Autosomal dominant polycystic kidney disease (ADPKD) is one of the most prevalent genetic diseases affecting the kidneys. A genetically specific mutation model is required to comprehend its pathophysiology and to develop a drug treatment. In this study, we successfully developed human induced pluripotent stem cells (hiPSCs) named MUi027-A from skin fibroblasts of a patient diagnosed with ADPKD and carrying the PKD1 frameshift mutation (c.7946_7947delCT). MUi027-A cells showed the same genetic fingerprints as the parental cells, including the presence of the PKD1 mutation. MUi027-A hiPSCs displayed embryonic stem cell-like characteristics with the capability of differentiating into the three germ layers. Upon directed differentiation, MUi027-A hiPSCs could be differentiated into tubular organoids with the expression of renal cell markers. Furthermore, we compared the efficiency of cyst formation in two human iPSC lines with different PKD1 mutations. When cyst formation was induced by either forskolin or blebbistatin, MUi027-A hiPSC-derived kidney organoids displayed higher frequencies of cyst formation when compared to organoids generated from an iPSC cell line with non-truncating PKD1 mutation genotype (c.5878C > T), suggesting the presence of physiological differences in the mechanism of cyst formation between different PKD1 mutants. Overall, we generated and characterized a novel human iPSC line with a specific PKD mutation and demonstrated its potential as a disease model to study the pathophysiology of genetic determinants in the development of ADPKD disease.

Background: Mature lysostaphin (~28-kDa Lss) from Staphylococcus simulans proves effective in killing methicillin-resistant Staphylococcus aureus (MRSA) which is endemic in hospitals worldwide. Lss is Zn²⁺-dependent endopeptidase, but its bacteriolytic activity could be affected by exogenously added Zn²⁺.Objective: To gain greater insights into structural and functional impacts of Zn²⁺and Ni²⁺on Lss-induced bioactivity.Methods: Lss purified via immobilized metal ion-affinity chromatography was assessed for bioactivity using turbidity reduction assays. Conformational change of metal ion-treated Lss was examined by circular dichroism and intrinsic fluorescence spectroscopy. Co-sedimentation assay was performed to study interactions between Zn²⁺-treated Lss and S. aureus peptidoglycans. Metal ionbinding prediction and intermolecular docking were used to locate an extraneous Zn²⁺-binding site.Results: A drastic decrease in Lss bioactivity against S. aureus and MRSA was revealed only when treated with Zn²⁺, but not Ni²⁺, albeit no negative effect of diethyldithiocarbamate—Zn²⁺-chelator on Lss-induced bioactivity. No severe conformational change was observed for Lss incubated with exogenous Zn²⁺or Ni²⁺. Lss pre-treated with Zn²⁺efficiently bound to S. aureus cell-wall peptidoglycans, suggesting non-interfering effect of exogenous metal ions on cell-wall targeting (CWT) activity. In silico analysis revealed that exogenous Zn²⁺, but not Ni²⁺, preferably interacted with a potential extraneous Zn²⁺-binding site (His253, Glu318 and His323) placed near the Zn²⁺-coordinating Lssactive site within the catalytic (CAT) domain.Conclusion: Our present data signify the adverse influence of exogenous Zn²⁺ions on Lss-induced staphylolytic activity through the exclusive presence within the CAT domain of an extraneous inhibitory Zn²⁺-binding site, without affecting the CWT activity.

Establishing a drug-screening platform is critical for the discovery of potential antiviral agents against SARS-CoV-2. In this study, we developed a platform based on human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) to investigate SARS-CoV-2 infectivity, with the aim of evaluating potential antiviral agents for anti-SARS-CoV-2 activity and cardiotoxicity. Cultured myocytes of iPSC-CMs and immortalized human cardiomyocyte cell line (AC-16) were primarily characterized for the expression of cardiac markers and host receptors of SARS-CoV-2. An infectivity model for the wild-type SARS-CoV-2 strain was then established. Infection modeling involved inoculating cells with SARS-CoV-2 at varying multiplicities of infection (MOIs) and then quantifying infection using immunofluorescence and plaque assays. Only iPSC-CMs, not AC16 cells, expressed angiotensin-converting enzyme 2 (ACE-2), and quantitative assays confirmed the dose-dependent infection of iPSC-CMs by SARS-CoV-2, unlike the uninfectable AC16 cells lacking the expression of ACE2. Cytotoxicity was evaluated using MTT assays across a concentration range. An assessment of the plant-derived compound panduratin A (panA) showed cytotoxicity at higher doses (50% cytotoxic concentration (CC₅₀) 10.09 μM) but promising antiviral activity against SARS-CoV-2 (50% inhibition concentration (IC₅₀) 0.8–1.6 μM), suppressing infection at concentrations 10 times lower than its CC₅₀. Plaque assays also showed decreased viral production following panA treatment. Overall, by modeling cardiac-specific infectivity, this iPSC-cardiomyocyte platform enables the reliable quantitative screening of compound cytotoxicity alongside antiviral efficacy. By combining disease pathogenesis and pharmacology, this system can facilitate the evaluation of potential novel therapeutics, such as panA, for drug discovery applications.