Severe lung damage in COVID-19 involves complex interactions between diverse populations of immune and stromal cells. In this study, we used a spatial transcriptomics approach to delineate the cells, pathways and genes present across the spectrum of histopathological damage in COVID-19 lung tissue. We applied correlation network-based approaches to deconvolve gene expression data from 46 areas of interest covering >62,000 cells within well preserved lung samples from three patients. Despite substantial inter-patient heterogeneity, we discovered evidence for a common immune cell signaling circuit in areas of severe tissue that involves crosstalk between cytotoxic lymphocytes and pro-inflammatory macrophages. Expression of IFNG by cytotoxic lymphocytes was associated with induction of chemokines including CXCL9, CXCL10 and CXCL11 which are known to promote the recruitment of CXCR3+ immune cells. The tumour necrosis factor (TNF) superfamily members BAFF (TNFSF13B) and TRAIL (TNFSF10) were found to be consistently upregulated in the areas with severe tissue damage. We used published spatial and single cell SARS-CoV-2 datasets to confirm our findings in the lung tissue from additional cohorts of COVID-19 patients. The resulting model of severe COVID-19 immune-mediated tissue pathology may inform future therapeutic strategies.
Amy R. Cross, Carlos E. de Andrea, María Villalba-Esparza, Manuel F. Landecho, Lucia Cerundolo, Praveen Weeratunga, Rachel E. Etherington, Laura Denney, Graham Ogg, Ling-Pei Ho, Ian S.D. Roberts, Joanna Hester, Paul Klenerman, Ignacio Melero, Stephen N. Sansom, Fadi Issa
Vascular smooth muscle cells (vSMC) exert a critical role in sensing and maintaining vascular integrity. These cells abundantly express the low-density lipoprotein receptor-related protein 1 (LRP1), a large endocytic and signaling receptor that recognizes numerous ligands including ApoE-rich lipoproteins, proteases, and protease-inhibitor complexes. We observed the spontaneous formation of aneurysms in the superior mesenteric artery (SMA) of both male and female mice in which LRP1 was genetically deleted in v SMC (smLRP1-/- mice). Quantitative proteomics revealed elevated abundance of several proteins in smLRP1-/- mice that are known to be induced by angiotensin II (AngII)-mediated signaling, suggesting that this pathway is dysregulated. Administration of losartan, an AngII type I receptor antagonist, or an angiotensinogen antisense oligonucleotide to reduce plasma angiotensinogen concentrations restored the normal SMA phenotype in smLRP1-/- mice and prevented aneurysm formation. Additionally, employing a vascular injury model, we noted excessive vascular remodeling and neointima formation in smLRP1-/- mice that was restored by losartan administration. Together, these findings reveal that LRP1 regulates vascular integrity and remodeling of the SMA by attenuating excessive AngII-mediated signaling.
Jackie M. Zhang, Dianaly T. Au, Hisashi Sawada, Michael K. Franklin, Jessica J. Moorleghen, Deborah A. Howatt, Pengjun Wang, Brittany O. Aicher, Brian Hampton, Mary Migliorini, Fenge Ni, Adam E. Mullick, Mashhood M. Wani, Areck A. Ucuzian, Hong S. Lu, Selen C. Muratoglu, Alan Daugherty, Dudley K. Strickland
Hepatocellular carcinoma (HCC) is the most common lethal form of liver cancer. Apart from surgical removal and transplantation, other treatments have not yet been well established for patients with HCC. Herein, we found that carboxylesterase 1 (CES1) was expressed at various levels in HCC. We further revealed that blockage of CES1 by pharmacological and genetical approaches leads to altered lipid profiles that are directly linked to impaired mitochondrial function. Mechanistically, LC-MS/MS and lipidomic analyses revealed that lipid signaling molecules, including polyunsaturated fatty acids (PUFAs), which activate PPARα/γ, were dramatically reduced upon CES1 inhibition. As a result, SCD, a PPARα/γ target gene involved in tumor progression and chemoresistance, was significantly downregulated. Consistently, clinical analysis demonstrated a strong correlation between the protein levels of CES1 and SCD in HCC. Interference with lipid signaling by targeting the “CES1-PPARα/γ-SCD” axis sensitized HCC cells to cisplatin treatment. As a demonstration, the growth of HCC xenograft tumors in NU/J mice was potently limited by co-administration of cisplatin and CES1 inhibition. Our results suggest that CES1 is a promising therapeutic target for HCC treatment.
Gang Li, Xin Li, Iqbal Mahmud, Jazmin Ysaguirre, Baharan Fekry, Shuyue Wang, Bo Wei, Kristin L. Eckel-Mahan, Philip L. Lorenzi, Richard Lehner, Kai Sun
Podocyte injury and loss are key drivers of primary and secondary glomerular diseases, such as focal segmental glomerulosclerosis (FSGS) and diabetic kidney disease (DKD). We previously demonstrated the renoprotective role of protein S (PS) and its cognate tyrosine-protein kinase receptor, TYRO3, in models of FSGS and DKD and that their signaling exerts anti-apoptotic and anti-inflammatory effects to confer protection against podocyte loss. Among the three TAM receptors (TYRO3, AXL, and MER), only TYRO3 expression is largely restricted to podocytes, and glomerular TYRO3 mRNA expression negatively correlates with human glomerular disease progression. We, therefore, posited that the agonism PS-TYRO3 signaling could serve as a potential therapeutic approach to attenuate glomerular disease progression. As PS function is not limited to TYRO3-mediated signal transduction but includes its anticoagulant activity, we focused on the development of TYRO3 agonist as an optimal therapeutic approach to glomerular disease. Among the small molecule TYRO3 agonist compounds screened, compound-10 (C-10) showed a select activation of TYRO3 without any effects on AXL or MER. We also confirmed that C-10 directly binds to TYRO3, but not the other receptors. In vivo, C-10 attenuated proteinuria, glomerular injury, and podocyte loss in mouse models of adriamycin-induced nephropathy and db/db model of type 2 diabetes. Moreover, these renoprotective effects of C-10 are lost in Tyro3 knockout mice, indicating that C-10 is a select agonist of TYRO3 activity that mitigates podocyte injury and glomerular disease. Therefore, C-10, a novel TYRO3 agonist, could be potentially developed as a new therapy for glomerular disease.
Fang Zhong, Hong Cai, Jia Fu, Zeguo Sun, Zhengzhe Li, David Bauman, Lois Wang, Bhaskar Das, Kyung Lee, John He
Dysfunction of alveolar epithelial type 2 cells (AEC2s), the facultative progenitors of lung alveoli, is implicated in pulmonary disease pathogenesis, highlighting the importance of human in vitro models. However, AEC2-like cells in culture have yet to be directly compared to their in vivo counterparts at single cell resolution. Here, we perform head-to-head comparisons between the transcriptomes of fresh primary (1o) adult human AEC2s, their cultured progeny, and human induced pluripotent stem cell-derived AEC2s (iAEC2s). We find each population occupies a distinct transcriptomic space with cultured AEC2s (1o and iAEC2s) exhibiting similarities to and differences from freshly purified 1o cells. Across each cell type, we find an inverse relationship between proliferative and maturation states, with pre-culture 1o AEC2s being most quiescent/mature and iAEC2s being most proliferative/least mature. Cultures of either type of human AEC2 do not generate detectable alveolar type 1 cells in these defined conditions; however, a subset of iAEC2s co-cultured with fibroblasts acquires a “transitional cell state” described in mice and humans to arise during fibrosis or following injury. Hence, we provide direct comparisons of the transcriptomic programs of 1o and engineered AEC2s, two in vitro models that can be harnessed to study human lung health and disease.
Konstantinos-Dionysios Alysandratos, Carolina Garcia-de-Alba, Changfu Yao, Patrizia Pessina, Jessie Huang, Carlos Villacorta-Martin, Olivia T. Hix, Kasey Minakin, Claire L. Burgess, Pushpinder Bawa, Aditi Murthy, Bindu Konda, Michael F. Beers, Barry R. Stripp, Carla F. Kim, Darrell N. Kotton
Understanding persistence and evolution of B cell clones after COVID-19 infection and vaccination is crucial for predicting responses against emerging viral variants and optimizing vaccines. Here, we collected longitudinal samples from severe COVID-19 patients every third to seventh day during hospitalization and every third month after recovery. We profiled the antigen-specific immune cell dynamics by combining single cell RNA-Seq, Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE)-Seq, B cell receptor (BCR)-Seq with oligo-tagged antigen baits. While the proportion of Spike Receptor Binding Domain-specific memory B cells (MBC) increased from 3 months after infection, the other Spike- and Nucleocapsid-specific B cells remained constant. All patients showed ongoing class switching and sustained affinity maturation of antigen specific cells, which was not significantly increased early after vaccine. B cell analysis revealed a polyclonal response with limited clonal expansion; nevertheless, some clones detected during hospitalization, as plasmablasts, persisted for up to one year, as MBC. Monoclonal antibodies derived from persistent B cell families increased their binding and neutralization breadth and started recognizing viral variants by 3 months after infection. Overall, our findings provide important insights into the clonal evolution and dynamics of antigen specific B cell responses in longitudinally sampled COVID-19 infected patients.
Lydia Scharf, Hannes Axelsson, Aikaterini Emmanouilidi, Nimitha R. Mathew, Daniel J. Sheward, Susannah Leach, Pauline Isakson, Ilya V. Smirnov, Emelie Marklund, Nicolae Miron, Lars-Magnus Andersson, Magnus Gisslén, Ben Murrell, Anna Lundgren, Mats Bemark, Davide Angeletti
FOXD1+ derived stromal cells give rise to pericytes and fibroblasts that support the kidney vasculature and interstitium but are also major precursors of myofibroblasts. ZEB2 is a SMAD-interacting transcription factor that is expressed in developing kidney stromal progenitors. Here we show that Zeb2 is essential for normal FOXD1+ stromal progenitor development. Specific deletion of mouse Zeb2 in FOXD1+ stromal progenitors (Zeb2 cKO) leads to abnormal interstitial stromal cell development, differentiation, and kidney fibrosis. Immunofluorescent staining analyses revealed abnormal expression of interstitial stromal cell markers MEIS1/2/3, CDKN1C, and CSPG4 (NG2) in newborn and 3-week-old Zeb2 cKO mouse kidneys. Zeb2 deficient FOXD1+ stromal progenitors also took on a myofibroblast fate that led to kidney fibrosis and kidney failure. Cell marker studies further confirmed that these myofibroblasts expressed pericyte and resident fibroblast markers including PDGFRβ, CSPG4, Desmin, GLI1, and NT5E. Notably, increased interstitial collagen deposition associated with loss of Zeb2 in FOXD1+ stromal progenitors was accompanied by increased expression of activated SMAD1/5/8, SMAD2/3, SMAD4, and AXIN2. Thus, our study identifies a key role of ZEB2 in maintaining the cell fate of FOXD1+ stromal progenitors during kidney development whereas loss of ZEB2 leads to differentiation of FOXD1+ stromal progenitors into myofibroblasts and kidney fibrosis.
Sudhir Kumar, Xueping Fan, Hila Milo Rasouly, Richa Sharma, David J. Salant, Weining Lu
Autosomal dominant polycystic kidney disease (ADPKD), the most common monogenic nephropathy, is characterized by phenotypic variability exceeding genic effects. Dysregulated metabolism and immune cell function are key disease modifiers. The tryptophan metabolites, kynurenines, produced through IDO1, are known immunomodulators. Here, we study the role of tryptophan metabolism in PKD using an orthologous disease model (C57Bl/6J Pkd1RC/RC). We found elevated kynurenine and IDO1 levels in Pkd1RC/RC kidneys versus wildtype. Further, IDO1 levels were increased in ADPKD cell lines. Genetic Ido1 loss in Pkd1RC/RC animals resulted in reduced PKD severity as measured by %kidney weight/body weight and cystic index. Consistent with an immunomodulatory role of kynurenines, Pkd1RC/RC;Ido1-/- mice presented with significant changes in the cystic immune microenvironment (CME) versus controls. Kidney macrophage numbers decreased and CD8+ T cell numbers increased, both known PKD modulators. Also, pharmacological IDO1 inhibition in Pkd1RC/RC mice and kidney specific Pkd2 knockout mice with rapidly progressive PKD resulted in less severe PKD versus controls with similar changes in the CME as in the genetic model. Our data suggest that tryptophan metabolism is dysregulated in ADPKD and that its inhibition results in changes to the CME and slows disease progression, making IDO1 a novel therapeutic target for ADPKD.
Dustin T. Nguyen, Emily K. Kleczko, Nidhi Dwivedi, Marie-Louise T. Monaghan, Berenice Y. Gitomer, Michel B. Chonchol, Eric T. Clambey, Raphael A. Nemenoff, Jelena Klawitter, Katharina Hopp
Mitochondria are dynamic organelles responsible for energy production and many processes central to cellular function. Alterations in mitochondrial function is associated with human fibrotic lung diseases, including idiopathic pulmonary fibrosis (IPF). Pulmonary fibrosis is characterized by stiffening of the extracellular matrix (ECM). Fibroblasts migrate in the direction of greater stiffness, a phenomenon termed durotaxis. The mechanically guided fibroblast migration could be a crucial step in the progression of lung fibrosis. In this study, we identified mitochondria as an important mechanotransducer at the intersection between extracellular mechanical signals and durotactic lung fibroblast migration. Primary human lung fibroblasts sense increasing matrix stiffness with a change of mitochondrial dynamics in favor of mitochondrial fission and increased production of ATP. Mitochondria polarize in the direction of a physiologically relevant stiffness gradient, with conspicuous localization to the leading edge, primarily lamellipodia and filopodia, of migrating lung fibroblasts. Matrix stiffness-regulated mitochondrial fission and durotactic lung fibroblast migration are mediated by a DRP1/MFF-dependent pathway. Importantly, we found that the DRP1/MFF pathway is activated in fibrotic lung myofibroblasts in both human IPF and bleomycin-induced mouse lung fibrosis. Our findings suggest that energy-producing mitochondria need to be sectioned via fission and repositioned in durotactic lung fibroblasts to meet the higher energy demand. This represents a new mechanism through which mitochondria may contribute to the progression of fibrotic lung diseases. Inhibition of durotactic migration of lung fibroblasts may play an important role in preventing the progression of IPF.
Ting Guo, Chun-sun Jiang, Shan-Zhong Yang, Yi Zhu, Chao He, A. Brent Carter, Veena B. Antony, Hong Peng, Yong Zhou
Although glycogen synthase kinase β (Gsk3β) has been shown to regulate tissue inflammation, whether and how it regulates inflammation resolution vs. inflammation activation is unclear. In a murine liver partial warm ischemia/reperfusion injury (IRI) model, we found that Gsk3β inhibitory phosphorylation increased at both the early activation and late resolution stages of the disease. Myeloid Gsk3β deficiency not only alleviated liver injuries, but also facilitated the restoration of liver homeostasis. Depletion of Kupffer cells (KCs) prior to the onset of liver ischemia diminished the differences between the WT and Gsk3β KO mice in the activation of liver IRI. However, the resolution of liver IRI remained accelerated in the Gsk3β KO mice. In CD11b-DTR mice, Gsk3β deficient bone marrow-derived macrophages (BMMs) facilitated the resolution of liver IRI as compared with WT cells. Furthermore, Gsk3β deficiency promoted the reparative phenotype differentiation in vivo in liver infiltrating macrophages and in vitro in BMMs. Gsk3 pharmacological inhibition promoted the resolution of liver IRI in WT, but not myeloid MerTK deficient, mice. Thus, Gsk3β regulates liver IRI at both activation and resolution stages of the disease. Gsk3 inactivation enhances the pro-resolving function of liver infiltrating macrophages in MerTK–dependent manner.
Hanwen Zhang, Ming Ni, Han Wang, Jing Zhang, Dan Jin, Ronald W. Busuttil, Jerzy W. Kupiec-Weglinski, Wei Li, Xuehao Wang, Yuan Zhai
Antibiotic-induced shifts in the indigenous gut microbiota influence normal skeletal maturation. Current theory implies that gut microbiota actions on bone occur through a direct gut-bone signaling axis. However, our prior work supports that a gut-liver signaling axis contributes to gut microbiota effects on bone. Purpose was to investigate the effects of minocycline, a systemic antibiotic treatment for adolescent acne, on pubertal/post-pubertal skeletal maturation. Sex-matched specific-pathogen-free(SPF) and germ-free(GF) C57BL/6T mice were administered a clinically relevant minocycline dose from age 6-12 weeks. Minocycline caused dysbiotic shifts in the gut bacteriome and impaired skeletal maturation in SPF mice, but did not alter the skeletal phenotype in GF mice. Minocycline administration in SPF mice disrupted the intestinal farnesoid X receptor(FXR)-fibroblast growth factor 15(FGF15) axis, a gut-liver endocrine axis supporting systemic bile acid homeostasis. Minocycline-treated SPF mice had increased serum conjugated bile acids that are FXR antagonists, suppressed osteoblast function, decreased bone mass, impaired bone microarchitecture and fracture resistance. Stimulating osteoblasts with the serum bile acid profile from minocycline-treated SPF mice recapitulated the suppressed osteogenic phenotype found in vivo, which was mediated through attenuated FXR-signaling. This work introduces bile acids as a novel mediator of gut-liver signaling actions contributing to gut microbiota effects on bone.
Matthew D. Carson, Amy J. Warner, Jessica D. Hathaway-Schrader, Vincenza L. Geiser, Joseph D. Kim, Joy E. Gerasco, William D. Hill, John J. Lemasters, Alexander V. Alekseyenko, Yongren Wu, Hai Yao, Jose I. Aguirre, Caroline Westwater, Chad M. Novince
Metastatic clear cell renal cell carcinomas (ccRCC) are resistant to DNA damaging chemotherapies, limiting therapeutic options for patients whose tumours are resistant to tyrosine kinase inhibitors and/or immune checkpoint therapies. Here we show that mouse and human ccRCC are frequently characterised by high levels of endogenous DNA damage and that cultured ccRCC cells exhibit intact cellular responses to chemotherapy-induced DNA damage. We identify that pharmacological inhibition of the DNA damage sensing kinase ATR with the orally administered, potent and selective drug M4344 (also called gartisertib) induces anti-proliferative effects in ccRCC cells due to replication stress and the accumulation of DNA damage in S phase. In some cells, DNA damage persists into subsequent G2/M and G1 phases, leading to the frequent accumulation of micronuclei. Daily single agent treatment with M4344 inhibited the growth of ccRCC xenograft tumours. M4344 synergises with chemotherapeutic drugs including cisplatin and carboplatin and the PARP inhibitor olaparib in mouse and human ccRCC cells. Weekly M4344 plus cisplatin treatment showed in vivo therapeutic synergy in ccRCC xenografts and was efficacious in an autochthonous mouse ccRCC model. These studies identify ATR inhibition as a potential novel therapeutic option for ccRCC.
Philipp Seidel, Anne Rubarth, Kyra Zodel, Asin Peighambari, Felix Neumann, Yannick Federkiel, Hsin Huang, Rouven Hoefflin, Mojca Adlesic, Christian Witt, David J. Hoffmann, Patrick Metzger, Ralph K. Lindemann, Frank T. Zenke, Christoph Schell, Melanie Boerries, Dominik von Elverfeldt, Wilfried Reichardt, Marie Follo, Joachim Albers, Ian J. Frew
Carbohydrate Responsive Element-Binding Protein (ChREBP) is a carbohydrate sensing transcription factor that regulates both adaptive and maladaptive genomic responses in coordination of systemic fuel homeostasis. Genetic variants in the ChREBP locus associate with diverse metabolic traits in humans, including circulating lipids. To identify novel ChREBP-regulated hepatokines that contribute to its systemic metabolic effects, we integrated ChREBP ChIP-seq analysis in mouse liver with human genetic and genomic data for lipid traits and identified Hepatocyte Growth Factor Activator (HGFAC) as a promising ChREBP-regulated candidate in mice and humans. HGFAC is a protease that activates the pleiotropic hormone Hepatocyte Growth Factor (HGF). We demonstrate that HGFAC KO mice have phenotypes concordant with putative loss-of-function variants in human HGFAC. Moreover, in gain- and loss-of-function genetic mouse models, we demonstrate that HGFAC enhances lipid and glucose homeostasis, which may be mediated in part through actions to activate hepatic PPARγ activity. Together, our studies show that ChREBP mediates an adaptive response to overnutrition via activation of HGFAC in the liver to preserve glucose and lipid homeostasis.
Ashot Sargsyan, Ludivine Doridot, Sarah Anissa Hannou, Wenxin Tong, Harini Srinivasan, Rachael Ivison, Ruby Monn, Henry H. Kou, Jonathan M. Haldeman, Michelle Arlotto, Phillip J. White, Paul A. Grimsrud, Inna Astapova, Linus T.-Y. Tsai, Mark A. Herman
BACKGROUND. At the onset of exercise, the speed at which PCr decreases towards a new steady state (PCr on-kinetics), reflects the readiness to activate mitochondrial ATP synthesis, which is secondary to Acetyl-CoA availability in skeletal muscle. We hypothesized that PCr on-kinetics are slower in metabolically compromised and older individuals, and associated with low carnitine acetyl-transferase (CrAT) protein activity and compromised physical function. METHODS. We applied 31P-Magnetic Resonance Spectroscopy (MRS) to assess PCr on-kinetics in two cohorts of human volunteers. Cohort 1: patients with type 2 diabetes, obese, lean trained and untrained individuals. Cohort 2: young and older individuals with normal physical activity and older trained. Previous results of CrAT protein activity and acetylcarnitine content in muscle tissue were used to explore the underlying mechanisms of PCr on-kinetics, along with various markers of physical function. RESULTS. PCr on-kinetics were significantly slower in metabolically compromised and older individuals (indicating mitochondrial inertia) as compared to young and older trained volunteers, regardless of in vivo skeletal muscle oxidative capacity (P<0.001). Mitochondrial inertia correlated with reduced CrAT protein activity, low acetylcarnitine content and also with functional outcomes (P<0.001). CONCLUSION. PCr on-kinetics are significantly slower in metabolically compromised and older individuals with normal physical activity compared to young and older trained, regardless of in vivo skeletal muscle oxidative capacity, indicating greater mitochondrial inertia. Thus, PCr on-kinetics are a currently unexplored signature of skeletal muscle mitochondrial metabolism, tightly linked to functional outcomes. Skeletal muscle mitochondrial inertia might emerge as a target of intervention to improve physical function. TRIAL REGISTRATION. clinicaltrials.gov: NCT01298375 and clinicaltrials.gov: NCT03666013. FUNDING. R.M and M.H were granted with an EFSD/Lilly grant from the European Foundation for the Study of Diabetes (EFSD). V.S was supported by an ERC staring grant (Grant no. 759161) "MRS in Diabetes".
Rodrigo F. Mancilla, Lucas Lindeboom, Lotte Grevendonk, Joris Hoeks, Timothy R. Koves, Deborah M. Muoio, Patrick Schrauwen, Vera Schrauwen-Hinderling, Matthijs K.C. Hesselink
Chronic inflammation is associated with lung tumorigenesis, in which NF-κB-mediated epigenetic regulations play a critical role. Lung tumor suppressor GPRC5A is repressed in most non-small cell lung cancer (NSCLC), however the mechanisms remain unclear. Here, we show that NF-κB acts as a transcriptional repressor in suppression of GPRC5A. NF-κB induces GPRC5A repression both in vitro and in vivo. Intriguingly, trans-activation of NF-κB downstream targets is not required, but the trans-activation domain of RelA/p65 was required for GPRC5A repression. NF-κB did not bind to any potential cis-element in GPRC5A promoter. Instead, p65 was complexed with RARα/β, and recruited to the RA-response element (RARE) site at the GPRC5A promoter, resulting in disrupted RNA polymerase II complex, and suppressed transcription. Noticeably, phosphorylation on Serine276 of p65 is required for interaction with RARα/β and repression of GPRC5A. Moreover, NF-κB-mediated epigenetic repression is through suppression of histone H3K9ac, but not DNA methylation of the CpG islands, at the GPRC5A promoter. Consistently, a HDAC inhibitor, but not DNA methylation inhibitor, restored GPRC5A expression in NSCLC cells. Thus, NF-κB induces transcriptional repression of GPRC5A via complex with RARα/β and mediates epigenetic repression via suppression of H3K9ac.
Hongyong Song, Xiaofeng Ye, Yueling Liao, Siwei Zhang, Dongliang Xu, Shuangshuang Zhong, Bo Jing, Tong Wang, Beibei Sun, Jianhua Xu, Wenzheng Guo, Kaimi Li, Min Hu, Yanbin Kuang, Jing Ling, Tuo Zhang, Yadi Wu, Jing Du, Feng Yao, Yugene Chin, Qi Wang, Binhua P. Zhou, Jiong Deng
Despite the efficacy of tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML), malignant long-term hematopoietic stem cells (LT-HSC) persist as a source of relapse. However, LT-HSC are heterogenous and the most primitive, drug-resistant LT-HSC subpopulations are not well characterized. In normal hematopoiesis, self-renewal and long-term reconstitution capacity is enriched within LT-HSCs with low c-Kit expression (c-KitLow). Here, using a transgenic CML mouse model, we found that long-term engraftment and leukemogenic capacity were restricted to c-KitLow CML LT-HSC. CML LT-HSC demonstrated enhanced differentiation with expansion of mature progeny following exposure to the c-Kit ligand, stem cell factor (SCF). Conversely, SCF deletion led to depletion of normal LT-HSC but increase in c-KitLow and total CML LT-HSC with reduced generation of mature myeloid cells. CML c-KitLow LT-HSC showed reduced cell cycling, and expressed enhanced quiescence and inflammatory gene signatures. SCF administration led to enhanced depletion of CML primitive progenitors but not LT-HSC after TKI treatment. Human CML LT-HSC with low or absent c-Kit expression were markedly enriched after TKI treatment. We conclude that CML LT-HSC expressing low c-Kit levels are enriched for primitive, quiescent, drug-resistant leukemia initiating cells and represent a critical target for eliminating disease persistence.
Mansi Shah, Harish Kumar, Shaowei Qiu, Hui Li, Mason Harris, Jianbo He, Ajay Abraham, David K. Crossman, Andrew Paterson, Robert S. Welner, Ravi Bhatia
Diamond–Blackfan anemia (DBA) is a genetic blood disease caused by heterozygous loss-of-function mutations in ribosomal protein (RP) genes, most commonly RPS19. The signature feature of DBA is hypoplastic anemia occurring in infants, although some older patients develop multi-lineage cytopenias with bone marrow hypocellularity. The mechanism of anemia in DBA is not fully understood and even less is known about the pancytopenia that occurs later in life, in part because patient hematopoietic stem and progenitor cells (HSPCs) are difficult to obtain, and the current experimental models are suboptimal. We modeled DBA by editing healthy human donor CD34+ HSPCs with CRISPR/Cas9 to create RPS19 haploinsufficiency. In vitro differentiation revealed normal myelopoiesis and impaired erythropoiesis, as observed in DBA. After transplantation into immunodeficient mice, bone marrow repopulation by RPS19+/− HSPCs was profoundly reduced, indicating hematopoietic stem cell (HSC) impairment. The erythroid and HSC defects resulting from RPS19 haploinsufficiency were partially corrected by transduction with an RPS19-expressing lentiviral vector or by Cas9 disruption of TP53. Our results define a tractable, biologically relevant experimental model of DBA based on genome-editing of primary human HSPCs and they identify an associated HSC defect that emulates the pan-hematopoietic defect of DBA.
Senthil Velan Bhoopalan, Jonathan S. Yen, Thiyagaraj Mayuranathan, Kalin D. Mayberry, Yu Yao, Maria Angeles Lillo Osuna, Yoonjeong Jang, Janaka S.S. Liyange, Lionel Blanc, Steven R. Ellis, Marcin W. Wlodarski, Mitchell J. Weiss
We determined whether gut microbiota-produced trimethylamine (TMA) is oxidized into trimethylamine N-oxide (TMAO) in non-liver tissues, whether TMAO promotes inflammation via trained immunity (TI) and made the following findings: Endoplasmic reticulum (ER) stress genes were co-upregulated with mitoCarta genes in chronic kidney diseases (CKD); TMAO upregulated 190 genes in human aortic endothelial cells (HAECs); TMAO synthesis enzyme flavin-containing monooxygenase 3 (FMO3) was expressed in human and mouse aortas,;4) TMAO trans-differentiated HAECs into innate immune cells; TMAO phosphorylated 12 kinases in cytosol via its receptor PERK and CREB, and integrated with PERK pathways; and PERK inhibitors suppressed TMAO-induced ICAM-1; TMAO upregulated 3 mitochondrial genes and downregulated inflammation inhibitor DARS2, induced mitoROS; and mitoTEMPO inhibited TMAO-induced ICAM-1; and -glucan priming followed by TMAO re-stimulation upregulated TNF-α by inducing metabolic reprogramming; and glycolysis inhibitor suppressed TMAO-induced ICAM-1. Our results have provided novel insights over TMAO roles in inducing EC activation and innate immune trans-differentiation, inducing metabolic reprogramming and TI for enhanced vascular inflammation and new therapeutic targets for treating cardiovascular diseases (CVD), CKD-promoted CVD, inflammations, transplantation, aging, and cancers.
Fatma Saaoud, Lu Liu, Keman Xu, Ramon Cueto, Ying Shao, Yifan Lu, Yu Sun, Nathaniel W. Snyder, Sheng Wu, Ling Yang, Yan Zhou, David L. Williams, Chuanfu Li, Laisel Martinez, Roberto I. Vazquez-Padron, Huaqing Zhao, Xiaohua Jiang, Hong Wang, Xiaofeng Yang
Systemic iron metabolism is disrupted in chronic kidney disease (CKD). However, little is known about local kidney iron homeostasis and its role in kidney fibrosis. Kidney-specific effects of iron therapy in CKD also remain elusive. Here, we elucidate the role of macrophage iron status in kidney fibrosis and demonstrate that it is a potential therapeutic target. In CKD, kidney macrophages exhibited depletion of labile iron pool (LIP) and induction of transferrin receptor 1, indicating intracellular iron deficiency. Low LIP in kidney macrophages was associated with their defective antioxidant response and pro-inflammatory polarization. Repletion of LIP in kidney macrophages through knockout of ferritin heavy chain (Fth1) reduced oxidative stress and mitigated fibrosis. Similar to Fth1 knockout, iron dextran therapy, through replenishing macrophage LIP, reduced oxidative stress, decreased the production of pro-inflammatory cytokines, and alleviated kidney fibrosis. Interestingly, iron significantly decreased TGF-β expression and suppressed TGF-β-driven fibrotic response of macrophages. Iron dextran therapy and FtH suppression had an additive protective effect against fibrosis. Adoptive transfer of iron-loaded macrophages alleviated kidney fibrosis, confirming the protective effect of iron-replete macrophages in CKD. Thus, targeting intracellular iron deficiency of kidney macrophages in CKD can serve as a therapeutic opportunity to mitigate disease progression.
Edwin Patino, Divya Bhatia, Steven Z. Vance, Ada Antypiuk, Rie Uni, Chantalle Campbell, Carlo G. Castillo, Shahd Jaouni, Francesca Vinchi, Mary E. Choi, Oleh Akchurin
Loss of olfactory function has been commonly reported in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections. Recovery from anosmia is not well understood. Previous studies showed that sustentacular cells, and occasionally, olfactory sensory neurons (OSNs) in the olfactory epithelium (OE) are infected in SARS-CoV-2-infected patients and experimental animals. Here, we show that SARS-CoV-2 infection of sustentacular cells induces inflammation characterized by infiltration of myeloid cells to the olfactory epithelium and variably increased expression of proinflammatory cytokines. We observed widespread damage to, and loss of cilia on, OSNs, accompanied by downregulation of olfactory receptors and signal transduction molecules involved in olfaction. A consequence of OSN dysfunction was a reduction in the number of neurons in the olfactory bulb expressing tyrosine hydroxylase, consistent with reduced synaptic input. Resolution of the infection, inflammation, and olfactory dysfunction occurred over 3-4 weeks following infection in most but not all animals. We also observed similar patterns of OE infection and anosmia/hyposmia in mice infected with other human coronaviruses such as SARS-CoV and MERS-CoV. Together, these results define the downstream effects of sustentacular cell infection and provide insight into olfactory dysfunction in COVID-19-associated anosmia.
Abhishek Kumar Verma, Jian Zheng, David K. Meyerholz, Stanley Perlman