Safe Nanocomposite-Mediated Efficient Delivery of MicroRNA Plasmids for Autosomal Dominant Polycystic Kidney Disease (ADPKD) Therapy

Folate conjugated nanomedicines for selective inhibition of mTOR signaling in polycystic kidneys at clinically relevant doses

Although rapamycin is a very effective drug for rodents with polycystic kidney disease (PKD), it is not encouraging in the clinical trials due to the suboptimal dosages compelled by the off-target side effects. We here report the generation, characterization, specificity, functionality, pharmacokinetic, pharmacodynamic and toxicology profiles of novel polycystic kidney-specific-targeting nanoparticles (NPs). We formulated folate-conjugated PLGA-PEG NPs, which can be loaded with multiple drugs, including rapamycin (an mTOR inhibitor) and antioxidant 4-hydroxy-TEMPO (a nephroprotective agent). The NPs increased the efficacy, potency and tolerability of rapamycin resulting in an increased survival rate and improved kidney function by decreasing side effects and reducing biodistribution to other organs in PKD mice. The daily administration of rapamycin-alone (1 mg/kg/day) could now be achieved with a weekly injection of NPs containing rapamycin (379 μg/kg/week). This polycystic kidney-targeting nanotechnology, for the first time, integrated advances in the use of 1) nanoparticles as a delivery cargo, 2) folate for targeting, 3) near-infrared Cy5-fluorophore for in vitro and in vivo live imaging, 4) rapamycin as a pharmacological therapy, and 5) TEMPO as a combinational therapy. The slow sustained-release of rapamycin by polycystic kidney-targeting NPs demonstrates a new era of nanomedicine in treatment for chronic kidney diseases at clinically relevant doses.

Non-coding RNAs as potential biomarkers and therapeutic targets in polycystic kidney disease

Polycystic kidney disease (PKD) is a significant cause of end-stage kidney failure and there are few effective drugs for treating this inherited condition. Numerous aberrantly expressed non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), may contribute to PKD pathogenesis by participating in multiple intracellular and intercellular functions through post-transcriptional regulation of protein-encoding genes. Insights into the mechanisms of miRNAs and other ncRNAs in the development of PKD may provide novel therapeutic strategies. In this review, we discuss the current knowledge about the roles of dysregulated miRNAs and other ncRNAs in PKD. These roles involve multiple aspects of cellular function including mitochondrial metabolism, proliferation, cell death, fibrosis and cell-to-cell communication. We also summarize the potential application of miRNAs as biomarkers or therapeutic targets in PKD, and briefly describe strategies to overcome the challenges of delivering RNA to the kidney, providing a better understanding of the fundamental advances in utilizing miRNAs and other non-coding RNAs to treat PKD.

Secreted Neutrophil Gelatinase-Associated Lipocalin Shows Stronger Ability to Inhibit Cyst Enlargement of ADPKD Cells Compared with Nonsecreted Form

Polycystic kidney disease (PKD) is one of the most common inherited diseases and is characterized by the development of fluid-filled cysts along multiple segments of the nephron. Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of PKD, which is caused by mutations in either PKD1 or PKD2 genes that encode polycystin-1 (PC1) and polycystin-2 (PC2), respectively. As ADPKD progresses, cysts enlarge and disrupt normal kidney architecture, eventually leading to kidney failure. Our previous study showed that overexpression of exogenous kidney-specific neutrophil gelatinase-associated lipocalin (NGAL) reduced cyst progression and prolonged the lifespan of ADPKD mice (Pkd1^L3/L3, 2L3 for short). In this study, we attempted to explore the underlying mechanism of reduced cyst progression in the presence of NGAL using immortalized 2L3 cells. The results of MTT and BrdU incorporation assays showed that recombinant mouse NGAL (mNGAL) protein significantly decreased the viability and proliferation of 2L3 cells. Flow cytometry and western blot analyses showed that mNGAL inhibited activation of the ERK and AKT pathways and induced apoptosis and autophagy in 2L3 cells. In addition, a 3D cell culture platform was established to identify cyst progression in 2L3 cells and showed that mNGAL significantly inhibited cyst enlargement in 2L3 cells. Overexpression of secreted mNGAL (pN + LS) and nonsecreted mNGAL (pN − LS) repressed cell proliferation and cyst enlargement in 2L3 cells and had effects on markers involved in proliferation, apoptosis, and autophagy. However, secreted mNGAL had a more pronounced and consistent effect than that of nonsecreted form. These results reveal that secreted mNGAL has stronger ability to inhibit cyst enlargement of ADPKD cells than that of nonsecreted form. These findings could help to identify strategies for the future clinical treatment of ADPKD.

Limitations and opportunities in the pharmacotherapy of ciliopathies

Ciliopathies are a family of rather diverse conditions, which have been grouped based on the finding of altered or dysfunctional cilia, potentially motile, small cellular antennae extending from the surface of postmitotic cells. Cilia-related disorders include embryonically arising conditions such as Joubert, Usher or Kartagener syndrome, but also afflictions with a postnatal or even adult onset phenotype, i.e. autosomal dominant polycystic kidney disease. The majority of ciliopathies are syndromic rather than affecting only a single organ due to cilia being found on almost any cell in the human body. Overall ciliopathies are considered rare diseases. Despite that, pharmacological research and the strive to help these patients has led to enormous therapeutic advances in the last decade. In this review we discuss new treatment options for certain ciliopathies, give an outlook on promising future therapeutic strategies, but also highlight the limitations in the development of therapeutic approaches of ciliopathies.

Novel Application of Magnetite Nanoparticle-Mediated Vitamin D3 Delivery for Peritoneal Dialysis-Related Peritoneal Damage

PURPOSE

Vitamin D3 is useful for the treatment of peritoneal dialysis (PD)-related peritoneal damage, but its side effects, such as hypercalcemia and vascular calcification, limit its applicability. Thus, we developed vitamin D-loaded magnetic nanoparticles (MNPs) and determined their therapeutic efficacy and side effects in vivo.

MATERIALS AND METHODS

Alginate-modified MNPs were combined with 1α, 25 (OH)2D3 to generate vitamin D-loaded nanoparticles. The particles were conjugated with an antibody against peritoneum-glycoprotein M6A (GPM6A). The particles' ability to target the peritoneum was examined following intraperitoneal administration to mice and by monitoring their bio-distribution. We also established a PD animal model to determine the therapeutic and side effects of vitamin D-loaded MNPs in vivo.

RESULTS

Vitamin D-loaded MNPs targeted the peritoneum better than vitamin D3, and had the same therapeutic effect as vitamin D3 in ameliorating peritoneal fibrosis and functional deterioration in a PD animal model. Most importantly, the particles reduced the side effects of vitamin D3, such as hypercalcemia and body weight loss, in mice.

CONCLUSION

Vitamin D-loaded MNPs could be an ideal future therapeutic option to treat PD-related peritoneal damage.

Current Drug Nano-targeting Strategies for Improvement in the Diagnosis and Treatment of Prevalent Pathologies such as Cardiovascular and Renal Diseases

BACKGROUND

The kidney and cardiovascular system are closely related to each other during the modulation of the cardiovascular homeostasis. However, the search for new alternatives for the treatment and diagnosis of cardiovascular diseases does not take into account this relationship, so their evaluation results and the advantages offered by their global and integrative analysis are wasted. For example, a variety of receptors that are overexpressed in both pathologies is large enough to allow expansion in the search for new molecular targets and ligands. Nanotechnology offers pharmacological targeting strategies to kidney, heart, and blood vessels for overcoming one of the essential restrictions of traditional cardiovascular therapies the ones related to their unspecific pharmacodynamics distribution in these critical organs.

RECENT FINDINGS

Drug or contrast agent nano-targeting for treatment or diagnosis of atherosclerosis, thrombosis, renal cancer or fibrosis, glomerulonephritis, among other renal, cardiac and blood vessels pathologies would allow an increase in their efficacy and a reduction of their side effects. Such effects are possible because, through pharmacological targeting, the drug is mainly found at the desired site. Review Purpose: In this mini-review, active, passive, and physical targeting strategies of several nanocarriers that have been assessed and proposed for the treatment and diagnosis of different cardiovascular diseases, are being addressed.

A review of the application of nanoparticles in the diagnosis and treatment of chronic kidney disease

Chronic kidney disease (CKD) poses a great burden to global public health as current therapies are generally ineffective. Early detection and effective therapy are crucial for the future prevention and progression of CKD. Nanoparticles (NPs) vary by particle size, charge, shape and the density of targeting ligands and are associated with enhancement of the pharmacokinetic properties, targetability, or the bioavailability of drugs. Thus, the emergence of NPs in medicine has provided novel solutions to the potential diagnosis and treatment of CKD. This review describes the current experimental research, clinical applications of NPs, the current challenges, and upcoming opportunities in the diagnosis and treatment of CKD.

Identification of housekeeping genes for microRNA expression analysis in kidney tissues of Pkd1 deficient mouse models

Polycystic kidney disease is a complex clinical entity which comprises a group of genetic diseases that leads to renal cyst development. We evaluated the most suitable housekeeping genes for microRNA expression by RT-qPCR analyses of kidney tissues in Pkd1-deficient mouse models from a panel of five candidates genes (miR-20a, miR-25, miR-26a, miR-191 and U6) and 3 target genes (miR-17, miR-21 and let-7a) using samples from kidneys of cystic mice (Pkd1^flox/flox:Nestin^cre, CY), non-cystic controls (Pkd1^flox/flox, NC), Pkd1-haploinsufficient (Pkd1^+/−, HT), wild-type controls (Pkd1^+/+, WT), severely cystic mice (Pkd1^V/V, SC), wild-type controls (CO). The stability of the candidate genes was investigated using NormFinder, GeNorm, BestKeeper, DataAssist, and RefFinder software packages and the comparative ΔCt method. The analyses identified miR-26a as the most stable housekeeping gene for all kidney samples, miR-20a for CY and NC, miR-20a and miR-26a for HT and WT, and miR-25 and miR-26a for SC and CO. Expression of miR-21 was upregulated in SC compared to CO and trends of miR-21 upregulation and let-7a downregulation in CY and HT compared to its control kidneys, when normalized by different combinations of miR-20a, miR-25 and miR-26a. Our findings established miR-20a, miR-25, and miR-26a as the best housekeeping genes for miRNA expression analyses by RT-qPCR in kidney tissues of Pkd1-deficient mouse models.