  
pp. F1382-F1390 ◽  
Author(s):  
Jia L. Zhuo ◽  
Xiao C. Li ◽  
Jeffrey L. Garvin ◽  
L. Gabriel Navar ◽  
Oscar A. Carretero

Intracellular ANG II induces biological effects in nonrenal cells, but it is not known whether it plays a physiological role in renal proximal tubule cells (PTCs). PTCs express angiotensinogen, renin, and angiotensin-converting enzyme mRNAs, suggesting the presence of high levels of intracellular ANG II. We determined if microinjection of ANG II directly in single PTCs increases intracellular calcium concentration ([Ca2+]i) and, if so, elucidated the cellular mechanisms involved. Changes in [Ca2+]i responses were studied by fluorescence imaging using the Ca2+ indicator fluo 3. ANG II (1 nM) was microinjected directly in the cells, whereas cell-surface angiotensin type 1 (AT1) receptors were blocked by losartan (10 μM). When ANG II (1 nM) was added to the perfusate, there was a marked increase in [Ca2+]i that was blocked by extracellular losartan. With losartan in the perfusate, intracellular microinjection of ANG II elicited a robust increase in cytoplasmic [Ca2+]i that peaked at 30 s (basal: 2.2 ± 0.3 vs. ANG II: 14.9 ± 0.4 relative fluorescence units; P < 0.01). Chelation of extracellular Ca2+ with EGTA (2 mM) did not alter microinjected ANG II-induced [Ca2+]i responses (Ca2+ free + ANG II: 12.3 ± 2.6 relative fluorescence units, not significant vs. ANG II); however, pretreatment with thapsigargin to deplete intracellular Ca2+ stores or with U-73122 to inhibit phospholipase C (1 μM each) markedly attenuated microinjected ANG II-induced [Ca2+]i responses. Combined microinjection of ANG II and losartan abolished [Ca2+]i responses, whereas a combination of ANG II and PD-123319 had no effect. These data demonstrate for the first time that direct microinjection of ANG II in single PTCs increases [Ca2+]i by stimulating intracellular AT1 receptors and releases Ca2+ from intracellular stores, suggesting that intracellular ANG II may play a physiological role in PTC function.


2019 ◽  
Author(s):  
Selim Rozyyev ◽  
Annabelle P. Crusan ◽  
Andrew C. Tiu ◽  
Julie A. Jurgens ◽  
Justin Michael B. Quion ◽  
...  

ABSTRACTThe peripheral dopaminergic system promotes the maintenance of blood pressure homeostasis by engendering natriuresis, mainly through the renal D1R and D5R receptors. This effect is most apparent under conditions of moderate body sodium excess. Human and rodent renal proximal tubules express both receptors, which share common structural features and pharmacological profiles. Genetic ablation of either receptor in the kidney results in hypertension in mice. In this study, we demonstrated that in renal proximal tubules, these two receptors colocalized, co-immunoprecipitated, co-segregated in lipid rafts, and heterodimerized with one another, which was enhanced by treatment with the D1R/D5R agonist fenoldopam (1 μM, 30 min). Gene silencing via antisense oligonucleotides in renal proximal tubule cells abrogated cAMP production and sodium transport in response to fenoldopam. Our results highlight the cooperation and co-dependence of these two receptors through heterodimerization in renal proximal tubule cells.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Eleni Stamellou ◽  
Mingbo Cheng ◽  
Viktor Sterzer ◽  
Katja Leuchtle ◽  
Thiago Strieder ◽  
...  

Abstract Background and Aims Acute tubular injury accounts for the most common intrinsic cause for acute kidney injury (AKI). The scattered tubular cell (STC) phenotype was discovered as a uniform reaction of tubule cells triggered by injury. Our group was the first to identify an inducible transgenic mouse (PEC-rtTA-mouse) specifically labeling STCs with eGFP. Analysis of the transcriptional factors and associated signaling pathways might reveal the function and role of STCs in AKI. Method Here, we performed single-cell RNA sequencing of unilateral ischemia-reperfusion murine model of AKI 8, 24, 48 hours and 6 and 12 days after AKI induction. Results Genes expressing proximal tubular proteins and transporters were markedly downregulated during transition into the STC phenotype upon injury; but expression recovered over time and upon resolution and tubular cells re-differentiated into proximal tubule cells. This provides evidence for the first time that the STC phenotype is a transient and reversible phenotype triggered by injury. Among cells in the STC phenotype, we could identify 2 sub-clusters; a highly proliferating sub-cluster that in the cell cycle analysis showed the highest proportion of cycling cells. The second eGFP-positive cluster appeared very early after AKI and expressed a distinct set of genes (defined by 7 anchor genes). Some of the highly up-regulated genes are known markers of STCs hence confirming the specificity of our transgenic mouse line. Conclusion Our study provides gene expression patterns specifically in STCs upon injury and repair at multiple time points and suggests that the STC phenotype is a transient and reversible phenotype triggered by injury.


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