Improving Molecular Therapy in the Kidney

mRNA-based vaccines and therapies - a revolutionary approach for conquering fast-spreading infections and other clinical applications: a review

Since the beginning of the COVID-19 pandemic, the development of messenger RNA (mRNA) vaccines has made significant progress in the pharmaceutical industry. The two COVID-19 mRNA vaccines from Moderna and Pfizer/BioNTech have been approved for marketing and have made significant contributions to preventing the spread of SARS-CoV-2. In addition, mRNA therapy has brought hope to some diseases that do not have specific treatment methods or are difficult to treat, such as the Zika virus and influenza virus infections, as well as the prevention and treatment of tumors. With the rapid development of in vitro transcription (IVT) technology, delivery systems, and adjuvants, mRNA therapy has also been applied to hereditary diseases such as Fabry's disease. This article reviews the recent development of mRNA vaccines for structural modification, treatment and prevention of different diseases; delivery carriers and adjuvants; and routes of administration to promote the clinical application of mRNA therapies.

Nanoparticle-mediated Klotho gene therapy prevents acute kidney injury to chronic kidney disease transition through regulating PPARα signaling in renal tubular epithelial cells

Klotho is an anti-aging protein produced primarily by tubular epithelial cells (TECs). Down-regulated expression of Klotho in injured TECs plays a key pathogenic role in promoting acute kidney injury (AKI) to chronic kidney disease (CKD) transition, yet therapeutic approaches targeting the restoration of renal Klotho levels remain challenging for clinical application. Here, we synthesize polydopamine-polyethylenimine-l-serine-Klotho plasmid nanoparticles (PPSK NPs), which can safely and selectively deliver the Klotho gene to the injured TECs through binding kidney injury molecule-1 and maintain the expression of Klotho protein. In vitro, PPSK NPs effectively reduce the hypoxia-reoxygenation-induced reactive oxygen species production and fibrotic gene expression. In the unilateral ischemia-reperfusion injury- and folic acid-induced AKI-CKD transition mouse models, a single low-dose injection of PPSK NPs is sufficient to preserve the normal kidney architecture and prevent renal fibrosis. Mechanismly, the protective effect of PPSK NPs relies on upregulating a key molecule peroxisome proliferator-activated receptor alpha (PPARα) via the inhibition of p38 and JNK phosphorylation, which in turn improves tubular fatty acid beta-oxidation and reduces renal lipid accumulation, thereby protecting against kidney fibrosis. In conclusion, our results highlight the translational potential of nanoparticle-based Klotho gene therapy in preventing the AKI-CKD transition.

Evolving adeno-associated viruses for gene transfer to the kidney via cross-species cycling of capsid libraries

The difficulty of delivering genes to the kidney has limited the translation of genetic medicines, particularly for the more than 10% of the global population with chronic kidney disease. Here we show that new variants of adeno-associated viruses (AAVs) displaying robust and widespread transduction in the kidneys of mice, pigs and non-human-primates can be obtained by evolving capsid libraries via cross-species cycling in different kidney models. Specifically, the new variants, AAV.k13 and AAV.k20, were enriched from the libraries following sequential intravenous cycling through mouse and pig kidneys, ex vivo cycling in human organoid cultures, and ex vivo machine perfusion in isolated kidneys from rhesus macaques. The two variants transduced murine kidneys following intravenous administration, with selective tropism for proximal tubules, and led to markedly higher transgene expression than parental AAV9 vectors in proximal tubule epithelial cells within human organoid cultures and in autotransplanted pig kidneys. Following ureteral delivery, AAV.k20 efficiently transduced kidneys in pigs and macaques. The AAV.k13 and AAV.k20 variants are promising vectors for therapeutic gene-transfer applications in kidney diseases and transplantation.

Prospects for gene therapy in polycystic kidney disease

PURPOSE OF REVIEW

We aim to provide an updated perspective on the recent advancements in gene therapy for polycystic kidney disease (PKD), a genetic disorder with significant morbidity. Given the rapid evolution of gene therapy technologies and their potential for treating inherited diseases, this review explores the therapeutic prospects and challenges in applying these technologies to PKD.

RECENT FINDINGS

Significant progress has been made in understanding the genetic underpinnings of PKD, making it a prime candidate for gene therapy. Re-expression of the PKD genes, treatment with the C-terminal tail of polycystin 1 protein and antagomir therapy against miR-17 have shown promise in reducing cyst formation and preserving kidney function. The rapid development of gene-editing tools, antisense oligonucleotide-based strategies, programmable RNA, and advanced gene delivery systems has opened new possibilities for PKD treatment. However, challenges such as off-target effects, delivery efficiency, and long-term safety remain significant barriers to clinical application.

SUMMARY

Current research highlights the transformative potential of gene therapy for PKD. Ongoing studies are crucial to overcoming existing challenges and translating these findings into clinical practice. We highlight the need for multidisciplinary efforts to optimize gene-editing technologies and ensure their safety and efficacy in treating PKD.

Gene therapy and kidney diseases

Chronic kidney disease (CKD) poses a significant global health challenge, projected to become one of the leading causes of death by 2040. Current treatments primarily manage complications and slow progression, highlighting the urgent need for personalized therapies targeting the disease-causing genes. Our increased understanding of the underlying genomic changes that lead to kidney diseases coupled with recent successful gene therapies targeting specific kidney cells have turned gene therapy and genome editing into a promising therapeutic approach for treating kidney disease. This review paper reflects on different delivery routes and systems that can be exploited to target specific kidney cells and the ways that gene therapy can be used to improve kidney health.

Targeted gene therapy for rare genetic kidney diseases

Chronic kidney disease is one of the leading causes of mortality worldwide because of kidney failure and the associated challenges of its treatment including dialysis and kidney transplantation. About one-third of chronic kidney disease cases are linked to inherited monogenic factors, making them suitable for potential gene therapy interventions. However, the intricate anatomical structure of the kidney poses a challenge, limiting the effectiveness of targeted gene delivery to the renal system. In this review, we explore the progress made in the field of targeted gene therapy approaches and their implications for rare genetic kidney disorders, examining preclinical studies and prospects for clinical application. In vivo gene therapy is most commonly used for kidney-targeted gene delivery and involves administering viral and nonviral vectors through various routes such as systemic, renal vein, and renal arterial injections. Small nucleic acids have also been used in preclinical and clinical studies for treating certain kidney disorders. Unexpectedly, hematopoietic stem and progenitor cells have been used as an ex vivo gene therapy vehicle for kidney gene delivery, highlighting their ability to differentiate into macrophages within the kidney, forming tunneling nanotubes that can deliver genetic material and organelles to adjacent kidney cells, even across the basement membrane to target the proximal tubular cells. As gene therapy technologies continue to advance and our understanding of kidney biology deepens, there is hope for patients with genetic kidney disorders to eventually avoid kidney transplantation.

ALKBH5 insufficiency protects against ferroptosis-driven cisplatin-induced renal cytotoxicity

In the clinical setting, cisplatin-induced nephrotoxicity primarily manifests as acute kidney injury (AKI). Recent studies have indicated that ferroptosis, a type of iron-dependent cell death, is closely involved in the cisplatin nephrotoxicity. AlkB homologue 5 (ALKBH5), an N6-methyladenosine (m6A) eraser protein expressed in various tissues, including the kidneys, has been implicated in this process. However, the specific role of ALKBH5 in cisplatin-induced nephrotoxicity remains unknown. Our findings indicated that ALKBH5 was upregulated in cisplatin-induced AKI, and the in vivo study results were consistent with the results of the in vitro study. Additionally, ALKBH5 knockout in transgenic animals was found to mitigate cisplatin-induced renal dysfunction, whereas its knock-in exacerbated the effects. Our study revealed that ALKBH5 controls the traditional ferroptosis metabolic pathway, leading to worsening of AKI in experiments conducted both in vivo and in vitro. The efficacy of pharmacological intervention targeting ALKBH5 in AKI animal models was demonstrated, and ALKBH5-based gene therapy confirmed these findings and displayed renoprotective effects against AKI. In conclusion, this study highlighted the crucial role of ALKBH5 as a key regulator of AKI. Overall, our research demonstrates the significant impact of ALKBH5 in controlling ferroptosis in cisplatin-induced AKI, suggesting that focusing on ALKBH5 could be a promising approach for treating cisplatin-related kidney damage.

The renal apical sodium-dependent bile acid transporter expression rescue attenuates renal damage in diabetic nephropathy via farnesoid X receptor activation

AIM

Bile acids (BA) function as signalling molecules regulating glucose-lipid homeostasis and energy expenditure. However, the expression of the apical sodium-dependent bile acid transporter (ASBT) in the kidney, responsible for renal BA reabsorption, is downregulated in patients with diabetic kidney disease (DKD). Using the db/db mouse model of DKD, this study aimed to investigate the effects of rescuing ASBT expression via adeno-associated virus-mediated delivery of ASBT (AAVASBT) on kidney protection.

METHODS

Six-week-old male db/db mice received an intraparenchymal injection of AAVASBT at a dose of 1 × 1011 viral genomes (vg)/animal and were subsequently fed a chow diet for 2 weeks. Male db/m mice served as controls. For drug treatment, daily intraperitoneal (i.p.) injections of the farnesoid X receptor (FXR) antagonist guggulsterone (GS, 10 mg/kg) were administered one day after initiating the experiment.

RESULTS

AAVASBT treatment rescued renal ASBT expression and reduced the urinary BA output in db/db mice. AAVASBT treatment activated kidney mitochondrial biogenesis and ameliorated renal impairment associated with diabetes by activating FXR. In addition, the injection of FXR antagonist GS in DKD mice would reverse these beneficial effects by AAVASBT treatment.

CONCLUSION

Our work indicated that restoring renal ASBT expression slowed the course of DKD via activating FXR. FXR activation stimulates mitochondrial biogenesis while reducing renal oxidative stress and lipid build up, indicating FXR activation's crucial role in preventing DKD. These findings further suggest that the maintenance of renal BA reabsorption could be a viable treatment for DKD.

Management of Microcomplications of Diabetes Mellitus: Challenges, Current Trends, and Future Perspectives in Treatment

Diabetes mellitus is a chronic metabolic disorder characterized by high blood sugar levels, which can lead to severe health issues if not managed effectively. Recent statistics indicate a significant global impact, with 463 million adults diagnosed worldwide and this projected to rise to 700 million by 2045. Type 1 diabetes is an autoimmune disorder where the immune system attacks pancreatic beta cells, reducing insulin production. Type 2 diabetes is primarily due to insulin resistance. Both types of diabetes are linked to severe microvascular and macrovascular complications if unmanaged. Microvascular complications, such as diabetic retinopathy, nephropathy, and neuropathy, result from damage to small blood vessels and can lead to organ and tissue dysfunction. Chronic hyperglycemia plays a central role in the onset of these complications, with prolonged high blood sugar levels causing extensive vascular damage. The emerging treatments and current research focus on various aspects, from insulin resistance to the intricate cellular damage induced by glucose toxicity. Understanding and intervening in these pathways are critical for developing effective treatments and managing diabetes long term. Furthermore, ongoing health initiatives, such as increasing awareness, encouraging early detection, and improving treatments, are in place to manage diabetes globally and mitigate its impact on health and society. These initiatives are a testament to the collective effort to combat this global health challenge.

Nmnat1 Deficiency Causes Mitoribosome Excess in Diabetic Nephropathy Mediated by Transcriptional Repressor HIC1

Nicotinamide adenine dinucleotide (NAD) is involved in renal physiology and is synthesized by nicotinamide mononucleotide adenylyltransferase (NMNAT). NMNAT exists as three isoforms, namely, NMNAT1, NMNAT2, and NMNAT3, encoded by Nmnat1, Nmnat2, and Nmnat3, respectively. In diabetic nephropathy (DN), NAD levels decrease, aggravating renal fibrosis. Conversely, sodium-glucose cotransporter-2 inhibitors increase NAD levels, mitigating renal fibrosis. In this regard, renal NAD synthesis has recently gained attention. However, the renal role of Nmnat in DN remains uncertain. Therefore, we investigated the role of Nmnat by establishing genetically engineered mice. Among the three isoforms, NMNAT1 levels were markedly reduced in the proximal tubules (PTs) of db/db mice. We examined the phenotypic changes in PT-specific Nmnat1 conditional knockout (CKO) mice. In CKO mice, Nmnat1 expression in PTs was downregulated when the tubules exhibited albuminuria, peritubular type IV collagen deposition, and mitochondrial ribosome (mitoribosome) excess. In CKO mice, Nmnat1 deficiency-induced mitoribosome excess hindered mitoribosomal translation of mitochondrial inner membrane-associated oxidative phosphorylation complex I (CI), CIII, CIV, and CV proteins and mitoribosomal dysfunction. Furthermore, the expression of hypermethylated in cancer 1, a transcription repressor, was downregulated in CKO mice, causing mitoribosome excess. Nmnat1 overexpression preserved mitoribosomal function, suggesting its protective role in DN.

Strategies for non-viral vectors targeting organs beyond the liver

In recent years, nanoparticles have evolved to a clinical modality to deliver diverse nucleic acids. Rising interest in nanomedicines comes from proven safety and efficacy profiles established by continuous efforts to optimize physicochemical properties and endosomal escape. However, despite their transformative impact on the pharmaceutical industry, the clinical use of non-viral nucleic acid delivery is limited to hepatic diseases and vaccines due to liver accumulation. Overcoming liver tropism of nanoparticles is vital to meet clinical needs in other organs. Understanding the anatomical structure and physiological features of various organs would help to identify potential strategies for fine-tuning nanoparticle characteristics. In this Review, we discuss the source of liver tropism of non-viral vectors, present a brief overview of biological structure, processes and barriers in select organs, highlight approaches available to reach non-liver targets, and discuss techniques to accelerate the discovery of non-hepatic therapies.

Persistent transgene expression in peripheral tissues one year post intravenous and intramuscular administration of AAV vectors containing the alphaherpesvirus latency-associated promoter 2

Significant progress has been made in enhancing recombinant adeno-associated virus (rAAV) for clinical investigation. Despite its versatility as a gene delivery platform, the inherent packaging constraint of 4.7 kb imposes restrictions on the range of diseases it can address. In this context, we present findings of an exceptionally compact and long-term promoter that facilitates the expression of larger genes compared to conventional promoters. This compact promoter originated from the genome of the alphaherpesvirus pseudorabies virus, latency-associated promoter 2 (LAP2, 404 bp). Promoter driving an mCherry reporter was packaged into single strand (ss) AAV8 and AAV9 vectors and injected into adult C57BL/6 mice at a dose of 5 × 1011 vg/mouse by single intravenous or intramuscular administration. An ssAAV8 and ssAAV9 vector with elongation factor-1α promoter (EF1α, 1264 bp) was injected side-by-side for comparison. After 400 days, we sacrificed the mice and examined mCherry expression in liver, kidney, heart, lung, spleen, pancreas, skeletal muscle, and brain. We found that LAP2 exhibited robust transgene expression across a wide range of cells and tissues comparable to the larger EF1α, which is currently recognized as a rather potent and ubiquitous promoter. The AAV8-LAP2 and AAV9-LAP2 constructs displayed strong transduction and transcription in liver, kidney, and skeletal muscle on both route of administration. However, no expression was detected in the heart, lung, spleen, pancreas, and brain. The outcomes of our investigation propose the viability of LAP2 for gene therapy applications demanding the expression of large or multiple therapeutic genes following a single viralvector administration.

Current Status and Prospects of Viral Vector-Based Gene Therapy to Treat Kidney Diseases

Inherited kidney diseases are among the leading causes of chronic kidney disease, reducing the quality of life and resulting in substantial socioeconomic impact. The advent of early genetic testing and the growing understanding of the molecular basis and pathophysiology of these disorders have opened avenues for novel treatment strategies. Viral vector-based gene therapies have evolved from experimental treatments for rare diseases to potent platforms that carry the intrinsic potential to provide a cure with a single application. Several gene therapy products have reached the market, and the numbers are only expected to increase. Still, none target inherited kidney diseases. Gene transfer to the kidney has lagged when compared to other tissue-directed therapies such as hepatic, neuromuscular, and ocular tissues. Systemic delivery of genetic information to tackle kidney disease is challenging. The pharma industry is taking steps to take on kidney disease and to translate the current research into the therapeutic arena. In this review, we provide an overview of the current viral vector-based approaches and their potential. We discuss advances in platforms and injection routes that have been explored to enhance gene delivery toward kidney cells in animal models, and how these can fuel the development of viable gene therapy products for humans.

RNA therapeutics for kidney injury

RNA therapy involves utilizing RNA-based molecules to control biological pathways, aiming to cure specific diseases. As our understanding of RNA functions and their roles has expanded, the application of RNA therapies has broadened to target various therapeutic points. This approach holds promise for treating a range of diseases, including kidney diseases. Therapeutic RNA can be employed to target specific genes or pathways implicated in the development of kidney conditions, such as inflammation, fibrosis, and oxidative stress. This review highlights the therapeutic potential of RNA-based therapies across different types of kidney diseases, encompassing infection, inflammation, nephrotoxicity, and ischemia/reperfusion injury. Furthermore, studies have pinpointed the specific kidney cells involved in RNA therapy. To address challenges hindering the potential impact of RNA-based drugs on their targets, nanotechnology is integrated, and RNA-loaded vehicles with ligands are explored for more efficient outcomes.

mRNA as a medicine in nephrology: the future is now

The successful employment of messenger RNA (mRNA) as vaccine therapy for the prevention of COVID-19 infection has spotlighted the attention of scientific community onto the potential clinical application of these molecules as innovative and alternative therapeutic approaches in different fields of medicine. As therapy, mRNAs may be advantageous due to their unique biological properties of targeting almost any genetic component within the cell, many of which may be unreachable using other pharmacological/therapeutic approaches, and encoding any proteins and peptides without the need for their transport into the nuclei of the target cells. Additionally, these molecules may be rapidly designed/produced and clinically tested. Once the chemistry of the RNA and its delivery system are optimized, the cost of developing novel variants of these medications for new selected clinical disorders is significantly reduced. However, although potentially useful as new therapeutic weapons against several kidney diseases, the complex architecture of kidney and the inability of nanoparticles that accommodate oligonucleotides to cross the integral glomerular filtration barrier have largely decreased their potential employment in nephrology. However, in the next few years, the technical improvements in mRNA that increase translational efficiency, modulate innate and adaptive immunogenicity, and increase their delivery at the site of action will overcome these limitations. Therefore, this review has the scope of summarizing the key strengths of these RNA-based therapies and illustrating potential future directions and challenges of this promising technology for widespread therapeutic use in nephrology.

The genetics and pathogenesis of CAKUT

Congenital anomalies of the kidney and urinary tract (CAKUT) comprise a large variety of malformations that arise from defective kidney or urinary tract development and frequently lead to kidney failure. The clinical spectrum ranges from severe malformations, such as renal agenesis, to potentially milder manifestations, such as vesicoureteral reflux. Almost 50% of cases of chronic kidney disease that manifest within the first three decades of life are caused by CAKUT. Evidence suggests that a large number of CAKUT are genetic in origin. To date, mutations in ~54 genes have been identified as monogenic causes of CAKUT, contributing to 12-20% of the aetiology of the disease. Pathogenic copy number variants have also been shown to cause CAKUT and can be detected in 4-11% of patients. Furthermore, environmental and epigenetic factors can increase the risk of CAKUT. The discovery of novel CAKUT-causing genes is challenging owing to variable expressivity, incomplete penetrance and variable genotype-phenotype correlation. However, such a discovery could ultimately lead to improvements in the accurate molecular genetic diagnosis, assessment of prognosis and multidisciplinary clinical management of patients with CAKUT, potentially including personalized therapeutic approaches.

Cell and gene therapy for kidney disease

Kidney disease is a leading cause of morbidity and mortality across the globe. Current interventions for kidney disease include dialysis and renal transplantation, which have limited efficacy or availability and are often associated with complications such as cardiovascular disease and immunosuppression. There is therefore a pressing need for novel therapies for kidney disease. Notably, as many as 30% of kidney disease cases are caused by monogenic disease and are thus potentially amenable to genetic medicine, such as cell and gene therapy. Systemic disease that affects the kidney, such as diabetes and hypertension, might also be targetable by cell and gene therapy. However, although there are now several approved gene and cell therapies for inherited diseases that affect other organs, none targets the kidney. Promising recent advances in cell and gene therapy have been made, including in the kidney research field, suggesting that this form of therapy might represent a potential solution for kidney disease in the future. In this Review, we describe the potential for cell and gene therapy in treating kidney disease, focusing on recent genetic studies, key advances and emerging technologies, and we describe several crucial considerations for renal genetic and cell therapies.

Enhancing the expression of a key mitochondrial enzyme at the inception of ischemia-reperfusion injury can boost recovery and halt the progression of acute kidney injury

Hydrodynamic fluid delivery has shown promise in influencing renal function in disease models. This technique provided pre-conditioned protection in acute injury models by upregulating the mitochondrial adaptation, while hydrodynamic injections of saline alone have improved microvascular perfusion. Accordingly, hydrodynamic mitochondrial gene delivery was applied to investigate the ability to halt progressive or persistent renal function impairment following episodes of ischemia-reperfusion injuries known to induce acute kidney injury (AKI). The rate of transgene expression was approximately 33% and 30% in rats with prerenal AKI that received treatments 1 (T1hr) and 24 (T24hr) hours after the injury was established, respectively. The resulting mitochondrial adaptation via exogenous IDH2 (isocitrate dehydrogenase 2 (NADP+) and mitochondrial) significantly blunted the effects of injury within 24 h of administration: decreased serum creatinine (≈60%, p < 0.05 at T1hr; ≈50%, p < 0.05 at T24hr) and blood urea nitrogen (≈50%, p < 0.05 at T1hr; ≈35%, p < 0.05 at T24hr) levels, and increased urine output (≈40%, p < 0.05 at T1hr; ≈26%, p < 0.05 at T24hr) and mitochondrial membrane potential, Δψm, (≈ by a factor of 13, p < 0.001 at T1hr; ≈ by a factor of 11, p < 0.001 at T24hr), despite elevated histology injury score (26%, p < 0.05 at T1hr; 47%, p < 0.05 at T24hr). Therefore, this study identifies an approach that can boost recovery and halt the progression of AKI at its inception.

Bardet-Biedl Syndrome: Current Perspectives and Clinical Outlook

The Bardet Biedl syndrome (BBS) is a rare inherited disorder considered a model of non-motile ciliopathy. It is in fact caused by mutations of genes encoding for proteins mainly localized to the base of the cilium. Clinical features of BBS patients are widely shared with patients suffering from other ciliopathies, especially autosomal recessive syndromic disorders; moreover, mutations in cilia-related genes can cause different clinical ciliopathy entities. Besides the best-known clinical features, as retinal degeneration, learning disabilities, polydactyly, obesity and renal defects, several additional clinical signs have been reported in BBS, expanding our understanding of the complexity of its clinical spectrum. The present review aims to describe the current knowledge of BBS i) pathophysiology, ii) clinical manifestations, highlighting both the most common and the less described features, iii) current and future perspective for treatment.

The potential of RNA-based therapy for kidney diseases

Inherited kidney diseases (IKDs) are a large group of disorders affecting different nephron segments, many of which progress towards kidney failure due to the absence of curative therapies. With the current advances in genetic testing, the understanding of the molecular basis and pathophysiology of these disorders is increasing and reveals new potential therapeutic targets. RNA has revolutionized the world of molecular therapy and RNA-based therapeutics have started to emerge in the kidney field. To apply these therapies for inherited kidney disorders, several aspects require attention. First, the mRNA must be combined with a delivery vehicle that protects the oligonucleotides from degradation in the blood stream. Several types of delivery vehicles have been investigated, including lipid-based, peptide-based, and polymer-based ones. Currently, lipid nanoparticles are the most frequently used formulation for systemic siRNA and mRNA delivery. Second, while the glomerulus and tubules can be reached by charge- and/or size-selectivity, delivery vehicles can also be equipped with antibodies, antibody fragments, targeting peptides, carbohydrates or small molecules to actively target receptors on the proximal tubule epithelial cells, podocytes, mesangial cells or the glomerular endothelium. Furthermore, local injection strategies can circumvent the sequestration of RNA formulations in the liver and physical triggers can also enhance kidney-specific uptake. In this review, we provide an overview of current and potential future RNA-based therapies and targeting strategies that are in development for kidney diseases, with particular interest in inherited kidney disorders.

Still finding ways to augment the existing management of acute and chronic kidney diseases with targeted gene and cell therapies: Opportunities and hurdles

The rising global incidence of acute and chronic kidney diseases has increased the demand for renal replacement therapy. This issue, compounded with the limited availability of viable kidneys for transplantation, has propelled the search for alternative strategies to address the growing health and economic burdens associated with these conditions. In the search for such alternatives, significant efforts have been devised to augment the current and primarily supportive management of renal injury with novel regenerative strategies. For example, gene- and cell-based approaches that utilize recombinant peptides/proteins, gene, cell, organoid, and RNAi technologies have shown promising outcomes primarily in experimental models. Supporting research has also been conducted to improve our understanding of the critical aspects that facilitate the development of efficient gene- and cell-based techniques that the complex structure of the kidney has traditionally limited. This manuscript is intended to communicate efforts that have driven the development of such therapies by identifying the vectors and delivery routes needed to drive exogenous transgene incorporation that may support the treatment of acute and chronic kidney diseases.

Unlocking the promise of mRNA therapeutics

The extraordinary success of mRNA vaccines against coronavirus disease 2019 (COVID-19) has renewed interest in mRNA as a means of delivering therapeutic proteins. Early clinical trials of mRNA therapeutics include studies of paracrine vascular endothelial growth factor (VEGF) mRNA for heart failure and of CRISPR-Cas9 mRNA for a congenital liver-specific storage disease. However, a series of challenges remains to be addressed before mRNA can be established as a general therapeutic modality with broad relevance to both rare and common diseases. An array of new technologies is being developed to surmount these challenges, including approaches to optimize mRNA cargos, lipid carriers with inherent tissue tropism and in vivo percutaneous delivery systems. The judicious integration of these advances may unlock the promise of biologically targeted mRNA therapeutics, beyond vaccines and other immunostimulatory agents, for the treatment of diverse clinical indications.

Nano-Technological Approaches for Targeting Kidney Diseases With Focus on Diabetic Nephropathy: Recent Progress, and Future Perspectives

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide. With the rising prevalence of diabetes, the occurrence of DN is likely to hit pandemic proportions. The current treatment strategies employed for DN focus on the management of blood pressure, glycemia, and cholesterol while neglecting DN’s molecular progression mechanism. For many theranostic uses, nano-technological techniques have evolved in biomedical studies. Several nanotechnologically based theranostics have been devised that can be tagged with targeting moieties for both drug administration and/or imaging systems and are being studied to identify various clinical conditions. The molecular mechanisms involved in DN are discussed in this review to assist in understanding its onset and progression pattern. We have also discussed emerging strategies for establishing a nanomedicine-based platform for DN-targeted drug delivery to increase drug’s efficacy and safety, as well as their reported applications.

Genetic Kidney Diseases (GKDs) Modeling Using Genome Editing Technologies

Genetic kidney diseases (GKDs) are a group of rare diseases, affecting approximately about 60 to 80 per 100,000 individuals, for which there is currently no treatment that can cure them (in many cases). GKDs usually leads to early-onset chronic kidney disease, which results in patients having to undergo dialysis or kidney transplant. Here, we briefly describe genetic causes and phenotypic effects of six GKDs representative of different ranges of prevalence and renal involvement (ciliopathy, glomerulopathy, and tubulopathy). One of the shared characteristics of GKDs is that most of them are monogenic. This characteristic makes it possible to use site-specific nuclease systems to edit the genes that cause GKDs and generate in vitro and in vivo models that reflect the genetic abnormalities of GKDs. We describe and compare these site-specific nuclease systems (zinc finger nucleases (ZFNs), transcription activator-like effect nucleases (TALENs) and regularly clustered short palindromic repeat-associated protein (CRISPR-Cas9)) and review how these systems have allowed the generation of cellular and animal GKDs models and how they have contributed to shed light on many still unknown fields in GKDs. We also indicate the main obstacles limiting the application of these systems in a more efficient way. The information provided here will be useful to gain an accurate understanding of the technological advances in the field of genome editing for GKDs, as well as to serve as a guide for the selection of both the genome editing tool and the gene delivery method most suitable for the successful development of GKDs models.

Gene therapy for kidney disease: targeting cystinuria

PURPOSE OF REVIEW

The aim of this study was to summarize recent findings in kidney gene therapy while proposing cystinuria as a model kidney disease target for genome engineering therapeutics.

RECENT FINDINGS

Despite the advances of gene therapy for treating diseases of other organs, the kidney lags behind. Kidney-targeted gene delivery remains an obstacle to gene therapy of kidney disease. Nanoparticle and adeno-associated viral vector technologies offer emerging hope for kidney gene therapy. Cystinuria represents a model potential target for kidney gene therapy due to its known genetic and molecular basis, targetability, and capacity for phenotypic rescue.

SUMMARY

Although gene therapy for kidney disease remains a major challenge, new and evolving technologies may actualize treatment for cystinuria and other kidney diseases.

From Basic Science to Clinical Translation in Kidney Cancer: A Report from the Second Kidney Cancer Research Summit

The second Kidney Cancer Research Summit was held virtually in October 2020. The meeting gathered worldwide experts in the field of kidney cancer, including basic, translational, and clinical scientists as well as patient advocates. Novel studies were presented, addressing areas of unmet need related to different topics. These include novel metabolic targets, promising immunotherapeutic regimens, predictive genomic and transcriptomic biomarkers, and variant histologies of renal cell carcinoma (RCC). With the development of pioneering technologies, and an unprecedented commitment to kidney cancer research, the field has tremendously evolved. This perspective aims to summarize the different sessions of the conference, outline major advances in the understanding of RCC and discuss current challenges faced by the field.

Oligonucleotide-Based Therapies for Renal Diseases

The global burden of chronic kidney disease (CKD) is increasing every year and represents a great cost for public healthcare systems, as the majority of these diseases are progressive. Therefore, there is an urgent need to develop new therapies. Oligonucleotide-based drugs are emerging as novel and promising alternatives to traditional drugs. Their expansion corresponds with new knowledge regarding the molecular basis underlying CKD, and they are already showing encouraging preclinical results, with two candidates being evaluated in clinical trials. However, despite recent technological advances, efficient kidney delivery remains challenging, and the presence of off-targets and side-effects precludes development and translation to the clinic. In this review, we provide an overview of the various oligotherapeutic strategies used preclinically, emphasizing the most recent findings in the field, together with the different strategies employed to achieve proper kidney delivery. The use of different nanotechnological platforms, including nanocarriers, nanoparticles, viral vectors or aptamers, and their potential for the development of more specific and effective treatments is also outlined.