SELENOP modifies sporadic colorectal carcinogenesis and WNT signaling activity through LRP5/6 interactions

• Text
• PDF

Abstract

Although selenium deficiency correlates with colorectal cancer (CRC) risk, the roles of the selenium-rich antioxidant selenoprotein P (SELENOP) in CRC remain unclear. In this study, we defined SELENOP’s contributions to sporadic colorectal carcinogenesis. In human scRNA-seq datasets, we discovered that SELENOP expression rises as normal colon stem cells transform into adenomas that progress into carcinomas. We next examined the effects of Selenop KO in a mouse adenoma model that involves conditional, intestinal epithelial-specific deletion of the tumor suppressor adenomatous polyposis coli (Apc) and found that Selenop KO decreased colon tumor incidence and size. We mechanistically interrogated SELENOP-driven phenotypes in tumor organoids as well as CRC and noncancer cell lines. Selenop KO tumor organoids demonstrated defects in organoid formation and decreases in WNT target gene expression, which could be reversed by SELENOP restoration. Moreover, SELENOP increased canonical WNT signaling activity in noncancer and CRC cell lines. In defining SELENOP’s mechanism of action, we mapped protein-protein interactions between SELENOP and the WNT co-receptor low-density lipoprotein receptor-related protein 5/6 (LRP5/6). Lastly, we confirmed that SELENOP:LRP5/6 interactions contributed to SELENOP’s effects on WNT activity. Overall, our results position SELENOP as a modulator of the WNT signaling pathway in sporadic CRC.

Authors

Jennifer M. Pilat, Rachel E. Brown, Zhengyi Chen, Nathaniel J. Berle, Adrian P. Othon, M. Washington, Shruti A. Anant, Suguru Kurokawa, Victoria H. Ng, Joshua J. Thompson, Justin Jacobse, Jeremy A. Goettel, Ethan Lee, Yash A. Choksi, Ken S. Lau, Sarah P. Short, Christopher S. Williams

PP2A modulation overcomes multidrug resistance in chronic lymphocytic leukemia via mPTP-dependent apoptosis

• Text
• PDF

Abstract

Targeted therapies such as venetoclax (Bcl-2 inhibitor) have revolutionized the treatment of chronic lymphocytic leukemia (CLL). We previously reported that persister CLL cells in treated patients overexpress multiple anti-apoptotic proteins and display resistance to pro-apoptotic agents. Here, we demonstrated that multidrug resistant CLL cells in vivo exhibit apoptosis restriction at a premitochondrial level due to insufficient activation of the Bax and Bak proteins. Co-immunoprecipitation analyses with selective BH-domain antagonists revealed that the pleotropic pro-apoptotic protein (Bim) is prevented from activating Bax/Bak by “switching” interactions to other upregulated anti-apoptotic proteins (Mcl-1/Bcl-xL/Bcl-2). Hence, treatments that bypass Bax/Bak restriction are required to deplete these resistant cells in patients. Protein Phosphatase 2A (PP2A) contributes to oncogenesis and treatment resistance. We observed that a small molecule activator of PP2A (SMAP) induced cytotoxicity in multiple cancer cell lines and CLL samples, including multidrug resistant leukemia/lymphoma cells. The SMAP (DT-061) activated apoptosis in multidrug resistant CLL cells through induction of mitochondrial permeability transition pores (mPTP), independent of Bax/Bak. DT-061 inhibited the growth of wild type and Bax/Bak double knockout multidrug resistant CLL cells in a xenograft mouse model. Collectively, we discovered multidrug resistant CLL cells in patients, and validated a pharmacologically tractable pathway to deplete this reservoir.

Authors

Kallesh D. Jayappa, Brian Tran, Vicki L. Gordon, Christopher G. Morris, Shekhar Saha, Caroline C. Farrington, Caitlin M. O’Connor, Kaitin P. Zawacki, Krista M. Isaac, Mark Kester, Timothy P. Bender, Michael E. Williams, Craig A. Portell, Michael J. Weber, Goutham Narla

Hematopoietic progenitor kinase 1 inhibits the development and progression of pancreatic intraepithelial neoplasia

• Text
• PDF

Abstract

Ras plays an essential role in the development of acinar to ductal metaplasia (ADM) and pancreatic ductal adenocarcinoma (PDAC). However, mutant Kras is an inefficient driver for PDAC development. The switching mechanisms from low Ras activity to high Ras activity that is required for development and progression of pancreatic intraepithelial neoplasia (PanIN) are unclear. In this study, we found that HPK1 was upregulated during pancreatic injury and ADM. HPK1 interacted with the SH3 domain and phosphorylated Ras GTPase activating protein (RasGAP) and upregulated RasGAP activity. Using the transgenic mouse models of HPK1 or M46, a kinase-dead mutant of HPK1, we showed that HPK1 inhibited Ras activity and its downstream signaling and regulated acinar cell plasticity. M46 promoted the development of ADM and PanINs. Expression of M46 in KrasG12D;Bac mice promoted the infiltration of myeloid-derived suppressor cells and macrophages, inhibited the infiltration of T cells, and accelerated the progression of PanINs to invasive and metastatic PDAC, while HPK1 attenuated mutant Kras-driven PanIN progression. Our results showed that HPK1 plays an important role in ADM and the progression of PanINs by regulating Ras signaling. Loss of HPK1 kinase activity promotes an immunosuppressive tumor microenvironment and accelerates the progression of PanINs to PDAC.

Authors

Hua Wang, Rohan Moniruzzaman, Lei Li, Baoan Ji, Yi Liu, Xiangsheng Zuo, Reza Abbasgholizadeh, Jun Zhao, Guangchao Liu, Ruiqi Wang, Hongli Tang, Ryan Sun, Xiaoping Su, Tse-Hua Tan, Anirban Maitra, Huamin Wang

Basement membrane proteins in extracellular matrix characterize NF1 neurofibroma development and response to MEK inhibitor

• Text
• PDF

Abstract

Neurofibromatosis Type 1 (NF1) is one of the most common tumor-predisposing genetic disorders. Neurofibromas are NF1-associated benign tumors. A hallmark feature of neurofibromas is an abundant collagen-rich extracellular matrix (ECM) that constitutes >50% of the tumor dry weight. However, little is known about the mechanism underlying ECM deposition during neurofibroma development and treatment response. We performed a systematic investigation of ECM enrichment during plexiform neurofibroma (pNF) development, and identified basement membrane (BM) proteins, rather than major collagen isoforms, as the most upregulated ECM component. Following MEK inhibitor treatment, the ECM profile displayed an overall down-regulation signature, suggesting ECM reduction as a therapeutic benefit of MEK inhibition. Through these proteomic studies, TGF-β1 signaling was identified as playing a role in ECM dynamics. Indeed, TGF-β1 overexpression promoted pNF progression in vivo. Furthermore, by integrating single-cell RNA-sequencing, we found that immune cells including macrophages and T cells produce TGF-β1 to induce Schwann cells to produce and deposit BM proteins for ECM remodeling. Following Nf1 loss, neoplastic Schwann cells further increased BM protein deposition in response to TGF-β1. Our data delineate the regulation governing ECM dynamics in pNF and suggest that BM proteins could serve as markers for disease diagnosis and treatment response.

Authors

Chunhui Jiang, Ashwani Kumar, Ze Yu, Tracey Shipman, Yong Wang, Renee M. McKay, Chao Xing, Lu Q. Le

Deficiency in the omega-3 lysolipid transporter Mfsd2a leads to aberrant oligodendrocyte lineage development and hypomyelination

• Text
• PDF

Abstract

Patients with Autosomal Recessive Microcephaly 15 caused by deficiency in the sodium-dependent lysophosphatidylcholine (LPC) transporter Major Facilitator Superfamily Domain containing 2a (Mfsd2a) present with both microcephaly and hypomyelination, suggesting an important role of LPC uptake by oligodendrocytes in the process of myelination. Here, we demonstrate that Mfsd2a is specifically expressed in oligodendrocyte precursor cells (OPC) and is critical for oligodendrocyte development. Single cell sequencing of the oligodendrocyte lineage revealed that OPCs from OPC-specific Mfsd2a KO mice (2aOKO) underwent precocious differentiation into immature oligodendrocytes (iOLs) and impaired maturation into myelinating oligodendrocytes, correlating with postnatal brain hypomyelination. 2aOKO mice did not exhibit microcephaly, consistent with microcephaly being consequential to absence of LPC uptake at the blood-brain barrier and not from deficiency in OPCs. Lipidomic analysis showed that OPCs and iOLs from 2aOKO mice had significantly decreased phospholipids containing omega-3 fatty acids with an opposite increase in unsaturated fatty acids, that latter being products of de novo synthesis governed by Srebp-1. RNA sequencing indicated activation of the Srebp-1 pathway and defective expression of regulators of oligodendrocyte development. Taken together, these findings indicate that the transport of LPCs by Mfsd2a in OPCs is important for maintaining OPC cell state to regulate postnatal brain myelination.

Authors

Vetrivel Sengottuvel, Monalisa Hota, Jeongah Oh, Dwight L. Galam, Bernice H. Wong, Markus R. Wenk, Sujoy Ghosh, Federico Torta, David L. Silver

Gene therapy ameliorates spontaneous seizures associated with cortical neuron loss in a Cln2^R207X mouse model

• Text
• PDF

Abstract

Although a disease-modifying therapy for CLN2 disease now exists, a poor understanding of cellular pathophysiology has hampered the development of more effective and persistent therapies. Here, we investigated the nature and progression of neurological and underlying neuropathological changes in Cln2R207X mice, which carry one of the most common pathogenic mutations in human patients, but are yet to be fully characterized. Long-term electroencephalography recordings revealed progressive epileptiform abnormalities including spontaneous seizures, providing a robust and quantifiable disease-relevant phenotype. These seizures were accompanied by the loss of multiple cortical neuron populations, including those stained for interneuron markers. Further histological analysis revealed early localized microglial activation months before neuron loss started in the thalamocortical system and spinal cord, which was accompanied by astrogliosis. This pathology was more pronounced and occurred in the cortex before the thalamus or spinal cord, and differs markedly from the staging seen in mouse models of other forms of NCL. Neonatal administration of adeno-associated virus 9 (AAV9)-mediated gene therapy ameliorated the seizure and gait phenotypes and prolonged the lifespan of Cln2R207X mice, attenuating most pathological changes. Our findings highlight the importance of clinically relevant outcome measures for judging pre-clinical efficacy of therapeutic interventions for CLN2 disease.

Authors

Keigo Takahashi, Elizabeth M. Eultgen, Sophie H. Wang, Nicholas R. Rensing, Hemanth R. Nelvagal, Joshua T. Dearborn, Olivier Danos, Nicholas Buss, Mark S. Sands, Michael Wong, Jonathan D. Cooper

C5aR1 signaling triggers lung immunopathology in COVID-19 through neutrophil extracellular traps

• Text
• PDF

Abstract

Patients with severe COVID-19 develop acute respiratory distress syndrome (ARDS) that may progress to cytokine storm syndrome, organ dysfunction, and death. Considering that complement component 5a (C5a), through its cellular receptor C5aR1, has potent proinflammatory actions, and plays immunopathological roles in inflammatory diseases, we investigated whether C5a/C5aR1 pathway could be involved in COVID-19 pathophysiology. C5a/C5aR1 signaling increased locally in the lung, especially in neutrophils of critically ill COVID-19 patients compared to patients with influenza infection, as well as in the lung tissue of K18-hACE2 Tg mice (Tg mice) infected with SARS-CoV-2. Genetic and pharmacological inhibition of C5aR1 signaling ameliorated lung immunopathology in Tg-infected mice. Mechanistically, we found that C5aR1 signaling drives neutrophil extracellular trap (NET)s-dependent immunopathology. These data confirm the immunopathological role of C5a/C5aR1 signaling in COVID-19 and indicate that antagonists of C5aR1 could be useful for COVID-19 treatment.

Authors

Bruna M.S. Silva, Giovanni F. Gomes, Flavio P. Veras, Seppe Cambier, Gabriel V.L. Silva, Andreza U. Quadros, Diego B. Caetité, Daniele C. Nascimento, Camila M.S. Silva, Juliana C. Costa Silva, Samara Damasceno, Ayda H. Schneider, Fabio Beretta, Sabrina S. Batah, Icaro M.S. Castro, Isadora M. Paiva, Tamara Rodrigues, Ana Salina, Ronaldo Martins, Guilherme C. Martelossi Cebinelli, Naira L. Bibo, Daniel Macedo de Melo Jorge, Helder I. Nakaya, Dario S. Zamboni, Luiz O. Leiria, Alexandre T. Fabro, José C. Alves-Filho, Eurico Arruda, Paulo Louzada-Junior, Renê D.R. Oliveira, Larissa D. Cunha, Pierre Van Mol, Lore Vanderbeke, Simon Feys, Els Wauters, Laura Brandolini, Andrea Aramini, Fernando Q. Cunha, Jörg Köhl, Marcello Allegretti, Diether Lambrechts, Joost Wauters, Paul Proost, Thiago M. Cunha

Postoperative risk of IDH mutant glioma-associated seizures and their potential management with IDH mutant inhibitors

• Text
• PDF

Abstract

Seizures are a frequent complication of adult-type diffuse gliomas, and are often difficult to control with medications. Gliomas with mutations in isocitrate dehydrogenase 1 or 2 (IDHmut) are more likely than IDH wild-type (IDHwt) gliomas to cause seizures as part of their initial clinical presentation. However, whether IDHmut is also associated with seizures during the remaining disease course, and whether IDHmut inhibitors can reduce seizure risk, are unclear. Clinical multivariable analyses showed that preoperative seizures, glioma location, extent of resection, and glioma molecular subtype (including IDHmut status) all contribute to postoperative seizure risk in adult-type diffuse glioma patients, and that postoperative seizures are often associated with tumor recurrence. Experimentally, the metabolic product of IDHmut, D-2-hydroxyglutarate, rapidly synchronizes neuronal spike firing in a seizure-like manner, but only when nonneoplastic glial cells are present. In vitro and in vivo models can recapitulate IDHmut glioma-associated seizures, and IDHmut inhibitors currently being evaluated in glioma clinical trials inhibit seizures in those models, independent of their effects on glioma growth. These data show that postoperative seizure risk in adult-type diffuse gliomas varies in large part by molecular subtype, and that IDHmut inhibitors could play a key role in mitigating such risk in IDHmut glioma patients.

Authors

Michael Drumm, Wenxia Wang, Thomas K. Sears, Kirsten Bell-Burdett, Rodrigo Javier, Kristen Y. Cotton, Brynna T. Webb, Kayla T. Byrne, Dusten Unruh, Vineeth Thirunavu, Jordain Walshon, Alicia Steffens, Kathleen McCortney, Rimas V. Lukas, Joanna J. Phillips, Esraa Mohamed, John D. Finan, Lucas Santana-Santos, Amy B. Heimberger, Colin K. Franz, Jonathan E. Kurz, Jessica W. Templer, Geoffrey T. Swanson, Craig Horbinski

DPP4 inhibition impairs senohemostasis to improve plaque stability in atherosclerotic mice

• Text
• PDF

Abstract

Senescent vascular smooth muscle cells (VSMCs) accumulate in the vasculature with age and tissue damage, and secrete factors that promote atherosclerotic plaque vulnerability and disease. Here, we report increased levels and activity of dipeptidyl peptidase 4 (DPP4), a serine protease, in senescent VSMCs. Analysis of the conditioned media from senescent VSMCs revealed a unique senescence-associated secretory phenotype (SASP) signature comprising many complement and coagulation factors; silencing or inhibiting DPP4 reduced these factors and increased cell death. Serum samples from persons with high risk for cardiovascular disease contained high levels of DPP4-regulated complement and coagulation factors. Importantly, DPP4 inhibition reduced senescent cell burden and coagulation and improved plaque stability, while single-cell resolution of senescent VSMCs reflected the senomorphic and senolytic effects of DPP4 inhibition in murine atherosclerosis. We propose that DPP4-regulated factors could be exploited therapeutically to reduce senescent cell function, reverse senohemostasis, and improve vascular disease.

Authors

Allison B. Herman, Dimitrios Tsitsipatis, Carlos Anerillas, Krystyna Mazan-Mamczarz, Angelica E. Carr, Jordan M. Gregg, Mingyi Wang, Jing Zhang, Marc Michel, Charnae' Henry-Smith, Sophia C. Harris, Rachel Munk, Jennifer L Martindale, Yulan Piao, Jinshui Fan, Julie A. Mattison, Supriyo De, Kotb Abdelmohsen, Robert W. Maul, Toshiko Tanaka, Ann Z. Moore, Megan E. DeMouth, Simone Sidoli, Luigi Ferrucci, Yie Liu, Rafael de Cabo, Edward G. Lakatta, Myriam Gorospe

IRF7 and UNC93B1 variants in an infant with recurrent herpes simplex virus infection

• Text
• PDF

Abstract

Neonatal herpes simplex virus (HSV) infection is a devastating disease with substantial morbidity and mortality. The genetic basis of susceptibility to HSV in neonates remains undefined. We investigated a male infant with neonatal skin/eye/mouth (SEM) HSV1 disease who had complete recovery after acyclovir but developed HSV1 encephalitis at 1 year of age. Immune work up showed an anergic peripheral blood monocyte cytokine (PBMC) response to TLR3 stimulation but no other TLRs. Exome sequencing identified rare missense variants in IRF7 and UNC93B1. PBMC single cell RNA sequencing done during childhood revealed decreased expression of several innate immune genes and a repressed TLR3 pathway signature at baseline in several immune cell populations, including CD14 monocytes. Functional studies in fibroblasts and THP-1 showed that both variants individually suppressed TLR3-driven IRF3 promoter activity and type I interferon response in vitro. Furthermore, fibroblasts expressing the IRF7 and UNC93B1 variants had higher intracellular viral titers with blunting of the type I interferon response upon HSV1 challenge. This study reports an infant with recurrent HSV1 disease complicated by encephalitis associated with deleterious variants in IRF7 and UNC93B1 genes. Our results suggest that TLR3 pathway mutations may predispose neonates to recurrent severe HSV.

Authors

Megan H. Tucker, Wei Yu, Heather L. Menden, Sheng Xia, Carl F. Schreck, Margaret I. Gibson, Daniel A. Louiselle, Tomi Pastinen, Nikita Raje, Venkatesh Sampath