Vicente Quiroz, Laura Planas-Serra, Abigail Sveden, Amy Tam, Hyo M. Kim, Umar Zubair, Dario Resch, Afshin Saffari, Matt C. Danzi, Stephan Züchner, Maya Chopra, Luca Schierbaum, Aurora Pujol, Erik A. Eklund, Darius Ebrahimi-Fakhari
Research advances over the past 30 years have confirmed a critical role for genetics in the etiology of dilated cardiomyopathies (DCMs). However, full knowledge of the genetic architecture of DCM remains incomplete. We identified candidate DCM causal gene, C10orf71, in a large family with 8 patients with DCM by whole-exome sequencing. Four loss-of-function variants of C10orf71 were subsequently identified in an additional group of492 patients with sporadic DCM from 2 independent cohorts. C10orf71 was found to be an intrinsically disordered protein specifically expressed in cardiomyocytes. C10orf71-KO mice had abnormal heart morphogenesis during embryonic development and cardiac dysfunction as adults with altered expression and splicing of contractile cardiac genes. C10orf71-null cardiomyocytes exhibited impaired contractile function with unaffected sarcomere structure. Cardiomyocytes and heart organoids derived from human induced pluripotent stem cells with C10orf71 frameshift variants also had contractile defects with normal electrophysiological activity. A rescue study using a cardiac myosin activator, omecamtiv mecarbil, restored contractile function in C10orf71-KO mice. These data support C10orf71 as a causal gene for DCM by contributing to the contractile function of cardiomyocytes. Mutation-specific pathophysiology may suggest therapeutic targets and more individualized therapy.
Yang Li, Ke Ma, Zhujun Dong, Shijuan Gao, Jing Zhang, Shan Huang, Jie Yang, Guangming Fang, Yujie Li, Xiaowei Li, Carrie Welch, Emily L. Griffin, Prema Ramaswamy, Zaheer Valivullah, Xiuying Liu, Jianzeng Dong, Dao Wen Wang, Jie Du, Wendy K. Chung, Yulin Li
Osteogenesis imperfecta (OI) type V is the second most common form of OI, distinguished by hyperplastic callus formation and calcification of the interosseous membranes in addition to bone fragility. It is caused by a recurrent, dominant pathogenic variant (c.-14C>T) in IFITM5. Here, we generated a conditional Rosa26 knock-in mouse model to study the mechanistic consequences of the recurrent mutation. Expression of the mutant Ifitm5 in osteo-chondroprogenitor or chondrogenic cells resulted in low bone mass and growth retardation. Mutant limbs showed impaired endochondral ossification, cartilage overgrowth, and abnormal growth plate architecture. The cartilage phenotype correlates with the pathology reported in OI type V patients. Surprisingly, expression of mutant Ifitm5 in mature osteoblasts caused no obvious skeletal abnormalities. In contrast, earlier expression in osteo-chondroprogenitors was associated with increase in the skeletal progenitor population within the periosteum. Lineage tracing showed that chondrogenic cells expressing the mutant Ifitm5 showed decreased differentiation into osteoblastic cells in diaphyseal bone. Moreover, mutant IFITM5 disrupts early skeletal homeostasis in part by activating ERK signaling and downstream SOX9 protein, and inhibition of these pathways partially rescued the phenotype in mutant animals. These data identify the contribution of a signaling defect altering osteo-chondroprogenitor differentiation as a driver in the pathogenesis of OI type V.
Ronit Marom, I-Wen Song, Emily C. Busse, Megan E. Washington, Ava S. Berrier, Vittoria C. Rossi, Laura Ortinau, Youngjae Jeong, Ming-Ming Jiang, Brian C. Dawson, Mary Adeyeye, Carolina Leynes, Caressa D. Lietman, Bridget M. Stroup, Dominyka Batkovskyte, Mahim Jain, Yuqing Chen, Racel Cela, Alexis Castellon, Alyssa A. Tran, Isabel Lorenzo, D. Nicole Meyers, Shixia Huang, Alicia Turner, Vinitha Shenava, Maegen Wallace, Eric Orwoll, Dongsu Park, Catherine G. Ambrose, Sandesh C.S. Nagamani, Jason D. Heaney, Brendan H. Lee
GNAO1 mutated in pediatric encephalopathies encodes the major neuronal G-protein Gαo. Of >80 pathogenic mutations, most are single amino acid substitutions spreading across Gαo sequence. We perform extensive characterization of Gαo mutants showing abnormal GTP uptake and hydrolysis, and deficiencies to bind Gβγ and RGS19. Plasma membrane localization of Gαo is decreased for a subset of mutations that leads to epilepsy; dominant interactions with GPCRs also emerge for the more severe mutants. Pathogenic mutants massively gain interaction with Ric8A and, surprisingly, Ric8B proteins, delocalizing them from cytoplasm to Golgi. Of these two mandatory Gα-subunit chaperones, Ric8A is normally responsible for the Gαi/o, Gαq, and Gα12/13 subfamilies, and Ric8B solely for Gαs/olf. Ric8A/B mediate the disease dominance when engaging in neomorphic interactions with pathogenic Gαo through disbalancing the neuronal G protein signaling networks. As the strength of Gαo-Ric8B interactions correlates with disease severity, our study further identifies an efficient biomarker and predictor for clinical manifestations in GNAO1 encephalopathies. Our work discovers the neomorphic molecular mechanism of mutations underlying pediatric encephalopathies and offers insights to other maladies caused by G protein misfunctioning and further genetic diseases.
Gonzalo P. Solis, Alexey Koval, Jana Valnohova, Arghavan Kazemzadeh, Mikhail Savitsky, Vladimir L. Katanaev
Trisomy 21 (T21), a recurrent aneuploidy occurring in 1:800 births, predisposes to congenital heart disease (CHD) and multiple extracardiac phenotypes. Despite a definitive genetic etiology, the mechanisms by which T21 perturbs development and homeostasis remain poorly understood. We compared the transcriptome of CHD tissues from 49 patients with T21 and 226 with euploid CHD (eCHD). We resolved cell lineages that misexpressed T21 transcripts by cardiac single-nucleus RNA sequencing and RNA in situ hybridization. Compared with eCHD samples, T21 samples had increased chr21 gene expression; 11-fold-greater levels (P = 1.2 × 10–8) of SOST (chr17), encoding the Wnt inhibitor sclerostin; and 1.4-fold-higher levels (P = 8.7 × 10–8) of the SOST transcriptional activator ZNF467 (chr7). Euploid and T21 cardiac endothelial cells coexpressed SOST and ZNF467; however, T21 endothelial cells expressed 6.9-fold more SOST than euploid endothelial cells (P = 2.7 × 10–27). Wnt pathway genes were downregulated in T21 endothelial cells. Expression of DSCAM, residing within the chr21 CHD critical region, correlated with SOST (P = 1.9 × 10–5) and ZNF467 (P = 2.9 × 10–4). Deletion of DSCAM from T21 endothelial cells derived from human induced pluripotent stem cells diminished sclerostin secretion. As Wnt signaling is critical for atrioventricular canal formation, bone health, and pulmonary vascular homeostasis, we concluded that T21-mediated increased sclerostin levels would inappropriately inhibit Wnt activities and promote Down syndrome phenotypes. These findings imply therapeutic potential for anti-sclerostin antibodies in T21.
David M. McKean, Qi Zhang, Priyanka Narayan, Sarah U. Morton, Viktoria Strohmenger, Vi T. Tang, Sophie McAllister, Ananya Sharma, Daniel Quiat, Daniel Reichart, Daniel M. DeLaughter, Hiroko Wakimoto, Joshua M. Gorham, Kemar Brown, Barbara McDonough, Jon A. Willcox, Min Young Jang, Steven R. DePalma, Tarsha Ward, Pediatric Cardiac Genomics Consortium Investigators, Richard Kim, John D. Cleveland, J.G. Seidman, Christine E. Seidman
Primary lymphedema (PL), characterized by tissue swelling, fat accumulation and fibrosis, results from defective lymphatic vessels or valves caused by mutations in genes involved in development, maturation and function of the lymphatic vascular system. Pathogenic variants in various genes have been identified in about 30% of PL cases. By screening of a cohort of 755 individuals with PL, we identified two TIE1 (tyrosine kinase with immunoglobulin- and epidermal growth factor-like domains 1) missense variants and one truncating variant, all predicted to be pathogenic by bioinformatic algorithms. The TIE1 receptor, in complex with TIE2, binds angiopoietins to regulate the formation and remodelling of blood and lymphatic vessels. The premature stop codon mutant encoded an inactive truncated extracellular TIE1 fragment with decreased mRNA stability and the amino acid substitutions led to decreased TIE1 signaling activity. By reproducing the two missense variants in mouse Tie1 via CRISPR-Cas9, we showed that both cause edema and are lethal in homozygous mice. Thus, our results indicate that TIE1 loss-of-function variants can cause lymphatic dysfunction in patients. Together with our earlier demonstration that ANGPT2 loss-of-function mutations can also cause PL, our results emphasize the important role of the ANGPT2-TIE1 pathway in lymphatic function.
Pascal Brouillard, Aino Murtomäki, Veli-Matti Leppänen, Marko Hyytiäinen, Sandrine Mestre, Lucas Potier, Laurence M. Boon, Nicole Revencu, Arin K. Greene, Andrey Anisimov, Miia H. Salo, Reetta Hinttala, Lauri Eklund, Isabelle Quéré, Kari Alitalo, Miikka Vikkula
Molecular profiling of clear cell RCC (ccRCC) tumors of clinical trial patients has identified distinct transcriptomic signatures with predictive value, yet data in non-clear cell variants (nccRCC) are lacking. We examined the transcriptional profiles of RCC tumors representing key molecular pathways, from a multi-institutional, real-world patient cohort, including ccRCC (n = 508) and centrally-reviewed nccRCC (n = 149) samples. ccRCC had increased angiogenesis signature scores compared to the heterogeneous group of nccRCC tumors (mean z-score 0.37 vs –0.99, P < 0.001), while cell cycle, fatty acid oxidation (FAO)/AMPK signaling, fatty acid synthesis (FAS)/pentose phosphate signature scores were increased in one or more nccRCC subtypes. Among both ccRCC and nccRCC tumors, T-effector scores statistically correlated with increased immune cell infiltration and were more commonly associated with immunotherapy-related markers (PD-L1+/TMB-High/MSI-High). In conclusion, this study provides evidence of differential gene transcriptional profiles among ccRCC vs nccRCC tumors, providing new insights for optimizing personalized and histology-specific therapeutic strategies for patients with advanced RCC.
Pedro Barata, Shuchi Gulati, Andrew Elliott, Hans J. Hammers, Earle F. Burgess, Benjamin A. Gartrell, Sourat Darabi, Mehmet A. Bilen, Arnab Basu, Daniel M. Geynisman, Nancy A. Dawson, Matthew R. Zibelman, Tian Zhang, Shuanzeng Wei, Charles J. Ryan, Elisabeth I. Heath, Kelsey A. Poorman, Chadi Nabhan, Rana R. McKay
T cell acute lymphoblastic leukemia (T-ALL) is an aggressive immature T cell cancer. Mutations in IL7R have been analyzed genetically, but downstream effector functions such as STAT5A and STAT5B hyperactivation are poorly understood. Here, we studied the most frequent and clinically challenging STAT5BN642H driver in T cell development and immature T cell cancer onset and compared it with STAT5A hyperactive variants in transgenic mice. Enhanced STAT5 activity caused disrupted T cell development and promoted an early T cell progenitor–ALL phenotype, with upregulation of genes involved in T cell receptor (TCR) signaling, even in absence of surface TCR. Importantly, TCR pathway genes were overexpressed in human T-ALL and mature T cell cancers and activation of TCR pathway kinases was STAT5 dependent. We confirmed STAT5 binding to these genes using ChIP-Seq analysis in human T-ALL cells, which were sensitive to pharmacologic inhibition by dual STAT3/5 degraders or ZAP70 tyrosine kinase blockers in vitro and in vivo. We provide genetic and biochemical proof that STAT5A and STAT5B hyperactivation can initiate T-ALL through TCR pathway hijacking and suggest similar mechanisms for other T cell cancers. Thus, STAT5 or TCR component blockade are targeted therapy options, particularly in patients with chemoresistant clones carrying STAT5BN642H.
Tobias Suske, Helena Sorger, Gabriele Manhart, Frank Ruge, Nicole Prutsch, Mark W. Zimmerman, Thomas Eder, Diaaeldin I. Abdallah, Barbara Maurer, Christina Wagner, Susann Schönefeldt, Katrin Spirk, Alexander Pichler, Tea Pemovska, Carmen Schweicker, Daniel Pölöske, Emina Hubanic, Dennis Jungherz, Tony Andreas Müller, Myint Myat Khine Aung, Anna Orlova, Ha Thi Thanh Pham, Kerstin Zimmel, Thomas Krausgruber, Christoph Bock, Mathias Müller, Maik Dahlhoff, Auke Boersma, Thomas Rülicke, Roman Fleck, Elvin Dominic de Araujo, Patrick Thomas Gunning, Tero Aittokallio, Satu Mustjoki, Takaomi Sanda, Sylvia Hartmann, Florian Grebien, Gregor Hoermann, Torsten Haferlach, Philipp Bernhard Staber, Heidi Anne Neubauer, Alfred Thomas Look, Marco Herling, Richard Moriggl
Mutations in genes encoding chromatin modifiers are enriched among mutations causing intellectual disability. The continuing development of the brain postnatally, coupled with the inherent reversibility of chromatin modifications, may afford an opportunity for therapeutic intervention following a genetic diagnosis. Development of treatments requires an understanding of protein function and models of the disease. Here, we provide a mouse model of Say-Barber-Biesecker-Young-Simpson syndrome (SBBYSS) (OMIM 603736) and demonstrate proof-of-principle efficacy of postnatal treatment. SBBYSS results from heterozygous mutations in the KAT6B (MYST4/MORF/QFK) gene and is characterized by intellectual disability and autism-like behaviors. Using human cells carrying SBBYSS-specific KAT6B mutations and Kat6b heterozygous mice (Kat6b+/–), we showed that KAT6B deficiency caused a reduction in histone H3 lysine 9 acetylation. Kat6b+/– mice displayed learning, memory, and social deficits, mirroring SBBYSS individuals. Treatment with a histone deacetylase inhibitor, valproic acid, or an acetyl donor, acetyl-carnitine (ALCAR), elevated histone acetylation levels in the human cells with SBBYSS mutations and in brain and blood cells of Kat6b+/– mice and partially reversed gene expression changes in Kat6b+/– cortical neurons. Both compounds improved sociability in Kat6b+/– mice, and ALCAR treatment restored learning and memory. These data suggest that a subset of SBBYSS individuals may benefit from postnatal therapeutic interventions.
Maria I. Bergamasco, Hannah K. Vanyai, Alexandra L. Garnham, Niall D. Geoghegan, Adam P. Vogel, Samantha Eccles, Kelly L. Rogers, Gordon K. Smyth, Marnie E. Blewitt, Anthony J. Hannan, Tim Thomas, Anne K. Voss
The mammalian SUMO-targeted E3 Ubiquitin Ligase, Rnf4, has been reported to act as a regulator of DNA repair, but the importance of RNF4 as a tumor suppressor has not been tested. Using a conditional-knockout mouse model, we deleted Rnf4 in the B cell lineage to test the importance of RNF4 for growth of somatic cells. Although Rnf4 conditional-knockout B cells exhibited substantial genomic instability, Rnf4 deletion caused no increase in tumor susceptibility. In contrast, Rnf4 deletion extended the healthy lifespan of mice expressing an oncogenic c-myc transgene. Rnf4 activity is essential for normal DNA replication, and in its absence, there was a failure in ATR-CHK1 signaling of replication stress. Factors that normally mediate replication fork stability, including members of the Fanconi Anemia gene family and the helicases, PIF1 and RECQL5, showed reduced accumulation at replication forks in the absence of RNF4. RNF4 deficiency also resulted in an accumulation of hyper-SUMOylated proteins in chromatin, including members of the SMC5/6 complex, which contributes to replication failure by a mechanism dependent on RAD51. These findings indicate that RNF4, which shows increased expression in multiple human tumor types, is a potential target for anti-cancer therapy, especially in tumors expressing c-myc.
Joonyoung Her, Haiyan Zheng, Samuel F. Bunting