Genetics
Abstract
Human Caspase Recruitment Domain Containing Protein 9 (CARD9) deficiency predisposes to invasive fungal disease, particularly by Candida spp. Distinctly, CARD9-deficiency causes chronic central nervous system (CNS) candidiasis. Currently, no animal model recapitulates the chronicity of disease, precluding a better understanding of immunopathogenesis. We established a knock-in mouse homozygous for the recurring p.Y91H mutation (Y91HKI) and, in parallel to Card9-/- mice, titrated the intravenous fungal inoculum to the CARD9-genotype to develop a model of chronic invasive candidiasis. Strikingly, CARD9-deficient mice had predominantly CNS involvement, with neurological symptoms appearing late during infection and progressive brain fungal burden in the absence of fulminant sepsis, reflecting the human syndrome. Mononuclear cell aggregation at fungal lesions in the brain correlated with increased MHCII+Ly6C+ monocyte numbers at day 1 post-infection in WT and Y91HKI mice, but not in Card9-/- mice. At day 4 post-infection, neutrophils and additional Ly6C+ monocytes were recruited to the CARD9-deficient brain. As in humans, Y91HKI mutant mice demonstrated cerebral multinucleated giant cells and granulomata. Subtle immunologic differences between the hypomorphic (p.Y91H) and null mice were noted, perhaps explaining some of the variability seen in humans. Our work established a disease-recapitulating animal model to specifically decipher chronic CNS candidiasis due to CARD9 deficiency.
Authors
Marija Landekic, Isabelle Angers, Yongbiao Li, Marie-Christine Guiot, Marc-André Déry, Annie Beauchamp, Lucie Roussel, Annie Boisvert, Wen Bo Zhou, Christina Gavino, Julia Luo, Stéphane Bernier, Makayla Kazimerczak-Brunet, Yichun Sun, Brendan Snarr, Michail S. Lionakis, Robert T. Wheeler, Irah L. King, Salman Qureshi, Maziar Divangahi, Donald C. Vinh
Abstract
Many chemotherapeutic agents impair cancer growth by inducing DNA damage. The impact of these agents on mutagenesis in normal cells, including sperm, is largely unknown. Here, we applied high-fidelity duplex sequencing to 94 samples from 36 individuals exposed to diverse chemotherapies and 32 controls. We found that many of the sperm samples from men exposed to chemotherapy, the mutation burden was elevated as compared to controls and the expected burden based on trio studies, with one subject having >10-fold increase over expected for age. Saliva from this same individual also had a markedly higher mutation burden. We then validated this finding using other tissues, also finding an increased mutation burden in the blood and liver of many subjects exposed to chemotherapy as compared to unexposed controls. Similarly, mice treated with three cycles of cisplatin had an increased mutation burden in sperm but also in the liver, and hematopoietic progenitor cells. These results suggest an association between cancer therapies and mutation burden, with implications for counseling cancer patients considering banking sperm prior to therapy and for cancer survivors considering the tradeoffs of using banked sperm as compared to conceiving naturally.
Authors
Shany Picciotto, Camilo Arenas-Gallo, Amos Toren, Ruty Mehrian-Shai, Bryan Daly, Stephen Rhodes, Megan Prunty, Ruolin Liu, Anyull Bohorquez, Marta Grońska-Pęski, Shana Melanaphy, Pamela Callum, Emilie Lassen, Anne-Bine Skytte, Rebecca C. Obeng, Christopher Barbieri, Molly Gallogly, Brenda Cooper, Katherine Daunov, Lydia Beard, Koen Van-Besien, Joshua Halpern, Quintin Pan, Gilad D. Evrony, Viktor A. Adalsteinsson, Jonathan E. Shoag
Abstract
Inherited retinal degenerations (IRDs) are important causes of progressive, irreversible blindness. Hereditary macular diseases in particular are significant in their effect on the specialized, central cone photoreceptor-rich macula responsible for high resolution vision. Autosomal dominant Best vitelliform macular dystrophy (BVMD), caused by variants in the BEST1 gene, is one of the most common inherited macular dystrophies. Gene therapies have emerged as promising treatments for IRDs, but a lack of suitable animal models has hindered progress both in treatments and in understanding the mechanisms underlying macular diseases. Here, we report a Macaca fascicularis carrying a heterozygous potential pathogenic BEST1p.Q327E variant that disrupts the BEST1 ion channel by destabilizing the A195 helix, mirroring the structural perturbations seen in certain human pathological mutants. Longitudinal imaging over two years revealed progressive macular changes, including subfoveal cleft enlargement, lipid-rich deposit accumulation, retinal pigment epithelium (RPE) disruption, and central-to-peripheral photoreceptor degeneration, recapitulating early human BVMD pathology. Histopathology demonstrated diminished BEST1 expression, attenuation of the RPE-photoreceptor interface, and two distinct types of lipid deposits, including heretofore unappreciated cone mitochondrial-enriched lesions, highlighting selective cone mitochondria vulnerability. This first non-human primate model of inherited macular dystrophy links BEST1 mutations, mitochondrial dysfunction, and progressive macular degeneration, offering new insights into BVMD pathophysiology and highlighting its utility for studying disease progression and potential therapeutic interventions.
Authors
Wei Yi, Mingming Xu, Ying Xue, Yingxue Cao, Ziqi Yang, Lingli Zhou, Yang Zhou, Le Shi, Xiaomei Mai, Zehui Sun, Wenjie Qing, Yuying Li, Aolun Qing, Kaiwen Zhang, Lechun Ou, Shoudeng Chen, Elia J. Duh, Xialin Liu
Abstract
Non-small cell lung cancer (NSCLC) largely consists of lung squamous (LUSC) and lung adenocarcinoma (LUAD). Alterations in the TRP53 and PTEN tumor suppressors are common in both subtypes, but their relationship with SOX2 is poorly understood. We deleted Trp53 or Pten in a C57BL/6J-Sox2hi;Nkx2-1-/-;Lkb1-/- (SNL) genetic background and generated a highly metastatic LUSC cell line (LN2A; derived from a Sox2hi mouse model, followed by Trp53, Pten, and Cdkn2a deletion). Histologic and single-cell RNAseq analyses corroborated that SNL mice developed mixed tumors with both LUAD and LUSC histopathology while SNL-Trp53 and SNL-Pten mice developed LUAD and LN2A tumors retained LUSC morphology. Compared with SNL mice, additional loss of Trp53 or Pten resulted in significantly reduced survival, increased tumor burden and altered tumor mucin composition. We identified a sub-cluster of CD38+ tumor-associated inflammatory monocytes in the LN2A model that significantly enriched for activation of the classical and alternative complement pathways. Complement Factor B (CFB) is associated with poor survival in LUSC patients, and we observed the LN2A model had significantly improved survival on a Cfb-/- background. Our findings demonstrate a cooperative role of Trp53 and Pten tumor suppressors in Sox2-mediated NSCLC tumor progression, mucin production, and remodeling of the immune tumor microenvironment.
Authors
Nisitha Sengottuvel, Kristina M. Whately, Jennifer L Modliszewski, Rani S. Sellers, William D. Green, Weida Gong, Allison T. Woods, Eric W. Livingston, Katerina D. Fagan-Solis, Gabrielle Cannon, Lincy Edatt, Hong Yuan, Aaron C. Chack, Yazmin Sanchez, Katherine Zhou, Alyaa Dawoud, Jarred M. Green, Virginia Godfrey, J Justin Milner, Gaorav P. Gupta, Chad V. Pecot
Abstract
It is well documented that impaired DNA damage repair (DDR) induces genomic instability that can efficiently increase the sensitivity of prostate cancer (PCa) cells to PARP inhibitors; however, the underlying mechanism remains elusive. Here, we found profound genomic instability in PCa cells with SPOP gene mutations and confirmed the sensitivity of SPOP-mutated PCa cells to olaparib-induced apoptosis. Mechanistically, we identified olaparib-induced CK2-mediated phosphorylation of PIAS1-S468, which in turn mediated SUMOylation of SPOP, thus promoting its E3 ligase activity in the DDR. Moreover, an abnormal CK2/PIAS1/SPOP axis due to SPOP mutations or defects in CK2-mediated phosphorylation of PIAS1, as well as SPOP inhibitor treatment, led to impaired DDR, thus increasing olaparib-induced apoptosis of PCa cells and enhancing olaparib sensitivity in animal models and patient-derived organoids. This suggested that disruption of the CK2/PIAS1/SPOP signaling axis could serve as an indicator for targeted therapy of PCa using a PARP inhibitor.
Authors
Hui Zhang, Lili Kong, Jinhui Li, Zhihan Liu, Yiting Zhao, Xiuyi Lv, Liangpei Wu, Lin Chai, Hongjie You, Jiabei Jin, Xinyi Cao, Zhong Zheng, Yadong Liu, Zejun Yan, Xiaofeng Jin
Abstract
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.
Authors
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
Abstract
The notion of clonal cell populations in human atherosclerosis has been suggested but not demonstrated. Somatic mutations are used to define cellular clones in tumors. Here, we characterized the mutational landscape of human carotid plaques through whole-exome sequencing to explore the presence of clonal cell populations. Somatic mutations were identified in 12 of 13 investigated plaques, while no mutations were detected in 11 non-atherosclerotic arteries. Mutated clones often constituted over 10% of the sample cell population, with genes related to the contractile apparatus enriched for mutations. In CHIP (clonal hematopoiesis of indeterminate potential) carriers, hematopoietic clones had infiltrated the plaque tissue and constituted substantial fractions of the plaque cell population alongside locally expanded clones. Our findings establish somatic mutations as a common feature of human atherosclerosis and demonstrate the existence of mutated clones expanding locally, as well as CHIP clones invading from the circulation. While our data do not support plaque monoclonality, we observe a pattern suggesting the coexistence of multiple mutated clones of considerable size spanning different regions of plaques. Mutated clones are likely to be relevant to disease development, and somatic mutations will serve as a convenient tool to uncover novel pathological processes of atherosclerosis in future studies.
Authors
Lasse Bach Steffensen, Stephanie Kavan, Pia Søndergaard Jensen, Matilde Kvist Pedersen, Steffen Møller Bøttger, Martin J. Larsen, Maja Dembic, Otto Bergman, Ljubica Matic, Ulf Hedin, Lars vB Andersen, Jes Sanddal Lindholt, Kim Christian Houlind, Lars P. Riber, Mads Thomassen, Lars Melholt Rasmussen
Abstract
An estimated 5-10% of cancer results from an underlying genetic predisposition, yet for the majority of these cases the genes in question remain unknown, suggesting a critical need to identify new cancer predisposition genes. The protein phosphatase 2A (PP2A) family exists as a trimeric holoenzyme and is a vital negative regulator of multiple oncogenic pathways. PP2A inhibition by somatic mutation, loss of expression, and upregulation of its exogenous inhibitors in tumors has been well described. However, it remains unknown whether germline loss of any PP2A subunits results in a predisposition to cancer in humans. In this study, we identified nine cancer patients with germline loss-of-function (LOF) variants in PPP2R1B (Aβ), the beta isoform of the PP2A scaffold subunit. All four patients for whom documentation was available also had a family history of cancer, including multiple indicators of hereditary cancer. The most highly represented cancer among the Aβ germline patients was breast cancer. Overexpression of these mutant forms of Aβ resulted in truncated proteins that were rapidly turned over. Characterization of an additional missense germline Aβ variant, R233C, that is also recurrently mutated at the somatic level found that it disrupts PP2A catalytic subunit binding resulting in loss of phosphatase activity. An analysis of Aβ expression among multiple breast cancer cohorts revealed that somatic, heterozygous loss of Aβ was a frequent event in this disease and decreased Aβ expression correlated with shorter disease-free and overall survival. Furthermore, Aβ levels were significantly lower in multiple histological subtypes of both in situ and malignant breast cancer compared to adjacent normal breast tissue, suggesting that Aβ loss is an early event in breast cancer development. Together, this highlights a role for Aβ as a predisposition gene in breast cancer and potentially additional cancers.
Authors
Sahar Mazhar, Caitlin M. O’Connor, Alexis Harold, Amanda C. Dowdican, Peter J. Ulintz, Erika N. Hanson, Yuping Zhang, Michelle F. Jacobs, Sofia D. Merajver, Mark W. Jackson, Anthony Scott, Anieta M. Sieuwerts, Arul M. Chinnaiyan, Goutham Narla
Abstract
As a major component of intracellular trafficking, the coat protein complex II (COPII) is indispensable for cellular function during embryonic development and throughout life. The four SEC24 proteins (A-D) are essential COPII components involved in cargo selection and packaging. A human disorder corresponding to alterations of SEC24 function is currently only known for SEC24D. Here, we report that biallelic loss of SEC24C leads to a syndrome characterized by primary microcephaly, brain anomalies, epilepsy, hearing loss, liver dysfunction, anemia, and cataracts in an extended consanguineous family with four affected individuals. We show that knockout of sec24C in zebrafish recapitulates important aspects of the human phenotype. SEC24C-deficient fibroblasts display alterations in the expression of several COPII components as well as impaired anterograde trafficking to the Golgi, indicating a severe impact on COPII function. Transcriptome analysis revealed that SEC24C deficiency also impacts the proteasome and autophagy pathways. Moreover, a shift in the N-glycosylation pattern and deregulation of the N-glycosylation pathway suggest a possible secondary alteration of protein glycosylation, linking the described disorder with the congenital disorders of glycosylation.
Authors
Nina Bögershausen, Büsranur Cavdarli, Taylor Nagai, Miroslav P. Milev, Alexander Wolff, Mahsa Mehranfar, Julia Schmidt, Dharmendra Choudhary, Óscar Gutiérrez-Gutiérrez, Lukas Cyganek, Djenann Saint-Dic, Arne Zibat, Karl Köhrer, Tassilo E. Wollenweber, Dagmar Wieczorek, Janine Altmüller, Tatiana Borodina, Dilek Kaçar, Göknur Haliloğlu, Yun Li, Christian Thiel, Michael Sacher, Ela W. Knapik, Gökhan Yigit, Bernd Wollnik
Abstract
The osteo-oto-hepato-enteric (O2HE) syndrome is a severe autosomal recessive disease ascribed to loss-of-function mutations in the Unc-45 myosin chaperone A (UNC45A) gene. The clinical spectrum includes bone fragility, hearing loss, cholestasis, and life-threatening diarrhea associated with microvillus inclusion disease–like enteropathy. Here, we present molecular and functional analysis of the UNC45A c.710T>C (p.Leu237Pro) missense variant, which revealed a unique pathogenicity compared with other genetic variants causing UNC45A deficiency. The UNC45A p.Leu237Pro mutant retained chaperone activity, prevented myosin aggregation, and supported proper nonmuscle myosin II (NMII) filament formation in patient fibroblasts and human osteosarcoma (U2OS) cells. However, the mutant formed atypically stable oligomers and prevented chaperone-myosin complex dissociation, thereby inhibiting NMII functions. Similar to biallelic UNC45A deficiency, this resulted in impaired intracellular trafficking, defective recycling, and abnormal retention of transferrin at various endocytic sites. In particular, coexpression of wild-type protein attenuated the pathogenic effects of the variant by inhibiting excessive oligomer formation. Our results elucidate the pathogenic mechanisms and recessive characteristics of this variant and may aid in the development of targeted therapies.
Authors
Stephanie Waich, Karin Kreidl, Julia Vodopiutz, Arzu Meltem Demir, Adam R. Pollio, Vojtěch Dostál, Kristian Pfaller, Marianna Parlato, Nadine Cerf-Bensussan, Rüdiger Adam, Georg F. Vogel, Holm H. Uhlig, Frank M. Ruemmele, Thomas Müller, Michael W. Hess, Andreas R. Janecke, Lukas A. Huber, Taras Valovka
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