Biology subjects

Biggers, L.

Publications and source records attributed to Biggers, L..

3 recordsLinked to original sources

bioRxiv2025

Disruption of a six-nucleotide miRNA motif improves PKD1 dosage and ameliorates polycystic kidney disease

Disrupting microRNA interactions to restore protein expression from haploinsufficient genes offers a promising precision-therapy strategy for monogenic disorders. PKD1 heterozygosity underlies autosomal dominant polycystic kidney disease (ADPKD), a disorder affecting nearly 12 million people worldwide, where reduced PKD1 dosage drives progressive cyst formation and kidney failure. We previously identified a 55-bp cis-repressive element in the PKD1 3'UTR. Here, we define a six-nucleotide miR-17 seed match within this element that is sufficient to reproduce PKD1 repression. In vivo base substitution of this motif stabilizes Pkd1 mRNA and increases polycystin-1 (PC1) protein levels, producing a robust reduction in cyst growth and preservation of kidney function in mouse models. To therapeutically recapitulate this effect, we developed a steric-blocking oligonucleotide that occludes the motif, stabilizes PKD1 transcript levels, increases PC1 expression, and mitigates cyst-pathogenic events in both murine and patient-derived ADPKD cells. Together, these findings establish a minimal, targetable cis-regulatory motif and provide proof-of-concept for oligonucleotide-mediated PKD1 derepression, while offering a potentially generalizable strategy to restore other haploinsufficient genes.

genetics↗

bioRxiv2022

PKD1 and PKD2 mRNA cis-inhibition drives polycystic kidney disease progression

Autosomal dominant polycystic kidney disease (ADPKD), among the most common human genetic conditions and a frequent etiology of kidney failure, is primarily caused by heterozygous PKD1 mutations. Kidney cyst formation ensues when the PKD1 dosage falls below a critical threshold. However, no framework exists to harness the remaining allele or reverse PKD1 decline. Here, we show that mRNAs produced by the noninactivated PKD1 allele are cis-repressed via their 3-UTR miR-17 binding element. Eliminating this motif (Pkd1{Delta}17) improves mRNA stability, raises Polycystin-1 levels, and alleviates cyst growth in cellular, ex vivo, and mouse PKD models. Remarkably, Pkd2 is also autoinhibited via its 3-UTR miR-17 motif, and Pkd2{Delta}17-induced Polycystin-2 derepression partly compensates and retards cyst growth in Pkd1-mutant models. Moreover, acutely blocking Pkd1/2 cis-inhibition, including after cyst onset, attenuates murine PKD. Finally, PKD1{Delta}17 or PKD2{Delta}17 alleles revert cyst-pathogenic sequala in patient-derived primary ADPKD cultures. Thus, evading 3-UTR cis-interference and enhancing PKD1/2 mRNA translation is a potentially mutation-agnostic ADPKD-arresting approach.

genetics↗

bioRxiv2021

Enhancer and super-enhancer landscape in polycystic kidney disease

Widespread aberrant gene expression is pathological hallmark of polycystic kidney disease (PKD). Numerous pathogenic signaling cascades, including c-Myc, Fos, and Jun are transactivated. However, the underlying epigenetic regulators are poorly defined. Here we show that H3K27ac, a histone modification that marks active enhancers, is elevated in mouse and human ADPKD samples. Using comparative H3K27ac ChIP-Seq analysis, we mapped >16000 active intronic and intergenic enhancer elements in Pkd1-mutant mouse kidneys. We find that the cystic kidney epigenetic landscape resembles that of a developing kidney, and >90% of upregulated genes in Pkd1-mutant kidneys are co-housed with activated enhancers in the same topologically associated domains. Furthermore, we identify an evolutionarily-conserved enhancer cluster downstream of the c-Myc gene and super-enhancers flanking both Jun and Fos loci in mouse and human ADPKD models. Deleting these regulatory elements reduces c-Myc, Jun, or Fos abundance and suppresses proliferation and 3D cyst growth of Pkd1-mutant cells. Finally, inhibiting glycolysis and glutaminolysis or activating Ppara in Pkd1-mutant cells lowers global H3K27ac levels and on c-Myc enhancers. Thus, our work suggests that epigenetic rewiring mediates the transcriptomic dysregulation in PKD, and the regulatory elements can be targeted to slow cyst growth.

molecular biology↗