Genetics
Abstract
Transcriptional reprogramming has an important role in kidney glomerular disease. Using in vivo murine models of podocyte injury, we studied the roles of the FOXC2 and WT1 transcription factors (TFs) in podocyte injury. Podocytes are a crucial cell type of glomeruli, the filtration units of each nephron. Podocyte injury is often the incipient event leading to chronic kidney disease. It is well established that the TFs FOXC2 and WT1 are required in podocytes to maintain the glomerular filtration barrier. Their role in the response to injury is less well understood. Here, we tested the hypothesis that FOXC2 and WT1 act together to mediate transcriptional reprogramming in response to podocyte injury. Similarly to that of WT1, genome-wide FOXC2 binding to target genes is dynamic during the course of injury, initially increasing, but late in injury there is a dramatic decrease in FOXC2 expression and in its binding to target genes. Podocyte-specific inactivation of FoxC2 or Wt1 in adult mice limits the transcriptional response to injury. Correlating FOXC2 and WT1 ChIP-seq analyses demonstrated that they co-bind many genes expressed in podocytes. Thus, reprogramming the transcriptome involves dynamic changes in the binding of FOXC2 and WT1 to their target genes during a reparative injury response.
Authors
Sandrine Ettou, Anya Greenberg, Sangyoon Lee, Arjun Rajesh, Liang Sun, Nahid Tabibzadeh, Haruka Oishi, Ran Konoe, Phillip J. McCown, Sean Eddy, Victoria Driscoll, Tomoya Miyoshi, Ken Hiratsuka, Jason Lam, R. Sathish Srinivasan, Youngsook L. Jung, Biju Isaac, Mingwei Sun, Mary E. Taglienti, Keith Keller, Hong Chen, Matthias Kretzler, Astrid Weins, Ryuji Morizane, Shira Rockowitz, Valerie A. Schumacher, Dongwon Lee, Jordan A. Kreidberg
Abstract
We investigated whether destroying malignant cells and the associated tumor microenvironment (TME) by focal gene therapy would broaden immune checkpoint inhibitor (ICI) effectiveness. We show that ICI antitumor activity against syngeneic (murine) triple-negative breast cancer (TNBC) was augmented when a therapeutic transgene (purine nucleoside phosphorylase, referred to here as E. coli PNP) was used to cleave fludarabine (2-fluoro-arabinofuranosyl adenine) to the anticancer purine base, 2-fluoroadenine (F-Ade). We also established strong repression of anatomically distant, non-PNP-expressing tumors being treated by the same strategy. TNBC cytoreduction was associated with decreased intratumoral PD1+ Tregs, increased granzyme B+ NK cells, elevated MKI67+ T8 cells, and rapid immune clearance. Because F-Ade works by a mechanism that destroys quiescent neoplastic and supporting cells in the microenvironment, and since resistance to ICIs depends upon an intact TME, tumor killing by this approach offers a means to sensitize refractory malignancies to immune ablation and points to broad applicability against numerous cancer subtypes.
Authors
Regina Rab, Jeong S. Hong, Brendan L.C. Kinney, Nicole C. Schmitt, William B. Parker, Adrianna Westbrook, Kelsey B. Bennion, Mandy L. Ford, Douglas H. Weitzel, Paula L. Miliani de Marval, Eric J. Sorscher, Annette Ehrhardt
Abstract
Biallelic loss-of-function variants in the adaptor protein complex 4 (AP-4) disrupt trafficking of transmembrane proteins at the trans-Golgi network, including the autophagy-related protein 9A (ATG9A), leading to childhood-onset hereditary spastic paraplegia (AP-4-HSP). AP-4-HSP is characterized by features of both a neurodevelopmental and degenerative neurological disease. To investigate the molecular mechanisms underlying AP-4-HSP and identify potential therapeutic targets, we conducted an arrayed CRISPR/Cas9 loss-of-function screen of 8,478 genes, targeting the ‘druggable genome’, in a human neuronal model of AP-4 deficiency. Through this phenotypic screen and subsequent experiments, key modulators of ATG9A trafficking were identified, and complementary pathway analyses provided insights into the regulatory landscape of ATG9A transport. Knockdown of ANPEP and NPM1 enhanced ATG9A availability outside the trans-Golgi network, suggesting they regulate ATG9A localization. These findings deepen our understanding of ATG9A trafficking in the context of AP-4 deficiency and offer a framework for the development of targeted interventions for AP-4-HSP.
Authors
Marvin Ziegler, Cedric Günter, Julian E. Alecu, Xutong Xue, Hyo-Min Kim, Afshin Saffari, Alexandra K. Davies, Mustafa Sahin, Darius Ebrahimi-Fakhari
Abstract
Cystic fibrosis (CF) is a life-limiting genetic disorder caused by deleterious variants in the CFTR gene that results in altered mucus impairing the airway epithelia. Durable correction of these variants in airway cells remains a therapeutic challenge for about 10% of individuals unresponsive to CFTR modulators. A common disease-causing CFTR splice site variant, 3120+1G>A, was corrected in primary CF airway cells using base editor RNAs. Single-cell RNA sequencing revealed a remarkable increase in detectable CFTR transcript in most CF airway epithelial cell types resulting in notable enrichment of CFTR-expressing ionocytes and secretory goblet cells. Progenitor basal cell subtypes were edited, but they decreased as a fraction of total cells and CFTR-expressing cells compared with unedited cells. CRISPR base editors delivered by polymeric nanoparticles (PNPs) facilitated functional rescue of CFTR to clinically meaningful levels in immortalized and primary airway cells. PNPs delivered GFP-encoding RNA to progenitor airway cells in fully differentiated airway cultures. Vitronectin was a major component of the PNP corona that formed in vivo, but preincubation with vitronectin did not enhance delivery. Together, these findings validate a scalable, nonviral platform with compelling translational promise for treating CF and other respiratory diseases involving respiratory epithelial cell dysfunction.
Authors
Erin W. Kavanagh, Anya T. Joynt, Audrey R. Pion, Alice C. Eastman, Alianna I. Parr, Katherine L. Starego, Manav Jain, Sydney R. Shannon, Edwin J. Yoo, Gregory A. Newby, Stephany Y. Tzeng, Neeraj Sharma, Jordan J. Green, Garry R. Cutting
Abstract
Centronuclear myopathies (CNMs) are rare congenital disorders characterized by muscle weakness, fiber hypotrophy, and organelle mislocalization. Most cases arise from mutations in MTM1 or DNM2, encoding myotubularin and dynamin-2, respectively. DNM2 is a GTPase that binds lipids, oligomerizes around membranes, and mediates fission. We previously showed that DNM2 levels are elevated in MTM1-CNM patients and Mtm1–/y mice, and that normalizing DNM2 rescues disease phenotypes. However, the specific DNM2 functions driving pathology remain unclear. Here, we expressed AAV-delivered WT and DNM2 mutants in WT and Mtm1–/y mouse muscles to disrupt specific DNM2 molecular functions. In WT mice, overexpression of WT DNM2 and most mutants induced CNM-like phenotypes, including reduced force, fiber hypotrophy, and centralized nuclei, consistent with gain-of-function mechanisms. The lipid-binding-defective mutant K562E did not induce disease-like phenotype. In Mtm1–/y mice, K562E mutant markedly improved muscle force, mass, and fiber size, while others failed to rescue. Therefore, we generated Mtm1–/y Dnm2K562E/+ mice, which showed full rescue of survival, motor function, and muscle force, with improved muscle mass, fiber size, and organelle positioning despite persistently elevated DNM2 levels. This study reveals that DNM2 lipid binding, not protein abundance or GTPase activity, drives pathology, and represents the most rational therapeutic target for DNM2 therapy in MTM1-CNM.
Authors
Raquel Gómez-Oca, Xènia Massana-Muñoz, David Reiss, Juliana De Carvalho Neves, Nadege Diedhiou, Roberto Silva-Rojas, Belinda S. Cowling, Marie Goret, Jocelyn Laporte
Abstract
Germline BRCA1/2 pathogenic variant (PV) carriers have elevated young-onset breast cancer risk. To define the pretreatment genomic landscapes of young-onset gBRCA-associated breast cancer, we evaluated 136 treatment-naïve tumors diagnosed before age 50 (92.6% ≤40): gBRCA1 86(63.2%); gBRCA2 50(36.8%) in the prospective POSH study, and 66 noncarriers from The Cancer Genome Atlas. Using whole exome sequencing, we analyzed somatic variation, allele-specific loss of heterozygosity (asLOH), homologous recombination deficiency (HRD), and single-base substitution signatures (SBS). gBRCA1(93%) and gBRCA2(96%) breast cancers had high rates of asLOH, but differed significantly in average HRD scores (57.4 ± 1.3 vs 43.7 ± 1.5, P < 0.0001) and median SBS composition (%): SBS1 (aging-associated) 12.9 vs 7.3, P = 0.013; SBS18 (reactive oxygen species [ROS]-associated) 1.4 vs 0, P = 0.007; and SBS3 (HRD-associated) 27.3 vs 42.6, P = 0.002. Compared to gBRCA2 tumors, gBRCA1 tumors with asLOH were significantly enriched for alterations in Hallmark ROS, DNA repair, and epithelial-mesenchymal transition pathways. In ER-positive, HER2-negative tumors from gBRCA1/2 carriers compared to noncarriers, we found significant enrichment of RB1 (OR:6.3;95%CI:2.8–15.4;padj = 0.001), TP53 (OR:4.6;95%CI:1.9–12.1;padj = 0.017), FAT1 (OR:3.9;95%CI:1.84–8.7;padj = 0.013), and MYC (OR:4.0;95%CI:1.8–9.1;padj = 0.017) SNV/indels/CNVs, associated with CDK4/6i resistance. Together, these findings demonstrate significant differences between gBRCA1 and gBRCA2-associated breast cancers, and preexisting CDK4/6i resistance mechanisms supporting prospective trials with individualized therapy for gBRCA1 vs gBRCA2 carriers, and comparing PARPi to CDK4/6i for ER-positive gBRCA1/2-associated breast cancer.
Authors
Mwangala P. Akamandisa, Mingyi Xia, Wilson Cheah, Bradley Wubbenhorst, Kurt P. D'Andrea, Mengyao Fan, Jake S. Shilan, Dana Pueschl, Anupma Nayak, Hayley McKenzie, William Tapper, Ellen R. Copson, Ramsey I. Cutress, Susan M. Domchek, Diana M. Eccles, Katherine L. Nathanson
Abstract
Survival after lung transplantation is limited by chronic, progressive graft failure, termed chronic lung allograft dysfunction (CLAD). Graft-resident mesenchymal cells (MCs) drive CLAD pathogenesis and exhibit stable dysregulated signaling, yet the transcriptomic and epigenomic drivers underlying this fibrogenic transformation remain elusive. We used single-cell multi-omic profiling to characterize gene expression and chromatin accessibility in MCs isolated from lavage fluid of lung transplant recipients with and without CLAD, collected early post-transplantation or after disease onset. MCs obtained after CLAD onset demonstrated a distinct transcriptomic signature compared with non-CLAD controls, enabling classification of disease status at the single-cell level with > 98% accuracy using signature genes. Chromatin accessibility analyses identified enrichment of CCAAT-enhancer-binding protein family transcription factors, specifically CEBPD, in CLAD MCs. Early post-transplant MCs showed minimal accessibility differences, suggesting that CEBPD-associated regulatory changes emerge over time. Integration analyses identified eight MC states and a CLAD-specific shift towards a fibrotic state. CEBPD, SOX4, and FOXP2 were identified as putative regulators of this state with substantial overlap in predicted targets. Targeting CEBPD reversed fibrotic phenotypes of CLAD MCs (decreased ECM expression, contractility, proliferation, and migration). Together, these data provide insights into transcriptomic and epigenomic changes in post-transplant MCs, nominating biomarkers and therapeutic targets.
Authors
Lu Lu, A. Patrick McLinden, Natalie M. Walker, Ragini Vittal, Yichen Wang, Fatemeh Fattahi, Stephen T. Russell, Michael P. Combs, Joshua D. Welch, Vibha N. Lama
Abstract
Nearly 100 individuals have been identified who carry deleterious biallelic germline variants in CARD9 and experience life-threatening, invasive fungal infections caused by Ascomycetes but are otherwise resistant to other infectious agents. CARD9 is an adaptor protein expressed predominantly in myeloid cells, which functions downstream of dectin receptors, pattern recognition receptors for fungal antigens, to activate innate immune responses. The impact of CARD9 deficiency on lymphocytes, however, is less clear. We deciphered the functional consequences and delineated mechanisms of disease in a patient (P1) with a nonsense germline homozygous CARD9 variant (c.673A>T/p.K225*) and invasive Candida disease. P1’s PBMCs expressed truncated CARD9 and showed significantly reduced cytokine production in response to fungal ligands. P1 had reduced frequencies of circulating memory CD4+ TH17-like (CCR6+CXCR3–) cells. In addition, in vitro differentiation of P1’s naive CD4+ T cells into IL-17A/IL-17F–secreting cells was greatly impaired. Consistent with impaired responses of innate and adaptive immune cells from P1 in vitro, proportions of Candida-specific CD4+ T cells were strongly and selectively diminished. Our findings suggest that the CARD9 variant identified in P1 is pathogenic, affecting not only CARD9-induced immunity mediated by myeloid cells but also CD4+ T cell–intrinsic IL-17–dependent immunity and Candida-specific T cell responses.
Authors
Erika Della Mina, Carlos G. El-Haddad, Timothy A. West, Clara W.T. Chung, Jing Jing Li, Vivienne Lea, Elissa K. Deenick, Filomeen Haerynck, Jean-Laurent Casanova, Anne Puel, Cindy S. Ma, Stuart G. Tangye, Alisa Kane
Abstract
Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by pruritic skin nodules of unknown etiology. Little is known about genetic changes in PN pathogenesis, particularly somatic events, which are often implicated in inflammatory conditions. We thus performed whole-exome sequencing on 54 lesional and nonlesional skin biopsies from 17 patients with PN and 10 patients with atopic dermatitis (AD) for comparison. Somatic mutational analysis revealed that PN lesional skin harbors recurrent somatic mutations in fibrotic, neurotropic, and cancer-associated genes that are absent in adjacent PN nonlesional skin. Nonsynonymous mutations were most frequently present in NOTCH1 and the Notch signaling pathway, a key regulator of cellular proliferation and tissue fibrosis. In contrast, NOTCH1 mutations were absent in AD. Somatic copy-number analysis, combined with expression data, identified recurrently deleted and downregulated genes in PN lesional skin, which are associated with axonal guidance and extension. Follow-up immunofluorescence validation demonstrated increased NOTCH1 expression in PN lesional skin fibroblasts and increased Notch signaling in PN lesional dermis. Finally, a multicenter analysis revealed increased risk of NOTCH1-associated diseases in patients with PN. In characterizing the somatic landscape of PN, this study highlights the potential role of Notch pathway dysregulation in PN pathogenesis and fibrosis.
Authors
Ahmad Rajeh, Shahin Shahsavari, Hannah Cornman, Alexander Kollhoff, Anuj Gupta, Mindy D. Szeto, Anusha Kambala, Olusola O. Oladipo, Varsha Parthasarathy, Junwen Deng, Melika Marani, Shirin Shahsavari, Selina M. Yossef, Vedha Vaddaraju, Waleed Adawi, Yagiz M. Akiska, Davies M. Gage, Sarah Wheelan, Thomas Pritchard, Madan M. Kwatra, Yevgeniy R. Semenov, Alexander Gusev, Won Jin Ho, Srinivasan Yegnasubramanian, Shawn G. Kwatra
Loss of Tumor-Infiltrating Lymphocytes and Poor Response to Immunotherapy in IDH GOF Mutant Melanoma
Abstract
Recent innovations in melanoma treatment with immune checkpoint blockade (ICB) have improved overall outcomes for patients, however over 50% of patients still develop resistance to treatment. These patients either have intrinsic resistance, and never respond to therapy, or develop acquired resistance months or years into treatment. The mechanisms underlying ICB resistance remain poorly understood. Our data shows that isocitrate dehydrogenase gain of function (IDH GOF) mutant melanoma patients have a worse response to anti-PD1 immunotherapy. IDH mutations have been found to be oncogenic and associated with differential methylation in multiple cancers but are not yet characterized in human melanoma. Here, we investigate the clinical, immune, and transcriptional phenotypes of IDH GOF melanomas through analyses of clinical response, single-cell RNA sequencing, bulk RNA sequencing, and DNA methylation data. Single-cell data analysis shows decreased immune infiltrate and activity in the IDH GOF tumors. Bulk sequencing data demonstrates the association between IDH mutation, immune exclusion, and disruptions in global DNA methylation. The melanoma-derived genomic data presented supports previously described resistance mechanisms of IDH mutation in other cancer types and is the first demonstration of the role of IDH GOF in the human melanoma tumor microenvironment.
Authors
Emma Specht, Lakshmi Pakanati, Meng-Ju Wu, Russell W. Jenkins, Derek N. Effiom, Nabeel Bardeesy, Bradley E. Bernstein, Moshe Sade-Feldman, Christine G. Lian, Genevieve M. Boland, Elena Torlai Triglia, Sonia Cohen
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