Pharmacological targeting of the IL17/neutrophil axis attenuates calcific deposits in rat models of calciphylaxis

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Abstract

Calciphylaxis is a rare but life-threatening disorder characterized by ectopic calcification affecting the subcutaneous tissues and blood vessels of the skin. Once diagnosed, survival rates are less than a year and yet despite the severity of the condition, the pathobiology of calciphylaxis is ill understood. Here, we create animal models of calciphylaxis that recapitulate many characteristics of the human phenotype. We demonstrate that cutaneous calcification is preceded by inflammatory cell infiltration. We show that increased local skin inflammation, regardless of the inciting cause, in the presence of hypercalcemia and hyperphosphatemia contributes to cutaneous ectopic calcification. Genetically modified rodents lacking immune activation of T and B cells or NK cells are resistant to developing cutaneous calcification. Consistent with this, administration of the immunosuppressive cyclophosphamide rescued calcific deposits as did T cell suppression with cyclosporine. We demonstrate IL17 is upregulated in calcific skin and neutrophils are the predominant cell types expressing IL 17 and tissue alkaline phosphatase that is necessary for ectopic calcification. Targeting IL17 with a monoclonal antibody or using a myeloperoxidase inhibitor to blunt neutrophil activation notably attenuated calcific deposits in vivo. Taken together, these observations provide fresh insight into the role of the immune system and the IL17/neutrophil axis in mediating ectopic calcification in rodent models of calciphylaxis.

Authors

Bo Tao, Edward Z. Cao, James Hyun, Sivakumar Ramadoss, Juan F. Alvarez, Lianjiu Su, Qihao Sun, Zhihao Liu, Linlin Zhang, Alejandro Espinoza, Yiqian Gu, Feiyang Ma, Shen Li, Matteo Pellegrini, Arjun Deb

Single-Dose Genome Editing Therapy Rescues Auditory and Vestibular Functions in Adult Mice with DFNA41 Deafness

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Abstract

Genome editing has shown the potential to treat genetic hearing loss. However, current editing therapies for genetic hearing loss have shown efficacy only in hearing rescue. In this study, we evaluated a rescue strategy using AAV2-mediated delivery of SaCas9/sgRNA in the mature inner ear of the P2rx2V61L/+ mouse model of DFNA41, a dominant, delayed-onset, and progressive hearing loss in humans. We demonstrate that local injection in adult mice results in efficient and specific editing that abolishes the mutation without notable off-target effects or AAV genome integration. Editing effectively restores long-term auditory and vestibular function. Editing further protects P2rx2V61L/+ mice from hypersensitivity to noise-induced hearing loss (NIHL), a phenotype also observed in DFNA41 patients. Intervention at a juvenile stage broadens the frequency range rescued, highlighting the importance of early intervention. An effective and specific gRNA for the human P2RX2 V60L mutation has been identified. Our study establishes the feasibility of editing to treat DFNA41 caused by P2RX2 V60L mutation in humans and opens an avenue for using editing to rescue hearing and vestibular function while mitigating noise-induced hearing loss.

Authors

Wei Wei, Wenliang Zhu, Stewart Silver, Ariel M. Armstrong, Fletcher S. Robbins, Arun Prabhu Rameshbabu, Katherina Walz, Yizhou Quan, Wan Du, Yehree Kim, Artur A. Indzhykulian, Yilai Shu, Xue-Zhong Liu, Zheng-Yi Chen

Dual targeting CDK4/6 and CDK7 augments tumor response and anti-tumor immunity in breast cancer models

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Abstract

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have transformed the treatment landscape for hormone receptor-positive (HR+) breast cancer. However, their long-term efficacy is limited by acquired resistance, and CDK4/6i monotherapy remains ineffective in triple-negative breast cancer (TNBC). Here, we demonstrate that dual inhibition of CDK4/6 and CDK7 is a promising strategy to overcome therapeutic resistance in both HR+ and TNBC models. Kinetic analyses reveal that CDK7 inhibitors (CDK7i) primarily impair RNA polymerase II-mediated transcription rather than directly targeting cell-cycle CDKs. This transcriptional suppression attenuates E2F-driven transcriptional amplification, a key mechanism for developing CDK4/6i resistance following the degradation of the retinoblastoma protein. Consequently, combining CDK7i at minimal effective concentrations with CDK4/6i potently inhibits the growth of drug-resistant tumors. Furthermore, dual CDK4/6 and CDK7 inhibition stimulates immune-related signaling and cytokine production in cancer cells, promoting anti-tumor immune responses within the tumor microenvironment. These findings provide mechanistic insights into CDK inhibition and support the therapeutic potential of combining CDK7i with CDK4/6i for breast cancer treatment.

Authors

Sungsoo Kim, Eugene Son, Ha-Ram Park, Minah Kim, Hee Won Yang

Divergent TIR signaling domains in TLR7 and TLR9 control opposing effects on systemic autoimmunity

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Abstract

Toll like receptor (TLR) 7 and 9, endosomal sensors for RNA and DNA, are key mediators of autoreactivity. Although generally considered homologous, they paradoxically have opposing effects on lupus: TLR7 exacerbates disease while TLR9 protects from disease. How they mediate opposing effects in autoimmunity remains undetermined. We hypothesized that differences in signaling qualities of the Toll-Interleukin 1 Receptor (TIR) domains of TLR7 and TLR9 could be responsible for their opposing effects. To test this, we introduced the TIR domain of TLR9 into the endogenous TLR7 locus and the TLR7 TIR domain into the endogenous TLR9 locus of mice, creating chimeric molecules termed TLR779 and TLR997. Lupus-prone MRL/lpr mice carrying Tlr779 had greatly ameliorated disease while MRL/lpr mice carrying Tlr997 had markedly exacerbated disease compared to respective TlrWT mice. These experiments establish that TLR7 and TLR9 TIR domains have divergent properties and control disease quality, thus explaining the longstanding “TLR paradox.”

Authors

Claire Leibler, Kayla B. Thomas, Coralie Josensi, Russell C. Levack, Shuchi Smita, Shinu John, Daniel J. Wikenheiser, Sheldon Bastacky, Sebastien Gingras, Kevin M. Nickerson, Mark J. Shlomchik

Epigenetic targeting of PGBD5-dependent DNA damage in SMARCB1-deficient sarcomas

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Abstract

Despite the potential of targeted epigenetic therapies, most cancers do not respond to current epigenetic drugs. The Polycomb repressive complex EZH2 inhibitor tazemetostat was recently approved for the treatment of SMARCB1-deficient epithelioid sarcomas, based on the functional antagonism between PRC2 and SMARCB1. Through the analysis of tazemetostat-treated patient tumors, we recently defined key principles of their response and resistance to EZH2 epigenetic therapy. Here, using transcriptomic inference from SMARCB1-deficient tumor cells, we nominated the DNA damage repair kinase ATR as a target for rational EZH2 combination epigenetic therapy. We showed that EZH2 inhibition promotes DNA damage in epithelioid and rhabdoid tumor cells, at least in part via its induction of piggyBac transposable element derived 5 (PGBD5). We leveraged this collateral synthetic lethal dependency to target PGBD5-dependent DNA damage by inhibition of ATR, but not CHK1, using the ATR inhibitor elimusertib. Consequently, combined EZH2 and ATR inhibition improved therapeutic responses in diverse patient-derived epithelioid and rhabdoid tumors in vivo. This advances a combination epigenetic therapy based on EZH2-PGBD5 synthetic lethal dependency suitable for immediate translation to clinical trials for patients.

Authors

Yaniv Kazansky, Helen S. Mueller, Daniel Cameron, Phillip Demarest, Nadia Zaffaroni, Noemi Arrighetti, Valentina Zuco, Prabhjot S. Mundi, Yasumichi Kuwahara, Romel Somwar, Rui Qu, Andrea Califano, Elisa de Stanchina, Filemon S. Dela Cruz, Andrew L. Kung, Mrinal M. Gounder, Alex Kentsis

The Na_V1.5 auxiliary subunit FGF13 modulates channels by regulating membrane cholesterol independent of channel binding

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Abstract

Fibroblast growth factor homologous factors (FHFs) bind to the cytoplasmic carboxy terminus of voltage-gated sodium channels (VGSCs) and modulate channel function. Variants in FHFs or VGSCs perturbing that bimolecular interaction are associated with arrhythmias. Like some channel auxiliary subunits, FHFs exert additional cellular regulatory roles, but whether these alternative roles affect VGSC regulation is unknown. Using a separation-of-function strategy, we show that a structurally guided, binding incompetent mutant FGF13 (the major FHF in mouse heart) confers complete regulation of VGSC steady-state inactivation (SSI), the canonical effect of FHFs. In cardiomyocytes isolated from Fgf13 knockout mice, expression of the mutant FGF13 completely restores wild-type regulation of SSI. FGF13 regulation of SSI derives from effects on local accessible membrane cholesterol, which is unexpectedly polarized and concentrated in cardiomyocytes at the intercalated disc (ID) where most VGSCs localize. Fgf13 knockout eliminates the polarized cholesterol distribution and causes loss of VGSCs from the ID. Moreover, we show that the previously described FGF13-dependent stabilization of VGSC currents at elevated temperatures depends on the cholesterol mechanism. These results provide new insights into how FHFs affect VGSCs and alter the canonical model by which channel auxiliary subunits exert influence.

Authors

Aravind R. Gade, Mattia Malvezzi, Lala Tanmoy Das, Maiko Matsui, Cheng-I J. Ma, Keon Mazdisnian, Steven O. Marx, Frederick R. Maxfield, Geoffrey S. Pitt

Platelet-specific SLFN14 deletion causes macrothrombocytopenia and platelet dysfunction through dysregulated megakaryocyte and platelet gene expression

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Abstract

SLFN14-related thrombocytopenia is a rare bleeding disorder caused by SLFN14 mutations altering hemostasis in patients with platelet dysfunction. Schlafen (SLFN) proteins are highly conserved in mammals where SLFN14 is specifically expressed in megakaryocyte (MK) and erythroblast lineages. The role of SLFN14 in megakaryopoiesis and platelet function has not been elucidated. We generated a new murine model with a platelet- and MK-specific SLFN14 deletion using platelet factor-4 (PF4) cre-mediated deletion of exons 2 and 3 in Slfn14 (Slfn14;PF4-Cre) to decipher the molecular mechanisms driving the bleeding phenotype. SLFN14;PF4-Cre+ platelets displayed reduced platelet signaling to thrombin, reduced thrombin formation, increased bleeding tendency, and delayed thrombus formation as assessed by intravital imaging. Moreover, fewer in situ bone marrow MKs compared to controls. RNA sequencing and gene ontology analysis of MKs and platelets from Slfn14;PF4-Cre homozygous mice revealed altered pathways of ubiquitination, ATP activity, cytoskeleton and molecular function. In summary, we investigated how SLFN14 deletion in MKs and platelets leads to platelet dysfunction and alters their transcriptome, explaining the platelet dysfunction and bleeding in humans and mice with SLFN14 mutations.

Authors

Rachel J. Stapley, Xenia Sawkulycz, Gabriel H.M. Da Mota Araujo, Maximilian Englert, Lourdes Garcia-Quintanilla, Sophie R.M. Smith, Amna Ahmed, Elizabeth J. Haining, Nayandeep Kaur, Andrea Bacon, Andrey V. Pisarev, Natalie S. Poulter, Dean P.J. Kavanagh, Steven G. Thomas, Samantha J. Montague, Julie Rayes, Zoltan Nagy, Neil V. Morgan

TET3 is a common epigenetic immunomodulator of pathogenic macrophages

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Abstract

Through a combination of single-cell/single-nucleus RNA-sequencing (sc/snRNA-seq) data analysis, immunohistochemistry, and primary macrophage studies, we have identified pathogenic macrophages characterized by TET3 overexpression (Toe-Macs) in three major human diseases associated with chronic inflammation: metabolic dysfunction-associated steatohepatitis (MASH), non-small cell lung cancer (NSCLC), and endometriosis. These macrophages are induced by common factors present in the disease microenvironment (DME). Crucially, the universal reliance on TET3 overexpression among these macrophages enables their selective elimination as a single population, irrespective of heterogeneity in other molecular markers. In mice, depleting these macrophages via myeloid-specific Tet3 knockout markedly mitigates disease progression and the therapeutic effects are recapitulated pharmacologically using a TET3-specific small molecule degrader. Through an unexpected mode of action, TET3 epigenetically regulates expression of multiple genes key to the generation and maintenance of an inflammatory/immunosuppressive DME. We propose that Toe-Macs are a unifying feature of pathogenic macrophages that could be therapeutically targeted to treat MASH, NSCLC, endometriosis, and potentially other chronic inflammatory diseases.

Authors

Beibei Liu, Yangyang Dai, Zixin Wang, Jiahui Song, Yushu Du, Haining Lv, Stefania Bellone, Yang-Hartwich Yang, Andrew Kennedy, Songying Zhang, Muthukumaran Venkatachalapathy, Yulia V. Surovtseva, Penghua Wang, Gordon G. Carmichael, Hugh S. Taylor, Xuchen Zhang, Da Li, Yingqun Huang

Overexpression of the signaling-coordinator GAB2 can play an important role in Acute Myeloid Leukemia progression

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Abstract

Mutations that initiate AML can cause clonal expansion without transformation (“clonal hematopoiesis”). Cooperating mutations, usually in signaling genes, are needed to cause overt disease, but these may require a specific “fitness state” to be tolerated. Here, we show that nearly all AMLs arising in a mouse model expressing two common AML initiating mutations (Dnmt3aR878H and Npm1cA) acquire a single copy amplification of chromosome 7, followed by activating mutations in signaling genes. We show that overexpression of a single gene on chromosome 7 (Gab2, which coordinates signaling pathways) is tolerated in the presence of the Npm1cA mutation, can accelerate the development of AML, and is important for survival of fully transformed AML cells. GAB2 is likewise overexpressed in many human AMLs with mutations in NPM1 and/or signaling genes, and also in Acute Promyelocytic Leukemia initiated by PML::RARA; the PML::RARA fusion protein may activate GAB2 by directly binding to its 5′ flanking region. A similar pattern of GAB2 overexpression preceding mutations in signaling genes has been described in other human malignancies. GAB2 overexpression may represent an oncogene-driven adaptation that facilitates the action of signaling mutations, suggesting an important (and potentially targetable) “missing link” between the initiating and progression mutations associated with AML.

Authors

Michael H. Kramer, Stephanie N. Richardson, Yang Li, Tiankai Yin, Nichole M. Helton, Daniel R. George, Michelle Cai, Sai Mukund Ramakrishnan, Casey D.S. Katerndahl, Christopher A. Miller, Timothy J. Ley

Differential BK channel potentiation by vanzacaftor enantiomers enables therapy for modulator-ineligible people with cystic fibrosis

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Abstract

Authors

Nathalie Baumlin, Sumedha Gunewardena, Scott H. Randell, Frank Horrigan, Matthias Salathe