Parathyroid hormone receptor (PTH1R) signaling mediates breast cancer metastasis to bone in mice

• Text
• PDF

Abstract

Bone metastases are a common complication of breast cancer. We have demonstrated that intermittent administration of parathyroid hormone (PTH [1-34]) reduces the incidence of bone metastases in murine models of breast cancer by acting on osteoblasts to alter the bone microenvironment. Here, we examined the role of PTH receptor (PTH1R)-mediated signaling in both osteoblasts and breast cancer cells in influencing bone metastases. In mice with impaired PTH1R signaling in osteoblasts, intermittent PTH did not reduce bone metastasis. Intermittent PTH also failed to reduce bone metastasis when expression of PTH1R was knocked down in 4T1 murine breast cancer cells by shRNA. In 4T1 breast cancer cells, PTH decreased expression of PTH-related protein (PTHrP), implicated in the vicious cycle of bone metastases. Knockdown of PTHrP in 4T1 cells significantly reduced migration towards MC3T3-E1 osteoblasts, and migration was further inhibited by treatment with intermittent PTH. Conversely, overexpression of PTHrP in 4T1 cells increased migration towards MC3T3-E1 osteoblasts and this was not inhibited by PTH. In conclusion, PTH1R expression is crucial in both osteoblasts and breast cancer cells for PTH to reduce bone metastases and in breast cancer cells this may be mediated in part by suppression of PTHrP.

Authors

Srilatha Swami, Hui Zhu, Aria Nisco, Takaharu Kimura, Matthew J. Kim, Vaisakh Nair, Joy Y. Wu

Origin, prospective identification, and function of circulating endothelial colony forming cells in mouse and man

• Text
• PDF

Abstract

Most circulating endothelial cells are apoptotic, but rare circulating endothelial colony forming cells (C-ECFCs, also known as blood outgrowth endothelial cells (BOECs)) with proliferative and vasculogenic activity can be cultured; the origin and naïve function of these C-ECFCs remains obscure. Herein, detailed lineage tracing reveals murine C-ECFCs emerge in the early postnatal period, display high vasculogenic potential, with enriched frequency of clonal proliferative cells compared to tissue-resident ECFCs, and are not committed to or derived from the bone marrow hematopoietic system but from tissue-resident ECFCs. In human subjects, C-ECFCs are present in the CD34bright cord blood mononuclear subset, possess proliferative potential and in vivo vasculogenic function in a naïve or cultured state, and display a single cell transcriptome sharing some umbilical venous endothelial cell features like, higher Protein C Receptor and extracellular matrix gene expression. This study provides an advance for the field by identifying the origin, naïve function, and antigens to prospectively isolate C-ECFCs for translational studies.

Authors

Yang Lin, Kimihiko Banno, Chang-Hyun Gil, Jered Myslinski, Takashi Hato, W. Christopher Shelley, Hongyu Gao, Xiaoling Xuei, Yunlong Liu, David Basile, Momoko Yoshimoto, Nutan Prasain, Stefan P Tarnawsky, Ralf H. Adams, Katsuhiko Naruse, Junko Yoshida, Michael P. Murphy, Kyoji Horie, Mervin C. Yoder

Release of STK24/25 suppression on MEKK3 signaling in endothelial cells confers Cerebral cavernous malformation

• Text
• PDF

Abstract

Loss of function mutations in CCM genes and gain of function mutation in the MAP3K3 gene encoding MEKK3 cause cerebral cavernous malformation (CCM). Deficiency of CCM proteins leads to the activation of MEKK3-KLF2/4 signaling, but it is not clear how this occurs. Here we demonstrate that deletion of the CCM3 interacting kinases STK24/25 in endothelial cells cause defects in vascular patterning during development as well as CCM lesion formation during postnatal life. While permanent deletion of STK24/25 in endothelial cells caused developmental defects of the vascular system, inducible postnatal deletion of STK24/25 impaired angiogenesis in the retina and brain. More importantly, deletion of STK24/25 in neonatal mice led to the development of severe CCM lesions. At the molecular level, a hybrid protein consisting of the STK kinase domain and the MEKK3 interacting domain of CCM2 rescued the vascular phenotype caused by the loss of ccm gene function in zebrafish. Our study suggests that CCM2/3 proteins act as adapters to allow recruitment of STK24/25 to limit the constitutive MEKK3 activity that contributes to vessel stability. Loss of STK24/25 causes MEKK3 activation leading to CCM lesion formation.

Authors

Xi Yang, Shi-Ting Wu, Rui Gao, Rui Wang, Yixuan Wang, Zhenkun Dong, Lu Wang, Chunxiao Qi, Xiaohong Wang, M. Lienhard Schmitz, Renjing Liu, Zhiming Han, Lu Wang, Xiangjian Zheng

Hypoxia enhances IPF mesenchymal progenitor cell fibrogenicity via the lactate/GPR81/HIF1α pathway

• Text
• PDF

Abstract

Hypoxia is a sentinel feature of IPF. The IPF microenvironment contains high lactate levels and hypoxia enhances cellular lactate production. Lactate, acting through the GPR81 lactate receptor, serves as a signal molecule regulating cellular processes. We previously identified intrinsically fibrogenic mesenchymal progenitor cells (MPCs) in the lungs of IPF patients that drive fibrosis. However, whether hypoxia enhances IPF MPC fibrogenicity is unclear. We hypothesized that hypoxia increases IPF MPC fibrogenicity via lactate and its cognate receptor GPR81. Here we show that hypoxia promotes IPF MPC self-renewal. The mechanism involves hypoxia-mediated enhancement of LDHA function and lactate production and release. Hypoxia also increases HIF1α levels, which in turn augments the expression of GPR81. Exogenous lactate operating through GPR81 promotes IPF MPC self-renewal. IHC analysis of IPF lung tissue demonstrate IPF MPCs expressing GPR81 and hypoxic markers on the periphery of the fibroblastic focus. We show that hypoxia enhances IPF MPC fibrogenicity in vivo. We demonstrate that knock-down of GPR81 inhibits hypoxia-induced IPF MPC self-renewal in vitro and attenuates hypoxia-induced IPF MPC fibrogenicity in vivo. Our data demonstrate that hypoxia creates a feed-forward loop that augments IPF MPC fibrogenicity via the lactate/GPR81/HIF1α pathway.

Authors

Libang Yang, Adam Gilbertsen, Hong Xia, Alexey Benyumov, Karen A. Smith, Jeremy A. Herrera, Emilian Racila, Peter B. Bitterman, Craig A. Henke

Impact of mechanical unloading on genome-wide DNA methylation profile of the failing human heart

• Text
• PDF

Abstract

Heart failure (HF) is characterized by global alterations in myocardial DNA methylation, yet little is known about epigenetic regulation of the non-coding genome and potential reversibility of DNA methylation with left ventricular assist device (LVAD) therapy. Genome-wide mapping of myocardial DNA methylation in 36 HF patients at LVAD implantation, 8 patients at LVAD explantation, and 7 non-failing donors using a high-density bead array platform identified 2079 differentially methylated positions (DMPs) in ischemic cardiomyopathy and 261 DMPs in non-ischemic cardiomyopathy. LVAD support resulted in normalization of only 3.2% of HF-associated DMPs. Methylation-expression correlation analysis yielded several protein-coding genes that are hypomethylated and upregulated (HTRA1, FBXO16, EFCAB13, AKAP13) or hypermethylated and downregulated (TBX3) in HF. A novel cardiac-specific super-enhancer lncRNA (LINC00881) is hypermethylated and downregulated in human HF. LINC00881 is an upstream regulator of sarcomere and calcium channel gene expression including MYH6, CACNA1C, and RYR2. LINC00881 knockdown reduces peak calcium amplitude in the beating human iPS cell derived cardiomyocytes. Collectively, these data suggest that HF-associated changes in myocardial DNA methylation within coding and non-coding genome are minimally reversible with mechanical unloading. Epigenetic reprogramming strategies may be necessary to achieve sustained clinical recovery from heart failure.

Authors

Xianghai Liao, Peter J. Kennel, Bohao Liu, Trevor R. Nash, Richard Z. Zhuang, Amandine F. Godier-Furnemont, Chenyi Xue, Rong Lu, Paolo C. Colombo, Nir Uriel, Muredach P. Reilly, Steven O. Marx, Gordana Vunjak-Novakovic, Veli K. Topkara

T follicular helper cells contribute to pathophysiology in a model of neuromyelitis optica spectrum disorders

• Text
• PDF

Abstract

Neuromyelitis optica spectrum disorders (NMOSD) are inflammatory autoimmune disorders of the CNS. Immunoglobulin G autoantibodies targeting the aquaporin-4 water channel (AQP4-IgG) are the pathogenic effector of NMOSD. Dysregulated T follicular helper (Tfh) cells have been implicated in the loss of B-cell tolerance in autoimmune diseases. The contribution of Tfh cells to disease activity and the therapeutic potential of targeting these cells in NMOSD remain unclear. Here, we established an autoimmune model of NMOSD by immunizing mice against AQP4 via in vivo electroporation. After AQP4 immunization, mice displayed AQP4 autoantibodies in the blood circulation, blood-brain barrier disruption, and IgG infiltration in the spinal cord parenchyma. Moreover, AQP4 immunization induced motor impairments and NMOSD-like pathologies including astrocytopathy, demyelination, axonal loss, and microglia activation. These were associated with increased splenic Tfh, T helper 1 (Th1) and T helper 17 (Th17) cells, memory B cells and plasma cell. AQP4-deficient mice did not displayed motor impairments and NMOSD-like pathologies after AQP4 immunization. Importantly, abrogating inducible costimulator (ICOS)/inducible costimulator ligand (ICOS-L) signalling using anti-ICOS-L antibody depleted Tfh cells and suppressed the response of Th1 and Th17 cells, memory B cells, and plasma cells in AQP4-immunized mice. These findings were associated with ameliorated motor impairments and spinal cord pathologies. This study suggests a role of Tfh cells in the pathophysiology of NMOSD in a novel mouse model with AQP4 autoimmunity. It also provides an animal model for further investigating the immunological mechanisms underlying AQP4 autoimmunity, and for developing novel therapeutic interventions targeting the autoimmune reactions in NMOSD.

Authors

Leung-Wah Yick, Oscar Ka-Fai Ma, Ethel Yin-Ying Chan, Krystal Xiwing Yau, Jason Shing-Cheong Kwan, Koon-Ho Chan

TFEB-mediated lysosomal exocytosis alleviates high fat diet–induced lipotoxicity in the kidney

• Text
• PDF

Abstract

Obesity is a major risk factor for end-stage kidney disease. We previously found that lysosomal dysfunction and impaired autophagic flux contributed to lipotoxicity in obesity-related kidney disease, both in humans and experimental animal models. However, the regulatory factors involved in countering renal lipotoxicity are largely unknown. Here we found that palmitic acid (PA) strongly promoted dephosphorylation and nuclear translocation of transcription factor EB (TFEB) by inhibiting the mechanistic target of rapamycin kinase complex 1 (MTORC1) pathway in a Rag GTPase–dependent manner, although these effects gradually diminished after extended treatment. We then investigated the role of TFEB in the pathogenesis of obesity-related kidney disease. Proximal tubular epithelial cell (PTEC)-specific Tfeb-deficient mice fed a high-fat diet (HFD) exhibited greater phospholipid accumulation in enlarged lysosomes, which manifested as multilamellar bodies (MLBs). Activated TFEB mediated lysosomal exocytosis of phospholipids, which help reduce MLB accumulation in PTECs. Furthermore, HFD-fed PTEC-specific Tfeb-deficient mice showed autophagic stagnation and exacerbated injury upon renal ischemia–reperfusion. Finally, higher body mass index was associated with increased vacuolation and decreased nuclear TFEB in the proximal tubules of chronic kidney disease patients. These results indicate a critical role of TFEB-mediated lysosomal exocytosis in counteracting renal lipotoxicity.

Authors

Jun Nakamura, Takeshi Yamamoto, Yoshitsugu Takabatake, Tomoko Namba-Hamano, Satoshi Minami, Atsushi Takahashi, Jun Matsuda, Shinsuke Sakai, Hiroaki Yonishi, Shihomi Maeda, Sho Matsui, Isao Matsui, Takayuki Hamano, Masatomo Takahashi, Maiko Goto, Yoshihiro Izumi, Takeshi Bamba, Miwa Sasai, Masahiro Yamamoto, Taiji Matsusaka, Fumio Niimura, Motoko Yanagita, Shuhei Nakamura, Tamotsu Yoshimori, Andrea Ballabio, Yoshitaka Isaka

Hyperprogression of cutaneous T cell lymphoma after anti-PD-1 treatment

• Text
• PDF

Abstract

BACKGROUND. Immune checkpoint blockade is an emerging treatment for T cell non-Hodgkin lymphoma (T-NHL), but some T-NHL patients have experienced hyperprogression with undetermined mechanisms upon anti-PD-1 therapy. METHODS. Single-cell RNA sequencing, whole-genome sequencing, whole-exome sequencing, and functional assays were performed on primary malignant T cells from a patient with advanced cutaneous T cell lymphoma, who experienced hyperprogression upon anti-PD-1 treatment. RESULTS. The patient was enrolled in a clinical trial of anti-PD-1 therapy and experienced disease hyperprogression. Single-cell RNA sequencing revealed that PD-1 blockade elicited a remarkable activation and proliferation of the CD4+ malignant T cells, which showed functional PD-1 expression and an exhausted status. Further analyses identified somatic amplification of PRKCQ in the malignant T cells. PRKCQ encodes PKCθ, a key player in the T cell activation/NF-kB pathway. PRKCQ amplification led to high expressions of PKCθ and p-PKCθ (T538) on the malignant T cells, resulting in an oncogenic activation of the T cell receptor (TCR) signaling pathway. PD-1 blockade in this patient released this signaling, de-repressed the proliferation of malignant T cells, and resulted in disease hyperprogression. CONCLUSIONS. Our study provides real-world clinical evidence that PD-1 acts as a tumor suppressor for malignant T cells with oncogenic TCR activation. TRIAL REGISTRATION. ClinicalTrials.gov (NCT03809767). FUNDING. The National Natural Science Foundation of China (81922058), the National Science Fund for Distinguished Young Scholars (T2125002), the National Science and Technology Major Project (2019YFC1315702), the National Youth Top-Notch Talent Support Program (283812), and the Peking University Clinical Medicine plus X Youth Project (PKU2019LCXQ012).

Authors

Yumei Gao, Simeng Hu, Ruoyan Li, Shanzhao Jin, Fengjie Liu, Xiangjun Liu, Yingyi Li, Yicen Yan, Weiping Liu, Jifang Gong, Shuxia Yang, Ping Tu, Lin Shen, Fan Bai, Yang Wang

Type I interferons link skin-associated dysbiotic commensal bacteria to pathogenic inflammation and angiogenesis in rosacea

• Text
• PDF

Abstract

Rosacea is a common chronic inflammatory skin disease with a fluctuating course of excessive inflammation and apparent neovascularization. Microbial dysbiosis with high density of B. oleronius and increased activity of kallikrein 5, which cleaves cathelicidin antimicrobial peptide, are key pathogenic triggers in rosacea. However, how these events are linked to the disease remains unknown. Here, we show that type I interferons produced by plasmacytoid dendritic cells represent the pivotal link between dysbiosis, the aberrant immune response, and neovascularization. Compared to other commensal bacteria, B. oleronius is highly susceptible and preferentially killed by cathelicidin antimicrobial peptides leading to enhanced generation of complexes with bacterial DNA. These bacterial DNA-complexes but not DNA-complexes derived from host cells are required for cathelicidin-induced activation of plasmacytoid dendritic cells and type I interferon production. Moreover, kallikrein 5 cleaves cathelicidin into peptides with heightened DNA-binding and type I interferon-inducing capacities. In turn, excessive type I interferon expression drives neoangiogenesis via IL22 induction and upregulation of the IL22 receptor on endothelial cells. These findings unravel a novel pathomechanism, which directly links hallmarks of rosacea to the killing of dysbiotic commensal bacteria with induction of a pathogenic type I interferon-driven and IL22-mediated angiogenesis.

Authors

Alessio A. Mylonas, Heike C. Hawerkamp, Yichen Wang, Jiaqi Chen, Francesco Messina, Olivier Demaria, Stephan Meller, Bernhard Homey, Jeremy Di Domizio, Lucia Mazzolai, Alain Hovnanian, Michel Gilliet, Curdin Conrad

A20 and the non-canonical NF-κB pathway are key regulators of neutrophil recruitment during fetal ontogeny

• Text
• PDF

Abstract

Newborns are at high risk of developing neonatal sepsis, particularly if born prematurely. This has been linked to divergent requirements the immune system has to fulfill during intrauterine compared to extrauterine life. By transcriptomic analysis of fetal and adult neutrophils we set out to shed new light on the molecular mechanisms of neutrophil maturation and functional adaption during fetal ontogeny. We identified an accumulation of differentially regulated genes within the non-canonical NF-κB signaling pathway accompanied by constitutive nuclear localization of RelB and increased surface expression of TNFRII in fetal neutrophils as well as elevated levels of LT-α in fetal serum. Furthermore, we found strong upregulation of the negative inflammatory regulator A20 (Tnfaip3) in fetal neutrophils, which was accompanied by a pronounced downregulation of the canonical NF-κB pathway. Functionally, overexpressing A20 in Hoxb8 cells led to reduced adhesion of these neutrophil-like cells under flow. Conversely, mice with a neutrophil specific A20 deletion displayed increased inflammation in vivo. Taken together, we have uncovered constitutive activation of the non-canonical NF-κB pathway with concomitant upregulation of A20 in fetal neutrophils. This offers perfect adaption of neutrophil function during intrauterine fetal life, but also restricts appropriate immune responses particularly in prematurely born infants.

Authors

Ina Rohwedder, Lou Martha Wackerbarth, Kristina Heinig, Annamaria Ballweg, Johannes Altstätter, Myriam Ripphahn, Claudia Nussbaum, Melanie Salvermoser, Susanne Bierschenk, Tobias Straub, Matthias Gunzer, Marc Schmidt-Supprian, Thomas Kolben, Christian Schulz, Averil Ma, Barbara Walzog, Matthias Heinig, Markus Sperandio