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TREM2 aggravates sepsis by inhibiting fatty acid oxidation via the SHP1/BTK axis

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Abstract

Impaired fatty acid oxidation (FAO) and the therapeutic benefits of FAO restoration have been revealed in sepsis. However, the regulatory factors contributing to FAO dysfunction during sepsis remain inadequately clarified. In this study, we identified a subset of lipid-associated macrophages characterized by high expression of trigger receptor expressed on myeloid cells 2 (TREM2) and demonstrated that TREM2 acted as a suppressor of FAO to increase the susceptibility to sepsis. TREM2 expression was markedly up-regulated in sepsis patients and correlated with the severity of sepsis. Knock out of TREM2 in macrophages improved the survival rate and reduced inflammation and organ injuries of sepsis mice. Notably, TREM2-deficient mice exhibited decreased triglyceride accumulation and an enhanced FAO rate. Further observations showed that the blockade of FAO substantially abolished the alleviated symptoms observed in TREM2 knockout mice. Mechanically, we demonstrated that TREM2 interacted with the phosphatase SHP1 to inhibit Bruton tyrosine kinas (BTK)-mediated FAO in sepsis. Our findings expand the understanding of FAO dysfunction in sepsis and reveal TREM2 as a critical regulator of FAO, which may provide a promising target for the clinical treatment of sepsis.

Authors

Siqi Ming, Xingyu Li, Qiang Xiao, Siying Qu, Qiaohua Wang, Qiongyan Fang, Pingping Liang, Yating Xu, Jingwen Yang, Yongqiang Yang, Xi Huang, Yongjian Wu

The Nr4a family regulates intrahepatic Treg proliferation and liver fibrosis in MASLD models

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Abstract

Nonalcoholic steatohepatitis (NASH) is a chronic progressive liver disease and highly prevalent worldwide. NASH is characterized by hepatic steatosis, inflammation, fibrosis and liver damage, which eventually results in liver dysfunction due to cirrhosis or hepatocellular carcinoma. However, the cellular and molecular mechanisms underlying NASH progression remain largely unknown. Here, we found an increase of Nr4a family of orphan nuclear receptors expression in intrahepatic T cells from mice with diet-induced NASH. Loss of Nr4a1 and Nr4a2 in T cell (dKO) ameliorated liver cell death and fibrosis, thereby mitigating liver dysfunction in NASH mice. dKO resulted in reduction of infiltrated macrophages and Th1/Th17 cells, whereas massive accumulation of T regulatory (Treg) cells in the liver of NASH mice. Combined single-cell RNA transcriptomic and TCR sequencing analysis revealed that intrahepatic dKO Tregs exhibited enhanced TIGIT and IL10 expression and were clonally expanded during NASH progression. Mechanistically, we found that dKO Tregs expressed high levels of Batf which promotes Treg cell proliferation and function upon TCR stimulation. Collectively, our findings not only provide an insight into the impact of intrahepatic Treg cells on NASH pathogenesis, but also suggest a therapeutic potential of targeting of Nr4a family to treat the disease.

Authors

Daisuke Aki, Taeko Hayakawa, Tanakorn Srirat, Shigeyuki Shichino, Minako Ito, Shin-Ichiroh Saitoh, Setsuko Mise-Omata, Akihiko Yoshimura

Adipocyte lipin 1 expression associates with human metabolic health and regulates systemic metabolism in mice

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Abstract

Dysfunctional adipose tissue is believed to promote the development of hepatic steatosis and systemic insulin resistance, but many of the mechanisms involved are still unclear. Lipin 1 catalyzes the conversion of phosphatidic acid to diacylglycerol (DAG), the penultimate step of triglyceride synthesis, which is essential for lipid storage. Herein we found that adipose tissue LPIN1 expression is decreased in people with obesity compared to lean subjects, and low LPIN1 expression correlated with multi-tissue insulin resistance and increased rates of hepatic de novo lipogenesis. Comprehensive metabolic and multi-omic phenotyping demonstrated that adipocyte-specific Lpin1–/– mice had a metabolically-unhealthy phenotype, including liver and skeletal muscle insulin resistance, hepatic steatosis, increased hepatic de novo lipogenesis, and transcriptomic signatures of metabolically associated steatohepatitis that was exacerbated by high-fat diets. We conclude that adipocyte lipin 1-mediated lipid storage is vital for preserving adipose tissue and systemic metabolic health, and its loss predisposes mice to metabolically associated steatohepatitis.

Authors

Andrew LaPoint, Jason M. Singer, Daniel Ferguson, Trevor M. Shew, M. Katie Renkemeyer, Hector H. Palacios, Rachael L. Field, Sireeesha Yerrathota, Roshan Kumari, Mahalakshmi Shankaran, Gordon I. Smith, Jun Yoshino, Mai He, Gary J. Patti, Marc K. Hellerstein, Samuel Klein, E. Matthew Morris, Jonathan R. Brestoff, Brian N. Finck, Andrew Lutkewitte

Transcription factor KROX20 marks epithelial stem cells for hair follicle formation

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Abstract

Epidermal stem cells control homeostasis and regeneration of skin and hair. In the hair follicle (HF) bulge of mammals, populations of slow-cycling stem cells regenerate the HF during cyclical rounds of anagen (growth), telogen (quiescence), and catagen (regression). Multipotent epidermal cells are also present in the HF above the bulge area, contributing to the formation and maintenance of sebaceous gland and upper and middle portions of the HF. Here, we report that the transcription factor Krox20 is enriched in an epidermal stem cell population located in the upper/ middle HF. Expression analyses and lineage tracing using inducible Krox20-CreERT showed that Krox20-lineage cells migrate out of this HF region and contribute to the formation of bulge in the HF, serving as ancestors of bulge stem cells. In vivo depletion of these cells arrests HF morphogenesis. This study identifies a novel marker for an epidermal stem cell population that is indispensable for hair homeostasis.

Authors

Elnaz Ghotbi, Edem Tchegnon, Zhiguo Chen, Stephen Li, Tracey Shipman, Yong Wang, Jenny Raman, Yumeng Zhang, Renee M. McKay, Chung-Ping Liao, Lu Q. Le

Reactive microglia partially envelop viable neurons in prion diseases

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Abstract

Microglia are recognized as the main cells in the central nervous system responsible for phagocytosis. The current study demonstrated that in prion disease, microglia effectively phagocytose prions or PrPSc during early preclinical stages. However, a critical shift occured in microglial activity during the late preclinical stage, transitioning from PrPSc uptake to establishing extensive neuron-microglia body-to-body cell contacts. This change was followed by a rapid accumulation of PrPSc in the brain. Microglia that enveloped neurons exhibited hypertrophic, cathepsin D-positive lysosomal compartments. However, most neurons undergoing envelopment were only partially encircled by microglia. Despite up to 40% of cortical neurons being partially enveloped at clinical stages, only a small percentage of envelopment proceeded to full engulfment. Partially enveloped neurons lacked apoptotic markers but showed signs of functional decline. Neuronal envelopment was independent of the CD11b pathway, previously associated with phagocytosis of newborn neurons during neurodevelopment. This phenomenon of partial envelopment was consistently observed across multiple prion-affected brain regions, various mouse-adapted strains, and different subtypes of sporadic Creutzfeldt-Jakob disease (sCJD) in humans. The current work describes a new phenomenon of partial envelopment of neurons by reactive microglia in the context of an actual neurodegenerative disease, not a disease model.

Authors

Natallia Makarava, Tarek Safadi, Olga Bocharova, Olga Mychko, Narayan P. Pandit, Kara Molesworth, Simone Baiardi, Li Zhang, Piero Parchi, Ilia V. Baskakov

Neutrophil-specific Shp1 loss results in lethal pulmonary hemorrhage in mouse models of acute lung injury

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Abstract

The acute respiratory distress syndrome (ARDS) is associated with significant morbidity and mortality and neutrophils are critical to its pathogenesis. Neutrophil activation is closely regulated by inhibitory tyrosine phosphatases including Src homology region 2 domain containing phosphatase-1 (Shp1). Here, we report that loss of neutrophil Shp1 in mice produced hyperinflammation and lethal pulmonary hemorrhage in sterile inflammation and pathogen-induced models of acute lung injury (ALI) through a Syk kinase-dependent mechanism. We observed large intravascular neutrophil clusters, perivascular inflammation, and excessive neutrophil extracellular traps in neutrophil-specific Shp1 knockout mice suggesting an underlying mechanism for the observed pulmonary hemorrhage. Targeted immunomodulation through the administration of a Shp1 activator (SC43) reduced agonist-induced reactive oxygen species in vitro and ameliorated ALI-induced alveolar neutrophilia and NETs in vivo. We propose that the pharmacologic activation of Shp1 has the potential to fine-tune neutrophil hyperinflammation that is central to the pathogenesis of ARDS.

Authors

S. Farshid Moussavi-Harami, Simon J. Cleary, Mélia Magnen, Yurim Seo, Catharina Conrad, Bevin C. English, Longhui Qiu, Kristin M. Wang, Clare L. Abram, Clifford A. Lowell, Mark R. Looney

Endothelial YAP/TAZ activation promotes atherosclerosis in a mouse model of Hutchinson-Gilford progeria syndrome

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Abstract

Hutchinson-Gilford progeria syndrome (HGPS) is an extremely rare disease caused by the expression of progerin, an aberrant protein produced by a point mutation in the LMNA gene. HGPS patients show accelerated aging and die prematurely mainly from complications of atherosclerosis such as myocardial infarction, heart failure, or stroke. However, the mechanisms underlying HGPS vascular pathology remain ill defined. We used single-cell RNA sequencing to characterize the aorta in progerin-expressing LmnaG609G/G609G mice and wild-type controls, with a special focus on endothelial cells (ECs). HGPS ECs showed gene expression changes associated with extracellular matrix alterations, increased leukocyte extravasation, and activation of the yes-associated protein 1/transcriptional activator with PDZ-binding domain (YAP/TAZ) mechanosensing pathway, all validated by different techniques. Atomic force microscopy experiments demonstrated stiffer subendothelial extracellular matrix in progeroid aortas, and ultrasound assessment of live HGPS mice revealed disturbed aortic blood flow, both key inducers of the YAP/TAZ pathway in ECs. YAP/TAZ inhibition with verteporfin reduced leukocyte accumulation in the aortic intimal layer and decreased atherosclerosis burden in progeroid mice. Our findings identify endothelial YAP/TAZ signaling as a key mechanism of HGPS vascular disease and open a new avenue for the development of YAP/TAZ targeting drugs to ameliorate progerin-induced atherosclerosis.

Authors

Ana Barettino, Cristina González-Gómez, Pilar Gonzalo, María J. Andrés-Manzano, Carlos R. Guerrero, Francisco M. Espinosa, Rosa M. Carmona, Yaazan Blanco, Beatriz Dorado, Carlos Torroja, Fátima Sánchez-Cabo, Ana Quintas, Alberto Benguría, Ana Dopazo, Ricardo García, Ignacio Benedicto, Vicente Andrés

Dual targeting macrophages and microglia is a therapeutic vulnerability in models of PTEN-deficient glioblastoma

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Abstract

Tumor-associated macrophages and microglia (TAMs) are critical for tumor progression and therapy resistance in glioblastoma (GBM), a type of incurable brain cancer. We previously identified lysyl oxidase (LOX) and olfactomedin like-3 (OLFML3) as essential macrophage and microglia chemokines, respectively, in GBM. Here, single-cell transcriptomics and multiplex sequential immunofluorescence followed by functional studies demonstrate that macrophages negatively correlate with microglia in the GBM tumor microenvironment. LOX inhibition in PTEN-deficient GBM cells upregulates OLFML3 expression via the NF-κB-PATZ1 signaling pathway, inducing a compensatory increase of microglia infiltration. Dual targeting macrophages and microglia via inhibition of LOX and the CLOCK-OLFML3 axis generates potent anti-tumor effects and offers a complete tumor regression in more than 60% of animals when combined with anti-PD1 therapy in PTEN-deficient GBM mouse models. Thus, our findings provide a translational triple therapeutic strategy for this lethal disease.

Authors

Yang Liu, Junyan Wu, Hinda Najem, Yiyun Lin, Lizhi Pang, Fatima Khan, Fei Zhou, Heba Ali, Amy B. Heimberger, Peiwen Chen

Neuropilin-2 expressing cells in breast cancer are S-nitrosylation hubs that mitigate radiation-induced oxidative stress

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Abstract

The high rate of recurrence after radiation therapy in triple-negative breast cancer (TNBC) indicates that novel approaches and targets are needed to enhance radiosensitivity. Here, we report that neuropilin-2 (NRP2), a receptor for vascular endothelial growth factor (VEGF) that is enriched on sub-populations of TNBC cells with stem cell properties, is an effective therapeutic target for sensitizing TNBC to radiotherapy. Specifically, VEGF/NRP2 signaling induces nitric oxide synthase 2 (NOS2) transcription by a mechanism dependent on Gli1. NRP2-expressing tumor cells serve as a hub to produce nitric oxide (NO), an autocrine and paracrine signaling metabolite, which promotes cysteine-nitrosylation of Kelch-like ECH-asssociated protein 1 (KEAP1) and, consequently, nuclear factor erythroid 2-related factor 2 (NFE2L2)-mediated transcription of antioxidant response genes. Inhibiting VEGF binding to NRP2, using a humanized monoclonal antibody (mAb), results in NFE2L2 degradation via KEAP1 rendering cell lines and organoids vulnerable to irradiation. Importantly, treatment of patient-derived xenografts with the NRP2 mAb and radiation resulted in significant tumor necrosis and regression compared to radiation alone. Together, these findings reveal a targetable mechanism of radioresistance and they support the use of NRP2 mAb as an effective radiosensitizer in TNBC.

Authors

Ayush Kumar, Hira Goel, Christi Wisniewski, Tao Wang, Yansong Geng, Mengdie Wang, Shivam Goel, Kai Hu, Rui Li, Lihua J. Zhu, Jennifer L. Clark, Lindsay M. Ferreira, Michael Brehm, Thomas J. Fitzgerald, Arthur M. Mercurio

YTHDF1 loss in dendritic cells potentiates radiation-induced antitumor immunity via STING-dependent type I IFN production

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Abstract

RNA N6-methyladenosine (m6A) reader YTHDF1 is implicated in cancer etiology and progression. We discovered that radiotherapy (RT) increased YTHDF1 expression in dendritic cells (DCs) of PBMCs from cancer patients, but not in other immune cells tested. Elevated YTHDF1 expression of DCs was associated with poor outcomes in patients receiving RT. We found that loss of Ythdf1 in DCs enhanced the antitumor effects of ionizing radiation (IR) via increasing the cross-priming capacity of DCs across multiple murine cancer models. Mechanistically, IR upregulated YTHDF1 expression in DCs through STING-IFN-I signaling. YTHDF1 in turn triggered STING degradation by increasing lysosomal cathepsins, thereby reducing IFN-I production. We created a YTHDF1 deletion/inhibition prototype DC vaccine, significantly improving the therapeutic effect of RT and radio-immunotherapy in a murine melanoma model. Our findings reveal a new layer of regulation between YTHDF1/m6A and STING in response to IR, which opens new paths for the development of YTHDF1-targeting therapies.

Authors

Chuangyu Wen, Liangliang Wang, András Piffkó, Dapeng Chen, Xianbin Yu, Katarzyna Zawieracz, Jason Bugno, Kaiting Yang, Emile Z. Naccasha, Fei Ji, Jiaai Wang, Xiaona Huang, Stephen Y. Luo, Lei Tan, Bin Shen, Cheng Luo, Megan E. McNerney, Steven J. Chmura, Ainhoa Arina, Sean P. Pitroda, Chuan He, Hua Liang, Ralph R. Weichselbaum

TSC/mTORC1 mediates mTORC2/AKT1 signaling in c-MYC-induced murine hepatocarcinogenesis via centromere protein M

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Abstract

Activated mTORC2/AKT signaling plays a role in hepatocellular carcinoma (HCC). Research has shown that TSC/mTORC1 and FOXO1 are distinct downstream effectors of AKT signaling in liver regeneration and metabolism. However, the mechanisms by which these pathways mediate mTORC2/AKT activation in HCC are not yet fully understood. Amplification and activation of c-MYC is a key molecular event in HCC. In this study, we explored the roles of TSC/mTORC1 and FOXO1 as downstream effectors of mTORC2/AKT1 in c-MYC-induced hepatocarcinogenesis. Using various genetic approaches in mice, we found that manipulating the FOXO pathway had minimal impact on c-MYC-induced HCC. In contrast, loss of mTORC2 inhibited c-MYC-induced HCC, an effect that was completely reversed by ablating TSC2, which activated mTORC1. Additionally, we discovered that p70/RPS6 and 4EBP1/eIF4E act downstream of mTORC1, regulating distinct molecular pathways. Notably, the 4EBP1/eIF4E cascade is crucial for cell proliferation and glycolysis in c-MYC-induced HCC. We also identified centromere protein M (CENPM) as a downstream target of the TSC2/mTORC1 pathway in c-MYC-driven hepatocarcinogenesis, and its ablation entirely inhibited c-MYC-dependent HCC formation. Our findings demonstrate that the TSC/mTORC1/CENPM pathway, rather than the FOXO cascade, is the primary signaling pathway regulating c-MYC-driven hepatocarcinogenesis. Targeting CENPM holds therapeutic potential for treating c-MYC-driven HCC.

Authors

Yi Zhou, Shu Zhang, guoteng Qiu, Xue Wang, Andrew Yonemura, Hongwei Xu, Guofei Cui, Shanshan Deng, Joanne Chun, Nianyong Chen, Meng Xu, Xinhua Song, Jingwen Wang, Zijing Xu, Youping Deng, Matthias Evert, Diego F. Calvisi, Shumei Lin, Haichuan Wang, Xin Chen

Innate immune cell activation by adjuvant AS01 in human lymph node explants is age-independent

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Abstract

Vaccine adjuvants are thought to work by stimulating innate immunity in the draining lymph node (LN), although this has not been proven in humans. To bridge data obtained in animals to humans, we have developed an in situ human LN explant model to investigate how adjuvants initiate immunity. Slices of explanted LNs were exposed to vaccine adjuvants and revealed responses that were not detectable in LN cell suspensions. We used this model to compare the liposome-based AS01 with its components MPL and QS-21, and TLR ligands. Liposomes were predominantly taken up by subcapsular sinus-lining macrophages, monocytes and dendritic cells. AS01 induced dendritic cell maturation and a strong pro-inflammatory cytokine response in intact LN slices but not in dissociated cell cultures, in contrast to R848. This suggests the onset of the immune response to AS01 requires a coordinated activation of LN cells in time and space. Consistent with the robust immune response observed in older adults with AS01-adjuvanted vaccines, the AS01 response in human LNs was independent of age, unlike R848. This human LN explant model is a valuable tool for studying the mechanism of action of adjuvants in humans and for screening new formulations to streamline vaccine development.

Authors

Vicki V. Stylianou, Kirstie M. Bertram, Van Anh Vo, Elizabeth B. Dunn, Heeva Baharlou, Darcii J. Terre, James Elhindi, Elisabeth Elder, James French, Farid Meybodi, Stéphane T. Temmerman, Arnaud M. Didierlaurent, Margherita Coccia, Kerrie J. Sandgren, Anthony L. Cunningham

Pharmacological regeneration of sensory hair cells restores afferent innervation and vestibular function

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Abstract

The sensory cells that transduce the signals for hearing and balance are highly specialized mechanoreceptors called hair cells that reside in the sensory epithelia of the inner ear. Loss of hair cells from toxin exposure and age can cause balance disorders and is essentially irreversible due to the inability of mammalian vestibular organs to regenerate physiologically active hair cells. Here, we show substantial regeneration of hair cells in a mouse model of vestibular damage by treatment with a combination of glycogen synthase kinase 3β and histone deacetylase inhibitors. The drugs stimulated supporting cell proliferation and differentiation into hair cells. The new hair cells were reinnervated by vestibular afferent neurons, rescuing otolith function by restoring head translation-evoked otolith afferent responses and vestibuloocular reflexes. Drugs that regenerate hair cells thus represent a potential therapeutic approach to the treatment of balance disorders.

Authors

Hanae Lahlou, Hong Zhu, Wu Zhou, Albert S.B. Edge

Proteogenomic analysis integrated with electronic health records data reveals disease-associated variants in Black Americans

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Abstract

BACKGROUND. Most genome wide association studies (GWAS) of plasma proteomics have focused on White individuals of European ancestry, limiting biological insight from other ancestry enriched protein quantitative loci (pQTL). METHODS. We conducted a discovery GWAS of ~3,000 plasma proteins measured by the antibody based Olink platform in 1,054 Black adults from the Jackson Heart Study (JHS), and validated our findings in the Multi-Ethnic Study of Atherosclerosis (MESA). The genetic architecture of identified pQTLs were further explored through fine mapping and admixture association analysis. Finally, using our pQTL findings, we performed a phenome wide association study (PheWAS) across two large multi-ethnic electronic health record (EHR) systems in All of Us and BioMe. RESULTS. We identified 1002 pQTLs for 925 proteins. Fine mapping and admixture analyses suggested allelic heterogeneity of the plasma proteome across diverse populations. We identified associations for variants enriched in African ancestry, many in diseases that lack precise biomarkers, including cis-pQTLs for Cathepsin L (CTSL) and Siglec-9 that were linked with sarcoidosis and non-Hodgkin’s lymphoma, respectively. We found concordant associations across clinical diagnoses and laboratory measurements, elucidating disease pathways, including a cis-pQTL associated with circulating CD58, white blood cell count, and multiple sclerosis. CONCLUSIONS. Our findings emphasize the value of leveraging diverse populations to enhance biological insights from proteomics GWAS, and we have made this resource readily available as an interactive web portal.

Authors

Usman A. Tahir, Jacob L. Barber, Daniel E. Cruz, Meltem Ece Kars, Shuliang Deng, Bjoernar Tuftin, Madeline G. Gillman, Mark D. Benson, Jeremy M. Robbins, Zsu-Zsu Chen, Prashant Rao, Daniel H. Katz, Laurie Farrell, Tamar Sofer, Michael E. Hall, Lynette Ekunwe, Russell P. Tracy, Peter Durda, Kent D. Taylor, Yongmei Liu, W. Craig Johnson, Xiuqing Guo, Yii-Der Ida Chen, Ani W. Manichaikul, Deepti Jain, Thomas J. Wang, Alex P. Reiner, Pradeep Natarajan, Yuval Itan, Stephen S. Rich, Jerome I. Rotter, James G. Wilson, Laura M. Raffield, Robert E. Gerszten

Modeling primary microcephaly with human brain organoids reveals fundamental roles of CIT kinase activity

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Abstract

Brain size and cellular heterogeneity are tightly regulated by species-specific proliferation and differentiation of multipotent neural progenitor cells (NPCs). Errors in this process are among the mechanisms of primary hereditary microcephaly (MCPH), a group of disorders characterized by reduced brain size and intellectual disability. Biallelic CIT missense variants that disrupt kinase function (CITKI/KI) and frameshift loss-of-function variants (CITFS/FS) are the genetic basis for MCPH17; however, the function of CIT catalytic activity in brain development and NPC cytokinesis is unknown. Therefore, we created the CitKI/KI mouse model and found that it does not phenocopy human microcephaly, unlike biallelic CitFS/FS animals. Nevertheless, both Cit models exhibited binucleation, DNA damage, and apoptosis. To investigate human-specific mechanisms of CIT microcephaly, we generated CITKI/KI and CITFS/FS human forebrain organoids. We found that CITKI/KI and CITFS/FS organoids lose cytoarchitectural complexity, transitioning from pseudostratified to simple neuroepithelium. This change was associated with defects that disrupt polarity of NPC cytokinesis, in addition to elevating apoptosis. Together, our results indicate that both CIT catalytic and scaffolding functions in NPC cytokinesis are critical for human corticogenesis. Species differences in corticogenesis and the dynamic 3D features of NPC mitosis underscore the utility of human forebrain organoid models for understanding human microcephaly.

Authors

Gianmarco Pallavicini, Amanda Moccia, Giorgia Iegiani, Roberta Parolisi, Emily R. Peirent, Gaia Elena Berto, Martina Lorenzati, Rami Y. Tshuva, Alessia Ferraro, Fiorella Balzac, Emilia Turco, Shachi U. Salvi, Hedvig F. Myklebust, Sophia Wang, Julia Eisenberg, Maushmi Chitale, Navjit S. Girgla, Enrica Boda, Orly Reiner, Annalisa Buffo, Ferdinando Di Cunto, Stephanie L. Bielas

Stimulation of an entorhinal-hippocampal extinction circuit facilitates fear extinction in a post-traumatic stress disorder model

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Abstract

Effective psychotherapy of post-traumatic stress disorder (PTSD) remains challenging due to the fragile nature of fear extinction, for which ventral hippocampal CA1 (vCA1) region is considered as a central hub. However, neither the core pathway nor the cellular mechanisms involved in implementing extinction are known. Here, we unveil a direct pathway, where layer 2a fan cells in the lateral entorhinal cortex (LEC) target parvalbumin-expressing interneurons (PV-INs) in the vCA1 region to propel low gamma-band synchronization of the LEC-vCA1 activity during extinction learning. Bidirectional manipulations of either hippocampal PV-INs or LEC fan cells sufficed fear extinction. Gamma entrainment of vCA1 by deep brain stimulation (DBS) or noninvasive transcranial alternating current stimulation (tACS) of LEC persistently enhanced the PV-IN activity in vCA1, thereby promoting fear extinction. These results demonstrate that the LEC-vCA1 pathway forms a top-down motif to empower low gamma-band oscillations that facilitate fear extinction. Finally, application of low gamma DBS and tACS to a mouse model with persistent PTSD showed potent efficacy, suggesting that the dedicated LEC-vCA1 pathway can be stimulated for therapy to remove traumatic memory trace.

Authors

Ze-Jie Lin, Xue Gu, Wan-Kun Gong, Mo Wang, Yan-Jiao Wu, Qi Wang, Xin-Rong Wu, Xin-Yu Zhao, Michael X. Zhu, Lu-Yang Wang, Quanying Liu, Ti-Fei Yuan, Wei-Guang Li, Tian-Le Xu

Egfl6 promotes ovarian cancer progression by enhancing the immunosuppressive functions of tumor-associated myeloid cells

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Abstract

Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play a critical role in resistance to immunotherapy. In this study, we identified epidermal growth factor-like 6 (Egfl6) as a new regulator of myeloid cell functions. Our analyses indicated that Egfl6, via binding with β3 integrins and activation of p38 and SYK signaling, acts as a chemotactic factor for myeloid cells migration and promotes their differentiation towards an immunosuppressive state. In syngeneic mouse models of ovarian cancer (OvCa), tumor expression of Egfl6 increased the intra-tumoral accumulation of polymorphonuclear (PMN) MDSCs and TAMs and their expression of immunosuppressive factors, including CXCL2, IL-10 and PD-L1. Consistent with this, in an immune ‘hot’ tumor model, Egfl6 expression eliminated response to a-PD-L1 therapy, while Egfl6 neutralizing antibody decreased the accumulation of tumor-infiltrating CD206+ TAMs and PMN-MDSCs and restored the efficacy of a-PD-L1 therapy. Supporting a role in human tumors, in human OvCa tissue samples, areas of high EGFL6 expression co-localized with myeloid cell infiltration. scRNAseq analyses revealed a correlation between EGFL6 and immune cell expression of immunosuppressive factors. Our data provide mechanistic insights into the onco-immunologic functions of EGFL6 in mediating tumor immune suppression and identified EGFL6 as a potential novel therapeutic target to enhance immunotherapy in OvCa patients.

Authors

Sarah Hamze Sinno, Joshua A. Imperatore, Shoumei Bai, Noémie Gomes-Jourdan, Nyasha Mafarachisi, Claudia Coronnello, Linan Zhang, Eldin Jašarević, Hatice U. Osmanbeyoglu, Ronald J. Buckanovich, Sandra Cascio

Long-lived lung megakaryocytes contribute to platelet recovery in thrombocytopenia models

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Abstract

Lung megakaryocytes (Mks) are largely extravascular with an immune phenotype (1). Because bone marrow (BM) Mks are short-lived it has been assumed that extravascular lung Mks are constantly ‘seeded’ from the BM. To investigate lung Mk origins and how that impacts their functions, we developed methods to specifically label lung Mks using CFSE dye and biotin delivered oropharyngeal. Labeled lung Mks were present for up to four months, while BM Mks had a <1 week lifespan. In a parabiosis model, lung Mks were partially replaced over 1-month from a circulating source. Unlike tissue-resident macrophages, using MDS1-Cre-ERT2 TdTomato mice, we found that lung Mks arise from hematopoietic stem cells. However, studies with FlkSwitch mTmG mice showed that lung Mks are derived from a Flt3-independent lineage that does not go through a multipotent progenitor. CFSE labeling to track lung Mk-derived platelets showed that about 10% of circulating platelets are lung resident Mk-derived at steady state, but in sterile thrombocytopenia this was doubled (about 20%). Lung-derived platelets were similarly increased in a malaria infection model (Plasmodium yoelii) typified by thrombocytopenia. These studies indicate that lung Mks arise from a Flt3-negative BM source, are long-lived, and contribute more platelets during thrombocytopenia.

Authors

Alison C. Livada, Kathleen E. McGrath, Michael W. Malloy, Chen Li, Sara K. Ture, Paul D. Kingsley, Anne D. Koniski, Leah A. Vit, Katherine E. Nolan, Deanne Mickelsen, Grace E. Monette, Preeti Maurya, James Palis, Craig N. Morrell

CRISPR–Cas13d targeting suppresses repeat-associated non-AUG translation of C9orf72 hexanucleotide repeat RNA

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Abstract

A hexanucleotide GGGGCC repeat expansion in the non-coding region of C9orf72 gene is the most common genetic mutation identified in patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The resulting repeat RNA and dipeptide repeat proteins from non-conventional repeat translation have been recognized as important markers associated with the diseases. CRISPR-Cas13d, a powerful RNA targeting tool, has faced challenges in effectively targeting RNA with stable secondary structures. Here we report that CRISPR-Cas13d can be optimized to specifically target GGGGCC repeat RNA. Our results demonstrate that the CRISPR-Cas13d system can be harnessed to significantly diminish the translation of poly-dipeptides originating from the GGGGCC repeat RNA. This efficacy has been validated in various cell types, including induced pluripotent stem cells and differentiated motor neurons originating from C9orf72-ALS patients, as well as in C9orf72 repeat transgenic mice. These findings demonstrate the application of CRISPR-Cas13d in targeting RNA with intricate higher-order structures and suggest a potential therapeutic approach for ALS and FTD.

Authors

Honghe Liu, Xiao-Feng Zhao, Yu-Ning Lu, Lindsey R. Hayes, Jiou Wang

Natural TCRs targeting KRAS^G12V display fine specificity and sensitivity to human solid tumors

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Abstract

BACKGROUND. Neoantigens derived from KRASMUT have been described, but the fine antigen specificity of T cell responses directed against these epitopes are poorly understood. Here, we explore KRASMUT immunogenicity and the properties of 4 TCRs specific for KRASG12V restricted to HLA-A3 superfamily of class I alleles. METHODS. A phase I clinical vaccine trial targeting KRASMUT was conducted. TCRs targeting KRASG12V restricted to HLA-A*03:01 or HLA-A*11:01 were isolated from vaccinated patients or healthy individuals. A comprehensive analysis of TCR antigen specificity, affinity, cross-reactivity, and CD8 coreceptor dependence was performed. TCR lytic activity was evaluated, and target antigen density was determined by quantitative immunopeptidomics. RESULTS. Vaccination against KRASMUT resulted in the priming of CD8+ and CD4+ T cell responses. KRASG12V -specific natural (not affinity-enhanced) TCRs exhibited exquisite specificity to mutated protein with no discernable reactivity against KRASWT. TCR-recognition motifs were determined and used to identify and exclude cross-reactivity to non-cognate peptides derived from the human proteome. Both HLA-A*03:01 and HLA-A*11:01 restricted TCR-redirected CD8+ T cells exhibited potent lytic activity against KRASG12V cancers, while only HLA-A*11:01 restricted TCR-T CD4+ T cells exhibited anti-tumor effector functions consistent with partial co-receptor dependence. All KRASG12V-specific TCRs displayed high sensitivity for antigen as demonstrated by their ability to eliminate tumor cell lines expressing low levels of of peptide/HLA (4.4 to 242) complexes per cell. CONCLUSION. This study identifies KRASG12V-specific TCRs with high therapeutic potential for the development of TCR-T cell therapies. TRIAL REGISTRATION. ClinicalTrials.gov NCT03592888. FUNDING. AACR SU2C / Lustgarten Foundation, Parker Institute for Cancer Immunotherapy, and NIH (R01 CA204261, P01 CA217805, P30 CA016520).

Authors

Adham S. Bear, Rebecca B. Nadler, Mark H. O'Hara, Kelsey L. Stanton, Chong Xu, Robert J. Saporito, Andrew J. Rech, Miren L. Baroja, Tatiana Blanchard, Maxwell H. Elliott, Michael J. Ford, Richard C. Jones, Shivang Patel, Andrea L. Brennan, Zachary O'Neil, Daniel J. Powell Jr., Robert H. Vonderheide, Gerald P. Linette, Beatriz M. Carreno