ABSTRACT
Background: Polycystic kidney disease is a cystic genetic disease. There are two forms: an autosomal dominant one, more common and typical of adults, and an autosomal recessive one, rarer and present in childhood. The autosomal dominant form is caused by genetic mutations of the PKD1 gene in 85% of cases and of PKD2 in 10-15% of cases. Case Report: We reported a case of 56-year-old woman with ADPKD, who had a kidney transplant and who was hospitalized for respiratory failure from Covid 19 disease. She was intubated, sedated and dialyzed, treated with antibiotics, immunosuppressants, diuretics and heparin. CT scan of the abdomen showed multiple cysts of various sizes in the liver and multiple cysts in the kidneys. The patient died after 20 days because she was unresponsive to therapy. The autopsy showed milky ascitic fluid in the abdomen, massive gastric haemor-rhage, intestinal fungal plaques, hepatic and renal polycystosis. The kidneys measured a total of 27 cm with a total weight of about 9 kg. The liver parenchyma appeared cavernous with multiple cysts. The kidney cysts contained bloody liquid. Conclusions: The case demonstrates how important it is in these subjects to evaluate not only the kidneys but also the liver which could present polycystosis and cause liver failure, affecting the severity of the pathology and death. This data is important to emphasize in the clinical management of these patients a close monitoring of liver function also from a preventative perspective in life.
Subject(s)
COVID-19 , Polycystic Kidney, Autosomal Dominant , Humans , Polycystic Kidney, Autosomal Dominant/complications , Polycystic Kidney, Autosomal Dominant/genetics , Female , Middle Aged , Fatal Outcome , COVID-19/complications , Kidney Transplantation , Liver Diseases/etiologyABSTRACT
Renal cystic diseases are common conditions whose etiology can be highly heterogeneous. They require a correct approach for adequate diagnosis and management. We aimed to illustrate part of the spectrum of renal cystic diseases through some clinical cases managed in our service. We describe 11 clinical cases including clinical entities such as renal multicystic dysplasia, and autosomal dominant and autosomal recessive polycystic renal disease, among other pathologies. Renal cystic diseases are heterogeneous in their clinical presentation, natural history, radiological findings, and genetic and pathophysiological basis. An integral clinical approach is needed to get a clear etiological diagnosis and offer adequate individualized care and follow-up for patients.
Las enfermedades quísticas renales son condiciones frecuentes cuya etiología puede ser muy heterogénea, por lo que se requiere un adecuado abordaje para su diagnóstico y manejo. El objetivo de este trabajo fue ilustrar parte del espectro de la enfermedad renal quística por medio de casos clínicos manejados en la Fundación Valle del Lili. Se describen 11 casos clínicos que incluyen enfermedades como displasia multiquística renal, enfermedad poliquística renal autosómica dominante y autosómica recesiva, entre otras. Las enfermedades quísticas renales varían en su presentación clínica, historia natural, hallazgos imagenológicos, bases genéticas y fisiopatológicas, por consiguiente, el enfoque diagnóstico y el manejo integral se debe realizar de forma individualizada y con un abordaje multidisciplinario.
Subject(s)
Kidney Diseases, Cystic , Humans , Child , Male , Kidney Diseases, Cystic/genetics , Kidney Diseases, Cystic/diagnostic imaging , Female , Child, Preschool , Infant , Adolescent , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/diagnostic imaging , Polycystic Kidney, Autosomal Recessive/genetics , Polycystic Kidney, Autosomal Recessive/diagnostic imaging , Multicystic Dysplastic Kidney/genetics , Multicystic Dysplastic Kidney/diagnostic imagingABSTRACT
Polycystin-1 (PC-1) and PC-2 form a heteromeric ion channel complex that is abundantly expressed in primary cilia of renal epithelial cells. This complex functions as a non-selective cation channel, and mutations within the polycystin complex cause autosomal dominant polycystic kidney disease (ADPKD). The spatial and temporal regulation of the polycystin complex within the ciliary membrane remains poorly understood. Using both whole-cell and ciliary patch-clamp recordings, we identify a cilia-enriched oxysterol, 7ß,27-dihydroxycholesterol (DHC), that serves as a necessary activator of the polycystin complex. We further identify an oxysterol-binding pocket within PC-2 and showed that mutations within this binding pocket disrupt 7ß,27-DHC-dependent polycystin activation. Pharmacologic and genetic inhibition of oxysterol synthesis reduces channel activity in primary cilia. In summary, our findings reveal a regulator of the polycystin complex. This oxysterol-binding pocket in PC-2 may provide a specific target for potential ADPKD therapeutics.
Subject(s)
Cilia , TRPP Cation Channels , Cilia/metabolism , TRPP Cation Channels/metabolism , TRPP Cation Channels/genetics , Animals , Humans , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Oxysterols/metabolism , Patch-Clamp Techniques , HEK293 Cells , Mutation , Kidney/metabolism , Mice , Binding SitesABSTRACT
BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent genetic kidney disorder. While metformin has demonstrated the ability to inhibit cyst growth in animal models of ADPKD via activation of adenosine monophosphate-activated protein kinase (AMPK), its effectiveness in humans is limited due to its low potency. This study explored the impact of HL156A, a new and more potent AMPK activator, in a mouse model of ADPKD. METHODS: To investigate whether HL156A inhibits the proliferation of renal cyst cells in ADPKD in vitro, exogenous human telomerase reverse transcriptase (hTERT)-immortalized renal cyst cells from ADPKD patients were treated with HL156A, and an MTT (dimethylthiazol-diphenyltetrazolium bromide) assay was performed. To assess the cyst-inhibitory effect of HL156A in vivo, we generated Pkd1 conditional knockout (KO) mice with aquaporin 2 (AQP2)-Cre, which selectively expresses Cre recombinase in the collecting duct. The effectiveness of HL156A in inhibiting cyst growth and improving renal function was confirmed by measuring the number of cysts and blood urea nitrogen (BUN) levels in the collecting duct-specific Pkd1 KO mice. RESULTS: When cyst cells were treated with up to 20 µM of metformin or HL156A, HL156A reduced cell viability by 25% starting at a concentration of 5 µM, whereas metformin showed no effect. When AQP2-Cre male mice were crossed with Pkd1flox/flox female mice, and when AQP2-Cre female mice were crossed with Pkd1flox/flox male mice, the number of litters produced by both groups was comparable. In collecting duct-specific Pkd1 KO mice, HL156A was found to inhibit cyst growth, reducing both the number and size of cysts. Furthermore, it was confirmed that kidney function improved as HL156A treatment led to a reduction in elevated BUN levels. Lastly, it was observed that the increase in AMPK phosphorylation induced by HL156A decreased ERK phosphorylation and α-SMA expression. CONCLUSION: HL156A has potential as a drug that can restore kidney function in ADPKD patients by inhibiting cyst growth.
Subject(s)
AMP-Activated Protein Kinases , Polycystic Kidney, Autosomal Dominant , Animals , Polycystic Kidney, Autosomal Dominant/drug therapy , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/genetics , Mice , AMP-Activated Protein Kinases/metabolism , Humans , Mice, Knockout , Cell Proliferation/drug effects , Male , Disease Models, Animal , Cysts/drug therapy , Cysts/pathology , Cysts/metabolismABSTRACT
Multiple alterations of cellular metabolism have been documented in experimental studies of autosomal dominant polycystic kidney disease (ADPKD) and are thought to contribute to its pathogenesis. To elucidate the molecular pathways and transcriptional regulators associated with the metabolic changes of renal cysts in ADPKD, we compared global gene expression data from human PKD1 renal cysts, minimally cystic tissues (MCT) from the same patients, and healthy human kidney cortical tissue samples. We found gene expression profiles of PKD1 renal cysts were consistent with the Warburg effect with gene pathway changes favoring increased cellular glucose uptake and lactate production, instead of pyruvate oxidation. Additionally, mitochondrial energy metabolism was globally depressed, associated with downregulation of gene pathways related to fatty acid oxidation (FAO), branched-chain amino acid (BCAA) degradation, the Krebs cycle, and oxidative phosphorylation (OXPHOS) in renal cysts. Activation of mTORC1 and its two target proto-oncogenes, HIF-1α and MYC, was predicted to drive the expression of multiple genes involved in the observed metabolic reprogramming (e.g., GLUT3, HK1/HK2, ALDOA, ENO2, PKM, LDHA/LDHB, MCT4, PDHA1, PDK1/3, MPC1/2, CPT2, BCAT1, NAMPT); indeed, their predicted expression patterns were confirmed by our data. Conversely, we found AMPK inhibition was predicted in renal cysts. AMPK inhibition was associated with decreased expression of PGC-1α, a transcriptional coactivator for transcription factors PPARα, ERRα, and ERRγ, all of which play a critical role in regulating oxidative metabolism and mitochondrial biogenesis. These data provide a comprehensive map of metabolic pathway reprogramming in ADPKD and highlight nodes of regulation that may serve as targets for therapeutic intervention.
Subject(s)
Energy Metabolism , Polycystic Kidney, Autosomal Dominant , Systems Biology , Humans , Systems Biology/methods , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , TRPP Cation Channels/metabolism , TRPP Cation Channels/genetics , Mitochondria/metabolism , Mitochondria/genetics , Mechanistic Target of Rapamycin Complex 1/metabolism , Mechanistic Target of Rapamycin Complex 1/genetics , Oxidative Phosphorylation , Gene Expression RegulationABSTRACT
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a prevalent hereditary disorder that affects the kidneys, characterized by the development of an excessive number of fluid-filled cysts of varying sizes in both kidneys. Along with the progression of ADPKD, these enlarged cysts displace normal kidney tissue, often accompanied by interstitial fibrosis and inflammation, and significantly impair renal function, leading to end-stage renal disease. Currently, the precise mechanisms underlying ADPKD remain elusive, and a definitive cure has yet to be discovered. This review delineates the epidemiology, pathological features, and clinical diagnostics of ADPKD or ADPKD-like disease across human populations, as well as companion animals and other domesticated species. A light has been shed on pivotal genes and biological pathways essential for preventing and managing ADPKD, which underscores the importance of cross-species research in addressing this complex condition. Treatment options are currently limited to Tolvaptan, dialysis, or surgical excision of large cysts. However, comparative studies of ADPKD across different species hold promise for unveiling novel insights and therapeutic strategies to combat this disease.
Subject(s)
Polycystic Kidney, Autosomal Dominant , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/therapy , Polycystic Kidney, Autosomal Dominant/pathology , Humans , Animals , Kidney/pathology , Kidney/metabolism , Disease Models, AnimalABSTRACT
Patients with autosomal dominant polycystic kidney disease (ADPKD), a genetic disease due to mutations of the PKD1 or PKD2 gene, show signs of complement activation in the urine and cystic fluid, but their pathogenic role in cystogenesis is unclear. We tested the causal relationship between complement activation and cyst growth using a Pkd1KO renal tubular cell line and newly generated conditional Pkd1-/- C3-/- mice. Pkd1-deficient tubular cells have increased expression of complement-related genes (C3, C5, CfB, C3ar, and C5ar1), while the gene and protein expression of complement regulators DAF, CD59, and Crry is decreased. Pkd1-/- C3-/- mice are unable to fully activate the complement cascade and are characterized by a significantly slower kidney cystogenesis, preserved renal function, and reduced intrarenal inflammation compared with Pkd1-/- C3+/+ controls. Transgenic expression of the cytoplasmic C-terminal tail of Pkd1 in Pkd1KO cells lowered C5ar1 expression, restored Daf levels, and reduced cell proliferation. Consistently, both DAF overexpression and pharmacological inhibition of C5aR1 (but not C3aR) reduced Pkd1KO cell proliferation. In conclusion, the loss of Pkd1 promotes unleashed activation of locally produced complement by downregulating DAF expression in renal tubular cells. Increased C5a formation and C5aR1 activation in tubular cells promotes cyst growth, offering a new therapeutic target.
Subject(s)
CD55 Antigens , Complement C3 , Mice, Knockout , Polycystic Kidney, Autosomal Dominant , Animals , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/metabolism , Mice , CD55 Antigens/genetics , CD55 Antigens/metabolism , Complement C3/genetics , Complement C3/metabolism , Receptor, Anaphylatoxin C5a/metabolism , Receptor, Anaphylatoxin C5a/genetics , Disease Models, Animal , Complement Activation , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Humans , Cell Proliferation , Male , Cell Line , Receptors, Complement 3b/genetics , Receptors, Complement 3b/metabolismABSTRACT
Orexin-A is a neuropeptide product of the lateral hypothalamus that acts on two receptors, OX1R and OX2R. The orexinergic system is involved in feeding, sleep, and pressure regulation. Recently, orexin-A levels have been found to be negatively correlated with renal function. Here, we analyzed orexin-A levels as well as the incidence of SNPs in the hypocretin neuropeptide precursor (HCRT) and its receptors, HCRTR1 and HCRTR2, in 64 patients affected by autosomal dominant polycystic kidney disease (ADPKD) bearing truncating mutations in the PKD1 or PKD2 genes. Twenty-four healthy volunteers constituted the control group. Serum orexin-A was assessed by ELISA, while the SNPs were investigated through Sanger sequencing. Correlations with the main clinical features of PKD patients were assessed. PKD patients showed impaired renal function (mean eGFR 67.8 ± 34.53) and a statistically higher systolic blood pressure compared with the control group (p < 0.001). Additionally, orexin-A levels in PKD patients were statistically higher than those in healthy controls (477.07 ± 69.42 pg/mL vs. 321.49 ± 78.01 pg/mL; p < 0.001). Furthermore, orexin-A inversely correlated with blood pressure (p = 0.0085), while a direct correlation with eGFR in PKD patients was found. None of the analyzed SNPs showed any association with orexin-A levels in PKD. In conclusion, our data highlights the emerging role of orexin-A in renal physiology and its potential relevance to PKD. Further research is essential to elucidate the intricate mechanisms underlying orexin-A signaling in renal function and its therapeutic implications for PKD and associated cardiovascular complications.
Subject(s)
Orexin Receptors , Orexins , Polymorphism, Single Nucleotide , Humans , Orexins/metabolism , Orexins/genetics , Male , Female , Middle Aged , Orexin Receptors/metabolism , Orexin Receptors/genetics , Adult , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/blood , Case-Control Studies , Aged , Blood Pressure , Polycystic Kidney Diseases/genetics , Polycystic Kidney Diseases/metabolism , Polycystic Kidney Diseases/bloodABSTRACT
Alport Syndrome (AS) is the most common genetic glomerular disease, and it is caused by COL4A3, COL4A4, and COL4A5 pathogenic variants. The classic phenotypic spectrum associated with AS ranges from isolated hematuria to chronic kidney disease (CKD) with extrarenal abnormalities. Atypical presentation of the disorder is possible, and it can mislead the diagnosis. Polycystic kidney disease (PKD), which is most frequently associated with Autosomal Dominant PKD (ADPKD) due to PKD1 and PKD2 heterozygous variants, is emerging as a possible clinical manifestation in COL4A3-A5 patients. We describe a COL4A5 novel familial frameshift variant (NM_000495.5: c.1095dup p.(Leu366ValfsTer45)), which was associated with AS and PKD in the hemizygous proband, as well as with PKD, IgA glomerulonephritis and focal segmental glomerulosclerosis (FSGS) in the heterozygous mother. Establishing the diagnosis of AS can sometimes be difficult, especially in the context of misleading family history and atypical phenotypic features. This case study supports the emerging genotypic and phenotypic heterogeneity in COL4A3-A5-associated disorders, as well as the recently described association between PKD and collagen type IV (Col4) defects. We highlight the importance of the accurate phenotyping of all family members and the relevance of next-generation sequencing in the differential diagnosis of hereditary kidney disease.
Subject(s)
Collagen Type IV , Nephritis, Hereditary , Adult , Female , Humans , Male , Collagen Type IV/genetics , Frameshift Mutation , Nephritis, Hereditary/genetics , Nephritis, Hereditary/diagnosis , Nephritis, Hereditary/pathology , Pedigree , Phenotype , Polycystic Kidney Diseases/genetics , Polycystic Kidney Diseases/diagnosis , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/diagnosisABSTRACT
Alport syndrome and autosomal dominant polycystic kidney disease are monogenic causes of chronic kidney disease and end-stage kidney failure. We present a case of a man in his 60s with progressive chronic kidney disease, bilateral sensorineural hearing loss and multiple renal cysts. Genetic analysis revealed a heterozygous variant in COL4A3 (linked to Alport syndrome) and in the GANAB gene (associated with a milder form of autosomal dominant polycystic kidney disease). Although each variant confers a mild risk of developing end-stage kidney disease, the patient presented a pronounced and accelerated progression of chronic kidney disease, which goes beyond what would be predicted by adding up their individual effects. This suggests a potential synergic effect of both variants, which warrants further investigation.
Subject(s)
Collagen Type IV , Nephritis, Hereditary , Polycystic Kidney, Autosomal Dominant , Humans , Nephritis, Hereditary/genetics , Nephritis, Hereditary/complications , Nephritis, Hereditary/diagnosis , Male , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/complications , Collagen Type IV/genetics , Middle Aged , Autoantigens/genetics , Disease Progression , Kidney Failure, Chronic/genetics , Kidney Failure, Chronic/etiology , Hearing Loss, Sensorineural/genetics , Hearing Loss, Sensorineural/diagnosisABSTRACT
WT 9-12 is one of the cell lines commonly used for autosomal dominant polycystic kidney disease (ADPKD) studies. Previous studies had described the PKD gene mutations and polycystin expression in WT 9-12. Nonetheless, the mutations occurring in other ADPKD-associated genes have not been investigated. This study aims to revisit these mutations and protein profile of WT 9-12. Whole genome sequencing verified the presence of truncation mutation at amino acid 2556 (Q2556X) in PKD1 gene of WT 9-12. Besides, those variations with high impacts included single nucleotide polymorphisms (rs8054182, rs117006360, and rs12925771) and insertions and deletions (InDels) (rs145602984 and rs55980345) in PKD1L2; InDel (rs1296698195) in PKD1L3; and copy number variations in GANAB. Protein profiles generated from the total proteins of WT 9-12 and HK-2 cells were compared using isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Polycystin-1 was absent in WT 9-12. The gene ontology enrichment and reactome pathway analyses revealed that the upregulated and downregulated proteins of WT 9-12 relative to HK-2 cell line leaded to signaling pathways related to immune response and amino acid metabolism, respectively. The ADPKD-related mutations and signaling pathways associated with differentially expressed proteins in WT 9-12 may help researchers in cell line selection for their studies.
Subject(s)
Mutation , Polycystic Kidney, Autosomal Dominant , TRPP Cation Channels , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/pathology , Humans , Cell Line , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Polymorphism, Single Nucleotide , DNA Copy Number VariationsABSTRACT
Alteration of DNA methylation leads to diverse diseases, and the dynamic changes of DNA methylation (DNAm) on sets of CpG dinucleotides in mammalian genomes are termed "DNAm age" and "epigenetic clocks" that can predict chronological age. However, whether and how dysregulation of DNA methylation promotes cyst progression and epigenetic age acceleration in autosomal dominant polycystic kidney disease (ADPKD) remains elusive. Here, we show that DNA methyltransferase 1 (DNMT1) is upregulated in cystic kidney epithelial cells and tissues and that knockout of Dnmt1 and targeting DNMT1 with hydralazine, a safe demethylating agent, delays cyst growth in Pkd1 mutant kidneys and extends life span of Pkd1 conditional knockout mice. With methyl-CpG binding domain (MBD) protein-enriched genome sequencing (MBD-seq), DNMT1 chromatin immunoprecipitation (ChIP)-sequencing and RNA-sequencing analysis, we identified two novel DNMT1 targets, PTPRM and PTPN22 (members of the protein tyrosine phosphatase family). PTPRM and PTPN22 function as mediators of DNMT1 and the phosphorylation and activation of PKD-associated signaling pathways, including ERK, mTOR and STAT3. With whole-genome bisulfide sequencing in kidneys of patients with ADPKD versus normal individuals, we found that the methylation of epigenetic clock-associated genes was dysregulated, supporting that epigenetic age is accelerated in the kidneys of patients with ADPKD. Furthermore, five epigenetic clock-associated genes, including Hsd17b14, Itpkb, Mbnl1, Rassf5 and Plk2, were identified. Thus, the diverse biological roles of these five genes suggest that their methylation status may not only predict epigenetic age acceleration but also contribute to disease progression in ADPKD.
Subject(s)
DNA (Cytosine-5-)-Methyltransferase 1 , DNA Methylation , Epigenesis, Genetic , Mice, Knockout , Polycystic Kidney, Autosomal Dominant , TRPP Cation Channels , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/enzymology , DNA (Cytosine-5-)-Methyltransferase 1/genetics , DNA (Cytosine-5-)-Methyltransferase 1/metabolism , Animals , Humans , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Mice , Signal Transduction , Disease Models, Animal , Male , Disease Progression , Kidney/pathology , Kidney/metabolismABSTRACT
Nephron progenitor cells (NPCs) self-renew and differentiate into nephrons, the functional units of the kidney. Here, manipulation of p38 and YAP activity allowed for long-term clonal expansion of primary mouse and human NPCs and induced NPCs (iNPCs) from human pluripotent stem cells (hPSCs). Molecular analyses demonstrated that cultured iNPCs closely resemble primary human NPCs. iNPCs generated nephron organoids with minimal off-target cell types and enhanced maturation of podocytes relative to published human kidney organoid protocols. Surprisingly, the NPC culture medium uncovered plasticity in human podocyte programs, enabling podocyte reprogramming to an NPC-like state. Scalability and ease of genome editing facilitated genome-wide CRISPR screening in NPC culture, uncovering genes associated with kidney development and disease. Further, NPC-directed modeling of autosomal-dominant polycystic kidney disease (ADPKD) identified a small-molecule inhibitor of cystogenesis. These findings highlight a broad application for the reported iNPC platform in the study of kidney development, disease, plasticity, and regeneration.
Subject(s)
Nephrons , Organoids , Animals , Organoids/cytology , Organoids/metabolism , Humans , Nephrons/cytology , Mice , Cell Differentiation , Induced Pluripotent Stem Cells/metabolism , Induced Pluripotent Stem Cells/cytology , Podocytes/metabolism , Podocytes/cytology , Kidney/pathology , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , Models, Biological , Gene EditingABSTRACT
Mechanical loading is required for bone homeostasis, but the underlying mechanism is still unclear. Our previous studies revealed that the mechanical protein polycystin-1 (PC1, encoded by Pkd1) is critical for bone formation. However, the role of PC1 in bone resorption is unknown. Here, we found that PC1 directly regulates osteoclastogenesis and bone resorption. The conditional deletion of Pkd1 in the osteoclast lineage resulted in a reduced number of osteoclasts, decreased bone resorption, and increased bone mass. A cohort study of 32,500 patients further revealed that autosomal dominant polycystic kidney disease, which is mainly caused by loss-of-function mutation of the PKD1 gene, is associated with a lower risk of hip fracture than those with other chronic kidney diseases. Moreover, mice with osteoclast-specific knockout of Pkd1 showed complete resistance to unloading-induced bone loss. A mechanistic study revealed that PC1 facilitated TAZ nuclear translocation via the C-terminal tail-TAZ complex and that conditional deletion of Taz in the osteoclast lineage resulted in reduced osteoclastogenesis and increased bone mass. Pharmacological regulation of the PC1-TAZ axis alleviated unloading- and estrogen deficiency- induced bone loss. Thus, the PC1-TAZ axis may be a potential therapeutic target for osteoclast-related osteoporosis.
Subject(s)
Bone Resorption , Mice, Knockout , Osteoclasts , Osteogenesis , TRPP Cation Channels , Animals , TRPP Cation Channels/genetics , TRPP Cation Channels/metabolism , Bone Resorption/metabolism , Bone Resorption/genetics , Bone Resorption/pathology , Osteoclasts/metabolism , Mice , Humans , Osteoporosis/genetics , Osteoporosis/metabolism , Osteoporosis/pathology , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/pathology , Male , Female , Adaptor Proteins, Signal TransducingABSTRACT
Mouse models of autosomal dominant polycystic kidney disease (ADPKD) show that intact primary cilia are required for cyst growth following the inactivation of polycystin-1. The signaling pathways underlying this process, termed cilia-dependent cyst activation (CDCA), remain unknown. Using translating ribosome affinity purification RNASeq on mouse kidneys with polycystin-1 and cilia inactivation before cyst formation, we identify the differential 'CDCA pattern' translatome specifically dysregulated in kidney tubule cells destined to form cysts. From this, Glis2 emerges as a candidate functional effector of polycystin signaling and CDCA. In vitro changes in Glis2 expression mirror the polycystin- and cilia-dependent changes observed in kidney tissue, validating Glis2 as a cell culture-based indicator of polycystin function related to cyst formation. Inactivation of Glis2 suppresses polycystic kidney disease in mouse models of ADPKD, and pharmacological targeting of Glis2 with antisense oligonucleotides slows disease progression. Glis2 transcript and protein is a functional target of CDCA and a potential therapeutic target for treating ADPKD.
Subject(s)
Cilia , Disease Models, Animal , Polycystic Kidney, Autosomal Dominant , Signal Transduction , TRPP Cation Channels , Animals , Humans , Male , Mice , Cilia/metabolism , Kidney/metabolism , Kidney/pathology , Mice, Inbred C57BL , Mice, Knockout , Oligonucleotides, Antisense/pharmacology , Polycystic Kidney Diseases/metabolism , Polycystic Kidney Diseases/genetics , Polycystic Kidney Diseases/pathology , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/drug therapy , TRPP Cation Channels/metabolism , TRPP Cation Channels/geneticsABSTRACT
INTRODUCTION: Autosomal Dominant Polycystic Kidney Disease (ADPKD) is the most common inherited kidney condition caused by a single-gene mutation. It leads patients to kidney failure in more than 50% of cases by the age of 60, and, given the dominant inheritance, this disease is present in the family history in more than 90% of cases. AREAS COVERED: This review aims to analyze the set of preclinical and early-phase studies to provide a general view of the current progress on ADPKD therapeutic options. Articles from PubMed and the current status of the trials listed in clinicaltrials.gov were examined for the review. EXPERT OPINION: Many potential therapeutic targets are currently under study for the treatment of ADPKD. A few drugs have reached the clinical phase, while many are currently still in the preclinical phase. Organoids could be a novel approach to the study of drugs in this phase. Other than pharmacological options, very important developing approaches are represented by gene therapy and the use of MiRNA inhibitors.
Subject(s)
Drug Development , Drugs, Investigational , Genetic Therapy , Polycystic Kidney, Autosomal Dominant , Humans , Polycystic Kidney, Autosomal Dominant/drug therapy , Polycystic Kidney, Autosomal Dominant/genetics , Polycystic Kidney, Autosomal Dominant/physiopathology , Polycystic Kidney, Autosomal Dominant/pathology , Animals , Drugs, Investigational/pharmacology , Genetic Therapy/methods , Mutation , MicroRNAs/geneticsABSTRACT
Autosomal dominant polycystic kidney disease (ADPKD) is a common monogenic kidney disease. Emerging research indicates that the Notch signaling pathway plays an indispensable role in the pathogenesis of numerous kidney diseases, including ADPKD. Herein, we identified that Notch3 but not other Notch receptors was overexpressed in renal tissues from mice with ADPKD and ADPKD patients. Inhibiting Notch3 with γ-secretase inhibitors, which block a proteolytic cleavage required for Notch3 activation, or shRNA knockdown of Notch3 significantly delayed renal cyst growth in vitro and in vivo. Subsequent mechanistic study elucidated that the cleaved intracellular domain of Notch3 (N3ICD) and Hes1 could bind to the PTEN promoter, leading to transcriptional inhibition of PTEN. This further activated the downstream PI3K-AKT-mTOR pathway and promoted renal epithelial cell proliferation. Overall, Notch3 was identified as a novel contributor to renal epithelial cell proliferation and cystogenesis in ADPKD. We envision that Notch3 represents a promising target for ADPKD treatment.
Subject(s)
Cell Proliferation , Polycystic Kidney, Autosomal Dominant , Receptor, Notch3 , Animals , Receptor, Notch3/metabolism , Receptor, Notch3/genetics , Cell Proliferation/drug effects , Cell Proliferation/physiology , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/drug therapy , Polycystic Kidney, Autosomal Dominant/pathology , Polycystic Kidney, Autosomal Dominant/genetics , Mice , Humans , Mice, Inbred C57BL , Male , Kidney/metabolism , Kidney/pathology , Kidney/drug effectsABSTRACT
Autosomal dominant polycystic kidney disease is a genetic kidney disease caused by mutations in the genes PKD1 or PKD2. Its course is characterized by the formation of progressively enlarged cysts in the renal tubules bilaterally. The basic genetic explanation for autosomal dominant polycystic kidney disease is the double-hit theory, and many of its mechanistic issues can be explained by the cilia doctrine. However, the precise molecular mechanisms underpinning this condition's occurrence are still not completely understood. Experimental evidence suggests that aquaporins, a class of transmembrane channel proteins, including aquaporin-1, aquaporin-2, aquaporin-3, and aquaporin-11, are involved in the mechanism of autosomal dominant polycystic kidney disease. Aquaporins are either a potential new target for the treatment of autosomal dominant polycystic kidney disease, and further study into the physiopathological role of aquaporins in autosomal dominant polycystic kidney disease will assist to clarify the disease's pathophysiology and increase the pool of potential treatment options. We primarily cover pertinent findings on aquaporins in autosomal dominant polycystic kidney disease in this review.
Subject(s)
Aquaporins , Polycystic Kidney, Autosomal Dominant , Humans , Polycystic Kidney, Autosomal Dominant/metabolism , Polycystic Kidney, Autosomal Dominant/genetics , Aquaporins/metabolism , Aquaporins/genetics , Animals , MutationABSTRACT
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common monogenic disorder characterized by renal cysts and progressive renal failure. In kidney diseases, adipose tissue undergoes functional changes that have been associated with increased inflammation and insulin resistance mediated by release of adipokines. Adiponectin is involved in various cellular processes, such as energy and inflammatory and oxidative processes. However, it remains to be determined whether adiponectin is involved in the concomitant metabolic dysfunctions present in PKD. In this scenario, we aimed to analyze: (a) PPARγ, ADIPOQ, ADIPOR1 and ADIPOR2 gene variations in 92 ADPKD patients through PCR-Sanger sequencing; and (b) adiponectin levels and its oligomerization state by ELISA and Western Blot. Our results indicated that: (a) 14 patients carried the PPARγ SNP, 29 patients carried the ADIPOQ SNP rs1501299, and 25 patients carried the analyzed ADIPOR1 SNPs. Finally, 82 patients carried ADIPOR2 SNPs; and (b) Adiponectin is statistically lower in ADPKD patients compared to controls, and further statistically lower in ESRD than in non-ESRD patients. An inverse relationship between adiponectin and albumin and between adiponectin and creatinine and a direct relationship between adiponectin and eGFR were found. Interestingly, significantly lower levels of adiponectin were found in patients bearing the ADIPOQ rs1501299 SNP and associated with low levels of eGFR. In conclusion, adiponectin levels and the presence of ADIPOQ rs1501299 genotype are significantly associated with a worse ADPKD phenotype, indicating that both could potentially provide important insights into the disease. Further studies are warranted to understand the pathophysiological role of adiponectin in ADPKD patients.