Emerging roles for miRNAs in the development, diagnosis, and treatment of diabetic nephropathy

Current Diabetes Reports

Volumn 13, Issue 4, 2013, Pages 582-591

  Distefano, Johanna K ^a   Taila, Matthew ^a   Alvarez, M Lucrecia ^a  

^a TRANSLATIONAL GENOMICS RESEARCH INSTITUTE   (United States)

Author keywords

Biomarkers; Chronic kidney disease; Diabetic nephropathy; End stage renal disease; Epigenetics; Locked nucleic acid (LNA); miR 1207 5p; miR 192; miR 21; miR 29; MiRNAs; Renal fibrosis; Transforming growth factor ; Urinary exosomes; Urine

Indexed keywords

DOUBLE STRANDED RNA; HEPARIN BINDING EPIDERMAL GROWTH FACTOR; MICRORNA; MICRORNA 1207; MICRORNA 192; MICRORNA 195; MICRORNA 21; MICRORNA 29A; MICRORNA 29B; MICRORNA 29C; MICRORNA 451; MITOGEN ACTIVATED PROTEIN KINASE P38; SHORT HAIRPIN RNA; UNCLASSIFIED DRUG;

3' UNTRANSLATED REGION; ALBUMINURIA; ALLELE; ARTICLE; ASTHMA; BLOOD LEVEL; BREAST MILK; CARDIOVASCULAR DISEASE; CELL PROLIFERATION; CEREBROSPINAL FLUID ANALYSIS; CHRONIC KIDNEY FAILURE; DEMENTIA; DIABETIC NEPHROPATHY; DIAGNOSTIC VALUE; DISEASE ACTIVITY; DISEASE COURSE; DISEASE PREDISPOSITION; ENZYME ACTIVATION; EPIGENETICS; GENE; GENE EXPRESSION; GENE EXPRESSION REGULATION; GENE FUNCTION; GENE VECTOR; GENETIC ASSOCIATION; GENETIC RISK; GENETIC VARIABILITY; GLOMERULUS FILTRATION RATE; HEART MUSCLE FIBROSIS; HUMAN; IN VITRO STUDY; IN VIVO STUDY; MALIGNANT NEOPLASTIC DISEASE; MESANGIUM CELL; MOLECULAR MECHANICS; NONHUMAN; PATHOGENESIS; PVT1 GENE; RENIN ANGIOTENSIN ALDOSTERONE SYSTEM; RISK FACTOR; RNA ANALYSIS; SINGLE NUCLEOTIDE POLYMORPHISM; URINE LEVEL;

ANIMALS; BIOLOGICAL MARKERS; DIABETIC NEPHROPATHIES; DISEASE PROGRESSION; GENETIC VARIATION; HUMANS; MICRORNAS;

EID: 84880134824     PISSN: 15344827     EISSN: 15390829     Source Type: Journal    
DOI: 10.1007/s11892-013-0386-8     Document Type: Article

References (98)

1. Whiting DR, Guariguata L, Weil C, Shaw J. IDF diabetes atlas: global estimates of the prevalence of diabetes for 2011 and 2030. Diabetes Res Clin Pract. 2011;94:311-21.
2. Jones CA, Krolewski A, Rogus J, Xue JL, Collins A, Warram JH. Epidemic of end-stage renal disease in people with diabetes in the United States population: do we know the cause? Kidney Int. 2005;67:1684-91.
3. Gray SP, Cooper ME. Diabetic nephropathy in 2010: alleviating the burden of diabetic nephropathy. Nat Rev Nephrol. 2011;7:71-3.
4. Hayden PS, Iyengar SK, Schelling JR, Sedor JR. Kidney disease, genotype and the pathogenesis of vasculopathy. Curr Opin Nephrol Hypertens. 2003;12:71-8.
5. The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329:977-86.
6. Gaede P, Vedel P, Parving HH, Pedersen O. Intensified multifactorial intervention in patients with type 2 diabetes mellitus and microalbuminuria: the Steno type 2 randomized study. Lancet. 1999;353:617-22.
7. Lewis EJ, Hunsicker LG, Bain RP, Rohde RD. The effect of angiotensin-converting-enzyme inhibition on diabetic nephropathy. The Collaborative Study Group. N Engl J Med. 1993;329:1456-62.
8. Nelson RG, Knowler WC, Pettitt DJ, Hanson RL, Bennett PH. Incidence and determinants of elevated urinary albumin excretion in Pima Indians with NIDDM. Diabetes Care. 1995;18:182-7.
9. Pettitt DJ, Saad MF, Bennett PH, Nelson RG, Knowler WC. Familial predisposition to renal disease in two generations of Pima Indians with type 2 (non-insulin-dependent) diabetes mellitus. Diabetologia. 1990;33:438-43.
10. Quinn M, Angelico MC, Warram JH, Krolewski AS. Familial factors determine the development of diabetic nephropathy in patients with IDDM. Diabetologia. 1996;39:940-5.
11. Ravid M, Brosh D, Ravid-Safran D, Levy Z, Rachmani R. Main risk factors for nephropathy in type 2 diabetes mellitus are plasma cholesterol levels, mean blood pressure, and hyperglycemia. Arch Intern Med. 1998;158:998-1004.
12. Seaquist ER, Goetz FC, Rich S, Barbosa J. Familial clustering of diabetic kidney disease. Evidence for genetic susceptibility to diabetic nephropathy. N Engl J Med. 1989;320:1161-5.
13. Craig DW, Millis MP, DiStefano JK. Genome-wide SNP genotyping study using pooled DNA to identify candidate markers mediating susceptibility to end-stage renal disease attributed to type 1 diabetes. Diabet Med. 2009;26:1090-8.
14. Hanson RL, Craig DW, Millis MP, Yeatts KA, Kobes S, Pearson JV, et al. Identification of PVT1 as a candidate gene for end-stage renal disease in Type 2 Diabetes using a pooling-based genome-wide single nucleotide polymorphism association study. Diabetes. 2007;56:975-83.
15. McDonough CW, Palmer ND, Hicks PJ, Roh BH, An SS, Cooke JN, et al. A genome-wide association study for diabetic nephropathy genes in African Americans. Kidney Int. 2011;79:563-72.
16. McKnight AJ, Maxwell AP, Sawcer S, Compston A, Setakis E, Patterson CC, et al. A genome-wide DNA microsatellite association screen to identify chromosomal regions harboring candidate genes in diabetic nephropathy. J Am Soc Nephrol. 2006;17:831-6.
17. Pezzolesi MG, Poznik GD, Mychaleckyj JC, Paterson AD, Barati MT, Klein JB, et al. Genome-wide association scan for diabetic nephropathy susceptibility genes in type 1 diabetes. Diabetes. 2009;58:1403-10.
18. Sandholm N, Salem RM, McKnight AJ, Brennan EP, Forsblom C, Isakova T, et al. New susceptibility loci associated with kidney disease in type 1 diabetes. PLoS Genet. 2012;8:e1002921.
19. Fabian MR, Cieplak MK, Frank F, Morita M, Green J, Srikumar T, et al. miRNA-mediated deadenylation is orchestrated by GW182 through two conserved motifs that interact with CCR4-NOT. Nat Struct Mol Biol. 2011;18:1211-7.
20. Huntzinger E, Izaurralde E. Gene silencing by microRNAs: contributions of translational repression and mRNA decay. Nat Rev Genet. 2011;12:99-110.
21. Natarajan R, Putta S, Kato M. MicroRNAs and diabetic complications. J Cardiovasc Transl Res. 2012;5:413-22.
22. Tang X, Tang G, Ozcan S. Role of microRNAs in diabetes. Biochim Biophys Acta. 2008;1779:697-701.
23. Sun Y, Koo S, White N, Peralta E, Esau C, Dean NM, et al. Development of a micro-array to detect human and mouse microRNAs and characterization of expression in human organs. Nucleic Acids Res. 2004;32:e188.
24. Kato M, Arce L, Wang M, Putta S, Lanting L, Natarajan R. A microRNA circuit mediates transforming growth factor-β1 autoregulation in renal glomerular mesangial cells. Kidney Int. 2011;80:358-68.
25. Kato M, Putta S, Wang M, Yuan H, Lanting L, Nair I, et al. TGF-β activates Akt kinase through a microRNA-dependent amplifying circuit targeting PTEN. Nat Cell Biol. 2009;11:881-9.
26. Kato M, Wang L, Putta S, Wang M, Yuan H, Sun G, et al. Post-transcriptional up-regulation of Tsc-22 by Ybx1, a target of miR-216a, mediates TGF-β-induced collagen expression in kidney cells. J Biol Chem. 2010;285:34004-15.
27. Kato M, Zhang J, Wang M, Lanting L, Yuan H, Rossi JJ, et al. MicroRNA-192 in diabetic kidney glomeruli and its function in TGF-β-induced collagen expression via inhibition of E-box repressors. Proc Natl Acad Sci U S A. 2007;104:3432-7.
28. Long J, Wang Y, Wang W, Chang BH, Danesh FR. MicroRNA-29c is a signature microRNA under high glucose conditions that targets Sprouty homolog 1, and its in vivo knockdown prevents progression of diabetic nephropathy. J Biol Chem. 2011;286:11837-48.
29. Alvarez ML, DiStefano JK. The role of non-coding RNAs in diabetic nephropathy: potential applications as biomarkers for disease development and progression. Diabetes Res Clin Pract. 2013;99:1-11.
30. Kato M, Park JT, Natarajan R. MicroRNAs and the glomerulus. Exp Cell Res. 2012;318:993-1000.
31. • Zhang Z, Luo X, Ding S, Chen J, Chen T, Chen X, et al. MicroRNA-451 regulates p38 MAPK signaling by targeting of Ywhaz and suppresses the mesangial hypertrophy in early diabetic nephropathy. FEBS Lett. 2012;586:20-6. This article provides important evidence for the role of a new miRNA player in early diabetic nephropathy.
32. Cuenda A, Rousseau S. p38 MAP-kinases pathway regulation, function and role in human diseases. Biochim Biophys Acta. 2007;1773:1358-75.
33. Zarubin T, Han J. Activation and signaling of the p38 MAP kinase pathway. Cell Res. 2005;15:11-8.
34. Kang SW, Adler SG, Lapage J, Natarajan R. p38 MAPK and MAPK kinase 3/6 mRNA and activities are increased in early diabetic glomeruli. Kidney Int. 2001;60:543-52.
35. Chen YQ, Wang XX, Yao XM, Zhang DL, Yang XF, Tian SF, et al. MicroRNA-195 promotes apoptosis in mouse podocytes via enhanced caspase activity driven by BCL2 insufficiency. Am J Nephrol. 2011;34:549-59.
36. Stitt-Cavanagh E, MacLeod L, Kennedy C. The podocyte in diabetic kidney disease. SciWorld J. 2009;9:1127-39.
37. Chen YQ, Wang XX, Yao XM, Zhang DL, Yang XF, Tian SF, et al. Abated microRNA-195 expression protected mesangial cells from apoptosis in early diabetic renal injury in mice. J Nephrol. 2012;25:566-76.
38. Wolf G. Molecular mechanisms of diabetic mesangial cell hypertrophy: a proliferation of novel factors. J Am Soc Nephrol. 2002;13:2611-3.
39. •• Putta S, Lanting L, Sun G, Lawson G, Kato M, Natarajan R. Inhibiting microRNA-192 ameliorates renal fibrosis in diabetic nephropathy. J Am Soc Nephrol. 2012;23:458-69. This article demonstrates that LNA anti-miR-192 not only diminished kidney fibrosis but also decreased proteinuria in diabetic mice.
40. Wang B, Komers R, Carew R, Winbanks CE, Xu B, Herman-Edelstein M, et al. Suppression of microRNA-29 expression by TGF-β1 promotes collagen expression and renal fibrosis. J Am Soc Nephrol. 2012;23:252-65.
41. Du B, Ma LM, Huang MB, Zhou H, Huang HL, Shao P, et al. High glucose down-regulates miR-29a to increase collagen IV production in HK-2 cells. FEBS Lett. 2010;584:811-6.
42. Bauersachs J. miR-21: a central regulator of fibrosis not only in the broken heart. Cardiovasc Res. 2012;96:227-9.
43. Liu G, Friggeri A, Yang Y, Milosevic J, Ding Q, Thannickal VJ, et al. miR-21 mediates fibrogenic activation of pulmonary fibroblasts and lung fibrosis. J Exp Med. 2010;207:1589-97.
44. • Dey N, Das F, Mariappan MM, Mandal CC, Ghosh-Choudhury N, Kasinath BS, et al. MicroRNA-21 orchestrates high glucose-induced signals to TOR complex 1, resulting in renal cell pathology in diabetes. J Biol Chem. 2011;286:25586-603. This article demonstrates that miR-21 increases in kidney cells cultured in the presence of TGF-β1 or high glucose, and downregulates PTEN, which activates AKT kinase and PI3K inducing mesangial hypertrophy and tubulointerstitial fibrosis.
45. Zarjou A, Yang S, Abraham E, Agarwal A, Liu G. Identification of a microRNA signature in renal fibrosis: role of miR-21. Am J Physiol Renal Physiol. 2011;301:F793-801.
46. •• Chau BN, Xin C, Hartner J, Ren S, Castano AP, Linn G, et al. MicroRNA-21 promotes fibrosis of the kidney by silencing metabolic pathways. Sci Transl Med. 2012;4:121. miR-21 knockout mice showed no overt abnormalities and suffered less interstitial fibrosis in response to kidney injury.
47. Borel C, Antonarakis SE. Functional genetic variation of human miRNAs and phenotypic consequences. Mamm Genome. 2008;19:503-9.
48. Papagregoriou G, Erguler K, Dweep H, Voskarides K, Koupepidou P, Athanasiou Y, et al. A miR-1207-5p binding site polymorphism abolishes regulation of HBEGF and is associated with disease severity in CFHR5 nephropathy. PLoS One. 2012;7:e31021.
49. Sun G, Yan J, Noltner K, Feng J, Li H, Sarkis DA, et al. SNPs in human miRNA genes affect biogenesis and function. RNA. 2009;15:1640-51.
50. Xu J, Hu Z, Xu Z, Gu H, Yi L, Cao H, et al. Functional variant in microRNA-196a2 contributes to the susceptibility of congenital heart disease in a Chinese population. Hum Mutat. 2009;30:1231-6.
51. Ambros V. The functions of animal microRNAs. Nature. 2004;431:350-5.
52. Saunders MA, Liang H, Li WH. Human polymorphism at microRNAs and microRNA target sites. Proc Natl Acad Sci U S A. 2007;104:3300-5.
53. Martin MM, Buckenberger JA, Jiang J, Malana GE, Nuovo GJ, Chotani M, et al. The human angiotensin II type 1 receptor +1166 A/C polymorphism attenuates microrna-155 binding. J Biol Chem. 2007;282:24262-9.
54. Tan Z, Randall G, Fan J, Camoretti-Mercado B, Brockman-Schneider R, Pan L, et al. Allele-specific targeting of microRNAs to HLA-G and risk of asthma. Am J Hum Genet. 2007;81:829-34.
55. Rademakers R, Eriksen JL, Baker M, Robinson T, Ahmed Z, Lincoln SJ, et al. Common variation in the miR-659 binding-site of GRN is a major risk factor for TDP43-positive frontotemporal dementia. Hum Mol Genet. 2008;17:3631-42.
56. Brendle A, Lei H, Brandt A, Johansson R, Enquist K, Henriksson R, et al. Polymorphisms in predicted microRNA-binding sites in integrin genes and breast cancer: ITGB4 as prognostic marker. Carcinogenesis. 2008;29:1394-9.
57. Chin LJ, Ratner E, Leng S, Zhai R, Nallur S, Babar I, et al. A SNP in a let-7 microRNA complementary site in the KRAS 3' untranslated region increases non-small cell lung cancer risk. Cancer Res. 2008;68:8535-40.
58. He H, Jazdzewski K, Li W, Liyanarachchi S, Nagy R, Volinia S, et al. The role of microRNA genes in papillary thyroid carcinoma. Proc Natl Acad Sci U S A. 2005;102:19075-80.
59. Nicoloso MS, Sun H, Spizzo R, Kim H, Wickramasinghe P, Shimizu M, et al. Single-nucleotide polymorphisms inside microRNA target sites influence tumor susceptibility. Cancer Res. 2010;70:2789-98.
60. Saetrom P, Biesinger J, Li SM, Smith D, Thomas LF, Majzoub K, et al. A risk variant in an miR-125b binding site in BMPR1B is associated with breast cancer pathogenesis. Cancer Res. 2009;69:7459-65.
61. Abelson JF, Kwan KY, O'Roak BJ, Baek DY, Stillman AA, Morgan TM, et al. Sequence variants in SLITRK1 are associated with Tourette's syndrome. Science. 2005;310:317-20.
62. Dickson DW, Baker M, Rademakers R. Common variant in GRN is a genetic risk factor for hippocampal sclerosis in the elderly. Neurodegener Dis. 2010;7:170-4.
63. Wang G, van der Walt JM, Mayhew G, Li YJ, Zuchner S, Scott WK, et al. Variation in the miRNA-433 binding site of FGF20 confers risk for Parkinson disease by overexpression of alpha-synuclein. Am J Hum Genet. 2008;82:283-9.
64. Bruno AE, Li L, Kalabus JL, Pan Y, Yu A, Hu Z. miRdSNP: a database of disease-associated SNPs and microRNA target sites on 3'UTRs of human genes. BMC Genomics. 2012;13:44.
65. Millis MP, Bowen D, Kingsley C, Watanabe RM, Wolford JK. Variants in the plasmacytoma variant translocation gene (PVT1) are associated with end-stage renal disease attributed to type 1 diabetes. Diabetes. 2007;56:3027-32.
66. Alvarez ML, DiStefano JK. Functional characterization of the plasmacytoma variant translocation 1 gene (PVT1) in diabetic nephropathy. PLoS One. 2010;6:e18671.
67. Bao L, Zhou M, Wu L, Lu L, Goldowitz D, Williams RW, et al. PolymiRTS Database: linking polymorphisms in microRNA target sites with complex traits. Nucleic Acids Res. 2007;35:D51-4.
68. Hariharan M, Scaria V, Brahmachari SK. dbSMR: a novel resource of genome-wide SNPs affecting microRNA mediated regulation. BMC Bioinforma. 2009;10:108.
69. Hiard S, Charlier C, Coppieters W, Georges M, Baurain D. Patrocles: a database of polymorphic miRNA-mediated gene regulation in vertebrates. Nucleic Acids Res. 2010;38:D640-51.
70. Blumenthal SS. Evolution of treatment for diabetic nephropathy: historical progression from RAAS inhibition and onward. Postgrad Med. 2011;123:166-79.
71. Lu J, Getz G, Miska EA, Alvarez-Saavedra E, Lamb J, Peck D, et al. MicroRNA expression profiles classify human cancers. Nature. 2005;435:834-8.
72. Bhatt K, Mi QS, Dong Z. microRNAs in kidneys: biogenesis, regulation, and pathophysiological roles. Am J Physiol Renal Physiol. 2011;300:F602-10.
73. Wang G, Kwan BC, Lai FM, Chow KM, Kam-Tao Li P, Szeto CC. Expression of microRNAs in the urinary sediment of patients with IgA nephropathy. Dis Markers. 2010;28:79-86.
74. • Wang G, Kwan BC, Lai FM, Chow KM, Li PK, Szeto CC. Urinary miR-21, miR-29, and miR-93: novel biomarkers of fibrosis. Am J Nephrol. 2012;36:412-8. This study shows correlation of specific miRNAs and renal fibrosis.
75. • Szeto CC, Ching-Ha KB, Ka-Bik L, Mac-Moune LF, Cheung-Lung CP, Gang W, et al. Micro-RNA expression in the urinary sediment of patients with chronic kidney diseases. Dis Markers. 2012;33:137-44. This study shows a correlation between rate of GFR decline and urinary levels of specific miRNAs.
76. Wang G, Kwan BC, Lai FM, Chow KM, Li PK, Szeto CC. Urinary sediment miRNA levels in adult nephrotic syndrome. Clin Chim Acta. 2013;418C:5-11.
77. Luo Y, Wang C, Chen X, Zhong T, Cai X, Chen S, et al. Increased serum and urinary micrornas in children with Idiopathic Nephrotic syndrome. Clin Chem. 2013;59:658-66.
78. •• Argyropoulos C, Wang K, McClarty S, Huang D, Bernardo J, Ellis D, et al. Urinary microRNA profiling in the nephropathy of type 1 diabetes. PLoS One. 2013;8:e54662. This study shows important preliminary evidence supporting the value of miRNAs as molecular signatures associated with distinct clinical stages of diabetic kidney disease.
79. Gilad S, Meiri E, Yogev Y, Benjamin S, Lebanony D, Yerushalmi N, et al. Serum microRNAs are promising novel biomarkers. PLoS One. 2008;3:e3148.
80. Valadi H, Ekstrom K, Bossios A, Sjostrand M, Lee JJ, Lotvall JO. Exosome-mediated transfer of mRNAs and microRNAs is a novel mechanism of genetic exchange between cells. Nat Cell Biol. 2007;9:654-9.
81. Miranda KC, Bond DT, McKee M, Skog J, Paunescu TG, Da Silva N, et al. Nucleic acids within urinary exosomes/microvesicles are potential biomarkers for renal disease. Kidney Int. 2010;78:191-9.
82. Gonzales PA, Pisitkun T, Hoffert JD, Tchapyjnikov D, Star RA, Kleta R, et al. Large-scale proteomics and phosphoproteomics of urinary exosomes. J Am Soc Nephrol. 2009;20:363-79.
83. Gonzales PA, Zhou H, Pisitkun T, Wang NS, Star RA, Knepper MA, et al. Isolation and purification of exosomes in urine. Methods Mol Biol. 2010;641:89-99.
84. Pisitkun T, Johnstone R, Knepper MA. Discovery of urinary biomarkers. Mol Cell Proteomics. 2006;5:1760-71.
85. Zhou H, Yuen PS, Pisitkun T, Gonzales PA, Yasuda H, Dear JW, et al. Collection, storage, preservation, and normalization of human urinary exosomes for biomarker discovery. Kidney Int. 2006;69:1471-6.
86. Cheruvanky A, Zhou H, Pisitkun T, Kopp JB, Knepper MA, Yuen PS, et al. Rapid isolation of urinary exosomal biomarkers using a nanomembrane ultrafiltration concentrator. Am J Physiol Renal Physiol. 2007;292:F1657-61.
87. Merchant ML, Powell DW, Wilkey DW, Cummins TD, Deegens JK, Rood IM, et al. Microfiltration isolation of human urinary exosomes for characterization by MS. Proteomics Clin Appl. 2010;4:84-96.
88. Taylor DD, Zacharias W, Gercel-Taylor C. Exosome isolation for proteomic analyses and RNA profiling. Methods Mol Biol. 2011;728:235-46.
89. Alvarez ML, Khosroheidari M, Kanchi Ravi R, DiStefano JK. Comparison of protein, microRNA, and mRNA yields using different methods of urinary exosome isolation for the discovery of kidney disease biomarkers. Kidney Int. 2012;82:1024-32.
90. Alvarez ML, DiStefano JK. Towards microRNA-based therapeutics for diabetic nephropathy. Diabetologia. 2012;56:444-56.
91. Ebert MS, Neilson JR, Sharp PA. MicroRNA sponges: competitive inhibitors of small RNAs in mammalian cells. Nat Methods. 2007;4:721-6.
92. Stenvang J, Petri A, Lindow M, Obad S, Kauppinen S. Inhibition of microRNA function by antimiR oligonucleotides. Silence. 2012;3:1.
93. Esau CC. Inhibition of microRNA with antisense oligonucleotides. Methods. 2008;44:55-60.
94. •• Krutzfeldt J, Rajewsky N, Braich R, Rajeev KG, Tuschl T, Manoharan M, et al. Silencing of microRNAs in vivo with 'antagomirs'. Nature. 2005;438:685-9. Intravenous administration of antagomirs against miR-16, miR-122, miR-192 and miR-194 resulted in a marked reduction of corresponding miRNA levels in many organs including kidney.
95. Broderick JA, Zamore PD. MicroRNA therapeutics. Gene Ther. 2011;18:1104-10.
96. Grimm D, Streetz KL, Jopling CL, Storm TA, Pandey K, Davis CR, et al. Fatality in mice due to oversaturation of cellular microRNA/short hairpin RNA pathways. Nature. 2006;441:537-41.
97. An DS, Qin FX, Auyeung VC, Mao SH, Kung SK, Baltimore D, et al. Optimization and functional effects of stable short hairpin RNA expression in primary human lymphocytes via lentiviral vectors. Mol Ther. 2006;14:494-504.
98. Giering JC, Grimm D, Storm TA, Kay MA. Expression of shRNA from a tissue-specific pol II promoter is an effective and safe RNAi therapeutic. Mol Ther. 2008;16:1630-6.