TTRV30M oligomeric aggregates inhibit proliferation of renal progenitor cells but maintain their capacity to differentiate into podocytes in vitro

Publicado em: The Proceedings of the XIIIth International Symposium on Amyloidosis, May 6-10, 2012, Groningen, The NetherlandsIn Familial Amyloidotic Polyneuropathy, the amyloid deposition of mutant transthyretin TTR V30M can lead to renal complications. An unexplored mechanism is the toxicity of oligomeric TTR aggregates. A subset of renal progenitor cells (RPC) in the adult human kidney can induce regeneration of podocytes and tubular structures of the nephron, which can be critical for preventing irreversible renal failure. We assessed whether RPC are vulnerable, in vitro, to TTRV30M oligomers. RPC proliferation was reduced by 16.3±9.7% and 32.6±6.3% after 48 and 72 hours, respectively, in the presence of the oligomers. However, oligomers did not induce apoptosis or alterations in cell cycle to any significant extent, and did not influence RPC differentiation into podocytes. From this first attempt, we can say that TTRV30M oligomers inhibit RPC proliferation but do not influence their capacity to differentiate into mature podocytes, and thus should not compromise tissue regeneration.FC

Acute kidney injury promotes development of papillary renal cell adenoma and carcinoma from renal progenitor cells.

Acute tissue injury causes DNA damage and repair processes involving increased cell mitosis and polyploidization, leading to cell function alterations that may potentially drive cancer development. Here, we show that acute kidney injury (AKI) increased the risk for papillary renal cell carcinoma (pRCC) development and tumor relapse in humans as confirmed by data collected from several single-center and multicentric studies. Lineage tracing of tubular epithelial cells (TECs) after AKI induction and long-term follow-up in mice showed time-dependent onset of clonal papillary tumors in an adenoma-carcinoma sequence. Among AKI-related pathways, NOTCH1 overexpression in human pRCC associated with worse outcome and was specific for type 2 pRCC. Mice overexpressing NOTCH1 in TECs developed papillary adenomas and type 2 pRCCs, and AKI accelerated this process. Lineage tracing in mice identified single renal progenitors as the cell of origin of papillary tumors. Single-cell RNA sequencing showed that human renal progenitor transcriptome showed similarities to PT1, the putative cell of origin of human pRCC. Furthermore, NOTCH1 overexpression in cultured human renal progenitor cells induced tumor-like 3D growth. Thus, AKI can drive tumorigenesis from local tissue progenitor cells. In particular, we find that AKI promotes the development of pRCC from single progenitors through a classical adenoma-carcinoma sequence

Urine-derived human renal progenitor cultures for modeling of genetic kidney disorders in subject studied by Next Generation Sequencing

The advent of high-throughput sequencing has fostered the identification of novel causative genes of kidney disorders, and has allowed the continuous discovery of genetic variants of unknown significance often raising the problem of the functional testing of their pathogenic role. However, emerging evidence implicates that influence of the genomic background of the patient, as well as epigenetic modifications are critical in determining the clinical phenotype. Renal progenitor cell (RPC) cultures obtained from the affected patient may represent an ideal alternative for personalized disease modeling. Since loss of renal cells in urine naturally occurs in patients, urine may represent a potential RPC source. In this study, we selected and amplified RPC cultures from the urine of patients with renal disease, and we evaluated the possibility to use these cells for modeling of genetic kidney disorders. Urin-RPC were obtained from five children affected by Nephrotic Syndrome carrying mutations in genes encoding for podocyte cytoskeleton proteins, identified thought Next Generation Sequencing, as well as from children without genetic alterations (five). The first cells exhibited altered synthesis of mutated proteins, abnormal cytoskeleton structure and functional abnormalities; by contrast, the second ones showed normal phenotype, structure and function. The development of functional assays with Urin-RPC could serve as a fundamental step for rapid testing of putative pathogenic mutations. In particular, this tool can provide an essential support for the clinical diagnosis of nephrotic syndrome in patients carrying variants of uncertain significance and provide information to optimize an affected individual’s personalized medical care

URINE-DERIVED HUMAN RENAL PROGENITOR CULTURES FOR MODELING OF GENETIC KIDNEY DISORDERS

The development of functional assays with u-RPC obtained from patients with genetic kidney disorders could serve as a fundamental step for rapid testing of putative pathogenic mutations. In particular, this tool can provide an essential support for the clinical diagnosis of nephrotic syndrome in patients carrying variants of uncertain significance in podocyte genes. The results of this study demonstrate that u-RPC cultures represent an innovative research tool which provide information to optimize an affected individual’s personalized medical care