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Ghosh Roy S, Li Z, Guo Z, Long KT, Rehrl S, Tian X, Dong K, Besse W. Dnajb11-Kidney Disease Develops from Reduced Polycystin-1 Dosage but not Unfolded Protein Response in Mice. J Am Soc Nephrol 2023; 34:1521-1534. [PMID: 37332102 PMCID: PMC10482070 DOI: 10.1681/asn.0000000000000164] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023] Open
Abstract
SIGNIFICANCE STATEMENT Heterozygous DNAJB11 mutation carriers manifest with small cystic kidneys and renal failure in adulthood. Recessive cases with prenatal cystic kidney dysplasia were recently described. Our in vitro and mouse model studies investigate the proposed disease mechanism as an overlap of autosomal-dominant polycystic kidney disease and autosomal-dominant tubulointerstitial kidney disease pathogenesis. We find that DNAJB11 loss impairs cleavage and maturation of the autosomal-dominant polycystic kidney disease protein polycystin-1 (PC1) and results in dosage-dependent cyst formation in mice. We find that Dnajb11 loss does not activate the unfolded protein response, drawing a fundamental contrast with the pathogenesis of autosomal-dominant tubulointerstitial kidney disease. We instead propose that fibrosis in DNAJB11 -kidney disease may represent an exaggerated response to polycystin-dependent cysts. BACKGROUND Patients with heterozygous inactivating mutations in DNAJB11 manifest with cystic but not enlarged kidneys and renal failure in adulthood. Pathogenesis is proposed to resemble an overlap of autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-dominant tubulointerstitial kidney disease (ADTKD), but this phenotype has never been modeled in vivo . DNAJB11 encodes an Hsp40 cochaperone in the endoplasmic reticulum: the site of maturation of the ADPKD polycystin-1 (PC1) protein and of unfolded protein response (UPR) activation in ADTKD. We hypothesized that investigation of DNAJB11 would shed light on mechanisms for both diseases. METHODS We used germline and conditional alleles to model Dnajb11 -kidney disease in mice. In complementary experiments, we generated two novel Dnajb11-/- cell lines that allow assessment of PC1 C-terminal fragment and its ratio to the immature full-length protein. RESULTS Dnajb11 loss results in a profound defect in PC1 cleavage but with no effect on other cystoproteins assayed. Dnajb11-/- mice are live-born at below the expected Mendelian ratio and die at a weaning age with cystic kidneys. Conditional loss of Dnajb11 in renal tubular epithelium results in PC1 dosage-dependent kidney cysts, thus defining a shared mechanism with ADPKD. Dnajb11 mouse models show no evidence of UPR activation or cyst-independent fibrosis, which is a fundamental distinction from typical ADTKD pathogenesis. CONCLUSIONS DNAJB11 -kidney disease is on the spectrum of ADPKD phenotypes with a PC1-dependent pathomechanism. The absence of UPR across multiple models suggests that alternative mechanisms, which may be cyst-dependent, explain the renal failure in the absence of kidney enlargement.
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Affiliation(s)
- Sounak Ghosh Roy
- Section of Nephrology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
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Sieben CJ, Harris PC. Experimental Models of Polycystic Kidney Disease: Applications and Therapeutic Testing. KIDNEY360 2023; 4:1155-1173. [PMID: 37418622 PMCID: PMC10476690 DOI: 10.34067/kid.0000000000000209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/29/2023] [Indexed: 07/09/2023]
Abstract
Polycystic kidney diseases (PKDs) are genetic disorders characterized by the formation and expansion of numerous fluid-filled renal cysts, damaging normal parenchyma and often leading to kidney failure. Although PKDs comprise a broad range of different diseases, with substantial genetic and phenotypic heterogeneity, an association with primary cilia represents a common theme. Great strides have been made in the identification of causative genes, furthering our understanding of the genetic complexity and disease mechanisms, but only one therapy so far has shown success in clinical trials and advanced to US Food and Drug Administration approval. A key step in understanding disease pathogenesis and testing potential therapeutics is developing orthologous experimental models that accurately recapitulate the human phenotype. This has been particularly important for PKDs because cellular models have been of limited value; however, the advent of organoid usage has expanded capabilities in this area but does not negate the need for whole-organism models where renal function can be assessed. Animal model generation is further complicated in the most common disease type, autosomal dominant PKD, by homozygous lethality and a very limited cystic phenotype in heterozygotes while for autosomal recessive PKD, mouse models have a delayed and modest kidney disease, in contrast to humans. However, for autosomal dominant PKD, the use of conditional/inducible and dosage models have resulted in some of the best disease models in nephrology. These have been used to help understand pathogenesis, to facilitate genetic interaction studies, and to perform preclinical testing. Whereas for autosomal recessive PKD, using alternative species and digenic models has partially overcome these deficiencies. Here, we review the experimental models that are currently available and most valuable for therapeutic testing in PKD, their applications, success in preclinical trials, advantages and limitations, and where further improvements are needed.
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Affiliation(s)
- Cynthia J Sieben
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
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Edwards ME, Periyanan S, Anaam D, Gregory AV, Kline TL. Automated total kidney volume measurements in pre-clinical magnetic resonance imaging for resourcing imaging data, annotations, and source code. Kidney Int 2020; 99:763-766. [PMID: 32828755 DOI: 10.1016/j.kint.2020.07.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/10/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
The objective of this study was to validate a fully automated total kidney volume measurement method for pre-clinical rodent trials that is fast, accurate, reproducible, and to provide these resources to the research community. Rodent studies that involve imaging are crucial for monitoring treatment efficacy in diseases such as polycystic kidney disease. Previous studies utilize manual or semi-automated segmentations, which are time consuming and potentially biased. To develop our automated system, a total of 150 axial magnetic resonance images (MRI) from a variety of mouse models were manually segmented and used to train/validate an automated algorithm. To test the longitudinal application of the model, four mutant and four wild-type mice were imaged sequentially over three to twelve weeks via MRI. Segmentations of the kidneys (excluding the renal pelvis) were generated by the automated method and two different readers, with one reader repeating the measurements. Similarity metrics and longitudinal analysis were calculated to assess the performance of the automated compared to the manual methods. The automated approach required no user input, besides a final visual quality control step. Similarity metrics of the automated method versus the manual segmentations were on par with inter- and intra-reader comparisons. Thus, our fully automated approach described here can be safely used in longitudinal, pre-clinical trials that involve the segmentation of rodent kidneys in T2-weighted MRIs.
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Affiliation(s)
- Marie E Edwards
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Sigapriya Periyanan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Deema Anaam
- Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Adriana V Gregory
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Timothy L Kline
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
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Zhang M, Srichai MB, Zhao M, Chen J, Davis LS, Wu G, Breyer MD, Hao CM. Nonselective Cyclooxygenase Inhibition Retards Cyst Progression in a Murine Model of Autosomal Dominant Polycystic Kidney Disease. Int J Med Sci 2019; 16:180-188. [PMID: 30662341 PMCID: PMC6332488 DOI: 10.7150/ijms.27719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 12/07/2018] [Indexed: 12/31/2022] Open
Abstract
Aim: Autosomal dominant polycystic kidney disease is one of the most common genetic renal diseases. Cyclooxygenase plays an important role in epithelial cell proliferation and may contribute to the mechanisms underlying cyst formation. The aim of the present study was to evaluate the role of cyclooxygenase inhibition in the cyst progression in polycystic kidney disease. Method: Pkd2WS25/- mice, a murine model which harbors a compound cis-heterozygous mutation of the Pkd2 gene were used. Cyclooxygenase expression was assessed in both human and murine kidney specimens. Pkd2WS25/- mice were treated with Sulindac (a nonselective cyclooxygenase inhibitor) or vehicle for 8 months starting at three weeks age, and then renal cyst burden was assessed by kidney weight and volume. Results: Cyclooxygenase-2 expression was up-regulated compared to control kidneys as shown by RNase protection in human polycystic kidneys and immunoblot in mouse Pkd2WS25/- kidneys. Cyclooxygenase-2 expression was up-regulated in the renal interstitium as well as focal areas of the cystic epithelium (p<0.05). Basal Cyclooxygenase-1 levels were unchanged in both immunohistochemistry and real-time PCR. Administration of Sulindac to Pkd2WS25/- mice and to control mice for 8 months resulted in reduced kidney weights and volume in cystic mice. Renal function and electrolytes were not significantly different between groups. Conclusion: Thus treatment of a murine model of polycystic kidney disease with Sulindac results in decreased kidney cyst burden. These findings provide additional implications for the use of Cyclooxygenase inhibition as treatment to slow the progression of cyst burden in patients with polycystic kidney disease.
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Affiliation(s)
- Min Zhang
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China
| | - Manakan B Srichai
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN.,VA Medical Center, Nashville, TN
| | - Min Zhao
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN
| | - Jian Chen
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN
| | - Linda S Davis
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN
| | - Guanqing Wu
- Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN.,Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Matthew D Breyer
- Biotechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46225, USA
| | - Chuan-Ming Hao
- Division of Nephrology, Huashan Hospital, Fudan University, Shanghai, China.,Department of Medicine, Division of Nephrology, Vanderbilt University, Nashville, TN.,VA Medical Center, Nashville, TN
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Steinert EM, Schenkel JM, Fraser KA, Beura LK, Manlove LS, Igyártó BZ, Southern PJ, Masopust D. Quantifying Memory CD8 T Cells Reveals Regionalization of Immunosurveillance. Cell 2016; 161:737-49. [PMID: 25957682 DOI: 10.1016/j.cell.2015.03.031] [Citation(s) in RCA: 504] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 12/09/2014] [Accepted: 02/23/2015] [Indexed: 12/11/2022]
Abstract
Memory CD8 T cells protect against intracellular pathogens by scanning host cell surfaces; thus, infection detection rates depend on memory cell number and distribution. Population analyses rely on cell isolation from whole organs, and interpretation is predicated on presumptions of near complete cell recovery. Paradigmatically, memory is parsed into central, effector, and resident subsets, ostensibly defined by immunosurveillance patterns but in practice identified by phenotypic markers. Because isolation methods ultimately inform models of memory T cell differentiation, protection, and vaccine translation, we tested their validity via parabiosis and quantitative immunofluorescence microscopy of a mouse memory CD8 T cell population. We report three major findings: lymphocyte isolation fails to recover most cells and biases against certain subsets, residents greatly outnumber recirculating cells within non-lymphoid tissues, and memory subset homing to inflammation does not conform to previously hypothesized migration patterns. These results indicate that most host cells are surveyed for reinfection by segregated residents rather than by recirculating cells that migrate throughout the blood and body.
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Affiliation(s)
- Elizabeth M Steinert
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jason M Schenkel
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kathryn A Fraser
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Lalit K Beura
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Luke S Manlove
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Botond Z Igyártó
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA; Department of Dermatology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Peter J Southern
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA
| | - David Masopust
- Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Immunology, University of Minnesota, Minneapolis, MN 55455, USA.
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Ravichandran K, Ozkok A, Wang Q, Mullick AE, Edelstein CL. Antisense-mediated angiotensinogen inhibition slows polycystic kidney disease in mice with a targeted mutation in Pkd2. Am J Physiol Renal Physiol 2014; 308:F349-57. [PMID: 25537744 DOI: 10.1152/ajprenal.00478.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Renal cyst enlargement is associated with the activation of both the circulating and intrarenal renin-angiotensin systems. Angiotensinogen (AGT) is the substrate for renin. The aim of the present study was to determine the effect of AGT inhibition on renal cyst enlargement. An AGT antisense oligonucleotide (ASO) that selectively inhibits AGT mRNA was injected once weekly in PKD2WS25 mice [an orthologous model of human autosmal dominant polycystic kidney disease (PKD) involving mutation of the Pkd2 gene] from 4 to 16 wk of age. The AGT ASO resulted in a 40% decrease in AGT RNA in the kidney, a 60% decrease in AGT RNA in the liver, and a significant decrease in AGT protein in the kidney and serum. The AGT ASO resulted in a significant decrease in kidney size, cyst volume density, and blood urea nitrogen. The AGT ASO resulted in a significant decrease in transforming growth factor-β and interstitial fibrosis in the kidney. Mice treated with the AGT ASO had a significant decrease in proinflammatory cytokines [chemokine (C-X-C motif) ligand (CXCL)1 and IL-12] in the kidney. Cluster of differentiation (CD)36 is a scavenger receptor found on tubular cells that can activate the renin-angiotensin system. Administration of a CD36 ASO had no effect on PKD and kidney function, suggesting that the effect of the AGT ASO is independent of CD36. In summary, AGT inhibition resulted in significant decreases in kidney size and cyst volume and an improvement in kidney function in PKD mice. The AGT ASO resulted in a decrease in transforming growth factor-β, interstitial fibrosis, and the proinflammatory cytokines CXCL1 and IL-12 in the kidney.
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Affiliation(s)
- Kameswaran Ravichandran
- Division of Renal Diseases and Hypertension, University of Colorado at Denver, Aurora, Colorado; and
| | - Abdullah Ozkok
- Division of Renal Diseases and Hypertension, University of Colorado at Denver, Aurora, Colorado; and
| | - Qian Wang
- Division of Renal Diseases and Hypertension, University of Colorado at Denver, Aurora, Colorado; and
| | | | - Charles L Edelstein
- Division of Renal Diseases and Hypertension, University of Colorado at Denver, Aurora, Colorado; and
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Ravichandran K, Zafar I, He Z, Doctor RB, Moldovan R, Mullick AE, Edelstein CL. An mTOR anti-sense oligonucleotide decreases polycystic kidney disease in mice with a targeted mutation in Pkd2. Hum Mol Genet 2014; 23:4919-31. [PMID: 24847003 DOI: 10.1093/hmg/ddu208] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening hereditary disease in the USA. In human ADPKD studies, sirolimus, a mammalian target of rapamycin complex 1 (mTORC1) inhibitor, had little therapeutic effect. While sirolimus robustly inhibits mTORC1, it has a minimal effect on mTOR complex 2 (mTORC2). Polycystic kidneys of Pkd2WS25/- mice, an orthologous model of human ADPKD caused by a mutation in the Pkd2 gene, had an early increase in pS6 (marker of mTORC1) and pAktSer(473) (marker of mTORC2). To investigate the effect of combined mTORC1 and 2 inhibition, Pkd2WS25/- mice were treated with an mTOR anti-sense oligonucleotide (ASO) that blocks mTOR expression thus inhibiting both mTORC1 and 2. The mTOR ASO resulted in a significant decrease in mTOR protein, pS6 and pAktSer(473). Pkd2WS25/- mice treated with the ASO had a normalization of kidney weights and kidney function and a marked decrease in cyst volume. The mTOR ASO resulted in a significant decrease in proliferation and apoptosis of tubular epithelial cells. To demonstrate the role of mTORC2 on cyst growth, Rictor, the functional component of mTORC2, was silenced in Madin-Darby canine kidney cell cysts grown in 3D cultures. Silencing Rictor significantly decreased cyst volume and expression of pAktSer(473). The decreased cyst size in the Rictor silenced cells was reversed by introduction of a constitutively active Akt1. In vitro, combined mTORC1 and 2 inhibition reduced cyst growth more than inhibition of mTORC1 or 2 alone. In conclusion, combined mTORC1 and 2 inhibition has therapeutic potential in ADPKD.
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Affiliation(s)
| | - Iram Zafar
- Division of Renal Diseases and Hypertension
| | - Zhibin He
- Division of Renal Diseases and Hypertension
| | | | - Radu Moldovan
- Advanced Light Microscopy Core Facility, University of Colorado at Denver, Aurora, CO, USA
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Aihara M, Fujiki H, Mizuguchi H, Hattori K, Ohmoto K, Ishikawa M, Nagano K, Yamamura Y. Tolvaptan delays the onset of end-stage renal disease in a polycystic kidney disease model by suppressing increases in kidney volume and renal injury. J Pharmacol Exp Ther 2014; 349:258-67. [PMID: 24570071 DOI: 10.1124/jpet.114.213256] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Tolvaptan, a selective vasopressin V2 receptor antagonist, slows the increase in total kidney volume and the decline in kidney function in patients with the results of the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Outcome (TEMPO) 3:4 trial. However, it was unclear which dose of tolvaptan was optimal or whether tolvaptan was able to delay progression to end-stage renal disease (ESRD). Here we examined the relationship with aquaresis and the inhibitory effect on cyst development in short-term treatment and mortality as an index of ESRD in long-term treatment with tolvaptan using DBA/2FG-pcy mice, an animal model of nephronophthisis. With short-term treatment from 5 to 15 weeks of age, tolvaptan (0.01-0.3% via diet) dose-dependently enhanced aquaresis, prevented increases in kidney weight and cyst volume, and was associated with significant reductions in kidney cAMP levels and extracellular signal-regulated kinase activity. Maximal effects of tolvaptan on aquaresis and the prevention of development of polycystic kidney disease (PKD) were obtained at 0.1%. Interestingly, tolvaptan also dose-dependently reduced urinary neutrophil gelatinase-associated lipocalin levels in correlation with the kidney volume. With long-term treatment from 5 to 29 weeks of age, tolvaptan significantly attenuated the increase in kidney volume by up to 50% and reduced urinary albumin excretion. Furthermore, tolvaptan significantly reduced the mortality rate to 20%, compared with 60% in the control group. These data indicate that tolvaptan may delay the onset of ESRD in PKD by suppressing the increases in kidney volume and renal injury, providing a promising treatment for PKD.
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Affiliation(s)
- Miki Aihara
- First Institute of New Drug Discovery (M.A., H.F., H.M., K.H., K.O., K.N.) and Laboratory of Bioenergetics Research, Tokushima Research Institute (M.I.), Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan; and Global Pharmaceutical Business, Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan (Y.Y.)
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Thurman JM, Serkova NJ. Nanosized contrast agents to noninvasively detect kidney inflammation by magnetic resonance imaging. Adv Chronic Kidney Dis 2013; 20:488-99. [PMID: 24206601 DOI: 10.1053/j.ackd.2013.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 06/02/2013] [Accepted: 06/03/2013] [Indexed: 12/15/2022]
Abstract
Several molecular imaging methods have been developed that use nanosized contrast agents to detect markers of inflammation within tissues. Kidney inflammation contributes to disease progression in a wide range of autoimmune and inflammatory diseases, and a biopsy is currently the only method of definitively diagnosing active kidney inflammation. However, the development of new molecular imaging methods that use contrast agents capable of detecting particular immune cells or protein biomarkers will allow clinicians to evaluate inflammation throughout the kidneys and to assess a patient's response to immunomodulatory drugs. These imaging tools will improve our ability to validate new therapies and to optimize the treatment of individual patients with existing therapies. This review describes the clinical need for new methods of monitoring kidney inflammation and recent advances in the development of nanosized contrast agents for the detection of inflammatory markers of kidney disease.
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Belibi F, Zafar I, Ravichandran K, Segvic AB, Jani A, Ljubanovic DG, Edelstein CL. Hypoxia-inducible factor-1α (HIF-1α) and autophagy in polycystic kidney disease (PKD). Am J Physiol Renal Physiol 2011; 300:F1235-43. [PMID: 21270095 PMCID: PMC3094047 DOI: 10.1152/ajprenal.00348.2010] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 01/24/2011] [Indexed: 01/05/2023] Open
Abstract
Cyst expansion in polycystic kidney disease (PKD) results in localized hypoxia in the kidney that may activate hypoxia-inducible factor-1α (HIF-1α). HIF-1α and autophagy, a form of programmed cell repair, are induced by hypoxia. The purposes were to determine HIF-1α expression and autophagy in rat and mouse models of PKD. HIF-1α was detected by electrochemiluminescence. Autophagy was visualized by electron microscopy (EM). LC3 and beclin-1, markers of autophagy, were detected by immunoblotting. Eight-week-old male heterozygous (Cy/+) and 4-wk-old homozygous (Cy/Cy) Han:SPRD rats, 4-wk-old cpk mice, and 112-day-old Pkd2WS25/- mice with a mutation in the Pkd2 gene were studied. HIF-1α was significantly increased in massive Cy/Cy and cpk kidneys and not smaller Cy/+ and Pkd2WS25/- kidneys. On EM, features of autophagy were seen in wild-type (+/+), Cy/+, and cpk kidneys: autophagosomes, mitophagy, and autolysosomes. Specifically, autophagosomes were found on EM in the tubular cells lining the cysts in cpk mice. The increase in LC3-II, a marker of autophagosome production and beclin, a regulator of autophagy, in Cy/Cy and cpk kidneys, followed the same pattern of increase as HIF-1α. To determine the role of HIF-1α in cyst formation and/or growth, Cy/+ rats, Cy/Cy rats, and cpk mice were treated with the HIF-1α inhibitor 2-methoxyestradiol (2ME2). 2ME2 had no significant effect on kidney volume or cyst volume density. In summary, HIF-1α is highly expressed in the late stages of PKD and is associated with an increase in LC3-II and beclin-1. The first demonstration of autophagosomes in PKD kidneys is reported. Inhibition of HIF-1α did not have a therapeutic effect.
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Affiliation(s)
- Franck Belibi
- Division of Renal Diseases and Hypertension, University of Colorado at Denver and Health Sciences Center, Aurora, 80262, USA
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Bichet DG. Kidney and liver cysts in autosomal dominant polycystic kidney disease. Nephrol Dial Transplant 2010; 25:3472-3. [PMID: 20846938 DOI: 10.1093/ndt/gfq567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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