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Tumoral RCOR2 promotes tumor development through dual epigenetic regulation of tumor plasticity and immunogenicity

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Abstract

Gain of plasticity and loss of MHC-II enable tumor cells to evade immune surveillance contributing to tumor development. Here, we showed that the transcriptional corepressor RCOR2 is a key factor that integrates two epigenetic programs surveilling tumor plasticity and immunogenicity. RCOR2 was upregulated predominantly in tumor cells and promoted tumor development in mice through reducing tumor cell death by CD4+/CD8+ T cells and inducing cancer stemness. Mechanistically, RCOR2 repressed RNF43 expression through LSD1-mediated demethylation of histone H3 at lysine 4 to induce activation of Wnt/β-catenin and tumor stemness. Simultaneously, RCOR2 inhibited CIITA expression through HDAC1/2-mediated deacetylation of histone H4 at lysine 16, leading to MHC-II silencing in tumor cells and subsequent impairment of CD4+/CD8+ T cell immunosurveillance, thereby promoting immune evasion. RCOR2 loss potentiated anti-PD-1 therapy in mouse models of cancer and correlated with better response to anti-PD-1 therapy in human patients. Collectively, these findings uncover a “two birds with one stone” effect for RCOR2, highlighting its potential as a valuable target for improved cancer therapy.

Authors

Lei Bao, Ming Zhu, Maowu Luo, Ashwani Kumar, Yan Peng, Chao Xing, Yingfei Wang, Weibo Luo

Cyclin D1 overexpression induces replication stress and microhomology-mediated end-joining dependence in mantle cell lymphoma

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Abstract

Oncogene expression can cause replication stress (RS), leading to DNA double-strand breaks (DSB) that require repair through pathways such as homologous recombination, non-homologous end-joining, and microhomology-mediated end-joining (MMEJ). Cyclin D1 (encoded by CCND1) is a well-known oncoprotein overexpressed in cancer; however, its role in RS is unknown. Using mantle cell lymphoma (MCL) as a naturally occurring model of cyclin D1 overexpression, we examined its impact on RS and DSB-repair mechanisms. Cyclin D1 overexpression elevated RS, increased DNA damage, especially during mitosis, and caused specific upregulation of MMEJ. Furthermore, cyclin D1 activates the polymerase theta (POLQ) transcription by binding its promoter loci, driving POLΘ-mediated MMEJ that is essential to withstand cyclin D1-induced RS. Moreover, concurrent ATM deficiency further intensifies RS, enhances POLQ expression and heightens reliance on MMEJ mediated DNA damage repair. Consequently, inhibition of POLΘ in cyclin D1-overexpressed settings further exacerbates RS, causing single-strand DNA gap accumulations and chromosomal instability, ultimately leading to apoptosis, an effect amplified in ATM-deficient cells. Targeting MMEJ via POLΘ inhibition is, therefore, an effective strategy in the context of cyclin D1 overexpression and ATM deficiency and may provide a unique therapeutic approach for treating MCL and other malignancies characterized by similar alterations.

Authors

Jithma Abeykoon, Shuhei Asada, Guangli Zhu, Yuna Hirohashi, Lisa Moreau, Divya R. Iyer, Sirisha Mukkavalli, Kalindi Parmar, Gabriella Zambrano, Lige Jiang, Dongni Yi, Michelle Manske, Kimberly Gwin, Rebecca L. King, James R. Cerhan, Xiaosheng Wu, Zhenkun Lou, Geoffrey I. Shapiro, Thomas Witzig, Alan D'Andrea

Hepcidin sustains Kupffer cell immune defense against bloodstream bacterial infection via gut-derived metabolites in mice

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Abstract

Bloodstream bacterial infections cause one-third of deaths from bacterial infections, and eradication of circulating bacteria is essential to prevent disseminated infections. We here found that hepcidin, the master regulator of systemic iron homeostasis, affected Kupffer cell (KC) immune defense against bloodstream bacterial infections by modulating the gut commensal bacteria-derived tryptophan derivative indole-3-propionic acid (IPA). Hepcidin deficiency impaired bacterial capture by KCs and exacerbated systemic bacterial dissemination through morphological changes in KCs. Gut microbiota depletion and fecal microbiota transplantation revealed that the gut microbiota mediated the alteration of KCs volume. Mechanistically, hepcidin deficiency led to a decreased abundance of the IPA-producing commensal Lactobacillus intestinalis and a concomitant reduction in the gut-to-liver shuttling of its metabolite IPA. IPA supplementation or Lactobacillus intestinalis colonization restored the KC volume and hepatic immune defense against bloodstream bacterial infection in hepcidin-deficient mice. Moreover, hepcidin levels in patients with bacteremia were associated with days of antibiotic usage and hospitalization. Collectively, our findings described a previously unappreciated role of hepcidin in sustaining KC-mediated hepatic defense against bloodstream bacterial infections through the gut commensal Lactobacillus intestinalis and its tryptophan derivative IPA. More importantly, restoring the crosstalk between the gut microbiota and liver through IPA-inspired therapies may offer a promising strategy for enhancing the host defense against bloodstream bacterial infections in those with low hepcidin levels and a high risk for bacterial infections.

Authors

Yihang Pan, Lihua Shen, Zehua Wu, Xueke Wang, Xiwang Liu, Yan Zhang, Qinyu Luo, Sijin Liu, Xiangming Fang, Qiang Shu, Qixing Chen

Blocking immune checkpoint LAIR1 with antibody blockade or 3-in-1 CAR T cells enhances antitumor response

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Abstract

Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment (TME) and dampen the immune response, negatively affecting patient survival. Therefore, targeting TAMs could address the limitations of current cancer treatments. However, drug development in this area remains limited. The Leukocyte-associated Immunoglobulin-like Receptor-1 (LAIR1), also called CD305, is prominently expressed on the surface of TAMs. We have uncovered a previously unrecognized immunosuppressive LAIR1 → Factor XIII A (FXIII-A) → Collagen IV pathway across various cancer types. Inhibition of LAIR1, either through knockout (Lair1–/–), antibody blockade (aLAIR1), or a chimeric antigen receptor (CAR) design (3-in-1 CAR by combining tumor targeting, T cell trafficking, and remodeling of the immunosuppressive TME in one CAR construct) provides enhanced antitumor response. LAIR1 inhibition enhances peripheral and intratumoral CD8 memory T-cell populations, induces a phenotypic shift of M2-like Macrophages towards M1, and normalizes tumor collagen IV and structural components in the TME, facilitating effective tumor-T cell interactions and tumor suppression. Enhanced antitumor responses were observed when Lair1–/– or aLAIR1 was used alone or combined with CAR T cells or when the 3-in-1 CAR T cells were used solely in chemotherapy-radiation-PD-1 blockade-resistant tumor models. These findings position LAIR1 inhibition as a promising strategy for cancer immunotherapies.

Authors

Haipeng Tao, Dongjiang Chen, Changlin Yang, Duy T. Nguyen, Georges Abboud, Ruixuan Liu, Tianyi Liu, Avirup Chakraborty, Alicia Y. Hou, Nicole A. Petit, Muhammad Abbas, Robert W. Davis, Janie Zhang, Christina Von Roemeling, Mohammed O. Gbadamosi, Linchun Jin, Tongjun Gu, Tuo Lin, Pengchen Wang, Alfonso Pepe, Diego Ivan Pedro, Hector R. Mendez-Gomez, Chao Xie, Aida Karachi, Frances Weidert, Dan Jin, Chenggang Wang, Kaytora Long-James, Elizabeth K. Molchan, Paul Castillo, John A. Ligon, Ashley P. Ghiaseddin, Elias J. Sayour, Maryam Rahman, Loic P. Deleyrolle, Betty Y.S. Kim, Duane A. Mitchell, W. Gregory Sawyer, Jianping Huang

Iron supplementation alleviates pathologies in a mouse model of facioscapulohumeral muscular dystrophy

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Abstract

Facioscapulohumeral muscular dystrophy (FSHD) is a genetic muscle disease caused by ectopic expression of the toxic protein DUX4, resulting in muscle weakness. However, the mechanism by which DUX4 exerts its toxicity remains unclear. In this study, we observed abnormal iron accumulation in muscles of patients with FSHD and in muscle-specific DUX4-expressing (DUX4-Tg) mice. Treatment with iron chelators, an iron-deficient diet, and genetic modifications inhibiting intracellular uptake of iron did not improve but rather exacerbated FSHD pathology in DUX4-Tg mice. Unexpectedly, however, iron supplementation, either from a high-iron diet or intravenous iron administration, resulted in remarkable improvement in grip strength and running performance in DUX4-Tg mice. Iron supplementation suppressed abnormal iron accumulation and the ferroptosis-related pathway involving increased lipid peroxidation in DUX4-Tg muscle. Muscle-specific DUX4 expression led to retinal vasculopathy, a part of FSHD pathology, which was prevented by iron administration. Furthermore, high-throughput compound screening of the ferroptosis pathway identified drug candidates including Ferrostatin-1 (Fer-1), a potent inhibitor of lipid peroxidation. Treatment with Fer-1 dramatically improved physical function in DUX4-Tg mice. Our findings demonstrate that DUX4-provoked toxicity is involved in the activation of the ferroptosis-related pathway and that supplementary iron could be a promising and readily available therapeutic option for FSHD.

Authors

Kodai Nakamura, Huascar-Pedro Ortuste-Quiroga, Naoki Horii, Shin Fujimaki, Toshiro Moroishi, Keiichi I. Nakayama, Shinjiro Hino, Yoshihiko Saito, Ichizo Nishino, Yusuke Ono

The human glucocorticoid receptor variant rs6190 increases blood cholesterol and promotes atherosclerosis

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Abstract

Elevated cholesterol poses cardiovascular risks. The glucocorticoid receptor (GR) harbors a still undefined role in cholesterol regulation. Here, we report that a coding single nucleotide polymorphism (SNP) in the gene en-coding the GR, rs6190, associated with increased cholesterol in women according to UK Biobank and All Of Us datasets. In SNP-genocopying mice, we found that the SNP enhanced hepatic GR activity to transactivate Pcsk9 and Bhlhe40, negative regulators of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) re-ceptors respectively. In mice, the SNP was sufficient to elevate circulating cholesterol across all lipoprotein frac-tions and the risk and severity of atherosclerotic lesions on the pro-atherogenic hAPOE*2/*2 background. The SNP effect on atherosclerosis was blocked by in vivo liver knockdown of Pcsk9 and Bhlhe40. Also, corti-costerone and testosterone were protective against the mutant GR program in cholesterol and atherosclerosis in male mice, while the SNP effect was additive to estrogen loss in females. Remarkably, we found that the mu-tant GR program was conserved in human hepatocyte-like cells using CRISPR-engineered, SNP-genocopying human induced pluripotent stem cells (hiPSCs). Taken together, our study leverages a non-rare human variant to uncover a novel GR-dependent mechanism contributing to atherogenic risk, particularly in women.

Authors

Hima Bindu Durumutla, April Haller, Greta Noble, Ashok Daniel Prabakaran, Kevin McFarland, Hannah Latimer, Akanksha Rajput, Olukunle Akinborewa, Bahram Namjou-Khales, David Y. Hui, Mattia Quattrocelli

Targeting the IL-36 receptor with spesolimab mitigates residual inflammation and prevents generalized pustular psoriasis flares

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Abstract

Authors

James G. Krueger, Mrinal K. Sarkar, Mark G. Lebwohl, Akimichi Morita, Kenneth Gordon, Rachael Bogle, Christopher Cole, Anthony Coon, Richard G. Langley, Richard B. Warren, Arash Mostaghimi, Bruce Strober, A. David Burden, Min Zheng, Aaron R. Mangold, Milan J. Anadkat, Jonathan N. Barker, Joseph F. Merola, Lam C. Tsoi, Ming Tang, Kolja Becker, Denis Delic, Christian Thoma, Johann E. Gudjonsson

Cingulate retinoic acid signaling regulates neuropathic pain and comorbid anxiodepression via extracellular matrix homeostasis

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Abstract

Neuropathic pain is often comorbid with affective disorders. Synaptic plasticity in anterior cingulate cortex (ACC) is assumed to be a crucial interface for pain perception and emotion. Laminin β1 (LAMB1), a key element of extracellular matrix (ECM) in ACC was recently revealed to convey extracellular alterations to intracellular synaptic plasticity and underlie neuropathic pain and aversive emotion. However, it remains elusive what triggers activity-dependent changes of LAMB1 and ECM remodeling after nerve injury. Here, we uncovered a key role of retinoic acid (RA)/RARB signaling in neuropathic pain and associated anxiodepression via regulation of ECM homeostasis. We showed that nerve injury reduced RA level in the serum and ACC in mice and human, which brought about downregulation of its corresponding receptor, RARB. Overexpressing RARB relieved pain hypersensitivity and comorbid anxiodepression, while silencing RARB exacerbated pain sensitivity and induced anxiodepression. Further mechanistic analysis revealed that RARB maintained ECM homeostasis via transcriptional regulation of LAMB1, reversing abnormal synaptic plasticity and eventually improved neuropathic pain and aversive emotion. Taken together with our previous study, we revealed an intracellular-extracellular-intracellular feedforward regulatory network in modulating pain plasticity. Moreover, we identified cingulate RA/RARB signaling as a promising therapeutic target for treatment of neuropathic pain and associated anxiodepression.

Authors

Zhen-Zhen Li, Wan-Neng Liu, Ke-Xin Liu, Zhi-Wei Dou, Rui Zhao, Yun Chen, Meng-Meng Wang, Tao-Zhi Wang, Fei Wang, Wen-Juan Han, Wen-Guang Chu, Xing-Xing Zheng, Rou-Gang Xie, Hua Yuan, Xiao-Fan Jiang, Xiao-Long Sun, Ceng Luo, Shengxi Wu

SOX2 regulates foregut squamous epithelial homeostasis and is lost during Barrett’s esophagus development

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Abstract

Esophageal adenocarcinoma (EA) is increasingly prevalent and is thought to arise from Barrett’s esophagus (BE), a metaplastic condition in which chronic acid and bile reflux transforms the esophageal squamous epithelium into a gastric-intestinal glandular mucosa. The molecular determinants driving this metaplasia are poorly understood. We developed a human BE organoid biobank that recapitulates BE’s molecular heterogeneity. Bulk and single-cell transcriptomics, supported by patient tissue analysis, revealed that BE differentiation reflects a balance between SOX2 (foregut/esophageal) and CDX2 (hindgut/intestinal) transcription factors. Using squamous-specific inducible Sox2 knockout (Krt5CreER/+; Sox2∆/∆; ROSA26tdTomato/+) mice, we observed increased basal proliferation, reduced squamous differentiation, and expanded metaplastic glands at the squamocolumnar junction, some tracing back to Krt5-expressing cells. CUT&RUN analysis showed SOX2 bound and promoted differentiation-associated (e.g., Krt13) and repressed proliferation-associated (e.g., Mki67) targets. Thus, SOX2 is critical for foregut squamous epithelial differentiation and its decreased expression is likely an initiating step in progression to BE and thence to EA.

Authors

Ramon U. Jin, Yuanwei Xu, Tung-Shing Lih, Yang-Zhe Huang, Toni M. Nittolo, Blake E. Sells, Olivia M. Dres, Jean S. Wang, Qing Kay Li, Hui Zhang, Jason C. Mills

Activated STING in the thymic epithelium alters T cell development and selection leading to autoimmunity

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Abstract

COPA syndrome is a monogenic disorder of immune dysregulation that leads to interstitial lung disease and high-titer autoantibodies. Constitutive activation of the innate immune molecule STING is centrally involved in disease. However, the mechanisms by which STING results in autoimmunity is not well understood in COPA syndrome and other STING-associated diseases. Prior studies show a cell autonomous role for STING in thymocyte development. Single cell data of human thymus demonstrates STING is highly expressed in medullary thymic epithelial cells (mTECs) and at levels much greater than T cells. Here, we show that in certain contexts activated STING exerts a functional role in the thymic epithelium to alter thymocyte selection and predisposes to autoimmunity. In CopaE241K/+ mice, activated STING in mTECs amplified interferon signaling, impaired macroautophagy and caused a defect in negative selection of T cell precursors. Wild-type mice given a systemic STING agonist phenocopied the selection defect and showed enhanced thymic escape of a T cell clone targeting a self-antigen also expressed in melanoma. Our work demonstrates STING activation in TECs shapes the T cell repertoire and contributes to autoimmunity, findings important for conditions that activate thymic STING.

Authors

Zimu Deng, Christopher S. Law, Santosh Kurra, Noa Simchoni, Anthony K. Shum

The E3 ubiquitin ligase Cul5 regulates hematopoietic stem cell function for steady-state hematopoiesis in mice

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Abstract

The balance of hematopoietic stem cell (HSC) self-renewal versus differentiation is essential to ensure long-term repopulation capacity while allowing response to events that require increased hematopoietic output. Proliferation and differentiation of HSCs and their progeny is controlled by the JAK/STAT pathway downstream of cytokine signaling. E3 ubiquitin ligases, like Cullin 5 (Cul5), can regulate JAK/STAT signaling by degrading signaling intermediates. Here we report that mice lacking Cul5 in hematopoietic cells (Cul5Vav-Cre) have increased numbers of HSPCs, splenomegaly, and extramedullary hematopoiesis. Differentiation in Cul5Vav-Cre mice is myeloid- and megakaryocyte-biased, resulting in leukocytosis, anemia and thrombocytosis. Cul5Vav-Cre mice increased HSC proliferation and circulation, associated with a decrease in CXCR4 surface expression. In bone marrow cells, we identified LRRC41 co-immunoprecipitated with CUL5, and vice versa, supporting that CRL5 forms a complex with LRRC41. We identified an accumulation of LRRC41 and STAT5 in Cul5Vav-Cre HSCs during IL-3 stimulation, supporting their regulation by Cul5. Whole cell proteome (WCP) analysis of HSPCs from Cul5Vav-Cre bone marrow identified upregulation of many STAT5 target genes and associated pathways. Finally, JAK1/2 inhibition with ruxolitinib normalized hematopoiesis in Cul5Vav-Cre mice. These studies demonstrate the function of Cul5 in HSC function, stem cell fate decisions, and regulation of IL-3 signaling.

Authors

Siera A. Tomishima, Dale D. Kim, Nadia Porter, Ipsita Guha, Asif A. Dar, Yohaniz Ortega-Burgos, Jennifer Roof, Hossein Fazelinia, Lynn A. Spruce, Christopher S. Thom, Robert L. Bowman, Paula M. Oliver

Dynamics of Th1/Th17 responses and antimicrobial pathways in leprosy skin lesions

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Abstract

BACKGROUND. Reversal reactions (RR) in leprosy are acute immune episodes marked by inflammation and bacterial clearance, offering a model to study the dynamics of host responses to Mycobacterium leprae. These episodes are often severe and difficult to treat, frequently progressing to permanent disabilities. We aimed to characterize the immune mechanisms and identify antimicrobial effectors during RR. METHODS. We performed RNA sequencing on paired skin biopsy specimens from nine leprosy patients collected before and at RR diagnosis, followed by differential gene expression and functional analysis. A machine learning classifier was applied to predict membrane-permeabilizing proteins. Antimicrobial activity was assessed in M. leprae-infected macrophages and axenic cultures. RESULTS. In the paired pre-RR and RR biopsy specimens, a 64-gene antimicrobial response signature was upregulated during RR and correlated with reduced M. leprae burden. Predicted upstream regulators included IL-1β, TNF, IFN-γ, and IL-17, indicating activation of both Th1 and Th17 pathways. A machine learning classifier identified 28 genes with predicted membrane-permeabilizing antimicrobial activity, including S100A8. Four proteins (S100A7, S100A8, CCL17, CCL19) demonstrated antimicrobial activity against M. leprae in vitro. Scanning electron microscopy revealed membrane damage in bacteria exposed to these proteins. CONCLUSION. RR is associated with a robust antimicrobial gene program regulated by Th1/Th17 cytokines. We identified potentially novel host antimicrobial effectors that exhibit activity against M. leprae, suggesting potential strategies to bolster Th1/Th17 responses for combating intracellular mycobacterial infections. FUNDING. NIH grants R01 AI022553, R01 AR040312, R01 AR073252, R01 AI166313, R01 AI169526, P50 AR080594, 4R37 AI052453-21, and NSF grant DMR2325840.

Authors

Priscila R. Andrade, Feiyang Ma, Jing Lu, Jaime de Anda, Ernest Y. Lee, George W. Agak, Craig J. Dobry, Bruno J. de Andrade Silva, Rosane M.B. Teles, Lilah A. Mansky, Jonathan Perrie, Dennis J. Montoya, Bryan D. Bryson, Johann E. Gudjonsson, Gerard C.L. Wong, Euzenir N. Sarno, Matteo Pellegrini, Robert L. Modlin

Nemo-like kinase disrupts nuclear import and drives TDP43 mislocalization in ALS

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Abstract

Cytoplasmic TDP43 mislocalization and aggregation are pathological hallmarks of amyotrophic lateral sclerosis (ALS). However, the initial cellular insults that lead to TDP43 mislocalization remain unclear. In this study, we demonstrate that Nemo-like kinase (NLK) — a proline-directed serine/threonine kinase — promotes the mislocalization of TDP43 and other RNA-binding proteins by disrupting nuclear import. NLK levels are selectively elevated in neurons exhibiting TDP43 mislocalization in ALS patient tissues, while genetic reduction of NLK reduces toxicity in human neuron models of ALS. Our findings suggest that NLK is a promising therapeutic target for neurodegenerative diseases.

Authors

Michael E. Bekier II, Emile S. Pinarbasi, Gopinath Krishnan, Jack J. Mesojedec, Madelaine Hurley, Harisankar Harikumar Sheela, Catherine A. Collins, Layla T. Ghaffari, Martina de Majo, Erik M. Ullian, Mark Koontz, Sarah Coleman, Xingli Li, Elizabeth M.H. Tank, Jacob Waksmacki, Fen-Biao Gao, Sami J. Barmada

BET inhibitors reduce tumor growth in preclinical models of gastrointestinal gene signature-positive castration-resistant prostate cancer

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A subgroup (~20-30%) of castration-resistant prostate cancer (CRPC) aberrantly expresses a gastrointestinal (GI) transcriptome governed by two GI-lineage-restricted transcription factors, HNF1A and HNF4G. In this study, we found that expression of GI transcriptome in CRPC correlates with adverse clinical outcomes to androgen receptor signaling inhibitor treatment and shorter overall survival. Bromo- and extra-terminal domain inhibitors (BETi) downregulated HNF1A, HNF4G, and the GI transcriptome in multiple CRPC models, including cell lines, patient-derived organoids, and patient-derived xenografts, while AR and the androgen-dependent transcriptome were largely spared. Accordingly, BETi selectively inhibited growth of GI transcriptome-positive preclinical models of prostate cancer. Mechanistically, BETi inhibited BRD4 binding at enhancers globally, including both AR and HNF4G bound enhancers while gene expression was selectively perturbed. Restoration of HNF4G expression in the presence of BETi rescued target gene expression without rescuing BRD4 binding. This suggests that inhibition of master transcription factors expression underlies the selective transcriptional effects of BETi.

Authors

Shipra Shukla, Dan Li, Woo Hyun Cho, Dana M. Schoeps, Holly M. Nguyen, Jennifer L. Conner, Marjorie L. Roskes, Anisha Tehim, Gabriella Bayshtok, Mohini R. Pachai, Juan Yan, Nicholas A. Teri, Eric Campeau, Sarah Attwell, Patrick Trojer, Irina Ostrovnaya, Anuradha Gopalan, Ekta Khurana, Eva Corey, Ping Chi, Yu Chen

Lung adenocarcinoma-derived IFN-γ promotes growth by modulating CD8+ T cell production of CCR5 chemokines

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Abstract

Since the lung is a mucosal barrier organ with a unique immunologic environment, mechanisms of immunoregulation in lung cancer may differ from those of other malignancies. Consistent with this notion, we found that CD8+ T cells play a paradoxical role in facilitating, rather than ameliorating, the growth of multiple lung adenocarcinoma models. These include spontaneous, carcinogen-induced, and transplantable tumor cell line models. Specifically, we found that CD8+ T cells promote homing of CD4+Foxp3+ T regulatory cells to the tumor bed by increasing levels of CCR5 chemokines in the tumor microenvironment in an IFN-γ and TNF-α dependent manner. Contrary to their canonical role, these Th1 cytokines contributed to accelerated growth of murine lung adenocarcinomas while suppressing the growth of other malignancies. Surprisingly, lung cancer cells themselves can serve as a dominant source of IFN-γ, and deletion of this cytokine from cancer cells using CRISPR/Cas-9 decreases tumor growth. Importantly for translational applications, a high level of IFN-γ was also found in human lung cancer patients at both the mRNA and protein level. Our data outlines what we deem a novel and previously undefined lung cancer specific immunoregulatory pathway that may be harnessed to tailor immune based therapy specifically for this malignancy.

Authors

Christina Kratzmeier, Mojtaba Taheri, Zhongcheng Mei, Isabelle Lim, May A. Khalil, Brandon Carter-Cooper, Rachel E. Fanaroff, Chin S. Ong, Eric B. Schneider, Stephanie Chang, Erica Leyder, Dongge Li, Irina G. Luzina, Anirban Banerjee, Alexander Sasha Krupnick

Biallelic variants in SREK1 downregulating SNORD115 and SNORD116 cause a Prader-Willi-like syndrome

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Abstract

Up to 10% of patients with severe early-onset obesity carry pathogenic variants in known obesity-related genes, mostly affecting the leptin-melanocortin pathway. Studying children with severe obesity from consanguineous populations provides a unique opportunity to uncover novel molecular mechanisms. Using whole-exome sequencing, followed by a rigorous analytical and filtration strategy, we identified three different homozygous missense variants in SREK1 (encoding Splicing Regulatory glutamic acid and lysine rich protein) in Pakistani children with severe obesity, from three unrelated consanguineous pedigrees. The wild type SREK1 gene of human induced pluripotent stem cell (iPSC)-derived hypothalamic neurons was individually replaced by each of the three variants and the impact of these changes on global gene expression was studied. Neurons expressing the two variants in the SREK1 RNA recognition domain p.P95L and p.T194M, but not the C-terminally located p.E601K, had markedly reduced expression of the small nucleolar RNA clusters SNORD115 and SNORD116, deficiency of which has been implicated in Prader-Willi syndrome (PWS). In addition to hyperphagic obesity the carriers of these two variants had other features of PWS, such as neonatal hypotonia. In conclusion, homozygous variants in SREK1 result in a subtype of severe early onset obesity sharing features with PWS.

Authors

Sadia Saeed, Anna-Maria Siegert, YC Loraine Tung, Roohia Khanam, Qasim M. Janjua, Jaida Manzoor, Mehdi Derhourhi, Bénédicte Toussaint, Brian Y. H. Lam, Sherine Awad, Emmanuel Vaillant, Emmanuel Buse Falay, Souhila Amanzougarene, Hina Ayesha, Waqas Imran Khan, Nosheen Ramzan, Vladimir Saudek, Stephen O'Rahilly, Anthony P. Goldstone, Muhammad Arslan, Amélie Bonnefond, Philippe Froguel, Giles S.H. Yeo

Sarcospan protects against LGMD R5 via remodeling of the sarcoglycan complex composition in dystrophic mice

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Abstract

The dystrophin-glycoprotein complex (DGC) is composed of peripheral and integral membrane proteins at the muscle cell membrane that link the extracellular matrix with the intracellular cytoskeleton. While it is well-established that genetic mutations that disrupt the structural integrity of DGC result in numerous muscular dystrophies, the three-dimensional structure of the complex has remained elusive. Two recent elegant cryoEM structures of DGC illuminate its molecular architecture and reveal the unique structural placement of sarcospan (SSPN) within the complex. SSPN, a 25-kDa tetraspanin-like protein, anchors beta-dystroglycan to the beta-, gamma- and delta-sarcoglycan trimer, supporting biochemical studies that SSPN is a core element for DGC assembly and stabilization. Here, we advance these studies by revealing that SSPN provides scaffolding in gamma-sarcoglycanopathies enabling substitution of gamma-sarcoglycan by its homolog, zeta-sarcoglycan, leading to the structural integrity of the DGC and prevention of limb-girdle muscular dystrophy R5. Three-dimensional modeling reveals that zeta-sarcoglycan preserves protein-protein interactions with the sarcospan, sarcoglycans, dystroglycan, and dystrophin. The structural integrity of the complex maintains myofiber attachment to the extracellular matrix and protect the cell membrane from contraction-induced damage. These findings demonstrate that sarcospan prevents limb-girdle muscular dystrophy R5 by remodeling of the sarcoglycan complex composition.

Authors

Ekaterina I. Mokhonova, Daniel Helzer, Ravinder Malik, Hafsa Mamsa, Jackson Walker, Mark Maslanka, Tess S. Fleser, Mohammad H. Afsharinia, Shiheng Liu, Johan Holmberg, Z. Hong Zhou, Eric J. Deeds, Kirk C. Hansen, Elizabeth M. McNally, Rachelle H. Crosbie

Angiopoietin-like protein 2 mediates vasculopathy driven fibrogenesis in a mouse model of systemic sclerosis

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Vasculopathy is a common hallmark of various fibrotic disorders including systemic sclerosis (SSc), yet its underlying etiology and contribution to fibrogenesis remain ill-defined. In SSc the vasculopathy typically precedes the onset of fibrosis and we observed that this phenomenon is recapitulated in the Snail transgenic mouse model of SSc. The vascular anomalies manifest as deformed vessels, endothelial cell dysfunction and vascular leakage. Our investigation into the underlying mechanism of this phenotype revealed that angiopoietin-like protein 2 (ANGPTL2), secreted by the Snail transgenic keratinocytes, is a principal driver of fibrotic vasculopathy. In endothelial cells, ANGPTL2 upregulates pro-fibrotic genes, downregulates various junctional proteins, and prompts the acquisition of mesenchymal characteristics. Inhibiting endothelial cell junctional instability and consequently vascular leakage with a synthetic analog of the microbial metabolite Urolithin A (UAS03) effectively mitigated the vasculopathy and inhibited fibrogenesis. Thus, ANGPTL2 emerges as a promising early biomarker of the disease and inhibiting the vasculopathy inducing effects of this protein with agents such as UAS03 presents an appealing therapeutic avenue to reduce disease severity. These insights hold the potential to revolutionize the approach to the treatment of fibrotic diseases by targeting the vascular defects.

Authors

Dyuti Saha, Ravi Kiran Annadorai, Sujaya Thannimangalath, Neha P. Shroff, Sunny Kataria, Binita Dam, Abhik Dutta, Akshay Hegde, Ankita Hiwale, Venkatesh Ravula, Shagnik Saha, Lekshmi Minikumari Rahulan, Neha Nigam, Neha Singh, Vikas Agarwal, Praveen K. Vemula, Colin Jamora

Neuraminidase 1 secondary deficiency contributes to CNS pathology in neurological mucopolysaccharidoses via brain proteins hypersialylation

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Abstract

Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III and VII, associated with lysosomal accumulation of heparan sulphate (HS), manifest with neurological deterioration and currently lack effective treatments. We report that neuraminidase 1 (NEU1) activity is drastically reduced in brain tissues of neurological MPS patients and mouse models but not in neurological lysosomal disorders without HS storage. Accumulated HS disrupts the lysosomal multienzyme complex of NEU1 with cathepsin A (CTSA), β-galactosidase (GLB1) and glucosamine-6-sulfate sulfatase (GALNS) leading to NEU1 deficiency and partial GLB1 and GALNS deficiencies in cortical tissues and iPSC-derived cortical neurons of neurological MPS patients. Increased sialylation of N-linked glycans in brains of MPS patients and mice implicated insufficient processing of sialylated glycans, except for polysialic acid. Correction of NEU1 activity in MPS IIIC mice by lentiviral gene transfer ameliorated previously identified hallmarks of the disease, including memory impairment, behavioural traits, and reduced levels of excitatory synapse markers VGLUT1 and PSD95. Overexpression of NEU1 also restored levels of VGLUT1/PSD95-positive puncta in cortical iPSC-derived MPS IIIA neurons. Our results demonstrate that HS-induced secondary NEU1 deficiency and aberrant sialylation of brain glycoproteins constitute what we believe to be a novel pathological pathway in neurological MPS spectrum crucially contributing to CNS pathology.

Authors

TianMeng Xu, Rachel Heon-Roberts, Travis Moore, Patricia Dubot, Xuefang Pan, Tianlin Guo, Christopher W. Cairo, Rebecca J. Holley, Brian Bigger, Thomas M. Durcan, Thierry Levade, Jerôme Ausseil, Bénédicte Amilhon, Alexei Gorelik, Bhushan Nagar, Shaukat Khan, Shunji Tomatsu, Luisa Sturiale, Angelo Palmigiano, Iris Röckle, Hauke Thiesler, Herbert Hildebrandt, Domenico Garozzo, Alexey V. Pshezhetsky

Cross-species efficacy of AAV-mediated ARSA replacement for Metachromatic Leukodystrophy

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Abstract

Metachromatic leukodystrophy (MLD) is an autosomal recessive neurodegenerative disorder caused by mutations in the arylsulfatase A (ARSA) gene, resulting in lower sulfatase activity and the toxic accumulation of sulfatides in the central and peripheral nervous system. Children account for 70% of cases and become progressively disabled with death occurring within 10 years of disease onset. Gene therapy approaches to restore ARSA expression via adeno-associated viral vectors (AAV) have been promising but hampered by limited brain biodistribution. We report the development of an engineered capsid AAV.GMU01, demonstrating superior biodistribution and transgene expression in the central nervous system of non-human primates (NHPs). Next, we show that AAV.GMU01-ARSA treated MLD mice exhibit persistent, normal levels of sulfatase activity and a concomitant reduction in toxic sulfatides. Treated mice also show a reduction in MLD-associated pathology and auditory dysfunction. Lastly, we demonstrate that treatment with AAV.GMU01-ARSA in NHPs is well-tolerated and results in potentially therapeutic ARSA expression in the brain. In summary, we propose AAV.GMU01-ARSA mediated gene replacement as a clinically viable approach to achieve broad and therapeutic levels of ARSA.

Authors

Shyam Ramachandran, Jeffery Ardinger, Jie Bu, MiAngela Ramos, Lilu Guo, Dhiman Ghosh, Mahmud Hossain, Shih-Ching Chou, Yao Chen, Erik Wischhof, Swathi Ayloo, Roger Trullo, Yuxia Luo, Jessica M. Hogestyn, Daniel M. DuBreuil, Emily Crosier, Johanna G. Flyer-Adams, Amy M. Richards, Michael Tsabar, Giorgio Gaglia, Shelley Nass, Bindu Nambiar, Denise Woodcock, Catherine O'Riordan, Qi Tang, Bradford Elmer, Bailin Zhang, Martin Goulet, Christian Mueller