Zhang et al. report that disruption of the CK2/PIAS1/SPOP signaling axis, by SPOP mutations or pharmacological blockade, increases the efficacy of the PARP inhibitor olaparib in prostate cancer models. The cover art represents DNA damage induced by PARP inhibitors, with SUMOylated SPOP promoting DNA damage repair. Cover art was generated with the Dreamina AI tool.
Pharmacological rescue of F508del-CFTR by the triple combination CFTR modulator therapy elexacaftor/tezacaftor/ivacaftor (ETI) leads to unprecedented clinical benefits in patients with cystic fibrosis (CF), however, previous studies in CF primary human airway epithelial cultures demonstrated that chronic treatment with the potentiator ivacaftor can render the F508del protein unstable thus limiting restoration of CFTR chloride channel function. However, quantitative studies of this unwanted effect of ivacaftor on F508del channel function including dependency on cell culture conditions remain limited and the impact of chronic ivacaftor exposure on restoration of mucociliary clearance that is impaired in patients with CF has not been studied. In patient-derived primary nasal epithelial cultures, we found that different culture conditions (UNC-ALI medium vs. PneumaCult medium) have profound effects on ETI-mediated restoration of F508del-CFTR function. Chronic treatment with ivacaftor as part of ETI triple therapy limited the rescue of F508del-CFTR chloride channel function when CF nasal epithelial cultures were grown in UNC-ALI medium, but not in PneumaCult medium. In PneumaCult medium, both chronic and acute addition of ivacaftor as part of ETI treatment led to constitutive CFTR-mediated chloride secretion in the absence of exogenous cAMP-dependent stimulation. This constitutive CFTR-mediated chloride secretion was essential to improve viscoelastic properties of the mucus layer and to restore mucociliary transport on CF nasal epithelial cultures. Furthermore, nasal potential difference measurements in patients with CF showed that ETI restored constitutive F508del-CFTR activity in vivo. These results demonstrate that ivacaftor as a component of ETI therapy is essential to restore mucociliary clearance and suggest that this effect is facilitated by its constitutive activation of F508del channels following their folding-correction in patients with CF.
Anita Balázs, Tihomir Rubil, Christine K. Wong, Jasmin Berger, Marika Drescher, Kathrin Seidel, Mirjam Stahl, Simon Y. Graeber, Marcus A. Mall
Mutations in genome maintenance factors drive sporadic and hereditary breast cancers. Here, we searched for potential drivers based on germline DNA analysis from a cohort consisting of early-onset breast cancer patients negative for BRCA1/BRCA2 mutations. This revealed candidate genes that subsequently were subjected to RNAi-based phenotype screens to reveal genome integrity impacts. We identified several genes with functional roles in genome maintenance, including Glucose-6-Phosphatase Catalytic Subunit 3 (G6PC3), SMC4, and CCDC108. Notably, G6PC3-deficient cells exhibited increased levels of γH2AX and micronuclei formation, along with defects in homologous recombination (HR) repair. Consistent with these observations, G6PC3 was required for the efficient recruitment of BRCA1 to sites of DNA double-strand breaks (DSBs). RNA sequencing analysis revealed that G6PC3 promotes the expression of multiple homologous recombination repair genes, including BRCA1. Through CRISPR-Select functional-genetic phenotype analysis of G6PC3 germline mutations, we identified two germline G6PC3 variants displaying partial loss-of-function. Furthermore, our study demonstrated that G6pc3 deficiency accelerates mammary tumor formation induced by Trp53 loss in mice. In conclusion, our cohort-based functional analysis has unveiled genome maintenance factors and identified G6PC3 as a potential candidate tumor suppressor in breast cancer.
Xin Li, Maria Rossing, Ana Moisés da Silva, Muthiah Bose, Thorkell Gudjónsson, Jan Benada, Jayashree Thatte, Jens Vilstrup Johansen, Judit Börcsök, Hanneke van der Gulden, Ji-Ying Song, Renée Menezes, Asma Tajik, Lucía Sena, Zoltan Szallasi, Morten Frödin, Jos Jonkers, Finn Cilius Nielsen, Claus Storgaard Sørensen
Pf bacteriophages, lysogenic viruses that infect Pseudomonas aeruginosa (Pa), are implicated in the pathogenesis of chronic Pa infections; phage-infected (Pf+) strains are known to predominate in people with cystic fibrosis (pwCF) who are older and have more severe disease. However, the transmission patterns of Pf underlying the progressive dominance of Pf+ strains are unclear. In particular, it is unknown whether phage transmission commonly occurs horizontally between bacteria via viral particles within the airway or if Pf+ bacteria are mostly acquired via de novo Pseudomonas infections. Here, we studied Pa genomic sequences from 3 patient cohorts totaling 662 clinical isolates from 105 pwCF. We identified Pf+ isolates and analyzed transmission patterns of Pf within patients between genetically similar groups of bacteria called “clone types”. We found that Pf was predominantly passed down vertically within Pa clone types and rarely via horizontal transfer between clone types within the airway. Conversely, we found extensive evidence of Pa de novo infection by a new, genetically distinct Pf+ Pa. Finally, we observed that clinical isolates showed reduced activity of the type IV pilus and reduced susceptibility to Pf in vitro. These results cast new light on the transmission of virulence-associated phages in the clinical setting.
Julie D. Pourtois, Naomi L. Haddock, Aditi Gupta, Arya Khosravi, Hunter A. Martinez, Amelia K. Schmidt, Prema S. Prakash, Ronit Jain, Piper Fleming, Tony H. Chang, Carlos Milla, Patrick R. Secor, Giulio A. De Leo, Paul L. Bollyky, Elizabeth B. Burgener
Oxidative stress driven by malfunctioning respiratory complex I (RC-I) is a crucial pathogenic factor in liver ischemia/reperfusion (I/R) injury. This study investigates the role of alkaline ceramidase 3 (ACER3) and its unsaturated long-chain ceramide (CER) substrates in regulating liver I/R injury through RC-I. Our findings demonstrated that I/R upregulated ACER3/Acer3 and decreased unsaturated long-chain CER levels in human and mouse livers. Both global and hepatocyte-specific Acer3 ablation, as well as treatment with CER(d18:1/18:1), led to a significant increase of CER(d18:1/18:1) levels in the liver, which mitigated the I/R-induced hepatocyte damage and inflammation in mice. Mechanistically, Acer3 modulated CER(d18:1/18:1) levels in mitochondria-associated membranes and endoplasmic reticulum (ER), thereby influencing the transport of CER(d18:1/18:1) from ER to mitochondria. Acer3 ablation and CER(d18:1/18:1) treatment elevated CER(d18:1/18:1) in mitochondria, where CER(d18:1/18:1) bound to the RC-I subunit Ndufa6 to inactivate RC-I and reduced reactive oxygen species production in the I/R-injured mouse liver. These findings underscore the role of CER(d18:1/18:1)-Ndufa6 interaction in suppressing RC-I-mediated oxidative-stress-driven pathogenesis in liver I/R Injury.
Kai Wang, Leyi Liao, Hanbiao Liang, Pengxiang Huang, Qingping Li, Baoxiong Zhuang, Chen Xie, Xiangyue Mo, Xuesong Deng, Jieyuan Li, Yang Lei, Minghui Zeng, Cungui Mao, Ruijuan Xu, Cuiting Liu, Xianqiu Wu, Jie Zhou, Biao Wang, Yiyi Li, Chuanjiang Li
We developed a 29-color spectral cytometry panel to enhance nonhuman primate (NHP) models for cross-reactive immunophenotyping. This panel is suitable for biosafety level 4 (BSL-4) viruses and can be used with both human and NHP samples in BSL-2 research settings. Tissues from humans, rhesus monkeys (RhMs), crab-eating macaques (CEMs), and green monkeys (GMs) were stained with a 29-color immunophenotyping panel requiring only two clone substitutions. Comparable staining was observed for all samples. Unbiased analysis showed acceptable overlap in T-cell phenotypes across samples, with differences in human and NHP B cells and granulocytes. In CEMs, most circulating CD8+ T cells were from effector memory cells, with significantly higher levels than in humans (p<0.0001), RhMs (p<0.05), and GMs (p<0.01). Analysis of samples from various anatomical sites revealed distinct location-specific phenotypes. In Nipah-virus-exposed animals, splenocytes showed a substantial increase in IgM+ B cells (p<0.0001) and a reduction in effector memory CD8+ T cells (p<0.0001) compared to unexposed controls. Lymph nodes from Ebola-virus-exposed animals showed a loss of CXCR3+CD8+ T cells vs unexposed controls. This panel may guide the development of additional multi-color panels in preclinical and clinical settings and potentially increase understanding of the pathogenesis of diseases caused by emerging and re-emerging viruses.
Andrew P. Platt, Bobbi Barr, Anthony Marketon, Rebecca Bernbaum, Deja F.P. Rivera, Vincent J. Munster, Daniel S. Chertow, Michael R. Holbrook, Scott M. Anthony, Bapi Pahar
In this episode, Davide Croci, Sandra van Wilpe, and Niven Mehra explain that their manuscript predicts clinical benefit to immunotherapy by analyzing combined biomarkers from circulating tumor DNA and immune cell gene expression data in blood...