In Vivo Assessment of Diabetic Kidney Disease using Ultrasound Localization Microscopy

Renal magnetic resonance imaging (MRI) techniques are currently in vogue, as they provide in vivo information on renal volume, function, metabolism, perfusion, oxygenation, and microstructural alterations, without the need for exogenous contrast media. New imaging biomarkers can be identified using these tools, which represent a major advance in the understanding and study of the different pathologies affecting the kidney. Diabetic kidney disease (DKD) is one of the most important diseases worldwide due to its high prevalence and impact on public health. However, its multifactorial etiology poses a challenge for both basic and clinical research. Therefore, the use of novel renal MRI techniques is an attractive step forward in the comprehension of DKD, both in its pathogenesis and in its detection and surveillance in the clinical practice. This review article outlines the most promising MRI techniques in the study of DKD, with the purpose of stimulating their clinical translation as possible tools for the diagnosis, follow-up, and monitoring of the clinical impacts of new DKD treatments.

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Proteoglycans contribute to the functional integrity of the glomerular endothelial cell surface layer and are regulated in diabetic kidney disease

Scientific Reports ◽

10.1038/s41598-021-87753-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alina Khramova ◽

Roberto Boi ◽

Vincent Fridén ◽

Anna Björnson Granqvist ◽

Ulf Nilsson ◽

...

Keyword(s):

Surface Layer ◽

Kidney Disease ◽

Cell Surface ◽

Diabetic Kidney Disease ◽

Exchange Chromatography ◽

Diabetic Kidney ◽

Endothelial Cell Surface ◽

Filtration Barrier ◽

Essential Components

AbstractAll capillary endothelia, including those of the glomeruli, have a luminal cell surface layer (ESL) consisting of glycoproteins, glycolipids, proteoglycans (PGs) and glycosaminoglycans. Previous results have demonstrated that an intact ESL is necessary for a normal filtration barrier and damage to the ESL coupled to proteinuria is seen for example in diabetic kidney disease (DKD). We used the principles of ion exchange chromatography in vivo to elute the highly negatively charged components of the ESL with a 1 M NaCl solution in rats. Ultrastructural morphology and renal function were analyzed and 17 PGs and hyaluronan were identified in the ESL. The high salt solution reduced the glomerular ESL thickness, led to albuminuria and reduced GFR. To assess the relevance of ESL in renal disease the expression of PGs in glomeruli from DKD patients in a next generation sequencing cohort was investigated. We found that seven of the homologues of the PGs identified in the ESL from rats were differently regulated in patients with DKD compared to healthy subjects. The results show that proteoglycans and glycosaminoglycans are essential components of the ESL, maintaining the permselective properties of the glomerular barrier and thus preventing proteinuria.

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miR-379 deletion ameliorates features of diabetic kidney disease by enhancing adaptive mitophagy via FIS1

Communications Biology ◽

10.1038/s42003-020-01516-w ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Mitsuo Kato ◽

Maryam Abdollahi ◽

Ragadeepthi Tunduguru ◽

Walter Tsark ◽

Zhuo Chen ◽

...

Keyword(s):

Kidney Disease ◽

Diabetic Kidney Disease ◽

Mesangial Cells ◽

Mitochondrial Fission ◽

Major Complication ◽

Body Weight Loss ◽

Diabetic Kidney ◽

Guide Rna ◽

And Oxidative Stress

AbstractDiabetic kidney disease (DKD) is a major complication of diabetes. Expression of members of the microRNA (miRNA) miR-379 cluster is increased in DKD. miR-379, the most upstream 5′-miRNA in the cluster, functions in endoplasmic reticulum (ER) stress by targeting EDEM3. However, the in vivo functions of miR-379 remain unclear. We created miR-379 knockout (KO) mice using CRISPR-Cas9 nickase and dual guide RNA technique and characterized their phenotype in diabetes. We screened for miR-379 targets in renal mesangial cells from WT vs. miR-379KO mice using AGO2-immunopreciptation and CLASH (cross-linking, ligation, sequencing hybrids) and identified the redox protein thioredoxin and mitochondrial fission-1 protein. miR-379KO mice were protected from features of DKD as well as body weight loss associated with mitochondrial dysfunction, ER- and oxidative stress. These results reveal a role for miR-379 in DKD and metabolic processes via reducing adaptive mitophagy. Strategies targeting miR-379 could offer therapeutic options for DKD.

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Abstract 016: Profound and Sustained Amplification of Circulating ACE2 Activity Does Not Protect Diabetic Mice from Kidney Disease

Hypertension ◽

10.1161/hyp.66.suppl_1.016 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Jan Wysocki ◽

Minghao Ye ◽

Ahmed M Khattab ◽

Yashpal Kanwar ◽

Mark Osborn ◽

...

Keyword(s):

Kidney Disease ◽

Diabetic Kidney Disease ◽

Kidney Injury ◽

Renin Angiotensin System ◽

Diabetic Mice ◽

Diabetic Kidney ◽

Over Expression ◽

Akita Mice

ACE2 is a monocarboxypeptidase that by converting AngII to Ang1-7 should down-regulate the renin-angiotensin system and therefore provide a means to therapeutically target diabetic kidney disease, a condition where the kidney RAS is overactive. Previous work indicated that soluble human recombinant (r)ACE2 administration for 4 weeks attenuated kidney injury in diabetic Akita mice. Whether such effect of rACE2 can be confirmed and attributed to augmented ACE2 activity is uncertain because chronic use of human rACE2 in mice induces immunogenicity and the development of antibodies that neutralize serum ACE2 activity. To examine the effect of chronic amplification of circulating ACE2 on kidney injury caused by STZ-induced diabetes and to circumvent the immunogenicity arising from xenogeneic ACE2, ACE2 of mouse origin was administered to mice using either daily i.p. injections (1 mg/kg) of mrACE2 for 4 weeks or after 20 weeks of ACE2 mini-circle (MC) (10-30ug/mouse) administration. MC provides a form of gene delivery that is resistant to gene silencing and, in addition, greatly optimizes long-term in vivo overexpression of proteins of interest. ACE2MC resulted in a profound and sustained increase in serum ACE2 activity (2.4±0.3 vs. 497±135 RFU/ul/hr, p<0.01) but kidney ACE2 activity was unchanged (17.4±1.3 vs. 19.0±0.8 RFU/ug prot/hr). mACE2-treated mice injected with STZ developed diabetes similar to sham mice injected with STZ. Systolic BP was not different between non-diabetic mice, sham STZ-mice, and STZ-mice receiving mACE2 by either i.p. mrACE2 or ACE2MC. Urinary albumin was similarly increased in sham STZ-mice and in STZ-mice receiving mACE2. Glomerular mesangial score and glomerular cellularity were both increased to a similar extent in sham STZ-mice and in STZ-mice with mACE2 administration, as compared to non-diabetic controls. In conclusion, profound and long-term augmentation of ACE2 activity confined to the circulation is not sufficient to attenuate glomerular pathology and albuminuria in STZ-induced diabetic kidney disease probably because of lack of kidney delivery of ACE2. Strategies to achieve over-expression of ACE2 at the kidney level are needed to demonstrate a beneficial effect of this enzyme on diabetic kidney disease.

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Inflammation and Oxidative Stress in Diabetic Kidney Disease: The Targets for SGLT2 Inhibitors and GLP-1 Receptor Agonists

International Journal of Molecular Sciences ◽

10.3390/ijms221910822 ◽

2021 ◽

Vol 22 (19) ◽

pp. 10822

Author(s):

Agata Winiarska ◽

Monika Knysak ◽

Katarzyna Nabrdalik ◽

Janusz Gumprecht ◽

Tomasz Stompór

Keyword(s):

Oxidative Stress ◽

Kidney Disease ◽

Diabetic Kidney Disease ◽

Kidney Injury ◽

Organ Protection ◽

In Vivo Models ◽

Diabetic Kidney ◽

And Oxidative Stress

The incidence of type 2 diabetes (T2D) has been increasing worldwide, and diabetic kidney disease (DKD) remains one of the leading long-term complications of T2D. Several lines of evidence indicate that glucose-lowering agents prevent the onset and progression of DKD in its early stages but are of limited efficacy in later stages of DKD. However, sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor (GLP-1R) antagonists were shown to exert nephroprotective effects in patients with established DKD, i.e., those who had a reduced glomerular filtration rate. These effects cannot be solely attributed to the improved metabolic control of diabetes. In our review, we attempted to discuss the interactions of both groups of agents with inflammation and oxidative stress—the key pathways contributing to organ damage in the course of diabetes. SGLT2i and GLP-1R antagonists attenuate inflammation and oxidative stress in experimental in vitro and in vivo models of DKD in several ways. In addition, we have described experiments showing the same protective mechanisms as found in DKD in non-diabetic kidney injury models as well as in some tissues and organs other than the kidney. The interaction between both drug groups, inflammation and oxidative stress appears to have a universal mechanism of organ protection in diabetes and other diseases.

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Role of TGF-alpha in the progression of diabetic kidney disease

AJP Renal Physiology ◽

10.1152/ajprenal.00443.2016 ◽

2017 ◽

Vol 312 (6) ◽

pp. F951-F962 ◽

Cited By ~ 7

Author(s):

Josef G. Heuer ◽

Shannon M. Harlan ◽

Derek D. Yang ◽

Dianna L. Jaqua ◽

Jeffrey S. Boyles ◽

...

Keyword(s):

Kidney Disease ◽

Renal Disease ◽

Neutralizing Antibodies ◽

Diabetic Kidney Disease ◽

Transforming Growth Factor ◽

Renin Angiotensin System ◽

Neutralizing Antibody ◽

Diabetic Kidney

Transforming growth factor-alpha (TGFA) has been shown to play a role in experimental chronic kidney disease associated with nephron reduction, while its role in diabetic kidney disease (DKD) is unknown. We show here that intrarenal TGFA mRNA expression, as well as urine and serum TGFA, are increased in human DKD. We used a TGFA neutralizing antibody to determine the role of TGFA in two models of renal disease, the remnant surgical reduction model and the uninephrectomized (uniNx) db/db DKD model. In addition, the contribution of TGFA to DKD progression was examined using an adeno-associated virus approach to increase circulating TGFA in experimental DKD. In vivo blockade of TGFA attenuated kidney disease progression in both nondiabetic 129S6 nephron reduction and Type 2 diabetic uniNx db/db models, whereas overexpression of TGFA in uniNx db/db model accelerated renal disease. Therapeutic activity of the TGFA antibody was enhanced with renin angiotensin system inhibition with further improvement in renal parameters. These findings suggest a pathologic contribution of TGFA in DKD and support the possibility that therapeutic administration of neutralizing antibodies could provide a novel treatment for the disease.

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Qing-Re-Xiao-Zheng Formula Modulates Gut Microbiota and Inhibits Inflammation in Mice With Diabetic Kidney Disease

Frontiers in Medicine ◽

10.3389/fmed.2021.719950 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yabin Gao ◽

Ruibing Yang ◽

Lan Guo ◽

Yaoxian Wang ◽

Wei Jing Liu ◽

...

Keyword(s):

Kidney Disease ◽

Gut Microbiota ◽

Diabetic Kidney Disease ◽

Inflammatory Responses ◽

Protective Effects ◽

Mice Model ◽

Diabetic Kidney ◽

Metabolic Inflammation ◽

Gut Microbiota Dysbiosis

Evidence indicates that the metabolic inflammation induced by gut microbiota dysbiosis contributes to diabetic kidney disease. Prebiotic supplementations to prevent gut microbiota dysbiosis, inhibit inflammatory responses, and protect the renal function in DKD. Qing-Re-Xiao-Zheng formula (QRXZF) is a Traditional Chinese Medicine (TCM) formula that has been used for DKD treatment in China. Recently, there are growing studies show that regulation of gut microbiota is a potential therapeutic strategy for DKD as it is able to reduce metabolic inflammation associated with DKD. However, it is unknown whether QRXZF is effective for DKD by regulating of gut microbiota. In this study, we investigated the reno-protective effect of QRXZF by exploring its potential mechanism between gut microbiota and downstream inflammatory pathways mediated by gut-derived lipopolysaccharide (LPS) in the kidney. High-fat diet (HFD) and streptozotocin injection-induced DKD mice model was established to assess the QRXZF effect in vivo. Mice treated with QRXZF for 8 weeks had significantly lower levels of urinary albumin, serum cholesterol and triglycerides. The renal injuries observed through histological analysis were attenuated as well. Also, mice in the QRXZF group had higher levels of Zonula occludens protein-1 (ZO-1) expression, lower levels of serum fluorescein-isothiocyanate (FITC)-dextran and less-damaged colonic mucosa as compared to the DKD group, implying the benefit role for the gut barrier integrity. QRXZF treatment also reversed gut dysbiosis and reduced levels of gut-derived LPS. Notably, the expression of toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB), which are important inflammation pathways in DKD, were suppressed in the QRXZF groups. In conclusion, our results indicated that the reno-protective effects of QRXZF was probably associated with modulating gut microbiota and inhibiting inflammatory responses in the kidney.

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S-Nitrosylation of RhoGAP Myosin9A Is Altered in Advanced Diabetic Kidney Disease

Frontiers in Medicine ◽

10.3389/fmed.2021.679518 ◽

2021 ◽

Vol 8 ◽

Author(s):

Qi Li ◽

Delma Veron ◽

Alda Tufro

Keyword(s):

Kidney Disease ◽

High Glucose ◽

Diabetic Kidney Disease ◽

Diabetic Mice ◽

Post Translational Modification ◽

No Donor ◽

Diabetic Kidney ◽

Rhoa Activity

The molecular pathogenesis of diabetic kidney disease progression is complex and remains unresolved. Rho-GAP MYO9A was recently identified as a novel podocyte protein and a candidate gene for monogenic FSGS. Myo9A involvement in diabetic kidney disease has been suggested. Here, we examined the effect of diabetic milieu on Myo9A expression in vivo and in vitro. We determined that Myo9A undergoes S-nitrosylation, a post-translational modification dependent on nitric oxide (NO) availability. Diabetic mice with nodular glomerulosclerosis and severe proteinuria associated with doxycycline-induced, podocyte-specific VEGF164 gain-of-function showed markedly decreased glomerular Myo9A expression and S-nitrosylation, as compared to uninduced diabetic mice. Immortalized mouse podocytes exposed to high glucose revealed decreased Myo9A expression, assessed by qPCR, immunoblot and immunocytochemistry, and reduced Myo9A S-nitrosylation (SNO-Myo9A), assessed by proximity link assay and biotin switch test, functionally resulting in abnormal podocyte migration. These defects were abrogated by exposure to a NO donor and were not due to hyperosmolarity. Our data demonstrate that high-glucose induced decrease of both Myo9A expression and SNO-Myo9A is regulated by NO availability. We detected S-nitrosylation of Myo9A interacting proteins RhoA and actin, which was also altered by high glucose and NO dependent. RhoA activity inversely related to SNO-RhoA. Collectively, data suggest that dysregulation of SNO-Myo9A, SNO-RhoA and SNO-actin may contribute to the pathogenesis of advanced diabetic kidney disease and may be amenable to therapeutic targeting.

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Sitagliptin ameliorates ER stress in diabetic kidney disease through upregulation of SIRT1

Diabetic Nephropathy ◽

10.2478/dine-2021-0007 ◽

2021 ◽

Vol 1 (1) ◽

pp. 33-41

Author(s):

Qunzi Zhang ◽

Junjie Jia ◽

Li He ◽

Ying Fan ◽

Niansong Wang

Keyword(s):

Kidney Disease ◽

Er Stress ◽

Diabetic Kidney Disease ◽

Diabetic Kidney ◽

Dipeptidyl Peptidase 4 ◽

Beneficial Effects ◽

Er Homeostasis

Abstract Objectives Endoplasmic reticulum (ER) stress plays a significant role in the progression of diabetic kidney disease (DKD), and dipeptidyl peptidase-4 (DPP4) inhibitors are widely used antihyperglycemic agents, exerting renal beneficial effects in DKD. Here, we investigated the role of DPP4 inhibitor Sitagliptin (Sita) in ER homeostasis in the kidneys of diabetic DBA2/J (D2) mice and in albumin-stimulated HK-2 cells. Methods and Results ER stress was observed both in vivo and in vitro, as reflected by notably increased glucose-regulated protein of 78 kDa (GRP78), CHOP, high phosphorylation of PERK (p-PERK), and cleaved caspase3 (c-CASP3), whereas Sita effectively attenuated these disorders. Meanwhile, Sita increased the expression of SIRT1 both in vivo and in vitro. To further validate the potential effects of SIRT1 in regulating ER stress, we regulated SIRT1 by siRNA and overexpressed plasmids in albumin-overloaded HK-2 cells. Elevated SIRT1 alleviated albumin-induced ER stress, while decreased SIRT1 further aggravated ER stress in albumin-treated HK-2 cells. Conclusion The results suggest that a novel mechanism links the DPP4 enzyme to ER stress during tubular injury in DKD and highlight that SIRT1 may be a potential target for managing DKD.

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