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
The surface receptor CD8α is present on 20-80% of human (but not mouse) NK cells, yet its function on NK cells remains poorly understood. CD8α expression on donor NK cells was associated with a lack of therapeutic responses for leukemia patients in prior studies, thus we hypothesized that CD8α may impact critical NK cell functions. Here, we discovered that CD8α- NK cells had improved control of leukemia in xenograft models, compared to CD8α+ NK cells, likely due to an enhanced capacity for proliferation. Unexpectedly, CD8α expression was induced on approximately 30% of previously CD8α- NK cells following IL-15 stimulation. These ‘induced’ CD8α+ (‘iCD8α+’) NK cells had the greatest proliferation, responses to IL-15 signaling, and metabolic activity, compared to those that sustained existing CD8α expression (‘sustained CD8α+) or those that remained CD8α- (‘persistent CD8α-‘). These iCD8α+ cells originated from an IL-15Rβ high NK cell population, with CD8α expression dependent on the transcription factor RUNX3. Moreover, CD8A CRISPR/Cas9 deletion resulted in enhanced responses through the activating receptor NKp30, possibly by modulating KIR inhibitory function. Thus, CD8α status identifies human NK cell capacity for IL-15-induced proliferation and metabolism in a time-dependent fashion and exhibits a suppressive effect on NK cell activating receptors.
Celia C. Cubitt, Pamela Wong, Hannah K. Dorando, Jennifer A. Foltz, Jennifer Tran, Lynne Marsala, Nancy D. Marin, Mark Foster, Timothy Schappe, Hijab Fatima, Michelle Becker-Hapak, Alice Y. Zhou, Kimberly Hwang, Miriam T. Jacobs, David A. Russler-Germain, Emily M. Mace, Melissa M. Berrien-Elliott, Jacqueline E. Payton, Todd A. Fehniger
Pathogenic variants in VCP cause multisystem proteinopathy (MSP), a disease characterized by multiple clinical phenotypes including inclusion body myopathy, Paget’s disease of the bone, and frontotemporal dementia (FTD). How such diverse phenotypes are driven by pathogenic VCP variants is not known. We found that these diseases exhibit a common pathologic feature, ubiquitinated intranuclear inclusions affecting myocytes, osteoclasts and neurons. Moreover, knock-in cell lines harboring MSP variants show a reduction in nuclear VCP. Given that MSP is associated with neuronal intranuclear inclusions comprised of TDP-43 protein, we developed a cellular model whereby proteostatic stress results in the formation of insoluble intranuclear TDP-43 aggregates. Consistent with a loss of nuclear VCP function, cells harboring MSP variants or cells treated with VCP inhibitor exhibited decreased clearance of insoluble intranuclear TDP-43 aggregates. Moreover, we identified four compounds that activate VCP primarily by increasing D2 ATPase activity whereby pharmacologic VCP activation appears to enhance clearance of insoluble intranuclear TDP-43 aggregate. Our findings suggest that VCP function is important for nuclear protein homeostasis, that impaired nuclear proteostasis may contribute to MSP, and that VCP activation may be potential therapeutic by virtue of enhancing the clearance of intranuclear protein aggregates.
Jessica M. Phan, Benjamin C. Creekmore, Aivi T. Nguyen, Darya D. Bershadskaya, Nabil F. Darwich, Carolyn N. Mann, Edward B. Lee
Intratumoral regulatory T cells (Tregs) are key mediators of cancer immunotherapy resistance, including anti-PD-(L)1 immune checkpoint blockade (ICB). The mechanisms driving Treg infiltration into the tumor microenvironment (TME) and the consequence on CD8+ T cell exhaustion remains elusive. Herein, we report that heat shock protein gp96 (GRP94) is indispensable for Treg tumor infiltration, primarily through gp96’s roles in chaperoning integrins. Among various gp96-dependent integrins, we found that only LFA-1 (αL integrin) but not αV, CD103 (αE) or β7 integrin was required for Treg tumor homing. Loss of Treg infiltration into the TME by genetically deleting gp96/LFA-1 potently induces rejection of multiple ICB-resistant murine cancer models in a CD8+ T cell-dependent manner without loss of self-tolerance. Moreover, gp96 deletion impeded Treg activation primarily by suppressing IL-2/STAT5 signaling, which also contributes to tumor regression. By competing for intratumoral IL-2, Tregs prevent activation of CD8+ tumor-infiltrating lymphocytes (TILs), drive TOX induction and induce bona fide CD8+ T cell exhaustion. By contrast, Treg ablation leads to striking CD8+ T cell activation without TOX induction, demonstrating clear uncoupling of the two processes. Our study reveals that the gp96/LFA-1 axis plays a fundamental role in Treg biology and suggests that Treg-specific gp96/LFA-1 targeting represents a valuable strategy for cancer immunotherapy without inflicting autoinflammatory conditions.
Lei Zhou, Maria Velegraki, Yi Wang, J K Mandula, Yuzhou Chang, Weiwei Liu, No-Joon Song, Hyunwoo Kwon, Tong Xiao, Chelsea Bolyard, Feng Hong, Gang Xin, Qin Ma, Mark P. Rubinstein, Haitao Wen, Zihai Li
Cerebral arteriovenous malformations (AVMs) are the most common vascular malformations worldwide and the leading cause of hemorrhagic strokes that may result in crippling neurological deficits. Here, using newly generated mouse models, we uncovered that cerebral endothelial cells (ECs) acquired mesenchymal markers and caused vascular malformations. Interestingly, we found that limiting endothelial histone deacetylase 2 (HDAC2) prevented cerebral ECs from undergoing mesenchymal differentiation and reduced cerebral AVMs. We found that endothelial expression of HDAC2 and enhancer of zeste homolog 1 (EZH1) was altered in cerebral AVMs. These alterations changed the abundance of H4K8ac and H3K27me in the genes regulating endothelial and mesenchymal differentiation, which caused the ECs to acquire mesenchymal characteristics and form AVMs. Together, this investigation demonstrated that the induction of HDAC2 altered specific histone modifications, which resulted in mesenchymal characteristics in the ECs and cerebral AVMs. The results provided insight into the epigenetic impact on AVMs.
Yan Zhao, Xiuju Wu, Yang Yang, Li Zhang, Xinjiang Cai, Sydney Chen, Abigail Vera, Jaden Ji, Kristina I. Boström, Yucheng Yao
PTEN inactivation is prevalent in human prostate cancer and causes high-grade adenocarcinoma with a long latency. Cancer associated fibroblasts (CAFs) play a pivotal role in tumor progression, but it remains elusive whether and how PTEN-deficient prostate cancers reprogram CAFs to overcome the barriers for tumor progression. Herein, we report that PTEN deficiency induces KLF5 acetylation; and interruption of KLF5 acetylation orchestrates intricate interactions between cancer cells and CAFs that enhance FGFR1 signaling and promote tumor growth. Deacetylated KLF5 promotes tumor cells to secrete TNF-α, which stimulates inflammatory CAFs to release FGF9. CX3CR1 inhibition blocks FGFR1 activation triggered by FGF9 and sensitizes PTEN-deficient prostate cancer to AKT inhibitor capivasertib. This study reveals the role of KLF5 acetylation in reprogramming CAFs and provides a rational for combined therapies using inhibitors of AKT and CX3CR1.
Baotong Zhang, Mingcheng Liu, Fengyi Mai, Xiawei Li, Wenzhou Wang, Qingqing Huang, Xiancai Du, Weijian Ding, Yixiang Li, Benjamin Barwick, Jianping Ni, Adeboye Osunkoya, Yuanli Chen, Wei Zhou, Siyuan Xia, Jin-Tang Dong
Endothelial cells (ECs) in the descending aorta are exposed to high laminar shear stress, and this supports an anti-inflammatory phenotype. High laminar shear stress also induces flow-aligned cell elongation and front-rear polarity, but whether these are required for the anti-inflammatory phenotype is unclear. Here, we showed that Caveolin-1-rich microdomains polarize to the downstream end of ECs that are exposed to continuous high laminar flow. These microdomains were characterized by high membrane rigidity, filamentous actin (F-actin), and raft-associated lipids. Transient receptor potential vanilloid-type 4 (TRPV4) ion channels were ubiquitously expressed on the plasma membrane but mediated localized Ca2+ entry only at these microdomains where they physically interacted with clustered Caveolin-1. These focal Ca2+ bursts activated endothelial nitric oxide synthase (eNOS) within the confines of these domains. Importantly, we found that signaling at these domains required both cell body elongation and sustained flow. Finally, TRPV4 signaling at these domains was necessary and sufficient to suppress inflammatory gene expression, and exogenous activation of TRPV4 channels ameliorated the inflammatory response to stimuli both in vitro and in vivo. Our work revealed a polarized mechanosensitive signaling hub in arterial ECs that dampens inflammatory gene expression and promotes cell resilience.
Soon-Gook Hong, Julianne W. Ashby, John P. Kennelly, Meigan Wu, Michelle Steel, Eesha Chattopadhyay, Rob Foreman, Peter Tontonoz, Elizabeth J. Tarling, Patric Turowski, Marcus Gallagher-Jones, Julia J. Mack
Diffuse midline glioma (DMG) H3K27-altered is one of the devastating childhood cancers. Radiation therapy remains the only effective treatment yet provides a 5-year survival rate of only 1%. Several clinical trials have attempted to enhance radiation anti-tumor activity using radiosensitizing agents, although none have been successful. Given this, there is a critical need for identifying effective therapeutics to enhance radiation sensitivity for the treatment of DMG. Using high-throughput radiosensitivity screening, we identified bromo- and extra-terminal domain (BET) protein inhibitors as potent radiosensitizers in DMG cells. Genetic and pharmacologic inhibition of BET bromodomain activity reduced DMG cell proliferation and enhanced radiation-induced DNA damage by inhibiting DNA repair pathways. RNA-seq and CUT & RUN showed that BET bromodomain inhibitors regulate the expression of DNA repair genes mediated by H3K27 acetylation at enhancers. BET bromodomain inhibitors enhanced DMG radiation-response in patient-derived xenografts as well as genetically engineered mouse models. Together, our results highlight BET bromodomain inhibitors as radiosensitizer and provide a rationale for developing combination therapy with radiation for the treatment of DMG.
Jun Watanabe, Matthew R. Clutter, Michael J. Gullette, Takahiro Sasaki, Eita Uchida, Savneet Kaur, Yan Mo, Kouki Abe, Yukitomo Ishi, Nozomu Takata, Manabu Natsumeda, Samantha Gadd, Zhiguo Zhang, Oren J. Becher, Rintaro Hashizume
Background: Myocarditis is clinically characterized by chest pain, arrhythmias, and heart failure, and treatment for myocarditis is often supportive. Mutations in DSP, a gene encoding the desmosomal protein desmoplakin, have been increasingly implicated in myocarditis with biomarkers and pathological features indistinguishable from other forms of myocarditis. DSP-associated myocarditis can progress to dilated cardiomyopathy with heightened arrhythmia risk. Methods: To model the cardiomyocyte aspects of DSP-associated myocarditis and assess the role of innate immunity, we generated engineered heart tissues (EHTs) from human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from patients and gene-edited healthy control hiPSC lines. Homozygous and heterozygous DSP disrupted EHTs were generated to contain 90% hiPSC-CMs and 10% healthy control human cardiac fibroblasts. We measured innate immune activation and function at baseline and in response to Toll-like receptor (TLR) stimulation in EHTs. Results: At baseline, DSP-/- EHTs displayed a transcriptomic signature of immune activation which was mirrored by EHT cytokine release. Importantly, DSP-/- EHTs were hypersensitive to TLR stimulation demonstrating greater contractile function impairment compared to isogenic controls. Compared to homozygous DSP-/- EHTs, heterozygous DSP patient-derived EHTs had less functionally impairment but also displayed heightened sensitivity to TLR stimulation. When subjected to strain, heterozygous DSP EHTs developed greater functional deficit indicating reduced contractile reserve compared to healthy control. Colchicine or NFΚB inhibitors improved baseline force production and strain-induced force deficits in DSP EHTs. Genomic correction of DSP p.R1951X using adenine base editing reduced inflammatory biomarker release from EHTs. Conclusions: Genetic reduction of DSP renders cardiomyocytes susceptible to innate immune activation and strain-dependent contractile deficits. EHTs replicate electrical and contractile phenotypes seen in human myocarditis implicating cytokine release as a key part of the myogenic susceptibility to inflammation. This heightened innate immune activation and sensitivity is a target for clinical intervention.
Daniel F. Selgrade, Dominic E. Fullenkamp, Ivana A. Chychula, Binjie Li, Lisa Dellefave-Castillo, Adi D. Dubash, Joyce Ohiri, Tanner O. Monroe, Malorie Blancard, Garima Tomar, Cory Holgren, Paul W. Burridge, Alfred L. George Jr., Alexis R. Demonbreun, Megan. Puckelwartz, Sharon A. George, Igor R. Efimov, Kathleen J. Green, Elizabeth M. McNally
The diversity of structural variants (SVs) in melanoma and how they impact oncogenesis are incompletely known. We performed harmonized analysis of SVs across melanoma histological and genomic subtypes, and we identified distinct global properties between subtypes. These included the frequency and size of SVs and SV classes, their relation to chromothripsis events, and the role of topologically associated domain (TAD) boundary altering SVs on cancer-related genes. Following our prior identification of double-stranded break repair deficiency in a subset of triple wild-type cutaneous melanoma, we identified MRE11 and NBN loss-of-function SVs in melanomas with this mutational signature. Experimental knockouts of MRE11 and NBN, followed by olaparib cell viability assays in melanoma cells, indicated that dysregulation of each of these genes may cause sensitivity to PARPi in cutaneous melanomas. Broadly, harmonized analysis of melanoma SVs revealed distinct global genomic properties and molecular drivers, which may have biological and therapeutic impact.
Jake R. Conway, Riaz Gillani, Jett Crowdis, Brendan Reardon, Jihye Park, Seung Hun Han, Breanna M. Titchen, Mouadh Benamar, Rizwan Haq, Eliezer M. Van Allen
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