Biology subjects

Adamson, R.

Publications and source records attributed to Adamson, R..

3 recordsLinked to original sources

bioRxiv2026

Structural Basis for Inhibition of Human Anion Transporter SLC26A6/PAT-1

PAT-1, encoded by the gene SLC26A6, is an exchanger of small organic and inorganic anions including oxalate and chloride in the kidney and the intestines. PAT-1 dysfunction is implicated in nephrolithiasis and hyperoxaluria, and its modulation is a potential therapeutic strategy to treat cystic fibrosis. PAT-1 has two small molecule inhibitors: DIDS, a non-specific anion exchanger inhibitor; and PAT1inh-B01 which is highly specific to PAT-1. In this study, we report high-resolution cryo-electron microscopy structures of the human PAT-1 homodimer in complex with these inhibitors to reveal their different inhibition mechanisms. These structures also uncover the complex interactions between the transmembrane, STAS and N-terminal domains, with implications on its ion exchange function. Hence, this study provides mechanistic insight into PAT-1 molecular function and inhibition, and contributes to our understanding of SLC26 transport mechanisms.

biochemistry↗

bioRxiv2019

Tetraploidy in rodent cardiac stem cells confers enhanced biological properties

Ploidy for cardiomyocytes is well described but remains obscure in cardiac interstitial cells (CICs). Ploidy of c-kit+CICs were assessed using a combination of confocal, karyotypic, and flow cytometric assessments coupled with molecular and bioinformatic analyses. Fundamental differences were found between cultured rodent (rat, mouse) c-kit+CICs possessing mononuclear tetraploid (4n) content versus large mammal (human, swine) with mononuclear diploid (2n) content. In-situ analysis, confirmed with fresh isolates, revealed diploid content in c-kit+CICs from human and a mixture of diploid and tetraploid nuclei in mouse. Molecular assessment of the p53 signaling pathway provides a plausible explanation for escape from replicative senescence in rodent but not human ckit+CICs. Single cell transcriptional profiling reveals distinctions between diploid versus tetraploid populations in mouse ckit+CICs, alluding to functional divergences. Collectively, these data reveal fundamental species-specific biological differences in c-kit+CICs that could account for challenges in extrapolation of myocardial preclinical studies from rodent to large animal models.

cell biology↗

bioRxiv2019

Safety profiling of genetically engineered Pim-1 kinase overexpression for oncogenicity risk in human c-kit+ cardiac interstitial cells

Advanced approaches to stem cell-based therapies is necessary for myocardial regenerative therapy because treatments have yielded modest results in the clinic. Our group previously demonstrated genetic modification of cardiac stem cells with Pim-1 kinase overexpression rejuvenated aged cells and potentiated myocardial repair. Despite these encouraging findings, concerns were raised regarding oncogenic risk associated with Pim-1 kinase overexpression. Testing of these c-kit+ cardiac interstitial cells (cCICs), derived from heart failure patient samples, overexpressing Pim-1 (cCICs-Pim-1) for indices of oncogenic risk was assessed by soft agar colony formation, micronucleation, gamma-Histone 2AX foci, and transcriptome profiling. Collectively, findings demonstrate comparable phenotypic and biological properties of cCICsPim-1 compared to baseline control cCICs with no evidence for oncogenic phenotype. Using a highly-selective and continuous sensor for quantitative assessment of PIM1 kinase activity, a 7-fold increase in cCICs-Pim-1 versus cCICs resulted. Kinase activity was elevated in IKKs, AKT/SGK, CDK1-3, p38, and ERK1/2 in addition to Pim-1, correlating Pim-1 overexpression to contribute to Pim-1-mediated effects. Enhancement of cellular survival, proliferation, and other beneficial properties to augment stem cell-mediated repair without oncogenic risk is a feasible, logical, and safe approach to improve efficacy and overcome current limitations inherent to cellular adoptive transfer therapeutic interventions.

cell biology↗