Oncogene-independent BCR-like signaling adaptation confers drug resistance in Ph-like ALL

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Abstract

Children and adults with Philadelphia chromosome-like B cell acute lymphoblastic leukemia (Ph-like B-ALL) experience high relapse rates despite best-available conventional chemotherapy. Ph-like ALL is driven by genetic alterations that activate constitutive cytokine receptor and kinase signaling, and early-phase trials are investigating the potential of tyrosine kinase inhibitor (TKI) addition to chemotherapy to improve clinical outcomes. However, preclinical studies have shown that JAK or PI3K pathway inhibition is insufficient to eradicate the most common cytokine receptor-like factor 2 (CRLF2)-rearranged Ph-like ALL subset. We thus sought to define additional essential signaling pathways required in Ph-like leukemogenesis for improved therapeutic targeting. Herein, we describe a novel adaptive signaling plasticity of CRLF2-rearranged Ph-like ALL following selective TKI pressure, which occurs in the absence of genetic mutations. Interestingly, we observed that Ph-like ALL cells have activated SRC, ERK and PI3K signaling consistent with activated B-cell receptor (BCR) signaling, although they do not express cell surface mu heavy chain (uHC). Combinatorial targeting of JAK/STAT, PI3K, and ‘BCR-like’ signaling with multiple TKIs and/or dexamethasone prevented this signaling plasticity and induced complete cell death, demonstrating a more optimal and clinically pragmatic therapeutic strategy for CRLF2-rearranged Ph-like ALL.

Authors

Christian Hurtz, Gerald B. Wertheim, Joseph P. Loftus, Daniel Blumenthal, Anne Lehman, Yong Li, Asen Bagashev, Bryan Manning, Katherine D. Cummins, Janis K. Burkhardt, Alexander E. Perl, Martin Carroll, Sarah K. Tasian

E4BP4-mediated inhibition of T follicular helper cells is compromised in autoimmune disease

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Abstract

T follicular helper (Tfh) cells are indispensable for the formation of germinal center (GC) reactions, while T follicular regulatory (Tfr) cells inhibit Tfh-mediated GC responses. Aberrant activation of Tfh cells contributes significantly to the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus (SLE). Nonetheless, the molecular mechanisms mitigating excessive Tfh cell differentiation, which in turn trigger autoimmunity, are not fully understood. Herein we demonstrate that the adenovirus E4 promoter-binding protein (E4BP4) mediates a feedback loop and acts as a transcriptional brake to inhibit Tfh cell differentiation. Furthermore, we show that such an immunological mechanism is compromised in patients with SLE. Establishing mice with either conditional knock-out (cKO) or knock-in (cKI) of the E4bp4 gene in T cells reveals that E4BP4 strongly inhibits Tfh cell differentiation. Mechanistically, E4BP4 deregulates Bcl6 transcription by recruiting the repressive epigenetic modifiers HDAC1 and EZH2. E4BP4 phosphorylation site mutants had limited capability with regard to inhibiting Tfh cell differentiation. In SLE, we detected impaired phosphorylation of E4BP4, finding that this compromised transcription factor is positively correlated with disease activity. These findings unveiled molecular mechanisms by which E4BP4 restrains Tfh cell differentiation, whose compromised function is associated with uncontrolled autoimmune reactions in SLE.

Authors

Zijun Wang, Ming Zhao, Jinghua Yin, Limin Liu, Longyuan Hu, Yi Huang, Aiyun Liu, Jiajun Ouyang, Xiaoli Min, Shijia Rao, Wenhui Zhou, Haijing Wu, Akihiko Yoshimura, Qianjin Lu

Longitudinal study reveals HIV-1-infected CD4⁺ T cell dynamics during long-term antiretroviral therapy

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Abstract

Proliferation of CD4+ T cells harboring HIV-1 proviruses is a major contributor to viral persistence in people on antiretroviral therapy (ART). To determine whether differential rates of clonal proliferation or HIV-1-specific CTL pressure shape the provirus landscape, we performed the intact proviral DNA assay (IPDA) and obtained 661 near-full length provirus sequences from eight individuals with suppressed viral loads on ART at time points seven years apart. We observed slow decay of intact proviruses but no changes in the proportions of various types of defective proviruses. The proportion of intact proviruses in expanded clones was similar to that of defective proviruses in clones. Intact proviruses observed in clones did not have more escaped CTL epitopes than intact proviruses observed as singlets. Concordantly, total proviruses at later timepoints or observed in clones were not enriched in escaped or unrecognized epitopes. Three individuals with natural control of HIV-1 infection (controllers) on ART, included because controllers have strong HIV-1-specific CTL responses, had a smaller proportion of intact proviruses but a similar distribution of defective provirus types and escaped or unrecognized epitopes as the other individuals. This work suggests that CTL selection does not significantly check clonal proliferation of infected cells or greatly alter the provirus landscape in people on ART.

Authors

Annukka A. R. Antar, Katharine M. Jenike, Sunyoung Jang, Danielle N. Rigau, Daniel B. Reeves, Rebecca Hoh, Melissa R. Krone, Jeanne C. Keruly, Richard D. Moore, Joshua T. Schiffer, Bareng A.S. Nonyane, Frederick M. Hecht, Steven G. Deeks, Janet D. Siliciano, Ya-Chi Ho, Robert F. Siliciano

Atypical cadherin Fat4 orchestrates lymphatic endothelial cell polarity in response to flow

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Abstract

The atypical cadherin FAT4 has established roles in regulation of planar cell polarity and Hippo pathway signaling that are cell context dependent. The recent identification of FAT4 mutations in Hennekam syndrome, features of which include lymphedema, lymphangiectasia and mental retardation, uncovered an important role for FAT4 in the lymphatic vasculature. Hennekam syndrome is also caused by mutations in CCBE1 and ADAMTS3, encoding a matrix protein and protease, respectively, that regulate activity of the key pro-lymphangiogenic VEGF-C/VEGFR3 signaling axis by facilitating the proteolytic cleavage and activation of VEGF-C. The fact that FAT4, CCBE1 and ADAMTS3 mutations underlie Hennekam syndrome suggested that all three genes might function in a common pathway. We identified FAT4 as a target gene of GATA2, a key transcriptional regulator of lymphatic vascular development and in particular, lymphatic vessel valve development. Here, we demonstrate that FAT4 functions in a lymphatic endothelial cell autonomous manner to control cell polarity in response to flow and is required for lymphatic vessel morphogenesis throughout development. Our data reveal a crucial role for FAT4 in lymphangiogenesis and shed light on the mechanistic basis by which FAT4 mutations underlie a human lymphedema syndrome.

Authors

Kelly L. Betterman, Drew L. Sutton, Genevieve A. Secker, Jan Kazenwadel, Anna Oszmiana, Lillian Lim, Naoyuki Miura, Lydia Sorokin, Benjamin M. Hogan, Mark L. Kahn, Helen McNeill, Natasha L. Harvey

Melatonin inhibits cytosolic mitochondrial-DNA induced neuroinflammatory signaling in accelerated aging and neurodegeneration

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Abstract

Chronic inflammation is a pathologic feature of neurodegeneration and aging; however, the mechanism regulating this process is not understood. Melatonin, an endogenous free radical scavenger synthesized by neuronal mitochondria, decreases with aging and neurodegeneration. We proposed that insufficient melatonin levels impair mitochondrial homeostasis resulting in mitochondrial DNA (mtDNA) release, activation of cytosolic DNA mediated inflammatory response in neurons. We found increased mitochondrial oxidative stress and decreased mitochondrial membrane potential with higher mitochondrial DNA (mtDNA) release in brain and primary cerebro-cortical neurons of melatonin deficient aralkylamine N-acetyltransferase (AANAT) knockout mice. Cytosolic mtDNA activated the cGAS/STING/IRF3 pathway, stimulating inflammatory cytokine generation. We found that Huntington's disease mice increased mtDNA release, cGAS activation, and inflammation, all inhibited by exogenous melatonin. Thus, we demonstrated that cytosolic mtDNA activated the inflammatory response in aging and neurodegeneration, a process modulated by melatonin. Furthermore, our data suggest that AANAT knockout mice are a model of accelerated aging.

Authors

Abhishek Jauhari, Sergei V. Baranov, Yalikun Suofu, Jinho Kim, Tanisha Singh, Svitlana Yablonska, Fang Li, Xiaomin Wang, Patrick Oberly, M. Beth Minnigh, Samuel M. Poloyac, Diane L. Carlisle, Robert M. Friedlander

Bile acid metabolism is altered in multiple sclerosis and supplementation ameliorates neuroinflammation

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Abstract

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the CNS. Bile acids are cholesterol metabolites that can signal through receptors on cells throughout the body, including the CNS and immune system. Whether bile acid metabolism is abnormal in MS is unknown. Using global and targeted metabolomic profiling, we identified lower levels of circulating bile acid metabolites in multiple cohorts of adult and pediatric MS patients compared to controls. In white matter lesions from MS brain tissue, we noted the presence of bile acid receptors on immune and glial cells. To mechanistically examine the implications of lower levels of bile acids in MS, we studied the in vitro effects of an endogenous bile acid – tauroursodeoxycholic acid (TUDCA) on astrocyte and microglial polarization. TUDCA prevented neurotoxic (A1) polarization of astrocytes and pro-inflammatory polarization of microglia in a dose-dependent manner. TUDCA supplementation in experimental autoimmune encephalomyelitis reduced severity of disease through its effects on GPBAR1, based on behavioral and pathological measures. We demonstrate that bile acid metabolism is altered in MS; bile acid supplementation prevents polarization of astrocytes and microglia to neurotoxic phenotypes and ameliorates neuropathology in an animal model of MS. These findings identify dysregulated bile acid metabolism as a potential therapeutic target in MS.

Authors

Pavan Bhargava, Matthew D. Smith, Leah Mische, Emily P. Harrington, Kathryn C. Fitzgerald, Kyle A. Martin, Sol Kim, Arthur Anthony A. Reyes, Jaime Gonzalez-Cardona, Christina Volsko, Ajai Tripathi, Sonal Singh, Kesava Varanasi, Hannah-Noelle Lord, Keya R. Meyers, Michelle Taylor, Marjan Gharagozloo, Elias S. Sotirchos, Bardia Nourbakhsh, Ranjan Dutta, Ellen Mowry, Emmanuelle Waubant, Peter A. Calabresi

Sel1L-Hrd1 ER-associated degradation maintains β-cell identity via TGFβ signaling

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Abstract

β-cell apoptosis and dedifferentiation are two hotly-debated mechanisms underlying β-cell loss in type 2 diabetes; however, the molecular drivers underlying such events remain largely unclear. Here, we performed a side-by-side comparison of mice carrying β-cell-specific deletion of endoplasmic reticulum (ER)-associated degradation (ERAD) and autophagy. We reported that while autophagy was necessary for β-cell survival, the highly conserved Sel1L-Hrd1 ERAD protein complex was required for the maintenance of β-cell maturation and identity. Using single cell RNA-sequencing, we demonstrated that Sel1L deficiency was not associated with β-cell loss, but rather loss of β-cell identity. Sel1L-Hrd1 ERAD controlled β-cell identity via TGFβ signaling, in part by mediating the degradation of TGFβ receptor 1 (TGFβRI). Inhibition of TGFβ signaling in Sel1L-deficient β-cells augmented the expression of β-cell maturation markers and increased the total insulin content. Our data revealed distinct pathogenic effects of two major proteolytic pathways in β-cells, providing a new framework for therapies targeting distinct mechanisms of protein quality control.

Authors

Neha Shrestha, Tongyu Liu, Yewei Ji, Rachel Reinert, Mauricio Torres, Xin Li, Maria Zhang, Chih-Hang Anthony Tang, Chih-Chi Andrew Hu, Chengyang Liu, Ali Naji, Ming Liu, Jiandie D. Lin, Sander Kersten, Peter Arvan, Ling Qi

OX40+ plasmacytoid dendritic cells in the tumor microenvironment promote antitumor immunity

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Abstract

Plasmacytoid dendritic cells (pDC), the major producers of Type I interferon, are principally recognized as key mediators of antiviral immunity. However, their role in tumor immunity is less clear. Depending on the context, pDC can both promote or suppress antitumor immune responses. In this study, we identified a naturally occurring pDC subset expressing high levels of OX40 (OX40+ pDC) enriched in the tumor microenvironment (TME) of head and neck squamous cell carcinoma. OX40+ pDC were distinguished by a distinct immunostimulatory phenotype, cytolytic function and ability to synergize with conventional dendritic cells (cDC) in generating potent tumor antigen-specific CD8+ T cell responses. Transcriptomically, we found they selectively utilized EIF2 signaling and oxidative phosphorylation pathways. Moreover, depletion of pDC in the murine OX40+ pDC-rich tumor model accelerated tumor growth. Collectively, we present evidence of a pDC subset in the TME that favors antitumor immunity.

Authors

Kate O. Poropatich, Donye Dominguez, Wen-Ching Chan, Jorge Andrade, Yuanyuan Zha, Brian D. Wray, Jason Miska, Lei Qin, Lisa E. Cole, Sydney Coates, Urjeet A. Patel, Sandeep Samant, Bin Zhang

Norrin mediates tumor-promoting and -suppressive effects in glioblastoma via Notch and WNT

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Abstract

Glioblastoma (GBM) contains a subpopulation of cells, GBM stem cells (GSCs), that maintain the bulk tumor and represent a key therapeutic target. Norrin is a Wnt ligand that binds the Frizzled4 (FZD4) receptor to activate canonical Wnt signaling. While Norrin, encoded by NDP, has a well- described role in vascular development, its function in human tumorigenesis is largely unexplored. Here, we show that NDP expression is enriched in neurological cancers, including GBM, and its levels positively correlated with survival in a GBM subtype defined by low expression of ASCL1, a proneural factor. We investigated the function of Norrin and FZD4 in GSCs and found that it mediated opposing tumor-promoting and -suppressive effects on ASCL1lo and ASCL1hi GSCs. Consistent with a potential tumor suppressive effect of Norrin suggested by the tumour outcome data, we found that Norrin signaling through FZD4 inhibited growth in ASCL1lo GSCs. In contrast, in ASCL1hi GSCs Norrin promoted Notch signaling, independently of WNT, to promote tumor progression. Forced ASCL1 expression reversed the tumor suppressive effects of Norrin in ASCL1lo GSCs. Our results identify Norrin as a modulator of human brain cancer progression and reveal an unanticipated Notch mediated function of Norrin in regulating cancer stem cell biology.

Authors

Ahmed El-Sehemy, Hayden J. Selvadurai, Arturo Ortin-Martinez, Neno T. Pokrajac, Yasin Mamatjan, Nobuhiko Tachibana, Katherine J. Rowland, Lilian Lee, Nicole I. Park, Kenneth D. Aldape, Peter Dirks, Valerie A. Wallace

Diminished hepatic IFN response following HCV clearance triggers HBV reactivation in coinfection

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Abstract

In patients with HBV and HCV coinfection, HBV reactivation leading to severe hepatitis has been reported with the use of direct-acting antivirals (DAAs) to treat HCV infection. Here we study the molecular mechanisms behind this viral interaction. In coinfected cell culture and humanized mice, HBV replication was suppressed by HCV coinfection. In vitro, HBV suppression was attenuated when interferon signaling was blocked. In vivo, HBV viremia, after initial suppression by HCV super-infection, rebounded following HCV clearance by DAA treatment that was accompanied by a reduced hepatic interferon response. Using blood samples of coinfected patients, interferon-stimulated gene products including C-X-C motif chemokine 10 (CXCL10) and C-C motif chemokine ligand 5 (CCL5), and alanine aminotransferase (ALT) were identified to have predictive value for HBV reactivation after HCV clearance. Taken together, our data suggest that HBV reactivation is a result of diminished hepatic interferon response following HCV clearance and identifies serologic markers that can predict HBV reactivation in DAA-treated HBV-HCV coinfected persons.

Authors

Xiaoming Cheng, Takuro Uchida, Yuchen Xia, Regina Umarova, Chun-Jen Liu, Pei-Jer Chen, Anuj Gaggar, Vithika Suri, Marcus Maximilian Mücke, Johannes Vermehren, Stefan Zeuzem, Yuji Teraoka, Mitsutaka Osawa, Hiroshi Aikata, Keiji Tsuji, Nami Mori, Shuhei Hige, Yoshiyasu Karino, Michio Imamura, Kazuaki Chayama, T. Jake Liang